Metal Cluster Topology. 2. Gold Clusters.
GEORGIA UNIV ATHENS DEPT OF CHEMISTRY
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Previously developed methods for the treatment of polyhedral boranes, carbonranes, and metal clusters are extended to the treatment of gold clusters, which present a variety of new problems. In most cases gold atoms in such cluster compounds do not employ the usal 9-oribital sp superscript 3 d superscripts spherical bonding orbital manifold. Instead almost all non-tetrahedral gold clusters consist of a center gold atom surrounded by a puckered polygonal belt of peripheral gold atoms generally with one or more additional peripheral gold atoms in distal positions above andor below the belt. The peripheral gold atoms in such clusters use a 7-orbital spd superscripts cylindrical bonding orbital manifold, but their residual two orthogonal antibonding p orbtials can receive electron density from the filled d orbitals of adjacent peripheral gold atoms through backbonding leading to bonding distances between adjacent peripeheral gold atoms. Centered gold clusters can be classified into either spherical or toroidal clusters. The topology of the core bonding in gold clusters mimics the toplogy of the polyhedron formed by the surface atoms. Examples of non-centered gold clusters treated in this paper include the squashed pentagonal bipyramidal Au7PPH37 and the edge-fused bitetrahedral Ph3P4Au6CoCO42 which may be regarded as a perauraethylene in which the six cluster gold atoms correspond to the six atoms of ethylene including a double bond between the two gold atoms corresponding to the two ethylene carbon atoms.
- Inorganic Chemistry
- Organic Chemistry