Synthesis and molecular and electronic structures of a series of Mo3CoSe4 cluster complexes with three different metal electron populations.

2008

The synthesis, crystal structure, and magnetic properties of [Mo 3(CoCO)Se 4(dmpe) 3Cl 3] ( 1), [Mo 3(CoCl)Se 4(dmpe) 3Cl 3] ( 2), and [Mo 3(CoCl)Se 4(dmpe) 3Cl 3](TCNQ) ([ 2](TCNQ)) (dmpe = 1,2-bis(dimethylphosphanyl)ethane; TCNQ = 7,7,8,8-tetracyanoquinomethane) cubane-type complexes with 16, 15, and 14 metal electrons, respectively, are reported. These compounds complete the series of cobalt-containing Mo 3CoQ 4 (Q = S, Se) cubane-type complexes, which allows a complete analysis of the consequences of replacing the inner chalcogen and the metal electron count on the structural, magnetic, and electrochemical properties. The experimental evidence is theoretically supported and rationalized…

Synthesis, molecular structures and EPR spectra of the paramagnetic cuboidal clusters with Mo3S4Ga cores

2017

Electron precise [Mo3(l3-S)(l-S)3(diphos)3Br3]Br (diphos = dppe, dmpe) incomplete cuboidal clusters with six cluster skeletal electrons (CSE) were converted into paramagnetic cuboidal [Mo3(GaBr)(l3-S)4- (diphos)3Br3] clusters by treatment with elemental Ga. The new heterobimetallic complexes with nine CSE possess a doublet ground state with the unpaired electron density delocalized over the three molybdenum atoms.

Alternating Ferro/Antiferromagnetic Copper(II) Chain Containing an Unprecedented Triple Formato/Hydroxido/Sulfato Bridge.

2016

The first example of a triple formato/hydroxido/sulfato (FHS) bridge for any metal is reported in compound [Cu2(bpym)(OH)(HCO2)(SO4)(H2O)2]·3H2O (1). Its structure shows the presence of alternating triple FHS bridges and 2,2'-bipyrimidine (bpym) ones. Although in the initial synthesis the sulfate anions were introduced accidentally, here we report the rational synthesis and the magnetic properties of this compound. The magnetic properties show that 1 is an alternating ferro/antiferromagnetic (F/AF) chain compound with predominant antiferromagnetic interactions and were fit to an alternating F/AF S = (1)/2 chain with g = 2.103, JAF = -139 cm(-1), and JF = 116 cm(-1) (α = JF/|JAF| = 0.83). Th…

Incommensurate nature of the multilayered molecular ferromagnetic metals based on bis(ethylenedithio)tetrathiafulvalene and bimetallic oxalate comple…

2004

The salt [ET]x[MnRh(ox)(3)].CH(2)Cl(2) (x = 2.526(1)) has been obtained and characterized. This paramagnetic metal is essentially isostructural to the ferromagnetic metal [ET]y[MnCr(ox)(3)].CH(2)Cl(2) (y approximately equal to 3) and provides a definite answer on the origin of the structural disorder present on such systems. As in the ferromagnetic analogue, this material shows high electrical conductivity at room temperature (13 S.cm(-1)) and metallic behavior.

Rare trinuclear NiII2MII complexes (MII = Mn, Fe and Co) with a reduced Schiff base ligand: Synthesis, structures and magnetic properties

2018

Abstract Three new trinuclear hetero-metallic NiII2MII complexes with MII = Mn, Fe and Co have been synthesized using a [NiLR] “metalloligand”, where H2LR = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine. All complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD and magnetic and electrochemical studies. In the three complexes, in addition to the double phenoxido bridges, the two terminal NiII atoms are linked to the central MII [M = Mn(1), Fe(2) and Co(3)] ion by means of a bridging carboxylato co-anion, giving rise to a linear NiII-MII-NiII structure. Variable temperature magnetic susceptibility measurements show the presence of weak ferromagnetic…

Koexistenz mobiler und lokalisierter Elektronen in Salzen des Bis(ethylen)dithiotetrathiafulvalen-Radikals (BEDT-TTF) mit paramagnetischen Polyoxomet…

1994

Design of molecular materials combining magnetic, electrical and optical properties †

2000

The possibilities offered by hybrid functional materials formed by two molecular networks in the context of crystal engineering are illustrated with two different examples: (i) hybrid magnets constructed from combination of an extended ferromagnetic or ferrimagnetic inorganic network, with a molecular paramagnetic metal complex acting as template. (ii) Hybrid organic–inorganic compounds combining an organic π-electron donor network that furnishes the pathway for electronic conductivity, with inorganic metal complexes that act as structural and/or magnetic components. These examples illustrate how this hybrid approach allows the design of molecular materials combining non-conventional magnet…

Structural Variation and Magneto-Structural Correlation in Two New Dinuclear Bis(µ2-Phenoxo)-Bridged CuII Schiff-Base Complexes: Catalytic Potential …

2010

Two new dinuclear bis(μ2-phenoxo)-bridged copper(ii) complexes [Cu(NCS)L1]2 (1) and [Cu(NCS)L2]2 (2) have been synthesized using two tridentate NNO-donor Schiff-base ligands, L1H (Me2N(CH2)3N=CHC6H3(OMe)(OH)) and L2H (Me2N(CH2)3N=C(CH3)C6H4(OH)), respectively. They have been characterized by elemental analyses, IR, UV-visible, and electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry, and magnetic susceptibility measurements. X-Ray single-crystal structures reveal a central Cu2O2 core in each complex with an isothiocyanate ligand coordinated terminally to each metal centre. The coordination environments around the CuII ions in 1 and 2 are a distorted trigonal bipyramid and…

Towards Molecular Conductors with a Spin‐Crossover Phenomenon:Crystal Structures, Magnetic Properties and Mössbauer Spectra of[Fe(salten)Mepepy][M(dm…

2005

Three new iron(III) compounds of formula [Fe(salten)Mepepy][M(dmit)2]·CH3CN (M = Ni, Pd, Pt; H2salten = 4-azaheptamethylene-1,7-bis(salicylideneiminate); Mepepy = 1-(pyridin-4-yl)-2-(N-methylpyrrol-2-yl) ethane; dmit2– = 1,3-dithiole-2-thione-4,5-dithiolato) have been synthesised and the crystal structure of each compound has been solved at different temperatures. The structures consist of alternating layers of [M(dmit)2]– units and [Fe(salten)Mepepy] cations. In the Ni compound photo-isomerisation of the Mepepy ligand can be observed in dichloromethane solution. The temperature dependence of the magnetic susceptibility of the compounds reveals a gradual S = 5/2 blabla S = 1/2 spin crossove…

A Novel 1D-AF Hybrid Organic-Inorganic Chromium(II) Methyl Phosphonate Dihydrate: Synthesis, X-Ray Crystal and Molecular Structure, and Magnetic Prop…

2010

Light-blue crystals of chromium(II) methyl phosphonate dihydrate, [Cr(CH(3)PO(3))(H(2)O)].H(2)O, were obtained in water by mixing filtered solutions of methylphosphonic acid and chromium(II) chloride in the presence of urea in an inert atmosphere. The compound was characterized by elemental analysis, TGA-DSC, X-ray crystallography, magnetic measurements, and UV-visible and FT-IR spectroscopies. The crystal and molecular structures (orthorhombic Pnma (no. 62): a = 4.4714(5) A, b = 6.8762(7) A, c = 19.180(2) A, Z = 4) have been solved using single-crystal X-ray diffraction. The chromium(II) ion is six-coordinated by oxygens (4 + 2) to form an elongated octahedron, with the four equatorial oxy…

Breaking Bonds and Forming Nanographene Diradicals with Pressure.

2017

New anthanthrone-based polycyclic scaffolds possessing peripheral crowed quinodimethanes have been prepared. While the compounds adopt a closed-shell butterfly shaped structure in the ground state, a concave-to-convex fluxional dynamic inversion is accessible with a low energy barrier through an open-shell diradicaloid transition-state. Mainly driven by the release of strainattributed to the steric hindrance at the peri position of the anthanthrone core, a low-lying open-shell diradical is accessible through planarization of the core, which can be achieved by thermal excitation in solution. Alternatively, planarization can be achieved by application of mild pressure in the solid state, in w…

A spin-crossover complex based on a 2,6-bis(pyrazol-1-yl)pyridine (1-bpp) ligand functionalized with a carboxylate group

2014

Combining Fe(ii) with the carboxylate-functionalized 2,6-bis(pyrazol-1-yl)pyridine (bppCOOH) ligand results in the spin-crossover compound [Fe(bppCOOH)2](ClO4)2 which shows an abrupt spin transition with a T1/2 of ca. 380 K and a TLIESST of 60 K due to the presence of a hydrogen-bonded linear network of complexes.

3D-transition metal mono-substituted Keggin polyoxotungstate with an antenna molecule: synthesis, structure and characterization

2008

Three new organic-inorganic hybrid complexes based on 3d-transition metal monosubstituted Keggin polyoxometalates (POMs) with imidazole (Im) as pendant ligands, formulated as (HIm)(6-)[SiW11O39NiIm]0.8[SiW11O39Ni(H2O)]0.2.7H2O (1), (Im)4Na6[SiW11O39MnIm]0.69[SiW11O39Mn(H2O)]0.31.7.5H2O (2) and (HIm)6[SiW11O39CoIm]0.63[SiW11O39Co(H2O)]0.37.7H2O (3), have been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy, elemental analysis, TG analysis, cyclic voltammetry, magnetic properties, EPR and single-crystal/powder X-ray diffraction. The structural analyses indicate that the 3d metal atoms are incorporated into the vacancy of the alpha-[SiW11O39](8-) (SiW11). Complexes 1-…

Electrical conductivity and strong luminescence in copper Iodide double chains with isonicotinato derivatives

2015

Direct reactions between CuI and isonicotinic acid (HIN) or the corresponding esters, ethyl isonicotinate (EtIN) or methyl isonicotinate (MeIN), give rise to the formation of the coordination polymers [CuI(L)] with L=EtIN (1), MeIN (2) and HIN (3). Polymers 1-3 show similar structures based on a CuI double chain in which ethyl-, methyl isonicotinate or isonicotinic acid are coordinated as terminal ligands. Albeit, their supramolecular architecture differs considerably, affecting the distances and angles of the central CuI double chains and thereby their physical properties. Hence, the photoluminescence shows remarkable differences; 1 and 2 show a strong yellow emission, whereas 3 displays a…

Photochemical behavior in azobenzene having acidic groups. Preparation of magnetic photoresponsive gels

2011

[EN] The photochemistry of three azobenzenes representing contrasting photochemical behaviors is described in the present work. Thus, Methyl Orange (MO, 4-[[(4-dimethylamino)phenyl]-azo]benzenesulfonic acid sodium salt, hereinafter (1) and 4-hydroxyazobenzene-4'-sulfonic acid (2) undergo in water fast photochemical proton shift, with decays in the microsecond timescale. In contrast to the previous cases, azobenzene-4,4'-dicarboxylic acid (3) undergoes photoisomerization in water. This photochemical behavior allows the preparation of aqueous gels with Aerosil as gelating agent (5% weight) exhibiting high cyclability and photoreversible isomerization of the trans to cis (300 nm irradiation) a…

Effect of temperature and ligand protonation on the electronic ground state in Cu( ii ) polymers having unusual secondary interactions: a magnetic an…

2018

International audience; Two new copper(II) polymeric complexes, {[Cu(HPymat)(H2O)](NO3)}n (1) and [Cu2(Pymat)2(H2O)3]n (2), have been synthesized using the Schiff base ligand H2Pymat [H2Pymat = (E)-2-(1-(pyridin-2-yl)-methyleneamino)terephthalic acid]. Complex 1 is a cationic 1D polymer, whereas complex 2 is a two dimensional polymer. Both complexes were crystallographically, spectroscopically and magnetically characterized. Theoretical studies were performed and the catecholase activity of the complexes was also examined. Complex 1 is a ferromagnetically coupled complex with J = 2.8 cm−1 and 2 shows antiferromagnetic coupling with J = −1.6 cm−1. Both complexes show notable features in the …

Coordination polymers based on bridging cyanocarbanions and bis-tridentate p-phenylenediamine ligands

2017

Two new Cu(II) coordination polymeric neutral chains of formula [Cu 2 (1,4-tpbd)(μ-A) 2 (H 2 O) 2 ](A) 2 with A = tcnoet − ( 1 ) and tcnopr − ( 2 ) (1,4-tpbd =  N,N,N′N′ -tetrakis(2-pyridylmethyl)benzene-1,4-diamine, tcnoet −  = 1,1,3,3-tetracyano-2-ethoxypropenide and tcnopr −  = 1,1,3,3-tetracyano-2-propoxypropenide) have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. 1  and  2 show alternating chains where the 1,4-tpbd and the cyanocarbanion units (tcnoet − for 1 and tcnopr − for 2 ) alternate as bridging ligands. The molecular structure can be viewed as [Cu 2 (μ-tpbd)] 4+ dinuclear units (with Cu⋯Cu distances of 8.2233(3) for 1 …

Heptanuclear hydroxo-bridged copper cluster of the dicubane-like type: structural and magnetic characterisations of [Cu7(OH)6Cl2(pn)6(H2O)2](C(CN)3)4…

2002

A new polynuclear copper(II) complex [Cu7(OH)6Cl2- (pn)6(H2O)2](C(CN)3)4Cl2 with hydroxo-bridging ligands has been prepared; the centrosymmetric cluster cation can be described as two Cu4O3Cl distorted cubane units sharing one copper cation. Clemente Juan, Juan Modesto, Juan.M.Clemente@uv.es ; Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es

Solvent-Induced Delamination of a Multifunctional Two Dimensional Coordination Polymer

2012

A coordination polymer is fully exfoliated by solvent-assisted interaction only. The soft-delamination process results from the structure of the starting material, which shows a layered structure with weak layer-to-layer interactions and cavities with the ability to locate several solvents in an unselective way. These results represent a significant step forward towards the production of structurally designed one-molecule thick 2D materials with tailored physico-chemical properties.

Single-Component Magnetic Conductors Based on Mo3S7 Trinuclear Clusters with Outer Dithiolate Ligands

2004

A trinuclear cluster complex containing the Mo(3)S(7) central unit coordinated to dithiolate ligands, in particular the organic dmit (1,3-dithia-2-thione-4,5-dithiolate) anion, has been used to prepare a single-component molecular conductor formed by the threefold symmetry magnetic building block Mo(3)S(7)(dmit)(3) (1). The [Mo(3)S(7)(dmit)(3)](2)(-) ([1](2)(-)) diamagnetic anion forms dimers by interaction between the electrophilic cluster axial sulfur atoms and the sulfur atoms of the outer dithiolate ligand. Additional contacts between adjacent dmit ligands result in chain formation. The two-electron oxidation of [1](2)(-) yields to a three-dimensional molecular solid formed by neutral M…

Use of a reduced Schiff-Base ligand to prepare novel chloro-bridged chains of rare Cu(II) trinuclear complexes with mixed azido/oxo and chloro/oxo br…

2010

Two mixed bridged one-dimensional (1D) polynuclear complexes, [Cu(3)L(2)(mu(1,1)-N(3))(2)(mu-Cl)Cl](n) (1) and {[Cu(3)L(2)(mu-Cl)(3)Cl].0.46CH(3)OH}(n) (2), have been synthesized using the tridentate reduced Schiff-base ligand HL (2-[(2-dimethylamino-ethylamino)-methyl]-phenol). The complexes have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. In both complexes the basic trinuclear angular units are joined together by weak chloro bridges to form a 1D chain. The trinuclear structure of 1 is composed of two terminal square planar [Cu(L)(mu(1,1)-N(3))] units connected by a central Cu(II) atom through bridging nitrogen atoms of end…

New Route to Polynuclear Ni(II) and Cu(II) Complexes with Bridging Oxime Groups That Are Inaccessible by Conventional Preparations

2019

A series of new polynuclear complexes of divalent Ni and Cu with 2-cyano-2-oximino-acetic acid (later AACO2-) were obtained as the result of the ligand modification reaction in the process of complexation, using 2-cyano-2-oximino-acetates such as methyl- (later as MeCO), and ethyl- (as ECO later on). Synthesized compounds were characterized by spectroscopic methods, thermal analysis, magnetochemistry, and X-ray crystallography. Crystal data revealed the formation of the dimeric [Ni(AACO)(H2O)3]2·H2O (1), trimeric K2[Ni3(AACO)4(H2O)4]·4H2O (2), and K2[Cu3(AACO)4(H2O)4]·4H2O (3) complexes, with bridging NO-groups cyanoxime dianions. In the latter two compounds, the AACO2– anions adopt cis-arr…

Rational Design of Copper(II)-Uracil Nanoprocessed Coordination Polymers to Improve Their Cytotoxic Activity in Biological Media

2021

This work is focused on the rational structural design of two isostructural Cu(II) nano-coordination polymers (NCPs) with uracil-1-acetic acid (UAcOH) (CP1n) and 5-fluorouracil-1-acetic acid (CP2n). Suitable single crystals for ꭕ-ray diffraction studies of CP1 and CP2 were prepared under hydrothermal conditions, enabling their structural determination as 1D-CP ladder-like polymeric structures. The control of the synthetic parameters allows their processability into water colloids based on nanoplates (CP1n and CP2n). These NCPs are stable in water at physiological pHs for long periods. However, interestingly, CP1n is chemically altered in culture media. These transformations provoke the part…

Magnetoresistance studies of the ferromagnetic molecular metal (BEDT-TTF)3[MnCr(C2O4)3] under pressure

2003

(BEDT-TTF)3[MnCr(C2O4)3] is the first ferromagnetic molecular metal, in which organic layers of BEDT-TTF alternate with infinite layers of the bimetallic oxalate complex [MnCr(C2O4)3]-. While the bimetallic layer undergoes a magnetic phase transition into a canted ferromagnetic state at 5.5 K, the metallic character of the conductivity is not affected by the magnetic transition [Nature 408 (2000) 447]. We performed magnetoresistance measurements (B≤17 T) at low temperatures (T≥900 mK) and under hydrostatic pressures of up to 2.0 GPa. Oscillations in the magnetoresistance develop under pressure that can be interpreted as Shubnikov-de Haas oscillations, if an internal magnetic field is taken …

A Heterobimetallic Anionic 3,6-Connected 2D Coordination Polymer Based on Nitranilate as Ligand

2016

In order to synthesize new coordination polymers with original architectures and interesting magnetic properties, we used the nitranilate ligand (C₆O₄(NO₂)₂2- = C₆N₂O₈2-), derived from the dianionic ligand dhbq2- (2,5-dihydroxy-1,4-benzoquinone = H₂C₆O₄2-). The use of this bis-bidentate bridging ligand led to [(DAMS)₂{FeNa(C₆N₂O₈)₃}·CH₃CN]n (1) (DAMS⁺ = C16H17N₂⁺ = 4-[4-(dimethylamino)-α-styryl]-1-methylpyridinium), a 2D heterometallic coordination polymer presenting an unprecedented structure for any anilato-based compound. This structural type is a 3,6-connected 2D coordination polymer derived from the well-known honeycomb hexagonal structure, where Fe(III) ions alternate with Na⁺ dimers …

Unusual Magnetic Behavior in the Layered Ferromagnet [Ni(C6H14N2)2]3[Fe(CN)6]2·2H2O

2002

The cyano-bridged molecular complex [Ni(C6H14N2)2]3[Fe(CN)6]2·2H2O, with a rectangular 2D structure, displays long-range ferromagnetic ordering at 14 K, and exhibits unusual magnetic properties for this type of material, as confirmed by the appearance of two different peaks in the AC magnetic susceptibility plot, and a high coercive field (2.3 kOe) and remnant magnetization (6.8 μB). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Increasing the Nuclearity of Magnetic Polyoxometalates. Syntheses, Structures, and Magnetic Properties of Salts of the Heteropoly Complexes [Ni3(H2O)…

1998

The rational synthesis and the structural and magnetic characterization of three different nickel clusters encapsulated in Keggin trivacant fragments are presented. The three complexes show how it is possible to increase the nuclearity of the clusters (from 3 and 4 to 9) by slightly changing the synthetic conditions. These three anionic clusters crystallize as mixed salts of K+ and Na+. The trimeric complex [Ni3(H2O)3PW10O39H2O]7- (Ni3) crystallizes in the triclinic space group P1 (a = 10.896(6) A, b = 12.869(5) A, c = 20.373(6) A, α = 94.67(6)°, β = 101.12(8)°, γ = 110.72(8)°, Z = 2) and presents a ferromagnetic triangular cluster. The tetranuclear complex [Ni4(H2O)2(PW9O34)2]10- (Ni4) cry…

Molecule Isomerism Modulates the Diradical Properties of Stable Singlet Diradicaloids

2019

Inclusion of quinoidal cores in conjugated hydrocarbons is a common strategy to modulate the properties of diradicaloids formed by aromaticity recovery within the quinoidal unit. Here we describe an alternative approach of tuning of diradical properties in indenoindenodibenzothiophenes upon anti → syn isomerism of the benzothiophene motif. This alters the relationship of the S atom with the radical center from linear to cross conjugation yet retains the same 2,6-naphtho conjugation pattern of the rearomatized core. We conduct a full comparison between the anti and syn derivatives based on structural, spectroscopic, theoretical, and magnetic measurements, showing that these systems are stabl…

Reversible Dimerization and Polymerization of a Janus Diradical To Produce Labile C−C Bonds and Large Chromic Effects

2016

Conducting polymers can be synthesized by irreversible diradical monomer polymerization. A reversible version of this reaction consisting of the formation/dissociation of σ‐dimers and σ‐polymers from a stable quinonoidal diradical precursor is described. The reaction reversibility is made by a quinonoidal molecule which changes its structure to an aromatic species by forming weak and long intermolecular C−C single bonds. The reaction provokes a giant chromic effect of about 2.5 eV. The two opposite but complementary quinonoidal and aromatic tautomers provide the Janus faces of the reactants and products which produces the observed chromic effect. A reaction mechanism is proposed to explain …

Synthesis and Physical Properties of K4[Fe(C5O5)2(H2O)2](HC5O5)2·4H2O (C5O52– = Croconate): A Rare Example of Ferromagnetic Coupling via H-bonds

2012

The reaction of the croconate dianion (C(5)O(5))(2-) with a Fe(III) salt has led, unexpectedly, to the formation of the first example of a discrete Fe(II)-croconate complex without additional coligands, K(4)[Fe(C(5)O(5))(2)(H(2)O)(2)](HC(5)O(5))(2)·4H(2)O (1). 1 crystallizes in the monoclinic P2(1)/c space group and presents discrete octahedral Fe(II) complexes coordinated by two chelating C(5)O(5)(2-) anions in the equatorial plane and two trans axial water molecules. The structure can be viewed as formed by alternating layers of trans-diaquabis(croconato)ferrate(II) complexes and layers containing the monoprotonated croconate anions, HC(5)O(5)(-), and noncoordinated water molecules. Both …

Functional Hybrid Materials Containing Polypyrrole and Polyoxometalate Clusters: Searching for High Conductivities and Specific Charges

2002

Slow Relaxation of the Magnetization in Anilato-Based Dy(III) 2D Lattices.

2021

The search for two- and three-dimensional materials with slow relaxation of the magnetization (single-ion magnets, SIM and single-molecule magnets, SMM) has become a very active area in recent years. Here we show how it is possible to prepare two-dimensional SIMs by combining Dy(III) with two different anilato-type ligands (dianions of the 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone: C6O4X22−, with X = H and Cl) in dimethyl sulfoxide (dmso). The two compounds prepared, formulated as: [Dy2(C6O4H2)3(dmso)2(H2O)2]·2dmso·18H2O (1) and [Dy2(C6O4Cl2)3(dmso)4]·2dmso·2H2O (2) show distorted hexagonal honeycomb layers with the solvent molecules (dmso and H2O) located in the interlayer space and…

Exchange Coupling Mediated by N–H···Cl Hydrogen Bonds: Experimental and Theoretical Study of the Frustrated Magnetic System in Bis(o-phenylenediamine…

2012

The title compound crystallizes in the monoclinic P2(1)/c space group with a = 11.2470(3) A, b = 5.9034(2) A, c = 12.0886(3) A, β = 115.143(1)°, and V = 726.58(4) A(3) and consists of discrete monomeric NiCl(2)(o-phenylendiamine)(2) molecules. Each o-phen ligand coordinates in a bidentate mode with the chloride ions occupying trans positions in the resulting tetragonally distorted octahedral coordination sphere. Two discrete sets of N-H···Cl hydrogen bonds link the octahedral molecules into a two-dimensional network, with type 1 interactions linking adjacent monomers along the c axis and type 2 interactions linking monomers along the diagonals in the bc plane. Analysis of the magnetic data …

Magnetic molecular metals based on the organic donor molecule BET (BET = Bis(ethylenethio)tetrathiafulvalene): The series BET2[MCI4] (M3⊕= Ga, Fe)

1997

A unique example of structural and magnetic diversity in four interconvertible copper(II)-azide complexes with the same schiff base ligand: a monomer…

2010

Four new Cu(II)-azido complexes of formula [CuL(N(3))] (1), [CuL(N(3))](2) (2), [Cu(7)L(2)(N(3))(12)](n) (3), and [Cu(2)L(dmen)(N(3))(3)](n) (4) (dmen = N,N-dimethylethylenediamine) have been synthesized using the same tridentate Schiff base ligand HL (2-[1-(2-dimethylaminoethylimino)ethyl]phenol, the condensation product of dmen and 2-hydroxyacetophenone). The four compounds have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. Complex 1 is mononuclear, whereas 2 is a single mu-1,1 azido-bridged dinuclear compound. The polymeric compound 3 possesses a 2D structure in which the Cu(II) ions are linked by phenoxo oxygen atoms and t…

Preparation and conductivity of PEDOT encapsulated inside faujasites

2005

Poly[3,4-(ethylenedioxy)thiophene] (PEDOT) encapsulated inside the faujasite micropores has been prepared by polymerization of the monomer in partially Fe-exchanged faujasites. Faujasites containing PEDOT within the interior exhibit notable electrical conductivity compared to plain faujasite. This conductivity is attributed to the presence of polarons that have been detected by EPR spectroscopy.

Molecular hybrids formed by oxalate bridged dinuclear anions and organometallic cations

1999

Abstract The syntheses, magnetic properties and infrared spectra of a new series of molecular hybrids formed by association of two magnetic sublattices: (i) oxalate bridged dinuclear anions [V 2 O 2 (ox)(NCS) 6 ] 4− and [M′M′'(ox)(NCS) 8 ] 4 ( M′= Fe III , Cr III ; M′' - Fe III , Cr III ; ox 2 = C 2 O 4 2 and (ii) decamethylferrocenium organometallic cation are presented. The crystal structure of [Fe(Cp * ) 2 ][(C 2 H 5 ) 4 N] 2 [V 2 O 2 (ox)(NCS) 6 ] is also discussed.

