Nickel model complexes to mimic carbon monoxide dehydrogenase reactions.

Biological CO/CO interconversion catalyzed at the Ni/Fe heterobimetallic active site of anaerobic carbon monoxide dehydrogenases (CODHs) offers important insights for the design of efficient and selective synthetic catalysts for CO capture and utilization (CCU). Notably, this organometallic C interconversion process is mediated at a three-coordinate nickel site. Extensive research has been conducted to elucidate the redox and structural changes involved in substrate binding and conversion. The CO-bound structure of CODH, in particular, has inspired many synthetic studies aimed at exploring key questions, concerning the choice of metal, the role of the unique iron (Fe), and the geometry and oxidation states of both Ni and Fe, as well as CO/CO exchange mechanism. A better understanding of CODH chemistry promises to reveal and uncover fundamental principles for small molecule activation of first-row transition metal complexes. This mini-review focuses on three key aspects: (1) the coordination environment of the Ni centre in CODH, (2) bioinorganic Ni model systems that provide insight into the biological CO/CO interconversion at the CODH active site, and (3) recent advances in CODH-inspired catalysis for selective CO-to-CO conversion.