HETEROASSOCIATION OF CAFFEINE AND PHENANTHRIDINONE DYE MOLECULES IN AQUEOUS SOLUTION

Abstract

Results of spectrophotometric research of the association of ethidium bromide and caffeine molecules in aqueous solution are presented. Experimental data were analyzed using a dimer model of heteroassociation of molecules. Numerical values of the equilibrium constants of association of molecules were defined. The experimental spectrum of absorption of a mixture of heterocyclic molecules was decomposed into individual components using the regularization method. Quantitative information on the heterocomplex structure based on the individual spectrum components was obtained - the distance and the angle between the point dipole moments of the transitions of heterogeneous molecules are 0.3 nm and 16°. Calculation of the relative content of different types of associates in a mixed solution shows that heteroassociation of molecules leads to a decrease in the effective concentration of ethidium bromide and, accordingly, to a lesser mutagenic activity of a dye.