Classical-spin approach to a magnetic comb-like chain: application to the two-sublattice chain compound MnMn(CDTA)·7H2O

1991

Abstract We report on the magnetic properties of the two-sublattice manganese chain MnMn(CDTA)·7H 2 O. In view of the structural features, this compound may give rise to a novel type of one-dimensional magnetic network formed by a chain of exchange coupled triangles. A classical-spin model that considers two magnetic sites coupled through two different and isotropic exchange interactions is developed and used in order to analyze the magnetic properties of this compound. The possibility of having a spinfrustration is also examined.

Magnetochemistry: From Fundamentals to Applications

2016

It is well knowm that Magnetochemistry is a multidisplinary area that deals with many different materials and properties. [...]

(NBu4)Ni(mnt)2: A novel bistable high temperature spin-Peierls-like system

2005

Abstract The title compound, tetrabutylammonium bis(1,2-dimercaptoethene-1,2-dicarbonirtilato-S,S′)-nickel (III) [henceforth (NBu4)Ni(mnt)2] undergoes a hysteretic phase transition that occurs at 172 K upon cooling. Crystallographic studies show that the phase transition is an order–disorder type involving one arm of the NBu 4 + cation. Both phases are monoclinic, space group C2/c with a = 30.860(3), b = 13.804(2), c = 15.678(2) A and β = 115.642(3)° with V = 6020.8(11) A3 at room temperature and with a = 31.073(3), b = 13.928(1), c = 14.414(1) A and β = 115.073(2)° and V = 5652.1(9) A3 at 84 K. In both phases, the anions form non-uniform stacks parallel to the crystallographic c direction.…

Hyperbranched polyethylenimine-supported copper(II) ions as a macroliganted homogenous catalyst for strict click reactions of azides and alkynes in w…

2019

Abstract Loading hyperbranched polyethylenimine (PEI) with copper(II) ions leads to the formation of a new water-soluble metallodendritic polymer Cu(II)-PEI that has been found to effectively catalyze the clickable azide-alkyne [3 + 2] cycloaddition reactions in water under ambient conditions, in the lack of any external reducing agent. A positive dendritic effect on the catalyst activity was observed in the click of 1,2,3-triazole by lowering the reduction potential of copper(II) into the in-situ generation of the catalytically active species copper(I). The reaction proceeds straightforwardly to afford the corresponding 1,4-disubstituted-1,2,3-triazole derivatives in a regioselective manne…

A ferromagnetic methoxido-bridged Mn(III) dimer and a spin-canted metamagnetic μ(1,3)-azido-bridged chain.

2012

Two new Mn(III) complexes of formulas [MnL(1)(N(3))(OMe)](2) (1) and [MnL(2)(N(3))(2)](n) (2) have been synthesized by using two tridentate NNO-donor Schiff base ligands HL(1){(2-[(3-methylaminoethylimino)-methyl]-phenol)} and HL(2) {(2-[1-(2-dimethylaminoethylimino)methyl]phenol)}, respectively. Substitution of the H atom on the secondary amine group of the N-methyldiamine fragment of the Schiff base by a methyl group leads to a drastic structural change from a methoxido-bridged dimer (1) to a single μ(1,3)-azido-bridged 1D helical polymer (2). Both complexes were characterized by single-crystal X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The ma…

Polyoxometalates: From Magnetic Models to Multifunctional Materials

2002

In this article we have presented some recent achievements of the polyoxometalates in the fields of molecular magnetism and functional molecular materials. In the context of the molecular magnetism we have shown that POMs provide ideal examples of magnetic clusters with coexisting ferro and antiferromagnetic exchange interactions which can be investigated using a variety of magnetic techniques, including the Inelastic Neutron Scattering spectroscopy, to get a thorough characterization of the magnetic levels in these large clusters, and to test the validity of the spin hamiltonians commonly used in magnetism.

Synthesis of the first heterometalic star-shaped oxido-bridged MnCu3 complex and its conversion into trinuclear species modulated by pseudohalides (N…

2011

A tetra-nuclear, star-shaped hetero-metallic copper(II)-manganese(II) complex, [{CuL(H(2)O)}(2)(CuL)Mn](ClO(4))(2) (1) has been synthesized by reacting the "complex as ligand" [CuL] with Mn(ClO(4))(2) where H(2)L is the tetradentate di-Schiff base derived from 1,3-propanediamine and 2-hydroxyacetophenone. Upon treatment with the polyatomic anions azide, cyanate, or thiocyanate in methanol medium, complex 1 transforms into the corresponding trinuclear species [(CuL)(2)Mn(N(3))(2)] (2), [(CuL)(2)Mn(NCO)(2)] (3) and [(CuL)(2)Mn(NCS)(2)] (4). All four complexes have been structurally and magnetically characterized. In complex 1 the central Mn(II) ion is encapsulated by three terminal [CuL] unit…

[MnM(egta)]· 8H2O(M= Mn, Cd): A Novel Type of Two-Dimensional Magnetic Lattice

1993

Corrigendum: An Unusually Small Singlet-Triplet Gap in a Quinoidal 1,6-Methano[10]annulene Resulting from Baird's 4n π-Electron Triplet Stabilization.

2016

Within the continuum of π-extended quinoidal electronic structures exist molecules that by design can support open-shell diradical structures. The prevailing molecular design criteria for such structures involve proaromatic nature that evolves aromaticity in open-shell diradical resonance structures. A new diradical species built upon a quinoidal methano[10]annulene unit is synthesized and spectroscopically evaluated. The requisite intersystem crossing in the open-shell structure is accompanied by structural reorganization from a contorted Mobius aromatic-like shape in S0 to a more planar shape in the Huckel aromatic-like T1. This stability was attributed to Baird’s Rule which dictates the …

Polyoxometalate-based metal-organic frameworks for boosting electrochemical capacitor performance

2019

Abstract Polyoxometalate-based metal-organic frameworks (POMOFs) possess promising applications as capacitors. Herein, we report the syntheses, structures and electrochemical properties of five copper-containing POMOFs: [CuI4H2(btx)5(PW12O40)2]·2H2O (1), [CuIICuI3(H2O)2(btx)5(PWVI10WV2O40)]·2H2O (2), [CuI6(btx)6(PWVI9WV3O40)]·2H2O (3), [CuI4H2(btx)5(PMo12O40)2]·2H2O (4) and [CuIICuI3(btx)5(SiMoVI11MoVO40)]·4H2O (5) (btx = 1,4-bis(triazol-1-ylmethyl) benzene) with potential applications as capacitors. Compounds 1–3 contain the same Keggin-type polyoxometalate (POM) although with different oxidation states, allowing the analysis of the effect of the electronic population on the capacitance pe…

Cubane-Type Mo3CoS4 Molecular Clusters with Three Different Metal Electron Populations: Structure, Reactivity and Their Use in the Synthesis of Hybri…

2004

Heterodimetallic cubane-type complexes coordinated to diphosphanes [Mo(3)CoS(4)(dmpe)(3)Cl(4)](+) ([1](+)) (dmpe=1,2-bis(dimethylphosphanyl)ethane), [Mo(3)CoS(4)(dmpe)(3)Cl(4)] (1) and [Mo(3)CoS(4)(dmpe)(3)Cl(3)(CO)] (2) with 14, 15 and 16 metal electrons, respectively, have been prepared from the [Mo(3)S(4)(dmpe)(3)Cl(3)](+) trinuclear precursor using [Co(2)(CO)(8)] or CoCl(2) as cobalt source. Cluster complexes [1](+) and 1 are easily interconverted chemically and electrochemically. The Co-Cl distance increases upon electron addition and substitution of the chlorine atom coordinated to cobalt with CO only takes place in presence of a reducing agent to give complex 2. Structural changes in…

A novel mixed valent Cu(II)-Cu(I) 2D framework made of a hydrazone and μ-SCN bridged metallacyclic loops cross-linked by μ3-SCN chains.

2012

A mixed valent copper complex [Cu(II)Cu(I)(L)(μ-SCN)(μ(3)-SCN)](n) (LH = N'-((pyridin-2-yl)methylene)acetohydrazide) has been synthesized and characterized. It is a unique example of a 2D mixed valent Cu(II)-Cu(I) interlinked molecular assembly with a very unusual bridging property of the hydrazone ligand. An extraordinary in situ partial Cu(II)→ Cu(I) reduction is observed in this system at room temperature.

Macrocycle-Based Spin-Crossover Materials

2009

International audience; New iron(II) complexes of formula [Fe(L1)](BF(4))(2) (1) and [Fe(L2)](BF(4))(2) x H(2)O (2) (L1 = 1,7-bis(2'-pyridylmethyl)-1,4,7,10-tetraazacyclododecane; L2 = 1,8-bis(2'-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) have been synthesized and characterized by infrared spectroscopy, variable-temperature single-crystal X-ray diffraction, and variable-temperature magnetic susceptibility measurements. The crystal structure determinations of 1 and 2 reveal in both cases discrete iron(II) monomeric structures in which the two functionalized tetraazamacrocycles (L1 and L2) act as hexadentate ligands; the iron(II) ions are coordinated with six nitrogen atoms: four from …

Influence of metal ions on the structures of Keggin polyoxometalate-based solids: Hydrothermal syntheses, crystal structures and magnetic properties

2006

Abstract Three new Keggin polyoxometalate (POM)-based compounds linked to 3d metal complexes have been synthesized under hydrothermal conditions: [Cu(phen)2]2{[Cu(phen)]2 [SiMo12O40(VO)2]} (1), {[Zn(phen)2]2[GeMo12O40(VO)2]}{[Zn(phen)2(H2O)]2 [GeMo12O40(VO)2]}·3H2O (2) and {[Co(phen)2]2[PMo12O40(VO)2]}{[Co(phen)2(OH)]2 [PMo12O40(VO)2]}·2.5H2O (3) (phen=1,10-phenanthroline). These three compounds present, as building blocks, the bicapped Keggin anions [XMo12O40(VO)2] (X=Si, Ge and P). Compound 1 consists of a bicapped Keggin anion [SiMo12O40(VO)2]2− linked to two [Cu(phen)]+ complexes with two [Cu(phen)2]+ countercations. Compound 2 contains two bicapped Keggin anions [GeMo12O40(VO)2]4−, one…

Synthesis, structural aspects and magnetic properties of an unusual 2D thiocyanato-bridged cobalt(II)–Schiff base network

2010

Abstract A new two-dimensional (2D) thiocyanato-bridged cobalt(II) network formulated as [LCo2(NCS)2]n (1), has been synthesized with the Schiff base ligand N,N′-bis(3-methoxysalicylidenimino)-1,3-diaminopropane (H2L) and thiocyanate anions. This novel layered compound has been completely characterized by elemental analysis, FT-IR, UV–Vis spectroscopy and the structure has been established by single crystal X-ray diffraction studies. The structure of 1 consists of a doubly phenoxo-bridged dimer comprising two different cobalt(II) centers with different coordination geometries (octahedral and tetrahedral). The 2D network is accomplished by bridging thiocyanate ligands, connecting the dimeric…

Syntheses, structures and magnetic properties of cyano-bridged one-dimensional Ln3+–Fe3+ (Ln = La, Dy, Ho and Yb) coordination polymers

2019

Four new heterometallic one-dimensional coordination polymers with formulae trans-[La(o-phen)3(H2O)(μ-CN)2Fe(CN)4]·7H2O (1) and trans-[Ln(H2O)2(phen)2(μ-CN)2Fe(CN)4]·nH2O [Ln/n = Dy/8 (2), Ho/7 (3) and Yb/7 (4), (o-phen = 1,10-phenanthroline)] have been synthesized by reacting Ln(NO3)3·xH2O with K3[Fe(CN)6] and 1,10-phenanthroline. The structures of 1–4 have been established by single crystal X-ray diffraction. Polymer 1 presents a chain structure with three o-phen ligands coordinated to La3+ and [Fe(CN)6]3− complexes connecting them through two trans CN− ligands to form a linear chain. Compounds 2–4 are solvates and contain Ln3+ ions coordinated to two o-phen ligands and also bridged by [F…

New coordination polymers with a 2,2-dicyano-1-ethoxyethenolate (dcne–) bridging ligand: syntheses, structural characterisation and magnetic properti…

2002

New polymeric materials [M(dcne)2(H2O)2] with M = MnII (1), FeII (2), CoII (3), NiII (4) and ZnII (5) and [Cu(dcne)2(H2O)] (6) (dcne− = [(CN)2CC(O)OEt)]− = 2,2-dicyano-1-ethoxyethenolate anion) have been synthesised and characterised by infrared spectroscopy, X-ray crystallography and magnetic measurements. In these compounds, each organic ligand acts in a bridging mode with its two nitrogen atoms bound to two different metal cations. In compounds 1–5, each metal cation has a pseudo-octahedral cis-MN4O2 environment with four nitrogen atoms from four different organic ligands and two oxygen atoms from two water molecules. In compound 6, only one water molecule is coordinated and each copper(…

Unprecedented layered coordination polymers of dithiolene group 10 metals: Magnetic and electrical properties

2016

One-pot reactions between Ni(ii), Pd(ii) or Pt(ii) salts and 3,6-dichloro-1,2-benzenedithiol (HSC6H2Cl2SH) in KOH medium under argon lead to a series of bis-dithiolene coordination polymers. X-ray analysis shows the presence of a common square planar complex [M(SC6H2Cl2S)2]2- linked to potassium cations forming either a two-dimensional coordination polymer network for {[K2(μ-H2O)2(μ-thf)(thf)2][M(SC6H2Cl2S)2]}n [M = Ni (1) and Pd (2)] or a one-dimensional coordination polymer for {[K2(μ-H2O)2(thf)6][Pt(SC6H2Cl2S)2]}n (3). In 3 the coordination environment of the potassium ions may slightly change leading to the two-dimensional coordination polymer {[K2(μ-H2O)(μ-thf)2][Pt(SC6H2Cl2S)2]}n (4) …

Magnetic Langmuir–Blodgett films of ferritin with different iron loadings

2005

Abstract Magnetic Langmuir–Blodgett multilayers of two ferritin molecules 1 and 2 , containing, respectively, 4220 and 3062 Fe atoms have been prepared by using the adsorption properties of a 6/1 mixed monolayer of dioctadecyldimethylammonium bromide (DODABr) and methyl stearate (SME). Transfer ratios close to unity were reached giving rise to LB films with a strong red colour. Infrared and UV–vis spectroscopy indicates that ferritin molecules are incorporated within the LB films. Magnetic measurements show that the superparamagnetic properties of these molecules are preserved. Thus, a marked hysteresis loop of magnetisation is obtained for LB films of 1 and 2 with a coercive field of 3400 …

(Ni2), (Ni3), and (Ni2 + Ni3): A Unique Example of Isolated and Cocrystallized Ni2 and Ni3 Complexes

2009

Structural and magnetic characterization of compound {[Ni(2)(L)(2)(OAc)(2)][Ni(3)(L)(2)(OAc)(4)]}.2CH(3)CN (3) (HL = the tridentate Schiff base ligand, 2-[(3-methylamino-propylimino)-methyl]-phenol) shows that it is a rare example of a crystal incorporating a dinuclear Ni(II) compound, [Ni(2)(L)(2)(OAc)(2)], and a trinuclear one, [Ni(3)(L)(2)(OAc)(4)]. Even more unusual is the fact that both Ni(II) complexes, [Ni(2)(L)(2)(OAc)(2)] (1) and [Ni(3)(L)(2)(OAc)(4)(H(2)O)(2)].CH(2)Cl(2).2CH(3)OH (2), have also been isolated and structurally and magnetically characterized. The structural analysis reveals that the dimeric complexes [Ni(2)(L)(2)(OAc)(2)] in cocrystal 3 and in compound 1 are almost i…

Diindeno-fusion of an anthracene as a design strategy for stable organic biradicals

2016

The consequence of unpaired electrons in organic molecules has fascinated and confounded chemists for over a century. The study of open-shell molecules has been rekindled in recent years as new synthetic methods, improved spectroscopic techniques and powerful computational tools have been brought to bear on this field. Nonetheless, it is the intrinsic instability of the biradical species that limits the practicality of this research. Here we report the synthesis and characterization of a molecule based on the diindeno[b,i]anthracene framework that exhibits pronounced open-shell character yet possesses remarkable stability. The synthetic route is rapid, efficient and possible on the gram sca…

Synthesis, structure, physicochemical characterization and theoretical evaluation of non-covalent interaction energy of a polymeric copper(II)-hydraz…

2019

Abstract One dimensional polymeric copper-hydrazone complex {[Cu(H0.5L)(µ1,3-SCN)]0.5ClO4·0.5MeOH}n (1) has been synthesized with Cu(ClO4)2·xH2O and N'-(1-(pyridin-2-yl)ethylidene)acetohydrazide (HL) in presence of NaSCN. The ligand and the complex have been characterized by several spectroscopic techniques (IR, UV–Vis and EPR), cyclic voltammetry and the structure of 1 has been determined by single crystal X-ray diffraction. The complex is an infinite one dimensional polymer bridged by thiocyanate. The magneto-structural correlation has been determined and the non-covalent interactions present in the molecule have been energetically evaluated by means of DFT calculations.

Reversible Solvent‐Exchange‐Driven Transformations in Multifunctional Coordination Polymers Based on Copper‐Containing Organosulfur Ligands

2014

The preparation by simple direct synthesis of a series of coordination polymers based on copper with chloride or bromide and dipyrimidinedisulfide is reported. The structural characterisations of these compounds reveal a rich structural variety as a result of the number of coordination modes available to the organosulfur ligand, in combination with the bridging capabilities of the halides. Interestingly, some of the polymers displayed fully reversible solvent exchange/removal crystal-to-crystal 2D to 0D and 2D to 2D transformations. These materials show multifunctional electronic properties. Thus, some of them are semiconductors and present weak antiferromagnetic interactions, and the CuI/C…

A trigonal prismatic anionic iron(iii) complex of a radical o-iminobenzosemiquinonate derivative: structural and spectral analyses

2017

A new iron(III) complex, [Et3NH][FeIII(L2−˙)2] (1) with a substituted o-aminophenol based ligand is reported. Complex 1 is an anionic complex with a triethylammonium cation in the lattice. It contains two O,O,N-coordinated o-iminobenzosemiquinonate(2−) radical anions with an Fe(III) centre in a high-spin configuration. The crystal structure of 1 was determined by X-ray diffraction, which revealed a trigonal prismatic coordination environment whose electronic structure was established by various physical methods including EPR, Mossbauer spectroscopy and variable-temperature (2–300 K) magnetic susceptibility measurements. Electrochemical analysis indicated primarily ligand-centred redox proce…

A two-dimensional radical salt based upon BEDT-TTF and the dimeric, magnetic anion [Fe(tdas)2]22−: (BEDT-TTF)2[Fe(tdas)2] (tdas = 1,2,5-thiadiazole-3…

2002

In an attempt to synthesize new synthetic metals which couple magnetic properties to conductivity, we prepared the novel salt (BEDT-TTF)2[Fe(tdas)2] [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, hereafter referred to as ET; tdas = 1,2,5-thiadiazole-3,4-dithiolate] by the electrocrystallization technique. The crystal structure of this compound, as determined by single crystal X-ray diffraction, contains conducting, organic ET layers separated by dimerized, magnetic [Fe(tdas)2]22− anions. Due to the magnetic insulating ground electronic state of the ET layer, thermally activated conductivity is observed, with a room temperature value of about 1 S cm−1. This salt was also characterized by…

Humidity-Driven Reversible Transformation and Guest Inclusion in a Two-Dimensional Coordination Framework Tailored by Organic Polyamine Cation

2011

Using a polyamine cation tetrenH55+ (tetren = tetraethylenepentaamine), we tailored the dynamic layered material (tetrenH5)1.6{CoII(H2O)2[MIV(CN)8]}4·xH2O (1, M = W, x = 12; 2, M = Mo, x = 11.2). 1 and 2 consist of strongly corrugated two-dimensional (2D) cyano-bridged monolayers {CoII(H2O)2[MIV(CN)8]}n2n– of square grid topology stacked in an alternate manner with cationic layers of tetrenH55+ and H2O molecules. The observed single-crystal-to-single-crystal (SCSC) transformation is due to the reversible dehydration of 1 and 2 to the respective monocrystalline materials (tetrenH5)1.6{CoII[MIV(CN)8]}4 (1deh and 2deh). Structural modifications consist of the change of coordination number (C.N…

Structure and magnetic properties of [(REDA)Cl]2CuCl4 salts: A new series of ferromagnetic layer perovskites

2005

Abstract The preparation, structure and magnetic properties of two mono- N -substituted ethylenediammonium copper chloride salts are reported. Both [(MEDA)Cl] 2 CuCl 4 and [(EEDA)Cl] 2 CuCl 4 assume monoclinic layered perovskite A 2 CuCl 4 type structures (here MEDA 2+ is the N -methylethylenediammonium dication and EEDA 2+ is the N -ethylethylenediammonium dication). In these structures, planar CuCl 4 2 - ions are linked together into layers of corner-sharing distorted octahedra via semi-coordinate Cu⋯Cl bonds. The magnetic studies reveal the presence of dominant ferromagnetic coupling in both compounds and analysis of the higher temperature data yielded J / k  = 19.29(1) K and 19.0(4) K f…

Tetramethyl-Bis(ethylenedithio)-Tetrathiafulvalene (TM-BEDT-TTF) Revisited: Crystal Structures, Chiroptical Properties, Theoretical Calculations, and…

2013

The (S,S,S,S) and (R,R,R,R) enantiomers of tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) show equatorial conformation for the four methyl groups in the solid state, according to the single-crystal X-ray analyses. Theoretical calculations at the Density Functional Theory (DFT) and time-dependent (TD) DFT levels indicate higher gas phase stability for the axial conformer than the equatorial one by 1.25kcal center dot mole-1 and allow the assignment of the UV-vis and circular dichroism transitions. A complete series of radical cation salts of 1:1 stoichiometry with the triiodide anion I3- was obtained by electrocrystallization of both enantiopure and racemic forms of the don…

Two Novel Polyoxometalate-Encapsulated Metal–Organic Nanotube Frameworks as Stable and Highly Efficient Electrocatalysts for Hydrogen Evolution React…

2018

Two novel polyoxometalate (POM)-encapsulated metal–organic nanotube (MONT) framework crystalline materials with unprecedented copper-mixed ligands, HUST-200 and HUST-201, have been successfully synthesized by an effective synthesis strategy. The encapsulation not only provides a shield to increase the chemical stability, but also does not affect its catalytic activity, and, therefore, the crystalline materials are very active for HER (H+ can diffuse easily through the pores of the MONTs). Remarkably, HUST-200 displays a low overpotential of 131 mV (catalytic current density is equal to 10 mA·cm–2). This work thus offers a new way for devising HER electrocatalysts with low cost using POM-enc…

Solvent-modulation of the structure and dimensionality in lanthanoid-anilato coordination polymers.

2018

We show the key role that the size and shape of the solvent molecules may play in the dimensionality and structure of a series of lanthanoid–chloranilato coordination polymers. We report the synthesis, structure and magnetic properties of six different coordination polymers prepared with Er(III) and chloranilato (C6O4Cl22− = 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone) and six different solvents: [Er2(C6O4Cl2)3(H2O)6]·10H2O (1), [Er2(C6O4Cl2)3(FMA)6]·4FMA·2H2O (2) (FMA = formamide = NH2CHO), [Er2(C6O4Cl2)3(DMSO)4]·2DMSO·2H2O (3) (DMSO = dimethy sulfoxide = Me2SO), [Er2(C6O4Cl2)3(DMF)6] (4) (DMF = dimethylformamide = Me2NCHO), [Er2(C6O4Cl2)3(DMA)4] (5) (DMA = dimethylacetamide = Me2NC(Me)O) …

A new BEDT-TTF salt and polypyrrole films containing the chiral polyoxometalate [H4Co2Mo10O38]6−

2005

Abstract The chiral polyoxometalate [H4Co2Mo10O38]6− has been used in the preparation of hybrid materials in the form of crystals or polymeric films. A new radical salt of the donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) containing the two enantiomers of this polyoxometalate has been obtained by electrocrystallization. This radical salt shows semiconducting behavior with room temperature conductivity of 9 S.cm−1 and activation energy of 40 meV. Polypyrrole films doped with a racemic mixture of polyoxometalates and also the enantiomerically pure (+)589-[H4Co2Mo10O38]6− have been prepared electrochemically. Circular dichroism experiments suggest that the chiral polyoxometalate…

Polyoxometalate-Based Molecular Materials.

1998

Molecule-based materials with active physical properties, in particular electrical, magnetic, and optical, are a focus of contemporary materials chemistry research. Certainly, one reason for this interest has been the realization that these materials can exhibit cooperative properties typically associated with the inorganic network solids, as for example metallic conduction or even superconductivity,1 ferromagnetism,2 and nonlinear optical properties.3 With respect to the electrical properties, many important achievements were obtained in the 1970s with the discovery of the first molecule-based metal in 1972,4 namely the π-electron donor-acceptor complex [TTF][TCNQ] (TTF ) tetrathiafulvalen…

Smart composite films of nanometric thickness based on copper-iodine coordination polymers. Toward sensors.

2018

One-pot reactions between CuI and methyl or methyl 2-amino-isonicotinate give rise to the formation of two coordination polymers (CPs) based on double zig-zag Cu2I2 chains. The presence of a NH2 group in the isonicotinate ligand produces different supramolecular interactions affecting the Cu-Cu distances and symmetry of the Cu2I2 chains. These structural variations significantly modulate their physical properties. Thus, both CPs are semiconductors and also show reversible thermo/mechanoluminescence. X-ray diffraction studies carried out under different temperature and pressure conditions in combination with theoretical calculations have been used to rationalize the multi-stimuli-responsive …

Ferromagnetism and Chirality in Two-Dimensional Cyanide-Bridged Bimetallic Compounds

2002

The combination of hexacyanoferrate(III) anions, [Fe(CN)(6)](3)(-), with nickel(II) complexes derived from the chiral ligand trans-cyclohexane-1,2-diamine (trans-chxn) affords the enantiopure layered compounds [Ni(trans-(1S,2S)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (1) and [Ni(trans-(1R,2R)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (2). These chiral systems behave as ferromagnets (T(c) = 13.8 K) with a relatively high coercive field (H(c) = 0.17 T) at 2 K. They also exhibit an unusual magnetic behavior at low temperatures that has been attributed to the dynamics of the magnetic domains in the ordered phase.

