Scientific Program

Conference Series Ltd invites all the participants across the globe to attend International Conference on Applied Crystallography Houston, Texas, USA.

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Day :

Track 1: Advanced Crystallography
Track 2: Crystallography in Biology
Track 6: Recent development in the X-ray studies
Track 7: Crystallography Applications

Location: Houston

Chair

Gerd Kaupp

University of Oldenburg, Germany

Oxygen-evolving complex (OEC) is the heart of photosystem II (PSII), which extracts electrons from water molecules using solar light energy in photosynthesis. Crystal structure of PSII has been resolved at a resolution of 1.9 Å (Umena, Kawakami, Shen and Kamiya, Nature (2011)), and chemical formula of OEC is fixed as Mn₄CaO₅ (H₂O)₄ for the first time. Based on the structural information (PDB-ID: 3WU2), researchers make efforts to elucidate the mechanism of oxygen-evolving reactions in OEC according to the Kok cycle model and to develop new catalysts for water splitting, which are required in artificial photosynthesis. Because OEC is highly sensitive to X-ray irradiation, however, X-ray reduction of OEC and structure change inductions have been discussed on the results from XAFS and DFT computational studies for the past five years. In order to overcome the X-ray reduction problem, we prepared highly isomorphous crystals of PSII and succeeded recently to collect two datasets of diffraction intensities at extremely low doses of 0.06 and 0.24 MGy (0.81 MGy for the previous dataset) at beamlines of SPring-8, BL38B1 and BL44XU. Obtained structures were compared with each other and with 3WU2, and two alternative structures of OEC were found in two monomers in an asymmetric unit of crystal. I will discuss in my talk about the meanings of the alternative structures and X-ray reduction effects on OEC

Jintaek Gong

Korea Advanced Institute Science and Technology, Korea

Title: Structure determination from powder diffraction data of self-assembled structures consisting of beta-peptide foldamers

Time : 16:20-16:40

Biography:

Jintaek Gong has received his Bachelor of Science degree (Magna Cum Laude) in Chemistry from the Korea Advanced Institute of Science and Technology (KAIST)in 2011. He is now pursuing his Integrated MSc and PhD Program in the Department of Chemistry. He has published seven papers in reputed journals and has served as a Powder Crystallographer in the Biomimetic Organic Laboratory of KAIST.

Abstract:

A well-designed beta-peptide foldamer can self-assemble to create various well-defined 3D architectures in aqueous solutions, named as foldecture. The term foldecture is combination of the words foldamer and architecture. Our group has reported unprecedented shapes of foldectures, such as a windmill and a molar tooth. These were highly homogenous both in terms of their size and in terms of morphology. Furthermore, to explore their potential use as functional materials, we recently published a study in which carboxyl groups were exposed to specific rhombic facets of foldectures. We found new potential capabilities of foldecture in relation to their mechanical properties as well as an anisotropic shape of a micro-sized container through the creation of a hollow cavity. Meanwhile, research on the functionalization of foldectures is expanding, as comprehending the self-assembly process and the resulting 3D shapes requires additional work. Hence, the structural determination of the molecular packing structure of foldecture is essential. In relation to this, the powder X-ray diffraction technique has been utilized here due to the dimensions and kinetically experimental conditions of foldecture. A PXRD analysis with synchrotron radiation was adequate to determine the packing structure with well-organized bonds and angle restraints. Further, it was able to designate the absolute orientation of the foldamers involved based on the predicted preferred orientation approximation. The use of a PXRD analysis on foldecture aided the understanding of the shape and properties of the newly formed foldecture and can be expected to play a major role in designing original examples of foldecture in the future.

Kakoli Bose

Tata Memorial Centre, India

Title: Structural insights into mode of regulation of serine protease HtrA2

Time : 15:55-16:20

Biography:

Dr. Kakoli Bose is Principal Investigator and Assistant Professor at ACTREC which is a premier organization of the country dedicated to cancer research and patient care. Dr. Bose completed her graduate studies at North Carolina State University, Raleigh and postdoctoral training at Tufts New England Medical Centre, Boston. Dr. Bose’s research interest focuses on non-classical mechanisms of programmed cell death with emphasis on understanding structure-function relationship of proteins involved in novel adapter-independent extrinsic pathways and caspase-independent apoptosis with the aim of targeting them for disease intervention.

Abstract:

High-temperature requirement protease A2 (HtrA2), a proapoptotic serine protease is involved in maintaining mitochondrial homeostasis. This multifaceted protein has been implicated in several diseases including cancer and neurodegeneration thus making it an important therapeutic target. HtrA2 comprises a short N-terminal region, a serine protease domain and regulatory PDZ (protein-protein interaction) domain. The complex trimeric structure, intricate PDZ-protease crosstalk, allosteric mechanism of activation that is mediated both through its N- as well as C-termini, and most importantly its involvement in both caspase-dependent as well as independent apoptotic mechanism has made this protease an important molecule for biomedical research. Unlike other members of the family, human HtrA2 has been found to be activated through its short N-terminal region in addition to the classical substrate/adapter binding pocket in the PDZ domain. Interaction with inhibitor of apoptosis proteins (such as XIAP) through its N-terminus, leads not only to subsequent cleavage of the molecule but also simultaneous activation of HtrA2, suggesting a ‘positive feedback’ mechanism. Similar mechanism is observed for PDZ-mediated substrate binding and activation as well. Therefore, understanding this complex mechanism and identifying the dual regulatory switch of its allosteric activation will help devise modulators with desired characteristics for therapeutic intervention against diseases it is associated with. It will also shed light on how point mutations lead to its inactivation as observed in diseases such as Alzheimer’s and Parkinson’s. Keeping these in mind, here we aim at understanding the structural correlates of mode of activation of HtrA2 and several pathogenic mutants (in complex with substrates) at atomic level using X-ray crystallography and biophysical probes

Geeta Hundal

Guru Nanak Dev University, India

Title: Hydrated nickel(II) ions: The new secondary building units for the formation of 2D and 3D cationic water networks

Time : 12:55-13:20

Biography:

Geeta Hundal has done her Ph. D from Guru Nanak Dev University in the field of small molecule crystallography. She did her post doctoral research for two years in the same field at CSIC, Rocasolano, Madrid, Spain and stayed in South Korea for two years as Brain-pool scientist in the Korean Research Institute of Chemical Technology She is presently a professor in the department of Chemistry, Guru Nanak Dev University, Amritsar, India. She has published 145 research papers in journals of international repute. Besides crystallography her other interesst are chemical sensing, supramolecular chemistry and coordination chemistry.

