Showing papers in "Acta Crystallographica Section E-structure Reports Online in 2014"
TL;DR: An accurate redetermination of α-dl-methionine provides coordinates for the H atoms, detailed hydrogen-bond geometries and reveals that the side chain is disordered over a major and a minor position.
Abstract: Two forms, α and β, are known for the racemic amino acid dl-methionine, C5H11NO2S. The phase transition between them, taking place around 326 K, is associated with sliding at the central interfaces of the hydrophobic regions in the crystal, leaving the hydrogen-bonding pattern unperturbed. For the high-temperature α phase, only a structure of rather low quality has been available [R factor = 0.118, no H-atom coordinates; Taniguchi et al. (1980). Bull. Chem. Soc. Jpn, 53, 803–804]. We here present accurate structural data for this polymorph [R(F) = 0.049], which are compared with other related amino acid structures with similar properties. We report for the first time that the side chain of this phase has a minor disorder component [occupancy 0.0491 (18)] with a gauche+ rather than a gauche− conformation for the N—C—C—C group. In the crystal of the title compound, N—H⋯O hydrogen bonds link the molecules into (100) sheets.
19 citations
TL;DR: In the asymmetric unit of the title molecular salt, C6H9N2 +·C2Cl3O2 −, there are two independent 2-amino-6-methylpyridinium cations and two independent trichloroacetate anions that reveal amine–imine tautomerism.
Abstract: In the asymmetric unit of the title mol-ecular salt, C6H9N2 (+)·C2Cl3O2 (-), there are two independent 2-amino-6-methyl-pyridinium cations and two independent tri-chloro-acetate anions. The pyridine N atom of the 2-amino-6-methyl-pyridine mol-ecule is protonated and the geometries of these cations reveal amine-imine tautomerism. Both protonated 2-amino-6-methyl-pyridinium cations are essentially planar [maximum deviations = 0.026 (2) and 0.012 (2) A]. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds, forming an R 2 (2)(8) ring motif. These motifs are connected via N-H⋯O and C-H⋯O hydrogen bonds to form slabs parallel to (101).
16 citations
TL;DR: The crystal grown represents a new monoclinic polymorph in the space group P21/n, which is very similar to that of the orthorhombic polymorph (space group Fdd2) studied previously.
Abstract: In an attempt to grow 8-hydroxyquinoline–acetaminophen co-crystals from equimolar amounts of conformers in a chloroform–ethanol solvent mixture at room temperature, the title compound, C9H7NO, was obtained. The molecule is planar, with the hydroxy H atom forming an intramolecular O—H⋯N hydrogen bond. In the crystal, molecules form centrosymmetric dimers via two O—H⋯N hydrogen bonds. Thus, the hydroxy H atoms are involved in bifurcated O—H⋯N hydrogen bonds, leading to the formation of a central planar four-membered N2H2 ring. The dimers are bound by intermolecular π–π stacking [the shortest C⋯C distance is 3.2997 (17) A] and C—H⋯π interactions into a three-dimensional framework. The crystal grown represents a new monoclinic polymorph in the space group P21/n. The molecular structure of the present monoclinic polymorph is very similar to that of the orthorhombic polymorph (space group Fdd2) studied previously [Roychowdhury et al. (1978). Acta Cryst. B34, 1047–1048; Banerjee & Saha (1986). Acta Cryst. C42, 1408–1411]. The structures of the two polymorphs are distinguished by the different geometries of the hydrogen-bonded dimers, which in the crystal of the orthorhombic polymorph possess twofold axis symmetry, with the central N2H2 ring adopting a butterfly conformation.
14 citations
TL;DR: In the mononuclear title complex, [HgCl2(C20H21N3)], synthesized from the quinoline-derived Schiff base N 1,N 1-diethyl-N 4-(quinolin-2-ylmethylidene)benzene-1,4-diamine (QMBD), the coordination geometry around the Hg2+ atom is distorted tetrahedral.
