Redetermination of 4-nitro-stilbene.
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ABSTRACT:
SUBMITTER: Moreno-Fuquen R
PROVIDER: S-EPMC2960097 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The crystal structure of the title compound, C(7)H(5)NO(4), was first reported by Kurahashi, Fukuyo & Shimada [(1967). Bull. Chem. Soc. Jpn, 40, 1296]. It has been re-examined, improving the precision of the derived geometric parameters. The asymmetric unit comprises a non-planar independent mol-ecule, as the nitro and the carb-oxy substituents force each other to be twisted away from the plane of the aromatic ring by 54.9 (2) and 24.0 (2)°, respectively. The mol-ecules form a conventional dimeric unit via centrosymmetric inter-molecular hydrogen bonds.
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Project description:An improved crystal structure of the title compound, C6H6N2O3, is reported. The structure, previously solved [Li et al. (1987 ▶). Jiegou Huaxue (Chin. J. Struct. Chem.), 6, 20-24] in the ortho-rhom-bic space group Pca21 and refined to R = 0.067, has been solved in the ortho-rhom-bic space group Pbcm with data of enhanced quality, giving an improved structure (R = 0.0485). The mol-ecule adopts a planar conformation with all atoms lying on a mirror plane. The crystal structure is composed of mol-ecular sheets extending parallel to the ab plane and connected via C-H⋯O contacts involving ring H atoms and O atoms of the N-oxide and nitro groups, while van der Waals forces consolidate the stacking of the layers.
| S-EPMC3998602 | biostudies-literature
Project description:The title compound, C(18)H(21)N(3)O(3), is a potential bidentate Schiff base ligand. The whole mol-ecule is disordered with a refined site-occupancy ratio of 0.567?(4):0.433?(4) and not just one ethyl group as reported previously [Sarojini et al. (2007 ?). Acta Cryst. E63, o4782-o4782]. Using the whole mol-ecule disorder, R values are much smaller than those published. An intra-molecular O-H?N hydrogen bond generates a six-membered ring, producing an S(6) ring motif. The dihedral angle between the mean plane of the two benzene rings (major component) is 9.0?(5)°. The crystal structure shows short C?C [3.189?(15)-3.298?(12)?Å] and C?O [2.983?(5)-3.149?(13)?Å] contacts. Inter-molecular C-H?O inter-actions link neighbouring mol-ecules into dimers with R(2) (2)(18) motifs. In the crystal structure, these dimers are linked together by inter-molecular C-H?O inter-actions into one-dimensional extended chains along the b axis. The crystal structure is further stabilized by inter-molecular ?-? stacking inter-actions [centroid-centroid distances = 3.458?(8)-3.691?(6)?Å].
| S-EPMC2968344 | biostudies-literature
Project description:The structural investigation of synthesized compounds can be carried out by various spectroscopic techniques. It is an important prospect in order to elucidate the structure of the desired products before being further utilized. The preparation of new p-nitro stilbene Schiff base derivatives as an electrochemical DNA potential spacer was synthesized using (E)-4-(4-nitrostyryl)aniline from Heck reaction with aldehydes in ethanolic solution. The data presented here in this article contains FTIR, UV-Vis and 1H and 13C NMR of (E)-4-(4-nitrostyryl)aniline and nitrostyryl aniline derivatives.
| S-EPMC7184124 | biostudies-literature
Project description:The CCD-data based redetermination of the crystal structure of the title compound, magnesium chromate(VI) penta-hydrate, confirms in principle the previous study based on precession film data [Bertrand et al. (1971 ?). C. R. Hebd. Seances Acad. Sci. Serie C, 272, 530-533.], but with all atoms refined with anisotropic displacement parameters and with all H atoms localized. This allowed an unambiguous assignment of the hydrogen-bonding pattern. MgCrO4·5H2O adopts the MgSO4·5H2O structure type. It contains two Mg(2+) sites on special positions with site symmetry -1, one tetra-hedral CrO4 group and five water mol-ecules. Four of them coordinate to the Mg(2+) cation, and one is an uncoordinating lattice water mol-ecule. The octa-hedral environment of the Mg(2+) cation is completed by two axial O atoms of CrO4 tetra-hedra. This arrangement leads to the formation of chains parallel to [011]. Adjacent chains are linked through O-H?O hydrogen bonds (one of them bifurcated), involving both the coordi-nating and lattice water mol-ecules, into a three-dimensional network.
