Vanadium Analogues of Nonfunctionalized and Amino-Functionalized MOFs with MIL-101 Topology – Synthesis, Characterization, and Gas Sorption Properties



Syntheses, characterization, and gas sorption properties of two new vanadium-based metal–organic frameworks [V3OCl(DMF)2(BDC)3]·3.1DMF·10H2O·0.1BDC (V–MIL-101 or 1) and [V3OCl(DMF)2(BDC–NH2)3]·2.8DMF·H2O·0.1BDC–NH2 (V–MIL-101–NH2 or 2) (DMF = N,N′-dimethylformamide; BDC = terephthalate; BDC–NH2 = 2-aminoterephthalate) having MIL-101 topology are presented. Compounds 1 and 2 were prepared under similar solvothermal conditions (150 °C, 24 h) in DMF by using VCl3 and H2BDC or H2BDC–NH2, respectively. Determination of lattice parameters from X-ray powder diffraction (XRPD) patterns of thermally activated compounds revealed their structural similarity with chromium-, iron-, and aluminum-based solids having two types of mesoporous cages and accessible metal sites. The phase purity of the compounds was ascertained by XRPD analysis, diffuse reflectance Fourier transform (DRIFT) spectroscopy, and elemental analysis. Thermogravimetric analyses (TGA) and temperature-dependent XRPD (TDXRPD) experiments indicate that the compounds are stable up to 320 and 240 °C, respectively, under an argon atmosphere. Removal of the guest DMF molecules by thermal activation enables the compounds to adsorb significant amounts of N2 (690 and 555 cm3 g–1 at p/p0 = 1 for 1 and 2, respectively) and CO2 (9.0 and 4.3 mmol g–1 at 24.5 and 22.8 bar for 1 and 2, respectively).