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Reorganization energy of supramolecular donor–acceptor dyad of octaethylporphyrin isomers and axial-coordinated acceptor: Experimental and computational study

Paper ID Volume ID Publish Year Pages File Format Full-Text
27580 44030 2011 7 PDF Available
Title
Reorganization energy of supramolecular donor–acceptor dyad of octaethylporphyrin isomers and axial-coordinated acceptor: Experimental and computational study
Abstract

The internal reorganization energy (λV) of photoinduced electron transfer (ET) in the supramolecular donor–acceptor dyads of 2,3,7,8,12,13,17,18-octaethylporphinatozinc(II) (ZnOEP) and electron acceptor ligands was compared with those of structural isomers, 2,3,7,8,11,12,17,18-octaethylhemiporphycenatozinc(II) (ZnHPc) and 2,3,6,7,12,13,16,17-octaethylporphycenatozinc(II) (ZnPcn). First, ET process of the supramolecular donor–acceptor dyads of ZnOEP was investigated by means of the transient absorption spectroscopy mainly. The formation of supramolecular dyads was confirmed by absorption spectral change, from which the association constant was estimated. The ET process was confirmed by the observation of radical cation of ZnOEP during the laser flash photolysis. The ET rates of these dyads are in the order of ZnOEP > ZnHPc > ZnPcn, when the driving forces for ET are similar to each other. From the free energy dependence of ET rates, the λV values of OEP and its isomers were estimated. The estimated λV value was in the order of ZnOEP < ZnHPc < ZnPcn. This tendency was reproduced by calculation at B3LYP/6-31G(d) and BHandHLYP/6-31G(d) levels. The origin of this tendency was discussed on the basis of the structural change during the ET process.

Keywords
Electron transfer; Reorganization energy; Porphyrin; Porphycene; Hemiporphycene; Marcus theory
First Page Preview
Reorganization energy of supramolecular donor–acceptor dyad of octaethylporphyrin isomers and axial-coordinated acceptor: Experimental and computational study
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 217, Issue 1, 1 January 2011, Pages 242–248
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering