物理化学学报Issue(11)：2134-2141,8.DOI:10.3866/PKU.WHXB201409161
二氟沙星在中性水溶液中的光化学性质
Primary Photochemical Properties of Difloxacin in Neutral Aqueous Solution
摘要
Abstract
The photochemical properties of difloxacin (DFX) were investigated in neutral aqueous solution. DFX aqueous solution showed intense absorption with one peak at 273 nm (molar absorption coefficientε=33000 dm3∙mol-1∙cm-1) and two other peaks at 323 and 335 nm (ε=15500 dm3∙mol-1∙cm-1) with the same molar absorption coefficient. Both the absorption and emission properties of DFX were pH-dependent. The acid dissociation constant (pKa) for the protonation equilibria of the ground state (5.9 and 9.8) were determined spectroscopical y. DFX fluoresces weakly, and its maximum quantum yield for fluorescence emission was 0.06 at pH 3. Laser flash photolysis and pulse radiolysis studies were carried out to characterize the transient species of DFX aqueous solution. Triplet-triplet absorption reached a maximum at 620 nm with a molar absorption coefficient of 7900 dm3∙mol-1∙cm-1. The energy transfer method was used to estimate the triplet energy of DFX, which was 263.5 kJ∙mol-1. The quantum yield of triplet formation was determined to be 0.21. Furthermore, DFX showed monophotonic photoionization with a quantum yield of 0.02. Pulse radiolysis indicated that DFX could react with e-aq and∙OH, and the bimolecular rate constants for these reactions were 1.72×1010 and 1.0×1010 dm3∙mol-1∙s-1, respectively. It is expected that this research may be helpful in determining the phototoxicity mechanism of DFX.关键词
光化学性质/激光光解/脉冲辐解/二氟沙星/激发态Key words
Photochemical property/Laser flash photolysis/Pulse radiolysis/Difloxacin/Excited state分类
化学化工引用本文复制引用
李海霞,周保昌,刘艳成,唐睿智,张鹏,李景烨,王文锋..二氟沙星在中性水溶液中的光化学性质[J].物理化学学报,2014,(11):2134-2141,8.基金项目
The project was supported by the National Natural Science Foundation of China (21173252).国家自然科学基金(21173252)资助项目 （21173252）
