Influence of the ligand field on slow magnetization relaxation versus spin crossover in mononuclear cobalt complexes

Abstract

The electronic and magnetic properties of the complexes [Co(terpy)Cl 2] (1), [Co(terpy)(NCS)2] (2), and [Co(terpy) 2](NCS)2 (3) were investigated. The coordination environment around CoII in 1 and 2 leads to a high-spin complex at low temperature and single-molecule magnet properties with multiple relaxation pathways. Changing the ligand field and geometry with an additional terpy ligand leads to spin-crossover behavior in 3 with a gradual transition from high spin to low spin. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.