Abstract: In the mononuclear title complex, [HgCl2(C20H21N3)], synthesized from the quinoline-derived Schiff base N1,N1-diethyl-N4-(quinolin-2-ylmethylidene)benzene-1,4-diamine (QMBD), the coordination geometry around the Hg2+ atom is distorted tetrahedral, comprising two Cl atoms [Hg—Cl = 2.3654 (19) and 2.4394 (18) A] and two N-atom donors from the QMBD ligand, viz. one imine and quinoline [Hg—N = 2.334 (5) and 2.340 (5) A, respectively]. In the crystal, weak C—H⋯Cl hydrogen bonds and weak π–π aromatic ring stacking interactions [minimum ring-centroid separation = 3.680 (4) A] give an overall three-dimensional network.
14 citations
TL;DR: The molecule of the title compound, C18H13NOS, is build up from two fused six-membered rings, with the heterocyclic component linked to a benzylidene group and to a prop-2-yn-1-yl chain that adopts a distorted screw-boat conformation.
Abstract: The molecule of the title compound, C18H13NOS, is build up from two fused six-membered rings, with the heterocyclic component linked to a benzylidene group and to a prop-2-yn-1-yl chain. The six-membered heterocycle adopts a distorted screw-boat conformation. The prop-2-yn-1-yl chain is almost perpendicular to the mean plane through benzothiazine as indicated by the C—N—C—C torsion angle of 86.5 (2)°. The dihedral angle between the benzene rings is 47.53 (12)°. There are no specific intermolecular interactions in the crystal packing.
14 citations
TL;DR: By refining positional coordinates for the three amino H atoms of a previously published amino acid structure, an improved structural model with shorter and more linear hydrogen bonds is obtained.
Abstract: Diffraction data were taken from the contribution named `β-dl-Methionine at 105 K′ by Alagar et al. [Acta Cryst. (2005). E61, o1165–o1167]. Refinement of the coordinates of the three amino H atoms, previously constrained to an idealized geometry, shows that the amino group is in fact rotated 13.5° from the perfectly staggered orientation. This apparently modest change has a profound impact on the calculated hydrogen-bond geometries.
14 citations
TL;DR: In the cation of the title molecular salt, C5H6N3O2 +·C2HO4 −, the dihedral angle between the aromatic ring and the nitro group is 3.5 (3)°; in the anion,The dihedral angles between the CO2 and CO2H planes are 10.5(2)°, and the structure is consolidated by C—H⋯O interactions.
Abstract: In the cation of the title molecular salt, C5H6N3O2+·C2HO4−, the dihedral angle between the aromatic ring and the nitro group is 35 (3)°; in the anion, the dihedral angle between the CO2 and CO2H planes is 105 (2)° In the crystal, the anions are linked into [100] chains by O—H⋯O hydrogen bonds The cations cross-link the chains by way of N—H⋯O hydrogen bonds and the structure is consolidated by C—H⋯O interactions
13 citations
[...]
TL;DR: Single-crystals of the title compound, nonapotassium triyttrium dodecasilicate difluoride, were obtained from flux synthesis experiments in the system SiO2—Y2O3—KF and belong to the group of single-layer silicates and is based on silicate sheets parallel to (110).
Abstract: Single-crystals of the title compound, nonapotassium triyttrium dodecasilicate difluoride, were obtained from flux synthesis experiments in the system SiO2—Y2O3—KF. The crystal structure belongs to the group of single-layer silicates and is based on silicate sheets parallel to (110). A single layer contains secondary (Q2) and tertiary (Q3) silicate tetrahedra in the ratio 1:2 and is build up from six-, eight- and twelve-membered rings. The linkage between neighboring layers is achieved by two crystallographically independent Y3+ cations, which are coordinated by six oxygen ligands in form of distorted octahedra. Charge compensation is accomplished by incorporation of additional F− anions and K+ cations in the structural channels, forming anion-centred [F2K7] groups. Apart from one K+ and one Y3+ cation (each with site symmetry -1), the 30 crystallographically independent atoms reside on general positions.
12 citations
TL;DR: In the mononuclear title complex, [HgCl2(C16H12N2O)], synthesized from the phenolic Schiff base 4-[(quinolin-2-ylmethylidene)amino]phenol (QMAP), the coordination geometry around Hg2+ is distorted tetrahedral, comprising two Cl atoms and two N-atom donors from the QMAP ligand.