| S-EPMC3793667 | biostudies-literature
Project description:The structure of the title compound {systematic name: 4-[4-(4-chloro-phen-yl)-4-hy-droxy-piperidin-1-yl]-N,N-dimethyl-2,2-di-phenyl-butanamide monohydrate}, C(29)H(33)ClN(2)O(2)·H(2)O, has been redetermined at 170?(2)?K. The redetermination is of significantly higher precision than the previous structure determination at room temperature and includes the H-atom coordinates that were not included in the previous report [Germain et al. (1977 ?). Acta Cryst. B33, 942-944]. It consists of a piperidin-1-yl ring in a distorted chair conformation, with the N,N-dimethyl-?,?-diphenyl-butyramide and the 4-chloro-phenyl and hy-droxy groups bonded in para positions and an external water mol-ecule within the asymmetric unit. The dihedral angles between the mean plane of the piperidine ring and the 4-chloro-phenyl and two benzene rings are 83.4?(5), 76.4?(2) and 85.9?(2)°, respectively. The two benzene rings are inclined to one another by 50.8?(6)°. In the crystal, mol-ecules are linked by O-H?O and O-H?N hydrogen bonds and weak C-H?O intermolecular interactions, forming an infinite two-dimensional network along [110].
| S-EPMC3275278 | biostudies-literature
Project description:Single crystals of europium(III) scandate(III), with ideal formula EuScO(3), were grown from the melt using the micro-pulling-down method. The title compound crystallizes in an ortho-rhom-bic distorted perovskite-type structure, where Eu occupies the eightfold coordinated A sites (site symmetry m) and Sc resides on the centres of corner-sharing [ScO(6)] octa-hedra (B sites with site symmetry ). The structure of EuScO(3) has been reported previously based on powder diffraction data [Liferovich & Mitchell (2004). J. Solid State Chem.177, 2188-2197]. The results of the current redetermination based on single-crystal diffraction data shows an improvement in the precision of the structral and geometric parameters and reveals a defect-type structure. Site-occupancy refinements indicate an Eu deficiency on the A site coupled with O defects on one of the two O-atom positions. The crystallochemical formula of the investigated sample may thus be written as (A)(?(0.032)Eu(0.968))(B)ScO(2.952).
| S-EPMC2968298 | biostudies-literature
Project description:Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.
| S-EPMC3052054 | biostudies-literature
Project description:The structure of the title compound, C(7)H(9)NO(2)S, was previously determined from powder diffraction data [Tremayne, Seaton & Glidewell (2002). Acta Cryst. B58, 823-834]. It has now been refined to a significantly higher precision. The amino N-atom is bent with a C-C-S-N torsion angle of -65.8?(2)deg;. In the crystal, mol-ecules are packed into a three-dimensional framework/supramolecular structure through hydrogen bonds between the two H atoms of the sulfonamide group and sulfonyl O atoms of neighbouring mol-ecules.
| S-EPMC2970068 | biostudies-literature
Project description:In contrast to the previous structure determinations of the title structure, (NH(4))(2)[MoS(4)], the present determination at 173?K localized the positions of the H atoms. The title structure belongs to the ?-K(2)SO(4) family and all the ions are located on crystallographic mirror planes. The ions are held together by N-H?S hydrogen bonds (some of which are bifurcated), forming a three-dimensional network. One of the N atoms has nine contacts to the S atoms shorter than 4?Å, and the other has ten.
| S-EPMC2979694 | biostudies-literature