LOW-TEMPERATURE STRUCTURAL FLUORESCENCE-SPECTRA OF TETRAHYDROXY-ANTHRAQUINONE ADSORBED ON SILICA

Adsorption of TOAQ on the surface of porous (silica gel) and non-porou s (aerosil) silica modification does not cause rupture of intramolecul ar hydrogen bonds (IMHB). The fine structure spectra of TOAQ fluoresce nce on silica gel contain a set of frequencies that are characteristic of weakly perturbed molecules. A number of new spectral effects appea r due to the existence of pores and centres of a nonhydroxyl character . Hydroxyl groups of aerosil take part in formation of intermolecular hydrogen bonding with the TOAQ C=O group. The bond energy of the four OH-groups of the TOAQ molecule changes non-uniformly, and the symmetry of an equilibrium nuclear configuration of TOAQ decreases.