I19-Small Molecule Single Crystal Diffraction
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Mariya
Aleksich
,
Yeongsu
Cho
,
Daniel W.
Paley
,
Maggie C.
Willson
,
Hawi N.
Nyiera
,
Patience A.
Kotei
,
Vanessa
Oklejas
,
David W.
Mittan-Moreau
,
Elyse A.
Schriber
,
Kara
Christensen
,
Ichiro
Inoue
,
Shigeki
Owada
,
Kensuke
Tono
,
Michihiro
Sugahara
,
Satomi
Inaba-Inoue
,
Mohammad
Vakili
,
Christopher J.
Milne
,
Fabio
Dallantonia
,
Dmitry
Khakhulin
,
Fernando
Ardana-Lamas
,
Frederico
Lima
,
Joana
Valerio
,
Huijong
Han
,
Tamires
Gallo
,
Hazem
Yousef
,
Oleksii
Turkot
,
Ivette J. Bermudez
Macias
,
Thomas
Kluyver
,
Philipp
Schmidt
,
Luca
Gelisio
,
Adam R.
Round
,
Yifeng
Jiang
,
Doriana
Vinci
,
Yohei
Uemura
,
Marco
Kloos
,
Adrian P.
Mancuso
,
Mark
Warren
,
Nicholas K.
Sauter
,
Jing
Zhao
,
Tess
Smidt
,
Heather J.
Kulik
,
Sahar
Sharifzadeh
,
Aaron S.
Brewster
,
J. Nathan
Hohman
Diamond Proposal Number(s):
[35300]
Abstract: X-ray free electron laser (XFEL) microcrystallography and synchrotron single-crystal crystallography are used to evaluate the role of organic substituent position on the optoelectronic properties of metal–organic chalcogenolates (MOChas). MOChas are crystalline 1D and 2D semiconducting hybrid materials that have varying optoelectronic properties depending on composition, topology, and structure. While MOChas have attracted much interest, small crystal sizes impede routine crystal structure determination. A series of constitutional isomers where the aryl thiol is functionalized by either methoxy or methyl ester are solved by small molecule serial femtosecond X-ray crystallography (smSFX) and single crystal rotational crystallography. While all the methoxy examples have a low quantum yield (0-1%), the methyl ester in the ortho position yields a high quantum yield of 22%. The proximity of the oxygen atoms to the silver inorganic core correlates to a considerable enhancement of quantum yield. Four crystal structures are solved at a resolution range of 0.8–1.0 Å revealing a collapse of the 2D topology for functional groups in the 2- and 3- positions, resulting in needle-like crystals. Further analysis using density functional theory (DFT) and many-body perturbation theory (MBPT) enables the exploration of complex excitonic phenomena within easily prepared material systems.
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Dec 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[26879]
Abstract: Cage-catenanes are chemical constructs where two or more cage-like molecules or assemblies are mechanically interlocked together. We report a new class of cage-catenanes where dimeric metal-organic cage-catenanes are linked into larger assemblies through additional bridging metal chloride links. These crystalline materials are obtained from the reaction of tris(nicotinoyl)cyclotriguaiacylene (L1) with Cu(II) salts, and all feature a tetramer of cages where two {Cu3(L1)2(X)6} cages (X = anion) are mechanically interlocked, and link to each other and to another {Cu3(L1)2(X)6}2 cage-catenane through a planar, linear tetranuclear {Cu4(μ−Cl)6Cl2} cluster. The complex of discrete tetrameric {Cu3(L1)2(X)6}4 assemblies (dimers of cage-catenanes) transforms through solvent-exchange processes to 1D coordination chain structures through additional {Cu2(μ−Cl)2} bridges between the tetrameric {Cu3(L1)2(X)6}4 assemblies. Complex [Cu6(L1)4Cl12(H2O)3]·(H2O)·15(DMF) C2 features a 2D coordination network of 63 topology linked through three different Cu(II) clusters, namely {Cu4(μ−Cl)6}, {Cu2(μ−Cl)2} and a rare linear {Cu2(μ-Cl)} linkage. Break-down of C2 in water likely proceeds through hydrolysis of this unusual linear Cu-Cl-Cl bond.
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Dec 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[29890]
Open Access
Abstract: A key feature of coordination cages is the dynamic nature of their coordinative bonds, which facilitates the synthesis of complex polyhedral structures and their post-assembly modification. However, this dynamic nature can limit cage stability. Increasing cage robustness is important for real-world use cases. Here we introduce a double-bridging strategy to increase cage stability, where designed pairs of bifunctional subcomponents combine to generate rectangular tetratopic ligands within pseudo-cubic Zn8L6 cages. These cages withstand transmetalation, the addition of competing ligands, and nucleophilic imines, under conditions where their single-bridged congeners decompose. Our approach not only increases the stability and robustness of the cages while maintaining their polyhedral structure, but also enables the incorporation of additional functional units in proximity to the cavity. The double-bridging strategy also facilitates the synthesis of larger cages, which are inaccessible as single-bridged congeners.
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Nov 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[35994]
Open Access
Abstract: Oxoboranes (R-BO) are transient species that rapidly trimerise to form boroxines. To date, the only method used to stabilise oxoboranes is to add a Lewis base, but this forms a three-coordinate at boron oxoborane that has a different bonding/reactivity profile. Herein we report a base-free, two-coordinate oxoborane that is isolated as a Lewis adduct with AlCl3. This species, Mes*BO-AlCl3 (Mes* = 2,4,6-tBu-C6H2), has a ν11ΒΟ stretching frequency of 1843 cm-1, indicating a strong BO bond. Computational analysis indicates this is due to a highly polarised BO bonding interaction combined with modest BO multiple bond character. While the polarisation of the BO bond on AlCl3 coordination enhances the Lewis acidity at boron it also reduces the basicity at oxygen and the latter is key to accessing a base-free oxoborane. Finally, this oxoborane reacts with PhN3 in a unique way to form an unprecedented boron heterocycle.
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Nov 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[33014, 35357]
Open Access
Abstract: The increasing availability of ultrabright Light Sources is facilitating the study of smaller crystals at faster timescales but with an increased risk of severe X-ray damage, leading to developments in multi-crystal methods such as serial crystallography (SX). SX studies on crystals with small unit cells are challenging as very few reflections are recorded in a single data image, making it difficult to determine the orientation matrix for each crystal and thus preventing the combination of the data from all crystals for structure solution. We herein present a Small-Rotative Fixed-Target Serial Synchrotron Crystallography (SR-FT-SSX) methodology, in which rotation of the serial target through a small diffraction angle at each crystal delivers high-quality data, facilitating ab initio unit cell determination and atomic-scale structure solution. The method is benchmarked using microcrystals of the small-molecule photoswitch sodium nitroprusside dihydrate, obtaining complete data to dmin = 0.6 Å by combining just 66 partial datasets selected against rigorous quality criteria.
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Nov 2024
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I19-Small Molecule Single Crystal Diffraction
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Zhonghang
Chen
,
Peiyu
Fang
,
Jiangnan
Li
,
Xue
Han
,
Wenhao
Huang
,
Wenyue
Cui
,
Zhiwei
Liu
,
Mark R.
Warren
,
David
Allan
,
Peng
Cheng
,
Sihai
Yang
,
Wei
Shi
Diamond Proposal Number(s):
[36394]
Open Access
Abstract: Due to almost identical boiling points of benzene and cyclohexane, the extraction of trace benzene from cyclohexane is currently performed via the energy-intensive extractive distillation method. Their adsorptive separation by porous materials is hampered by their similar dimensions. Metal-organic frameworks (MOFs) with versatile pore environments are capable of molecular discrimination, but the separation of trace substrates in liquid-phase remains extremely challenging. Herein, we report a robust MOF (NKU-300) with triangular channels decorated with crown ether that can discriminate trace benzene from cyclohexane, exhibiting an unprecedented selectivity of 8615(10) for the mixture of benzene/cyclohexane (v/v = 1/1000). Remarkably, NKU-300 demonstrates exceptional selectivities for the extraction of benzene from cyclohexane over a wide range of concentrations of 0.1%–50% with ultrafast sorption kinetics and excellent stability. Single-crystal X-ray diffraction and computational modelling reveal that multiple supramolecular interactions cooperatively immobilise benzene molecules in the triangular channel, enabling the superior separation performance. This study will promote the application of advanced sorbents with tailored binding sites for challenging industrial separations.
