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Shape-memory effect enabled by ligand substitution and CO2 affinity in a flexible SIFSIX coordination network
Date
2023
Abstract
We report that linker ligand substitution involving just one atom induces a shape-memory effect in a flexible coordination network. Specifically, whereas SIFSIX-23-Cu, [Cu(SiF6)(L)2]n, (L=1,4-bis(1-imidazolyl)benzene, SiF62−=SIFSIX) has been previously reported to exhibit reversible switching between closed and open phases, the activated phase of SIFSIX-23-CuN, [Cu(SiF6)(LN)2]n (LN=2,5-bis(1-imidazolyl)pyridine), transformed to a kinetically stable porous phase with strong affinity for CO2. As-synthesized SIFSIX-23-CuN, α, transformed to less open, γ, and closed, β, phases during activation. β did not adsorb N2 (77 K), rather it reverted to α induced by CO2 at 195, 273 and 298 K. CO2 desorption resulted in α′, a shape-memory phase which subsequently exhibited type-I isotherms for N2 (77 K) and CO2 as well as strong performance for separation of CO2/N2 (15/85) at 298 K and 1 bar driven by strong binding (Qst=45–51 kJ/mol) and excellent CO2/N2 selectivity (up to 700). Interestingly, α′ reverted to β after re-solvation/desolvation. Molecular simulations and density functional theory (DFT) calculations provide insight into the properties of SIFSIX-23-CuN.
Supervisor
Description
Publisher
Wiley and Sons Ltd
Citation
Angewandte Chemie International Edition, 2023, 62, e202309985
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Gao_2023_Shape.pdf
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Funding Information
We gratefully acknowledge financial support from the National Natural Science Foundation of China (Grant No. 22201025, 22371221), start-up funding from Chengdu University of Technology (10912-KYQD2022-09754), Science Foundation Ireland (14/IA/4624) and the Irish Research Council (IRCLA/2019/167). S.J.N. and M.V. acknowledge the Irish Centre for High-End Computing (ICHEC) for providing the computational facilities and support. This work was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant to S.J.N., Agreement No. 847402 (Project ID: MF20210297). Open Access funding provided by IReL.