ed There was an earthquake in Gwynedd yesterday - but you probably didn't feel the earth move - Daily Post By www.dailypost.co.uk Published On :: Sun, 05 Jan 2020 19:48:26 GMT There was an earthquake in Gwynedd yesterday - but you probably didn't feel the earth move Daily Post Full Article
ed Houses 'rattled' as minor earthquakes shake Shropshire - BBC News By www.bbc.co.uk Published On :: Tue, 15 Oct 2019 07:00:00 GMT Houses 'rattled' as minor earthquakes shake Shropshire BBC News Full Article
ed 'Surrey swarm' earthquakes not caused by nearby oil extraction, study suggests - Science Daily By www.sciencedaily.com Published On :: Tue, 27 Aug 2019 07:00:00 GMT 'Surrey swarm' earthquakes not caused by nearby oil extraction, study suggests Science Daily Full Article
ed Devon braced for aftershocks following earthquake - Devon Live By www.devonlive.com Published On :: Fri, 06 Dec 2019 08:00:00 GMT Devon braced for aftershocks following earthquake Devon Live Full Article
ed Second earthquake recorded this year in Northamptonshire - Northampton Chronicle and Echo By www.northamptonchron.co.uk Published On :: Sat, 04 Apr 2020 07:00:00 GMT Second earthquake recorded this year in Northamptonshire Northampton Chronicle and Echo Full Article
ed Surrey named as one of the UK's earthquake hotspots - Surrey Live By www.getsurrey.co.uk Published On :: Thu, 14 Nov 2019 08:00:00 GMT Surrey named as one of the UK's earthquake hotspots Surrey Live Full Article
ed Earthquake recorded off Cornwall coast - Cornwall Live By www.cornwalllive.com Published On :: Sun, 10 Nov 2019 08:00:00 GMT Earthquake recorded off Cornwall coast Cornwall Live Full Article
ed BGS Mineral Planning Factsheet updated - Agg-Net By www.agg-net.com Published On :: Mon, 08 Jul 2019 07:00:00 GMT BGS Mineral Planning Factsheet updated Agg-Net Full Article
ed Geologists discover hundreds of buried valleys throughout Britain - Press and Journal By www.pressandjournal.co.uk Published On :: Thu, 04 Jul 2019 07:00:00 GMT Geologists discover hundreds of buried valleys throughout Britain Press and Journal Full Article
ed Snowdonia earthquake confirmed by British Geological Survey - Daily Post By www.dailypost.co.uk Published On :: Mon, 09 Sep 2019 16:51:30 GMT Snowdonia earthquake confirmed by British Geological Survey Daily Post Full Article
ed Kendalian Dr Kent Brooks trained new director of British Geological Survey - The Westmorland Gazette By www.thewestmorlandgazette.co.uk Published On :: Fri, 19 Jul 2019 07:00:00 GMT Kendalian Dr Kent Brooks trained new director of British Geological Survey The Westmorland Gazette Full Article
ed Coronavirus: the week explained - 10 April - The Guardian By www.theguardian.com Published On :: Fri, 10 Apr 2020 11:11:36 GMT Coronavirus: the week explained - 10 April The Guardian Full Article
ed Ancient underwater landslides help Brit scientists predict tsunamis - Metro.co.uk By metro.co.uk Published On :: Fri, 24 Apr 2020 07:16:08 GMT Ancient underwater landslides help Brit scientists predict tsunamis Metro.co.uk Full Article
ed Explained: How coronavirus lockdown reduced Earth’s seismic noise levels - The Indian Express By indianexpress.com Published On :: Sun, 12 Apr 2020 18:31:06 GMT Explained: How coronavirus lockdown reduced Earth’s seismic noise levels The Indian Express Full Article
ed Why the UK's streets have turned silent during coronavirus lockdown - Express.co.uk By www.express.co.uk Published On :: Wed, 29 Apr 2020 07:00:00 GMT Why the UK's streets have turned silent during coronavirus lockdown Express.co.uk Full Article
ed UK sees notable reduction in seismic noise caused by human activity – experts - Aberdeen Evening Express By www.eveningexpress.co.uk Published On :: Fri, 24 Apr 2020 07:00:00 GMT UK sees notable reduction in seismic noise caused by human activity – experts Aberdeen Evening Express Full Article
ed Ancient underwater landslides help predict tsunami risk - Aberdeen Evening Express By www.eveningexpress.co.uk Published On :: Thu, 23 Apr 2020 07:00:00 GMT Ancient underwater landslides help predict tsunami risk Aberdeen Evening Express Full Article
ed Research Centre Finance Administrator job with UNIVERSITY OF LEEDS | 206139 - Times Higher Education (THE) By www.timeshighereducation.com Published On :: Thu, 07 May 2020 05:09:11 GMT Research Centre Finance Administrator job with UNIVERSITY OF LEEDS | 206139 Times Higher Education (THE) Full Article
