Hybrid molecular materials formed by alternating layers of bimetallic oxalate complexes and tetrathiafulvalene molecules: Synthesis, structure, and magnetic properties of TTF4(Mn(H2O)2)[Cr(ox)3]2)·14 H2O

4,2-Ribbon like ferromagnetic cyano-bridged FeIII2NiII chains: a magneto-structural study

The low-spin iron(III) complex AsPh(4)[Fe(III)(bpy)(CN)(4)].CH(3)CN (1) [AsPh(4) = tetraphenylarsonium cation] and the heterobimetallic chains [{Fe(III)(L)(CN)(4)}(2)Ni(II)(H(2)O)(2)].4H(2)O with L = bpy (2) and phen (3) [bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline] have been prepared and their structures determined by X-ray diffraction methods. The structure of 1 consists of mononuclear [Fe(bpy)(CN)(4)](-) anions, tetraphenylarsonium cations and acetonitrile molecules of crystallization. The iron(III) is hexacoordinated with two nitrogen atoms of the bidentate bpy and four carbon atoms of four terminal cyanide groups building a distorted octahedral surrounding around the metal ato…

Synthesis, structural analysis, and magnetic properties of ethylmalonate-manganese(II) complexes

12 páginas, 10 figuras, 6 tablas.-- et al.

Solid-State Aggregation of Metallacyclophane-Based MnIICuII One-Dimensional Ladders

Two distinct one-dimensional (1) and two-dimensional (2) mixed-metal-organic polymers have been synthesized by using the "complex-as-ligand" strategy. The structure of 1 consists of isolated ladderlike Mn(II)(2)Cu(II)(2) chains separated from each other by neutral Mn(II)(2) dimers, whereas 2 possesses an overall corrugated layer structure built from additional coordinative interactions between adjacent Mn(II)(2)Cu(II)(2) ladders. Interestingly, 1 and 2 show overall ferri- and antiferromagnetic behavior, respectively, as a result of their distinct crystalline aggregation in the solid state.

Synthesis, crystal structure, and magnetic characterization of the three-dimensional compound [Co2(cbut)(H2O) 3]n (H4cbut = 1,2,3,4- cyclobutanetetracarboxylic acid)

A novel cobalt(II) complex of formula [Co2(cbut)(H 2O)3]n (1) (H4cbut = 1,2,3,4-cyclobutanetetracarboxylic acid) has been synthesized under hydrothermal conditions and its crystal structure has been determined by means of synchrotron radiation and neutron powder diffraction. The crystal structure of 1 consists of layers of cobalt(II) ions extending in the bc-plane which are pillared along the crystallographic a-axis through the skeleton of the cbut 4- ligand. Three crystallographically independent cobalt(II) ions [Co(1), Co(2), and Co(3)] occur in 1. They are all six-coordinate with four carboxylate-oxygens [Co(1)-Co(3)] and two cis-[Co(1)] or trans-water molecules [Co(2) and Co(3)] buildin…

Crystal structure and magnetic properties of the single-μ-chloro copper(II) chain [Cu(bipy)Cl2] (bipy = 2,2′-bipyridine)

Abstract The crystal and molecular structure of the copper(II) chain [Cu(bipy)Cl2] (1) (bipy = 2,2′-bipyridine) has been determined by X-ray diffraction methods. The crystal structure of 1 consists of neutral single chloro-bridged copper(II) chains with alternating short and long Cu–Cl distances through a screw axis parallel to a. The copper surrounding is best described as distorted square pyramidal, the equatorial plane being built by the two nitrogen atoms of the chelating bipy and two chlorine atoms (one terminal and the other bridging), whereas the apical position is filled by the bridging chlorine atom from the symmetry-related adjacent unit. The equatorial Cu–Cl bonds (2.291(3) and 2…

Generation of lanthanide coordination polymers with dicarboxylate ligands: synthesis, structure, thermal decomposition and magnetic properties of the two-dimensional triaquatris(malonato)dipraseodymium(III) dihydrate {[Pr2(C3H2O4)3(H2O)3]·2H2O}

The malonate complex of formula [Pr2(C3H2O4)3(H2O)3]·2H2O (1) was prepared and his crystal structure determined by X-ray diffraction methods. 1 crystallizes in the monoclinic space group P21, Z = 4, with unit cell parameters a = 7.631(2), b = 12.899(4), c = 8.923(2) A and β = 101.11(3)°. 1 is a polymer which grows in the (110) plane. The hydrogen bond stabilizes the crystal structure forming a three-dimensional network. The two non-equivalent praseodymium(III) ions have different environments. Finally, the thermal behaviour and magnetic properties were investigated.

Synthesis, crystal structure and magnetic properties of the three-dimensional compound [Na2Ni(mal)2(H2O)6]n (H2mal=malonic acid)

Abstract A new three-dimensional nickel–sodium compound of formula [Na 2 Ni(mal) 2 (H 2 O) 6 ] n (H 2 mal=malonic acid) was prepared and its structure was determined by X-ray diffraction methods. Four malonate–oxygen atoms and two trans -(Ni) or cis -(Na) coordinated water molecules build distorted octahedral surroundings around the metal atoms. The malonate group exhibits bidentate (Ni) and tetrakis-monodentate (Na) coordination modes. The structure can be described as corrugated sheets of malonato-containing Ni(II) and Na(I) cations which grow in the (101) plane, each sheet being linked to the adjacent one in the [101] direction through bis(μ-aqua)disodium(I) units. Within each corrugated…

Dinuclear, tetranuclear and one-dimensional pyrazine-based copper(II) complexes: preparation, X-ray structure and magnetic properties.

