Photosubstitution reactions in ruthenium(II) trisdiimine complexes: Implications for photoredox catalysis

Ruthenium(II) trisdiimine complexes, including polypyridine complexes, have found many applications in the past decade as photoredox catalysts for organic transformations. This review article highlights the ability of these types of complexes to undergo photo-induced ligand exchange reactions, especially by anions. This property has been well known for decades but is generally overlooked when exploring reaction conditions for photoredox reactions. The demonstrated ability of common ruthenium(II) complexes to undergo ligand exchange reactions is surveyed, the accepted means of predicting this stability, as well as possible future directions in photoredox catalysis, is discussed. (C) 2018 Elsevier Ltd. All rights reserved.