Home About us Contact
|
Home About us Contact | ||
|
|
||
Two-dimensional Network (two-dimensional + network)
Selected AbstractsTwo-dimensional networks in 2-methylanilinium picrate and 2,5-dichloroanilinium picrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010Gao-Xiang Meng Both the title molecular adducts of 2-methylaniline or 2,5-dichloroaniline with picric acid are 1:1 organic salts, namely 2-methylanilinium picrate, C7H10N+·C6H2N3O7,, (I), and 2,5-dichloroanilinium picrate, C6H6Cl2N+·C6H2N3O7,, (II). In both structures, the phenoxide O atoms accept two N,H hydrogen bonds in a bifurcated acceptor fashion, which link the component ions by N,H...O hydrogen bonds into continuous two-dimensional zigzag layers, running parallel to the (100) plane in (I) and the (010) plane in (II). A ,,, interaction is observed between symmetry-related anilinium cations in (I), while in (II), Cl...Onitro and Cl...Cl interactions are observed. This study indicates that a substitution on aniline can exert a pivotal influence on the construction of its supramolecular structure. [source] First Examples of Ternary Lanthanide 2,2,-Diphenyldicarboxylate Complexes: Hydrothermal Syntheses and Structures of Lanthanide Coordination Polymers of 2,2,-Diphenyldicarboxylic Acid and 1,10-PhenanthrolineEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2003Yibo Wang Abstract In the four new lanthanide coordination polymers {[La2(2,2,-dpdc)3(phen)(H2O)]·2H2O}n (1), [Eu2(2,2,-dpdc)3(phen)(H2O)2]n (2), {[Ln2(2,2,-dpdc)3(phen)2(H2O)2]·4H2O}n [Ln = Tb (3), Yb (4)] (2,2,-dpdc = 2,2,-diphenyldicarboxylate, phen = 1,10-phenanthroline), prepared by hydrothermal synthesis, the 2,2,-dpdc dianion affords tetradentate, pentadentate, and hexadentate coordination modes. Complex 1 is a two-dimensional network of infinite 1-D chains assembled through ,,, interactions, with nine- and ten-coordinate La3+, and arranged in wave-like layers. In 2, Eu3+ possesses nine- and ten-coordinate geometries bridged by 2,2,-dpdc ligands to give a 3-D structure. The isomorphous complexes 3 and 4, in which Tb3+ and Yb3+ ions are both nine-coordinate, have two-dimensional structures of 1-D zigzag chains stacked via hydrogen bonds and ,,, interactions of phen molecules. The high-resolution emission spectrum of 2 shows two Eu3+ ion sites, which is consistent with the results of the X-ray crystal structure analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Effect of Small-World Networks on Epidemic Propagation and InterventionGEOGRAPHICAL ANALYSIS, Issue 3 2009Zengwang Xu The small-world network, characterized by special structural properties of high connectivity and clustering, is one of the highlights in recent advances in network science and has the potential to model a variety of social contact networks. In an attempt to better understand how these structural properties of small-world networks affect epidemic propagation and intervention, this article uses an agent-based approach to investigate the interplay between an epidemic process and its underlying network structure. Small-world networks are derived from a network "rewiring" process, which readjusts edges in a completely regular two-dimensional network by different rewiring probabilities (0,1) to produce a spectrum of modified networks on which an agent-based simulation of epidemic propagation can be conducted. A comparison of simulated epidemics discloses the effect of small-world networks on epidemic propagation as well as the effectiveness of different intervention strategies, including mass vaccination, acquaintance vaccination, targeted vaccination, and contact tracing. Epidemics taking place on small-world networks tend to reach large-scale epidemic peaks within a short time period. Among the four intervention strategies tested, only one strategy,the targeted vaccination,proves to be effective for containing epidemics, a finding supported by a simulation of the severe acute respiratory syndrome epidemic in a large-scale realistic social contact network in Portland, OR. Las redes de mundo de pequeño (,small-world networks'), caracterizadas por sus propiedades estructurales especiales de alta conectividad y aglomeración (,clustering') son uno de los ejemplos más destacados de los avances más recientes de la ciencia de redes, y tiene el potencial de modelar una gran variedad de redes sociales de contacto. En un intento de comprender mejor como estas propiedades estructurales de redes ,small-world' afectan la propagación e intervención de epidemias, el estudio presente emplea un enfoque basado en modelos multi-agente (,agent based') para investigar la