Tetranuclear gold clusters

Table 1.2 Average Au Au distances (A) and Au Au Au angles (°) of tetranuclear gold(l) amidinate and related clusters.

Formation of Mixed-Ligand Tetranuclear Gold(l) Nitrogen Clusters... 

Density functional theory (D FT) modeling calculations show that a dinuclear gold(I) amidinate complex is less stable than the tetranuclear gold(I) amidinate cluster, [Au4(HNC(H)NH)4]. However, replacing C by Si in the backbone reduces ring strain and makes the energies similar. Figures 1.21 and 1.22 [39]. 

The tetranuclear derivatives are classified as derivatives of the three principal carbonyl cluster units observed, H4M4(CO)12, H2M4(CO)13, and MjCCOlxs, with a final group involving bonding to platinum or gold. 

Taking advantage of both aurophilicity and argentophilicity, tetranuclear mixed-metal complexes which contain pairs of Au and Ag atoms have been prepared, as shown in Fig. 19.6.3. In the preparation of mixed gold/silver polynuclear complexes, aurophilicity and argentophilicity have been utilized to promote cluster formation. Figure 19.6.4 shows the cores of several mixed gold-silver clusters. 

Gold. Evaporation of metallic gold into an ethanolic solution of dppm and ammonium nitrate results in formation of a tetranuclear cluster that incorporates a linear Au unit bonded to the carbon of a deprotonated dppm (20). ... 

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