title: [Nature of the electron-excited state in redox reactions of pigments. I. Photooxidation of chlorophyll a by n-benzoquine].
abstract: A method for studying the nature of electronic excited state under photooxidation is proposed. It is shown by an example of the oxidation of chlorophyll a with p-benzoquinone that the formation of cation-radicals of pigments proceeds only through the triplet state. On the basis of experimental data the values of the rate constants of formation of chlorophyll cation-radicals through the singlet-excited state (K2(1)--10(7) M-1 s-1) and triplet state (Kr=10(9) M-1 s-1) of the pigment are evaluated.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002734:Chlorophyll; D004583:Electrons; D007700:Kinetics; D008027:Light; D010084:Oxidation-Reduction; D011809:Quinones
chemical_list: D011809:Quinones; D002734:Chlorophyll
vernacular_title: Priroda élektronno-vozbuzhdennogo sostoianiia v okislitel'no-vosstanovitel'nykh reaktsiiakh pigmentov. I. Fotookislenie khlorofilla a n-benzokhimonom.