ed Fossil believed to show squid-like creature attacking fish 200 million years ago - Aberdeen Evening Express By www.eveningexpress.co.uk Published On :: Wed, 06 May 2020 15:01:00 GMT Fossil believed to show squid-like creature attacking fish 200 million years ago Aberdeen Evening Express Full Article
ed Did the earth move for you? British Geological Survey has asked if Cumbrians felt an earth tremor last week - News & Star By www.newsandstar.co.uk Published On :: Sat, 02 May 2020 04:00:00 GMT Did the earth move for you? British Geological Survey has asked if Cumbrians felt an earth tremor last week News & Star Full Article
ed Crystallographic snapshots of the EF-hand protein MCFD2 complexed with the intracellular lectin ERGIC-53 involved in glycoprotein transport By scripts.iucr.org Published On :: 2020-04-29 The transmembrane intracellular lectin ER–Golgi intermediate compartment protein 53 (ERGIC-53) and the soluble EF-hand multiple coagulation factor deficiency protein 2 (MCFD2) form a complex that functions as a cargo receptor, trafficking various glycoproteins between the endoplasmic reticulum (ER) and the Golgi apparatus. It has been demonstrated that the carbohydrate-recognition domain (CRD) of ERGIC-53 (ERGIC-53CRD) interacts with N-linked glycans on cargo glycoproteins, whereas MCFD2 recognizes polypeptide segments of cargo glycoproteins. Crystal structures of ERGIC-53CRD complexed with MCFD2 and mannosyl oligosaccharides have revealed protein–protein and protein–sugar binding modes. In contrast, the polypeptide-recognition mechanism of MCFD2 remains largely unknown. Here, a 1.60 Å resolution crystal structure of the ERGIC-53CRD–MCFD2 complex is reported, along with three other crystal forms. Comparison of these structures with those previously reported reveal that MCFD2, but not ERGIC-53–CRD, exhibits significant conformational plasticity that may be relevant to its accommodation of various polypeptide ligands. Full Article text
ed Crystal structure of the nucleoid-associated protein Fis (PA4853) from Pseudomonas aeruginosa By scripts.iucr.org Published On :: 2020-04-29 Factor for inversion stimulation (Fis) is a versatile bacterial nucleoid-associated protein that can directly bind and bend DNA to influence DNA topology. It also plays crucial roles in regulating bacterial virulence factors and in optimizing bacterial adaptation to various environments. Fis from Pseudomonas aeruginosa (PA4853, referred to as PaFis) has recently been found to be required for virulence by regulating the expression of type III secretion system (T3SS) genes. PaFis can specifically bind to the promoter region of exsA, which functions as a T3SS master regulator, to regulate its expression and plays an essential role in transcription elongation from exsB to exsA. Here, the crystal structure of PaFis, which is composed of a four-helix bundle and forms a homodimer, is reported. PaFis shows remarkable structural similarities to the well studied Escherichia coli Fis (EcFis), including an N-terminal flexible loop and a C-terminal helix–turn–helix (HTH) motif. However, the critical residues for Hin-catalyzed DNA inversion in the N-terminal loop of EcFis are not conserved in PaFis and further studies are required to investigate its exact role. A gel-electrophoresis mobility-shift assay showed that PaFis can efficiently bind to the promoter region of exsA. Structure-based mutagenesis revealed that several conserved basic residues in the HTH motif play essential roles in DNA binding. These structural and biochemical studies may help in understanding the role of PaFis in the regulation of T3SS expression and in virulence. Full Article text
ed Structure-based screening of binding affinities via small-angle X-ray scattering By scripts.iucr.org Published On :: 2020-05-06 Protein–protein and protein–ligand interactions often involve conformational changes or structural rearrangements that can be quantified by solution small-angle X-ray scattering (SAXS). These scattering intensity measurements reveal structural details of the bound complex, the number of species involved and, additionally, the strength of interactions if carried out as a titration. Although a core part of structural biology workflows, SAXS-based titrations are not commonly used in drug discovery contexts. This is because prior knowledge of expected sample requirements, throughput