Photochemistry and photophysics of phenylmethyl radicals

Journal Article · Sun Jan 01 04:00:00 EST 1984 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00322a064· OSTI ID:5771454

Bromberg, A; Schmidt, K H; Meisel, D

The photophysics of arylalkyl radicals, notably that of the prototype benzyl radical (PhCH/sub 2//sub ./), have been extensively studied. Fluorescence lifetimes and quantum yields have been experimentally measured in solid matrices at low temperatures and theoretical calculations have estimated the energy levels and the various decay modes of a variety of substituted benzyl radicals. Fluorescence from the closely related diphenylketyl radical has also been observed in a glassy matrix as well as at room temperature. For the ketyl radical the fluorescence lifetime has decreased from approx. 20 to approx. 2 ns on increasing the temperature from 77 K to room temperature, indicating a possible photochemical reaction of the excited state of the radical at the higher temperature. While the fluorescence lifetime of the benzyl and its analogue radicals at 77 K is in the range of 1.0 +/- 0.5 ..mu..s, no information is available in the literature on their fluorescence lifetime at higher temperatures. In fact, information on the photochemistry and photophysics of radicals in liquid solutions is very scarce. To bridge this gap a systematic study of such systems has been initiated. In the present communication, the room temperature lifetime, excited-state doublet-doublet and fluorescence spectra of the diphenylmethyl radical are reported as well as the photochemistry of its triphenylmethyl homologue. 18 references, 2 figures.

• Research Organization: Argonne National Lab., IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5771454
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 106; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ALKYL RADICALS
ARYL RADICALS
CHEMISTRY
DATA
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
FLUORESCENCE
INFORMATION
LIFETIME
LUMINESCENCE
NUMERICAL DATA
PHOTOCHEMISTRY
RADICALS
SPECTRA