Solution Photochemistry of Azulene

Article abstract of DOI:10.1021/jo00081a024

Photochemical reactivity has been observed in solution-phase azulene.Experiments are described which confirm photoinduced deuteration, chlorination, and polymerization.The threshold for the observed chemistry is at the origin of S₂ which is at 27956 +/- 8 cm^-1 (357.7 +/- 0.1 nm) in chloroform.Only one photon is required to induce the observed chlorine substitution reactions.Although no naphthalene is formed, this chemical channel appears to be the equivalent of a thermal reaction, with the substitutions taking place at the two equivalent positions on the small ring of azulene.The mechanism of these reactions is bimolecular in nature.Chlorination provides a complex mixture of products in most cases; however, deuteration proceeds cleanly giving only 1,3-d2-azulene.