Abstract:

As supramolecular assemblies, water molecules may just act as fillers by accommodating the interstitial voids or be a part of the self-assembled architecture themselves. The inter- and intramolecular H-bonds in various water clusters have been found to lie between -9 and -32 kJ mol^-¹ and -10 to -100 kJ mol^-¹, respectively, and for both, the data invariably depends on the O···O cutoff being considered. Therefore, the major role of understanding water cluster chemistry is played by X-ray crystallography. One of the aims of these structural studies on water clusters has been to accurately characterize them as various structural motifs. We have found that [Ni(H₂O)₆]²⁺ has the ability to form self-assembled supramolecular structures with lattice water molecules and demonstrate yet another unique modes of the cooperative association of water molecules, forming 2D and 3D cationic layers of water molecules. The anions are forming either alternate H-bonded layers with the 2D water layers or are sitting in the huge channels present in the open 3D network of water molecules. Such structural studies are helpful in understanding the nature and role of various water clusters in biological systems, where assorted metal ions are involved in diverse biological functions in an aqueous environment.

Break: Lunch break 13:20-14:20 @ Churchill

Dilano K Saldin

University of Wisconsin, USA

Title: Structure determination by correlated scattering

Time : 15:10-15:35

Biography:

D K Saldin has completed his DPhil from the University of Oxford, UK. After some Post-doctoral work at Oxford, he took up a position of a Research Fellow at Imperial College, London from 1981-1988. In 1988, he joined the Physics department of the University of Wisconsin-Milwaukee, where he currently holds the title of a Distinguished Professor.

Abstract:

In general what are measured on X-ray scattering are the intensities of X-rays. What is more if the scattering units are all identical and identically oriented; a measurable intensity is found from the unit cell even with relatively weak X-rays. Ingenious methods have been devised in X-ray crystallography for deducing the phases of the scattered X-rays and consequently the amplitudes of scattering. A Fourier transform of the scattered amplitudes gives the electron density of the unit cell and this often allows the structure to be deduced. The advent of the new X-ray sources such as those from an X-ray free electron laser (XFEL) allows a paradigm shift for the measurement of molecular structure. The increase in intensity of 10 billion-fold allows the possibility of structure determination even if proteins do not form crystals by scattering of individual molecules. A translation of the molecule gives rise to exactly the same intensities, but as rotation in general changes the intensities totally. However, even in the case of rotation a quantity called the angular correlations, while dependent on the structure, do not depend on the state of rotation or translation and is thus, ideally placed to allow structure determination of molecules typically injected into an XFEL in the form of particles of constant structure but unknown orientation or position. What is more, the absence of translational periodicity as in a crystal, allows the determination of the phases of the scattered amplitudes by an iterative phasing algorithm. We will discuss the use of angular correlations to determine the structures of proteins and viruses, with an XFEL.

Break: Networking and Refreshments Break 15:35-15:55 @ Foyer

HÃ©lÃ¨ne DÃ©mÃ©nÃ©

Centre de Biochimie Structurale, France

Title: Structural insights into the activation process of the opioid mu receptor

Time : 14:20-14:45

Biography:

Hélène Déméné has completed her PhD from Université Paris six and Post-doctoral studies at the Mount Sinai Hospital (New York, US) and at the Institut de Biologie Structurale (Grenoble, France). She is now Research Associate at the Centre of Biochimie Structrale (Montpellier, France) where she specialized in the Structural Biology of GPCRs. She has published more than 25 papers in reputed journals.

Abstract:

Opioid receptors (OR), members of the G protein-coupled receptor (GPCR) superfamily, constitute the major target for the treatment of pain. The use of opioid drugs acting at these receptors is however a leading cause of death by overdose in Europe and North America. Our collaborators recently described the structure of an antagonist-bound inactive and agonist bound conformation of the µOR. It demonstrated the key molecular determinants for ligand binding and activation process common to other GPCRs. However, much remains to be learned about the mechanisms by which different agonists can induce distinct levels of Gi protein activation and/or arrestins recruitment upon activation of µOR. Pharmacological and biophysical studies suggest that this versatility can be achieved through the structural plasticity of GPCRs. In this work, we analyse the conformational landscape of the µOR in distinct pharmacological conditions (full and partial agonists, antagonist) using liquid-state NMR spectroscopy in light of the X-ray structures. We also investigate the structure and dynamics changes upon binding the effector Gs protein and a mimetic nanobody thereof. Our results show that there is very weak allosteric coupling between the agonist binding pocket and G protein coupling interface. Furthermore, the analysis provides clues on the successive structural events leading to the full active conformation of mOR. We can extend this approach to biased ligands that are able to elicit G-protein activation without arrestin activation. A better knowledge of the structural basis of all activation pathways for opioid drug efficacy may lead to new therapeutic approaches with limited side effects.

Mandeep Sekhon

University of California, USA

Title: Numerical simulation of liquid phase diffusion growth of SiGe single crystals using fixed and dynamic grid techniques: A comparison

Title: Transport property measurements on tungsten diselenide single crystals doped by copper

Track 1:Advanced Crystallography
Track 7: Crystallography Applications

Location: Houston

Session Introduction

Victor Ovcharenko

International Tomography Center, Russia

Title: Breathing crystals - P,T-Induced dynamics of heterospin crystals

Biography:

Abstract:

The results of studies of magnetostructural correlations inherent in heterospin coordination compounds of transition metals with stable nitroxides were discussed. When the temperature changes, the compounds undergo structural rearrangements accompanied by magnetic effects similar to spin crossover. The magnetic effects that appear as a result of the structural rearrangement of the crystal are determined by the spatial dynamics of the coordination units containing exchange clusters {Jahn-Teller metal ionâ€“coordinated organic radical} and generally involve considerable changes in the crystal volume during repeated cooling-heating cycles. Mechanical stability of heterospin crystals capable of being reversibly compressed and expanded during multiple crossing of the temperature range of the phase transition region is reflected by the term "breathing crystals." The plasticity of the single crystals allows studies of reversible SCâ€“SC phase transformations over a wide temperature range (30â€“300 K), the creation of X-ray cinema, and analysis of structural transformations in the four-dimensional space (coordinates + temperature). The report discusses methods of control over the character and temperature of spin transition for compounds from this class. The effect of a change in the external pressure on the character of the temperature dependence of the effective magnetic moment was also discussed. The phase transformation of the heterospin compound caused by its cooling may be accompanied by deep coloring of the solid phase, which is an unusual effect. The possibility of creating spin devices whose working mechanism (unit) is an exchange cluster that changes multiplicity under the action of temperature, pressure, or light was discussed.

Yanli Wang

Chinese Academy of Sciences, China

Title: Structure-based mechanistic insights into PAM-dependent spacer acquisition for incorporation into the CRISPR array

Biography:

Yanli Wang has completed her PhD fromUniversity of Science and Technology of China and postdoctoral studies from Memorial Sloan-Kettering Cancer Center. She is a principle investigator of Institute of Biophysics, Chinese Academy of Sciences. She has published more than 25 papers in reputed journals and has been serving as an editorial board member of Non-Coding RNA.

Abstract:

Bacteria obtain a memory of viral invaders by incorporating their DNA sequence elements into the host CRISPR locus, generating a new 33-nt spacer within the CRISPR array. We report on the crystal structure of a Cas1-Cas2-dual-forked DNA complex in efforts towards understanding how the protospacer is selected for insertion into the CRISPR locus. Our structure of the complex reveals a protospacer DNA containing a 23-bp duplex bracketed by tyrosine residues, together with anchored flanking 3â€™-overhang segments. The complementary PAM sequence in the 3â€™-overhangs are recognized by Cas1a catalytic subunits in a base-specific manner for protospacer selection and subsequent cleavage at positions 5-nts from the duplex boundary, thereby generating a 33-nt DNA intermediate for incorporation into the CRISPR array. Upon protospacer binding, the Cas1-Cas2 complex undergoes a significant conformational change, generating a flat surface conducive to proper protospacer recognition. Overall, our studies reveal unanticipated structure-based mechanistic insights into PAM-dependent spacer acquisition.

Geeta Hundal

Guru Nanak Dev University, India

Title: Hydrated nickel(II) ions- the new secondary building units for the formation of 2D and 3D cationic water networks

Biography:

GH has done her Ph. D from Guru Nanak Dev University in the field of small molecule crystallography. She did her post doctoral research for two years in the same field at CSIC, Rocasolano, Madrid, Spain and stayed in South Korea for two years as Brain-pool scientist in the Korean Research Institute of Chemical Technology She is presently a professor in the department of Chemistry, Guru Nanak Dev University, Amritsar, India. She has published 145 research papers in journals of international repute. Besides crystallography her other interesst are chemical sensing, supramolecular chemistry and coordination chemistry.

Abstract:

As supramolecular assemblies, water molecules may just act as fillers by accommodating the interstitial voids or be a part of the self-assembled architecture themselves. The inter- and intramolecular H-bonds in various water clusters have been found to lie between âˆ’9 and âˆ’32 kJ molâˆ’1 and âˆ’10 to âˆ’100 kJ molâˆ’1, respectively, and for both, the data invariably depends on the OÂ·Â·Â·O cutoff being considered. Therefore, the major role to understanding water cluster chemistry is played by X-ray crystallography.One of the aims of these structural studies on water clusters has been to accurately characterize them as various structural motifs. We have found that [Ni(H2O)6]2+ has the ability to form self-assembled supramolecular structures with lattice water molecules and demonstrate yet another unique modes of the cooperative association of water molecules, forming 2D and 3D cationic layers of water molecules. The anions are forming either alternate H-bonded layers with the 2D water layers or are sitting in the huge channels present in the open 3D network of water molecules. Such structural studies are helpful in understanding the nature and role of various water clusters in biological systems, where assorted metal ions are involved in diverse biological functions in an aqueous environment.

A. Thalal

Cadi Ayyad University, Morocco

Title: Symmetry in art and architecture of the western islamic golden age

Biography:

Abdelmalek THALAL completed his doctorate at the age of 31 years from Pierre and Marie Curie University (Paris) and Postdoctoral Studies from the Centre for Nuclear Energy (Grenoble). He obtained the PhD Prize awarded by the French National Centre for Scientific Research. He is professor of physics at the University Cadi Ayyad (Marrakech) and leads the research group "application of crystallography to the Moroccan geometric art". He has published over 25 articles and organized more than ten international meetings among which the European Crystallographic Meeting (Marrakech - 2007). He was member of several international scientific committees, leaded the project of the International Year of Crystallography (2014) and co-organized the closing IYCr2014.

Abstract:

Throughout history there were always links between geometry and art. These links become especially evident when to the study of ornamental art, we apply the theory of symmetry. The idea to study ornaments of different cultures from the point of view of the theory of symmetry, given by G. PÃ³lya (1924) and A. Speiser (1927), was supported by the intensive development of the theory of symmetry in the 20th century. This work is dedicated to the symmetry in the ornamental art of the western Islamic. Moorish craftsmen developed an original, rich and varied art, which integrated the geometry in the construction of complex patterns. This art which flourished in Andalusia until the 15th century and continues to develop until now in North Africa, has evolved over the centuries involving symmetry in its most general sense: harmony, order, consistency and invariance. The ornamental periodic motifs that adorn buildings which will be discussed, from the standpoint of the theory of symmetry, existed long before Fedorov (1891), showed that there are only 17 periodic tilings of the plane. In the other hand, quasiperiodic tiling discovered by D. Shechtman (1984), adorn the ancient building in the western Islamic world. The similarity between the patterns and quasicrystals, aroused the interest of several crystallographers. Some examples of quasiperiodic patterns found in several Moroccan historical building will be described in term of Penrose tiling and give new quasiperiodic patterns obtained by Aboufadil et al using the multigrid method (2014).

Seyfan Kelil Shukri

Addis Abeba University, Ethiopia

Title: Charge transport properties in disordered organic semiconductor as a function of charge density: Monte carlo simulation

Biography:

Seyfan Kelil has completed his Msc at the age of 25 years from Addis Abeba University and Currently he is PhD student at Addis Abeba University. He is the lecture of Jigjiga University departement of physics

Abstract:

We have done Kinetic Monte Carlo (KMC) simulations to investigate the effect of charge carrier density on the electrical conductivity and carrier mobility in disordered organic semiconductors using a lattice model. The density of state (DOS) of the system are considered to be Gaussian and exponential. Our simulations reveal that the mobility of the charge carrier increases with charge carrier density for both DOSs. In contrast, the mobility of charge carriers decreases as the disorder increases. In addition the shape of the DOS has a significance effect on the charge transport properties as a function of density which are clearly seen. On the other hand, for the same distribution width and at low carrier density, the change occurred on the conductivity and mobility for a Gaussian DOS is more pronounced than that for the exponential DOS.

Track 2: Crystallography in Biology

Location: Houston

Session Introduction

Lou Massa

Hunter College, & the Graduate Center CUNY, USA

Title: A new understanding in context of X-ray quantum crystallography (QCr) and the kernel energy method (KEM)

Claudia is a PhD student, completed her master in Molecular Biology at the Brasilia's university in 2014. She has participated in several national and international congresses and conferences. He has experience in the area of molecular biology, acting on issues such as cloning and gene expression, molecular biology of human pathogenic fungi, production of recombinant proteins, enzymatic assays, protein crystallography and in vitro testing of potential antifungal drugs.

Abstract:

Although fungal infections contribute substantially to human morbidity and mortality, the impact of these diseases on human health is not widely appreciated. Cryptococcosis is caused by Cryptococcus neoformans, an encapsulated fungus that causes lung disease and can spread widely in the brain and skin, affects about one million people each year and kills about 650,000. The virulence of this fungus is mediated by several factors, the antioxidant defense mechanisms have been shown to be important not only for resistance to reactive species but also for survival in the mammalian host. These antioxidant enzymes important for virulence may serve as excellent targets for antifungal therapy. The classical thioredoxin system is formed by thioredoxin reductase and its characteristic substrate the redox active protein thioredoxin, whose reduction is supported by NADPH. Thioredoxins are low molecular weight proteins that can be localized in the cytoplasm, in the mitochondria as well as in the extracellular space. Trx possess an active site made up of two cysteines in a conserved motif, CXXC, which is highly conserved. In this study, heterologous expression, purification, enzymatic characterization and crystallographic structure of oxidized Trx1 has been solved at 1.8Ã… resolution in the fungal pathogen C. neoformans. For crystallization assays, Trx1 has been concentrated to 9 mg mL-1 in 1,7 M Ammonium sulfate and 0,02 M Tris hydrochloride pH 8,5, the crystallization trials have been performed using the hanging-drop vapor diffusion method. X-ray diffraction data were collected using a synchrotron radiation source and the structure was solved by molecular replacement and refined to a crystallographic R factor of 15.0% and a free R factor of 19%.

Juliane Fonseca de Oliveira

University of Porto, Portugal

Title: Dimensionality of pattern formation in symmetric physical systems

Biography:

Juliane Oliveira has completed her B.S. in Mathematics from Federal University of Bahia (UFBA), Brazil, with final work related to studies of Einstein equation on Flag Manifolds. She is currently a PhD student in the Department of Mathematics at University of Porto, working in Bifurcation and Crystallography Theory. In particular, she wants to describe a mathematical tool in order to understand the transition of dimensionality in Reaction Diffusion systems in the Turing instability regime.

Abstract:

In the study of pattern formation in symmetric physical systems a 3-dimensional structure in thin domains is often modelled as 2-dimensional one. As a contrast, in this talk we use the full 3-dimensionality of the problem to give a theoretical interpretation and possibly decide whether the pattern seen in such systems naturally occur in either 2- or 3- dimension. For this purpose, we are concerned with functions in 3-dimention that are invariant under the action of a crystallographic group and the symmetries of their projections into a function defined on a plane. In particular, we introduce a formalism to explain how the study of bifurcation theory, in the context of symmetries, is applied to the theory of projection we present.

Track 3: Chemical Crystallography

Location: Houston

Session Introduction

Boniface P. T. Fokwa

University of California-Riverside, USA

Title: Magnetic ordering, frustration and possible spin liquid state from 1D Cr3-triangles in the TiCrIr2 xOsxB2 series

Title: A coordination polymer with lewis acid sites for capture of aromatic N-donors ligands and cyanide based on Zn(II) 1,4-benzenedicarboxylate

Biography:

Alejandro Dorazco was born in Mexico. He joined at Center of Sustentable Chemistry CCQIS at National University Autonomous of Mexico (UNAM) in 2013 as full-time Associate Researcher. He obtained his Ph. D. in 2010 with a thesis in the field of Supramolecular Chemistry in the group Prof. Anatoly Yatsimirsky at UNAM, subsequently, he joined the group of Prof. Kay Severin, Swiss Federal Institute of Technology in Lausanne, as a postdoctoral fellow. In 2013, he started independent research projects focused on luminescent chemosensors, Supramolecular Chemistry and Crystal Engineering

Abstract:

The development of selective crystalline materials for capture of aromatic organic N-donors ligands and cyanide anion is a current topic in material sciences, environmental monitoring, quality control of water sources and supramolecular chemistry. Capture and store of low-weight chemical species (mainly gases) by mesoporous coordination polymers (CPs) based on metal-benzene multi carboxylate compounds has been studied thoroughly in the past few decades, this approach need CPs with large pores and frequently is not feasible preparing them into medium and large-scale by their chemical instability to hydrolysis or releasing molecules solvents which results in loss of the tridimensional structure and capture properties. In principle a stable molecular container for amines or cyanide can be achieve with CPs containing Lewis acid sites such as Zn(II) or Cd(II) with available coordination sites initially occuped by solvent molecules as DMF which provide structural and chemical stability and they may be replaced by ligands with higher affinity for the metal center as quinoline, pyridine and cyanide, without need to large pores. In this way, an 1D dinuclear coordination polymer [Zn2(1,4-BDC)2(DMF)2] (1) (1,4-benzenedicarboxylate) was synthesized and studied as molecular receptor for pyridine, quinoline, isoquinoline and cyanide from solutions of N-donors containing crystals of (1). Solid state transformations of crystals of (1) by partial exchange of solvent molecules with quinoline and isoquinolin was observed after of 24 h. at room temperature, on the other hand, cyanide and pyridine completely displace DMF molecules of (1) after 24 h. Releasing of DMF molecules was observed by 1H NMR measurements and the precence of isoquinoline, pyridine and cyanide in treated solid samples of (1) was detected and quantified by solid state 13C CP/MAS NMR, TGA, DSC and IR experiments. X-ray single crystal structures of [Zn2(1,4-BDC)2(isoquinoline)2] (2) and [Zn(1,4-BDC)(Py)2] (3) supports the captura of N-donors involving the coordination bond of nitrogen atom to metal center. From spectroscopic studies the affinity order of [Zn2(1,4-BDC)2(DMF)2] (1) to guest molecules was defined as CN- > Py > isoquinoline >> quinoline. Solid state transformations, structural and spectroscopic studies will be discussed in the presentation.