Insertion of a single-molecule magnet inside a ferromagnetic lattice based on a 3D bimetallic oxalate network: Towards molecular analogues of permane…

2014

The insertion of the single-molecule magnet (SMM) [MnIII(salen) (H2O)]2 2+ (salen2-=N,N-ethylenebis- (salicylideneiminate)) into a ferromagnetic bimetallic oxalate network affords the hybrid compound [MnIII(salen)(H2O)] 2[MnIICrIII(ox)3] 2×(CH3OH)×(CH3CN)2 (1). This cationic Mn2 cluster templates the growth of crystals formed by an unusual achiral 3D oxalate network. The magnetic properties of this hybrid magnet are compared with those of the analogous compounds [Mn III(salen)(H2O)]2[ZnIICr III(ox)3]2×(CH3OH) ×(CH3CN)2 (2) and [InIII(sal 2-trien)][MnIICrIII(ox)3] ×(H2O)0.25×(CH3OH) 0.25×(CH3CN)0.25 (3), which are used as reference compounds. In 2 it has been shown that the magnetic isolatio…

Rare Example of μ-Nitrito-1κ2O,O′:2κO Coordinating Mode in Copper(II) Nitrite Complexes with Monoanionic Tridentate Schiff Base Ligands: Structure, M…

2008

Three new copper(II) complexes, [CuL(1)(NO(2))](n) (1), [CuL(2)(NO(2))] (2), and [CuL(3)(NO(2))] (3), with three similar tridentate Schiff base ligands [HL(1) = 6-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one, HL(2) = 6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one, and HL(3) = 6-diethylamino-3-methyl-1-phenyl-4-azahex-2-en-1-one] have been synthesized and characterized structurally and magnetically. In all three complexes, the tridentate Schiff base ligand and one oxygen atom of the nitrite ion constitute the equatorial plane around Cu(II), whereas the second oxygen atom of the nitrite ligand coordinates to one of the axial positions. In 1, this axially coordinated oxygen atom of the nitrite …

Influence of the central metal ion in controlling the self-assembly and magnetic properties of 2D coordination polymers derived from [(NiL)2M]2+ node…

2014

Three new 2D coordination polymers (CPs) 2∞[(NiL)2Ni(μ1,5-N(CN)2)2]n (1), 2∞[(NiL)2Cd(μ1,5-N(CN)2)2]n (2) and 2∞[(NiL)2Zn(μ1,5-N(CN)2)2]n (3) have been synthesized by reacting a [NiL] “metalloligand” (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) with three different metal(II) (Ni, Cd and Zn) perchlorates and sodium dicyanamide, with identical molar ratios of the reactants. All three products have been characterized by IR and UV-Vis spectroscopies, elemental analyses, powder and single crystal X-ray diffraction and variable temperature magnetic measurements. The isomorphous compounds 1 and 2 consist of similar [(NiL)2M(μ1,5-N(CN)2)] (M = Ni for 1 and Cd for 2) angular trinuclear un…

Molecular materials based upon organic π-donors and magnetic anions

2000

Electrochemical combination of the magnetic dinuclear anion [MM'(C 2 O 4 )(NCS) 8 ] 4- (MM' = CrCr, CrFe) or paramagnetic mononuclear anion [Cr(NCS) 6 ] 3- with the ET organic π-donor (ET = BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) gives rise to two new series of molecular hybrid salts formulated (ET) 5 [MM'(C 2 O 4 )(NCS) 8 (MM' = CrCr (1), CrFe (2)), (ET) 8 [MM'(C 2 O 4 )(NCS) 8 ] (3), (ET) 5.5 f Cr(NCS) 6 ] (4) and (ET) 5 [(C 2 H 5 ) 4 N] [Cr(NCS) 6 ](THF) (5) (THF = tetrahydrofuran). The crystal structures consist of alternating organic and inorganic layers. The organic part does not produce any detectable effect on the magnetic properties coming from the inorganic sublattice. T…

Polyoxometalates in Langmuir–Blodgett films: toward new magnetic materials

1998

Abstract Polyoxometalates having various structures and properties can be organized by the Langmuir–Blodgett (LB) technique. The adsorption of such polyanions along a positively charged monolayer of DODA (dimethyldioctadecylammonium) induces large changes in the compression isotherm and enables the transfer of the Langmuir film onto solid substrate. X-ray diffraction and infrared dichroism experiments demonstrate that the polyoxometalates are organized in monolayers within the LB films. Furthermore, these magnetic multilayers were characterized by their paramagnetic susceptibility measured by a SQUID magnetometer.

Spin Cross-Over (SCO) Complex Based on Unsymmetrical Functionalized Triazacyclononane Ligand: Structural Characterization and Magnetic Properties

2019

International audience; The unsymmetrical ligand 1-(2-aminophenyl)-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane (L6) has been prepared and characterized by NMR spectroscopy. The L6 ligand is based on the triazamacrocycle (tacn) ring that is functionalized by two flexible 2-pyridylmethyl and one rigid 2-aminophenyl groups. Reaction of this ligand with Fe(ClO4)2·xH2O led to the complex [Fe(L6)](ClO4)2 (1), which was characterized as the first Fe(II) complex based on the unsymmetrical N-functionalized tacn ligand. The crystal structure revealed a discrete monomeric [FeL6]2+ entity in which the unsymmetrical N-functionalized triazacyclononane molecule (L6) acts as hexadentate ligand. As …

Control and Simplicity in the Nanoprocessing of Semiconducting Copper-Iodine Double Chain Coordination Polymers

2018

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.inorgchem.8b00364

Copper(II)–Thymine Coordination Polymer Nanoribbons as Potential Oligonucleotide Nanocarriers

2016

This is the peer reviewed version of the following article: Vegas, V. G., Lorca, R., Latorre, A., Hassanein, K., Gómez‐García, C. J., Castillo, O., ... & Amo‐Ochoa, P. (2017). Copper (II)–Thymine Coordination Polymer Nanoribbons as Potential Oligonucleotide Nanocarriers. Angewandte Chemie International Edition, 56(4), 987-991, which has been published in final form at https://doi.org/10.1002/anie.201609031. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions

High-dimensional mixed-valence copper cyanide complexes: Syntheses, structural characterizations and magnetism

2009

International audience; Reactions of CuCl 2 with different CN complexes in presence of a neutral ancillary ligand lead to two novel mixed-valence Cu complexes [Cu II (bpy)Cu I (CN) 3 ] n , 1 (bpy=2,2′-bipyridine) and {[Cu II (tn) 2 ][Cu I 4 (CN) 6 ]} n 2 (tn=1,3-diaminopropane). For compound 1, the asymmetric unit involves two Cu ions Cu1 and Cu2 (Cu I and Cu II centres, respectively) which strongly differ in their environments. The Cu1 ion presents a CuC 4 pseudo-tetrahedral geometry, while the Cu2 ion presents a CuN 5 slightly distorted square-pyramidal geometry. The extended structure of 1 is generated by three cyano ligands which differ in their coordination modes. One CN group has a μ …

Coordination Polymers Containing Manganese(II)-Azido Layers Connected by Dipyridyl-tetrazine and 4,4′-Azobis(pyridine) Linkers

2013

Two new polynuclear manganese(II) complexes [Mn(dptz)(N(3))(2)](n) (1) and [Mn(azpy)(N(3))(2)](n) (2) (where dptz = dipyridyl-tetrazine and azpy = 4,4'-azobis(pyridine)) have been synthesized by self-assembly of the ligand azide, together with dptz and azpy as secondary spacers. The compounds are characterized by single-crystal X-ray diffraction analyses and variable-temperature magnetic measurements. The structural analyses reveal that in complex 1, which is the first reported Mn(II) complex with the ligand dptz, two μ(1,3) bridging azides connect neighboring manganese ions in a zigzag manner to generate a neutral two-dimensional (2D) sheet which is further connected by the dptz ligands to…

Organic/inorganic molecular conductors based upon perylene and Lindquist-type polyoxometalates

2001

The preparation, structures and physical properties of the organic/inorganic radical salts based upon perylene (per) and Lindquist type polyoxometalates (POMs) are reported. Three new hybrid salts have been prepared: (per)5[Mo6O19] (1), (per)5[W6O19] (2), and (per)5[VW5O19] (3). Only structures 1 (P, Z = 2) and 3 (P, Z = 2) were fully determined as compound 2 was found to have unit cell parameters practically identical to 1 and, therefore, is considered isostructural with the latter. The structures consist of interpenetrated organic and mixed organic/inorganic layers in the ac plane alternating along the a direction. The organic layers present a novel packing mode of the perylene molecules …

Single layers of a multifunctional laminar Cu(I,II) coordination polymer.

2010

A multifunctional bidimensional mixed-valence copper coordination polymer [Cu2Br(IN)2]n (IN = isonicotinato) has been characterized in crystal phase and isolated on graphite surface as single sheets.

Slow Magnetic Relaxation in a Co 2 Dy Trimer and a Co 2 Dy 2 Tetramer

2021

The combination of Co(III) and Dy(III) with a compartmental Schiff base ligand (H 3 L = 3-[(2-Hydroxy-3-methoxy-benzylidene)-amino]-propane-1,2-diol), presenting three different coordinating pockets, has allowed the synthesis of two novel Co(III)-Dy(III) complexes: [Co 2 Dy(HL) 4 ]NO 3 ·2CH 3 CN ( 1 ), a rare example of trinuclear linear Co III 2 Dy III complex (and the first with slow relaxation of magnetization in absence of a DC field) and [Co 2 Dy 2 (μ 3 -OH) 2 (HL) 2 (OAc) 6 ]·4.6H 2 O ( 2 ), the first tetranuclear Co III 2 Dy III 2 cluster with a rhomb-like structure where the Co(III) ions are connected along the short diagonal of the rhomb. 1 presents two different relaxation process…

Restricting Magnetic Interaction Pathways in Polyoxometalate Salts of Cationic Nitronyl Nitroxide Free Radicals

2004

Abstract : Salts 1 and 2 that combine the [W 6 O 19 ] 2- Lindqvist anion with the cationic nitronyl nitroxide (NN) free radicals p -MepyNN + and n Bu 3 NCH 2 NN + , respectively, have been synthesized and their structural and magnetic properties have been studied. Keywords: Nitroxide radicals, polyoxometalates, magnetism. Introduction Ferromagnetism based on purely organic materials has raised a lot of interest during the last decade [1]. Most of the studies have been performed with nitronyl nitroxide (NN) radicals due to their persistence, stability and ease of functionalization [2]. Bulk ferromagnetism in these compounds arises from ferromagnetic interactions between open-shell molecules …

ChemInform Abstract: High Nuclearity Magnetic Clusters: Magnetic Properties of a Nine Cobalt Cluster Encapsulated in a Polyoxometalate, (Co9(OH)3(H2O…

2010

Iron( ii ) and cobalt( ii ) complexes based on anionic phenanthroline-imidazolate ligands: reversible single-crystal-to-single-crystal transformations

2018

A series of low-spin FeII and CoII complexes based on phenanthroline-imidazolate (PIMP) ligands are reported. The FeII complex (H9O4)[Fe(PIMP)3]·(C4H10O)2(H2O) (1a) shows reversible crystalline phase transformations to afford two new phases (H9O4)[Fe(PIMP)3]·(H2O) (1b) and (H9O4)[Fe(PIMP)3]·(C8H18O)(C4H10O)(H2O) (1c) by release of diethyl ether and absorption of diethyl/dibutyl ether, respectively. This reversible uptake/release of solvent molecules is a clear example of single-crystal-to-single-crystal transformation involving a discrete metal complex. On the other hand, the corresponding CoII complex (H9O4)[Co(PIMP)3]·(C4H10O)2(H2O)2 (2) does not exhibit similar phase transformations. In …

Hybrid Molecular Materials Based upon Organic π-Electron Donors and Metal Complexes. Radical Salts of Bis(ethylenethia)tetrathiafulvalene (BET-TTF) w…

2001

The synthesis, structure, and physical characterization of two new radical salts formed with the organic donor bis(ethylenethia)tetrathiafulvalene (BET-TTF) and the octahedral anions hexacyanoferrate(III), [Fe(CN)(6)](3-), and nitroprusside, [Fe(CN)(5)NO](2-), are reported. These salts are (BET-TTF)(4)(NEt(4))(2)[Fe(CN)(6)] (1) (monoclinic space group C2/c with a = 38.867(7) A, b = 8.438(8) A, c = 11.239(6) A, beta = 90.994(9) degrees, V = 3685(4) A(3), Z = 4) and (BET-TTF)(2)[Fe(CN)(5)NO].CH(2)Cl(2) (2) (monoclinic space group C2/c with a = 16.237(6) A, b = 18.097(8) A, c = 12.663(7) A, beta = 106.016(9) degrees, V = 3576(3) A(3), Z = 4). In salt 1 the organic BET-TTF molecules are packed …

Rare examples of diphenoxido-bridged trinuclear Ni II 2 Fe III complexes with a reduced salen type Schiff base ligand: Structures and magnetic proper…

2017

Abstract Three new trinuclear hetero-metallic complexes, [(NiLR)2Fe(N3)3] (1), [(NiLR(H2O))2Fe(C6H5CH2CO2)2]·(HSO4) (2) and [(NiLR(H2O))2Fe(C6H5CO2)2]·(HSO4)·(H2O)·(CH2Cl2) (3) have been synthesized using [NiLR] as a “metalloligand” (where H2LR = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine). All complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD and magnetic study. In the angular trinuclear units of 1, the two terminals [NiLR] coordinate through double phenoxido bridges to the central FeIII ion which is penta-coordinated having terminally coordinated azide ion. The two terminal NiII centers are connected to each other and also to neighbouring…

Designing dicyanamide bridged 1D molecular architecture from a mononuclear copper(II) Schiff base precursor: Syntheses, structural variations and mag…

2009

International audience; A new tridentate N2O donor Schiff base ligand [(C6H5C(OH)CHC(CH3)NCH2C5H4N)LH] was obtained by 1:1 condensation of benzoylacetone with 2-picolylamine and has been used to synthesise a mononuclear [CuLCl] (1) and an end-to-end dicyanamide bridged polynuclear {[Cu2(μ-L)2(μ2-1,5-(CN)2N)]ClO4}n (2) copper(II) complexes. The ligand, 1 and 2 were clearly characterised by elemental analysis, FT-IR, 1H NMR, UV–Vis spectral studies, electrochemical studies and in addition single crystal X-ray diffraction studies were performed for 1 and 2. The Schiff base ligand [LH] shows a significant variation in its coordination behaviour with copper(II) ion in absence and in presence of …

Ring opening polymerization of d,l-lactide and ε-caprolactone catalysed by (pyrazol-1-yl)copper(ii) carboxylate complexes

2021

1,2-Bis{(3,5-dimethylpyrazol-1-yl)methyl}benzene (L) reacts with [Cu(OAc)2] and C6H5COOH, 4-OH-C6H4COOH, 2-Cl-C6H4COOH and (3,5-NO2)2-C6H3COOH to afford the copper complexes [Cu2(C6H5COO)4(L)2] (1), [Cu2(4-OH-C6H4COO)4(L)2] (2), [Cu2(2-Cl-C6H4COO)4(L)2]n (3) and [Cu{(3,5-NO2)2-C6H3COO}2L]n (4) which are characterised by IR, mass spectrometry, elemental analyses, and X-ray crystallography. The structural data revealed two geometries that are adopted by the complexes: (i) paddle wheel in 1, 2·7H2O, 3 and (ii) regular chains in 3 and 4. Magnetic studies show strong antiferromagnetic couplings in the paddle wheel complexes and a weak antiferromagnetic coupling in the monometallic chain one. Cat…

A rare example of nickel(ii) chains based on a heteroscorpionate-like ligand with quadruple imidazolyl interactions

2014

The first nickel(ii) complex with the heteroscorpionate-like bridging ligand DIMMAL (2-di1H-2-imidazolylmethylmalonate), [Ni(DIMMAL)(H2O)3]n·3nH2O (1), is a one-dimensional coordination polymer whose structure shows regular Ni(ii) chains with H-bonding inter-chain interactions and a rare example of a Quadruple Imidazolyl Embrace (QIE). The Ni(ii) chain shows a weak antiferromagnetic interaction that can be modelled with a regular S = 1 chain model including a zero field splitting with g = 2.270, J = -1.5 cm(-1) and D = -2.26 cm(-1).

Back Cover: Electrical Conductivity and Strong Luminescence in Copper Iodide Double Chains with Isonicotinato Derivatives (Chem. Eur. J. 48/2015)

2015

New Multidimensional Coordination Polymers with μ 2 ‐ and μ 3 ‐dcno Cyano Carbanion Ligand {dcno – = [(NC) 2 CC(O)O(CH 2 ) 2 OH] – }

2006

New polymeric materials [M(dcno)2(H2O)2] [M = FeII (1), CoII (2)] and [M(dcno)2] [M = CuII (3), MnII (4)] with dcno– =[(NC)2CC(O)O(CH2)2OH]– = 2,2-dicyano-1-(2-hydroxyethoxy)ethenolate anion have been synthesised and characterised by IR spectroscopy, X-ray crystallography and magnetic measurements. In compounds 1 and 2, each organic ligand acts in a bridging mode with its two nitrogen atoms bound to two different metal ions, while in compounds 3 and 4, each organic anion acts as a μ3-bridging ligand through its two nitrogen atoms and the oxygen atom of the OH group. Each metal ion has a pseudo-octahedral trans-MN4O2 environment with four nitrogen atoms from four different organic ligands an…

High-nuclearity magnetic clusters: Magnetic interactions in clusters encapsulated by molecular metal oxides

1995

Abstract The ability of the molecular metal oxides derived from the Keggin anion [PW 12 O 40 ] 3− to accommodate magnetic ions at specific sites, giving rise to polymetallic clusters with increasing spin nuclearities is discussed. Examples of magnetic clusters with three, four and nine metal ions exhibiting ferromagnetic exchange couplings or a coexistence of ferro- and antiferromagnetic couplings are reported.

Intercalation of cobalt(II)-tetraphenylporphine tetrasulfonate complex in magnetic NiFe-layered double hydroxide

2013

Abstract Hybrid magnetic multilayers have been synthesized by means of intercalation of [5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato]cobalt(II) (CoTPPS) complex in the interlayer space of a Ni II Fe III layered double hydroxide (LDH), through anion-exchange reaction. A sebacate ( − OOC–(CH 2 ) 8 –COO − ) intercalated NiFe-LDH have been used as precursor, facilitating the anion exchange reaction, thus permitting the inclusion of a paramagnetic macrocycle inside the ferrimagnetic NiFe-LDH layers. The material has been characterized by XRD, FT-IR, SEM, SQUID and ESR. The T c for the hybrid NiFe–CoTPPS, ca. 11–12 K, is very close to that shown by the precursor, despite that the intercala…

First tetrathiafulvalene (TTF) cation-radical salt containing the inorganic polyoxometalate β-[Mo8O26]4⊖

1993

Long-term ozone exposure of potato: Free radical content and leaf injury analysed by Q-band ESR spectroscopy and image analysis

2008

This paper presents Q-band electron spin resonance (ESR) studies on free radicals (FR) generated in potato leaves exposed to different O(3) levels in open-top chambers (OTC), together with a quantitative study of the relationship between FR signal intensity and area of potato leaf damage. The advantages of Q-band when compared to X-band ESR spectroscopy are analysed, the main advantage being an absence of overlapping between Mn(II) and FR signals, allowing a quantitative study of FR signal intensity. This study also reports on a graphical method developed to quantitatively measure the damaged area on leaves caused by ozone exposure. Results indicate a direct relationship between FR signal i…

Scanning tunnelling spectroscopy study of paramagnetic superconducting β''-ET(4)[(H(3)O)Fe(C(2)O(4))(3)]·C(6)H(5)Br crystals.

2010

Scanning tunnelling spectroscopy (STS) and microscopy (STM) were performed on the paramagnetic molecular superconductor β''-ET(4)[(H(3)O)Fe(C(2)O(4))(3)]·C(6)H(5)Br. Under ambient pressure, this compound is located near the boundary separating superconducting and insulating phases of the phase diagram. In spite of a strongly reduced critical temperature T(c) (T(c) = 4.0 K at the onset, zero resistance at T(c) = 0.5 K), the low temperature STS spectra taken in the superconducting regions show strong similarities with the higher T(c) ET κ-derivatives series. We exploited different models for the density of states (DOS), with conventional and unconventional order parameters to take into accoun…

Bimetallic cyanide-bridged complexes based on the photochromic nitroprusside anion and paramagnetic metal complexes

2001

Abstract Three novel compounds formed by the photochromic nitroprusside anion, [Fe(CN)5NO]2−, and the paramagnetic complexes [Cu(C19H18N6)]2+, [Ni(C6H14N2)2]2+ and [Ni(cyclam)]2+ are reported. The structure of [Cu(C19H18N6)][Fe(CN)5NO] (1) comprises binuclear complexes with a [Fe(CN)5NO]2− anion linked to a [Cu(C19H18N6)]2+ cation. The structure of [Ni(C6H14N2)2][Fe(CN)5NO]·6.5H2O (2) and [Ni(cyclam)][Fe(CN)5NO]·4H2O (3) consists of zigzag chains formed by an alternate array of the paramagnetic cations and [Fe(CN)5NO]2− anions. The three compounds are paramagnets; a fourth compound containing [cis-Ni(en)2]2+ cations and [Fe(CN)5NO]− anions does not show a change in the magnetic properties a…

Synthesis and characterisation of polymeric metal-ion carboxylates from benzene-1,3,5-tricarboxylic acid with Mn(II), Co(II) or Zn(II) and 2,2-bipyri…

2001

A total of 13 new co-ordination solids have been prepared of composition [Co(HBTC)(PHEN)(H2O)] (12), [Mn-3(BTC)(2)(PHEN)(3)] (13), [Mn(HBTC)(6)(H2O)] (14), [Mn(HBTC)(7)(H2O)] (15), [Zn-3(BTC)(2)(6)(3)(H2O)(3)]. 4H(2)O (16), [Zn-(HBTC)(6)(H2O)] (17), [Zn(H2BTC)(2)(6)] (18), [Zn(HBTC)(7)(H2O)] (19), [Zn(HBTC)(8)(H2O)] (20), [Zn-2(HBTC)(2)(9)(2)]. 2H(2)O (21), [Zn(HBTC)(10)(H2O)].H2O (22), [Co(HBTC)(10)(H2O)].H2O (23) and [Co(HBTC)(11)(H2O)] (24) 6 = pyridine-2-(1-methyl-1H-pyrazol-3-yl); 7 = pyridine-2-(1-methyl-4-bromo-1H-pyrazol-3-yl); 8 = pyridine-2-(1-methyl-4-nitro-1H-pyrazol-3-yl); 9 = pyridine-2-(1-methyl-5-trifluoromethyl-1H-pyrazol-3-yl); 10 = pyridine-2-(1-methyl-5-tert-butyl-1H-pyr…

Synthesis, structure and magnetic characterization of a dinuclear and two mononuclear iron(III) complexes with N,O-donor Schiff base ligands

2018

Abstract One centrosymmetric dinuclear and two mononuclear iron(III) Schiff base complexes, [(µ-OMe)2Fe2(L1)2(N3)2] (1) {HL1 = 2-((2-(dimethylamino)ethylimino)methyl)-6-ethoxyphenol}, [FeL2(OH2)(N3)]·CH3OH (2) {H2L2 = N,N′-bis(3-ethoxysalicylidene)propane-1,3-diamine} and [FeL3(OH2)(NCS)]·2H2O (3) {H2L3 = N,N′-bis(3-methoxysalicylidene)propane-1,3-diamine}, have been synthesized and characterized by elemental analysis and spectral studies. X-ray diffraction analysis was used to determine the structures of all three complexes. Variable temperature (2–300 K) magnetic susceptibility (χ) data of complex 1 show that both iron(III) centres in the complex are in a high spin configuration (S = 5/2)…

A rare case of solution and solid state inter-conversion of two copper(II) dimers and a copper(II) chain

2011

Abstract Three Cu(II)-azido complexes of formula [Cu2L2(N3)2] (1), [Cu2L2(N3)2]·H2O (2) and [CuL(N3)]n (3) have been synthesized using the same tridentate Schiff base ligand HL (2-[(3-methylaminopropylimino)-methyl]-phenol), the condensation product of N-methyl-1,3-propanediamine and salicyldehyde). Compounds 1 and 2 are basal-apical μ-1,1 double azido bridged dimers. The dimeric structure of 1 is centrosymmetric but that of 2 is non-centrommetric. Compound 3 is a μ-1,1 single azido bridged 1D chain. The three complexes interconvert in solution and can be obtained in pure form by carefully controlling the synthetic conditions. Compound 2 undergoes an irreversible transformation to 1 upon de…

A ferromagnetically coupled single hydroxido bridged tetranuclear nickel(II) Schiff base complex incorporating a Ni4O4 cubane core: Crystal structure…

2013

Abstract The new tetranuclear nickel(II) complex [Ni4(OH)(L)(HL)2(CH3OH)1.5(H2O)1.5]·9H2O (1) has been synthesised by the reaction of NiCl2·6H2O and the Schiff base ligand H3L (H3L = (CH3O)(OH)C6H3CH N–C(CH3)(CH2OH)2), prepared by the 1:1 condensation of 2-amino-2-methyl-1,3-propanediol and o-vanillin, and characterized by different physicochemical methods. Single crystal X-ray structural determination identifies a Ni4O4 cubane moiety as the central part of the complex unit. The presence of a single μ3-hydroxido bridged oxygen occupying only one vertex of the Ni4O4 cubane core is rare in Ni4O4 cubanes (ca. 5% of occurrence). Structural analysis also reveals two similar alkoxido oxygen atoms…

Coexistence of ferromagnetism and metallic conductivity in a molecule-based layered compound

2000

Crystal engineering--the planning and construction of crystalline supramolecular architectures from modular building blocks--permits the rational design of functional molecular materials that exhibit technologically useful behaviour such as conductivity and superconductivity, ferromagnetism and nonlinear optical properties. Because the presence of two cooperative properties in the same crystal lattice might result in new physical phenomena and novel applications, a particularly attractive goal is the design of molecular materials with two properties that are difficult or impossible to combine in a conventional inorganic solid with a continuous lattice. A promising strategy for creating this…

Polypyridyl-based Cu(II) coordination polymers: Synthesis, structural and magnetic characterizations

2015

Abstract New Cu(II) coordination polymeric neutral chains of formula [Cu 2 (1,4-tpbd)Cl 2 L 2 ] (1,4-tpbd =  N,N,N ′ N ′-tetrakis(2-pyridylmethyl)benzene-1,4-diamine, L = 1,1,3,3-tetracyano-2-ethoxypropenide (tcnoet) − ( 1) or 1,1,3,3-tetracyano-2-propoxypropenide (tcnopr) − ( 2 )) have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. The crystal structure determinations of 1 and 2 reveal in both cases a one-dimensional structure in which the 1,4-tpbd acts as a bis-chelating ligand and the two chloride anions as asymmetrical bridging ligands. The Cu⋯Cu distances through the bis-chelating 1,4-tpbd ligand (8.194(1) and 8.245(3) A for 1 …

Innentitelbild: An Unusually Small Singlet-Triplet Gap in a Quinoidal 1,6-Methano[10]annulene Resulting from Baird’s 4nπ-Electron Triplet Stabilizati…

2015

Radical cation salts based on BEDT-TTF and the paramagnetic anion [Cr(NCS)6]3−

1999

Abstract A new radical cation salt formulated as (ET)5.5[Cr(NCS)6] (ET = BEDT-TTF = bis(ethylene)dithiotetrathiafulvalene) has been synthesised and characterised by X-ray diffraction and magnetic measurements. The structure shows the presence of alternating layers of the ET units and mixed layers of anions and an isolated ET molecule. The magnetic susceptibility data in the temperature range 2–300 K show a Curie law with C = 1.771 cm3.K.mol−1 and Nα = 1.20.10−5 cm3.mol−1, in agreement with the presence of isolated Cr(III) without any contribution from the organic part.

