TY - JOUR A1 - Debatin, Franziska A1 - Behrens, Karsten A1 - Weber, Jens A1 - Baburin, Igor A. A1 - Thomas, Arne A1 - Schmidt, Johannes A1 - Senkovska, Irena A1 - Kaskel, Stefan A1 - Kelling, Alexandra A1 - Hedin, Niklas A1 - Bacsik, Zoltan A1 - Leoni, Stefano A1 - Seifert, Gotthard A1 - Jäger, Christian A1 - Günter, Christina A1 - Schilde, Uwe A1 - Friedrich, Alwin A1 - Holdt, Hans-Jürgen T1 - An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate Syntheses, structures and properties JF - Chemistry - a European journal N2 - We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-14, IFP=imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R=Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.01.7 angstrom), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP-2, IFP-3 and IFP-4 are isostructural to previously reported IFP-1. The structures of IFP-2 and IFP-3 were solved by X-ray crystallographic analyses. The structure of IFP-4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP-MAS NMR spectroscopy. All IFPs showed high thermal stability (345400?degrees C); IFP-1 and IFP-4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP-14 under dry conditions and that both CO2 and H2O are physisorbed on IFP-1 under moist conditions. KW - adsorption KW - metal- organic frameworks KW - microporous materials KW - N KW - O ligands KW - zinc Y1 - 2012 U6 - https://doi.org/10.1002/chem.201200889 SN - 0947-6539 VL - 18 IS - 37 SP - 11630 EP - 11640 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Jeličić, Aleksandra A1 - Friedrich, Alwin A1 - Jeremić, Katarina A1 - Siekmeyer, Gerd A1 - Taubert, Andreas T1 - Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants N2 - One of the main issues with the use of nickel titanium alloy (NiTi) implants in cardiovascular implants (stents) is that these devices must be of very high quality in order to avoid subsequent operations due to failing stents. For small stents with diameters below ca. 2 mm, however, stent characterization is not straightforward. One of the main problems is that there are virtually no methods to characterize the interior of the NiTi tubes used for fabrication of these tiny stents. The current paper reports on a robust hybrid actuator for the characterization of NiTi tubes prior to stent fabrication. The method is based on a polymer/hydrogel/magnetic nanoparticle hybrid material and allows for the determination of the inner diameter at virtually all places in the raw NiTi tubes. Knowledge of the inner structure of the raw NiTi tubes is crucial to avoid regions that are not hollow or regions that are likely to fail due to defects inside the raw tube. The actuator enables close contact of a magnetic polymer film with the inner NiTi tube surface. The magnetic signal can be detected from outside and be used for a direct mapping of the tube interior. As a result, it is possible to detect critical regions prior to expensive and slow stent fabrication processes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 161 KW - NiTi KW - inner surface KW - hydrogel KW - polybutadiene KW - magnetic nanoparticles Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-48589 ER - TY - JOUR A1 - Xie, Zai-Lai A1 - Jelicic, Aleksandra A1 - Wang, Feipeng A1 - Rabu, Pierre A1 - Friedrich, Alwin A1 - Beuermann, Sabine A1 - Taubert, Andreas T1 - Transparent, flexible, and paramagnetic ionogels based on PMMA and the iron-based ionic liquid 1-butyl-3- methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4] N2 - The iron-containing ionic liquid (IL) 1-butyl-3-methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4] has been used as a building block in the synthesis of transparent, ion-conducting, and paramagnetic ionogels. UV/Vis spectroscopy shows that the coordination around the Fe(III) ion does slightly change upon incorporation of the IL into PMMA. The thermal stability of the PMMA increases significantly with IL incorporation. In particular, the onset weight loss observed at ca. 265 degrees C for pure PMMA is completely suppressed. The ionic conductivity shows a strong temperature dependence and increases with increasing IL weight fractions. The magnetic properties are similar to those reported for the pure IL and are not affected by the incorporation into the PMMA matrix. The resulting ionogel is thus an interesting prototype for soft, flexible, and transparent materials combining the mechanical properties of the matrix with the functionality of the metal-containing IL, such as magnetism. Y1 - 2010 UR - http://www.rsc.org/Publishing/Journals/jm/index.asp U6 - https://doi.org/10.1039/C0jm01733g SN - 0959-9428 ER - TY - JOUR A1 - Benassi, Rois A1 - Bregulla, Antje A1 - Friedrich, Alwin A1 - Henning, Dietrich A1 - Heydenreich, Matthias A1 - Mickler, Wulfhard A1 - Kleinpeter, Erich A1 - Kempter, Gerhard A1 - Schilde, Uwe A1 - Taddei, F. T1 - NMR spectroscopic and theoretical structural study of 5-exo-methylene-substituted hydantoins Y1 - 1998 ER - TY - JOUR A1 - Koetz, Joachim A1 - Jagielski, Nicole A1 - Kosmella, Sabine A1 - Friedrich, Alwin A1 - Kleinpeter, Erich T1 - CdS nanocubes formed in phosphatidylcholin-based template phases N2 - The paper is focused on the characterization and use of phosphatidylcholine (PC)-based inverse microemulsions as a template phase for the CdS nanoparticle formation. The optically clear, isotropic phase in the oil corner was identified as a "classicalö water-in-oil microemulsion by means of NMR-diffusion measurements. Because of the very small dimensions of the water droplets, the isotropic phase shows a Newtonian-like flow behavior, and adequate amounts of bulk water cannot be detected by DSC. It is demonstrated that this w/o microemulsion can be used successfully as a nanoreactor for the formation of CdS nanoparticles with diameters of 4-5 nm. During the following process of solvent evaporation the individual small CdS nanoparticles aggregate to significant larger cubic nanoparticles, with an edge length of 2-40 nm, arranged in well-defined mosaic-like superstructures. In presence of SDS the nanocubes were stable up to 800 °C. It has to be stated here that polyelectrolytes prevent the formation of such well-ordered superstructures. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/09277757 U6 - https://doi.org/10.1016/j.colsurfa.2006.01.013 SN - 0927-7757 VL - 288 SP - 43 EP - 1-3 ER -