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103 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3, 4, 5, 6, 7, 8 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I04-Macromolecular Crystallography	The development of non‐hydrolysable oligosaccharide activity‐based inactivators for endoglycanases: A case study on a‐1,6 mannanases Hermen S. Overkleeft , Sybrin Schröder , Wendy Offen , Alexandra Males , Yi Jin , Casper De Boer , Jacopo Enotarpi , Gijs Van Der Marel , Bogdan Florea , Jeroen Codée , Gideon Davies Chemistry – A European Journal DOI: 10.1002/chem.202101255 Diamond Proposal Number(s): [13587, 18598] Show Abstract ▼ Abstract: There is a vast genomic resource for enzymes active on carbohydrates. Lagging far behind, however, are functional chemical tools for the rapid characterization of carbohydrate‐active enzymes. Activity‐based probes (ABPs) offer one chemical solution to these issues with ABPs based upon cyclophellitol epoxide and aziridine covalent and irreversible inhibitors representing a potent and widespread approach. Such inhibitors for enzymes active on polysaccharides are potentially limited by the requirement for several glycosidic bonds, themselves substrates for the enzyme targets. Here we show that non‐hydrolysable trisaccharide can be synthesized and applied even to enzymes with challenging subsite requirements. We find that incorporation of carbasugar moieties, which we accomplished by cuprate‐assisted regioselective trans‐diaxial epoxide opening of carba‐mannal we synthesised for this purpose, yields inactivators that act as powerful activity‐based inhibitors for a‐1,6 endo‐mannanases. 3‐D structures at 1.35 – 1.47 Å resolutions confirm the design rationale and binding to the enzymatic nucleophile. Carbasugar oligosaccharide cyclophellitols offer a powerful new approach for the design of robust endoglycosidase inhibitors, while the synthesis procedures presented here should allow adaptation towards activity‐based endoglycosidase probes as well as configurational isosteres targeting other endoglycosidase families.	Apr 2021
I11-High Resolution Powder Diffraction I19-Small Molecule Single Crystal Diffraction	Inherent ethyl acetate selectivity in a trianglimine molecular solid Donglin He , Chengxi Zhao , Linjiang Chen , Marc Little , Samantha Chong , Rob Clowes , Katherine Mckie , Mark Roper , Graeme Day , Ming Liu , Andrew Cooper Chemistry – A European Journal DOI: 10.1002/chem.202101510 Diamond Proposal Number(s): [21726, 17193] Show Abstract ▼ Abstract: Ethyl acetate is an important chemical raw material and solvent. It is also a key volatile organic compound in the brewing industry and a marker for lung cancer. Materials that are highly selective toward ethyl acetate are needed for its separation and detection. Here, we report a trianglimine macrocycle ( TAMC ) that selectively adsorbs ethyl acetate by forming a solvate. Crystal structure prediction showed this to be the lowest energy solvate structure available. This solvate leaves a metastable, ‘templated’ cavity after solvent removal. Adsorption and breakthrough experiments confirmed that imprinted TAMC has adequate adsorption kinetics to separate ethyl acetate from azeotropic mixtures with ethanol, which is a challenging and energy‐intensive industrial separation.	Apr 2021
I19-Small Molecule Single Crystal Diffraction	Controlled synthesis of large single crystals of metal‐organic framework CPO‐27‐Ni prepared by a modulation approach: in situ single crystal X‐ray diffraction studies Simon Maximilian Vornholt , Caroline Elliott , Cameron Rice , Samantha Russell , Peter J. Kerr , Daniel N. Rainer , Michal Mazur , Mark R. Warren , Paul S. Wheatley , Russell E. Morris Chemistry – A European Journal DOI: 10.1002/chem.202100528 Diamond Proposal Number(s): [24028] Open Access Show Abstract ▼ Abstract: The size of single crystals of the metal-organic framework CPO-27-Ni was incrementally increased through a series of modulated syntheses. A novel linker modulated synthesis using 2,5-dihydroxyterephthalic acid and the isomeric ligand 4,6-dihydroxyisophthalic acid yielded large single crystals of CPO-27-Ni (~70 µm). All materials proved high crystallinity and phase pure through powder X-ray diffraction, electron microscopy methods, thermogravimetric, and compositional analysis. For the first time single crystal structure analyses were carried out on CPO-27-Ni. High BET surface areas and nitric oxide (NO) release efficiencies were recorded for all materials. Large single crystals of CPO-27-Ni showed a prolonged NO release and proved suitable for in situ single crystal diffraction experiments to follow the NO adsorption. An efficient activation protocol was developed, leading to a dehydrated structure after just 4 h, which subsequently was NO-loaded, giving a first NO loaded single crystal structural model of CPO-27-Ni.	Mar 2021
