title: Excited complexes in oxidation-reduction photoreactions of pigments. I. Spectral detection of triplet state exciplex in the chlorophyll oxidation reaction.
abstract: Photooxidation of chlorophyll "a" with p-benzoquinone in toluene and dioxane is studied by the method of flash photolysis. It is shown that in nonpolar medium the triplet exiplex is the product of this reaction. The experiments on competitive quenching of chlorophyll triplet state with naphthacene prove the diffusion mechanism of exiplex formation. The spectrum of triplet-triplet absorption of the exiplex is presented and the rate constant of intercombination degradation equalling 1.103 sec(-1) is measured. Possible structure of the exiplex is discussed.
mesh_terms: D002734:Chlorophyll; D010777:Photochemistry; D011809:Quinones; D013057:Spectrum Analysis
chemical_list: D011809:Quinones; D002734:Chlorophyll
vernacular_title: Vozbuzhdennye kompleksy v okislitel'no-vosstanovitel'nykh fotoreaktsiiakh pigmentov. I. Spektral'noe obnaruzhenie éksipleksa v tripletnom sostoianii v reaktsii okisleniia khlorofilla