9 'Several people' feel shaking as 4.2 magnitude earthquake strikes 190 miles from Dundee - The Courier By www.thecourier.co.uk Published On :: Wed, 25 Sep 2019 07:00:00 GMT 'Several people' feel shaking as 4.2 magnitude earthquake strikes 190 miles from Dundee The Courier Full Article
9 'Rumbling' felt during Ardnamurchan earthquake - BBC News By www.bbc.com Published On :: Tue, 17 Mar 2020 07:00:00 GMT 'Rumbling' felt during Ardnamurchan earthquake BBC News Full Article
9 Fracking: UK shale gas reserves 'significantly lower than previous estimates' - Energy Live News - Energy Made Easy By www.energylivenews.com Published On :: Wed, 21 Aug 2019 07:00:00 GMT Fracking: UK shale gas reserves 'significantly lower than previous estimates' Energy Live News - Energy Made Easy Full Article
9 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
9 Researchers Describe Why Earth's Magnetic North Pole Is Straying Away From Canada Towards Siberia - The Digital Wise By thedigitalwise.com Published On :: Sat, 09 May 2020 06:54:00 GMT Researchers Describe Why Earth's Magnetic North Pole Is Straying Away From Canada Towards Siberia The Digital Wise Full Article
9 Lockdown has cut Britain's vibrations, seismologists find - The Guardian By www.theguardian.com Published On :: Mon, 06 Apr 2020 19:15:48 GMT Lockdown has cut Britain's vibrations, seismologists find The Guardian Full Article
9 'Sonic boom' as small earthquake shakes Cornwall - ITV News By www.itv.com Published On :: Fri, 09 Aug 2019 07:00:00 GMT 'Sonic boom' as small earthquake shakes Cornwall ITV News Full Article
9 Fracking firm Cuadrilla signs secret deal with geological agency to 'destroy confidential documents' - iNews By inews.co.uk Published On :: Fri, 23 Aug 2019 21:07:09 GMT Fracking firm Cuadrilla signs secret deal with geological agency to 'destroy confidential documents' iNews Full Article
9 Riddle of 'bang' in Birmingham intensifies as British Geological Survey issue statement - Birmingham Live By www.birminghammail.co.uk Published On :: Tue, 19 Nov 2019 21:52:31 GMT Riddle of 'bang' in Birmingham intensifies as British Geological Survey issue statement Birmingham Live Full Article
9 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
9 Climate change and urbanisation 'threaten groundwater', say scientists - ENDS Report By www.endsreport.com Published On :: Mon, 20 Apr 2020 07:00:00 GMT Climate change and urbanisation 'threaten groundwater', say scientists ENDS Report Full Article
9 European lockdown a boon to seismologists checking Earth's vibrations - E&T Magazine By eandt.theiet.org Published On :: Fri, 24 Apr 2020 07:00:00 GMT European lockdown a boon to seismologists checking Earth's vibrations E&T Magazine Full Article
9 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
9 Chirality in Biological Nanospaces: Reactions in Active Sites. By Nilashis Nandi. Pp. 209. CRC Press, 2011. Price £79.99. ISBN 9781439840023. By journals.iucr.org Published On :: Full Article text
9 Polymeric poly[[decaaquabis(μ6-1,8-disulfonato-9H-carbazole-3,6-dicarboxylato)di-μ3-hydroxy-pentazinc] decahydrate] By scripts.iucr.org Published On :: 2019-05-14 The asymmetric unit of the title MOF, [Zn5(C14H5NO10S2)2(OH)2(H2O)10]n comprises three ZnII atoms, one of which is located on a centre of inversion, a tetra-negative carboxylate ligand, one μ3-hydroxide and five water molecules, each of which is coordinated. The ZnII atom, lying on a centre of inversion, is coordinated by trans sulfoxide-O atoms and four water molecules in an octahedral geometry. Another ZnII atom is coordinated by two carboxylate-O atoms, one hydroxy-O, one sulfoxide-O and a water-O atom to define a distorted trigonal–bipyramidal geometry; a close Zn⋯O(carboxylate) interaction derived from an asymmetrically coordinating ligand (Zn—O = 1.95 and 3.07 Å) suggests a 5 + 1 coordination geometry. The third ZnII atom is coordinated in an octahedral fashion by two hydroxy-O atoms, one carboxylate-O, one sulfoxide-O and two water-O atoms, the latter being mutually cis. In all, the carboxylate ligand binds six ZnII ions leading to a three-dimensional architecture. In the crystal, all acidic donors form hydrogen bonds to oxygen acceptors to contribute to the stability of the three-dimensional architecture. Full Article text
