Dr Catherine Dejoie: High-resolution X-ray powder diffraction – Application to the study of CO2 trapping in microporous materials
Following the ESRF upgrade and the reconstruction of the storage ring in 2019, the increased brilliance allows new experiments to be carried out, with improved precision and pushing further the detection limits of subtle structural changes occurring in the materials. High-angular resolution powder diffraction, with well-defined and resolved diffraction peaks, is used generally to obtain high-quality data for complex structure refinements. The ID22 beamline of the ESRF is equipped with a Dectris Eiger2 X 2M-W CdTe pixel detector receiving the X-rays transmitted by the thirteen crystals of a custom-made multi-analyser stage [1]. A great advantage of this arrangement is the axial resolution provided by the 2D detector, which allows the effect of axial divergence, which causes the low-angle asymmetry in the peak shape of powder diffraction patterns, to be removed. A second advantage is that the axial acceptance of the detector can be increased as 2𝜃 increases, up to the 38 mm width of the detector, thus increasing the statistical quality of the high angle data while also improving the angular resolution. ID22 has implemented this approach systematically, as an automatic procedure, into its collection of high-resolution powder diffraction data. A case study developed inhouse in relation to the trapping of CO2 in microporous materials will be presented [2], benefitting from the overall improvement of the high-resolution data quality.
[1] Fitch A. et al., J. Synchrotron Rad. 30, 1003-1012 (2023).
[2] Lill J. et al., J. Phys. Chem. 126, 2214-2225 (2022).
Dr Martina Vrankić: A key purpose of high-pressure research – effect of pressure on structures and functionalities of materials
This talk was not recorded
The properties of inorganic and hybrid organic-inorganic materials under high pressure can be of practical importance in the manufacture and durability of devices. In particular, the powder X-ray diffraction and structural evolution under pressures from synchrotron radiation experiments, in a separate manner are raised for the selected inorganic and hybrid inorganic- organic materials to emphasize the need for this characterization method, without which it would be impossible to correlate structural and delicate physical and photophysical behavior. The inorganic materials with high bulk moduli (above 100 GPa) contrast with the more soft hybrid organic-inorganic materials, which usually, have bulk moduli between 10 and 20 GPa. The physical and chemical features of tuned, shape-selected ZnO particles are discussed in terms of response to external hydrostatic pressure using the synchrotron powder X-ray diffraction measurements and X-ray photoelectron spectroscopy fingerprints, latter giving an insight into the morphological versatility and surface diversity of ZnO powder. This talk will comparatively show that the diversity of size and shape of ZnO particles distinguishes the wurtzite-to-rocksalt transformation reversibility phenomena by dictating the microstructure-dependent deformation behavior and ultimately leads to different microstrain responses to hydrostatic pressure. In addition, an application of pressure to hybrid materials that are relatively soft can induce reversible, irreversible, insulator-to-metal, crystalline-to-amorphous, and piezochromic transitions that can lead to metallization and narrowing of the band gap. Exploring materials with useful properties that can be preserved under ambient conditions for application is one of the main goals of high-pressure research.
Dr Clive L. Oliver: Small molecular and crystal structure changes in MOFs leading to large differences in sorption and thermosalient properties
Metal-organic frameworks (MOFs) have attracted widespread attention for their porosity and applications in separation chemistry, catalysis, molecular sensing and gas storage. Mixed-ligand MOFs contain more than one type of ligand and offer the possibility of increased tailoring of structural features, such as chemical functionality or pore dimensions along particular directions. This talk will present a number of new MOFs constructed in our laboratory from commonly available ligands, which are often mixed-ligand MOFs, interpenetrated and show dynamic structural properties. Some of these MOFs are closely related in structure, in that they are isoreticular, yet show large differences in their thermal and sorption properties. In addition, an unexpected property of mechanical motion upon heating is revealed for one of the isoreticular MOF systems, a rare phenomenon for coordination polymers
The fact that crystals and crystallography are inherently beautiful should make communicating about them easy. However, good communication relies on more than just shouting into the void about how cool crystals are. If we want to have genuine and meaningful conversations about crystallography, we need to create activities and events that people want to engage with. This talk will critically explore a variety of crystallography science communication approaches, including citizen science, theatre, escape rooms, comedy, and board games. Through this lens, some suggested principles will be constructed for consideration for future crystallography engagement. We think crystallography is great, so let’s make sure the world does too!
Prof. Simona Galli: Navigating within the pores of advanced porous materials: The power of powder diffraction
The functional properties that a crystalline solid possesses depend not only on its chemical nature, but also on its crystal and molecular structure. By means of recent cases of study selected within the realm of metal-organic frameworks and covalent organic frameworks, the talk will demonstrate that (in situ) powder diffraction, exploited in the lab or at large scale facilities, is a powerful tool to unveil key structure-property relationships, thus enabling to rationalize the bulk properties under investigation with a molecular-level insight.
Prof. Henrik Rønnow & Dr Jian-Rui Soh: Fundamentals of neutron scattering
The fundamental interaction between the neutron dipolar field and the magnetisation density surrounding the scattering ion, lies at the heart of magnetic neutron diffraction. However, if the ion resides in an environment which breaks both time and spatial inversion symmetry, the current formalism for magnetic diffraction does not fully account for all the possible scattering mechanisms arising from the asymmetry of the magnetisation density cloud of the scatterer. In our work, we have (i) extended the theory of magnetic neutron diffraction to include these effects, (ii) developed a framework to calculate the associated neutron cross sections using density functional theory and (iii) employed spherical neutron polarimetry to provide direct experimental evidence for these multipoles in CuO.
Prof. Piero Macchi: Quantum crystallographic investigations of metal-metal bonded systems
In this lecture an overview is presented of the quantum chemical, crystallographic and quantum crystallographic studies on molecular systems containing bonds between transition metals.The X-ray diffraction experiments have been fundamental for establishing the occurrence of molecules featuring one or more bonds between metals.
However, because the chemistry of transition metals breaks Lewis rules, which are normally valid for organic molecules, for a correct interpretation of the nature of this chemical bond and the implication for the stability of metal clusters was necessary. The early charge density studies were only in part able to provide answers, but it was only thanks to the combination of advanced quantum chemical methods that scientists could unveil the nature of these bonds in more details. Quantum crystallography offers a seamlessly powerful way to complete the analysis, although much information is still hidden, and it requires even more complicated investigations.
The metal-metal bond is extremely elusive because it cannot be easily classified into a unique category. Instead, it encompasses almost continuously all the steps from strong covalent to non-covalent.
Dr Regine Herbst-Irmer: Twinning in Chemical Crystallography
A non-negligible percentage of crystal structures in chemical crystallography is derived from twinned crystals. The treatment of these data is dependent on the type of twinning. Twins by strict, pseudo or reticular merohedry may hamper space group determination and structure solution, while non-merohedral twins mainly hinder the data integration process. These different types will be explained in detail and examples for all types will be presented.
Dr Thomas A. White: Real-time crystallographic data processing with streaming data
Serial crystallography is already an infamous producer of large data volumes. Storing all of this data is already unsustainable, and the data rates will increase further as X-ray detectors and pulse rates get faster. A possible solution is to process the frames in real-time, as soon as they are read out from the detector, without ever hitting a filesystem. In this talk, I will describe how we deployed such a system for the P11 beamline at PETRA III, and discuss the implications on the way we carry out our experiments.
Dr Gift Mehlana: Metal-organic frameworks as platforms for hosting molecular and bio-catalysts for carbon dioxide hydrogenation
Organometallic compounds such as pincer complexes have been known to be highly active towards carbon dioxide hydrogenation. On the other hand, crystal engineering provide the design strategies for anchoring molecular complexes in metal-organic frameworks (MOFs). Combining these two areas would offer new materials which are highly active towards the conversion of carbon dioxide to high value chemicals. In our approach we have utilized diamine, diimine and pincer based complexes to build new MOFs with catalytic activity. Our research also explores new methods for introducing catalytically active sites in MOF pores. The successful synthesis of molecular catalysts inside MOF pores is confirmed by both spectroscopic and diffraction techniques. Results obtained from this work demonstrates that the introduction of molecular catalysts inside the MOF pores enhances the catalytic activity for the conversion of carbon dioxide to formic acid.Within this talk, Dr. Mehlana will also highlight the role played by AfCA in promoting science on the African Continent.
