Studies on the interactions of 2,5-diphenyl 1,3,4-oxadiazole and 2,5-diphenyl 1,3-oxazole with β-cyclodextrin  

作　　者：ZHANG Chunfen, SHEN Xinghai and GAO Hongcheng(Institute of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China) 

出　　处：《Progress in Natural Science:Materials International》2002年第5期342-346,共5页自然科学进展·国际材料（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 29901001)

摘　　要：Interactions of 2,5-diphenyl 1,3,4-oxadiazole (PPD) and 2,5-diphenyl 1,3-oxazole (PPO) with β-cyclodextrin (β-CD) are studied by 1H-NMR and steady-state fluorescence measurements, and the stoichiometries and the association constants are estimated. It is found that the hydrophobic interaction is the main driving force for the formation of inclusion complexes of PPD and PPO with β-CD. In the presence of aliphatic alcohols (from 1-propanol to 1-pentanol), PPD and PPO transfer from the CD cavity to the aqueous phase. Quenching experiments of PPD and PPO by iodide further prove the above conclusions. The results suggest that stereo effect is the crucial factor to the inexistence of nanotube in PPD (or PPO)-β-CD systems.Interactions of 2, 5-diphenyl 1,3,4-oxadiazole (PPD) and 2, 5-diphenyl 1,3-oxazole (PPO) with β-cyclodextrin (β-CD) are studied by 1H-NMR and steady-state fluorescence measurements, and the stoichiometries and the association constants are estimated. It is found that the hydrophobic interaction is the main driving force for the formation of inclusion complexes of PPD and PPO with β-CD. In the presence of aliphatic alcohols (from 1-propanol to 1-pentanol), PPD and PPO transfer from the CD cavity to the aqueous phase. Quenching experiments of PPD and PPO by iodide further prove the above conclusions. The results suggest that stereo effect is the crucial factor to the inexistence of nanotube in PPD (or PPO)-β-CD systems.

关 键 词：1H-NMR  steady-state fluorescence  FLUORESCENCE anisotropy  β-cyclodextrin. 

分 类 号：O625[理学—有机化学]