Photochemistry of Benzene Isomers. 1. Fulvene and 3,4-Dimethylenecyclobutene

Article abstract of DOI:10.1021/j150619a007

The photochemical behavior of the benzene isomer fulvene is investigated at various excitation wavelengths.The only observable photoproduct is benzene, produced in high quantum yield below about 275-nm excitation.The quantum yield is dependent upon excitation wavelength indicating the photoisomerization requires vibrational activation.Quenching by various added gases is efficient and suggests that the photochemistry does not invove triplet-state or free-radical mechanisms.Another isomer, 3,4-dimethylenecyclobutene, also shows photochemical behavior upon excitation at 240 and 215 nm to produce a polymeric material.