Quantum-chemical study of spin crossover in cobalt complexes with an o-benzoquinone ligand

Abstract

Quantum-chemical modeling of cationic cobalt complexes based on o-benzoquinone and a di-tert-butyl derivative of 2,11-diaza[3.3](2,6)pyridinophane was performed by the density functional theory method in the TPSSh/6-311++G(d,p) approximation. The ground states of the studied compounds are lowspin structures consisting of the divalent metal cation and a redox-active ligand in the semiquinone form. The calculations predict incomplete transition of these complexes to the high-spin state, which is consistent with the results of magnetochemical measurements.