@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{SchwarzeDoscheFlehretal.2010, author = {Schwarze, Thomas and Dosche, Carsten and Flehr, Roman and Klamroth, Tillmann and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Saalfrank, Peter and Cleve, Ernst and Buschmann, Hans-J{\"u}rgen and Holdt, Hans-J{\"u}rgen}, title = {Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement}, issn = {1359-7345}, year = {2010}, language = {en} } @article{SchwarzeMicklerDoscheetal.2010, author = {Schwarze, Thomas and Mickler, Wulfhard and Dosche, Carsten and Flehr, Roman and Klamroth, Tillmann and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Saalfrank, Peter and Holdt, Hans-J{\"u}rgen}, title = {Systematic investigation of photoinduced electron transfer controlled by internal charge transfer and its consequences for selective PdCl2 coordination}, issn = {0947-6539}, year = {2010}, abstract = {Fluoroionophores of fluorophore-spacer-receptor format were prepared for detection of PdCl2 by fluorescence enhancement. The fluorescent probes 1-13 consist of a fluorophore group, an alkyl spacer and a dithiomaleonitrile PdCl2 receptor. First, varying the length of the alkylene spacer (compounds 1-3) revealed a dominant through-space pathway for oxidative photoinduced electron transfer (PET) in CH2-bridged dithiomaleonitrile fluoroionophores. Second, fluorescent probes 4-9 containing two anthracene or pyrene fragments connected through CH2 bridges to the dithiomaleonitrile unit were synthesized. Modulation of the oxidation potential (EOx) through electron-withdrawing or -donating groups on the anthracene moiety regulates the thermodynamic driving force for oxidative PET (GPET) in bis(anthrylmethylthio)maleonitriles and therefore the fluorescence quantum yields (f), too. The new concept was confirmed and transferred to pyrenyl ligands, and fluorescence enhancements (FE) greater than 3.2 in the presence of PdCl2 were achieved by 7 and 8 (FE=5.4 and 5.2). Finally, for comparison, monofluorophore ligands 10-13 were synthesized.}, language = {en} } @article{SiegmannJelicic2010, author = {Siegmann, Rebekka and Jelicic, Aleksandra}, title = {Propagation and termination kinetics of PEGylated methacrylate radical polymerizations}, issn = {1022-1352}, doi = {10.1002/macp.200900527}, year = {2010}, abstract = {Propagation and chain-length averaged termination rate coefficients, k(p) and , for radical polymerizations of methacrylates carrying poly(ethylene glycol) (PEG) units are reported. kp derived from pulsed laser initiated polymerizations in bulk, in organic solvents, and in ionic liquids follows the methacrylate-type family behavior. Contrary, diffusion controlled k(t) values obtained from chemically initiated polymerizations with in-line FT- NIR monitoring of monomer conversion are strongly affected by the PEG units in the ester group. Compared to alkyl methacrylates is unexpectedly high. Moreover, of poly(ethylene glycol) ethyl ether methacrylate shows a significant reduction in k(t) already at 15\% conversion, whereas dodecyl methacrylate is constant up to at least 70\% conversion.}, language = {en} } @article{ShainyanMoskalikStarkeetal.2010, author = {Shainyan, Bagrat A. and Moskalik, Mikail Yu and Starke, Ines and Schilde, Uwe}, title = {Formation of unexpected products in the attempted aziridination of styrene with trifluoromethanesulfonyl nitrene}, issn = {0040-4020}, doi = {10.1016/j.tet.2010.08.070}, year = {2010}, abstract = {The reaction of styrene with trifluoromethanesulfonyl nitrene generated from trifluoromethanesulfonamide in the system (t-BuOCl+NaI) results in the formation of trifluoro-N-[2-phenyl-2-(trifluoromethylsulfonyl) aminoethyl]methanesulfonamide, 1-pheny1-2-iodo-ethanol, and 2,5-diphenyl-1,4-bis(trifluoromethyl sulfonyl)piperazine rather than the expected product of aziridination, 2-phenyl-1-(trifluoromethylsulfonyl) aziridine. The mechanism of the reaction is discussed.}, language = {en} } @article{SchweizerSchusterJungingeretal.2010, author = {Schweizer, S. and Schuster, T. and Junginger, Matthias and Siekmeyer, Gerd and Taubert, Andreas}, title = {Surface modification of ickel/Titanium Alloy and Titanium Surfaces via a Polyelectrolyte Multilayer/Calcium Phosphate Hybrid Coating}, issn = {1438-7492}, doi = {10.1002/mame.200900347}, year = {2010}, abstract = {The report shows that simple LbL deposition of positively charged chitosan and negatively charged heparin can be used to efficiently modify the native surface of both NiTi and Ti without any previous treatments. Moreover, mineralization of the polymer multilayers with calcium phosphate leads to surfaces with low contact angles around 70 and 20 degrees for NiTi and Ti, respectively. This suggests that a polymer multilayer/calcium phosphate hybrid coating could be useful for making NiTi or Ti implants that are at the same time antibacterial (via the chitosan), suppress blood clot formation (via the heparin), and favor fast endothelialization (via the improved surface hydrophilicity compared to the respective neat material).}, language = {en} } @article{SchwarzSieversBodenthinetal.2010, author = {Schwarz, Guntram and Sievers, Torsten K. and Bodenthin, Yves and Hasslauer, Ires and Geue, Thomas and Koetz, Joachim and Kurth, Dirk G.