Showing papers in "Acta Crystallographica Section E: Crystallographic Communications in 2017"
TL;DR: Crystal structure, thermal behaviour and phase transitions of formamidinium iodide were studied by DTG, DSC, powder diffraction and X-ray crystallography.
Abstract: At a temperature of 100 K, CH5N2+·I− (I), crystallizes in the monoclinic space group P21/c. The formamidinium cation adopts a planar symmetrical structure [the r.m.s. deviation is 0.002 A, and the C—N bond lengths are 1.301 (7) and 1.309 (8) A]. The iodide anion does not lie within the cation plane, but deviates from it by 0.643 (10) A. The cation and anion of I form a tight ionic pair by a strong N—H⋯I hydrogen bond. In the crystal of I, the tight ionic pairs form hydrogen-bonded zigzag-like chains propagating toward [20-1] via strong N—H⋯I hydrogen bonds. The hydrogen-bonded chains are further packed in stacks along [100]. The thermal behaviour of I was studied by different physicochemical methods (thermogravimetry, differential scanning calorimetry and powder diffraction). Differential scanning calorimetry revealed three narrow endothermic peaks at 346, 387 and 525 K, and one broad endothermic peak at ∼605 K. The first and second peaks are related to solid–solid phase transitions, while the third and fourth peaks are attributed to the melting and decomposition of I. The enthalpies of the phase transitions at 346 and 387 K are estimated as 2.60 and 2.75 kJ mol−1, respectively. The X-ray powder diffraction data collected at different temperatures indicate the existence of I as the monoclinic (100–346 K), orthorhombic (346–387 K) and cubic (387–525 K) polymorphic modifications.
32 citations
TL;DR: In the title compound, the toluenesulfonamide ring and the combined ring system involving the pyridone and benzothiazole rings subtend an interplanar angle of 39.86 (4)°.
Abstract: In the title compound, C21H17N5O3S3·C3H7NO, the toluenesulfonamide ring and the combined ring system involving the pyridone and benzothiazole rings subtend an interplanar angle of 39.86 (4)°. The pyridone and benzothiazyl rings are linked by the intramolecular hydrogen bond N—Hamine⋯Nthiazole. The DMF O atom accepts two classical hydrogen bonds. The molecules are linked by hydrogen bonds and an S⋯O contact to form layers parallel to the bc plane.
20 citations
TL;DR: In the title compound, C16H15N3O3S2, the hydrazide N atom bonded to the C=O group is planar, whereas that bonded to SO2 group is pyramidally coordinated.
Abstract: In the title compound, C16H15N3O3S2, the hydrazide N atom bonded to the C=O group is planar, whereas that bonded to the SO2 group is pyramidally coordinated. The interplanar angle between the ring systems is 40.71 (3)°. Molecules are connected into ribbons parallel to the b axis by two classical hydrogen bonds N—H⋯O=C and N—H⋯Nthiazole.
17 citations
TL;DR: The syntheses and crystal structures of 3-chloro-3-methyl-r-2,c-6-diphenylpiperidin-4-one and two of its derivatives are described and the piperidine ring adopts a chair conformation.
Abstract: The syntheses and crystal structure of 3-chloro-3-methyl-r-2,c-6-diphenylpiperidin-4-one, C18H18ClNO, (I), 3-chloro-3-methyl-r-2,c-6-di-p-tolylpiperidin-4-one, C20H22ClNO, (II), and 3-chloro-3-methyl-r-2,c-6-bis(4-chlorophenyl)piperidin-4-one, C18H16Cl3NO, (III), are described. In each structure, the piperidine ring adopts a chair conformation and dihedral angles between the mean planes of the phenyl rings are 58.4 (2), 73.5 (5) and 78.6 (2)° in (I), (II) and (III), respectively. In the crystals, molecules are linked into C(6) chains by weak N—H⋯O hydrogen bonds and C—H⋯π interactions are also observed.
13 citations
TL;DR: Two molecules comprise the asymmetric unit in the title thioamide molecule, each of which exists as theThioamide–thione tautomer, and in the crystal, the molecules assemble via an eight-membered thioamide synthon to form dimeric aggregates.
