Photochemistry of Naphthylmethyl Halides. Direct and Sensitized Paths to Homolytic and Heterolytic Carbon-Halogen Bond Cleavage

Article abstract of DOI:10.1021/jo00186a020

Photolysis of the 1-(halomethyl)naphthalenes (X=Cl, Br, I) in methanol and in cyclohexane solution was investigated.Direct and sensitized irradiation leads to carbon-halogen bond cleavage.In methanol solution direct irradiation leads to products of carbon-halogen bond heterolysis, i.e. (methoxymethyl)naphthalene, as well as products derived from bond homolysis.In cyclohexane only homolysis products are observed.The mechanism of the photoreactions was probed by laser spectroscopy, sensitization, and quenching techniques.The results indicate that bond cleavage occurs from excited singlet states but not from the lowest triplet state.Also, an exciplex between sensitizers and the (halomethyl)naphthalene also undergoes carbon-halogen bond cleavage.