The activation efficiency of mechanophores can be modulated by adjacent polymer composition

Kumar, Sourabh; Stauch, Tim

doi:10.1039/d0ra09834e

Cited by 9 publications

(7 citation statements)

References 42 publications

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“…In the future, however, we plan to apply a significantly refined QM/MM model that takes into account both the explicit polymer environment during the mechanophore activation process and the possibility of random chain scission to realistically model complex polymer networks, featuring longer chains, increased entanglement, and cross-linked systems. Moreover, the efficiency of the model in treating different mechanophores as well as different linkers 71 will be tested.…”

Section: Discussionmentioning

confidence: 99%

Multiscale Mechanochemical Modeling of Spiropyran–Merocyanine Isomerization in Linear PMMA Polymers

Kumar,

Demir,

Dellwisch

et al. 2023

Macromolecules

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Mechanochemical reactions in functional polymers occur when mechanical forces cause labile bonds, e.g., in mechanophores, to break. While it is known that these reactions require a critical amount of force, the structure of the polymer network strongly affects the efficiency of force transduction. Experimentally, it is challenging to track force transmission along the polymer backbone. Despite the availability of quantum mechanochemical tools, information about force transmission from the bulk to a local scale is still limited. Here, we introduce a multiscale mechanochemical model that establishes a connection between bulk deformation and mechanophore activation. This is achieved by combining the quantum mechanical (QM) constrained geometries simulate external force (COGEF) method with cost-efficient molecular mechanical (MM) simulations. Based on a new parameterization of the well-known spiropyran-to-merocyanine (SP-to-MC) isomerization under stretching forces, we simulate mechanophore activation inside a realistic poly(methyl methacrylate) (PMMA) network at different strain rates and loading modes. The results are discussed in terms of the stress–strain behavior of the system, influence of temperature, and mechanochemical activity. The developed multiscale simulation model paves the way for further investigations on more complex mechanophore-doped polymer networks subjected to external loads.

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Section: Discussionmentioning

confidence: 99%

Multiscale Mechanochemical Modeling of Spiropyran–Merocyanine Isomerization in Linear PMMA Polymers

Kumar,

Demir,

Dellwisch

et al. 2023

Macromolecules

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“…Decompression leads to the formation of the product of the rearrangement in 7 out of 10 trajectories, whereas the educt is recovered in the remaining three simulations. Our future studies will focus on the influence of environmental factors like chemical substitution 42 or the solvent in a multiscale simulation setup. We hope that our calculations spark an interest in experimental studies on the piezochemical isolation of transitory species in sigmatropic rearrangements and other chemical reactions.…”

Section: Discussionmentioning

confidence: 99%

Trapping the Transition State in a [2,3]-Sigmatropic Rearrangement by Applying Pressure

et al. 2022

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Transition states are of central importance in chemistry. While they are, by definition, transient species, it has been shown before that it is possible to "trap" transition states by applying stretching forces. We here demonstrate that the task of transforming the transition state of a chemical reaction into a minimum on the potential energy surface can be achieved using hydrostatic pressure. We apply the computational extended hydrostatic compression force field (X-HCFF) approach to the educt of a [2,3]-sigmatropic rearrangement in both static and dynamic calculations and find that the five-membered cyclic transition state of this reaction becomes a minimum at pressures in the range between 100 and 150 GPa. Born−Oppenheimer molecular dynamics (BOMD) simulations suggest that slow decompression leads to a 70:30 mix of the product and the educt of the sigmatropic rearrangement. Our findings are discussed in terms of geometric parameters and electronic rearrangements throughout the reaction. To provide reference data for experimental investigations, we simulated the IR, Raman, and time-resolved UV/vis absorption spectra for the educt, transition state, and product. We speculate that the trapping of transition states by using pressure is generally possible if the transition state of a chemical reaction has a more condensed geometry than both the educt and the product, which paves the way for new ways of initiating chemical reactions.

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“…Various techniques have been proposed to cope with this fundamental problem such as COGEF (constrained geometries simulate external force) 13 and EFEI (external forces explicitly included) 14 methods, as will be briefly summarized in Sections 2 and 3, resulting in a fair increase in quantum mechanochemical publications, sometimes also including the visualization of the distribution of the strain energy in the molecule (JEDI, Judgment of Energy Distribution). 10,15 Studies vary from the initial investigation of the mechanical strength and bond rupture in small molecules, 13 through papers on the possibility to control the stereoselectivity of pericyclic reactions including the violation of the Woodward Hoffmann rules, [16][17][18] often in synergy with experimental studies, 17,19,20 to studies on force-induced retro-click reactions, 21 mechanically induced conductance switching, 22 activation efficiency of mechanophores, 23 mechanical activation of photo-reactivity 24,25 and anthracene (4+4) cycloadducts, 26 force-induced switching of aromaticity and homo-aromaticity, 27 flex-activated mechanophores, 28 among others.…”

Section: Introductionmentioning

confidence: 99%

Wandering through quantum-mechanochemistry: from concepts to reactivity and switches

Alonso,

Bettens,

Eeckhoudt

et al. 2024

Phys. Chem. Chem. Phys.

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The activation efficiency of mechanophores can be modulated by adjacent polymer composition

Abstract: Chemical modifications of the linking units between a mechanophore and the polymer backbone can significantly enhance or reduce the rupture force of the mechanophore.

Cited by 9 publications

References 42 publications

Multiscale Mechanochemical Modeling of Spiropyran–Merocyanine Isomerization in Linear PMMA Polymers

Multiscale Mechanochemical Modeling of Spiropyran–Merocyanine Isomerization in Linear PMMA Polymers

Trapping the Transition State in a [2,3]-Sigmatropic Rearrangement by Applying Pressure

Wandering through quantum-mechanochemistry: from concepts to reactivity and switches

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