Synthesis Of Chiral Ag₃₂ And Ag₄₅ Nanoclusters

The atomic precise nanoclusters made of noble metals have become a new and novel subject because of their unique chemical properties.In the past few decades,investigations of noble metal nanoclusters have been strongly motivated by their extensive applications,such as catalysis,doping,sensing,biomedicine,and photovoltaics.In many cases,it has been shown that the well-defined atomic structure of nanoclusters is a key factor determining their unique physical and chemical properties.However,the lack of suitable characterization techniques has impeded the fundamental understanding of the atom packing model in nanoclusters,particularly in the metal-ligand interface.Therefore,the determination of the overall structure of metal nanoclusters remains a big challenge in cluster chemistry.At the same time,the adjustment of the surface ligands of the metal nanoclusters is of vital importance to regulate their sizes,structures and properties at the atomic level.Herein,based on the previous research,we report the synthesis of two silver nanoclusters[Ag32(Dppm)5(SAdm)13Cl8]3+ and[Ag45(Dppm)4(S-But)16Br12]3+,and an alloy cluster of[Ag20Cu12(SR)14(Dppm)6Br8]2+ by using multi-ligand-induced synthetic strategy.The main contents are as follows:1.We have attempted to synthesize two chiral silver nanoclusters of[Ag32(Dppm)5(SAdm)13Cl8]3+ and[Ag45(Dppm)4(S-But)16Br12]3+(Dppm = double diphenyl phosphine methane,SAdm-1-adamantane mercaptan,S-But = tertiary butyl mercaptan).The total structures and compositions of the as-prepared silver clusters have been analyzed by single-crystal X-ray diffraction and X-ray photoelectron spectroscopy,respectively.In this paper,the combined use of phosphine,thiol and halogen could ensure the success of two chiral silver nanoclusters.[Ag32(Dppm)5(SAdm)13Cl8]3+ has a achiral Ag13 kernel,and the structure is surrounded by asymmetric Ag19S13Cl8P10 motif.For[Ag45(Dppm)4(S-But)16Br12]3+,the Ag23 kernal is composed of two Ag13 cores by sharing three Ag atoms in the same plane,and the kernal is surrounded by Ag22Si6PsBri2 motif.Interestingly,the whole structure is similar to the crab.This method will provide insights into the synthesis of more chiral silver nanoclusters in the future.2.[Ag20Cu12(SR)14(Dppm)6Br8]2+ alloy nanoclusters were also obtained by using three types of ligands(thiolate,phosphine,and halogen).This cluster has a Ag17 core and two AgiCu6(SR)7(Dppm)3Br4 staples are connected by one Ag atom to construct the bigger Ag3Cui2(SR)14(Dppm)6Br8 motif,which surround the kernal.In this motif,the ?-? function between the two benzene ring of the thiols makes the structure closed and the whole more stable.Notably,this cluster has the same 32 metal atom numbers as[Ag32(Dppm)5(SAdm)13Cl8]3+.However,the difference in ligands or metals makes the two clusters possess diverse qualities and structures.This synthetic strategy will have great implications for the synthesis of Ag-based alloy clusters.