Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
Phys Chem Chem Phys. 2019 Apr 3;21(14):7378-7388. doi: 10.1039/c8cp07349j.
In molecular mechanochemistry, the chemical properties of a reactant system are modified through the absorption of mechanical energy at the single molecular level, as opposed to thermochemistry (heat), electrochemistry (electrical current) and photochemistry (light). In this proof-of-concept paper, we present a theoretical approach to rationalize and predict the change in chemical properties and concepts when an external stretching force, Fext, is applied to a chemical bond. By considering perturbations to the total molecular energy due to Fext, a series of mechanochemical response indices are obtained within the framework of conceptual density functional theory (DFT). Trends in these indices monitoring the change in hardness and electrophilicity among others, were rationalized for a number of diatomic molecules in terms of the ground-state geometry and the frontier molecular orbitals of the molecule. Finally, we present a set of rules that can be easily adopted for polyatomic molecules to predict the changing chemical reactivity of single molecules when subjected to an external force.
在分子机械化学中，通过在单分子水平上吸收机械能来修饰反应物系统的化学性质，而不是通过热化学（热量）、电化学（电流）和光化学（光）。在这篇概念验证论文中，我们提出了一种理论方法，可以合理化和预测当外部拉伸力 Fext 施加到化学键上时化学性质和概念的变化。通过考虑由于 Fext 引起的总分子能量的微扰，在概念密度泛函理论（DFT）的框架内获得了一系列机械化学响应指数。这些指数监测硬度和亲电性等变化的趋势，根据分子的基态几何形状和前沿分子轨道，对许多双原子分子进行了合理化。最后，我们提出了一组规则，这些规则可以很容易地应用于多原子分子，以预测当分子受到外力时单个分子化学反应性的变化。