9 (2S,3S,4R,4a'R,5R,5a'R,11a'R,12'S,12a'R)-5-(Acetoxymethyl)-2',2',10',10'-tetramethyloctahydro-3H,8'H-spiro[furan-2,7'-[1,3]dioxino[4',5':5,6]pyrano[3,2-d][1,3,6]trioxocine]-3,4,12'-triyl tria By scripts.iucr.org Published On :: 2019-07-12 While the crystal structure analysis of the title compound, C26H38O15, a synthetic derivative of sucrose, was originally reported 40 years ago [Drew et al. (1979). Carbohydr. Res. 71, 35–42], the present work has allowed for the determination of its absolute configuration through the application of resonant scattering techniques. Full Article text
9 7-{3-Ethoxy-4-[2-(2-methoxyethoxy)ethoxy]phenyl}-5,6,8,9-tetrahydrodibenzo[c,h]acridine By scripts.iucr.org Published On :: 2019-09-06 In the title compound, C34H35NO4, the dihedral angle between the pyridine ring and attached benzene ring is 79.17 (8)°. The methoxyethoxy–ethoxy side chain is disordered over two orientations in a 0.732 (7):0.268 (7) ratio. In the crystal, very weak C—H⋯N and C—H⋯O interactions link the molecules. Full Article text
9 1-Isobutyl-8,9-dimethoxy-3-phenyl-5,6-dihidroimidazo[5,1-a]isoquinolin-2-ium chloride By scripts.iucr.org Published On :: 2019-10-22 The molecular salt, C23H26N2O2+·Cl−, was obtained from 1-isobutyl-8,9-dimethoxy-3-phenyl-5,6-dihydroimidazo[5,1-a]isoquinoline, which was synthesized by cyclocondensation of α-benzoylamino-γ-methyl-N-[2-(3,4-dimethoxyphenyl)ethyl]valeramide in the presence of phosphoryl chloride. The tetrahydropyridine ring adopts a twist–boat conformation. In the crystal structure, centrosymmetric dimers are formed by N—H⋯Cl and C—H⋯Cl hydrogen bonds. Full Article text
9 9α-Hydroxy-4,8-dimethyl-3'-phenyl-3,14-dioxatricyclo[9.3.0.02,4]tetradec-7-en-13-one-12-spiro-5'-isoxazole monohydrate By scripts.iucr.org Published On :: 2019-10-29 In the title compound, C22H25NO5·H2O, the ten-membered ring displays an approximate chair–chair conformation, whereas the five-membered furan ring has an envelope conformation, with the C atom of the methine group adjacent to the spiro C atom as the flap. The isoxazole ring is almost planar and its plane is slightly inclined to the plane of the attached phenyl ring. The mean plane of the furan ring is nearly perpendicular to that of the isoxazole ring, as indicated by the dihedral angle between them of 89.39 (12)°. In the crystal, the organic molecules are linked into [010] chains by O—H⋯O hydrogen bonds. The water molecule forms O—H⋯O and O—H⋯N hydrogen bonds and a weak C—H⋯O interaction is also observed. Together, these lead to a three-dimensional network. Full Article text
9 [4-(4-Methoxyphenyl)-8-oxo-3-(phenylselanyl)spiro[4.5]deca-3,6,9-trien-2-yl]methylcyanamide By scripts.iucr.org Published On :: 2020-01-28 The title compound, C25H22N2O2Se, crystallizes in the space group P21/c with one molecule in the asymmetric unit. The compound was synthesized by the addition of phenylselenyl bromide to a cyanamide. The phenylselenyl portion and the cyano group, as well as the ketone functional group in the cyclohexa-2,5-dien-1-one portion of the structure, are disordered, with occupancy factors of 0.555 (14) and 0.445 (14). Full Article text
9 [1–9-NαC]-Linusorb B3 (Cyclolinopeptide A) dimethyl sulfoxide monosolvate By scripts.iucr.org Published On :: 2020-03-13 Crystals of the dimethyl sulfoxide (DMSO) solvate of [1–9-NαC]-linusorb B3 (Cyclolinopeptide A; CLP-A; C57H84N9O9·C2H6OS), a cyclic polypeptide were obtained following peptide extraction and purification from flaxseed oil. There are four intramolecular N—H⋯O hydrogen bonds. In the crystal, the molecules are linked in chains along the a axis by N—H⋯O hydrogen bonds. Each DMSO O atom accepts a hydrogen bond from an NH group at the Phe6 location in the CLP-A molecule. Full Article text
9 (E)-6-(Furan-2-ylmethylidene)-6,7,8,9-tetrahydropyrido[2,1-b]quinazoline-11-thione By scripts.iucr.org Published On :: 2020-03-13 A quinazolinthione, C17H14N2OS, was synthesized by the condensation reaction of 6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-thione with furfural. The molecule crystallizes in the monoclinic system (Cc space group) and has an E configuration with respect to the exocyclic C=C bond. In the crystal, molecules are linked through C—H⋯π(furan) interactions, forming zigzag chains propagating along the [001] direction. Full Article text
