Polyynes, synthesis, acetylene

A good approach for the synthesis of infinite polyyne or cumulene may be the polymerization of a monomeric compound. Hay [10] in 1969, Matsuda et al. [11] in 1984 and Kudryavtsev [12,13] have shown the possibility of synthesizing carbyne by oxidative dehydropolycondensation of acetylene. They found that carbyne powder was obtained by passing acetylene through an aqueous ammoniacal solution of a Cu(II) salt. The carbyne obtained by this method was nano-crystalline but it might be unstable under an oxygen atmosphere. Most recent re-investigation of this synthetic route by Cataldo and Capitani [14], who used solid state C-NMR, infrared and Raman spectroscopy and other analytical techniques, has revealed that the carbonaceous matter obtained is indeed rich in carbynoid structures but also consists of sp -and sp -carbon atoms. 

Synthesis of Polyynes. Conjugated diyne and polyyne units, which exhibit unusual electrochemical, optical, and structural properties, can be efficiently constructed from 1-haloalkynes via homologation by one acetylene unit with TIPS-acetylene through a transition metal-catalyzed cross-coupling reaction, 2 which allows an access to a new class of polyyne framework. 

The final major application of Glaser-Type coupling of terminal dialkynes is the synthesis of polymeric acetylenes.Following the seminal work of Hay ° and others,polymeric coupling of terminal bis-acetylenes has led to a myriad of polymeric acetylenes. Some pioneering examples are 85 (polymerization of w-diethynylbenzene), ° 86 (polymerization of 1,8-nonadiyne), a-carbyne (polyyne) (87) (polymerization of dicopper... 

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