and prediction accuracy is needed to develop reliable ligand screens. This study presents the use of the histidine-binding protein (26 kDa) and other periplasmic binding proteins to benchmark ligand screen performance. Sample concentrations and exposure times were varied across multiple screening trials at four beamlines to investigate the accuracy and precision of affinity prediction. The volatility ratio between titrated scattering curves and a common apo reference is found to most reliably capture the extent of structural and population changes. This obviates the need to explicitly model scattering intensities of bound complexes, which can be strongly ligand-dependent. Where the dissociation constant is within 102 of the protein concentration and the total exposure times exceed 20 s, the titration protocol presented at 0.5 mg ml−1 yields affinities comparable to isothermal titration calorimetry measurements. Estimated throughput ranges between 20 and 100 ligand titrations per day at current synchrotron beamlines, with the limiting step imposed by sample handling and cleaning procedures. Full Article text
ed The crystal structure of the heme d1 biosynthesis-associated small c-type cytochrome NirC reveals mixed oligomeric states in crystallo By journals.iucr.org Published On :: The crystal structure of the c-type cytochrome NirC from Pseudomonas aeruginosa has been determined and reveals the simultaneous presence of monomers and 3D domain-swapped dimers in the same asymmetric unit. Full Article text
ed Crystal and solution structures of fragments of the human leucocyte common antigen-related protein By journals.iucr.org Published On :: The crystal and solution SAXS structures of a fragment of human leucocyte common antigen-related protein show that it is less flexible than the homologous proteins tyrosine phosphatase receptors δ and σ. Full Article text
ed Structural and thermodynamic analysis of interactions between death-associated protein kinase 1 and anthraquinones By journals.iucr.org Published On :: Death-associated protein kinase 1 (DAPK1) was found to form a complex with purpurin and the crystal structure of the complex was determined. Purpurin may be a good lead compound for for the discovery of inhibitors of DAPK1. Full Article text
ed Structure–function study of AKR4C14, an aldo-keto reductase from Thai Jasmine rice (Oryza sativa L. ssp. Indica cv. KDML105) By journals.iucr.org Published On :: Rice AKR in the apo structure reveals the ordered open conformation and its key residues which form the substrate channel wall and determine its substrate preference for straight-chain aldehydes. Full Article text
ed Macromolecular X-ray crystallography: soon to be a road less travelled? By journals.iucr.org Published On :: From the perspective of a young(ish) structural biologist who currently specialises in macromolecular X-ray crystallography, are the best years of crystallography over? Some evidence and hopefully thought-provoking analysis is presented here on the subject. Full Article text
ed Structure of Thermococcus litoralis Δ1-pyrroline-2-carboxylate reductase in complex with NADH and L-proline By journals.iucr.org Published On :: The paper reports the structure of a Δ1-pyrroline-2-carboxylate reductase from the archaeon Thermococcus litoralis, a key enzyme involved in the second step of trans-4-Hydroxy-L-proline metabolism, conserved in archaea, bacteria and humans. Full Article text
ed Redetermination of the crystal structure of BaTeO3(H2O), including the localization of the hydrogen atoms By scripts.iucr.org Published On :: 2019-05-31 The redetermination of the crystal structure of barium oxidotellurate(IV) monohydrate allowed the localization of the hydrogen atoms that were not determined in the previous study [Nielsen, Hazell & Rasmussen (1971). Acta Chem. Scand. 25, 3037–3042], thus making an unambiguous assignment of the hydrogen-bonding scheme possible. The crystal structure shows a layered arrangement parallel to (001), consisting of edge-sharing [BaO6(H2O)] polyhedra and flanked by isolated [TeO3] trigonal pyramids on the top and bottom. O—H⋯O hydrogen bonds of medium strength link adjacent layers along [001]. Full Article text
