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Weak C (weak + c)
Selected AbstractsMonitoring structural transformations in crystals.ACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2008Variations in crystal and molecular structures, brought about by the intramolecular [4,+,4] photocycloaddition of bi(anthracene-9,10-dimethylene), were monitored using X-ray diffraction. The cell volume increased by 0.8% until the reaction was ca 40% complete, and afterwards decreased by 1.6% during the remainder of the photoreaction. The changes of the a and b lattice parameters were correlated with the changes of the molecular shape and packing. The distance between the directly reacting C atoms varied in a manner not observed for other photochemical reactions in crystals. It was constant until ca 20% photoreaction progress, then decreased, and later stabilized from ca 40% photoreaction progress. This phenomenon was explained by interplay between stress resulting from the presence of product molecules and the rigidity of reactant molecules. Changes of the orientation of molecules during the photoreaction were smaller than in the case of other monitored photochemical reactions in crystals owing to similarities in the shape and packing of reactant and product molecules. Weak C,H..., hydrogen bonds exist among reactant molecules in the pure reactant and partly reacted crystals. [source] Weak intermolecular interactions in isomorphous 5-(2-chloroethoxy)-2,3-dihydro-1,4-benzodioxine and 5-(2-bromoethoxy)-2,3-dihydro-1,4-benzodioxine: bonding or nonbonding interactionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009Rafal Kruszynski The title compounds, C10H11ClO3, (I), and C10H11BrO3, (II), are isomorphous and effectively isostructural; all of the interatomic distances and angles are normal. The structures exhibit long intermolecular C,H...O and C,H..., contacts with attractive energies ranging from 1.17 to 2.30,kJ,mol,1. Weak C,H...O hydrogen bonds form C(3) and C(4) motifs, combining to form a two-dimensional R34(12) net. No face-to-face stacking interactions are observed. [source] Weak C,H...N[triple-bond]C hydrogen bonds in the structures of two poly(cyano)-substituted ring systemsACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2007Peter G. Jones In benzene-1,2,3-tricarbonitrile, C9H3N3, the packing of the two independent molecules is three-dimensional and complex, involving inter alia bifurcated (C,H)2...N systems from neighbouring CH groups. In [2.2]paracyclophane-4,5,12,13-tetracarbonitrile, C20H12N4, the [2.2]paracyclophane systems display the usual distortions, namely lengthened C,C bonds and widened sp3 angles in the bridges, narrow angles in the six-membered rings at the bridgehead atoms, and flattened boat conformations of the rings. The molecules are linked by a series of C,H...N interactions to form layers parallel to the ab plane. [source] Interpenetrating 2D Manganese(II) Coordination Polymer Supported by 4,4,-Bis(dimethoxyphosphorylmethyl)-biphenyl LigandsCHINESE JOURNAL OF CHEMISTRY, Issue 6 2009Xiangdong ZHANG Abstract A novel coordination polymer [Mn(bdpbp)2(NO3)2]n (1), where bdpbp=4,4,-bis(dimethoxyphosphoryl- methyl)biphenyl, was prepared under mild condition. The structure has been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, luminescent property and thermogravimetric analyses. Structure of 1 exhibits infinite grid frameworks and forms two fold interpenetrating nets. Weak C,H···O hydrogen bonds ensure the formation and stability of a three dimensional supramolecular network. [source] (Pyrazole)silver(I) and -gold(I) Complexes with Strong and Weak Hydrogen-Bonding Interactions as the Basis of One- or Two-Dimensional StructuresEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2004M. Luz Gallego Abstract New AuI/AgI complexes containing one or two substituted pyrazole ligands [Au(Hpzbp2)(PPh3)](p -CH3C6H4SO3) [Hpzbp2 = 3,5-bis(4- n -butoxyphenyl)pyrazole] (1) and [M(HpzR2)2]nX [HpzR2 = Hpzbp2, M = Au, n = 1, X = p -CH3C6H4SO3 (2), NO3, (3); n = 2, X = 1,5-naphthalenedisulfonate (1,5nds) (4); HpzR2 = Hpzbp2, M = Ag, n = 1, X = BF4, (5), CF3SO3, (6); HpzR2 = HpzNO2 (3,5-dimethyl-4-nitropyrazole), M = Ag, n = 1, X = BF4, (7), CF3SO3, (8)], have been prepared and characterized. Compounds 1, 2, 5 and 8 have been proved to be useful for supramolecular assembly from their single X-ray diffraction analysis. In all cases strong hydrogen bonds maintain the cationic units bonded to their corresponding counterions. The crystal packing arrangement of 1, 2 and 5 is, however, determined by weak C,H···O/F hydrogen-bonding interactions involving the remaining O/F atoms of the counterion. By contrast, for 8 a two-dimensional layer-type polymeric network is formed by ,···, (NO2···NO2) and coordinative Ag···O interactions in which the NO2 substituent on the pyrazole is implicated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Trans -cinnamic acid and coumarin-3-carboxylic acid: experimental charge-density studies to shed light on [2,+,2] cycloaddition reactionsACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2009Judith A. K. Howard As part of an ongoing series of experimental charge-density investigations into the intra- and intermolecular interactions present in compounds which undergo solid-state [2,+,2] cycloaddition reactions, the charge-density analyses of trans -cinnamic acid and coumarin-3-carboxylic acid are reported. Thus, high-resolution single-crystal X-ray diffraction data were recorded at 100,K for trans -cinnamic acid (sin,,/,max = 1.03,Å,1) and coumarin-3-carboxylic acid (sin,,/,max = 1.19,Å,1). In addition to the anticipated O,H...O hydrogen bonds weak C,H...O interactions were identified in both structures along with very weak intermolecular interactions between pairs of molecules that undergo solid-state [2,+,2] cycloaddition reactions upon irradiation. [source] Supramolecular aggregation in 4,4,-bipyridin-1,1,-ium dichloride, 4,4,-bipyridin-1,1,-ium dinitrate and 4,4,-bipyridin-1-ium bromideACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2003Peter Abeta Iyere 4,4,-Bipyridin-1,1,-ium dichloride [C10H10Cl2N2 (I)] and 4,4,-bipyridin-1,1,-ium dinitrate [C10H10N4O6 (II)] have been prepared and the crystal structures determined at 90.0,(2),K. Molecules of (I) are linked by two chlorine-bridged, three-centered N,H,Cl hydrogen bonds into chains along the b axis. The chains are coupled by weak C,H,Cl interactions into a molecular ladder along the c direction. In (II) each nitrate is coordinated to four bipyridinium ions through the interplay of the N,H,O and C,H,O contacts, resulting in a three-dimensional zigzag sheet on the ab plane. The sheets stack along the c axis. In 4,4,-bipyridin-1-ium bromide monohydrate [C10H9N2+·Br,·H2O (III)] the bipyridinium ions are linked by three-center N,H,N, hydrogen bonds in a head-to-tail fashion to form chains along the b axis. The chains are linked by C,H,Br and C,H,OH2 into a three-dimensional framework. [source] Polymorphs and pseudopolymorphs of N,N,-dithiobisphthalimideACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2002Dorcas M. M. Farrell N,N,-Dithiobisphthalimide, C16H8N2O4S2 (I), forms a wide range of polymorphs and solvates (pseudopolymorphs). When (I) is crystallized from methanol it yields a solvent-free polymorph (4), in Pna21 with Z, = 1, in which the molecules are linked into chains by a single C,H,O hydrogen bond: crystallization from either acetonitrile or dimethylformamide produces a monoclinic polymorph (5), in P21/c with Z, = 2, also solvent-free, in which the molecules are linked into molecular ladders. Nitromethane forms a monosolvate, C16H8N2O4S2·CH3NO2 (6), in P21/c with Z, = 1, in which the solvent molecules are linked to the molecules of (I) not only via a conventional C,H,O hydrogen bond but also via a polarized multicentre interaction involving all three C,H bonds of the solvent molecule. Chlorobenzene forms a precise hemisolvate, C16H8N2O4S2·0.5C6H5Cl (7), in P with Z, = 1, while ethylbenzene forms an approximate hemisolvate 2C16H8N2O4S2·0.913C6H5C2H5·0.087H2O (8), in P21/c with eight molecules of (I) per unit cell. In both solvates the molecules of (I) are linked, in (7) by ,,, stacking interactions augmented by weak C,H,O hydrogen bonds and in (8) by stronger C,H,O hydrogen