Day 2 :
Keynote Forum
Richard M. Kellogg
University of Groningen, Netherlands
Keynote: Attrition-induced deracemization of racemizable crystal-liquid suspensions for the production of industrially relevant compounds
Time : 09:10-09:50
Biography:
Richard M. Kellogg was professor of chemistry at the University of Groningen in The Netherlands for 25 years. He co-founded the contract research organization Syncom BV for which he is still scientific advisor. He is also chief scientific officer of Philae Pharmaceuticals, a company devoted the use of RNA technology for the treatment of skin diseases.
Abstract:
It has been demonstrated that certain chiral racemic compounds sensitive to catalyzed racemization in solution, when subjected to strong grinding as suspensions, deracemize entirely. A strict additional requirement is that the compounds be conglomerates. How does this happen? It is thought that relatively rare primary nucleation of the racemic conglomerate provides a crystal that must have single handedness. Rapid secondary nucleation under conditions whereby growing crystals are continuously shattered leads to rapid propagation of that handedness. The process resembles closely Ostwald Ripening. The direction of deracemization can be determined by addition of a small amount of enantiomerically pure seed crystal. This process has been used to generate single enantiomers of commercially interesting compounds such as Naproxen, Clopidogrel and Prasugrel. Various extensions of this methodology have been developed and also methods for scale up have been developed both by us and by others.
Keynote Forum
Alexandre Urzhumtsev
Université de Lorraine, France
Keynote: Macromolecular computational crystallography: looking forward (and backward)
Time : 09:50 - 10:30
Biography:
Alexandre Urzhumtsev is a full professor at the Université de Lorraine, Nancy, and a researcher at the IGBMC, Illkirch, France. After the Kolmogorov’s physico-mathematical school-internat and the Faculty of Computational Mathematics at the Moscow State University, he moved to Pushchino, Russia, where he got his PhD in X-ray macromolecular crystallography. His main research interests are the development of computational methods and programmes for structure solution, refinement and validation, as well as solution of ‘difficult’ structures where development and application of original algorithms are required.
Abstract:
Addressing to more and more difficult problems of molecular structural biology requires development of new methodological, mathematical and computational tools. For macromolecular crystallography, that is one of the principal methods for the structure determination, the well-known lines of development are automation, structure analysis at very high and at very low resolutions, as well as model and data validation. Other developments are relevant to determination of very large or / and very flexible structures. There is also an evolution of crystallographic tools with a goal to apply them to non-crystallographic samples like isolated objects in XFEL or cryo electron microscopy images. In general, integration of other structural techniques with macromolecular crystallography is an onging process.rnrnWhile completely new and original ideas are required to go forward, some structural problems of macromolecular crystallography could be addressed by ‘recycling’ the tools and ideas known for a while. However, sometime their routine use may result in misleading or in meaningless results. This requires properly revisiting the corresponding tools and notions.rnrnThe talk will develop these issues illustrating them by several practical examples.rnrn
- Track 5: Crystallography in Materials Science
Location: Houston
Chair
Andriy Lotnyk
Leibniz Institute of Surface Modification, Germany
Session Introduction
Andriy Lotnyk
Leibniz Institute of Surface Modification, Germany
Title: Local atomic arrangement in Ge-Sb-Te phase-change thin films
Time : 10:50-11:15
Biography:
Andriy Lotnyk has completed his PhD in 2007 from the University of Halle working at the Max Planck Institute of Macrostructure Physics (Halle) and Post-doctoral studies from the same Institute. He has been a permanent staff member at the Faculty of Engineering, CAU of Kiel in 2009-2011. Presently, he is a group leader of the group “Structure Determination and Electron Microscopy” at the Leibniz Institute of Surface Modification (IOM). He was awarded by the Otto Hahn Medal from the Max Planck Society in 2008. He has authored and co-authored more than 50 scientific publications in peer reviewed journals and about the same number of conference papers.
Abstract:
Phase change materials (PCM), such as Te-based Ge2Sb2Te5 (GST), are known from optical memory applications and can be also used in non-volatile next generation random access memory. The relevant phases of GST are an amorphous phase, a metastable cubic rock salt like structure and a stable hexagonal layered structure. However, the atomic arrangements in the GST lattices are not well-understood and still under discussion. Insights into the local atomic arrangement of layered Ge-Sb-Te compounds are of particular importance from a fundamental point of view as well as for optical and electronic applications such as data storage, thermoelectric and ferroelectric. In this work, the local atomic arrangement in metastable GST and in Ge-Sb-Te thin films consisting of GST, Ge1Sb2Te4 and Ge3Sb2Te6 layered crystal structures are studied by using a combination of atomic-resolution aberration-corrected (Cs-corrected) high-angle annular dark-filed scanning transmission electron microscopy (HAADF-STEM) and detailed theoretical image simulation approaches. By comprehensive analyses of experimental and simulated HAADF-STEM image intensities, a structural model for metastable Ge2Sb2Te5 is proposed. In addition, the proper stacking sequences in the Ge-Sb-Te phases are determined. The obtained data are discussed with respect to existing experimental and theoretical structure models reported for bulk Ge-Sb-Te materials.
Christian Bonhomme
Pierre et Marie Curie University, France
Title: NMR crystallography: When nuclear magnetic resonance and diffraction meet
Time : 11:15-11:40
Biography:
Christian Bonhomme has completed his PhD from Pierre et Marie Curie University (UPMC) in Paris, France. Currently, he is full Professor at UPMC. He has been Invited Professor at the Department of Physics, Warwick University, UK. He is the leader of the SMiLES group at the Laboratoire de Chimie de la Matière Condensée de Paris. He has published more than 105 papers in reputed journals and has given 50 invited conferences in the fields of NMR, NMR Crystallography and Materials Science.
Abstract:
This presentation will expose an overview and the latest methodological developments in NMR Crystallography. Such a concept appeared recently in the solid state NMR community following the pioneering work of Pickard and Mauri and their implementation of the GIPAW method. Such a method allows the calculations of NMR parameters from first principles (at the DFT level) under periodic boundary conditions. Such calculations lead to full NMR tensorial parameters for all interactions (chemical shift, quadrupolar, J coupling, Knight shift) and for all nuclei described in the asymmetric unit of the crystal. GIAPW has been also extended to amorphous and disordered derivatives. The complementarity of diffraction techniques (X-rays and neutrons) and solid state NMR will be presented in the frame of NMR Crystallography. The goal of this approach is to propose new perspectives for the refinement of structures. The following questions will be raised: are NMR parameters sufficient for a full description of a crystal structure? Are a limited number of chemical environment representative of glassy architecture? A large panel of examples will illustrate the NMR Crystallography concept: inorganic structures, organic/inorganic hybrids, disordered materials such as biocompatible glasses doped with various cations. Applications of GIPAW will be presented as well in the frame of EPR and other spectroscopies.
Tamotsu Inabe
Hokkaido University, Japan
Title: Directionally tunable and mechanically deformable ferroelectric crystals from rotating polar globular ionic molecules
Time : 11:40-12:05
Biography:
Tamotsu Inabe has completed his PhD in 1981 from Hokkaido University, Japan, and Post-doctoral studies from Northwestern University (1981–1984). He is a full Professor from 1993 at the Division of Chemistry, Faculty of Science, Hokkaido University. He has published more than 250 papers mainly in the field of Solid-State Chemistry. He was honored A. K. Doolitle Award from A.C.S. and The Chemical Society of Japan Award for Creative Work. His research interest includes “Solid-state chemistry of molecular materials, crystal design, and electronic functional materials”.
Abstract:
Ferroelectrics are used in a wide range of applications, including memory elements, capacitors and sensors. Recently, molecular ferroelectric crystals have attracted interest as viable alternatives to conventional ceramic ferroelectrics because of their solution processability and lack of toxicity. Here, we show that a class of molecular compounds known as plastic crystals can exhibit ferroelectricity if the constituents are judiciously chosen from polar ionic molecules. The intrinsic features of plastic crystals, for example, the rotational motion of molecules and phase transitions with lattice-symmetry changes, provide the crystals with unique ferroelectric properties relative to those of conventional molecular crystals. This allows a flexible alteration of the polarization axis direction in a grown crystal by applying an electric field. Owing to the tunable nature of the crystal orientation, together with mechanical deformability, this type of molecular crystal represents an attractive functional material that could find use in a diverse range of applications.
Kosuke Suzuki
Gunma University, Japan
Title: Redox orbital and electronic structure in energy materials by Compton scattering spectroscopy
Time : 12:05-12:30
Biography:
Kosuke Suzuki has completed his PhD at Gunma University. His interest includes “Electronic structure of energy materials and Compton scattering technique”. He has published 29 papers in journals, proceedings and reports.
Abstract:
Compton scattering is one of the powerful tool for investigating electronic structure of the materials. Advantage of this technique is that Compton scattering use high-energy X-rays over 100 keV, which enables bulk sensitive measurement. Furthermore, Compton profile obtained from this technique reflects occupied orbitals of electrons upon Li insertion. We have applied this technique to electrode materials used for Li-ion battery, especially LixMn2O4 and LixCoO2. The Compton scattering experiments were performed on the BL08W beamline at the SPring-8 synchrotron facility in Japan. Results of our Compton profile measurement show an increment of itinerant electrons with Li insertion in both materials. By comparing experiment with first-principles calculations, we deduce that this increase of itinerant electrons has O 2p character. On the other hand, 3d orbitals of transition metals become less localized at the range of Li concentration corresponding to the optimal battery performance both for the LixMn2O4 and LixCoO2 cathodes. This 3d orbitals delocalization effect is associated with electron conductivity properties. Therefore, Compton scattering spectroscopy can provide new descriptors for electrode conductivity.
Srikanth Patala
North Carolina State University, USA
Title: Algorithms for generating coincidence site lattices (CSLs) and near-CSLs in arbitrary Bravais lattice systems
Time : 12:30-12:55
Biography:
Srikanth Patala received his BTech in Metallurgical and Materials Engineering from the Indian Institute of Technology Madras in 2005 and did his PhD in Materials Science and Engineering from the Massachusetts Institute of Technology in 2011. Prior to joining the NC State Faculty in 2013, he was a Post-doctoral Researcher in the Department of Materials Science and Engineering at Northwestern University. His research is focused on developing computational and analytical techniques to quantify the structure-property relationships in complex heterogeneous materials.
Abstract:
The formulation of coincidence site lattices (CSLs) has played a fundamental role in the analysis of interfaces in both experiments and simulations of inorganic materials systems. For example, the prediction of habit planes during precipitation and phase transformations relies on the determination of near-CSLs between the parent and the product lattice. The distributions of internal interfaces are generally analyzed as a function of their corresponding Σ-misorientations. Therefore, the ability, to automatically generate the Σ-rotations and their corresponding CSLs will not only enable the high-throughput prediction of interface structure-property relationships but will also help understand microstructure evolution during phase transformations. Grimmer, in a series of articles, has proposed the generating functions for determining the coincidence site lattices for cubic, hexagonal, trigonal and tetragonal Bravais lattices. These generated routines increased in complexity as the underlying symmetry of the lattice is reduced. In this talk, I will present a simple algorithm that computes all the unique CSL generating rotations for any Σ, and in arbitrary Bravais lattice systems. The algorithm involves two simple steps: (i) determination of all the unique sub-lattices of volume Σ; and (ii) the computation all the unique pairs of sub-lattices that are not related by the symmetry operations of the underlying crystals. I will also present strategies for extending this algorithm for computing near-CSL rotations between any two Bravais lattice systems (i.e. both homo-phase and hetero-phase interfaces).
Melanie John
Ludwig-Maximilians-Universität München, Germany
Title: Synthesis of (doped) ABO2 nanoparticles: Can this work at temperatures ≤90°C without using an additional reducing agent?
Time : 12:55-13:20
Biography:
Melanie John completed her BSc in Earth Sciences in 2012. She continued her studies in Geomaterials and completed her MSc in 2014. Within two years, she completed her PhD studies. She developed an environmental sustainable concept to extract heavy metals from aqueous solutions. At the same time, she created a new method to synthesize nanoparticles as delafossite and special core-shell composite materials at low temperatures <90°C. Now, she is continuing to widen her interdisciplinary research field. She published papers in reputed journals.
Abstract:
Delafossite (ABO2) is in focus of extensive research for its special magnetic, photo- and electrochemical as well as antiviral properties. Delafossite structures shows a wide variability of chemistry (A=e.g. Cu, Ag and B=e.g. Fe, Mn, Cr, Co, Al) and are used for diverse technical applications including catalysis, p-type conduction oxide, solar cells, or as luminescent material. Many physical properties are directly related to grain size, but most of the common synthesis routes as solid-state reactions, sol-gel or hydrothermal techniques lead to crystals in micron size. With the Lt-delafossite process, a new synthesis route by precipitation and subsequent ageing, it is possible to gain pure nano-sized delafossite at temperatures ≤90°C. The synthesized product exclusively consists of hexagonal, platy crystals with a diameter of less than 500 nm. The thickness increases with increasing ageing time from 5 to 200 nm. In case of CuFeO2, green rust (GR), precipitates first. Additional supply of OH- leads to the transformation of GR to delafossite. At the same time, GR acts as reducing agent for Cu2+. The ratio of 3R and 2H polytype is directly controllable by NaOH supply. The magnetic properties of CuFeO2 prepared by Lt-delafossite process deviate from both, natural delafossite and samples synthesized by other routes. A new approach is to produce doped delafossite. However, the incorporation of foreign ions is limited. Partly, they are adsorbed on the surface and so hinder crystal growth especially in [001]. Moreover it promotes twinning of the crystals.
Rajni Kant
University of Jammu, India
Title: Crystallographic and molecular packing interaction analysis of cholest-based steroids: A CSD study
Time : 14:20-14:45
Biography:
Rajni Kant completed his PhD from University of Jammu (India) in 1989 and Post-PhD from Oxford University (UK) during 1994-95. Presently, he is Professor of Physics at University of Jammu and also the Editor-in-Chief for Open Journal of Inorganic Chemistry (Scirp, USA). He has guided 21 PhD students, 48 MPhil students and has published over 350 research papers in journals of international repute. He has authored a book titled “Applied Solid State Physics”, published by Wiley-India Ltd.
Abstract:
Biological activity of steroids is one of the most important reasons for their synthesis and structural characterization. Cholestane (C27H48), the parent compound of all steroids, is obtained by the removal of hydroxyl group (from C3 position) and reduction of double bond (between C5 and C6 atoms) from the basic cholesterol nucleus. A total number of twenty-three structures of cholestane derivatives were obtained from the CSD for a comparative analysis of their crystallographic structures, computation of their possible biological activities and molecular packing interaction analysis. Intermolecular interactions of the type X-H…A [X=C,O, N; A=O, Cl, N, Br, F] have been analysed for a better understanding of molecular packing in cholestane class of steroids and discussed on the basis of distance-angle scatter plots. A careful examination of the entire interaction data reveals that the C-H…O hydrogen bonding is quite predominant in cholestane derivatives. The nature of the substituent at C3 position of the cholestane nucleus makes these molecules very interesting candidates for hydrogen bonding analysis. In most of the cases, the substituent at C3 position is primarily responsible for the occurrence of intermolecular hydrogen bonding in cholestanes. These substitutions are linked by intermolecular hydrogen bonding which in turn help to understand the dynamics of stacking interactions in supramolecular structures. Similar studies have also been carried out on various other classes of Cholest-based steroids, viz. Cholane, Pregnane, etc., to look for a possible solution to some of the following queries: (i) Could structural diversity in steroids be explored for a generalized crystallographic co-relations? (ii) Which of the X-H...A interactions (intra- or intermolecular) are dominant in various classes of steroids? (iii) Is there any preference of linearity for different hydrogen bonded interactions? Results of the emperical analysis of various kinds of cholest-based steroids as picked up from the CSD shall be presented.
Li-Xian Sun
Guilin University of Electronic Technology, China
Title: Synthesis and applications of porous materials for gas storage
Time : 14:45-15:10
Biography:
Li-Xian Sun has completed his PhD in 1994 from Hunan University and Post-doctoral studies from Jena University supported by Alexander Von Humboldt Fellowship and from National Institute of Advanced Industrial Science and Technology by NEDO fellowship. He is the Dean of School of Material Science and Engineering, Guilin University of Electronic Technology, Fellow of RSC (FRSC), Counsellor of International Association of Chemical Thermodynamics (IACT), Vice Chairman of of committee on Chemical Thermodynamics and Thermal Analysis of Chinese Chemical Society. He has published more than 300 papers in reputed journals and has been serving as a regional Editorial Board Member of Thermal Analysis & Calorimetry.
Abstract:
Studies of economic, highly efficient and safe gas storage materials (GSMs) are of great importance in the fuel cells based vehicles and CO2 capture. In our lab, we focus on studies on GSMs for H2 and CO2 based one micro/nano-technology. A series of metal organic frameworks (MOFs) and porous carbon materials such as grapheme for GSMs were synthesized. Their crystal structures, gas storage and thermodynamic properties were systematically evaluated. Furthermore, relationship of structure-activity were explored.
Myobin Jeon
Korea Advanced Institute Science and Technology, Republic of Korea
Title: Surfactant-mediated shape evolution of 3D organic molecular architecture
Time : 15:10-15:35
Biography:
Myobin Jeon has completed her Bachelor of Science in Chemistry from Pusan National University (PNU) in 2014. She is a student in the Intergrated Master’s & PhD Program at the Department of Chemitry from graduate schools at KAIST.
Abstract:
Systematic studies of the mechanism of the surfactant-controlled self-assembly of organic molecules are challenging in the field of crystal engineering and nanotechnology. Here, we discuss the shape evolution of three-dimensional molecular architectures (foldectures) formed from the self-assembly of a b-peptide foldamer. The evolution of the shape from a square plate to a square pyramid was observed, and the molecular packing structure was analyzed by diffraction experiments. This shape evolution arises from the passivation of the surfactants on the crystal facets and synergistic effect of their counterions. Moreover, we performed surface-energy calculations through a molecular dynamics simulation to demonstrate the roles of additives in the crystal growth mechanism. These findings would bolster our understanding of the interactions between surfactants and the interfaces of organic molecules and thus provide deeper insight into the design of functional organic materials.
Takahiro Sakagami
Ehime University, Japan
Title: A new approach for estimating the density of non-crystalline materials
Time : 15:55-16:20
Biography:
Takahiro Sakagami has received his Master of Science degree in Physics in 2010 from Ehime University. He has been working at AGC Techno Glass Co., Ltd since 2010. He has done his PhD course in the Department of Physics from Ehime University.
Abstract:
We propose a novel approach with which to estimate the density of liquids. The approach is based on the assumption that the systems would be structurally similar when viewed at around the length scale (inverse wavenumber) of the first peak of the structure factor, unless their thermodynamic states differ significantly. The assumption was implemented via a similarity transformation to the radial distribution function to extract the density from the structure factor of a reference state with a known density. The method was first tested using two model liquids (one is a simple liquid composed of the modified Lennard-Jones particles and the other is a molecular liquid composed of rigid tetrahedrons interacting via van der Waals forces), and could predict the densities within an error of several percent unless the state in question differed significantly from the reference state. The method was then applied to related real liquids, and satisfactory results were obtained for predicted densities. The possibility of applying the method to amorphous materials is shown, taking GeO2 glass as an exmaple. By choosing GeO2 at 8.5 GPa as a reference state, the method could satisfactorily reproduce the densities at higher pressures. The present method may thus pave the way for estimating density of high-density amorphous materials to which pycnometry is hardly applicable.
Janhavi Talegaonkar
Smt. P. K. Kotecha Mahila Mahavidyala, India
Title: Effect of change in structural properties on gas sensing performance of polyaniline-SrO2 nanocomposite
Time : 16:20-16:45
Biography:
Janhavi Talegaonkar is a Research Scholar and has completed her Master’s in Philosophy (2009), from North Maharashtra University, Jalgaon, (M.S.), India. Presently, she is an Assistant Professor in the Department of Physics, at Smt. P. K. Kotecha Mahila Mahavidyala, Bhusawal, (M.S.) India. She is pursuing PhD under the guidance of Prof. D. R. Patil. Her two papers have been published in reputed international journals.
