Gold heteronuclear clusters metals

Pignolet, L. H. Krogstad, D. A. The Heteronuclear Cluster Chemistry of the Group 11 Metals—Some Recent Advances. In Gold, Progress in Chemistry, Biochemistry and Technology Schmidbaur, H., Ed. Wiley Chichester, U.K., 1999, pp 429-493. 

Summary of Metal-Metal Bond Lengths for High-Nuclearity Gold-Silver Heteronuclear Cluster Compounds... 

A great variety of heteronuclear gold cluster compounds are known. In many of these clusters the AUPR3 moiety behaves like an isolobal proton" " and bridges an edge of a transition metal cluster. While another type of heteronuclear clusters is built up by one central transition metal atom and up to twelve gold atoms, as described in several reviews. " ... 

Heteronuclear compounds containing gold(I) and other metal atoms which present Au -M interactions are well represented in the area of metal carbonyl clusters. The addition of a AuPR3+ or Au2(/u-P-P)2+ fragment to a metal cluster results in the formation of Au—M bonds often with retention of the cluster framework. Several reviews have been reported recently,3153-3155 and so it will not be treated here. Some representative examples are found in Figure 26. 

The most outstanding examples of heteronuclear gold clusters are the series of Au-Ag supraclusters whose metal frameworks are based on vertex-sharing. In the structure of these compounds, the basic building block is the 13-metal atom (Au7Ag6) icosahedra. These high nuclearity clusters have been termed clusters of clusters and they follow a well-defined growth sequence by successive additions of... 

Fig. 1. Examples of the synthesis of heteronuclear gold cluster complexes by the reaction of Au(PPh3)Cl with transition metal anions.

The addition of gold phosphine fragments to transition metal compounds is readily extended to include reactions of heteronuclear gold cluster compounds and has been used to build up clusters of increasing nuclearity, as the following examples illustrate ... 

Electrochemical interconversion of homo- and heteronuclear gold cluster compounds remains an area that has received scant attention, despite the potential for changing the electron count and hence the metal cage geometries of these clusters by electrochemical methods. The electrochemical redox reactions of [Pt(AuPPh3)8]2+ have been studied, using pulse, differential pulse, and cyclic voltammetric techniques (124, 242) and two reversible, one-electron reduction steps have been... 

Much interest has been directed toward the potential catalytic applications of heteronuclear gold cluster compounds. The catalytic chemistry of gold is much less extensive than that of the other noble metals... 

It is possible to synthesize mixed-metal clusters containing Au(PR3) fragments by treating neutral as well as anionic precursors with either [Au(PR3)]+ or a compound that acts as a source of this cation. In many cases, a [Au(PR3)]+ unit is simply added to the cluster precursor to afford a cationic heteronuclear gold cluster (e.g., 59,62-66). Equation (27)... 

The action of hydrogen or oxygen on heteronuclear gold clusters has been used to afford species of higher nuclearity [Eqs. (43)—(45)] (72,83,84). Mixed-metal gold clusters of lower nuclearity have been... 

A homonuclear gold cluster has been used as a precursor to a heteronuclear species in which two gold atoms are bonded to Co(CO)4 fragments [Eq. (55)] (90). Treatment of the cluster salt K[Co3Fe(CO)12] with [Bu"N][AuI2] also affords a mixed-metal cluster containing a Au Co-(CO)4 unit [Eq. (56)] (91). 

Table 2 Some heteronuclear gold-metal clusters...

In the crystalline form the heteronuclear gold cluster compounds are air-stable at ambient temperature and not sensitive to light. Solutions, however, decompose slowly under action of light to form gold metal. 

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