Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-45673 Zeitschriftenartikel Akhmetova, Irina; Schuzjajew, K.; Wilke, M.; de Oliveira Guilherme Buzanich, Ana; Rademann, K.; Roth, C.; Emmerling, Franziska Synthesis, characterization and in situ monitoring of the mechanochemical reaction process of two manganese(II)-phosphonates with N-containing ligands Two divalent manganese aminophosphonates, manganese mono (nitrilotrimethylphosphonate) (MnNP3) and manganese bis N-(carboxymethyl)iminodi(methylphosphonate)) (Mn(NP2AH)2), have been prepared by mechanochemical synthesis and characterized by powder X-ray diffraction (PXRD). The structure of the novel compound Mn(NP2AH)2 was determined from PXRD data. MnNP3 as well as Mn(NP2AH)2 exhibits a chain-like structure. In both cases, the manganese atom is coordinated by six oxygen atoms in a distorted octahedron. The local coordination around Mn was further characterized by extended X-ray absorption fine structure. The synthesis process was followed in situ by synchrotron X-ray diffraction revealing a three-step reaction mechanism. The asprepared manganese(II) phosphonates were calcined on air. All samples were successfully tested for their suitability as catalyst material in the oxygen evolution reaction. Springer Science + Business Media B.V. 2018 Journal of Materials Science 53 19 13390 13399 10.1007/s10853-018-2608-6 2018-08-09 OPUS4-874 Zeitschriftenartikel Cappella, Brunero; Geuss, Markus; Sturm, Heinz; Heyde, M.; Rademann, K.; Spangenberg, T.; Niehus, H. Dynamic plowing nanolithography on polymethylmethacrylate using an atomic force microscope We present dynamic plowing nanolithography on polymethylmethacrylate films, performed with a scan-linearized atomic force microscope able to scan up to 250 μm with high resolution. Modifications of the surface are obtained by plastically indenting the film surface with a vibrating tip. By changing the oscillation amplitude of the cantilever, i.e., the indentation depth, surfaces can be either imaged or modified. A program devoted to the control of the scanning process is also presented. The software basically converts the gray scale of pixel images into voltages used to control the dither piezo driving cantilever oscillations. The advantages of our experimental setup and the dependence of lithography efficiency on scanning parameters are discussed. Some insights into the process of surface modifications are presented. Melville, NY American Institute of Physics 2001 Review of scientific instruments 72 136 141 10.1063/1.1326053 2016-02-19 OPUS4-875 Zeitschriftenartikel Sturm, Heinz; Cappella, Brunero; Heyde, M.; Ritter, C.; Rademann, K. Dislocation of antimony clusters on graphite by means of dynamic plowing nanolithography Antimony clusters of different shapes and dimensions have been obtained by evaporating antimony on graphite. The dependence of the shape and dimensions of the particles on the evaporation parameters (effective layer thickness, temperature, pressure) is discussed. A characterisation of the different structures is presented. In particular, the decoration of graphite steps is discussed. Clusters have been dislocated by means of dynamic plowing nanolithography, both in vector and in image pattern mode. The dependence of the energy needed to dislocate a cluster on its dimensions and position is discussed. Amsterdam Elsevier 2001 Surface science 476 1-2 54 62 10.1016/S0039-6028(00)01113-4 2016-02-19 OPUS4-7679 Zeitschriftenartikel Ritter, C.; Schwarz, U.D.; Stegemann, Bert; Heyde, M.; Rademann, K. Tribological properties of amorphous and crystalline antimony nanoparticles studied by SFM and TEM Bad Honnef Deutsche Physikalische Gesellschaft 2005 Verhandlungen der Deutschen Physikalischen Gesellschaft 40 02 475 476 2016-02-19 OPUS4-7680 Beitrag zu einem Tagungsband Ritter, C.; Heyde, M.; Stegemann, Bert; Rademann, K.; Schwarz, U.D. Moving adsorbed particles by scanning force microscopy: A new gateway to the study of nanoscale frictional properties Sesimbra ESF 2004 Proceedings of the 3rd ESF Nanotribology Workshop 3rd ESF Nanotribology Workshop Sesimbra, Portugal 2004-09-18 2004-09-22 34 2016-02-19 OPUS4-7691 Zeitschriftenartikel Eichelbaum, M.; Rademann, K.; Müller, Ralf; Radtke, Martin; Görner, Wolf Zur Chemie des Goldes in Silicatgläsern: Untersuchungen zum nicht-thermisch aktivierten Wachstum von Goldclustern Weinheim Wiley-VCH Gesellschaft Deutscher Chemiker 2005 Angewandte Chemie 117 48 8118 8122 10.1002/ange.200502174 2016-02-19 OPUS4-25597 Zeitschriftenartikel Klimakow, Maria; Klobes, Peter; Rademann, K.; Emmerling, Franziska Characterization of mechanochemically synthesized MOFs The compound MOF-14 (Cu3(BTB)2, BTB = 4,4',4''-benzenetribenzoate) was synthesized by ball milling and characterized by powder X-ray diffraction (XRD). The raw material was activated using an efficient single washing step to ensure a free pore access. Nitrogen adsorption measurements were carried out to determine the specific areas of the samples before and after activation. To interpret the activation process in terms of blocking effects in the micropore channels, NLDFT evaluations (Nonlocal Density Functional Theory) of the MOF-14 nitrogen isotherms were carried out. In connection with the appearance of additional hysteresis loops in the nitrogen isotherms, calculations of the mesopore size distribution were performed using the method of Barret, Joyner, and Halenda (BJH). The results are compared to those of a structurally analogue MOF, namely HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate). This comparison showed notable differences regarding the impact of the activation step on the formation of mesopores and their size distribution. Amsterdam Elsevier 2012 Microporous and mesoporous materials 154 113 118 10.1016/j.micromeso.2011.11.039 2016-02-19 OPUS4-26347 Zeitschriftenartikel Kahlau, R.; Gnutzmann, Tanja; Emmerling, Franziska; Rademann, K.; Rössler, E.A. Quinaldine: Accessing two crystalline polymorphs via the supercooled liquid Quinaldine (2-methyl quinoline) is a liquid at room temperature, which can be supercooled to reach finally the glassy state. By heating the glass above the glass transition temperature Tg = 180 K the sample performs two subsequent transitions into, likewise, dielectrically active phases. Thus, the reorientational relaxations of these phases as well as the kinetics of the phase transitions can be tracked in a highly resolved way by dielectric spectroscopy. X-ray diffraction analysis clearly shows two structurally different crystalline phases in addition to the supercooled liquid. Calorimetric measurements support the notion of first order phase transitions, occurring irreversibly in the supercooled regime, and suggest that the intermediate crystalline phase is metastable, too. Analyzing the quite distinct dielectric relaxation strengths, we discuss the possible nature of the two crystalline phases. Additionally, a very similar behavior to quinaldine is observed for 3-methyl quinoline, indicating a broad field of polymorphism among the quinoline derivatives. Melville, NY American Institute of Physics 2012 The journal of chemical physics 137 5 054505-1 - 054505-10 10.1063/1.4738583 2016-02-19 OPUS4-27539 Zeitschriftenartikel Simo, A.; Polte, Jörg; Pfänder, N.; Vainio, U.; Emmerling, Franziska; Rademann, K. Formation mechanism of silver nanoparticles stabilized in glassy matrices In any given matrix control over the final particle size distribution requires a constitutive understanding of the mechanisms and kinetics of the particle evolution. In this contribution we report on the formation mechanism of silver nanoparticles embedded in a soda-lime silicate glass matrix. For the silver ion-exchanged glass it is shown that at temperatures below 410 °C only molecular clusters (diameter <1 nm) are forming which are most likely silver dimers. These clusters grow to nanoparticles (diameter >1 nm) by annealing above this threshold temperature of 410 °C. It is evidenced that the growth and thus the final silver nanoparticle size are determined by matrix-assisted reduction mechanisms. As a consequence, particle growth proceeds after the initial formation of stable clusters by addition of silver monomers which diffuse from the glass matrix. This is in contrast to the widely accepted concept of particle growth in metal-glass systems, in which it is assumed that the nanoparticle formation is predominantly governed by Ostwald ripening processes. Washington, DC American Chemical Society 2012 Journal of the American chemical society 134 45 18824 18833 10.1021/ja309034n 2016-02-20 OPUS4-27735 Zeitschriftenartikel Gnutzmann, Tanja; Rademann, K.; Emmerling, Franziska Fast crystallization of organic glass formers An unusually fast crystallization of the organic glass former nifedipine has been observed. The crystallization process, starting from an amorphous film to crystalline material, was investigated by time resolved Raman microspectroscopy. The crystallization rates of the initially crystallizing metastable β-form are four orders of magnitude higher than those of previous studies. Cambridge Royal Society of Chemistry Chemical Society 2012 Chemical communications 48 1638 1640 10.1039/c1cc16301a 2016-02-20 OPUS4-25457 Zeitschriftenartikel Sarfraz, Adnan; Simo, A.; Fenger, R.; Christen, W.; Rademann, K.; Panne, Ulrich; Emmerling, Franziska Morphological diversity of caffeine on surfaces: needles and hexagons A systematic crystal morphology study on the pharmaceutical model compound caffeine has been conducted on different surfaces: silicon, silver, soda lime glass, and silver subsurface ion-exchanged soda-lime silicate (SIMO) glasses. The morphology of the solid caffeine deposits has been investigated using environmental scanning electron microscopy (ESEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). Needle-shaped caffeine crystals have been observed by drop-casting and also by applying the rapid expansion of supercritical solutions (RESS) technique using supercritical carbon dioxide. The aspect ratio of the crystalline needles typically vary between 10 and 100, but have been observed as large as 500. The XRD data of the RESS products indicate unambiguously the presence of the thermodynamically most stable polymorph of caffeine known as the β-form. Under defined conditions we observe a unique, surface-mediated morphology for caffeine crystals with nearly perfect hexagonal shape. The relative fraction of the hexagons was seen to strongly increase especially when SIMO glasses were used. These hexagons have a distinct upper size limit depending on the solvent and substrate being used. The size distribution analysis of the hexagons yielded an average perimeter of typically 10 µm. The mechanism of the formation process of this new hexagonal motif is explained in terms of the spinodal dewetting of the thin film of caffeine solution on the surface. Washington, DC, USA American Chemical Society American Chemical Society 2012 Crystal growth & design 12 2 583 588 10.1021/cg101358q 2016-02-19 OPUS4-26278 Zeitschriftenartikel Som, T.; Simo, A.; Fenger, R.; Troppenz, G.V.; Bansen, R.; Pfänder, N.; Emmerling, Franziska; Rappich, J.; Boeck, T.; Rademann, K. Bismuth hexagons: facile mass synthesis, stability and applications A unique direct electrodeposition technique involving very high current densities, high voltages and high electrolyte concentrations is applied for highly selective mass synthesis of stable, isolable, surfactant-free, single-crystalline Bi hexagons on a Cu wire at room temperature. A formation mechanism of the hexagons is proposed. The morphology, phase purity, and crystallinity of the material are well characterized by FESEM, AFM, TEM, SAED, EDX, XRD, and Raman spectroscopy. The thermal stability of the material under intense electron beam and intense laser light irradiation is studied. The chemical stability of elemental Bi in nitric acid shows different dissolution rates for different morphologies. This effect enables a second way for the selective fabrication of Bi hexagons. Bi hexagons can be oxidized exclusively to α-Bi2O3 hexagons. The Bi hexagons are found to be promising for thermoelectric applications. They are also catalytically active, inducing the reduction of 4-nitrophenol to 4-aminophenol. This electrodeposition methodology has also been demonstrated to be applicable for synthesis of bismuth-based bimetallic hybrid composites for advanced applications. Weinheim Wiley-VCH 2012 ChemPhysChem 13 8 2162 2169 10.1002/cphc.201101009 2016-02-19 OPUS4-7558 Beitrag zu einem Sammelband Eichelbaum, M.; Rademann, K.; Müller, Ralf; Radtke, Martin; Riesemeier, Heinrich; Görner, Wolf Vom Atom zum Nanodraht: Kontrolliertes Wachstum von Edelmetall-Nanokristalliten in Kalk-Natron-Silikatglas Offenbach Deutsche Glastechnische Gesellschaft 2005 Programm und Referate / 79. Glastechnische Tagung 3-921089-43-3 79. Glastechnische Tagung Würzburg, Deutschland 2005-05-23 2005-05-25 15 Seiten 2016-02-19 OPUS4-14186 Zeitschriftenartikel Görner, Wolf; Eichelbaum, Maik; Matschat, Ralf; Rademann, K.; Radtke, Martin; Reinholz, Uwe; Riesemeier, Heinrich Non-destructive investigation of composition, chemical properties and structure of materials by synchrotron radiation Northampton British Institute of Non-Destructive Testing 2006 Insight 48 9 540 544 2016-02-19 OPUS4-16432 Zeitschriftenartikel Eichelbaum, M.; Rademann, K.; Weigel, W.; Löchel, B.; Radtke, Martin; Müller, Ralf Gold-Ruby Glass in a New Light: On the Microstructuring of Optical Glasses with Synchrotron Radiation London World Gold Council 2007 Gold Bulletin 40 4 1 5 2016-02-19 OPUS4-17818 Zeitschriftenartikel Leiterer, Jork; Emmerling, Franziska; Panne, Ulrich; Christen, W.; Rademann, K. Tracing Coffee Tabletop Traces Crystallization processes under different conditions are of fundamental interest in chemistry, pharmacy, and medicine. Therefore, we have studied the formation of micro- and nanosized crystals using water-caffeine (1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione) solutions under ambient conditions as a relevant model system. When droplets of an aqueous caffeine solution evaporate and eventually dry on surfaces (glass, polystyrene, and polyester), stable “coffee tabletop” rings with a perimeter of typically 3 mm are formed after 20 to 50 min. Using a micro focus X-ray beam available at the BESSY µSpot-beamline, the fine structure of different caffeine needles can be distinguished. Unexpectedly, both crystal modifications (α- and β-caffeine) are present, but locally separated in these rings. Furthermore, AFM studies reveal the presence of even smaller particles on a nanometer length scale. To eliminate influences of surface irregularities from the crystallization process, acoustic levitation of liquid samples was employed. Such levitated droplets are trapped in a stable position and only surrounded by air. The solvent in an ultrasonically levitated drop evaporates completely, and the resulting crystallization of caffeine was followed in situ by synchrotron X-ray diffraction. In this case, the diffraction pattern is in accordance with pure α-caffeine and does not indicate the formation of the room temperature polymorph β-caffeine. Hence, our investigations open new vistas that may lead to a controlled formation of cocrystals and novel polymorphs of micro- and nanocrystalline materials, which are of relevance for fundamental studies as well as for pharmaceutical and medical applications. Washington, DC American Chemical Society 2008 Langmuir 24 15 7970 7978 10.1021/la800768v 2016-02-19 OPUS4-18233 Zeitschriftenartikel Eichelbaum, M.; Kneipp, Janina; Schmidt, B.E.; Panne, Ulrich; Rademann, K. SERS and Multiphoton-Induced Luminescence of Gold Micro- and Nanostructures Fabricated by NIR Femtosecond-Laser Irradiation Weinheim Wiley-VCH Verl. 2008 ChemPhysChem : a European journal of chemical physics and physical chemistry 9 15 2163 2167 10.1002/cphc.200800417 2016-02-19 OPUS4-6857 Zeitschriftenartikel Sturm, Heinz; Heyde, M.; Rademann, K. The use of a fibre-based light sensor for the calibration of Scanning Probe Microscopy piezos Berlin Wiley-VCH 1999 Physica status solidi A 173 1 225 234 2016-02-19 OPUS4-6858 Zeitschriftenartikel Heyde, M.; Sturm, Heinz; Rademann, K. New application for the calibration of scanning probe microscopy piezos Chichester Wiley 1999 Surface and interface analysis 27 5-6 291 295 2016-02-19 OPUS4-6860 Zeitschriftenartikel Sturm, Heinz; Heyde, M.; Rademann, K. Measuring SPM Piezo Displacement Responses Wappingers Falls, NY Microscopy Society of America 1999 Microscopy today 99 4 24 26 2016-02-19 OPUS4-6861 Zeitschriftenartikel Heyde, M.; Sturm, Heinz; Geuss, Markus; Ritter, C.; Rademann, K. Rastersondenmikroskopie als Werkzeug der Lithographie für Nanostrukturen Berlin Universität 1999 Humboldt-Spektrum 6 3 28 33 2016-02-19 OPUS4-20940 Zeitschriftenartikel Polte, Jörg; Erler, Robert; Thünemann, Andreas; Sokolov, S.; Ahner, T. T.; Rademann, K.; Emmerling, Franziska; Kraehnert, R. Nucleation and growth of gold nanoparticles studies via in situ small angle X-ray scattering at millisecond time resolution Gold nanoparticles (AuNP) were prepared by the homogeneous mixing of continuous flows of an aqueous tetrachloroauric acid solution and a sodium borohydride solution applying a microstructured static mixer. The online characterization and screening of this fast process (~2 s) was enabled by coupling a micromixer operating in continuous-flow mode with a conventional in-house small angle X-ray scattering (SAXS) setup. This online characterization technique enables the time-resolved investigation of the growth process of the nanoparticles from an average radius of ca. 0.8 nm to about 2 nm. To the best of our knowledge, this is the first demonstration of a continuous-flow SAXS setup for time-resolved studies of nanoparticle formation mechanisms that does not require the use of synchrotron facilities. In combination with X-ray absorption near edge structure microscopy, scanning electron microscopy, and UV-vis spectroscopy the obtained data allow the deduction of a two-step mechanism of gold nanoparticle formation. The first step is a rapid conversion of the ionic gold precursor into metallic gold nuclei, followed by particle growth via coalescence of smaller entities. Consequently it could be shown that the studied synthesis serves as a model system for growth driven only by coalescence processes. Washington, DC, USA ACS Publ. American Chemical Society 2010 ACS nano 4 2 1076 1082 10.1021/nn901499c 2016-02-19 OPUS4-26071 Zeitschriftenartikel Fenger, A.; Fertitta, E.; Kirmse, H.; Thünemann, Andreas; Rademann, K. Size dependent catalysis with CTAB-stabilized gold nanoparticles CTAB-stabilized gold nanoparticles were synthesized by applying the seeding-growth approach in order to gain information about the size dependence of the catalytic reduction of p-nitrophenol to p-aminophenol with sodium borohydride. Five different colloidal solutions of stabilized gold nanoparticles have been characterized by TEM, AFM, UV-Vis, SAXS, and DLS for their particle size distributions. Gold nanoparticles (mean sizes: 3.5, 10, 13, 28, 56 nm diameter) were tested for their catalytic efficiency. Kinetic data were acquired by UV-Vis spectroscopy at different temperatures between 25 and 45 °C. By studying the p-nitrophenol to p-aminophenol reaction kinetics we determined the nanoparticle size which is needed to gain the fastest conversion under ambient conditions in the liquid phase. Unexpectedly, CTAB-stabilized gold nanoparticles with a diameter of 13 nm are most efficient. Cambridge The Royal Soc. of Chemistry 2012 Physical chemistry, chemical physics 14 26 9343 9349 10.1039/c2cp40792b 2016-02-19 OPUS4-26427 Zeitschriftenartikel Polte, Jörg; Tuaev, X.; Wuithschick, M.; Fischer, A.; Thünemann, Andreas; Rademann, K.; Kraehnert, R.; Emmerling, Franziska Formation mechanism of colloidal silver nanoparticles: analogies and differences to the growth of gold nanoparticles The formation mechanisms of silver nanoparticles using aqueous silver perchlorate solutions as precursors and sodium borohydride as reducing agent were investigated based on time-resolved in situ experiments. This contribution addresses two important issues in colloidal science: (i) differences and analogies between growth processes of different metals such as gold and silver and (ii) the influence of a steric stabilizing agent on the growth process. The results reveal that a growth due to coalescence is a fundamental growth principle if the monomer-supplying chemical reaction is faster than the actual particle formation. Washington, DC, USA ACS Publ. American Chemical Society 2012 ACS nano 6 7 5791 5802 10.1021/nn301724z 2016-02-19 OPUS4-30194 Zeitschriftenartikel Wuithschick, M.; Paul, B.; Bienert, Ralf; Sarfraz, A.; Vainio, U.; Sztucki, M.; Kraehnert, R.; Strasser, P.; Rademann, K.; Emmerling, Franziska; Polte, J. Size-controlled synthesis of colloidal silver nanoparticles based on mechanistic understanding Metal nanoparticles have attracted much attention due to their unique properties. Size control provides an effective key to an accurate adjustment of colloidal properties. The common approach to size control is testing different sets of parameters via trial and error. The actual particle growth mechanisms, and in particular the influences of synthesis parameters on the growth process, remain a black box. As a result, precise size control is rarely achieved for most metal nanoparticles. This contribution presents an approach to size control that is based on mechanistic knowledge. It is exemplified for a common silver nanoparticle synthesis, namely, the reduction of AgClO4 with NaBH4. Conducting this approach allowed a well-directed modification of this synthesis that enables, for the first time, the size-controlled production of silver nanoparticles 4-8 nm in radius without addition of any stabilization agent. Washington, DC American Chemical Society 2013 Chemistry of materials 25 23 4679 4689 10.1021/cm401851g 2016-02-20 OPUS4-37235 Zeitschriftenartikel Kulla, Hannes; Greiser, Sebastian; Benemann, Sigrid; Rademann, K.; Emmerling, Franziska In Situ Investigation of a Self-Accelerated Cocrystal Formation by Grinding Pyrazinamide with Oxalic Acid A new cocrystal of pyrazinamide with oxalic acid was prepared mechanochemically and characterized by PXRD, Raman spectroscopy, solid-state NMR spectroscopy, DTA-TG, and SEM. Based on powder X-ray diffraction data the structure was solved. The formation pathway of the reaction was studied in situ using combined synchrotron PXRD and Raman spectroscopy. Using oxalic acid dihydrate the initially neat grinding turned into a rapid self-accelerated liquid-assisted grinding process by the release of crystallization water. Under these conditions, the cocrystal was formed directly within two minutes. 2016 Molecules 21 7 Article 917, 1 9 urn:nbn:de:kobv:b43-372357 10.3390/molecules21070917 http://creativecommons.org/licenses/by/3.0/de/deed.de 2016-08-31 OPUS4-31322 Zeitschriftenartikel Fischer, Franziska; Scholz, G.; Benemann, Sigrid; Rademann, K.; Emmerling, Franziska Evaluation of the formation pathways of cocrystal polymorphs in liquid-assisted syntheses The synthesis of the polymorphic cocrystal caffeine:anthranilic acid was investigated to obtain a better understanding of the processes leading to the formation of different polymorphic forms. In the case of these cocrystal polymorphs synthesized by liquid-assisted grinding a distinct influence of the dipole moment of the solvent was found. A pre-coordination between the solvent molecules and the caffeine:anthranilic acid cocrystal could be identified in the formation of form II. In the case of form II the solvent can be regarded as a catalyst. The formation pathway of each polymorph was evaluated using synchrotron X-ray diffraction. London, UK Royal Society of Chemistry 2014 CrystEngComm 16 35 8272 8278 urn:nbn:de:kobv:b43-313222 10.1039/c4ce00472h http://creativecommons.org/licenses/by/3.0/de/deed.de 2016-02-20 OPUS4-32090 Beitrag zu einem Tagungsband Meyer, Klas; Panne, Ulrich; Rademann, K.; Maiwald, Michael Quantitative NMR Spektroskopie unter Druck - Anwendungen an fluiden und gasförmigen technischen Mischungen Die quantitative NMR-Spektroskopie (qNMR) gewinnt in den letzten Jahren immer mehr an Bedeutung, speziell hinsichtlich der Anwendung auf komplexe Fragestellungen der analytischen Chemie. Ein großer Vorteil dieser Methode ist die Möglichkeit der Relativquantifizierung durch das „Zählen von Kernspins" in der Probe. Unter der Voraussetzung eines korrekt ausgeführten NMR-Experiments ist so der direkte Vergleich von Signalflächen im Spektrum möglich, ohne dass zuvor zwingend eine Kalibrierung notwendig ist. Bundesanstalt für Materialforschung und -prüfung (BAM) 2014 8. Interdisziplinäres Doktorandenseminar 978-3-9816380-1-1 8. Interdisziplinäres Doktorandenseminar Berlin, Germany 23.02.2014 25.02.2014 20 2016-02-20 OPUS4-21999 Zeitschriftenartikel Klimakow, Maria; Klobes, Peter; Thünemann, Andreas; Rademann, K.; Emmerling, Franziska Mechanochemical synthesis of metal-organic frameworks: A fast and facile approach toward quantitative yields and high specific surface areas The strategy of utilizing mechanochemical synthesis to obtain metal-organic frameworks (MOFs) with high surface areas is demonstrated for two model systems. The compounds HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate) and MOF-14 (Cu3(BTB)2, BTB = 4,4',4''-benzenetribenzoate) were synthesized by ball milling and characterized by powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal analysis (DTA/DTG/MS). The specific surface area (SSA) of both compounds was characterized by nitrogen adsorption. To verify these results and to understand how the synthetic conditions influence the pore structure and the surface area, additional small-angle X-ray scattering (SAXS) experiments were carried out. Our investigations confirm that this synthesis approach is a promising alternative method for distinct MOFs. This facile method leads to materials with surface areas of 1713 m²/g, which is comparable to the highest given values in the literature for the respective compounds. Washington, DC American Chemical Society 2010 Chemistry of materials 22 18 5216 5221 10.1021/cm1012119 2016-02-19 OPUS4-23872 Zeitschriftenartikel Simo, A.; Merk, Virginia; Fenger, R.; Kneipp, Janina; Rademann, K. Long-term stable silver subsurface ion-exchanged glasses for SERS applications We report on the formation of silver subsurface ion-exchanged metal oxide (silver SIMO) glasses and their surface-enhanced Raman scattering (SERS) activity. The samples were prepared by a combined thermal and chemical three-step methodology and characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), environmental electron scanning microscopy (ESEM), and UV/Vis spectroscopy. This unique method provides SERS substrates with protection against contamination and strong, reliable and reproducible SERS enhancement. The Raman enhancement factors of the long-term stable SIMO glasses were estimated to approximately 107. Weinheim Wiley-VCH 2011 ChemPhysChem 12 9 1683 1688 10.1002/cphc.201100098 2016-02-19 OPUS4-21396 Zeitschriftenartikel Klimakow, Maria; Leiterer, Jork; Kneipp, Janina; Rössler, E.; Panne, Ulrich; Rademann, K.; Emmerling, Franziska Combined synchrotron XRD/Raman measurements: In situ identification of polymorphic transitions during crystallization processes A combination of two analytical methods, time-resolved X-ray diffraction (XRD) and Raman spectroscopy, is presented as a novel tool for crystallization studies. An acoustic levitator was employed as sample environment. This setup enables the acquisition of XRD and Raman data in situ simultaneously within a 20 s period and hence permits investigation of polymorphic phase transitions during the crystallization process in different solvents (methanol, ethanol, acetone, dichloromethane, acetonitrile). These real time measurements allow the determination of the phase content from the onset of the first crystalline molecular assemblies to the stable system. To evaluate the capability of this approach, the setup was applied to elucidate the crystallization process of the polymorphic compound nifedipine. The results indicate the existence of solvent-dependent transient phases during the crystallization process. The quality of the data allowed the assignment of the lattice constants of the hitherto unknown crystal structure of the β-polymorph. Washington, DC American Chemical Society 2010 Langmuir 26 13 11233 11237 10.1021/la100540q 2016-02-19 OPUS4-21398 Zeitschriftenartikel Klimakow, Maria; Rademann, K.; Emmerling, Franziska Towards novel pseudo-polymorphs of nifedipine: elucidation of a slow crystallization process The crystallization of nifedipine was studied by means of synchrotron-X-ray diffraction, single-crystal X-ray structural analysis, and Raman spectroscopy. The results of slow evaporation (24 h in minimum) using dimethyl sulfoxide (DMSO) are presented. Since fast crystallization processes (typically minutes) in different solvents always led to the final formation of the thermodynamically most stable α-polymorph of nifedipine, we observed a novel pseudo-polymorph due to slow crystallization from DMSO. The single-crystal X-ray structure of the solvated species nifedipine·DMSO (1:1) is reported for the first time. In addition, the crystallization process on surfaces was followed by means of light microscopy and environmental scanning electron microscopy (ESEM) coupled with energy-dispersive X-ray spectroscopy (EDS) analysis. Different diffractions pattern and Raman spectra were observed for crystals grown from stock solution and those obtained by drying the solution on soda lime silicate surfaces. Washington, DC, USA