Recent advances in the synthetic chemistry of atomically precise metal nanoclusters (NCs) have significantly broadened the accessible sizes and structures. Such particles are well defined and have intriguing properties, thus, they are attractive for catalysis. Especially, those NCs with identical size but different core (or surface) structure provide unique opportunities that allow the specific role of the core and the surface to be mapped out without complication by the size effect. Herein, we summarize recent work with isomeric Aun NCs protected by ligands and isostructural NCs but with different surface ligands. The highlighted work includes catalysis by spherical and rod‐shaped Au25 (with different ligands), quasi‐isomeric Au28(SR)20 with different R groups, structural isomers of Au38(SR)24 (with identical R) and Au38S2(SR)20 with body‐centred cubic (bcc) structure, and isostructural [Au38L20(PPh3)4]2+ (different L). These isomeric and/or isostructural NCs have provided valuable insights into the respective roles of the kernel, surface staples, and the type of ligands on catalysis. Future studies will lead to fundamental advances and development of tailor‐made catalysts.

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Crystallization-induced emission enhancement was achieved in metal nanoclusters for the first time.

Hydrolysis of ammonia-borane (AB) is one of the most convenient sources of H 2 under ambient conditions, but the reaction requires a good catalyst to become efficient. Here this reaction is catalyzed by bimetallic late transition-metal nanoparticles (NPs) stabilized by "click" dendrimers 1 and 2 containing respectively 27 or 81 terminal triethylene glycol termini and 9 or 27 intradendritic 1,2,3-triazole ligands. A remarkable synergy between Pt and Co in the Pt-Co/"click" dendrimer nanocatalyst is disclosed. These Pt-Co/"click" dendrimer catalysts are much more efficient for hydrolysis of AB than either "click" dendrimer-stabilized Co or Pt analogues alone. The best catalyst Pt 1 Co 1 /1 stabilized by the nona-triazole "click" dendrimer 1 achieves a TOF of 303 mol H2 •mol catal.-1 •min-1 (606 mol H2 •mol Pt-1 •min-1) at 20 ± 1°C. In the presence of NaOH, the reactivity is boosted for hydrolysis of AB catalyzed by Pt 1 Co 1 /1, and reaches a TOF value of 476.2 mol H2 •mol catal.-1 •min-1 (952.4 mol H2 •mol Pt-1 •min-1), one of the very best results obtained by comparison with the literature. The presence of a percentage of Pt as low as 25% in the CoPt nanoalloy provides a reaction rate higher than with that obtained with the pure Pt NP catalyst alone. The kinetics involves in particular a kinetic isotope effect k D /k H = 2.46 obtained for the hydrolysis reaction with D 2 O, suggesting O-H bond cleavage of water in the rate-determining step. Tandem reactions were conducted for the hydrogenation of styrene with hydrogen generated from the hydrolysis of AB. Performing this tandem reaction with D 2 O shows deuteration of the ethylbenzene products confirming O-D cleavage and H/D scrambling on the bimetallic nanoparticle surface. Finally a reaction mechanism is proposed. This dramatic synergy type should also prove useful in a number of other catalytic systems.

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The crystal structure of selenolate-capped Au25(SePh)18(-) nanoclusters has been unambiguously determined for the first time, and provides a solid basis for a deeper understanding of the structure-property relationships. The selenolate-capped Au25 cluster shows noticeable differences from the previously reported Au25(SCH2CH2Ph)18(-) counterpart, albeit both share the icosahedral Au13 core and semi-ring Au2(SeR)3 or Au2(SR)3 motifs. Distinct differences in the electronic structure and optical, catalytic and electrochemical properties are revealed by the coupling experiments with density functional theory (TD-DFT) calculations. Overall, the successful determination of the Au25(SePh)18(-) structure removes any ambiguity about its structure, and comparison with the thiolated Au25 counterpart helps us to further understand how the ligands affect the properties of the nanocluster.

Ultrasmall nanoclusters (e.g., Au(SR)) are crucial in not only real applications such as bioapplication but also in understanding the structure transition from gold complexes to gold nanoclusters. However, the determination of these transition-sized gold nanoclusters has long been a major challenge. In this work, two new nanoclusters in the transition regime, including the thus far smallest thiolated alloy nanocluster CdAu(S tBu) and the homogold nanocluster Au(S-Adm), are obtained and their atomic structures are fully determined by single crystal X-ray diffraction. Moreover, based on the structures of CdAu(SR) and Au(SR), we perform DFT calculations to predict the structure of the "transformation" nanocluster, Au (Au(SR) and Au(SR)). Overall, this work bridges the gaps between gold complexes and nanoclusters.

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