Mechanochemistry Activated by Confinement- and Shear-Induced Molecular Distortion

Mechanochemical activation occurs through the direct coupling of mechanical force with a chemical reaction coordinate, distorting reactant molecules from their equilibrium geometries. Understanding how this distortion reshapes the potential energy surface and, more importantly, connecting that understanding to experimentally measured mechanochemical reaction rates is a significant and inherently multiscale challenge. In this review, we first introduce the theoretical framework for defining the reaction coordinate and how it changes due to applied force. We then summarize previous studies that used experiments, molecular dynamics simulations, and quantum chemical calculations to explore mechanochemical activation in the context of confinement- and shear-induced molecular distortion. Experiments yield macroscopic activation parameters, molecular dynamics simulations capture bulk deformation and the local distortion of molecules, and quantum methods resolve electronic-structure and energy changes. Each approach offers unique insights but also has intrinsic limitations. We therefore advocate integrated multiscale strategies that couple experiments, continuum modeling, reactive molecular dynamics, and quantum mechanochemistry. Such strategies can bridge controllable macroscopic inputs with force-induced changes to the reaction coordinate, ultimately enabling predictive design rules for mechanochemical systems.