Chiral Lanthanum Metal-Organic Framework with Gated CO2 Sorption and Concerted Framework Flexibility
Artikel i vetenskaplig tidskrift, 2022

A metal-organic framework (MOF)CTH-17based on lanthanum-(III) and the conformationally chiral linker 1,2,3,4,5,6-hexakis(4-carboxyphenyl)-benzene, cpb6-: [La2(cpb)]middot1.5dmf was prepared by the solvothermal method indimethylformamide (dmf) and characterized by variable-temperature X-raypowder diffraction (VTPXRD), variable-temperature X-ray single-crystal diffrac-tion (SCXRD), and thermogravimetric analysis (TGA).CTH-17is a rod-MOFwith new topologyoch. It has high-temperature stability with Sohncke spacegroupsP6122/P6522 at 90 K andP622 at 300 and 500 K, all phases characterizedwith SCXRD and at 293 K also with three-dimensional (3D) electron diffraction. VTPXRD indicates a third phase appearing after620 K and stable up to 770 K. Gas sorption isotherms with N2indicate a modest surface area of 231 m2g-1forCTH-17, roughly inagreement with the crystal structure. Carbon dioxide sorption reveals a gate-opening effect ofCTH-17where the structure opens upwhen the loading of CO2reaches approximately similar to 0.45 mmol g-1or 1 molecule per unit cell. Based on the SCXRD data, this isinterpreted asflexibility based on the concerted movements of the propeller-like hexatopic cpb linkers, the movementintramolecularly transmitted by the pi-pi stacking of the cpb linkers and helped by thefluidity of the LaO6coordination sphere. Thiswas corroborated by density functional theory (DFT) calculations yielding the chiral phase (P622) as the energy minimum and acompletely racemic phase (P6/mmm), with symmetric cpb linkers representing a saddle point in a racemization process


Francoise Mystere Amombo Noa

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Erik Svensson Grape

Stockholms universitet

Michelle Ahlen

Uppsala universitet

William Reinholdsson

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Christian R. Gob

Rigaku Europe SE

Francois-Xavier Coudert

Université de recherche Paris Sciences et Lettres

Ocean Cheung

Uppsala universitet

A. Ken Inge

Stockholms universitet

Lars Öhrström

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 144 19 8725-8733

Metallorganiska ramverksföreningar: syntes, topologi, katalys och magnetism

Vetenskapsrådet (VR) (2017-04725), 2018-01-01 -- 2021-12-31.


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