Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland.
J Comput Chem. 2023 Jun 5;44(15):1454-1463. doi: 10.1002/jcc.27104. Epub 2023 Mar 10.
Quantum-chemical calculations were used to describe both the acidity of aluminabenzene-based Lewis acids and stability of aluminabenzene-based anions. Aluminabenzene itself was found to exhibit greater acidity than antimony pentaflouride, and thus can be qualified as a Lewis superacid. Substitution of the heterocyclic ring with electron withdrawing groups results in formation of extremely strong Lewis superacids. Two of them, namely AlC Cl and AlC (CN) are the strongest Lewis acids described in the literature so far. Whereas, anions formed after the addition of fluoride anion to substituted aluminabenzene-based Lewis acids, while characterized by somewhat lower electronic stability than the least coordinating anions hitherto known, are considerably more stable in terms of thermodynamic stability (measured by the propensity to electrophile attack). On this account they are expected to act as counterions for the most reactive cations. The proposed Lewis acids may be prone to the isomerization and dimerization, whereas studied anions are expected to be stable with regard to such processes.
量子化学计算用于描述基于铝苯的路易斯酸的酸度和基于铝苯的阴离子的稳定性。发现铝苯本身的酸性大于五氟化锑，因此可以被定性为路易斯超强酸。用吸电子基团取代杂环会形成极强的路易斯超强酸。其中两种，即 AlC Cl 和 AlC（CN），是迄今为止文献中描述的最强路易斯酸。然而，取代的基于铝苯的路易斯酸与氟阴离子加成后形成的阴离子，尽管其电子稳定性略低于迄今为止已知的最配位阴离子，但在热力学稳定性（通过亲电攻击的倾向来衡量）方面要稳定得多。因此，它们有望作为最活泼阳离子的抗衡离子。所提出的路易斯酸可能容易发生异构化和二聚化，而研究中的阴离子预计在这些过程中是稳定的。
