Employing first-principles methods, based on density functional theory, we report the ground state geometric and electronic structures of gold clusters doped with platinum group atoms, AuNM (N=1–7, M=Ni, Pd, Pt). The stability and electronic properties of Ni-doped gold clusters are similar to that of pure gold clusters with an enhancement of bond strength. Due to the strong d-d or s-d interplay between impurities and gold atoms originating in the relativistic effects and unique properties of dopant delocalized s-electrons in Pd- and Pt-doped gold clusters, the dopant atoms markedly change the geometric and electronic properties of gold clusters, and stronger bond energies are found in Pt-doped clusters. The Mulliken populations analysis of impurities and detailed decompositions of bond energies as well as a variety of density of states of the most stable dopant gold clusters are given to understand the different effects of individual dopant atom on bonding and electronic properties of dopant gold clusters. From the electronic properties of dopant gold clusters, the different chemical reactivity toward O2, CO, or NO molecule is predicted in transition metal-doped gold clusters compared to pure gold clusters.

The carbon–carbon triple bond (–C≡C–) is an elementary constituent for the construction of conjugated molecular wires and carbon allotropes such as carbyne and graphyne. Here we describe a general approach to in situ synthesize –C≡C– bond on Cu(111) surface via homo-coupling of the trichloromethyl groups, enabling the fabrication of individual and arrays of poly(p-phenylene ethynylene) molecular wires. Scanning tunneling spectroscopy reveals a delocalized electronic state extending along these molecular wires, whose structure is unraveled by atomically resolved images of scanning tunneling microscopy and noncontact atomic force microscopy. Combined with density functional theory calculations, we identify the intermediates formed in the sequential dechlorination process, including surface-bound benzyl, carbene, and carbyne radicals. Our method overcomes the limitation of previous on-surface syntheses of –C≡C– incorporated systems, which require the precursors containing alkyne group; it therefore allows for a more flexible design and fabrication of molecular architectures with tailored properties.