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Oct 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[34893]
Open Access
Abstract: The experimental exploration of the chemical space of crystalline materials, especially metal–organic frameworks (MOFs), requires multiparameter control of a large set of reactions, which is unavoidably time-consuming and labor-intensive when performed manually. To accelerate the rate of material discovery while maintaining high reproducibility, we developed a machine learning algorithm integrated with a robotic synthesis platform for closed-loop exploration of the chemical space for polyoxometalate-scaffolding metal–organic frameworks (POMOFs). The eXtreme Gradient Boosting (XGBoost) model was optimized by using updating data obtained from the uncertainty feedback experiments and a multiclass classification extension based on the POMOF classification from their chemical constitution. The digital signatures for the robotic synthesis of POMOFs were represented by the universal chemical description language (χDL) to precisely record the synthetic steps and enhance the reproducibility. Nine novel POMOFs including one with mixed ligands derived from individual ligands through the imidization reaction of POM amine derivatives with various aldehydes have been discovered with a good repeatability. In addition, chemical space maps were plotted based on the XGBoost models whose F1 scores are above 0.8. Furthermore, the electrochemical properties of the synthesized POMOFs indicate superior electron transfer compared to the molecular POMs and the direct effect of the ratio of Zn, the type of ligands used, and the topology structures in POMOFs for modulating electron transfer abilities.
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Oct 2024
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I19-Small Molecule Single Crystal Diffraction
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Gaël
Bastien
,
Dalibor
Repček
,
Adam
Eliáš
,
Andrej
Kancko
,
Quentin
Courtade
,
Tetiana
Haidamak
,
Maxim
Savinov
,
Viktor
Bovtun
,
Martin
Kempa
,
Karel
Carva
,
Michal
Vališka
,
Petr
Doležal
,
Marie
Kratochvílová
,
Sarah A.
Barnett
,
Petr
Proschek
,
Jan
Prokleška
,
Christelle
Kadlec
,
Petr
Kužel
,
Ross H.
Colman
,
Stanislav
Kamba
Diamond Proposal Number(s):
[33159]
Open Access
Abstract: The study of magnetic frustration in classical spin systems is motivated by the prediction and discovery of classical spin liquid states. These uncommon magnetic phases are characterized by a massive degeneracy of their ground state implying a finite magnetic entropy at zero temperature. While the classical spin liquid state is originally predicted in the Ising triangular lattice antiferromagnet in 1950, this state has never been experimentally observed in any triangular magnets. The discovery of an electric analogue of classical spin liquids on a triangular lattice of uniaxial electric dipoles in EuAl12O19 is reported here. This new type of frustrated antipolar phase is characterized by a highly-degenerate state at low temperature implying an absence of long-range antiferroelectric order, despite short-range antipolar correlations. Its dynamics are governed by a thermally activated process, slowing down upon cooling toward a complete freezing at zero temperature.
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Oct 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[30461]
Abstract: Pushed and pulled by competing interactions, molecules can self-assemble into complex structures. Using supramolecular self-assembly, we can synthesise materials with unique structures and function. However, predicting how molecules will assemble themselves, and controlling the reaction conditions to nudge them into forming a desirable structure, is challenging. Using porous cage molecules as building blocks for larger structures is an attractive prospect. Using a hierarchical approach embeds cage molecules and their useful properties into more complex structures with new functions. However, predicting and controlling the synthesis process becomes increasingly difficult. A team of researchers from the University of Liverpool, Herriot-Watt University, Imperial College London, the University of Southampton and East China University of Science and Technology has developed a hierarchical cage molecule that can adsorb other molecules, like carbon dioxide and sulfur hexafluoride. A key aspect of the project was using computer modelling to accurately predict how the precursor molecules would self-assemble into a new material. Their work, recently published in Nature Synthesis, suggests that computational predictions backed up by experimental studies could be a successful strategy for yielding more complex and interesting materials in the future.
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Oct 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[25064, 26668]
Open Access
Abstract: The crystalline sponge method has proven invaluable in the preparation and analysis of supramolecular host/guest complexes if the host can be obtained in a suitable crystalline form, allowing the analysis of guest binding modes inside host cavities which can inform other studies into processes such as catalysis. Here, we report the structures of a set of ten host/guest complexes using an octanuclear coordination cage host with a range of small-molecule neutral organic guests including four aromatic aldehydes and ketones, three cyclic lactams, and three epoxides. In all cases, the cavity-bound guests are anchored by a collection of CH•••O hydrogen-bonding interactions between an O atom on the guest and a convergent set of CH protons at a pocket on the cage interior surface. Depending on guest size and the presence of solvent molecules as additional guests, there may be one or two cavity-bound guests, with small aromatic guests forming π-stacked pairs. Some guests (the lactams) participate in additional NH•••F H-bonding interactions with surface-bound fluoroborate anions, which indicate the type of anion/guest interactions thought to be responsible for solution-phase catalytic reactions of bound guests.
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Oct 2024
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