Competitive Activation Experiments Reveal Significantly Different Mechanochemical Reactivity of Furan-Maleimide and Anthracene-Maleimide Mechanophores
Abstract
During the past two decades, our understanding of mechanochemical reactivity has advanced considerably. Nevertheless, an incomplete knowledge of structure–activity relationships and the principles that govern mechanochemical transformations limits molecular design. The experimental development of mechanophores has thus benefited from simple computational tools like CoGEF, from which quantitative metrics like rupture force can be extracted to estimate reactivity. Furan–maleimide (FM) and anthracene–maleimide (AM) Diels–Alder adducts are widely studied mechanophores that undergo retro-Diels–Alder reactions upon mechanical activation in polymers. Despite possessing significantly different thermal stability, similar rupture forces predicted by CoGEF calculations suggest that these compounds exhibit similar mechanochemical reactivity. Here, we directly probe the relative mechanochemical reactivity of FM and AM adducts through competitive activation experiments. Ultrasound-induced mechanochemical activation of bis-adduct mechanophores comprising covalently tethered FM and AM subunits reveals pronounced selectivity─as high as ∼13:1─for reaction of the FM adduct compared to the AM adduct. Computational models provide insight into the greater reactivity of the FM mechanophore, indicating a more efficient mechanochemical coupling for the FM adduct compared to the AM adduct. The methodology employed here to directly interrogate the relative reactivity of two different mechanophores using a tethered bis-adduct configuration may be useful for other systems where more common sonication-based approaches are limited by poor sensitivity.
Additional Information
© 2022 The Authors. Published by American Chemical Society Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/). Financial support from Caltech is gratefully acknowledged. A.C.O was supported by a NSF Graduate Research Fellowship (DGE-1745301) and an Institute Fellowship from Caltech. We thank the Center for Catalysis and Chemical Synthesis of the Beckman Institute at Caltech for access to equipment. The authors declare no competing financial interest.Attached Files
Published - lg2c00047.pdf
Supplemental Material - lg2c00047_si_001.pdf
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Additional details
- PMCID
- PMC10103189
- Eprint ID
- 118388
- Resolver ID
- CaltechAUTHORS:20221215-431170800.8
- Caltech
- DGE-1745301
- NSF Graduate Research Fellowship
- Created
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2023-01-18Created from EPrint's datestamp field
- Updated
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2023-07-06Created from EPrint's last_modified field