The quantum yields of fluorescence and phosphorescence and the triplet lifetimes were determined for 29 phenothiazine derivatives: the phi p values are varying from 0.2 to 1. The irradiation of phenothiazine derivatives in aerated solutions yields from the triplet state to the formation of singlet oxygen and more especially of superoxide ions and cation-radicals characteristic of the dye. Relative values of the formation rate were determined for these two mechanisms. Production of cation-radicals was correlated with photoxicity in vivo. Chlorination enhances the two phenomena and acetylation reduces to nothing. A maximum value was estimated for the quantum yield of photoionization.

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The evolution of the proflavine triplet state population with the extent of aggregation is examines, by ESRmeasurements, as a function of organic solvents and mineral salts, well known for their ability to influence the aggregation process. The intensity of the triplet state population has also been investigated as a function of pH. The insertion of aromatic molecules like DNA's nucleotides between dye molecules is shown to increase the intensity of the triplet state. It is put forward that the observed triplet state is characteristic of the singly protonated proflavine which seems to be the active species in in vivo experiments.

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Les auteurs mettent en évidence la formation de complexes par transfert de charge entre, d'une part, certains représentants de substances naturelles, à savoir les amines biogènes, et de substances synthétiques utilisées comme médicaments, essentiellement les parasympathicomimétiques, les neuroleptiques et les thyméréthiques, fonctionnant comme donneurs et, d'autre part, le chloranile, fonctionnant comme accepteur. L'étude de ces complexes est fondée sur l'analyse de leurs spectres optiques caractéristiques. Dans les cas de l'histamine et de la chlorpromazine, une nouvelle bande, spécifique du complexe formé, est observée. Mais, en général, le transfert de charge en cause conduit à l'ionisation des constituants, ce qui se manifeste par l'apparition des bandes d'absorption propres à l'ion chloranile.