Preparation, Characterization and photochemistry of 4,4diacetamidostilbene and its beta-cyclodextrin inclusion complex

The inclusion complex of trans-4,4'-diacetamidostilbene (1, DAST) with beta-cyclodextrin (2, DAST-CD) was prepared. The formation of the complex and its photochemical behaviour were investigated using a range of physical methods (H-1 and C-13 nuclear magnetic resonance (NMR) spectroscopy, fluorescence and absorption spectroscopy). The results indicate that a stable 1:1 inclusion complex is produced in the solid state and in methanol and dimethylsulphoxide. The guest molecule is completely encapsulated in the beta-cyclodextrin cavity. No difference in stability was observed between DAST and DAST-CD when the samples were irradiated by UV light in methanol. The photolysis products in dimethylsulphoxide were studied using H-1 NMR spectroscopy; the results indicate that the photolysis products are cis-DAST and 4,4'-diacetamidophenanthrene for DAST-CD, but cis-DAST only for DAST.