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Abstract N‐phenyl dibenzothiophene sulfoximine has been demonstrated to produce phenyl nitrene and dibenzothiopheneS‐oxide upon irradiation with UV‐A light, and dibenzothiopheneS‐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 dibenzothiopheneS‐oxide production with that ofN‐phenyl dibenzothiophene sulfoximine. BothN‐aryl andN‐alkyl derivatives of dibenzothiophene sulfoximine are examined to observe their effects on the quantum yield of the photolysis reaction. Adding electron withdrawingN‐aryl substituents is shown to increase the quantum yield of dibenzothiopheneS‐oxide production, while adding electron donatingN‐aryl substituents is shown to decrease the quantum yield. The quantum yield was slightly lowered or not increased by mostN‐alkyl substituents. Furthermore, the quantum yield was not augmented by branching and steric hindrance effects associated with theN‐alkyl substituents. These results suggest that electronic modulation of the sulfoximine bonds affects the observed photolysis reaction. 

Abstract Photodeoxygenation of dibenzothiopheneS‐oxide (DBTO) is believed to produce ground‐state atomic oxygen [O(³P)] in solution. Compared with other reactive oxygen species (ROS), O(³P) is a unique oxidant as it is potent and selective. Derivatives of DBTO have been used as O(³P)‐precursors to oxidize variety of molecules, including plasmid DNA, proteins, lipids, thiols, and other small organic molecules. Unfortunately, the photodeoxygenation of DBTO requires ultraviolet irradiation, which is not an ideal wavelength range for biological systems, and has a low quantum yield of approximately 0.003. In this work, benzo[b]naphtho[1,2‐d]selenopheneSe‐oxide, benzo[b]naphtho[2,1‐d]selenopheneSe‐oxide, dinaphtho[2,3‐b:2’,3’‐d]selenopheneSe‐oxide, and perylo[1,12‐b,c,d]selenopheneSe‐oxide were synthesized, and their ability to utilize visible light for generating O(³P) was interrogated. Benzo[b]naphtho[1,2‐d]selenopheneSe‐oxide produces O(³P) upon irradiation centered at 420 nm. Additionally, benzo[b]naphtho[1,2‐d]selenopheneSe‐oxide, benzo[b]naphtho[2,1‐d]selenopheneSe‐oxide, and dinaphtho[2,3‐b:2’,3’‐d]selenopheneSe‐oxide produce O(³P) when irradiated with UVA light and have quantum yields of photodeoxygenation ranging from 0.009 to 0.33. This work increases the utility of photodeoxygenation by extending the range of wavelengths that can be used to generate O(³P) in solution.