Several years ago, we started to synthesize different fluorinated and perfluorinated linker ligands aiming at the synthesis and characterization of isostructural coordination polymers and MOFs with different degrees of fluorination. Thus, we should be able to compare the properties of these fluorinated MOFs with those of their non-fluorinated counterparts.

In this context, we synthesized 4-fluoro-[1,1'-biphenyl]-3,3',5,5'-tetracarboxylic acid (H₄-4-mF-BPTC) and 4,4'-difluoro-[1,1'-biphenyl]-3,3',5,5'-tetracarboxylic acid (H₄-4,4’-dF-BPTC) as novel potential linker molecules. MOFs with the MFM-300 topology were chosen as a suitable system to test the properties and thermal/chemical stabilities of the resulting compounds (See Fig. 1). Investigations on the thermal properties of isotypic MFM-300 compounds showed that with increasing degree of fluorination, a decrease in thermal stability is observed. In contrast to the lower thermal stability, the N₂ uptake increases with a higher degree of fluorination.

Main Publication:

Two New MOFs Based on Cu₂ Paddlewheel Units and Biphenyltetracarboxylate Ligands with a Different Degree of Fluorination

C. Stastny, U. Ruschewitz, Z. Anorg. Allg. Chem. 2018, 644, 1908-1914.

As a second candidate for synthesis and characterization of coordination polymers and metal-organic frameworks based on ligands with different degrees of fluorination we have choosen the well established linker molecule trimesic acid. Therefore, synthesis routes for e.g. mono-, di-, and perfluorinated trimesate ligands (BTC^3‑) were established (See Fig. 2). With this library of linker molecules we try to synthesize and characterize CPs and MOFs with alkaline, alkaline earth, transition and rare earth metal ions.

Main Publications:

Reproducible Synthesis of a Monofluorinated Trimesate: A Versatile Linking Ligand for the Construction of Lanthanide Coordination Polymers

J. Krautwurst, R. Lamann, U. Ruschewitz, Z. Anorg. Allg. Chem. 2017, 643, (17), 1397–1405.

How Does the Fluorination of the Linker Affect the Stability of Trimesate-Based Coordination Polymers and Metal–Organic Frameworks?

J. Krautwurst, D. Smets, R. Lamann, U. Ruschewitz, Inorg. Chem. 2019, 58, (13), 8622-8632.

DFG- Projekt

„MOFs (metal-organic frameworks) auf Basis fluorierter und perfluorierter aromatischer Carboxylat-Liganden: Gezielte Synthese, Strukturen und Eigenschaften“.