The preparation, crystal structures and magnetic properties of the copper(II) complexes of formula [Cu(2)(tppz)(H(2)O)(2)(CF(3)SO(3))(4)] (1), [Cu(tppz)(CrO(4))](n) x 3nH(2)O (2) and [Cu(4)(tppz)(4)(H(2)O)(4)(MoO(4))(2)](CF(3)SO(3))(4) x 7 H(2)O (3) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine] are reported. Complex 1 is a dinuclear species where tppz adopts a bis-tridentate bridging mode with an intramolecular copper-copper separation of 6.5221(6) A. Each copper(II) ion in 1 has an elongated octahedral geometry with three tppz nitrogen atoms and a water molecule in the equatorial positions and two triflate oxygen atoms occupying the axial sites. Complex 2 is a uniform copper(II) chain where…

Design of single chain magnets through cyanide-bearing six-coordinate complexes

Abstract The design and preparation of stable cyanide-bearing six-coordinate complexes of formula [MIII(L)(CN)x](x + l − m)− (M = trivalent transition metal ion and L = polydentate blocking ligand) are summarized here. Their use as ligands towards either fully hydrated metal ions or coordinatively unsaturated preformed species, to afford a wide variety of low-dimensional metal assemblies whose nuclearity, dimensionality and magnetic properties can be tuned, is also reviewed. Special emphasis is put on the appropriate choice of the end-cap ligand L whose denticity determines the number of coordinated cyanide groups in the mononuclear precursors. Among the different new spin topologies obtain…

New 3d–4f supramolecular systems constructed by [Fe(bipy)(CN)4]− and partially blocked lanthanide cations

Abstract The reaction of acetonitrile (1–5) and mixed acetonitrile/water 1:1 (6–9) solutions containing the cyanide-bearing [Fe(bipy)(CN)4]− building block (bipy = 2,2′-bipyridine) and the partially blocked [Ln(bpym)]3+ cation (Ln = lanthanide trivalent cation and bpym = 2,2′-bipyrimidine) has afforded two new families of 3d–4f supramolecular assemblies of formula [Ln(bpym)(NO3)2(H2O)3][Fe(bipy)(CN)4] · H2O · CH3CN [Ln = Sm (1), Gd (2), Tb (3), Dy (4) and Ho (5)] and [Ln(bpym)(NO3)2(H2O)4][Fe(bipy)(CN)4] [Ln = Pr (6), Nd (7), Sm (8), Gd (9)]. They crystallize in the P21/c (1–5) and P2/c (6–9) space groups and their structures are made up of [Fe(bipy)(CN)4]− anions (1–9) and [Ln(bpym)(NO3)2(…

Structural versatility in cobalt(ii) complexes with 1,2,4,5-benzenetetracarboxylic acid (H4bta) and 4,4′-bipyridine-N,N′-dioxide (dpo)

Four new high-spin cobalt(II) complexes of formula [Co(H2O)6](H2bta)·dpo·4H2O (1), [{Co(H2O)4(dpo)}2(bta)]·4H2O·(2), [Co(H2O)2)(dpo)2(H2bta)]n (3) and [Co(H2O)3(dpo)(bta)1/2]n (4) (H4bta = 1,2,4,5-benzenetetracarboxylic acid and dpo = 4,4′-bipyridine-N,N′-dioxide) have been synthesized and their structures solved by single crystal X-ray diffraction methods. Compound 1 is an ionic salt whose structure is made up of [Co(H2O)6]2+ cations, H2bta2− anions, uncoordinated dpo groups and crystallization water molecules, which are linked by extensive hydrogen bonds to afford a three-dimensional network. The structure of 2 consists of bta-bridged dinuclear cobalt(II) complexes where four coordinated …

A three-dimensional copper(ii) 12-metallacrown-4 complex with malonomonohydroxamic acid (H3mmh) as a ligand

Slow diffusion of an ethanolic solution of copper(ii) into an aqueous solution of partially deprotonated malonodihydroxamic acid (H4mdh) affords the pentanuclear complex of formula {[K(H2O) 2]2[Cu5(mmh)4]}n (1) (H3mmh = malonomonohydroxamic acid) which is formed by 12-MC-4 metallacrown units with the fifth copper(ii) ion being placed at the center of the square metallacrown unit. The dianionic pentacopper(ii) planar entity interacts with diaquapotassium(i) counterions through the carboxylate-oxygen atoms resulting in a neutral three-dimensional structure. Magnetic susceptibility measurements in the temperature range 1.9-300 K for 1 show the occurrence of relatively strong antiferromagnetic …

Copper(II) assembling with bis(2-pyridylcarbonyl)amidate and N,N'-2,2-phenylenebis(oxamate).

We herein present the synthesis and X-ray structures of five copper(II) complexes of formulae [Cu(bpca)(CF3SO3)(H2O)]·H2O (1), [Cu(bpca)(Phpr)(H2O)]·3/2H2O (2), {[Cu(bpca)]2[Cu(opba)(H2O)]}·H2O (3), {[Cu(bpca)]2(H2opba)}2·6H2O (4) and [Cu(bpca)(EtH2opba)]n (5), where bpca = bis(2-pyridylcarbonyl)amidate, Phpr = 3-phenylpropionate, CF3SO3(−) = triflate (anion of the trifluoromethanesulphonic acid), H4opba = N,N′-1,2-phenylenebis(oxamic acid), and EtH3opba = monoethyl ester derivative of the H4opba. 1 and 2 are mononuclear copper(II) complexes where the copper atom is five-coordinate in distorted square pyramidal surroundings with a tridentate bpca and a water molecule (1)/carboxylate oxygen …

Geometric isomeric pairs: synthesis, structure, thermal decomposition and magnetic properties of cis- and trans-[Cr(mal)(bpy)(H2O)2][NO3]·xH2O (H2mal=malonic acid, bpy=2,2′-bipyridine)

Abstract Procedures are given for the preparation and isolation of cis-[Cr(mal)(bpy)(H2O)2][NO3]·3H2O (I) and trans-[Cr(mal)(bpy)(H2O)2][NO3]·H2O (II) (H2mal=malonic acid, bpy=2,2′-bipyridine). The single crystals X-ray structure of cis-compound reveals that the cations and anions as well as cations between cations are linked into hydrogen-bonded chains. Unfortunately, little structural information is available for the trans compound II (only isotropic cation refinement), nevertheless, from this result is observed that there also exists a hydrogen-bonded network between anion units. Thermal analysis and magnetic behaviour for both compounds were studied.

New cyanide-bridged Mn(III)-M(III) heterometallic dinuclear complexes constructed from [M(III)(AA)(CN)4]- building blocks (M = Cr and Fe): synthesis, crystal structures and magnetic properties.