bonds: the solvent molecules lie in isolated cavities, disordered across inversion centres in (7) and fully ordered in general positions in (8). Crystallization of (I) either from tetrahydrofuran or from wet tert -butanol yields isomorphous solvates (9) and (10), respectively, in C2/c with Z, = 0.5, in which molecules of (I) lie across twofold rotation axes and are linked by ,,, stacking interactions and very weak C,H,O hydrogen bonds, forming a framework enclosing continuous channels: highly disordered solvent molecules lie within these channels. p -Xylene and toluene form isomorphous hemisolvates (11) and (12) with unit cells metrically very similar to those of (9) and (10), but in P21/n with Z, = 1: in these two solvates the molecules of (I) are linked into a framework by very short C,H,O hydrogen bonds; the solvent molecules lie within continuous channels, but they are localized across inversion centres so that the toluene is disordered across an inversion centre. [source] 2-{[(3-Fluorophenyl)amino]methylidene}-3-oxobutanenitrile and 5-{[(3-fluorophenyl)amino]methylidene}-2,2-dimethyl-1,3-dioxane-4,6-dione: X-ray and DFT studiesACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010Vratislav Langer In the crystal structures of the title compounds, C11H9FN2O, (I), and C13H12FNO4, (II), the molecules are joined pairwise via different hydrogen bonds and the constituent pairs are crosslinked by weak C,H...O hydrogen bonds. The basic structural motif in (I), which is partially disordered, comprises pairs of molecules arranged in an antiparallel fashion which enables C,H...N[triple-bond]C interactions. The pairs of molecules are crosslinked by two weak C,H...O hydrogen bonds. The constituent pair in (II) is formed by intramolecular bifurcated C,H...O/O, and combined inter- and intramolecular N,H...O hydrogen bonds. In both structures, F atoms form weak C,F...H,C interactions with the H atoms of the two neighbouring methyl groups, the H...F separations being 2.59/2.80 and 2.63/2.71,Å in (I) and (II), respectively. The bond orders in the molecules, estimated using the natural bond orbitals (NBO) formalism, correlate with the changes in bond lengths. Deviations from the ideal molecular geometry are explained by the concept of non-equivalent hybrid orbitals. The existence of possible conformers of (I) and (II) is analysed by molecular calculations at the B3LYP/6,31+G** level of theory. [source] Forced twin-chair conformation in 7-benzoyl- and 7-phenylacetyl- r -2,c -4,t -6,t -8-tetraphenyl-3-thia-7-azabicyclo[3.3.1]nonanes with 1,3-diaxial phenyl groups in the piperidine ring: single- and double-layered supramolecular sheets built from C,H...O and C,H...,(arene) hydrogen bondsACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010Chinniah Sakthivel The crystal structures of 7-benzoyl- r -2,c -4,t -6,t -8-tetraphenyl-3-thia-7-azabicyclo[3.3.1]nonane, C38H33NOS, (I), and r -2,c -4,t -6,t -8-tetraphenyl-7-phenylacetyl-3-thia-7-azabicyclo[3.3.1]nonane [systematic name: 2-phenyl-1-(r -2,c -4,t -6,t -8-tetraphenyl-3-thia-7-azabicyclo[3.3.1]nonan-7-yl)ethanone], C39H35NOS, (II), both reveal a forced twin-chair conformation with the 1,3-diaxial phenyl groups in the piperidine ring, and flattening at the N-atom end of the piperidine ring of the bicyclic system. In the crystal structure of (I), molecules are linked into sheets by a combination of two weak C,H...O and one C,H...,(arene) hydrogen bond, while in the crystal structure of (II), the molecules extend into double-layered sheets assisted by three C,H...,(arene) hydrogen bonds. [source] 4-Methoxyanilinium tetrafluoroborate,dibenzo-18-crown-6 (1/1)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010Xue-qun Fu In the structure of the complex of dibenzo-18-crown-6 [systematic name: 2,5,8,15,18,21-hexaoxatricyclo[20.4.0.09,14]hexacosa-1(26),9,11,13,22,24-hexaene] with 4-methoxyanilinium tetrafluoroborate, C7H10NO+·BF4,·C20H24O6, the protonated 4-methoxyanilinium (MB-NH3+) cation forms a 1:1 supramolecular rotator,stator complex with the dibenzo-18-crown-6 molecule via N,H...O hydrogen bonds. The MB-NH3+ group is attached from the convex side of the