Mesityl, gold complexes

The addition of water and methanol to terminal alkynes has also been studied by Laguna et al. by pentafluorophenyl and mesityl gold derivatives. Both acidic and non-acidic conditions led to high activity, even in the presence of as little as 0.5 mol% of catalyst. The use of pentafluorophenyl compounds allowed them to obtain additional spectroscopic information in the stoichiometric reaction of the complex [Au (C6F5)2C1]2 and phenylacetylene, which showed that gold(III) was the active species in the catalytic process. The reaction followed the Markovnikov rule, as shown in the proposed mechanism (Scheme 8.13), delivering the corresponding ketones or diacetal products [96]. 

The first method has been used with haloaryl,1639-1643 urt/m-nitrophenyl,1644 mesityl,255 or ylidegold(I)1645-1648 complexes, which are sufficiently stable to undergo the oxidative addition without cleavage of the gold-carbon bond, an example can be seen in Equation (11) ... 

Apart from the gold(i) system, bis(mesityl)mercury(ii), which also possesses a heavy metal center with strong relativistic effects, has been used for the synthesis of the mixed metal silver(i) aryl complexes, [HgAg2(mes)X2]2 (X = OTf 13a (Figure 7), C104 13b).33 X-ray crystal structure analysis of 13a revealed its hexanuclear nature with the... 

Selected mono- and di(A,A-diorganyl-imidazol-2-ylidene)gold(i) complexes have been investigated for their antibacterial activity. Positive effects against Staphylococcus and Enterococcus bacteria, Escheria coli, and Pseudomona aeruginosa were encountered in particular with the A-substituents being mesityl or benzyl (Equation (51)).278... 

Au((J.-mesityl)]5 (mesityl = 2,4,6-Me3C6H2) as precursor. This Au(I) complex is dissolved first in OA and injected into a heated (300 °C) solution of HDA leading to nanoparticles ranging in size from 10 to 80 nm. Nevertheless, when a more diluted solution of complex [Au( t-mesityl)]5 in OA is injected into a TOPO solution at 190 °C, highly monodisperse gold nanoparticles of 12 lnm are obtained [83] (Scheme 3.11). 

Also, a cationic homotrinuclear organogold(I) complex with mesityl ligands as aryl groups has recently been prepared by reaction of [Au(mes)(dppm)], which contains two potentially bidentate ligands, with bis(tetrahydrothiophene)gold(I)... 

The deviation from the linearity at the gold atom (C-Au-As angle of 166.8(4)°) is only moderate if compared with other complexes with bridging mesityl groups, e.g., [Au5(mes)5].83 It is noteworthy that the mesityl bridge is not symmetrically disposed, in contrast with the usual symmetrical disposition of the aryl ligand in the examples mentioned above. 

Its crystal structure shows a beautiful Au6Ag wheel in which the six gold atoms form a hexagon with the silver atom in the center (Fig. 26). As observed in other aryl bridging complexes,27 83 110 143 145 the planar tris(isopropyl)phenyl groups are nearly perpendicular to the mean plane through the metallic atoms. The Au-C distances, with values between 2.111(7) and 2.200(7) A, are also similar to those in the previously mentioned mesityl complexes. 

Gold(III) is usually separated from Pt and Pd by extraction from 4-8 M hydrochloric acid [18-20] or from H2S04-KBr media [21]. Oxygen-containing solvents, such as DIPE, MIBK, mesityl oxide, or amyl acetate have been used as extractants. Iron(III), which interferes, is masked with phosphoric acid before the extraction of gold. The chloride complex of gold can also be extracted with TOPO in MIBK [20], TBP in toluene or xylene [24]. The anionic... 

These occur more commonly than terminal phenyl ligands, presumably because of the increased M-C contact as indicated (Fig. 3, type B). Copper(I), silver(I) and gold( I) compounds with these bridges are particularly well studied.A number of binary aryl transition metal complexes of the type MjAry have been synthesized. Those with bulky aryls such as mesityl (mes) or perfluorophenyl are the most tractable, the bulk preventing further oligomerization or polymerization. Some... 

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