Redox-Active Ligands in Catalysis

Redox-Active Ligands in Catalysis:

Abstract

Nature’s use of redox-active moieties combined with 3d transition-metal ions is a powerful strategy to promote multi-electron catalytic reactions. The ability of these moieties to store redox equivalents aids metalloenzymes in promoting multi-electron reactions, avoiding high-energy intermediates. In a biomimetic spirit, chemists have recently developed approaches relying on redox-active moieties in the vicinity of metal centers to catalyze challenging transformations. This approach enables chemists to impart noble-metal character to less toxic, and cost effective 3d transitional metals, such as Fe or Cu, in multi-electron catalytic reactions.

Juggling with both hands: For sustainable energy, mastering multi-electron catalytic processes is the key feature. To address this challenge, nature combines redox-active metals with redox-active mediators or ligands. The resulting catalytic transformations (e.g. water splitting, CO₂ reduction, CH activation) proceed with low kinetic barriers. This Minireview highlights recent examples of homogeneous catalysis involving redox-active ligands.