Gold cluster complexes structure

Slovokhotov, Yu.L. and Struchkov, Yu.T (1984) X-ray crystal structure of a distorted tetrahedral cluster in the salt [(Ph P)4Au4N] BF4 . Geometrical indication of stable electronic configurations in post-transition metal complexes and the magic number 18-e in centred gold clusters. Journal of Organometallic Chemistry, 177, 143-146. 

For each cluster size, the few lowest energy equilibrium isomers with molecular adsorption (MA) and two atoms adsorption (TAA) complexes are represented in Fig 8. Most of these structures are planar or near planar. For 4c, 5b, and 5d, only an O atom is not in the plane. Two atom adsorption leads to major structural changes in the gold cluster, particularly for n>5. For example, in the structures 5a, 6a, and 7a, a gold atom breaks the bonds to other Au atoms to form a highly stable linear O-Au-0 unit which bind each 0 atom to one of the remaining Au atoms. On the other hand, molecular adsorption induces only a modest relaxation in the host cluster, and the O2 molecule is attached on top of a Au atom preferably to the bridge position between two Au atoms. 

The theoretical treatment of bonding and structure of gold clusters has met with considerable success. For the higher gold dusters, the best predictions are that, for a cluster [AutL, 1]"+ in which the peripheral gold atoms define a closed spherical polyhedron, there will be a closed shell electron configuration when 12x + 6 electrons are present. The structures of complexes... 

The synthetic methods used involve reaction of a cluster anion with [AuCIL], elimination of methane between a cluster hydride and [AuMeL] or addition of LAu+ units to metal-metal bonds. The emphasis here will be on structure and reactions of the complexes. Some examples of mixed gold clusters are given in Table 15, where it can be seen that most work has been on derivatives of clusters of iron, ruthenium and osmium. 

The structure of the complexes formed when gold clusters react with oxygen is not always certain, and in particular it is not certain whether the oxygen molecule is dissociated or not.3 Clearly if it is to dissociate, the transfer of charge from the cluster to the molecule must be the first step, but what must happen thereafter if dissociation into atoms is to occur is far from obvious. Some light is cast on this problem by the observation of the vibrational fine structure in the ultraviolet photoelectron spectrum (UPS) of the Au —O2 and Au)C -O2 complexes.8,9 Subsidiary peaks at 179 and 152 meV compare with those found elsewhere for the O2 ion at 80-120 meV and for the 0 ion at 135-150 meV (ImeV = 8.06 cm"1) this suggests... 

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