Département de chimie moléculaire

{The nickel(II) complexes of three unsym. thiosemicarbazone-based ligands featuring a sterically hindered salicylidene (I, 1), aminophenol (II, 2) or thiophenol (III, 3) moiety were synthesized and structurally characterized. The metal ion lies in an almost square planar geometry in all the complexes. The cyclic voltammetry (CV) curve of 1 shows an irreversible oxidn. wave at Eap = 0.49 V, which is assigned to the phenoxyl/phenolate redox couple. The CV curves of 2 and 3 display a reversible one-electron oxidn. wave (E1/2 = 0.26 and 0.22 V vs. Fc+/Fc, resp.) and an one-electron redn. wave (E1/2 = -1.55 and -1.46 V, resp.). The cations 2+ (8) and 3+ (10) as well as the anions 2- (9) and 3- (11) were generated. The EPR spectra of the cations in THF show a rhombic signal at g1 = 2.034