FTIR Spectroscopic Studies of Interactions of Stilbenes with Silicon Dioxide

K. E. Polunin, N. P. Sokolova, A. M. Gorbunov, R. A. Bulgakova, and I. A. Polunina

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,

Leninskii pr. 31, Moscow, 119991 Russia

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Received June 26, 2007

Abstract—Adsorption interactions of trans-stilbene and its hydroxy and methoxy derivatives with the surface of nanodispersed SiO₂ aerogel were studied by diffuse-reflection FTIR spectroscopy. Stilbenes were found to adsorb at the aerosil via hydrogen bonding to silanol OH groups. The deepest modification of these groups was produced by 3,5,4'-trihydroxystilbene (resveratrol). Although the stilbenes adsorbed reversibly, the absorption spectra of the starting and desorbed resveratrol proved to differ. UV irradiation ( = 285–305 nm) of adsorbed hydroxystilbenes changed the composition and properties of adsorbed layers. The changes include breaking of the hydrogen bonds between the hydroxystilbene molecules and the surface, destruction of the stilbenes involving cleavage of the double bond of the ethene fragment, dimerization, oxidation, and transformation into other compounds. The intensity of heterogeneous photolysis depends on the number and composition of functional groups in trans-stilbenes.

PACS numbers: 68.43.-h