Discovering the Balance of Steric and Electronic Factors Needed To Provide a New Structural Motif for Photocatalytic Hydrogen Production from Water

Ru,Rh,Ru supramolecules are known to undergo multielectron photoreduction and reduce H2O to H2. Ru,Rh bimetallics were recently shown to photoreduce but not catalyze H2O reduction. Careful tuning of sterics and electronics for [(TL)2Ru(dpp)RhCl2(TL′)]3+ produce active bimetallic photocatalysts (TL = terminal ligand). The system with TL,TL′ = Ph2phen photocatalytically reduces H2O to H2 while TL,TL′ = phen,bpy or bpy, t Bu2bpy do not.