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基于芳香性的循环他基超和超酸的合理设计

Mrinal Kanti Si¹, Yasuteru Shigeta¹

¹Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8577, Japan.

The journal of physical chemistry. A

|August 22, 2024

概括

研究人员使用替代环二烯衍生物设计了新的有机超酸. 这些化合物表现出过酸性,超过硫酸,由于其无质子形式的增强芳香性和结合性.

科学领域:

有机化学有机化学
计算化学的计算化学
酸化学酸化学是指酸与酸之间的关系.

背景情况:

中性有机超酸在各种化学应用中至关重要,包括聚合和离子分离.
环二烯是一种温和的有机酸;稳定其基可以增强酸度.
探索了环二烯的芳香替代剂,以实现超酸和超酸性质.

研究的目的:

设计和合成基于替代环二烯的新型中性有机超酸.
为了研究结构修饰 (和替代物) 和酸度之间的关系.
评估这些化合物表现出超酸性和超酸性行为的潜力.

主要方法:

采用了计算方法,包括MP2,DFT (B3LYP,M06-2X) 和CBS-QB3,以计算气相质子亲缘关系.
使用了密度函数理论 (DFT) 方法,根据环二烯的实验数据进行了验证.
使用核独立化学转移 (NICS) 和和振荡器芳香度模型 (HOMA) 评估环二烯离子的芳香度和结合.

主要成果:

三位置换的环二烯衍生物显示出过酸性,气相脱 (ΔHacid) 的热量为245和239kcal/mol (DFT B3LYP和M06-2X).
一些体表现出过酸性,质子亲和度值在205-240 kcal/mol之间.
用三基替代的环二烯在用基替换基后转化为超酸 (ΔHacid = 298 kcal/mol),超过了硫酸的酸度.

结论:

脱后环二烯衍生物中增加的芳香性和合性显著提高了基的稳定性及其酸度.
设计的替代环二烯显示出对先进化学应用的强效超酸和超酸的潜力.
计算建模提供了一种可靠的方法来预测和设计具有量身定制属性的有机超酸.

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