Photochemistry and a model for adsorption of some conjugated hydrocarbons

Abstract

Adsorption and photochemical reactions of some phenyl-substituted conjugated molecules have been studied on a commercial Al₂O₃ adsorbent. The heats of adsorption are correlated with the number of conjugated double bonds. Steric effects are discussed. Photocyclization and photooxidation are observed. From this experimental material a model for adapting Hückel MO-theory to the adsorption process is derived. This model, used with 2nd order HMO perturbation theory gives encouraging results on photo-chemical reactivity of adsorbed conjugated molecules.