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  - Bhunia, Asamanjoy
A1  - Attallah, Ahmed G.
A1  - Matthes, Philipp R.
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Müller-Buschbaum, Klaus
A1  - Krause-Rehberg, Reinhard
A1  - Janiak, Christoph
A1  - Holdt, Hans-Jürgen
T1  - Study of the Discrepancies between Crystallographic Porosity and Guest Access into Cadmium-Imidazolate Frameworks and Tunable Luminescence Properties by Incorporation of Lanthanides
JF  - Chemistry - a European journal
N2  - An extended member of the isoreticular family of metal-imidazolate framework structures, IFP-6 (IFP=imidazolate framework Potsdam), based on cadmium metal and an in situ functionalized 2-methylimidazolate-4-amide-5-imidate linker is reported. A porous 3D framework with 1D hexagonal channels with accessible pore windows of 0.52nm has been synthesized by using an ionic liquid (IL) linker precursor. IFP-6 shows significant gas uptake capacity only for CO2 and CH4 at elevated pressure, whereas it does not adsorb N-2, H-2, and CH4 under atmospheric conditions. IFP-6 is assumed to deteriorate at the outside of the material during the activation process. This closing of the metal-organic framework (MOF) pores is proven by positron annihilation lifetime spectroscopy (PALS), which revealed inherent crystal defects. PALS results support the conservation of the inner pores of IFP-6. IFP-6 has also been successfully loaded with luminescent trivalent lanthanide ions (Ln(III)=Tb, Eu, and Sm) in a bottom-up one-pot reaction through the in situ generation of the linker ligand and in situ incorporation of photoluminescent Ln ions into the constituting network. The results of photoluminescence investigations and powder XRD provide evidence that the Ln ions are not doped as connectivity centers into the frameworks, but are instead located within the pores of the MOFs. Under UV light irradiation, Tb@IFP-6 and Eu@IFP-6 ((exc)=365nm) exhibit observable emission changes to a greenish and reddish color, respectively, as a result of strong Ln 4f emissions.
KW  - adsorption
KW  - cadmium
KW  - ionic liquids
KW  - luminescence
KW  - metal-organic frameworks
Y1  - 2016
U6  - https://doi.org/10.1002/chem.201504757
SN  - 0947-6539
SN  - 1521-3765
VL  - 22
SP  - 6905
EP  - 6913
PB  - Wiley-VCH
CY  - Weinheim
ER  -