Mechanical Force Enables an Anomalous Dual Ring-Opening Reaction of Naphthodipyran
Abstract
Multimodal mechanophores that exhibit complex mechanochromic behavior beyond the typical binary response are capable of distinguishing between multiple stress states through discrete changes in color. Naphthodipyran photoswitches contain two pyran rings fused to a central naphthalene core and represent a potentially promising framework for multimodal reactivity. However, the concurrent ring opening of both pyran moieties has previously proven inaccessible via photochemical activation. Here, we demonstrate that mechanical force supplied to naphthodipyran through covalently linked polymer chains generates the elusive dual ring-opened dimerocyanine product with unique near-infrared absorption properties. Trapping with boron trifluoride renders the merocyanine dyes thermally persistent and reveals apparent sequential ring-opening behavior that departs from the reactivity of previously studied mechanophores under the high strain rates imposed by ultrasound-induced solvodynamic chain extension.
Additional Information
Financial support from Caltech and an NSF CAREER award (CHE-2145791) is gratefully acknowledged. M.E.M. was supported by an NSF Graduate Research Fellowship (DGE-1745301) and a Barbara J. Burger Fellowship. S.K.O. was supported by an Institute Fellowship from Caltech. We thank Dr. Scott Virgil for helpful discussions and the Center for Catalysis and Chemical Synthesis of the Beckman institute at Caltech for access to equipment. We thank Dr. David VanderVelde for helpful discussions and technical assistance with NMR spectroscopy and the Fu laboratory at Caltech for use of their mass spectrometer. M.J.R. is an Alfred P. Sloan Research Fellow and a Camille Dreyfus Teacher-Scholar.Additional details
- Eprint ID
- 118509
- Resolver ID
- CaltechAUTHORS:20221219-418113000.37
- Caltech
- CHE-2145791
- NSF
- DGE-1745301
- NSF Graduate Research Fellowship
- Barbara J. Burger Fellowship
- Alfred P. Sloan Foundation
- Camille and Henry Dreyfus Foundation
- Created
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2023-01-24Created from EPrint's datestamp field
- Updated
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2023-03-24Created from EPrint's last_modified field