ed 6-Methyluracil: a redetermination of polymorph (II) By scripts.iucr.org Published On :: 2019-06-21 6-Methyluracil, C5H6N2O2, exists in two crystalline phases: form (I), monoclinic, space group P21/c [Reck et al. (1988). Acta Cryst. A44, 417–421] and form (II), monoclinic, space group C2/c [Leonidov et al. (1993). Russ. J. Phys. Chem. 67, 2220–2223]. The structure of polymorph (II) has been redetermined providing a significant increase in the precision of the derived geometric parameters. In the crystal, molecules form ribbons approximately running parallel to the c-axis direction through N—H⋯O hydrogen bonds. The radical differences observed between the crystal packing of the two polymorphs may be responsible in form (II) for an increase in the contribution of the polar canonical forms C—(O−)=N—H+ relative to the neutral canonical form C(=O)—N—H induced by hydrogen-bonding interactions. Full Article text
ed Crystal structure of a salt with a protonated sugar cation and a cobalt(II) complex anion: (GlcN–H, K)[Co(NCS)4]·2H2O By scripts.iucr.org Published On :: 2019-09-06 The title compound, d-(+)-glucosammonium potassium tetrathiocyanatocobaltate(II) dihydrate, K(C6H14NO5)[Co(NCS)4]·2H2O or (GlcNH)(K)[Co(NCS)4]·2H2O, has been obtained as a side product of an incomplete salt metathesis reaction of d-(+)-glucosamine hydrochloride (GlcN·HCl) and K2[Co(NCS)4]. The asymmetric unit contains a d-(+)-glucosammonium cation, a potassium cation, a tetraisothiocyanatocobalt(II) complex anion and two water molecules. The water molecules coordinate to the potassium cation, which is further coordinated via three short K+⋯SCN− contacts involving three [Co(NCS)4]2− complex anions and via three O atoms of two d-(+)-glucosammonium cations, leading to an overall eightfold coordination around the potassium cation. Hydrogen-bonding interactions between the building blocks consolidate the three-dimensional arrangement. Full Article text
ed Rubidium tetrafluoridobromate(III): redetermination of the crystal structure from single-crystal X-ray diffraction data By scripts.iucr.org Published On :: 2019-11-29 Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598]. Full Article text
ed Redetermination of the crystal structure of caesium tetrafluoridobromate(III) from single-crystal X-ray diffraction data By scripts.iucr.org Published On :: 2020-01-31 Caesium tetrafluoridobromate(III), CsBrF4, was crystallized in form of small blocks by melting and recrystallization. The crystal structure of CsBrF4 was redetermined from single-crystal X-ray diffraction data. In comparison with a previous study based on powder X-ray diffraction data [Ivlev et al. (2013). Z. Anorg. Allg. Chem. 639, 2846–2850], bond lengths and angles were determined with higher precision, and all atoms were refined with anisotropic displacement parameters. It was confirmed that the structure of CsBrF4 contains two square-planar [BrF4]− anions each with point group symmetry mmm, and a caesium cation (site symmetry mm2) that is coordinated by twelve fluorine atoms, forming an anticuboctahedron. CsBrF4 is isotypic with CsAuF4. Full Article text
ed 2,2'-[Methylenebis(sulfanediyl)]bis(pyridine 1-oxide) By scripts.iucr.org Published On :: 2020-02-11 The title compound, C11H10N2O2S2, crystallizes with one complete molecule in the asymmetric unit. In the crystal, weak hydrogen bonding is observed between the N-oxide moieties and several C—H units. Full Article text
ed Redetermination of diammonium trivanadate, (NH4)2V3O8 By scripts.iucr.org Published On :: 2020-04-09 The crystal structure of (NH4)2V3O8 has been reported twice using single-crystal X-ray data [Theobald et al. (1984). J. Phys. Chem. Solids, 45, 581–587; Range et al. (1988). Z. Naturforsch. Teil B, 43, 309–317]. In both cases, the orientation of the ammonium cation in the asymmetric unit was poorly defined: in Theobald's study, the shape and dimensions were constrained for NH4+, while in Range's study, H atoms were not included. In the present study, we collected a highly redundant data set for this ternary oxide, at 0.61 Å resolution, using Ag Kα radiation. These accurate data reveal that the NH4+ cation is disordered by rotation around a non-crystallographic axis. The rotation axis coincides with one N—H bond lying in the mirror m symmetry element of space-group type P4bm, and the remaining H sites were modelled over two disordered positions, with equal occupancy. It therefore follows that the NH4+ cations filling the space available in the (001) layered structure formed by (V3O8)2– ions do not form strong N—H⋯O hydrogen bonds with the mixed-valent oxidovanadate(IV,V) anions. This feature could have consequences for the Li-ion intercalation properties of this material, which is used as a cathode for supercapacitors. Full Article text
