To enhance the versatility of organic azides in organic synthesis, a better understanding of their photochemistry is required. Herein, the photoreactivity of azidoisoxazole 1 was characterized in cryogenic matrices with IR and UV-Vis absorption spectroscopy. The irradiation (λ = 254 nm) of azidoisoxazole 1 in an argon matrix at 13 K and in glassy 2-methyltetrahydrofuran (mTHF) at 77 K yielded nitrosoalkene 3. Density functional theory (DFT) and complete active space self-consistent field (CASSCF) calculations were used to aid the characterization of nitrosoalkene 3 and to support the proposed mechanism for its formation. It is likely that nitrosoalkene 3 is formed from the singlet excited state of azidoisoxazole 1 via a concerted mechanism or from cleavage of an intermediate singlet nitrene that does not undergo efficient intersystem crossing to its triplet configuration.

中文翻译：

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5-叠氮基-3-苯基异恶唑在低温下的光解：亚硝基烯烃的形成和直接检测

为了提高有机叠氮化物在有机合成中的多功能性，需要更好地了解它们的光化学。在此，叠氮异恶唑 1 的光反应性在低温基质中通过 IR 和 UV-Vis 吸收光谱进行表征。叠氮异恶唑 1 在 13 K 的氩基质和 77 K 的玻璃状 2-甲基四氢呋喃 (mTHF) 中的辐照 (λ = 254 nm) 产生亚硝基烯烃 3。 密度泛函理论 (DFT) 和完全活性空间自洽场 (CASSCF) ) 计算用于帮助表征亚硝基烯烃 3 并支持其形成的拟议机制。