Abstract: In the mononuclear title complex, [HgCl2(C16H12N2O)], synthesized from the phenolic Schiff base 4-[(quinolin-2-ylmethylidene)amino]phenol (QMAP), the coordination geometry around Hg2+ is distorted tetrahedral, comprising two Cl atoms [Hg—Cl = 2.3565 (12) and 2.5219 (12) A] and two N-atom donors from the QMAP ligand, viz. one imine and the other quinoline [Hg—N = 2.392 (2) and 2.237 (2) A, respectively]. In the crystal, O—H⋯Cl hydrogen bonds generate a chain structure extending along the c-axis direction. Weak C—H⋯Cl and π–π stacking interactions [minimum ring centroid separation = 3.641 (3) A] give an overall layered structure lying parallel to (001).
12 citations
TL;DR: The asymmetric unit of the title compound, C19H23FN3O3+·Cl−·2H2O [systematic name: 4-(3-carb-oxy-1-cyclo-propyl-6-fluoro-4-oxo-1,4-di-hydro-quin-o-lin-7-yl)-1-ethyl-piperazin-1 -ium chloride dihydrate], consists of two independent monocations of the protonated enrofloxacin, two chloride anions and four
Abstract: The asymmetric unit of the title compound, C19H23FN3O3+·Cl−·2H2O [systematic name: 4-(3-carboxy-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinolin-7-yl)-1-ethylpiperazin-1-ium chloride dihydrate], consists of two independent monocations of the protonated enrofloxacin, two chloride anions and four water molecules. In the cations, the piperazinium rings adopt chair conformations and the dihedral angles between the cyclopropyl ring and the 10-membered quinoline ring system are 56.55 (2) and 51.11 (2)°. An intramolecular O—H⋯O hydrogen bond is observed in each cation. In the crystal, the components are connected via O—H⋯Cl, N—H⋯Cl and O—H⋯O hydrogen bonds, and a π–π interaction between the benzene rings [centroid–centroid distance = 3.6726 (13) A], resulting in a three-dimensional array.
12 citations
TL;DR: The asymmetric unit of the title organic–inorganic molecular salt, C6H18N2 2+·SiF6 2−, consists of one anion and one cation together with half of each of two cations and two anions located on inversion centres.
Abstract: Departement de Physique-Chimie, Laboratoire de Chimie, Centre Regional des Metiers de l’Education et de la Formation, Souissi Rabat, Morocco, Equipe de Physico-Chimie des Materiaux Inorganiques, Universite Ibn Tofail, Faculte des Sciences, BP 133, 14000 Kenitra, Morocco, and Laboratoire de Chimie du Solide Appliquee, Faculte des Sciences, Universite Mohammed V-Agdal, Avenue Ibn Battouta, BP 1014, Rabat, Morocco Correspondence e-mail: a_ouasri@yahoo.fr
TL;DR: The title compound, C20H28O3, is a diterpene lactone which was isolated from Trichoderma asperellum and has a tetracycic 6–5–7–5 ring system, with the cyclohexanone ring adopting a twisted half-chair conformation.
Abstract: The title compound, C20H28O3, known as `trichodermaerin' [systematic name: (4E)-4,9,15,16,16-pentamethyl-6-oxatetracyclo[10.3.1.01,10.05,9]hexadec-4-ene-7,13-dione], is a diterpene lactone which was isolated from Trichoderma asperellum. The structure has a tetracycic 6–5–7–5 ring system, with the cyclohexanone ring adopting a twisted half-chair conformation and the cyclopentane ring adopting a half-chair conformation, whereas the cycloheptene and tetrahydrofurananone rings are in chair and envelope (with the methyl-substituted C atom as the flap) conformations, respectively. The three-dimensional architecture is stabilized by C—H⋯O interactions.
TL;DR: The crystal structure of the title compound, hexaaquadichloridoeuropium(III) chloride, was redetermined with modern crystallographic methods and it was possible to freely refine the positions of the H atoms and thus to improve the accurracy of the crystal structure.
Abstract: The crystal structure of the title compound, hexaaquadichloridoeuropium(III) chloride, was redetermined with modern crystallographic methods. In comparison with the previous study [Lepert et al. (1983). Aust. J. Chem. 36, 477–482], it could be shown that the atomic coordinates of some O atoms had been confused and now were corrected. Moreover, it was possible to freely refine the positions of the H atoms and thus to improve the accurracy of the crystal structure. [EuCl2(H2O)6]Cl crystallizes with the GdCl3·6H2O structure-type, exhibiting discrete [EuCl2(H2O)6]+ cations as the main building blocks. The main blocks are linked with isolated chloride anions via O—H⋯Cl hydrogen bonds into a three-dimensional framework. The Eu3+ cation is located on a twofold rotation axis and is coordinated in the form of a Cl2O6 square antiprism. One chloride anion coordinates directly to Eu3+, whereas the other chloride anion, situated on a twofold rotation axis, is hydrogen bonded to six octahedrally arranged water molecules.
TL;DR: The asymmetric unit of the title salt, C8H14N2 2+·2NO3 −, contains two independent dications and four independent nitrate anions, which consist of discrete nitrate ions that stack in layers parallel to (001) at z = 0 and 0.5.
Abstract: The asymmetric unit of the title salt, C8H14N22+·2NO3−, contains two independent dications and four independent nitrate anions. The crystal structure consists of discrete nitrate ions, three of which stack in layers parallel to (001) at z = 0 and 0.5. These layers are connected via m-xylylenediaminium dications. The fourth anion is sandwiched by the two independent organic cations in the asymmetric unit. In the crystal, the ions are connected by a large number of bifurcated and non-bifurcated N—H⋯O(O) hydrogen bonds, forming sheets parallel to (100). These sheets are connected by C—H⋯O hydrogen bonds, forming a three-dimensional network.
TL;DR: The six-membered thiazine ring in the title compound, C16H15NOS, adopts a half-chair conformation, with the S atom forming the back of the chair with a slight twist reflected in the r.m.s. deviation of those five atoms from the plane defined by them.
Abstract: The six-membered thiazine ring in the title compound, C16H15NOS, adopts a half-chair conformation, with the S atom forming the back of the chair. The base of the chair has a slight twist reflected in the r.m.s. deviation (0.0756 A) of those five atoms from the plane defined by them. The phenyl substituents are almost perpendicular to each other [dihedral angle 87.06 (9)°]. In the crystal, molecules are linked into chains parallel to the c axis through C—H⋯O interactions.
TL;DR: By careful analysis of the structure, it is established that the non-linking cage C atom is equally disordered over cage vertices 2 and 3.
Abstract: In the title compound, C4H22B20, the two {1,2-closo-C2B10H11} cages are linked across a centre of inversion with a C—C distance of 1.5339 (11) A. By careful analysis of the structure, it is established that the non-linking cage C atom is equally disordered over cage vertices 2 and 3.
TL;DR: In the title compound, C18H17ClO, the dihedral angle between the benzene rings is 53 (1)°, and the mean plane of the prop-2-en-1-one group is twisted by 24.5”(8)°.
Abstract: In the title compound, C18H17ClO, the dihedral angle between the benzene rings is 53.5 (1)°. The mean plane of the prop-2-en-1-one group is twisted by 24.5 (8) and 33.5 (3)° from the chloro- and propanyl-substituted rings, respectively.
TL;DR: The title compound, tetrasodium cobalt(II) tris[molybdate(IV)], was prepared by solid-state reactions and is isotypic with Na3In2(AsO4)3 and Na3 in2(PO4) 3, forming a three-dimensional framework enclosing two types of hexagonal tunnels in which Na+ cations reside.
Abstract: The title compound, tetrasodium cobalt(II) tris[molybdate(IV)], was prepared by solid-state reactions. The structure is isotypic with Na3In2(AsO4)3 and Na3In2(PO4)3. The main structural feature is the presence of infinite chains of edge-sharing X2O10 (X = Co/Na) dimers, which are linked by MoO4 tetrahedra, forming a three-dimensional framework enclosing two types of hexagonal tunnels in which Na+ cations reside. In this alluaudite structure, Co and Na atoms are located at the same general site with occupancies of 0.503 (5) and 0.497 (6), respectively. The other three Na and one of the two Mo atoms lie on special positions (site symmetries 2, -1, 2 and 2, respectively). The structure is compared with similar structures and other members of alluaudite family.