Abstract: The title compound, C10H13NOS, is a second monoclinic polymorph (space group P21/c, Z′ = 2) of the previously reported C2/c (Z = 1) polymorph [Tadbuppa & Tiekink (2005). Z. Kristallogr. New Cryst. Struct. 220, 395–396]. Two independent molecules comprise the asymmetric unit of the new polymorph and each of these exists as a thioamide–thione tautomer. In each molecule, the central CNOS chromophore is strictly planar [r.m.s. deviations = 0.0003 and 0.0015 A] and forms dihedral angles of 6.17 (5) and 20.78 (5)° with the N-bound 3-tolyl rings, thereby representing the major difference between the molecules. The thione-S and thioamide-N—H atoms are syn in each molecule and this facilitates the formation of an eight-membered thioamide {⋯SCNH}2 synthon between them; the dimeric aggregates are consolidated by pairwise 3-tolyl-C—H⋯S interactions. In the extended structure, supramolecular layers parallel to (102) are formed via a combination of 3-tolyl-C—H⋯π(3-tolyl) and weak π–π interactions [inter-centroid distance between 3-tolyl rings = 3.8535 (12) A]. An analysis of the Hirshfeld surfaces calculated for both polymorphs reveals the near equivalence of one of the independent molecules of the P21/c form to that in the C2/c form.
12 citations
TL;DR: A skew trapezoidal bipyramidal coordination geometry based on a C2S4 donor set is found in the structure of (C6H5)2Sn[S2CN(Me)CH2CH2OMe]2, with the SnIV atom lying on a mirror plane.
Abstract: The complete molecule of the title compound, [Sn(C4H9)2(C5H10NOS2)2], is generated by a crystallographic mirror plane, with the SnIV atom and the two inner methylene C atoms of the butyl ligands lying on the mirror plane; statistical disorder is noted in the two terminal ethyl groups, which deviate from mirror symmetry. The dithiocarbamate ligand coordinates to the metal atom in an asymmetric mode with the resulting C2S4 donor set defining a skew trapezoidal bipyramidal geometry; the n-butyl groups are disposed to lie over the longer Sn—S bonds. Supramolecular chains aligned along the a-axis direction and sustained by methylene-C—H⋯S(weakly coordinating) interactions feature in the molecular packing. A Hirshfeld surface analysis reveals the dominance of H⋯H contacts in the crystal.
11 citations
TL;DR: The isolation and crystal structures of the title compounds from Hibiscus sabdariffa (Malvaceae) are described and it is shown that hibiscus acid dimethyl sulfoxide monosolvate forms a two-dimensional hydrogen-bonded motif.
Abstract: The biologically active title compounds have been isolated from Hibiscus sabdariffa plants, hibiscus acid as a dimethyl sulfoxide monosolvate [systematic name: (2S,3R)-3-hydroxy-5-oxo-2,3,4,5-tetrahydrofuran-2,3-dicarboxylic acid dimethyl sulfoxide monosolvate], C6H6O7·C2H6OS, (I), and hibiscus acid dimethyl ester [systematic name: dimethyl (2S,3R)-3-hydroxy-5-oxo-2,3,4,5-tetrahydrofuran-2,3-dicarboxylate], C8H10O7, (II). Compound (I) forms a layered structure with alternating layers of lactone and solvent molecules, that include a two-dimensional hydrogen-bonding construct. Compound (II) has two crystallographically independent and conformationally similar molecules per asymmetric unit and forms a one-dimensional hydrogen-bonding construct. The known absolute configuration for both compounds has been confirmed.
11 citations
TL;DR: New data show that dimethyl sulfoxide molecule approximates C s symmetry in the solid state where all atoms occupy general positions.
Abstract: The title compound, C2H6OS, is a high melting, polar and aprotic solvent widely used in organic and inorganic chemistry. It serves as a H-atom acceptor in hydrogen bonding and is used as an ambidentate ligand in coordination chemistry. The evaluation of the influence of intermolecular interactions on the internal structural parameters of the chemically bonded DMSO molecules affords precise structural data of the free molecule as a point of reference. So far, valid data have been obtained only by use of neutron powder diffraction [Ibberson (2005). Acta Cryst. C61, o571–o573]. In the present redetermination, structural data have been obtained from a single-crystal X-ray diffraction experiment at 100 K, revealing a better comparison with DMSO molecules in other crystal structures. In the solid state, the pyramidal molecule exhibits a nearly perfect Cs symmetry [including H atoms, which are eclipsed with respect to the C⋯C axis], with a C—S—C bond angle of 97.73 (7)° and an S—O bond length of 1.5040 (10) A, corresponding very well with an S=O double bond, and with almost equal S—C bond lengths [mean value = 1.783 (4) A] and O—S—C bond angles [mean value = 106.57 (4)°]. The crystal packing is influenced by C—H⋯O interactions (2.42–2.47 A) between all three H atoms of only one methyl group with the O atoms of three neighbouring DMSO molecules. The interactions of the O atom with H atoms (or Lewis acids, or hydrogen-donor groups) of adjacent molecules in relation to the orientation of the complete DMSO molecule are described in terms of the angle ω and the distance dnorm; ω is the angle between the pseudo-mirror plane of the molecule and the plane defined through the S=O bond and the interacting atom, and dnorm is the distance of the interacting atom from the plane perpendicular to the S=O bond.