New planar polynitrile dianion and its first coordination polymer with unexpected short M⋯M contacts (tcno2−=[(NC)2CC(O)C(CN)2]2−)

2008

International audience; A new planar polynitrile dianion ([tcno]2− = [(NC)2CC(O)C(CN)2]2−) has been synthesized as its potassium salt, K2[tcno] (1). The crystallization of 1 by the slow evaporation of an aqueous solution at room temperature gave two types of colourless crystals having two different shapes [1-A: fine plates and 1-B: needles] for which the crystal structure determinations showed similar geometries for the polynitrile anion in both the structures. The combination of this novel dianion with Cu(II) led to the coordination complex [Cu(tcno)2(H2O)2] (2), which constitutes the first coordination complex of this dianion. The structure of 2 can be described as a coordination polymer …

Novel mixed-valence Cu compounds formed by Cu(II) dimers with double oximato bridges: in situ formation of anionic layer [Cu2(SCN)3]n(n-).

2013

Two new N3O donor ketoxime Schiff bases (HL(1) and HL(2)) have been synthesized by condensing N,N-dimethylethylenediamine with diacetylmonoxime and benzilmonoxime, respectively in a 1:1 ratio. Reaction of Cu(ClO4)2·6H2O with HL(1) resulted in a discrete oximato-bridged dinuclear Cu(II) complex [Cu2(L(1))2(H2O)2](ClO4)2 (1). The same reaction in presence of NaSCN affords the complex {[Cu(II)2(L(1))2][Cu(I)4(μ(1,3)-SCN)4(μ(1,1,3)-SCN)2]}n (2), where partial Cu(II)→Cu(I) reduction is observed. In 2, arrays of [Cu(II)2(L(1))2](2+) cationic units are inserted in between 2D {[Cu(I)4(SCN)6](2-)}n layers and connected via μ(1,1,3)-SCN(-) links, thus forming a 3D network. On the other hand, reaction…

Unusual packing of ET molecules caused by π–π stacking interactions with TRISPHAT molecules in two [ET][TRISPHAT] salts (ET=bis(ethylenedithio)tetrat…

2007

Abstract The synthesis, structure and physical properties of two new radical salts formed with the organic donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) and a racemic mixture of the chiral anion (tris(tetrachlorobenzenediolato)phosphate(V)) (TRISPHAT) are reported. The structure of the salts (ET)4[TRISPHAT]4 · 3.5H2O (1) and (ET)(TRISPHAT) · CH2Cl2 · CH3CN (2) has been solved by X-ray single crystal diffraction. Unusual packings of ET molecules are obtained in the two structures. The electrical properties indicate that both compounds are insulators. This is in agreement with the isolation of the ET molecules and their complete ionization. On the other hand, the anisotropy of …

A novel oxovanadate structural type – Synthesis, single crystal structure and magnetic properties of a mixed-valence polyoxovanadate formed by {V17O4…

2007

Abstract A novel polyoxovanadate structural type, with an average nuclearity of V16, formed by a mixture of two different polyoxovananadates: {V15O36(Cl)} and{V17O40(Cl)} has been synthesized and characterized. The title compound, formulated as [Ni(phen)3]2{[V15O36(Cl)]0.5[V17O40(Cl)]0.5} · H2O (1) (phen = 1,10′-phenanthroline), presents two different polyoxovanadate architectures: {V15O36(Cl)} and {V17O40(Cl)}, with the last one representing a new framework type in polyoxovanadate chemistry. Here, we present the synthesis of this novel polyoxovanadate under hydrothermal conditions and its characterization by IR and XPS spectroscopies, elemental and thermogravimetric analysis, redox titrati…

Structural re-arrangement in two hexanuclear CuIIcomplexes: from a spin frustrated trigonal prism to a strongly coupled antiferromagnetic soluble rin…

2014

The addition of water to a chloroform solution of the Cu6 trigonal prism complex [Cu6(μ6F)(μ2OH)(μ3OCH3)2(μ2OCH3)2(3,5-Me2pz)6] (1) (3,5-Me2pz− = 3,5-dimethylpyrazolate) results in the formation of the Cu6 planar hexagonal ring complex [Cu6(μ2OH)6(3,5-Me2pz)6]·CH3CN·CHCl3 (2). A simple mechanism for this structural re-arrangement is proposed, in which 2 can be viewed as a hydrolysis product of 1. This process is clearly noticeable in the magnetic properties, which change from spin frustrated with a weak antiferromagnetic coupling in 1, to strongly antiferromagnetic in 2. Interestingly, the hexagonal ring complex 2 self-assembles in the solid state to form a porous hexagonal tubular structur…

Electrical Conductivity and Luminescence in Coordination Polymers Based on Copper(I)-Halides and Sulfur-Pyrimidine Ligands

2011

The solvothermal reactions between pyrimidinedisulfide (pym(2)S(2)) and CuI or CuBr(2) in CH(2)Cl(2):CH(3)CN lead to the formation of [Cu(11)I(7)(pymS)(4)](n) (pymSH = pyrimidine-2(1H)-thione) (1) and the dimer [Cu(II)(μ-Br)(Br)L](2) (L = 2-(pyrimidin-2-ylamino)-1,3-thiazole-4-carbaldehyde) (2). In the later reaction, there is an in situ S-S, S-C(sp(2)), and C(sp(2))-N multiple bond cleavage of the pyrimidinedisulfide resulting in the formation of 2-(pyrimidin-2-ylamino)-1,3-thiazole-4-carbaldehyde. Interestingly, similar reactions carried out just with a change in the solvent (H(2)O:CH(3)CN instead of CH(2)Cl(2):CH(3)CN) give rise to the formation of coordination polymers with rather diffe…

Nanosheets of Two-Dimensional Magnetic and Conducting Fe(II)/Fe(III) Mixed-Valence Metal-Organic Frameworks.

2017

We report the synthesis, magnetic properties, electrical conductivity, and delamination into thin nanosheets of two anilato-based Fe(II)/Fe(III) mixed-valence two-dimensional metal–organic frameworks (MOFs). Compounds [(H3O)(H2O)(phenazine)3][FeIIFeIII(C6O4X2)3]·12H2O [X = Cl (1) and Br (2)] present a honeycomb layered structure with an eclipsed packing that generates hexagonal channels containing the water molecules. Both compounds show ferrimagnetic ordering at ca. 2 K coexisting with electrical conductivity (with room temperature conductivities of 0.03 and 0.003 S/cm). Changing the X group from Cl to Br leads to a decrease in the ordering temperature and room temperature conductivity tha…

Chiral Molecular Magnets: Synthesis, Structure, and Magnetic Behavior of the Series [M(L-tart)] (M = MnII, FeII, CoII, NiII;L-tart = (2R,3R)-(+)-tart…

2006

A new series of layered magnets with the formula [M(L-tartrate)] (M = Mn(II), Co(II), Fe(II), Ni(II); L-tartrate = (2R,3R)-(+)-tartrate) has been prepared. All of these compounds are isostructural and crystallize in the chiral orthorhombic space group I222, as found by X-ray structure analysis. Their structure consists of a three-dimensional polymeric network in which each metal shows distorted octahedral coordination bound to four L-tartrate ligands, two of which chelate through an alcohol and a carboxylate group and the other two bind terminally through a monodentate carboxylate group. The chirality of the ligand imposes a Delta conformation on all metal centers. Magnetically, the paramag…

A stable oxoverdazyl free radical: Structural and magnetic characterization

2006

Abstract The structure and magnetic properties (susceptibility and ESR) of the stable oxoverdazyl free radical 6-(4-acetamidophenyl)-1,4,5,6-tetrahydro-2,4-dimethyl-1,2,4,5-tetrazin-3(2H)-one are presented. The crystal structure consists of chains of parallel planar molecules running along the b-axis. These chains are formed by dimers with a ring-over-bond overlap and a significant offset between dimers, although with similar inter- and intradimer distances. The susceptibility measurements show that this compound is an S = 1/2 paramagnet with weak antiferromagnetic interactions. The magnetic susceptibility can be very well reproduced with an antiferromagnetic regular chain model with g = 2.…

A fluorescent layered oxalato-based canted antiferromagnet

2018

We report the synthesis and characterization of the first fluorescent oxalato-based canted antiferromagnet. Compound [DOC][MnFe(C2O4)3] (1) (DOC = 3,3'-diethyloxacarbocyanine) combines the well-known canted antiferromagnetic [MnFe(C2O4)3]- honeycomb layers with a fluorescent cationic cyanine-type fluorescent dye. Besides the expected spin canted antiferromagnetic order in the oxalato layer at ca. 29 K, we show the key role played by the anionic oxalato lattice in the optical properties of the cation since it provides isolation of dye cations in the hexagonal cavities of the oxalato-based matrix. The emission of the DOC+ dye shows a redshift and a broadening of the emission as well as an inc…

Homo and heterometallic rhomb-like Ni4 and Mn2Ni2 complexes

2014

Abstract Two new polynuclear complexes with hydroxyl-rich Schiff base ligand 3-[(2-Hydroxy-benzylidene)-amino]-propane-1,2-diol (H3L), namely [NiII2(HL)(H2L)(SCN)]2·DMF (1) and [MnIII2NiII2(HL)2(L)2] (2) have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, FTIR, UV–Vis spectroscopy and variable temperature magnetic susceptibility measurements. The X-ray refinements reveal that both compounds present defective rhomb-like dicubane central cores (Ni4 in 1 and Mn2Ni2 in 2). Magnetic susceptibility measurements indicate the presence of overall antiferromagnetic exchange interactions in 1 along the side connected by a N and O atoms (J1 = −43.6 cm−1) and…

On the Road to MM′X Polymers: Redox Properties of Heterometallic Ni···Pt Paddlewheel Complexes

2014

On the quest of heterometallic mixed-valence MM'X chains, we have prepared two stable discrete bimetallic compounds: the reduced (PPN)[ClNi(μ-OSCPh)4Pt] (PPN = bis(triphenylphosphine)iminium; OSCPh = benzothiocarboxylato) and the oxidized [(H2O)Ni(μ-OSCPh)4PtCl] species. The role of the aqua and chlorido axial ligands is crucial to facilitate oxidation of the {Ni(μ-OSCPh)4Pt} core. Experimental and theoretical analyses indicate that a NiPt-Cl/Cl-NiPt isomerization process occurs in the oxidized species. The electronic structure of the reduced system shows two unpaired electrons, one located in a d(x(2)-y(2)) orbital of the Ni(II) ion and a second in the antibonding d(z(2)-dz(2)) combination…

Structure and Magnetic Properties of the Ferromagnetic Cu3Cl126- Trimer in [(NH3C2H4)3NH]2Cu3Cl14

2004

The crystal structure consists of a strongly hydrogen bonded network of tris(N-ethylammonium)ammonium cations, Cu3Cl12(6)- trimeric species, and Cl- anions. The Cu3Cl12(6)- trimers are formed by two distorted tetrahedral CuCl4(2)- anions linked to a central square planar CuCl4(2)- anion via semicoordinate Cu-Cl...Cu mu1 bridges. The central copper ion shows only small deviations from ideal D4h symmetry, while the terminal copper ions show a mild distortion from D2d symmetry with an average trans Cl-Cu-Cl angle of 136.0 degrees. The semicoordinate linkages provide a ferromagnetic exchange pathway between the copper ions with J/k = 6.91(3) K. Short Cl...Cl contacts (3.67-3.90 angstoms) lead t…

Electrical Bistability around Room Temperature in an Unprecedented One-Dimensional Coordination Magnetic Polymer

2013

The synthesis, crystal structure, and physical properties of an unprecedented one-dimensional (1D) coordination polymer containing [Fe2(S2C6H2Cl2)4](2-) entities bridged by dicationic [K2(μ-H2O)2(THF)4](2+) units are described. The magnetic properties show that the title compound presents pairwise Fe-Fe antiferromagnetic interactions that can be well reproduced with a S = 1/2 dimer model with an exchange coupling, J = -23 cm(-1). The electrical conductivity measurements show that the title compound is a semiconductor with an activation energy of about 290 meV and two different transitions, both with large hysteresis of about 60 and 30 K at 260-320 K and 350-380 K, respectively. These two tr…

Solvent Modulated Assembly of Two Ni(II) Complexes: Syntheses, Structures and Magnetic Properties

2016

A dinuclear [Ni2(L)2(DMSO)2(MeOH)2] (1) and a tetra-nuclear [Ni4(L)4(DMF)2(H2O)2].DMF (2) Ni(II) complexes have been prepared by treating nickel nitrate hexahydrate with the Schiff base ligand H2L (H2L=(E)-2-(2-hydroxybenzyliden)amino-4-nitrophenol) in a one-pot reaction. Complex 1 was obtained after recrystallization of the precipitate from the reaction with a 1:1:1 mixture of DMSO/CH2Cl2/MeOH. In contrast, the tetrameric complex 2 was obtained after slow evaporation of the filtrate. Both complexes were characterized by analytical, thermogravimetric, optical and magnetic techniques. The solid state molecular structures of 1 and 2 were determined by single crystal X-ray crystallography. Com…

Enantioselective epoxidation of olefins with molecular oxygen catalyzed by gold(III): A dual pathway for oxygen transfer

2009

Abstract A chiral gold(III) complex has been prepared that performs the epoxidation of olefins in the presence of O 2 , PhIO, or bleach. Catalytic experiments with 18 O show that O 2 is activated on the catalyst and can be directly incorporated into the epoxide through a non-radical mechanism that probably involves formation of gold, oxo, or peroxo species. In addition to this, there is a parallel radical mechanism operating that yields α , β -unsaturated ketones and alcohols as subproducts. Electrochemical and UV–Vis experiments confirmed the occurrence of a Au(III)/Au(I) redox cycle during the catalytic epoxidation in a mechanism sustained by molecular oxygen.

Reversible switching of the electronic ground state in a pentacoordinated Cu(ii) complex.

2013

International audience; An easy reversible switching of the electronic ground state in a pentacoordinated copper(ii) complex is reported for the first time. The simple protonation of a carboxylic group in a Cu(ii) complex with a {dx(2)-y(2)}(1) electronic configuration leads to a flip of the ground electronic configuration from {dx(2)-y(2)}(1) to {dz(2)}(1) in the metal ion.

Switching and redox isomerism in first-row transition metal complexes containing redox active Schiff base ligands.

2014

International audience; The reversible redox isomerisms in first row transition metal complexes of the type ML2 were studied. The six ML2 complexes (M = Mn(III) (), Fe(II) (), Co(III) (), Ni(II) (), Cu(II) () and Zn(II) ()) were synthesized with a redox active Schiff base ligand [2-(3,5-di-tert-butyl-2-hydroxyphenylamino)-4-chlorophenol] (H3L) presenting different oxidation states from -2 to 0 (L(2-), L(-) and L(0)). EPR spectra and magnetic susceptibility measurements indicate the presence of complexes of the type [Mn(III)(L(2-))(L(-))] () with S = 1/2, [Fe(II)(L(-))2] () with S = 2, [Co(III)(L(2-))(L(-))] () with S = 1/2, [Ni(II)(L(-))2] () with S = 1, [Cu(II)(L(-))2] () with S = 1/2 and …

New conducting radical salts based upon Keggin-type polyoxometalates and perylene

2004

Three new radical salts, Per6[PMo12O40]·CH2Cl2 (1), Per6[PMo12O40]·CH3CN (2), and Per9(NBu4)4[SiW12O40]2 (3) (Per = perylene), have been synthesised and their electrical and magnetic properties characterised. These three salts are diamagnetic and they behave as semiconductors with room temperature conductivities of 69, 3.6 and 0.85 S cm−1. While salt 2 presents hole-type conduction and 3 exhibits electron-dominated electrical transport properties, salt 1 shows at 150 K an abrupt change in the thermal dependence of the electrical conductivity and the Seebeck coefficient suggesting a phase transition.

Hepta- and tetra-nuclear copper(II) clusters self-assembled by cyano- and azacyano-carbanions

2015

International audience; Two polynuclear copper(II) complexes with hydroxido-bridging ligands and polycyanide units, [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2](tcm)4Cl2·2H2O (1) and [{Cu(bpy)}4(OH)4(dca)2](dca)2·bpy·2H2O (2) (tn = NH2(CH2)3NH2; tcm− = [C(CN)3]−, bpy = 2,2′-bipyridyl, dca− = [N(CN)2]−) have been prepared by one-pot reactions. The structure of 1 consists of a centrosymmetric heptanuclear ion [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2]6+. The tcm− and the halide anions which appear as counter-ions in the formula unit, play an important role in the stabilization of the complex since the hydrogen bonding between nitrogen atoms of the tcm− anion and halide anions, and hydrogen atoms of the terminal wa…

Tuning the magnetic properties in the layered molecular based magnets A[FeIIRuxIIIM1−xIII(ox)3] (MIII=Cr or Fe; ox=oxalate; A=organic or organometall…

2001

Abstract The magnetic properties of the family of layered molecular magnets A[FeIIMIII(ox)3] (MIII=Cr, Fe, Ru; ox=oxalate; A+=[NBu4]+, [ CoCp 2 ∗ ] + ) are reported. In particular, a detailed magnetic study of the solid solutions FeII(RuIIICrIII) and FeII(RuIIIFeIII) has been undertaken. We show that in these magnets both, transition temperatures and coercive fields, can be easily tuned by changing the chemical composition of the material, i.e. the ratio RuIII/MIII (MIII=Cr, Fe) within the magnetic layers and the type of cation A+ inserted in between the layers. Coercive fields as high as 2.2 T have been reached in this way.

Polynitrile anions as ligands: From magnetic polymeric architectures to spin crossover materials

2010

International audience; The use of polynitrile anions as ligands (L) either alone or in combination with neutral co-ligands (L′) is a very promising and appealing strategy to get molecular architectures with different topologies and dimensionalities thanks to their ability to coordinate and bridge metal ions in many different ways. The presence of several potentially coordinating nitrile groups (or even other donor groups as –OH, –SH or –NH2), their rigidity and their electronic delocalization allow the synthesis of original magnetic high dimensional coordination polymers with transition metals ions. Furthermore, these ligands have shown coordinating and bridging capabilities in novel discr…

Molecular conductors based on the mixed-valence polyoxometalates [SMo12O40]n- (n = 3 and 4) and the organic donors bis(ethylenedithio)tetrathiafulval…

2009

The synthesis, crystal structure, and physical characterization of two new radical salts formed by the organic donors bis(ethylenedithio)tetrathiafulvalene (ET) and bis(ethylenediseleno)tetrathiafulvalene (BETS) and the Keggin polyoxometalate (POM) [SMo(12)O(40)](n-) are reported. The salts isolated are ET(8)[SMo(12)O(40)] x 10 H(2)O (1) (crystal data: (1) monoclinic, space group I2/m with a = 13.9300(10) A, b = 43.467(3) A, c = 13.9929(13) A, beta = 107.979(6) degrees, V = 8058.9(11) A(3), Z = 2) and BETS(8)[SMo(12)O(40)] x 10 H(2)O (2) (crystal data: monoclinic, space group I2/m with a = 14.0878(2) A, b = 44.1010(6) A, c = 14.0930(2) A, beta = 106.739(3) degrees, V = 8384.8 A(3), Z = 2). …

Spin Crossover Iron(II) Coordination Polymer Chains: Syntheses, Structures, and Magnetic Characterizations of [Fe(aqin) 2 (μ 2 -M(CN) 4 )] (M = Ni(II…

2014

International audience; New Fe(II) coordination polymeric neutral chains of formula [Fe(aqin)2(μ2-M(CN)4)] (M = NiII (1) and PtII (2)) (aqin = Quinolin-8-amine) have been synthesized and characterized by infrared spectroscopy, X-ray diffraction, and magnetic measurements. The crystal structure determinations of 1–2 reveal in both cases a one-dimensional structure in which the planar [M(CN)4]2– (M = NiII (1) and PtII (2)) anion acts as a μ2-bridging ligand, and the two aqin molecules as chelating coligands. Examination of the intermolecular contacts in the two compounds reveals that the main contacts are ascribed to hydrogen bonding interactions involving the amine groups of the aqin chelati…

Semiconductive and Magnetic One-Dimensional Coordination Polymers of Cu(II) with Modified Nucleobases

2013

Four new copper(II) coordination complexes, obtained by reaction of CuX2 (X = acetate or chloride) with thymine-1-acetic acid and uracil-1-propionic acid as ligands, of formulas [Cu(TAcO)2(H2O)4]·4H2O (1), [Cu(TAcO)2(H2O)2]n (2), [Cu3(TAcO)4(H2O)2(OH)2]n·4H2O (3), and [Cu3(UPrO)2Cl2(OH)2(H2O)2]n (4) (TAcOH = thymine-1-acetic acid, UPrOH = uracil-1-propionic acid) are described. While 1 is a discrete complex, 2-4 are one-dimensional coordination polymers. Complexes 2-4 present dc conductivity values between 10(-6) and 10(-9) S/cm(-1). The magnetic behavior of complex 2 is typical for almost isolated Cu(II) metal centers. Moderate-weak antiferromagnetic interactions have been found in complex…

Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand

2009

A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand. Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es

A Co-monosubstituted Keggin polyoxometalate with an antenna ligand and three cobalt(II) chains as counterion

2009

Abstract A Co-monosubstituted Keggin polyoxometalate with an antenna ligand linked to the Co(II) center with a Co(II)-containing cation has been prepared. The title compound, formulated as {Co(H 2 O) 4 (4,4′-bpy)} 2 (4,4′-Hbpy) 2 [SiW 11 Co(4,4′-bpy)O 39 ] · 5H 2 O ( 1 ) (4,4′-bpy = 4,4′-bipyridine), was synthesized and characterized by elemental analysis, IR spectra, TG analysis, X-ray single crystal structure analysis and magnetic measurements. As far as we know, the title compound represents the first Co(II) substituted Keggin polyoxometalate with an antenna ligand structurally and magnetically characterized.

First Magnetic Observation of a Spin Crossover in a Langmuir-Blodgett Film

1999

Cover Picture: Insertion of a Single-Molecule Magnet inside a Ferromagnetic Lattice Based on a 3D Bimetallic Oxalate Network: Towards Molecular Analo…

2014

A Novel Chainlike Heteropolyanion Formed by Keggin Units: Synthesis and Structure of(ET)8n[PMnW11O39]n· 2nH2O

1995

Magnetic properties of Co–Al, Ni–Al, and Mg–Al hydrotalcites and the oxides formed upon their thermal decomposition

2002

The magnetic behaviour of Co–Al, Ni–Al, and Mg–Al hydrotalcites (HTlc) with a M2+/Al3+ molar ratio of 3 and carbonates in the interlayer, as well as the mixed oxides obtained after calcination at 823 K for 5 h, has been investigated by DC and AC magnetic susceptibility measurements and isothermal magnetisation. The samples were also characterised by ICP-OES and XRD. The magnetic measurements show that Co–Al and Ni–Al HTlcs behave as ferromagnets, with ordering temperatures of approximately 6–7 K in both cases, and displaying hysteresis loops at 2 K with coercive fields of 4.2 and 5.5 mT, respectively, whereas the Mg–Al-HTlc shows the expected diamagnetic behaviour. A solid solution of cobal…

Organocyanide coordination chemistry: Syntheses, structural characterisations and magnetic properties of copper (II) complexes with a di-imine/pyridi…

2005

Abstract The reactions between the copper (II) salts [CuXL]PF6 (L: 2,6-[1-(2,6-diisopropylphenylimino)ethyl]pyridine) (X = Cl 1, X = Br 2) and LiTCNQ, in a DMF/water mixture, or Et3NH(TCNQ)2, in acetone, produced the new complexes [CuXL(TCNQ)] (X = Cl 3, X = Br 4). For both compounds, crystallographic studies have clearly evidenced the existence of dimeric complexes [{CuClL}(TCNQ)]2 owing to π–π overlap between two adjacent TCNQ − radical anions. Compound 1 reacted with Et4N(C10N7) to afford the mononuclear derivative [CuClL(C10N7)] (5), while its reaction with K2C10N6 produced the dinuclear complex [(CuClL)2(C10N6)] (6). The crystal structures of complexes 5 and 6 have been determined by X…

Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer

2015

We present a structurally flexible copper–iodide–pyridine-based coordination polymer showing drastic variations in its electrical conductivity driven by temperature and sorption of acetic acid molecules. The dramatic effect on the electrical conductivity enables the fabrication of a simple and robust device for gas detection. X-ray diffraction studies and DFT calculations allow the rationalisation of these observations.

Double azido/cyanato bridged copper(II) dimers incorporating tridentate nitrogen donors Schiff base: Structure, EPR and magnetic studies

2015

Abstract A neutral tridentate nitrogen donor Schiff base ligand L (L = (E)-N-(phenyl(pyridin-2-yl)methylene)-2-(pyridin-2-yl)ethanamine) has been synthesized and characterized by spectroscopic techniques, and employed to synthesize two new μ1,1-azido/cyanato bridged dinuclear copper(II) complexes, [Cu(L)(μ1,1-N3)(ClO4)]2 (1) and [Cu(L)(μ1,1-NCO)(ClO4)]2 (2). Both compounds have been spectroscopically and structurally characterized. Structural investigation reveals centro-symmetric nature of the complexes in which the center of inversion lies at the midpoint of the two copper(II) ions. The metal ions display distorted octahedral geometry. The tridentate neutral ligand L coordinates the metal…

A Novel Polyoxotungstate Containing atriangulo Ni3II Cluster with Ferromagnetic Exchange Interactions and anS= 3 Ground State

1992

Aza and cyanobridged tripodal dinuclear copper(II) complexes: Electrochemical studies and structural evidence for an original azacyanocarbanion

2014

International audience; The reactivity of the mononuclear [Cu(TMPA)(L)] n+ complex (TMPA: tris(2-methylpyridine) amine, L: CH3CN, H2O) towards two different bridging species (tetracyanoethylene, 4,40-bipyridine) was investigated. The dinuclear complex [(mu-4,40-bipy)Cu-II(TMPA)(2)](CF3SO3)(4) (1) was synthesised and analysed by Xray diffraction (XRD). Magnetic studies revealed that this derivative displays very weak antiferromagnetic interactions between the two metal centres (2J = -0.69 cm(-1)). Solution studies (EPR spectroscopy and voltammetry) evidenced the lability of the bridged neutral bipyridine ligand in acetonitrile. The reaction of TCNE (TCNE: tetracyanoethylene) with the copper(…

Synthesis, crystal structures and magnetic properties of mononuclear tris(croconate)ferrate(III) complexes

2006

Abstract A straightforward synthetic method to prepare mononuclear croconato-containing iron (III) complexes, (A)3[Fe(C5O5)3] [A = tetrabutylammonium = n-Bu4N+ (1) and tetraphenylphosphonium = PPh 4 + ( 2 ) ; C 5 O 5 2 - = croconate = dianion of 4 , 5 - dihydroxycyclopent - 4 - ene - 1 , 2 , 3 - trione ] along with their crystal structures and magnetic properties, are reported. The Fe(III) atom adopts a pseudo-octahedral geometry while magnetic susceptibility measurements, in the 2–300 K temperature range, show the occurrence of a high spin state (S = 5/2) in both complexes.

