Photoinduced electron transfer between sulfur-containing carboxylic acids and the 4-carboxybenzophenone triplet state in aqueous solution

Journal Article · Thu May 05 04:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100069a014· OSTI ID:7267368

Marciniak, B ^[1]; Bobrowski, K; Hug, G L ^[2]; Rozwadowski, J ^[3]

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1. Univ. of Notre Dame, IN (United States) A. Mickiewicz Univ., Poznan (Poland)
2. Univ. of Notre Dame, IN (United States)
3. A. Mickiewicz Univ., Poznan (Poland)

The mechanism of photoinduced electron transfer was investigated using laser flash photolysis and steady-state photolysis techniques. Bimolecular rate constants for quenching of the CB triplet state by six sulfur-containing acids, with varying numbers of COO[sup [minus]] groups and varying locations with respect to the sulfur atom, were found to be in the range (0.3-2.1) x 10[sup 9]M[sup [minus]1] s[sup [minus]1] depending on the charge of the acid molecule. The observation of ketyl radical anions and intermolecular (S S)-bonded radical cations of some of the acids was direct evidence for the participation of electron transfer in the mechanism of quenching. An additional absorption band at approximately 410 nm in the transient absorption spectra for some of the acids was assigned to intramolecularly (S O)-bonded species (for acids for which a five-member ring structure was sterically favorable). Quantum yields of formation of intermediates from flash photolysis experiments and quantum yields of CO[sub 2] formation and CB disappearance from the steady-state measurements were determined. The values of these quantum yields clearly indicated that the diffusion apart (escape of the radical ions) of the charge-transfer complex, formed as a primary photochemical step, is the main photochemical pathway. 29 refs., 4 figs., 3 tabs.

• OSTI ID: 7267368
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:18; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
ABSORPTION SPECTRA
AQUEOUS SOLUTIONS
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
DISPERSIONS
ELECTRON TRANSFER
INFORMATION
KETONES
KINETICS
LASERS
MIXTURES
MULTIPLETS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADICALS
REACTION KINETICS
SOLUTIONS
SPECTRA
THEORETICAL DATA
TRIPLETS