11 citations
TL;DR: In the title compound, the 1,2,3-triazoyl ring is flanked by nitrobenzene and benzyl substituents with the dihedral angle of 70.60 (9)° between rings indicating a twisted l-shape for the molecular conformation.
Abstract: The molecule in the title compound, C15H12N4O2, has a twisted L-shape with the dihedral angle between the aromatic rings of the N-bound benzene and C-bound benzyl groups being 70.60 (9)°. The nitro group is co-planar with the benzene ring to which it is connected [C—C—N—O torsion angle = 0.4 (3)°]. The three-dimensional packing is stabilized by a combination of methylene-C—H⋯O(nitro), methylene-C—H⋯π(phenyl), phenyl-C—H⋯π(triazolyl) and nitro-O⋯π(nitrobenzene) interactions, along with weak π(triazolyl)–π(nitrobenzene) contacts [inter-centroid distance = 3.8386 (10) A]. The importance of the specified intermolecular contacts has been verified by an analysis of the calculated Hirshfeld surface.
11 citations
TL;DR: The molecular structures of two isotypic titanium(III) complexes bearing an trimethylaluminium or -gallium motif are reported, and two methyl groups coordinate to the metal atoms in a μ 2 manner.
Abstract: The isotypic crystal structures of two titanocene complexes containing an EMe3 unit (E = Al, Ga; Me = methyl) with two μ2-coordinating methyl groups, namely [μ-1(η5)-(adamantan-1-yl-2κC1)cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5)-pentamethylcyclopentadienyl]aluminiumtitanium(III), [AlTi(CH3)3(C10H15)(C15H18)], and [μ-1(η5)-(adamantan-1-yl-2κC1)cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5)-pentamethylcyclopentadienyl]galliumtitanium(III), [GaTi(CH3)3(C10H15)(C15H18)], are reported. Reacting a dinuclear nitrogen-bridged low-valent titanium(III) complex with the Lewis acids AlMe3 or GaMe3 results in the loss of molecular dinitrogen and the formation of two monomeric titanocene(III) fragments bearing two μ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a new E—C bond involving the pentafulvene ligand while the bridging and terminal methyl groups remain intact.
10 citations
TL;DR: The title compound, C18H22FN5O8S, is used as a herbicide and has a crystal structure stabilized by N/C—H⋯O hydrogen bond, C—H–F and C–π interactions with weak π-π interactions contacts to form a three-dimensional architecture.
Abstract: The title compound, {systematic name: 1-[3-({[(4,6-dimethoxypyrimidin-2-yl)carbamoyl]amino}sulfonyl)pyridin-2-yl]-2-fluoropropyl 2-methoxyacetate}, C18H22FN5O8S, is used as a herbicide (pyrimidinylsulfonylurea herbicide). The dihedral angle between the mean planes of the pyridine and pyrimidine rings is 86.90 (7)°. In the crystal, N/C—H⋯O hydrogen bonds, C—H⋯F and C—H⋯π interactions link adjacent molecules, forming a chain along [020]. A further two C—H⋯O hydrogen bonds together with weak π–π interactions [ring centroid separation = 3.7584 (12) A] further aggregate the structure into a three-dimensional architecture.
TL;DR: In the title compound, the hydrophilic glucose residues lie in the regions z ≃ ab plane, from which the pyridyl rings project; p Pyridyl ring stacking parallel to the a axis links adjacent layers.
