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Cooperative Light-Induced Breathing of Soft Porous Crystals via Azobenzene Buckling

preprint
submitted on 25.11.2020, 12:12 and posted on 26.11.2020, 05:19 by Simon Krause, Jack D. Evans, Volodymyr Bon, Stefano Crespi, Wojciech Danowski, Wesley R Browne, Sebastian Ehrling, Francesco Walenszus, Dirk Wallacher, Nico Grimm, Daniel D. Többens, Manfred S. Weiss, Stefan Kaskel, Ben L. Feringa
Although light is a prominent stimulus for smart materials, the application of photoswitches as light-responsive triggers for phase transitions of porous materials remains poorly explored. Here we incorporate an azobenzene photoswitch in the backbone of a metal-organic framework producing light-induced structural contraction of the porous network in parallel to gas adsorption. Light-stimulation enables non-invasive spatiotemporal control over the mechanical properties of the framework, which ultimately leads to pore contraction and subsequent guest release via negative gas adsorption. The complex mechanism of light-gated breathing is established by a series of in situ diffraction and spectroscopic experiments, supported by quantum mechanical and molecular dynamic simulations. Unexpectedly, this study identifies a novel light-induced deformation mechanism of constrained azobenzene photoswitches relevant to the future design of light-responsive materials.

Funding

Alexander von Humboldt Foundation

Horizon 2020 Framework Programme (Marie Skłodowska-Curie Grant No. 838280)

DFG (FOR 2433 MOF Switches, Project Nr. 279409724)

European Union’s Horizon 2020 research and innovation programme (grant agreement No. 742743)

German Federal Ministry for Education and Research (BMBF Project No 05K19OD2)

Netherlands Ministry of Education, Culture and Science (Gravitation program 024.601035)

European Research Council (ERC, advanced grant no. 694345)

History

Email Address of Submitting Author

simon.krause@rug.nl

Institution

University of Groningen

Country

Netherlands

ORCID For Submitting Author

0000-0001-9504-8514

Declaration of Conflict of Interest

no conflict of interest to declare

Version Notes

Version 1.0 - initial submission

Exports