TL;DR: The crystal structures of the tri-, tetra- and nonahydrate phases of Sr(ClO4)2 consist of Sr2+ ions coordinated by nine oxygen atoms from water molecules and perchlorate tetrahedra that lead to the formation of a three-dimensional network in each of the structures.
Abstract: The title compounds, strontium perchlorate trihydrate {di-μ-aqua-aquadi-μ-perchlorato-strontium, [Sr(ClO4)2(H2O)3]n}, strontium perchlorate tetrahydrate {di-μ-aqua-bis(triaquadiperchloratostrontium), [Sr2(ClO4)4(H2O)8]} and strontium perchlorate nonahydrate {heptaaquadiperchloratostrontium dihydrate, [Sr(ClO4)2(H2O)7]·2H2O}, were crystallized at low temperatures according to the solid–liquid phase diagram The structures of the tri- and tetrahydrate consist of Sr2+ cations coordinated by five water molecules and four O atoms of four perchlorate tetrahedra in a distorted tricapped trigonal–prismatic coordination mode The asymmetric unit of the trihydrate contains two formula units Two [SrO9] polyhedra in the trihydrate are connected by sharing water molecules and thus forming chains parallel to [100] In the tetrahydrate, dimers of two [SrO9] polyhedra connected by two sharing water molecules are formed The structure of the nonahydrate contains one Sr2+ cation coordinated by seven water molecules and by two O atoms of two perchlorate tetrahedra (point group symmetry m), forming a tricapped trigonal prism (point group symmetry m2m) The structure contains additional non-coordinating water molecules, which are located on twofold rotation axes O—H⋯O hydrogen bonds between the water molecules as donor and ClO4 tetrahedra and water molecules as acceptor groups lead to the formation of a three-dimensional network in each of the three structures
TL;DR: In the crystal, the molecules form a layered structure parallel to (10) via C—H⋯O hydrogen-bonding interactions, forming a three-dimensional structure.
Abstract: The title compound, C26H20O5, crystallizes with two independent molecules (A and B) in the asymmetric unit, which differ primarily in the location of the –OCH3 groups. In the crystal, the molecules form a layered structure parallel to (10-1) by C—H⋯O hydrogen-bonded networks. Adjacent layers are also linked by further C—H⋯O hydrogen bonds, forming a three-dimensional structure.
TL;DR: In the title hydrate, (C4H12N2)[Co{B6O7(OH)6}2]·6H2O, both the dication and dianion are generated by crystallographic inversion symmetry.
Abstract: In the title hydrate, (C4H12N2)[Co{B6O7(OH)6}2]·6H2O, both the dication and dianion are generated by crystallographic inversion symmetry. The Co2+ ion in the dianion adopts a fairly regular CoO6 octahedral coordination geometry arising from the two O,O′,O′′-tridentate ligands. In the crystal, the dianions and water molecules are linked by O—H⋯O hydrogen bonds, generating a framework with large [100] channels, which are occupied by the organic dications. N—H⋯O and C—H⋯O hydrogen bonds consolidate the structure.
TL;DR: The crystal structures of the 1.5- and 10-hydrates of Na2SeO4 are isotypic with those of the corresponding chromates.
Abstract: The crystal structures of Na2SeO4·1.5H2O (sodium selenate sesquihydrate) and Na2SeO4·10H2O (sodium selenate decahydrate) are isotypic with those of Na2CrO4·1.5H2O and Na2XSeO4·10H2O (X = S, Cr), respectively. The asymmetric unit of the sesquihydrate contains two Na+ cations, one SeO4 tetrahedron and one and a half water molecules, the other half being generated by twofold rotation symmetry. The coordination polyhedra of the cations are a distorted monocapped octahedron and a square pyramid; these [NaOx] polyhedra are linked through common edges and corners into a three-dimensional framework structure, the voids of which are filled with the Se atoms of the SeO4 tetrahedra. The structure is consolidated by O—H⋯O hydrogen bonds between coordinating water molecules and framework O atoms. The asymmetric unit of the decahydrate consists of two Na+ cations, one SeO4 tetrahedron and ten water molecules. Both Na+ cations are octahedrally surrounded by water molecules and by edge-sharing condensed into zigzag chains extending parallel to [001]. The SeO4 tetrahedra and two uncoordinating water molecules are situated between the chains and are connected to the chains through an intricate network of medium-strength O—H⋯O hydrogen bonds.
