超分子体系中的分子识别研究(一)——有机硒修饰β-环糊精的合成及其与L-和D-色氨酸的包结配位作用

Mpolecular Rexognigion Studies on Supram olecular Systems()——Syntheses of Organoselenium Modified β-Cyclodextrins and Their Inclusion Complexation with L- and D-Tryptophan

Mono（2-phenylseleno-2-deoxy）-β-cyclodextrin（2） and mono[2-（p-methoxyphenylseleno）-2-deoxy]-β-cyclodextrin（4）, were newly synthesized and characterized by combustion analyses, IR, 1H NMR and 13 C NMR. Spectrofluorometric titrations have been performed in aqueous phosphate buffer solution（pH 7.20, 0.1 mol/L） at 25 ℃ to give the complex K S and -ΔG° for the stoichiometric 1∶1 inclusion complexation of mono（6-phenylseleno-6-deoxy）-β-cyclodextrin（1）, mono[6-（p-methoxyphenylseleno）-6-deoxy]-β-cyclodextrin（3） and the novel cyclodextrin derivatives 2 and 4 with L- and D-tryptophan. The molecular binding ability and selectivity for L- and D-tryptophan of modified β-cyclodextrins（14） are discussed from the size/shape-fit and geometrical complement relationships between the host cavity and the guest molecule. The results obtained indicate that van der Waals force and hydrophobic interactions dominate the complexation of 1—4 and the aromatic substituents introduced extend the original hydrophobicity of cavity and the molecular binding ability, but reduce the enantioselectivity for L/D-tryptophan guests.