ed Crystal structure of pirfenidone (5-methyl-1-phenyl-1H-pyridin-2-one): an active pharmaceutical ingredient (API) By scripts.iucr.org Published On :: 2019-06-11 The crystal structure of pirfenidone, C12H11NO [alternative name: 5-methyl-1-phenylpyridin-2(1H)-one], an active pharmaceutical ingredient (API) approved in Europe and Japan for the treatment of Idiopathic pulmonary fibrosis (IPF), is reported here for the first time. It was crystallized from toluene by the temperature gradient technique, and crystallizes in the chiral monoclinic space group P21. The phenyl and pyridone rings are inclined to each other by 50.30 (11)°. In the crystal, molecules are linked by C–H⋯O hydrogen bonds involving the same acceptor atom, forming undulating layers lying parallel to the ab plane. Full Article text
ed Crystal structure of zymonic acid and a redetermination of its precursor, pyruvic acid By scripts.iucr.org Published On :: 2019-05-24 The structure of zymonic acid (systematic name: 4-hydroxy-2-methyl-5-oxo-2,5-dihydrofuran-2-carboxylic acid), C6H6O5, which had previously eluded crystallographic determination, is presented here for the first time. It forms by intramolecular condensation of parapyruvic acid, which is the product of aldol condensation of pyruvic acid. A redetermination of the crystal structure of pyruvic acid (systematic name: 2-oxopropanoic acid), C3H4O3, at low temperature (90 K) and with increased precision, is also presented [for the previous structure, see: Harata et al. (1977). Acta Cryst. B33, 210–212]. In zymonic acid, the hydroxylactone ring is close to planar (r.m.s. deviation = 0.0108 Å) and the dihedral angle between the ring and the plane formed by the bonds of the methyl and carboxylic acid carbon atoms to the ring is 88.68 (7)°. The torsion angle of the carboxylic acid group relative to the ring is 12.04 (16)°. The pyruvic acid molecule is almost planar, having a dihedral angle between the carboxylic acid and methyl-ketone groups of 3.95 (6)°. Intermolecular interactions in both crystal structures are dominated by hydrogen bonding. The common R22(8) hydrogen-bonding motif links carboxylic acid groups on adjacent molecules in both structures. In zymonic acid, this results in dimers about a crystallographic twofold of space group C2/c, which forces the carboxylic acid group to be disordered exactly 50:50, which scrambles the carbonyl and hydroxyl groups and gives an apparent equalization of the C—O bond lengths [1.2568 (16) and 1.2602 (16) Å]. The other hydrogen bonds in zymonic acid (O—H⋯O and weak C—H⋯O), link molecules across a 21-screw axis, and generate an R22(9) motif. These hydrogen-bonding interactions propagate to form extended pleated sheets in the ab plane. Stacking of these zigzag sheets along c involves only van der Waals contacts. In pyruvic acid, inversion-related molecules are linked into R22(8) dimers, with van der Waals interactions between dimers as the only other intermolecular contacts. Full Article text
ed Some chalcones derived from thiophene-3-carbaldehyde: synthesis and crystal structures By scripts.iucr.org Published On :: 2019-06-04 The synthesis, spectroscopic data and crystal and molecular structures of four 3-(3-phenylprop-1-ene-3-one-1-yl)thiophene derivatives, namely 1-(4-hydroxyphenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C13H10O2S, (1), 1-(4-methoxyphenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C14H12O2S, (2), 1-(4-ethoxyphenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C15H14O2S, (3), and 1-(4-bromophenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C13H9BrOS, (4), are described. The four chalcones have been synthesized by reaction of thiophene-3-carbaldehyde with an acetophenone derivative in an absolute ethanol solution containing potassium hydroxide, and differ in the substituent at the para position of the phenyl ring: –OH for 1, –OCH3 for 2, –OCH2CH3 for 3 and –Br for 4. The thiophene ring in 4 was found to be disordered over two orientations with occupancies 0.702 (4) and 0.298 (4). The configuration about the C=C bond is E. The thiophene and phenyl rings are inclined by 4.73 (12) for 1, 12.36 (11) for 2, 17.44 (11) for 