Highly Efficient Photocatalytic Water Reduction with Robust Iridium(III) Photosensitizers Containing Arylsilyl Substituents

摘要

As initiated by the pioneering studies of the Bernhard research group enormous advances in cyclometalated Ir~(III) photosensitizers have been made in the pursuit of highly efficient visible-light-driven water-reduction systems. Many different classes of cationic Ir~(III) photosensitizers have been developed with the general structure [Ir~(III)(C^N)2-(N^N)]~+, in which C^N is a monoanionic cyclometalating ligand and N^N is a neutral ancillary ligand. Photocatalytic water-reduction systems are typically benchmarked in terms of their turnover number (TON), which reflects the stability of the system under the operating conditions and is thus deeply related to the monetary expense for solar-to-hydrogen energy conversion. DiSalle and Bernhard designed a series of Ir~(III) photosensitizers with pendant pyridine moieties, which directed the adsorption of the complexes onto a colloidal platinum catalyst to generate H2 with a TON value of 8800.