Charge and spin coupling in copper compounds with hemilabile noninnocent ligands - Ambivalence in three dimensions

Both the copper(I) and copper(II) states exhibit coordinative ambiguity as well as a typically increased coordination number after oxidation. This tendency can be used in dynamic redox systems, employing hemilabile innocent ligands. With noninnocent hemilabile ligands such as thioether- or selenoether-substituted o-semiquinone imines there is a complementary reactivity on the ligand side, viz., stepwise electron transfer and coordinative ambivalence. Some resulting combinations have been analyzed for two systems, involving one copper center and one camphorquinone imine or two o-benzoquinone imine components (Q(n)). Combining redox (Cu-I/II, Q0/(center dot-/2-)) and coordinatively ambivalent metal and ligand components (hemilability) creates variable electronic situations which require experimental and theoretical analysis. (C) 2017 Elsevier B.V. All rights reserved.