H AuCl

Colloidal gold- This can be prepared by the citrate method ( citrate gold ) (see also Chapter 29) using gold chloride and sodium citrate. H(AuCL ). 2% stock solution in water, stable for 1-2 yr at 4°C Dilute to 0 01% in water just before use. Sodium citrate 1% in water, freshly prepared All solutions are made up in double-distilled water of highest purity. Glassware has to be extremely clean (see Note 1). 

The nitrogen-donor complexes of gold(lll) are usually formed by the displacement of chloride in H[AuCLi] by nitrogen-donor ligands. The complex [Au(NH3)4](N03)3, for example, is obtained by bubbling gaseous ammonia into an aqueous solution of H[AuCL(] and ammoninm nitrate. 

H[AuCL,]- 4HjO Tctrachloro- goldsaure s 411,85 leicht Idslich ... 

Finally, intramolecular hydroamination/cyclisation of M-alkenyl ureas was catalysed by the well-defined [AuCl(IPr)] complex (Schane 2.16), in the presence of AgOTf (5 mol%, rt, methanol, 22 h). The cationic Au(lPr)+ is presumably the active species [83]. 

Williams, D.B.G., Traut, T, Kriel, F.H. and van Zyl, W.E. (2007) Bidentate amino-and iminophosphine ligands in mono-and dinuclear gold(I) complexes Synthesis, structures and AuCl displacement by AuC E . Inorganic Chemistry Communications, 10(5), 538-542. 

A similar chiral chlorogold(I) compound [AuCl(CNC6H4C00C6H40C H-MeC6Hi3)j has been described, displaying ferroelectric SmC (152 °C), and SmA (185 °C) mesophases before decomposition occurs at the clearing temperature (285 °C). However, the spontaneous polarization could not be measured with precision due to the inherent conductivity of the compound [12]. 

Tyrpical experimental procedures are as follows for DP method, which is used for the industrial production of gold catalysts. To an aqueous solution of H AuCU, the pH of which is 2-3, an aqueous solution of NaOH is added to adjust the pH at a fix point in the range of 6-10. In neutral or weakly basic solution AuClj" ion is transformed into AuCl (OH)4l ( = 4 0). To this solution support materials are immersed or dispersed. When the pH, concentration, and temperature are carefully adjusted, solid Au(OH)3 precipitate is deposited exclusively on the... 

These short Au-Au contacts may be compared with distances of 2.88 A in metallic gold and 2.60 A in gaseous Au2. The term aurophilicity has been coined by H. Schmidbaur to describe the phenomenon [189,194], The interactions can occur as pairs, squares, linear chains or two-dimensional arrays of gold centres. Examples include the association between dimer units in the dithiocarbamates Au(dtc)2 (Figure 4.16) and the ionic tetrahydrothiophen complexes Au(tht)2 AuXJ (X = halogen), where cations and anions stack with Au—Au 2.97-2.98 A (X = I). The interaction is such that Au(S203)2 pair up, despite their charge, with Au-Au 3.24 A in the sodium salt. Likewise in Aupy AuCl, cations pair up at 3.42 A apart [10, 195]. 

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