Structural effects on photoinduced electron transfer in carotenoid-porphyrin-quinone triads

Darius Kuciauskas, Paul A. Liddell, Su Chun Hung, Su Lin, Simon Stone, Gilbert R. Seely, Ana L Moore, Thomas A Moore, John Devens Gust

Research output: Contribution to journalArticle

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Abstract

meso-Polyarylporphyrins are often used as components of molecules that mimic photosynthetic reaction centers by carrying out photoinduced electron-transfer reactions. Studies of these systems have raised questions concerning the role of alkyl substituents at the "β-pyrrolic" positions on the porphyrin periphery in limiting π-π overlap between the macrocycle and the aryl rings. The degree of overlap affects electronic coupling and, therefore, the rates of electron-transfer reactions. There is also evidence that when the linkages joining porphyrins to electron-acceptor or -donor moieties contain amide bonds, the sense of the amide linkage may strongly affect electron-transfer rate constants. In this study, three carotenoid-porphyrin-quinone molecular triads and various model compounds have been prepared, and electron-transfer has been studied using time-resolved emission and absorption techniques. The results show that steric hindrance due to methyl groups at the β-pyrrolic positions reduces electron-transfer rate constants by a factor of ∼1/5. In addition, amide-containing donor-acceptor linkages having the nitrogen atom attached to the porphyrin meso-aryl ring demonstrate electron-transfer rate constants ∼30 times larger than those for similar linkages with the amide reversed, after correction for thermodynamic effects.

Original languageEnglish
Pages (from-to)429-440
Number of pages12
JournalJournal of Physical Chemistry B
Volume101
Issue number3
Publication statusPublished - Jan 16 1997

Fingerprint

carotenoids
Porphyrins
quinones
Carotenoids
porphyrins
electron transfer
linkages
amides
Electrons
Amides
Rate constants
Photosynthetic Reaction Center Complex Proteins
rings
nitrogen atoms
benzoquinone
Joining
Nitrogen
thermodynamics
Thermodynamics
Atoms

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Engineering(all)

Cite this

Kuciauskas, D., Liddell, P. A., Hung, S. C., Lin, S., Stone, S., Seely, G. R., ... Gust, J. D. (1997). Structural effects on photoinduced electron transfer in carotenoid-porphyrin-quinone triads. Journal of Physical Chemistry B, 101(3), 429-440.

Structural effects on photoinduced electron transfer in carotenoid-porphyrin-quinone triads. / Kuciauskas, Darius; Liddell, Paul A.; Hung, Su Chun; Lin, Su; Stone, Simon; Seely, Gilbert R.; Moore, Ana L; Moore, Thomas A; Gust, John Devens.

In: Journal of Physical Chemistry B, Vol. 101, No. 3, 16.01.1997, p. 429-440.

Research output: Contribution to journalArticle

Kuciauskas, D, Liddell, PA, Hung, SC, Lin, S, Stone, S, Seely, GR, Moore, AL, Moore, TA & Gust, JD 1997, 'Structural effects on photoinduced electron transfer in carotenoid-porphyrin-quinone triads', Journal of Physical Chemistry B, vol. 101, no. 3, pp. 429-440.
Kuciauskas D, Liddell PA, Hung SC, Lin S, Stone S, Seely GR et al. Structural effects on photoinduced electron transfer in carotenoid-porphyrin-quinone triads. Journal of Physical Chemistry B. 1997 Jan 16;101(3):429-440.
Kuciauskas, Darius ; Liddell, Paul A. ; Hung, Su Chun ; Lin, Su ; Stone, Simon ; Seely, Gilbert R. ; Moore, Ana L ; Moore, Thomas A ; Gust, John Devens. / Structural effects on photoinduced electron transfer in carotenoid-porphyrin-quinone triads. In: Journal of Physical Chemistry B. 1997 ; Vol. 101, No. 3. pp. 429-440.
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