Enhancing the Water Stability of Al-MIL-101-NH2 via Postsynthetic Modification

Title data

Wittmann, Thomas ; Siegel, Renée ; Reimer, Nele ; Milius, Wolfgang ; Stock, Norbert ; Senker, Jürgen:
Enhancing the Water Stability of Al-MIL-101-NH2 via Postsynthetic Modification.
In: Chemistry : a European Journal. Vol. 21 (2015) Issue 1 . - pp. 314-323.
ISSN 1521-3765
DOI: https://doi.org/10.1002/chem.201404654

Official URL:

Abstract in another language

The resistance of metal-organic frameworks towards water is a very critical issue concerning their practical use. Recently, it was shown for microporous MOFs that the water stability could be increased by introducing hydrophobic pendant groups. Here, we demonstrate a remarkable stabilisation of the mesoporous MOF Al-MIL-101-NH2 by post-synthetic modification with phenyl isocyanate. In this process 86% of the amino groups were converted into phenylurea units. As a consequence, the long-term stability of AlMIL-101-URPh in liquid water could be extended beyond a week. In water saturated atmospheres Al-MIL-101-URPh decomposed at least 12-times slower than the unfunctionalised analogue. To study the underlying processes both materials were characterised by Ar, N-2 and H2O sorption measurements, powder X-ray diffraction, thermogravimetric and chemical analysis as well as solid-state NMR and IR spectroscopy. Postsynthetic modification decreased the BET equivalent surface area from 3363 to 1555 m(2)g(-1) for Al-MIL-101URPh and reduced the mean diameters of the mesopores by 0.6 nm without degrading the structure significantly and reducing thermal stability. In spite of similar water uptake capacities, the relative humidity-dependent uptake of Al-MIL101-URPh is slowed and occurs at higher relative humidity values. In combination with H-1-Al-27 D-HMQC NMR spectroscopy experiments this favours a shielding mechanism of the Al clusters by the pendant phenyl groups and rules out pore blocking.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Additional notes:	ISI:000346735000033
Keywords:	Hybrid materials; Metal-organic frameworks; Porosity; Postsynthetic modification; Water stability
Institutions of the University:	Faculties > Faculty of Biology, Chemistry and Earth Sciences Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Inorganic Chemistry III Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Inorganic Chemistry III > Chair Inorganic Chemistry III - Univ.-Prof. Dr. Jürgen Senker Faculties
Result of work at the UBT:	Yes
DDC Subjects:	500 Science 500 Science > 540 Chemistry
Date Deposited:	18 Mar 2021 08:18
Last Modified:	07 Feb 2023 10:05
URI:	https://eref.uni-bayreuth.de/id/eprint/64075