Refine
Has Fulltext
- no (24)
Year of publication
Document Type
- Article (24) (remove)
Language
- English (24)
Is part of the Bibliography
- yes (24)
Keywords
- Solvothermal synthesis (2)
- adsorption (2)
- ionic liquids (2)
- metal-organic frameworks (2)
- Cadmium (1)
- Cobalt (1)
- Coordination polymers (1)
- Crystal structures (1)
- Flexible linker (1)
- Gas sorption (1)
Institute
A rare example of in situ linker generation with the formation of soft porous Zn- and Co-MOFs (IFP-9 and -10, respectively) is reported. The flexible ethoxy groups of IFP-9 and -10 protrude into the 1D hexagonal channels. The gas- sorption behavior of both materials for H2, CO2 and CH4 showed wide hysteretic isotherms, typical for MOFs having a flexible substituent which can give rise to a gate effect.
A Co(II)-imidazolate-4-amide-5-imidate based MOF, IFP-5, is synthesized by using an imidazolate anion-based novel ionic liquid as a linker precursor under solvothermal conditions. IFP-5 shows significant amounts of gas (N2, CO2, CH4 and H2) uptake capacities. IFP-5 exhibits an independent high spin Co(II) centre and antiferromagnetic coupling.
In this work the adsorption of CO2 and CH4 on a series of isoreticular microporous metal-organic frameworks based on 2-substituted imidazolate-4-amide-5-imidates, IFP-1-IFP-6 (IFP Imidazolate Framework Potsdam), is studied firstly by pure gas adsorption at 273 K. All experimental isotherms can be nicely described by using the Toth isotherm model and show the preferred adsorption of CO2 over CH4. At low pressures the Toth isotherm equation exhibits a Henry region, wherefore Henry's law constants for CO2 and CH4 uptake could be determined and ideal selectivity (alpha CO2/CH4) has been calculated. Secondly, selectivities were calculated from mixture data by using nearly equimolar binary mixtures of both gases by a volumetric-chromatographic method to examine the IFPs. Results showed the reliability of the selectivity calculation. Values of (alpha CO2/CH4) around 7.5 for IFP-5 indicate that this material shows much better selectivities than IFP-1, IFP-2, IFP-3, IFP-4 and IFP-6 with slightly lower selectivity (alpha CO2/CH4) = 4-6. The preferred adsorption of CO2 over CH4 especially of IFP-5 and IFP-4 makes these materials suitable for gas separation application.
A rare example of in situ linker generation with the formation of soft porous Zn- and Co-MOFs (IFP-9 and -10, respectively) is reported. The flexible ethoxy groups of IFP-9 and -10 protrude into the 1D hexagonal channels. The gas-sorption behavior of both materials for H-2, CO2 and CH4 showed wide hysteretic isotherms, typical for MOFs having a flexible substituent which can give rise to a gate effect.
Thirty six novel ionic liquids (ILs) with 1-butyl-3-methylimidazolium and 3-methyl-1-octylimidazolium cations paired with 2-substitited 4,5-dicyanoimidazolate anions (substituent at C2=chloro, bromo, methoxy, vinyl, amino, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and phenyl) have been synthesized and characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and single-crystal X-ray crystallography. The effects of cation and anion type and structure on the thermal properties of the resulting ionic liquids, including several room temperature ionic liquids (RTILs) are examined and discussed. ILs exhibited large liquid and crystallization ranges and formed glasses on cooling with glass transition temperatures in the range of -22 to -68 degrees C. The effects of alkyl substituents of the imidazolate anion reflected the crystallization, melting points and thermal decomposition of the ILs. The Coulombic packing force, van der Waals forces and size of the anions can be considered for altering the thermal transitions. Three crystal structures of the ILs were determined and the effects of changes to the cations and anions on the packing of the structure were investigated.
In situ imidazolate-4,5-diamide-2-olate linker generation leads to the formation of a [Zn-14(L2)(12)(O)-(OH)(2)(H2O)(4)] molecular building block (MBB) with a Zn-6 octahedron inscribed in a Zn-8 cube. The MBBs connect by amide-amide hydrogen bonds to a 3D robust supramolecular network which can be activated for N-2, CO2, CH4, and H-2 gas sorption.