TY  - JOUR
AU  - Van de Voorde, Ben
AU  - Munn, Alexis
AU  - Guillou, Nathalie
AU  - Millange, Franck
AU  - De Vos, Dirk E.
AU  - Walton, Richard
TI  - Adsorption of N/S heterocycles in the flexible metal–organic framework MIL-53(FeIII) studied by in situ energy dispersive X-ray diffraction
JO  - Physical chemistry, chemical physics
VL  - 15
IS  - 22
SN  - 1463-9084
CY  - Cambridge
PB  - RSC Publ.
M1  - DESY-2014-02164
SP  - 8606 - 8615
PY  - 2013
N1  - © The Owner Societies
AB  - The adsorption of N/S-containing heterocyclic organic molecules in the flexible iron(III) terephthalate MIL-53, FeIII(OH)0.6F0.4(O2C–C6H4–CO2)·(H2O), from the liquid phase was studied with in situ energy dispersive X-ray diffraction (EDXRD), in order to follow the adsorption-induced expansion of the structure. For comparison with the diffraction data, liquid phase adsorption isotherms were recorded for uptake of benzothiophene, benzothiazole and indole in isopropanol and in heptane. The solvent not only influences pore opening but is also a competing guest. The in situ EDXRD experiments allow the kinetics of guest uptake and the competition with solvent to be monitored directly. Indole uptake is limited; this adsorbate is barely capable of opening the closed, either hydrated or dehydrated, MIL-53(Fe) structure, or of penetrating the isopropanol-containing material in the concentration range under study. When isopropanol is used as a solvent, the guest molecules benzothiophene and benzothiazole must be present at a certain threshold concentration before substantial adsorption into the metal–organic framework takes place, eventually resulting in full opening of the structure. The fully expanded structures of benzothiophene or benzothiazole loaded MIL-53(Fe) materials have Imcm symmetry and a unit cell volume of ca. 1600 Å3, and upon uptake of the guest molecules by the closed form (unit cell volume [similar]1000 Å3) no intermediate crystalline phases are seen. Successful uptake by MIL-53(Fe) requires that the adsorbate is primarily a good hydrogen bond acceptor; additionally, based on UV-visible spectroscopy, a charge-transfer interaction between the S atoms of benzothiophene and the aromatic rings in the MOF pore wall is proposed.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000319006100017
C6  - pmid:23439974
DO  - DOI:10.1039/c3cp44349c
UR  - https://bib-pubdb1.desy.de/record/167838
ER  -