摘要
采用紫外光谱法研究β-环糊精(B-CD)、羧甲基-阻环糊精(CM-B-CD)和部分甲基化-β-环糊精(PM-G-CD)对2,4-滴丙酸甲酯包合作用的对映体差异.在298.15~318.15K的温度范围内,3种环糊精均能与2,4-滴丙酸甲酯形成1:1型的包合物,其包合常数值大小依次为KPM-β-CD》KcM-β-CD,且随着温度的升高而降低.经计算,热力学参数△G、△H和△S均为负值,说明包合反应是放热反应且能自发进行,焓变是形成包合物的主要驱动力.对于同-环糊精主体而言,R-2,4-滴丙酸甲酯比S-2,4-滴丙酸甲酯易于被包合,且KR/KS的顺序与包合常数K值的次序-致.
The enantioselective inclusion interaction of various cyclodextrins (β-CD, PM-β-CD, CM-β- CD) with R/S-2,4-dichlorprop methyl ester (R/S-2,4-D) was studied by UV spectra technique. The results show that all cyclodextrins formed 1 : 1 inclusion complexes with 2,4-D, the order of binding constants of three types cyclodextrins and 2,4-D was KpM-CD〉〉 KCMM-β-CD〉Kβ-CD Between 298.15 K and 318. 15 K, the binding constants decreased as the temperature increased. All Gibbs free energy AG, enthalpy change △H, and entropy change AS determined were negative, suggesting that the inclusion interaction was exothermic and spontaneously occurred by balance of enthalpy driven and entropy opposed. R-2,4-D was easier enclosed than S-2,4-D by the same kind of cyclodextrins and the order of KR/Ks was accordance with the order of binding constants.
出处
《浙江大学学报(农业与生命科学版)》
CAS
CSCD
北大核心
2008年第1期50-56,共7页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
国家自然科学基金资助项目(20677049)
关键词
环糊精
2
4-滴丙酸甲酯
包合作用
紫外光谱
cyclodextrins
2,4-dichlorprop methyl ester
inclusion interaction
UV spectra