Design and Precursor-based Solid-State Synthesis of Mixed-Linker Zr-MIL-140A

Acetic acid, an alternative green solvent, was utilized for the solvothermal synthesis of four 2D materials of composition [Zr2O2(OAc)(2)(BDC-F)], [Zr2O2(OAc)(2)(BDC-F-4)], [Zr2O2(OAc)(2) (BDC)], and [Zr2O2(OAc)(2)(NDC)] (BDC, terephthalate; BDC-F, 2-fluoroterephthalate; BDC-F-4, tetrafluoroterephthalate; NDC, 2,6-naphthalenedicarboxylate). The first three compounds were subsequently reacted with terephthalic acid in solid-state reactions to form porous MIL-140A-type metal-organic frameworks and mixed-linker derivatives ([ZrO(BDC)(1-x)(BDC-Y)(x)], x = 0-0.18, Y= F, F-4). The reaction kinetics of the formation of MIL-140A were investigated with the aid of time-resolved synchrotron and temperature-resolved in-house X-ray powder diffraction experiments. Thorough compositional analyses and solid-state NMR spectroscopic experiments were used to assess the crystallographic ordering of the different linker molecules. Additionally, acetic acid-based routes for the direct synthesis of MIL-140A-NO2 and a novel MIL-140A-(CH3)(2) derivative were discovered.