Exchange and Double-Exchange Phenomena in Linear Homo- and Heterotrinuclear Nickel(II,III,IV) Complexes Containing Six μ2-Phenolato or μ2-Thiophenolato Bridging Ligands

Abstract

A series of homo- and heterotrinuclear complexes containing three face-sharing octahedra has been synthesized by using the pendent arm macrocyclic ligands 1,4,7-tris(3,5-dimethyl-2-hydroxybenzyl)-1,4,7-triazacyclononane, L0H3, and 1,4,7-tris(4-tert-butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane, LH3: [{L0NiII}2NiII] (1) and [{LCoIII}2CoIII](PF6)3 (2); [{LCoIII}2Ni]n+ (n = 2 (3), 3 (4), 4 (5)); [{LNi}2CoIII]n+ (n = 1 (6), 2 (7), 3 (8)) and its linkage isomers [{LNi}Ni{CoIIIL}]n+ (n = 1 (9), 2 (10), 3 (11)) and, finally, the complexes [{LNi}2Ni]n+ (n = 0 (12), 1 (13), 2 (14), 3 (15)). In complex 1 three octahedral NiII ions form a linear array with two terminal [L0NiII]- moieties in a facial N3O3 donor set and a central NiII ion which is connected to the terminal ions via six phenolate bridging pendent arms of L0. In complexes 2−15 the three metal ions are always in the same ligand matrix yielding an N3M(μ-S)3M(μ-S)3MN3 first-coordination sphere regardless of the nature of the metal ions (nickel or cobalt...