Stepwise sequential and parallel photoinduced charge separation in a porphyrin-triquinone tetrad

Joseph Springer, Gerdenis Kodis, Linda De la Garza, Ana L Moore, Thomas A Moore, John Devens Gust

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

A molecular tetrad consisting of a free base porphyrin (P) linked to a triquinone moiety consisting of a naphthoquinone bearing two benzoquinones (NQ-BQ2) has been synthesized and its photochemistry has been investigated using time-resolved spectroscopic techniques. Excitation of the porphyrin chromophore of the P-NQ-BQ2 tetrad in benzonitrile solution is followed by photoinduced electron transfer with a rate constant of 8.3 × 1010 s-1 to produce an initial P.+-NQ.--BQ2 state with a quantum yield of unity. A charge shift reaction gives a final P.+-NQ-(BQ.-BQ) charge-separated state, which decays to the ground state with a rate constant of 1.9 × 1010 s-1. The tetrad features both sequential and parallel multistep electron-transfer pathways. No evidence was found for significant involvement of direct electron transfer from the porphyrin first excited singlet state to a benzoquinone.

Original languageEnglish
Pages (from-to)3567-3575
Number of pages9
JournalJournal of Physical Chemistry A
Volume107
Issue number18
DOIs
Publication statusPublished - May 8 2003

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Porphyrins
polarization (charge separation)
porphyrins
electron transfer
quinones
Electrons
Rate constants
Bearings (structural)
Benzoquinones
Naphthoquinones
Photochemical reactions
Quantum yield
Chromophores
Excited states
photochemical reactions
Ground state
chromophores
excitation
unity
ground state

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Stepwise sequential and parallel photoinduced charge separation in a porphyrin-triquinone tetrad. / Springer, Joseph; Kodis, Gerdenis; De la Garza, Linda; Moore, Ana L; Moore, Thomas A; Gust, John Devens.

In: Journal of Physical Chemistry A, Vol. 107, No. 18, 08.05.2003, p. 3567-3575.

Research output: Contribution to journalArticle

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AU - Gust, John Devens

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