Mechanical State Selection in Mechanochemical Bond Activation.
- 1ShanghaiTech University
Abstract
Mechanochemical reactivity provides a distinctive mode of energy input, wherein mechanical force performs work on molecular structures to access reactivity beyond conventional thermal activation. Yet a fundamental understanding of how transient mechanical impacts translate into productive molecular activation remains lacking, particularly under the stochastic conditions of ball milling. By promoting direct homolytic bond scission, mechanoradical chemistry provides an ideal platform to interrogate the role of mechanical force in triggering chemical reactions. However, the resulting highly reactive radical species are often short-lived and elusive, making their formation and reactivity difficult to quantify. Here we use a mechanoradical-chain C-S coupling reaction to amplify otherwise transient initiation events into a measurable kinetic response. Time-resolved kinetics reveal a pronounced force-dependent induction period, while theoretical calculations show that productive C-I homolysis requires a specific loading trajectory. These findings indicate that mechanical force does not simply promote bond cleavage in proportion to its magnitude; rather, individual impacts sample a distribution of mechanical states, with only a small subset being competent for chemical activation. This selective sampling of mechanically competent states provides a mechanistic basis that controls the initiation, propagation and extinction of mechanoradical chains, enabling sustained out-of-equilibrium radical reactivity under intermittent mechanical driving, including with otherwise inaccessible insoluble poly(disulfides) in a diffusion-limited setting.
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BibTeX
@misc{wang2026mechanical,
title = {{Mechanical State Selection in Mechanochemical Bond Activation.}},
author = {Taoyong Wang and Hao Li and Xuanyang Ni and KaKing Yan},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008988/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008988/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Mechanical State Selection in Mechanochemical Bond Activation.
AU - Taoyong Wang
AU - Hao Li
AU - Xuanyang Ni
AU - KaKing Yan
PY - 2026
DA - 2026/09/17
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008988/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008988/v1
AB - Mechanochemical reactivity provides a distinctive mode of energy input, wherein mechanical force performs work on molecular structures to access reactivity beyond conventional thermal activation. Yet a fundamental understanding of how transient mechanical impacts translate into productive molecular activation remains lacking, particularly under the stochastic conditions of ball milling. By promoting direct homolytic bond scission, mechanoradical chemistry provides an ideal platform to interrogate the role of mechanical force in triggering chemical reactions. However, the resulting highly reactive radical species are often short-lived and elusive, making their formation and reactivity difficult to quantify. Here we use a mechanoradical-chain C-S coupling reaction to amplify otherwise transient initiation events into a measurable kinetic response. Time-resolved kinetics reveal a pronounced force-dependent induction period, while theoretical calculations show that productive C-I homolysis requires a specific loading trajectory. These findings indicate that mechanical force does not simply promote bond cleavage in proportion to its magnitude; rather, individual impacts sample a distribution of mechanical states, with only a small subset being competent for chemical activation. This selective sampling of mechanically competent states provides a mechanistic basis that controls the initiation, propagation and extinction of mechanoradical chains, enabling sustained out-of-equilibrium radical reactivity under intermittent mechanical driving, including with otherwise inaccessible insoluble poly(disulfides) in a diffusion-limited setting.
ER -