Kinetic Study on the Interactions of Cyclodextrins with Organic Phosphates and Thiophosphates
作者:Takuya Nagata、Kenta Yamamoto、Keisuke Yoshikiyo、Yoshihisa Matsui、Tatsuyuki Yamamoto
DOI:10.1246/bcsj.82.76
日期:2009.1.15
α-Cyclodextrin (α-CD) and 6-O-α-d-glucopyranosyl-β-cyclodextrin (G1-β-CD) affected the rates of phenol release from a few dimethyl(nitrophenyl) phosphates and the corresponding thiophosphates in aqueous alkaline solutions. Curve-fitting analysis of changes in the rate constants with CD concentrations showed that both α-CD and G1-β-CD form not only 1:1 but also 2:1 (host:guest) complexes with the phosphates and thiophosphates. In 1:1 complexes, phenol release from the phosphates was mostly accelerated, and that from the thiophosphates was decelerated. In 2:1 complexes, the reactions both of the phosphates and thiophosphates were strongly retarded. Binding constants and rate constants determined showed significant host and substrate specificities.
α-环糊精(α-CD)和6-O-α-D-吡喃葡萄糖基-β-环糊精(G1-β-CD)影响了几种二甲基(硝基苯基)磷酸酯及其相应硫代磷酸酯在水性碱性溶液中的苯酚释放速率。通过对随CD浓度变化的速率常数进行曲线拟合分析,结果表明α-CD和G1-β-CD与磷酸酯和硫代磷酸酯不仅形成了1:1的复合物,还形成了2:1(主体:客体)的复合物。在1:1复合物中,磷酸酯的苯酚释放大多被加速,而硫代磷酸酯的苯酚释放则被减速。在2:1复合物中,磷酸酯和硫代磷酸酯的反应均被显著延缓。确定的结合常数和速率常数显示了显著的主客体和底物特异性。