Journal articles: 'Ribbon molecules'

1

Fun, Hoong-Kun, Ching Kheng Quah, M. Babu, and B. Kalluraya. "Ethyl 4-[3,5-bis(trifluoromethyl)phenyl]-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate." Acta Crystallographica Section E Structure Reports Online 65, no. 6 (May 29, 2009): o1404—o1405. http://dx.doi.org/10.1107/s1600536809019035.

Full text

Abstract:

In the title compound, C16H14F6N2O3, the dihydropyrimidinone ring adopts an envelope conformation. In the crystal, molecules are linked by N—H...O and C—H...O hydrogen bonds into a ribbon-like structure along thebaxis. In the ribbon, a pair of bifurcated acceptor N—H...O and C—H...O bonds generate anR21(6) ring motif. Adjacent ribbons are linkedviaC—H...F hydrogen bonds.

APA, Harvard, Vancouver, ISO, and other styles

2

Cheng, Ru-Mei, Yi-Zhi Li, Sheng-Ju Ou, and Xue-Tai Chen. "3,5-Bis(salicylideneamino)-1H-1,2,4-triazole methanol solvate." Acta Crystallographica Section E Structure Reports Online 62, no. 4 (March 15, 2006): o1424—o1425. http://dx.doi.org/10.1107/s1600536806008853.

Full text

Abstract:

In the crystal structure of the title compound, C16H13N5O2·CH4O, there are intra- and intermolecular hydrogen bonds. Molecules form dimers, which are extended to afford a ribbon structure. These ribbons are further packed, forming a three-dimensional grid structure.

APA, Harvard, Vancouver, ISO, and other styles

3

Thanigaimani, Kaliyaperumal, Packianathan Thomas Muthiah, and Daniel E. Lynch. "Hydrogen-bonding patterns in the cocrystal 2,4-diamino-6-phenyl-1,3,5-triazine–sorbic acid (1/1)." Acta Crystallographica Section E Structure Reports Online 63, no. 11 (October 26, 2007): o4450—o4451. http://dx.doi.org/10.1107/s1600536807052543.

Full text

Abstract:

In the title cocrystal, C9H9N5·C6H8O2, the asymmetric unit contains one 2,4-diamino-6-phenyl-1,3,5-triazine molecule and a sorbic acid molecule. The triazine molecules are base-paired [with a graph set of R 2 2(8)] on either side via N—H...N hydrogen bonds, forming a supramolecular ribbon along the c axis. Each triazine molecule interacts with the carboxyl group of a sorbic acid molecule via N—H...O and O—H...N hydrogen bonds, generating R 2 2(8) motifs. The supramolecular ribbons are interlinked by N—H...O hydrogen bonds involving the 2-amino group of the triazine molecules and the carboxyl O atom of the sorbic acid molecule.

APA, Harvard, Vancouver, ISO, and other styles

4

Gwak, Gyeong-Hyeon, Istvan Kocsis, Yves-Marie Legrand, Mihail Barboiu, and Jae-Min Oh. "Controlled supramolecular structure of guanosine monophosphate in the interlayer space of layered double hydroxide." Beilstein Journal of Nanotechnology 7 (December 6, 2016): 1928–35. http://dx.doi.org/10.3762/bjnano.7.184.

Full text

Abstract:

Guanosine monophosphates (GMPs) were intercalated into the interlayer space of layered double hydroxides (LDHs) and the molecular arrangement of GMP was controlled in LDHs. The intercalation conditions such as GMP/LDH molar ratio and reaction temperature were systematically adjusted. When the GMP/LDH molar ratio was 1:2, which corresponds to the charge balance between positive LDH sheets and GMP anions, GMP molecules were well-intercalated to LDH. At high temperature (100 and 80 °C), a single GMP molecule existed separately in the LDH interlayer. On the other hand, at lower temperature (20, 40 and 60 °C), GMPs tended to form ribbon-type supramolecular assemblies. Differential scanning calorimetry showed that the ribbon-type GMP assembly had an intermolecular interaction energy of ≈101 kJ/mol, which corresponds to a double hydrogen bond between guanosine molecules. Once stabilized, the interlayer GMP orientations, single molecular and ribbon phase, were successfully converted to the other phase by adjusting the external environment by stoichiometry or temperature control.

APA, Harvard, Vancouver, ISO, and other styles

5

Judai, Ken, Yoshikiyo Hatakeyama, and Junichi Nishijo. "Helical Nanostructure of Achiral Silver p-Tolylacetylide Molecules." Journal of Nanoscience 2013 (September 26, 2013): 1–3. http://dx.doi.org/10.1155/2013/545430.

Full text

Abstract:

Silver p-tolylacetylide is an achiral molecule; however, its nanostructure has been found to consist of twisted nanoribbons. The twisted ribbon is a helicoid that combines translation and perpendicular rotation along the ribbon axis. A helix, a typical chiral structure, can be created by the aggregation of achiral molecules, and the recrystallization conditions control the twist of the nanoribbons. Therefore, the recrystallization controls the chirality.

APA, Harvard, Vancouver, ISO, and other styles

6

Wu, De-Hong. "Three-dimensional hydrogen-bonded assembly in 2,2′-disulfanylidene-5,5′-biimidazolidinylidene-4,4′-dione–dimethylformamide–water (3/2/4)." Acta Crystallographica Section C Crystal Structure Communications 69, no. 12 (November 21, 2013): 1545–48. http://dx.doi.org/10.1107/s0108270113031521.

Full text

Abstract:

The title compound, 3C6H4N4O2S2·2C3H7NO·4H2O, comprises three 2,2′-disulfanylidene-5,5′-biimidazolidinylidene-4,4′-dione molecules, two dimethylformamide molecules and four water molecules arranged around a crystallographic inversion centre. The non-H atoms within the 5,5′-biimidazolidinylidene molecule are coplanar and these molecules aggregate through N—H...S hydrogen-bonding interactions with cyclic motifs [graph setR22(8)], giving two-dimensional ribbon structures which are close to being parallel. The two independent water molecules associate to form centrosymmetric cyclic hydrogen-bonded (H2O)4tetrameric units [graph setR44(8)]. The ribbon structures extend along theaaxis and are linked through the water tetramers and the dimethylformamide molecules by a combination of two- and three-centre hydrogen bonds, giving an overall three-dimensional structure.

APA, Harvard, Vancouver, ISO, and other styles

7

Strey, Mark, and Peter G. Jones. "Pyridine 1:1 adducts of urea (Z′ = 1) and thiourea (Z′ = 8)." Acta Crystallographica Section C Structural Chemistry 74, no. 4 (March 7, 2018): 406–10. http://dx.doi.org/10.1107/s2053229618002632.

Full text

Abstract:

During our studies of urea and thiourea adducts, we noticed that no adducts with unsubstituted pyridine had been structurally investigated. The 1:1 adduct of pyridine and urea, C5H5N·CH4N2O, crystallizes in the P21/c space group with Z = 4. The structure is of a standard type for urea adducts, whereby the urea molecules form a ribbon, parallel to the a axis, consisting of linked R 2 2(8) rings, and the pyridine molecules are attached to the periphery of the ribbon by bifurcated (N—H...)2N hydrogen bonds. The 1:1 adduct of pyridine and thiourea, C5H5N·CH4N2S, crystallizes in the P21/n space group, with Z = 32 (Z′ = 8). The structure displays similar ribbons to those of the urea adduct. There are two independent ribbons parallel to the b axis at z ≃ 0 and 1 \over 2, and three at z ≃ 1 \over 4 and 3 \over 4; the latter are crosslinked to form a layer structure by additional long N—H...S interactions, which each formally replace one branch of a bifurcated hydrogen-bond system.

APA, Harvard, Vancouver, ISO, and other styles

8

Sarojini, Balladka K., Hemmige S. Yathirajan, Eric C. Hosten, Richard Betz, and Christopher Glidewell. "Ethyl (4-benzyloxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate and a redetermination of ethyl (4RS)-4-(4-methoxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate, as its 0.105-hydrate, both at 200 K: subtly different hydrogen-bonded ribbons." Acta Crystallographica Section C Structural Chemistry 71, no. 1 (January 1, 2015): 59–64. http://dx.doi.org/10.1107/s2053229614026758.

