Assignment of the oxidation states of Zr and Co in a highly reactive heterobimetallic Zr/Co complex using X-ray absorption spectroscopy (XANES)

Abstract

The reduced heterobimetallic complex (THF)Zr(MesNPⁱPr₂)₃CoN₂ (1) has been examined along with a series of structurally similar reference compounds using X-ray absorption near edge structure (XANES) spectroscopy. Complex 1 has been shown to be highly reactive, often via one-electron pathways that might be expected for a d¹ Zr^III complex. However, the presence of two strongly interacting metals in complex 1 renders the assignment of oxidation states ambiguous. Both Zr and Co K-edge XANES spectra reveal that the most accurate description of complex 1 is that of a Zr^IV/Co^−I zwitterion. Electronic structure calculations support this assignment.