Single crystalline hollow metal-organic frameworks: a metal-organic polyhedron single crystal as a sacrificial template

Single crystalline hollow metal-organic frameworks (MOFs) with cavity dimensions on the order of several micrometers and hundreds of micrometers were prepared using a metal-organic polyhedron single crystal as a sacrificial hard template. The hollow nature of the MOF crystal was confirmed by scanning electron microscopy of the crystal sliced using a focused ion beam.open2

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Department of Chemistryclos

Enhancement of selective heavy metal adsorption ability due to amino acid in MOF-808

N-Acethyl-L-cysteine (AcC)-grafted MOF-808 was prepared by exchanging formates at Zr metal centers of MOF-808 exposed in the solvent pore. Since MOF-808 has six formates per Zr6O4(OH)4 cluster, N-Acethyl-L-cysteine with thiol residue can be introduced into the pore up to six molecules by exchanging formate with N-Acethyl-L-cysteine. The amount of N-Acethyl-L-cysteine molecules was confirmed by NMR and the presence of thiol group was confirmed by FT-IR. Heavy metal adsorption process of AcC-grafted MOF-808 followed pseudo 2nd order kinetic model. AcC-grafted MOF-808 showed 95.9% removal of Cd2+ and its Kd value is 2.31??104, which is moderate compared to other porous systems. The maximum uptake of Cd2+ was 225.1 mg/g, which is the highest value among MOF???systems. In addition, AcC-grafted MOF-808 showed excellent selectivity for Cd2+ and Pb2+ over other alkali and transition metal ions

Molecular sieving effect ofnonporous 3-D MOF induced by selective removal of a ligated olvent molecule

A nonporous 3-D framework structure showing gas selectivity through sieving effect was produced from Ni2+ and trimesic acid (BTC). The nonporous 3-D framework doesn???t show any apparent porosity since the 1-D solvent channel along the a-axis is filled with a dimethyl ammonium ion as a counter cation. Among two different DMF molecules and a MeOH molecule ligated to the two metals out of three in the metal cluster in the 3-D framework, the MeOH molecule can be selectively removed from the framework by vacuum-drying the framework at 373 K while keeping the two coordinated DMF molecules intact. The selective removal of the ligated MeOH molecule leads to the generation of 1-D channel along the b-axis for selective gas sorption. The framework shows adsorption of CO2 with small kinetic diameter but does not show any adsorption of N2 and CH4 with large kinetic diameters. In addition, adsorption experiment for C2Hn (n = 2, 4, 6) gases indicates that adsorption amounts of the gases depend on the kinetic diameters of the C2Hn molecules