TY  - JOUR
A1  - Mondal, Suvendu Sekhar
A1  - Kreuzer, Alex
A1  - Behrens, Karsten
A1  - Schütz, Gisela
A1  - Holdt, Hans-Jürgen
A1  - Hirscher, Michael
T1  - Systematic experimental study on quantum sieving of hydrogen isotopes in metal-amide-imidazolate frameworks with narrow 1-D channels
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
N2  - Quantum sieving of hydrogen isotopes is experimentally studied in isostructural hexagonal metal-organic frameworks having 1-D channels, named IFP-1, -3, -4 and -7. Inside the channels, different molecules or atoms restrict the channel diameter periodically with apertures larger (4.2 angstrom for IFP-1, 3.1 angstrom for IFP-3) and smaller (2.1 angstrom for IFP-7, 1.7 angstrom for IFP-4) than the kinetic diameter of hydrogen isotopes. From a geometrical point of view, no gas should penetrate into IFP-7 and IFP-4, but due to the thermally induced flexibility, so-called gate-opening effect of the apertures, penetration becomes possible with increasing temperature. Thermal desorption spectroscopy (TDS) measurements with pure H-2 or D-2 have been applied to study isotope adsorption. Further TDS experiments after exposure to an equimolar H-2/D-2 mixture allow to determine directly the selectivity of isotope separation by quantum sieving. IFP-7 shows a very low selectivity not higher than S=2. The selectivity of the materials with the smallest pore aperture IFP-4 has a constant value of S approximate to 2 for different exposure times and pressures, which can be explained by the 1-D channel structure. Due to the relatively small cavities between the apertures of IFP-4 and IFP-7, molecules in the channels cannot pass each other, which leads to a single-file filling. Therefore, no time dependence is observed, since the quantum sieving effect occurs only at the outermost pore aperture, resulting in a low separation selectivity.
KW  - gas adsorption
KW  - hydrogen isotopes
KW  - isotope separation
KW  - metal-organic frameworks
KW  - quantum sieving
Y1  - 2019
U6  - https://doi.org/10.1002/cphc.201900183
SN  - 1439-4235
SN  - 1439-7641
VL  - 20
IS  - 10
SP  - 1311
EP  - 1315
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Alrefai, Anas
A1  - Mondal, Suvendu Sekhar
A1  - Wruck, Alexander
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Brandt, Philipp
A1  - Janiak, Christoph
A1  - Schoenfeld, Sophie
A1  - Weber, Birgit
A1  - Rybakowski, Lawrence
A1  - Herrman, Carmen
A1  - Brennenstuhl, Katlen
A1  - Eidner, Sascha
A1  - Kumke, Michael Uwe
A1  - Behrens, Karsten
A1  - Günter, Christina
A1  - Müller, Holger
A1  - Holdt, Hans-Jürgen
T1  - Hydrogen-bonded supramolecular metal-imidazolate frameworks: gas sorption, magnetic and UV/Vis spectroscopic properties
JF  - Journal of Inclusion Phenomena and Macrocyclic Chemistry
N2  - By varying reaction parameters for the syntheses of the hydrogen-bonded metal-imidazolate frameworks (HIF) HIF-1 and HIF-2 (featuring 14 Zn and 14 Co atoms, respectively) to increase their yields and crystallinity, we found that HIF-1 is generated in two different frameworks, named as HIF-1a and HIF-1b. HIF-1b is isostructural to HIF-2. We determined the gas sorption and magnetic properties of HIF-2. In comparison to HIF-1a (Brunauer-Emmett-Teller (BET) surface area of 471m(2) g(-1)), HIF-2 possesses overall very low gas sorption uptake capacities [BET(CO2) surface area=85m(2) g(-1)]. Variable temperature magnetic susceptibility measurement of HIF-2 showed antiferromagnetic exchange interactions between the cobalt(II) high-spin centres at lower temperature. Theoretical analysis by density functional theory confirmed this finding. The UV/Vis-reflection spectra of HIF-1 (mixture of HIF-1a and b), HIF-2 and HIF-3 (with 14 Cd atoms) were measured and showed a characteristic absorption band centered at 340nm, which was indicative for differences in the imidazolate framework.