bowl-shaped crown, in contrast with similar ammonium cations that nest in the curvature of the bowl. The cations are associated via C,H..., interactions, while the cations and anions are linked by weak C,H...F hydrogen bonds, forming cation,crown,anion chains parallel to [011]. [source] Intermolecular C,H..., interactions in 1,5-diphenyl-3-(2-pyridyl)-2-pyrazolineACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2010Miquel Barceló-Oliver The title compound, C20H17N3, is a derivative of 1,3,5-triaryl-2-pyrazoline and can act as an N,N,-bidentate ligand. This molecule features strong fluorescence that can be explained by an extended pyridyl,C=N,N,phenyl system. The three-dimensional structure is formed by means of an extended network of weak C,H..., hydrogen bonds supported by ,,, interactions. [source] Hydrogen-bonded supramolecular networks of N,N,-bis(4-pyridylmethyl)oxalamide and 4,4,-{[oxalylbis(azanediyl)]dimethylene}dipyridinium dinitrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2010Gene-Hsiang Lee The molecule of N,N,-bis(4-pyridylmethyl)oxalamide, C14H14N4O2, (I) or 4py-ox, has an inversion center in the middle of the oxalamide group. Adjacent molecules are then linked through intermolecular N,H...N and C,H...O hydrogen bonds, forming an extended supramolecular network. 4,4,-{[Oxalylbis(azanediyl)]dimethylene}dipyridinium dinitrate, C14H16N4O22+·2NO3,, (II), contains a diprotonated 4py-ox cation and two nitrate counter-anions. Each nitrate ion is hydrogen bonded to four 4py-ox cations via intermolecular N,H...O and C,H...O interactions. Adjacent 4py-ox cations are linked through weak C,H...O hydrogen bonding between an ,-pyridinium C atom and an oxalamide O atom, forming a two-dimensional extended supramolecular network. [source] A hydrogen-bonded dimer in 6-(4-bromophenyl)-3-methyl-1-phenyl-4,5-dihydro-1H -pyrazolo[3,4- b]pyridine and a chain of rings built from N,H...N and C,H...,(pyridine) hydrogen bonds in 3-(4-nitrophenyl)-4-phenyl-1H -pyrazolo[3,4- b]pyridineACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010Jairo Quiroga In 6-(4-bromophenyl)-3-methyl-1-phenyl-4,5-dihydro-1H -pyrazolo[3,4- b]pyridine, C19H16BrN3, the reduced pyridine ring adopts a conformation that is close to a screw-boat form. Molecules are linked by pairs of symmetry-related C,H...,(arene) hydrogen bonds into cyclic centrosymmetric dimers. Molecules of 3-(4-nitrophenyl)-4-phenyl-1H -pyrazolo[3,4- b]pyridine, C18H12N4O2, are linked into centrosymmetric R22(8) dimers by pairs of symmetry-related N,H...N hydrogen bonds, and these dimers are linked by pairs of C,H...,(pyridine) hydrogen bonds to form a chain of edge-fused rings, or a molecular ladder, along [100]. The molecular aggregation in this compound is completed by two weak C,H...O hydrogen bonds, one of which links the chains along [100] into sheets. [source] Asymmetric ruthenium-catalysed [2+2] cycloadditions between bicyclic alkenes and chiral aryl-substituted acetylenic acyl camphorsultam alkynesACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Jordan D. Goodreid The regio- and absolute stereochemistry of (7S)- N -[4-(3-thienyl)tricyclo[4.2.1.02,5]non-3-en-3-ylcarbonyl]-2,10-camphorsultam tetrahydrofuran hemisolvate, C24H29NO3S2·0.5C4H8O, and (7S)- N -[4-(4-tolyl)tricyclo[4.2.1.02,5]non-3-en-3-ylcarbonyl]-2,10-camphorsultam, C27H33NO3S, have been established. One contains a half-occupancy tetrahydrofuran solvent molecule located on a twofold axis and the other contains two crystallographically unique molecules which are nearly identical. The extended structures of both complexes can be explained via weak C,H...O interactions, which link the molecules together into two-dimensional sheets in the ab plane for the thienyl complex and ultimately into a three-dimensional structure for the tolyl derivative. The stereochemistry of both structures confirms that [2+2] cycloadditions of bicyclic alkenes and alkynes catalysed by ruthenium are exclusively exo. [source] Trans influence in a mer -octahedral triiodidolanthanide: triiodidotris(tetrahydrofuran-,O)ytterbium(III)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Thomas J. Emge The structure