Prof. Alain Gibaud: Probing nano-sized objects by (grazing-incidence) small angle scattering and coherent X-ray diffraction imaging
Small angle scattering is a technique that is used to look at the morphology and the electron density of not necessarily long-range ordered nm to μm sized objects in contrast to wide angle scattering techniques which are usually applied to crystallized materials organized at the ångström scale. Since the founding studies of Guinier, Debye, Kratky and Porod in the 30s and 40s of the last century, small angle scattering techniques have been applied to a many different systems ranging from biomolecules to surfactants, polymers, and alloys.
Prof. Dr Holger Stark: Atomic-resolution structure determination of proteins by cryo-EM: Where are the limits?
This talk was not recorded
The technological advances in electron microscopy, in detector development and in available image processing tools made cryo-EM a highly successful and rapidly developing method for protein structure determination. The number of structures determined by cryo-EM is currently still growing exponentially and the resolution limit of the technique has constantly been improved over the last decade. We have determined the first true-atomic resolution structure of apoferritin by cryo-EM in which individual atoms are clearly resolved. However, at very high resolution, quality issues in cryo-EM density maps also become apparent. Microscope instrumentation plays a key role with respect to map resolution and map quality. Therefore, I will discuss the resolution limiting factors in cryo-EM and how these limitations can potentially be overcome in the future.
Prof. Chiara Massera: Turning “weakness” into strength: supramolecular interactions in crystals
Weak interactions have acquired importance in the scientific community over the last two decades. They have proved to be an essential feature in determining the chemical and physical properties of materials, influencing their three-dimensional structure, reactivity, organization, and biological activity. The number of papers and reviews dedicated to the crystallographic and theoretical study and analysis of hydrogen and halogen bonds, π···π and C—H···π interactions, just to cite a few, has grown exponentially over the years, underlining the applicability and usefulness of weak interactions to a wide range of scientific disciplines. Indeed, weak interactions are essential in the formation of inclusion compounds, in the self-assembly of host–guest molecular complexes, in molecular recognition, in the study of polymorphism, co-crystals, phase transitions and charge density. The mastering of supramolecular interactions can help to rationally design materials endowed with specific properties and it is an essential tool in crystal engineering. This talk will highlight the importance of structural analysis in understanding weak interactions in the solid state with examples taken from the literature and from personal research. This abstract has been adapted from: Acta Cryst. (2018). E74, 569.
Dr Nicole Benedek: Understanding the influence of crystal structure on the functional properties of complex oxides: Physical mechanisms and crystal chemistry
Recent experiments have demonstrated the potential for ultrafast changes in the functional properties of materials upon selective optical excitation of particular vibrational (phonon) modes. The chemical diversity of complex oxides, and their strong crystal structure-properties coupling, have made them ideal test systems for new experimental approaches that exploit anharmonic phonon couplings to induce and modify magnetism, superconductivity and ferroelectricity with light. In this talk, I will describe our recent theoretical efforts exploring ultrafast optical control of the functional properties of ABO3 perovskite oxides. In particular, I will focus on our attempts to connect the physical mechanisms of optical excitation to crystal chemistry using two examples: dynamical stabilization of a non-equilibrium magnetic phase in GdTiO3, and understanding changes in non-equilibrium structure and properties in terms of intrinsic microscopic quantities for LaAlO3 under pressure. Our work complements recent experimental studies involving X-ray free electron lasers to resolve subtle changes in crystal structure due to optical phonon pumping, and highlights the importance of understanding the contributions of small structural distortions to the optical response in perovskites, in contrast with large-amplitude distortions, such as so-called rotations of the BO6 octahedra.
Prof. Valeri Petkov: Structures with intrinsic disorder, limited dimensionality or under strong external stimuli studied by total X-ray scattering
We will introduce total X-ray scattering analysis briefly and show examples of its application on systems of current technological and scientific interest, including macromolecules, semiconductor alloys, layered oxides for battery applications, metallic nanoparticles grown in solution, catalysts at the cathode of operating fuel cells, ferroelectric perovskites, charge density waves in transition metal dichalcogenides and rare earth alloys in magnetic field.
