Studies On Molecular Recognition In Terms Of A Characteristic Index

Selective intermolecular interactions of the three hosts, such as poly ethylene glcol (PEG), dibenzyl-24-crown-8 (DB24C8) and β-cyclodextrin (β-CD), with 26 guest compounds have been studied using major thermodynamic strategy. The main works in the present article fall into four parts, and are summarized as follows:In the first part, the solution thermodynamic properties for neutral organic compounds in PEG GC stationary liquid phase have been measured by means of gas-liquid chromatography. Based on the compensatory ' enthalpy-entropy relationship, a characteristic parameter for evaluating the fitness of a solute to the structure of PEG was proposed and introduced. Then, in the light of molecular recognition or selective intermolecular interaction, we discuss and analyze the dependence of thermodynamic behavior on intermolecular noncovalent interactions existing in solute-PEG systems.In the second part, the effects of flexibility of PEG structure on complexation between PEG and neutral organic solutes have been examined using GLC method, where PEG of low molecular weight (PEG-1000) was used as GC stationary liquid phase. It is found that at least two different recognition patterns exist in retention in PEG-1000. One is.linear recognition pattern, in which the interaction results from noncyclie-arranged sites of the macromolecule and...