Full text

Abstract:

Two sulfanylidene-1,2,3,4-tetrahydropyrimidine derivatives have been synthesized using acid-catalysed cyclocondensation reactions between thiourea, ethyl 3-oxobutanoate and substituted benzaldehydes. In each of ethyl (4RS)-4-(4-benzyloxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate, C21H22N2O3S, (I), whereZ′ = 2, and ethyl (4RS)-4-(4-methoxyphenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate 0.105-hydrate, C15H18N2O3S·0.105H2O, (II), the reduced pyrimidine ring adopts a conformation intermediate between the boat, screw-boat and twist-boat forms. In (I) and (II), a combination of N—H...O and N—H...S hydrogen bonds links the organic molecules into ribbons containing alternatingR22(8) andR44(20) rings. In (I), the ribbon contains three types of ring,viz.two differentR22(8) rings which are both centrosymmetric andR44(20) rings which are not centrosymmetric. In (II), the ribbon contains two types of ring, both of which are centrosymmetric. In compound (II), the ribbons enclose continuous channels which run along the twofold rotation axes in the space groupC2/c, and the partial-occupancy water molecules lie within these channels. Structural comparisons are made with a number of related compounds.

APA, Harvard, Vancouver, ISO, and other styles

9

Bartolucci, Gianluca, Bruno Bruni, Silvia A. Coran, and Massimo Di Vaira. "{2-Hydroxy-3-[4-(2-methoxyethyl)phenoxy]propyl}isopropylammonium hemisuccinate." Acta Crystallographica Section E Structure Reports Online 65, no. 6 (May 23, 2009): o1364—o1365. http://dx.doi.org/10.1107/s160053680901856x.

Full text

Abstract:

Metoprolol, a widely used adrenoreceptor blocking drug, is commonly administered as the succinate or tartrate salt. The structure of metoprolol succinate, C15H26NO3+·0.5C4H4O42−, is characterized by the presence of ribbons in which cations, generated byN-protonation of the metoprolol molecules, are hydrogen bonded to succinate anions. The dicarboxylic acid transfers its H atoms to two metoprolol molecules; the asymmetric unit contains one cation and half an anion, the latter possessing twofold rotational symmetry. There are localized nets of O—H...O and N—H...O hydrogen bonds along a ribbon, within centrosymmetric arrangements formed by pairs of metoprolol cations and pairs of anions, each of the latter contributing with one of its carboxyl groups to the localized net. This arrangement is repeated along the ribbon by the operation of the twofold axis bisecting the anion, as well as by the lattice translation.

APA, Harvard, Vancouver, ISO, and other styles

10

Döring, Cindy, Julian F. D. Lueck, and Peter G. Jones. "Crystal structure of the 1:2 adduct of bis(piperidinium) sulfate and 1,3-dimethylthiourea." Acta Crystallographica Section E Crystallographic Communications 73, no. 5 (April 4, 2017): 651–53. http://dx.doi.org/10.1107/s2056989017004820.

Full text

Abstract:

In the title compound, 2C5H12N+·SO42−·2C3H8N2S, the C=S groups of the two independent 1,3-dimethylurea molecules and the sulfur atom of the anion lie on twofold axes. The packing is centred on bis(piperidinium) sulfate ribbons parallel to thecaxis; the cations are hydrogen bonded to the sulfate by N—H...O and C—H...O interactions. The 1,3-dimethylurea molecules are also hydrogen bonded to sulfate O atoms, and project outwards from the ribbon parallel to thebaxis.

APA, Harvard, Vancouver, ISO, and other styles

11

Kubono, Koji, Keita Tani, Masaaki Omote, Futa Ogawa, and Taisuke Matsumoto. "Crystal Structure of (E)-2-(3,3,3-trifluoroprop-1-en-1-yl)aniline." Acta Crystallographica Section E Crystallographic Communications 74, no. 10 (September 18, 2018): 1448–50. http://dx.doi.org/10.1107/s2056989018012756.

Full text

Abstract:

The molecule of the title compound, C9H8F3N, adopts an E configuration with respect to the C=C double bond. The dihedral angle between the benzene ring and the prop-1-enyl group is 25.4 (3)°. In the crystal, molecules are linked via pairs of N—H...F hydrogen bonds into inversion dimers with an R 2 2(16) ring motif. The dimers are linked by C—H...N hydrogen bonds, forming a ribbon structure along the b-axis direction. The ribbons are linked by N—H...π and C—H...π interactions, generating a three-dimensional network.

APA, Harvard, Vancouver, ISO, and other styles

12

Karthikeyan, Ammasai, Nithianantham Jeeva Jasmine, Packianathan Thomas Muthiah, and Franc Perdih. "Supramolecular hydrogen-bonding patterns in the N(9)—H protonated and N(7)—H tautomeric form of anN6-benzoyladenine salt:N6-benzoyladeninium nitrate." Acta Crystallographica Section E Crystallographic Communications 72, no. 2 (January 9, 2016): 140–43. http://dx.doi.org/10.1107/s2056989015024871.

Full text

Abstract:

In the title molecular salt, C12H10N5O+·NO3−, the adenine unit has anN9-protonated N(7)—H tautomeric form with non-protonated N1and N3atoms. The dihedral angle between the adenine ring system and the phenyl ring is 51.10 (10)°. The typical intramolecular N7—H...O hydrogen bond with anS(7) graph-set motif is also present. The benzoyladeninium cations also form base pairs through N—H...O and C—H...N hydrogen bonds involving the Watson–Crick face of the adenine ring and the C and O atoms of the benzoyl ring of an adjacent cation, forming a supramolecular ribbon withR22(9) rings. Benzoyladeninum cations are also bridged by one of the oxygen atoms of the nitrate anion, which acts as a double acceptor, forming a pair of N—H...O hydrogen bonds to generate a second ribbon motif. These ribbons together with π–π stacking interactions between the phenyl ring and the five- and six-membered adenine rings of adjacent molecules generate a three-dimensional supramolecular architecture.

APA, Harvard, Vancouver, ISO, and other styles

13

Starosta, Wojciech, and Janusz Leciejewicz. "catena-Poly[[aqualithium(I)]-μ-3-carboxy-5,6-dimethylpyrazine-2-carboxylato-κ4O2,N1:O3,N4]." Acta Crystallographica Section E Structure Reports Online 69, no. 12 (November 13, 2013): m655—m656. http://dx.doi.org/10.1107/s1600536813030493.

Full text

Abstract:

The asymmetric unit of the title compound, [Li(C8H6N2O4)(H2O)]n, comprises three Li cations, two of which are located on a twofold rotation axis, two carboxylate anions and three water molecules, of which two are situated on the twofold rotation axis being aqua ligands. Both carboxylate anions are in μ2-bridging mode. All Li ions show a trigonal–bipyramidal coordination mode; the two located in special positions are bridged throughN,O-bonding sites generating a polymeric ribbon along thec-axis direction. The Li cation in a general position creates an independent polymeric ribbon throughN,O-bonding sites of the two symmetry-related ligands; the trigonal–bipyramidal coordination is completed by an aqua ligand. In both carboxylate anions, a carboxylate and a carboxylic acid group form an intramolecular hydrogen bond. The polymeric ribbons running along [001] are interconnected by hydrogen bonds in which the water molecules act as donors and carboxylate O atoms act as acceptors, giving rise to a three-dimensional architecture.

APA, Harvard, Vancouver, ISO, and other styles

14

Insuasty, Daniel, Rodrigo Abonía, Justo Cobo, and Christopher Glidewell. "Two closely related, and unexpected, quinolinone derivatives: a three-dimensional hydrogen-bonded framework structure and a hydrogen-bonded molecular ribbon ofR22(18) andR44(24) rings." Acta Crystallographica Section C Crystal Structure Communications 68, no. 6 (May 11, 2012): o220—o225. http://dx.doi.org/10.1107/s0108270112020860.

