Single molecule magnet behaviour in a square planar S = 1/2 Co(ii) complex and spin-state assignment of multiple relaxation modes

Abstract

We report the first example of field-induced single molecule magnet (SMM) behaviour in a square-planar S = 1/2 Co(II) pincer complex [(P^NN^NP)CoBr]Br (2). The related five-coordinate complexes [(P^CN^CP)CoBr₂] (1) and [(P^ON^OP)CoBr₂] (3) also exhibit SMM properties. Partial spin crossover displayed by 3 allows for assignment of distinct relaxation modes to each spin state.