Increasing the Yield of Photoinduced Charge Separation through Parallel Electron Transfer Pathways

Nyangenya I. Maniga, John P. Sumida, Simon Stone, Ana L Moore, Thomas A Moore, John Devens Gust

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A strategy for increasing the yield of long-lived photoinduced charge separation in artificial photosynthetic reaction centers which is based on multiple electron transfer pathways operating in parallel has been investigated. Excitation of the porphyrin moiety of a carotenoid (C)-porphyrin (P)-naphthoquinone (Q) molecular triad leads to the formation of a charge-separated state C•+-P-Q•- with an overall quantum yield of 0.044 in benzonitrile solution. Photoinduced electron transfer from the porphyrin first excited singlet state gives C-P•+-Q•- with a quantum yield of ∼1.0. However, electron transfer from the carotenoid to the porphyrin radical cation to form the final state does not compete well with charge recombination of C-P•+-Q•-, reducing the yield. The related pentad C3-P-Q features carotenoid, porphyrin and quinone moieties closely related to those in the triad. Excitation of this molecule gives a C•+-P(C2)-Q•- state with a quantum yield of 0.073. The enhanced yield is ascribed to the fact that three electron donation pathways operating in parallel compete with charge recombination. The yield does not increase by the statistically predicted factor of three owing to small differences in thermodynamic driving force between the two compounds.

Original languageEnglish
Pages (from-to)32-44
Number of pages13
JournalJournal of Porphyrins and Phthalocyanines
Volume3
Issue number1
Publication statusPublished - Jan 1999

Fingerprint

Porphyrins
Quantum yield
Carotenoids
Electrons
Photosynthetic Reaction Center Complex Proteins
Naphthoquinones
Excited states
Cations
Thermodynamics
Molecules

Keywords

  • Carotenoid
  • Photoinduced electron transfer
  • Porphyrin
  • Quinone
  • Spectroscopy
  • Synthesis

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Increasing the Yield of Photoinduced Charge Separation through Parallel Electron Transfer Pathways. / Maniga, Nyangenya I.; Sumida, John P.; Stone, Simon; Moore, Ana L; Moore, Thomas A; Gust, John Devens.

In: Journal of Porphyrins and Phthalocyanines, Vol. 3, No. 1, 01.1999, p. 32-44.

Research output: Contribution to journalArticle

@article{097429c91af54b26a87abad132437127,
title = "Increasing the Yield of Photoinduced Charge Separation through Parallel Electron Transfer Pathways",
abstract = "A strategy for increasing the yield of long-lived photoinduced charge separation in artificial photosynthetic reaction centers which is based on multiple electron transfer pathways operating in parallel has been investigated. Excitation of the porphyrin moiety of a carotenoid (C)-porphyrin (P)-naphthoquinone (Q) molecular triad leads to the formation of a charge-separated state C•+-P-Q•- with an overall quantum yield of 0.044 in benzonitrile solution. Photoinduced electron transfer from the porphyrin first excited singlet state gives C-P•+-Q•- with a quantum yield of ∼1.0. However, electron transfer from the carotenoid to the porphyrin radical cation to form the final state does not compete well with charge recombination of C-P•+-Q•-, reducing the yield. The related pentad C3-P-Q features carotenoid, porphyrin and quinone moieties closely related to those in the triad. Excitation of this molecule gives a C•+-P(C2)-Q•- state with a quantum yield of 0.073. The enhanced yield is ascribed to the fact that three electron donation pathways operating in parallel compete with charge recombination. The yield does not increase by the statistically predicted factor of three owing to small differences in thermodynamic driving force between the two compounds.",
keywords = "Carotenoid, Photoinduced electron transfer, Porphyrin, Quinone, Spectroscopy, Synthesis",
author = "Maniga, {Nyangenya I.} and Sumida, {John P.} and Simon Stone and Moore, {Ana L} and Moore, {Thomas A} and Gust, {John Devens}",
year = "1999",
month = "1",
language = "English",
volume = "3",
pages = "32--44",
journal = "Journal of Porphyrins and Phthalocyanines",
issn = "1088-4246",
publisher = "Society of Porphyrins and Phthalocyanines (SPP)",
number = "1",

}

TY - JOUR

T1 - Increasing the Yield of Photoinduced Charge Separation through Parallel Electron Transfer Pathways

AU - Maniga, Nyangenya I.

AU - Sumida, John P.

AU - Stone, Simon

AU - Moore, Ana L

AU - Moore, Thomas A

AU - Gust, John Devens

PY - 1999/1

Y1 - 1999/1

N2 - A strategy for increasing the yield of long-lived photoinduced charge separation in artificial photosynthetic reaction centers which is based on multiple electron transfer pathways operating in parallel has been investigated. Excitation of the porphyrin moiety of a carotenoid (C)-porphyrin (P)-naphthoquinone (Q) molecular triad leads to the formation of a charge-separated state C•+-P-Q•- with an overall quantum yield of 0.044 in benzonitrile solution. Photoinduced electron transfer from the porphyrin first excited singlet state gives C-P•+-Q•- with a quantum yield of ∼1.0. However, electron transfer from the carotenoid to the porphyrin radical cation to form the final state does not compete well with charge recombination of C-P•+-Q•-, reducing the yield. The related pentad C3-P-Q features carotenoid, porphyrin and quinone moieties closely related to those in the triad. Excitation of this molecule gives a C•+-P(C2)-Q•- state with a quantum yield of 0.073. The enhanced yield is ascribed to the fact that three electron donation pathways operating in parallel compete with charge recombination. The yield does not increase by the statistically predicted factor of three owing to small differences in thermodynamic driving force between the two compounds.

AB - A strategy for increasing the yield of long-lived photoinduced charge separation in artificial photosynthetic reaction centers which is based on multiple electron transfer pathways operating in parallel has been investigated. Excitation of the porphyrin moiety of a carotenoid (C)-porphyrin (P)-naphthoquinone (Q) molecular triad leads to the formation of a charge-separated state C•+-P-Q•- with an overall quantum yield of 0.044 in benzonitrile solution. Photoinduced electron transfer from the porphyrin first excited singlet state gives C-P•+-Q•- with a quantum yield of ∼1.0. However, electron transfer from the carotenoid to the porphyrin radical cation to form the final state does not compete well with charge recombination of C-P•+-Q•-, reducing the yield. The related pentad C3-P-Q features carotenoid, porphyrin and quinone moieties closely related to those in the triad. Excitation of this molecule gives a C•+-P(C2)-Q•- state with a quantum yield of 0.073. The enhanced yield is ascribed to the fact that three electron donation pathways operating in parallel compete with charge recombination. The yield does not increase by the statistically predicted factor of three owing to small differences in thermodynamic driving force between the two compounds.

KW - Carotenoid

KW - Photoinduced electron transfer

KW - Porphyrin

KW - Quinone

KW - Spectroscopy

KW - Synthesis

UR - http://www.scopus.com/inward/record.url?scp=0002106333&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0002106333&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0002106333

VL - 3

SP - 32

EP - 44

JO - Journal of Porphyrins and Phthalocyanines

JF - Journal of Porphyrins and Phthalocyanines

SN - 1088-4246

IS - 1

ER -