Search results for "CRYSTALLOGRAPHY"

Photomagnetic properties of an Fe(ii) spin-crossover complex of 6-(3,5-diamino-2,4,6-triazinyl)-2,2'-bipyridine and its insertion into 2D and 3D bime…

2017

International audience; The Fe(ii) complex of the L1 ligand (L1 = 6-(3,5-diamino-2,4,6-triazinyl)-2,2'-bipyridine) has been used as a templating cation for the growth of oxalate-based networks. The magnetic characterization of the [Fe(II)(L1)2](ClO4)2·CH3CN (1) precursor in the solid state has been performed for the first time showing that the low-spin (LS) state is predominating from 2 to 400 K with 10% of Fe(ii), which undergoes a gradual and irreversible spin-crossover above 350 K. 1 presents the LIESST effect with a photo-conversion close to 25% and a T(LIESST) of 49 K. During the preparation of 1, a secondary product of the formula [Fe(II)(L1)(CH3CN)2(H2O)](ClO4)2·CH3CN (2) has been ob…

Recent studies on RR′S·C2B9H11 charge-compensated ligands

2002

Abstract In this paper we report the synthesis of three new carborane derivatives of the series 7,8-R,R′-10-L-7,8-C2B9H9 (R=R′=H, L=SEtPh; R=CH3, R′=H, L=SMe2 and L=SEt2) along with the enhanced characterization of formerly described compounds 7,8-R,R′-10-L-7,8-C2B9H9 (R=R′=H, L=SMe2 (1), L=SEt2 (2) and L=S(CH2)4 (3)). They have been fully characterised using 1H-, 11B- and 13C-NMR spectroscopy. Their bridging proton resonances have been located for the first time. Individual sulfonium substituent contributions have been calculated that have permitted to establish a rule to predict its position in the 1H-NMR spectrum. The crystal structures of 1 and 3 have been resolved for the first time. T…

Solvent effects on the dimensionality of oxamato-bridged manganese(II) compounds

2018

Two new oxamate-containing manganese(II) complexes, [{Mn(H2edpba)(H2O)2}2]n (1) and [Mn(H2edpba)(dmso)2]∙dmso∙CH3COCH3∙H2O (2) (H4edpba = N,N′-ethylenediphenylenebis(oxamic acid) and dmso = dimethylsulfoxide), have been synthesized and the structures of 1 and 2 were characterized by single crystal X-ray diffraction. The structure of 1 consists of neutral honeycomb networks in which each manganese(II) is six-coordinate by one H2edpba2− ligand and two carboxylate–oxygens from two other H2edpba2− ligands building the equatorial plane. Each manganese is connected to its nearest neighbor through two carboxylate(monoprotonated oxamate) bridges in an anti-syn conformation. A dmso solution of singl…

Self‐Assembly and Characterisation of Grid‐Type Iron( II ), Cobalt( II ) and Zinc( II ) Complexes

2003

The reaction of the ligands 5 and 6, containing two tridentate binding units, with iron(II), cobalt(II) and zinc(II) leads to the self-assembly of supramolecular architectures of [2 × 2] grid type containing four ions in octahedral coordination sites. The grid-type structures have been assigned on the basis of the spectroscopic data in solution, and confirmed in the solid state in the case of complexes 6b and 6c by X-ray crystallography. The latter study revealed that each metal ion is situated in a distorted octahedral coordination environment comprising two N,N,O ligand donor sets. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

On the magneto-structural role of the coordinating anion in oxamato-bridged copper(ii) derivatives

2019

We herein present the synthesis, spectroscopic analysis, description of the crystal structures and magnetic properties of four new complexes of the formula [{Cu(opba)(H2O)1.2}{Cu(dmphen)(SCN)}2]·dmf (1), [{Cu(opba)}2{Cu(dmphen)Cl}4]·1.5dmf·2.5dmso (2), [{Cu(opba)}2{Cu(dmphen)Br}4]·dmf·2.3dmso (3) and [{Cu(opba)}{Cu(dmphen)(dca)}2]n (4) [H4opba = N,N′-1,2-phenylenebis(oxamic acid), dmphen = 2,9-dimethyl-1,10-phenanthroline and dca = dicyanamide anion]. 1 is a neutral tricopper(II) complex where an inner [Cu(opba)]2− fragment adopts a bis-bidentate coordination mode towards two outer [Cu(dmphen)(NCS)]+ units. 2 and 3 are bis-trinuclear species where two oxamato-bridged [Cu(opba){Cu(dmphen)X}2…

Effects of Remote Ligand Substituents on the Structures, Spectroscopic, and Magnetic Properties of Two-Coordinate Transition-Metal Thiolate Complexes