3 and 46.1 (6) and 48.6 (6)° for 4, indicating that the –OH derivative is almost planar and the –Br derivative deviates the most from planarity. However, the substituent has no real influence on the bond distances in the α,β-unsaturated carbonyl moiety. The molecular packing of 1 features chain formation in the a-axis direction by O—H⋯O contacts. In the case of 2 and 3, the packing is characterized by dimer formation through C—H⋯O interactions. In addition, C—H⋯π(thiophene) interactions in 2 and C—H⋯S(thiophene) interactions in 3 contribute to the three-dimensional architecture. The presence of C—H⋯π(thiophene) contacts in the crystal of 4 results in chain formation in the c-axis direction. The Hirshfeld surface analysis shows that for all four derivatives, the highest contribution to surface contacts arises from contacts in which H atoms are involved. Full Article text
ed Synthesis, detailed geometric analysis and bond-valence method evaluation of the strength of π-arene bonding of two isotypic cationic prehnitene tin(II) complexes: [{1,2,3,4-(CH3)4C6H2}2Sn2Cl2][MCl4]2 (M = Al and Ga) By scripts.iucr.org Published On :: 2019-06-25 From solutions of prehnitene and the ternary halides (SnCl)[MCl4] (M = Al, Ga) in chlorobenzene, the new cationic SnII–π-arene complexes catena-poly[[chloridoaluminate(III)]-tri-μ-chlorido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetramethylbenzene)tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetramethylbenzene)tin(II)]-di-μ-chlorido-3:4κ4Cl-[chloridoaluminate(III)]-μ-chlorido-4:1'κ2Cl], [Al2Sn2Cl10(C10H14)2]n, (1) and catena-poly[[chloridogallate(III)]-tri-μ-chlorido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetramethylbenzene)tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetramethylbenzene)tin(II)]-di-μ-chlorido-3:4κ4Cl-[chloridogallate(III)]-μ-chlorido-4:1'κ2Cl], [Ga2Sn2Cl10(C10H14)2]n, (2), were isolated. In these first main-group metal–prehnitene complexes, the distorted η6 arene π-bonding to the tin atoms of the Sn2Cl22+ moieties in the centre of [{1,2,3,4-(CH3)4C6H2}2Sn2Cl2][MCl4]2 repeating units (site symmetry overline{1}) is characterized by: (i) a significant ring slippage of ca 0.4 Å indicated by the dispersion of Sn—C distances [1: 2.881 (2)–3.216 (2) Å; 2: 2.891 (3)–3.214 (3) Å]; (ii) the non-methyl-substituted arene C atoms positioned closest to the SnII central atom; (iii) a pronounced tilt of the plane of the arene ligand against the plane of the central (Sn2Cl2)2+ four-membered ring species [1: 15.59 (11)°, 2: 15.69 (9)°]; (iv) metal–arene bonding of medium strength as illustrated by application of the bond-valence method in an indirect manner, defining the π-arene bonding interaction of the SnII central atoms as s(SnII—arene) = 2 − Σs(SnII—Cl), that gives s(SnII—arene) = 0.37 and 0.38 valence units for the aluminate and the gallate, respectively, indicating that comparatively strong main-group metal–arene bonding is present and in line with the expectation that [AlCl4]− is the slightly weaker coordinating anion as compared to [GaCl4]−. Full Article text
ed Multicentered hydrogen bonding in 1-[(1-deoxy-β-d-fructopyranos-1-yl)azaniumyl]cyclopentanecarboxylate (`d-fructose-cycloleucine') By scripts.iucr.org Published On :: 2019-07-02 The title compound, C12H21NO7, (I), is conformationally unstable; the predominant form present in its solution is the β-pyranose form (74.3%), followed by the β- and α-furanoses (12.1 and 10.2%, respectively), α-pyranose (3.4%), and traces of the acyclic carbohydrate tautomer. In the crystalline state, the carbohydrate part of (I) adopts the 2C5 β-pyranose conformation, and the amino acid portion exists as a zwitterion, with the side chain cyclopentane ring assuming the E9 envelope conformation. All heteroatoms are involved in hydrogen bonding that forms a system of antiparallel infinite chains of fused R33(6) and R33(8) rings. The molecule features extensive intramolecular hydrogen bonding, which is uniquely multicentered and involves the carboxylate, ammonium and carbohydrate hydroxy groups. In contrast, the contribution of intermolecular O⋯H/H⋯O contacts to the Hirshfeld surface is relatively low (38.4%), as compared to structures of other d-fructose-amino acids. The 1H NMR data suggest a slow rotation around the C1—C2 bond in (I), indicating that the intramolecular heteroatom contacts survive in aqueous solution of the molecule as well. Full Article text
