TY  - THES
T1  - Enhanced aqueous solubility and photodimerization of polycyclic aromatics mediated by γ-Cyclodextrin derivatives
A1  - Wang,Hai Ming
Y1  - 2012/04/24
N2  - A series of hydrophilic γ-cyclodextrin (CD) thioethers were synthesized and selected as hosts. They were able to solubilize polycyclic aromatic guests in water to much higher extents than native CDs. The results of experimental (phase-solubility method and fluorescence spectroscopy) and theoretical (quantum mechanical and space-filling calculations) investigations confirmed the formation of 1:2 CD-guest complexes in aqueous solution. True molecular solutions of C60 were obtained by dissolving C60 in aqueous solutions of γ-CD thioethers and confirmed by using dynamic light scattering method. We also succeed to obtain stable aqueous dispersions of C60, by employing the methods based on solvent exchange in presence of γ-CD thioethers. γ-CD thioether acted as a supramolecular catalytic nano-reaction vessel and facilitates the photodimerization of the aromatic guests in aqueous medium. High quantum yields of the photodimerizations in presence of γ-CD thioethers were obtained when compared to those of the aromatic guests in host-free solutions. The orientation of two molecules of acenaphthylene when bound to CD led to the selective formation of the trans product upon irradiation in quantitative yield for the first time. Excitation of the 1:2 CD–guest inclusion complex of coumarin in water resulted in an increased yield of syn head-to-head dimer. Other photoproducts of coumarin which typically produced in the absence of the template were remarkably suppressed by salting out effect.
KW  - Cyclodextrin
KW  - Solubilisation
KW  - Polycyclische Aromaten
CY  - Saarbrücken
PB  - Universitäts- und Landesbibliothek
AD  - Postfach 151141, 66041 Saarbrücken
UR  - http://scidok.sulb.uni-saarland.de/volltexte/2012/4834
ER  -