The Constitution of Pirylene: Electron Diffraction Investigation

Abstract

In connection with the studies described in the foregoing article' we have carried out an electron diffraction investigation of the C_5H_6 hydrocarbon pirylene with the object of determining its structural formula. Our results show that pirylene does not contain a three or four-membered ring as suggested by von Braun and Teuffert but that it is methylvinylacetylene, CH_3-C≡C--CH=CH_2. This identification is substantiated by the agreement of the physical properties of pirylene with those reported for methylvinylacetylene and by chemical evidence. We wish to express our thanks to Dr. E. R. Buchman for suggesting the problem and to him and his collaborators for providing the sample of pirylene used in the investigation.