Three Mn(III)-M(III) (M = Cr and Fe) dinuclear complexes have been obtained by assembling [Mn(III)(SB)(H(2)O)](+) and [M(III)(AA)(CN)(4)](-) ions, where SB is the dianion of the Schiff-base resulting from the condensation of 3-methoxysalicylaldehyde with ethylenediamine (3-MeOsalen(2-)) or 1,2-cyclohexanediamine (3-MeOsalcyen(2-)): [Mn(3-MeOsalen)(H(2)O)(µ-NC)Cr(bipy)(CN)(3)]·2H(2)O (1), [Mn(3-MeOsalen)(H(2)O)(µ-NC)Cr(ampy)(CN)(3)][Mn(3-MeOsalen)(H(2)O)(2)]ClO(4)·2H(2)O (2) and [Mn(3-MeOsalcyen)(H(2)O)(µ-NC)Fe(bpym)(CN)(3)]·3H(2)O (3) (bipy = 2,2'-bipyridine, ampy = 2-aminomethylpyridine and bpym = 2,2'-bipyrimidine). The [M(AA)(CN)(4)](-) unit in 1-3 acts as a monodentate ligand towards th…

Highly selective chemical sensing in a luminescent nanoporous magnet.

Among the wide variety of properties of interest that a given material can exhibit, luminescence is attracting an increasing attention due to its potential application in optical devices for lighting equipment and optical storage, [ 1a − c] optical switching, [ 1d ,e] and sensing. [ 1f − i ] At this respect, many scientists, working in the multidisciplinary fi eld of the materials science, have directed their efforts to the obtention of luminescent materials with potential sensing applications. For instance, sensitive and selective detection of gas and vapor phase analytes can result specially interesting because of the variety of applications that can be found in many different fi elds. A …

Photoswitching of the antiferromagnetic coupling in an oxamato-based dicopper(ii) anthracenophane

Thermally reversible photomagnetic (ON/OFF) switching behavior has been observed in a dinuclear oxamatocopper(ii) anthracenophane upon UV light irradiation and heating; the two CuII ions (SCu = 1/2) that are antiferromagnetically coupled in the dicopper(ii) metallacyclic precursor (ON state) become uncoupled in the corresponding [4+4] photocycloaddition product (OFF state), as substantiated from both experimental and theoretical studies. © 2011 The Royal Society of Chemistry.

Cobalt(II) Sheet-Like Systems Based on Diacetic Ligands: from Subtle Structural Variances to Different Magnetic Behaviors

The preparation, X-ray crystallography, and magnetic investigation of the compounds [Co(H(2)O)(2)(phda)](n) (1), [Co(phda)](n) (2), and [Co(chda)](n) (3) [H(2)phda = 1,4-phenylenediacetic acid and H(2)chda = 1,1-cyclohexanediacetic acid] are described herein. The cobalt atoms in this series are six- (1) and four-coordinated (2 and 3) in distorted octahedral (CoO(6)) and tetrahedral (CoO(4)) environments. The structures of 1-3 consists of rectangular-grids which are built up by sheets of cobalt atoms linked through anti-syn carboxylate bridges, giving rise to either a three-dimensional structure across the phenyl ring (1 and 2) or to regularly stacked layers with the cyclohexyl groups acting…

1,2,4,5‐Benzenetetracarboxylic Acid and 4,4′‐Bipyridine as Ligands in Designing Low‐Dimensional Coordination Polymers

The combined use of 1,2,4,5-benzenetetracarboxylic acid (H4bta) and 4,4′-bipyridine (bpy) as ligands with MnII and CoII ions afforded two polymeric compounds with the formulae [Mn(Hbta)(Hbpy)(H2O)2] (1) and [H2bpy][Co(bta)(bpy)(H2O)2] (2). 1 and 2 were prepared under hydrothermal conditions (145 °C, 3 h) and characterized by elemental analysis, IR spectroscopy, TG-DTA analysis and single-crystal X-ray diffraction methods. 1 exhibits a novel double chain structure growing along the b axis where the manganese atoms are linked by tris-monodentate Hbta3− ligands. The values of the manganese···manganese intrachain separations are 7.627(2) A [Mn(1)···Mn(1c); c = −x + 1/2, y − 1/2, −z] and 9.274(4…

Syntheses, crystal structures and magnetic properties of five new manganese(ii) complexes: Influence of the conformation of different alkyl/aryl substituted malonate ligands on the crystal packing

et al.

Ligand effects on the dimensionality of oxamato-bridged mixed-metal open-framework magnets

Increasing dimensionality [from 2D (1) to 3D (2)] and T(C) [from 10 (1) to 20 K (2)] in two new oxamato-bridged heterobimetallic Mn(II)(2)Cu(II)(3) open-frameworks result from the steric hindrance provided by the different alkyl substituents of the N-phenyloxamate bridging ligands.

Theoretical Insights into the Ferromagnetic Coupling in Oxalato-Bridged Chromium(III)-Cobalt(II) and Chromium(III)-Manganese(II) Dinuclear Complexes with Aromatic Diimine Ligands

Two novel heterobimetallic complexes of formula [Cr(bpy)(ox)(2)Co(Me(2)phen)(H(2)O)(2)][Cr(bpy)(ox)(2)]·4H(2)O (1) and [Cr(phen)(ox)(2)Mn(phen)(H(2)O)(2)][Cr(phen)(ox)(2)]·H(2)O (2) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, and Me(2)phen = 2,9-dimethyl-1,10-phenanthroline) have been obtained through the "complex-as-ligand/complex-as-metal" strategy by using Ph(4)P[CrL(ox)(2)]·H(2)O (L = bpy and phen) and [ML'(H(2)O)(4)](NO(3))(2) (M = Co and Mn; L' = phen and Me(2)phen) as precursors. The X-ray crystal structures of 1 and 2 consist of bis(oxalato)chromate(III) mononuclear anions, [Cr(III)L(ox)(2)](-), and oxalato-bridged chromium(III)-cobalt(II) and chromium(III)-manganese(II) din…

Cyanide-bridged iron(III)-cobalt(II) double zigzag ferromagnetic chains: two new molecular magnetic nanowires.

