36909-52-1Relevant articles and documents
Photochemistry of Benzophenone in Aliphatic Amines Studied by Laser Photolysis in the Temperature Range 300-77 K
Hoshino, Mikio,Shizuka, Haruo
, p. 714 - 718 (1987)
Laser photolysis studies of benzophenone in both sec-butylamine and triethylamine were carried out in the temperature range 300-77 K.For the sec-butylamine solution of benzophenone, the transients observed after laser pulsing are found to be the ketyl and anion radicals of benzophenone.The ratio of the yield for the formation of ketyl radical to that of the anion radical is markedly dependent on temperature: the ketyl radical is the major product at high temperatures while the anion radical becomes predominant at low temperatures.On the other hand, the triethylamine solution of benzophenone gives solely the ketyl radical as a photoproduct in the temperature range studied.The photochemical reaction of benzophenone in both sec-butylamine and triethylamine is markedly suppressed on going from high to low temperatures.These results are discussed in detail on the basis of the photochemical reaction mechanism involving the formation of the triplet charge-transfer complex (i.e., triplet exciplex) between triplet benzophenone and an amine molecule.The solvent effects on the photoreaction are also discussed.
Diffusion of electrically neutral radicals and anion radicals created by photochemical reactions
Okamoto, Koichi,Hirota, Noboru,Terazima, Masahide
, p. 185 - 194 (2007/10/03)
Diffusion processes of the intermediate radicals created by the photochemical reactions of ketones in alcoholic solvents are investigated by using the transient grating (TG) method. The electrically neutral radicals and the anion radicals of acetophenone, benzaldehyde, xanthone, benzophenone and benzil were created selectively by controlling the concentration of sodium hydroxide (NaOH) in alcoholic solvents. The translational diffusion constants (D) of the anion radicals, the neutral radicals, and the parent stable molecules can be successfully measured under the same conditions by this method. It is found that both the neutral and anion radicals diffuse slower than the parent molecules. Values of D of the anion radicals, the neutral radicals and the parent molecules are compared in detail in wide ranges of solvent viscosities, solute sizes and temperatures. Under any conditions, D values of the charged radicals are similar to those of the neutral radicals. A possible origin of such a similarity is discussed in term of the intermolecular charge polarizabilities of the radicals.
Medium Effects in the Electroreduction of Benzophenone in Aprotic Solvents
Fawcett, W. Ronald,Fedurco, Milan
, p. 7075 - 7080 (2007/10/02)
The kinetics of electroreduction of benzophenone have been studied at a mercury ultramicroelectrode in seven aprotic solvents.In addition, the temperature dependence of the standard rate constant was determined in three solvents, and the effect of tetraalkylammonium cations on the kinetic parameters was assessed in acetonitrile.On the basis of an analysis of the solvent effects, it is shown that this fast electron-transfer reaction is adiabatic.A model for solvation of the activated complex based on three contiguous spheres corresponding to the two phenyl rings and the carbonyl group is described and used to assess the outer-sphere contribution to the Gibbs activation energy for electron transfer.
Photochemistry of diphenylkeyl radicals in polar solvents
Redmond,Scaiano,Johnston
, p. 398 - 402 (2007/10/02)
The photolysis of diphenylketyl radicals in acetonitrile leads to their photobleaching with a quantum yield of 0.10. The decay of the excited radicals occurs by four different pathways; (a) doublet-doublet fluorescence; (b) radiationless decay; (c) electron photoejection, which accounts for 20% of the observed bleaching; (d) O-H bond cleavage leading to benzophenone, which is presumed to account for the remaining 80% of the bleaching. The electrons produced in acetonitrile are trapped by ground-state benzophenone to yield its radical (λmax 710 nm); addition of electron scavengers (N2O or acetone) the formation of Ph2CO*-.
