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Spectroscopic Properties of Fluoroquinolone Antibiotics in Water–methanol and Water–acetonitrile Mixed Solvents ¶
Author(s) -
Park HyoungRyun,
Oh ChuHa,
Lee HyeongChul,
Lee JinKi,
Yang Kiyull,
Bark KiMin
Publication year - 2002
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2002)0750237spofai2.0.co2
Subject(s) - solvatochromism , chemistry , solvation , solvent , acetonitrile , solvent effects , hydrogen bond , polarizability , excited state , photochemistry , intramolecular force , analytical chemistry (journal) , molecule , organic chemistry , physics , nuclear physics
The fluorescence properties of ofloxacin (OFL), norfloxacin (NOR) and flumequine (FLU) were studied in H 2 O–CH 3 OH and H 2 O–CH 3 CN mixed solvents because these solvents were thought to behave as a biological mimetic system. The emission spectra of OFL and NOR were very sensitive to the composition of the solvents. In the Lippert–Mataga analysis of the steady‐state fluorescence data of OFL and NOR, clear reverse solvatochromism was exhibited in both mixed solvents. This observation can be explained by the twisted excited‐state intramolecular charge transfer, which is accelerated by water. Theoretical treatments further support these results. The radiative and nonradiative rate constants were analyzed as a function of solvent dipolarity–polarizability (π*) and hydrogen‐bond donor acidity (α). These results were well consistent with the suggested mechanism of the excited‐state chemical process of OFL and NOR, which depended upon the solvent–solute interactions such as bulk dielectric effects and specific hydrogen‐bonding interactions. However, the influence of dielectric effects was more significant. The solvent structures of H 2 O–CH 3 CN and the preferential solvation by water were also examined. The emission spectra of FLU do not exhibit any characteristic responses to the properties of the environment.