Flexible metal-organic frameworks (MOFs) show the structural transition phenomena, gate opening and breathing, upon the input of external stimuli. These phenomena have significant implications in their adsorptive applications. In this work, we demonstrate the direct capture of these gate-opening and breathing phenomena, triggered by CO2 molecules, in a well-designed flexible MOF composed of rotational sites and molecular gates. Combining X-ray single crystallographic data of a flexible MOF during gate opening/closing and breathing with in situ X-ray powder diffraction results uncovered the origin of this flexibility. Furthermore, computational studies revealed the specific sites required to open these gates by interaction with CO2 molecules.
Bibliographical noteFunding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation (NRF) of K o r e a (NRF - 2013K1A3A1A04076417 ; NRF -2014R1A5A1009799; NRF-2014R1A1A2058815). The SCD and in situ XRPD experiments at PLS-II BL2D-SMC beamline were supported in part by MSIP and POSTECH (2015-second- 2D-009). The computational resources come from UNISTHPC and KISTI-PLSI. J.H.L. acknowledges the Global Ph.D. Fellowship (NRF-2013H1A2A1033501).
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