Solvent hydrogen bonding and structural effects on the reaction of 2-halo-5-nitropyridines with parasubstituted anilines in dimethylsulfoxide/acetonitrile mixtures
作者:N. Kalaimani、S. Rathinam、D. S. Bhuvaneshwari
DOI:10.1002/kin.20558
日期:2011.8
both the substrates. The solvation model proposed is well supported by the solvatochromism exhibited by aniline in the solvent mixture under investigation. The molar extinction coefficient (εmax ) of aniline varies appreciably up to ∼25% with the change in composition of the mixture. The multivariate correlation analysis of εmax (with α, β, π*) suggests that the solvation around NH2 moiety of aniline
一些对位取代的苯胺与2-氯-5-硝基吡啶和2-溴-5-硝基吡啶的取代反应在二甲基亚砜/乙腈混合物中进行电导测定。二阶速率常数与Hammett取代基常数的相关性产生具有负斜率的相当线性的直线。在两种底物中,速率数据与Kamlet-Taft的溶剂变色参数之间的相关性极佳(100R 2 = 97%)。所提出的溶剂化模型得到了苯胺在所研究的溶剂混合物中表现出的溶剂化显色性的充分支持。苯胺的摩尔消光系数(εmax )随混合物组成的变化而变化约25%。εmax 的多元相关分析(具有α,β,π*)表明,通过氢键供体(HBD)性质在苯胺的NH 2部分周围的溶剂化在溶剂化过程中占主导地位,并因此改变了速率。观察结果是,通过溶剂混合物中苯胺的循环伏安氧化进一步证实了HBD在溶剂化中的优势。©2011 Wiley Peiodicals,Inc. Int J Chem Kinet 43:409-417,2011年