The Mechanism of Flex‐Activation in Mechanophores Revealed By Quantum Chemistry
| Autor: | Tim Stauch, Gheorghe Adam, Lennart Jonathan Mier, Sourabh Kumar |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
02 engineering and technology 010402 general chemistry 01 natural sciences Quantum chemistry Computational Chemistry Mechanochemistry Electronic effect Physical and Theoretical Chemistry Density Functional Theory Flex-Activated Mechanophores chemistry.chemical_classification Tension (physics) Communication Polymer Quantum Chemistry 021001 nanoscience & nanotechnology Communications Atomic and Molecular Physics and Optics 0104 chemical sciences Molecular geometry chemistry Chemical physics Covalent bond Density functional theory 0210 nano-technology |
| Zdroj: | Chemphyschem |
| ISSN: | 1439-7641 1439-4235 |
| DOI: | 10.1002/cphc.202000739 |
| Popis: | 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. Different deformations: Using state‐of‐the‐art Density Functional Theory and computational strain analysis, it is shown that retro‐[4+2] cycloaddition in flex‐activated mechanophores in polymers cannot be initiated by end‐to‐end stretching of the polymer main chain. By contrast, the bending of bond angles in the polymer chain adjacent to the mechanophore is appropriate for this task, leading to the release of small molecules from mechanically deformed polymers. |
| Databáze: | OpenAIRE |
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