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Potassium ion controlled switching of intra- to intermolecular electron transfer in crown ether appended free-base porphyrin-fullerene donor-acceptor systems

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dc.contributor Wichita State University. Department of Chemistry en_US
dc.contributor.author D'Souza, Francis en_US
dc.contributor.author Chitta, Raghu en_US
dc.contributor.author Gadde, Suresh en_US
dc.contributor.author Zandler, Melvin E. en_US
dc.contributor.author McCarty, Amy L. en_US
dc.contributor.author Sandanayaka, Atula S. D. en_US
dc.contributor.author Araki, Yasuyaki en_US
dc.contributor.author Ito, Osamu en_US
dc.date.accessioned 2012-02-06T17:16:28Z
dc.date.available 2012-02-06T17:16:28Z
dc.date.issued 2006-04-06 en_US
dc.identifier 16571036 en_US
dc.identifier 9890903 en_US
dc.identifier.citation The journal of physical chemistry. A. 2006 Apr 6; 110(13): 4338-47. en_US
dc.identifier.issn 1089-5639 en_US
dc.identifier.uri http://dx.doi.org/10.1021/jp055284u en_US
dc.identifier.uri http://hdl.handle.net/10057/4326
dc.description Click on the DOI link below to access the article (may not be free). en_US
dc.description.abstract Photoinduced electron transfer in intramolecularly interacting free-base porphyrin bearing one or four 18-crown-6 ether units at different positions of the porphyrin macrocycle periphery and pristine fullerene was investigated in polar benzonitrile and nonpolar o-dichlorobenzene and toluene solvents. Owing to the presence of two modes of binding, stable dyads were obtained in which the binding constants, K, were found to range between 4.2 x 10(3) and 10.4 x 10(3) M(-1) from fluorescence quenching data depending upon the location and number of crown ether entities on the porphyrin macrocycle and the solvent. Computational studies using the B3LYP/3-21G() method were employed to arrive at the geometry and electronic structure of the intramolecular dyads. The energetics of the redox states of the dyads were established from cyclic voltammetric studies. Under the intramolecular conditions, both the steady-state and time-resolved emission studies revealed efficient quenching of the singlet excited free-base porphyrin in these dyads, and the measured rates of charge separation, k(CS), were found to be in the 10(8)-10(9) s(-1) range. Nanosecond transient absorption studies were performed to characterize the electron-transfer products and to evaluate the charge-recombination rates. Shifting of the electron-transfer pathway from the intra- to intermolecular route was achieved by complexing potassium ions to the crown ether cavity(ies) in benzonitrile. This cation complexation weakened the intramolecular interactions between fullerene and the crown ether appended free-base porphyrin supramolecules, and under these conditions, intermolecular type interactions were mainly observed. Reversible inter- to intramolecular electron transfer was also accomplished by extracting the potassium ions of the complex with the addition of 18-crown-6. The present study nicely demonstrates the application of supramolecular methodology to control the excited-state electron-transfer path in donor-acceptor dyads. en_US
dc.format.extent 4338-47 en_US
dc.language.iso eng en_US
dc.publisher American Chemical Society en_US
dc.relation.ispartofseries The journal of physical chemistry. A en_US
dc.relation.ispartofseries J Phys Chem A en_US
dc.source NLM en_US
dc.subject Research Support, Non-U.S. Gov't en_US
dc.subject Research Support, U.S. Gov't, Non-P.H.S. en_US
dc.subject.mesh Computer Simulation en_US
dc.subject.mesh Crown Ethers/chemistry en_US
dc.subject.mesh Electrons en_US
dc.subject.mesh Fullerenes/chemistry en_US
dc.subject.mesh Ions en_US
dc.subject.mesh Models, Molecular en_US
dc.subject.mesh Molecular Structure en_US
dc.subject.mesh Porphyrins/chemistry en_US
dc.subject.mesh Potassium/chemistry en_US
dc.subject.mesh Spectrometry, Fluorescence en_US
dc.subject.mesh Static Electricity en_US
dc.title Potassium ion controlled switching of intra- to intermolecular electron transfer in crown ether appended free-base porphyrin-fullerene donor-acceptor systems en_US
dc.type Article en_US
dc.coverage.spacial United States en_US
dc.description.version peer reviewed en_US
dc.rights.holder Copyright © 2006 American Chemical Society en_US

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