ABSTRACT
A 44.610.8 topology hybrid ultramicroporous material (HUM), {[Cu1.5F(SiF6)(L)2.5]·G}n, (L = 4,4'-bisimidazolylbiphenyl, G = guest molecules), 1, formed by cross-linking interpenetrated 3D four-connected CdSO4-type nets with hexafluorosilicate anions is synthesized and evaluated in the context of gas sorption and separation herein. 1 is the first HUM functionalized with two different types of fluorinated sites (SiF6 2- and F- anions) lining along the pore surface. The optimal pore size (≈5 Å) combining mixed and high-density electronegative fluorinated sites enable 1 to preferentially adsorb C2H2 over CO2 and C2H4 by hydrogen bonding interactions with a high C2H2 isosteric heat of adsorption (Qst) of ≈42.3 kJ mol-1 at zero loading. The pronounced discriminatory sorption behaviors lead to excellent separation performance for C2H2/CO2 and C2H2/C2H4 that surpasses many well-known sorbents. Dynamic breakthrough experiments are conducted to confirm the practical separation capability of 1, which reveal an impressive separation factor of 6.1 for equimolar C2H2/CO2 mixture. Furthermore, molecular simulation and density functional theory (DFT) calculations validate the strong binding of C2H2 stems from the chelating fix of C2H2 between SiF6 2- anion and coordinated F- anion.
ABSTRACT
Two novel cluster-organic frameworks based on the 12-nuclearity manganese-cluster secondary building unit (SBU), [MnIII4MnII8(L)4(Ac)8(MeO)2(µ5-O)2(H2O)4](Ac)2·16H2O (1) and [MnIII4MnII8(L)4(Ac)8(MeO)2(µ5-O)2(H2O)4](Ac)2·12H2O (2), where Ac = CH3COO- and MeO = CH3O, have been constructed from solvothermal reactions of the 3-nuclearity manganese cluster [Mn3(µ3-O)(Ac)6(py)3](ClO4) (Mn3, where py = pyridine) with a tripodal alcohol ligand containing a 4-pyridyl group. 1 and 2 represent the first examples of metal-organic frameworks containing 12-nuclearity manganese-cluster SBUs. In addition, 1 exhibits an integration of the porosity and magnetic properties from both the framework and cluster in a porous material.