interacción entre el proceso epidémico y la estructura de redes en la que estan integrados. Las redes de mundo pequeño se derivan del proceso de recableado (,rewiring') el cual reajusta los límites en una red 2-D de acuerdo a varias probabilidades de reconexión (0-1) para producir un abanico de posibles de redes modificadas sobre los cuales se condujo una simulación multi-agente de la propagación de la epidemia. El efecto de las redes ,small world' y de las diferentes estrategias de intervención (por ejemplo, diferentes estrategias de vacunación) son evidenciadas mediante la comparación entre varias simulaciones de la epidemia. Las epidemias que ocurren en redes de tipo ,small-world' tienden a alcanzar picos de gran escala epidémica en un corto periodo de tiempo. Entre las estrategias evaluadas, sólo una ,vacunación dirigida a una población objetivo (,targeted vaccination')- demostró ser efectiva en la contención de la epidemia. Dicho resultado se obtuvo vía la simulación de la epidemia de SRAS (Síndrome Respiratorio Agudo Severo ,SARS') realiada en Portland, Oregon (EEUU). [source] Misfit dislocations and surface morphology of InGaAs/GaAs heterostructures grown by MOVPEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2009ukasz Gelczuk Abstract A two-dimensional network of misfit dislocations at the interface of the partially relaxed Inx Ga1- xAs epitaxial layers grown on (001)-oriented GaAs substrates by metalorganic vapor-phase epitaxy (MOVPE) has been revealed by transmission electron microscopy (TEM). A close correspondence between the distribution of interfacial misfit dislocations and undulating surface morphology in the form of a characteristic cross-hatch pattern has been observed by means of atomic force microcopy (AFM). Anisotropic strain relaxation attributed to the asymmetry in the formation of misfit dislocations has been also reproduced on the surface in the form of a fine pattern, cutting the cross-hatch one. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Polymorphism in the nitrate salt of the [Mn(acetylacetonate)2(H2O)2]+ ionACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2010A. R. Biju The crystallization of [Mn(acac)2(H2O)2]+ from solutions containing excess nitrate leads to the formation of four polymorphs. All polymorphs contain two different types of complex ions, one containing essentially coplanar acac ligands and the other in which the two acac ligands together assume a chair conformation. Molecular modelling using DFT (density-functional theory) calculations shows that the coplanar conformation is the electronically stable one. The hydrogen bonding between the trans -water molecules and the nitrate ion produces a one-dimensional chain of 12-membered rings, which are further organized into a two-dimensional network via a lattice water molecule. Lattice-energy calculations have been carried out to compare the stabilities of the four polymorphs. [source] Ferrocene compounds: methyl 1,-aminoferrocene-1-carboxylateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010Christoph Förster The title compund, [Fe(C5H6N)(C7H7O2)], features one strong intermolecular hydrogen bond of the type N,H...O=C [N...O = 3.028,(2),Å] between the amine group and the carbonyl group of a neighbouring molecule, and vice versa, to form a centrosymmetric dimer. Furthermore, the carbonyl group acts as a double H-atom acceptor in the formation of a second, weaker, hydrogen bond of the type C,H...O=C [C...O = 3.283,(2),Å] with the methyl group of the ester group of a second neighbouring molecule at (x, ,y , , z , ). The methyl group also acts as a weak hydrogen-bond donor, symmetry-related to the latter described C,H...O=C interaction, to a third molecule at (x, ,y , , z + ) to form a two-dimensional network. The cyclopentadienyl rings of the ferrocene unit are parallel to each other within 0.33,(3)° and show an almost eclipsed 1,1,-conformation, with a relative twist angle of 9.32,(12)°. The ester group is twisted slightly [11.33,(8)°] relative to the cylopentadienyl plane due to the above-mentioned intermolecular hydrogen bonds of the carbonyl group. The N atom shows pyramidal coordination geometry, with the sum of the X,N,Y angles being 340,(3)°. [source] N,N,-Diethyl-4-nitrobenzene-1,3-diamine, 2,6-bis(ethylamino)-3-nitrobenzonitrile and bis(4-ethylamino-3-nitrophenyl) sulfoneACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010Thomas J. Payne N,N,-Diethyl-4-nitrobenzene-1,3-diamine, C10H15N3O2, (I), crystallizes with two independent molecules in the asymmetric unit, both of which are nearly planar. The molecules differ in the conformation of the ethylamine group trans to the nitro group. Both molecules contain intramolecular N,H...O hydrogen bonds between the adjacent amine and nitro groups and are linked into one-dimensional chains by intermolecular N,H...O hydrogen bonds. The chains are organized in layers parallel to (101) with separations of ca 3.4,Å between adjacent sheets. The packing is quite different from what was observed in isomeric 1,3-bis(ethylamino)-2-nitrobenzene. 