and opened the perspective of a potential useof 1D magnetic molecular nanowires for information storage.Even though 1D magnetism is a very active area of research,such dynamic behavior was never detected before since it isnot clear how to fulfill experimentally the requirements of aperfect 1D Ising-type chain. This finding prompted us to lookcarefully at 1D systems containing anisotropic elements,suchas cobalt(ii) and low-spin iron(iii) centers that we synthesizedrecently,

Chromium(III) complexes with 2-(2′-pyridyl)imidazole: Synthesis, crystal structure and magnetic properties

Abstract The preparation, crystal structure and variable temperature-magnetic investigation of three 2-(2′-pyridyl)imidazole-containing chromium(III) complexes of formula PPh4[Cr(pyim)(C2O4)2]·H2O (1), AsPh4[Cr(pyim)(C2O4)2]·H2O (2) and [Cr2(pyim)2(C2O4)2(OH2)2]·2pyim · 6H2O (3) [pyim = 2-(2′-pyridyl)imidazole, C 2 O 4 2 - = dianion of oxalic acid , PPh 4 + = tetraphenylphosphonium cation and AsPh 4 + = tetraphenylarsonium cation ] are reported herein. The isomorphous compounds are made up of discrete [Cr(pyim)(C2O4)2]− anions, XPh 4 + cations [X = P (1) and As (2)] and uncoordinated water molecules. The chromium environment in 1 and 2 is distorted octahedral with Cr–N and Cr–O bond distanc…

Unprecedented coexistence of cyano-bridged Mn4(III)Cr(III) and Mn2(III)Cr(III) heterobimetallic complexes in one single crystal.

The penta-[{MnIII(4-MeO-salen)(H2O)(micro-CN)}4CrIII(CN)2]+ and trinuclear [{MnIII(4-MeO-salen)(H2O)(micro-CN)}2CrIII(CN)4](-) units coexist in 1 with weak antiferromagnetic interactions which are overcome by a dc magnetic field of 2.5 T.

Molecular Engineering To Control the Magnetic Interaction between Single-Chain Magnets Assembled in a Two-Dimensional Network

International audience; Two two-dimensional (2D) systems having the formula [{Fe-III(dmbpy)(CN)(4)}(2)(CoL)-L-II](n) [L = pyetNO (1), tvpNO (2)] and consisting of single-chain magnets connected through organic ligands (L) have been prepared, and their magnetic properties have been investigated. The overall magnetic behavior depends on the capacity of the organic pillars to transmit long-range magnetic interactions. 1 is the first example of a 2D compound exhibiting double relaxation of the magnetization, whereas 2 behaves as a metamagnet.

Selective Gas and Vapor Sorption and Magnetic Sensing by an Isoreticular Mixed-Metal–Organic Framework

A novel isoreticular oxamato-based manganese(II)-copper(II) open metal-organic framework H(2)O@iso1 featuring a pillared square/octagonal layer structure with alternating open and closed octagonal pores has been rationally prepared. The open-framework topology is responsible for a large selectivity in the separation of small gas (CO(2) over CH(4)) and vapor molecules (CH(3)OH over CH(3)CN and CH(3)CH(2)OH). H(2)O@iso1 displays a long-range three-dimensional ferromagnetic ordering with a drastic variation of the critical temperature as a function of the guest molecule [T(C)2.0 K (CO(2)@iso1 and CH(4)@iso1) and T(C) = 6.5 (CH(3)OH@iso1) and 21.0 K (H(2)O@iso1)].

Redox switching of the antiferromagnetic coupling in permethylated dicopper(ii) paracyclophanes

A unique magnetic electroswitching behavior has been observed in an oxamato-based permethylated dicopper(II) paracyclophane; upon reversible one-electron oxidation of the double tetramethyl-substituted p-phenylenediamidate bridging skeleton, the spin alignment of the two Cu(II) ions (S(Cu) = ½) changes from antiparallel (OFF) to parallel (ON) in the resulting dicopper(II) π-radical cation species.

Crystal structure and magnetic properties of the flexible self-assembled two-dimensional square network complex [Cu2(mal)2(H2O)2(4,4′-bpy)] (H2mal=malonic acid and 4,4′-bpy=4,4′-bipyridine)

Abstract The copper(II) complex [Cu 2 (mal) 2 (H 2 O) 2 (4,4′-bpy)] ( 1 ) (H 2 mal=malonic acid and 4,4′-bpy=4,4′-bipyridine) has been prepared and its structure determined by single crystal X-diffraction methods. Compound 1 has a two-dimensional square grid network structure. The square grids are stacked parallel but in a staggered manner on each other along the c -axis, with an interlayer separation of 3.850(1) A. Each layer contains a large cavity of 15.784(1)×15.784(1) A with each edge shared by one malonate group and one 4,4′-bpy ligand and a small planar square of 4.644(1)×4.644(1) A with Cu(II) ions and malonate groups at each corner and side, respectively. Each copper atom is in a d…

Synthesis and crystal structure of the low-spin iron(II) complex [Fe(bpz)3](ClO4)2·H2O (bpz=2,2′-bipyrazine)

Abstract The crystal structure of the title compound [Fe(bpz) 3 ](ClO 4 ) 2  · H 2 O (bpz=2,2 ′ -bipyrazine) has been determined by a single crystal X-ray diffraction study at 293(2) K. The complex is monoclinic, P 2 1 / c , a =17.263(3), b =9.983(2), c =17.921(4) A, β =107.94(3)°, V =2938.3(10) A 3 , Z =4, R =0.073 and R w =0.118. The structure is made up of tris-chelated [Fe(bpz) 3 ] 2+ cations, uncoordinated perchlorate anions and crystallization water molecules. The iron atom exhibits a FeN 6 distorted octahedral geometry with average Fe–N bond length and N–Fe–N bidentate angle of 1.962(5) A and 81.6(2)°. The value of the Fe–N bond distance and that of the room temperature magnetic mome…

Dicopper(II) metallacyclophanes with photoswitchable oligoacene spacers: a joint experimental and computational study on molecular magnetic photoswitches