Abstract: In the title compound, C14H18N2O5S, the C—S bond lengths are unequal, with S—Cglucose = 1.8016 (15) A and S—Cpyridyl = 1.7723 (13) A. The hydrophilic glucose residues lie in the regions z ≃ 0.25 and 0.75. Four classical hydrogen bonds link the molecules to form layers parallel to the ab plane, from which the pyridyl rings project; pyridyl ring stacking parallel to the a axis links adjacent layers.
TL;DR: Three compounds have tetrahedral–octahedral framework topologies and, in KIn(HAsO4)2, there is a second K-atom position with a very low occupancy, which may suggest that the K atom can easily move in the channels extending along.
Abstract: Potassium indium bis[hydrogen arsenate(V)], KIn(HAsO4)2, rubidium indium bis[hydrogen arsenate(V)], RbIn(HAsO4)2, and caesium indium bis[hydrogen arsenate(V)], CsIn(HAsO4)2, were grown under mild hydrothermal conditions (T = 493 K, 7–8 d) KIn(HAsO4)2 adopts the KSc(HAsO4)2 structure type (space group C2/c), while RbIn(HAsO4)2 and CsIn(HAsO4)2 crystallize in the space group R-3c and are the first arsenate representatives of the RbFe(HPO4)2 structure type All three compounds have tetrahedral–octahedral framework topologies The M+ cations, located in voids of the respective framework, are slightly disordered in RbIn(HAsO4)2 In KIn(HAsO4)2, there is a second K-atom position with a very low occupancy, which may suggest that the K atom can easily move in the channels extending along [101]
TL;DR: The crystal structure of trirubidium citrate monohydrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques.
Abstract: The crystal structure of the title compound, 3Rb+·C6H5O73-·H2O, has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The hy-droxy group participates in an intra-molecular hydrogen bond to the deprotonated central carboxyl-ate group with graph-set motif S(5). The water mol-ecule acts as a hydrogen-bond donor to both terminal and central carboxyl-ate O atoms. The three independent rubidium cations are seven-, six- and six-coordinate, with bond-valence sums of 0.84, 1.02, and 0.95, respectively. In the extended structure, their polyhedra share edges and corners to form a three-dimensional network. The hydro-phobic methyl-ene groups occupy channels along the b axis.
TL;DR: The crystal structure of pentasodium hydrogen dicitrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques.
Abstract: The crystal structure of pentasodium hydrogen dicitrate, Na5H(C6H5O7)2, has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Each of the two independent citrate anions is joined into a dimer by very strong centrosymmetric O—H⋯O hydrogen bonds, with O⋯O distances of 2.419 and 2.409 A. Four octahedrally coordinated Na+ ions share edges to form open layers parallel to the ab plane. A fifth Na+ ion in trigonal–bipyramidal coordination shares faces with NaO6 octahedra on both sides of these layers.
TL;DR: In the title compound, the hydroxy group forms a intramolecular hydrogen bond to the imine N atom and generates an S(6) ring motif.
Abstract: The title compound, C23H29N3O, was synthesized from the condensation reaction of 8-hydroxyjulolidine-9-carbaldehyde and N,N-diethyl-p-phenylenediamine. The hydroxy group forms a intramolecular hydrogen bond to the imine N atom and generates an S(6) ring motif. The conformation about the C=N bond is E, and the aromatic ring of the julolidine moiety is inclined to the benzene ring by 3.74 (14)°. One of the fused non-aromatic rings of the julolidine moiety adopts an envelope conformation and the other has a screw-boat conformation. In the crystal, molecules are linked by C—H⋯π interactions involving the aromatic julolidine ring, forming slabs parallel to the bc plane. The tricyclic fragment of the julolidine ring and the azomethine C=N bond are disordered over two sets of sites with a refined occupancy ratio of 0.773 (3):0.227 (3).
TL;DR: The complex title molecule lies across an inversion centre and exhibits a slightly distorted octahedral coordination environment for the CoII atom.
Abstract: The title complex, [Co(C7H7N4O2)2(H2O)4], comprises mononuclear molecules consisting of a CoII ion, two deprotonated theophylline ligands (systematic name: 1,3-dimethyl-7H-purine-2,6-dione) and four coordinating water molecules. The CoII atom lies on an inversion centre and has a slightly distorted octahedral coordination environment, with two N atoms of two trans-oriented theophylline ligands and the O atoms of four water molecules. An intramolecular hydrogen bond stabilizes this conformation. A three-dimensional supramolecular network structure is formed by intermolecular O—H⋯O and O—H⋯N hydrogen bonds.