2,6-Bis(ethylamino)-3-nitrobenzonitrile, C11H14N4O2, (II), differs from (I) only in the presence of the nitrile functionality between the two ethylamine groups. Compound (II) crystallizes with one unique molecule in the asymmetric unit. In contrast with (I), one of the ethylamine groups, which is disordered over two sites with occupancies of 0.75 and 0.25, is positioned so that the methyl group is directed out of the plane of the ring by approximately 85°. This ethylamine group forms an intramolecular N,H...O hydrogen bond with the adjacent nitro group. The packing in (II) is very different from that in (I). Molecules of (II) are linked by both intermolecular amine,nitro N,H...O and amine,nitrile N,H...N hydrogen bonds into a two-dimensional network in the (10) plane. Alternating molecules are approximately orthogonal to one another, indicating that ,,, interactions are not a significant factor in the packing. Bis(4-ethylamino-3-nitrophenyl) sulfone, C16H18N4O6S, (III), contains the same ortho nitro/ethylamine pairing as in (I), with the position para to the nitro group occupied by the sulfone instead of a second ethylamine group. Each 4-ethylamino-3-nitrobenzene moiety is nearly planar and contains the typical intramolecular N,H...O hydrogen bond. Due to the tetrahedral geometry about the S atom, the molecules of (III) adopt an overall V shape. There are no intermolecular amine,nitro hydrogen bonds. Rather, each amine H atom has a long (H...O ca 2.8,Å) interaction with one of the sulfone O atoms. Molecules of (III) are thus linked by amine,sulfone N,H...O hydrogen bonds into zigzag double chains running along [001]. Taken together, these structures demonstrate that small changes in the functionalization of ethylamine,nitroarenes cause significant differences in the intermolecular interactions and packing. [source] Tetrakis(,2 -4-aminobenzoato)di-,3 -oxido-tetrakis[dibutyltin(IV)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010Anthony Linden The molecule of the title compound, [Sn4(C4H9)8(C7H6NO2)4O2], lies about an inversion centre and is a tetranuclear bis(tetrabutyldicarboxylatodistannoxane) complex containing a planar Sn4O2 core in which two ,3 -oxide O atoms connect an Sn2O2 ring to two exocyclic Sn atoms. Each Sn atom has a highly distorted octahedral coordination. In the molecule, the carboxylate groups of two aminobenzoate ligands bridge the central and exocyclic Sn atoms, while two further aminobenzoate ligands have highly asymmetric bidentate chelation to the exocyclic Sn atoms plus long O...Sn interactions with the central Sn atoms. Each Sn atom is also coordinated by two pendant n -butyl ligands, which extend roughly perpendicular to the plane of the Sn4O10 core. Only one of the four unique hydrogen-bond donor sites is involved in a classic N,H...O hydrogen bond, and the resulting supramolecular hydrogen-bonded structure is an extended two-dimensional network which lies parallel to the (100) plane and consists of a checkerboard pattern of four-connected molecular cores acting as nodes. The amine groups not involved in the hydrogen-bonding interactions have significant N,H..., interactions with neighbouring aminobenzene rings. [source] Two two-dimensional hydrogen-bonded coordination networks: bis(3-carboxybenzoato-,O)bis(4-methyl-1H -imidazole-,N3)copper(II) and bis(3-methylbenzoato-,N)bis(4-methyl-1H -imidazole-,N3)copper(II) monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Ziliang Wang The title two-dimensional hydrogen-bonded coordination compounds, [Cu(C8H5O4)2(C4H6N2)2], (I), and [Cu(C8H7O2)2(C4H6N2)2]·H2O, (II), have been synthesized and structurally characterized. The molecule of complex (I) lies across an inversion centre, and the Cu2+ ion is coordinated by two N atoms from two 4-methyl-1H -imidazole (4-MeIM) molecules and two O atoms from two 3-carboxybenzoate (HBDC,) anions in a square-planar geometry. Adjacent molecules are linked through intermolecular N,H...O and O,H...O hydrogen bonds into a two-dimensional sheet with (4,4) topology. In the asymmetric part of the unit cell of (II) there are two symmetry-independent molecules, in which each Cu2+ ion is also coordinated by two