Dinuclear copper(II) complexes of the metallacyclophane-type, (nBu4N)4[Cu2(2,6-anba)2] (1) and (nBu4N)4[Cu2(1,5-naba)2]·4H2O (2) with photoactive 2,6-anthracene-(2,6-anba) and 1,5-naphthalenebis(oxamate) (1,5-naba) bridging ligands, are reported. They undergo a thermally reversible, solid-state photomagnetic (ON/OFF) switching between the moderately strong antiferromagnetically coupled dicopper(II) species and the corresponding magnetically uncoupled [4+4] photocycloaddition product. Density functional calculations give further insights on the intramolecular (“pseudo-bimolecular”) photocycloaddition reaction of the two facing 2,6-anthracene or 1,5-naphthalene spacers in this novel family of…

Synthesis, crystal structure and magnetic characterization of a series of CuII-LnIII heterometallic [Ln = La, Ce, Pr, Nd and Sm) metal-organic compounds with an unusual single crystal to single crystal phase transition

The synthesis and structural characterization of five Cu(II)-Ln(III) heteronuclear metal-organic frameworks of formula {[Ln4Cu 4(H2O)26(bta)5]·mH 2O}n and {[Ln4Cu4(H 2O)24(bta)5]·pH2O} n [Ln = LaIII (1A/1B), CeIII (2A/2B), Pr III (3A/3B), NdIII (4A/4B) and SmIII (5A/5B) with m/p = 20 (1A)/16 (1B), 18 (2A)/16 (2B), 14 (3A)/16 (3B), 22 (4A)/16 (4B) and 21 (5A)/14 (5B); H4bta =1,2,4,5-benzenetetracarboxylic acid (1-5)] have been performed. These compounds present a single-crystal to single-crystal phase transition from expanded A phases toward the B shrinking networks, which is triggered only in the presence of a dry environment. This phase transition is accompanied by a compression of the cry…

Synthesis, crystal structure and magnetic properties of [Cu(bpym)(mal)(H2O)]·6H2O and [Cu2(bpym)(mal)2(H2O)2]·4H2O (bpym=2,2′-bipyrimidine, H2mal=malonic acid)

Abstract Two new mixed-ligand complexes of formula [Cu(bpym)(mal)(H2O)]·6H2O (1) and [Cu2(bpym)(mal)2(H2O)2]·4H2O (2) (bpym=2,2′-bipyrimidine and H2mal=malonic acid) have been synthesised and characterised by X-ray diffraction methods. The crystal structure of 1 consists of mononuclear [Cu(bpym)(mal)(H2O)] units in which the copper atom shows a slightly distorted square-pyramidal environment with two bpym-nitrogen and two malonate-oxygen atoms forming the equatorial plane and a water molecule in the axial position. The structure of 2 is built by centrosymmetric bpym-bridged dinuclear [Cu2(bpym)(mal)2(H2O)2] units, in which the geometry of each Cu(II) ion is similar to that found in 1. Malon…

Solid-state dinuclear-to-trinuclear conversion in an oxalato-bridged chromium(III)-cobalt(II) complex as a new route toward single-molecule magnets.

A novel bis(oxalato)chromium(III) salt of a ferromagnetically coupled, oxalato-bridged dinuclear chromium(III)-cobalt(II) complex of formula [CrL(ox)(2)CoL'(H(2)O)(2)][CrL(ox)(2)]·4H(2)O (1) has been self-assembled in solution using different aromatic α,α'-diimines as blocking ligands, such as 2,2'-bipyridine (L = bpy) and 2,9-dimethyl-1,10-phenanthroline (L' = Me(2)phen). Thermal dehydration of 1 leads to an intriguing solid-state reaction between the S = 3/2 Cr(III) anions and the S = 3 Cr(III)Co(II) cations to give a ferromagnetically coupled, oxalato-bridged trinuclear chromium(III)-cobalt(II) complex of formula {[CrL(ox)(2)](2)CoL'} (2). Complex 2 possesses a moderately anisotropic S =…

[MIII(bpym)(CN)4]−: a suitable building block to design ferrimagnetic cyano-bridged heterobimetallic chains (M = Fe, Cr; bpym = 2,2′-bypyrimidine)

Two cyano-bridged M(III)Mn(III) [M = Fe () and Cr ()] ferrimagnetic chains are reported; exhibits metamagnetism with two critical fields of 1250 G and 2.0 T which correspond to the overcoming by the applied dc field of the inter- and intrachain magnetic interactions, respectively.

Influence of the coligand in the magnetic properties of a series of copper(ii)–phenylmalonate complexes

This work presents a series of layered systems based on phenylmalonate-containing copper(II) complexes and different coligands. Eight compounds [Cu(L)(Phmal)]n where L = pyrimidine (pym, 1) pyrazine (pyz, 2), 3-cyanopyridine (3-CNpy, 3), 4-cyanopyridine (4-CNpy, 4), 3-fluoropyridine (3-Fpy, 5), 3-chloropyridine (3-Clpy, 6), 3-bromopyridine (3-Brpy, 7) and 3-iodopyridine (3-Ipy, 8), have been synthesized and magneto-structurally characterized. The coligands selected not only modify the coordination environment of the metal ion, blocking or extending the polymerization, but also interact with the phenyl ring of the phenylmalonate ligand and dramatically affect the crystal packing through weak…

Tuning the Spin Ground State in Heterononanuclear Nickel(II)−Copper(II) Cylinders with a Triangular Metallacyclophane Core

3 páginas, 2 figuras, 1 gráfico.-- et al.

Metallosupramolecular approach toward multifunctional magnetic devices for molecular spintronics

Abstract The work presented in this review constitutes a successful extension of our group's research on the chemistry and physics of dinuclear copper(II) metallacyclophanes with aromatic polyoxalamide ligands. The design and synthesis of metallacyclic complexes that contain multiple electro- and photoactive (either metal- or ligand-based) spin carriers and the study of their spectroscopic and magnetic properties as well as their redox and photochemical activity are of large interest in the multidisciplinary field of metallosupramolecular chemistry. In doing this, a ligand design approach has been followed which is based on the copper(II)-mediated self-assembly of bis(oxamato) bridging liga…

Low-dimensional copper(II) complexes with the trinucleating ligand 2,4,6-tris(di-2-pyridylamine)-1,3,5-triazine: synthesis, crystal structures, and magnetic properties.