9 Crystal structure of 7,8,15,16,17-pentathiadispiro[5.2.59.36]heptadecane By scripts.iucr.org Published On :: 2019-05-24 The title compound, C12H20S5, crystallizes in the monoclinic space group P21/c with four molecules in the unit cell. In the crystal, the asymmetric unit comprises the entire molecule with the three cyclic moieties arranged in a line. The molecules in the unit cell pack in a parallel fashion, with their longitudinal axes arranged along a uniform direction. The packing is stabilized by the one-dimensional propagation of non-classical hydrogen-bonding contacts between the central sulfur atom of the S3 fragment and the C—H of a cyclohexyl group from a glide-related molecule [C⋯S = 3.787 (2) Å]. Full Article text
9 Crystal structure of 210,220-bis(2,6-dichlorophenyl)-4,7,12,15-tetraoxa-2(5,15)-nickel(II)porpyhrina-1,3(1,2)-dibenzena-cycloheptadecaphane-9-yne dichloromethane monosolvate By scripts.iucr.org Published On :: 2019-05-31 The asymmetric unit of the title compound, [Ni(C52H34Cl4N4O4)]·CH2Cl2, consists of two discrete complexes, which show significant differences in the conformation of the side chain. Each NiII cation is coordinated by four nitrogen atoms of a porphyrin molecule within a square-planar coordination environment. Weak intramolecular C—H⋯Cl and C—H⋯O interactions stabilize the molecular conformation. In the crystal structure, discrete complexes are linked by C—H⋯Cl hydrogen-bonding interactions. In addition, the two unique dichloromethane solvate molecules (one being disordered) are hydrogen-bonded to the Cl atoms of the chlorophenyl groups of the porphyrin molecules, thus stabilizing the three-dimensional arrangement. The crystal exhibits pseudo-orthorhombic metrics, but structure refinements clearly show that the crystal system is monoclinic and that the crystal is twinned by pseudo-merohedry. Full Article text
9 Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca2RE8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2 By scripts.iucr.org Published On :: 2019-06-21 Six different rare-earth oxyapatites, including Ca2RE8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2, were synthesized using solution-based processes followed by cold pressing and sintering. The crystal structures of the synthesized oxyapatites were determined from powder X-ray diffraction (P-XRD) and their chemistries verified with electron probe microanalysis (EPMA). All the oxyapatites were isostructural within the hexagonal space group P63/m and showed similar unit-cell parameters. The isolated [SiO4]4− tetrahedra in each crystal are linked by the cations at the 4f and 6h sites occupied by RE3+ and Ca2+ in Ca2RE8(SiO4)6O2 or La3+ and Na+ in NaLa9(SiO4)6O2. The lattice parameters, cell volumes, and densities of the synthesized oxyapatites fit well to the trendlines calculated from literature values. Full Article text
9 Molecular and crystal structure of 5,9-dimethyl-5H-pyrano[3,2-c:5,6-c']bis[2,1-benzothiazin]-7(9H)-one 6,6,8,8-tetroxide dimethylformamide monosolvate By scripts.iucr.org Published On :: 2019-06-28 The title molecule crystallizes as a dimethylformamide monosolvate, C19H14N2O6S2·C3H7NO. The molecule was expected to adopt mirror symmetry but slightly different conformational characteristics of the condensed benzothiazine ring lead to point group symmetry 1. In the crystal, molecules form two types of stacking dimers with distances of 3.464 (2) Å and 3.528 (2) Å between π-systems. As a result, columns extending parallel to [100] are formed, which are connected to intermediate dimethylformamide solvent molecules by C—H⋯O interactions. Full Article text
9 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
9 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
9 Absolute structure of (3aS,5S,7aS,7bS,9aR,10R,12aR,12bS)-7b-hydroxy-4,4,7a,9a,12a-pentamethyl-10-[(2'R)-6-methylheptan-2-yl]-2,8,9-trioxooctadecahydrobenzo[d]indeno[4,5-b]azepin-5-yl acetate from 62-year-old By scripts.iucr.org Published On :: 2019-08-23 The structure of the title compound, C32H51NO6, was determined from 62-year-old crystals at room temperature and refined with 100 K data in a monoclinic (C2) space group. This compound with a triterpenoid structure, now confirmed by this study, played an important role in the determination of the structure of lanosterol. The molecules pack in linear O—H⋯O hydrogen-bonded chains along the short axis (b), while parallel chains display weak van der Waals interactions that explain the needle-shaped crystal morphology. The structure exhibits disorder of the flexible methylheptane chain at one end of the main molecule with a small void around it. Crystals of the compounds were resistant to data collection for decades with the available cameras and Mo Kα radiation single-crystal diffractometer in our laboratory until a new instrument with Cu Kα radiation operating at 100 K allowed the structure to be solved and refined. Full Article text
