Whole series of nanoparticles have now been reported, but probing the competing or coexisting effects in their synthesis and growth remains challenging. Here, we report a bi-nanocluster system comprising two ultra-small, atomically precise nanoclusters, AuAg24(SR)18− and Au2Ag41(SR)26(Dppm)2+ (SR = cyclohexyl mercaptan, Dppm = bis(diphenylphosphino)-methane). The mechanism by which these two nanoclusters coexist is elucidated, and found to entail formation of the unstable AuAg24(SR)18−, followed by its partial conversion to Au2Ag41(SR)26(Dppm)2+ in the presence of di-phosphorus ligands, and an interdependent bi-nanocluster system is established, wherein the two oppositely charged nanoclusters protect each other from decomposition. AuAg24(SR)18 and Au2Ag41(SR)26(Dppm)2 are fully characterized by single crystal X-ray diffraction (SC-XRD) analysis – it is found that their co-crystallization results in single crystals comprising equimolar amounts of each. The findings highlight the interdependent relationship between two individual nanoclusters, which paves the way for new perspectives on nanocluster formation and stability.

Ligand-exchange-induced structure transformation has been exploited as an effective approach to dictate the size and structure of nanoparticles with atomic precision. However, phosphine ligand induced intercluster transformation remains rarely explored....

Halogens have widely served as handles for regulating the growth of nanoparticles and the control of their physicochemical properties. However, their regulatory mechanism is poorly understood. Nanoclusters are the early morphology of nanoparticles and play an important role in revealing the formation and growth of nanoparticles due to their precise structures. Here, we report that halogens induce the anisotropic growth of Ag 40 (C 6 H 5 COO) 13 (SR) 19 (CH 3 CN) (Ag 40 -II, where SR = 4-tert-butylbenzylmercaptan) into Ag 4 5 (C 6 H 5 COO) 1 3 (SR) 2 2 Cl 2 ( Ag 4 5 ), where Ag 4 0 -II is converted from Ag 40 (CH 3 COO) 10 (SR) 22 (Ag 40 -I). Experiments and theoretical simulations showed that halogen ions adsorb at both ends of the cluster, forming defect sites. The -SR-Ag-complexes fill the defects and complete the anisotropic transition from Ag 40 -II to Ag 45 . Circular dichroism spectra show that the chirality of Ag 45 decreases 15-fold compared with that of Ag 40 -II. This work provides important insights into the effects of halogens on the growth mechanism and property regulation for nanomaterials at the atomic level and the benefits of further applications of halogen-induced nanomaterials.

Ultrasmall nanoclusters are emerging nanocatalysts due to their distinct physico-chemical properties. However, the instability and agglomeration of these nanoclusters restrict their practical application. Herein, we designed a negatively charged crosslinked polystyrene (PS) microsphere as support and decorated it with positively charged ultrasmall [Au 4 Cu 5 (Dppm) 2 (C 6 H 11 S) 6 ] + [BPh 4 ] À (Au 4 Cu 5 , in which Dppm stands for bis-(diphenylphos-phino)methane) nanoclusters through strong electrostatic adsorption, as evidenced by X-ray photoelectron spectroscopy. The PS@Au 4 Cu 5 nanocomposites were well-dispersed in water, exhibiting enhanced catalytic activity for the reduction reaction of 4-nitrophenol to produce 4-aminophenol. These findings open promising opportunities for supported nanocluster catalysis. Results and DiscussionThe characterization of Au 4 Cu 5 and PS microspheres Scheme 1 illustrates the synthetic method employed to produce the PS@Au 4 Cu 5 nanocomposites. Firstly, the Au 4 Cu 5