The preparation and structural characterization of three new copper(II) complexes of formula [Cu(3)(dipyatriz)(2)(H(2)O)(3)](ClO(4))(6) x 2 H(2)O (1), {[Cu(4)(dipyatriz)(2)(H(2)O)(2)(NO(3))(2)(ox)(2)](NO(3))(2) x 2 H(2)O}(n) (2), and [Cu(6)(dipyatriz)(2)(H(2)O)(9)(NO(3))(3)(ox)(3)](NO(3))(3) x 4 H(2)O (3) [dipyatriz = 2,4,6-tris(di-2-pyridylamine)-1,3,5-triazine and ox = oxalate] are reported. The structure of 1 consists of trinuclear units [Cu(3)(dipyatriz)(2)(H(2)O)(3)](6+) and uncoordinated perchlorate anions. The two dipyatriz molecules in 1 act as tris-bidentate ligands with the triazine cores being in a quasi eclipsed conformation. Each copper atom in 1 exhibits a distorted square pyr…

Synthesis, structural analysis, and thermal and spectroscopic studies of methylmalonate-containing zinc(II) complexes

The synthesis, crystal structure, thermal analysis and spectroscopic studies of five zinc(II) complexes of formulae [Zn(Memal)(H2O)]n (1) and [Zn2(L)(Memal)2(H2O)2]n (2-5) [H2Memal = methylmalonic acid, and L = 4,4′-bipyridine (4,4′-bpy) (2), 1,2-bis(4-pyridyl)ethylene (bpe) (3), 1,2-bis(4-pyridyl)ethane (bpa) (4) and 4,4′-azobispyridine (azpy) (5)] are presented here. The crystal structure of 1 is a three-dimensional arrangement of zinc(II) cations interconnected by methylmalonate groups adopting the μ3-κ2O:κO’:κO”:κO”’ coordination mode to afford a rare (10,3)-d utp-network. The structures of the compounds 2-5 are also three-dimensional and they consist of corrugated square layers of meth…

Crystal structure analysis of supramolecular arrangements in bis(1-isoquinolinecarboxamide)alkanes and their Ag(i) complexes

A homologous series of bis(1-isoquinolinecarboxamide)alkane derivatives (3a–f) with two to seven carbon atoms in the alkyl bridge and their Ag(I) complexes (4a–f) have been synthesized. Four ligand and five Ag(I) complex crystal structures were obtained by single crystal X-ray diffraction and analyzed in terms of: a) their structural patterns based on intra- and intermolecular hydrogen bonds which were compared to those of bis(2-quinolinecarboxamide)alkanes (1n) and bis(6-quinolinecarboxamide)alkanes (2n) attending to specific geometrical parameters and b) the Ag(I) coordinate bond effect on these patterns and the amide-to-amide hydrogen bonds. The crystal structures of the ligands 3a, 3c, …

Versatile supramolecular self-assembly : Part II. Network formation and magnetic behaviour of copper(ii) malonate anions in ammonium derivatives

Five new metal–organic compounds of formula An[Cu(mal)2(H2O)m] (A being an amine cation and H2mal = malonic acid) have been structurally and magnetically characterized. The crystal structure of these compounds consists of an alternation of malonate-containing copper(II) anionic and amine cationic layers. Depending on the amine cation, the bis(malonate)cuprate(II) units can be connected to other units through carboxylate bridges resulting in anionic networks which exhibit different topologies: monomers (2 and 5), layers (3 and 4) and three-dimensional structures (1). Hydrogen bonding plays an important role in the self-assembling of metal–organic compounds and how the size of the amine catio…

The flexibility of molecular components as a suitable tool in designing extended magnetic systems

In this work we show how the design of n-dimensional magnetic compounds (nD with n = 1–3) can strongly benefit from the use crystal engineering techniques, which can give rive to structures of different shapes with different properties. We focus on the networks built by assembling the malonato-bridged tetranuclear copper(II) units Cu4(mal)4 (mal2− is the dianion of propanedioic acid, H2mal) through the potentially bridging 2,4′-bipyridine (2,4′-bpy), 4,4′-bipyridine (4,4′-bpy) and pyrazine (pyz). The magneto-structural study of the complexes of formula [Cu4(mal)4(2,4′-bpy)4(H2O)4]·8H2O (1), [Cu4(mal)4(H2O)4(4,4′-bpy)2] (2) (this compound was the subject of a previous report but it is includ…

Versatile supramolecular self-assembly. Part I. Network formation and magnetic behaviour of the alkaline salts of the bis(malonate)cuprate(ii) anion

Five malonate-containing copper(II) compounds of formula {[A(H2O)n]2 [Cu(mal)2(H2O)m]} [A = Li (1), Na (2), K (3), Rb (4) and Cs (5); H2mal = malonic acid] have been synthetized and characterized by X-ray diffraction. The structure of these compounds consists of bis(malonate)cuprate(II) anions and alkaline cations that are held together by means of carboxylate bridges and water molecules leading to 3D networks. A study of the self-assembling of the bis(malonate)cuprate(II) and the alkaline cations is carried out, the size of the alkaline metal ion playing an important role in the control of the resulting malonate-bridged copper(II) structure. A regular alternation of layers of anionic malon…

Novel cobalt(II) coordination polymers based on 1,2,4,5-benzenetetracarboxylic acid and extended bis-monodentate ligands

Four new high-spin cobalt(II) complexes of formulae [Co2(bta)(4,4′-bpy)2(H2O)2]n (1), {Hbpe[Co(Hbta)(bpe)(H2O)2]}n (2), {[Co(H2bta)(azpy)(H2O)2]·azpy}n (3) and {[Co2(bta)(bpa)2(H2O)4]·8H2O}n (4) with H4bta = 1,2,4,5-benzenetetracarboxylic acid, 4,4′-bpy = 4,4′-bipyridine, bpe = trans-1,2-bis(4-pyridyl)ethene, azpy = 4,4′-azobispyridine and bpa = trans-1,2-bis(4-pyridyl)ethane, have been prepared and characterized by single crystal X-ray diffraction. Compounds 1–4 exhibit two-dimensional networks where the fully (1 and 4) or partially (2 and 3) deprotonated tetracarboxylic ligand connects two (2 and 3) or four (1 and 4) cobalt(II) ions through two trans-carboxylate (1–3) or all the carboxyla…

Magnetic coupling in discrete cyano-bridged Mn(III)-Fe(III) motifs: synthesis, crystal structure, magnetic properties and theoretical study.

