TY - JOUR A1 - Friedrich, Alwin A1 - Grunewald, Karsten A1 - Klinnert, Silke A1 - Bechmann, Wolfgang T1 - Thermogravimetric and differential thermal analytical investigations on sewage farm soil Y1 - 1996 ER - TY - JOUR A1 - Friedrich, Alwin A1 - Hefele, Heike A1 - Mickler, Wulfhard A1 - Mönner, Anke A1 - Uhlemann, Erhard A1 - Scholz, F. T1 - Voltammetric and potentiometric studies on the stability of vanadium(IV) complexes : a comparision of sulution phase voltammetry with the voltammetry of the microcrystalline solid compounds Y1 - 1998 ER - TY - JOUR A1 - Uhlemann, Erhard A1 - Friedrich, Alwin A1 - Hinsche, Gerald A1 - Mickler, Wulfhard A1 - Schilde, Uwe T1 - Komplexbildung und Metallextraktion mit heterocyclischen ß-Dicarbonylverbindungen im Vergleich : Struktur von 3-Phenyl-4-benzoyl-isoxazol-5-on Y1 - 1995 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 - Uhlemann, Erhard A1 - Ludwig, Eberhard A1 - Hefele, Heike A1 - Friedrich, Alwin A1 - Kallies, Bernd A1 - Schilde, Uwe A1 - Hahn, Ekkehardt T1 - Reaktionen und thermisches Verhalten oxofreier Vanadium(IV)-Komplexe. Kristallstrukturen von Methoxo- oxo[thenoyltrifluoraceton-salicylhydrazo-nato(2-)]vanadium(V) und Methoxo-oxo[benzoylaceton-salicylhydra-zonato(2- )]vanadium(V) Y1 - 1995 ER - TY - JOUR A1 - Awad, Duha Jawad A1 - Conrad, Franziska A1 - Koch, Andreas A1 - Friedrich, Alwin A1 - Poeppl, Andreas A1 - Strauch, Peter T1 - 2,2'-Bipyridin-1,2-dithiolat Gemischtligand-Komplexe : Systhese, Charakterisierung und EPR-Spektroskopie N2 - A series of new 2 2'-bipyridine/1 2-dithiolate transition metal complexes has been synthesised and characterised As 1,2-dithiolate ligands 1,2 dithiooxalate (dto) and 1 2-dithiosquarate (dtsq) were used It follows from the IR spectra that the multidentate dithiolate ligands coordinate exclusively via their sulfur atoms forming an MN2S2 coordination sphere The central metal ions (M) are Cu2+ Ni2+ Pd2+ Pt2+, and Zn2+ The complex [Cu-II(bpy)(dto)] could be studied by EPR spectroscopy and was measured as powder diamagnetically diluted in the isostructural [Ni-II(bpy)(dto)] host structure The spin density contribution calculated from the experimental parameters is compared with the electronic situation in the frontier orbitals namely in the semi occupied SOMO of the copper complex derived from quantum chemical calculations on different levels (EHT and DFT) Y1 - 2010 UR - http://www.znaturforsch.com/b.htm SN - 0932-0776 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 - TY - JOUR A1 - Debatin, Franziska A1 - Thomas, Arne A1 - Kelling, Alexandra A1 - Hedin, Niklas A1 - Bacsik, Zoltan A1 - Senkovska, Irena A1 - Kaskel, Stefan A1 - Junginger, Matthias A1 - Müller, Holger A1 - Schilde, Uwe A1 - Jäger, Christian A1 - Friedrich, Alwin A1 - Holdt, Hans-Jürgen T1 - In situ synthesis of an imidazolate-4-amide-5-imidate ligand and formation of a microporous zinc-organic framework with H2-and CO2-storage ability N2 - Narrow channels with polar walls are the structural and functional features responsible for the high capacity of a zinc-organic framework based on an imidazolate-amide-imidate ligand for the uptake of H2 and CO2 (see structure: orange Zn, blue N, red O, dark gray C, light gray H). The rigid and stable chelating ligand was synthesized in situ by partial hydrolysis of a dicyanoimidazole compound. Y1 - 2010 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/26737/ U6 - https://doi.org/10.1002/anie.200906188 SN - 1433-7851 ER - TY - JOUR A1 - Taubert, Andreas A1 - Stange, Franziska A1 - Li, Zhonghao A1 - Junginger, Mathias A1 - Günter, Christina A1 - Neumann, Mike A1 - Friedrich, Alwin T1 - CuO nanoparticles from the Strongly Hydrated Ionic Liquid Precursor (ILP) Tetrabutylammonium Hydroxide evaluation of the Ethanol Sensing Activity JF - ACS applied materials & interfaces N2 - The sensing potential of CuO nanoparticles synthesized via. precipitation from a water/ionic liquid precursor (ILP) mixture was investigated. The particles have a moderate surface area of 66 m(2)/g after synthesis, which decreases upon thermal treatment to below 5 m(2)/g. Transmission electron microscopy confirms crystal growth upon annealing, likely due to sintering effects. The as-synthesized particles can be used for ethanol sensing. The respective sensors show fast response and recovery times of below 10 s and responses greater than 2.3 at 100 ppm of ethanol at 200 degrees C, which is higher than any CuO-based ethanol sensor described so far. KW - ionic liquids KW - ionic liquid precursors KW - tetrabutylammonium hydroxide KW - nanoparticles KW - CuO KW - gas sensing Y1 - 2012 U6 - https://doi.org/10.1021/am201427q SN - 1944-8244 VL - 4 IS - 2 SP - 791 EP - 795 PB - American Chemical Society CY - Washington ER - 