9 Crystal structure of 4-bromo-N-[(3,6-di-tert-butyl-9H-carbazol-1-yl)methylidene]aniline By scripts.iucr.org Published On :: 2019-09-10 In the title compound, C27H29BrN2, the carbazole ring system is essentially planar, with an r.m.s. deviation of 0.0781 (16) Å. An intramolecular N—H⋯N hydrogen bond forms an S(6) ring motif. One of the tert-butyl substituents shows rotational disorder over two sites with occupancies of 0.592 (3) and 0.408 (3). In the crystal, two molecules are associated into an inversion dimer through a pair of C—H⋯π interactions. The dimers are further linked by another pair of C—H⋯π interactions, forming a ribbon along the c-axis direction. A C—H⋯π interaction involving the minor disordered component and the carbazole ring system links the ribbons, generating a network sheet parallel to (100). Full Article text
9 The crystal structures and Hirshfeld surface analysis of 6-(naphthalen-1-yl)-6a-nitro-6,6a,6b,7,9,11a-hexahydrospiro[chromeno[3',4':3,4]pyrrolo[1,2-c]thiazole-11,11'-indeno[1,2-b]quinoxaline] and 6'-(naphthalen-1-yl)-6a By scripts.iucr.org Published On :: 2019-09-27 The title compounds, 6-(naphthalen-1-yl)-6a-nitro-6,6a,6 b,7,9,11a-hexahydrospiro[chromeno[3',4':3,4]pyrrolo[1,2-c]thiazole-11,11'-indeno[1,2-b]quinoxaline], C37H26N4O3S, (I), and 6'-(naphthalen-1-yl)-6a'-nitro-6',6a',6b',7',8',9',10',12a'-octahydro-2H-spiro[acenaphthylene-1,12'-chromeno[3,4-a]indolizin]-2-one, C36H28N2O4, (II), are new spiro derivatives, in which both the pyrrolidine rings adopt twisted conformations. In (I), the five-membered thiazole ring adopts an envelope conformation, while the eight-membered pyrrolidine-thiazole ring adopts a boat conformation. An intramolecular C—H⋯N hydrogen bond occurs, involving a C atom of the pyran ring and an N atom of the pyrazine ring. In (II), the six-membered piperidine ring adopts a chair conformation. An intramolecular C—H⋯O hydrogen bond occurs, involving a C atom of the pyrrolidine ring and the keto O atom. For both compounds, the crystal structure is stabilized by intermolecular C—H⋯O hydrogen bonds. In (I), the C—H⋯O hydrogen bonds link adjacent molecules, forming R22(16) loops propagating along the b-axis direction, while in (II) they form zigzag chains along the b-axis direction. In both compounds, C—H⋯π interactions help to consolidate the structure, but no significant π–π interactions with centroid–centroid distances of less than 4 Å are observed. Full Article text
9 Crystal structure and luminescence properties of 2-[(2',6'-dimethoxy-2,3'-bipyridin-6-yl)oxy]-9-(pyridin-2-yl)-9H-carbazole By scripts.iucr.org Published On :: 2019-10-22 In the title compound, C29H22N4O3, the carbazole system forms a dihedral angle of 68.45 (3)° with the mean plane of the bipyridine ring system. The bipyridine ring system, with two methoxy substituents, is approximately planar (r.m.s. deviation = 0.0670 Å), with a dihedral angle of 7.91 (13)° between the planes of the two pyridine rings. Intramolecular C—H⋯O/N hydrogen bonds may promote the planarity of the bipyridyl ring system. In the pyridyl-substituted carbazole fragment, the pyridine ring is tilted by 56.65 (4)° with respect to the mean plane of the carbazole system (r.m.s. deviation = 0.0191 Å). In the crystal, adjacent molecules are connected via C—H⋯O/N hydrogen bonds and C—H⋯π interactions, resulting in the formation of a three-dimensional (3D) supramolecular network. In addition, the 3D structure contains intermolecular π–π stacking interactions, with centroid–centroid distances of 3.5634 (12) Å between pyridine rings. The title compound exhibits a high energy gap (3.48 eV) and triplet energy (2.64 eV), indicating that it could be a suitable host material in organic light-emitting diode (OLED) applications. Full Article text
9 The `super acid' BF3H2O stabilized by 1,4-dioxane: new preparative aspects and the crystal structure of BF3H2O·C4H8O2 By scripts.iucr.org Published On :: 2019-10-31 Highly Brønsted-acidic boron trifluoride monohydrate, a widely used `super acid-catalyst', is a colourless fuming liquid that releases BF3 at room temperature. Compared to the liquid components, i.e. boron trifluoride monohydrate and 1,4-dioxane, their 1:1 adduct, BF3H2O·C4H8O2, is a solid with pronounced thermal stability (m.p. 401–403 K). The crystal structure of the long-time-stable easy-to-handle and weighable compound is reported along with new preparative aspects and the results of 1H, 11B, 13C and 19F spectroscopic investigations, particularly documenting its high Brønsted acidity in acetonitrile solution. The remarkable stability of solid BF3H2O·C4H8O2 is attributed to the chain structure established by O—H⋯O hydrogen bonds of exceptional strength {O2⋯H1—O1 [O⋯O = 2.534 (3) Å] and O1—H1⋯O3i [2.539 (3) Å] in the concatenating unit >O2⋯H1—O1—H2⋯O3i<}, taking into account the molecular (non-ionic) character of the structural moieties. Indirectly, this structural feature documents the outstanding acidification of the H2O molecule bound to BF3 and reflects the super acid nature of BF3H2O. In detail, the C22(7) zigzag chain system of hydrogen bonding in the title structure is characterized by the double hydrogen-bond donor and double (κO,κO') hydrogen-bond acceptor functionality of the aqua ligand and dioxane molecule, respectively, the almost equal strength of both hydrogen bonds, the approximatety linear arrangement of the dioxane O atoms and the two neighbouring water O atoms. Furthermore, the approximately planar arrangement of B, F and O atoms in sheets perpendicular to the c axis of the orthorhombic unit cell is a characteristic structural feature. Full Article text
9 Crystal and molecular structure of jatrophane diterpenoid (2R,3R,4S,5R,7S,8S,9S,13S,14S,15R)-2,3,8,9-tetraacetoxy-5,14-bis(benzoyloxy)-15-hydroxy-7-(isobutanoyloxy)jatropha-6(17),11(E)-diene By scripts.iucr.org Published On :: 2019-11-19 The structure of the jatrophane diterpenoid (ES2), C46H56O15, has orthorhombic (P212121) symmetry. The absolute configuration in the crystal has been determined as 2R,3R,4S,5R,7S,8S,9S,13S,14S,15R [the Flack parameter is −0.06 (11)]. The molecular structure features intramolecular O—H⋯O and C—H⋯O hydrogen bonding. In the crystal, C—H⋯O hydrogen bonds link the molecules into supramolecular columns parallel to the a axis. One of the acetoxy substituents is disordered over two orientations in a 0.826 (8):0.174 (8) ratio. Full Article text
9 Crystal structure and Hirshfeld surface analysis of 4-{[(anthracen-9-yl)methyl]amino}benzoic acid By scripts.iucr.org Published On :: 2020-01-01 In the molecule of the title anthracene derivative, C22H17NO2, the benzene ring is inclined to the mean plane of the anthracene ring system (r.m.s. deviation = 0.024 Å) by 75.21 (9)°. In the crystal, molecules are linked by pairs of O—H⋯O hydrogen bonds, forming classical carboxylic acid inversion dimers with an R22(8) ring motif. The dimers are linked by C—H⋯π interactions, forming a supramolecular framework. Full Article text
9 Crystal structure and Hirshfeld surface analysis of (C7H9N4O2)[ZnCl3(H2O)] By scripts.iucr.org Published On :: 2020-03-10 In the title molecular salt, 1,3-dimethyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-9-ium aquatrichloridozincate(II), (C7H9N4O2)[ZnCl3(H2O)], the fused ring system of the cation is close to planar, with the largest deviation from the mean plane being 0.037 (3) Å. In the complex anion, the ZnII cation is coordinated by three chloride ions and one oxygen atom from the water ligand in a distorted tetrahedral geometry. In the crystal, inversion dimers between pairs of cations linked by pairwise N—H⋯O hydrogen bonds generate R22(10) rings. The anions are linked into dimers by pairs of O—H⋯Cl hydrogen bonds and the respective dimers are linked by O—H⋯O and N—H⋯Cl hydrogen bonds. Together, these generate a three-dimensional supramolecular network. Hirshfeld surfaces were generated to gain further insight into the packing. Full Article text