The preparation, crystal structures and magnetic properties of the heterobimetallic complexes of formula [Mn(III)(n-MeOsalen)(H(2)O)(mu-CN)Fe(III)(bpym)(CN)(3)]·mH(2)O with n = m = 3 (1) and n = 4 and m = 2 (2) [n-MeOsalen(2-) = N,N'-ethylenebis(n-methoxysalicylideneiminate) dianion and bpym = 2,2'-bipyrimidine] are reported. 1 and 2 are dinuclear neutral species where the cyano-bearing low-spin unit [Fe(III)(bpym)(CN)(4)](-) acts as a monodentate ligand towards the [Mn(III)(SB)(solv)(x)](+) entity (SB = tetradentate Schiff-base) through one of its four cyano groups. Adjacent heterobimetallic units are interlinked through hydrogen bonds involving the coordinated water molecule of one dinucl…

Photoluminescent and Slow Magnetic Relaxation Studies on Lanthanide(III)-2,5-pyrazinedicarboxylate Frameworks

In the series described in this work, the hydrothermal synthesis led to oxidation of the 5-methyl-pyrazinecarboxylate anion to the 2,5-pyrazinedicarboxylate dianion (2,5-pzdc) allowing the preparation of three-dimensional (3D) lanthanide(III) organic frameworks of formula {[Ln2(2,5-pzdc)3(H2O)4]·6H2O}n [Ln = Ce (1), Pr (2), Nd (3), and Eu (4)] and {[Er2(2,5-pzdc)3(H2O)4]·5H2O}n (5). Single-crystal X-ray diffraction on 1–5 reveals that they crystallize in the triclinic system, P1 space group with the series 1–4 being isostructural. The crystal structure of the five compounds are 3D with the lanthanide(III) ions linked through 2,5-pzdc2– dianions acting as two- and fourfold connectors, buildi…

Synthesis, crystal structure and magnetic properties of the malonato-bridged bimetallic chain [Mn(II)Cu(II)(mal)2(H2O)4]·2H2O

Abstract The first malonato-bridged bimetallic chain of formula [MnCu(mal)2(H2O)4]·2H2O (1) (H2mal=malonic acid) was prepared and its structure determined by X-ray diffraction methods. Each copper atom in 1 is in a square planar environment formed by four malonate-oxygens from two malonate ligands. The manganese atom is six-coordinated with four water molecules and two cis-coordinated malonate-oxygens from two malonate groups building a distorted octahedral surrounding. The malonate group acts simultaneously as bidentate and monodentate ligand towards copper and manganese atoms respectively, leading to a bimetallic chain. Two structurally different carboxylato-bridges exhibiting an anti–syn…

A new eight-coordinate complex of manganese(II): synthesis, crystal structure, spectroscopy and magnetic properties of [Mn(Hoxam)2(H2O)4] (H2oxam=oxamic acid)

Abstract The crystal structure of an eight-coordinate manganese(II) compound containing oxamato and water molecules as ligands [Mn(Hoxam)2(H2O)4], were H2oxam=oxamic acid, has been determined by X-ray diffraction on single-crystals. The coordinated oxygen atoms are located at the vertices (corners) of a distorted bicapped trigonal antiprism. Hydrogen bonding is responsible for an extended 3D-network. The magnetic susceptibility data of the compound have been investigated. χMT follows the Curie law, at very low temperatures χMT decreases smoothly due to weak intermolecular interactions and/or due to a small zero field splitting of the sextuplet spin state of the Mn(II).

Cadmium(ii) coordination polymers based on substituted malonic acid: synthesis, characterization and photoluminescence properties

Four novel complexes of cadmium(II) with alkyl/aryl-substituted malonate ligands of formulae {[Cd(Memal)(H2O)]6·0.5H2O}n (1), [Cd(Etmal)(H2O)]n (2), [Cd(Butmal)(H2O)]n (3) and [Cd(Bzmal)(H2O)]n (4), (Memal = methylmalonate, Etmal = ethylmalonate, Butmal = butylmalonate and Bzmal = benzylmalonate) have been prepared and characterized by single crystal X-ray analysis. Their luminescence, UV-Vis absorption properties and thermal behaviour were also investigated. Complex 1 is a three-dimensional compound where each metal centre is connected to four other ones leading to a sodalite network with the point symbol {42·64}. Each cadmium(II) ion in 1 is seven-coordinate with a water molecule and six …

Structural versatility of the malonate ligand as a tool for crystal engineering in the design of molecular magnets

The synthesis of ferro- and ferri-magnetic systems with a tunable Tc and three-dimensional (3-D) ordering from molecular precursors implying transition metal ions is one of the active branches of molecular inorganic chemistry. The nature of the interactions between the transition metal ions (or transition metal ions and radicals) is not so easy to grasp by synthetic chemists working in this field since it may be either electrostatic (orbital) or magnetic (mainly dipolar). Therefore, the systems fulfilling the necessary requirements to present the expected magnetic properties are not so easy to design on paper and realize in the beaker. In this work we show how the design of one-, two- and t…

Hybrid Organic/Inorganic Molecular Materials Formed by Tetrathiafulvalene Radicals and Magnetic Trimeric Clusters of Dimetallic Oxalate‐Bridged Complexes: The Series (TTF) 4 {M II (H 2 O) 2 [M III (ox) 3 ] 2 }· n H 2 O (M II = Mn, Fe, Co, Ni, Cu and Zn; M III = Cr and Fe; ox = C 2 O 4 2− )

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…

New anionic cobalt complexes using highly hindered bis-amides with varying donor abilities as ligands.

