Kinetics and Mechanism of the Pyridinolysis of Dimethyl Isothiocyanophosphate in Acetonitrile
作者:Keshab Kumar Adhikary、Hai-Whang Lee
DOI:10.5012/bkcs.2012.33.7.2260
日期:2012.7.20
The kinetics and mechanism of the pyridinolysis () of dimethyl isothiocyanophosphate are investigated in acetonitrile at . The Hammett and Brnsted plots for substituent X variations in the nucleophiles exhibit two discrete slopes with a break region between X = 3-Ac and 4-Ac. These are interpreted to indicate a mechanistic change at the break region from a concerted to a stepwise mechanism with a rate-limiting
在乙腈中研究了二甲基异硫氰基磷酸酯吡啶解 () 的动力学和机理。亲核试剂中取代基 X 变化的 Hammett 和 Brnsted 图表现出两个离散的斜率,在 X = 3-Ac 和 4-Ac 之间有一个断裂区域。这些被解释为表明断裂区域的机械变化从协同机制到逐步机制,其中异硫氰酸酯离去基团从中间体中的限速排出。相对较大的值意味着正面亲核攻击 TSf 的比例远大于背面攻击 TSb 的比例。两种配体的空间效应对确定异硫氰基磷酸盐的吡啶解速率起着重要作用。
Pyridinolysis of Dipropyl Chlorophosphate in Acetonitrile
作者:Md. Ehtesham Ul Hoque、Hai-Whang Lee
DOI:10.5012/bkcs.2012.33.10.3441
日期:2012.10.20
Pyridinolysis of Dibutyl Chlorophosphate in Acetonitrile