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Smets, Daniel and Ruschewitz, Uwe ORCID: 0000-0002-6511-6894 (2020). How Does the Fluorination of the Linker Affect the Structural Chemistry of Trimesate-Based Metal-Organic Frameworks (MOFs)? Z. Anorg. Allg. Chem., 646 (14). S. 1157 - 1168. WEINHEIM: WILEY-V C H VERLAG GMBH. ISSN 1521-3749

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Abstract

FMOFs, i.e. metal-organic frameworks with linkers with fluoro substituents, were supposed to show enhanced thermal and chemical stability as well as high gas affinity and hydrophobicity. However, at least for aromatic carboxylate ligands it was shown in a subsequent work that fluoro substituents weaken the C(phenyl)-COO- bond and thus facilitate decarboxylation leading to a decreased chemical and thermal stability. Nonetheless, it was concluded that linker fluorination leads to a rich structural chemistry, as the torsion angle between the phenyl ring and the carboxylate group is significantly increased in these compounds. Here, we present the very first examples of four MOFs all based on Sr2+ cations and trimesate-based linkers with three different degrees of fluorination as well as the known non-fluorinated counterpart: [Sr(HL)(H2O)]center dot n H2O [1: L = mF-BTC3-, n = 0.5, P1, Z = 2; 2: L = dF-BTC3-, n = 0.5, C2/c, Z = 8; 3: L = pF-BTC3-, n = 1.5, C2/c, Z = 8; 4: L = BTC3-, n = 0.5, P1, Z = 2; BTC3- equivalent to 1,3,5-benzenetricarboxylate (trimesate); mF-BTC3- equivalent to monofluorinated trimesate, dF-BTC3- equivalent to difluorinated trimesate, pF-BTC3- equivalent to per-(tri-)fluorinated trimesate]. Whereas 1 and known 4 are found to crystallize in isotypic structures and 2 in a very similar structural arrangement [all CN(Sr2+) = 9], 3 with the highest degree of fluorination exhibits a completely different crystal structure [CN(Sr2+) = 8], which is already obvious from the different composition. It is shown that the torsion angles between the phenyl ring and the carboxylate groups play an important structure-directing role. DSC/TGA investigations confirm that with increasing fluorination the thermal stability is decreased. However, the release temperature of water, i.e. the affinity to water, increases with the number of fluoro substituents.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Smets, Daniel UNSPECIFIED UNSPECIFIED UNSPECIFIED Ruschewitz, Uwe UNSPECIFIED orcid.org/0000-0002-6511-6894 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-334385
DOI:	10.1002/zaac.202000137
Journal or Publication Title:	Z. Anorg. Allg. Chem.
Volume:	646
Number:	14
Page Range:	S. 1157 - 1168
Date:	2020
Publisher:	WILEY-V C H VERLAG GMBH
Place of Publication:	WEINHEIM
ISSN:	1521-3749
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HYDROTHERMAL SYNTHESIS; COORDINATION POLYMERS Multiple languages Chemistry, Inorganic & Nuclear Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/33438