Prof. Luca Bindi: From Penrose Tilings to the trinity test: The extraordinary story of the discovery of quasicrystals in nature
Quasicrystals are exotic forms of matter with symmetries that were once thought to be mathematically impossible. The first known examples were synthesized in the laboratory over 35 years ago, but could Nature have beaten us to the punch? This talk will describe the decades-long search to answer this question, resulting in one of the strangest scientific stories you are ever likely to hear.
Dr Kamil F. Dziubek: Adventures in Pressure-Temperature Space
According to the Oxford English Dictionary a phase diagram is “a diagram which represents the limits of stability of the various phases of a chemical system at equilibrium, with respect to two or more variables.” In high-pressure research these variables are most commonly referred to as temperature and pressure, for a given chemical composition. This definition, however, does not apply to the majority of simple molecular compounds consisting of light elements, including almost all organic compounds. These systems are metastable at any given thermodynamic conditions, as they never correspond to the Gibbs free energy minimum. In spite of that, metastable states are often promising technological materials. Moreover, dynamic compression experiments have recently demonstrated how the experimentally observed phase boundaries depend on transition kinetics. Hence, navigating the energetic landscape of highly polymorphic systems can lead to ‘dynamic phase diagrams’ or ‘metastable phase diagrams’ (transitional diagrams), which do not conform to the quoted definition, but can be extremely interesting for technological applications or fundamental studies. Throughout the talk, concepts will be illustrated by use cases from literature and own research.
Dr Hosea Nelson: Applications of electron diffraction in organic chemistry
In this talk I will discuss our groups efforts to use electron diffraction to solve problems in organic chemistry. We will specifically discuss applications in natural products science, including the structural re-assignment of well-known natural products and the discovery of new natural products. We will also discuss applications in the structural determination of organometallic complexes, reactive intermediates, and functional materials. A brief survey of opportunities for future discoveries and advances will also be discussed.
Katharina Edkins: Drugs and water – an unstructured approach to crystal forms
Hydrated crystal structures, i.e. crystal forms containing water as an integral part of the crystal lattice, are inherently difficult materials to work with in the pharmaceutical sciences. We thus need to know about the existence of hydrates as soon as possible in the development of a new drug to address solubility and stability issues during the formulation stage. To gain this information, current state-of-the-art is the serendipity-driven crystallisation screening, in some cases with the help of crystal structure prediction. In this talk, Katharina will present an alternative approach to thinking about hydrates, how and when they crystallise, and which technologies that are available to fundamentally understand the interaction between drugs and water.Kathi Edkins is Reader in Pharmaceutics at the University of Manchester where her research group focuses on pharmaceutical disordered materials ranging from glasses to gels with a special focus on the solution state before crystallisation. Being a pharmacist by training, Kathi studied the pharmaceutical solid state for her PhD in Innsbruck, Austria, before moving to Durham, UK, for a postdoc in crystallography. After a short stint as service crystallographer in Wuerzburg, Germany, Kathi’s academic career started as Lecturer at the newly formed Division of Pharmacy at Durham University in 2014 before moving to the School of Pharmacy at Queen’s University Belfast in 2017. She is in Manchester since 2020. She has a keen interest in using neutron scattering in the pharmaceutical field, and her research in this field was honoured by the BTM Willis Prize in 2016. She has published over 55 scientific research papers and held numerous invited talks at conferences and seminars. Currently, Kathi is serving as secretary to the SIG13 on Chemical Crystallography and Molecular Structure.
Simon Grabowsky – Quantum Crystallography – Developments and Applications
In this seminar we welcome Simon Grabowsky, currently Research Group Leader and Privatdozent at the Department of Chemistry, Biochemistry and Pharmaceutical Sciences at the University of Bern since August of 2019. Before he was Emmy Noether Research Group Leader then Extraordinary Professor, both at the University of Bremen. Furthermore, he was Australian Postdoctoral Fellow and Assistant Research Professor at the University of Western Australia.In his talk Simon will present his perspectives on and insights to his field and highlight cornerstones of his research.
