Pincer complexes in photo- and electro-catalytic hydrogen evolution (HER) and carbon dioxide reduction reactions (CO2RR)

Pincer complexes have aided in the understanding of a number of processes mediated by transition metal compounds. In homogenous catalytic transformations, pincers as ligands provide enhanced chemical and thermal stability which serve to minimize the leaching of the metal during the catalytic cycle. The electronic and the steric properties of pincer ligands can be independently fine-tuned, thereby increasing the scope of their ap-plications. Pincer complexes are being explored as tools in the quest for solving the global energy crisis and methods of slowing climate change viz sequestering CO2. In this review, the complexes are organized according to the coordinating atoms from the pincer ligand. We will explore some of the progress in made in recent years towards photo-and electro-catalytic hydrogen evolution reaction (HER), and the carbon dioxide reduction re-action (CO2RR) by pincer complexes. The review focuses on reports within the last 12 years, and, where possible, emphasises how modifications to the ligand framework (or reaction conditions) impacts the efficacy of the resulting pincer complexes.