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20 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I11-High Resolution Powder Diffraction	From formulation to structure: 3D electron diffraction for the structure solution of a new indomethacin polymorph from an amorphous solid dispersion Helen W. Leung , Royston C. B. Copley , Giulio I. Lampronti , Sarah J. Day , Lucy K. Saunders , Duncan N. Johnstone , Paul A. Midgley Iucrj 11, 744 - 748 DOI: 10.1107/S2052252524008121 Diamond Proposal Number(s): [34800] Open Access Show Abstract ▼ Abstract: 3D electron diffraction (3DED) is increasingly employed to determine molecular and crystal structures from micro-crystals. Indomethacin is a well known, marketed, small-molecule non-steroidal anti-inflammatory drug with eight known polymorphic forms, of which four structures have been elucidated to date. Using 3DED, we determined the structure of a new ninth polymorph, σ, found within an amorphous solid dispersion, a product formulation sometimes used for active pharmaceutical ingredients with poor aqueous solubility. Subsequently, we found that σ indomethacin can be produced from direct solvent evaporation using dichloromethane. These results demonstrate the relevance of 3DED within drug development to directly probe product formulations.	Sep 2024
I11-High Resolution Powder Diffraction I19-Small Molecule Single Crystal Diffraction	Exploring pyroelectricity, thermal and photochemical switching in a hybrid organic-inorganic crystal by in-situ X-ray diffraction Joshua J. Morris , Chris R. Bowen , Ben A. Coulson , Mark Eaton , Paul R. Raithby , Lucy K. Saunders , Jonathan M. Skelton , Qingping Wang , Mark R. Warren , Yan Zhang , Lauren Hatcher Angewandte Chemie International Edition DOI: 10.1002/anie.202401552 Diamond Proposal Number(s): [28436, 31624] Open Access Show Abstract ▼ Abstract: The switching behavior of the novel hybrid material (FA)Na[Fe(CN)5(NO)].H2O (1) in response to temperature (T), light irradiation and electric field (E) is studied using in-situ X-ray diffraction (XRD). Crystals of 1 display piezoelectricity, pyroelectricity, second and third harmonic generation. XRD shows that the FA+ are disordered at room-temperature, but stepwise cooling from 273-100K induces gradual ordering, while cooling under an applied field (E = +40kVcm-1) induces a sudden phase change at 140K. Structural-dynamics calculations suggest the field pushes the system into a region of the structural potential-energy surface that is otherwise inaccessible, demonstrating that application of T and E offers an effective route to manipulating the crystal chemistry of these materials. Photocrystallography also reveals photoinduced linkage isomerism, which coexists with but is not correlated to other switching behaviors. These experiments highlight a new approach to in-situ studies of hybrid materials, providing insight into the structure-property relationships that underpin their functionality.	Mar 2024
I15-1-X-ray Pair Distribution Function (XPDF)	Noncovalent bonding assessment by Pair Distribution Function Lucy K. Saunders , Daniel J. M. Irving , Philip A. Chater , Maria Diaz-Lopez Faraday Discussions DOI: 10.1039/D2FD00159D Open Access Show Abstract ▼ Abstract: Noncovalent interactions are essential in the formation and properties of a diverse range of materials. However, reliably identifying the noncovalent interactions remains challenging using conventional methods such as X-ray diffraction, especially in nanocrystalline, poorly crystalline or amorphous materials which lack long-range lattice periodicity. Here, we demonstrate the accurate determinations of deviations in the local structure and tilting of aromatic rings during the temperature-induced first order structural transition in the 1:1 adduct of 4,4’-bipyridinium squarate from low temperature form HAZFAP01 to high temperature HAZFAP07. This work demonstrates how Pair Distribution Function (PDF) analyses can improve our understanding of local structural deviations resulting from noncovalent bonds and guide the development of novel functional materials.	Jan 2023
	Uncovering the role of non-covalent interactions in solid-state photoswitches by non-spherical structure refinements with NoSpherA2 Lauren E. Hatcher , Lucy K. Saunders , Ben A. Coulson Faraday Discussions DOI: 10.1039/D2FD00158F Open Access Show Abstract ▼ Abstract: We present a charge density study of two linkage isomer photoswitches, [Pd(Bu4dien)(NO2)]BPh4.THF (1) and [Ni(Et4dien)(NO2)2] (2) using Hirshfeld Atom Refinement (HAR) methods implemented via the NoSpherA2 interface in Olex2. HAR is used to explore the electron density distribution in the photoswitchable molecules of 1 and 2, to gain an in-depth understanding of key bonding features and their influence on the single-crystal-to-single-crystal reaction. HAR analysis is also combined with ab initio calculations to explore the non-covalent interactions that influence physical properties of the photoswitches, such as the stability of the excited state nitrito-(η1-ONO) isomer. This insight can be fed back into the crystal engineering process to develop new and improved photoswitches that can be optimised towards specific applications.	Dec 2022
I19-Small Molecule Single Crystal Diffraction	LED-pump-X-ray-multiprobe crystallography for sub-second timescales Lauren E. Hatcher , Mark R. Warren , Jonathan M. Skelton , Anuradha R. Pallipurath , Lucy K. Saunders , David R. Allan , Paul Hathaway , Giulio Crevatin , David Omar , Ben. H. Williams , Ben A. Coulson , Chick C. Wilson , Paul R. Raithby Communications Chemistry 5 DOI: 10.1038/s42004-022-00716-1 Diamond Proposal Number(s): [17306, 19670] Open Access Show Abstract ▼ Abstract: The visualization of chemical processes that occur in the solid-state is key to the design of new functional materials. One of the challenges in these studies is to monitor the processes across a range of timescales in real-time. Here, we present a pump-multiprobe single-crystal X-ray diffraction (SCXRD) technique for studying photoexcited solid-state species with millisecond-to-minute lifetimes. We excite using pulsed LEDs and synchronise to a gated X-ray detector to collect 3D structures with sub-second time resolution while maximising photo-conversion and minimising beam damage. Our implementation provides complete control of the pump-multiprobe sequencing and can access a range of timescales using the same setup. Using LEDs allows variation of the intensity and pulse width and ensures uniform illumination of the crystal, spreading the energy load in time and space. We demonstrate our method by studying the variable-temperature kinetics of photo-activated linkage isomerism in [Pd(Bu4dien)(NO2)][BPh4] single-crystals. We further show that our method extends to following indicative Bragg reflections with a continuous readout Timepix3 detector chip. Our approach is applicable to a range of physical and biological processes that occur on millisecond and slower timescales, which cannot be studied using existing techniques.	Aug 2022
I19-Small Molecule Single Crystal Diffraction	Materials discovery and design limits in MDABCO perovskites Samuel D. Gale , Harry J. Lloyd , Louise Male , Mark R. Warren , Lucy K. Saunders , Paul A. Anderson , Hamish H.-M. Yeung Crystengcomm 91 DOI: 10.1039/D2CE00848C Diamond Proposal Number(s): [26118] Open Access Show Abstract ▼ Abstract: We report the structures of three new materials in the MDABCO-based perovskite family. Analysis of the Goldschmidt tolerance factor and octahedral factor enable us to propose compositional limits for pseudo-cubic perovskite phase formation and suggest directions for further materials discovery in this family of new ferroelectrics.	Aug 2022
B07-B1-Versatile Soft X-ray beamline: High Throughput ES1	Determination of H-atom positions in organic crystal structures by NEXAFS combined with density functional theory: a study of two-component systems containing isonicotinamide Paul T. Edwards , Lucy K. Saunders , David C. Grinter , Pilar Ferrer , Georg Held , Elizabeth J. Shotton , Sven L. M. Schroeder The Journal Of Physical Chemistry A DOI: 10.1021/acs.jpca.2c00439 Diamond Proposal Number(s): [29334] Open Access Show Abstract ▼ Abstract: It is important to be able to identify the precise position of H-atoms in hydrogen bonding interactions to fully understand the effects on the structure and properties of organic crystals. Using a combination of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory (DFT) quantum chemistry calculations, we demonstrate the sensitivity of core-level X-ray spectroscopy to the precise H-atom position within a donor-proton-acceptor system. Exploiting this sensitivity, we then combine the predictive power of DFT with the experimental NEXAFS, confirming the H-atom position identified using single-crystal X-ray diffraction (XRD) techniques more easily than using other H-atom sensitive techniques, such as neutron diffraction. This proof of principle experiment confirms the H-atom positions in structures obtained from XRD, providing evidence for the potential use of NEXAFS as a more accurate and easier method of locating H-atoms within organic crystals.	May 2022