TL;DR: Trisodium rubidium heptamagnesium hexakis(orthophosphate) exhibits a new structure type, with MgOx polyhedra linked directly to each other through common corners or edges and reinforced by corner-sharing with PO4 tetrahedra.
Abstract: A new magnesium phosphate, Na3RbMg7(PO4)6 [trisodium rubidium heptamagnesium hexakis(orthophosphate)], has been synthesized as single crystals by the flux method and exhibits a new structure type. Its original structure is built up from MgOx (x = 5 and 6) polyhedra linked directly to each other through common corners or edges and reinforced by corner-sharing with PO4 tetrahedra. The resulting anionic three-dimensional framework leads to the formation of channels along the [010] direction, in which the Na+ cations are located, while the Rb+ cations are located in large interstitial cavities.
TL;DR: The molecular and crystal structure of the insecticide fipronil is reported and it is reported that there are short F⋯F interactions present.
Abstract: The title compound, C12H4Cl2F6N4OS {systematic name: 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethane)sulfinyl]-1H-pyrazole-3-carbonitrile}, is a member of the phenylpyrazole group of acaricides, and one of the phenylpyrazole group of insecticides. The dihedral angle between the planes of the pyrazole and benzene rings is 89.03 (9)°. The fluorine atoms of the trifluoromethyl substituent on the benzene ring are disordered over two sets of sites, with occupancy ratios 0.620 (15):0.380 (15). In the crystal, C—N⋯π interactions [N⋯ring centroid = 3.607 (4) A] together with N—H⋯N and C—H⋯F hydrogen bonds form a looped chain structure along [10\overline{1}]. Finally, N—H⋯O hydrogen bonds and C—Cl⋯π interactions [Cl⋯ring centroid = 3.5159 (16) A] generate a three-dimensional structure. Additionally, there are a short intermolecular F⋯ F contacts present.
TL;DR: The crystal structure of trirubidium citrate has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques.
Abstract: The crystal structure of trirubidium citrate, 3Rb+·C6H5O73−, has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The two independent Rb+ cations are seven- and eight-coordinate, with bond-valence sums of 0.99 and 0.92 valence units. The coordination polyhedra share edges and corners to form a three-dimensional framework. The only hydrogen bond is an intramolecular one between the hydroxy group and the central carboxylate, with graph set S(5). The hydrophobic methylene groups lie in pockets in the framework.
TL;DR: The transition metal orthophosphate Ag1.655Co1.64Fe1.36(PO4)3 crystallizes in an alluaudite-type structure that consists of chains built up from edge-sharing [CoO6] and [FeO 6] octahedra linked together by PO4 tetrahedra.
Abstract: The new silver-, cobalt- and iron-based phosphate, silver cobalt iron tris(orthophosphate), Ag1.655Co1.64Fe1.36(PO4)3, was synthesized by solid-state reactions. Its structure is isotypic to that of Na2Co2Fe(PO4)3, and belongs to the alluaudite family, with a partial cationic disorder, the AgI atoms being located on an inversion centre and twofold rotation axis sites (Wyckoff positions 4a and 4e), with partial occupancies of 0.885 (2) and 0.7688 (19), respectively. One of the two P atoms in the asymmetric unit completely fills one 4e site while the Co and Fe atoms fill another 4e site, with partial occupancies of 0.86 (5) and 0.14 (5), respectively. The remaining Co2+ and Fe3+ cations are distributed on a general position, 8f, in a 0.39 (4):0.61 (4) ratio. All O atoms and the other P atoms are in general positions. The structure is built up from zigzag chains of edge-sharing [MO6] (M = Fe/Co) octahedra stacked parallel to [101]. These chains are linked together through PO4 tetrahedra, forming polyhedral sheets perpendicular to [010]. The resulting framework displays two types of channels running along [001], in which the AgI atoms (coordination number eight) are located.
TL;DR: The molecule is non-planar and the dihedral angle between the phenyl rings is 50.72 (4)°, so only a weak directional interaction of the C—H⋯O type combines molecules in infinite chains running along the a axis.
Abstract: The structure of the title compound, C23H26O5 or CH2=C(CH3)—C(O)O—C6H4—O(O)C—C6H4—OC6H13, has been determined. The molecule is non-planar and the dihedral angle between the phenyl rings is 50.72 (4)°. The crystal packing differs from those typical for mesogenic compounds. Only a weak directional interaction of the C—H⋯O type combines molecules in endless chains running along the a axis.
