O2Activation by a Heterobimetallic Zr/Co Complex

Abstract

Oxygen reduction is a critical half reaction in renewable fuel cell development and a key step in the development of aerobic oxidation reactions. Herein, we report rapid two-electron O2reduction by a d0ZrIVcenter with an appended redox-active Co-Isite serving as an electron reservoir. The early/late heterobimetallic Zr/Co complex (THF)Zr(MesNPiPr2)3CoCNtBu (1) reacts readily with O2and O atom transfer reagents to generate reactive oxygenated species including terminal peroxo and oxo complexes, (O2)Zr(MesNPiPr2)3CoCNtBu (2) and OZr(MesNPiPr2)3CoCNtBu (3). The bimetallic Zr/Co complex provides a new cooperative synthetic pathway to promote multielectron redox processes such as oxygen reduction, with each metal playing a distinct role as a substrate binding site or redox mediator.