PHOTOINDUCED ELECTRON-TRANSFER BETWEEN MOLECULES IN SILICA MATRICES

The reactions of electron transfer between anthracene (An), pyrene (Py ) and fluorescence quenchers N,N-dimethylaniline (DMA), N,N-diethylani line (DEA) and Cu2+ ions in heterogeneous systems on the basis of sili ca under the conditions of differing mobilities of molecules and chang es of carrier structure have been studied. Quenching of An and Py* by DEA and DMA on adsorption from hexane on the surface of pyrogenic non porous silica-aerosil is accompanied by exciplex formation and concent rational 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 s ystem. Intensity of Py fluorescence remains high and no quenching occu rs. Py molecules are encapsulated in the SiO2 between layers of hydrop hobic parts of TX-100. Photoinduced electron transfer between Py and CU2+ is effective at the stage of sol-gel transition in tetraethoxysil ane (TEOS) hydrolysis reaction. Py molecules trapped in porous sol-gel phases are shown to undergo photoinduced electron transfer with CU2when the liquid phase is present inside the pores.