A dinuclear Re Complex as a Multi Talent – Photocatalysis and Electrocatalysis combined with Spectroscopy

Mononuclear rhenium complexes have been widely studied as photo‐ and electrocatalysts. However, dinuclear systems with cooperative properties have rarely been investigated. On the basis of two homobimetallic rhenium complexes, we report the synthesis and characterization of two isomers and their photo‐ and electrochemical properties. By combining the respective isomer with the photosensitizer [Ir(dFppy)3] (Ir, dFppy=2‐(4,6‐difluorophenyl) pyridine)) enhanced CO2 to CO transformation could be observed and by further spectroscopic investigations the reaction mechanism could be fathomed. The observed enhanced catalytic activity compared to monometallic systems derives from the cooperative Re‐Re interaction through two electron reduction on the complex (and thereby formation of an intermediate species with a Re‐Re bond). Using LSV measurements the cooperative CO2 activation was also observed in electrocatalytic measurements. The two isomers have a somewhat lower catalytic activity than earlier prepared geometric isomers, but show better catalytic properties than their mononuclear counterpart.