The reactions of electron transfer between anthracene (An), pyrene (Py) and fluorescence quenchers N,N-dimethylaniline (DMA), N,N-diethylaniline (DEA) and Cu²⁺ ions in heterogeneous systems on the basis of silica under the conditions of differing mobilities of molecules and changes of carrier structure have been studied. Quenching of An* and Py* by DEA and DMA on adsorption from hexane on the surface of pyrogenic nonporous silica-aerosil is accompanied by exciplex formation and concentrational dependence of the rate constant of quenching. Fluorescence of solubilized Py is quenched very strongly by adding DMA in adsorbed TX-100 micelles. Removal of water sharply changes the photonics of the system. Intensity of Py fluorescence remains high and no quenching occurs. Py molecules are encapsulated in the SiO₂ between layers of hydrophobic parts of TX-100. Photoinduced electron transfer between Py* and Cu²⁺ is effective at the stage of sol-gel transition in tetraethoxysilane (TEOS) hydrolysis reaction. Py molecules trapped in porous sol-gel phases are shown to undergo photoinduced electron transfer with Cu²⁺ when the liquid phase is present inside the pores.

Stability of vitamin D₃ on aerosil surfaces has been studied by UV- and IR-spectroscopy. The difference in the thermobehaviour of vitamin D₃ in the adsorbed state at low and high surface coverages has been observed and discussed in terms of the competition between vitamin D₃ molecules and their thermoisomers for the adsorption sites.