The main field of the research group is method development in quantum crystallography and application of the new methods to bonding analysis in inorganic and bio-organic chemistry. They have a strong focus on a broad spectrum of areas: “X-ray Wavefunction Refinement”, “Relativistic Effects in the Electron Density” and they investigate “Electron-Density – Property Relationships in Inorganic Chemistry”
John R Helliwell – Precision and accuracy in structure–function studies
In this seminar we will look at the terms precision and accuracy and how they can be understood in crystallography. The talk will be held along the lines that are also drawn in John’s recent article: Combining X-rays, neutrons and electrons, and NMR, for precision and accuracy in structure–function studies
Biography: John R Helliwell, DSc (Physics, University of York), DPhil (Molecular Biophysics, Oxford University) is Emeritus Professor of Chemistry at The University of Manchester, where he served as Professor of Structural Chemistry from 1989 to 2012. Academic teaching from 1979 till 1988 was at the Universities of Keele and York in the physics departments there. He is a researcher in the fields of crystallography, biophysics, structural biology, structural chemistry and data science. He was also based at the Synchrotron Radiation Source at the UK’s Daresbury Laboratory, in various periods of appointment between 1979 to 2008, including in 2002 as Director of Synchrotron Radiation Science. He is a Fellow of the Institute of Physics, the Royal Society of Chemistry, the Royal Society of Biology, and the American Crystallographic Association, an Honorary Member of the British Crystallographic Association and of the British Biophysical Society. He is a Corresponding member of the Royal Academy of Sciences & Arts of Barcelona, Spain and Honorary Member of the National Institute of Chemistry, Slovenia. His awards include the European Crystallographic Association Eighth Max Perutz Prize 2015, the American Crystallographic Association Patterson Award 2014, and the ‘Professor K Banerjee Endowment Lecture Silver Medal’ of the Indian Association for the Cultivation of Science (IACS) 2001. He published over 200 scientific research papers and several books, e.g. Macromolecular Crystallography with Synchrotron Radiation with Cambridge University Press (1992), published in paperback in 2005 and Macromolecular Crystallization and Crystal Perfection with N E Chayen and E H Snell), Oxford University Press – International Union of Crystallography Monographs on Crystallography (2010). He has published several Scientific Life, popular science, books in recent years, which are with CRC Press Taylor and Francis.
Melanie Vollmar – My protein crystal and its data quality
Protein crystals are used in X-ray diffraction experiments to determine the 3D structure of the macromolecule which forms the building blocks of the crystal. During a diffraction experiments such a crystal is rotated in an X-ray beam and the diffracted waves create a distinct pattern which is recorded as intensities on a detector. The neatness of packing the building blocks inside the crystal, the stability and brightness of the X-ray source and beam along with the recording capabilities of the detector all have an influence on the quality of the data that can be achieved in a given experiment. The process for turning the intensity spots on a diffraction image into a list of reflections is called data reduction. Several metrics have been developed, to assess the quality of data at different steps during the data reduction process. The resulting list of reflections and the quality of the data encoded therein is crucial for the next step, phase determination, which allows a crystallographer to elucidate the internal 3D structure of the building blocks. For data of low quality, a researcher will often encounter many difficulties when attempting phase determination and most likely will not be able to identify the locations of atoms within the crystal.In this seminar we will look at the general term “data quality”, which factors affect the data, how this applies to the case of macromolecular crystallography, what procedures have been put in place to assess data quality and how to improve it.
Andrea Thorn – Understanding COVID-19 through Molecular Structures
Dr Andrea Thorn is a crystallographer and structural biologist based in Hamburg. She is a driving force behind the so-called Corona Structural Taskforce (https://insidecorona.net/). Andrea did her PhD from 2008-2011 in George Sheldrick’s lab at the University of Göttingen on the topic: “Practical approaches to macromolecular X-ray structure determination”. She then went for a postdoc to the UK, first with Prof. Dr Randy Read and then as a Marie Curie Fellow with Garib Murshudov. She did then software development at the Diamond Light Source synchrotron while working on Cryo-EM. After a one-year stay at the XFEL in Hamburg she became a junior group leader in Würzburg for 3 years. Since October 2020 she is a group leader at the University of Hamburg.Andrea is a computational crystallographer working on the development of models to handle structural analysis of proteins and macromolecules by Cryo-EM. In her presentation she will talk about her perspectives on the achievements of crystallographic research in the context of the COVID-19 pandemic.
