A DFT computational study of the magnetic behaviour of cobalt dioxolene complexes of tetraazamacrocyclic ligands

Abstract

Density functional theory computational modelling (UTPSSh/6-311++G(d,p)) of the structural and magnetic characteristics of the cobalt dioxolene complexes of 2,11-diaza[3.3](2,6)pyridinophane and tris(2-pyridylmethyl)amine) ligands has been performed. By means of quantum-chemical calculations it has been shown that the nature of exchange interactions between the metal ion and semiquinonate form of the redox-active ligand is determined by the structural peculiarities of tetraazamacrocyclic ligand. The structural parameters responsible for the possibility of the occurrence of spin-crossover and/or valence tautomeric rearrangements have been identified. The calculations testified that correct theoretical representation of magnetic properties of the salt-like transition metal complexes of redox-active ligands requires detailed accounting for their exterior counter-ions.