Efficient Light-Driven Water Oxidation Catalysis by Dinuclear Ruthenium Complexes

Dr. Serena Berardi, Dr. Laia Francas, Sven Neudeck, Dr. Somnath Maji, Dr. Jordi Benet-Buchholz, Prof. Dr. Franc Meyer, Prof. Dr. Antoni Llobet

Abstract

Mastering the light-induced four-electron oxidation of water to molecular oxygen is a key step towards the achievement of overall water splitting to produce alternative solar fuels. In this work, we report two rugged molecular pyrazolate-based diruthenium complexes that efficiently catalyze visible-light-driven water oxidation. These complexes were fully characterized both in the solid state (by X-ray diffraction analysis) and in solution (spectroscopically and electrochemically). Benchmark performances for homogeneous oxygen production have been obtained for both catalysts in the presence of a photosensitizer and a sacrificial electron acceptor at pH 7, and a turnover frequency of up to 11.1 s⁻¹ and a turnover number of 5300 were obtained after three successive catalytic runs. Under the same experimental conditions with the same setup, the pyrazolate-based diruthenium complexes outperform other well-known water oxidation catalysts owing to both electrochemical and mechanistic aspects.

http://onlinelibrary.wiley.com/doi/10.1002/cssc.201500798/full