Pore-surface engineering in metal-organic frameworks (MOFs) and metal-organic gels (MOGs) with urea-functionalized ligands for H-bond controlled gas and liquid phase separations

• Applicant: Professor Dr. Christoph Janiak
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation ; Solid State and Surface Chemistry, Material Synthesis
• Term: from 2013 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 246578769

• Final Report Year: 2017

Final Report Abstract

The designated urea-functionalized linker synthesis could be readily performed in a one-step synthesis using triphosgene. The synthesis of crystalline coordination networks with these ligands proved more difficult, due to in part low ligand solubility and probably due to ligand flexibility. Porous coordination networks or MOFs could only be obtained with a rigid urea-containing linker. Even then, the MOFs were flexible and showed dynamic porous character as evidenced by the sorption characteristics (no N2 but CO2, SO2, NH3 uptake). Crystallographic characterization of these MOFs was difficult due to small crystal size and low diffraction power because of large amounts of incorporated DMF solvent. Still, the envisioned SO2 and NH3 uptake was very high, with a new record for SO2 adsorption in a MOF. Formation of metallo-gels was observed, but more readily with related amide-functionalized ligands. Here, we have entered into a collaboration for rheology studies, which are ongoing. Due to the longer time needed for the synthesis and characterization work in WP 1 and WP 2 the planned experimental work on mixed-matrix membranes (MMMs) with the urea-functionalized materials could not be carried out as planned. The experimental MMM work was replaced by two review articles on mixed-matrix membranes, with one of them dedicated only to MOF-MMMs, the other one more general on novel porous materials as fillers for MMMs. The work is still ongoing with the rheology studies of the metallogels to be carried out and with the gas-sorption work on the urea-grafted MIL-101(Cr)- NH2.

Publications

• Enhancing Mixed-Matrix Membrane Performance with Metal-Organic Framework Additives; Cryst. Growth Des. 2017, 17 (8), 4467-4488
  J. Dechnik, C. J. Sumby, C. Janiak
  
• Metal-Organic Frameworks with Internal Urea-Functionalized Dicarboxylate Linkers for SO2 and NH3 Adsorption; ACS Appl. Mater. Interfaces 2017, 9 (42), 37419-37434 [+38-page Supporting Information]
  S. Glomb, D. Woschko, G. Makhloufi, C. Janiak
  
• Mixed-Matrix Membranes; Angew. Chem. Int. Ed. 2017, 56 (32), 9292-9310; Angew. Chem. 2017, 129 (32), 9420-9439
  J. Dechnik, J. Gascon, C. J. Doonan, C. Janiak, C. J. Sumby
  
• Urea-based flexible dicarboxylate linkers for three-dimensional metal-organic frameworks; Inorg. Chim. Acta 2017
  S. Glomb, G. Makhloufi, I. Gruber, C. Janiak