Results
Title

Unraveling the Light‐Activated Reaction Mechanism in a Catalytically Competent Key Intermediate of a Multifunctional Molecular Catalyst for Artificial Photosynthesis.

Authors

Zedler, Linda; Mengele, Alexander Klaus; Ziems, Karl Michael; Zhang, Ying; Wächtler, Maria; Gräfe, Stefanie; Pascher, Torbjörn; Rau, Sven; Kupfer, Stephan; Dietzek, Benjamin

Abstract

Understanding photodriven multielectron reaction pathways requires the identification and spectroscopic characterization of intermediates and their excited‐state dynamics, which is very challenging due to their short lifetimes. To the best of our knowledge, this manuscript reports for the first time on in situ spectroelectrochemistry as an alternative approach to study the excited‐state properties of reactive intermediates of photocatalytic cycles. UV/Vis, resonance‐Raman, and transient‐absorption spectroscopy have been employed to characterize the catalytically competent intermediate [(tbbpy)2RuII(tpphz)RhICp*] of [(tbbpy)2Ru(tpphz)Rh(Cp*)Cl]Cl(PF6)2 (Ru(tpphz)RhCp*), a photocatalyst for the hydrogenation of nicotinamide (NAD‐analogue) and proton reduction, generated by electrochemical and chemical reduction. Electronic transitions shifting electron density from the activated catalytic center to the bridging tpphz ligand significantly reduce the catalytic activity upon visible‐light irradiation.

Subjects

ARTIFICIAL photosynthesis; CHEMICAL reduction; ELECTRON density; CATALYTIC activity; ELECTRON transitions; PHOTOCATALYSTS; HYDROGENATION; ELECTROLYTIC reduction

Publication

Angewandte Chemie, 2019, Vol 131, Issue 37, p13274

ISSN

0044-8249

Publication type

Academic Journal

DOI

10.1002/ange.201907247