Ag-15(N-triphos)(4)(Cl-4)(NO3)(3): a stable Ag-P superatom with eight electrons (N-triphos = tris((diphenylphosphino)methyl)amine

摘要

A first and stable Ag-P superatom nanocluster [Ag-15(N-triphos)(4)(CL4)](NO3)(3) (1) has been successfully synthesized and characterized. X-ray analysis shows that this Ag-15 cluster has a hexacapped body-centered cubic (bcc) framework which is consolidated by four tripodal N-triphos ligands. The identity of 1 is confirmed by high resolution ESI-MS. Cluster 1 has an electronic and geometric shell closure structure with 8 free electrons, matching the stability idea of superatom theory for a nanocluster. DFT calculation of this Ag-15 cluster reveals the superatom feature with a 1S(2)1P(6) configuration. The chelation of multidentate phosphines enhances the stability of this Ag-15 cluster. The Ag center dot center dot center dot Ag distances between the centered and the vertical Ag atoms of this bcc (Ag@Ag-8 ) are in the range of 2.57-2.71 angstrom, and the distances between the face-capped and the vertical silver atoms are in the range of 2.84-2.92 angstrom , showing strong Ag center dot center dot center dot Ag interactions within this cluster core. This superatom complex exhibits a relatively high thermal and photolytic stability.