TY  - JOUR
A1  - Mondal, Suvendu Sekhar
A1  - Dey, Subarna
A1  - Attallah, Ahmed G.
A1  - Krause-Rehberg, Reinhard
A1  - Janiak, Christoph
A1  - Holdt, Hans-Jürgen
T1  - Insights into the pores of microwave-assisted metal-imidazolate frameworks showing enhanced gas sorption
JF  - Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry
N2  - Microwave heating (MW)-assisted synthesis has been widely applied as an alternative method for the chemical synthesis of organic and inorganic materials. In this work, we report MW-assisted synthesis of three isostructural 3D frameworks with a flexible linker arm of the chelating linker 2-substituted imidazolate- 4-amide-5-imidate, named IFP-7-MW (M = Zn, R = OMe), IFP-8-MW (M = Co; R = OMe) and IFP-10-MW (M = Co; R = OEt) (IFP = Imidazolate Framework Potsdam). These chelating ligands were generated in situ by partial hydrolysis of 2-substituted 4,5-dicyanoimidazoles under MW-and also conventional electrical heating (CE)-assisted conditions in DMF. The structure of these materials was determined by IR spectroscopy and powder X-ray diffraction (PXRD) and the identity of the materials synthesized under CE-conditions was established. Materials obtained from MW-heating show many fold enhancement of CO2 and H-2 uptake capacities, compared to the analogous CE-heating method based materials. To understand the inner pore-sizes of IFP structures and variations of gas sorptions, we performed positron annihilation lifetime spectroscopy (PALS), which shows that MW-assisted materials have smaller pore sizes than materials synthesized under CE-conditions. The "kinetically controlled" MW-synthesized material has an inherent ability to trap extra linkers, thereby reducing the pore sizes of CE-materials to ultra/micropores. These ultramicropores are responsible for high gas sorption.
Y1  - 2017
U6  - https://doi.org/10.1039/c7dt00350a
SN  - 1477-9226
SN  - 1477-9234
VL  - 46
SP  - 4824
EP  - 4833
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Mondal, Suvendu Sekhar
A1  - Hovestadt, Maximilian
A1  - Dey, Subarna
A1  - Paula, Carolin
A1  - Glomb, Sebastian
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Janiak, Christoph
A1  - Hartmann, Martin
A1  - Holdt, Hans-Jürgen
T1  - Synthesis of a partially fluorinated ZIF-8 analog for ethane/ethene separation
JF  - CrystEngComm
N2  - The separation of ethane/ethene mixtures (as well as other paraffin/olefin mixtures) is one of the most important but challenging processes in the petrochemical industry. In this work, we report the synthesis of ZIF-318, isostructural to ZIF-8 but built from the mixed linkers of 2-methylimidazole (L1) and 2-trifluoromethylimidazole (L2) (ZIF-318 = [(Zn(L1)(L2)](n)). The synthesis has been optimized to proceed without ZnO-formation. Using only the L2 linker under solvothermal conditions afforded ZnO-embedded in the H-bonded and non-porous coordination polymer ZnO@[Zn-2(L2)(2)(HCOO)(OH)](n). The slight differences in the size of the substituents (-CH3 vs. -CF3) possibly in combination with different electronic inductive effects led to small but significant changes to the pore size and properties respectively, though the effective pore opening (aperture) size of ZIF-318 remained the same in comparison with ZIF-8. ZIF-318 is chemically (boiling water, methanol, benzene, and wide pH range at room temperature for 1 day), thermally (up to 310 degrees C) stable, and more hydrophobic than ZIF-8 which is proven by contact angle measurement. ZIF-318 can be activated for N-2, CO2, CH4, H-2, ethane, ethane, propane, and propene gases sorptions. Consequently, in breakthrough experiments, the ethane/ethene mixtures can be separated.
Y1  - 2017
U6  - https://doi.org/10.1039/c7ce01438d
SN  - 1466-8033
VL  - 19
SP  - 5882
EP  - 5891
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Hovestadt, Maximilian
A1  - Bendt, Stephan
A1  - Mondal, Suvendu Sekhar
A1  - Behrens, Karsten
A1  - Reif, Florian
A1  - Dopken, Merle
A1  - Holdt, Hans-Jürgen
A1  - Keil, Frerich J.
A1  - Hartmann, Martin
T1  - Experimental and Theoretical Analysis of the Influence of Different Linker Molecules in Imidazolate Frameworks Potsdam (IFP-n) on the Separation of Olefin-Paraffin Mixtures
JF  - Langmuir
N2  - Four metal organic frameworks with similar topology but different chemical environment inside the pore structure, namely, IFP-1, IFP-3, IFP-5, and IFP-7, have been investigated with respect to the separation potential for olefin paraffin mixtures as well as the influence of the different linkers on adsorption properties using experiments and Monte Carlo simulations. All IFP structures show a higher adsorption of ethane compared to ethene with the exception of IFP-7 which shows no selectivity in breakthrough experiments. For propane/propane separation, all adsorbents show a higher adsorption for the olefin. The experimental results agree quite well with the simulated values except for the IFP-7, which is presumably due to the flexibility of the structure. Moreover, the experimental and simulated isotherms were confirmed with breakthrough experiments that render IFP-1, IFP-3, and IFP-5 as suitable for the purification of ethene from ethane.
Y1  - 2017
U6  - https://doi.org/10.1021/acs.langmuir.7b02016
SN  - 0743-7463
VL  - 33
SP  - 11170
EP  - 11179
PB  - American Chemical Society
CY  - Washington
ER  -