of the six-coordinate title complex, [YbI3(C4H8O)3], is the first mer -octahedral form of an LnI3L3 lanthanide (Ln) compound with neutral L ligands, and is closely related to that of several of the seven-coordinate LnX3L4 series of compounds, where X = Cl, Br or I and L = tetrahydrofuran (THF), isopropanol, pyridine or water. A structural trans effect can be assigned to YbI3(THF)3, in contrast to the LnX3L4 compounds, where steric and crystal packing effects are significant. The Yb,I bond lengths are 2.9543,(4) and 2.9151,(6),Å for I trans and cis to I, respectively, and the Yb,O bond lengths are 2.299,(5) and 2.251,(3),Å for O trans and cis to I, respectively. The crystal packing allows for six contact distances as weak C,H...I interactions in the range 3.10,3.24,Å. The title molecule has a crystallographic twofold axis passing through a THF O atom, the trans I atom and the Yb atom. [source] Insight into the structures of [M(C5H4I)(CO)3] and [M2(C12H8)(CO)6] (M = Mn and Re) containing strong I...O and ,(CO),,(CO) interactionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Alexander S. Romanov The compounds tricarbonyl(,5 -1-iodocyclopentadienyl)manganese(I), [Mn(C5H4I)(CO)3], (I), and tricarbonyl(,5 -1-iodocyclopentadienyl)rhenium(I), [Re(C5H4I)(CO)3], (III), are isostructural and isomorphous. The compounds [,-1,2(,5)-acetylenedicyclopentadienyl]bis[tricarbonylmanganese(I)] or bis(cymantrenyl)acetylene, [Mn2(C12H8)(CO)6], (II), and [,-1,2(,5)-acetylenedicyclopentadienyl]bis[tricarbonylrhenium(I)], [Re2(C12H8)(CO)6], (IV), are isostructural and isomorphous, and their molecules display inversion symmetry about the mid-point of the ligand C[triple-bond]C bond, with the (CO)3M(C5H4) (M = Mn and Re) moieties adopting a transoid conformation. The molecules in all four compounds form zigzag chains due to the formation of strong attractive I...O [in (I) and (III)] or ,(CO),,(CO) [in (I) and (IV)] interactions along the crystallographic b axis. The zigzag chains are bound to each other by weak intermolecular C,H...O hydrogen bonds for (I) and (III), while for (II) and (IV) the chains are bound to each other by a combination of weak C,H...O hydrogen bonds and ,(Csp2),,(Csp2) stacking interactions between pairs of molecules. The ,(CO),,(CO) contacts in (II) and (IV) between carbonyl groups of neighboring molecules, forming pairwise interactions in a sheared antiparallel dimer motif, are encountered in only 35% of all carbonyl interactions for transition metal,carbonyl compounds. [source] (E)-2-[(4-Chlorophenyl)iminomethyl]-5-methoxyphenol and (E)-2-[(2-chlorophenyl)iminomethyl]-5-methoxyphenol: X-ray and DFT-calculated structuresACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009ak Ko The crystal structures of the title 4-chlorophenyl, (I), and 2-chlorophenyl, (II), compounds, both C14H12ClNO2, have been determined using X-ray diffraction techniques and the molecular structures have also been optimized at the B3LYP/6-31 G(d,p) level using density functional theory (DFT). The X-ray study shows that the title compounds both have strong intramolecular O,H...N hydrogen bonds and that the crystal networks are primarily determined by weak C,H..., and van der Waals interactions. The strong intramolecular O,H...N hydrogen bond is evidence of the preference for the phenol,imine tautomeric form in the solid state. The IR spectra of the compounds were recorded experimentally and also calculated for comparison. The results from both the experiment and theoretical calculations are compared in this study. [source] 4,4,-Methylenediphenol,4,4,-bipyridine (2/3): decarboxylation of 5,5,-methylenedisalicylic acid under hydrothermal conditionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Zhi-Hui Zhang Reaction of 5,5,-methylenedisalicylic acid (5,5,-H4mdsa) with 4,4,-bipyridine (4,4,-bipy) and manganese(II) acetate under hydrothermal conditions led to the unexpected 2:3 binary cocrystal 4,4,-methylenediphenol,4,4,-bipyridine (2/3), C13H12O2·1.5C10H8N2 or (4,4,-H2dhdp)(4,4,-bipy)1.5, which is formed with a concomitant decarboxylation. The asymmetric unit contains one and a half 4,4,-bipy molecules, one of