Pure metal acetylides and alkynyls

The acetylides M2C2, where M = Cu, Ag or Au, have been long known and they are all explosive. Dry silver acetylide is particularly sensitive to shock. The compounds formed with alkynyl ligands, C=CR, are generally more stable and, in a few cases, form discrete molecules. The known complexes in this class are given in Table 26. The complexes may be 

The complexes (MCsCR), where M = Cu, Ag or Au, all react with ligands such as ammonia and the tertiary phosphines. The ligands serve to depolymerize the complexes by replacement of intermolecular 2r-bonds, forming complexes such as RsPAuC CR (see p. 277). The ammonia complexes readily lose anunonia [262, 263, 267]. The phenylethynyl-gold complexes react more readily with most ligands, suggesting that they 

The relative ease of depolymerization of the alkynyl gold complexes may be associated with the reluctance of gold(I) to raise its co-ordination number above 2 [270]. 

Treatment of phenylacetylene Cu(I) with P-IC6H4NH2 gives Cul and / -NH2C H4=CPh. However, with the ortAo-sUbstituted amine an unusual 

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