Unsupported gold

Crespo, O., Laguna, A., Fernandez, E.J., Lopez-de-Luzuriaga, J.M., Mendia, A., Monge, M., Olmos, E. and Jones, P.G. (1998) [Tl(OPPh3)2][Au(C6F5)2] the first extended unsupported gold-thaDium linear chain. Chemical Communications, (20), 2233-2234. 

Tubes—Is Unsupported Gold Catalytically Active ChemPhysChem, 8, 1911-1913. 

The electron rich aurate [Au(C6F5)2] also reacts with thallium salts in the presence of a ligand to give extended unsupported gold-thallium linear chain derivatives. The first example... 

Compound [ Au(PTA)3 2 Au2(iso-MNT) 2] (Figure 2.51a) is an example of unsupported gold-gold interactions. It has been prepared from the water soluble [AuCl (PTA)3] and K2[iso-MNT] [286] and its crystal structure consists on a nonlinear tetranudear chain. A cydic disposition of the four gold atoms is found in [Au4(S2CMe)4] (Figure 2.51b) [287]. 

Based on the previously described silver complex [Au2Ag2(Q)f,s)4(MeCN)2 , the same reaction with CuCl in acetonitrile but with addition of an equivalent of pyrimidine leads to the polymeric [CuAu(C6F5)2(MeCN)((J.2-C4H4N2)]n [66]. The polymerization of this complex is produced by covalent copper-pyrimidine bonds. The environment of the copper centers also comprises unsupported gold-copper interactions of 2.8216(6) A and one molecule of acetonitrile, leading to a distorted tetrahedral arrangement (see Figure 6.26). 

Figure 3.1 Four important conditions for catalysis by gold (metal-oxide junction, water, OH- and size of the Au particles or tubes). The figure by each circle is the diameter (nm) of the gold particles or tubes. Gold turns out to be catalytically very active, provided that at least two of the four conditions are fulfilled. For example, in CO oxidation at room temperature even unsupported gold is active in the presence of alkaline (OH-) water (H20).

Reactions between basic gold(I) complexes and acid thalliumff) salts, which give rise to supramolecular networks formed via acid-base stacking containing unsupported gold-thallium interactions. 

The next three sections provide brief descriptions of ways of making clusters and small unsupported gold particles. Their physical and catalytic properties... 

As in the case of CO oxidation [14], the liquid phase oxidation of alcohols and aldehydes is quite sensitive to the size of the gold particles and this behavior was observed since the early tests [9]. A great contribution to this study was the discovery of the catalytic activity of unsupported gold particles. Starting from experimental evidence, it became possible to derive the simple model discussed in Section 13.3.2,... 

The presence of an oxide support, and therefore of a gold-support interface, is of definihve importance to get achve catalysts. Unsupported gold particles are poorly... 

Heterobimetallic Complexes of the Group 11 Metals 1421 Figure 11.31 An unsupported gold(ll) trifluoromethyl complex. 

Tyrra, Mathur, and coworkers [167] report the photoreaction of a silver(I) his(trifluoromethyl) aurate(I) salt that leads to an unsupported gold(II) trifluoromethyl ... 

The support can participate at the interface. The interface sites can have chemical properties that are different from those of both phases. This may be one of the reasons gold particles supported on TiO have catalytic properties different from those of bulk (unsupported) gold. 

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