@article{25980, abstract = {{Mesoporous SBA-15 (space group p6mm), KIT-6 (Ia3d) and KIT-5 (Fm3m) silicas, exhibiting different 2-D and 3-D channel- or cage-like pore structure and pore dimensions have been used as supports for iron oxide nanoparticles. The iron modification of the silica was performed according to a frequently used impregnation technique from aqueous iron nitrate solution. The materials were characterized by nitrogen physisorption, X-ray diffraction, TEM–EDX, Moessbauer spectroscopy, and temperature-programmed reduction (TPR) and tested in the catalytic decomposition of methanol. It is established that the location and dispersion of iron oxide nanoparticles are affected by the pore topology of the support. The most homogeneously dispersed iron oxide nanoparticles are observed using silica host matrix exhibiting a 3-D channel-like structure and pore diameters about 7 nm, and the thus-obtained composites exhibit high catalytic activity and selectivity in methanol decomposition to CO and hydrogen. For all the samples, characterized with a low mesopore volume and small pore diameters/pore entrances, the formation of larger iron oxide particles, mainly located on the outer surface, is observed. Inhomogeneously dispersed iron oxide particles with a large fraction of isolated, strongly interacting with the support, iron species, and possessing low catalytic activity and usually high selectivity to methane, are found for the silicas with relatively larger pores/pore entrances.}}, author = {{Tsoncheva, Tanya and Rosenholm, Jessica and Linden, Mika and Kleitz, Freddy and Tiemann, Michael and Ivanova, Ljubomira and Dimitrov, Momtchil and Paneva, Daniela and Mitov, Ivan and Minchev, Christo}}, issn = {{1387-1811}}, journal = {{Microporous and Mesoporous Materials}}, pages = {{327--337}}, title = {{{Critical evaluation of the state of iron oxide nanoparticles on different mesoporous silicas prepared by an impregnation method}}}, doi = {{10.1016/j.micromeso.2007.10.005}}, year = {{2008}}, } @article{25979, abstract = {{Various measures to optimise the impregnation of mesoporous CMK-3 carbon and SBA-15 silica matrices with metal nitrates for the synthesis of mesoporous metal oxides by structure replication are investigated. The effect of surface modification of the matrix pores, the choice of a solvent with suitable polarity, and the concentration of the metal nitrate solution are studied in detail. The efficiency of pore loading is monitored by nitrogen physisorption measurements. The creation of polar functions at the pore surface of CMK-3 carbon is shown to increase the impregnation efficiency substantially while maximizing the pore wall polarity of SBA-15 silica by increasing the amount of free silanol groups does not have any significant impact. The choice of a less polar solvent (THF instead of water) has a positive effect on the wettability of CMK-3 carbon in the first impregnation cycle but turns out to be disadvantageous in the second cycle; a similar trend is observed for variation of the metal salt concentration.}}, author = {{Roggenbuck, Jan and Waitz, Thomas and Tiemann, Michael}}, issn = {{1387-1811}}, journal = {{Microporous and Mesoporous Materials}}, pages = {{575--582}}, title = {{{Synthesis of mesoporous metal oxides by structure replication: Strategies of impregnating porous matrices with metal salts}}}, doi = {{10.1016/j.micromeso.2007.12.018}}, year = {{2008}}, } @article{25982, abstract = {{Iron (III) containing nanoparticles with superparamagnetic behaviour are prepared via deposition on various mesoporous supports (MgO, CeO2 and SBA-15). XRD, TEM-EDX, N2 physisorption, FTIR, and Moessbauer spectroscopy are used for their characterization. The reductive properties and catalytic behaviour in methanol decomposition of the materials are also studied. Depending on the chemical nature of the support, the predominant formation of: isolated iron species, strongly interacting with the support (for SBA-15), mixture of hematite and binary MgFe2O4 nanoparticles (for MgO) or almost homogeneously dispersed hematite particles (for CeO2) are observed. The state of iron species strongly affects their catalytic properties. The favorable effect of the support mesoporosity on the catalytic activity is most pronounced for the iron modified CeO2.