纤维素纤维接枝β-环糊精对苯二酚类分子的包络识别性能

用分光光度滴定法在不同温度、不同pH值条件下测定了纤维素纤维接枝β-环糊精与苯二酚类分子形成超分子包合物的表观热力学参数. 化学计量法表明, 纤维素纤维接枝β-环糊精上环糊精与客体苯二酚类分子形成了1∶1的超分子包合物. 从主-客体间包合物的表观热力学参数、尺寸关系、溶液pH值、包合时间等因素讨论了纤维上环糊精对客体苯二酚类分子的分子识别机制. 结果表明, 纤维素纤维接枝β-环糊精上环糊精对苯二酚类分子不同位置羟基具有分子选择性和识别能力.

Molecular Inclusion Recognition of Dihydroxybenzenes by Cellulose Fibre Grated β-cyclodextrin

The complex stability constants for the 1∶1 inclusion complexation of various dihydroxybenzenes (pyrocatechol, hydroquinone, resorcinol) with cellulose fibre grafted β-cyclodextrin have been determined by means of spectrophotometric titrations at different temperatures in aqueous solutions with different pH values. The molecular recognition mechanism for various complexes of dihydroxybenzenes and β-cyclodextrin is discussed from the viewpoint of stability constants, apparent thermodynamic parameters, the size/shape-fit, multiple recognition, and pH value of inclusion systems of dihydroxybenzenes between the host cavity and the guest molecules. The results show that the cellulose fibre grafted β-cyclodextrin possesses a special binding ability and molecular selectivity for dihydroxybenzenes, the complex stability constants of dihydroxybenzenes are Ka(resorcinol)>Ka(hydroquinone)>Ka(pyrocatechol), apparent thermodynamic parameters of dihydroxybenzenes are ΔH(resorcinol )<ΔH(hydroquinone)<ΔH(pyrocatechol) and ΔS(resorcinol)<ΔS(hydroquinone)< ΔS(pyrocatechol).