Full text

Abstract:

1,5-Bis(4-chlorophenyl)-3-(2-oxo-1,2-dihydroquinolin-3-yl)pentane-1,5-dione, (Ia), and 1,5-bis(2-chlorophenyl)-3-(2-oxo-1,2-dihydroquinolin-3-yl)pentane-1,5-dione, (Ib), crystallize as an 84:16 mixture, 0.84C26H19Cl2NO3·0.16C26H19Cl2NO3, in the space groupI41/a, where the molecules of the two isomers occupy very similar sites in the unit cell. A combination of one N—H...O hydrogen bond and one C—H...O hydrogen bond links the molecules, regardless of isomeric form, into a single three-dimensional framework structure. The molecules of (9RS,10RS)-8,9-bis(4-chlorobenzyl)-10-(2-oxo-1,2-dihydroquinolin-3-yl)-5,6,9,10-tetrahydrophenanthridine, C36H22Cl2N2O4, (II), are linked by two hydrogen bonds, one each of the N—H...O and C—H...O types, into a molecular ribbon in which centrosymmetric rings ofR22(18) andR44(24) types alternate. The hydrogen-bonded ribbons enclose channels, which contain highly disordered solvent molecules.

APA, Harvard, Vancouver, ISO, and other styles

15

Thoreson, Wallace B., and Cassandra L. Hays. "How ribbons make ‘sense’ for vision." Biochemist 42, no. 5 (October 6, 2020): 36–41. http://dx.doi.org/10.1042/bio20200064.

Full text

Abstract:

The processing of light by the retina and brain provides the basis for visual perception. Photons are captured and converted to electrical signals by rod and cone photoreceptor cells in the retina. These electrical signals are converted to chemical signals for transmission to downstream neurons. This article provides an overview of the mechanisms involved in transmitting light responses from rods and cones. Chemical signalling occurs at synapses between neurons. In keeping with many other neurons, the chemical messenger released by photoreceptors is the amino acid glutamate, which is packaged into small spherical vesicles. Each photoreceptor synaptic terminal has thousands of synaptic vesicles. Some of these vesicles are attached to the face of planar structures known as ribbons. Ribbons capture and deliver vesicles to release sites at the bottom of the ribbon. Upon stimulation, vesicles fuse with the cell membrane and release their contents. Glutamate molecules diffuse through the extracellular space to reach specialized receptors that regulate the activity of downstream neurons. We discuss how rates of vesicle attachment to ribbons, delivery of vesicles down the ribbon and the release of glutamate shape the information provided to downstream neurons in the visual system.

APA, Harvard, Vancouver, ISO, and other styles

16

Michelot, Audric, Stéphanie Sarda, Jean-Claude Daran, Eric Deydier, and Eric Manoury. "Crystal structure of (±)-1-({[4-(allyloxy)phenyl]sulfanyl}methyl)-2-(diphenylthiophosphoryl)ferrocene." Acta Crystallographica Section E Crystallographic Communications 71, no. 8 (July 29, 2015): 972–75. http://dx.doi.org/10.1107/s2056989015013560.

Full text

Abstract:

The title compound, [Fe(C5H5)(C27H24OPS2)], is built up from a ferrocene moiety substituted in the 1- and 2-positions by {[4-(allyloxy)phenyl]sulfanyl}methyl and diphenylthiophosphoryl groups, respectively. The two S atoms lie on opposite sides of the cyclopentadienyl ring plane to which they are attached. In the crystal, C—H...S hydrogen bonds link the molecules into a ribbon running parallel to the (-110) plane. C—H...π interactions link the ribbons to form a three-dimensional network.

APA, Harvard, Vancouver, ISO, and other styles

17

Tykarska, Ewa, and Maria Gdaniec. "Solid-state supramolecular architecture of carbenoxolone – comparative studies with glycyrrhetinic and glycyrrhizic acids." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 71, no. 1 (January 20, 2015): 25–33. http://dx.doi.org/10.1107/s2052520614026419.

Full text

Abstract:

Carbenoxolone (CBXH2), a pharmaceutically relevant derivative of glycyrrhetinic acid, was studied by X-ray crystallography. The crystal structures of its unsolvated form, propionic acid and dimethoxyethane solvates and a solvated cocrystal of the free acid with its monobasic sodium salt CBXH2·CBXHNa·(butan-2-one)2·2H2O reveal that the recurring motif of supramolecular architecture in all crystal forms is a one-dimensional ribbon with closely packed triterpene fragments. It does not result from strong specific interactions but solely from van der Waals interactions. The ribbons are further arranged into diverse layer-type aggregates with a hydrophobic interior (triterpene skeletons) and hydrophilic surfaces covered with carboxylic/carboxylate groups. Solvent molecules included at the interface between the layers influence hydrogen-bonding interactions between the carbenoxolone molecules and organization of the ribbons within the layer. Comparison of crystal structures of carbenoxolone, glycyrrhizic acid and its aglycone–glycyrrhetinic acid have shown the impact of the size and hydrophilic character of the substituent at the triterpene C3 atom on the supramolecular architecture of these three closely related molecules.

APA, Harvard, Vancouver, ISO, and other styles

18

Krukle-Berzina, Kristine, Sergey Belyakov, Anatoly Mishnev, and Kirill Shubin. "Crystal structure of a two-dimensional metal–organic framework assembled from lithium(I) and γ-cyclodextrin." Acta Crystallographica Section E Crystallographic Communications 76, no. 3 (February 14, 2020): 349–53. http://dx.doi.org/10.1107/s2056989020001942.

Full text

Abstract:

The crystal structure of the polymeric title compound, catena-poly[[[diaqualithium]-μ-γ-cyclodextrin(1−)-[aqualithium]-μ-γ-cyclodextrin(1−)] pentadecahydrate], {[Li2(C48H79O40)2(H2O)3]·15H2O} n , consists of deprotonated γ-cyclodextrin (CD) molecules assembled by lithium ions into metal–organic ribbons that are cross-linked by multiple O—H...O hydrogen bonds into sheets extending parallel to (0\overline11). Within a ribbon, one Li+ ion is coordinated by one deprotonated hydroxyl group of the first γ-CD torus and by one hydroxyl group of the second γ-CD torus as well as by two water molecules. The other Li+ ion is coordinated by one deprotonated hydroxyl and by one hydroxyl group of the second γ-CD torus, by one hydroxyl group of the first γ-CD torus as well as by one water molecule. The coordination spheres of both Li+ cations are distorted tetrahedral. The packing of the structure constitute channels along the a axis. Parts of the hydroxymethyl groups in cyclodextrin molecules as well as water molecules show two-component disorder. Electron density associated with additional disordered solvent molecules inside the cavities was removed with the SQUEEZE [Spek (2015). Acta Cryst. C71, 9–18] routine in PLATON. These solvent molecules are not considered in the given chemical formula and other crystal data. Five out of the sixteen hydroxymethyl groups and one water molecule are disordered over two sets of sites.

APA, Harvard, Vancouver, ISO, and other styles

19

Gomes, Ligia R., John Nicolson Low, Catarina Oliveira, Fernando Cagide, and Fernanda Borges. "Crystal structures of three 3,4,5-trimethoxybenzamide-based derivatives." Acta Crystallographica Section E Crystallographic Communications 72, no. 5 (April 15, 2016): 675–82. http://dx.doi.org/10.1107/s2056989016005958.

Full text

Abstract:

The crystal structures of three benzamide derivatives,viz. N-(6-hydroxyhexyl)-3,4,5-trimethoxybenzamide, C16H25NO5, (1),N-(6-anilinohexyl)-3,4,5-trimethoxybenzamide, C22H30N2O4, (2), andN-(6,6-diethoxyhexyl)-3,4,5-trimethoxybenzamide, C20H33NO6, (3), are described. These compounds differ only in the substituent at the end of the hexyl chain and the nature of these substituents determines the differences in hydrogen bonding between the molecules. In each molecule, them-methoxy substituents are virtually coplanar with the benzyl ring, while thep-methoxy substituent is almost perpendicular. The carbonyl O atom of the amide rotamer istransrelated with the amidic H atom. In each structure, the benzamide N—H donor group and O acceptor atoms link the molecules intoC(4) chains. In1, a terminal –OH group links the molecules into aC(3) chain and the combined effect of theC(4) andC(3) chains is a ribbon made up of screw relatedR22(17) rings in which the ...O—H... chain lies in the centre of the ribbon and the trimethoxybenzyl groups forms the edges. In2, the combination of the benzamideC(4) chain and the hydrogen bond formed by the terminal N—H group to an O atom of the 4-methoxy group link the molecules into a chain ofR22(17) rings. In3, the molecules are linked only byC(4) chains.

