Cp*–‐Ruthenium–Nickel‐Based H2‐Evolving Electrocatalysts as Bio‐inspired Models of NiFe Hydrogenases

Abstract

AbstractThree dinuclear nickel–ruthenium complexes [Ni(xbsms)RuCp*(L)](PF6) [H2xbsms = 1,2‐bis(4‐mercapto‐3,3‐dimethyl‐2‐thiabutyl)benzene; Cp* = pentamethylcyclopentadienyl; L = CH3CN, CO and O2] are reported that act as bio‐inspired mimics of NiFe hydrogenases. Because of an increased electron density at the metal centres in comparison with the previously described [Ni(xbsms)RuCp(L)](PF6) (Cp = cyclopentadienyl) analogues, these compounds catalyze the evolution of hydrogen from Et3NH+ in DMF with an overpotential reduced by around 50 mV, thereby corroborating a previously established structure–function relationship [Eur. J. Inorg. Chem. 2007, 18, 2613–2626; Chem. Eur. J. 2009, 15, 9350–9364]. In addition, the steric protection provided by the bulky Cp*– ligand results in an increased catalytic rate and stability upon cycling.