Conformationally gated switching between superexchange and hopping within oligo-p-phenylene-based molecular wires

Emily A Weiss, Michael J. Tauber, Richard F. Kelley, Michael J. Ahrens, Mark A Ratner, Michael R Wasielewski

Research output: Contribution to journalArticle

152 Citations (Scopus)

Abstract

We observe well-defined regions of superexchange and thermally activated hopping in the temperature dependence of charge recombination (CR) in a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Phn), n = 1-4, and A = perylene-3,4:9,10- bis(dicarboximide) (PDI). A fit to the thermally activated CR rates of the n = 3 and n = 4 compounds yields activation barriers of 1290 and 2030 cm -1, respectively, which match closely with theoretically predicted and experimentally observed barriers for the planarization of terphenyl and quaterphenyl. Negative activation of CR in the temperature regions dominated by superexchange charge transport is the result of a fast conformational equilibrium that increasingly depopulates the reactive state for CR as temperature is increased. The temperature dependence of the effective donor-acceptor superexchange coupling, VDA, measured using magnetic field effects on the efficiency of the charge recombination process, shows that CR occurs out of the conformation with lower VDA via the energetically favored triplet pathway.

Original languageEnglish
Pages (from-to)11842-11850
Number of pages9
JournalJournal of the American Chemical Society
Volume127
Issue number33
DOIs
Publication statusPublished - Aug 24 2005

Fingerprint

Genetic Recombination
Wire
Temperature
Chemical activation
Perylene
Magnetic field effects
Conformations
Charge transfer
Magnetic Fields

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Conformationally gated switching between superexchange and hopping within oligo-p-phenylene-based molecular wires. / Weiss, Emily A; Tauber, Michael J.; Kelley, Richard F.; Ahrens, Michael J.; Ratner, Mark A; Wasielewski, Michael R.

In: Journal of the American Chemical Society, Vol. 127, No. 33, 24.08.2005, p. 11842-11850.

Research output: Contribution to journalArticle

@article{a55dec287c824d6f82e497c722337f3c,
title = "Conformationally gated switching between superexchange and hopping within oligo-p-phenylene-based molecular wires",
abstract = "We observe well-defined regions of superexchange and thermally activated hopping in the temperature dependence of charge recombination (CR) in a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Phn), n = 1-4, and A = perylene-3,4:9,10- bis(dicarboximide) (PDI). A fit to the thermally activated CR rates of the n = 3 and n = 4 compounds yields activation barriers of 1290 and 2030 cm -1, respectively, which match closely with theoretically predicted and experimentally observed barriers for the planarization of terphenyl and quaterphenyl. Negative activation of CR in the temperature regions dominated by superexchange charge transport is the result of a fast conformational equilibrium that increasingly depopulates the reactive state for CR as temperature is increased. The temperature dependence of the effective donor-acceptor superexchange coupling, VDA, measured using magnetic field effects on the efficiency of the charge recombination process, shows that CR occurs out of the conformation with lower VDA via the energetically favored triplet pathway.",
author = "Weiss, {Emily A} and Tauber, {Michael J.} and Kelley, {Richard F.} and Ahrens, {Michael J.} and Ratner, {Mark A} and Wasielewski, {Michael R}",
year = "2005",
month = "8",
day = "24",
doi = "10.1021/ja052901j",
language = "English",
volume = "127",
pages = "11842--11850",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "33",

}

TY - JOUR

T1 - Conformationally gated switching between superexchange and hopping within oligo-p-phenylene-based molecular wires

AU - Weiss, Emily A

AU - Tauber, Michael J.

AU - Kelley, Richard F.

AU - Ahrens, Michael J.

AU - Ratner, Mark A

AU - Wasielewski, Michael R

PY - 2005/8/24

Y1 - 2005/8/24

N2 - We observe well-defined regions of superexchange and thermally activated hopping in the temperature dependence of charge recombination (CR) in a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Phn), n = 1-4, and A = perylene-3,4:9,10- bis(dicarboximide) (PDI). A fit to the thermally activated CR rates of the n = 3 and n = 4 compounds yields activation barriers of 1290 and 2030 cm -1, respectively, which match closely with theoretically predicted and experimentally observed barriers for the planarization of terphenyl and quaterphenyl. Negative activation of CR in the temperature regions dominated by superexchange charge transport is the result of a fast conformational equilibrium that increasingly depopulates the reactive state for CR as temperature is increased. The temperature dependence of the effective donor-acceptor superexchange coupling, VDA, measured using magnetic field effects on the efficiency of the charge recombination process, shows that CR occurs out of the conformation with lower VDA via the energetically favored triplet pathway.

AB - We observe well-defined regions of superexchange and thermally activated hopping in the temperature dependence of charge recombination (CR) in a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Phn), n = 1-4, and A = perylene-3,4:9,10- bis(dicarboximide) (PDI). A fit to the thermally activated CR rates of the n = 3 and n = 4 compounds yields activation barriers of 1290 and 2030 cm -1, respectively, which match closely with theoretically predicted and experimentally observed barriers for the planarization of terphenyl and quaterphenyl. Negative activation of CR in the temperature regions dominated by superexchange charge transport is the result of a fast conformational equilibrium that increasingly depopulates the reactive state for CR as temperature is increased. The temperature dependence of the effective donor-acceptor superexchange coupling, VDA, measured using magnetic field effects on the efficiency of the charge recombination process, shows that CR occurs out of the conformation with lower VDA via the energetically favored triplet pathway.

UR - http://www.scopus.com/inward/record.url?scp=23944477885&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=23944477885&partnerID=8YFLogxK

U2 - 10.1021/ja052901j

DO - 10.1021/ja052901j

M3 - Article

VL - 127

SP - 11842

EP - 11850

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 33

ER -