Abstract:
Polyaniline is semi-crystalline polymer but it`s structure is studied rarely. Extensive study of synthesis, characterization and application of polyaniline and polyaniline-SrO2 composites has been carried out. Polyaniline having phenolic group as aromatic substituent and it`s nanocomposite samples with SrO2 were successfully fabricated by photo-induced polymerization method with various concentrations of SrO2. Prepared samples were then characterized by XRD, FTIR, SEM, EDAX, UV-Visible absorption spectra and gas sensing performance was checked for various gases. Parameters such as melting point, solubility, stability, morphology, electrical properties and hence gas sensing properties shows great dependence on crystal arrangement of organic component. Hence, crystal structure determination of newly developed component is very important. Analysis of XRD peaks of pure polyaniline and polyaniline-SrO2 composite exhibits structural change and percentage of crystallinity. Polyaniline-SrO2 composite exhibit tetragonal structure. The parallel and ordered package of pure polyaniline was studied from XRD peaks. FTIR peaks of polyaniline-SrO2 nanocomposite samples were taken to evaluate the interaction between polyaniline and SrO2 particles. As compare to pure polyaniline, UV-visible spectra of polyaniline-SrO2 nanocomposite shows shift towards lower wavelength. It indicates incorporation of SrO2 particles polyaniline matrix. Hence, exhibits surface:volume ratio. It reveals in improved electrical conductivity. Thermal conductivity exhibits positive temperature coefficient of resistor of prepared thick film of pure polyaniline and polyaniline-SrO2 nanocomposite. Gas sensing property of prepared samples was studied with respect to operating temperature, selectivity of CO2 against other gases response and recovery profile and long term stability of samples. As compare to pure polyaniline, change in structural properties of polyaniline-SrO2 nanocomposite shows enhanced performance for CO2 sensing.
Qixin Guo
Saga University,Japan
Title: Crystal growth of gallium oxide based wide bandgap semiconductors
Time : 16:45-17:10
Biography:
Prof. Guo received B. E., M.E., and Dr. E degrees in electronic engineering from Toyohashi University of Technology in Japan in 1990, 1992, and 1996, respectively. He is currently a Professor of Department of Electrical and Electronic Engineering, Saga University in Japan as well as Director of Saga University Synchrotron Light Application Center. His research interests include epitaxial growth and characterization of semiconductor materials. Prof. Guo has published more than 260 papers in scientific journals including Nature Communications, Advanced Materials, Physical Review B, and Applied Physics Letters.
Abstract:
The success in obtaining high quality β-Ga2O3 bulk substrates has positioned this material as a strong candidate for next-generation devices such as ultraviolet light emitting diode and photodetector. These achievements should be followed by bandgap engineering because it allows great flexibility in designing and optimizing the devices. A wider bandgap range is of great merit as it allows the design of devices such as high sensitive wavelength-tunable photodetectors, cutoff wavelength-tunable optical filters in more broad range. Al is a candidate to enlarge the bandgap of Ga2O3 because Al2O3 has a larger bandgap (~8.8 eV) and the similar electron structures of Al and Ga makes the alloy (AlGa)2O3 possible. In this work, we report on the crystal growth and characterization of (AlGa)2O3 films.We fabricated (AlGa)2O3 films on (0001) sapphire substrates by pulsed laser deposition using a KrF excimer laser source with wavelength 248 nm. The measurement of bandgap energies by examining the onset of inelastic energy loss in core-level atomic spectra using X-ray photoelectron spectroscopy is proved to be valid for determining the bandgap of (AlGa)2O3 films as it is in good agreement with the bandgap values from transmittance spectra. The measured bandgap of (AlGa)2O3 films increases continuously with the Al content covering the whole Al content range from about 5 to 7 eV. Recent progress on these materials will be presented.