Cobalt in a Bis-β-diketiminate Environment

Abstract

The reaction of Co₂(mesityl)₄ with acetonitrile leads to the formation of a planar, low spin, bis-β-diketiminate cobalt­(II) complex, (1-mesitylbutane-1,3-diimine)₂Co (<b>1</b>). EPR spectroscopy, magnetic studies, and DFT calculations reveal the Co­(II) ion to reside in a tetragonal ligand field with a ²B₂(d_<i>yz</i>)¹ ground state electronic configuration. Oxidation of <b>1</b> with ferrocenium hexafluorophosphate furnishes (1-mesitylbutane-1,3-diimine)₂Co­(THF)₂PF₆ (<b>2</b>). The absence of significant changes in the metal–ligand bond metrics of the X-ray crystal structures of <b>1</b> and <b>2</b> supports ligand participation in the oxidation event. Moreover, no significant changes in C–C or C–N bond lengths are observed by X-ray crystallography upon oxidation of a β-diketiminate ligand, in contrast to typical redox noninnocent ligand platforms