Quantum chemical modeling of molecules under pressure

Stauch, Tim

doi:10.1002/qua.26208

Cited by 34 publications

(29 citation statements)

References 64 publications

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“…In the future we plan to apply our methodology to a recently proposed mechanophore based on anthracene, [54] for which flex‐activation was tested but remained unsuccessful, with the aim of determining the optimal conditions (e. g. the pulling/deformation setup) for successful flex‐activation. Moreover, we plan to apply quantum mechanochemical models of pressure [55–58] to test the efficiency of flex‐activation in polymers, since experiments on flex‐activated mechanophores were performed under compression [24–26] . It will be insightful to juxtapose the influences of hydrostatic pressure and mechanical forces deforming the systems, which can be assumed to play a role in the process of flex‐activation.…”

Section: Methodsmentioning

confidence: 99%

The Mechanism of Flex‐Activation in Mechanophores Revealed By Quantum Chemistry

et al. 2020

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Flex‐activated mechanophores can be used for small‐molecule release in polymers under tension by rupture of covalent bonds that are orthogonal to the polymer main chain. Using static and dynamic quantum chemical methods, we here juxtapose three different mechanical deformation modes in flex‐activated mechanophores (end‐to‐end stretching, direct pulling of the scissile bonds, bond angle bendings) with the aim of proposing ways to optimize the efficiency of flex‐activation in experiments. It is found that end‐to‐end stretching, which is a traditional approach to activate mechanophores in polymers, does not trigger flex‐activation, whereas direct pulling of the scissile bonds or displacement of adjacent bond angles are efficient methods to achieve this goal. Based on the structural, energetic and electronic effects responsible for these observations, we propose ways of weakening the scissile bonds experimentally to increase the efficiency of flex‐activation.

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Section: Methodsmentioning

confidence: 99%

The Mechanism of Flex‐Activation in Mechanophores Revealed By Quantum Chemistry

et al. 2020

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“…In the future, we plan to apply our findings to maximize the efficiency of flex-activation of mechanophores in polymers, [31][32][33] which can be used for the release of small molecules. Moreover, it is planned to apply quantum chemical models of pressure [34] to test the role of the linkers in experiments in which mechanophore activation is achieved by compression. Finally, our future studies will focus on a more realistic modeling of the polymer environment by using a multiscale model of mechanophores embedded in a polymer matrix.…”

Section: Force [Nn] -Ch 2 -Ch 2 -Ch 3 -C=n-ch 3 -C≡c-ch 3 -Nh-co-ch 3mentioning

confidence: 99%

The Activation Efficiency of Mechanophores Can Be Modulated by Adjacent Polymer Composition

Kumar¹,

Stauch²

2020

Preprint

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<div> <div> <div> <p>The activation efficiency of mechanophores in stress-responsive polymers is generally limited by the competing process of unspecific scission in other parts of the polymer chain. Here it is shown that the linker between the mechanophore and the polymer backbone determines the force needed to activate the mechanophore. Using quantum chemical methods, it is demonstrated that the activation forces of three mechanophores (Dewar benzene, benzocyclobutene and gem-dichlorocyclopropane) can be adjusted over a range of almost 300% by modifying the chemical composition of the linker. The results are discussed in terms of changes in electron density, strain distribution and structural parameters during the rupture process. Using these findings it is straightforward to either significantly enhance or reduce the activation rate of mechanophores in stress-responsive materials, depending on the desired use case. The methodology is applied to switch a one-step “gating” of a mechanochemical transformation to a two-step process. </p> </div> </div> </div>

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“…[14][15][16] At the single-molecule level, several electronic structure methods for the simulation of molecules under pressure are available. 17 A particularly notable example is the eXtreme Pressure Polarizable Continuum Model (XP-PCM), [18][19][20] in which pressure is applied to a molecule via a surrounding medium. In XP-PCM, pressure is modeled by decreasing the size of the cavity inside which the molecule is placed and simultaneously increasing the Pauli repulsion of the surrounding medium.…”

Section: Introductionmentioning

confidence: 99%

A Mechanochemical Model for the Simulation of Molecules and Molecular Crystals Under Hydrostatic Pressure

Stauch¹

2020

Preprint

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<div> <div> <div> <p>A novel mechanochemical method for the simulation of molecules and molecular crystals under hydrostatic pressure, the eXtended Hydrostatic Compression Force Field (X-HCFF) approach, is introduced. In contrast to comparable methods, the desired pressure can be adjusted non-iteratively and molecules of general shape retain chemically reasonable geometries even at high pressures. The implementation of the X-HCFF approach is straightforward and the computational cost is practically the same as for a regular geometry optimization. Pressure can be applied by using any desired electronic structure method for which a nuclear gradient is available. The results of X-HCFF for pressure-dependent intramolecular structural changes in the investigated molecules and molecular crystals as well as a simple pressure-induced dimerization reaction are chemically intuitive and fall within the range of other established computational methods. Experimental spectroscopic data of a molecular crystal under pressure are reproduced accurately. </p> </div> </div> </div>

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Quantum chemical modeling of molecules under pressure

Cited by 34 publications

References 64 publications

The Mechanism of Flex‐Activation in Mechanophores Revealed By Quantum Chemistry

The Mechanism of Flex‐Activation in Mechanophores Revealed By Quantum Chemistry

The Activation Efficiency of Mechanophores Can Be Modulated by Adjacent Polymer Composition

A Mechanochemical Model for the Simulation of Molecules and Molecular Crystals Under Hydrostatic Pressure

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