The nature of the Sulfur-Metallic bonds (Metal = Ni, Pd and Pt) in doped gold nanoclusters: A density functional approach

Abstract

“Atomically precise gold nanoparticles” that constitute single guest atom doped gold cores besides being protected by ligands, have drawn much attention in the fields of biology, chemistry and physics. To investigate the foundation of organic-metallic interface, metallic alloy- H2S complexes are used to model the core-ligand interactions. In this work, simulation of platinum group doped gold dimers and triangular trimers bonded to H2S, are investigated. To simulate experimental results, features including bond lengths, vibrational frequencies and binding energies were calculated for the dimers of platinum group metals and gold, via DFT. The Au-M dimers have minimum magnetic dipole moments compared to the dimers of two platinum group metals. Among the three platinum group atoms simulated, the relativistic effect prevents Pd from being tightly bonded to other metallic atoms. The “donor-acceptor” model is put forward for the complexes of H2S molecules and dimer/trimers, to explain the interaction of sulfur-metal bonds. The possibility of neighboring metallic atoms affecting the acceptor, Au or platinum group metallic atoms is distinct. A neighboring acceptor may improve the S-M interaction such as S-Ni bond while a neighboring weak donor may reduce the S-M interactions such as S-Pd/Pt bonds. With the isosurface plot of densities of electrons/holes at binding, one can identify that such an interaction involves both electrostatic and covalent features. The complexes having H2S as ligand and cores of the real gold clusters verified the reliability of the donor-acceptor model qualitatively.