Factors affecting the photoaddition reactions of diphenylmethane

Abstract

Diphenylmethane does not undergo photoaddition reactions which require initial excitation of the S₀→S₁ transition of the arene. Reaction does, however, occur either by excitation within the charge-transfer absorption band of a ground-state complex between diphenylmethane and an addend (maleic anhydride) or by attack of a photoexcited addend (N-ethylmaleimide) onto the arene. It is considered that a mechanism for energy dissipation from S₁ diphenylmethane involves through-bond interaction between the phenyl groups.