Gold complexes ligands

A structurally characterized gold complex with a C5HPh4 ligand Au(r C5HPh4)(PPh3) (46a) was reported [66], An unusual trinuclear cluster 46b derived therefrom was also characterized by X-ray structural analysis. 

A related dinuclear species 77, recently described, constitutes the first dinuclear gold(I) complex with heterobridged phosphor-1,1 -dithiolato moieties and bis(ylide) bridging ligands [ 102]. It is obtained by reaction between [ AuS2PPh2] and the diylide gold complex 74 (R=Me). No intermolecular Au-Au interaction is observed in 77 but the oxidative addition of chlorine to the product leads to a new complex 78 in which a single bond is formed between the two Au(II) centers (Scheme 26). 

Figure 1.2 Amidine ligands used in the synthesis of terta-, tri-, and dinuclear gold complexes.

Bardaji, M., Laguna, A., Perez, M.R. and Jones, P.G. (2002) Unexpected ring-opening reaction to a new cyanamide-fhiolate ligand stabilized as a dinuclear gold complex. Organometallics, 21, 1877. 

In addition to the simple reaction of a poly dentate ligand with [Au(C6F5)(tht)] the other versatile synthesis of di- and trinudear derivatives is the use of gold complexes as ligands. 

Polynuclear Au(I) pentafluorophenyl complexes can also be obtained by reaction of [AulCfiFsjItht)] with polydentate ligands or with gold complexes that still have different coordination sites or can be created before the subsequent reaction. The ligands or complexes that react with [Au(C6F5)(tht)] and the complexes obtained are listed in Table 3.6. 

Uson, R., Laguna, A. and Villacampa, M.D. (1984) Mono and binuclear gold complexes with diamine and carbene ligands. Inorganica Chimica Acta, 81(1), 25-31. 

Hrusak, J., Hertwig, R.H., Schroder, D.H., Schwerdtfeger, P., Koch, W. and Schwarz, H. (1995) Relativistic Effects in Cationic Gold(I)-Ligand Complexes A Comparative Study of Ah Initio Pseudopotential and Density Frmctional Methods. Organometallics, 14,1284—1291. 

Seidel, S. and Seppelt, K. (2000) Xenon as a Complex Ligand The Tetra Xenono Gold(II) Cation in AuXe4 + (Sb2Fn )2. Science, 290, 117-118. 

Excluding gold complexes that caimot transverse the membrane such as AuSTm, intracellular gold concentrations must approach equilibrium with extracellular gold concentrations if active transport is not at work. The balance of gold between the environment of a cell and within the cell will depend on the ligands available. 

Lateral monofluorination of the p-alkoxyphenyl isocyanide system [XAu (CNC6H40C H2 +i)] (X = C1, Br, I), in ortho-(3-F) (6a) and meta-(2-F) (6b) positions relative to the alkoxy chain was also studied [18]. None of the free fluorinated ligands is a LC, but their gold complexes display mesomorphic properties. This is a typical case of a promesogenic ligand which yields a mesogen upon coordination to a metal. 

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