Heteroleptic iron(III) Schiff base spin crossover complexes: halogen substitution, solvent loss and crystallite size effects

Abstract

The influence of the halogen substituent on the qsal moiety of iron(iii) heteroleptic compounds with the formulae [Fe(qsal-X)(thsa)]·nMeCN, where qsal-X- = X-substituted quinolylsalicylaldimine; thsa2- = thiosemicarbazone-salicylaldiminate; X = F; n = 2.5, 1·2.5MeCN and X = Cl 2, Br 3 and I 4, n = 1 (labelled 2·MeCN, 3·MeCN and 4·MeCN, respectively) has been systematically investigated. Magnetic studies on solid samples show incomplete spin crossover in 1-3 which can be related to MeCN solvent loss. Complex 4·MeCN remains fully LS up to 360 K. Single crystals have been examined at variable temperatures for samples possessing different degrees of solvation. Intermolecular C-XH interactions ar..