Magneto-structural and theoretical study of the weak interactions in a Mn(II) complex with a very unusual N,O-chelating coordination mode of 2-aminot…

2017

International audience; The Mn(II) complex {[Mn(atpa)(H2O)2]·H2O}n (1),with the dicarboxylate ligand 2-aminoterephthalic acid (H2atpa), has been synthesized and crystallographically, spectroscopically and magnetically characterized. Complex 1 shows a very unusual 1κ2N,O coordination mode of the aminoterephthalate dianion with the Mn(II) ion. One of the carboxylate groups shows a syn-anti-μ2-η1:η1 binding mode to form a 2D square grid. The magnetic properties of this compound can be very well reproduced with a regular S = 5/2 chain model with a very weak antiferromagnetic coupling constant of J = −0.2 cm−1 through the single syn-anti carboxylate bridges. EPR measurement also supports the exp…

Magnetic LB films based upon polyoxometalate clusters and single molecule nanomagnets

1999

Abstract By using the adsorption properties of polyoxometalates such as the ferromagnetic cluster [Co 4 (H 2 O) 2 (PW 9 O 34 ] 10− ) along a positively charged monolayer, we have prepared well organized monolayers of the magnetic polyanions. A similar procedure allowed us to obtain Langmuir-Blodgett films (LB films) based on Mn 12 clusters which show a marked hysteresis

Preferential azido bridging regulating the structural aspects in cobalt(III) and copper(II)–Schiff base complexes: Syntheses, magnetostructural corre…

2011

International audience; A tridentate NNO donor Schiff base ligand [(1Z,3E)-3-((pyridin-2-yl)methylimino)-1-phenylbut-1-en-1-ol = LH] in presence of azide ions coordinates with cobalt(II) and copper(II) ions giving rise to three new coordination complexes [Co2(L)2(μ1,1-N3)2(N3)2] (1), [Cu2(L)2(μ1,3-N3)]·ClO4 (2) and [(μ1,1-N3)2Cu5(μ-OL)2(μ1,1-N3)4(μ1,1,1-N3)2]n (3). The complexes have been characterized by elemental analysis, FT-IR, UV–Vis spectral studies, and single crystal X-ray diffraction studies. These complexes demonstrate that under different synthetic conditions the azide ions and the Schiff base ligand (LH) show different coordination modes with cobalt(II) and copper(II) ions, givi…

New BEDT-TTF/[Fe(C5O5)3]3- Hybrid System:  Synthesis, Crystal Structure, and Physical Properties of a Chirality-Induced α Phase and a Novel Magnetic …

2007

The paramagnetic and chiral anion [Fe(C5O5)3]3- (C5O52-=croconate) has been combined with the organic donor BEDT-TTF (=ET=bis(ethylenedithio)tetrathiafulvalene) to synthesize a novel paramagnetic semiconductor with the first chirality-induced alpha phase, alpha-(BEDT-TTF)5[Fe(C5O5)3].5H2O (1), and one of the few known paramagnetic molecular metals, beta-(BEDT-TTF)5[Fe(C5O5)3].C6H5CN (2). Both compounds present layers of BEDT-TTF molecules, with the alpha or beta packing modes, alternating with layers containing the high-spin S=5/2 Fe(III) anions and solvent molecules. In the alpha phase, the alternation of the chiral [Fe(C5O5)3]3- anions along the direction perpendicular to the BEDT-TTF cha…

Multifunctionality in hybrid molecular materials: design of ferromagnetic molecular metals and hybrid magnets

2003

We report on the synthesis and physical properties of novel hybrid organic–inorganic molecular materials combining ferromagnetic bimetallic oxalato-based networks and functional organic molecules as the donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) or cationic nitroxide free radicals. # 2002 Elsevier Science B.V. All rights reserved.

Polyoxometalate Metal–Organic Frameworks: Keggin Clusters Encapsulated into Silver-Triazole Nanocages and Open Frameworks with Supercapacitor Perform…

2019

To investigate the relationship between the structures of polyoxometalate host–guest materials and their energy-storage performance, three novel polyoxometalate-based metal–organic compounds, [Ag10...

Electrical conductive coordination polymers

2011

Coordination polymers are currently one of the hottest topics in Inorganic and Supramolecular Chemistry. This critical review summarizes the current state-of-the-art on electrical conductive coordination polymers (CPs), also named metal-organic frameworks (MOFs). The data were collected following two sort criteria of the CPs structure: dimensionality and bridging ligands (151 references).

Crystal structure and magnetic properties of Cu(TIM)CuBr4: An alternating site-alternating exchange chain system

2007

Abstract The title compound, Cu(TIM)CuBr4 (where TIM is a macrocycle ligand) is a member of the Cu(TIM)MX4 family, which contains linear chain structures with ⋯ Cu ⋯ X – M – X ⋯ Cu ⋯ X – M - ⋯ linkages. This chain structure defines an alternating exchange/alternating site 1d system. For M=Cu, alternating FM/AFM chains are formed with JFM>| JAFM|. Structural and magnetic data are presented, along with an analysis of the exchange pathways.

Synthesis and structure of a paramagnetic Mo3S4 incomplete cuboidal cluster with seven cluster skeletal electrons

2012

The electron precise incomplete cuboidal complex [Mo(3)S(4)(dppe)(3)Br(3)]Br (1a) with 6 cluster skeletal electrons (CSE) and its halogen-mixed analogue [Mo(3)S(4)(dppe)(3)(Br,Cl)(3)](Br,Cl) (1b) can be smoothly reduced to the paramagnetic [Mo(3)S(4)(dppe)(3)X(3)] clusters (2a, X = Br; 2b, X = Cl/Br) with 7 CSE by treatment with liquid Ga.

A molecular chemical approach to the magnetic multilayers

1999

Abstract Using the bi-dimensional bimetallic networks based upon oxalate complexes, it is possible to prepare new multilayered materials by insertion of ‘electroactive’ molecules in between these layers. According to this approach a new family of compounds presenting alternating ferromagnetic—paramagnetic layers have been successfully prepared. Here we present the magnetic and specific heat characterization.

Molecular materials with conducting and magnetic properties based on ET and [ M(tdas)2]x-dithiolenes

2004

Two hybrid molecular materials showing a combination of magnetic and conducting properties, the charge-transfer (ET) 2 [Fe(tdas) 2 ] (1) and (ET)Ni(tdas) 2 (2), (ET=bis(ethylenedithio) tetrathiafulvalene; M=Fe, Ni; tdas=l,2,5-thiadiazole-3,4-dithiolate) salts, are characterized by vibrational (IR and Raman) and UV-VIS-NIR spectroscopies. These studies have proved to be effective and diagnostic tools in identifying the oxidation state (partial or integer) and the packing pattern (dimers or segregated stacks) of the ET donor only, since no v(C=C) group vibration sensitive to the charge of M(tdas) 2 complexes has been observed. This is ascribed to the extensive electron-delocalization inside t…

A chirality-induced alpha phase and a novel molecular magnetic metal in the BEDT-TTF/tris(croconate)ferrate(iii) hybrid molecular system

2006

The novel paramagnetic and chiral anion [Fe(C5O5)3]32 has been combined with the organic donor BEDT-TTF (= ET = bis(ethylenedithio)tetrathiafulvalene) to yield the first chirality- induced α phase and a paramagnetic metal. Gomez Garcia, Carlos, Carlos.Gomez@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es ; Gimenez Saiz, Carlos, Carlos.Gimenez@uv.es

Ein aus Keggin-Einheiten aufgebautes, kettenartiges Heteropolyanion: Synthese und Struktur von (ET)8n[PMnW11O39]n · 2nH2O

1995

Hybrid Molecular Materials Based upon Magnetic Polyoxometalates and Organic π-Electron Donors:  Syntheses, Structures, and Properties of Bis(ethylene…

1998

International audience; The syntheses, crystal structures, and physical properties of the series of radical salts made with bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) and monosubstituted α-Keggin polyoxoanions of formula [XZ(H2O)M11O39]5- (XZM11 = Si(IV)Fe(III)Mo11, Si(IV)Cr(III)W11, P(V)Con(II)W11, P(V)Ni(II)W11, P(V)Cu(II)W11 P(V)Zn(II)W11, P(V)Mn(II)W11, and P(V)Mn(II)Mo11) containing a magnetic metal ion Z on a peripheral octahedral site of the Keggin union are reported. They all crystallize in two related series called α2 and α3. The general structure consists of alternating layers of the organic donor and the Keggin polyoxometalates. While the stoichiometry and α-packing a…

Toward new organic/inorganic superlattices: Keggin polyoxometalates in Langmuir and Langmuir-Blodgett films

1997

The effect of Keggin heteropolyoxotungstates (XW12O40n- with X = H2, P, Si, B or Co) on Langmuir films has been studied for monolayers of DODA (dimethyldioctadecylammonium) and DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine). Marked modifications of the compression isotherms have been observed when the Keggin anions were dissolved in the subphase:  this demonstrates that the polyanions interact with the monolayer. Langmuir−Blodgett (LB) films have been readily obtained from these systems (even with DPPC) for a particular range in polyanion concentration. X-ray diffraction and infrared dichroism experiments have shown a well-defined lamellar structure for these built-up films as well a…

Monoradicals and Diradicals of Dibenzofluoreno[3,2-b]fluorene Isomers: Mechanisms of Electronic Delocalization

2020

The preparation of a series of dibenzo- and tetrabenzo-fused fluoreno[3,2-b]fluorenes is disclosed, and the diradicaloid properties of these molecules are compared with those of a similar, previously reported series of anthracene-based diradicaloids. Insights on the diradical mode of delocalization tuning by constitutional isomerism of the external naphthalenes has been explored by means of the physical approach (dissection of the electronic properties in terms of electronic repulsion and transfer integral) of diradicals. This study has also been extended to the redox species of the two series of compounds and found that the radical cations have the same stabilization mode by delocalization…

Spin crossover (SCO) iron(II) coordination polymer chain: Synthesis, structural and magnetic characterizations of [Fe(abpt)2(μ-M(CN)4)] (M=PtII and N…

2013

Abstract New iron(II) coordination polymeric neutral chain of formula [Fe(abpt) 2 (μ-M(CN) 4 )], with M = Pt II ( 1 ), Ni II ( 2 ) and abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole, have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. The two compounds are isostructural as deduced from a Rietveld analysis of X-ray powder diffraction data of 2 simulated from the single crystal structure of 1 . The crystal packing of 1 is formed by regular chains running along the crystallographic [−1 0 1] direction where the planar [Pt(CN) 4 ] 2− anion acts as a μ 2 -bridging ligand via two nitrogen atoms of two different trans cyano groups, whi…

Magnetic properties of MoS 2 nanotubes doped with lithium

2003

DC magnetization measurements of lithium-doped molybdenum sulfide nanotubes (LixMoS2, 2.2 10 kOe, the nonlinear part in H<5 kOe with saturation at approximately 10 kOe can be observed. This suggests a formation of ferromagnetic clusters even at room temperature. No magnetic phase transition between 2 and 300 K has been detected.

Metallic Charge‐Transfer Salts of Bis(ethylenedithio)tetrathiafulvalene with Paramagnetic Tetrachloro(oxalato)rhenate(IV) and Tris(chloranilato)ferra…

2014

The synthesis, crystal structure and physical characterization of three radical salts of the donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) and tetrachloro(oxalato)rhenate(IV) {[ReCl4(C2O4)]2–} or tris(chloranilato)ferrate(III) {[Fe(C6O4Cl2)3]3–} anions are reported. The isolated salts with ReIV are (ET)[ReCl4(C2O4)] [1, monoclinic, space group C2/c with a = 18.3409(3) A, b = 10.8414(2) A, c = 11.1285(3) A, β = 99.9714(7)°, V = 2179.38(8) A3, Z = 4] and (ET)4[ReCl4(C2O4)]·C6H5CN [2, monoclinic, space group P21/c with a = 11.8549(2) A, b = 32.9079(5) A, c = 36.4154(5) A, β = 96.742(2)°, V = 14108.1(4) A3, Z = 8]. The salt with FeIII is (ET)6[Fe(C6O4Cl2)3]·(H2O)1.5·(CH2Cl2)0.5 […

Molecular Materials from Polyoxometalates

2006

The present article highlights recent results and provide a perspective of the interest of polyoxometalates as inorganic component of molecular materials with active physical properties. Three different aspects will be presented: i) The interest of the magnetic and mixed valence clusters provided by polyoxometalate chemistry in molecular magnetism; ii) The use of these inorganic anions as magnetic component of crystalline conducting materials based on organic donor molecules; iii) The construction of well-organized films of polyoxometalate monolayers by using the Langmuir-Blodgett technique.

Unusual Magnetic State in Lithium-DopedMoS2Nanotubes

2003

We report on the very peculiar magnetic properties of an ensemble of very weakly coupled lithium-doped MoS2 nanotubes. The magnetic susceptibility chi of the system is nearly 3 orders of magnitude greater than in typical Pauli metals, yet there is no evidence for any instability which would alleviate this highly frustrated state. Instead, the material exhibits peculiar paramagnetic stability down to very low temperatures, with no evidence of a quantum critical point as T-->0 in spite of clear evidence for strongly correlated electron behavior. The exceptionally weak intertube interactions appear to lead to a realization of a near-ideal one-dimensional state in which fluctuations prevent the…

Hybrid Magnetic Materials Based on Nitroxide Free Radicals and Extended Oxalato‐Bridged Bimetallic Networks

2005

A series of hybrid organic-inorganic magnets of formula p-rad[MIICr(ox)3] [M = Mn (1), Co (2), Ni (3), Zn (4)] and m-rad[MIICr(ox)3] [M = Mn (5), Co (6)], in which N-methylpyridinium cations bearing a nitronyl nitroxide moiety in positions 3 (m-rad) or 4 (p-rad) of the pyridine ring coexist with the 2D honeycomb-like oxalato-bridged bimetallic lattice, has been prepared and studied by AC and DC magnetic susceptibility measurements and EPR spectroscopy. In general, the physical properties of these magnets are not altered significantly by the insertion of the nitronyl nitroxide radicals although these paramagnetic molecules seem to interact weakly with the inorganic network as demonstrated by…

Effects of water removal on the structure and spin-crossover in an anilato-based compound

2021

The crucial role played by a crystallization water molecule in the spin crossover (SCO) temperature and its hysteresis is described and discussed in compound [NBu4][Fe(bpp)2][Cr(C6O4Br2)3]⋅2.5H2O (1), where bpp = 2,6-bis(pyrazol-3-yl)pyridine and (C6O4Br2)2− = dianion of the 3,6-dibromo-2,5-dihydroxy-1,4-benzoquinone. The compound has isolated [Fe(bpp)2]2+ cations surrounded by chiral [Cr(C6O4Br2)3]3− anions, NBu4+ cations, and a water molecule H-bonded to one of the non-coordinated N–H groups of one bpp ligand. This complex shows a gradual almost complete two-step spin transition centered at ca. 180 and 100 K with no hysteresis. The loss of the water molecules results in a phase transition…

Electrical Behaviour of Heterobimetallic [MM′(EtCS2)4] (MM′=NiPd, NiPt, PdPt) and MM′X-Chain Polymers [PtM(EtCS2)4I] (M=Ni, Pd)

2012

Herein, we report the isolation of new heterobimetallic complexes [Ni0.6Pd1.4ACHTUNGTRENUNG(EtCS2)4] (1), [NiPtACHTUNGTRENUNG(EtCS2)4] (2) and [Pd0.4Pt1.6ACHTUNGTRENUNG(EtCS2)4] (3), which were constructed by using transmetallation procedures. Subsequent oxidation with iodine furnished the MM'X monodimensional chains [Ni0.6Pt1.4ACHTUNGTRENUNG(EtCS2)4I] (4) and [Ni0.1Pd0.3Pt1.6ACHTUNGTRENUNG(EtCS2)4I] (5). The physical properties of these systems were investigated and the chain structures 4 and 5 were found to be reminiscent of the parent [Pt2ACHTUNGTRENUNG(EtCS2)4I] species. However, they were more sensitively dependent on the localised nature of the charge on the Ni ion, which caused spont…

Linkage isomerism in coordination polymers.

2012

The use of the recently prepared polynitrile ligand tcnopr3OH(-) ([(NC)(2)CC(OCH(2)CH(2)CH(2)OH)C(CN)(2)](-)) with different salts of Fe(II), Co(II), and Ni(II) has led to a very rare example of linkage isomerism in a coordination chain. These pairs of linkage isomers can be formulated as [M(tcnopr3OH-κN,κO)(2)(H(2)O)(2)]; M = Fe (1), Co (3), and Ni(5) and [M(tcnopr3OH-κN,κN')(2)(H(2)O)(2)]; M = Fe (2), Co (4), and Ni (6). Compounds 1-2, 3-4, and 5-6 are three pairs of linkage isomers since they present the same formula and chain structure and they only differ in the connectivity of the polynitrile ligand bridging the metal ions in the chain: through a N and an O atom (1κN:2κO-isomer) or th…

Intrinsic electrical conductivity of nanostructured metal-organic polymer chains

2012

One-dimensional conductive polymers are attractive materials because of their potential in flexible and transparent electronics. Despite years of research, on the macro- and nano-scale, structural disorder represents the major hurdle in achieving high conductivities. Here we report measurements of highly ordered metal-organic nanoribbons, whose intrinsic (defect-free) conductivity is found to be 104 S m−1, three orders of magnitude higher than that of our macroscopic crystals. This magnitude is preserved for distances as large as 300 nm. Above this length, the presence of structural defects (~ 0.5%) gives rise to an inter-fibre-mediated charge transport similar to that of macroscopic crysta…

Diindenoanthracene Diradicaloids Enable Rational, Incremental Tuning of Their Singlet-Triplet Energy Gaps

2020

Summary A fundamental understanding of the inherent electronic and magnetic properties of open-shell diradicaloids is essential so that these properties can be modified to create molecules that meet the potential needs of industry. However, there have been very few attempts to date to systematically accomplish this in diradicaloid compounds. Here, we present the synthetic, spectroscopic, and computational investigation of a series of molecules based on the diindeno[1,2-b:1′,2′-g]anthracene framework. Calculations suggest that by altering the transfer integral term, tab, we are able to manipulate the diradical character and, thus, ΔEST within this series of molecules. Experimentally determin…

Langmuir-Blodgett Films of Magnetic Clusters

1999

Abstract The mixed-valence manganese clusters [Mn12O12(carboxylato)16] have been organized in a multilayer architecture. Indeed, well-defined Langmuir-Blodgett (LB) films of the acetate and the benzoate Mn12 clusters can be obtained using behenic acid as organic matrix. Here, we report the magnetic properties of these multilayers, which present a marked hysteresis at 2 K.

Hybrid Molecular Materials Based upon the Photochromic Nitroprusside Complex, [Fe(CN)5NO]2-, and Organic π-Electron Donors. Synthesis, Structure, and…

2000

An organic/inorganic hybrid salt is obtained by combination of the photochromic nitroprusside complex with the organic donor TTF. The organic part shows an unprecedented 2D organization formed by an orthogonal arrangement of TTF hexamers and monomers. However, the donor layers are formed by pairs of moderately interacting dimeric (TTF)22+ units surrounded by neutral TTF molecules in such a way that the charge is localized and the compound is a semiconductor. Short contacts between the organic layers and the nitroprusside anions are present that may affect the photophysical properties of the nitroprusside.

A bioinspired metal–organic approach to cross-linked functional 3D nanofibrous hydro- and aero-gels with effective mixture separation of nucleobases …

2020

The direct reaction between Cu(CH3COO)2 and uracil-1-acetic acid in water gives rise to the formation of a hydrogel consisting of entangled nanometric ribbons of a crystalline antiferromagnetic 1D Cu(ii) coordination polymer (CP) decorated with biocompatible uracil nucleobases. This hydrogel is the precursor for the preparation of a meso/macroporous ultralight aerogel that shows a remarkable Young's modulus. As a proof-of-concept of the molecular recognition capability of the terminal uracil moieties anchored at Cu(ii) CP chains, this material has been tested as the selective stationary phase for the separation of nucleobase derivatives in HPLC columns.

Cyanocarbanion-based spin-crossover materials: photocrystallographic and photomagnetic studies of a new iron(II) neutral chain

2010

International audience; A new iron(II) chain of formula [Fe(abpt)(2)(tcpd)] [1; (tcpd)(2-) = [C(10)N(6)](2-) = (C[C(CN)(2)](3))(2-) = 2-dicyanomethylene-1,1,3,3-tetracyanopropanediide anion, abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole] has been synthesized and characterized by IR spectroscopy, detailed variable-temperature single-crystal X-ray diffraction, magnetic and photomagnetic measurements. The crystal structure determination of 1 reveals a one-dimensional structural architecture in which the (tcpd)(2-) cyanocarbanion acts as a μ(2)-bridging ligand and the two abpt molecules act as chelating ligands. Detailed X-ray diffraction studies as a function of the temperature (293-10 K…

Oxalate‐Based 3D Chiral Magnets: The Series [Z II (bpy) 3 ][ClO 4 ][M II Fe III (ox) 3 ] (Z II = Fe, Ru; M II = Mn, Fe; bpy = 2,2'‐Bipyridine; ox = O…

2005

The synthesis, structure, and physical properties of the oxalate-based molecular magnets with the formula [ZII(bpy)3][ClO4][MIIFeIII(ox)3] (ZII = Fe, Ru; MII = Mn, Fe; bpy = 2,2'-bipyridine; ox = oxalate dianion) are presented here. All compounds are isostructural and crystallize in the chiral cubic space group P4132, and contain three-dimensional dimetallic networks formed by alternating MII and MIII ions that are connected by oxalate anions. These compounds exhibit strong antiferromagnetic interactions that give rise to magnetic ordering as ferrimagnets or weak ferromagnets, with critical temperatures of up to 20 K, which is twice as high as those found for the isostructural magnets based…

Multifunctional molecular materials

2003

A Tale of Two Isomers: Enhanced Antiaromaticity/Diradical Character versus Deleterious Ring‐Opening of Benzofuran‐fused s ‐Indacenes and Dicyclopenta…

2021

We examine the effects of fusing two benzofurans to s-indacene (indacenodibenzofurans, IDBFs) and dicyclopenta[b,g]naphthalene (indenoindenodibenzofurans, IIDBFs) to control the strong antiaromaticity and diradical character of these core units. Synthesis via 3-functionalized benzofuran yields syn-IDBF and syn-IIDBF. syn-IDBF possesses a high degree of paratropicity, exceeding that of the parent hydrocarbon, which in turn results in strong diradical character for syn-IIDBF. In the case of the anti-isomers, synthesized via 2-substituted benzofurans, these effects are decreased; however, both derivatives undergo an unexpected ring-opening reaction during the final dearomatization step. All th…

Charge transfer salts of tetrathiafulvalene derivatives with magnetic iron(III) oxalate complexes: [TTF]7[Fe(ox)3]2·4H2O, [TTF]5[Fe2(ox)5]·2PhMe·2H2O…

2000

Three novel TTF (tetrathiafulvalene) and TMTTF (tetramethyltetrathiafulvalene) radical salts of monomeric and dimeric iron(III) oxalate magnetic complexes, [TTF]7[Fe(ox)3]2·4H2O 1, [TTF]5[Fe2(ox)5]·2PhMe·2H2O 2 and [TMTTF]4[Fe2(ox)5]·PhCN·4H2O 3, have been synthesized, and their structures and physical properties investigated. The structures for these semiconducting salts feature monodimensional stackings of the radical cations interleaved by the complexes [Fe(ox)3]3− and [Fe2(ox)5]4−, and solvent molecules. For the novel dinuclear complex [Fe2(ox)5]4− antiferromagnetic exchange between the two iron atoms through the oxalate bridge was found.