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 - Shkilnyy, Andriy A1 - Gräf, Ralph A1 - Hiebl, Bernhard A1 - Neffe, Axel T. A1 - Friedrich, Alwin A1 - Hartmann, Juergen A1 - Taubert, Andreas T1 - Unprecedented, low cytotoxicity of spongelike calcium phosphate/poly(ethylene imine) hydrogel composites N2 - Covalently crosslinked PEI hydrogels are efficient templates for calcium phosphate mineralization in SBF. In contrast to the PEI hydrogels, non-crosslinked PEI does not lead to calcium phosphate nucleation and growth in SBF. The precipitate is a mixture of brushite and hydroxyapatite. The PEI/calcium phosphate composite material exhibits a sponge like morphology and a chemical composition that is interesting for implants. Cytotoxicity tests using Dictyostelium discoideum amoebae show that both the non-mineralized and mineralized hydrogels have a very low cytotoxicity. This suggests that next generation PEI hydrogels, where also the degradation products are non-toxic, could be interesting for biomedical applications. Y1 - 2009 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/77002860 U6 - https://doi.org/10.1002/mabi.200800266 SN - 1616-5187 ER - TY - JOUR A1 - Goebel, Ronald A1 - Hesemann, Peter A1 - Weber, Jens A1 - Moeller, Eléonore A1 - Friedrich, Alwin A1 - Beuermann, Sabine A1 - Taubert, Andreas T1 - Surprisingly high, bulk liquid-like mobility of silica-confined ionic liquids N2 - Mesoporous silica monoliths were prepared by the sol - gel technique and. lled with 1-ethyl-3-methyl imidazolium [Emim]-X (X = dicyanamide [N(CN)(2)], ethyl sulfate [EtSO4], thiocyanate [SCN], and triflate [TfO]) ionic liquids (ILs) using a methanol-IL exchange technique. The structure and behavior of the ILs inside the silica monoliths were studied using X-ray scattering, nitrogen sorption, IR spectroscopy, solid-state NMR, and thermal analysis. DSC finds shifts in both the glass transition temperature and melting points (where applicable) of the ILs. Glass transition and melting occur well below room temperature. There is thus no conflict with the NMR and IR data, which show that the ILs are as mobile at room temperature as the bulk (not confined) ILs. The very narrow line widths of the NMR spectra suggest that the ILs in our materials have the highest mobility reported for confined ILs so far. As a result, our data suggest that it is possible to generate IL/silica hybrid materials (ionogels) with bulk-like properties of the IL. This could be interesting for applications in, e.g., the solar cell or membrane fields. Y1 - 2009 UR - http://xlink.rsc.org/jumptojournal.cfm?journal_code=CP U6 - https://doi.org/10.1039/B821833a SN - 1463-9076 ER - TY - JOUR A1 - Goebel, Ronald A1 - Hesemann, Peter A1 - Friedrich, Alwin A1 - Rothe, Regina A1 - Schlaad, Helmut A1 - Taubert, Andreas T1 - Modular thiol-ene chemistry approach towards mesoporous silica monoliths with organically modified pore walls JF - Chemistry - a European journal N2 - The surface modification of mesoporous silica monoliths through thiol-ene chemistry is reported. First, mesoporous silica monoliths with vinyl, allyl, and thiol groups were synthesized through a sol-gel hydrolysis-poly-condensation reaction from tetramethyl orthosilicate (TMOS) and vinyltriethoxysilane, allyltriethoxysilane, and (3-mercaptopropyl) trimethoxysilane, respectively. By variation of the molar ratio of the comonomers TMOS and functional silane, mesoporous silica objects containing different amounts of vinyl, allyl, and thiol groups were obtained. These intermediates can subsequently be derivatized through radical photoaddition reactions either with a thiol or an olefin, depending on the initial pore wall functionality, to yield silica monoliths with different pore-wall chemistries. Nitrogen sorption, small-angle X-ray scattering, solid-state NMR spectroscopy, elemental analysis, thermogravimetric analysis, and redox titration demonstrate that the synthetic pathway influences the morphology and pore characteristics of the resulting monoliths and also plays a significant role in the efficiency of functionalization. Moreover, the different reactivity of the vinyl and allyl groups on the pore wall affects the addition reaction, and hence, the degree of the pore-wall functionalization. This report demonstrates that thiol-ene photoaddition reactions are a versatile platform for the generation of a large variety of organically modified silica monoliths with different pore surfaces. KW - mesoporous materials KW - photochemistry KW - sol-gel processes KW - surface chemistry Y1 - 2014 U6 - https://doi.org/10.1002/chem.201403982 SN - 0947-6539 SN - 1521-3765 VL - 20 IS - 52 SP - 17579 EP - 17589 PB - Wiley-VCH CY - Weinheim 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 -