0000000000004715
AUTHOR
Marie-laure Boillot
A wide family of pyridoxal thiosemicarbazone ferric complexes: Syntheses, structures and magnetic properties
Abstract This study reports the syntheses and the characterization of 12 ferric complexes of pyridoxal thiosemicarbazone. The richness of the coordination chemistry of this ligand is highlighted by the modulation of its charge from neutral H 2 L to anionic L 2− , thus leading to a wide family of ferric compounds with charge varying from +3 to −1. The structures of complexes [Fe(HL) 2 ]ClO 4 · 2H 2 O and [Fe(HL)L] · 4.5H 2 O were solved and discussed with a particular attention brought to the intermolecular interactions occurring between the complexes. The investigation of magnetic properties of these compounds revealed that two of them are in the HS state at any temperature, whereas the ot…
Photomagnetic effect in a cyanide-bridged mixed-valence {FeII2FeIII2} molecular square
The self-assembly of [Fe(III)(Tp)(CN)(3)](-) and [Fe(II)(bik)(2)(S)(2)](2+) affords the cyanide-bridged mixed valence {Fe(III)(2)Fe(II)(2)}(2+) molecular square, which exhibits a photomagnetic effect under laser light irradiation at low temperature and also shows thermal spin-state conversion near ambient temperature.
Electronic, vibrational, and structural properties of a spin-crossover catecholato-iron system in the solid state: theoretical study of the electronic nature of the doublet and sextet states.
As a functional model of the catechol dioxygenases, [(TPA)Fe(Cat)]BPh4 (TPA = tris(2-pyridylmethyl)amine and Cat = catecholate dianion) exhibits the purple-blue coloration indicative of some charge transfer within the ground state. In contrast to a number of high-spin bioinspired systems, it was previously shown that, in the solid state, [(TPA)Fe(Cat)]BPh4 undergoes a two-step S = 1/2 = S = 5/2 spin-crossover. Therefore, the electronic and vibrational characteristics of this compound were investigated in the solid state by UV/Vis absorption and resonance Raman spectroscopies over the temperature range of the transition. This allowed the charge-transfer transitions of the low-spin (LS) form …
Spin crossover of ferric complexes with catecholate derivatives. Single-crystal X-ray structure, magnetic and Mössbauer investigations.
Complexes of general formula [(TPA)Fe(R-Cat)]X·nS were synthesised with different catecholate derivatives and anions (TPA = tris(2-pyridylmethyl)amine, R-Cat2− = 4,5-(NO2)2-Cat2− denoted DNC2−; 3,4,5,6-Cl4-Cat2− denoted TCC2−; 3-OMe-Cat2−; 4-Me-Cat2− and X = BPh4−; NO3−; PF6−; ClO4−; S = solvent molecule). Their magnetic behaviours in the solid state show a general feature along the series, viz., the occurrence of a thermally-induced spin crossover process. The transition curves are continuous with transition temperatures ranging from ca. 84 to 257 K. The crystal structures of [(TPA)Fe(DNC)]X (X = PF6−; BPh4−) and [(TPA)Fe(TCC)]X·nS (X = PF6−; NO3− and n = 1, S = H2O; ClO4− and n = 1, S = H…