Alkynylsilver complexes

The insoluble alkynylsilver complexes are regarded as coordination polymers (RC=CAg)co with cross-linking between the metal atoms and the ethynyls of adjacent RC=CAg units. Donor molecules (L) such as tertiary amines, phosphines and arsines can partly break down the polymeric structure. Thus the reactions of PhC=CAg with isopropylamine, trimethyl-, triethyl- or triphenylphosphine and triethylarsine yield the 1 1 complexes of the composition [(L)AgC=CR]49-51. 

Although reports on silver(i) cr-alkynyl complexes have appeared for more than a century, the number of examples was still very limited prior to the past decade, and many of them were referred to as insoluble homoleptic polymeric [Ag(C=CR)]oo. Molecular alkynylsilver(i) complexes were often heteroleptic in nature and were achieved commonly through the stabilization by an extra coordination with strong cr-donor ligands such as amines, phosphines, and arsines. 

For mechanistic investigations on Pd/Ag-catalyzed enyne or arylyne synthesis, Pale et al. mixed various alkynylsilvers with vinyl Inflates or aryl iodides in the presence of palladium salts or complexes (Scheme 10.66).105 This reaction clearly demonstrated that organosilvers can be transmetalated to organopalladium species, even if no halide was present, as demonstrated when starting from vinyl triflates. 

Complex anionic silver acetylides, K[Ag(CCR)2] (R = H, Me, Ph), are known and are prepared from the appropriate alkynylsilver and the potassium acetylide in a polar solvent. They are colorless crystalline solids that are sensitive to light and that decompose in solution. They apparently are not explosive. 

Reaction of alkynes with AgNOj or AgClO 4. in alcohols or HjO in the presence of NH3 results similarly in alkynylsilver(I) compounds quantitatively. When xs AgNOj is used and the reaction is performed in neutral solution, complex formation between alkynylsilver and AgNOs takes place. The ratio AgNOj AgC=CR in these complexes depends on the AgNOj concentration during the reaction . 

The 1 1 complexes of alkynylsilver compounds with tertiary phosphines build oligomeric or polymeric structures in which alternating Ag(C=CR)2 units jr-donate to... 

Gascade procedures and Sonogashira conditions have been used to obtain dendrimer building blocks like 27-30 and metallodendrimers. Luminescent heterodimetallic rhenium-alkynylpalladium complexes 31 and 32 were obtained through the use of m situ prepared alkynylsilver(i) species that reacted with common palladium precursors with GuGl/Et3N as the co-catalyst. Gomplex 31 was authenticated by an X-ray crystal structure. " ... 

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