Photolabile 6-nitrobenzo[a]pyrene (6-nitroBaP) released nitric oxide (NO) under visible-light irradiation. The generation of NO and the concomitant formation of the 6-oxyBaP radical were confirmed by ESR. BaP quinones were also detected as further oxidized products of the 6-oxyBaP radical. No such photodegradation was observed with other nitrated BaPs, such as 1-nitroBaP and 3-nitroBaP. DNA-strand breakage, caused by photoexcited 6-nitroBaP, was closely related to its NO-releasing activity. MO calculations of nitrated BaP suggest that the perpendicular conformation of the nitro substituent to the aromatic ring is important for the release of NO with light. These findings may be useful for the development of a new type of NO donor.

中文翻译：

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6-硝基苯并[a]芘光化学生成一氧化氮

光不稳定的 6-硝基苯并 [a] 芘 (6-nitroBaP) 在可见光照射下释放一氧化氮 (NO)。通过 ESR 证实了 NO 的产生和 6-oxyBaP 自由基的伴随形成。BaP 醌也被检测为 6-oxyBaP 自由基的进一步氧化产物。对于其他硝化 BaP，例如 1-nitroBaP 和 3-nitroBaP，未观察到这种光降解。由光激发的 6-nitroBaP 引起的 DNA 链断裂与其 NO 释放活性密切相关。硝化 BaP 的 MO 计算表明，硝基取代基与芳环的垂直构象对于用光释放 NO 很重要。这些发现可能有助于开发新型 NO 供体。