|
|||||
|
|
Possible singlet oxygen generation from the photolysis of indigo dyes in methanol, DMSO, water, and ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate |
|
| Authors: | Naveen Gandra Onica Le Gendre David Aebisher KN Houk Ruomei Gao |
| Institution: | a Department of Chemistry, Jackson State University, Jackson, MS 39217, USA b Department of Chemistry, Graduate Center and The City University of New York (CUNY), Brooklyn College, Brooklyn, NY 11210, USA c Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD 21250, USA d Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA |
| Abstract: | We suggest that singlet molecular oxygen 1O2 (1Δg)] is formed upon irradiation of indigo 1 in air or O2-saturated DMSO and DMSO (0.5% H2SO4)] and indigo carmine 2 in air or O2-saturated CH3OH, D2O, and 1-butyl-3-methylimidazolium tetrafluoroborate (BmIm-BF4)]. The quantum yield for production of 1O2 is estimated to be 0.6 for 1 and 0.3-0.5 for 2. The rates of reaction of 1O2 with 1 and 2 were determined by monitoring the emission of 1O2 at 1270 nm over time. Low molar absorptivities (at 532 nm) and rapid physical quenching caused by 1 and 2 limit their utility as 1O2 photosensitizers in solution. Compounds 1 and 2 degrade slowly during the photolysis due to a self-sensitized (type I or II) photooxidation reaction. Oxidative cleavage of 1 by singlet oxygen and superoxide, and 2 by superoxide has been noted before (Kuramoto, N.; Kitao, T. J. Soc. Dyers Color. 1979, 95, 257-261; Kettle, A. J.; Clark, B. M.; Winterbourn, C. C. J. Biol. Chem. 2004, 279, 18521-18525). |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ | |