I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[28766, 36069]
Open Access
Abstract: The assembly of metal–organic cages is governed by metal ion coordination preferences and the geometries of the typically rigid and planar precursor ligands. PdnL2n cages are among the most structurally diverse, with subtle differences in the metal–ligand coordination vectors resulting in drastically different assemblies, however almost all rely on rigid aromatic linkers to avoid the formation of intractable mixtures. Here we exploit the inverse electron-demand Diels–Alder (IEDDA) reaction between tetrazine linker groups and alkene reagents to trigger structural changes induced by post-assembly modification. The structure of the 1,4-dihydropyridazine produced by IEDDA (often an afterthought in click chemistry) is crucial; its two sp3 centers increase flexibility and nonplanarity, drastically changing the range of accessible coordination vectors. This triggers an initial Pd4L8 tetrahedral cage to transform into different Pd2L4 lantern cages, with both the transformation extent (thermodynamics) and rate (kinetics) dependent on the alkene dienophile selected. With cyclopentene, the unsymmetrical 1,4-dihydropyridazine ligands undergo integrative sorting in the solid state, with both head-to-tail orientation and enantiomer selection, leading to a single isomer from the 39 possible. This preference is rationalized through entropy, symmetry, and hydrogen bonding. Subsequent oxidation of the 1,4-dihydropyridazine to the aromatic pyridazine rigidifies the ligands, restoring planarity. The oxidized ligands no longer fit in the lantern structure, inducing further structural transformations into Pd4L8 tetrahedra and Pd3L6 double-walled triangles. The concept of controllable addition of limited additional flexibility and then its removal through well-defined reactivity we envisage being of great interest for structural transformations of any class of supramolecular architecture.
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Sep 2024
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B16-Test Beamline
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Diamond Proposal Number(s):
[14099]
Open Access
Abstract: Material extrusion additive manufacturing (AM) has gradually become a dominant technology for the fabrication of complex-designed thermoplastic polymers that require a higher level of control over the morphological and mechanical properties. The polymer internal crystal structure formed during the AM process can present significant impacts on the mechanical properties of the individual filaments, as well as the whole structure. Currently, limited details are known about the crystal structure evolution during the material extrusion AM processes of polymers. A novel in situ synchrotron X-ray diffraction (XRD) experimental configuration was developed enabling us to capture the material evolution data throughout the extrusion AM process. The in situ time-resolved data was analysed to reveal nucleation and crystallization sequences during the continuous deposition, with the aid of both complimentary numerical simulations and post-process (ex situ) characterisations. The thermal simulations supported the prediction of the filament temperature profile over time and location during the AM process, while ex situ characterisations validated the correlation between polymer crystallinity (resulting from printing parameters) and corresponding mechanical properties. The results obtained from varied process parameters suggest that the processing temperature has a dominant influence on the crystal microstructure evolution compared to the deposition velocity. A lower processing temperature just above the melting temperature permitted favourable crystallization conditions. The overall analysis demonstrated prospects for enhancing polymer AM, to engineering mechanically hierarchical structures through correlative investigations.
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Sep 2024
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Shengzhe
Ding
,
Dario Luis
Fernandez Ainaga
,
Min
Hu
,
Boya
Qiu
,
Ushna
Khalid
,
Carmine
D’agostino
,
Xiaoxia
Ou
,
Ben
Spencer
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Xiangli
Zhong
,
Yani
Peng
,
Nicole
Hondow
,
Constantinos
Theodoropoulos
,
Yilai
Jiao
,
Christopher
Parlett
,
Xiaolei
Fan
Open Access
Abstract: Spatial control over features within multifunctional catalysts can unlock efficient one-pot cascade reactions, which are themselves a pathway to aviation biofuels via hydrodeoxygenation. A synthesis strategy that encompasses spatial orthogonality, i.e., one in which different catalytic species are deposited exclusively within discrete locations of a support architecture, is one solution that permits control over potential interactions between different sites and the cascade process. Here, we report a Pd doped hierarchical zeolite, in which Pd nanoparticles are selectively deposited within the mesopores, while acidity is retained solely within the micropores of ZSM-5. This spatial segregation facilitates hydrodeoxygenation while suppressing undesirable decarboxylation and decarbonation, yielding significant enhancements in activity (30.6 vs 3.6 moldodecane molPd−1 h−1) and selectivity (C12:C11 5.2 vs 1.9) relative to a conventionally prepared counterpart (via wet impregnation). Herein, multifunctional material design can realise efficient fatty acid hydrodeoxygenation, thus advancing the field and inspiring future developments in rationalised catalyst design.
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Sep 2024
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[34800]
Open Access
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.
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Sep 2024
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I21-Resonant Inelastic X-ray Scattering (RIXS)
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Changwei
Zou
,
Jaewon
Choi
,
Qizhi
Li
,
Shusen
Ye
,
Chaohui
Yin
,
Mirian
Garcia-Fernandez
,
Stefano
Agrestini
,
Qingzheng
Qiu
,
Xinqiang
Cai
,
Qian
Xiao
,
Xingjiang
Zhou
,
Ke-Jin
Zhou
,
Yayu
Wang
,
Yingying
Peng
Diamond Proposal Number(s):
[28855]
Open Access
Abstract: How Cooper pairs form and condense has been the main challenge in the physics of copper-oxide high-temperature superconductors. Great efforts have been made in the ‘underdoped’ region of the phase diagram, through doping a Mott insulator or cooling a strange metal. However, there is still no consensus on how superconductivity emerges when electron-electron correlations dominate and the Fermi surface is missing. To address this issue, here we carry out high-resolution resonant inelastic X-ray scattering and scanning tunneling microscopy studies on prototype cuprates Bi2Sr2Ca0.6Dy0.4Cu2O8+δ near the onset of superconductivity, combining bulk and surface, momentum- and real-space information. We show that an incipient charge order exists in the antiferromagnetic regime down to 0.04 holes per CuO2 unit, entangled with a particle-hole asymmetric pseudogap. The charge order induces an intensity anomaly in the bond-buckling phonon branch, which exhibits an abrupt increase once the system enters the superconducting dome. Our results suggest that the Cooper pairs grow out of a charge-ordered insulating state, and then condense accompanied by an enhanced interplay between charge excitations and electron-phonon coupling.
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Sep 2024
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Krios I-Titan Krios I at Diamond
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Victoria A.
Avanzato
,
Trenton
Bushmaker
,
Kasopefoluwa Y.
Oguntuyo
,
Claude Kwe
Yinda
,
Helen M. E.
Duyvesteyn
,
Robert
Stass
,
Kimberly
Meade-White
,
Rebecca
Rosenke
,
Tina
Thomas
,
Neeltje
Van Doremalen
,
Greg
Saturday
,
Katie J.
Doores
,
Benhur
Lee
,
Thomas A.
Bowden
,
Vincent J.
Munster
Diamond Proposal Number(s):
[20223]
Abstract: Nipah virus (NiV) is a highly pathogenic paramyxovirus capable of causing severe respiratory and neurologic disease in humans. Currently, there are no licensed vaccines or therapeutics against NiV, underscoring the urgent need for the development of countermeasures. The NiV surface-displayed glycoproteins, NiV-G and NiV-F, mediate host cell attachment and fusion, respectively, and are heavily targeted by host antibodies. Here, we describe a vaccination-derived neutralizing monoclonal antibody, mAb92, that targets NiV-F. Structural characterization of the Fab region bound to NiV-F (NiV-F–Fab92) by cryo-electron microscopy analysis reveals an epitope in the DIII domain at the membrane distal apex of NiV-F, an established site of vulnerability on the NiV surface. Further, prophylactic treatment of hamsters with mAb92 offered complete protection from NiV disease, demonstrating beneficial activity of mAb92 in vivo. This work provides support for targeting NiV-F in the development of vaccines and therapeutics against NiV.
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Sep 2024
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I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Pragya
Parashara
,
Bethan
Medina-Pritchard
,
Maria Alba
Abad
,
Paula
Sotelo-Parrilla
,
Reshma
Thamkachy
,
David
Grundei
,
Juan
Zou
,
Christos
Spanos
,
Chandni Natalia
Kumar
,
Claire
Basquin
,
Vimal
Das
,
Zhaoyue
Yan
,
Asma Abdullah
Al-Murtadha
,
David A.
Kelly
,
Toni
Mchugh
,
Axel
Imhof
,
Juri
Rappsilber
,
A. Arockia
Jeyaprakash
Diamond Proposal Number(s):
[25233]
Abstract: Accurate chromosome segregation requires the attachment of microtubules to centromeres, epigenetically defined by the enrichment of CENP-A nucleosomes. During DNA replication, CENP-A nucleosomes undergo dilution. To preserve centromere identity, correct amounts of CENP-A must be restored in a cell cycle–controlled manner orchestrated by the Mis18 complex (Mis18α-Mis18β-Mis18BP1). We demonstrate here that PLK1 interacts with the Mis18 complex by recognizing self-primed phosphorylations of Mis18α (Ser54) and Mis18BP1 (Thr78 and Ser93) through its Polo-box domain. Disrupting these phosphorylations perturbed both centromere recruitment of the CENP-A chaperone HJURP and new CENP-A loading. Biochemical and functional analyses showed that phosphorylation of Mis18α and PLK1 binding were required to activate Mis18α-Mis18β and promote Mis18 complex-HJURP interaction. Thus, our study reveals key molecular events underpinning the licensing role of PLK1 in ensuring accurate centromere inheritance.
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Sep 2024
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Xiao
Wang
,
Jie
Zhang
,
Zhao
Pan
,
Dabiao
Lu
,
Maocai
Pi
,
Xubin
Ye
,
Cheng
Dong
,
Jie
Chen
,
Kai
Chen
,
Florin
Radu
,
Sonia
Francoual
,
Stefano
Agrestini
,
Zhiwei
Hu
,
Chun-Fu
Chang
,
Arata
Tanaka
,
Kazunari
Yamaura
,
Yao
Shen
,
Youwen
Long
Abstract: By means of X-ray absorption spectroscopic studies, both experimentally and theoretically, we investigated the magnetic properties of the transition-metal-only double perovskite oxide Mn2CoReO6, which experiences an antiferromagnetic transition at TN = 93 K, whereas it holds a considerable net moment at low temperature. Internal exchange fields against the applied magnetic field for all the transition metal ions were identified, providing a microscopic insight into the intrasite antiferromagnetic couplings. Nevertheless, parallelly oriented canted spins of the Mn, Co, and Re cations were observed. In particularly, the Mn and Co cations hold considerable canting moments, which can be ascribed to the competition between the ferromagnetic intersite and antiferromagnetic intrasite magnetic interactions. Moreover, a spin-valve-type magnetoresistance was observed below the TN. The concurrence of the magnetoresistance effect and the antiferromagnetic semiconductive nature make Mn2CoReO6 a promising candidate for high-speed and energy-saving spintronics applications.
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Sep 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Marcin W.
Orzech
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Francesco
Mazzali
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Arturas
Adomkevicius
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Mauro
Coduri
,
Yubiao
Niu
,
James D.
Mcgettrick
,
Philip A.
Chater
,
Laura
Cabo-Fernandez
,
Laurence J.
Hardwick
,
Lorenzo
Malavasi
,
Serena
Margadonna
Diamond Proposal Number(s):
[19325]
Open Access
Abstract: Sodium-ion batteries represent a sustainable and cost-effective solution for grid-scale energy storage. However, the reliance on cathode materials containing scarce transition metals currently limits their wider adoption. Carbonaceous materials present an environmentally sustainable and economically viable alternative. This study investigates application of reduced graphene oxide as a cathode active material. Detailed analysis of the storage mechanism and its dependency on the morphological and chemical structure, revealed that the key factors responsible for high capacity and long cycle life are the open structure of graphene sheets and the presence of functional oxygen and nitrogen groups. Good understanding of the mechanism allowed optimisation of cycling conditions in a proof-of-concept all-carbon full cell incorporating reduced graphene oxide and hard carbon as cathode and anode, respectively. The system displays good energy density (80 Wh kg-1) and remarkable stability over 500 cycles. The gained insights will support rational design of more efficient carbonaceous electrodes.
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Sep 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[35994]
Open Access
Abstract: Nucleation plays an important role in crystallization outcomes, but it is still poorly understood because it occurs on short timescales and small size scales. Consequently, nucleation mechanisms are still challenging to comprehend and predict. Gaining a better understanding, and potentially control, over nucleation pathways, can significantly aid toward more consistent and targeted crystallization outcomes. To achieve this, facile methods that allow for an accurate depiction and analysis of nucleus-sized clusters are needed. Herein, the use of crystalline metal–organic frameworks (MOFs) is reported to entrap clusters of small organic molecules, allowing for an accurate representation of the size and shape of the confined clusters via single-crystal X-Ray diffraction analysis. This is realized by synthesizing high-quality single crystals of lanthanum-based MOFs, which provides well-defined pore spaces for the encapsulation of guest molecules. The results show that the size and shape of the guest molecular clusters within MOFs significantly differ from their bulk equivalents, suggesting that this method can also be used toward discovering novel polymorphs. Additionally, the findings indicate that these small molecular clusters form via intermolecular interactions that do not always dominate the bulk packing, shedding new light on the initial molecular aggregation mechanisms of precritical nuclei.
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Sep 2024
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