ed (E)-6,6'-(Diazene-1,2-diyl)bis(1,10-phenanthrolin-5-ol) trichloromethane disolvate: a superconjugated ligand By scripts.iucr.org Published On :: 2019-07-23 Phenanthroline ligands are important metal-binding molecules which have been extensively researched for applications in both material science and medicinal chemistry. Azobenzene and its derivatives have received significant attention because of their ability to be reversibly switched between the E and Z forms and so could have applications in optical memory and logic devices or as molecular machines. Herein we report the formation and crystal structure of a highly unusual novel diazo-diphenanthroline compound, C24H14N6O2·2CHCl3. Full Article text
ed An unexpected rhenium(IV)–rhenium(VII) salt: [Co(NH3)6]3[ReVIIO4][ReIVF6]4·6H2O By scripts.iucr.org Published On :: 2019-07-12 The title hydrated salt, tris[hexaamminecobalt(III)] tetraoxidorhenate(VII) tetrakis[hexafluoridorhenate(IV)] hexahydrate, arose unexpectedly due to possible contamination of the K2ReF6 starting material with KReO4. It consists of octahedral [Co(NH3)6]3+ cation (Co1 site symmetry 1), tetrahedral [ReVIIO4]− anions (Re site symmetry 1) and octahedral [ReIVF6]2− anions (Re site symmetries 1and overline{3}). The [ReF6]2− octahedral anions (mean Re—F = 1.834 Å), [Co(NH3)6]3+ octahedral cations (mean Co—N = 1.962 Å), and the [ReO4]− tetrahedral anion (mean Re—O = 1.719 Å) are slightly distorted. A network of N—H⋯F hydrogen bonds consolidates the structure. The crystal studied was refined as a two-component twin. Full Article text
ed Crystal structures of an imidazo[1,5-a]pyridinium-based ligand and its (C13H12N3)2[CdI4] hybrid salt By scripts.iucr.org Published On :: 2019-07-19 The monocation product of the oxidative condensation–cyclization between two molecules of pyridine-2-carbaldehyde and one molecule of CH3NH2·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium, was isolated in the presence of metal ions as bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetraiodocadmate, (C13H12N3)2[CdI4], (I), and the mixed chloride/nitrate salt, bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] 1.5-chloride 0.5-nitrate trihydrate, 2C13H12N3+·1.5Cl−·0.5NO3−·3H2O, (II). Hybrid salt (I) crystallizes in the space group P21/n with two [L]2[CdI4] molecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetrahalometallate anions are stacked parallel to the ab plane. Antiparallel L+ cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetrahedral CdI4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water molecules runs parallel to a column of stacked cations. Full Article text
ed Syntheses and structures of piperazin-1-ium ABr2 (A = Cs or Rb): hybrid solids containing `curtain wall' layers of face- and edge-sharing ABr6 trigonal prisms By scripts.iucr.org Published On :: 2019-07-26 The isostructural title compounds, poly[piperazin-1-ium [di-μ-bromido-caesium]], {(C4H11N2)[CsBr2]}n, and poly[piperazin-1-ium [di-μ-bromido-rubidium]], {(C4H11N2)[RbBr2]}n, contain singly-protonated piperazin-1-ium cations and unusual ABr6 (A = Cs or Rb) trigonal prisms. The prisms are linked into a distinctive `curtain wall' arrangement propagating in the (010) plane by face and edge sharing. In each case, a network of N—H⋯N, N—H⋯Br and N—H⋯(Br,Br) hydrogen bonds consolidates the structure. Full Article text
ed Synthesis and structure of push–pull merocyanines based on barbituric and thiobarbituric acid By scripts.iucr.org Published On :: 2019-08-16 Two compounds, 1,3-diethyl-5-{(2E,4E)-6-[(E)-1,3,3-trimethylindolin-2-ylidene]hexa-2,4-dien-1-ylidene}pyrimidine-2,4,6(1H,3H,5H)-trione or TMI, C25H29N3O3, and 1,3-diethyl-2-sulfanylidene-5-[2-(1,3,3-trimethylindolin-2-ylidene)ethylidene]dihydropyrimidine-4,6(1H,5H)-dione or DTB, C21H25N3O2S, have been crystallized and studied. These compounds contain the same indole derivative donor group and differ in their acceptor groups (in TMI it contains oxygen in the para position, and in DTB sulfur) and the length of the π-bridge. In both materials, molecules are packed in a herringbone manner with differences in the twist and fold angles. In both structures, the molecules are connected by weak C—H⋯O and/or C—H⋯S bonds. Full Article text
