The Photochemistry of Diphenyliodonium Halides: Evidence for Reactions from Solvent-Separated and Tight Ion Pairs

Diphenyliodonium halides exist as tight ion pairs in acetonitrile, and photolysis gives almost exclusively iodobenzene by a homolytic cleavage reaction from a charge transfer excited state, whereas in aqueous acetonitrile the ion pairs are solvent separated and photolysis gives substantial amounts of 2-, 3-, and 4-iodobiphenyls, in addition to iodobenzene, by an initial heterolytic cleavage. © 1991, American Chemical Society. All rights reserved.