共查询到20条相似文献,搜索用时 15 毫秒
1.
Michael I. Bruce Nicholas J. Head Brian W. Skelton Allan H. White 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):o60-o61
The principal determinants of packing in crystals of the title compound, C12H10O2, which has crystallographically imposed inversion symmetry, are interactions between the alkyne H atoms and the methoxy O atoms [H⋯O = 2.39 (1) Å]. 相似文献
2.
Russell G. Baughman Kenneth L. Martin Rajendra K. Singh James O. Stoffer 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o103-o106
In 2,4‐dihydroxybenzaldehyde 2,4‐dinitrophenylhydrazone N,N‐dimethylformamide solvate {or 4‐[(2,4‐dinitrophenyl)hydrazonomethyl]benzene‐1,3‐diol N,N‐dimethylformamide solvate}, C13H10N4O6·C3H7NO, (X), 2,4‐dihydroxyacetophenone 2,4‐dinitrophenylhydrazone N,N‐dimethylformamide solvate (or 4‐{1‐[(2,4‐dinitrophenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐dimethylformamide solvate), C14H12N4O6·C3H7NO, (XI), and 2,4‐dihydroxybenzophenone 2,4‐dinitrophenylhydrazone N,N‐dimethylacetamide solvate (or 4‐{[(2,4‐dinitrophenyl)hydrazono]phenylmethyl}benzene‐1,3‐diol N,N‐dimethylacetamide solvate), C19H14N4O6·C4H9NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent molecule. 相似文献
3.
Gregori A. Caignan Elizabeth M. Holt 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):934-935
The title compound, C21H27NO6, has been crystallized from ethanol containing nitrobenzene and shows the phenyl ring, B, in an ap conformation. This structure may be compared with that of the molecule crystallized from ethanol alone, in which the B ring is seen in an sp conformation. The isolation of this rotamer has implications for the understanding of the docking of calcium beta‐blocking dihydropyridine molecules with their receptor site. 相似文献
4.
David J. Wiedenfeld Vladimir N. Nesterov Mark A. Minton Crystal L. Montoya 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):o536-o538
The title compounds, 1‐chloro‐3,6‐dimethoxy‐2,5‐dimethylbenzene, (IIIa), and 1‐chloro‐3,6‐dimethoxy‐2,4‐dimethylbenzene, (IIIb), both C10H13ClO2, were obtained from 2,5‐ and 2,6‐dimethyl‐1,4‐benzoquinone, respectively, and are intermediates in the synthesis of ammonium quinone derivatives. The isomers have different substituents around the methoxy groups and crystallize in different space groups. In both molecules, the methoxy groups each have different orientations with respect to the benzene ring. In both cases, one methoxy group lies in the plane of the ring and can participate in conjugation with the aromatic system, while the second is almost perpendicular to the plane of the aromatic ring. The C—O—C bond angles around these substituents are also different: 117.5 (4) and 118.2 (3)° in (IIIa) and (IIIb), respectively, when the methoxy groups lie in the plane of the ring, and 114.7 (3) and 113.6 (3)° in (IIIa) and (IIIb), respectively, when they are out of the plane of the ring. 相似文献
5.
Hiroyuki Hosomi Shigeru Ohba Yoshikatsu Ito 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):e149-e150
In the three title crystal structures 4‐(dimethylamino)pyridinium 2,4‐dinitrobenzoate, (I), 4‐(dimethylamino)pyridinium 3,4‐dinitrobenzoate, (II), and 4‐(dimethylamino)pyridinium 3,5‐dinitrobenzoate, (III), all C7H11N2+·C7H3N2O6?, the ions are connected by an N—H?O hydrogen bond. Dihedral angles between the pyridine and phenyl rings are 69.9 (1), 26.7 (1) and 56.2 (1)° in (I), (II) and (III), respectively. Donor–acceptor π–π stacking is observed in (II) and (III), but not in (I). 相似文献
6.
Guo‐Wu Rao Wei‐Xiao Hu 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(5):o281-o282
The title compound, C22H24N4O4, was prepared from propyl chloroformate and 3,6‐diphenyl‐1,2‐dihydro‐s‐tetrazine. This reaction yields the title compound rather than dipropyl 3,6‐diphenyl‐1,4‐dihydro‐s‐tetrazine‐1,4‐dicarboxylate. The 2,3‐diazabutadiene group in the central six‐membered ring is not planar; the C=N double‐bond length is 1.285 (2) Å, and the average N—N single‐bond length is 1.401 (3) Å, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie 0.3268 (17) Å from the plane of the ring. The molecule has twofold crystallographic symmetry. 相似文献
7.
Satomi Niwayama Elizabeth M. Holt 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):e300-e301
The title compound, C12H16O6, prepared by a standard synthetic method, was determined by single‐crystal X‐ray crystallography to exist with a cyclopropane ring fused to a cyclopentene ring. Comparison of the unit‐cell dimensions and space group of this material with those of a crystal of the same material prepared using a route involving pig liver esterase hydrolysis shows them to be identical. 相似文献
8.
F. Betül Kaynak Süheyla
zbey Turan
ztürk Erdal Erta 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):926-928
In the title compound, C17H10S5, the dithiine ring adopts a boat conformation while the dithiole ring has an envelope conformation. The phenyl groups are planar and make dihedral angles of 40.7 (2) and 59.8 (2)° with the best plane of the thiine ring. The shortest intermolecular S?S contact is 3.305 (2) Å. 相似文献
9.
Manuela Ramos Silva Ana Matos Beja Jose Antonio Paixo Abilio J. F. N. Sobral Lucia M. L. Cabral A. M. d'A. Rocha Gonsalves 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):o562-o563
Molecules of the title 2,5‐dioxopiperazinedione derivative, C8H10N2O6, occupy centres of symmetry in the crystal structure. The six‐membered ring has an almost planar conformation, with the substituent on nitrogen nearly perpendicular to the ring. The ideal geometry of the isolated molecule, as determined by ab initio HF–LCAO quantum‐mechanical calculations, is slightly more puckered than that observed in the solid state. In the crystal structure, a strong hydrogen bond joins neighbouring molecules, thus forming a network of rectangular (30) rings. 相似文献
10.
Simon J. Coles Christopher W. Hall Michael B. Hursthouse 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):o29-o31
The two title calix[4]arene compounds, C34H32O8, (I), and C36H36O8·CH3Cl, (II), respectively, which differ only in the size of the alkyl function on the pendant ester group, are compared. Compound (I) forms a novel supramolecular array, whilst (II) fails to do so due to accommodating a chloroform guest molecule in the lower‐rim cavity. 相似文献
11.
Anthony Linden Fatemeh Ghorbani‐Salman Pour Roland A. Breitenmoser Heinz Heimgartner 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):634-637
The morpholine ring of the title dione, C13H15NO3, shows a boat conformation that is distorted towards a twist‐boat, with the boat ends being the two Csp3 atoms of the ring. The benzyl substituent is in the favoured `exo' position. In the monothione derivative, (±)‐6‐benzyl‐3,3‐dimethyl‐5‐thioxomorpholin‐2‐one, C13H15NO2S, this ring has a much flatter conformation that is midway between a boat and an envelope, with the dimethyl end being almost planar. The orientation of the benzyl group is `endo'. The dithione derivative, (±)‐6‐benzyl‐3,3‐dimethylmorpholine‐2,5‐dithione, C13H15NOS2, has two symmetry‐independent molecules, which show different puckering of the morpholine ring. One molecule has a flattened envelope conformation distorted towards a screw‐boat, while the conformation in the other molecule is similar to that in the monothione derivative. Intermolecular hydrogen bonds link the molecules in the three compounds, respectively, into centrosymmetric dimers, infinite chains, and dimers made up of one of each of the symmetry‐independent molecules. 相似文献
12.
Suchada Chantrapromma Hoong‐Kun Fun Ibrahim Abdul Razak Nisakorn Saewon Chatchanok Karalai Kan Chantrapromma 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e598-e599
In the title compound, C19H20O8, the benzene rings are nearly perpendicular to each other [dihedral angle 80.2 (2)°]. The carboxy group is twisted out while both the methoxy and acetyl groups are almost coplanar with their attached benzene rings. The hydroxy group is involved in an intramolecular O—H?O hydrogen bond with the acetyl O atom and the compound is connected through an intermolecular O—H?O contact to form a dimer. The crystal structure is stabilized by intermolecular O—H?O hydrogen bonds. 相似文献
13.
J.‐C. Wallet Elies Molins Carlos Miravitlles 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):e414-e414
Crystals of a second triclinic modification of the title compound, 2‐(2,6‐dimethoxyphenyl)‐4H‐1‐benzopyran‐4‐one, C17H14O4, were grown from a hot cyclohexane solution. In the molecule, the O—C—C—C torsion angle at the junction between the benzopyran and phenyl rings is 67.6 (3)°. 相似文献
14.
Ramis Rao Subramanian Shanmuga S. Anandan Kuan Hiang Kwek Kum Sang Low S. Shanmuga Sundara Raj Hoong‐Kun Fun Ibrahim Abdul Razak John V. Hanna Seik Weng Ng 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):e292-e294
The monoclinic cell of dicyclohexylammonium 2,4‐dichlorophenoxyacetate contains four C12H24N+·C5H8Cl2O3? ion pairs. The ammonium N atom is hydrogen bonded to the oxygen ends of two carboxyl groups to form a 12‐membered O—C—O?HNH?O—C—O?HNH ring. In (2,4‐dichlorophenoxylacetato)bis(triphenylphosphine)silver(I), [Ag(C8H5Cl2O3)(C18H15P)2], the carboxyl CO2 unit chelates to the Ag atom in an anisobidentate manner [Ag—O = 2.436 (2) and 2.517 (2) Å]; the Ag atom shows distorted tetrahedral geometry. 相似文献
15.