}}, author = {{Tsoncheva, Tanya and Roggenbuck, Jan and Tiemann, Michael and Ivanova, Lyubomira and Paneva, Daniela and Mitov, Ivan and Minchev, Christo}}, issn = {{1387-1811}}, journal = {{Microporous and Mesoporous Materials}}, pages = {{339--346}}, title = {{{Iron oxide nanoparticles supported on mesoporous MgO and CeO2: A comparative physicochemical and catalytic study}}}, doi = {{10.1016/j.micromeso.2007.06.021}}, year = {{2008}}, } @inbook{25983, abstract = {{Nanoporous semiconducting metal oxide materials (In2O3, WO3) with uniform pore systems, large specific surface areas (80 m2 g−1), and pore-wall crystallinity were prepared by structure replication, using KIT-6 silica as a template. The products show improved properties as gas sensors (for methane or butanone) as compared to non-porous samples. In addition, porous WO3 samples with comparable porosity (prepared by conventional ‘soft templating’, using pluronic P123), which are amorphous on the atomic length scale show poorer gas sensitivity, indicating that crystallinity is a crucial factor in the sensing process.}}, author = {{Waitz, Thomas and Wagner, Thorsten and Kohl, Claus-Dieter and Tiemann, Michael}}, booktitle = {{Zeolites and related materials: Trends, targets and challenges, Proceedings of the 4th International FEZA Conference}}, issn = {{0167-2991}}, title = {{{New mesoporous metal oxides as gas sensors}}}, doi = {{10.1016/s0167-2991(08)80227-3}}, year = {{2008}}, } @article{25981, abstract = {{The growth of ZnS nanoparticles during precipitation from aqueous solution is studied by in situ stopped-flow UV absorption spectroscopy at temperatures between 283 and 323 K. Particle growth is marked by substantial ripening during the first 60 ms. Kinetic data suggest that a ripening mechanism by coalescence (oriented attachment) is predominant over Ostwald ripening, although the latter seems to coexist to a significant degree at early temporal stages, predominantly at low temperatures.}}, author = {{Tiemann, Michael and Marlow, Frank and Hartikainen, Juha and Weiss, Özlem and Lindén, Mika}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, pages = {{1463--1467}}, title = {{{Ripening Effects in ZnS Nanoparticle Growth}}}, doi = {{10.1021/jp077729f}}, year = {{2008}}, } @article{25978, abstract = {{In recent years, a lot of research activity has focused on the synthesis of new ordered porous materials by utilization of porous matrices as templates. Since the matrices are themselves created by templating procedures, the entire process can be envisaged as “repeated templating”. This review describes recent conceptual developments in the field of structure replication and summarizes the large number of publications on new functional materials prepared by this method.}}, author = {{Tiemann, Michael}}, issn = {{0897-4756}}, journal = {{Chemistry of Materials}}, pages = {{961--971}}, title = {{{Repeated Templating}}}, doi = {{10.1021/cm702050s}}, year = {{2008}}, } @inbook{25984, abstract = {{Mesoporous ceria was synthesized by using both CMK-3 carbon and SBA-15 silica as structure matrices. All products exhibit uniform mesopores with diameters of 5-6 nm in a two-dimensional periodic arrangement in addition to varying amounts of interparticle porosity. The gas sensing properties (methane detection) of ordered mesoporous ceria was compared to a non-porous sample.}}, author = {{ROGGENBUCK, JAN and Tiemann, Michael}}, booktitle = {{Nanoporous Materials}}, title = {{{Mesoporous Ceria by Structure Replication from Various Porous Matrices}}}, doi = {{10.1142/9789812779168_0019}}, year = {{2008}}, } @article{38010, author = {{Navarro, Ismael and Basset, Jean-François and Hebbe, Séverine and Major, Sarah M. and Werner, Thomas and Howsham, Catherine and Bräckow, Jan and Barrett, Anthony G. M.}}, issn = {{0002-7863}}, journal = {{Journal of the American Chemical Society}}, keywords = {{Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis}}, number = {{31}}, pages = {{10293--10298}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Biomimetic Synthesis of Resorcylate Natural Products Utilizing Late Stage Aromatization: Concise Total Syntheses of the Marine Antifungal Agents 15G256ι and 15G256β}}}, doi = {{10.1021/ja803445u}}, volume = {{130}}, year = {{2008}}, } @article{58594, author = {{Ameerunisha Begum, M.S. and Seewald, Oliver and Flörke, Ulrich and Henkel, Gerald}}, issn = {{0020-1693}}, journal = {{Inorganica Chimica Acta}}, number = {{7}}, pages = {{1868--1874}}, publisher = {{Elsevier BV}}, title = {{{From the {Cu(μ2-S)N}4 butterfly architecture to the {Cu(μ3-S)N}12 double wheel}}}, doi = {{10.1016/j.ica.2007.09.047}}, volume = {{361}}, year = {{2008}}, } @inproceedings{63082, author = {{Fechner, Sabine and Sumfleth, Elke}}, booktitle = {{Concept Mapping: Connecting Educators. Proceedings of the Third International Conference on Concept Mapping, Tallinn, Estonia & Helsinki, Finland}}, editor = {{Canas, A. J. and Reiska, P. and Ahlberg, M. and Novak, J.