American Chemical Society American Chemical Society 2010 Crystal growth & design 10 6 2693 2698 10.1021/cg100186v 2016-02-19 OPUS4-37744 Zeitschriftenartikel Fischer, Franziska; Wenzel, Klaus-Jürgen; Rademann, K.; Emmerling, Franziska Quantitative determination of activation energies in mechanochemical reactions Mechanochemical reactions often result in 100% yields of single products, making purifying procedures obsolete. Mechanochemistry is also a sustainable and eco-friendly method. The ever increasing interest in this method is contrasted by a lack in mechanistic understanding of the mechanochemical reactivity and selectivity. Recent in situ investigations provided direct insight into formation pathways. However, the currently available theories do not predict temperature T as an influential factor. Here, we report the first determination of an apparent activation energy for a mechanochemical reaction. In a temperaturedependent in situ study the cocrystallisation of ibuprofen and nicotinamide was investigated as a model system. These experiments provide a pivotal step towards a comprehensive understanding of milling reaction mechanisms. 2016 Physical Chemistry Chemical Physics 18 33 23320 23325 urn:nbn:de:kobv:b43-377444 10.1039/c6cp04280e http://creativecommons.org/licenses/by-nc/3.0/de/deed.de 2016-10-12 OPUS4-38097 Zeitschriftenartikel Fischer, Franziska; Lubjuhn, Dominik; Greiser, Sebastian; Rademann, K.; Emmerling, Franziska Supply and demand in the ball mill: competitive cocrystal reactions The stability of different theophylline cocrystals under milling conditions was investigated by competitive cocrystal reactions. To determine the most stable cocrystal form under milling conditions, the active pharmaceutical ingredient theophylline was either ground with two similar coformers (benzoic acid, benzamide, or isonicotinamide), or the existing theophylline cocrystals were ground together with a competitive coformer. All competitive reactions were investigated by in situ powder X-ray diffraction disclosing the formation pathway of the milling processes. On the basis of these milling reactions, a stability order (least to most stable) was derived: tp/bs < tp/ba < tp/ina < bs/ina. 2016 Crystal Growth & Design 16 10 5843 5851 10.1021/acs.cgd.6b00928 2016-11-03 OPUS4-38421 Zeitschriftenartikel Wilke, Manuel; Kabelitz, Anke; Gorelik, T. E.; de Oliveira Guilherme Buzanich, Ana; Reinholz, Uwe; Kolb, U.; Rademann, K.; Emmerling, Franziska The crystallisation of copper(II) phenylphosphonates The crystal structures and syntheses of four different copper(II) phenylphosphonates, the monophenylphosphonates α-, β-, and γ-Cu(O3PC6H5)·H2O (α-CuPhPmH (1) β-CuPhPmH (2) and γ-CuPhPmH (3)), and the diphosphonate Cu(HO3PC6H5)2·H2O (CuPhP2mH (4)), are presented. The compounds were synthesized from solution at room temperature, at elevated temperature, under hydrothermal conditions, and mechanochemical conditions. The structures of α-CuPhPmH (1) and CuPhP2mH (4) were solved from powder X-ray diffraction data. The structure of β-CuPhPmH (2) was solved by single crystal X-ray analysis. The structures were validated by extended X-ray absorption fine structure (EXAFS) and DTA analyses. Disorder of the crystal structure was elucidated by electron diffraction. The relationship between the compounds and their reaction pathways were investigated by in situ synchrotron measurements. The Royal Society of Chemistry 2016 Dalton Transactions 45 43 17453 17463 urn:nbn:de:kobv:b43-384217 10.1039/C6DT02904C http://creativecommons.org/licenses/by/3.0/de/deed.de 2016-11-24 OPUS4-34861 Zeitschriftenartikel Fischer, Franziska; Joester, Maike; Rademann, K.; Emmerling, Franziska Survival of the fittest: competitive co-crystal reactions in the ball mill The driving forces triggering the formation of co-crystals under milling conditions were investigated by using a set of multicomponent competitive milling reactions. In these reactions, different active pharmaceutical ingredients were ground together with a further compound acting as coformer. The study was based on new co-crystals including the coformer anthranilic acid. The results of the competitive milling reactions indicate that the formation of co-crystals driven by intermolecular recognition are influenced and inhibited by kinetic aspects including the formation of intermediates and the stability of the reactants. Weinheim Wiley-VCH Verl. 2015 Chemistry - A European journal 21 42 14969 14974 10.1002/chem.201500925 2016-02-20 OPUS4-38803 Zeitschriftenartikel Meyer, Klas; Rademann, K.; Panne, Ulrich; Maiwald, Michael Quantitative NMR spectroscopy for gas analysis for production of primary reference gas mixtures Due to its direct correlation to the number of spins within a sample quantitative NMR spectroscopy (qNMR) is a promising method with absolute comparison abilities in complex systems in technical, as well as metrological applications. Most of the samples studied with qNMR are in liquid state in diluted solutions, while gas-phase applications represent a rarely applied case. Commercially available NMR equipment was used for purity assessment of liquid and liquefied hydrocarbons serving as raw materials for production of primary reference gas standards. Additionally, gas-phase studies were performed within an online NMR flow probe, as well as in a high-pressure NMR setup to check feasibility as verification method for the composition of gas mixtures. 