S.Kalainathan

VIT University, India

Title: Structural and optical properties of 2-[2-(2,4-Dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DBSI) and 1-Ethyl -2-[2-(4-hydroxy-phenyl)-vinyl]- pyridinium iodide (HSPI)

Biography:

Kalainathan Sivaperuman earned his doctorate in Physics from Anna University, Chennai, in 1992. At present, he is the Senior Professor and Deputy Director, Centre for Crystal Growth, VIT University, Vellore. So far he has produced 16 Ph.Dâ€™s and 10 M.Philâ€™s. At present, 6 scholars are working towards their Ph.Ds under his guidance. He has a total of 24 years of research experience in the field of Crystal Growth and he is the principal investigator of ongoing funded projects. He has published more than 160 papers in reputed journals. He has awarded Prof.P.Ramasamy National Award for Crystal Growth in 2009 by IACG.

Abstract:

The search and design of highly efficient organic nonlinear optical (NLO) single crystals are extremely important for the present day technological requirements. We present two D-Ï€-A organic core structures leading to highly efficient nonlinear optical (NLO) single crystals, 2-[2-(2,4-Dimethoxy-phenyl)-vinyl]-1-ethyl-pyridinium iodide (DBSI) and 1-Ethyl -2-[2-(4-hydroxy-phenyl)-vinyl]- pyridinium iodide (HSPI). Single crystals of the above two materials were successfully obtained from the methanol-acetonitrile mixed solvent by slow evaporation method. Single crystal X-ray diffraction analysis revealed that both the crystals crystallized in centrosymmetric crystal system with a triclinic space group PÄ« and monoclinic space group C2/c. Theoretical calculations were performed to derive HOMO-LUMO energies and dipole moment by using Spartonâ€™14 V1.0.1 program. The actual composition and the expected functional groups have been identified by 1H NMR and FTIR analysis. The optical transmittance window and band gap were ascertained by UV- Visible -NIR studies. Thermal studies exhibited that the grown crystals were thermally stable up to 232.5oC and 226.6oC. The surface features of the grown crystal were assessed by using an optical microscope. The dielectric studies were performed. Laser-induced surface damage and mechanical stability of grown crystal were studied to explore its suitability towards device fabrications. The third-order nonlinear optical susceptibility was derived from Z-scan technique, and it was found to be 1.020 x 10-3 esu (DBSI) and 4.40 x10-4 esu (HSPI) respectively, which is appreciably higher than some reported stilbazolium derivatives. All these obtained results in the present work making it an attractive candidate for NLO applications such as electro-optics and THz-wave generation.

Marietjie Schutte-Smith

University of the Free State, South Africa

Title: The Investigation of chemical crystallography and kinetic reactivity of Re(I) tricarbonyl complexes

Biography:

Marietjie Schutte-Smith has completed her PhD at 28 years of age at the University of the Free State, Bloemfontein, South Africa. She was appointed as a lecturer immediately after the completion of her PhD from 2012 and were promoted to senior lecturer in 2016. At the age of 33 she is supervising two MSc and six PhD students and she has published 21 articles.

Abstract:

The coordination chemistry of rhenium and technetium has gained major interest for the possible use in radiopharmacy, due to several favorable properties. A number of fac-[M(CO)3]+ (M = Re, 99mTc) type complexes have been synthesized to date with a large number of ligand systems. The three labile aqua ligands on the starting synthon fac-[Re(CO)3(H2O)3]+ can easily be substituted by a variety and/or combinations of ligands producing stable compounds and potential radiopharmaceuticals with many different characteristics. We focus on the fac-[Re(CO)3]+ moiety and related compounds by adopting the [2+1] approach. The solid state behaviour and the effects like the charge, the donor atoms and electron donating and withdrawing effects of the ligands coordinated to the metal are explored. The influence of the coordinated bidentate ligands on the rate of substitution by a variety of entering ligands in solution is also investigated. The aqueous kinetics of fac-Re(I) tricarbonyl complexes are virtually unexplored. We synthesized a water soluble complex which allowed us to evaluate the reactivity of a fac-Re(I) tricarbonyl type complexes in aqueous medium which is imperative for biomedical application. The first high pressure substitution kinetics on a fac-[Re(L,Lâ€™-bid)(CO)3(CH3OH)] complex are also reported here.

Track 6: Recent development in the X-ray studies

Location: Houston

Session Introduction

Borislav Angelov

Czech Academy of Sciences, Czech Republic

Title: Recent advances and perspectives in fast time-resolved X-ray crystallography of proteins

Biography:

Dr. Borislav Angelov has completed his PhD study at the Bulgarian Academy of Sciences (Sofia, Bulgaria). He performed postdoctoral research work at the Helmholtz Centrum Geesthacht (Hamburg area, Germany) and the University of Aarhus (Denmark) before his appointment at the Czech Academy of Sciences. Dr. Angelov is a Senior scientist at the ELI beamlines, Institute of Physics of the Czech Academy of Sciences. He has published more than 50 papers in international journals and has experience in structure analysis from more than 15 large scale user facilities worldwide.

Abstract:

The purpose of this work is to outline the new developments and perspectives for time resolved X-ray scattering and diffraction analysis on a time scale from femtoseconds to milliseconds. The utilization of femtosecond laser pulses for the generation of X-rays has opened new opportunities for structural studies of fast kinetic processes. This new technology is essentially different from the operation principles employed at the synchrotron sources and the free electron lasers. The ELI beamlines facility is planned to start operation by the end of 2016 near Prague in Czech Republic. It will provide unique advantages for time-resolved crystallography based on laser-driven plasma X-Ray Source (PXS). The generated pulses will span approx. 100 fs with a repetition rate of 1 kHz. The scattered and diffracted X-rays by the sample will be counted using a Dectris Eiger 1M area detector, which operates at the same frame rate as the source, i.e. 1 kHz. The created setup can be combined with several pump probe lasers in order to study the fast kinetics of dynamic biological systems, for example the protein photo systems. Under the conditions of low flux, the generation of a crystallographic image requires several pulses to be obtained. Therefore, serial femtosecond crystallography at tabletop XPS sources is becoming feasible.

D. K. Saldin

University of Wisconsin-Milwaukee, USA

Title: Structure determination by correlated scattering

Biography:

Dilano Saldin has completed his D. Phil. From the University of Oxford in the UK, After some postdoctoral work at Oxford, he took up a position of Reserch Fellow at Imperial College.London from 1981-1988. In 1988 he joined the Physics Departtment of the University of Wisconsin-Milwaukee, where he now holds the title of Distinguished Professor.

Abstract:

In general what is measured on x-ray scattering are the intensities of x-rays. What is more if the scattering units are all identical and identically oriented, a measurable intensity is found from the unit cell even with relatively weak x-rays. Ingenious methods have been devised in x-ray crystallography for deducing the phases of the scattered x-rays and consequently the amplitudes of scattering. A Fourier transform of the scattered amplitudes gives the electron density of the unit cell and this often allows the structure to be deduced. The advent of the new x-ray sources such as those from an x-ray free electron laser (XFEL) allows a paradigm shift for the measurement of molecular structure. The increase in intensity of ten billion-fold allows the possibity of structure determination even if proteins do not form crystals by scattering off individual molecules. A translation of the molecule gives rise to exactly the same intensities, but as rotation in general changes the intensities totally. However even in the case of rotation a quantity called the angular correlations, while dependent on the structure, do not depend of the state of rotation or translation and is thus ideally placed to allow structure determination of molecules typically injected into an XFEL in the form of particles of constant structure but unknown orientation or position. What is more, the absence of translational periodicity as in a crystal, allows the determination of the phases of the scattered amplitudes by an iterative phasing algorithm. We will discuss the use of angular correlations to determine the structures of proteins and viruses, with an XFEL and even raid time resolved changes in their structure

Kakoli Bose

Tata Memorial Centre, India

Title: Structural insights into mode of regulation of serine protease HtrA2

Biography:

Abstract:

High-temperature requirement protease A2 (HtrA2), a proapoptotic serine protease is involved in maintaining mitochondrial homeostasis. This multifaceted protein has been implicated in several diseases including cancer and neurodegeneration thus making it an important therapeutic target. HtrA2 comprises a short N-terminal region, a serine protease domain and regulatory PDZ (protein-protein interaction) domain. The complex trimeric structure, intricate PDZ-protease crosstalk, allosteric mechanism of activation that is mediated both through its N- as well as C-termini, and most importantly its involvement in both caspase-dependent as well as independent apoptotic mechanism has made this protease an important molecule for biomedical research. Unlike other members of the family, human HtrA2 has been found to be activated through its short N-terminal region in addition to the classical substrate/adapter binding pocket in the PDZ domain. Interaction with inhibitor of apoptosis proteins (such as XIAP) through its N-terminus, leads not only to subsequent cleavage of the molecule but also simultaneous activation of HtrA2, suggesting a â€˜positive feedbackâ€™ mechanism. Similar mechanism is observed for PDZ-mediated substrate binding and activation as well. Therefore, understanding this complex mechanism and identifying the dual regulatory switch of its allosteric activation will help devise modulators with desired characteristics for therapeutic intervention against diseases it is associated with. It will also shed light on how point mutations lead to its inactivation as observed in diseases such as Alzheimerâ€™s and Parkinsonâ€™s. Keeping these in mind, here we aim at understanding the structural correlates of mode of activation of HtrA2 and several pathogenic mutants (in complex with substrates) at atomic level using X-ray crystallography and biophysical probes.

Track 5: Crystallography in Materials Science

Location: Houston

Chair

Andriy Lotnyk

Leibniz Institute of Surface Modification, Germany

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-UniversitÃ¤t MÃ¼nchen, Germany

Title: Synthesis of (doped) ABO2 nanoparticles: Can this work at temperatures â‰¤90Â°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:

Abstract:

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.

Track 3: Chemical Crystallography

Location: Houston

Chair

Jean Guillaume Eon

Universidade Federal do Rio de Janeiro, Brazil

Session Introduction

Jean-Guillaume Eon

Universidade Federal do Rio de Janeiro, Brazil

Title: Topological features in crystal structures: A quotient graph-assisted analysis of underlying nets and their embeddings

Time : 10:00 - 10:25

Biography:

Jean-Guillaume Eon completed his PhD from Université de Technologie de Compiègne (France) in 1984. He is the Director of a research group on Oxidation Catalysis at the Federal University of Rio de Janeiro, Brazil. He has published more than 60 papers in chemistry and crystallography journals and has been serving as an Editorial Board Member for Acta Crystallographica, Section A.

Abstract:

Yuichi Shimazaki

Ibaraki University, Japan

Title: X-ray crystal structures of the one-electron oxidized metalâ€“phenolate complexes; geometric and electronic structures relationship

Time : 10:25-10:50

Biography:

Yuichi Shimazaki received his Doctor’s degree in Science from Nagoya University in 2000 under the supervision of Professor Osamu Yamauchi. He joined Professor Yoshinori Naruta’s group at Kyushu University as Assistant Professor and worked on the redox behavior of various metal porphyrin complexes as models of the active site of metalloenzymes. In 2008, he was promoted to Associate Professor at the College of Science, Ibaraki University. His research interests include the oxidation chemistry of the complexes of various metal ions, model studies of metalloenzymes, bioorganometallic chemistry, and weak interactions in metal-organic molecule systems.

