Alkyne Addition to the Transition Metal Salts and Complexes

Reactions of Cu(I) and Ag(I) salts with 1-alkynes usually lead to formation of acetylide complexes which possess both a metal-acetylide and n metal-acetylene bonds. However, under particular conditions such as alcohol or acidic aqueous solutions. 

Solid state copper(I) chloride reacts also with gaseous acetylene or RC = CR to give complexes of the following composition  

Acetylene complexes may also be obtained from salts containing metals in their higher oxidation states. In such cases, the alkyne plays the role of a reducing agent. 

Metal alkyne compounds are also generally formed as a result of acetylene addition to unsaturated coordination complexes, most commonly to 16e compounds. An example is provided by the formation of pentacoordinate Ir(I) alkyne complexes  

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