Magneto-structural correlations and DFT calculations in two rare tetranuclear copper(II)-clusters with doubly phenoxo and end-on azido bridges: Synth…

2010

International audience; By slightly changing the synthetic conditions, we have prepared two closely related linear tetranuclear CuII complexes with the symmetrical ONNO donor tetradentate Schiff-base ligand [H2L = (OH)C6H4(CH3)Cdouble bond; length as m-dashN(CH2)3Ndouble bond; length as m-dashC(CH3)C6H4(OH)] and with azide ions. These two distinctly coloured crystalline products were characterized by elemental analysis, IR and UV–Vis spectroscopy, CV, EPR spectra and variable temperature magnetic measurements. Single crystal X-ray diffraction studies of the green [Cu4(μ-L)2(μ1,1-N3)2(N3)2] (1) and the red [Cu4(μ-L)2(μ1,1-N3)2(N3)2(H2O)2] (2) crystals show that the coordination environment o…

A New Heptanuclear Cobalt(II) Cluster Encapsulated in a Novel Heteropolyoxometalate Topology:  Synthesis, Structure, and Magnetic Properties of [Co7(…

2004

The synthesis and the structural and magnetic characterization of a novel heptanuclear cobalt cluster encapsulated in a heteropolyoxotungstate is reported. This complex shows how it is possible to control the nuclearity of the Co clusters formed in a tungstate solution by slightly changing the synthetic conditions, and the relevance of pH in this regard. This heptanuclear complex [Co7(H2O)2(OH)2P2W25O94]16- (Co7) crystallizes in the triclinic space group P1 (a = 12.3403(6) A, b = 22.5966(11) A, c = 23.2645(12) A, α = 68.7830(11)°, β = 83.7981(12)°, γ = 78.5423(13)°, V = 5922.4(5) A3, Z = 2) and is formed by six CoO6 octahedra from two Co3 trimers sustained by Keggin trivacant fragments held…

Trinuclear Mo3S7 clusters coordinated to dithiolate or diselenolate ligands and their use in the preparation of magnetic single component molecular c…

2008

A general route for the preparation of a series of dianionic Mo3S7 cluster complexes bearing dithiolate or diselenolate ligands, namely, [Mo3S7L3](2-) (where L = tfd (bis(trifluoromethyl)-1,2-dithiolate) (4(2-)), bdt (1,2-benzenedithiolate) (5(2-)), dmid (1,3-dithia-2-one-4,5-dithiolate) (6(2-)), and dsit (1,3-dithia-2-thione-4,5-diselenolate) (7(2-))) is reported by direct reaction of [Mo3S7Br6](2-) and (n-Bu)2Sn(dithiolate). The redox properties, molecular structure, and electronic structure (BP86/VTZP) of the 4(2-) to 7(2-) clusters have also been investigated. The HOMO orbital in all complexes is delocalized over the ligand and the Mo3S7 cluster core. Ligand contributions to the HOMO ra…

Syntheses, structures and physical characterization of two new three-dimensional mixed-valence hexadecavanadate derivatives

2007

Abstract Two new hexadecavanadate derivatives, (bpy)[Zn(4,4′-bpy)2]2[H4ClV16O38]·6H2O 1 and (bpy)[Co(4,4′-bpy)2]2[H4ClV16O38]·6H2O 2 (bpy = 4,4′-bipyridine), were synthesized under the hydrothermal conditions and structurally characterized by IR, XPS and EPR spectroscopy, redox titration and single-crystal X-ray diffraction. The two compounds are isostructural and crystallize in the tetragonal non-centrosymmetric space group P-4n2 (No. 118) with a = 17.124(2), b = 17.124(2), c = 14.724(3) A, V = 4317.5(12) A3 and Z = 1 for the compound 1, and a = 17.038(2), b = 17.038(2), c = 14.754(3) A, V = 4282.9(12) A3 and Z = 1 for the compound 2. Compounds 1 and 2 were constructed from 4-connected {H4…

Synthesis, crystal structure and magnetic properties of [Cr2Cu2(bpy)4(ox)5]·2H2O. An oxalato-bridged heterometallic tetramer

2003

A new heterometallic tetramer of formula [Cr2Cu 2(bpy)4(ox)5]·2H2O (1) (bpy=2,2′-bipyridine; ox=oxalate dianion) has been prepared and characterised by single-crystal X-ray diffraction, magnetic susceptibility measurements and ESR spectroscopy. The tetranuclear unit in 1 can be viewed as the combination of two terminal [Cr(bpy)2(ox)]- units with a central oxalato-bridged copper(II) dimer. The chromium ions are in a distorted octahedral environment with metal-ligand distances ranging from 1.944(4) to 2.064(5) A. The copper(II) centres lie in an axially distorted octahedron. The axial positions are occupied by one oxygen atom belonging to the central bridging oxalate anion [O(9)-Cu(1): 2.245(…

Increasing the Coercivity in Layered Molecular-based Magnets A[MIIMIII(ox)3] (MII = Mn, Fe, Co, Ni, Cu; MIII = Cr, Fe; ox = oxalate; A = organic or o…

1999

Magnetic transition metal complexes of tetrathiafulvalene (TTF) derivatives

1997

We have prepared and characterized the transition metal complexes of two different TTF derivatives. We have oxidized the different complexes with electrooxidation and chemical oxidation techniques and the results are discussed. The magnetic properties of the complexes have been studied. TTF-carboxylate chelates are not stable enough, but thioether-TTF shows promising charge transfer salts.

Radical salts of TTF derivatives with the metal-metal bonded [Re2Cl8]2- anion

2008

Abstract Four new salts of the radical cations of TMTSF (tetramethyltetraselenafulvalene), TMTTF (tetramethyltetrathiafulvalene), BEDT-TTF (bisethylenedithiotetrathia-fulvalene) (ET) and o-Me2TTF (o-4,4′-dimethyltetrathiafulvalene) with the metal–metal bonded dianion [Re2Cl8]2− were synthesized, and their structures and physical properties investigated. The structures of these semiconducting salts feature one-dimensional stacking of the donor molecules interleaved with [Re2Cl8]2− anions and interstitial solvent molecules.

Polyoxometalate Monolayers in Langmuir-Blodgett Films

2005

Langmuir and Langmuir-Blodgett (LB) films of a variety of polyoxometalates of different shapes, sizes, and charges were prepared by taking advantage of the adsorption properties of these polyanions on a positively charged monolayer of an organic surfactant spread on water. Three different aspects were investigated. 1) The electrochemical and electrochromic properties of LB films containing the easily reducible polyoxoanion [P2Mo18O62]6-. Absorbance changes of these LB films deposited onto an ITO substrate have been induced by repeated switching of the applied potential. These changes are due to the formation of the colored reduced forms of the polyanion. Coloration and bleaching of the LB f…

MMX Chains and Molecular Species Containing Rh 2 n+ ( n = 4, 5, and 6) Units: Electrical Conductivity in Crystal Phase of MMX Polymers

2010

The control of the experimental conditions in the reaction of Rh 2 (O 2 CCH 3 ) 4 with halides allows the isolation of the novel dirhodium complexes K x [Rh 2 X(O 2 CCH 3 ) 4 ] x ·4xH 2 O (X = Br, 1·4H 2 O and I, 2·4H 2 O) [Rh 2 (O 2 CCH 3 ) 4 Cl] x H 2 O (3·H 2 O), [Rh 2 (O 2 CCH 3 )Cl] x ·4xH 2 O (3·4H 2 O), and {Rh 2 (O 2 CCH 3 ) 4 I 2 ]· 4H 2 0 (4·4H 2 O) containing Rh 2 n+ (n = 4, 5 and 6) units. The X-ray structure determination of compounds 1-4 reveals the presence of dirhodium units in different oxidation states. The polyanionic complexes 1·4H 2 O and 2·4H 2 O containing Rh 2 4+ units give zig-zag chains. In contrast, the partially oxidized complexes 3·H 2 O and 3·4H 2 O containing …

Encapsulation of single-molecule magnets in carbon nanotubes

2011

Next-generation electronic, photonic or spintronic devices will be based on nanoscale functional units, such as quantum dots, isolated spin centres or single-molecule magnets. The key challenge is the coupling of the nanoscale units to the macroscopic world, which is essential for read and write purposes. Carbon nanotubes with one macroscopic and two nanoscopic dimensions provide an excellent means to achieve this coupling. Although the dimensions of nanotube internal cavities are suitable for hosting a wide range of different molecules, to our knowledge, no examples of molecular magnets inserted in nanotubes have been reported to date. Here we report the successful encapsulation of single-…

Supramolecular 2D/3D isomerism in a compound containing heterometallic Cu(II)2Co(II) nodes and dicyanamide bridges.

2014

Three new heterometallic copper(II)-cobalt(II) complexes [(CuL(2))2Co{dca}2]·H2O(1), [(CuL(1))2Co{dca}2]n (2a), and [(CuL(1))2Co{dca}2]n (2b) [dca(-) = dicyanamide = N(CN)2(-)] have been synthesized by reacting the "metallo-ligand" [CuL(1)] or [CuL(2)] with cobalt(II) perchlorate and sodium dicyanamide in methanol-water medium (where H2L(1) = N,N'-bis(salicylidene)-1,3-propanediamine and H2L(2) = N,N'-bis(α-methylsalicylidene)-1,3-propanediamine). The three complexes have been structurally and magnetically characterized. Complex 1 is a discrete trinuclear species in which two metallo-ligands coordinate to a cobalt(II) ion through the phenoxido oxygen atoms along with two terminally coordina…

A convenient approach to amphiphilic hyperbranched polymers with thioether shell for the preparation and stabilization of coinage metal (Cu, Ag, Au) …

2014

Halogen bonding interactions with the [Mo3S7Cl6]2-cluster anion in the mixed valence salt [EDT-TTFI2]4[Mo3S7Cl6]oCH3CN

2008

Electrocrystallization of iodinated TTF molecules in presence of trinuclear [Mo3S7Cl6]2- cluster anions provides the first example of radical salts with halogen bonding interactions at the organic/inorganic interface

Synthesis, molecular and electronic structures of a paramagnetic trimetallic cluster containing an unusual Mo3(μ3-Se)2(μ-Se)3 core

2014

Abstract The electron precise [Mo3(μ3-Se)(μ-Se)3(dppe)3Br3]+ incomplete cuboidal complex, with six cluster skeletal electrons (CSE), was converted into the paramagnetic bicapped [Mo3(μ3-Se)2(μ-Se)3(dppe)3]+ cluster (1+), with an unusual seven metal electron population, by treatment with elemental Ga. The cluster core consists of an almost equilateral Mo3 triangle (Mo–Mo distances are in the range 2.7583(7)–2.7748(7) A with an average value of 2.77(3) A), capped by two selenide ligands. The remaining selenium atoms bridge adjacent metal atoms, defining a virtually planar Mo3(μ-Se)3 unit, with the capping Se atoms positioned above and below this plane. The new complex possesses a doublet grou…

2D and 3D Anilato-Based Heterometallic M(I)M(III) Lattices: The Missing Link

2015

The similar bis-bidentate coordination mode of oxalato and anilato-based ligands is exploited here to create the first examples of 2D and 3D heterometallic lattices based on anilato ligands combining M(I) and a M(III) ions, phases already observed with oxalato but unknown with anilato-type ligands. These lattices are prepared with alkaline metal ions and magnetic chiral tris(anilato)metalate molecular building blocks: [M(III)(C6O4X2)3](3-) (M(III) = Fe and Cr; X = Cl and Br; (C6O4X2)(2-) = dianion of the 3,6-disubstituted derivatives of 2,5-dihydroxy-1,4-benzoquinone, H4C6O4). The new compounds include two very similar 2D lattices formulated as (PBu3Me)2[NaCr(C6O4Br2)3] (1) and (PPh3Et)2[KF…

New coordination polymers based on a novel polynitrile ligand: Synthesis, structure and magnetic properties of the series [M(tcnoetOH)2(4,4′-bpy)(H2O…

2008

International audience; A novel polynitrile anionic ligand, tcnoetOH−(=[(NC)2CC(OCH2CH2OH)C(CN)2]−), has been synthesized by a one-pot reaction from a cyclic acetal and malononitrile. This ligand has been successfully used to prepare, with 4,4′-bpy as co-ligand, a novel series of coordination polymers formulated as [M(tcnoetOH)2(4,4′-bpy)(H2O)2] with M(II) = Fe (1), Co (2) and Ni (3). These isostructural compounds present a linear chain structure consisting of octahedrally coordinated metal ions bridged by trans 4,4′-bpy ligands. The coordination sphere of the metal ions is completed with two terminal tcnoetOH− ligand and two water molecules. The magnetic properties indicate that the three …

Synthesis and characterisation of polymeric manganese and zinc 5-hydroxyisophthalates

2001

Abstract The crystallisation of 5-hydroxyisophthalic acid with divalent Mn or with Mn or Zn and either 2,2-bipyridine (2,2-bipy) or pyridine-2-(1H-pyrazol-3-yl) gave solids of composition [Mn(C8H4O5)(H2O)3]·2H2O (1), [Mn(C8H4O5)(2,2′-bipy)]·H2O (2), [Mn2(C8H4O5)2(C8H7N3)2]·H2O (3) and [Zn(C8H4O5)(2,2′-bipy)] (4). Each compound has 1D co-ordinative chains that are connected by hydrogen bonds. Compounds 2–4 contain M2C2O4 rings with pseudo-chair geometries. The Mn atoms in 2 are coupled antiferromagnetically.

A crystalline and free-standing silver thiocarboxylate thin-film showing high green to yellow luminescence

2016

The simple direct synthesis of Cu(ii) and Ag(i) salts and thiobenzoic acid under ambient conditions allows the preparation of two bidimensional coordination polymers [M(TB)] (TB = thiobenzoate; M = Cu (1) or Ag (2)). Their electrical and luminescent properties show that these are multifunctional materials. Interestingly 1 and 2 undergo a reversible solubilization process. This unusual feature and their simple preparation allow us to prepare a crystalline and free-standing thin-film of 2, using an interfacial procedure, which shows a remarkable thermochromic luminescence.

Effect of the lanthanoid-size on the structure of a series of lanthanoid-anilato 2-D lattices

2018

AbstractWe report the synthesis and characterization of a series of Ln-based bromoanilato 2-D lattices with dimethyl sulfoxide (DMSO): [Ln2(C6O4Br2)3(DMSO)n]·2DMSO·mH2O with n = 6 and m = 0 for Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6) and Gd (7); n = 4 and m = 2 for Ln = Tb (8), Dy (9), Ho (10), Er (11), Tm (12) and Yb (13) (C6O4Br22− = 3,6-dibromo-2,5-dihydroxy-1,4-benzoquinone = bromoanilato). The X-ray analysis shows that the largest Ln(III) ions (La-Gd, 1-7) crystallize in the monoclinic P21/n space group (phase I), whereas the smaller Ln(III) ions (Tb–Yb, 8–13) crystallize in the triclinic P-1 space group (phase II). Both phases present a (6,3)-2-D topology but show importan…

Metallic Conductivity Down to 2 K in a Polyoxometalate-Containing Radical Salt of BEDO-TTF

2004

Direct formation of Sub-Micron and Nanoparticles of a bioinspired coordination polymer based on Copper with Adenine

2017

We report on the use of different reaction conditions, e.g., temperature, time, and/or concentration of reactants, to gain control over the particle formation of a bioinspired coordination polymer based on copper(II) and adenine, allowing homogeneous particle production from microto submicro-, and up to nano-size. Additionally, studies on this reaction carried out in the presence of different surfactants gives rise to the control of the particle size due to the modulation of the electrostatic interactions. Stability of the water suspensions obtained within the time and pH has been evaluated. We have also studied that there is no significant effect of the size reduction in the magnetic prope…

Radical cation salts of BEDT-TTF, enantiopure tetramethyl-BEDT-TTF, and TTF-Oxazoline (TTF-Ox) donors with the homoleptic TRISPHAT anion

2011

International audience; The synthesis and crystal structures of five radical cation salts based on the organic donors bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF), racemic ethylenedithio-methyl-oxazoline-tetrathiafulvalene (EDT-TTF-MeOx) and the enantiopure (S,S,S,S) and (R,R,R,R) tetramethyl-bis(ethylenedithio)tetrathiafulvalene (TMBEDT-TTF) and the D3-symmetric anion tris(tetrachlorobenzenediolato)phosphate(V) (TRISPHAT) are reported. The salts are formulated as [BEDT-TTF][(rac)-TRISPHAT]·CH2Cl2 (1), [BEDT-TTF][(rac)-TRISPHAT]·2CH3CN (2), [(rac)-EDT-TTF-Ox][(rac)-TRISPHAT]·CH3CN (3), [(S,S,S,S)-TMBEDT-TTF][(rac)-TRISPHAT]·2CH3CN (4), and [(R,R,R,R)-TMBEDT-TTF][(rac)-TRISPHAT]·2CH3CN (…

Structural diversity in charge transfer salts based on Mo3S7 and Mo3S4Se3 clusters complexes and bis(ethylenedithio)tetrathiafulvalene (ET)

2007

Chemical modification of the trinuclear [Mo3(μ3-S)(μ2-S2)3Br6]2− cluster, at either the outer bromine or the disulfide ligands, allows the facile preparation of the dianions [Mo3(μ3-S)(μ2-S2)3(tdas)3]2− ([1]2−) (tdas = 1,2,5-thiadiazole-3,4-dithiol), [Mo3(μ3-S)(μ2-SSe)3Br6]2− ([2]2−) and [Mo3(μ3-S)(μ2-S2)3Cl6]2− ([3]2−). Electrocrystallization of bis(ethylenedithio)tetrathiafulvalene (ET) in the presence of these dianions affords a series of charge transfer salts, namely (ETA)(ETB)[1], (ETA)(n-Bu4N)[2], (ETA)(ETB)[3]2·CH3CN, and ((ETA)(ETB)(ETC)(ETD))2{[3]2Cl}·CH3CN, where the ET subscripts denote crystallographically independent molecules. In all cases, the various cluster–cluster, cluster…

Trinuclear Lanthanide Coordination Clusters: Single-Molecule-Magnet Behavior and Catalytic Activity in the Friedel-Crafts Alkylation Reaction.

2019

A new multidentate ligand (H3 L) was synthesized by the condensation reaction of 4-tert-butyl-2,6-diformylphenol and 2-amino-4-nitrophenol. The reaction of the ligand with hydrated lanthanide nitrate produced two isostructural trinuclear coordination clusters: [DyLn3 L3 (DMF)3 (H2 O)2 ] ⋅ 3.8DMFLn=Dy (1) and Nd (2) (DMF=N, N-dimethylformamide). Single-crystal X-ray diffraction analysis revealed that there are three lanthanide ions arranged in an almost perfect linear fashion in both complexes. Magnetic studies show single-molecule-magnet (SMM) behavior in the Dy derivative with τ0 =1.7×10-6  s and a thermal energy barrier of 7.0 cm-1 . Both complexes were used as catalysts towards the Fried…

New magnetic conductors and superconductors based on BEDT-TTF and BEDS-TTF

2005

Abstract Here we present our last results in the search for multifunctionality in conducting molecular materials obtained by combining paramagnetic molecular complexes with organic donors to produce paramagnetic molecular metals and superconductors. The structural and physical characterization of two new molecular paramagnetic superconductors ET 4 [H 3 OM(C 2 O 4 ) 3 ].PhBr (M III  = Cr and Fe) are presented (ET = BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene). These salts present a superconductor transition at T c  = 1.5 and 4.0 K, respectively and very anisotropic critical fields H c2a ≈ H c2b ≈0.5 T and H C2C ≈ 8 T for the Fe derivative. We will also present the structural and physica…

Charge Transfer Salts Based on Polyoxometalates and Seleno-Substituted Organic Donors. Synthesis, Structure, and Magnetic Properties of (BEST)3H[PMo1…

1998

Electrochemical oxidation of the tetrathiafulvalene (TTF) type organic donor bis(ethylenediseleno)tetrathiafulvalene (BEST) in the presence of the Keggin polyoxometalate [PMo12O40]3- affords the radical salt formulated as (BEST)3H[PMo12O40] (crystal data:  triclinic, space group P1 with a = 13.056(1) A, b = 13.957(1) A, c = 22.302(3) A, α = 97.019(9)°, β = 94.17(1)°, γ = 95.847(9)°, and Z = 2). This is the first salt of a selenium-containing donor with a polyoxometalate cluster. The structure of this organic/inorganic hybrid consists of layers of the organic donors that alternate with polyoxometalate layers in the c direction. The organic molecules, which are completely ionized, form two ty…

Langmuir-Blodgett films based on Prussian Blue derivatives: Towards new hybrid magnetic materials

1999

Abstract The adsorption of dissolved Prussian Blue derivatives along a positively charged monolayer leads to new Langmuir-Blodgett (LB) films presenting a ferromagnetic state at low temperature. Such organic/inorganic systems containing inorganic sheets between organic amphiphilic layers constitute a new series of magnetic lamellar materials.

Hybrid molecular magnets incorporating organic donors and other electroactive molecules

1999

Molecule-based bidimensional ferromagnets can be used as anionic hosts for electroactive molecules, with the aim of obtaining multiproperty materials exhibiting in addition to the cooperative magnetism other interesting properties according to the nature of the inserted molecules. In particular, hybrid molecular compounds containing conducting (TTF-type organic donors), bi-stable or non-linear optical species are reported.

Layered ferromagnets hosting tetraalkylammonium-substituted nitronyl nitroxide free radicals

2008

This paper describes the structural, magnetic and EPR properties of hybrid organic/inorganic magnets formed by anionic heterometallic oxalato-based layers and cationic nitronyl nitroxide (NN) free radicals of the tetraalkylammonium type. A series of compounds of formula nBu3NCH2NN[MCr(ox)3] (M = Mn (1), Ni (2), Zn (3)) has been prepared and studied by AC and DC magnetic susceptibility measurements and EPR spectroscopy. Magnetic order with critical temperatures ranging from 5 K to 15 K was confirmed. EPR measurements show that the organic spin carriers interact significantly with the inorganic network.

Toward multifunctional single-molecule magnets: characterization of dodecanuclear manganese complexes by electrospray ionization mass spectrometry.

2001

Single-molecule magnets (SMM) based on the dodecanuclear manganese complexes Mn12O12(RCOO)16 can be readily characterized by electrospray ionization mass spectrometry. This facilitates the synthesis of complex multifunctional molecules that have potential use in the organization of SMM into films or surfaces.

Slow relaxation of the magnetization, reversible solvent exchange and luminescence in 2D anilato-based frameworks.

2020

A series of multifunctional 2D frameworks prepared with Dy(iii) and the bromanilato ligand, formulated as: [Dy2(C6O4Br2)3(G)n]·nG with G = H2O, dimethylformamide (dmf) and dimethylsulfoxide (dmso), can exchange the coordinated and non-coordinated solvent molecules (G) in a reversible way. These multifunctional frameworks show field induced slow relaxation of the magnetization and luminescence that can be easily and reversibly modified by solvent exchange.

Antiferromagnetic porous metal-organic framework containing mixed-valence [Mn(II)4Mn(III)2(μ4-O)2]10+ units with catecholase activity and selective g…

2012

A multifunctional porous metal organic framework based on mixed-valence hexa-nuclear [Mn(III)(2)Mn(II)(4)O(2)(pyz)(2)(C(6)H(5)CH(2)COO)(10)] (pyz = pyrazine) units has been synthesized. The complex has been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis, and variable-temperature magnetic measurements. The structural analysis reveals that the bidentate pyz molecules connect each [Mn(6)] unit to its four [Mn(6)] neighbors through the peripheral Mn(II) centers, giving rise to a three-dimensional (3D) distorted diamond-like porous framework. Variable-temperature (2-300 K) magnetic susceptibility measurements show the presence of dominant antiferr…

An Open-Shell Coronoid with Hybrid Chichibabin-Schlenk Conjugation.

2021

A hexaradicaloid molecule with alternating Kekule and non-Kekule connectivities between adjacent spin centers was obtained by fusing two conjugation motifs in Chichibabin and Schlenk hydrocarbons into a coronoid structure. 1 H NMR, ESR, and SQUID experiments and computational analyses show that the system has a singlet ground state with a significant hexaradicaloid character (γ0 =0.826, γ1 =γ2 =0.773). It has multiple thermally accessible high-spin states (up to the septet), with uniform energy gaps of ca 1.0 kcal mol-1 between consecutive multiplicities. In line with its open-shell character, the coronoid has a small electronic band gap (ca. 0.8 eV) and undergoes two consecutive one-electr…

One‐Pot Synthesis of Superparamagnetic CoO‐MCM‐41 Nanocomposites with Uniform and Highly Dispersed Magnetic Nanoclusters

2004

Superparamagnetic CoO-MCM-41 mesoporous nanocomposites, with variable cobalt amounts, in the form of well-dispersed CoO-like clusters, were prepared in a large compositional range by a one-step reproducible procedure employing co-hydrolysis and co-condensation of the inorganic precursors in a water/triethanolamine medium. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

New coordination polymer based on a triply bridged dicarboxylate ligand: Synthesis, structure, and magnetic properties of the adipato complex [Cu4(bp…

2007

International audience; One-pot reaction of copper(II) chloride dihydrate CuCl2 · 2H2O with 2,2′-bipyridyl (bpy = C10H8N2) in the presence of sodium adipate Na2adip (adip2− = [O2C(CH2)4CO2]2−) and potassium 1,1,3,3-tetracyano-2-ethoxypropenide (tcnoet− = [(NC)2CC(OEt)C(CN)2]−) gives the new compound [Cu4(bpy)4(adip)3](tcnoet)2 · 2H2O (1), which was characterized by single crystal X-ray diffraction analysis. The Cu(II) metal ion presents an elongated square pyramidal CuN2O3 environment, with an oxygen atom in apical position and a base plane involving almost equivalent bond lengths. The structure can be described as a pseudo dinuclear species in which two Cu(bpy) units are triply bridged by …

Guidelines to design new spin crossover materials

2010

International audience; This review focuses on new families of spin crossover (SCO) complexes based on polynitrile anions as new anionic ligands or on polyazamacrocycles as neutral macrocyclic ligands. We have shown that the structural and electronic characteristics (original coordination modes and high electronic delocalization) of the polynitrile anions can be tuned by slight chemical modifications such as substitution of functional groups or variation of the negative charge to design new discrete or polymeric SCO systems.In our ongoing work on the design of new molecular systems based on new ligands that can be fine-tuned via chemical modifications, another promising way which has been r…

A new linear double phenoxide-bridged trinuclear Cu(II) Schiff base complex: Synthesis, crystallographic elucidation, magneto-structural correlation …

2014

Abstract The tetradentate (ONNO) donor Schiff base ligand LH2, derived from the condensation of salicylaldehyde and 1,3-diaminopropane, has been synthesized and reacted with CuBr2 to yield a trinuclear complex with the molecular formula [Cu3L2Br2]. Single crystal X-ray diffraction study reveals that the two terminal copper atoms adopt a square pyramidal geometry, whereas the central copper atom, situated at the inversion centre, is surrounded by four phenoxide oxygen atoms in a square planar fashion. Variable temperature magnetic susceptibility measurement study shows strong antiferromagnetic intra-trimer interactions between the copper centers with a J value of −302 cm−1. EPR study of the …

Playing with different metalloligands [NiL] and Hg to [NiL] ratios to tune the nuclearity of Ni(II)–Hg(II) complexes: Formation of di-, tri-, hexa- a…

2015

Abstract Five new hetero-metallic nickel(II)–mercury(II) complexes, [(NiL1)HgCl2] (1), [(NiL1)2HgCl2] (3), [(NiL1)2Hg(N3)2] (4), [{(NiL2)2Hg(N3)(μ1,1-N3)}2] (5) and [{(NiL2)2Hg(N3)(μ1,1-N3)HgCl2}2{Hg(N3)(μ1,1-N3)}] (6) have been synthesized by reacting metalloligands [NiL1] or [NiL2] (where H2L1 is N,N′-bis(salicylidene)-1,2-ethylenediamine and H2L2 is N,N′-bis(salicylidene)-1,3-propanediamine) with HgX2 (X− = Cl− or N3−) at different molar ratios. All five complexes have been characterised by X-ray single-crystal structural, elemental and spectroscopic analyses. In complex 1, the Hg(II) ion is coordinated to two phenoxido oxygen atoms of one [NiL1] moiety and two terminal chloride ions to …

The Crucial Role of Polyatomic Anions in Molecular Architecture: Structural And Magnetic Versatility of Five Nickel(II) Complexes Derived from A N,N,…

