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Environmental effects on the fluorescence behaviour of carbazole derivatization reagents
Author(s) -
RomeroAle Emiliano E.,
Olives Ana I.,
Martín M. Antonia,
del Castillo Benito,
LópezAlvarado Pilar,
Menéndez J. Carlos
Publication year - 2005
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.813
Subject(s) - carbazole , bathochromic shift , chemistry , derivatization , fluorescence , photochemistry , reagent , fluorophore , acetonitrile , solvent , organic chemistry , high performance liquid chromatography , physics , quantum mechanics
Abstract The carbazole ring is the basic structure present in the fluorescence derivatization reagents 9‐chlorocarbonylcarbazole and 9‐carbazolylacetic acid. The fluorescence behaviour of these carbazole derivatives was studied in solvents with different polarities (cyclohexane, ethanol, acetonitrile, water) and at different pH values (4.5 and 8.8). The influence of the low polarity environment afforded by 2‐hydroxypropyl‐ β ‐cyclodextrin (HP β ‐CD) is also described. The behaviour of the fluorescent reagents is compared to the model molecules carbazole and 9‐methylcarbazole. For all derivatives studied, a bathochromic shift in the fluorescence emission maxima was observed when the solvent polarity was increased. A bathochromic shift was observed in dioxane solutions, which can be ascribed to the peculiar behaviour of this solvent. The changes in the fluorescence intensity in the case of 9‐carbazolylacetic acid can be related to the ionization of the carboxylic acid group. Inclusion into the cavity of HP β ‐CD allows emission spectra to be obtained close to those obtained in ethanolic solutions with a remarkable enhancement in the fluorescence intensity, depending on the chemical structure of the carbazole derivative included. Copyright © 2005 John Wiley & Sons, Ltd.