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在碱性介质中,用传统的分光光度法研究了Ag(III)配离子,即[Ag(HIO6)2]5-,氧化药物分子愈创甘油醚的动力学及其机理.用质谱鉴定了氧化产物;反应对Ag(III)和愈创甘油醚均为一级;在温度25.0-40.0℃范围内,通过分析[OH-]和[IO4-]tot对反应速率的影响,二级速率常数有以下表达式:k′=(ka+kb[OH-])K1/｛f([OH-])[IO4-]tot+K1｝,在25.0℃及离子强度0.30mol·L-1时,对此反应有ka=(2.6±1.2)×10-2mol-1·L·s-1,kb=(2.8±0.1)mol-2·L2·s-1,及K1=(4.1±0.4)×10-4mol·L-1,求出了涉及ka,kb的活化参数,并据此推出反应机理为反应体系中的[Ag(HIO6)2]5-配离子在前期平衡后,反应活性中心与药物分子形成Ag(III)-过碘酸-愈创甘油醚分子三元配合物,配位甘油醚分子通过两个平行途径将两电子传递给中心原子Ag:一个途径无OH-离子参与,另一途径有OH-参与完成.
The kinetics and mechanism of Ag (HIO6) 2] 5-, an oxidized drug molecule, guaifenesin, were studied by using conventional spectrophotometry in alkaline media. Mass spectrometry was used to identify The oxidation rate of Ag (III) and guaifenesin were all in the first order. By analyzing the influence of [OH-] and [IO4-] tot on the reaction rate in the range of 25.0-40.0 ℃, the second order rate constant Has the following expression: K ’= (ka + kb [OH -]) K1 / {f ([OH -]) [IO4-] tot + K1} at 25.0 ° C and an ionic strength of 0.30 mol·L-1, The response was ka = (2.6 ± 1.2) × 10-2 mol-1 · L · s-1, kb = (2.8 ± 0.1) mol-2 · L2 · s-1 and K1 = (4.1 ± 0.4) × 10-4mol·L-1, we got the activation parameters related to ka and kb, and deduced the reaction mechanism as follows: the reaction center of [Ag (HIO6) 2] 5- The drug molecules form Ag (III) -periodo-guaifenesin ternary complex, and the glyceryl ether molecules transfer the two electrons to the central atom Ag through two parallel routes: one route has no OH-ion involved, and the other One way to get OH-participation done.