ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, NSW, 2052, Australia.
Data 61, Locked Bag 8001, Canberra, ACT, 2601, Australia.
Nat Commun. 2018 Apr 12;9(1):1436. doi: 10.1038/s41467-018-03860-2.
Despite being at the heart of chemical thought, the curly arrow notation of reaction mechanisms has been treated with suspicion-the connection with rigorous molecular quantum mechanics being unclear. The connection requires a view of the wavefunction that goes beyond molecular orbitals and rests on the most fundamental property of electrons. The antisymmetry of electronic wavefunctions requires that an N-electron wavefunction repeat itself in 3N dimensions, thus exhibiting tiles. Inspection of wavefunction tiles permits insight into structure and mechanism. Here, we demonstrate that analysis of the wavefunction tile along a reaction coordinate reveals the electron movements depicted by the curly arrow notation for several reactions. The Diels-Alder reaction is revealed to involve the separation and counter propagation of electron spins. This unprecedented method of extracting the movements of electrons during a chemical reaction is a breakthrough in connecting traditional depictions of chemical mechanism with state-of-the-art quantum chemical calculations.
尽管处于化学思维的核心，但反应机制的弯箭头符号一直受到怀疑——与严格的分子量子力学之间的联系尚不清楚。这种联系需要一种超越分子轨道的波函数观点，并基于电子最基本的性质。电子波函数的反对称性要求 N 电子波函数在 3N 维空间中自我重复，从而表现出平铺。对波函数平铺的检查可以深入了解结构和机制。在这里，我们证明了沿反应坐标分析波函数平铺可以揭示弯箭头符号表示的几个反应中的电子运动。Diels-Alder 反应涉及电子自旋的分离和反向传播。这种在化学反应中提取电子运动的前所未有的方法是将传统的化学机制描述与最先进的量子化学计算联系起来的突破。