TL;DR: P-Arsanilic acid forms an isotypic set of three compounds with the alkali metals K, Rb and Cs, in which the primary layered coordination polymeric structures have similar asymmetric units comprising two independent and different metal cations and a bridging water molecule.
Abstract: The structures of the alkali metal (K, Rb and Cs) complex salts with 4-aminophenylarsonic acid (p-arsanilic acid) manifest an isotypic series with the general formula [M2(C6H7AsNO3)2(H2O)3], with M = K {poly[di-μ3-4-aminophenylarsonato-tri-μ2-aqua-dipotassium], [K2(C6H7AsNO3)2(H2O)3], (I)}, Rb {poly[di-μ3-4-aminophenylarsonato-tri-μ2-aqua-dirubidium], [Rb2(C6H7AsNO3)2(H2O)3], (II)}, and Cs {poly[di-μ3-4-aminophenylarsonato-tri-μ2-aqua-dirubidium], [Cs2(C6H7AsNO3)2(H2O)3], (III)}, in which the repeating structural units lie across crystallographic mirror planes containing two independent and different metal cations and a bridging water molecule, with the two hydrogen p-arsanilate ligands and the second water molecule lying outside the mirror plane. The bonding about the two metal cations in all complexes is similar, one five-coordinate, the other progressing from five-coordinate in (I) to eight-coordinate in both (II) and (III), with overall M—O bond-length ranges of 2.694 (5)–3.009 (7) (K), 2.818 (4)–3.246 (4) (Rb) and 2.961 (9)–3.400 (10) A (Cs). The additional three bonds in (II) and (III) are the result of inter-metal bridging through the water ligands. Two-dimensional coordination polymeric structures with the layers lying parallel to (100) are generated through a number of bridging bonds involving the water molecules (including hydrogen-bonding interactions), as well as through the arsanilate O atoms. These layers are linked across [100] through amine N—H⋯O hydrogen bonds to arsonate and water O-atom acceptors, giving overall three-dimensional network structures.
TL;DR: In the title compound, the epoxide O atom and the 4-methoxyphenyl group lie on opposite sides of the pyrrolidyl ring, whereas the ethyl ester is approximately planar.
Abstract: The title compound, C14H17NO4, features an epoxide-O atom fused to a pyrrolidyl ring, the latter having an envelope conformation with the N atom being the flap. The 4-methoxyphenyl group is orthogonal to [dihedral angle = 85.02 (6)°] and lies to the opposite side of the five-membered ring to the epoxide O atom, while the N-bound ethyl ester group (r.m.s. deviation of the five fitted atoms = 0.0187 A) is twisted with respect to the ring [dihedral angle = 17.23 (9)°]. The most prominent interactions in the crystal are of the type methine-C—H⋯O(carbonyl) and these lead to the formation of linear supramolecular chains along the c axis; weak benzene-C—H⋯O(epoxide) and methine-C—H⋯O(methoxy) interactions connect these into a three-dimensional architecture. The analysis of the Hirshfeld surface confirms the presence of C—H⋯O interactions in the crystal, but also the dominance of H⋯H dispersion contacts.
TL;DR: The structure of title co-crystal consists of a 2-3,5,6-tetrakis(pyridin-2-yl)pyrazine coformer and hydrogen peroxide solvent molecules in a ratio of 1:4.75.
Abstract: The structure of the title co-crystal, C24H16N6·4.75H2O2, consists of a 2,3,5,6-tetrakis(pyridin-2-yl)pyrazine coformer and hydrogen peroxide solvent molecules in an overall ratio of 1:4.75. Three of the six H2O2 molecules modelled in the structure were found to be cross-orientationally disordered over two positions with occupancy ratios 0.846 (9):0.154 (9), 0.75 (2):0.25 (2), and 0.891 (9):0.109 (9). In the crystal, all of the peroxide molecules are linked into hydrogen-bonded chains that propagate parallel to the a axis. These chains are further linked by O—H⋯N hydrogen bonds to the pyridine groups of the main molecule.
TL;DR: The title compound was obtained from the condensation reaction of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2,4-dinitrophenylhydrazine.
