Structural Distortion and Magnetic Behavior in Cyanide‐Bridged Fe^III₂Ni^II₂ Complexes

Abstract

6 pagesInternational audienceThe X-ray structure, spectroscopic, and magnetic properties ofacyanide-bridgedcomplex,{[(Tp*)FeIII(CN)3]2[NiII(bipy)2]2- [OTf]2}*2H2O (2) are described [Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; bipy = 2,2'-bipyridine; OTf = trifluromethanesulfonate]. Magnetic measurements indicate that 2 exhibits an S = 3 ground state and slow relaxation of the magnetization....

Tricyanometalate molecular chemistry: A type of versatile building blocks for the construction of cyano-bridged molecular architectures

“…24), with free perchlorate counter anions. Despite its large structural distortion, the size of the Fe 2 Ni 2 square unit is in agreement with those of cyano-bridged Fe 2 Ni 2 square clusters reported previously [29,[53][54][55][56]. The 1D chains are further linked through hydrogen bonds between perchlorate anions and (1S,2S)-chxn ligands.…”

Cyanide‐Bridged [Fe8M6] Clusters Displaying Single‐Molecule Magnetism (M=Ni) and Electron‐Transfer‐Coupled Spin Transitions (M=Co)

“…All measurements began at 1.8 K and the temperatures were increased. The fresh sample (open circle) showed rapidly increasing c m T values from 1.8 to 11.6 K, followed by a gradual increase to the c m T value of 21.34 emu mol À1 K at 300 K; the value at 300 K is close to the Curie constant (20.34 emu mol À1 K) obtained by summing the uncorrelated spins of eight LS-Fe III (S = 1/2) and six Co II ions (S = 3/2) with the g Fe = 2.7 and g Co = 2.3, [2d, 3b] corresponding with the cluster in the [(LS-Fe 6 ] state. The magnetic susceptibility data suggested that antiferromagnetic interactions between the Fe III and Co II ions were operative and the notable change of the c m T values in the low and intermediate temperature ranges might be due to the orbital contribution from the metal ions.…”

“…It is, therefore, assumed that three electrons were transferred from the [(LS-Fe 6 ] states upon the temperature increase. Note that no hysteresis was observed for desolvated 2.…”

“…The HL ligand has a proton donor site on the pyrazole moiety that can form intramolecular hydrogen bonds, while its bulky triaryl amine substituent is expected to separate molecules by hindering intermolecular hydrogen bonds. Herein we report the syntheses and magnetic properties of two novel heterometal clusters, [Fe 8 M 6 (CN) 24 (tp) 8 (HL) 10 6 ] 4 ·nCH 3 CN·mH 2 O (1: M= Ni, n = 11, m = 7 and 2: M= Co, n = 14, m = 5; tp À = hydrotris(pyrazolylborate)), which exhibit SMM and ETCST behaviors, respectively. [2e] and nBu 4 NPF 6 in CH 3 CN.…”

“…The solid lines were calculated Lorentzian curves by using the parameters in the text. 6 ] occurred, which then thermally relaxed to the LT phase upon temperature increase. The light conversion ratio was 0.76, supposing g Fe = 2.7 and g Co = 2.3, respectively.…”