Binding forces in complexation of p -alkylphenols with β -cyclodextrin and methylated β -cyclodextrins

摘要: Fluorescence spectroscopy has been used to determine the binding constants (K) for inclusion complexes of six kinds ofp-Akyphenols withβ-cyclodextrin (β-CDx), heptakis(2,6-di-O-methyl)-β-CDx (DMe-β-CDxg), and heptakis(2,3,6-tri-O-methyl)-β-CDx (TMe-β-CDx). The stability complex each cyclodextrin increases with increasing alkyl chain length thep-alkylphenol. TheK values decrease in order DMe-β-CDx,β-CDx, TMe-β-CDx guest. In complexation 3-(p-hydroxyphenyl)-1-propanol (3) withβ-CDx as well DMe-β-CDx, negative enthalpy (ΔH) positive entropy changes (ΔS) have obtained, suggesting both van der Waals hydrophobic interactions forces. 3 by TMe-β-CDx, however, is an enthalpically favorable but entropically unfavorable process. may be main forces complexing3 TMe-β-CDx.