Xu Fangzhou, Zhu Jun
State Key Laboratory of Physical Chemistry of Solid Surfaces and, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.
Chemistry. 2023 Feb 7;29(8):e202203216. doi: 10.1002/chem.202203216. Epub 2022 Dec 19.
The oxidative addition of C-C bonds in aromatic hydrocarbons by low valent main group species has attracted considerable attention from both theoretical and experimental chemists due to the big challenge in breaking their aromaticity. Herein, a general strategy to break the C-C bonds in benzene by cyclic (alkyl)(amino)aluminyl anion is demonstrated via density functional theory (DFT) calculations. The results suggest that the activation of the C-C bond of benzene by this anion is both kinetically and thermodynamically unfavorable whereas introducing electron-withdrawing groups makes such C-C bond activation becomes favorable both kinetically and thermodynamically. Such a sharp change on the kinetics and thermodynamics could be rationalized by the frontier molecular orbital theory by decreasing the lowest unoccupied molecular orbitals of the mono- and disubstituted benzenes. Aromaticity is found to stabilize the transition state for the ring open step. All these findings can help develop the chemistry of small-molecule activation.
由于破坏芳烃的芳香性面临巨大挑战，低价主族物种对芳烃中碳 - 碳键的氧化加成引起了理论化学家和实验化学家的广泛关注。在此，通过密度泛函理论（DFT）计算证明了一种通过环（烷基）（氨基）铝阴离子断裂苯中碳 - 碳键的通用策略。结果表明，该阴离子对苯碳 - 碳键的活化在动力学和热力学上都是不利的，而引入吸电子基团会使这种碳 - 碳键活化在动力学和热力学上都变得有利。动力学和热力学上的这种急剧变化可以通过前沿分子轨道理论来解释，即通过降低单取代和二取代苯的最低未占据分子轨道。发现芳香性稳定了开环步骤的过渡态。所有这些发现有助于发展小分子活化化学。
