Photochemistry of N‐aryl and N‐alkyl dibenzothiophene sulfoximines

Abstract

N‐phenyl dibenzothiophene sulfoximine has been demonstrated to produce phenyl nitrene and dibenzothiophene S‐oxide upon irradiation with UV‐A light, and dibenzothiophene S‐oxide upon further irradiation releases triplet atomic oxygen. Thus, N‐phenyl dibenzothiophene sulfoximine exhibits a rare dual‐release capability in its photochemistry. In this work, N‐substituted dibenzothiophene sulfoximine derivatives are irradiated with UV‐A light to compare their photochemistry and quantum yield of dibenzothiophene S‐oxide production with that of N‐phenyl dibenzothiophene sulfoximine. Both N‐aryl and N‐alkyl derivatives of dibenzothiophene sulfoximine are examined to observe their effects on the quantum yield of the photolysis reaction. Adding electron withdrawing N‐aryl substituents is shown to increase the quantum yield of dibenzothiophene S‐oxide production, while adding electron donating N‐aryl substituents is shown to decrease the quantum yield. The quantum yield was slightly lowered or not increased by most N‐alkyl substituents. Furthermore, the quantum yield was not augmented by branching and steric hindrance effects associated with the N‐alkyl substituents. These results suggest that electronic modulation of the sulfoximine bonds affects the observed photolysis reaction.