1714-20-1Relevant articles and documents
Probing mechanisms of aryl-aryl bond cleavages under flash vacuum pyrolysis conditions
Jackson, Edward A.,Xue, Xiang,Cho, Hee Yeon,Scott, Lawrence T.
, p. 1279 - 1287 (2014)
Several biaryls have been subjected to flash vacuum pyrolysis (FVP) at 1100°C and 0.8-0.9hPa. Product compositions are reported for the FVP of 9-phenylanthracene (1), 2-bromobiphenyl (5), biphenyl (8), 1,10- diphenylanthracene (12), 9-(2-naphthyl)anthracene (17), and 9,9′- bianthracenyl (20). The experimental results have been used to evaluate four possible mechanistic pathways for the cleavage of aryl-aryl bonds under these conditions: (1) the 'explosion' of substituted phenyl radicals; (2) hydrogen atom attachment to an ipso-carbon atom of the biaryl followed by C-C bond cleavage; (3) direct homolysis; and (4) loss of a fragment as an aryne. None of these mechanisms by itself successfully accommodates all of the experimental facts. The data suggest that aryl-aryl bond cleavages under FVP conditions involve at least two different mechanistic pathways and that the relative contributions of the competing pathways probably vary from one biaryl to the next.