Asymmetric catalysis promoted by hierarchical chirality of metal nanoclusters

Asymmetric catalytic reactions, in which diverse enantioselective catalysts have been developed for maximizing turnover number and enantiomeric excess, serve as the cornerstone strategy for achieving molecular stereoselectivity in fine chemicals and pharmaceutical industry. In recent years, chiral metal nanoclusters (NCs) have emerged as a cutting-edge research frontier in asymmetric catalysis due to their precisely tunable structural attributes at the unprecedented atomic level, as well as their hierarchical structures reminiscent of natural proteins. It has become known that chirality can emerge at diverse structural hierarchies, including metal core, metal-ligand interface, ligand body, and assembly patterns of metal NCs, offering an ideal platform to not only boost the catalytic activity but also understand the catalytic mechanism in asymmetric reactions. This review systematically summarizes recent progress in the synthesis and asymmetric catalytic applications of chiral metal NCs, based on their core-shell structure scheme. The discussion starts with a brief elaboration on the structural origin of cluster chirality, followed by a concise account of the synthetic methodologies delivering enantiopure metal NCs. Before concluding this review with our perspectives on metal NCs-based asymmetric catalysis, the catalytic applications of chiral metal NCs are outlined. The fundamental and applicable advances summarized in this review should be useful for designing chiral metal NCs for asymmetric catalytic applications.