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Synthesis, aggregation and photoinduced electron transfer processes of cationic water-soluble 21-thia and 21-oxaporphyrins

Paper ID Volume ID Publish Year Pages File Format Full-Text
27773 44042 2008 12 PDF Available
Title
Synthesis, aggregation and photoinduced electron transfer processes of cationic water-soluble 21-thia and 21-oxaporphyrins
Abstract

The meso-pyridyl 21-thia- and 21-oxaporphyrins containing three pyridyl groups at the meso-positions have been methylated to obtain water-soluble porphyrins. The porphyrins are highly soluble in water and the water-soluble 21-thiaporphyrins exhibit aggregation behaviour above 10−4 M whereas the water-soluble 21-oxaporphyrins strongly aggregate at very low concentrations (10−7 M). The interaction of water-soluble ionic porphyrins with ionic surfactant in aqueous solutions has been studied as a function of surfactant concentration by means of absorption, fluorescence and resonance light scattering (RLS) techniques. It has been observed that, at the initial premicellar surfactant concentration, the oppositely charged surfactant induces aggregation and above cmc these aggregates dissociates into monomeric form and gets micellised. The self- and SDS-induced aggregation of these cationic porphyrins is found to depend on the number and position of the positive charge with respect to the porphyrin core. The micellar encapsulation technique is used to promote the photoinduced electron transfer between the porphyrins and neutral aromatic amines and it has been observed that the electron transfer rate becomes slowing down at the micellar surface compared to the bulk acetonitrile solution.

Keywords
Core-modified water-soluble porphyrins; Photoinduced electron transfer; Aggregation; Resonance light scattering (RLS); Micelle; Fluorescence quenching
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Synthesis, aggregation and photoinduced electron transfer processes of cationic water-soluble 21-thia and 21-oxaporphyrins
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 193, Issues 2–3, 25 January 2008, Pages 166–177
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
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