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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.
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How Tryptophan Oxidation Arises by “Dark” Photoreactions from Chemiexcited Triplet Acetone
Abstract Dioxetane intermediates readily decompose to chemiluminescent triplet carbonyls, giving rise to what has been paradoxically called photochemistry in the dark. In this issue ofPhotochemistry and Photobiology, Bechara et al. report on mechanistic advances in such a reaction. With the use of horseradish peroxidase for isobutyraldehyde‐derived triplet acetone, light emission from acetone and singlet oxygen can be quenched. The experiments reveal that the reaction depends on oxygen and the amino acid. The analysis reveals that free tryptophan is a target of this form of “carbonyl stress,” with the efficient formation of mono‐, bi‐ and tricyclic compounds (N‐formylkynurenine, indoline, 1λ2‐indole and 3H‐indoles).
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- Award ID(s):
- 1856765
- PAR ID:
- 10452459
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Photochemistry and Photobiology
- Volume:
- 97
- Issue:
- 2
- ISSN:
- 0031-8655
- Page Range / eLocation ID:
- p. 456-459
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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