2009

Five new nickel(II) complexes [Ni(2)L(2)(N(3))(2)(H(2)O)(2)] (1), [Ni(2)L(2)(NO(3))(2)] (2), [Ni(2)L(2)(O(2)CPh)(CH(3)OH)(2)]ClO(4).0.5CH(3)OH (3), [Ni(3)L(2)(O(2)CPh)(4)] (4), and [Ni(2)L(2)(NO(2))(2)](n) (5) have been synthesized by using a tridentate Schiff base ligand, HL (2-[(3-Methylamino-propylimino)-methyl]-phenol), and the polyatomic monoanions N(3)(-), NO(3)(-), PhCOO(-), or NO(2)(-). The complexes have been structurally and magnetically characterized. The structural analysis reveals that in all five complexes, the Ni(II) ions possess a distorted octahedral geometry. Complexes 1 and 2 are dinuclear with di-mu-1,1-azido and di-mu(2)-phenoxo bridges, respectively. Complex 3 is also …

Isolation of Two Different Ni2Zn Complexes with an Unprecedented Cocrystal Formed by One of Them and a “Coordination Positional Isomer” of the Other

2013

A new homometallic trinuclear Ni(II) complex [(NiL)2Ni(NCS)2] (1) and three heterometallic trinuclear Ni(II)-Zn(II)-Ni(II) complexes [(NiL)2Zn(NCS)2] (2), [(NiL)2Zn(NCS)2(CH3OH)2]·2CH3OH (3) and {[(NiL)2Zn(NCS)2(CH3OH)2]} {[(NiL)2Zn(NCS)2]} (4) have been synthesized by using the "complex as ligand" approach with the "metalloligand" [NiL] (H2L = N,N'-bis(salicylidene)-1,3-propanediamine) and thiocyanate in different ratios. All the complexes have been structurally and magnetically characterized. In the isomorphous complexes 1 and 2, the two terminal square planar Ni atoms and the central octahedral nickel atom (in 1) or zinc atom (in 2) are arranged in a bent structure where two cis κN-SCN(-…

An unprecedented CuII–Schiff base complex existing as two different trinuclear units with strong antiferromagnetic couplings

2009

Abstract A new tetradentate N 2 O 2 donor Schiff base ligand [OHC 6 H 4 CH NCH 2 CH 2 CH(CH 2 CH 3 )N CHC 6 H 4 OH =  H 2 L ] was obtained by 1:2 condensation of 1,3-diaminopentane with salicylaldehyde and has been used to synthesise an unusual copper(II) complex whose asymmetric unit presents two structurally different almost linear trinuclear units [Cu 3 (μ- L ) 2 (ClO 4 ) 2 ] [Cu 3 (μ- L ) 2 (H 2 O)(ClO 4 ) 2 ] ( 1 ). The ligand and the complex were characterised by elemental analysis, FT-IR, 1 H NMR and UV–Vis spectroscopy in addition electrochemical and single crystal X-ray diffraction studies were performed for the complex. The magnetic properties of 1 reveal the presence of strong in…

Halo and Pseudohalo Cu(I)-Pyridinato Double Chains with Tunable Physical Properties

2015

The properties recently reported on the Cu(I)-iodide pyrimidine nonporous 1D-coordination polymer [CuI(ANP)] (ANP = 2-amino-5-nitropyridine) showing reversible physically and chemically driven electrical response have prompted us to carry a comparative study with the series of [CuX(ANP)] (X = Cl (1), X = Br (2), X = CN (4), and X = SCN (5)) in order to understand the potential influence of the halide and pseudohalide bridging ligands on the physical properties and their electrical response to vapors of these materials. The structural characterization of the series shows a common feature, the presence of -X-Cu(ANP)-X- (X = Cl, Br, I, SCN) double chain structure. Complex [Cu(ANP)(CN)] (4) pre…

Formation of a dinuclear and a trinuclear Ni(II) complex on slight variation of experimental conditions: Structural analysis and magnetic properties

2017

Abstract A diphenoxido bridged dinuclear Ni(II) complex [Ni2L2(NO2)2] (1) and a μ2 and μ3-phenoxido, μ3-hydroxido, and μ2-nitrito (1κO:2κN) bridged trinuclear Ni(II) complex [Ni3L3(OH)(NO2)]·ClO4 (2), have been synthesized using a tridentate reduced Schiff base ligand HL (HL = 2-[(2-dimethylamino-ethylamino)-methyl]-phenol). Both complexes were characterized by X-ray structure determination and variable-temperature magnetic susceptibility measurements. In both complexes the nickel atoms are six-coordinated with a distorted octahedral environment. The interesting feature of the trimeric complex 2 is that the three mononuclear units are assembled around a μ3-hydroxido ion in such a way that t…

Synthesis, Structure, and Magnetic Properties of the Oxalate-Based Bimetallic Ferromagnetic Chain {[K(18-crown-6)][Mn(H2O)2Cr(ox)3]}∞ (18-crown-6 = C…

2005

The salt [K(18-crown-6)][Mn(H2O)2Cr(ox)3]·0.5(18-crown-6) (1) has been prepared and structurally and magnetically characterized. It crystallizes in the P21/c space group [a = 21.011(2) A, b = 11.265(2) A, c = 15.748(3) A, β = 105.952(6)°, V = 3584(1) A3, and Z = 4] and contains [Mn(H2O)2Cr(ox)3]∞ chains connected through hydrogen bonding to form 2D anionic networks. The magnetic exchange is ferromagnetic [J = +2.23(2) cm-1] in the chain and also in between chains, reaching bulk ferromagnetic ordering below 3.5 K.

ChemInform Abstract: Electrical Conductive Coordination Polymers

2012

Coordination polymers are currently one of the hottest topics in Inorganic and Supramolecular Chemistry. This critical review summarizes the current state-of-the-art on electrical conductive coordination polymers (CPs), also named metal–organic frameworks (MOFs). The data were collected following two sort criteria of the CPs structure: dimensionality and bridging ligands (151 references).

Experimental and Theoretical Study of Dynamic Structural Transformations between Sensing Copper(II)-Uracil Antiferromagnetic and Metamagnetic Coordin…

2020

This paper describes the synthesis and characterization of several Copper(II)-uracil-1-propionic acid (UPrOH) coordination compounds, including the theoretical and experimental study of their cryst...

Synthesis of a Hydrothermally Stable, Periodic Mesoporous Material Containing Magnetite Nanoparticles, and the Preparation of Oriented Films

2006

Magnetite nanoparticles modified covalently with triethoxysilane having a quaternary dicetyl ammonium ion are used together with tetraethylorthosilicate as building blocks to prepare a mesoporous material. Cetyltrimethylammonium bromide is used as a structure-directing agent under conditions typically used for mesoporous MCM-41 silicas. The resulting mesoporous material (MAG-MCM-41), containing up to 15 wt % of magnetite is characterized by transmission electron microscopy (TEM), isothermal gas adsorption, and X-ray diffraction. In contrast to siliceous MCM-41, mesoporous MAG-MCM-41 exhibits a remarkable hydrothermal stability. The magnetic properties of MAG-MCM-41 are characterized by DC a…

Late-Stage Modification of Electronic Properties of Antiaromatic and Diradicaloid Indeno[1,2-b]fluorene Analogues via Sulfur Oxidation

2020

The ability to alter optoelectronic and magnetic properties of molecules at a late stage in their preparation is in general a nontrivial feat. Here, we report the late-stage oxidation of benzothiop...

Group 10 Metal Benzene-1,2-dithiolate Derivatives in the Synthesis of Coordination Polymers Containing Potassium Countercations

2017

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.inorgchem.7b01775

Synthesis, molecular and electronic structure of an incomplete cuboidal Re 3S 4 cluster with an unusual quadruplet ground state

2012

3 pags, 3 figs, 1 tab

High nuclearity magnetic clusters: Magnetic properties of a nine cobalt cluster encapsulated in a polyoxometalate, [Co9(OH)3(H2O)6(HPO4)2(PW9O34)3]16⊕

1994

Supramolecular diversity and magnetic properties of novel heterometallic Cu(II)/Cr(III) complexes prepared from copper powder, Reineckes salt and eth…

2009

Abstract Three novel heterometallic complexes [Cu(en) 2 Cr(NCS) 4 (NH 3 ) 2 ][Cr(NCS) 4 (NH 3 ) 2 ] · 6dmf ( 1 ), [Cu(en) 2 Cr(NCS) 4 (NH 3 ) 2 ](OAc) ( 2 ) and [{Cu(en) 2 } 3 {Cr(NCS) 4 (NH 3 ) 2 } 2 (NCS) 2 ](NCS) 2 ( 3 ) have been synthesized in a one-pot reaction from copper powder, Reineckes salt, NH 4 X [X −  = OAc − ( 2 ), NCS − ( 3 )] in a dmf ( 1 ) or CH 3 CN ( 2 , 3 ) solution of ethylenediamine (en). X-ray studies showed that 1 and 2 consist of cationic polymeric chains, formed by Cu ( en ) 2 2 + and Cr ( NCS ) 4 ( NH 3 ) 2 - building blocks that bridged through thiocyanate anions. In both complexes, distinct hydrogen bonds are present and serve to increase the dimensionality of …

A novel paramagnetic molecular superconductor formed by bis(ethylenedithio)tetrathiafulvalene, tris(oxalato)ferrate(iii) anions and bromobenzene as g…

2005

The new paramagnetic molecular superconductor ET4[(H3O)Fe(C2O4)3]·C6H5Br (1) (Tc = 4.0 K) contains layers of superconducting ET donors alternating with paramagnetic hexagonal layers formed by (H3O)+, [Fe(C2O4)3]3− and guest C6H5Br molecules located in the hexagonal cavities. Conductivity measurements show metallic behavior from room temperature with a minimum in the resistivity at ca. 50 K followed by a smooth increase and a sharp drop in the resistivity with an onset at 4.0 K and a zero resistance at ca. 1.0 K. Magnetoresistance measurements indicate that Hc1 is about 7 mT and that Hc2 is very anisotropic (Hc2⊥ ≥ 5.5 T and Hc2|| ≈ 0.5 T). Magnetic susceptibility measurements show the expec…

A novel polynitrile ligand with different coordination modes: Synthesis, structure and magnetic properties of the series [M(tcnoprOH)2(H2O)2] (M=Mn, …

2008

International audience; A novel polynitrile ligand (tcnoprOH− = [(NC)2CC(OCH2CH2CH2OH)C(CN)2]−) with up to five potentially coordinating groups has been synthesized in a one-pot reaction from a cyclic acetal and malononitrile. The combination of this novel ligand with different transition metal ions has led to the synthesis of two different structural types with the same formula but with different coordination modes in the ligand. Mn(II) and Cu(II) lead to a μ2-N,O-coordinating mode in the series of compounds formulated as [M(N,O-tcnoprOH)2(H2O)2] (M = MnII (1) and CuII (2)), whereas Co(II) and, most probably Ni(II), lead to a μ2-N,N′-coordinating mode in [Co(N,N′-tcnoprOH)2(H2O)2] (3). Bot…

Synthesis, Crystal Structure, and Properties of Multicomponent Bis(ethylenedithio)tetrathiafulvalene Charge-Transfer Salts of the [Mo3S7Br6]2- Cluster

2005

A new family of bis(ethylenedithio)tetrathiafulvalene (ET) radical salts has been prepared in the presence of a triangular molybdenum sulfide cluster of formula [Mo 3 S 7 Br 6 ] 2 - , which contains highly electrophilic axialsulfur atoms. A systematic change in the experimental conditions yields five different salts, namely (ETA)2(ET B )[Mo 3 S 7 Br 6 ] 2 . CH 2 Br 2 (1), (ETA)(ET B )Mo 3 S 7 Br 6 ].1.1CH 2 Br 2 (2), (ETA)(ETB)(ET C ){[Mo 3 S 7 Br 6 ]Br}.0.5C 2 H 4 Cl 2 (3), (ET)((n-Bu 4 )N)-[Mo 3 S 7 Br 6 ] (4), and (ET)(Ph4P)[Mo 3 S 7 Br 6 ].0.5CH 3 CN (5), where the ET subscript denotes crystallographically independent molecules. The five compounds have been structurally characterized, a…

Mo 3 Q 7 (Q = S, Se) Clusters Containing Dithiolate/Diselenolate Ligands: Synthesis, Structures, and Their Use as Precursors of Magnetic Single‐Compo…

2013

The coordination chemistry of dithiolene and diselenolene ligands towards the all-selenium [Mo3Se7Br6]2– dianion has been investigated. Complexes (nBu4N)2[Zn(dmit)2] (dmit = 1,3-dithia-2-thioxo-4,5-dithiolate) and (nBu4N)2[Zn(dsit)2] (dsit = 1,3-dithia-2-thioxo-4,5-diselenolate) were employed as ligand precursors. The (nBu4N)2[Zn(dmit)2] complex in acetonitrile at reflux showed unexpected reactivity with [Mo3Se7Br6]2– dianion in which the inner Se atoms were replaced by S (all but the μ3-Se atom) to afford a series of mixed chalcogen [Mo3Se7–xSx(dmit)3]2– (x = 0–6) dianions. Reaction of the [Mo3S4Se3Br6]2– dianion with (nBu4N)2[Zn(dmit)2] under similar conditions also produced a mixed dmit-…

Sterically-controlled nuclearity in new copper(II) complexes with di-compartmental ligands: Formation of antiferromagnetically coupled angular trimer…

2010

Abstract Two new copper(II) complexes, [Cu3(L1)2(H2O)2](ClO4)2 (1) and [CuL2 ⊂ (H2O)] (2) have been derived from two di-compartmental Schiff base ligands H2L1 and H2L2, respectively. Depending on slight modification of the substituent group of the potentially N2O4 donor ligands, tri- and mononuclear structures are obtained, which have been confirmed by single-crystal X-ray diffraction studies. Both complexes have been characterized by elemental analysis, IR, UV–vis and EPR spectroscopy. Complex 1 consists of an angular trinuclear array of copper ions, while complex 2 consists of a mononuclear copper center. Variable temperature magnetic susceptibility measurements have been performed to inv…

Structural and magnetic studies of tetranuclear heterometallic M/Cr (M = Co, Mn) complexes self-assembled from zerovalent cobalt or manganese, Reinec…

2010

Abstract Four novel heterometallic complexes [Co2Cr2(NCS)4(HDea)2(Dea)2]·4dmf (1), [Co2Cr2(NCS)4(HDea)2(Dea)2]·4dmso (2), [Mn2Cr2(NCS)4(HDea)2(Dea)2(dmf)2]·2dmf (3) and [Mn2Cr2(NCS)4(HDea)2(Dea)2(dmso)2]·4dmso (4) have been prepared using zerovalent cobalt (1, 2) or manganese (3, 4), Reineckes salt, ammonium thiocyanate and a non-aqueous solution of diethanolamine (H2Dea) in air. The single X-ray analysis reveals that all compounds have similar centrosymmetric crystal structures based on a tetranuclear {M2Cr2(μ3-O)2(μ-O)4} (M = Co, Mn) core. Variable-temperature magnetic susceptibility measurements of 1, 2 and 4 show antiferromagnetic coupling between the magnetic centers, while 3 exhibits …

[MnM(egta)]. 8H2 = (M = Mn, Cd): Verbindungen mit einem neuartigen zweidimensionalen magnetischen Gitter

1993

Magnetochemistry: An Old Discipline with New Opportunities

2015

Even if the moment is not featured in “Youtube” and the story might have not been exactly as we have been told, we can easily imagine the surprise of the Cretan shepherd named Magnes when he observed for the first time that a black stone in the region of Magnesia (in northern Greece) attracted the iron tip of his crook almost 4000 years ago. [...]

Magnetic properties of hybrid molecular materials based on oxalato complexes

2003

Abstract The use of [MIII(ox)3]3− (MIII=Ru, Rh) complexes as building blocks for hybrid molecular materials is highlighted with two different synthetic approaches. The first strategy is the combination of organic donors and [RuIII(ox)3]3− units, resulting in the radical salt of formula TTF3[Ru(ox)3]·0.5EtOH·4H2O (1) which shows coexistence of paramagnetism and semiconducting properties. The second approach is the synthesis of extended 2D bimetallic oxalato-bridged networks of general formula [FeCp2 *][MIIRh(ox)3] in which paramagnetic layers of decamethylferricinium cations are alternated with paramagnetic bimetallic layers.

Molecular Magnetic Materials from Polyoxometalates

1994

The significance of polyoxometalates in the field of molecular magnetism is discussed. We show that this kind of inorganic complexes provides remarkable examples for the study of the exchange interactions in clusters. On the other hand, we examine the possibility of using these metal oxide anions as magnetic components of molecular materials containing organic tetrathiafulvalenes as electron donor molecules.

Spin crossover phenomenon of a semi-fluorinated iron (II) complex organized in a Langmuir–Blodgett film

2000

Abstract A new amphiphilic iron (II) complex bearing semi-fluorinated chains has been organized in Langmuir and Langmuir–Blodgett (LB) films. This molecule forms a perfectly stable monolayer at the gas–water interface. Such a film can be transferred easily onto a solid substrate leading to well-defined multilayers. The spin crossover phenomenon occurring in this material has been studied by infrared spectroscopy and magnetization measurements. In the LB film architecture, the iron complex appears to be quenched in a high spin state. This quenching can be released after a thermal annealing and is therefore associated to the specific organization induced by the LB technique.

Multifunctional coordination polymers based on copper with modified nucleobases, easily modulated in size and conductivity.

2019

This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo period

Increasing the Ordering Temperatures in Oxalate-Based 3D Chiral Magnets:  the Series [Ir(ppy)2(bpy)][MIIMIII(ox)3]·0.5H2O (MIIMIII = MnCr, FeCr, CoCr…

2006

The synthesis, structure, and physical properties of a novel series of oxalate-based bimetallic magnets obtained by using the Ir(ppy)2(bpy)]+ cation as a template of the bimetallic [MIIMIII(ox)3]- ...

Hexanuclear NiII4LnIII2 Complexes with SMM Behavior at Zero Field for Ln = Tb, Dy, Ho

2020

A mononuclear Ni(II) complex, [NiL2]·2H2O, was prepared by the reaction of a N2O2 donor monocondensed Schiff base ligand, 2-((3-aminopropylimino)methyl)-6-methoxyphenol (HL), with NiCl2·6H2O. The reaction of this complex with NiCl2·6H2O and LnCl3·6H2O (Ln = Gd, Tb, Dy, Ho) in a 1:1:1 molar ratio leads to four hexanuclear Ni4Ln2 complexes formulated as [{(NiL)2Gd}2(μ2-Cl)2(μ3-OH)4(OH2)4]Cl4·CH3CN·H2O (1), [{(NiL)2Tb}2(μ2-Cl)2Cl2(μ3-OH)4(OH2)2]Cl2·12H2O (2), [{(NiL)2Dy}2(μ2-Cl)2Cl2(μ3-OH)4(OH2)2]Cl2·16H2O (3), and [{(NiL)2Ho}2(μ2-Cl)2(μ3-OH)4(OH2)4]Cl4·CH3CN·1.8H2O (4). The Ln(III) centers are octacoordinated with a triangular-dodecahedral geometry, and the geometries around the Ni(II) center…

Conductive Hybrid Films of Polyarylamine Electrochemically Oxidized with the Molecular Nanomagnet [Mn12O12(H2O)4-(C6F5COO)16]

2005

Azide, water and adipate as bridging ligands for Cu(II): Synthesis, structure and magnetism of (μ4-adipato-κ-O)(μ-aqua)(μ-azido-κN1,N1)copper(II) mon…

2016

The Distinguished Scientist Fellowship Program (DSFP) at King Saud University is gratefully acknowledged. The authors are grateful to the Algerian MESRS (Ministère de l’Enseignement Supérieur et de la Recherche Scientifique), the Université Ferhat Abbas Sétif 1, the KSU DSFP program and the Spanish MINECO (CTQ2014-52758-P and MAT2014-56143-R) and the Generalitat Valenciana (PrometeoII/2014/076) for financial support. The synthesis, characterization, single crystal structure and magnetic properties of the compound [(CuN3(OH2))2(adp)]n (1) are presented, in which adp stands for the adipate(2-) anion. This compound consists of layers containing chains of six-coordinated Cu(II) ions; the chains…

Recent advances in polyoxometalate-containing molecular conductors

2005

The recent advances in crystalline conducting molecular materials based on polyoxometalates (POMs) and organic donors of the tetrathiafulvalene (TTF) family or perylene are discussed. We emphasise the wide diversity of POM structural types and the variety of packing architectures for the organic molecules that can be induced by these inorganic anions. Besides structural effects, we show that these hybrids can have interesting electric and/or magnetic properties. Thus, in the last years the common belief that this type of radical salts containing such big and highly charged anions could only exhibit poor conducting properties has been refuted by the production of new materials exhibiting hig…

Structure and Magnetic Properties of the Ferromagnetic Cu3Cl126- Trimer in [(NH3C2H4)3NH]2Cu3Cl14

2004

The crystal structure consists of a strongly hydrogen bonded network of tris(N-ethylammonium)ammonium cations, Cu3Cl12(6)- trimeric species, and Cl- anions. The Cu3Cl12(6)- trimers are formed by two distorted tetrahedral CuCl4(2)- anions linked to a central square planar CuCl4(2)- anion via semicoordinate Cu-Cl...Cu mu1 bridges. The central copper ion shows only small deviations from ideal D4h symmetry, while the terminal copper ions show a mild distortion from D2d symmetry with an average trans Cl-Cu-Cl angle of 136.0 degrees. The semicoordinate linkages provide a ferromagnetic exchange pathway between the copper ions with J/k = 6.91(3) K. Short Cl...Cl contacts (3.67-3.90 angstoms) lead t…

Nickel precursors based on diamagnetic and paramagnetic di(imine)pyridine ligands for magnetic materials: Synthesis, X-ray structures and magnetic st…

2018

International audience; Structural characterization and spectroscopic studies of the (2-acetyl-6-(1-TEMPO-imino)ethyl)pyridine (pat) and the 2,6-bis(1-TEMPO-imino)ethyl)pyridine (pbtMe) ligands are presented. Their electrochemical properties are also discussed. Two new nickel complexes, [NiII(dip)(CH3CN)(H2O)2](BF4)2 (1) (dip = 2,6-(di-iminepyridine)) and [NiII(pbtMe)(CH3CN)3](BF4)2 (2) have been characterized by X-ray diffraction. The reaction of 1 with the tetraethyl ammonium pentacyanopropenide salt (Et4N)(pcp) affords the new compound [NiII(pcp)(dip)(CH3CN)](pcp) (3) for which X-ray diffraction studies evidence an usual bridging μ2 coordination mode for the pentacyanopropenide anion, le…

Polyoxometalate salts of cationic nitronyl nitroxide free radicals

2008

The cationic nitronyl nitroxide free radical of the N-methylpyridinium type p-MepyNN + has been combined with [Mo 8 0 26 ] 4- and Keggin [SiW 12 0 40 ] 4- polyanions to afford salts ( p-MepyNN) 4 [Mo 8 0 26 ] DMSO (DMSO = dimethylsulfoxide) (1) and (p-MepyNN)4[SiW 12 0 40 ] 6DMF (DMF = dimethylformamide) (2). Herein, their structural and magnetic properties are described.

