[Absorption and fluorescence spectra of hypericin sodium salt in complexes with albumins].

The spectra of absorption and fluorescence of hypericin sodium salt (Na-Hy) in organic solvents and in complexes with human serum albumin, bovine serum albumin, and lipoproteins of low and high density have been studied. It was shown that, as the proton donor properties of the solvent enhance, the absorption and fluorescence maxima shift toward the blue region, and as the proton-accepting properties increase, the maxima shift toward the red region. The absorption spectra of complexes of Na-Hy with bovine serum albumin significantly differ from those of complexes of this ligand with human serum albumin, which is evidenced by a lesser width of absorption bands and a lower value of the Stokes shift. The positions of the absorption and fluorescence maxima and the value of the Stokes shift for the complex of Na-Hy with human serum albumin increases when D20 instead of common water is used as a solvent. It was concluded that H-bonds of hypericin play a significant role in the interaction with human serum albumin.

[Dependence of the rate of safranine photocatalytic destruction on the catalyst concentration].

The effect of the concentration of disperse titanium-containing oxide photocatalyzers on the destruction of safranine in aqueous solutions has been studied. It was found that the rate constant of safranine destruction increases with the content of the catalyzer in solution and reaches a maximum value at a catalyzer concentration of < or = 3 g/l, after which it depends no longer on the catalyzer concentration. The flattening of the rate constant curve is caused by light scattering and the narrowing of the reaction scope due to an increase in the optical density of the solution. In the region where the rate constant increases with the catalyzer concentration, the rise in the rate constant is determined by an increase in the specific area of the catalyzer; in the region of the plateau, the rate constant is practically independent on the specific area of the catalyzer.

[Fluorescence quenching of chlorophyll and its analogs by oxidants]. / Nekotorye osobennosti tusheniia fluorestsii khlorofilla i ego analogov okisliteliami

The quenching of the fluorescence of chlorophyll, Zn- and Cd-pheophytinates, Mg-, Zn-, Cd-, Al-, Ga-, In-, Hf-tetraphenylporphine in different solvents with chlorinanyl, p-benzoquinone and m-dinitrobenzole has been studied. It is concluded from the dependence of quenching on medium viscosity that static and kinamatic mechanisms are in the basis of quenching. The first one dominates within the high values of viscosity, the latter within the law ones. In case of metals on one group the quenching constants are decreased with the growth of the ordinal number of the central atom. This fact supports the great role of the dynamic factor during the quenching of fluorescence of tetrapirrole pigments.