Sulphuryl chloride as an electrophile. Part 5. Chlorination of some anthracene derivatives; molecular orbital modelling of substituent effects
作者:Roger Bolton、D. Brynn Hibbert、Simin Parand
DOI:10.1039/p29860000981
日期:——
The rates of electrophilic attack at C-10 of some 9-substituted anthracenes (9-H, Br, CHO, CN, NO2, OMe, or Bz) by sulphuryl chloride have been measured (in PhCl 298 K). The substituent effects roughly parallel those expected from considering the simpler p-XC6H4 system (ρ–1.51; r 0.975); better agreement (ρ–1.23 ± 0.05; r 0.994) comes by using Dewar's FMMF treatment. MNDO calculations of the energy
已经测量了一些硫磺酰氯在C-10处对C的亲电进攻速率(9-H,Br,CHO,CN,NO 2,OMe或Bz)(在PhCl 298 K中)。取代基的影响大致与考虑使用更简单的p -XC 6 H 4体系(ρ-1.51;r 0.975)有关。通过使用杜瓦氏FMMF处理可获得更好的一致性(ρ–1.23±0.05; r 0.994)。MNDO对中间σ复合物的能量和最优化几何结构的MNDO计算显示出折叠结构,其允许一定程度的sp 3C-10原子的特征,同时在蒽离子中保持扩展的π系统足够的离域。遵循Bell-Eyring-Polyani原理,每种反应物与其σ络合物之间的计算能量差与Clδ +攻击过程中实验观察到的自由能变化之间存在线性关系。