Kinetic studies of photoinduced methyl viologen reduction with ruthenium complexes and hydrogen evolution from water by hydrogenase

Abstract

Highly active photoinduced systems for methyl viologen reduction have been developed by using ruthenium complexes with long lifetimes in the photoexcited state. The order of activities is as follows: Ru(dime-phen)²⁺₃ > Ru(Cl-phen)²⁺₃ > Ru(phen)²⁺₃ > Ru(bpy)²⁺₃. By kinetic studies the rate constants for quenching the excited ruthenium complexes by methyl viologen have been determined. When hydrogenase was added to the systems containing ruthenium complex, methyl viologen and reducing agent, hydrogen evolution was observed in every system. A higher activity for hydrogen evolution was observed for the system having a higher activity for methyl viologen reduction.