[Ag15(N-triphos)4(Cl4)](NO3)3: a stable Ag–P superatom with eight electrons (N-triphos = tris((diphenylphosphino)methyl)amine)†
Abstract
A first and stable Ag–P superatom nanocluster [Ag15(N-triphos)4(Cl4)](NO3)3 (1) has been successfully synthesized and characterized. X-ray analysis shows that this Ag15 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 Ag15 cluster reveals the superatom feature with a 1S21P6 configuration. The chelation of multidentate phosphines enhances the stability of this Ag15 cluster. The Ag⋯Ag distances between the centered and the vertical Ag atoms of this bcc (Ag@Ag8) are in the range of 2.57–2.71 Å, and the distances between the face-capped and the vertical silver atoms are in the range of 2.84–2.92 Å, showing strong Ag⋯Ag interactions within this cluster core. This superatom complex exhibits a relatively high thermal and photolytic stability.