9 Different packing motifs in the crystal structures of three molecular salts containing the 2-amino-5-carboxyanilinium cation: C7H9N2O2+·Cl−, C7H9N2O2+·Br− and C7H9N2O2+·NO3−·H2O By scripts.iucr.org Published On :: 2020-03-13 The syntheses and crystal structures of three molecular salts of protonated 3,4-diaminobenzoic acid, viz. 2-amino-5-carboxyanilinium chloride, C7H9N2O2+·Cl−, (I), 2-amino-5-carboxyanilinium bromide, C7H9N2O2+·Br−, (II), and 2-amino-5-carboxyanilinium nitrate monohydrate, C7H9N2O2+·NO3−·H2O, (III), are described. The cation is protonated at the meta-N atom (with respect to the carboxy group) in each case. In the crystal of (I), carboxylic acid inversion dimers linked by pairwise O—H⋯O hydrogen bonds are seen and each N—H group forms a hydrogen bond to a chloride ion to result in (100) undulating layers of chloride ions bridged by the inversion dimers into a three-dimensional network. The extended structure of (II) features O—H⋯Br, N—H⋯Br and N—H⋯O hydrogen bonds: the last of these generates C(7) chains of cations. Overall, the packing in (II) features undulating (100) sheets of bromide ions alternating with the organic cations. Intermolecular interactions in the crystal of (III) include O—H⋯O, O—H⋯(O,O), N—H⋯O, N—H⋯N and O—H⋯N links. The cations are linked into (001) sheets, and the nitrate ions and water molecules form undulating chains. Taken together, alternating (001) slabs of organic cations plus anions/water molecules result. Hirshfeld surfaces and fingerprint plots were generated to give further insight into the intermolecular interactions in these structures. The crystal used for the data collection of (II) was twinned by rotation about [100] in reciprocal space in a 0.4896 (15):0.5104 (15) ratio. Full Article text
9 Crystal structure, Hirshfeld surface and frontier molecular orbital analysis of 10-benzyl-9-(3-ethoxy-4-hydroxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione By scripts.iucr.org Published On :: 2020-03-27 In the fused ring system of the title compound, C32H37NO4, the central dihydropyridine ring adopts a flattened boat conformation, the mean and maximum deviations of the dihydropyridine ring being 0.1429 (2) and 0.2621 (2) Å, respectively. The two cyclohexenone rings adopt envelope conformations with the tetrasubstituted C atoms as flap atoms. The benzene and phenyl rings form dihedral angles of 85.81 (2) and 88.90 (2)°, respectively, with the mean plane of the dihydropyridine ring. In the crystal, molecules are linked via an O—H⋯O hydrogen bond, forming a helical chain along the b-axis direction. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (65.2%), O⋯H/H⋯O (18.8%) and C⋯H/H⋯C (13.9%) contacts. Quantum chemical calculations for the frontier molecular orbitals were undertake to determine the chemical reactivity of the title compound. Full Article text
9 Crystal structure and Hirshfeld surface analysis of 2-phenyl-1H-phenanthro[9,10-d]imidazol-3-ium benzoate By scripts.iucr.org Published On :: 2020-04-24 In the title compound, C21H15N2+·C7H5O2−, 2-phenyl-1H-phenanthro[9,10-d]imidazole and benzoic acid form an ion pair complex. The system is consolidated by hydrogen bonds along with π–π interactions and N—H⋯π interactions between the constituent units. For a better understanding of the crystal structure and intermolecular interactions, a Hirshfeld surface analysis was performed. Full Article text
9 Crystal structure and Hirshfeld surface analysis of 4-{[(anthracen-9-yl)methyl]amino}benzoic acid dimethylformamide monosolvate By scripts.iucr.org Published On :: 2020-04-24 The title compound, C22H17NO2·C3H7NO, was synthesized by condensation of an aromatic aldehyde with a secondary amine and subsequent reduction. It was crystallized from a dimethylformamide solution as a monosolvate, C22H17NO2·C3H7NO. The aromatic molecule is non-planar with a dihedral angle between the mean planes of the aniline moiety and the methyl anthracene moiety of 81.36 (8)°. The torsion angle of the Caryl—CH2—NH—Caryl backbone is 175.9 (2)°. The crystal structure exhibits a three-dimensional supramolecular network, resulting from hydrogen-bonding interactions between the carboxylic OH group and the solvent O atom as well as between the amine functionality and the O atom of the carboxylic group and additional C—H⋯π interactions. Hirshfeld surface analysis was performed to quantify the intermolecular interactions. Full Article text
9 The crystal structures of Fe-bearing MgCO3 sp2- and sp3-carbonates at 98 GPa from single-crystal X-ray diffraction using synchrotron radiation By scripts.iucr.org Published On :: 2020-04-21 The crystal structure of MgCO3-II has long been discussed in the literature where DFT-based model calculations predict a pressure-induced transition of the carbon atom from the sp2 to the sp3 type of bonding. We have now determined the crystal structure of iron-bearing MgCO3-II based on single-crystal X-ray diffraction measurements using synchrotron radiation. We laser-heated a synthetic (Mg0.85Fe0.15)CO3 single crystal at 2500 K and 98 GPa and observed the formation of a monoclinic phase with composition (Mg2.53Fe0.47)C3O9 in the space group C2/m that contains tetrahedrally coordinated carbon, where CO44− tetrahedra are linked by corner-sharing oxygen atoms to form three-membered C3O96− ring anions. The crystal structure of (Mg0.85Fe0.15)CO3 (magnesium iron carbonate) at 98 GPa and 300 K is reported here as well. In comparison with previous structure-prediction calculations and powder X-ray diffraction data, our structural data provide reliable information from experiments regarding atomic positions, bond lengths, and bond angles. Full Article text
9 Crystal structure of lutetium aluminate (LUAM), Lu4Al2O9 By scripts.iucr.org Published On :: 2020-04-30 The crystal structure of the title compound containing lutetium, the last element in the lanthanide series, was determined using a single crystal prepared by heating a pressed pellet of a 2:1 molar ratio mixture of Lu2O3 and Al2O3 powders in an Ar atmosphere at 2173 K for 4 h. Lu4Al2O9 is isostructural with Eu4Al2O9 and composed of Al2O7 ditetrahedra and Lu-centered six- and sevenfold oxygen polyhedra. The unit-cell volume, 787.3 (3) Å3, is the smallest among the volumes of the rare-earth (RE) aluminates, RE4Al2O9. The crystal studied was refined as a two-component pseudo-merohedric twin. Full Article text
9 Handbook of Industrial Crystallization. Third edition. Edited by Allan S. Myerson, Deniz Erdemir and Alfred Y. Lee. Cambridge University Press, 2019. Pp. 538. Price GBP 145 (hardcover). ISBN 9780521196185. By scripts.iucr.org Published On :: 2020-04-14 Full Article text
9 Isomorphism: `molecular similarity to crystal structure similarity' in multicomponent forms of analgesic drugs tolfenamic and mefenamic acid By scripts.iucr.org Published On :: 2020-01-07 The non-steroidal anti-inflammatory drugs mefenamic acid (MFA) and tolfenamic acid (TFA) have a close resemblance in their molecular scaffold, whereby a methyl group in MFA is substituted by a chloro group in TFA. The present study demonstrates the isomorphous nature of these compounds in a series of their multicomponent solids. Furthermore, the unique nature of MFA and TFA has been demonstrated while excavating their alternate solid forms in that, by varying the drug (MFA or TFA) to coformer [4-dimethylaminopyridine (DMAP)] stoichiometric ratio, both drugs have produced three different types of multicomponent crystals, viz. salt (1:1; API to coformer ratio), salt hydrate (1:1:1) and cocrystal salt (2:1). Interestingly, as anticipated from the close similarity of TFA and MFA structures, these multicomponent solids have shown an isomorphous relation. A thorough characterization and structural investigation of the new multicomponent forms of MFA and TFA revealed their similarity in terms of space group and structural packing with isomorphic nature among the pairs. Herein, the experimental results are generalized in a broader perspective for predictably identifying any possible new forms of comparable compounds by mapping their crystal structure landscapes. The utility of such an approach is evident from the identification of polymorph VI of TFA from hetero-seeding with isomorphous MFA form I from acetone–methanol (1:1) solution. That aside, a pseudopolymorph of TFA with dimethylformamide (DMF) was obtained, which also has some structural similarity to that of the solvate MFA:DMF. These new isostructural pairs are discussed in the context of solid form screening using structural landscape similarity. Full Article text
