New Group 13 MIL-53 Derivates based on 2,5-Thiophenedicarboxylic Acid

A new rigid metal-organic framework (MOF) with MIL-53 topology built of 2,5-thiophenedicarboxylate (TDC) and Al, Ga or In is reported. Its structure contains chains of trans corner sharing MO6-octahedra, connected by the linker molecules to form microporous square shaped 1D channels. A combination of powder X-ray diffraction (PXRD), density functional theory (DFT) calculations and 1H, 13C and 27Al solid-state NMR spectroscopy (ssNMR) was used to analyse the structures in detail. The synthesis is easily scaled-up using microwave assisted solvothermal conditions. All materials possess a high thermal stability up to 420 °C in air and permanent porosity towards N2, H2, CO2, and CH4. Al-MIL-53-TDC shows a high specific surface area of as,BET = 1150 m2g-1 with a micropore volume of Vmic = 0.48 cm3g-1 as well as water uptake of 5.5 H2O molecules per sum formula (469 mg/g) with an a sigmoidal shape, advantageous for heat-transformation processes. Noteworthy, this material adsorbs 2.1 wt% H2 at -196 °C and 1 bar which surpasses other Al-MIL-53 compounds based on linear functionalized terephthalates.