Four potential tetradentate ligands of formulae 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)ethane (H(4)L(1), 1), 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)propane (H(4)L(2), 2), 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)benzene (H(4)L(3), 3) and 1,8-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)naphthalene (H(4)L(4), 4) have been prepared and the crystal structures of three of them (1, 3 and 4) determined by single crystal X-ray diffraction. The investigation of their complexing ability toward Co(II) afforded the compounds of formulae [Co(III)(L(3))Na(I)(H(2)O)(2)] (5), [Co(III)(L(n))Li(I)(H(2)O)2] with n = 1 (6), 2 (7) and 3 (8) and [Co(II)(L(4))Li(I)(2)] (9). Complexes 5-8 are squa…

Long-distance magnetic coupling in dinuclear copper(II) complexes with oligo-para-phenylenediamine bridging ligands

Abstract Two novel dinuclear copper(II) complexes of formulae [Cu2(tren)2(bpda)](ClO4)4 (2) and [Cu2(tren)2(tpda)](ClO4)4 (3) containing the tripodal tris(2-aminoethyl)amine (tren) terminal ligand and the 4,4′-biphenylenediamine (bpda) and 4,4″-p-terphenylenediamine (tpda) bridging ligands have been synthesized and structurally, spectroscopically, and magnetically characterized. Their experimentally available electronic spectroscopic and magnetic properties have been reasonably reproduced by DFT and TDDFT calculations. Single crystal X-ray diffraction analysis of 2 shows the presence of dicopper(II) cations where the bpda bridging ligand adopts a bismonodentate coordination mode toward two …

Two-Dimensional 3d–4f Heterometallic Coordination Polymers: Syntheses, Crystal Structures, and Magnetic Properties of Six New Co(II)–Ln(III) Compounds

Six new heterometallic cobalt(II)-lanthanide(III) complexes of formulas [Ln(bta)(H2O)2]2[Co(H2O) 6]·10H2O [Ln = Nd(III) (1) and Eu(III) (2)] and [Ln2Co(bta)2(H2O)8] n·6nH2O [Ln = Eu(III) (3), Sm(III) (4), Gd(III) (5), and Tb(III) (6)] (H4bta = 1,2,4,5-benzenetretracaboxylic acid) have been synthesized and characterized via single-crystal X-ray diffraction. 1 and 2 are isostructural compounds with a structure composed of anionic layers of [Ln(bta)(H2O)2]n n- sandwiching mononuclear [Co(H2O)6]2+ cations plus crystallization water molecules, which are interlinked by electrostatic forces and hydrogen bonds, leading to a supramolecular three-dimensional network. 3-6 are also isostructural compou…

Crystal structures and magnetic properties of two- and three-dimensional malonato-bridged manganese(ii) complexes

Two new manganese(II) compounds of formula [Mn(mal)(H2O)(2,4′-bpy)]n (1) and [Mn2(mal)2(H2O)2(4,4′-bpy)]n (2) (2,4′-bpy = 2,4′-bipyridine, 4,4′-bpy = 4,4′-bipyridine and H2mal = malonic acid) have been prepared and structurally characterized by X-ray crystallography. Their structures are made up of two- (1) and three-dimensional (2) arrangements of manganese atoms linked by carboxylate-malonate groups in the anti–syn bridging mode (1 and 2) and bis(monodentate) 4,4′-bpy (2). The 2,4′-bpy group in 1 acts as a monodentate ligand. Each manganese atom in 1 and 2 is six-coordinated with four carboxylate-oxygens in the equatorial plane and a nitrogen atom and a water molecule in the axial positio…

Synthesis, crystal structure and magnetic properties of a new cyanide-bridged mixed-valence copper(I)/copper(II) clathrate

A unique cyanide-bridge mixed-valence CuI/CuII clathrate of formula [CuI2(CN)3][{CuII(tren)}2(μ-CN)](CF3SO3)2 [tren = tris(2-aminoethyl)amine] containing cyanide-bridged [{CuII(tren)}2(μ-CN)]3 + binuclear cations stacked between anionic honeycomb layered copper(I) cyanide networks, was synthesized and structurally characterized by single crystal X-ray diffraction. Variable-temperature magnetic susceptibility studies showed that the cyanide bridge mediates a strong antiferromagnetic interaction between the copper(II) centers (J = − 160 cm− 1, the spin Hamiltonian being defined as H = − JSA⋅SB).

Influence of the alkaline earth cations on the topology of MII/CuII mixed-metal-organic frameworks (M = Ca, Sr and Ba)

The use of the mononuclear copper(ii) complex, [Cu II(Me 2pma) 2] 2- (Me 2pma = N-2,6-dimethylphenyloxamate), as a bis(bidentate) metalloligand toward solvated alkaline earth metal cations affords a new series of oxamato-bridged heterobimetallic two-dimensional compounds with mixed square-octagonal [Ca II 2Cu II 3] or square [M II 2Cu II 3] (M = Sr and Ba) layered structures of (4·82) and (44·62) net topologies, respectively. © 2012 The Royal Society of Chemistry.

Self-assembly and magnetic properties of a double-propeller octanuclear copper(II) complex with a meso-helicate-type metallacryptand core.

An octanuclear copper(II) complex possessing a dimer-of-tetramers structure self-assembles from a binuclear oxamatocopper(II) metallacryptand of the meso-helicate type; its magnetic behaviour is consistent with its unique double-propeller molecular topology. Pardo Marín, Emilio José, Emilio.Pardo@uv.es ; Julve Olcina, Miguel, Miguel.Julve@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es ; Ruiz Garcia, Rafael, Rafael.Ruiz@uv.es

Synthesis, crystal structure and magnetic properties of two-dimensional malonato-bridged cobalt(ii) and nickel(ii) compounds

Two isostructural malonato-bridged complexes of formula {[M(H2O)2][M(mal)2(H2O)2]}n [M = Co(II) (1), Ni(II) (2); H2mal = malonic acid] have been synthesised and characterized by X-ray diffraction. Their structure consists of corrugated layers of trans-diaquabismalonatemetalate(II) and trans-diaquametal(II) units bridged by carboxylate–malonate groups in the anti–syn conformation. Two crystallographycally independent metal atoms occur in 1 and 2. The malonate anion acts simultaneously as a bidentate and bis-monodentate ligand. Variable-temperature (1.9–295 K) magnetic susceptibility measurements indicate the occurrence of weak antiferro- (1) and ferromagnetic (2) interactions between the cob…

The construction of open GdIII metal–organic frameworks based on methanetriacetic acid: New objects with an old ligand

11 páginas, 11 figuras, 2 esquemas.-- et al.