2017 Journal of Magnetic Resonance 275 1 10 10.1016/j.jmr.2016.11.016 2016-12-22 OPUS4-38472 Zeitschriftenartikel Fischer, Franziska; Greiser, Sebastian; Peifer, Dietmar; Jäger, Christian; Rademann, K.; Emmerling, Franziska Mechanochemically Induced Conversion of Crystalline Benzamide Polymorphs by Seeding Benzamide has been known for its polymorphism for almost 200 years.Three polymorphic forms are described. To date,itwas only possible to crystallizeametastable form in amixture together with the thermodynamically most stable form I. Acomplete transformation of form Iinto the metastable form III by mechanochemical treatment has been achieved. Catalytic amounts of nicotinamide seeds were used to activate the conversion by mechanochemical seeding. NMR experiments indicated that the nicotinamide molecules were incorporated statistically in the crystal lattice of benzamide form III during the conversion. The transformation pathway was evaluated using in situ powder X-ray diffraction. Weinheim WILEY-VCH 2016 Angewandte Chemie International Edition 128 46 14493 14497 10.1002/anie.201607358 2016-11-29 OPUS4-35491 Zeitschriftenartikel Wilke, Manuel; Klimakow, Maria; Rademann, K.; Emmerling, Franziska Fast and efficient synthesis of a host guest system: a mechanochemical approach An unusually fast and effective synthesis procedure for a host guest system consisting of a metal organic framework (MOF) and a polyoxometalate (POM) is described. The material was synthesised mechanochemically and the evolution of the structure was monitored ex and in situ using synchrotron X-ray diffraction (XRD). 2016 CrystEngComm 18 7 1096 1100 urn:nbn:de:kobv:b43-354910 10.1039/C5CE01868D http://creativecommons.org/licenses/by/3.0/de/deed.de 2016-03-16 OPUS4-35618 Zeitschriftenartikel Fischer, Franziska; Heidrich, Adrian; Greiser, Sebastian; Benemann, Sigrid; Rademann, K.; Emmerling, Franziska Polymorphism of mechanochemically synthesized cocrystals: a case study The liquid-assisted grinding cocrystallisation of theophylline with benzamide leading to polymorphic compounds was investigated. A solvent screening with seventeen different solvents was performed. The dipole moment of the solvent used in the synthesis determines the structure of the polymorphic product. A detailed investigation leads to the determination of the kinetically and thermodynamically favored product. In situ observations of the formation pathway during the grinding process of both polymorphs show that the thermodynamically favored cocrystal is formed in a two-step mechanism with the kinetic cocrystal as intermediate. American Chemical Society (ACS) 2016 Crystal Growth & Design 16 3 1701 1707 10.1021/acs.cgd.5b01776 2016-03-31 OPUS4-32583 Zeitschriftenartikel Gnutzmann, Tanja; Nguyen, Thi Yen; Rademann, K.; Emmerling, Franziska Solvent-triggered crystallization of polymorphs studied in situ The crystallization of a highly polymorphic compound was studied in situ by combined time-resolved X-ray diffraction and Raman spectroscopy. Any influences of solid surfaces, temperature, and humidity on the crystallization were omitted by the use of a specially designed acoustic levitator. Investigations of polymorphic phase transitions during the crystallization process in different solvents allowed a structure assignment from first crystalline assemblies to final crystalline form. For the first time, it was possible to yield pure phases of selected polymorphs of the model compound ROY (5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile) directly from solution. The influence of the solvent on the final products and transient phases during the crystallization process was elucidated. Washington, DC, USA American Chemical Society American Chemical Society 2014 Crystal growth & design 14 12 6445 6450 10.1021/cg501287v 2016-02-20 OPUS4-35136 Zeitschriftenartikel Nguyen, Thi Yen; Rademann, K.; Emmerling, Franziska Direct evidence of polyamorphism in paracetamol While polymorphism is a common phenomenon in the crystallization processes of organic compounds, polyamorphism has gained importance only recently. Using sophisticated sample environments and applying in situ scattering methods and vibrational spectroscopy, the complete crystallization process of organic compounds from solution can be traced and characterized. Diffuse scattering from amorphous intermediates can be investigated by analyzing the atomic pair distribution function (PDF) to gain further insights into molecular pre-orientation. The crystallization behavior of paracetamol was studied exemplarily under defined, surface-free conditions. Based on the choice of the solvent, the formation of different polymorphs is promoted. The thermodynamically stable form I and the metastable orthorhombic form II could be isolated in pure form directly from solution. For both polymorphs, the crystallization from solution proceeds via a distinct amorphous precursor phase. PDF analyses of these different amorphous states indicate a specific pre-orientation of the analyte molecules introduced by the solvent. The resulting crystalline polymorph is already imprinted in these proto-crystalline precursors. Direct experimental evidence for the polyamorphism of paracetamol is provided. London, UK Royal Society of Chemistry 2015 CrystEngComm 17 47 9029 9036 urn:nbn:de:kobv:b43-351366 10.1039/C5CE01583A http://creativecommons.org/licenses/by/3.0/de/deed.de 2016-02-20 OPUS4-48781 Zeitschriftenartikel Linberg, Kevin; Ali, Naveed Zafar; Etter, M.; Michalchuk, Adam; Rademann, K.; Emmerling, Franziska A Comparative Study of the Ionic Cocrystals NaX (α-d-Glucose)2 (X = Cl, Br, I) The mechanochemical formation of the ionic cocrystals of glucose (Glc) and sodium salts Glc2NaCl·H2O (1) and Glc2NaX (X = Br (2), I (3)) is presented. Products are formed by co-milling Glc with three sodium salts (NaCl, NaBr, NaI). The ionic cocrystals were obtained under both neat grinding and liquid-assisted grinding conditions, the later found to accelerate the reaction kinetics. The crystal structures of the ionic cocrystals (2) and (3) were solved from powder X-ray diffraction data. The structure solution contrasts with the structure of Glc2NaCl·H2O (1) where the electron density at three halide crystallographic sites is modeled as of being the intermediate between water molecule and a chloride ion. The reaction pathways of the three ionic cocrystals were investigated in real time using our tandem approach comprising a combination of in situ synchrotron powder