APA, Harvard, Vancouver, ISO, and other styles

20

Shripanavar, Chetan Shrimandhar, and Ray J. Butcher. "Crystal structure of (2E)-2-methoxyimino-2-{2-[(2-methylphenoxy)methyl]phenyl}-N′-(4-nitrobenzylidene)ethanohydrazide." Acta Crystallographica Section E Crystallographic Communications 71, no. 4 (March 18, 2015): 377–79. http://dx.doi.org/10.1107/s2056989015004569.

Full text

Abstract:

The title compound, C24H22N4O5, crystallizes with two molecules in the asymmetric unit (Z′ = 2) oriented almost perpendicular to each other [dihedral angle between the central core of each molecule = 77.95 (3)°]. The two molecules exhibit similar conformations with an extended structure. An intramolecular C—H...N hydrogen bond occurs in each molecule. The two molecules are linked by a bifurcated N—H...(O,N) hydrogen bond involving the NH group in moleculeAas donor. They are further linked into a ribbon along thea-axis direction by further bifurcated N—H...(O,N) hydrogen bonds involving the NH group in moleculeBas donor. C—H...O interactions are also observed.

APA, Harvard, Vancouver, ISO, and other styles

21

Luo, Fujun, Xinran Liu, Thomas C. Südhof, and Claudio Acuna. "Efficient stimulus-secretion coupling at ribbon synapses requires RIM-binding protein tethering of L-type Ca2+channels." Proceedings of the National Academy of Sciences 114, no. 38 (September 5, 2017): E8081—E8090. http://dx.doi.org/10.1073/pnas.1702991114.

Full text

Abstract:

Fast neurotransmitter release from ribbon synapses via Ca2+-triggered exocytosis requires tight coupling of L-type Ca2+channels to release-ready synaptic vesicles at the presynaptic active zone, which is localized at the base of the ribbon. Here, we used genetic, electrophysiological, and ultrastructural analyses to probe the architecture of ribbon synapses by perturbing the function of RIM-binding proteins (RBPs) as central active-zone scaffolding molecules. We found that genetic deletion of RBP1 and RBP2 did not impair synapse ultrastructure of ribbon-type synapses formed between rod bipolar cells (RBCs) and amacrine type-2 (AII) cells in the mouse retina but dramatically reduced the density of presynaptic Ca2+channels, decreased and desynchronized evoked neurotransmitter release, and rendered evoked and spontaneous neurotransmitter release sensitive to the slow Ca2+buffer EGTA. These findings suggest that RBPs tether L-type Ca2+channels to the active zones of ribbon synapses, thereby synchronizing vesicle exocytosis and promoting high-fidelity information transfer in retinal circuits.

APA, Harvard, Vancouver, ISO, and other styles

22

Frey, Guido D., Wolfgang W. Schoeller, and Eberhardt Herdtweck. "Solid-state and Calculated Electronic Structure of 4-Acetylpyrazole." Zeitschrift für Naturforschung B 69, no. 7 (July 1, 2014): 839–43. http://dx.doi.org/10.5560/znb.2014-4064.

Full text

Abstract:

The crystal structure of 1-(1H-pyrazol-4-yl)ethanone (commonly known as 4-acetylpyrazole; C5H6N2O) was determined from single-crystal X-ray data at 173 K: monoclinic, space group P21/n (no. 14), a = 3.865(1), b = 5.155(1), c = 26.105(8) Å, β = 91.13(1)°, V = 520.0(2) Å3 and Z = 4. The adjacent molecules assemble into a wave-like ribbon structure in the solid state, linked by strong intermolecular N-H...N hydrogen bonds between the pyrazole rings and a weak C-H...O=C hydrogen bond involving the carbonyl group. The ribbons are stacked in the solid state via weak π interactions between the pyrazole rings.

APA, Harvard, Vancouver, ISO, and other styles

23

Trilleras, Jorge, Juan Ramos, Justo Cobo, and Christopher Glidewell. "5,5′-Methylenebis[6-amino-3-methyl-2-methylsulfanylpyrimidin-4(3H)-one]: an unusual molecular geometry within a hydrogen-bonded molecular ribbon." Acta Crystallographica Section C Crystal Structure Communications 69, no. 9 (August 3, 2013): 1043–46. http://dx.doi.org/10.1107/s0108270113020465.

Full text

Abstract:

The molecules of the title compound, C13H18N6O2S2, lie across twofold rotation axes in the space groupC2/c. Although the pyrimidine ring is effectively planar, the bridging methylene C atom is displaced from the plane of the pyrimidine ring by 0.213 (2) Å, while the C—C—C angle at the bridging C atom is 120.3 (2)°. The molecule contains two symmetry-related N—H...O hydrogen bonds, generatingS(8) motifs, and intermoecular N—H...O hydrogen bonds link the molecules into a ribbon of edge-fused rings.

APA, Harvard, Vancouver, ISO, and other styles

24

Wu, Xiangxiang, Huahui Zeng, and Yunxia Yang. "Composite host lattices of 4,4′-sulfonyldibenzoate water/boric acid in two tetrapropylammonium inclusion compounds." Acta Crystallographica Section C Structural Chemistry 74, no. 9 (August 21, 2018): 1026–31. http://dx.doi.org/10.1107/s2053229618011580.

Full text

Abstract:

Two novel inclusion compounds of 4,4′-sulfonyldibenzoate anions and tetrapropylammonium cations with different ancillary molecules of water and boric acid, namely bis(tetrapropylammonium) 4,4′-sulfonyldibenzoate dihydrate, 2C12H28N+·C14H8O6S2−·H2O (1), and bis(tetrapropylammonium) 4,4′-sulfonyldibenzoate bis(boric acid), 2C12H28N+·C14H8O6S2−·2H3BO3 (2), were prepared and characterized using single-crystal X-ray diffraction. In the two salts, the host 4,4′-sulfonyldibenzoic acid molecules, which are converted to the corresponding anions under basic conditions, can be regarded as proton acceptors which link different proton donors of the ancillary molecules of water or boric acid. In this way, an isolated hydrogen-bonded tetramer is constructed in salt 1 and a ribbon is constructed in salt 2. The tetramers and ribbons are then packed in a repeating manner to generate various host frameworks, and the tetrapropylammonium guest counter-ions are contained in the cavities of the host lattices to give the final stable crystal structures. In these two salts, although the host anion and guest cation are the same, the difference in the ancillary small molecules results in different structures, indicating the significance of ancillary molecules in the formation of crystal structures.

APA, Harvard, Vancouver, ISO, and other styles

25

Ueji, Kan, Jaehoon Jung, Junepyo Oh, Kazuo Miyamura, and Yousoo Kim. "Thermally activated polymorphic transition from a 1D ribbon to a 2D carpet: squaric acid on Au(111)." Chem. Commun. 50, no. 76 (2014): 11230–33. http://dx.doi.org/10.1039/c4cc05794e.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Makhoul, Christian, Prajakta Gosavi, and Paul A. Gleeson. "The Golgi architecture and cell sensing." Biochemical Society Transactions 46, no. 5 (September 21, 2018): 1063–72. http://dx.doi.org/10.1042/bst20180323.

Full text

Abstract:

An array of signalling molecules are located at the Golgi apparatus, including phosphoinositides, small GTPases, kinases, and phosphatases, which are linked to multiple signalling pathways. Initially considered to be associated predominantly with membrane trafficking, signalling pathways at the Golgi are now recognised to regulate a diverse range of higher-order functions. Many of these signalling pathways are influenced by the architecture of the Golgi. In vertebrate cells, the Golgi consists of individual stacks fused together into a compact ribbon structure and the function of this ribbon structure has been enigmatic. Notably, recent advances have identified a role for the Golgi ribbon in regulation of cellular processes. Fragmentation of the Golgi ribbon results in modulation of many signalling pathways. Various diseases and disorders, including cancer and neurodegeneration, are associated with the loss of the Golgi ribbon and the appearance of a dispersed fragmented Golgi. Here, we review the emerging theme of the Golgi as a cell sensor and highlight the relationship between the morphological status of the Golgi in vertebrate cells and the modulation of signalling networks.

APA, Harvard, Vancouver, ISO, and other styles

27

Kubono, Koji, Yukiyasu Kashiwagi, Keita Tani, and Kunihiko Yokoi. "Crystal structure of (7-{[bis(pyridin-2-ylmethyl)amino-κ³ N,N′,N′′]methyl}-5-chloroquinolin-8-ol)dibromidozinc(II)." Acta Crystallographica Section E Crystallographic Communications 78, no. 3 (February 15, 2022): 326–29. http://dx.doi.org/10.1107/s2056989022001530.

Full text

Abstract:

In the title compound, [ZnBr2(C22H19ClN4O)], the ZnII atom adopts a distorted square-pyramidal coordination geometry, formed by two bromido ligands and three N atoms of the bis(pyridin-2-ylmethyl)amine moiety in the pentadentate ligand containing quinolinol. The ZnII atom is located well above the mean basal plane of the square-based pyramid. The apical position is occupied by a Br atom. The O and N atoms of the quinolinol moiety in the ligand are not coordinated to the ZnII atom. An intramolecular O—H...N hydrogen bond, generating an S(5) ring motif, stabilizes the molecular structure. In the crystal, the molecules are linked by intermolecular C—H...Br hydrogen bonds, generating ribbon structures containing alternating R 2 2(22) and R 2 2(14) rings. These ribbons are linked through an intermolecular C—H...Br hydrogen bond, forming a two-dimensional network sheet.

APA, Harvard, Vancouver, ISO, and other styles

28

Kubono, Koji, Taisuke Matsumoto, and Masatsugu Taneda. "Crystal structure of 4-bromo-N-[(3,6-di-tert-butyl-9H-carbazol-1-yl)methylidene]aniline." Acta Crystallographica Section E Crystallographic Communications 75, no. 10 (September 10, 2019): 1429–31. http://dx.doi.org/10.1107/s2056989019012374.

Full text

Abstract:

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).

APA, Harvard, Vancouver, ISO, and other styles

29

Ben Rhaiem, Tarek, Habib Boughzala, and Ahmed Driss. "Synthesis, Crystal Structure, and Comparative Study of a New Organic Material 3,4-Diaminobenzophenone Semihydrate." Journal of Chemistry 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/871395.

Full text

Abstract:

The new organic 3,4-diaminobenzophenone semihydrate (34ABPH) is grown by slow evaporation method. The compound crystallizes in the monoclinic space group: C2. The unit cell dimensions are (8) Å, (2) Å, (10) Å, andβ = 99.40 (2)° with . The crystal structure analysis reveals that the C13H12N2O molecules chains are organized into a double ribbon in the (b,c) plane. The structural components interact by N–H⋯O and O–H⋯O hydrogen bonds, building up a two-dimensional network. The presence of functional groups in the molecular structure is confirmed by the Fourier transform infrared (FT-IR) spectroscopy. Thermogravimetric analysis (TGA) confirms the presence of the water molecule.

APA, Harvard, Vancouver, ISO, and other styles

30

Döring, Cindy, Julian F. D. Lueck, and Peter G. Jones. "Structures of the adducts urea:pyrazine (1:1), thiourea:pyrazine (2:1) and thiourea:piperazine (2:1)." Zeitschrift für Naturforschung B 72, no. 6 (May 24, 2017): 441–45. http://dx.doi.org/10.1515/znb-2017-0045.

Full text

Abstract:

AbstractThe adducts urea:pyrazine (1:1) (1), thiourea:pyrazine (2:1) (2), and thiourea:piperazine (2:1) (3) were prepared and their structures determined. Adduct 1 forms a layer structure, in which urea chains of graph set C(4)[${\rm{R}}_{\rm{2}}^{\rm{1}}$(6)] run parallel to the b axis and are crosslinked by N–H···N hydrogen bonding to the pyrazine residues. Adduct 2 is a variant of the well-known ${\rm{R}}_{\rm{2}}^{\rm{2}}$(8) ribbon substructure for urea/thiourea adducts, with the pyrazine molecules attached to the remaining thiourea NH groups via bifurcated hydrogen bonds (N–H···)2S; the more distant end of the pyrazine molecules is crosslinked to another symmetry-equivalent but perpendicular ribbon system, thus creating a three-dimensional packing. The packing of adduct 3 involves thiourea layers parallel to the ab plane; the piperazine molecules occupy the regions between these layers and are linked to the thiourea molecules by two hydrogen bonds (one as donor, one as acceptor) at each piperazine nitrogen atom.

APA, Harvard, Vancouver, ISO, and other styles

31

Low, John N., Jose M. Moreno Sánchez, Paloma Arranz Mascarós, M. Luz Godino Salido, Rafael López Garzon, Justo Cobo Domingo, and Christopher Glidewell. "Hydrated metal complexes of N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)glycinate: interplay of molecular, molecular–electronic and supramolecular structures." Acta Crystallographica Section B Structural Science 57, no. 3 (May 25, 2001): 317–28. http://dx.doi.org/10.1107/s0108768100020280.

Full text

Abstract:

The title anion, (C7H8N5O4)−, L −, forms hydrated metal complexes with a range of metal ions M + and M 2+. Lithium and manganese(II) form finite molecular aggregates [Li(L)(H2O)3] (1) and [Mn(L)2(H2O)4].6H2O (4) in which the molecular aggregates are linked into three-dimensional frameworks by extensive hydrogen bonding. The sodium and potassium derivatives, [Na2(L)2(H2O)3] (2) and [K(L)(H2O)] (3) both form organic–inorganic hybrid sheets in which metal–oxygen ribbons are linked by strips containing only organic ligands: these sheets are linked by hydrogen bonds into three-dimensional frameworks. In (2) the metal–oxygen ribbon is built from pairs of edge-shared trigonal bipyramids linked by water molecules, while in (3) it consists of a continuous chain of vertex-sharing octahedra. The nitroso group in the anion acts as an η1 ligand towards Na+ and as an η2 ligand towards K+. In all cases the anion L − shows the same unusual pattern of interatomic distances as the neutral parent LH.

APA, Harvard, Vancouver, ISO, and other styles

32

Vijayan, M., K. Chinnakali, P. Amaladass, A. K. Mohanakrishnan, and Hoong-Kun Fun. "3-(4-Hexyloxyphenyl)isobenzofuran-1(3H)-one." Acta Crystallographica Section E Structure Reports Online 62, no. 5 (April 21, 2006): o1941—o1943. http://dx.doi.org/10.1107/s1600536806013298.

Full text

Abstract:

In the title compound, C20H22O3, the hexyloxyphenyl group is orthogonal to the isobenzofuran-1-one ring system. The molecules, translated by one unit cell along the a-axis direction, are linked into a chain by intermolecular C—H...O hydrogen-bonding interactions, and the inversion-related molecules of adjacent chains are linked via C—H...O hydrogen bonds to form a ribbon structure.

APA, Harvard, Vancouver, ISO, and other styles

33

Han, Jia-Jun, and Ning Li. "(Acetonitrile-κN)(3-amino-4-methylbenzenesulfonato-κN)aqua(triphenylphosphine-κP)silver(I) hemihydrate." Acta Crystallographica Section E Structure Reports Online 63, no. 11 (October 26, 2007): m2807. http://dx.doi.org/10.1107/s1600536807051549.

Full text

Abstract:

The title compound, [Ag(C7H8NO3S)(C2H3N)(C18H15P)(H2O)]·0.5H2O, has a mononuclear structure in which the AgI ion is four-coordinated by the N atoms from a 3-amino-4-methylbenzenesulfonate anion and an acetonitrile molecule, one P atom from a triphenylphosphine ligand and one O atom from a water molecule, forming a distorted tetrahedral configuration. Molecules are linked into a ribbon-like structure along the a axis by O(water)—H...O hydrogen bonds involving the coordinated water molecule, and N—H...O hydrogen bonds. The uncoordinated water molecule is disordered across an inversion centre.

APA, Harvard, Vancouver, ISO, and other styles

34

Sun, Yan-qiong, Jie Zhang, Zhan-feng Ju, and Guo-Yu Yang. "A uudd Cyclic Water Tetramer and an Opened Octameric Water Cluster in the Charge-Transfer Salts of the Bipyridinium Cation." Australian Journal of Chemistry 58, no. 8 (2005): 572. http://dx.doi.org/10.1071/ch05110.

Full text

Abstract:

Two novel charge-transfer salts, [(Bpyph)(SCN)2]·2H2O 1 and {(HBpyph)[Fe(CN)6]}·5.5H2O 2, have been synthesized and characterized using elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction studies. Compound 1 is the first bipyridinium charge-transfer salt containing a cyclic water tetramer, in which the uudd cyclic water tetramers built from four symmetry related water molecules join the Bpyph2+ cations to the dimer by hydrogen bonds between the water molecules and the nitrogen atoms of Bpyph2+. The cooperation of the hydrogen-bonding and π–π stacking interactions between the pyridyl groups results in the formation of an infinite ribbon with a herringbone arrangement. An opened water octamer has been observed in 2. It presents a new association mode of water molecules that is not predicted theoretically nor found experimentally. The water octamer is hydrogen-bonded to two HBpyph3+ cations and two [Fe(CN)6]3− anions to form water octamer-bridged HBpyPh-Fe(CN)6 dimers, which are further connected to each other via π–π offset stacking interactions to generate an infinite one-dimensional ribbon.

APA, Harvard, Vancouver, ISO, and other styles

35

Korneeva, E. V., E. V. Novikova, O. V. Loseva, A. I. Smolentsev, and A. V. Ivanov. "Binding of Gold(III) from Solutions by the [Ag6{S2CN(CH2)6}6] Cluster: Synthesis, Thermal Behavior, and Self-Organization of the Supramolecular Structure of the Double Complex [Au{S2CN(CH2)6}2]2[AgCl2]Cl·2CHCl3 (Role of Secondary Au⋅⋅⋅Cl, Ag⋅⋅⋅S, and Cl⋅⋅⋅Cl Interactions)." Russian Journal of Coordination Chemistry 47, no. 11 (November 2021): 769–79. http://dx.doi.org/10.1134/s1070328421090050.

Full text

Abstract:

Abstract The capability of silver(I) cyclo-hexamethylenedithiocarbamate to concentrate gold(III) from solutions characterized by a high level of salinity (5.15 M NaCl) into the solid phase has been established. The double chloroform-solvated Au(III)–Ag(I) complex [Au{S2CN(CH2)6}2]2[AgCl2]Cl·2CHCl3 (I) was preparatively isolated as an individual form of binding of [AuCl4]– anions. The composition of the ionic structural units of compound I indicates that gold(III) binding from a solution to the solid phase is accompanied by the complete redistribution of the HmDtc ligands between the coordination spheres of Ag(I) and Au(III). Complex I characterized by IR spectroscopy, simultaneous thermal analysis, and X-ray structure analysis (CIF file CCDC no. 2051654) exhibits the supramolecular structure containing two oppositely charged pseudo-polymeric subsystems. Complex cations [Au{S2CN(CH2)6}2]+ and anions [AgCl2]– (in a ratio of 2 : 1) form a complicatedly organized cation-anionic pseudo-polymeric ribbon ({[Au(HmDtc)2]⋅⋅⋅[AgCl2]⋅⋅⋅[Au(HmDtc)2]}+)n due to secondary interactions Ag⋅⋅⋅S (3.2613 Å) and Au⋅⋅⋅Cl (3.2765 Å). The pseudo-polymeric ribbon consists of two rows of cations and a row of anions. The outer-sphere chloride ions combine the solvate chloroform molecules by two equivalent hydrogen bonds Cl⋅⋅⋅H–C yielding anion-molecular triads [Cl3CH⋅⋅⋅Cl⋅⋅⋅HCCl3]–, which are involved in the formation of the supramolecular ribbon due to the secondary Cl⋅⋅⋅Cl interactions (3.4058 Å) between the nonequivalent chlorine atoms of the nearest solvate molecules. The study of the thermal behavior of complex I makes it possible to determine the character of thermolysis and conditions for the quantitative regeneration of bound gold.

APA, Harvard, Vancouver, ISO, and other styles

36

Yue, Zi-Long, Yu-Quan Feng, and Seik Weng Ng. "A linear heterometallic bismuth–copper coordination polymer containing two types of organic ligands." Acta Crystallographica Section C Structural Chemistry 71, no. 2 (January 12, 2015): 100–102. http://dx.doi.org/10.1107/s2053229614028125.

Full text

Abstract:

In the linear coordination polymercatena-poly[[[aqua(1,10-phenanthroline-κ2N,N′)copper(II)]-μ-pyridine-2,6-dicarboxylato-κ4O2:O2′,N,O6-[(nitrato-κ2O,O′)bismuth(III)]-μ-pyridine-2,6-dicarboxylato-κ4O2,N,O6:O6′] dihydrate], {[BiIIICuII(C7H3NO4)2(NO3)(C12H8N2)(H2O)]·2H2O}n, the BiIIIcation isO,N,O′-chelated by the two pyridine-2,6-dicarboxylate ligands andO,O′-chelated by the nitrate anion, the nine coordinating atoms conferring a tricapped trigonal prismatic environment on the metal centre. Each pyridine-2,6-dicarboxylate ligand uses one of its carboxylate O atoms to bind to an aqua(1,10-phenanthroline)copper(II) unit, the Cu—O dative bonds giving rise to the formation of a ribbon motif. The CuIIcation exhibits a square-pyramidal geometry. The ribbon motif propagates along the shortest axis of the triclinic unit cell and the solvent water molecules are hydrogen bonded to the same ribbon.

APA, Harvard, Vancouver, ISO, and other styles

37

Huang, Qiu-Ying, Chun-Li Liu, and Zi-Peng Zhou. "Two sodium(I) coordination polymers constructed by the V-shaped ligands 2,2′-[isopropylidenebis(1,4-phenyleneoxy)]diacetic acid and 2,2′-[sulfonylbis(1,4-phenyleneoxy)]diacetic acid." Acta Crystallographica Section C Crystal Structure Communications 69, no. 11 (October 9, 2013): 1322–27. http://dx.doi.org/10.1107/s0108270113026450.

Full text

Abstract:

Two new inorganic–organic coordination polymers, namely poly[[μ6-2-(4-{1-[4-(carboxymethoxy)phenyl]-1-methylethyl}phenoxy)acetato][μ4-2-(4-{1-[4-(carboxymethoxy)phenyl]-1-methylethyl}phenoxy)acetato]disodium(I)], [Na2(C19H19O6)2]n, (I), and poly[hexa-μ-aqua-diaquabis{μ3-2,2′-[sulfonylbis(1,4-phenyleneoxy)]diacetato}tetrasodium(I)], [Na4(C16H14O8)2(H2O)8]n, (II), have been prepared. In (I), the asymmetric unit contains two NaIcations and two 2-(4-{1-[4-(carboxymethoxy)phenyl]-1-methylethyl}phenoxy)acetate (HL1−) ligands. Each NaIcation is octahedrally coordinated by two ether O atoms and four carboxylate O atoms of three different HL1−ligands. The NaO6polyhedra share edges to form an inorganic ribbon along theaaxis. These inorganic ribbons are further connected by the HL1−ligands to generate two-dimensional layers parallel to the (001) plane. The structure of (II) consists of ribbons of four crystallographically independent Na atoms (three six- and one five-coordinate), which are bridged by carboxylate O atoms of 4,4′-[sulfonylbis(1,4-phenyleneoxy)]diacetate (L22−) ligands and water molecules. These ribbons are interlinked byL22−ligands through two different coordination modes to afford a three-dimensional network.

APA, Harvard, Vancouver, ISO, and other styles

38

Witko, Stephanie M., Mark Davison, Hugh W. Thompson, and Roger A. Lalancette. "3-(4-Oxocyclohexyl)propionic acid monohydrate: hydrogen bonding in the hydrate of a ζ-keto acid." Acta Crystallographica Section E Structure Reports Online 63, no. 3 (February 7, 2007): o1173—o1175. http://dx.doi.org/10.1107/s1600536807004795.

Full text

Abstract:

In the title crystal structure, C9H14O3·H2O, the water molecule accepts a hydrogen bond from the carboxyl group [O...O = 2.6004 (13) Å and O—H...O = 163°], while donating hydrogen bonds to the ketone [O...O = 2.8193 (14) Å and O—H...O = 178 (2)°] and the acid carbonyl groups [O...O = 2.8010 (14) Å and O—H...O = 174 (2)°]. This creates a network of hydrogen bonds confined within a continuous flat ribbon two molecules in width and extending in the [101] direction.

APA, Harvard, Vancouver, ISO, and other styles

39

Diop, Mouhamadou Birame, Libasse Diop, Laurent Plasseraud, and Hélène Cattey. "Crystal structure of 2-methyl-1H-imidazol-3-ium hydrogen oxalate dihydrate." Acta Crystallographica Section E Crystallographic Communications 72, no. 8 (July 12, 2016): 1113–15. http://dx.doi.org/10.1107/s2056989016011038.

