Mechanochemical Synthesis, Characterization, and Structure Determination of New Alkaline Earth Metal-Tetrafluoroterephthalate Frameworks: Ca(pBDC-F4)•4H2O, Sr(pBDC-F4)•4H2O, and Ba(pBDC-F4)

New fluorinated alkaline earth metal-organic frameworks were successfully synthesized by milling of metal hydroxides M(OH)(2) with tetrafluoroterephthalic acid H(2)pBDC-F-4. Both calcium- and strontium-tetrafluoroterephthalates are tetrahydrated, while the barium tetrafluoroterephthalate is free of coordinating water molecules. The two isomorphic structures Ca(pBDC-F-4)center dot 4H(2)O and Sr(pBDC-F-4)center dot 4H(2)O were solved from the powder diffraction data by ab initio structure determination and subsequent Rietveld refinement. The products were thoroughly characterized by elemental analysis, thermal analysis, magic angle spinning NMR, Fourier transform infrared spectroscopy, scanning electron microscopy imaging, and Brunauer-Emmett-Teller measurements. Our findings suggest that the mechanochemical synthesis route is a promising approach for the preparation of new fluorinated alkaline earth metal-organic frameworks.