Cobalt in a Bis-β-diketiminate Environment

The reaction of Co-2(mesityl)(4) with acetonitrile leads to the formation of a planar, low spin, bis-beta-diketiminate cobalt(II) complex, (1-mesitylbutane-1,3-diimine)(2)Co (1). EPR spectroscopy, magnetic studies, and DFT calculations reveal the Co(II) ion to reside in a tetragonal ligand field with a B-2(2)(d(yz))(1) ground state electronic configuration. Oxidation of 1 with ferrocenium hexafluorophosphate furnishes (1-mesitylbutane-1,3-diimine)(2)Co(THF)(2)PF6 (2). The absence of significant changes in the metal ligand bond metrics of the X-ray crystal structures of 1 and 2 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 beta-diketiminate ligand, in contrast to typical redox noninnocent ligand platforms.