Free energy dependence of photoinduced charge separation rates in porphyrin dyads

Journal Article · Thu Feb 17 00:00:00 EST 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100058a007· OSTI ID:5065853

DeGraziano, J M; Liddell, P A; Leggett, L; Moore, A L; Moore, T A; Gust, D ^[1]

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1. Arizona State Univ., Tempe, AZ (United States)

A series of covalently linked porphyrin dyads in which the thermodynamic driving force for interporphyrin photoinduced charge separation spans a range of 1.13 eV has been prepared. Time-resolved fluorescence studies have yielded 22 rate constants for photoinduced electron transfer in dichloromethane solution ranging from 4.1 [times] 10[sup 7] to 5.0 [times] 10[sup 11] s[sup [minus]1]. The data are consistent with the theoretical treatments of Marcus and Levich, although there is no evidence for inverted behavior. In the normal region, electron transfer between free base porphyrin moieties is about 4 times faster than transfer involving a zinc porphyrin and having the same thermodynamic driving force, based on electrochemical measurements. Photoinduced electron transfer to an excited singlet state and electron transfer from an excited singlet state have the same dependence upon free energy change. 26 refs., 3 figs., 1 tab.

• DOE Contract Number: FG02-88ER13969
• OSTI ID: 5065853
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 98:7; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PHOTOCHEMICAL REACTIONS
THERMODYNAMICS
PORPHYRINS
ELECTRON TRANSFER
ELECTROCHEMISTRY
FLUORESCENCE
FREE ENERGY
METHYLENE CHLORIDE
SOLUTIONS
ZINC COMPLEXES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DISPERSIONS
ENERGY
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LUMINESCENCE
MIXTURES
ORGANIC ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
400201* - Chemical & Physicochemical Properties
400500 - Photochemistry
400400 - Electrochemistry