Synthesis,Structure And Properties Of Phosphines,Alkynes Protected Coinage Metal Nanoclusters

Atomically precise,ligand-protected coinage metal nanoclusters have attracted strong attention not only because of their amazing structures and properties,but also owing to their potential applications in catalysis,luminescence and biology.This dissertation focuses on increasing the structural models of coinage metal nanoclusters,enriching our understanding of the coordination modes of ligands,and testing the catalytic application of the nanoclusters.We utilized multidentate diphosphine ligand(dppp)as a protection,owing to which we synthesized a series of novel gold nanoclusters protected by Cl and dppp ligands.We observed the dppp ligands forming dpppAu3 motif leaving a gold atom vacant which could be regarded as a potential active site for catalysis.Also we synthesized a Au45 nanocluster for the first time which was larger than the largest previously reported structurally determined phosphine-protected gold nanocluster.And we found Cl was essential to synthesize the Au45 cluster,which was helpful to synthesize the novel phosphine-protected gold nanocluster.By comparing the structures,optical properties and stability of two Au20 nanoclusters,we found that the diphosphine ligands had an influence on the location of ligands and the structures of the Au20 kernels and then changing the optical properties and stability of the Au20 clusters.By direct reduction method,we synthesized a series of alkynyl-protected coinage metal nanoclusters.For the first time,we observed the L-shaped PhC=C-Au-P staple motif in Au40 nanocluster,which showed a new coordination mode of the phosphine ligands.In addition,the linear PhC?C-Au-C?CPh staple motif was observed and it was demonstrated that the steric hindrance of the adjacent ligands had a great effect on the shape of the staple motifs by comparing the structures of staple motifs in Au40 and Au38 nanoclusters.We explored the Au40 cluster as a catalyst for chemoselective hydrogenation of nitrobenzaldehyde to aminobenzaldehyde with 100%chemoselectivity using H2 gas as the hydrogen source.And we studied the catalytic performance of two Au38 nanoclusters with the same core but different ligands which indicated the significance of protecting ligands to the catalytic performance of nanoclusters.