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Aggregation and disaggregation of anionic aluminum phthalocyanines in cationic pre-micelle and micelle media: A fluorescence study

Paper ID Volume ID Publish Year Pages File Format Full-Text
26993 43992 2012 8 PDF Available
Title
Aggregation and disaggregation of anionic aluminum phthalocyanines in cationic pre-micelle and micelle media: A fluorescence study
Abstract

The interactions of two anionic aluminum phthalocyanines (Pcs), the tetrasulfonated (AlPcS4) and the monosulfonated (AlPcS1) species, with the cationic detergent n-dodecyltrimethylammonium chloride (DTAC) were investigated. These studies were performed by UV–visible absorption, steady-state and transient-state fluorescence, fluorescence lifetime imaging microscopy (FLIM), and fluorescence correlation spectroscopy (FCS). For both AlPcS4 and AlPcS1, large complexes of Pc–DTAC were formed at low surfactant concentrations, in the pre-micelle range. These complexes were visualized by the FLIM technique, directly in a drop of the sample. As the DTAC concentration increased, the size of the complexes decreased significantly. Above the detergent critical micelle concentration (CMC ≈ 22 mM), highly fluorescent monomers of both AlPcS4 and AlPcS1 were found to be strongly bound to the DTAC micelles surface: large equilibrium binding constants, Kb = 3.5 × 105 and 6.2 × 104, were obtained for AlPcS4 and AlPcS1, respectively. The aggregation/disaggregation behavior of phthalocyanines likely results from a delicate balance in the system, between hydrophobic attractions (Pc–Pc) and electrostatic attractions (anionic Pc macrocycles – cationic DTAC headgroups) and repulsions (between anionic sulfonated groups of Pc macrocycles).

Graphical abstractSchematic representation of the aggregation and disaggregation of anionic aluminum phthalocyanines in cationic pre-micelle and micelle media.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Aggregation/disaggregation of sulfonated phthalocyanines in surfactant media. ► Incorporation of bright monomers in surfactant micelles. ► Imaging of phthalocyanine–DTAC micro-sized complexes.

Keywords
AlPcS4, tetrasulfonated aluminum phthalocyanine; AlPcS1, monosulfonated aluminum phthalocyanine; AlPcSn, (n)-sulfonated aluminum phthalocyanine; CMC, critical micelle concentration; CTAC, cetyltrimethylammonium chloride; DTAC, n-dodecyltrimethylammonium c
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Aggregation and disaggregation of anionic aluminum phthalocyanines in cationic pre-micelle and micelle media: A fluorescence study
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 235, 1 May 2012, Pages 21–28
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us