Controlled Photochemical Release of Nitric Oxide from O 2-Benzyl-Substituted Diazeniumdiolates

• Published in: Journal of the American Chemical Society Vol. 124; no. 33; pp. 9806 - 9811
• Main Authors: Ruane, Patrick H, Bushan, K. Mani, Pavlos, Christopher M, D'S, Raechelle A, Toscano, John P
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 21.08.2002; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; NUCLEOPHILES; COMPLEX-IONS; NO; CONTROLLED BIOLOGICAL RELEASE; ORGANIC-PHOTOCHEMISTRY; CURRENT TRENDS; DESIGN; CHEMISTRY; DONORS; PHOTOLYSIS
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja026900s

An investigation of potential photosensitive protecting groups for diazeniumdiolates (R2NN(O)NO-) has been initiated, and here the effect of meta electron-donating groups on the photochemistry of O 2-benzyl-substituted diazeniumdiolates (R2NN(O)NOCH2Ar) is reported. Photolysis of the parent benzyl derivative (Ar = Ph) results almost exclusively in undesired photochemistrythe formation of nitrosamine and an oxynitrene intermediate with very little, if any, photorelease of the diazeniumdiolate. We have been able to use meta substitution to tune the photochemistry of these benzylic systems. The desired diazeniumdiolate photorelease has been shown to become more substantial with stronger π-donating meta substituents. This effect has been verified by direct observation of the photoreleased diazeniumdiolate with 1H NMR spectroscopy and by NO quantification measurements conducted in high- and low-pH solutions. In addition, the observed rates of NO release are consistent with that expected for normal thermal decomposition of the diazeniumdiolate in aqueous solutions and also show the same pH dependence.