Study of the transfer of electrons and hydrogen atoms between substituted p-benzoquinone triplets and diphenylamine by flash-photolysis methods

Journal Article · Thu Jan 01 04:00:00 EST 1981 · Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.); (United States)

DOI:https://doi.org/10.1007/BF00950274· OSTI ID:5453290

Levin, P P; Kokrashvili, T A

The primary and secondary aromatic amines quench the triplet states of carbonyl compounds through processes involving the transfer of charges and hydrogen atoms. The interaction of the benzophenone triplet with primary and secondary aromatic amines involves a one-step transfer of H atoms, and leads to the formation of ketyl and aminyl radicals in both polar and nonpolar solvents. The triplet state of 2,6-diphenyl-1,4-benzoquinone can be quenched through diphenylamine (DPA), a secondary aromatic amine, the quenching mechanism involving a diffusion-limited transfer of both charges and H atoms. The processes of electron and H atom transfer are in competition here, proceeding independently in the collision complex. Neutral radicals and short-lived radical-ion pairs (t approx. 100 nsec) are formed as the result of quenching in low-polarity solvents. Both neutral and charged radicals are formed through quenching in acetonitrile, but only radical-ions are formed through quenching in alcoholic solution. Only charged radicals are formed through quenching of duroquinone by DPA in ethanol-water mixtures. An understanding of the factors determining the mechanism of carbonyl compound triplet state quenching by electron and H atom donors can be obtained through a study of the effect of the structures of the reacting molecules, and the solvent, on the kinetics of the transfer processes. The present work has used flash photolysis methods to study the intermediates formed during the quenching of the triplet states of the p-benzoquinones by DFA in solvents of various polarities.

• Research Organization: Academy of Sciences of the USSR, Moscow
• OSTI ID: 5453290
• Journal Information: Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.); (United States), Journal Name: Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.); (United States) Vol. 30:6; ISSN BACCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
AMINES
AROMATICS
BENZOQUINONES
CHARGE EXCHANGE
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ELECTRON TRANSFER
EXPERIMENTAL DATA
HYDROGEN TRANSFER
INFORMATION
MULTIPLETS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
QUANTITATIVE CHEMICAL ANALYSIS
QUENCHING
QUINONES
RADICALS
REACTION INTERMEDIATES
SPECTRA
TRIPLETS