ed Crystal structure of a binuclear mixed-valence ytterbium complex containing a 2-anthracene-substituted phenoxide ligand By scripts.iucr.org Published On :: 2019-08-23 Reaction of 2-(anthracen-9-yl)phenol (HOPhAn, 1) with divalent Yb[N(SiMe3)2]2·2THF in THF–toluene mixtures affords the mixed-valence YbII–YbIII dimer {[2-(anthracen-9-yl)phenolato-κO]bis(tetrahydrofuran)ytterbium(III)}-tris[μ-2-(anthracen-9-yl)phenolato]-κ4O:O;κO:1,2-η,κO-{[2-(anthracen-9-yl)phenolato-κO]ytterbium(II)} toluene trisolvate, [Yb2(C20H13O)5(C4H8O)2]·3C7H7 or [YbIII(THF)2(OPhAn)](μ-OPhAn)3[YbII(OPhAn)]·3C7H7 (2), as the major product. It crystallized as a toluene trisolvate. The Yb—O bond lengths in the crystal structure of this dimer clearly identify the YbII and YbIII centres. Interestingly, the formally four-coordinate YbII centre shows a close contact with one anthracene C—C bond of a bridging OPhAn ligand, bringing the formal coordination number to five. Full Article text
ed Synthesis and redetermination of the crystal structure of salicylaldehyde N(4)-morpholinothiosemicarbazone By scripts.iucr.org Published On :: 2019-08-30 The structure of the title compound (systematic name: N-{[(2-hydroxyphenyl)methylidene]amino}morpholine-4-carbothioamide), C12H15N3O2S, was previously determined (Koo et al., 1977) using multiple-film equi-inclination Weissenberg data, but has been redetermined with higher precision to explore its conformation and the hydrogen-bonding patterns and supramolecular interactions. The molecular structure shows intramolecular O—H⋯N and C—H⋯S interactions. The configuration of the C=N bond is E. The molecule is slightly twisted about the central N—N bond. The best planes through the phenyl ring and the morpholino ring make an angle of 43.44 (17)°. In the crystal, the molecules are connected into chains by N—H⋯O and C—H⋯O hydrogen bonds, which combine to generate sheets lying parallel to (002). The most prominent contribution to the surface contacts are H⋯H contacts (51.6%), as concluded from a Hirshfeld surface analysis. Full Article text
ed Crystal structures and Hirshfeld surface analyses of (E)-N'-benzylidene-2-oxo-2H-chromene-3-carbohydrazide and the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide: lattice ene By scripts.iucr.org Published On :: 2019-09-03 The crystal structures of the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide, C20H18N2O6·0.5C2H6OS, and (E)-N'-benzylidene-2-oxo-2H-chromene-3-carbohydrazide, C17H12N2O3 (4: R = C6H5), are discussed. The non-hydrogen atoms in compound [4: R = (3,4,5-MeO)3C6H2)] exhibit a distinct curvature, while those in compound, (4: R = C6H5), are essential coplanar. In (4: R = C6H5), C—H⋯O and π–π intramolecular interactions combine to form a three-dimensional array. A three-dimensional array is also found for the hemi-DMSO solvate of [4: R = (3,4,5-MeO)3C6H2], in which the molecules of coumarin are linked by C—H⋯O and C—H⋯π interactions, and form tubes into which the DMSO molecules are cocooned. Hirshfeld surface analyses of both compounds are reported, as are the lattice energy and intermolecular interaction energy calculations of compound (4: R = C6H5). Full Article text
ed Crystal structure of (15,20-bis(2,3,4,5,6-pentafluorophenyl)-5,10-{(4-methylpyridine-3,5-diyl)bis[(sulfanediylmethylene)[1,1'-biphenyl]-4',2-diyl]}porphyrinato)nickel(II) dichloro By scripts.iucr.org Published On :: 2019-09-27 The title compound, [Ni(C64H33F10N5S2)]·xCH2Cl2, consists of discrete NiII porphyrin complexes, in which the five-coordinate NiII cations are in a distorted square-pyramidal coordination geometry. The four porphyrin nitrogen atoms are located in the basal plane of the pyramid, whereas the pyridine N atom is in the apical position. The porphyrin plane is strongly distorted and the NiII cation is located above this plane by 0.241 (3) Å and shifted in the direction of the coordinating pyridine nitrogen atom. The pyridine ring is not perpendicular to the N4 plane of the porphyrin moiety, as observed for related compounds. In the crystal, the complexes are linked via weak C—H⋯F hydrogen bonds into zigzag chains propagating in the [001] direction. Within this arrangement cavities are formed, in which highly disordered dichloromethane solvate molecules are located. No reasonable structural model could be found to describe this disorder and therefore the contribution of the solvent to the electron density was removed using the SQUEEZE option in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. Full Article text