Abstract:

Oxidation chemistry of redox active transition metal complexes with pro-radical ligands and their detailed electronic structures have been actively pursued in recent years. An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin p-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Many efforts for determination of the experimental oxidation number have been close to the goal of the “truth oxidation state” in various oxidized metal complexes with redox-active ligands. Depending on the relative energies of the redox-active orbitals, metal complexes with non-innocent ligands exist in two limiting descriptions, either a metal-ligand radical (Mⁿ⁺(L^·)) or a high valent metal (M⁽ⁿ⁺¹⁾⁺(L^-)) complex. The reaction mechanisms of artificial and biological catalysts depend on the electronic structures of the high valent intermediates. However, structural characterizations of these species by X-ray diffraction methods have been rare due to their stability. Recently, some artificial metal−phenoxyl radical complexes as models of GO have been synthesized and successfully characterized by X-ray crystal structure. The one-electron oxidized metal-phenolate complexes showed various electronic structures depending on small perturbations, such as substitution of the phenolate ring and the chelate effect of the phenolate ligands and so on. In this presentation, I will focus on X-ray crystal structures of the one-electron oxidized metal–phenolate complexes in the case of metal complexes of diphenolate Schiff base ligands with 2N2O donor sets. Especially electronic and crystal structure relationship such as differences of metal-phenoxyl radical and high-valent metal phenolate complexes will be discussed.

Break: Networking and Refreshment Break 10:50-11:10 @ Foyer

Boniface P T Fokwa

University of California-Riverside, USA

Title: Magnetic ordering, frustration and possible spin liquid state from 1D Cr3-triangles in the TiCrIr2 xOsxB2 series

Time : 11:10-11:35

Biography:

Boniface P T Fokwa completed his PhD in 2003 from the Dresden University of Technology (Germany) and Post-doctoral studies from the RWTH Aachen University (Germany). He is an Associate Editor for Encyclopedia of Inorganic and Bioinorganic Chemistry (Wiley). He has published more than 70 papers in reputed journals and has won several awards including the prestigious Heisenberg Fellowship from the German Research Foundation and was Visiting Scientist at University of Auckland (New Zealand) and Cornell University as well as Visiting Professor at UCLA.

Abstract:

A new series of compounds TiCrIr_2â€‘xOs_xB₂ (x=0-2) was successfully synthesized and characterized using X-ray diffraction as well as energy-dispersive X-ray analysis. All members of the series crystallize in the hexagonal non-centrosymmetric Ti_1+xOs₂_-_xRuB₂ structure type (space group P2m, no. 189, Pearson symbol hP18). The structure contains trigonal planar B₄ units strongly interacting with triangles of magnetically active Cr atoms, which are stacked on each other to form isolated Cr₃-chains along the c-axis. Magnetization measurements of TiCrIr₂B₂(34 valence electrons, VE) reveal ferrimagnetic behavior below T_C=275 K with a large, negative Weiss constant of -750 K. Density functional theory calculations demonstrate magnetic frustration due to indirect antiferromagnetic interactions within the Cr₃ triangles competing with direct ferromagnetic interactions. Tuning the valence electron count by replacing Ir with Os changes the magnetic behavior in the series. Magnetization measurements of TiCrIrOsB₂ (33 VE) and TiCrOs₂B₂ (32 VE) exhibit paramagnetic behavior with features reminiscent of the spin liquid state. Interestingly, the crystal orbital Hamilton population (COHP) of TiCrIr₂B₂ indicates Cr-Cr antibonding interactions above 32.9 VE, but part of the Cr-Cr antibonding region is already occupied in TiCrOs₂B₂ even though it has 32 valence electrons. Therefore, the TiCrIr_2â€‘xOs_xB₂ (x=0-2) series do not follow rigid band approximation.

Takeru Ito

Tokai University, Japan

Title: Oxide cluster-surfactant hybrid single crystals toward solid electrolyte

Time : 11:35-12:00

Biography:

Takeru Ito has received his Doctor’s degree in 2001 at the University of Tokyo. After his Post-doctoral studies from the University of Tokyo and Tokyo Institute of Technology, he was appointed as an Assistant Professor at the Tokyo Institute of Technology. He moved to Tokai University in 2008, and now he is an Associate Professor. His research interests are focused on the synthesis and functionalization of Polyoxometalate Surfactant Hybrid Crystals.

Abstract:

To synthesize highly conductive materials is crucial for lithium-ion or fuel-cell battery technology due to their structural stability and easiness for handling. A promising strategy is to hybridize inorganic and organic molecular components and to construct crystalline layered structures beneficial to the emergence of conductive property. Polyoxometalate oxide cluster anions having characteristic redox properties are suitable as inorganic components. Polyoxometalates can be hybridized with cationic surfactants to form stable layered single crystals. Such ionic crystals are rare, and both polyoxometalate and surfactant components can be variously selected to build up functional inorganic-organic hybrid crystals. The polyoxometalate-surfactant hybrid crystals were synthesized by cation-exchange reaction with pH-adjusted solutions of molybdate, tungstate, and vanadate oxoanions. Single crystals were obtained from the filtrate solutions or by recrystallization of the crude precipitates, and subjected to X-ray structure analyses. Decatungstate and tetra-molybdate anions formed stable single crystals together with hexadecylpyridinium. The crystals exhibited the alternate stacking of polyoxometalate inorganic layers and surfactant organic layers. The obtained conductivity values were in the range of 10⁻⁶ to 10⁻⁵ S cm⁻¹ order over 423 K under anhydrous atmosphere. Decavanadate anion formed layered crystals with alkyltrimethylammonium. The hybrid crystals which comprise diprotonated decavanadate species exhibited anhydrous proton conductivity at intermediate temperatures (>373 K), which is possible for proton-conducting electrolyte of fuel cells.

Marietjie Schutte-Smith

University of the Free State, South Africa

Title: The investigation of chemical crystallography and kinetic reactivity of Re(I) tricarbonyl complexes

Time : 12:00-12:25

Biography:

Marietjie Schutte-Smith has completed her PhD at the University of the Free State, Bloemfontein, South Africa. She was appointed as a Lecturer immediately after the completion of her PhD from 2012 and were promoted to Senior Lecturer in 2016. She is supervising two MSc and six PhD students and she has published 21 articles.

