Special features of absorption and fluorescence spectra of immunoactive 8-azasteroids

Biologically active molecules of 8-azagon-12,17-dion fluoresce in solvents of various natures, in the crystalline phase, and under conditions of high-temperature vapor. Characteristics of absorption and fluorescence of these molecules in aprotic acetonitrile are studied in detail. Absorption observed in the region of 250-400 nm is associated with transitions of the types pi --> pi* and n --> pi*. Fluorescence excitation spectra demonstrated dependence of emission detected on the wavelength. Experimental data are analyzed within the framework of concepts of the multicentered nature of molecular systems on the basis of the model of electronic mesomeric tautomerism. (C) 2001 MAIK "Nauka/Interperiodica".