N atoms from two 4-MeIM molecules and two O atoms from two 3-methylbenzoate (3-MeBC,) anions in a square-planar coordination. Two neutral complex molecules are held together via N,H...O(carboxylate) hydrogen bonds to generate a dimeric pair, which is further linked via discrete water molecules into a two-dimensional network with the Schläfli symbol (43)2(46,66,83). In both compounds, as well as the strong intermolecular hydrogen bonds, ,,, interactions also stabilize the crystal stacking. [source] Three-dimensional networks in bis(imidazolium) 2,2,-dithiodibenzoate and 4-methylimidazolium 2-[(2-carboxyphenyl)disulfanyl]benzoateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Linheng Wei Cocrystallization of imidazole or 4-methylimidazole with 2,2,-dithiodibenzoic acid from methanol solution yields the title 2:1 and 1:1 organic salts, 2C3H5N2+·C14H10O4S22,, (I), and C4H7N2+·C14H10O4S2,, (II), respectively. Compound (I) crystallizes in the monoclinic C2/c space group with the mid-point of the S,S bond lying on a twofold axis. The component ions in (I) are linked by intermolecular N,H...O hydrogen bonds to form a two-dimensional network, which is further linked by C,H...O hydrogen bonds into a three-dimensional network. In contrast, by means of N,H...O, N,H...S and O,H...O hydrogen bonds, the component ions in (II) are linked into a tape and adjacent tapes are further linked by ,,,, C,H...O and C,H..., interactions, resulting in a three-dimensional network. [source] N,H...O and O,H...O hydrogen-bonded supramolecular networks in 4-chloroanilinium, 2-hydroxyanilinium and 3-hydroxyanilinium hydrogen phthalatesACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009R. Jagan The title salts, 4-chloroanilinium hydrogen phthalate (PCAHP), C6H7ClN+·C8H5O4,, 2-hydroxyanilinium hydrogen phthalate (2HAHP), C6H8NO+·C8H5O4,, and 3-hydroxyanilinium hydrogen phthalate (3HAHP), C6H8NO+·C8H5O4,, all crystallize in the space group P21/c. The asymmetric unit of 2HAHP contains two independent ion pairs. The hydrogen phthalate ions of 2HAHP and 3HAHP show a short intramolecular O,H...O hydrogen bond, with O...O distances ranging from 2.3832,(15) to 2.3860,(14),Å. N,H...O and O,H...O hydrogen bonds, together with short C,H...O contacts in PCAHP and 3HAHP, generate extended hydrogen-bond networks. PCAHP forms a two-dimensional supramolecular sheet extending in the (100) plane, whereas 2HAHP has a supramolecular chain running parallel to the [100] direction and 3HAHP has a two-dimensional network extending parallel to the (001) plane. [source] 4-Aminopyridinium 4-aminobenzoate dihydrate and 4-aminopyridinium nicotinateACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Samuel Robinson Jebas In the title compounds, 4-aminopyridinium 4-aminobenzoate dihydrate, C7H6NO2,·C5H7N2+·2H2O, (I), and 4-aminopyridinium nicotinate, C5H7N2+·C6H4NO2,, (II), the aromatic N atoms of the 4-aminopyridinium cations are protonated. In (I), the asymmetric unit is composed of two 4-aminopyridinium cations, two 4-aminobenzoate anions and four water molecules, and the compound crystallizes in a noncentrosymmetric space group. The two sets of independent molecules of (I) are related by a centre of symmetry which is not part of the space group. In (I), the protonated pyridinium ring H atoms are involved in bifurcated hydrogen bonding with carboxylate O atoms to form an R12(4) ring motif. The water molecules link the ions to form a two-dimensional network along the (10) plane. In (II), an intramolecular bifurcated hydrogen bond generates an R12(4) ring motif and inter-ion hydrogen bonding generates an R42(16) ring motif. The packing of adduct (II) is consolidated via N,H...O and N,H...N hydrogen bonds to form a two-dimensional network along the (10) plane. [source] catena -Poly[[[tetraaquazinc(II)]-,-4-amino-3,5-di-3-pyridyl-4H -1,2,4-triazole] sulfate monohydrate] and poly[[bis(,-4-amino-3,5-di-4-pyridyl-4H -1,2,4-triazole)diaquacopper(II)] dinitrate octahydrate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2009Hai-Ying Wang The isomeric bent triazole-containing ligands 4-amino-3,5-di-3-pyridyl-4H -1,2,4-triazole (L1) and 4-amino-3,5-di-4-pyridyl-4H -1,2,4-triazole (L2) have been used to create the two novel title complexes catena -poly[[[tetraaquazinc(II)]-,-4-amino-3,5-di-3-pyridyl-4H -1,2,4-triazole] sulfate monohydrate], {[Zn(C12H10N6)(H2O)4]SO4·H2O}n, (I), and poly[[diaquabis(,-4-amino-3,5-di-4-pyridyl-4H -1,2,4-triazole)copper(II)] dinitrate octahydrate], {[Cu(C12H10N6)2(H2O)2](NO3)2·8H2O}n, (II). The ZnII and CuII atoms are all six-coordinated in approximately octahedral environments. Compound (I) presents a sinusoidal chain generated by ZnO4 cores which are bridged by L1 ligands in a cisoid conformation. These sinusoidal chains are bound to each other by O,H...O hydrogen bonds between coordinated water molecules of neighboring chains into a two-dimensional network. These layers stack in an ,ABAB, sequence and are further linked into a three-dimensional framework through O,H...N hydrogen bonds between coordinated water molecules and the N atoms of the triazole rings. In (II), the CuII centers are bridged by the L2 ligands to form a two-dimensional network with square grids. All of the two-dimensional nets also stack alternately along the crystallographic a axis. Neighboring layers are further linked into a three-dimensional framework via interlayer N,H...N hydrogen bonds between ,NH2 groups of the triazole rings and the N atoms in the triazole rings. [source] Nickel and zinc complexes with a monodentate heterocycle and tridentate Schiff base ligands: self-assembly to one- and two-dimensional supramolecular networks via hydrogen bondingACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Xiao-Hua Chen In the complex (morpholine)[2-hydroxy- N,-(5-nitro-2-oxidobenzylidene)benzohydrazidato]nickel(II), [Ni(C14H9N3O5)(C4H9NO)], (I), the NiII center is in a square-planar N2O2 coordination geometry. The complex bis[,-2-hydroxy- N,-(2-oxidobenzylidene)benzohydrazidato]bis[(morpholine)zinc(II)], [Zn2(C14H10N2O3)2(C4H9NO)2], (II), consists of a neutral centrosymmetric dimer with a coplanar Zn2(,2 -O)2 core. The two ZnII centers are bridged by phenolate O atoms. Each ZnII center exhibits a distorted square-pyramidal stereochemistry, in which the four in-plane donors come from the O,N,O,-tridentate 2-hydroxy- N,-(2-oxidobenzylidene)benzohydrazidate(2,) ligand and a symmetry-related phenolate O atom, and the axial position is coordinated to the N atom from the morpholine molecule. There are intramolecular phenol,hydrazide O,H...N hydrogen bonds present in both (I) and (II). In (I), square-planar nickel complexes are linked by intermolecular morpholine,morpholine N,H...O hydrogen bonds, leading to a one-dimensional chain, while in (II) an infinite two-dimensional network is formed via intermolecular hydrogen bonds between the coordinated morpholine NH groups and the uncoordinated phenolate O atoms. [source] A two-dimensional network in the molecular salt 2-methylimidazolium hydrogen glutarate, and three-dimensional networks in the salts 2-methylimidazolium hydrogen succinate and 2-methylimidazolium hydrogen adipate monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Xiang-Gao Meng All three title compounds, C4H7N2+·C4H5O4,, (I), C4H7N2+·C5H7O4,, (II), and C4H7N2+·C6H9O4,·H2O, (III), can be regarded as 1:1 organic salts. The dicarboxylic acids join through short acid bridges into infinite chains. Compound (I) crystallizes in the noncentrosymmetric Cmc21 space group and the asymmetric unit consists of a hydrogen succinate anion located on a mirror plane and a 2-methylimidazolium cation disordered across the same mirror. The other two compounds crystallize in the triclinic P space group. The carboxylic acid H atom in (II) is disordered over both ends of the anion and sits on inversion centres between adjacent anions, forming symmetric short O...H...O bridges. Two independent anions in (III) sit across inversion centres, again with the carboxylic acid H atom disordered in short O...H...O bridges. The molecules in all three compounds are linked into two-dimensional networks by combinations of imidazolium,carboxylate N+,H...O and carboxylate,carboxylate O,H...O hydrogen bonds. The two-dimensional networks are further linked into three-dimensional networks by C,H...O hydrogen bonds in (I) and by Owater,H...O hydrogen bonds in (III). According to the ,pKa rule, such 1:1 types of organic salts can be expected unambiguously. However, a 2:1 type of organic salt may be more easily obtained in (II) and (III) than in (I). [source] Self-inclusion structure of 5,11,17,23-tetrakis(azidomethyl)-25,26,27,28-tetrahydroxycalix[4]arene, and 5,11,17,23-tetra- tert -butyl-25,27-bis(chloroacetoxy)-26,28-bis(2-pyridylmethoxy)calix[4]areneACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Mei Zhao In the structures of the two title calix[4]arene derivatives, C32H28N12O4, (I), and C60H68Cl2N2O6, (II), compound (I) adopts an open-cone conformation in which there are four intramolecular O,H...O hydrogen bonds, while compound (II) adopts a distorted chalice conformation where the two pendant pyridyl rings, one of which is disordered, are almost mutually perpendicular, with