	Surface engineering strategy using urea to improve the rate performance of Na2Ti3O7 in Na‐ion batteries Sara I. R. Costa , Yong‐seok Choi , Alistair J. Fielding , Andrew J. Naylor , John M. Griffin , Zdeněk Sofer , David O. Scanlon , Nuria Tapia-Ruiz Chemistry – A European Journal 27, 3875 - 3886 DOI: 10.1002/chem.v27.11 Open Access Show Abstract ▼ Abstract: Na2Ti3O7 (NTO) is considered a promising anode material for Na‐ion batteries due to its layered structure with an open framework and low and safe average operating voltage of 0.3 V vs. Na+/Na. However, its poor electronic conductivity needs to be addressed to make this material attractive for practical applications among other anode choices. Here, we report a safe, controllable and affordable method using urea that significantly improves the rate performance of NTO by producing surface defects such as oxygen vacancies and hydroxyl groups, and the secondary phase Na2Ti6O13. The enhanced electrochemical performance agrees with the higher Na+ ion diffusion coefficient, higher charge carrier density and reduced bandgap observed in these samples, without the need of nanosizing and/or complex synthetic strategies. A comprehensive study using a combination of diffraction, microscopic, spectroscopic and electrochemical techniques supported by computational studies based on DFT calculations, was carried out to understand the effects of this treatment on the surface, chemistry and electronic and charge storage properties of NTO. This study underscores the benefits of using urea as a strategy for enhancing the charge storage properties of NTO and thus, unfolding the potential of this material in practical energy storage applications.	Feb 2021
B18-Core EXAFS	Solvent‐dependent growth and stabilization mechanisms of surfactant‐free colloidal Pt nanoparticles Jonathan Quinson , Sarah Neumann , Laura Kacenauskaite , Jan Bucher , Jacob J. K. Kirkensgaard , Søren B. Simonsen , Luise Theil Kuhn , Alessandro Zana , Tom Vosch , Mehtap Oezaslan , Sebastian Kunz , Matthias Arenz Chemistry – A European Journal 26, 9012 - 9023 DOI: 10.1002/chem.202001553 Diamond Proposal Number(s): [12746] Show Abstract ▼ Abstract: Understanding the formation of nanoparticles (NPs) is key to develop materials by sustainable routes. The Co4CatTM process is a new synthesis of precious metal NPs in alkaline mono‐alcohols well‐suited to develop active nanocatalysts. The synthesis is ‘facile’, surfactant‐free and performed under mild conditions like low temperature. The reducing properties of the solvent are here shown to strongly influence the formation of Pt NPs. Based on the in situ formation of CO adsorbed on the NP surface by solvent oxidation, a model is proposed that accounts for the different growth and stabilization mechanisms as well as re‐dispersion properties of the surfactant‐free NPs in different solvents. Using in situ and ex situ characterizations, it is established that in methanol, a slow nucleation with a limited NP growth is achieved. In ethanol, a fast nucleation followed by continuous and pronounced particle sintering occurs.	Jul 2020
I12-JEEP: Joint Engineering, Environmental and Processing	Mechanistic in situ and ex situ studies of phase transformations in molecular co‐crystals Alexander Clout , Asma Buanz , Yuying Pang , Wing-mei Tsui , Dongpeng Yan , Gary Parkinson , Timothy Prior , Dejan-kresimir Bucar , Simon Gaisford , Gareth Williams Chemistry – A European Journal DOI: 10.1002/chem.202002267 Diamond Proposal Number(s): [12735] Open Access Show Abstract ▼ Abstract: Co‐crystallisation is widely explored as a route to improve the physical properties of pharmaceutical active ingredients, but little is known about the fundamental mechanisms of the process. Here we apply a novel hyphenated differential scanning calorimetry ‐ X‐ray diffraction technique to mimic the commercial hot melt extrusion process, and explore the heat‐induced synthesis of four new co‐crystals containing isonicotinamide. These comprise a 1:1 co‐crystal with 4‐hydroxybenzoic acid, 2:1 and 1:2 systems with 4‐hydroxyphenylacetic acid and a 1:1 crystal with 3,4‐dihydroxyphenylactic acid. The formation of co‐crystals during heating is complex mechanistically. In addition to co‐crystallisation, conversions between polymorphs of the co‐former starting materials and co‐crystal products are also observed. A subsequent study exploring the use of inkjet printing and milling to generate co‐crystals revealed that the synthetic approach has a major effect on the co‐crystal species and polymorphs produced.	Jul 2020
