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Photophysical behavior of lipophilic xanthene dyes without the involvement of photoinduced electron transfer mechanism

Paper ID Volume ID Publish Year Pages File Format Full-Text
29002 44112 2008 7 PDF Available
Title
Photophysical behavior of lipophilic xanthene dyes without the involvement of photoinduced electron transfer mechanism
Abstract

The correlation of dibutyl-ether-ester of xanthene dye structures with their photophysical properties is discussed with respect to their capability as fluorescent probes based on ultraviolet–visible absorption, fluorescence spectra and fluorescence lifetimes measured in different solvents. It was found that the dibutyl-ether-ester of fluorescein is very weakly emissive in aprotic solvents, but fairly strong fluorescent in alcohols. The dependence of fluorescence quantum yield (Φf) and lifetime (τf) on solvent polarity suggests non-involvement of the intra-molecular photoinduced electron transfer (PeT) mechanism, suggested previously to account for the emission efficiency of fluorescein derivatives. The xanthene dyes intend to self-assemble in aprotic solvents, less polar solvents facilitate the aggregation while hydrogen bonding disfavor it. The formation of non-emissive H-aggregates is proposed to be responsible for their fluorescent behavior. The esterification showed stronger influences on the photophysics than the etherification, i.e. the former caused larger reduction of Φf owing to the internal conversion. The halogenation decreases the fluorescence quantum yield and lifetime of the xanthene dyes, owing to the enhancement of inter-system crossing process.

Keywords
Xanthene dye; Fluorescein; Fluorescence; Aggregation; Lipase
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Photophysical behavior of lipophilic xanthene dyes without the involvement of photoinduced electron transfer mechanism
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 200, Issues 2–3, 15 December 2008, Pages 307–313
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
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