an interplanar angle of 79.2,(2) or 71.4,(2)°. The dihedral angles between the virtual plane defined by the four bridging methylene C atoms and the phenol rings are 120.27,(7), 124.03,(6), 120.14,(8) and 128.25,(7)° for (I), and 95.99,(8), 135.93,(7), 97.21,(8) and 126.10,(8)° for (II). In the supramolecular structure of (I), pairs of molecules associate by self-inclusion, where one azide group of the molecule is inserted into the cavity of the inversion-related molecule, and the association is stabilized by weak intermolecular C,H...N hydrogen bonds and ,(N3),,(aromatic) interactions. The molecular pairs are linked into a two-dimensional network by a combination of weak intermolecular C,H...N contacts. Each network is further connected to its neighbor to produce a three-dimensional framework via intersheet C,H...N hydrogen bonds. In the crystal packing of (II), the molecular components are linked into an infinite chain by intermolecular C,H...O hydrogen bonds. This study demonstrates the ability of calix[4]arene derivatives to form self-inclusion structures. [source] A two-dimensional network formed by self-associating silver(I) perchlorate with 3-[4-(2-thienyl)-2H -cyclopenta[d]pyridazin-1-yl]benzonitrileACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009Xiao-Yan Li In the organometallic silver(I) supramolecular complex poly[[silver(I)-,3 -3-[4-(2-thienyl)-2H -cyclopenta[d]pyridazin-1-yl]benzonitrile] perchlorate methanol solvate], {[Ag(C18H11N3S)](ClO4)·CH3OH}n, there is only one type of AgI center, which lies in an {AgN2S,} coordination environment. Two unsymmetric multidentate 3-[4-(2-thienyl)-2H -cyclopenta[d]pyridazin-1-yl]benzonitrile (L) ligands link two AgI atoms through ,,AgI interactions into an organometallic box-like unit, from which two 3-cyanobenzoyl arms stretch out in opposite directions and bind two AgI atoms from neighboring box-like building blocks. This results in a novel two-dimensional network extending in the crystallographic bc plane. These two-dimensional sheets stack together along the crystallographic a axis to generate parallelogram-like channels. The methanol solvent molecules and the perchlorate counter-ions are located in the channels, where they are fixed by intermolecular hydrogen-bonding interactions. This architecture may provide opportunities for host,guest chemistry, such as guest molecule loss and absorption or ion exchange. The new fulvene-type multidentate ligand L is a good candidate for the preparation of Cp,AgI -containing (Cp is cyclopentadienyl) organometallic coordination polymers or supramolecular complexes. [source] Poly[triaqua(,4 -4-carboxybenzenesulfonato-,4O:O,:O,,:O,,,)(4-carboxybenzenesulfonato-,O)strontium(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009G. Prochniak This study presents the coordination modes and two-dimensional network of a novel strontium(II) coordination polymer, [Sr(C7H5O5S)2(H2O)3]n. The eight-coordinate Sr2+ ion is in a distorted bis-disphenoidal coordination environment, surrounded by four sulfonate and one carboxyl O atom from five benzenesulfonate ligands, two of which are symmetry unique, and by three O atoms from three independent aqua ligands. The compound exhibits a monolayer structure with coordination bonds within and hydrogen bonds between the layers. The ,4 acid ligand bridges the metal ions in two dimensions to form a thick undulating monolayer with a hydrophobic interior and hydrophilic surfaces. A second independent monoanion is arranged outward from both sides of the monolayer and serves to link adjacent monolayers via carboxyl,water and water,carboxyl hydrogen bonds. [source] Hydrogen-bonded networks in 1-(4-methoxyphenyl)-2,2-dimethylpropan-1-olACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2007Marek Gli The asymmetric unit of the title compound, C12H18O2, contains two independent molecules. They differ only slightly in conformation but form completely different intermolecular hydrogen-bonded arrays. One molecule exhibits disorder in the hydroxy group region, but this does not influence the formation of hydrogen bonds. The bulky tert -butyl group on one side of the carbinol C atom and the benzene ring on the other side promote the formation of discrete dimeric motifs via hydrogen-bridged hydroxy groups. Dimers are further joined by strong hydroxy,methoxy O,H...O bonds to form chains with dangling alcohol groups. Weaker intermolecular C,H...O interactions mediate the formation of a two-dimensional network. [source] Hydrogen-bonded supramolecule of N,N,-bis(4-pyridylmethyl)oxalamide and a zigzag chain structure of catena -poly[[[dichloridocobalt(II)]-,- N,N,-bis(4-pyridylmethyl)oxalamide-,2N4:N4,] hemihydrate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2007Gene-Hsiang Lee N,N,-Bis(4-pyridylmethyl)oxalamide, C14H14N4O2, exists as a dimer which is extended into a two-dimensional network with other dimers through pyridine,amide hydrogen bonds. The crystal structure of the title coordination polymer, {[CoCl2(C14H14N4O2)]·0.5H2O}n, features a one-dimensional zigzag chain, in which the cobalt ion sits at a twofold symmetry position and adopts a tetrahedral geometry, and the bridging ligand lies on an inversion center and connects to CoII ions in a bis-monodentate mode. Furthermore, two interwoven chains create a cavity of ca 8.6 × 8.6,Å, which produces a three-dimensional channel. Water molecules are held in the channel by hydrogen bonds. [source] A two-dimensional manganese(II) coordination polymer: poly[[diaquamanganese(II)]-,-4,4-bipyridine-,2N:N,-,-(p -phenylenedioxydiacetato)-,2O:O,]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2004Shan Gao In the title two-dimensional coordination polymer, [Mn(1,4-BDOA)(4,4-bipy)(H2O)2]n [1,4-BDOA2, is the p -phenylenedioxydiacetate dianion (C10H8O6) and 4,4-bipy is 4,4-bipyridine (C10H8N2)], each MnII atom displays octahedral coordination by two O atoms of the 1,4-BDOA2, groups, two N atoms of the 4,4-bipy ligands and two solvent water molecules. The MnII atom, 4,4-bipy ligand and 1,4-BDOA2, group occupy different inversion centres. Adjacent MnII atoms are bridged by 1,4-BDOA2, groups and 4,4-bipy ligands, forming a two-dimensional network with Mn,Mn separations of 11.592,(2) and 11.699,(2),Å. Hydrogen bonds from a water O,H group link the layers in the third dimension. [source] 1-Methyl-1-phenyl-3-[1-hydroxyimino-2-(succinimido)ethyl]cyclobutaneACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2004Muharrem Dinçer In the title compound, C17H20N2O3, the cyclobutane ring is puckered, with a dihedral angle of 19.11,(15)°. The 1-phenyl and 3-[1-hydroxyimino-2-(succinimido)ethyl] groups are in cis positions. The molecules are linked by O,H,O and C,H,,(benzene) interactions, forming a two-dimensional network. [source] Displaced ,,, stacking and hydrogen bonds in 3-bromo- N -(2-hydroxy-1,1-dimethylethyl)benzamideACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2004Yao-Wen Wu The molecules of the title compound, C11H14BrNO2, are assembled into a two-dimensional network by a combination of hydrogen bonds and stacking interactions. The phenyl rings are stacked along the c direction by displaced ,,, interactions, forming a lipophilic layer. The aliphatic amide residues are interconnected along [100] by O,H,O, N,H,O and C,H,O hydrogen bonds, forming hydrophilic layers. [source] Polymeric hexa-,-nicotinato-tricadmium(II) tetrahydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2003Hong-Ji Chen The title polymeric complex, poly[tetraaquatricadmium(II)-hexa-,-nicotinato], [Cd3(C6H4NO2)6(H2O)4]n, exhibits two types of metal centers, i.e. a seven-coordinated Cd atom and a six-coordinated Cd atom located on an inversion center. The seven-coordinated Cd atoms are linked by ,3N:O,O,-nicotinate bridges into one-dimensional chains that are further linked by ,2N,O -nicotinate,Cd2,,2N,O -nicotinate bridges into a two-dimensional network which is parallel to the xy plane and which contains large 24- and 36-membered rings. [source] Intermolecular hydrogen bonding of the two independent molecules of N -3,5-dinitrobenzoyl- l -leucineACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2000John F. Gallagher The title compound, C13H15N3O7, crystallizes as two independent molecules which differ in their conformation. Intermolecular hydrogen bonding between the amide and carboxylic acid groups as N,H,O=C interactions results in the formation of one-dimensional chains with N,O distances of 2.967,(6) and 3.019,(6),Å. Neighbouring chains are linked by C=O,H,O interactions to form a two-dimensional network, with O,O distances of 2.675,(6) and 2.778,(6),Å. [source] The new chiral ligand 3-ethoxy-4-[(1R,2S)-(2-hydroxy-1,2-diphenylethyl)amino]-3-cyclobutene-1,2-dioneACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2000Haibing Zhou The asymmetric unit of C20H19NO4 contains two molecules with slightly different conformations. In the crystal, the molecules are linked by O,H,O and N,H,O hydrogen bonds [O,O 2.764,(3) and 2.811,(3),Å; N,O 2.907,(3) and 2.968,(3),Å] to form a two-dimensional network. [source] Encapsulation of Cyanometalates by a Tris-macrocyclic Ligand Tricopper(II) Complex: Syntheses, Structural Variation, and Magnetic Exchange Coupling PathwaysCHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2006Mihail Atanasov Prof. Dr. Abstract The reaction of [M(CN)6]3, (M=Cr3+, Mn3+, Fe3+, Co3+) and [M(CN)8]4,/3, (M=Mo4+/5+, W4+/5+) with the trinuclear copper(II) complex of 1,3,5-triazine-2,4,6-triyltris[3-(1,3,5,8,12-pentaazacyclotetradecane)] ([Cu3(L)]6+) leads to partially encapsulated cyanometalates. With hexacyanometalate(III) complexes, [Cu3(L)]6+ forms the isostructural host,guest complexes [{[Cu3(L)(OH2)2][M(CN)6]2}{M(CN)6}],[M(CN)6],30,H2O with one bridging, two partially encapsulated, and one isolated [M(CN)6]3, unit. The octacyanometalates of Mo4+/5+ and W4+/5+ are encapsulated by two tris-macrocyclic host units. Due to the stability of the +IV oxidation state of Mo and W, only assemblies with [M(CN)8]4, were obtained. The Mo4+ and W4+ complexes were crystallized in two different structural forms: [{Cu3(L)(OH2)}2{Mo(CN)8}](NO3)8,15,H2O with a structural motif that involves isolated spherical [{Cu3(L)(OH2)}2{M(CN)8}]8+ ions and a "string-of-pearls" type of structure [{[Cu3(L)]2[M(CN)8]}{M(CN)8}](NO3)4, 20,H2O, with [M(CN)8]4, ions that bridge the encapsulated octacyanometalates in a two-dimensional network. The magnetic exchange coupling between the various paramagnetic centers is characterized by temperature-dependent magnetic susceptibility and field-dependent magnetization data. Exchange between the Cu,,,Cu pairs in the [Cu3(L)]6+ "ligand" is weakly antiferromagnetic. Ferromagnetic interactions are observed in the cyanometalate assemblies with Cr3+, exchange coupling of Mn3+ and Fe3+ is very small, and the octacoordinate Mo4+ and W4+ systems have a closed-shell ground state. [source] A Theoretical Description of Elastic Pillar Substrates in Biophysical ExperimentsCHEMPHYSCHEM, Issue 8 2005Camilla Mohrdieck Dr. Abstract Arrays of elastic pillars are used in biophysical experiments as sensors for traction forces. The evaluation of the forces can be complicated if they are coupled to the pillar displacements over large distances. This is the case if many of the pillars are interconnected by elastic linkages as, for example, in fiber networks that are grown on top of pillars. To calculate the traction forces in such a network, we developed a set of nonlinear inhomogeneous equations relating the forces in the linking elements to the resulting pillar deflections. We chose a homogeneous, activated two-dimensional network of cytoskeletal actin filaments to illustrate that a pillar substrate is generally not a force sensor but a force-gradient sensor. In homogeneous networks the forces acting along the filaments can be approximated by analyzing only pillar deflections in the edge zones of the substrate and by integration over the corresponding force gradients. [source] Synthesis, Structure and Characterization of Two-dimensional Network Copper Complex [Cu3(nta)2(azpy)2(H2O)2]·6H2OCHINESE JOURNAL OF CHEMISTRY, Issue 2 2002Bao-Long Li Abstract The copper(II) complex[Cu3(nta)2(azpy)2(H2O)2]·6H2O (nta = nitrilotriacetate, azpy = 4,4,-azobispyridine) has been synthesized and characterized. The X-ray analysis reveals that there are two kinds of copper(II) coordination environments. Cu(1) has a distorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1) is linked to Cu(2) through nta and bound to Cu(1C) by azpy, and Cu(2) is linked to Cu(2A) through azpy, which extends to two-dimensional network with large rhombus 1.2 nm × 1.7 nm. [source] Layered [BaM(C3H2O4)2(H2O)4] (M = Fe or Co) Complexes , Spectroscopic, Magnetic and Thermal StudyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2003Izaskun Gil de Muro Abstract Complexes with formula [BaM(C3H2O4)2(H2O)4], where M = Fe or Co, were synthesised and characterised. These two types of complexes are isostructural and crystallise in the Pccn space group. Their structure consists of two-dimensional networks of octahedral MO6 polyhedra in which the transition metal ions are coordinated by bridging malonate ligands, through the O-C-O atoms. These M-malonate units are extended along the crystallographic [101] plane. Spectroscopic data are consistent with the cations being in a high-spin octahedral symmetry. The two types of compounds exhibit 2D antiferromagnetic interactions as well as weak ferromagnetism below the Néel temperature, as a result of an intralayer misalignment of the spins. Thermal treatment of the metallo-organic precursors gave rise to BaMO3,y oxides at lower temperatures and reaction times than those found in the literature using the ceramic method. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003). [source] | ||||||||||||||||||||||||||||