Photophysical and electrochemical redox properties of fixed distance porphyrin-quinone systems

Sen, Avijit and Krishnan, V (1999) Photophysical and electrochemical redox properties of fixed distance porphyrin-quinone systems. In: Journal of Photochemistry and Photobiology A: Chemistry, 123 (1-3). pp. 77-85.

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Abstract

A few fixed distance covalently linked porphyrin-quinone molecules have been synthesized in which a benzoquinone is directly attached to a meso/beta-pyrrole position of tri(phenyl/pentafluorophenyl)/tetraphenylporphyrins. The choice of fluoroarylporphyrins permit modulation of Delta G(ET) values for photoinduced electron-transfer reactions in these systems. All short distance porphyrin-quinone molecules showed efficient quenching of the porphyrin singlet excited state. The electrochemical redox data coupled with the steady-state and time-resolved singlet emission data are analysed to evaluate the dependence of Delta G(ET) values on the rate of electron transfer (k(ET)) in these systems. The meso-trifluoroarylporphyrin-quinones are found to be sensitive probes of the surrounding dielectric environment. Varying solvent polarity on the mechanism of fluorescence quenching and k(ET) values revealed that short donor-acceptor distance and the solvent dielectric relaxation properties play a dominant role. (C) 1999 Elsevier Science S.A. All rights reserved.

Item Type:	Journal Article
Publication:	Journal of Photochemistry and Photobiology A: Chemistry
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Porphyrin-quinone systems;Time-resolved studies;Electron transfer;Redox-properties
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	28 Jun 2011 09:35
Last Modified:	28 Jun 2011 09:35
URI:	http://eprints.iisc.ac.in/id/eprint/38721

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