X-ray diffraction and Raman spectroscopy. The results indicate the rapid formation of each cocrystal directly from their respective starting materials without any intermediate moiety formation. The products were further characterized by DTA-TG and elemental analysis. ACS Publications 2019 Crystal growth & design 19 8 4293 4299 10.1021/acs.cgd.8b01929 2019-08-29 OPUS4-48684 Zeitschriftenartikel Palantöken, Sinam; Bethke, K.; Zivanovic, V.; Kneipp, Janina; Rademann, Klaus; Kalinka, Gerhard Cellulose hydrogels physically crosslinked by glycine: Synthesis, characterization, thermal and mechanical properties Biopolymers are very efficient for significant applications ranging from tissue engineering, biological devices to water purification. There is a tremendous potential value of cellulose because of ist being the most abundant biopolymer on earth, swellability, and functional groups to be modified. A novel, highly efficient route for the fabrication of mechanically stable and natural hydrogels is described in which cellulose and glycine are dissolved in an alkaline solution of NaOH and neutralized in an acidic solution. The dissolving temperature and the glycine amount are essential parameters for the self-assembly of cellulose chains and for Tuning the morphology and the aggregate structures of the resulting hydrogels. Glycine plays the role of a physical crosslinker based on the Information obtained from FTIR and Raman spectra. Among the prepared set of hydrogels, CL5Gly30 hydrogels have the highest capacity to absorb water. The prepared CL5Gly30 gels can absorb up to seven times their dry weight due to its porous 3-D network structure. CL5Gly10 hydrogel exhibits 80% deformation under 21 N force executed. The method developed in this article can contribute to the application of heavy metal adsorption in aqueous solutions for water purification and waste management. USA Wiley 2019 Journal of Applied Polymer Science 136 48380, 1 11 urn:nbn:de:kobv:b43-486845 10.1002/APP.48380 https://creativecommons.org/licenses/by/4.0/deed.de 2019-08-13 OPUS4-39420 Zeitschriftenartikel Kulla, Hannes; Greiser, Sebastian; Benemann, Sigrid; Rademann, K.; Emmerling, Franziska Knowing When To Stop-Trapping Metastable Polymorphs in Mechanochemical Reactions The cocrystal formation of pyrazinamide (PZA) with malonic acid (MA) was studied in situ. The mechanochemical reaction proceeds via conversion of a crystalline intermediate (PZA:MA II) into the thermodynamically more stable form (PZA:MA I) upon further grinding. The information derived from in situ powder X-ray diffraction (PXRD) enabled the isolation of this new metastable polymorph. On the basis of the PXRD data, the crystal structure of the 1:1 cocrystal PZA:MA II was solved. The polymorphs were further characterized and compared by Raman spectroscopy, solid-state NMR spectroscopy, differential thermal analysis/thermogravimetric analysis, and scanning electron microscopy. Our study demonstrates how monitoring mechanochemical reactions by in situ PXRD can direct the discovery and isolation of even short-lived intermediates not yet accessed by conventional methods. 2017 Crystal Growth and Design 17 3 1190 1196 10.1021/acs.cgd.6b01572 2017-03-20 OPUS4-45672 Zeitschriftenartikel Wilke, Manuel; Akhemtova, Irina; Rademann, K.; Emmerling, Franziska Mechanochemical synthesis of cerium(IV)-phosphonates The syntheses and crystal structures of two cerium(IV) phosphonates are presented. Cerium(IV) bis(phenylphosphonate) Ce(O3PC6H5)2 1 can be formed from precipitation and mechanochemical reaction, whereas cerium(IV) bis(carboxymethylphosphonate) monohydrate Ce(O3PCH2COOH)2 H2O 2 is only accessible via ball milling. All reactions proceed very fast and are completed within a short time span. In situ measurements for the syntheses of 1 show that the product occurs within seconds or a few minutes, respectively. The structures were solved from powder X-ray diffraction data. Springer Science + Business Media B.V. 2018 Journal of materials science 53 19 13733 13741 10.1007/s10853-018-2507-x 2018-08-09 OPUS4-41490 Zeitschriftenartikel Wilke, Manuel; Kabelitz, Anke; Zimathies, Annett; Rademann, K.; Emmerling, Franziska Crystal structure and in situ investigation of a mechanochemical synthesized 3D zinc N-(phosphonomethyl)glycinate The mechanochemical synthesis of the zinc N-(phosphonomethyl)glycinate Zn(O₃PCH₂NH₂CH₂CO₂) H₂O is presented. The structure was solved from powder X-ray diffraction (PXRD) data. In the three-dimensional pillared structure, the Zn atoms are coordinated tetrahedrally. In situ investigations of the reaction process with synchrotron PXRD and Raman spectroscopy reveal a two-step process including the formation of an intermediate. New York Springer 2017 Journal of Materials Science 52 20 12013 12020 10.1007/s10853-017-1121-7 2017-08-22 OPUS4-41197 Zeitschriftenartikel Kulla, Hannes; Fischer, Franziska; Benemann, Sigrid; Rademann, K.; Emmerling, Franziska The effect of the ball to reactant ratio on mechanochemical reaction times studied by in situ PXRD The effect of the reactant powder mass on reaction times for the mechanochemical formation of a soft matter model system was studied by in situ PXRD. The syntheses were performed at a constant ball mass in a shaker mill with and without glassy SiO2 as an inert additive. Reaction times decreased with the increase of the ball to reactant ratio (BRR). The kinetic influence of the SiO2 powder was excluded. The decrease in the reaction time with decreasing mass of reactants was related to the rise in the stress energy transferred to the powder by a higher ball impact. The BRR had no effect on the induction time. But the product conversion was accelerated by raising the BRR. While a certain temperature is needed for the activation of reactants in the induction phase, the conversion of soft matter reactants is rather controlled by impact than temperature. 2017 Crystengcomm 19 28 3902 3907 10.1039/c7ce00502d 2017-08-07