Dynamic building blocks such as molecular switches and motors engineered in permanently porous solids provide fascinating opportunities to modulate properties with external stimuli and achieve complex behaviors beyond those exhibited by the individual components. Highly porous, yet stable architectures, denominated porous switchable frameworks (PSFs), were engineered to sustain the effective isomerization of molecular switches in the solid state. We fabricate Porous Aromatic Frameworks (PAFs) with bistable molecular switches based on overcrowded alkene incorporated in the backbone of the materials. Dibrominated molecular photoswitches were copolymerized with porogenic building blocks, thus generating highly porous 3D frameworks which display BET surface areas as high as 3950 m2 g-1 and provide large free volumes that enable the conformational changes associated with the photoisomerization process.1 Indeed, upon U.V. light irradiation, solid-state 13C NMR spectroscopy demonstrates the quantitative isomerization of the light-responsive switches. Moreover, the local isomerization induced by light irradiation affects the overall porosity of the framework and modulates the bulk gas sorption properties. We extend our strategy engineering a hexadentate monomer containing an overcrowded alkene photoswitching core.2 Yamamoto homocoupling reaction yields swellable and hierarchical micro- and mesoporous architectures with densely integrated photoswitches, that can switch between stable and metastable state upon selective light irradiation. Upon light and chemical stimuli, the flexible framework endowed with hierarchical porosity can explore three unique and distinct porosity states that can be accessed in sequence. In-situ construction of spiropyran moieties with tailored functionality and precise responsivity produces highly porous dynamic materials which undergo reversible transformation of spiropyran to zwitterionic merocyanine by chemical and physical stimulation.3 These materials show potential for pH active control, responsive gas uptake and release, ions removal, and water harvesting. REFERENCES 1. Castiglioni, F.; Danowski, W.; Perego, J.; Leung F. K.-C.; Sozzani, P.; Bracco, S.; Wezenberg, S. J.; Comotti, A.; Feringa, B. L. “Modulation of porosity in a solid material enabled by bulk photoisomerization of an overcrowded alkene” Nat. Chem. 2020, 12, 595-602. 2. Sheng, J.; Perego, J.; Danowski, W.; Bracco, S.; Chen, S.; Zhu, X.; Bezuidenhout, C. X.; Krause, S.; Browne, W. R.; Sozzani, P.; Comotti, A.; Feringa, B. L. “Construction of a three-state responsive framework from a bistable photoswitch” Chem 2023, 9, 2701-2716. 3. Sheng, J.; Perego, J.; Bracco, S.; Czepa, W.; Danowski, W.; Krause, S.; Sozzani, P.; Ciesielski, A.; Comotti, A.; Feringa, B. L. “Construction of multi-stimuli responsive highly porous switchable frameworks by in-situ solid-state generation of spiropyran switches.” Adv. Mater. 2023, DOI: 10.1002/adma.202305783.
Perego, J., Sheng, J., Bezuidenhout, C., Bracco, S., Sozzani, P., Danowski, W., et al. (2023). ON COMMAND GAS SORPTION MODULATION AND MULTI-STIMULI RESPONSIVITY IN POROUS SWITCHABLE ARCHITECTURES. In Book of Abstracts.
ON COMMAND GAS SORPTION MODULATION AND MULTI-STIMULI RESPONSIVITY IN POROUS SWITCHABLE ARCHITECTURES
Jacopo Perego
Primo
;Charl X. Bezuidenhout;Silvia Bracco;Piero Sozzani;Angiolina Comotti
2023
Abstract
Dynamic building blocks such as molecular switches and motors engineered in permanently porous solids provide fascinating opportunities to modulate properties with external stimuli and achieve complex behaviors beyond those exhibited by the individual components. Highly porous, yet stable architectures, denominated porous switchable frameworks (PSFs), were engineered to sustain the effective isomerization of molecular switches in the solid state. We fabricate Porous Aromatic Frameworks (PAFs) with bistable molecular switches based on overcrowded alkene incorporated in the backbone of the materials. Dibrominated molecular photoswitches were copolymerized with porogenic building blocks, thus generating highly porous 3D frameworks which display BET surface areas as high as 3950 m2 g-1 and provide large free volumes that enable the conformational changes associated with the photoisomerization process.1 Indeed, upon U.V. light irradiation, solid-state 13C NMR spectroscopy demonstrates the quantitative isomerization of the light-responsive switches. Moreover, the local isomerization induced by light irradiation affects the overall porosity of the framework and modulates the bulk gas sorption properties. We extend our strategy engineering a hexadentate monomer containing an overcrowded alkene photoswitching core.2 Yamamoto homocoupling reaction yields swellable and hierarchical micro- and mesoporous architectures with densely integrated photoswitches, that can switch between stable and metastable state upon selective light irradiation. Upon light and chemical stimuli, the flexible framework endowed with hierarchical porosity can explore three unique and distinct porosity states that can be accessed in sequence. In-situ construction of spiropyran moieties with tailored functionality and precise responsivity produces highly porous dynamic materials which undergo reversible transformation of spiropyran to zwitterionic merocyanine by chemical and physical stimulation.3 These materials show potential for pH active control, responsive gas uptake and release, ions removal, and water harvesting. REFERENCES 1. Castiglioni, F.; Danowski, W.; Perego, J.; Leung F. K.-C.; Sozzani, P.; Bracco, S.; Wezenberg, S. J.; Comotti, A.; Feringa, B. L. “Modulation of porosity in a solid material enabled by bulk photoisomerization of an overcrowded alkene” Nat. Chem. 2020, 12, 595-602. 2. Sheng, J.; Perego, J.; Danowski, W.; Bracco, S.; Chen, S.; Zhu, X.; Bezuidenhout, C. X.; Krause, S.; Browne, W. R.; Sozzani, P.; Comotti, A.; Feringa, B. L. “Construction of a three-state responsive framework from a bistable photoswitch” Chem 2023, 9, 2701-2716. 3. Sheng, J.; Perego, J.; Bracco, S.; Czepa, W.; Danowski, W.; Krause, S.; Sozzani, P.; Ciesielski, A.; Comotti, A.; Feringa, B. L. “Construction of multi-stimuli responsive highly porous switchable frameworks by in-situ solid-state generation of spiropyran switches.” Adv. Mater. 2023, DOI: 10.1002/adma.202305783.
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