I19-Small Molecule Single Crystal Diffraction	Homo‐ and heterodinuclear arene‐linked osmium(II) and ruthenium(II) organometallics: probing the impact of metal variation on reactivity and biological activity Christopher S. Wilson , Timothy J. Prior , Jordon Sandland , Huguette Savoie , Ross W. Boyle , Benjamin Murray Chemistry – A European Journal DOI: 10.1002/chem.202002052 Show Abstract ▼ Abstract: Dinuclear metallodrugs offer much potential in the development of novel anticancer chemotherapeutics as a result of the distinct interactions possible with biomacromolecular targets and the unique biological activity that can result. Here, we describe the development of isostructural homodinuclear Os(II)‐Os(II) and heterodinuclear Os(II)‐Ru(II) organometallic complexes formed from the linking of the arene ligands of [M(η6‐arene)(C2O4)(PTA)] (M = Os/Ru; PTA = 1,3,5‐triaza‐7‐phosphaadamantane) units. Together with the known Ru(II)‐Ru(II) analogue, a chromatin‐modifying agent, we probed the impact of variation of the metal ions on the structure, reactivity and biological activity of these complexes. The complexes have been structurally characterised by X‐ray diffraction experiments, their stability and reactivity examined using 1H and 31P NMR spectroscopy and biological activity assessed, alongside mononuclear analogues, through MTT assays and cell cycle analysis (HT‐29 cell line). Results revealed high antiproliferative activity in each case with cell cycle profiles of the dinuclear complexes found to be similar to that for untreated cells, and similar but distinct profiles for the mononuclear complexes. These results indicate these complexes impact on cell viability predominantly through a non‐DNA damaging mechanism of action. The new Os(II)‐Os(II and Os(II)‐Ru(II) complexes reported here are further examples of a family of compounds operating via mechanism(s) of action atypical of the majority of metallodrugs, and which have potential as tools in chromatin research.	Jun 2020
I19-Small Molecule Single Crystal Diffraction	Luminescent anion sensing by transition‐metal dipyridylbenzene complexes incorporated into acyclic, macrocyclic and interlocked hosts Richard C. Knighton , Sophie Dapin , Paul D. Beer Chemistry – A European Journal 26, 5288 - 5296 DOI: 10.1002/chem.202000661 Diamond Proposal Number(s): [1858] Show Abstract ▼ Abstract: A series of novel acyclic, macrocyclic and mechanically interlocked luminescent anion sensors have been prepared by incorporation of the isophthalamide motif into dipyridylbenzene to obtain cyclometallated complexes of platinum(II) and ruthenium(II). Both the acyclic and macrocyclic derivatives 7⋅Pt, 7⋅Ru⋅PF6, 10⋅Pt and 10⋅Ru⋅PF6 are effective sensors for a range of halides and oxoanions. The near‐infra red emitting ruthenium congeners exhibited an increased binding strength compared to platinum due to the cationic charge and thus additional electrostatic interactions. Intramolecular hydrogen‐bonding between the dipyridylbenzene ligand and the amide carbonyls increases the preorganisation of both acyclic and macrocyclic metal derivatives resulting in no discernible macrocyclic effect. Interlocked analogues were also prepared, and preliminary luminescent chloride anion spectrometric titrations with 12⋅Ru⋅(PF6)2 demonstrate a marked increase in halide binding affinity due to the complementary chloride binding pocket of the [2]rotaxane. 1H NMR binding titrations indicate the interlocked dicationic receptor is capable of chloride recognition even in competitive 30 % aqueous mixtures.	Apr 2020
I19-Small Molecule Single Crystal Diffraction	Organic cage dumbbells Rebecca L. Greenaway , Valentina Santolini , Filip T. Szczypiński , Michael J. Bennison , Marc A. Little , Andrew Marsh , Kim E. Jelfs , Andrew I. Cooper Chemistry – A European Journal 26, 3718 - 3722 DOI: 10.1002/chem.201905623 Diamond Proposal Number(s): [21726] Show Abstract ▼ Abstract: Molecular dumbbells with organic cage capping units were synthesised via a multi‐component imine condensation between a tri‐topic amine and di‐ and tetra‐topic aldehydes. This is an example of self‐sorting, which can be rationalised by computational modelling.	Mar 2020
I03-Macromolecular Crystallography I04-1-Macromolecular Crystallography (fixed wavelength) I04-Macromolecular Crystallography I24-Microfocus Macromolecular Crystallography	Iron biomineral growth from the initial nucleation seed in L‐ferritin Silvia Ciambellotti , Cecilia Pozzi , Stefano Mangani , Paola Turano Chemistry – A European Journal DOI: 10.1002/chem.202000064 Diamond Proposal Number(s): [15832, 21741] Show Abstract ▼ Abstract: X‐ray structures of homopolymeric human L‐ferritin and horse spleen ferritin were solved by freezing protein crystals at different time intervals after exposure to a ferric salt and revealed the growth of an octa‐nuclear iron cluster on the inner surface of the protein cage with a key role played by some glutamate residues. An atomic resolution view of how the cluster formation develops starting from a (μ 3 ‐oxo)tris[(μ 2 ‐glutamato‐κO:κO′)](glutamato‐κO)(diaquo)triiron(III) seed is provided. The results support the idea that iron biomineralization in ferritin is a process initiating at the level of the protein surface, capable of contributing coordination bonds and electrostatic guidance.	Feb 2020

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