Six-coordinate ruthenium water oxidation catalysts bearing equatorial polypyridinedicarboxylato and axial phosphine ligands

Ruthenium catalysts for water oxidation combining multidentate ligands [2,2′:6′,2″-terpyridine]-6,6″-dicarboxylato (tda) and 2,2′-bipyridine-6,6′-dicarboxylato (bda) with apical phosphine have been prepared. These new complexes were fully characterized by standard spectroscopic single-crystal X-ray crystallography analyses, their redox properties evaluated electrochemistry. Specifically, [RuII(tda)(tris(2-furyl)phosphine)2] displayed two reversible waves that assigned to the RuII/III RuIII/IV transitions, respectively. The number of turnovers in CeIV-driven reached 258 bda analog, tda early reaction rates first order initial catalyst concentration. effects adding fractional equivalents CeIV studied using UV–vis spectroscopy. Steric electronic changes axial ligand can exert on catalytic activity resulting complexes, which may be useful when exploring other chemistry these complexes.