A Cobalt Complex from Terpyridine-Based Peptoid as an Efficient Catalyst for Visible Light Driven Water Oxidation

Abstract

We report on the first peptoid-based catalyst for visible light driven water oxidation, the complex TPT2Co. Peptoids are N-substituted glycine oligomers, and TPT is a peptoid trimer incorporating terpyridine ligand, an ethanolic group as a proton acceptor and a non-catalytic benzyl group. We explored the ability of TPT2Co to perform as a catalyst for water oxidation in phosphate buffer at pH 9.5, in the presence of the photosensitizer [Ru(bpy)3]2+ and the sacrificial electron acceptor Na2S2O8. We demonstrated that TPT2Co can catalyze water oxidation by a blue LED with an intensity of only 1.5 mW/cm2 towards oxygen production at pH 9.5 with a maximal TON of 28.1 in 45 min. The stability of TPT2Co during the light-driven water oxidation as well as its ability to stabilize the photosensitizer were confirmed by a combination of UV-Vis, IR and ESI-MS analysis.