Abstract

The investigation into the active copper(I) catalysts from copper(II) precursors has become a fundamental and important task in copper catalysis. In this work, we demonstrate that the (BuO-)-Bu-t anion serves not only as a base but also as a mediator to promote the reduction of Cu(II) to Cu(I) in copper catalysis. XAFS and EPR spectroscopy evidence the [Cu((OBu)-Bu-t)(3)](-) ate complex as the key intermediate which undergoes homolytic-cleavage of the O-Cu(II) bond generating [Cu(O(t)Bu())2](-) ate complex.