Full text

Abstract:

Single crystals of the title molecular salt, C4H7N2+·HC2O4−·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N—H...(O,O) hydrogen bonds. The water molecules of crystallization link the chains into (10-1) bilayers, with the methyl groups of the cations organized in an isotactic manner.

APA, Harvard, Vancouver, ISO, and other styles

40

Hua, Tianhui, Wansheng You, Limei Daia, Yi Zhao, Yong Fang, and Xuefang Zheng. "Influence of Hydrogen Bonding Interactions on the Conformation of Ribbon-like Zn(II) Complexes Bridged by Molybdates." Zeitschrift für Naturforschung B 63, no. 11 (November 1, 2008): 1262–66. http://dx.doi.org/10.1515/znb-2008-1104.

Full text

Abstract:

Abstract The complexes [Zn(dpa)MoO4] (1) and [Zn(dpa)MoO4]·0.5H2O (20.5H2O) (dpa = 2,2'-dipyrid- ylamine) were synthesized hydrothermally. Single crystal structure analyses indicate that 1 and 2 are conformational isomers. They both consist of binuclear units of edge-sharing {ZnN2O3} trigonal bipyramids bridged by pairs of bidentate briding {MoO4}2- anions into a one-dimensional ribbon, but their orientations of the terminal O atoms of the {MoO4}2- anions are different. In 1 and 2, the ribbon-like chains are connected into a 2D network via hydrogen bonding interactions between the central N-H portions of the dpa molecules and the terminal O atoms of {MoO4} tetrahedra. For 2, in addition, the hydrogen bonding interactions between the crystal water molecules and the terminal O atoms of {MoO4} tetrahedra join the 2D layers into a 3D architecture. They play an important role not only in constructing the 3D architecture, but also in the conformational stability.

APA, Harvard, Vancouver, ISO, and other styles

41

Ouzidan, Younes, Youssef Kandri Rodi, Hafid Zouihri, El Mokhtar Essassi, and Seik Weng Ng. "5-Nitro-1-(prop-2-yn-1-yl)-2,3-dihydro-1H-1,3-benzodiazol-2-one." Acta Crystallographica Section E Structure Reports Online 68, no. 4 (March 31, 2012): o1240. http://dx.doi.org/10.1107/s1600536812013177.

Full text

Abstract:

In the two independent molecules of the title compound, C10H7N3O3, the nitro substitutent is twisted slightly with respect to the benzodiazol fused-ring system [dihedral angles = 4.9 (3) and 8.5 (1)°]. The two independent molecules are disposed about a pseudo inversion center and are held together by N—H...O hydrogen bonds. The supramolecular dimer is essentially planar [dihedral angle between the fused rings = 2.0 (1)°]. Adjacent dimers are linked by acetylene–nitro C—H...O interactions, generating a ribbon motif along (110).

APA, Harvard, Vancouver, ISO, and other styles

42

Gotoh, Kazuma, and Hiroyuki Ishida. "Crystal structures of the two isomeric hydrogen-bonded cocrystals 2-chloro-4-nitrobenzoic acid–5-nitroquinoline (1/1) and 5-chloro-2-nitrobenzoic acid–5-nitroquinoline (1/1)." Acta Crystallographica Section E Crystallographic Communications 75, no. 11 (October 22, 2019): 1694–99. http://dx.doi.org/10.1107/s2056989019013896.

Full text

Abstract:

The structures of two isomeric compounds of 5-nitroquinoline with chloro- and nitro-substituted benzoic acid, namely, 2-chloro-4-nitrobenzoic acid–5-nitroquinoline (1/1), (I), and 5-chloro-2-nitrobenzoic acid–5-nitroquinoline (1/1), (II), both C7H4ClNO4·C9H6N2O2, have been determined at 190 K. In each compound, the acid and base molecules are held together by an O—H...N hydrogen bond. In the crystal of (I), the hydrogen-bonded acid–base units are linked by a C—H...O hydrogen bond, forming a tape structure along [1\overline{2}0]. The tapes are stacked into a layer parallel to the ab plane via N—O...π interactions between the nitro group of the base molecule and the quinoline ring system. The layers are further linked by other C—H...O hydrogen bonds, forming a three-dimensional network. In the crystal of (II), the hydrogen-bonded acid–base units are linked into a wide ribbon structure running along [1\overline{1}0] via C—H...O hydrogen bonds. The ribbons are further linked via another C—H...O hydrogen bond, forming a layer parallel to (110). Weak π–π interactions [centroid–centroid distances of 3.7080 (10) and 3.7543 (9) Å] are observed between the quinoline ring systems of adjacent layers. Hirshfeld surfaces for the 5-nitroquinoline molecules of the two compounds mapped over shape index and d norm were generated to visualize the weak intermolecular interactions.

APA, Harvard, Vancouver, ISO, and other styles

43

Chan, E. J., T. R. Welberry, D. J. Goossens, A. P. Heerdegen, A. G. Beasley, and P. J. Chupas. "Single-crystal diffuse scattering studies on polymorphs of molecular crystals. I. The room-temperature polymorphs of the drug benzocaine." Acta Crystallographica Section B Structural Science 65, no. 3 (May 19, 2009): 382–92. http://dx.doi.org/10.1107/s0108768109015857.

Full text

Abstract:

The drug benzocaine (ethyl 4-aminobenzoate), commonly used as a local anaesthetic, is a bimorphic solid at room temperature. Form (I) is monoclinic P21/c, while the metastable form (II) is orthorhombic P212121. Three-dimensional diffuse X-ray scattering data have been collected for the two forms on the 11-ID-B beamline at the Advanced Photon Source (APS). Both forms show strong and highly structured diffuse scattering. The data have been interpreted and analysed using Monte Carlo (MC) modelling on the basis that the scattering is purely thermal in origin and indicates the presence of highly correlated molecular motions. In both forms (I) and (II) broad diffuse streaks are observed in the 0kl section which indicate strong longitudinal displacement correlations between molecules in the 〈031〉 directions, extending over distances of up to 50 Å. Streaks extending between Bragg peaks in the hk0 section normal to [100] correspond to correlated motions of chains of molecules extending along a that are linked by N—H...O=C hydrogen bonds and which occur together as coplanar ribbon pairs. The main difference between the two forms is in the dynamical behaviour of the ribbon pairs and in particular how they are able to slide relative to each other. While for form (I) a model involving harmonic springs is able to describe the motion satisfactorily, as simple excursions away from the average structure, there is evidence in form (II) of anharmonic effects that are precursors of a phase transition to a new low-temperature phase, form (III), that was subsequently found.

APA, Harvard, Vancouver, ISO, and other styles

44

Topnikova, Anastasiia, Elena Belokoneva, Olga Dimitrova, Anatoly Volkov, and Dina Deyneko. "Rb1.66Cs1.34Tb[Si5.43Ge0.57O15]·H2O, a New Member of the OD-Family of Natural and Synthetic Layered Silicates: Topology-Symmetry Analysis and Structure Prediction." Minerals 11, no. 4 (April 9, 2021): 395. http://dx.doi.org/10.3390/min11040395.

Full text

Abstract:

Crystals of new silicate-germanate Rb1.66Cs1.34Tb[Si5.43Ge0.57O15]·H2O have been synthesized hydrothermally in a multi-component system TbCl3:GeO2:SiO2 = 1:1:5 at T = 280 °C and P = 100 atm. K2CO3, Rb2CO3 and Cs2CO3 were added to the solution as mineralizers. The crystal structure was solved using single crystal X-ray data: a = 15.9429(3), b = 14.8407(3), c = 7.2781(1) Å, sp. gr. Pbam. New Rb,Cs,Tb-silicate-germanate consists of a [Si5.43Ge0.57O15]∞∞ corrugated tetrahedral layer combined by isolated TbO6 octahedra into the mixed microporous framework as in synthetic K3Nd[Si6O15]·2H2O, K3Nd[Si6O15] and K3Eu[Si6O15]·2H2O with the cavities occupied by Cs, Rb atoms and water molecules. Luminescence spectrum on new crystals was obtained and analysed. A comparison with the other representatives of related layered natural and synthetic silicates was carried out based on the topology-symmetry analysis by the OD (order-disorder) approach. The wollastonite chain was selected as the initial structural unit. Three symmetrical ways of forming ribbon from such a chain and three ways of further connecting ribbons to each other into the layer were revealed and described with symmetry groupoids. Hypothetical structural variants of the layers and ribbons in this family were predicted.

APA, Harvard, Vancouver, ISO, and other styles

45

Diop, Mouhamadou Birame, Libasse Diop, and Allen G. Oliver. "Crystal structure ofN-[(methylsulfanyl)carbonyl]urea." Acta Crystallographica Section E Crystallographic Communications 72, no. 3 (February 13, 2016): 325–27. http://dx.doi.org/10.1107/s2056989016002322.

Full text

Abstract:

The almost planar (r.m.s. deviation = 0.055 Å) title compound, (MeS)C(O)NHC(O)NH2, was formed during an attempted crystallization of dimethyl cyanocarbonimidodithioate with CrO2Cl2; an unexpected redox reaction converted the cyanocarbonimido moiety to a urea group and removed one methylthiol group. In the crystal, hydrogen-bonding interactions from the amide and amido N—H groups to carbonyl O atoms of neighbouring molecules result in [010] ribbon-like chains.

APA, Harvard, Vancouver, ISO, and other styles

46

Brock, Carolyn, Sean Parkin, and Václav Petříček. "An Incommensurately Modulated Small-Molecule Crystal Structure." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C172. http://dx.doi.org/10.1107/s2053273314098271.

Full text

Abstract:

The first diffraction patterns measured for crystals of 2-chloro-benzo-1,3,2-dithiarsole (C6H4S2AsCl) showed an exceptionally large triclinic cell. After routine data collection the structure could be solved without difficulty; 17 independent molecules were found. A successful conventional refinement of the 170 independent non-H atoms was possible if restraints were applied (similar bond lengths and angles for all molecules; rigid-bond restraints; three sets of 8 anisotropic displacement parameters for the S and C atoms). At convergence R, wR2 were 0.042, 0.107 for 859 variables, nearly 4K restraints and more than 24K unique reflections of which 8774 have I>2σ(I). All displacement ellipsoids were positive definite. The display program Mercury revealed that the molecules form ribbons with a core of closely spaced As and Cl atoms. Because the ribbon is obviously modulated, and because Z' = 17 is both very large and prime, the possibility of an incommensurate structure had to be considered. A new integration of the original frames using EVAL14 gave a modulation vector with components 5.012(2)/17, -3.187(2)/17, 8.016(3)/17; the modulation is clearly incommensurate in the b* direction. Refinement with JANA2006 (811 variables, 11,119 unique reflections, no restraints) gave R, wR2 values 0.045, 0.116. The overall packing is determined by the stacking of the aromatic rings and probably by the segregation of interacting As and Cl atoms. A conventional refinement of a disordered, average (Z' = 1) structure revealed two basic orientations of the C6S2 plane that must be correlated in several directions if impossibly short intermolecular contacts are to be avoided. Along the modulation vector q the orientation of the C6S2 plane varies smoothly, but q is not a direction in which the molecules are in contact. The reasons for the unusual modulation will be discussed, as will the signs that a modulated, high-Z' molecular crystal structure is actually incommensurate.

APA, Harvard, Vancouver, ISO, and other styles

47

Boopathi, Subramaniam, and Ponmalai Kolandaivel. "Study on the inter- and intra-peptide salt-bridge mechanism of Aβ23–28 oligomer interaction with small molecules: QM/MM method." Molecular BioSystems 11, no. 7 (2015): 2031–41. http://dx.doi.org/10.1039/c5mb00066a.

Full text

Abstract:

A typical QM/MM approach divides the studied system into a QM core and a MM surround. The MM-treated part of Val24–Asn27 is shown in ribbon representation, and the QM core is highlighted in ball and stick form, where Asp²³ and Lys²⁸ interact with TPT.

APA, Harvard, Vancouver, ISO, and other styles

48

Silverman, Joshua A., Logesh Mathivathanan, Evgen V. Govor, Raphael G. Raptis, and Konstantinos Kavallieratos. "Coordination polymers of CdII and PbII with croconate show remarkable differences in coordination patterns: a structural and spectroscopic study." Acta Crystallographica Section C Structural Chemistry 75, no. 7 (June 14, 2019): 935–40. http://dx.doi.org/10.1107/s2053229619007277.

Full text

Abstract:

The croconate dianion is a highly versatile ligand with two tautomeric forms making it useful for building large superstructures in the solid state. The single-crystal X-ray structures of PbII– and CdII–croconate coordination polymers, namely catena-poly[[[diaqualead(II)]-μ-croconato-κ4 O 1,O 2:O 3,O 4] monohydrate], {[Pb(C5O5)(H2O)2]·H2O} n , 1, and catena-poly[[triaquacadmium(II)]-μ-croconato-κ4 O 1,O 2:O 3,O 4], [Cd(C5O5)(H2O)3] n , 2, have been determined. Both polymers form one-dimensional (1D) structures; 1 is a nonplanar 1D zigzag coordination polymer extended along the crystallographic b axis, whereas 2 is a planar 1D ribbon parallel to the [101] direction. In 2, three H2O molecules are coordinated directly to the metal atom, while in 1, only two H2O molecules are directly coordinated to the metal atom. A third interstitial H2O molecule is involved in hydrogen bonding with O atoms of the croconate ligands of an adjacent layer and other H2O molecules, resulting in stacked double layers parallel to the [105] plane. Solid-state FT–IR and solution UV–Vis spectra also substantiate the croconate coordination.

APA, Harvard, Vancouver, ISO, and other styles

49

Li, Zong-Sheng, and Jian-She Chai. "1-(4-Aminophenyl)-2-(4-nitrophenyl)ethanone." Acta Crystallographica Section E Structure Reports Online 63, no. 3 (February 7, 2007): o1082—o1083. http://dx.doi.org/10.1107/s1600536807004369.

Full text

Abstract:

In the title compound, C14H12N2O3, the dihedral angle between the two aromatic rings is 86.13 (15)°. Intermolecular N—H...O hydrogen bonds [N...O = 2.886 (3) Å and N—H...O = 174 (3)°] between the NH2 and C=O groups link the molecules into a one-dimensional ribbon augmented by secondary N—H...O interactions [N...O = 3.105 (4) Å and N—H...O = 154 (3)°] involving NH2 and NO2 groups. Adjacent chains are linked via π–π interactions.

APA, Harvard, Vancouver, ISO, and other styles

50

Moggach, Stephen A., William G. Marshall, and Simon Parsons. "High-pressure neutron diffraction study of L-serine-I and L-serine-II, and the structure of L-serine-III at 8.1 GPa." Acta Crystallographica Section B Structural Science 62, no. 5 (September 18, 2006): 815–25. http://dx.doi.org/10.1107/s010876810601799x.

Full text

Abstract:

The hydrostatic compression of L-serine-d 7 has been studied to 8.1 GPa by neutron powder diffraction. Over the course of this pressure range the compound undergoes two phase transitions, the first between 4.6 and 5.2 GPa, yielding L-serine-II, and the second between 7.3 and 8.1 GPa, yielding L-serine-III. All three polymorphs are orthorhombic, P212121, and feature chains of serine molecules connected via head-to-tail ND...O hydrogen bonds formed between ammonium and carboxylate groups. The chains are linked into a ribbon by a second set of ND...O hydrogen bonds. The hydroxyl moieties are distributed along the outer edges of the ribbon and in phase I they connect the ribbons into a layer by chains of OD...OD hydrogen bonds. The layers are connected together by a third set of ND...O hydrogen bonds, forming R^3_4(14) rings with substantial voids at their centres. In the transition from phase I to II these voids begin to close up, but at the cost of breaking the OD...OD chains. The OD...OD hydrogen bonds are replaced by shorter OD...O hydrogen bonds to carboxylate groups. At 7.3 GPa the O...O distance in the OD...O hydrogen bonds measures only 2.516 (17) Å, which is short, and we propose that the phase transition to phase III that occurs between 7.3 and 8.1 GPa relieves the strain that has built up in this region of the structure. The hydroxyl D atom now bifurcates between the OD...O contact that had been present in phase II and a new OD...O contact formed to a carboxylate in another layer. Hirshfeld surface fingerprint plots show that D...D interactions become more numerous, while hydrogen bonds actually begin to lengthen in the transition from phase II to III.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Ribbon molecules'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles