RESUMO
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 AgAg 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 AgAg interactions within this cluster core. This superatom complex exhibits a relatively high thermal and photolytic stability.
RESUMO
Density functional theory (DFT) and ab initio method have been employed to optimize the molecular geometry of (1,2-micro2-H) (1, 2-micro2-L) Os3 (CO)10 (L: Cl, Br, I) at B3LYP/CEP-4G, B3LYP/LanL2DZ, RHF/CEP-4G and RHF/LanL2DZ levels, respectively. By using ab initio method, the authors have optimized the molecular geometry of (1,2-t12 -L)2 Os3 (CO)20 (L: H, Cl, Br, I). The calculations showed that the charge was translated from Os(CO)3 to Os(CO)4. Harmonic vibrational analysis was performed at the RHF/CEP-4G levels, and according to the frequencies and intensities of the equilibrium structure obtained by using ab initio method, the IR spectra of structure have been simulated. The calculated results were compared with each other and with available experimental data, and were discussed in detail.