}, title = {The structure of metallo-supramolecular polyelectrolytes in solution and on surfaces}, issn = {0959-9428}, doi = {10.1039/B926783b}, year = {2010}, abstract = {Metal ion induced self-assembly of the rigid ligand 1,4-bis(2,2':6',2 ''-terpyridine- 4'-yl) benzene (1) with Fe(II), Co(II), Ni(II) and Zn(II) acetate in aqueous solution results in extended, rigid- rod like metallosupramolecular coordination polyelectrolytes (MEPE-1). Under the current experimental conditions the molar masses range from 1000 g mol(-1) up to 500 000 g mol(-1). The molar mass depends on concentration, stoichiometry, metal-ion and time. In addition, we present viscosity measurements, small angle neutron scattering and AFM data. We introduce a protocol to precisely control the stoichiometry during self-assembly using conductometry. The protocol can be used with different terpyridine ligands and the above-mentioned metal ions and is of paramount importance to obtain meaningful and reproducible results. As a control experiment we studied the mononuclear 4'- (phenyl)2,2':6',2 ''-terpyridine (3) complex with Ni(II) and Zn(II) and the flexible ligand 1,3- bis[4'-oxa(2,2': 6',2 ''-terpyridinyl)] propane (2) with Ni(II) acetate (Ni-MEPE-2). This ligand does not form extended macroassemblies but likely ring-like structures with 3 to 4 repeat units. Through spin- coating of Ni-MEPE-1 on a solid surface we can image the MEPEs in real space by AFM. SANS measurements of Fe-MEPE-1 verify the extended rigid-rod type structure of the MEPEs in aqueous solution.}, language = {en} } @article{SchwarzBodenthinGeueetal.2010, author = {Schwarz, Guntram and Bodenthin, Yves and Geue, Thomas and Koetz, Joachim and Kurth, Dirk G.}, title = {Structure and properties of dynamic rigid rod-like metallo-supramolecular polyelectrolytes in solution}, issn = {0024-9297}, doi = {10.1021/Ma902057f}, year = {2010}, abstract = {Metal-ion-induced self-assembly in aqueous solution of the rigid ligand 1,4-bis(2,2':6',2 ''-terpyridine-4'-yl)benzene (1) with Fe(OAc)(2) and Ni(OAc)(2) is investigated with viscosimetry, SANS, and AFM. Ligand 1 forms extended, rigid-rod like metallo-supramolecular coordination polyeectrolytes (MEPEs) with a molar mass of up to 200 000 g mol(-1) under the Current experimental conditions. The molar mass depends oil concentration, stoichiometry, and time. By spin-coating MEPEs oil a solid surface, we call image the MEPEs in real space by AFM. Both AFM and SANS confirm the extended rigid-rod-type structure of the MEPEs. As a control experiment, we also studied the flexible ligand 1,3-bis[4'-oxa(2,2':6',2 ''-terpyridinyl)]propane (2). Ligand 2 does not form extended macro-assemblies but likely ringlike structures with three 10 four repeat units. Finally, we present it protocol to control the stoichiometry during self-assembly using conductometry, which is of paramount importance to obtain meaningful and reproducible results.}, language = {en} } @article{TremblayMonturetSaalfrank2010, author = {Tremblay, Jean Christophe and Monturet, Serge and Saalfrank, Peter}, title = {Electronic damping of anharmonic adsorbate vibrations at metallic surfaces}, issn = {1098-0121}, doi = {10.1103/Physrevb.81.125408}, year = {2010}, abstract = {The nonadiabatic coupling of an adsorbate close to a metallic surface leads to electronic damping of adsorbate vibrations and line broadening in vibrational spectroscopy. Here, a perturbative treatment of the electronic contribution to the lifetime broadening serves as a building block for a new approach, in which anharmonic vibrational transition rates are calculated from a position-dependent coupling function. Different models for the coupling function will be tested, all related to embedding theory. The first two are models based on a scattering approach with (i) a jellium-type and (ii) a density functional theory based embedding density, respectively. In a third variant a further refined model is used for the embedding density, and a semiempirical approach is taken in which a scaling factor is chosen to match harmonic, single-site, first-principles transition rates, obtained from periodic density functional theory. For the example of hydrogen atoms on (adsorption) and below (subsurface absorption) a Pd(111) surface, lifetimes of and transition rates between vibrational levels are computed. The transition rates emerging from different models serve as input for the selective subsurface adsorption of hydrogen in palladium starting from an adsorption site, by using sequences of infrared laser pulses in a laser distillation scheme.}, language = {en} } @article{XieJelicicWangetal.2010, author = {Xie, Zai-Lai and Jelicic, Aleksandra and Wang, Feipeng and Rabu, Pierre and Friedrich, Alwin and Beuermann, Sabine and Taubert, Andreas}, title = {Transparent, flexible, and paramagnetic ionogels based on PMMA and the iron-based ionic liquid 1-butyl-3- methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4]}, issn = {0959-9428}, doi = {10.1039/C0jm01733g}, year = {2010}, abstract = {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.}, language = {en} } @article{SchwarzeDoscheFlehretal.2010, author = {Schwarze, Thomas and Dosche, Carsten and Flehr, Roman and Klamroth, Tillmann and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Saalfrank, Peter and Cleve, Ernst and Buschmann, Hans-J{\"u}rgen and Holdt, Hans-J{\"u}rgen}, title = {Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement}, issn = {1359-7345}, doi = {10.1039/B919973j}, year = {2010}, abstract = {The [6.6](9,10)anthracenophane 1 (Scheme 1) is a selective fluoroionophore for the detection of PdCl2 with a large fluorescence enhancement factor (I/I-0 > 250).}, language = {en} }