which straddles a centre of inversion, and one 4,4,-H2dhdp molecule. O,H...N interactions between the hydroxy and pyridyl groups lead to a discrete ribbon motif with an unusual 2:3 stoichiometric ratio of strong hydrogen-bonding donors and acceptors. One of the pyridyl N-atom donors is not involved in hydrogen-bond formation. Additional weak C,H...O interactions between 4,4,-bipy and 4,4,-H2dhdp molecules complete a two-dimensional bilayer supramolecular structure. [source] Two polymorphs of N -(2,6-difluorophenyl)formamideACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Bernard Omondi The structures of two distinct polymorphic forms of N -(2,6-difluorophenyl)formamide, C7H5F2NO, have been studied using single crystals obtained under different crystallizing conditions. The two forms crystallize in different space groups, viz. form (Ia) in the orthorhombic Pbca and form (Ib) in the monoclinic P21 space group. Each polymorph crystallizes with one complete molecule in the asymmetric unit and they have a similar molecular geometry, showing a trans conformation with the formamide group being out of the plane of the aromatic ring. The packing arrangements of the two polymorphs are quite different, with form (Ia) having molecules that are stacked in an alternating arrangement, linked into chains of N,H...O hydrogen bonds along the crystallographic a direction, while form (Ib) has its N,H...O hydrogen-bonded molecules stacked in a linear fashion. A theoretical study of the two structures allows information to be gained regarding other contributing interactions, such as ,,, and weak C,H...F, in their crystal structures. [source] Hydrogen-bonded zigzag chains in 2,2,-dithiodibenzoic acid,1,3-di-4-pyridylpropane (1/1)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Li-Li Wang The title 1:1 cocrystal, C14H10O4S2·C13H14N2 or H2L·bpp, has the two components connected by O,H...N hydrogen bonds to generate a one-dimensional zigzag chain running along the crystallographic a direction. These chains are further stacked into a three-dimensional supramolecular network by weak C,H...O and C,H..., contacts. Comparison of the structural differences with previous findings suggests that deprotonated forms, hydrogen-bonding sites and flexible ligand conformations become significant factors that influence the topological arrangement and binding stoichiometry of the resulting cocrystals. [source] `Segmented' crystals solved using synchrotron radiation: (2S,3R,4S,5R)-4-(10,10-dimethyl-3,3-dioxo-3,6 -thia-4-azatricyclo[5.2.1.01,5]decan-4-ylcarbonyl)-2,6-diphenylperhydropyrrolo[3,4- c]pyrrole-1,3-dioneACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Graeme J. Gainsford The title compound, C29H31N3O5S, forms needle-shaped `segmented' crystals, thereby inhibiting successful single-crystal data collection using conventional laboratory facilities. One crystallite of dimensions 0.15 × 0.03 × 0.01,mm yielded sufficent single-crystal diffraction data on the Australian Synchrotron PX1 beamline. The two independent molecules in the asymmetric unit are nearly superimposable and show only minor conformational deviations from closely related compounds. The molecules pack using one N,H...O hydrogen bond and several phenyl C,H...O(=S), phenyl C,H...O(=C) and methylene C,H...O(=C) hydrogen bonds and weak C,H..., interactions. [source] N,N,-Dimethylpyrazinediium bis(tetrafluoroborate) and N,N,-diethylpyrazinediium bis(tetrafluoroborate): new examples of anion,, triadsACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Jianjiang Lu Crystallization of N,N,-dimethylpyrazinediium bis(tetrafluoroborate), C6H10N22+·2BF4,, (I), and N,N,-diethylpyrazinediium bis(tetrafluoroborate), C8H14N22+·2BF4,, (II), from dried acetonitrile under argon protection has permitted their single-crystal studies. In both crystal structures, the pyrazinediium dications are located about an inversion center (located at the ring center) and each pyrazinediium aromatic ring is ,-bonded to two centrosymmetrically related BF4, anions. Strong anion,, interactions, as well as weak C,H...F hydrogen bonds, between BF4, and pyrazinediium ions are present in both