Carbene-gold complexes synthesis

Di(carbene)gold(I) salts, oxidation, 2, 293—294 Dicarbido clusters, with decarutheniums, 6, 1036 Dicarbollide amides, with tantalum, 5, 184 Dicarbollide thorium complexes, synthesis and characterization, 4, 224—225 Dicarbollyl ligands, in nickel complexes, 8, 185 Dicarbonyl complexes arylation with lead triacetates diastereoselectivity, 9, 389 enantioselectivity, 9, 391 mechanisms, 9, 387 reaction examples, 9, 382 indium-mediated allylation, 9, 675 with iridium, 7, 287 reductive cyclization, 10, 529 in Ru and Os half-sandwiches, 6, 508 with Zr—Hf(II), 4, 700... 

The first discussed example was reported by Bertrand and coworkers. By using different iminium salts they reported the coordination of an array of different abnormal NHC ligands, so-called CAAC ligands, to an AuQ fragment. Here, depending on the bulkiness of the free carbene used, the formation of mono- or biscarbene gold complexes is observed [12]. The synthesis of the most known representative of this class of Au(I) complexes in gold catalysis is shown in Scheme 9.3. The unique thermal stabiUty of this NHC-Au(I) complex is discussed in more detail in Section 9.3. 

Reeds, J. R, Whitwood, A. C., Healy, M. R. Fairlamb, 1. J. S. (2013). Synthesis and reactivity of N-heterocyclic carbene gold(I) and gold(III) imidate complexes and their catalytic activity in 1,5-enyne cycloisomerization. Organometallics, 32,3108-3120. 

Gold complexes can also be utilized as catalysts for the synthesis of pyrroles from 1,5-diynes. 2,5-Dimethylpyrrole is synthesized from the reaction of hexa-l,5-diyne and ammonia in the presence of a gold-carbene complex, Au-I [13] ... 

Raubenheimer, H.G., Scott, F., Roos, M. and Otte, R. (1990) The synthesis of gold (1) carbene complexes using 4-methylthiazolyllithium. Journal of the Chemical Society, Chemical Communications, (23), 1722-1723. 

Raubenheimer, H.G., Lindeque, L. and Cronje, S. (1996) Synthesis and characterization of neutral and cationic diamino carbene complexes of gold(I). Journal of Organometallic Chemistry, 511 (1-2), 177-184. 

Desmet, M., Raubenheimer, H.G. and Kruger, G.J. (1997) Synthesis and Characterization of Thienyl Oligomeric, Carbene, and Nitrogen-Donor Complexes of Gold(I). Organometallics, 16(15), 3324-3332. 

Barnard, P.J., Baker, M.V., Bemers-Price, S.J., Skelton, B.W. and White, A.H. (2004) Dinudear gold(I) complexes of bridging bidentate carbene ligands Synthesis, structure and spectroscopic characterisation. Dolton Transactions, 1038-1047. 

Synthesis of silver NHC complexes by the Ag20 method and carbene transfer to gold... 

Imidazolium ligands, in Rh complexes, 7, 126 Imidazolium salts iridium binding, 7, 349 in silver(I) carbene synthesis, 2, 206 Imidazol-2-ylidene carbenes, with tungsten carbonyls, 5, 678 (Imidazol-2-ylidene)gold(I) complexes, preparation, 2, 289 Imidazopyridine, in trinuclear Ru and Os clusters, 6, 727 Imidazo[l,2-a]-pyridines, iodo-substituted, in Grignard reagent preparation, 9, 37—38 Imido alkyl complexes, with tantalum, 5, 118—120 Imido-amido half-sandwich compounds, with tantalum, 5,183 /13-Imido clusters, with trinuclear Ru clusters, 6, 733 Imido complexes with bis-Gp Ti, 4, 579 with monoalkyl Ti(IV), 4, 336 with mono-Gp Ti(IV), 4, 419 with Ru half-sandwiches, 6, 519—520 with tantalum, 5, 110 with titanium(IV) dialkyls, 4, 352 with titanocenes, 4, 566 with tungsten... 

Synthesis of transition metal carbene complexes is achieved by the silver(I) oxide method and subsequent transfer to the next transition metal (in this case gold) (see Figure 3.62). Two different types of silver(l) carbene complexes are realised, the monocarbene and bis-carbene complexes. Transfer of the carbene to a gold(l) centre does not always occur with retention of structure as only the gold(l) monocarbene complexes are observed. 

Similar carbene complexes of silver(l) and gold(l) are observed when catechole is used as the scaffold. Synthesis of the bis-imidazohum salt follows the established protocol with bis-iodoethyl catechole and A-(l-naphthylmethyl)-imidazole as the starting materials [214], Reaction with silver(l) oxide and subsequent carbene transfer to copper(l) iodide yields the corresponding silver(l) and copper(l) carbene complexes. 

The two carbene units can be embedded in a (macro)cyclic ring system known as a cyclophane. A standard procedure for the synthesis of such a system starts with a,a -dibromoxylene and potassium imidazolide [368]. Cychsation can be achieved by reacting the bis-imidazole compound with a second equivalent of a,a -dibromoxylene (see Figure 3.116). The cyclic bis-imidazolium cyclophane can then be reacted with paUadium(II) acetate to form the palladium complex [369,370]. The silver(I) and gold(I) complexes are accessible from the reaction with silver(I) oxide [371] and the usual carbene transfer reaction to gold(I) [372]. 

IV. SYNTHESIS AND PROPERTIES OF ALKENE, ALKYNE, CARBENE AND RELATED COMPLEXES OF GOLD... 

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