I19-Small Molecule Single Crystal Diffraction	An electric field cell for performing in situ single-crystal synchrotron X-ray diffraction Lucy K. Saunders , Hamish H.-M. Yeung , Mark Warren , Peter Smith , Stuart Gurney , Stephen F. Dodsworth , Inigo Vitorica-Yrezabal , Adrian Wilcox , Paul V. Hathaway , Geoff Preece , Paul Roberts , Sarah A. Barnett , David R. Allan Journal Of Applied Crystallography 54 DOI: 10.1107/S1600576721007469 Diamond Proposal Number(s): [19670, 22964] Open Access Show Abstract ▼ Abstract: With the recent increase in research into ferroelectric, anti-ferroelectric and piezoelectric materials, studying the solid-state properties in situ under applied electric fields is vital in understanding the underlying processes. Where this behaviour is the result of atomic displacements, crystallographic insight has an important role. This work presents a sample environment designed to apply an electric field to single-crystal samples in situ on the small-molecule single-crystal diffraction beamline I19, Diamond Light Source (UK). The configuration and operation of the cell is described as well as its application to studies of a proton-transfer colour-change material.	Oct 2021
	Proton transfer on the edge of the salt/cocrystal continuum: X-ray photoelectron spectroscopy of three isonicotinamide salts Paul T. Edwards , Lucy K. Saunders , Anuradha R. Pallipurath , Andrew J. Britton , Elizabeth A. Willneff , Elizabeth J. Shotton , Sven L. M. Schroeder Crystal Growth & Design DOI: 10.1021/acs.cgd.1c00807 Show Abstract ▼ Abstract: X-ray photoelectron spectroscopy (XPS) has emerged as a technique that allows for characterization and classification of hydrogen bonding and proton transfer interactions in organic crystal structures, in a way that is complementary to crystallography by X-ray or neutron diffraction. Here, we analyze the nitrogen 1s core-level binding energies (BEs) of isonicotinamide (IN) systems with proton transfer between donor and acceptor groups at short distances. We show how a careful calibration of the BE scale places these salt systems correctly on the edge of the so-called salt–cocrystal continuum. We show how performing a fitting analysis of the data that is consistent with elemental analysis, expected stoichiometry, and quantification of adventitious carbon contamination facilitates the determination of absolute BEs with accuracy and reproducibility within ±0.1 eV. The determined N 1s core-level BEs of the protonated IN acceptors suggest that the local geometric arrangements of the donor, acceptor, and proton can influence the N 1s core-level BE significantly.	Sep 2021
I19-Small Molecule Single Crystal Diffraction	A quantum crystallographic approach to short hydrogen bonds Lucy Saunders , Anuradha R. Pallipurath , Matthias J. Gutmann , Harriott Nowell , Ningjin Zhang , David R. Allan Crystengcomm 10 DOI: 10.1039/D1CE00355K Diamond Proposal Number(s): [18193] Open Access Show Abstract ▼ Abstract: In this work we use high-resolution synchrotron X-ray diffraction for electron density mapping, in conjunction with ab initio modelling, to study short O—H⋯O and O+—H⋯O− hydrogen bonds whose behaviour is known to be tuneable by temperature. The short hydrogen bonds have donor–acceptor distances in the region of 2.45 Å and are formed in substituted urea and organic acid molecular complexes of N,N′-dimethylurea oxalic acid 2[thin space (1/6-em)]:[thin space (1/6-em)]1 (1), N,N-dimethylurea 2,4-dinitrobenzoate 1[thin space (1/6-em)]:[thin space (1/6-em)]1 (2) and N,N-dimethylurea 3,5-dinitrobenzoic acid 2[thin space (1/6-em)]:[thin space (1/6-em)]2 (3). From the combined analyses, these complexes are found to fall within the salt-cocrystal continuum and exhibit short hydrogen bonds that can be characterised as both strong and electrostatic (1, 3) or very strong with a significant covalent contribution (2). An additional charge assisted component is found to be important in distinguishing the relatively uncommon O—H⋯O pseudo-covalent interaction from a typical strong hydrogen bond. The electron density is found to be sensitive to the extent of static proton transfer, presenting it as a useful parameter in the study of the salt–cocrystal continuum. From complementary calculated hydrogen atom potentials, we attribute changes in proton position to the molecular environment. Calculated potentials also show zero barrier to proton migration, forming an ‘energy slide’ between the donor and acceptor atoms. The better fundamental understanding of the short hydrogen bond in the ‘zone of fluctuation’ presented in a salt-cocrystal continuum, enabled by studies like this, provide greater insight into their related properties and can have implications in the regulation of pharmaceutical materials.	Aug 2021

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