Starukh G. Photonics of organic fluorofores on the titania-silica surfaces

Object: pecularities of the processes of the intra- and intermolecular photoinduced electron transfer in molecules with different donor-acceptor properties adsorbed on the surface of the titania-silica composites. The important role of the absorption of molecules under investigation on titania-silica surface in inter- and intramolecular electron transfer processes has been revealed. Decrease of fluorescence intensity of the excited pyrene and anthracene occurs on the titania-silica surfaces and clearly shows a dependence on titania content. The fluorescence quenching occurs as a result of electron transfer from excited adsorbed molecule to titanium ions or titania particles incorporated in silica. Titania-silica surface strongly effects on the mechanism of bimolecular diffusion-controlled reaction between anthracene and tertiary amine. Instead of exciplex formation (typically for the solutions) competitive adsorotion of amine and acene on the active "titania" center occurred. The photoinduced twist-intramolecular electron transfer within pyrazolopyridine derivative is inhibited due to adsorption of this TICT molecule on silica and titania-silica colloid surfaces. It has been established that pyrene fluorescence intensity is not effected by titania in presence of b-cyclodextrin in the titania-silica media due to formation of inclusion complexes. Titania-silica composites demonstrate hight photocatalytic activity in the process of mineralization of textile dye Methylene Blue in water solutions.