Synthesis and Characterization of Tris(oxazolinyl)borato Copper(II) and Copper(I) Complexes

Abstract

The reaction of ToMTl (ToM=tris(4,4‐dimethyl‐2‐oxazolinyl)phenylborate) and CuBr2 in benzene at 60 °C provides ToMCuBr (1) as an entry‐point into tris(oxazolinyl)phenylborato copper chemistry. ToMCuOtBu (2) and ToMCuOAc (3) are prepared by the reactions of ToMCuBr with KOtBu and NaOAc, respectively. ToMCuOtBu is transformed into (ToMCuOH)2 (4) through hydrolysis. NMR, FT‐IR, and EPR spectroscopies are used to determine the electronic and structural properties of these copper(II) compounds, and the solid‐state structures were characterized by X‐ray crystallography. Reduction of copper is observed upon treatment of ToMCuOtBu with phenylsilane in an attempt to synthesize monomeric copper(II) hydride. ToMCu (5) and ToM2Cu (6) were independently synthesized and characterized for comparison.