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Photophysical properties of novel cationic naphthalimides

Paper ID Volume ID Publish Year Pages File Format Full-Text
29065 44117 2006 8 PDF Available
Title
Photophysical properties of novel cationic naphthalimides
Abstract

Novel positively charged naphthalimide derivatives were synthesized, in which N-methylpyridinium substituent was attached to the dicarboximide moiety. The absorption and fluorescence spectra were studied, fluorescence lifetimes, fluorescence yields and triplet yields were determined in acetonitrile and CH2Cl2. Ion-pairing was found to markedly alter the photophysical properties in the latter solvent. The association with iodide counterion decreased the radiative rate constant. The triplet formation was much more rapid for the 2,3-isomers, whereas the 1,2-derivatives emitted stronger fluorescence. The rate of internal conversion proved to be more than one order of magnitude higher for all N-methylpyridinium derivatives compared with that of the parent compounds, which might indicate that the significantly smaller energy gap between the S1 and S2 excited states led to more efficient excited state relaxation.

Keywords
Fluorescence; Internal conversion; Intersystem crossing; Excited state; Naphthalimide derivative
First Page Preview
Photophysical properties of novel cationic naphthalimides
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 182, Issue 1, 20 August 2006, Pages 99–106
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering