[Role of triplet exciplex in electron transport].

The role of triplet exciplex in electron transfer was considered in the photooxidation of chlorophylls "a" and "b" with p-benzoquinone and aromatic nitrous compounds. Relationship between the change of free energy delta F of formation of solvated ion-radical, ion-radical pairs and chlorophyll exciplex and dielectric constant of the medium & was investigated. The conclusions obtained were compared with the experimental data on the intermediate products. It was found that photooxidation of chlorophyll may proceed via the formation of the exciplex in the triplet state, while during pheophytin photooxidation no exciplex is formed and the first stage of electron transfer is the formation of the ion-radical pair.