salts. [source] The crucial role of C,H...O and C=O..., interactions in the building of three-dimensional structures of dicarboxylic acid,biimidazole compoundsACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Xiao-Li Gao The supramolecular architectures of three dicarboxylic acid,biimidazole compounds, namely, 2,2,-biimidazolium malonate, C6H8N42+·C3H2O42,, (I), 2,2,-bi(1H -imidazole) succinic acid, C6H6N4·C4H6O4, (II), and 2,2,-biimidazolium 2,2,-iminiodiacetate chloride, C6H8N42+·C4H6NO4,·Cl,, (III), are reported. The crystal structures are assembled by the same process, namely double conventional N,H...O or O,H...N hydrogen bonds link the dicarboxylates and biimidazoles to form tapes, which are stacked in parallel through lone-pair,aromatic interactions between carbonyl O atoms and biimidazole groups and are further linked via weak C,H...O interactions. The C=O..., interactions involved in stacking the tapes in (II) and the C,H...O interactions involved in linking the tapes in (II) and (III) demonstrate the crucial role of these interactions in the crystal packing. There is crystallographically imposed symmetry in all three structures. In (I), two independent malonate anions have their central C atoms on twofold axes and two biimidazolium dications each lie about independent inversion centres; in (II), the components lie about inversion centres, while in (III), the unique cation lies about an inversion centre and the iminiodiacetate and chloride anions lie across and on a mirror plane, respectively. [source] From small structural modifications to adjustment of structurally dependent properties: 1-methyl-3,5-bis[(E)-2-thienylidene]-4-piperidone and 3,5-bis[(E)-5-bromo-2-thienylidene]-1-methyl-4-piperidoneACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Paul Tongwa The molecules of the title compounds, C16H15NOS2, (I), and C16H13Br2NOS2, (II), are E,E -isomers and consist of an extensive conjugated system, which determines their molecular geometries. Compound (I) crystallizes in the monoclinic space group P21/c. It has one thiophene ring disordered over two positions, with a minor component contribution of 0.100,(3). Compound (II) crystallizes in the noncentrosymmetric orthorhombic space group Pca21 with two independent molecules in the unit cell. These molecules are related by a noncrystallographic pseudo-inversion center and possess very similar geometries. The crystal packings of (I) and (II) have a topologically common structural motif, viz. stacks along the b axis, in which the molecules are bound by weak C,H...O hydrogen bonds. The noncentrosymmetric packing of (II) is governed by attractive intermolecular Br...Br and Br...N interactions, which are also responsible for the very high density of (II) (1.861,Mg,m,3). [source] 3-[5-(4-Chlorophenyl)-1-(4-methoxyphenyl)-1H -pyrazol-3-yl]propionic acid and the corresponding methyl esterACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Isuru R. Kumarasinghe The synthesis of 3-[5-(4-chlorophenyl)-1-(4-methoxyphenyl)-1H -pyrazol-3-yl]propionic acid, C19H17ClN2O3, (I), and its corresponding methyl ester, methyl 3-[5-(4-chlorophenyl)-1-(4-methoxyphenyl)-1H -pyrazol-3-yl]propionate, C20H19ClN2O3, (II), is regiospecific. However, correct identification of the regioisomer formed by spectroscopic techniques is not trivial and single-crystal X-ray analysis provided the only means of unambiguous structure determination. Compound (I) crystallizes with Z, = 2. The propionic acid groups of the two crystallographically unique molecules form a hydrogen-bonded dimer, as is typical of carboxylic acid groups in the solid state. Conformational differences between the methoxybenzene and pyrazole rings give rise to two unique molecules. The structure of (II) features just one molecule in the asymmetric unit and the crystal packing makes greater use than (I) of weak C,H...A interactions, despite the lack of any functional groups for classical hydrogen bonding. [source] (E)-Methyl 2-[(2-fluorophenyl)aminomethylene]-3-oxobutanoate: X-ray and density functional theory (DFT) studyACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Vratislav Langer The title