Ligand Protected Gold Alloy Clusters as Superatoms
Density functional study of the experimentally observed ligand-protected gold alloy clusters reveal the same stabilization mechanism as in ligand protected pure AuN: the delocalized s-electron subsystem of a high symmetry metal core exhibits a shell closing. On the basis of this observation it is predicted that the substitution of a single Au atom in the well-known Au25(SR)18 compound with Pd, Ag, and Cd will produce stable clusters resulting in a method to tune redox properties in such a nanoscale building block. Similar shell closings are shown to stabilize the cores of experimentally known carbonyl protected nickel-gold and nickel-silver clusters. These species can be understood as structurally as well as electronically separated, weakly interacting gold/silver and nickel-carbonyl subsystems.
KeywordsHigh Occupied Molecular Orbital Fermi Energy Lower Unoccupied Molecular Orbital Gold Cluster Delocalized Electron
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- 12.S.A. Ivanov, M.A. Kozee, W.A. Merrill, S. Agarwal, and L.F. Dahl. Cyclo-[Ni(μ2-SPh)2]9 and cyclo-[Ni(μ2-SPh)2]11: new oligomeric types of toroidal nickel(ii) thiolates containing geometrically unprecedented 9- and 11-membered ring systems. J. Chem. Soc., Dalton Trans., pages 4105–4115, 2002. Google Scholar
- 14.A.J.W. Johnson, B. Spencerb, and L.F. Dahl. Synthesis and experimental/theoretical investigation of the high-nuclearity cubic td [au6ni12(co)24]2- cluster, an initial example of a discrete gold-nickel bimetallic-bonded species: comparative analysis of the results of electron-counting methods and the fenske-hall mo model in rationalizing the bonding interactions of its au6ni12 core consisting of five face-fused metal octahedra. Inorg. Chim. Ac., 227:269–283, 1994. CrossRefGoogle Scholar
- 15.M.A. Kozee, J.M. Zhang, and L.F. Dahl. Isostructural T-D [Au16Ni24(CO)(40)](4-) and [Ag16Ni24(CO)(40)](4-) clusters: Stabilization of a microscopic ccp chunk of gold or silver metal. Abstracts of Papers of Am. Chem. Soc., 219:U832–U832, 2000. Google Scholar
- 18.G. Pacchioni, L. Ackermann, and N. Rösch. Chemical bonding in low-, medium- and high-nuclearity nickel carbonyl clusters. Gazz. Chim. Ital., 122:205–214, 1992. Google Scholar
- 26.N.T. Tran, M. Kawano, D.R. Powell, R.K. Hayashi, C.F. Campana, and L.F. Dahl. Isostructural [Au6Pd6(Pd6-xNix)Ni20(CO)44]6- and [Au6Ni32(CO)44]6- Clusters Containing Corresponding Nonstoichiometric Au6Pd6(Pd6-xNix)Ni20 and Stoichiometric Au6Ni32 Nanosized Cores: Substitutional Pd/Ni Crystal Disorder (Coloring Problem) at Only Six Specific Nonadjacent Pseudoequivalent Metal Sites in the 38-Atom Trimetallic Close-Packed Framework. J. Am. Chem. Soc., 121:5945–5952, 1999. CrossRefGoogle Scholar
- 29.M. Walter and M. Moseler. How to observe the oxidation of magnesia supported Pd clusters by scanning tunnelling microscopy. Accepted by Phys. Stat. Solidi, 2009. Google Scholar
- 31.A.J. Whoolery and L.F. Dahl. Synthesis and structural-bonding analysis of the [Au6Ni12(CO)24]2- dianion containing an unprecedented 18-vertex cubic td metal core composed of five face-fused octahedra: the first example of a discrete gold/nickel bimetallic-bonded species. J. Am. Chem. Soc., 113:6683–6685, 1991. CrossRefGoogle Scholar
- 32.J. Zhang and L.F. Dahl. First-known high-nuclearity silver–nickel carbonyl cluster: nanosized [Ag16Ni24(CO)40]4- possessing a new 40-atom cubic Td closed-packed metal-core geometry. J. Chem. Soc., Dalton Trans., page 1269–1274, 2002. Google Scholar