Nickel(II) 3,4;9,10-perylenediimide bis-phosphonate pentahydrate: A metal-organic ferromagnetic dye

2012

The new metal organic compound nickel(II) 3,4;9,10-perylenediimide bis-phosphonate pentahydrate, i.e. Ni-2[(PDI-BP)-(H2O)(2)]center dot 3H(2)O (1), has been synthesized and its structural and magnetic properties have been studied. Reaction of 3,4;9,10-perylenediimide bisphosphonate (PDI-BP, hereafter) ligand and nickel chloride in water resulted in the precipitation of a red and poorly crystalline solid (1). As the solid shows a poor crystalline organization of aggregates, the energy dispersive X-ray diffraction analysis (EDXD) technique has been used to obtain short-range order structural information of the single nanoaggregates by radial distribution function analysis. The overall structu…

[Cu(tn)]3[Cr(CN)6]2·3H2O: A unique two-dimensional Cu-Cr cyano-bridged ferromagnet (tn = 1,3-diaminopropane)

2002

Reaction of the two-coordinate ‘assembling complex-ligand’ [Cu(tn)]2+ with the building block [Cr(CN)6]32 leads to a unique two-dimensional Cu–Cr cyano-bridged ferromagnet with unusual m3- and m4-bridging [Cu(tn)]2+ units. Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es

Layered Molecule-Based Magnets Formed by Decamethylmetallocenium Cations and Two-Dimensional Bimetallic Complexes [MIIRuIII(ox)3]−(MII=;Mn, Fe, Co, C…

2001

Abstract A new series of hybrid organometallic-inorganic layered magnets with formula [Z III Cp * 2 ] [M II Ru III (ox) 3 ] ( Z III =Co and Fe; M II =Mn, Fe, Co, Cu, and Zn; ox=oxalate: Cp * =pentamethylcyclopentadienyl) has been prepared. All of these compounds are isostructural to the previously reported [ Z III Cp * 2 ] [ M II M III (ox) 3 ] ( M III =Cr, Fe) series and crystallize in the monoclinic space group C 2/ m , as found by powder X-ray diffraction analysis. They are novel examples of magnetic materials formed by bimetallic oxalate-based extended layers separated by layers of organometallic cations. The magnetic properties of all these compounds have been investigated (ac and dc m…

Ferromagnetic exchange coupling in a new bis(μ-chloro)-bridged copper(II) Schiff base complex: Synthesis, structure, magnetic properties and catalyti…

2009

Abstract A new (μ-chloro)-bridged complex [Cu(HL)Cl]2 · H2O (1) with the Schiff base ligand H2L, [2-((E)-(2-hydroxyethylimino)methyl)-4-bromophenol], has been synthesized and characterized by elemental analysis, IR, UV–Vis and EPR spectroscopic studies. X-ray diffraction studies show that 1 is a binuclear CuII complex with a pair of chlorine atoms bridging the copper atoms in a central Cu2Cl2 core. Each copper atom in 1 adopts a distorted square-pyramidal geometry with the imine nitrogen atom, alkoxy and phenoxy oxygen atoms from the Schiff base ligand and a bridging chlorine atom constructing the basal plane, while the apical position of the pyramid is occupied by the other bridging chlori…

The Series of Molecular Conductors and Superconductors ET4[AFe(C2O4)3]·PhX (ET = bis(ethylenedithio)tetrathiafulvalene; (C2O4)2– = oxalate; A+ = H3O+…

2011

An extensive series of radical salts formed by the organic donor bis(ethylenedithio)tetrathiafulvalene (ET), the paramagnetic tris(oxalato)ferrate(III) anion [Fe(C(2)O(4))(3)](3-), and halobenzene guest molecules has been synthesized and characterized. The change of the halogen atom in this series has allowed the study of the effect of the size and charge polarization on the crystal structures and physical properties while keeping the geometry of the guest molecule. The general formula of the salts is ET(4)[A(I)Fe(C(2)O(4))(3)]·G with A/G = H(3)O(+)/PhF (1); H(3)O(+)/PhCl (2); H(3)O(+)/PhBr (3), and K(+)/PhI (4), (crystal data at room temperature: (1) monoclinic, space group C2/c with a = 1…

New, Multi‐Dimensional Cu(tn)‐[M(CN) 6 ] n – Cyano‐Bridged, Bimetallic Coordination Materials (M = Fe II , Co III , Cr III and tn = 1,3‐Diaminopropan…

2005

Reaction of the [Fe I I I (CN) 6 ] 3 - anion with [Cu I I (tn)(H 2 O) n ] 2 + (tn = 1,3-diaminopropane) affords the compounds [{Cu I I (tn)} 2 -{Fe I I (CN) 6 }].KCl.5H 2 O (1), [(Cu"(tn))2(Fe"(CN) 6 )].4H 2 O (2), and [{Cu I I (tnH) 2 (H 2 O) 2 }{Fe I I (CN) 6 }].2H 2 O (3). Each iron center in 1 and 2 is linked to six copper(II) ions by six cyanide bridges, while each copper ion is linked to three equivalent iron(II) ions. Despite these resemblances, the two compounds present large structural differences caused by two different orientations of the Cu-NC-Fe bridges: compound 1 has a 2D structure which can be described as successions of "Cu 4 Fe 3 " defective cubane units, while compound 2 …

Structure and Properties of One-Dimensional Heterobimetallic Polymers Containing Dicyanoaurate and Dirhodium(II) Fragments

2012

The synthesis and characterization of compound [Rh(2)(O(2)CEt)(4)(H(2)O)(2)] (1) and one-dimensional heterobimetallic polymers K(n){Rh(2)(O(2)CEt)(4)[Au(CN)(2)]}(n) (2) and K(n){Rh(2)(O(2)CMe)(4)[Au(CN)(2)]}(n)·4nH(2)O (3), constructed from dirhodiumtetracarboxylato units, [Rh(2)(O(2)CR)(4)](+), and dicyanoaurate, [Au(CN)(2)](-), fragments are described. In both compounds 2 and 3 the resulting polymeric chains are nonlinear and have in common similar structural parameters, although the solid state supramolecular arrangement is very different. These structural differences explain the fact that complex 2 displays aurophilic interactions while this type of interactions are absent in complex 3.…

Synthesis and magnetic characterization of trans-dichloroplatinum blues with creatinine

1992

Abstract By reaction of trans -[Pt II Cl 4 ] 2− with the amidate ligand creatinine two new paramagnetic blue platinum complexes have been obtained, namely violet and green varieties. These complexes have been characterized from thermal analysis, EPR and magnetic susceptibility. The violet complex has been formulated as trans -[Pt(creat)(H 2 O)Cl] 4 Cl. This compound has shown to be very stable, showing an extensive hyperfine structure in the powder EPR spectra. This result is a clear evidence of a tetranuclear oligomeric structure with one delocalized unpaired spin in the unit. EPR spectra in frozen solutions indicate that this mixed-valence complex maintains its oligomeric structure upon d…

Structural Diversity and Physical Properties of Paramagnetic Molecular Conductors Based on Bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and the T…

2014

International audience; Electrocrystallization of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) in the presence of the tris(chloranilato)ferrate(III) [Fe(Cl2An)3]3– paramagnetic chiral anion in different stoichiometric ratios and solvent mixtures afforded three different hybrid systems formulated as [BEDT-TTF]3[Fe(Cl2An)3]·3CH2Cl2·H2O (1), δ-[BEDT-TTF]5[Fe(Cl2An)3]·4H2O (2), and α‴-[BEDT-TTF]18[Fe(Cl2An)3]3·3CH2Cl2·6H2O (3). Compound 1 presents an unusual structure without the typical alternating organic and inorganic layers, whereas compounds 2 and 3show a segregated organic–inorganic crystal structure where layers formed by Λ and Δ enantiomers of the paramagnetic complex, together with…

A rare polymeric azido-bridged copper(II) chain with a pentameric repeating unit: Synthesis, structure and magnetic properties

2013

International audience; The novel polymeric chain copper(II) complex [Cu4(μ-Mesalpn)2(μ1,1,1-N3)2(μ1,1-N3)2Cu]n (1) was prepared by the reaction of Cu(NO3)2·3H2O with Mesalpn in the presence of an excess of NaN3. A single-crystal X-ray diffraction study showed an unusual 1D polymeric chain based on pentanuclear Cu5 units with both μ1,1,1-N3 and μ1,1-N3 bridges, and with three independent Cu(II) ions presenting three different coordination numbers (4, 5 and 6). The magnetic susceptibility data show the presence of dominant anti-ferromagnetic interactions.

Weak Interactions Modulating the Dimensionality in Supramolecular Architectures in Three New Nickel(II)-Hydrazone Complexes, Magnetostructural Correl…

2011

Three different ONO donor acetyl hydrazone Schiff bases have been synthesized from the condensation of acetic hydrazide with three different carbonyl compounds: salicylaldehyde (HL(1)), 2-hydroxyacetophenone (HL(2)), and 2, 3-dihydroxybenzaldehyde (HL(3)). These tridentate ligands are reacted with Ni(OOCCF(3))(2)·xH(2)O to yield three new Ni(II) complexes having distorted octahedral geometry at each Ni center: [Ni(L(1))(OOCCF(3))(CH(3)OH)](2) (1), [Ni(L(2))(OOCCF(3))(H(2)O)](2) (2), and [Ni(L(3))(L(3)H)](OOCCF(3))(H(2)O)(1.65)(CH(3)OH)(0.35) (3). The ligands and the complexes have been characterized by elemental analysis and IR and UV-vis spectroscopy, and the structures of the complexes ha…

New charge transfer salts of two organic π-donors of the tetrathiafulvalene type with the paramagnetic [Cr(NCS)6]3- anion

2003

cited By 9; International audience; The electrochemical combination of the paramagnetic anion [Cr(NCS)6]3- with the organic π-donors bis(ethylenedithio)tetrathiafulvalene (ET) and 4,5-bis(2-hydroxyethylthio) -4′,5′-ethylenedithiotetrathiafulvalene (DHET-EDTTTF) leads to two new radical cation salts, namely (ET)4 [Cr(NCS 6]·PhCN 1 and (DHET-EDTTTF)2 (NEt4)[Cr(NCS)6] 2. Both have been characterized by X-ray crystallography, magnetic and resistivity measurements. The structure of 1 consists of alternating inorganic layers generated by the anions and organic layers in which the PhCN molecules are inserted; the organic sub-lattice is built up from four different ET units, three of them with a ch…

Slow Relaxation of the Magnetization on Frustrated Triangular FeIII Units with S= 1/2 Ground State: The Effect of the Highly Ordered Crystal Lattice …

2021

In order to understand how the different arrangements of highly ordered triangular FeIII S = 1/2 systems with various types of diamagnetic and paramagnetic anions affect their static and dynamic magnetic properties, we have obtained by solvothermal synthesis four new μ3-oxido trinuclear FeIII compounds, [Fe3O(Ac)6(AcNH2)3][BF4]·(CH3CONH2)0.5(H2O)0.5 (1-BF4), [Fe3O(Ac)6(AcNH2)3][GaCl4] (1-GaCl4), [Fe3O(Ac)6(AcNH2)3][FeCl4] (1-FeCl4) and [Fe3O(Ac)6(AcNH2)3][FeBr4] (1-FeBr4), where, Ac- = CH3COO- and AcNH2 = CH3CONH2. The organization of the triangular units is very varied, from segregated stacks to eclipsed equilateral triangular [Fe3O]+ units along the c-axis with intercalated [MX4]- units. …

Synthesis, Crystal Structure, Thermal Analysis and Magnetic Behavior of a Novel One‐Dimensional Polymeric Pyridinium Chlorocuprate( II ): (Hpy) 2 [Cu…

2003

A one-dimensional polymeric pyridinium chlorocuprate (HPy)2[Cu3Cl8(H2O)2], an intermediate between (HPy)CuCl3 and CuCl2·2H2O, has been synthesized and characterized by X-ray analysis [monoclinic, P21/c, a = 7.8950(10), b = 14.144(2), c = 9.921(10) A, β = 99.20(2)°]. The structure contains [Cu3Cl8(H2O)2]n2n− chains in which both square-pyramidal and octahedral CuII exist. The chains are composed of linked [Cu2Cl6]2− dimers and CuCl2(H2O)2 monomeric units. On being heated in the solid state the compound undergoes dehydration followed by dehydrohalogenation to produce a pyridine complex of CuII: [Cu3Py2Cl6]. Other compounds, (HPy)2[CuCl4], CuPyCl2 and CuPy2Cl2, also produce [Cu3Py2Cl6] as an i…

A Facile Strategy to Create Electrocatalysts of Highly Dispersive Ni–Mo Sulfide Nanosheets on Graphene by Derivation of Polyoxometalate Coordination …

2021

Synthesis, structure and magnetic characterization of [Fe(bpp)2][Cu(pds)2]2·solv (solv=CH3CN and CH3OH)

2008

A novel salt of the Fe(II) cation [Fe(bpp)2]2+ (bpp = 2,6-bis(pyrazol-3-yl)pyridine) with the [CuIII(pds)2]- anion (pds = pirazine-2,3-diselenolate) formulated as [Fe(bpp)2][Cu(pds)2]2·3CH3CN has been prepared and characterized by single crystal X-ray diffraction and magnetic measurements. The salt presents a layered structure where cations and anions alternate along the b direction with many intermolecular short contacts between the cations and anions. The magnetic properties show that the Fe(II) cations [Fe(bpp)2]2+ present a high-spin S = 2 ground spin state with g = 2.073(1) and a zero field splitting (ZFS) of 7.7(1) cm-1 but no the expected spin transition at low temperatures. © 2008 E…

Crystallisation of H3BTC, H3TPO or H2SDA with MII (M = Co, Mn or Zn) and 2,2′-bipyridyl: design and control of co-ordination architecture, and magnet…

1999

The hydrothermal reaction of benzene-1,3,5-tricarboxylic acid (H3BTC) with MII (M = Mn, Co or Zn), tris(4-carboxyphenyl)phosphine oxide (H3TPO) or cis-stilbene-4,4′-dicarboxylic acid (H2SDA) with CoII and 2,2′-bipyridyl (BIPY) gave 1-D co-ordination networks formulated as: [M(HBTC)(BIPY)(H2O)] (M = Mn 1, Co 2, or Zn 3; [Co3(BTC)2(BIPY)2(H2O)6]·4H2O 4, [Co3(TPO)2(BIPY)2(H2O)6]·xH2O 5 and [Co(SDA)(BIPY)(H2O)] 6. Structures 1 and 2 consist of double stranded chains of alternating HBTC dianions and dimeric units MII–MII linked by two µ-(1,1) bridging carboxylates. Magnetic properties of 1 and 2 indicate the presence of ferromagnetic exchange interactions within the dimers. Structures 4 and 5 co…

Copper-Assisted Hemiacetal Synthesis: A Cu II Chain Obtained by a One-Step in situ Reaction of Picolinaldehyde

2014

International audience; The 1D polymer complex [Cu2(L)2(SCN)2]n (1 ) has been synthesised in a one‐step in situ reaction of picolinaldehyde with sodium thiocyanate. The complex 1 was characterised by FTIR spectroscopy, UV/Vis spectrophotometry and elemental analysis. The crystal structure of complex 1 shows that chains of dimer complexes are formed with tetra‐ and pentacoordinate copper centres alternately linked by one thiocyanato and two alkoxido bridges. Variable‐temperature magnetic measurements showed a strong antiferromagnetic interaction between the copper centres within the dimer mediated by the two alkoxido bridges with a J value of –374 cm–1, which is in agreement with the DFT‐cal…

One-dimensional and two-dimensional anilate-based magnets with inserted spin-crossover complexes.

2014

The syntheses, structures, and magnetic properties of a family of bimetallic anilate-based compounds with inserted spin-crossover cationic complexes are reported. The structures of 1-4 present a two-dimensional anionic network formed by Mn(II) and Cr(III) ions linked through anilate ligands with inserted [Fe(III)(sal2-trien)](+) (1), [Fe(III)(4-OH-sal2-trien)](+) (2), [Fe(III)(sal2-epe)](+) (3), or [Fe(III)(5-Cl-sal2-trien)](+) (4) complexes. The structure of 5 is formed by anionic [Mn(II)Cl2Cr(III)(Cl2An)3](3-) chains surrounded by [Fe(II)(tren(imid)3)](2+), Cl(-), and solvent molecules. The magnetic properties indicate that 1-4 undergo a long-range ferrimagnetic ordering at ca. 10 K. On t…

Torsional Bias as a Strategy To Tune Singlet–Triplet Gaps in Organic Diradicals

2018

Quinoidal compounds with proaromatic structures possess differing degrees of diradical character, where the open-shell diradical resonance form has restored aromaticity throughout the compound. Methods to tune the diradical character of these compounds have traditionally focused on altering the length and the molecular composition of the π-conjugated backbones. However, other molecular design strategies to tune the singlet–triplet gap of π-conjugated quinoidal molecules have not been extensively explored. We previously reported a strikingly small energy gap between the quinoidal and diradical states of a quinoidal small molecule containing methano[10]annulene (TMTQ) that was dictated in lar…

Fluoreno[2,1-a]fluorene: an ortho-naphthoquinodimethane-based system with partial diradical character.

2019

Fluoreno[2,1-a]fluorene, a molecule comprising fused ortho-quinodimethane units in a 1,5-napthoquinodimethane core, has been prepared and investigated with spectroscopy (UV-Vis-NIR, 1H-NMR and Raman), SQUID magnetometry, spectroelectrochemistry and quantum chemistry. While para-quinodimethanes with a 2,6-substitution pattern exist as closed-shell species and meta-quinodimethanes with 2,7-substitution favour a ground electronic state with very large diradical character, our 1,5-substituted ortho-naphthoquinodimethane-based system exhibits an intermediate degree of diradical character.

Spontaneous doping and magnetic properties of polyacetylene and polypropyne synthesized in situ in Ni-exchanged mordenite and mesoporous MCM-41

2001

Upon polymerisation of acetylene and propyne inside the channels of Ni2+-exchanged mordenite and mesoporous MCM-41 spontaneous doping and formation of antiferromagnetic NiO clusters are observed to various extents. The population of polarons present in the final polymer/zeolite composite: (i) is higher for polyacetylene than for polypropyne; (ii) increases with polymerisation temperature in the range 100 to 335 °C; (iii) increases with the C content; and (iv) is higher for mordenite than for MCM-41 under the same conditions. The use of Ni(0),H+-mordenite for polymer formation enhances the polaron population of the resulting polymer by over one order of magnitude. Doped polyacetylene encapsu…

Front Cover: Magnetic Bistability in Macrocycle‐Based Fe II Spin‐Crossover Complexes: Counter Ion and Solvent Effects (Eur. J. Inorg. Chem. 34/2016)

2016

Hydrogen bonding versus π-stacking in ferromagnetic interactions. Studies on a copper triazolopyridine complex

2013

Magnetic susceptibility measurements show weak ferromagnetic exchange between the copper(II) ions of a novel triazolopyridine derivative [Cu(TPT)(H2O)2(BF4)](BF4)·2H2O (TPT = 3-{6-([1,2,3]triazolo[1,5-a]pyrid-3-yl)-2-pyridyl}-[1,2,3]triazolo[1,5-a]pyridine). Mononuclear [Cu(TPT)(H2O)2(BF4)]+ entities are connected through O–H⋯F, C–H⋯F and π⋯π interactions to give a 3D framework. Ferromagnetic properties are discussed on the basis of the interactions network.

Intercalation of decamethylferrocenium cations in bimetallic oxalate-bridged two-dimensional magnets

1997

The structure and magnetic properties of novel hybrid molecule-based magnets formed by combination of two magnetically active sublattices, the bimetallic oxalatobridged honeycomb net [MnIIMIII(ox)3] (MII = Mn, Fe, Co, Cr, Ni, Cu; MIII = Cr, Fe) and the organometallic cation decamethylferrocenium, are reported. Clemente Leon, Miguel, Miguel.Clemente@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es ; Galan Mascaros, Jose Ramon, Jose.R.Galan@uv.es ; Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es

Inside Cover: An Unusually Small Singlet-Triplet Gap in a Quinoidal 1,6-Methano[10]annulene Resulting from Baird’s 4nπ-Electron Triplet Stabilization…

2015

A chiral molecular conductor: synthesis, structure, and physical properties of [ET]3[Sb2(L-tart)2].CH3CN (ET = bis(ethylendithio)tetrathiafulvalene; …

2004

The salt [ET](3)[Sb(2)(L-tart)(2)].CH(3)CN (1) has been obtained by electrocrystallization of the organic donor bis(ethylendithio)tetrathiafulvalene (ET or BEDT-TTF) in the presence of the chiral anionic complex [Sb(2)(L-tart)(2)](2-) (L-tart = (2R,3R)-(+)-tartrate). This salt crystallizes in the chiral space group P2(1)2(1)2(1) (a = 11.145(2) angstroms, b = 12.848(2) angstroms, c = 40.159(14) angstroms, V = 5750.4(14) angstroms(3), Z = 4) and is formed by alternating layers of the anions and of the organic radicals in a noncentrosymmetric alpha-type packing. This compound shows a room temperature electrical conductivity of approximately 1 S.cm(-1) and semiconducting behavior with an activa…

Asymmetric and Symmetric Dicopper(II) Paddle-Wheel Units with Modified Nucleobases

2015

New copper(II) paddle-wheel complexes with different modified nucleobases and simple molecules in the axial positions have been prepared by direct reactions between copper(II) salts and the corresponding uracil- or thymine-1-acetic acids under inert atmosphere to produce the two homoleptic complexes, [Cu2(μ-OOCCH2-T)4(G)2] and [Cu2(μ-OOCCH2-U)4(G)2], and the heteroleptic one [Cu2(μ-OOCCH2-T)2(μ-OOCCH2-U)2(G)2] (where OOCCH2-T = thymine-1-acetate, OOCCH2-U = uracil-1-acetate, and G = dimethylformamide, water, dimethylacetamide, or dimethyl sulfoxide). Interestingly, the crystal structures of this family of closely related molecules present significant differences in their supramolecular arra…

Comparison among superconducting models for β″-ET4[(H3O)Fe(C2O4)3]·C6H5Br single crystals by scanning tunnelling spectroscopy

2008

Single crystals of the novel superconductor beta ''-(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]center dot C6H5Br charge-transfer salt were studied using a scanning tunnelling microscope. The measured samples have an onset critical temperature of about 4.0 K. Features often reported on similar compounds were observed in the tunnelling spectra at 1.4 K. STS spectra are compared with several models for the superconducting density of states. Our analysis evidences inhomogeneous superconductivity and indicates that the presence of a magnetic layer into the sample plays a role in determining the superconducting spectroscopic features. (C) 2008 Elsevier Masson SAS. All rights reserved.

A Molecular Metal Ferromagnet from the Organic Donor Bis(ethylenedithio)tetraselenafulvalene and Bimetallic Oxalate Complexes

2003

A new dual-function hybrid molecular material has been obtained from the organic donor bis(ethylenedithio)tetraselenafulvalene and the honeycomb oxalate-based bimetallic network [MnCr(ox)3]-. This multilayer material consists of layers of the inorganic anionic 2D network, responsible for the appearance of ferromagnetic ordering below 5.3 K, alternating with segregated layers of the organic cation radical responsible for the transport properties:  metal-like conductivity is observed from room temperature down to 150 K.

Coordination polymers based on diiron tetrakis(dithiolato) bridged by alkali metals, electrical bistability around room temperature, and strong antif…

2015

Coordination polymer chains have been formed by the direct reaction between HSC6H2Cl2SH and FeCl3·6H2O in the presence of an aqueous solution of the corresponding alkali-metal hydroxide (M = Li, Na, and K) or carbonate (M = Rb and Cs). The structures consist of dimeric [Fe2(SC6H2Cl2S)4](2-) entities bridged by [M2(THF)4] [M = K (1), Rb (2), and Cs (3); THF = tetrahydrofuran] or {[Na2(μ-H2O)2(THF)2] (5 and 5') units. The smaller size of the lithium atom yields an anion/cation ion-pair molecule, [Li(THF)4]2[Fe2(SC6H2Cl2S)4] (4), in which the dianionic moieties are held together by Cl···Cl interactions. Electrical characterization of these compounds shows a general semiconductor behavior in wh…

Coexistence of Mobile and Localized Electrons in Bis(ethylene)dithiotetrathiafulvalene(BEDT-TTF) Radical Salts with Paramagnetic Polyoxometalates: Sy…

1994

Structural, magnetic and electrical properties of one-dimensional tetraamidatodiruthenium compounds

2013

The first bromo and iodo tetraamidatodiruthenium compounds of the type [Ru2X(μ-NHOCC6H4-R)4]n [X = Br, R = o-Me (1), m-Me (2), p-Me (3); X = I, R = o-Me (4), m-Me (5), p-Me (6)] have been prepared using solvothermal or microwave activation procedures. In these reactions ethanol or methanol as solvents have been used to make the synthesis procedures more environment-friendly. Solvothermal synthesis has allowed us to isolate single crystals of these extremely insoluble compounds and the crystal structures of all of them have been determined using single crystal X-ray diffraction. The change of the bridging halide ligand permits us to discuss the properties of these complexes on the basis of t…

Hydrogen bond mediated intermolecular magnetic coupling in mononuclear high spin iron(iii) Schiff base complexes: synthesis, structure and magnetic s…

2020

The crystal structure and magnetic properties of two mononuclear iron(III) Schiff base complexes, [FeL1(NCS)2] (1), HL1 = 2-[1-[[2-[(2-aminoethyl)amino]ethyl]imino]ethyl]phenol and [FeL2(N3)Cl] (2), HL2 = 2-(-1-(2-(2-aminoethylamino)ethylimino)ethyl)-4-methylphenol are reported. Each complex contains a Fe(III) ion surrounded by a N3O Schiff base ligand and two NCS− ligands (in 1) or one N3− and one Cl− ligands (in 2). The magnetic properties can be well reproduced with zero field splittings in the high spin S = 5/2 Fe(III) ions and weak intermolecular Fe–Fe interactions mediated by hydrogen bonds. This intermolecular antiferromagnetic interaction has been validated by using DFT calculations…

Ein neuartiges Polyoxowolframat mit einemtriangulo-NiII3-Cluster mit ferromagnetischen Austauschwechselwirkungen und einemS = 3-Grundzustand

1992

Hybrid Organic/Inorganic Molecular Materials Formed by Tetrathiafulvalene Radicals and Magnetic Trimeric Clusters of Dimetallic Oxalate‐Bridged Compl…

2003

The first examples of trimeric, dimetallic, pure oxalate-bridged complexes [ox = (C2O4)2−] have been synthesized and characterized structurally and magnetically for the two new series of crystalline molecular assemblies formulated as (TTF)4{MII(H2O)2[MIII(ox)3]2}·nH2O [for MIII = Cr; MII = Mn (1), Fe (2), Co (3), Ni (4), Cu (5) and Zn (6); for MIII = Fe; MII = Mn (7), Fe (8), Co (9), Ni (10) and Zn (11)]. Both series (Cr2M and Fe2M) are isostructural. The crystal structure of (TTF)4{Mn(H2O)2[Cr(ox)3]2}⋅14H2O (1) [monoclinic, space group C2/c (no. 15), a = 13.240(5) A, b = 19.450(5) A, c = 27.690(5) A, β = 97.63(5)°, V = 7068(3) A3 and Z = 4] shows alternating layers of the organic radical T…

The key role of hydrogen bonding in the nuclearity of three copper(II) complexes with hydrazone-derived ligands and nitrogen donor heterocycles

2011

International audience; Three new Cu(II) complexes of formula [Cu(L1)(pyz)(CH3OH)]ClO4 (1), [Cu(L1)(4,4′-bpy)(ClO4)]·0.5H2O (2) and [{Cu(L2)(ClO4)}2(μ-4,4′-bpy)] (3) have been synthesised by using pyrazine (pyz) and 4,4′-bipyridine (4,4′-bpy) and tridentate O,N,O-donor hydrazone ligands, L1H and L2H, obtained by the condensation of 1,1,1-trifluoro-2,4-pentanedione with salicyloylhydrazide and benzhydrazide, respectively. The ligands and their complexes have been characterized by elemental analyses, FT-IR, and UV–Vis spectroscopies. Single crystal X-ray structure analysis evidences the metal ion in a slightly deformed square pyramidal geometry in all the complexes. However complexes 1 and 2 …

Dibenzocycloheptatriene as end-group of Thiele and tetrabenzo-Chichibabin hydrocarbons

2020

The authors are grateful for the financial support from: MICIU/FEDER/AEI, Spain (PG2018-101181-B-I00, PGC2018-095808B-I00, MAT2016-80826-R, FIP-2018-HECTIC-PTM, Prometeo2019/076 and the "Severo Ochoa" Programme for Centres of Excellence in R & D; SEV-2015-0496), the European Research Council (ERC) (677023), DGR (Catalunya) (2017-SGR-918), and SNSF (Switzerland, TS., PZ00P2_174175). We thank the CSIRC-Alhambra and SciCore (Basel, Switzerland) for supercomputing facilities and the Servei de RMN, UAB, for instrument time.

Comparative studies of oxidation processes on Group 10 Metals Dithiolene Derivatives in the formation of coordination polymers

2018

This document is the Accepted Manuscript Version of a Published Work that appeared in final form in "Crystal Growth and Design", copyright © 2018 American Chemical Society after peer review and techical editing by publisher. To access the final and published work see "Comparative Studies of Oxidation Processes on Group 10 Metals Dithiolene Derivatives in the Formation of Coordination Polymers Oscar Castillo, Esther Delgado, Carlos J. Gómez-García, Diego Hernández, Elisa Hernández, Pilar Herrasti, Avelino Martín, and Félix Zamora Crystal Growth & Design 2018 18 (4), 2486-2494

Polynitrile anions as ligands: Synthesis, structure and magnetic properties of a new three-dimensional coordination polymer with the 2-dicyanomethyle…

2005

cited By 12; International audience; Reaction between CuCl2 and K2tcpd (tcpd2- = C[C(CN)2]32- = 2-dicyanomethylenc-1,1,3,3-tetracyanopropanediide anion) in presence of the neutral ligand tn (1,3-diaminopropane) in aqueous solution yields the new compound [Cu(tn)(tcpd)] (1) which was characterized by X-ray crystallography. The crystal structure of 1 consists of one [Cu(tn)]2+ unit and one tcpd2- anion, both located on general positions. Each Cu atom presents an essentially octahedral coordination with four nitrogen atoms arising from four polynitrile ligands and two nitrogen atoms from the chelating tn ligand. Despite its six nitrile groups potentially bridging, the tcpd ligand acts with a μ…