Abstract:

The coordination chemistry of rhenium and technetium has gained major interest for the possible use in radiopharmacy, due to several favorable properties. A number of fac-[M(CO)₃]⁺ (M=Re, ^99mTc) type complexes have been synthesized to date with a large number of ligand systems. The three labile aqua ligands on the starting synthon fac-[Re(CO)₃(H₂O)₃]⁺ can easily be substituted by a variety and/or combinations of ligands producing stable compounds and potential radiopharmaceuticals with many different characteristics. We focus on the fac-[Re(CO)₃]⁺moiety and related compounds by adopting the [2+1] approach. The solid state behaviour and the effects like the charge, the donor atoms and electron donating and withdrawing effects of the ligands coordinated to the metal are explored. The influence of the coordinated bidentate ligands on the rate of substitution by a variety of entering ligands in solution is also investigated. The aqueous kinetics of fac-Re(I) tricarbonyl complexes are virtually unexplored. We synthesized a water soluble complex which allowed us to evaluate the reactivity of a fac-Re(I) tricarbonyl type complexes in aqueous medium which is imperative for biomedical application. The first high pressure substitution kinetics on a fac-[Re(L,L’-bid)(CO)₃(CH₃OH)] complex are also reported here.

Werner Paschinger

University of Vienna, Austria

Title: Relations between crystal structures and physical properties in the ternary systems CexTySnz (T = Pd or Pt)

Time : 12:25-12:50

Biography:

Werner Paschinger stared his studies in chemistry and physics at the University of Vienna in 2005. In 2013 he received his Bachelor of Science (B.Sc.) and in 2014 his Master of Science (M.Sc.) both from chemistry working on intermetallic compounds and thermoelectric materials within the group of Prof. Rogl at the Department of Physical Chemistry. Since April 2014 he is doing his PhD within the MATFLEXEND project at the Institute of Materials Chemistry & Research under supervision of Prof. Bismarck.

Abstract:

Although hitherto still no phase diagrams exist for the ternary systems Ce_xT_ySn_z (T = Pd or Pt), several compounds of these systems are in the focus of interest due to a number of interesting physical properties. Up to now, they have mainly been characterized by their magnetic properties, but more recently attracted attention due to their possible application as thermoelectric materials. For example, the hybridization of the 4f state of the Ce atom with conduction electrons of T and Sn atoms in Ce₃Pt₃Bi₄ and CeRu₄Sn₆ or Ce₄Pt₁₂Sn₂₅ with complex structures gives rise to a large thermopower, which is one of the prerequisites for thermoelectric application. For a proper interpretation and understanding of physical properties, the knowledge of the compounds’ crystal structure is of high importance. Therefore the relation of physical properties to structural motives in both systems will be discussed and compared to each other. Furthermore, we will introduce the crystal structure of two novel ternary compounds, CePd₃Sn₂ and Ce₃Pt₄Sn₆, derived by direct methods from X-ray single crystal data. Whereas CePd₃Sn₂ crystallizes in an orthorhombic structure, Ce₃Pt₄Sn₆ seems to coexist in a monoclinic and orthorhombic modification. For the monoclinic structure an intrinsically defect growth pattern was found backed by high resolution TEM. Structural units intrinsic to the title systems will be compared as well as to other related defect structures.

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Day :

Location: Houston

Chair

Gerd Kaupp

Session Introduction

Title: Breathing crystals-P, T-induced dynamics of heterospin crystals

Biography:

Abstract:

Title: Structure-based mechanistic insights into PAM-dependent spacer acquisition for incorporation into the CRISPR array

Biography:

Abstract:

Title: Two alternative structures of oxygen-evolving complex in photosystem II found by X-ray crystallography at extremely low doses

Biography:

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Title: Structure determination from powder diffraction data of self-assembled structures consisting of beta-peptide foldamers

Biography:

Abstract:

Title: Structural insights into mode of regulation of serine protease HtrA2

Biography:

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Title: Hydrated nickel(II) ions: The new secondary building units for the formation of 2D and 3D cationic water networks

Biography:

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Title: Structure determination by correlated scattering

Biography:

Abstract:

Title: Structural insights into the activation process of the opioid mu receptor

Biography:

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Title: Numerical simulation of liquid phase diffusion growth of SiGe single crystals using fixed and dynamic grid techniques: A comparison

Biography:

Abstract:

Title: Algorithms for generating coincidence site lattices (CSLs) and near-CSLs in arbitrary bravais lattice systems

Biography:

Abstract:

Title: NMR Crystallography: When nuclear magnetic resonance and diffraction meet

Biography:

Abstract:

Title: What makes cellulose auxetic?

Biography:

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Title: Synthesis of gadolinium oxynitride layer on Si by nitrogen ion implantation

Biography:

Abstract:

Title: Local atomic arrangement in Ge-Sb-Te phase-change thin films

Biography:

Abstract:

Title: Synthesis of (doped) ABO2 nanoparticles: Can this work at temperatures â‰¤ 90 Â°C without using an additional reducing agent?

Biography:

Abstract:

Title: Crystal structure, thermal, phase transition of organic â€“ inorganic hybrids of the formula NH3(CH2)nNH3CoX4, n = 3 - 9, X = Cl, Br

Biography:

Abstract:

Title: Scanning very low energy electron microscopy as a tool for obtaining crystallography-related information from single crystal and polycrystalline metals

Biography:

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Title: Importance of crystallography in material science

Biography:

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Title: Identification of Singular interfaces with ï€ ï„g vectors

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Title: Studies on synthesis and adsorption/Thermodynamics of metal organic frameworks

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Title: Synthesis and applications of porous materials for gas storage

Biography:

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Title: Transport property measurements on tungsten diselenide single crystals doped by copper

Biography:

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Title: Crystallographic and molecular packing interaction analysis of cholest-based steroids: A CSD study

Biography:

Abstract:

Title: Structural and optical studies on rare earth doped L-Histidine hydrochloride mono hydrate single crystals

Biography:

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Title: Structural and morphological characterization of tin oxide films prepared by the RGTO method

Title: Identification of Singular interfaces with ï€ ï„g vectors