Kushch Olga V, Hordieieva Iryna O, Kompanets Mykhailo O, Zosenko Olha O, Opeida Iosip A, Shendrik Alexander N
L.M. Litvinenko Institute of Physico-Organic Chemistry and Coal Chemistry, National Academy of Sciences of Ukraine, Kyiv 02660, Ukraine.
Faculty of Chemistry, Biology and Biotechnologies, Vasyl' Stus Donetsk National University, Vinnytsia 21021, Ukraine.
J Org Chem. 2021 Mar 5;86(5):3792-3799. doi: 10.1021/acs.joc.0c02595. Epub 2021 Feb 11.
A model for predicting the rate constants of hydrogen atom transfer (HAT) from the α-C-H bond of -substituted benzyl alcohols to -oxyl radicals was proposed. To quantify the factors governing the reactivity of both -oxyl radicals and benzyl alcohols, multivariate regression analysis was performed using various combinations of reactivity parameters. The analysis was based on a 2D array of 35 HAT reactions, the rate constants of which span 4 orders of magnitude. The proposed polyparameter equation approximates the experimental rate constants of reactions with high accuracy using three independent parameters: Brown and Okamoto's substituent constants σ in alcohol molecules and the spin population on O and N atoms in the N-O fragment of -oxyl radicals [calculated by DFT/B3LYP/6-31G(d,p)]. The rate constants of HAT reactions from -substituted benzyl alcohols to a series of aryl-substituted phthalimide--oxyl radicals containing either electron-withdrawing or electron-donating substituents (4-Cl, 4-HOOC, 4-CHO), quinolinimide--oxyl, benzotriazole--oxyl, and violuric acid radicals were experimentally determined at 30 °C in acetonitrile.
提出了一种预测从α-取代苄醇的α-C-H键向-氧基自由基转移氢原子（HAT）速率常数的模型。为了量化控制-氧基自由基和苄醇反应活性的因素，使用反应活性参数的各种组合进行了多元回归分析。该分析基于35个HAT反应的二维阵列，其速率常数跨越4个数量级。所提出的多参数方程使用三个独立参数高精度地近似反应的实验速率常数：醇分子中Brown和Okamoto的取代基常数σ以及-氧基自由基的N-O片段中O和N原子上的自旋布居[通过DFT/B3LYP/6-31G(d,p)计算]。在30℃下于乙腈中实验测定了从α-取代苄醇到一系列含有吸电子或供电子取代基（4-Cl、4-HOOC、4-CHO）的芳基取代邻苯二甲酰亚胺-氧基自由基、喹啉酰亚胺-氧基、苯并三唑-氧基和紫尿酸自由基的HAT反应的速率常数。
