Advances in the Use of Non-Precious Metal Complexes in Photoredox Catalysis

Visible-light photoredox catalysis has had a paradigm shifting effect on contemporary organic synthesis. The facile conversion of photonic energy into chemical energy provides an alternative molecular activation method, complimentary to traditional thermal methods. The application of ligated metal complexes and organic dyes promotes single electron transfer processes and formation of synthetically useful radical intermediates under mild conditions. This has enabled access to untapped chemical space, novel bond disconnections and increased molecular complexity.

The catalysts used in photoredox processes are typically polypyridyl complexes of heavy (precious) transition metals such as Ru^II or Ir^III or sensitizing organic dyes. However, these systems have several limitations including photostability, environmental sustainability and economics. The application of Earth-abundant, inexpensive 3d transition metal complexes would potentially address these issues, however the intrinsic excited-state lifetimes of these metal complexes are typically very short- much shorter than the Ru or Ir systems. This remains limiting in terms of initiating single electron transfer (SET) events. That said, significant progress has been made in this area over recent years.

This webinar discussed the use of metals as sensitizers for photoredox reactions and how Earth-abundant metal complexes have been designed and developed with the potential to compete with their precious metal cousins. Applications in which Earth-abundant metal complexes give an advantage over existing methods and areas of ongoing research in the field were discussed. Finally, John gave his perspective on future industrial application.

This webinar was presented by Dr John Studley, Scientific Update.