Efficient one- and novel two-photon mechanisms in photocatalysis and bond activation processes

Prof. Dr. Christoph Kerzig, Johannes Gutenberg-Universität Mainz

Many photoreactions suffer from lousy quantum yields owing to poorly understood and chemically unproductive loss channels. To improve
the light-to-chemical-energy conversion efficiencies, we develop new concepts that rely on molecular dyads consisting of a metal complex
unit and a covalently attached organic chromophore. These dyads were employed for efficient key reaction steps in photocatalysis
and a novel approach for controlling the triplet quenching mechanism was established. Guided by our recent study on Coulomb effects
on the energy transfer kinetics, we have developed the Coulombic dyad strategy for obtaining the advantages of molecular dyads without
the time- and resource-consuming synthesis of tailored photocatalysts.
Challenging photoreactions such as light-induced polymerization of hydrogen formation usually require UV light and cannot be driven by one visible photon for thermodynamic reasons.[6,7] With the aim in mind to replace inefficient UV light sources, we are working on different strategies to pool the energy of two visible photons for achieving similar photochemical reactivities as obtained upon direct (one-photon) UV excitation.
All projects are characterized by a synergistic interplay of molecular design, time-resolved optical spectroscopy and lab-scale
irradiation experiments, which allows us to obtain deep mechanistic insights.