A Structurally Diverse Ru II ,Pt II Tetrametallic Motif for Photoinitiated Electron Collection and Photocatalytic Hydrogen Production

Coupling a reactive metal to light absorbers affords molecular devices for photoinitiated electron collection and photocatalytic conversion of substrates to fuels. A new Ru II ,Pt II tetrametallic supramolecule, [{(phen) 2 Ru(dpp)} 2 Ru(dpq)PtCl 2 ](PF 6 ) 6 , and the trimetallic precursors, [{(phen) 2 Ru(dpp)} 2 RuCl 2 ](PF 6 ) 4 and [{(phen) 2 Ru(dpp)} 2 Ru(dpq)](PF 6 ) 6 , have been synthesized, and their redox, spectroscopic, spectroelectrochemical, photophysical and photocatalytic properties studied. They efficiently absorb UV and visible light. The electrochemistry of [{(phen) 2 Ru(dpp)} 2 Ru(dpq)PtCl 2 ](PF 6 ) 6 suggests a lowest‐lying terminal Ru→dpq charge‐separated state that quenches the emission of the parent complex with non‐unity population of the emissive 3 M LCT excited state. Photolysis of [{(phen) 2 Ru(dpp)} 2 Ru(dpq)PtCl 2 ] 6+ at 470 nm with DMA gives multielectron reduction, storing electrons in a new manner on the central (dpp) 2 Ru II (dpq) moiety. Addition of H 2 O to the photolysis system produces 21 μmol of H 2 in 5 h, with 115 turnovers of the tetrametallic photocatalyst.