Abstract: The essential part (including all the non-hydrogen atoms except two methyl carbons) of the molecule of the title compound, C21H26N4O5, lies on a mirror plane, which bisects the t-butyl groups. The conformation of the C=N bond of this Schiff base compound is E, and there is an intramolecular N—H⋯O hydrogen bond present, forming an S(6) ring motif. In the crystal, molecules are linked via O—H⋯O hydrogen bonds, forming zigzag chains propagating along the a-axis direction. There are no other significant intermolecular contacts present.
TL;DR: The molecular and crystal structures of two N-(furylmethyl)propan-2-aminium salts – the products of interaction between maleic acid and N-R-furfurylamines – were studied by X-ray diffraction and correlated with their lack of reactivity in [4 + 2] cycloaddition reactions.
Abstract: The title molecular salts, C15H20NO+·C4H3O4−, (I), and C9H15INO+·C4H3O4−, (II), have very similar molecular geometries for both cation and anion. The anions of both (I) and (II) are practically planar (r.m.s. deviations = 0.062 and 0.072 A, respectively) and adopt a rare symmetrical geometry with the hydroxy H atom approximately equidistant from the two O atoms. In their crystals, the cations and anions in both (I) and (II) form tight ionic pairs via strong N—H⋯O hydrogen bonds, with a roughly perpendicular disposition of the anion to the furan ring of the cation. This ion-pair conformation appears to correlate with the lack of reactivity of these salts in [4 + 2] cycloaddition reactions. In the extended structures of (I) and (II), the ion pairs form hydrogen-bonded chains propagating along [010] and [001], respectively, via N—H⋯O hydrogen bonds.
TL;DR: The crystal structure of dicesium hydrogen citrate has been solved using laboratory X-ray single-crystal diffraction data, refined using laboratory powder data, and optimized using density functional techniques.
Abstract: The crystal structure of dicesium hydrogen citrate, 2Cs+·C6H6O72−, has been solved using laboratory X-ray single-crystal diffraction data, refined using laboratory powder X-ray data, and optimized using density functional techniques. The Cs+ cation is nine-coordinate, with a bond-valence sum of 0.92 valence units. The CsO9 coordination polyhedra share edges and corners to form a three-dimensional framework. The citrate anion is located on a mirror plane. Its central hydroxy/carboxylate O—H⋯O hydrogen bond is short, and (unusually) intermolecular. The centrosymmetric end-end carboxylate hydrogen bond is exceptionally short (O⋯O = 2.416 A) and strong. These hydrogen bonds contribute 16.5 and 21.7 kcal mol−1, respectively, to the crystal energy. The hydrophobic methylene groups occupy pockets in the framework.
TL;DR: In (CH3)2Sn[S2CN(CH2CH2)2O]2, a skew-trapezoidal bipyramidal coordination geometry based on a C2S4 donor set is found and secondary Sn⋯S interactions lead to centrosymmetric dimeric aggregates in the crystal.
Abstract: The title compound, [Sn(CH3)2(C5H8NOS2)2], has the SnIV atom bound by two methyl groups which lie over the weaker Sn—S bonds formed by two asymmetrically chelating dithiocarbamate ligands so that the coordination geometry is skew-trapezoidal bipyramidal. The most prominent feature of the molecular packing are secondary Sn⋯S interactions [Sn⋯S = 3.5654 (7) A] that lead to centrosymmetric dimers. These are connected into a three-dimensional architecture via methylene-C—H⋯S and methyl-C—H⋯O(morpholino) interactions. The Sn⋯S interactions are clearly evident in the Hirshfeld surface analysis of the title compound along with a number of other intermolecular contacts.
TL;DR: The crystal structure and packing of the energetic compound 3,3′-bis-isoxazole-5,5′- bis-methylene dinitrate is reported and its experimental and calculated density are reported.
Abstract: The molecular structure of the title energetic compound, C8H6N4O8, is composed of two planar isoxazole rings and two near planar alkyl-nitrate groups (r.m.s deviation = 0.006 A). In the crystal, the molecule sits on an inversion center, thus Z′ = 0.5. The dihedral angle between the isoxazole ring and the nitrate group is 69.58 (8)°. van der Waals contacts dominate the intermolecular interactions. Inversion-related rings are in close slip-stacked proximity, with an interplanar separation of 3.101 (3) A [centroid–centroid distance = 3.701 (3) A]. The measured and calculated densities are in good agreement (1.585 versus 1.610 Mg m−3).