}}, title = {{{Collaborative concept mapping in context-oriented chemistry learning}}}, year = {{2008}}, } @inproceedings{63081, author = {{Fechner, Sabine and Haugwitz, Marion and Sandmann, Angela and Sumfleth, Elke}}, booktitle = {{Proceedings of the NARST 2008 Annual Meeting, Baltimore, MD, USA}}, title = {{{Context-oriented learning and its effects on students' achievement levels in chemistry education}}}, year = {{2008}}, } @article{35353, author = {{Siebert, Hartmut and Quijada-Garrido, Isabel and Vermant, Jan and Noirez, Laurence and Burghardt, Wesley R. and Schmidt, Claudia}}, issn = {{1022-1352}}, journal = {{Macromolecular Chemistry and Physics}}, keywords = {{Materials Chemistry, Organic Chemistry, Polymers and Plastics, Physical and Theoretical Chemistry, Condensed Matter Physics}}, number = {{19–20}}, pages = {{2161--2172}}, publisher = {{Wiley}}, title = {{{Director Orientation of Nematic Side-Chain Liquid Crystalline Polymers Under Shear Flow: Comparison of a Flow-Aligning and a Non-Flow-Aligning Polysiloxane}}}, doi = {{10.1002/macp.200700248}}, volume = {{208}}, year = {{2007}}, } @article{22613, author = {{de los Arcos de Pedro, Maria Teresa and Oelhafen, Peter and Thommen, Verena and Mathys, Daniel}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, pages = {{16392--16396}}, title = {{{The Influence of Catalyst's Oxidation Degree on Carbon Nanotube Growth as a Substrate-Independent Parameter}}}, doi = {{10.1021/jp074928q}}, year = {{2007}}, } @article{22612, author = {{de los Arcos de Pedro, Maria Teresa and Oelhafen, P and Mathys, D}}, issn = {{0957-4484}}, journal = {{Nanotechnology}}, title = {{{Optical characterization of alignment and effective refractive index in carbon nanotube films}}}, doi = {{10.1088/0957-4484/18/26/265706}}, year = {{2007}}, } @article{39765, author = {{Strauß, Jochen and Hoischen, Andreas and Kitzerow, Heinz-Siegfried}}, issn = {{1542-1406}}, journal = {{Molecular Crystals and Liquid Crystals}}, keywords = {{Condensed Matter Physics, General Materials Science, General Chemistry}}, number = {{1}}, pages = {{281/[2147]--291/[2157]}}, publisher = {{Informa UK Limited}}, title = {{{An Efficient Optical Method to Detect Phase Transitions in Liquid Crystals}}}, doi = {{10.1080/15421400590955703}}, volume = {{439}}, year = {{2007}}, } @article{39782, author = {{Kitzerow, Heinz-Siegfried}}, issn = {{1058-725X}}, journal = {{Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals}}, keywords = {{Condensed Matter Physics}}, number = {{1}}, pages = {{457--472}}, publisher = {{Informa UK Limited}}, title = {{{Dual-Frequency Addressable Gratings Based on Polymer-Dispersed Liquid Crystals}}}, doi = {{10.1080/10587259808025109}}, volume = {{321}}, year = {{2007}}, } @article{39969, author = {{Kitzerow, Heinz-Siegfried and Lorenz, A. and Matthias, H.}}, issn = {{1862-6300}}, journal = {{physica status solidi (a)}}, keywords = {{Materials Chemistry, Electrical and Electronic Engineering, Surfaces, Coatings and Films, Surfaces and Interfaces, Condensed Matter Physics, Electronic, Optical and Magnetic Materials}}, number = {{11}}, pages = {{3754--3767}}, publisher = {{Wiley}}, title = {{{Tuneable photonic crystals obtained by liquid crystal infiltration}}}, doi = {{10.1002/pssa.200776404}}, volume = {{204}}, year = {{2007}}, } @article{39980, author = {{Lauhof, Marcus W. and Benning, Stephan A. and Kitzerow, Heinz-Siegfried and Vill, Volkmar and Scheliga, Felix and Thorn-Csányi, Emma}}, issn = {{0379-6779}}, journal = {{Synthetic Metals}}, keywords = {{Materials Chemistry, Metals and Alloys, Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, Electronic, Optical and Magnetic Materials}}, number = {{4-5}}, pages = {{222--227}}, publisher = {{Elsevier BV}}, title = {{{Dichroic photo- and electroluminescence of oligo p-(phenylene vinylene) derivatives}}}, doi = {{10.1016/j.synthmet.2007.01.015}}, volume = {{157}}, year = {{2007}}, } @article{39978, author = {{Matthias, Heinrich and Schweizer, Stefan L and Wehrspohn, Ralf B and Kitzerow, Heinz-Siegfried}}, issn = {{1464-4258}}, journal = {{Journal of Optics A: Pure and Applied Optics}}, keywords = {{Atomic and Molecular Physics, and Optics}}, number = {{9}}, pages = {{S389--S395}}, publisher = {{IOP Publishing}}, title = {{{Liquid crystal director fields in micropores of photonic crystals}}}, doi = {{10.1088/1464-4258/9/9/s18}}, volume = {{9}}, year = {{2007}}, } @article{39759, author = {{Kitzerow, Heinz-Siegfried and Lorenz, A. and Matthias, H.}}, issn = {{1862-6300}}, journal = {{physica status solidi (a)}}, keywords = {{Materials Chemistry, Electrical and Electronic Engineering, Surfaces, Coatings and Films, Surfaces and Interfaces, Condensed Matter Physics, Electronic, Optical and Magnetic Materials}}, number = {{11}}, pages = {{3754--3767}}, publisher = {{Wiley}}, title = {{{Tuneable photonic crystals obtained by liquid crystal infiltration}}}, doi = {{10.1002/pssa.200776404}}, volume = {{204}}, year = {{2007}}, }