Christophe M. L. Vande Velde Herman J. Geise Frank Blockhuys 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o21-o24
In the title compound, C30H34O8, molecular symmetry is coincident with crystallographic inversion symmetry. A three‐dimensional network is generated containing both C—H·π and C—H·n(O) interactions. A comparison of the geometry of this molecule and the structure of a number of 2,4,6‐trimethoxy‐substituted analogues is provided. 相似文献
16.
John Reglinski Michelle K. Taylor Alan R. Kennedy 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(3):o169-o172
We have isolated and crystallographically characterized the three homologous compounds N,N′‐bis(2‐methoxybenzylidene)ethane‐1,2‐diamine (MeSalen), C18H20N2O2, N,N′‐bis(2‐methoxybenzylidene)propane‐1,3‐diamine (MeSalpr), C19H22N2O2, and N,N′‐bis(2‐methoxybenzylidene)butane‐1,4‐diamine (MeSalbu), C20H24N2O2. In contrast with MeSalpr, the molecules of MeSalen and MeSalbu, which have an even number of methylene units, have crystallographic symmetry. Comparing these methoxy‐substituted species with their hydroxy equivalents shows that the aryl rings rotate upon removal of the O—H⋯N hydrogen bonds. The packing of MeSalen and MeSalpr is controlled by C—H⋯π interactions, whereas that of MeSalbu has only van der Waals contacts. 相似文献
17.
T. S. Basu Baul S. Dhar E. R. T. Tiekink 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1280-1281
The title compound, C14H12N2O4, shows an E conformation about the diazenyl N atoms. The crystal structure features layers of molecules with the primary connection between the layers afforded by carboxylic acid dimer motifs; no evidence for extensive π–π stacking between the layers was found. 相似文献
18.
Dimethyl 2‐{[2‐(methoxycarbonyl)‐1‐(methoxycarbonylmethyl)pyrrol‐4‐yl]methylene}propanedioate
Jan Lokaj Viktor Kettmann Viktor Milata Pavol Hodul Peter Kotta Ognyan Petrov 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):973-974
The title compound, C15H17NO8, is a pyrrole–ethene derivative with potential biological activity. Although a large part of the molecule is planar, there is no structural evidence for any conjugation push–pull effect across the ethylenic bond, which is usually observed for substituted ethylenes; π‐electron delocalization appears to be restricted to the 2‐(methoxycarbonyl)pyrrole moiety. 相似文献
19.
Tali Lavy Yana Sheynin Moshe Kapon Menahem Kaftory 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):o50-o53
The crystal structures of three 1:2 inclusion compounds that consist of host molecule 2,5‐diphenylhydroquinone (C18H14O2) and the guest molecules 2‐pyridone (C5H5NO), 1,3‐diphenyl‐2‐propen‐1‐one (chalcone, C15H12O) and 1‐(4‐methoxyphenyl)‐3‐phenyl‐2‐propen‐1‐one (4′‐methoxychalcone, C16H14O2) were determined in order to study the ability of guest molecules in inclusion compounds to undergo photoreaction. All of the crystals were found to be photoresistant. The three inclusion compounds crystallize in triclinic space group . In each case, the host/guest ratio is 1:2, with the host molecules occupying crystallographic centers of symmetry and the guest molecules occupying general positions. The guest molecules in each of the inclusion compounds are linked to the host molecules by hydrogen bonds. In the inclusion compound where the guest molecule is pyridone, the host molecule is disordered so that the hydroxy groups are distributed between two different sites, with occupancies of 0.738 (3) and 0.262 (3). The pyridone molecules form dimers via N—H⋯O hydrogen bonds. 相似文献
20.
Mario Cetina Marijana Juki Vladimir Rapi Amalija Golobi
《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):m212-m214
In the title compound, [Fe(C7H7O2)2], the cyclopentadienyl rings and the two attached methoxycarbonyl groups, in an anti arrangement, form an extended π‐conjugated system. The Fe—C distances range from 2.035 (3) to 2.061 (3) Å and the average value of the C—C bond lengths in the two cyclopentadienyl rings is 1.419 (5) Å. The rings are almost parallel to one another [1.0 (2)°] and are mutually twisted from an eclipsed conformation by only 1.8 (3)° (average value). The methoxycarbonyl groups are twisted out of the plane of the cyclopentadienyl rings by 6.5 (4) and 15.7 (4)°, respectively. The molecules are joined into dimers by intermolecular C—H⃛O hydrogen bonds that form ten‐membered rings. The same types of hydrogen bonds form eight‐membered rings and infinite chains along the b axis. 相似文献