Synthesis and Light-Driven Hydrogen Evolution of Mono-and Bis-Platinum Terpyridine Complexes Based on a Carbon-Bridged Distyrylbenzene Chromophore

Mono-and bis-platinum terpyridine complexes based on a carbon-bridged oligo(p-phenylenevinylene) chromophore were synthesized and evaluated in the photocatalytic hydrogen evolution reaction. Both complexes retained visible absorption derived from the rigid chromophore and promoted hydrogen formation under visible-light irradiation at wavelengths of >400 nm in the presence of water and triethylamine. The mono-platinum complex exhibited a higher turnover number per platinum center than the bis-platinum analogue and the parent platinum complex, supporting a beneficial light-harvesting contribution of the carbon-bridged chromophore. Mercury-poisoning experiments and electron microscopy indicated that platinum species evolve during irradiation, including formation of platinum nanocrystals.These results show that carbon-bridged phenylenevinylene can act as an effective visible-light-absorbing unit in platinum-based photocatalytic systems.