Photophysical properties of gatifloxacin in aqueous solution by laser flash photolysis and pulse radiolysis |
| |
Authors: | Haixia Li Peng Zhang Yancheng Liu Ruizhi Tang Zhaoguo Xing Side YaoHaiying Fu Wenfeng Wang |
| |
Institution: | a Shanghai Institute of Applied Physics, Chinese Academy of Sciences, China b Hunan University of Science and Technology, China c Graduate University of Chinese Academy of Science, Beijing 100049, China |
| |
Abstract: | GFX in water, at pH 7.0, shows intense absorption bands with peaks at 284 and 333 nm, (ε=24,670 and 12,670 M−1 cm−1). Both the absorption and emission properties of GFX were pH-dependent; the pKa values for the protonation equilibria of the ground state (5.7 and 8.9) and excited singlet state (3.6 and 7.5) of GFX were determined spectroscopically. GFX fluoresces weakly, with a maximum quantum yield for fluorescence emission (0.06) at pH 4.7. A series of experiments were performed to characterize the transient species of GFX in aqueous solution using laser flash photolysis and pulse radiolysis. GFX undergoes monophotonic photoionization with a quantum yield of 0.16 on a 355 nm laser excitation. This process leads to the formation of a long-lived cation radical with a maximum absorption at 380 nm. Triplet-triplet absorption had maximum absorption at 510 nm. The reaction of GFX with one-electron oxidant N3• was investigated and the bimolecular rate constant was determined to be 3.1×109 M−1 s−1. |
| |
Keywords: | Gatifloxacin Laser flash photolysis Triplet state Pulse radiolysis Cation radical |
本文献已被 ScienceDirect 等数据库收录! |
|