Andrés Juan, González-Navarrete Patricio, Safont Vicent Sixte, Silvi Bernard
Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castelló, Spain.
Phys Chem Chem Phys. 2017 Nov 8;19(43):29031-29046. doi: 10.1039/c7cp06108k.
Despite the usefulness of curly arrows in chemistry, their relationship with real electron density flows is still imprecise, and even their direct connection to quantum chemistry is still controversial. The paradigmatic description - from first principles - of the mechanistic aspects of a given chemical process is based mainly on the relative energies and geometrical changes at the stationary points of the potential energy surface along the reaction pathway; however, it is not sufficient to describe chemical systems in terms of bonding aspects. Probing the electron density distribution during a chemical reaction can provide important insights, enabling us to understand and control chemical reactions. This aim has required an extension of the relationships between the concepts of traditional chemistry and those of quantum mechanics. Bonding evolution theory (BET), which combines the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT), provides a powerful method that offers insight into the molecular mechanism of chemical rearrangements. In agreement with the laws of physical and aspects of quantum theory, BET can be considered an appropriate tool to tackle chemical reactivity with a wide range of possible applications. In this work, BET is applied to address a long-standing problem: the ability to monitor the flow of electron density. BET analysis shows a connection between quantum mechanics and bond making/forming processes. Likewise, the present approach retrieves the classical curly arrows used to describe the rearrangements of chemical bonds and provides detailed physical grounds for this type of representation. We demonstrate this procedure using the test set of prototypical examples of thermal ring apertures, and the degenerated Cope rearrangement of semibullvalene.
尽管弯箭头在化学中很有用，但它们与实际电子密度流动的关系仍然不精确，甚至它们与量子化学的直接联系也仍存在争议。从第一原理对给定化学过程的机理方面进行的典型描述主要基于势能面沿反应路径的驻点处的相对能量和几何变化；然而，仅从键合方面来描述化学体系是不够的。探测化学反应过程中的电子密度分布可以提供重要的见解，使我们能够理解和控制化学反应。这一目标需要扩展传统化学概念与量子力学概念之间的关系。键合演化理论（BET）结合了电子定域函数（ELF）的拓扑分析和托姆突变理论（CT），提供了一种强大的方法，可深入了解化学重排的分子机制。与物理定律和量子理论的各方面相一致，BET可被视为一种适用于解决化学反应性问题的工具，具有广泛的可能应用。在这项工作中，BET被用于解决一个长期存在的问题：监测电子密度流动的能力。BET分析显示了量子力学与键的形成/断裂过程之间的联系。同样，本方法找回了用于描述化学键重排的经典弯箭头，并为这种表示形式提供了详细的物理依据。我们使用热环开环的典型示例测试集以及半环戊二烯的退化科普重排来演示此过程。
