摘要
农药通过与环糊精形成主客体包合物,可使其理化性质得到明显改善,因此研究环糊精对农药分子的识别作用具有重要的理论和实际意义。采用紫外-可见吸收光谱法研究了β-环糊精(β-CD),甲基-β-环糊精(RAMEB),羟丙基-β-环糊精(HP-β-CD)对杀菌剂醚菌酯的分子识别作用,并考察了温度及溶剂的极性对识别作用的影响,探讨了包合过程的驱动力和形成的包合物的可能结构。结果表明,他们与醚菌酯均可形成1∶1型包合物,在298.15K时,其结合常数值大小依次是KHP-β-CD>Kβ-CD>KRAMEB,随着温度的升高,包合物的稳定性逐渐降低,在温度≥303.15K时,Kβ-CD值最大。溶剂极性的改变可显著地影响结合常数值,随着溶剂极性的降低,结合常数值迅速降低。对包合物形成过程的热力学参数计算表明包合过程是一个自发的、放热的、体系自由能减少的过程。包合过程是焓驱动的,符合熵焓互补原则,推测氢键和疏水作用是识别反应的主要驱动力。本文研究结果为醚菌酯-β-环糊精包合物的应用提供了重要的信息。
The molecular recognition of fungicide of kresoxim-methyl with β-cyclodextrin （β-CD） , methyl-β-cyclodextrin （RAMEB）and hydroxypropyl-β-cyclodextrin（RAMEB） was investigated by using UV-Vis spectroscopy analysis. The effect of temperature and polarity of solvent on the recognition interaction was studied. The driving force and the possible structure of the inclusion complexes were also discussed. The results presented that they formed inclusion complexes with a stoichiometry of 1 ： 1, and the formation constant of inclusion complexes was in the order of KHP-β-CD〉Kβ-CD〉KRAMEB at 298. 15 K. Elevation of the temperature triggered a decrease in stability of the inclusion complexes and the value of Kβ-CD was the biggest at 9303. 15 K. The formation constant reduced sharply with the decreasing polarity of the solvent. The standard molar Gibbs energies, enthalpies and entropies were all negative, All the results indicated that the association of the guest molecule with β-CD was favored by enthalpy changes, and hydrophobicity and hydrogen bond interaction were main driving forces for the inclusion reaction. Our findings provided an important proof for the use of inclusion complexes of kresoxim-methyl with CDs.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2008年第10期2370-2374,共5页
Spectroscopy and Spectral Analysis
基金
国家"十一五"科技支撑计划项目(2006BAE01A03-10)资助
关键词
v环糊精
醚菌酯
分子识别
包合物
光谱分析
β-Cyclodextrin
Kresoxim-Methyl
Molecular recognition
Inclusion complex
Spectroscopic analysis
