College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China.
Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , China.
J Am Chem Soc. 2019 Feb 27;141(8):3361-3365. doi: 10.1021/jacs.8b12746. Epub 2019 Feb 18.
S-Nitrosothiols (RSNO) are exogenous and endogenous sources of nitric oxide in biological systems due to facile homolytic cleavage of the S-N bonds. By following the photolytic decomposition of prototypical RSNO (R = Me and Et) in Ne, Ar, and N matrixes (<10 K), elusive caged radical pairs consisting of nitric oxide (NO•) and thiyl radicals (RS•), bridged by O···S and H···N connections, were identified with IR and UV/vis spectroscopy. Upon red-light irradiation, both caged radical pairs (RS•···•ON) vanish and reform RSNO. According to the calculation at the CASPT2(10,8)/cc-pVDZ level (298.15 K), the dissociation energy of MeS•···•ON amounts to 4.7 kcal mol.
S-亚硝基硫醇（RSNO）是生物体系中一氧化氮的外源性和内源性来源，因为 S-N 键易于均裂。通过在 Ne、Ar 和 N 基质中 (<10 K) 跟踪典型 RSNO（R = Me 和 Et）的光解分解，用红外和紫外/可见光谱鉴定了由一氧化氮 (NO•) 和硫自由基 (RS•) 组成的难以捉摸的笼状自由基对，通过 O···S 和 H···N 连接桥接。用红光照射时，两个笼状自由基对 (RS•···•ON) 都消失并重新形成 RSNO。根据 CASPT2(10,8)/cc-pVDZ 水平（298.15 K）的计算，MeS•···•ON 的离解能为 4.7 kcal mol。
