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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/3388
Title: Energy and electron transfer in bifunctional non-conjugated dendrimers
Authors: Thomas K.R.J.
Thompson A.L.
Sivakumar A.V.
Bardeen C.J.
Thayumanavan S.
Published in: Journal of the American Chemical Society
Abstract: Nonconjugated dendrimers, which are capable of tunneling energy from the periphery to the core followed by a charge-transfer process from the core to the periphery, have been synthesized. The energy and electron donors involve a diarylaminopyrene unit and are incorporated at the periphery of these dendrimers. The energy and electron acceptor is at the core of the dendrimer, which involves a chromophore based on a benzthiadiazole moiety. The backbone of the dendrimers is benzyl ether based. A direct electron-transfer quenching of the excited state of the periphery or a sequential energy transfer - electron-transfer pathway are the two limiting mechanisms of the observed photophysical properties. We find that the latter mechanism is prevalent in these dendrimers. The energy transfer occurs on a picosecond time scale, while the charge-transfer process occurs on a nanosecond time scale. The lifetime of the charge separated species was found to be in the range of microseconds. Energy transfer efficiencies ranging from 80% to 90% were determined using both steady-state and time-resolved measurements, while charge-transfer efficiencies ranging from 70% to 80% were deduced from fluorescence quenching of the core chromophore. The dependence of the energy and charge-transfer processes on dendrimer generation is analyzed in terms of the backfolding of the flexible benzyl ether backbone, which leads to a weaker dependence of the energy and charge-transfer efficiencies on dendrimer size than would be expected for a rigid system.
Citation: Journal of the American Chemical Society (2005), 127(1): 373-383
URI: https://doi.org/10.1021/ja044778m
http://repository.iitr.ac.in/handle/123456789/3388
Issue Date: 2005
ISSN: 27863
Author Scopus IDs: 57203389297
7404597385
8768028400
7003840634
57203195779
Author Affiliations: Thomas, K.R.J., Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States
Thompson, A.L., Department of Chemistry, University of Illinois, Urbana, IL 61801, United States
Sivakumar, A.V., Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States
Bardeen, C.J., Department of Chemistry, University of Illinois, Urbana, IL 61801, United States
Thayumanavan, S., Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States
Corresponding Author: Bardeen, C.J.; Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States; email: bardeen@scs.uiuc.edu
Appears in Collections:Journal Publications [CY]

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