2018

The first-row transition-metal(II) dithiolates M(SAriPr4)2 [AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2; M = Cr (1), Mn (3), Fe (4), Co (5), Ni (6), and Zn (7)] and Cr(SArMe6)2 [2; ArMe6 = C6H3-2,6-(C6H2-2,4,6-Me3)2] and the ligand-transfer reagent (NaSAriPr4)2 (8) are described. In contrast to their M(SAriPr6)2 (M = Cr, Mn, Fe, Co, Ni, and Zn; AriPr6 = C6H3-2,6-(C6H2-2,4,6-iPr3)2) congeners, which differ from 1 and 3-6 in having p-isopropyl groups on the flanking aryl rings of the terphenyl substituents, compounds 1 and 4-6 display highly bent coordination geometries with S-M-S angles of 109.802(2)° (1), 120.2828(3)° (4), 91.730(3)° (5), and 92.68(2)° (6) as well as relatively close metal-flanking …

A carboxylate-bridged NiII8 cluster with a distorted cubane topology: structure, magnetism and density functional studies

2016

Using a dicarboxylate ligand appended with (2-pyridyl)ethylamine unit, a new cluster [NiII8(L4)6(DMF)2(CH3OH)2(H2O)6][ClO4]4·2CH3OH·2CH3CO2C2H5 (1) [L4(2−): 3-[N-{2-(pyridin-2-yl)ethyl}amino]-bis(propionate)] has been synthesized, through ‘coordination-driven self-assembly’. The crystal structure of 1 reveals a centrosymmetric octanuclear carboxylate-bridged nickel(II) tetracation, with a distorted cubane topology. The four crystallographically independent nickel(II) centres differ markedly in their coordination environment. Magnetic studies (2–300 K) reveal that in 1 the net magnetic-exchange is antiferromagnetic. Based on geometric parameters associated with two interacting nickel(II) cen…

CuII2, CuII4 and CuII6 complexes with 3-(2-pyridyl)pyrazolate. Structure, magnetism and core interconversion

2019

Abstract Reactions of stoichiometric amounts of L1(−) (HL1 = 3-(2-pyridyl)pyrazole) with [Cu(H2O)6](ClO4)2, with or without PhCO2−, in MeOH or N,N′-dimethylformamide (dmf), led to the isolation of three copper(II) complexes of varying nuclearity, [CuII2(L1)2(ClO4)2(MeOH)2] (1), [CuII4(L1)4(O2CPh)2(MeOH)4](ClO4)2·2H2O (2) and [CuII6(L1)6(O2CPh)2(ClO4)2(dmf)4](ClO4)2·2dmf·2H2O (3). Structural analysis reveals two centrosymmetric four-coordinate {CuII(L1)(ClO4)(MeOH)} units are dipyrazolate-bridged in 1, giving rise to a square-pyramidal (SP; τ = 0.13) coordination to the CuII ion. In 2, two centrosymmetric four-coordinate dipyrazolate-bridged {CuII2(μ-L1)2(MeOH)2}2+ units in two layers are he…

Oxygen Transfer from Trimethylamine N ‐Oxide to Cu I Complexes Supported by Pentanitrogen Ligands

2020

[N,N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L1) and [N,N-bis(2-quinolylmethyl)-N-bis(2-pyridyl)methylamine] (L2) were employed to prepare CuII and CuI complexes for spectroscopic and structural characterization. [L1CuII(H2O)](NO3)2 and [L2CuII(NO3)]NO3 have Jahn–Teller distorted octahedral geometries and give rise to isotropic EPR spectra in frozen solution. [L1CuI(CH3CN)]OTf and [L2CuI(CH3CN)]OTf have distorted trigonal bipyramidal and tetrahedral solid-state structures, respectively. The N-donors display labile behavior in solution, based on variable-temperature 1H NMR studies. Addition of trimethylamine N-oxide (Me3NO) to solutions of [L1CuI(CH3CN)]OTf and [L…

2015

The energy barrier to magnetisation relaxation in single-molecule magnets (SMMs) proffers potential technological applications in high-density information storage and quantum computation. Leading candidates amongst complexes of 3d metals ions are the hexametallic family of complexes of formula [Mn6O2(R-sao)6(X)2(solvent)y] (saoH2=salicylaldoxime; X=mono-anion; y=4–6; R=H, Me, Et, and Ph). The recent synthesis of cationic [Mn6][ClO4]2 family members, in which the coordinating X ions were replaced with non-coordinating anions, opened the gateway to constructing families of novel [Mn6] salts in which the identity and nature of the charge balancing anions could be employed to alter the physical…