TL;DR: In the title compound, C10H4Br2O3, the atoms of the 6,8-dibromochromone unit are essentially coplanar [largest deviation from the mean planes = 0.1109 (3) Å]; the formyl group is twisted slightly with respect to the attached ring.
Abstract: In the title compound, C10H4Br2O3, the atoms of the 6,8-dibromochromone unit are essentially coplanar [largest deviation from the mean planes = 0.1109 (3) A] and the formyl group is twisted slightly with respect to the attached ring [C—C—C—O torsion angles = 11.5 (4) and −168.9 (3)°]. In the crystal, molecules are linked to each other through halogen bonds [Br⋯O = 3.118 (2) A, C—Br⋯O = 162.37 (8) and C=O⋯Br = 140.20 (15)°]. The molecules are further assembled via π–π stacking interactions [centroid–centroid distance = 3.850 (2) A].
TL;DR: A difluoro-substitution of the organic cation demonstrates the structural versatility of the new approach to bicyclic aromatic benzimidazolium cation stabilizes the layered perovskite structure comprising inorganic {[SnI4]2−}n sheets.
Abstract: The isostructural title compounds, {(C7H7N2)2[SnI4]}n, (1), and {(C7H5F2N2)2[SnI4]}n, (2), show a layered perovskite-type structure composed of anionic {[SnI4]2−}n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-difluorobenzimidazolium cations, respectively. These planar organic heterocycles mainly form N—H⋯I hydrogen bonds to the terminal I atoms of the corner-sharing [SnI6] octahedra (point group symmetry 2) from the inorganic layer, but not to the bridging ones. This is in contrast to most of the reported structures of related compounds where ammonium cations are involved. Here hydrogen bonding to both types of iodine atoms and thereby a distortion of the inorganic layers to various extents is observed. For (1) and (2), all Sn—I—Sn angles are linear and no out-of-plane distortions of the inorganic layers occur, a fact of relevance in view of the material properties. The arrangement of the aromatic cations is mainly determined through the direction of the N—H⋯I hydrogen bonds. The coherence between organic bilayers along [100] is mainly achieved through van der Waals interactions.
TL;DR: In the structure of the title salt, C6H16N2 2+·2NO3 −, the cations are connected to the anions through bifurcated N—H⋯(O,O) and weak C—H ⋯O hydrogen bonds, generating corrugated layers parallel to the (100) plane.
Abstract: In the structure of the title salt, C6H16N2 (2+)·2NO3 (-), the cations are connected to the anions through bifurcated N-H⋯(O,O) and weak C-H⋯O hydrogen bonds, generating corrugated layers parallel to the (100) plane. The organic cation is centrosymmetric and the diprotonated piperazine ring adopts a chair conformation, with the methyl groups occupying equatorial positions.
TL;DR: The structures of ammonium salts of phenoxy-acetic acid, NH4+·C8H6O3−, (I), (4-fluoro-phenoxy) acetic acid (MCPA), NH4·C9H8ClO3 −·0.5H2O, (III) have been determined as mentioned in this paper.
Abstract: The structures of the ammonium salts of phenoxyacetic acid, NH4+·C8H6O3−, (I), (4-fluorophenoxy)acetic acid, NH4+·C8H5FO3−, (II), and the herbicidally active (4-chloro-2-methylphenoxy)acetic acid (MCPA), NH4+·C9H8ClO3−·0.5H2O, (III) have been determined. All have two-dimensional layered structures based on inter-species ammonium N—H⋯O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I) and (II) are isomorphous with the core comprising R12(5), R12(4) and centrosymmetric R42(8) ring motifs, giving two-dimensional layers lying parallel to (100). In (III), the water molecule of solvation lies on a crystallographic twofold rotation axis and bridges two carboxyl O atoms in an R44(12) hydrogen-bonded motif, creating two R43(10) rings, which together with a conjoined centrosymmetric R42(8) ring incorporating both ammonium cations, generate two-dimensional layers lying parallel to (100). No π–π ring associations are present in any of the structures.
TL;DR: In the title salt, [(CH3CH2CH2)2NH2]4[Sn(C2O4)4]·H2O, the SnIV atom of the stannate anion is located on a special position with -42m symmetry.
Abstract: In the title salt, [(CH3CH2CH2)2NH2]4[Sn(C2O4)4]·H2O, the SnIV atom of the stannate anion is located on a special position with -42m symmetry. It is eight-coordinated by four chelating oxalate anions. The dipropylammonium cation possesses mirror symmetry while the lattice water molecule is disordered about a position with -42m symmetry and has an occupancy of 0.25. In the crystal, the anions and cations are linked by N—H⋯O hydrogen bonds, forming a three-dimensional network. This network is futher stabilized by weak O—H⋯O hydrogen bonds involving the water molecules and oxalate O atoms. The crystal studied was refined as an inversion twin.
TL;DR: The title compounds, (I) and (II), are dispiro-indole-pyrrolidine-benzothiophene derivatives, with (II) having a chlorine substituent on the oxoindole unit.
Abstract: In the title compounds, C22H20N2O4S, (I), and C22H19ClN2O4S, (II), the pyrrolidine rings have twist conformations on the spiro–spiro C—C bonds. In (I), the five-membered ring of the oxindole moiety has an envelope conformation with the spiro C atom as the flap, while in (II) this ring is flat (r.m.s. deviation = 0.042 A). The mean planes of the pyrrolidine rings are inclined to the mean planes of the indole units [r.m.s deviations = 0.073 and 0.069 A for (I) and (II), respectively] and the benzothiophene ring systems (r.m.s. deviations = 0.019 and 0.034 A for (I) and (II), respectively) by 79.57 (8) and 88.61 (7)° for (I), and by 81.99 (10) and 88.79 (10)° for (II). In both compounds, the ethoxycarbonyl group occupies an equatorial position with an extended conformation. The overall conformation of the two molecules differs in the angle of inclination of the indole unit with respect to the benzothiophene ring system, with a dihedral angle between the planes of 71.59 (5) in (I) and 82.27 (7)° in (II). In the crystal of (I), molecules are linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers enclosing R22(14) loops. The dimers are linked via C—H⋯O and bifurcated C—H⋯O(O) hydrogen bonds, forming sheets lying parallel to (100). In the crystal of (II), molecules are again linked via pairs of N—H⋯O hydrogen bonds, forming inversion dimers but enclosing smaller R22(8) loops. Here, the dimers are linked by C—H⋯O hydrogen bonds, forming ribbons propagating along [010].
TL;DR: The crystal structures of ZnCl2·xH2O (x = 2.5, 3 and 4) consist ofZn2+ ions both in an octahedral and tetrahedral environment, which lead to the formation of a three-dimensional network in each of the structures.
Abstract: The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetrahedral coordination with Cl− and in an octahedral environment defined by five water molecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O)5] (pentaaqua-μ-chlorido-trichloridodizinc). The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O)6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetrahedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O)6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O)6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O)6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H⋯O hydrogen bonds between the water molecules as donor and ZnCl4 tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.
TL;DR: The title compound, [NH3(CH2)4NH3]2+·SiF62−, is a hybrid built from an organic butane-1,4-di-ammonium dication linked to a hexa-fluoro-silicate mineral anion as discussed by the authors.
Abstract: The title compound, [NH3(CH2)4NH3]2+·SiF62−, is a hybrid built from an organic butane-1,4-diammonium dication linked to a hexafluorosilicate mineral anion. Both ions posses inversion symmetry. In the anion the Si atom is located on an inversion center, while in the cation the center of inversion is situated at the mid-point of the central —CH2—CH2— bond. The Si atom is surrounded by six F atoms, forming a slightly distorted SiF62− octahedron. These octahedra are linked to the organic cations through N—H⋯F hydrogen bonds, forming a three-dimensional network.