Solvent effects on the energetics and dynamics of ultrafast electron transfer in chlorophyll-porphyrin-acceptor triads

Gary P. Wiederrecht, Shigeru Watanabe, Michael R Wasielewski

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The photochemistry and electron transfer kinetics of two fixed distance and fixed orientation triad systems are studied. The two molecules are a zinc-chlorophyll-zinc-porphyrin-naphthoquinone (ZCZPNQ) system and a zinc-chlorophyll-zinc-porphyrin-3,4,9,10-perylenetetracarboxydiimide (ZCZPPER) system. Optical excitation of ZC with a 190 fs pulse at 585 nm results in charge transfer and the formation of ZC+ZPNQ- (PER-). The chromophores are chosen to minimize spectral overlap of the radical ion products, so that the analysis of the kinetic data is unambiguous. The kinetics of charge transfer are monitored by ultrafast pump-probe spectroscopy, and the role that the central porphyrin plays in mediating electron transfer is discussed. We find that solvent relaxation also plays a role in determining the rates of both charge separation and recombination in polar solvents. Differing mechanisms for solvent relaxation are discussed.

Original languageEnglish
Pages (from-to)601-614
Number of pages14
JournalChemical Physics
Volume176
Issue number2-3
DOIs
Publication statusPublished - Oct 15 1993

Fingerprint

Porphyrins
chlorophylls
Chlorophyll
porphyrins
electron transfer
zinc
Kinetics
Electrons
Charge transfer
Zinc
Naphthoquinones
kinetics
Photoexcitation
Photochemical reactions
charge transfer
Chromophores
polarization (charge separation)
Pumps
Spectroscopy
photochemical reactions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Spectroscopy
  • Atomic and Molecular Physics, and Optics

Cite this

Solvent effects on the energetics and dynamics of ultrafast electron transfer in chlorophyll-porphyrin-acceptor triads. / Wiederrecht, Gary P.; Watanabe, Shigeru; Wasielewski, Michael R.

In: Chemical Physics, Vol. 176, No. 2-3, 15.10.1993, p. 601-614.

Research output: Contribution to journalArticle

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