compound, C12H12FNO3, a potential precursor for fluoroquinoline synthesis, is essentially planar, with the most outlying atoms displaced from the best-plane fit through all non-H atoms by 0.163,(2) and 0.118,(2),Å. Molecules are arranged in layers oriented parallel to the (011) plane. The arrangement of the molecules in the structure is controlled mainly by electrostatic interactions, as the dipole moment of the molecule is 5.2,D. In addition, the molecules are linked by a weak C,H...O hydrogen bond which gives rise to chains with the base vector [1,1,1]. Electron transfer within the molecule is analysed using natural bond orbital (NBO) analysis. Deviations from the ideal molecular geometry are explained by the concept of non-equivalent hybrid orbitals. [source] Quinolin-6-ol at 100,KACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009Anna Michta The title compound, C9H7NO, has two symmetry-independent molecules in the asymmetric unit, which have different conformations of the hydroxy group with respect to the quinoline ring. One of the molecules adopts a cis conformation, while the other shows a trans conformation. Each type of independent molecule links into a separate infinite O,H...N hydrogen-bonded chain with the graph-set notation C(7). These chains are perpendicular in the unit cell, one extended in the a -axis direction and the other in the b -axis direction. There is also a weak C,H...O hydrogen bond with graph-set notation D(2), which runs in the c -axis direction and joins the two separate O,H...N chains. The significance of this study lies in the comparison drawn between the experimental and calculated data of the crystal structure of the title compound and the data of several other derivatives possessing the hydroxy group or the quinoline ring. The correlation between the IR spectrum of this compound and the hydrogen-bond energy is also discussed. [source] Manganese(II) and cobalt(II) complexes of 1,4-bis(diphenylphosphinoyl)butaneACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009Anthony M. J. Lees The title complexes, catena -poly[[[diaquadiethanolmanganese(II)]-,-1,4-bis(diphenylphosphinoyl)butane-,2O:O,] dinitrate 1,4-bis(diphenylphosphinoyl)butane solvate], {[Mn(C2H6O)2(C28H28O2P2)(H2O)2](NO3)2·C28H28O2P2}n, (I), and catena -poly[[[diaquadiethanolcobalt(II)]-,-1,4-bis(diphenylphosphinoyl)butane-,2O:O,] dinitrate 1,4-bis(diphenylphosphinoyl)butane solvate], {[Co(C2H6O)2(C28H28O2P2)(H2O)2](NO3)2·C28H28O2P2}n, (II), are isostructural and centrosymmetric, with the MII ions at centres of inversion. The coordination geometry is octahedral, with each metal ion coordinated by two trans ethanol molecules, two trans water molecules and two bridging 1,4-bis(diphenylphosphinoyl)butane ligands which link the coordination centres to form one-dimensional polymeric chains. Parallel chains are linked by hydrogen bonds to uncoordinated 1,4-bis(diphenylphosphinoyl)butane molecules, which are bisected by a centre of inversion. Further hydrogen bonds, weak C,H...O interactions to nitrate anions, and weak C,H..., interactions serve to stabilize the structure. This study reports a development of the coordination chemistry of bis(diphenylphosphinoyl)alkanes, with the first reported structures of complexes of the first-row transition metals with 1,4-bis(diphenylphosphinoyl)butane. [source] 2,3-Dihydro-1,3-benzothiazol-2-iminium hydrogen oxydiacetate: a combined structural and theoretical studyACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009Agata Trzesowska-Kruszynska In the title compound, C7H7N2S+·C4H5O5,, the ions are connected by N,H...O hydrogen bonds. The hydrogen oxydiacetate residues are linked together by O,H...O hydrogen bonds disordered about centres of inversion into hydrogen-bonded ribbon layers crosslinked by weak C,H...O and stacking interactions. The cation exists mainly in the 2,3-dihydro-1,3-benzothiazol-2-iminium form, with a small participation of the 2-aminobenzothiazolium form, based on the structural data and quantum mechanical calculations. This study provides structural insights relevant to the biochemical activity of benzothiazole molecules. [source] | ||||||||||