Pentafluorophenylgold I Derivatives

The first synthesized pentafluorophenylgold(I) complex was [Au(C6F5)PPh3[ obtained by the reaction of [AuClPPhs] and CgFsMgBr [30-32]. This complex was at the same time the first characterized [33] by X-ray studies showing the common nearly linear distribution of the phosphorous and the ipso carbon atom (178(1)°). Nowadays, there are many methods of obtaining this complex, in many cases as a by-product of some reaction and, in other cases, its formation is the driving force of the reaction. We will see examples of both in this chapter. 

The first complex described with an Au—S [39] bond was [Au(C6F5)(tht)j (tht = tetrahydrothiophene) that was synthesized by reacting [AuCl(tht)] with LiCfiFs. The complex can also be prepared by the reaction of [Au(tht)2]C104 with NBu4[Au (C ,F5)2] [35]. 

This Au(I) complex was tested as co-catalyst in palladium-catalyzed alkynylation reactions but this derivative is much less active than the analogous chloride complex [AuCl(tht)] needing over twice as long to fully convert the starting material [42]. 

1 Neutral Pentafluorophenylgold(l) Derivatives with C-Donor Ligands 

The reaction of methylene bis(dialkyldithiocarbamates) with [Au(C6F5)(tht)j leads to the complexes [ Au(C6F5) 2 CH2(S2CNR2)2 ] [43] (R = Me, Et, n-Bu, Bz). The NMR resonances of the bridging methylene groups in the complexes are observed at lower field than that in the free ligand and some modification of the C=S stretching is observed. 

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Two different strategies can be used for the synthesis of di- and trinuclear pentafluorophenylgold(I) derivatives using [Au(QF5)(tht)] as one of the starting materials. 

All known pentafluorophenylgold(I) iron complexes are derivatives of ferrocene. In fact, they are obtained mainly by reaction of [Au(CgF5) (tht)] with modified ferrocenes... 

The most general method of preparing pentafluorophenylgold(III) derivatives is oxidative addition with the appropriate oxidant to the gold(I) complex. The choice of... 

An important number of polynuclear pentafluorophenylgold(III) and mixed gold (I)-gold(III) derivatives have been described with the diphosphine 1,2-diphosphmo-benzene, which contains four hydrogen atoms that can be removed and substituted by a metal atom (Scheme 3.5) [220]. 

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