The crosspropagation of 1-ethylcyclopentyl methacrylate (ECPMA) and methyl methacrylate (MMA) has been studied using a combination of quantum chemistry calculations and experiment. Our computational work utilizes a trimer-to-tetramer reaction model, coupled with an ONIOM (B3LYP/6-31G(2df,p): B3LYP/6-31G(d)) method for geometry optimization and an M06-2X/6-311+G(2df,p) method plus SMD solvation model for single point energy calculations. The results show several trends: the identity of the ultimate unit of a trimer radical affects not only the preferred conformation of the region where the reaction takes place, but also the reactivity of the radical; the addition of an ECPMA monomer to the radicals is generally favored compared to an MMA monomer; the pen-penultimate unit of a trimer radical shows a nonnegligible entropic effect; the penultimate unit effect is implicit for the ECPMA–MMA copolymer system. Finally, terminal model reactivity ratios fitted based on the explicit rate coefficients calculated from the quantum chemical results are compared with those from experimental measurements. The computations not only agree qualitatively with experimentally derived results in terms of the selectivity of ECPMA–MMA crosspropagation, but also give reasonable quantitative predictions of reactivity ratios.

中文翻译：

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1-乙基环戊基甲基丙烯酸酯和甲基丙烯酸甲酯共​​聚传播动力学的联合计算和实验研究

结合量子化学计算和实验研究了 1-乙基环戊基甲基丙烯酸酯 (ECPMA) 和甲基丙烯酸甲酯 (MMA) 的交叉传播。我们的计算工作利用三聚体到四聚体反应模型，结合用于几何优化的 ONIOM (B3LYP/6-31G(2df,p): B3LYP/6-31G(d)) 方法和 M06-2X/6- 311+G(2df,p) 方法加上用于单点能量计算的 SMD 溶剂化模型。结果显示了几个趋势：三聚体自由基最终单元的特性不仅影响反应发生区域的优选构象，而且影响自由基的反应性；与 MMA 单体相比，通常有利于将 ECPMA 单体添加到自由基中；三聚体自由基的倒数第二个单元显示出不可忽略的熵效应；ECPMA-MMA 共聚物体系的倒数第二个单元效应是隐含的。最后，将基于量子化学结果计算的显式速率系数拟合的终端模型反应性比率与实验测量的结果进行比较。计算不仅在 ECPMA-MMA 交叉传播的选择性方面与实验得出的结果定性一致，而且还给出了反应性比率的合理定量预测。