Picosecond and nanosecond studies of the photoreduction of benzophenone by N,N-diethylaniline and triethylamine

Journal Article · Thu Sep 19 00:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100172a030· OSTI ID:5156751

Devadoss, C; Fessenden, R W ^[1]

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1. Univ. of Notre Dame, IN (United States)

The photoreduction of benzophenone by N,N-diethylaniline and triethylamine has been examined in a number of solvents by both nano- and picosecond laser photolysis. With diethylaniline, electron transfer is the primary step and the spectrum of the ion pair has been detected even in nonpolar solvents such as benzene and cyclohexane. Rapid proton transfer then takes place to form a high yield of the ketyl radical. The lifetime of the ion pair in benzene is about 900 ps. In acetonitrile, the ion pair dissociated into individual ions which then decay by back electron transfer and proton transfer. A spectral shift to the red occurs over 100 ps as the contact ion pair dissociated. In acidic alcohols such as methanol and trifluoroethanol, proton transfer from the alcohol occurs to produce the ketyl radical. In the case of triethylamine, no distinct absorption band for benzophenone anion was seen in picosecond experiments but difference spectra, which removed much of the spectrum of benzophenone triplet, clearly showed some contribution from the anion. For this compound, it is likely that electron transfer occurs first followed by very fast proton transfer.

• OSTI ID: 5156751
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:19; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTROSCOPY
ALKYLATED AROMATICS
AMINES
ANIONS
AROMATICS
BARYONS
BENZOPHENONE
CATIONS
CHARGED PARTICLES
CHEMICAL REACTIONS
DATA
ELECTRON TRANSFER
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
HADRONS
INFORMATION
ION PAIRS
IONS
KETONES
NUCLEONS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PROTONS
RADICALS
REDUCTION
RESOLUTION
SOLVENTS
SPECTRA
SPECTROSCOPY
TIME DEPENDENCE
TIME RESOLUTION
TIMING PROPERTIES
VISIBLE SPECTRA