摘要
用PM3半经验方法优化了 5种不同含氮基团修饰环糊精的结构 ,并用HF方法在STO 3G和 3 2 1G 两种基组水平上计算了它们的单点能 .首次给出了这 5种修饰环糊精的优化结构 ,同时计算结果采用极性基团会增加修饰环糊精的偶极距 ,优化的结构及计算出的物理性质表明修饰后产物明显与 β 环糊精有明显的差别 .
Cyclodextrins(CDs) are cyclic oligomers of D-glueose and named α-,β-, γ-CD for hexamer, heptamer and octamer, respectively. Owing to its special structural character, they formed inclusion complexes with various types of organic molcules in aqueous solution and attracted the curiosity of chemists and biologists since they could be regarded as artificial receptors. Some cyclodextrin molecules were modified with functional groups in order to improve the properties in complexation and catalysis. The present parper report the quantum chemistry studies on 5 nitrogen containing group modified β-cyclodextrins. The results of geometry optimization showed that the location of modified functional group in molecular structure is vastly influenced by its volume. The physicochemical information was obtained by single point energy calculations. This heuristic calculation can also be used as a predicted method for new synthesis of modified cyclodextrins. The computational chemistry is therefore both an independent research tool and a vital adjunct to cyclodextrin experimental studies.
基金
国家自然科学基金资助项目 (2 98730 6 2 )~~