KW  - Gas-sorption
KW  - Ligand design
KW  - Magnetic properties
KW  - Supramolecular chemistry
KW  - Solvothermal synthesis
Y1  - 2019
U6  - https://doi.org/10.1007/s10847-019-00926-6
SN  - 1388-3127
SN  - 1573-1111
VL  - 94
IS  - 3-4
SP  - 155
EP  - 165
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
A1  - Riemer, Janine
A1  - Müller, Holger
A1  - John, Leonard
A1  - Holdt, Hans-Jürgen
A1  - Wessig, Pablo
T1  - Na+ Selective Fluorescent Tools Based on Fluorescence Intensity Enhancements, Lifetime Changes, and on a Ratiometric Response
JF  - Chemistry - a European journal
N2  - Over the years, we developed highly selective fluorescent probes for K+ in water, which show K+-induced fluorescence intensity enhancements, lifetime changes, or a ratiometric behavior at two emission wavelengths (cf. Scheme 1, K1-K4). In this paper, we introduce selective fluorescent probes for Na+ in water, which also show Na+ induced signal changes, which are analyzed by diverse fluorescence techniques. Initially, we synthesized the fluorescent probes 2, 4, 5, 6 and 10 for a fluorescence analysis by intensity enhancements at one wavelength by varying the Na+ responsive ionophore unit and the fluorophore moiety to adjust different K-d values for an intra- or extracellular Na+ analysis. Thus, we found that 2, 4 and 5 are Na+ selective fluorescent tools, which are able to measure physiologically important Na+ levels at wavelengths higher than 500 nm. Secondly, we developed the fluorescent probes 7 and 8 to analyze precise Na+ levels by fluorescence lifetime changes. Herein, only 8 (K-d=106 mm) is a capable fluorescent tool to measure Na+ levels in blood samples by lifetime changes. Finally, the fluorescent probe 9 was designed to show a Na+ induced ratiometric fluorescence behavior at two emission wavelengths. As desired, 9 (K-d=78 mm) showed a ratiometric fluorescence response towards Na+ ions and is a suitable tool to measure physiologically relevant Na+ levels by the intensity change of two emission wavelengths at 404 nm and 492 nm.
KW  - crown compounds
KW  - fluorescence lifetime
KW  - fluorescent probes
KW  - ratiometric
KW  - sodium
Y1  - 2019
U6  - https://doi.org/10.1002/chem.201902536
SN  - 0947-6539
SN  - 1521-3765
VL  - 25
IS  - 53
SP  - 12412
EP  - 12422
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Kirste, Matthias
A1  - Brietzke, Thomas Martin
A1  - Holdt, Hans-Jürgen
A1  - Schilde, Uwe
T1  - The crystal structure of 1,12-diazaperylene, C₁₈H₁₀N₂
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - C₁₈H₁₀N₂, monoclinic, P2₁/c (no. 14), a=7.9297(9) Å,
b=11.4021(14) Å, c=13.3572(15) Å, β=105.363(8)°,
V =1164.5(2) ų, Z =4, Rgt(F)=0.0325, wRref(F²)=0.0774,
T =210(2) K.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 752 
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436501
SN  - 1866-8372
IS  - 752
ER  - 
TY  - JOUR
A1  - Kirste, Matthias
A1  - Brietzke, Thomas Martin
A1  - Holdt, Hans-Jürgen
A1  - Schilde, Uwe
T1  - The crystal structure of 1,12-diazaperylene, C₁₈H₁₀N₂
JF  - Zeitschrift für Kristallographie - New Crystal Structures
N2  - C₁₈H₁₀N₂, monoclinic, P2₁/c (no. 14), a=7.9297(9) Å,
b=11.4021(14) Å, c=13.3572(15) Å, β=105.363(8)°,
V =1164.5(2) ų, Z =4, Rgt(F)=0.0325, wRref(F²)=0.0774,
T =210(2) K.
Y1  - 2019
U6  - https://doi.org/10.1515/NCRS-2019-0385
SN  - 2196-7105
SN  - 2194-4946
VL  - 234
IS  - 6
SP  - 1255
EP  - 1257
PB  - De Gruyter
CY  - Berlin
ER  -