Organogold compounds carbenes

Carbenes form stable complexes with many metals in the periodic table of the elements, and gold is no exception. In fact, the chemistry of this class of organogold compounds for some time has been one of the fastest growing subdisciplines. While the corresponding chapters were still short in previous accounts,1 2 the inventory for this review is now particularly rich and diverse.230 As for other classes of carbene complexes, this upsurge is based on expectations for potential applications in various fields such as NLO materials, liquid crystalline phases, and catalysis. Where applicable, this is indicated for each of the entries in this chapter. 

Organogold carbene compounds [Au(carbene)(CN) j iR ] can be obtained from com-plexed cyanides [Au(CN)m(C6F5) ] (n = 1 or 3, m = 1 and n = m = 2) by sequential alkylation (to form isocyanide complexes) and nucleophilic attack of amine" . Gold(III) diisocyanides [Au(CNR)2(CgF5)2]+ (R = Ph or p-tolyl), which can also be obtained by isocyanide substitution of ether in [Au(C6F5)2(OEt2)2] > react with hydrazobenzene NH(Ph)NHPh and hydrazine or phenyUiydrazine according to the reactions in Scheme 32 to furnish cyclic bis(carbene) and cyclic carbene-imidoyl compounds . ... 

The use of diazo compounds has also attracted some attention. NHC-Au catalysts, and especially those bearing the IPr and IMes ligands, mediated the decomposition of diazo species, leading to organogold carbenes, which could be observed in the gas phase. Once formed, the NHC-Au carbene could participate in a variety of reactions that include insertions into X-H bonds (X = C, N, Buchner reactions, ° and olefin cyclopropanation. ... 

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