Four-coordinate Co(ii) and Fe(ii) complexes with bis(N-heterocyclic carbene)borate and their magnetic properties†
Abstract
Both square planar and tetrahedral isomers of the four-coordinate complex [Co(BctBu)2] with a bis(3-tert-butylimidazol-2-ylidene)borate ligand (BctBu) have been isolated while only a tetrahedral configuration was found for the Fe(II) analogue [Fe(BctBu)2]. Novel co-crystals containing both isomers of [Co(BctBu)2] have been obtained from recrystallization.