Unsymmetrical dirhodium single molecule photocatalysts for H2 production with low energy light.

New axially blocked unsymmetrical dirhodium complexes photocatalyze the production of H2 under red light irradiation with a turnover number (TON) of 23 ± 3 in the presence of acid and a sacrificial donor. The presence of multiple metal/ligand-to-ligand charge transfer transitions improves their absorption of light into the near-IR.