Phenylacetylene radical cation

Photolysis of vinyl halides can induce both heterolysis of the C-X bond, thereby generating vinyl cations, and homolysis giving vinyl radicals. This competition between the two mechanisms was studied for 3-vinyl halides, 1,2,2-triphenylbromoethane (136) and 1-phenyl-2,2-bis(o-methoxyphenyl)-l-bromoethene and /3-styrene. Incursion of the photo-induced SrnI process, through the intermediate vinyl radical, is verified in the presence of reducing nucleophiles, such as the enolate ions of ketones and in part with (EtO)2PO . Incursion of the heterolytic pathway and the intermediacy of the radical cation, occurs in the presence of weak electron-donor anions, such as N02, Ns and Cl . The vinyl cation of /3-styrene gives phenylacetylene via an El-type elimination. 

PET converts phenylacetylene to ot-phenylnaphthalene a 1,4-bifunctional dimer radical cation (96 +) is the key intermediate 1,6-cyclization, followed by a hydrogen or hydride shift generates the final product. ... 

Vibronic Coupling in the Phenyl Radical and Radical Cation of Phenylacetylene... 

Gas phase reaction of phenylacetylene with the distonic peroxyl radical cation 4-PyrOO + in a mass spectrometer leads to the phenylketenyl radical (28) with a rate coefficient k = (2.2 0.6) X 10 cm mol s (Scheme 4.9). " ... 

Anodic cyanation of diphenylamine gave 61% of 4-cyanodiphcnyl-amine (Yoshida and Fueno, 1972) while similar cyanation of di-phenylacetylene gave 60% of 4-cyanodiphenylacetylene (Yoshida and Fueno, 1973) in reactions also believed to involve the cation radical. Use of 2,5-dimethylthiophene (Yoshida et al., 1971) in... 

Silylene 1 is an unusually versatile catalyst for alkene and alkyne polymerization. The list of compounds polymerized by 1 includes ethene, propene, 1-hexene, styrene, dimethylbutadiene, vinylidene chloride, vinyl ethyl ether, methyl methacrylate, and phenylacetylene. The polymerization does not seem to take place by any of the usual mechanisms, anionic, cationic or free-radical. Instead it somewhat resembles coordination polymerization, as observed for Ziegler-Natta type catalysts. Silylene 2 also catalyzes the polymerization of 1-hexene, but the polymerization is 10 to 100 times slower than with 1. 

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