@article{AwadConradKochetal.2010, author = {Awad, Duha Jawad and Conrad, Franziska and Koch, Andreas and Friedrich, Alwin and Poeppl, Andreas and Strauch, Peter}, title = {2,2'-Bipyridin-1,2-dithiolat Gemischtligand-Komplexe : Systhese, Charakterisierung und EPR-Spektroskopie}, issn = {0932-0776}, year = {2010}, abstract = {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)}, language = {de} } @article{DebatinBehrensWeberetal.2012, author = {Debatin, Franziska and Behrens, Karsten and Weber, Jens and Baburin, Igor A. and Thomas, Arne and Schmidt, Johannes and Senkovska, Irena and Kaskel, Stefan and Kelling, Alexandra and Hedin, Niklas and Bacsik, Zoltan and Leoni, Stefano and Seifert, Gotthard and J{\"a}ger, Christian and G{\"u}nter, Christina and Schilde, Uwe and Friedrich, Alwin and Holdt, Hans-J{\"u}rgen}, title = {An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate Syntheses, structures and properties}, series = {Chemistry - a European journal}, volume = {18}, journal = {Chemistry - a European journal}, number = {37}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201200889}, pages = {11630 -- 11640}, year = {2012}, abstract = {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.}, language = {en} } @article{KoetzJagielskiKosmellaetal.2006, author = {Koetz, Joachim and Jagielski, Nicole and Kosmella, Sabine and Friedrich, Alwin and Kleinpeter, Erich}, title = {CdS nanocubes formed in phosphatidylcholin-based template phases}, volume = {288}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2006.01.013}, pages = {43 -- 1-3}, year = {2006}, abstract = {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 "classical{\"o} 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.}, language = {en} } @article{TaubertStangeLietal.2012, author = {Taubert, Andreas and Stange, Franziska and Li, Zhonghao and Junginger, Mathias and G{\"u}nter, Christina and Neumann, Mike and Friedrich, Alwin}, title = {CuO nanoparticles from the Strongly Hydrated Ionic Liquid Precursor (ILP) Tetrabutylammonium Hydroxide evaluation of the Ethanol Sensing Activity}, series = {ACS applied materials \& interfaces}, volume = {4}, journal = {ACS applied materials \& interfaces}, number = {2}, publisher = {American Chemical Society}, address = {Washington}, issn = {1944-8244}, doi = {10.1021/am201427q}, pages = {791 -- 795}, year = {2012}, abstract = {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.}, language = {en} } @article{DebatinThomasKellingetal.2010, author = {Debatin, Franziska and Thomas, Arne and Kelling, Alexandra and Hedin, Niklas and Bacsik, Zoltan and Senkovska, Irena and Kaskel, Stefan and Junginger, Matthias and M{\"u}ller, Holger and Schilde, Uwe and J{\"a}ger, Christian and Friedrich, Alwin and Holdt, Hans-J{\"u}rgen}, title = {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}, issn = {1433-7851}, doi = {10.1002/anie.200906188}, year = {2010}, abstract = {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.}, language = {en} } @article{UhlemannFriedrichHinscheetal.1995, author = {Uhlemann, Erhard and Friedrich, Alwin and Hinsche, Gerald and Mickler, Wulfhard and Schilde, Uwe}, title = {Komplexbildung und Metallextraktion mit heterocyclischen ß-Dicarbonylverbindungen im Vergleich : Struktur von 3-Phenyl-4-benzoyl-isoxazol-5-on}, year = {1995}, language = {de} } @article{GoebelHesemannFriedrichetal.2014, author = {Goebel, Ronald and Hesemann, Peter and Friedrich, Alwin and Rothe, Regina and Schlaad, Helmut and Taubert, Andreas}, title = {Modular thiol-ene chemistry approach towards mesoporous silica monoliths with organically modified pore walls}, series = {Chemistry - a European journal}, volume = {20}, journal = {Chemistry - a European journal}, number = {52}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201403982}, pages = {17579 -- 17589}, year = {2014}, abstract = {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.}, language = {en} } @article{BenassiBregullaFriedrichetal.1998, author = {Benassi, Rois and Bregulla, Antje and Friedrich, Alwin and Henning, Dietrich and Heydenreich, Matthias and Mickler, Wulfhard and Kleinpeter, Erich and Kempter, Gerhard and Schilde, Uwe and Taddei, F.}, title = {NMR spectroscopic and theoretical structural study of 5-exo-methylene-substituted hydantoins}, year = {1998}, language = {en} } @misc{JeličićFriedrichJeremićetal.2009, author = {Jeličić, Aleksandra and Friedrich, Alwin and Jeremić, Katarina and Siekmeyer, Gerd and Taubert, Andreas}, title = {Polymer hydrogel/polybutadiene/iron oxide nanoparticle hybrid actuators for the characterization of NiTi implants}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-48589}, year = {2009}, abstract = {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.}, language = {en} } @article{UhlemannLudwigHefeleetal.1995, author = {Uhlemann, Erhard and Ludwig, Eberhard and Hefele, Heike and Friedrich, Alwin and Kallies, Bernd and Schilde, Uwe and Hahn, Ekkehardt}, title = {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)}, year = {1995}, language = {de} }