| 1. |
- Lightowler, Molly, et al.
(författare)
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Phase identification and discovery of an elusive polymorph of drug-polymer inclusion complex using automated 3D electron diffraction
- 2024
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Ingår i: Angewandte Chemie International Edition. - 1433-7851 .- 1521-3773. ; 63:16
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Tidskriftsartikel (refereegranskat)abstract
- 3D electron diffraction (3D ED) has shown great potential in crystal structure determination in materials, small organic molecules, and macromolecules. In this work, an automated, low-dose and low-bias 3D ED protocol has been implemented to identify six phases from a multiple-phase melt-crystallisation product of an active pharmaceutical ingredient, griseofulvin (GSF). Batch data collection under low-dose conditions using a widely available commercial software was combined with automated data analysis to collect and process over 230 datasets in three days. Accurate unit cell parameters obtained from 3D ED data allowed direct phase identification of GSF Forms III, I and the known GSF inclusion complex (IC) with polyethylene glycol (PEG) (GSF-PEG IC-I), as well as three minor phases, namely GSF Forms II, V and an elusive new phase, GSF-PEG IC-II. Their structures were then directly determined by 3D ED. Furthermore, we reveal how the stabilities of the two GSF-PEG IC polymorphs are closely related to their crystal structures. These results demonstrate the power of automated 3D ED for accurate phase identification and direct structure determination of complex, beam-sensitive crystallisation products, which is significant for drug development where solid form screening is crucial for the overall efficacy of the drug product.
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| 2. |
- Wang, Lei, et al.
(författare)
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Exploring Bronsted acids confined in the 10-ring channels of the zeolite ferrierite
- 2018
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033 .- 1466-8033. ; 20:6, s. 699-702
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Tidskriftsartikel (refereegranskat)abstract
- Locations of Bronsted acids confined in the 10-ring channels of ferrierite have been unravelled by refining structural models of as-made and probe-molecule-adsorbed samples against powder X-ray diffraction data, respectively. By analysing both refinement results, it is suggested that Bronsted acid sites can be tailored by controlling the distribution of inorganic ions.
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| 3. |
- Yuan, Shuai, et al.
(författare)
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[Ti8Zr2O12(COO)(16)] Cluster : An Ideal Inorganic Building Unit for Photoactive Metal-Organic Frameworks
- 2018
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Ingår i: Acs Central Science. - : American Chemical Society (ACS). - 2374-7943 .- 2374-7951. ; 4:1, s. 105-111
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Tidskriftsartikel (refereegranskat)abstract
- Metal-organic frameworks (MOFs) based on Ti-oxo clusters (Ti-MOFs) represent a naturally self-assembled superlattice of TiO2 nanoparticles separated by designable organic linkers as antenna chromophores, epitomizing a promising platform for solar energy conversion. However, despite the vast, diverse, and well-developed Ti-cluster chemistry, only a scarce number of Ti-MOFs have been documented. The synthetic conditions of most Ti-based clusters are incompatible with those required for MOF crystallization, which has severely limited the development of Ti-MOFs. This challenge has been met herein by the discovery of the [Ti8Zr2O12(COO)(16)] cluster as a nearly ideal building unit for photoactive MOFs. A family of isoreticular photoactive MOFs were assembled, and their orbital alignments were fine-tuned by rational functionalization of organic linkers under computational guidance. These MOFs demonstrate high porosity, excellent chemical stability, tunable photoresponse, and good activity toward photocatalytic hydrogen evolution reactions. The discovery of the [Ti8Zr2O12(COO)(16)] cluster and the facile construction of photoactive MOFs from this cluster shall pave the way for the development of future Ti-MOF-based photocatalysts. GRAPHICS
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| 4. |
- Bengtsson, Viktor E. G., 1989-
(författare)
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Crystal Structure Determination by 3D Electron Diffraction — New Software for Facilitating Data Processing
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Three-Dimensional Electron Diffraction (3DED) is a useful technique for determining crystal structures from very small crystals (hundreds of \si{\nano\meter} or less). Examples of such crystals are zeolites, metal-organic frameworks (MOFs), pharmaceuticals, and proteins. Knowledge of the structure is useful for understanding and potentially changing how the material or substance functions. This thesis includes the structure determination of the MOFs CAU-42 and CAU-45 as well as the development of the software \emph{Scipion-ED} in response to challenges during the processing of 3DED data from the two MOFs. Both MOFs displayed correlated disorder, where disorder in one part of the structure influences the configuration of disorder in nearby parts. The influence of the solvent during synthesis on the final structured is also discussed. The development and design of the software \emph{Scipion-ED} is described. It is a graphical user interface based on \emph{scipion-pyworkflow} for workflow-centric data processing. The described implementation includes the foundation for using \emph{Scipion} to process 3DED data, as well as a plugin for processing with \emph{DIALS}. Approaches are also described for extending the software to use \emph{XDS} or other programs.
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| 5. |
- Bengtsson, Viktor E. G., 1989-, et al.
(författare)
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Scipion-ED : a graphical user interface for batch processing and analysis of 3D ED/MicroED data
- 2022
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Ingår i: Journal of applied crystallography. - : International Union of Crystallography (IUCr). - 0021-8898 .- 1600-5767. ; 55:3, s. 638-646
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional electron diffraction (3D ED)/microcrystal electron diffraction (MicroED) techniques are gaining in popularity. However, the data processing often does not fit existing graphical user interface software, instead requiring the use of the terminal or scripting. Scipion-ED, described in this article, provides a graphical user interface and extendable framework for processing of 3D ED/MicroED data. An illustrative project is described, in which multiple 3D ED/MicroED data sets collected on tetragonal lysozyme were processed with DIALS through the Scipion-ED interface. The ability to resolve unmodelled features in the electrostatic potential map was compared between three strategies for merging data sets.
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| 6. |
- Bortolini, C., et al.
(författare)
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Atomic Structure of Amyloid Crystals
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A deep understanding of the self-assembly and crystallization of biomolecules as highly ordered biomaterials is crucial to enable the design and the generation of complex functional systems for cutting-edge applications in nanotechnology and biomedicine. In this work, we determined the atomic structure of Aβ16-20 crystals, a fragment of amyloid-β which aberrant folding is linked to the etiology of Alzheimer’s disease, the most common cause of dementia. We detailed the hierarchical aggregation mechanism of Aβ16-20 into highly ordered crystals and revealed that the self-assembly is reversible, leading to the formation of oligomers as an intermediate. Our structural investigation combined with molecular dynamics simulations highlights how a combination of favorable non-covalent interactions drives the efficient fast self-assembly and enhanced stability. We studied the chemical and surface properties of amyloid crystals, including their mechanical properties and their capability to transmit light; the long-rang order of Aβ16-20 crystals enables them to be used as optical waveguide materials for biologically based modulation and sensing. Our results shed new light on pathogenic amyloid assembly at the atomic level and reveal the potential of amyloid crystals for applications in nanotechnology.
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| 7. |
- Broadhurst, Edward T., et al.
(författare)
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Polymorph evolution during crystal growth studied by 3D electron diffraction
- 2020
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Ingår i: IUCrJ. - 2052-2525. ; 7, s. 5-9
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Tidskriftsartikel (refereegranskat)abstract
- 3D electron diffraction (3DED) has been used to follow polymorph evolution in the crystallization of glycine from aqueous solution. The three polymorphs of glycine which exist under ambient conditions follow the stability order beta < alpha < gamma. The least stable beta polymorph forms within the first 3 min, but this begins to yield the alpha-form after only 1 min more. Both structures could be determined from continuous rotation electron diffraction data collected in less than 20 s on crystals of thickness similar to 100 nm. Even though the gamma-form is thermodynamically the most stable polymorph, kinetics favour the alpha-form, which dominates after prolonged standing. In the same sample, some beta and one crystallite of the gamma polymorph were also observed.
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| 8. |
- Carmona, Francisco J., et al.
