Nonlinear Brønsted and Hammett Correlations Associated with Reactions of 4-Chloro-7-nitrobenzofurazan with Anilines in Dimethyl Sulfoxide Solution
作者:I. Jmaoui、T. Boubaker、R. Goumont
DOI:10.1002/kin.20751
日期:2013.3
mechanism of nucleophilic aromatic substitution reactions of 4‐chloro‐7‐nitrobenzofurazan 1 with 4‐X‐substituted anilines 2a–g (X = OH, OCH3, CH3, H, I, Cl, and CN) are investigated in a dimethyl sulfoxide (Me2SO) solution at 25°C. The Hammett plot of log k1 versus σ is nonlinear for all the anilines studied due to positive deviations of the electron‐donating substituents. However, the corresponding Yukawa–Tsuno
研究了4-氯-7-硝基硝基苯并呋喃山1与4-X-取代苯胺2a-g(X = OH,OCH 3,CH 3,H,I,Cl和CN)的亲核芳香取代反应的动力学和机理。在25°C的二甲基亚砜(Me 2 SO)溶液中溶解。由于给电子取代基的正偏差,所有研究的苯胺的log k 1相对于σ的哈米特图都是非线性的。但是,相应的汤川-Tsuno图导致与σ+ r(σ + -σ)的良好线性相关。相应的布朗斯台德型情节也非线性的,即,斜率(β NUC)随着苯胺碱度的降低,从1.60变为0.56。这些结果表明,从极性较低的亲核试剂(X = I,Cl和CN)的极性S N Ar过程转变为碱性较高的亲核试剂(X = OH,OCH 3和CH 3)的单电子转移机理发生了变化。。在本系统中,1与苯胺2a–d的反应获得的令人满意的log k 1与E o的相关性与所提出的机理是一致的。有趣的是,β NUC = 1.60值测定1在我2SO反映了S