9 LAT1 (SLC7A5) and CD98hc (SLC3A2) complex dynamics revealed by single-particle cryo-EM By scripts.iucr.org Published On :: 2019-06-28 Solute carriers are a large class of transporters that play key roles in normal and disease physiology. Among the solute carriers, heteromeric amino-acid transporters (HATs) are unique in their quaternary structure. LAT1–CD98hc, a HAT, transports essential amino acids and drugs across the blood–brain barrier and into cancer cells. It is therefore an important target both biologically and therapeutically. During the course of this work, cryo-EM structures of LAT1–CD98hc in the inward-facing conformation and in either the substrate-bound or apo states were reported to 3.3–3.5 Å resolution [Yan et al. (2019), Nature (London), 568, 127–130]. Here, these structures are analyzed together with our lower resolution cryo-EM structure, and multibody 3D auto-refinement against single-particle cryo-EM data was used to characterize the dynamics of the interaction of CD98hc and LAT1. It is shown that the CD98hc ectodomain and the LAT1 extracellular surface share no substantial interface. This allows the CD98hc ectodomain to have a high degree of movement within the extracellular space. The functional implications of these aspects are discussed together with the structure determination. Full Article text
9 XTIP – the world's first beamline dedicated to the synchrotron X-ray scanning tunneling microscopy technique By scripts.iucr.org Published On :: 2020-04-14 In recent years, there have been numerous efforts worldwide to develop the synchrotron X-ray scanning tunneling microscopy (SX-STM) technique. Here, the inauguration of XTIP, the world's first beamline fully dedicated to SX-STM, is reported. The XTIP beamline is located at Sector 4 of the Advanced Photon Source at Argonne National Laboratory. It features an insertion device that can provide left- or right-circular as well as horizontal- and vertical-linear polarization. XTIP delivers monochromatic soft X-rays of between 400 and 1900 eV focused into an environmental enclosure that houses the endstation instrument. This article discusses the beamline system design and its performance. Full Article text
9 Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers By scripts.iucr.org Published On :: 2020-04-29 The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Å−1 and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure. Full Article text
9 Synchrotron X-ray diffraction investigation of the surface condition of artefacts from King Henry VIII's warship the Mary Rose By scripts.iucr.org Published On :: 2020-04-15 Synchrotron X-ray diffraction (XRD) measured on the XMaS beamline at the ESRF was used to characterize the alloy composition and crystalline surface corrosion of three copper alloy Tudor artefacts recovered from the undersea wreck of King Henry VIII's warship the Mary Rose. The XRD method adopted has a dynamic range ∼1:105 and allows reflections <0.002% of the height of major reflections in the pattern to be discerned above the background without smoothing. Laboratory XRD, scanning electron microscopy–energy dispersive spectroscopy, synchrotron X-ray fluorescence and X-ray excited optical luminescence–X-ray near-edge absorption structure were used as supporting techniques, and the combination revealed structural and compositional features of importance to both archaeology and conservation. The artefacts were brass links believed to be fragments of chainmail and were excavated from the seabed during 1981 and 1982. Their condition reflects very different treatment just after recovery, viz. complete cleaning and conservation, chemical corrosion inhibition and chloride removal only, and distilled water soaking only (to remove the chlorides). The brass composition has been determined for all three at least in the top 7 µm or so as Cu(73%)Zn(27%) from the lattice constant. Measurement of the peak widths showed significant differences in the crystallite size and microstrain between the three samples. All of the links are found to be almost chloride-free with the main corrosion products being spertiniite, sphalerite, zincite, covellite and chalcocite. The balance of corrosion products between the links reflects the conservation treatment applied to one and points to different corrosion environments for the other two. Full Article text
9 Response to Zbigniew Kaszkur's comment on the article The nanodiffraction problem By scripts.iucr.org Published On :: 2019-05-28 Full Article text
9 Bias in Science and Communication. A Field Guide. By Matthew Welsh. IOP Publishing, 2018. Pp. 177. ISBN 978-0-7503-1312-4. By journals.iucr.org Published On :: Book review Full Article text