(författare)
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Coordination Modulation Method To Prepare New Metal-Organic Framework-Based CO-Releasing Materials
- 2018
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:37, s. 31158-31167
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Tidskriftsartikel (refereegranskat)abstract
- Aluminum-based metal organic frameworks (MOFs), [Al(OH)(SDC)](n), (H2SDC: 4,4'-stilbenedicarboxylic acid), also known as CYCU-3, were prepared by means of the coordination modulation method to produce materials with different crystal size and morphology. In particular, we screened several reagent concentrations (20-60 mM) and modulator/ligand ratios (0-50), leading to 20 CYCU x_y materials (x: reagent concentration, y = modulator/ligand ratio) with different particle size and morphology. Noteworthy, the use of high modulator/ligand ratio gives rise to a new phase of CYCU-3 (CYCU-3' x_50 series), which was structurally analyzed. Afterward, to test the potential of these materials as CO-prodrug carriers, we selected three of them to adsorb the photo- and bioactive CO-releasing molecule (CORM) ALF794 [Mo(CNCMe2CO2H)(3)(CO)(3)] (CNCMe2CO2H = 2-isocyano-2-methyl propionic acid): (i) CYCU-3 20_0, particles in the nanometric range; (ii) CYCU-3 50_5, bar-type particles with heterogeneous size, and (iii) CYCU-3' 50_50, a new phase analogous to pristine CYCU-3. The corresponding hybrid materials were fully characterized, revealing that CYCU-3 20_0 with the smallest particle size was not stable under the drug loading conditions. Regarding the other two materials, similar ALF794 loadings were found (0.20 and 0.19 CORM/MOF molar ratios for ALF794@CYCU-3 50_5 and ALF794@CYCU-3' 50_50, respectively). In addition, these hybrid systems behave as CO-releasing materials (CORMAs), retaining the photoactive properties of the pristine CORM in both phosphate saline solution and solid state. Finally, the metal leaching studies in solution confirmed that ALF794@CYCU-3' 50_50 shows a good retention capacity toward the potentially toxic molybdenum fragments (7S% of retention after 72 h), which is the lowest value reported for a MOF-based CORMA to date.
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| 9. |
- Cho, Jung, et al.
(författare)
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EMM-25 : The Structure of Two-Dimensional 11 x 10 Medium-Pore Borosilicate Zeolite Unraveled Using 3D Electron Diffraction
- 2021
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 33:11, s. 4146-4153
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Tidskriftsartikel (refereegranskat)abstract
- The structure of the novel medium-pore borosilicate zeolite EMM-25 has been determined by continuous rotation electron diffraction (cRED). EMM-25 crystallizes in the space group Cmcm with unit cell parameters a = 11.055, b = 22.912, and c = 24.914 angstrom and a composition of IC4H8(C11H25N)(2)I (2)[Si112.5B3.5O232]. The EMM-25 framework possesses a two-dimensional channel system composed of 10-ring channels connected via 11-ring windows. Its channel system is analogous to that of the medium-pore zeolite NU-87 framework but with 11- rather than 12-ring windows, suggesting a different shape selectivity. EMM-25 was first obtained using 1,4-bis(N-methyl-N,N-dihexylammonium)butane as an organic structure directing agent (OSDA). Based on a molecular docking study of the OSDA within the pores of the determined framework structure, a new ammonium dication OSDA with an improved fit was devised. By using this new OSDA, the synthesis time was reduced 80%, from 52 to just 10 days. Furthermore, cRED data revealed a structural disorder of the EMM-25 framework present as swinging zigzag chains. The introduction of the disorder, which is a consequence of geometry relaxation, was crucial for an accurate structure refinement. Lastly, the cRED data from as-made EMM-25 showed residual potential consistent with the location of the OSDA position determined from the Rietveld refinement, concluding a complete refinement of the as-made structure based on the cRED data.
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| 10. |
- Cichocka, Magdalena Ola, et al.
(författare)
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A Porphyrinic Zirconium Metal-Organic Framework for Oxygen Reduction Reaction : Tailoring the Spacing between Active-Sites through Chain-Based Inorganic Building Units
- 2020
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:36, s. 15386-15395
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Tidskriftsartikel (refereegranskat)abstract
- The oxygen reduction reaction (ORR) is central in carbon-neutral energy devices. While platinum group materials have shown high activities for ORR, their practical uses are hampered by concerns over deactivation, slow kinetics, exorbitant cost, and scarce nature reserve. The low cost yet high tunability of metal-organic frameworks (MOFs) provide a unique platform for tailoring their characteristic properties as new electrocatalysts. Herein, we report a new concept of design and present stable Zr-chain-based MOFs as efficient electrocatalysts for ORR. The strategy is based on using Zr-chains to promote high chemical and redox stability and, more importantly, tailor the immobilization and packing of redox active-sites at a density that is ideal to improve the reaction kinetics. The obtained new electrocatalyst, PCN-226, thereby shows high ORR activity. We further demonstrate PCN-226 as a promising electrode material for practical applications in rechargeable Zn-air batteries, with a high peak power density of 133 mW cm(-2). Being one of the very few electrocatalytic MOFs for ORR, this work provides a new concept by designing chain-based structures to enrich the diversity of efficient electrocatalysts and MOFs.
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