共查询到20条相似文献,搜索用时 31 毫秒
1.
G. Chevrier J. M. Kiat J. A. Güida A. Navaza 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(3):i27-i29
The crystal of barium pentacyanonitrosylferrate trihydrate {barium nitroprusside trihydrate, Ba[Fe(CN)5(NO)]·3H2O} has been studied by neutron diffraction at 20 K. The study was performed to characterize the structural phase generated by the phase transition undergone by the crystals at 80 K, at which temperature the unit‐cell volume doubles. This crystal phase still exists at 20 K. The crystal structure, in space group P1, is completely ordered. The positional changes of the water molecules in the present structure with respect to those of the compound at 105 K are presented. 相似文献
2.
Anwar Usman Suchada Chantrapromma Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m45-m47
The title compound, bis(2,4‐dinitrophenolato‐κ2O,O′)(1,4,7,10,13,16‐hexaoxadecane‐κ6O)barium(II), [Ba(C6H3N2O5)2(C12H24O6)], is a 1:1 complex of barium(II)–2,4‐dinitrophenolate and 1,4,7,10,13,16‐hexaoxacyclooctadecane (18‐crown‐6). Its structure is located on a crystallographic inversion centre. The temperature dependence of the crystal structure has been studied. The monoclinic β angle of the P21/n space group increases with increasing temperature. The packing structure of the complex is stabilized by intermolecular C—H?O interactions. 相似文献
3.
Martin Nieger Wilm‐Christian Haase Karl Heinz Dtz 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):e174-e175
The synthesis and crystal structure of pentacarbonyl(pyrrolidin‐2‐ylidene)chromium(0), [Cr(C4H7N)(CO)5], is reported. The compound shows strong interaction between the lone pair at nitrogen and the carbene C atom, and weak intermolecular hydrogen bonds. 相似文献
4.
Vladimir V. Chernyshev Victor A. Tafeenko Svetlana Yu. Ryabova Eduard J. Sonneveld Hendrik Schenk 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):982-984
The evidence for thermal isomerization of the title compound, C24H15N5O2, into 2‐[(4‐nitrophenyl)phenylamino]‐5H‐pyrido[3,2‐b]indole‐3‐carbonitrile has been obtained as a consequence of crystal structure determinations from laboratory powder data. 相似文献
5.
Paul E. Kruger Philip R. Mackie Mark Nieuwenhuyzen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):e532-e532
The title compound, C6HCl3N2O4, is an intermediate in the synthesis of 1,3,5‐trichloro‐2,4,6‐trinitrobenzene. The crystal structure at 153 K shows no major deviations from the previously reported structure at 295 K other than the expected contraction of the a and c axes and, correspondingly, the β angle. 相似文献
6.
Ronald D. Clark Angela Romero Oleg Ya. Borbulevych Mikhail Yu. Antipin Vladimir N. Nesterov Tatiana V. Timofeeva 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):336-338
The structures of the potential non‐linear optical (NLO) materials N‐[2‐(isopropylamino)‐5‐nitrophenyl]acetamide, (I) C11H15N3O3, and N‐[2‐(butylamino)‐5‐nitrophenyl]acetamide, (II) C12H17N3O3, have been investigated by X‐ray analysis. To compare them with the structure of N‐[2‐(dimethylamino)‐5‐nitrophenyl]acetamide, (III) C10H13N3O3, a known NLO compound, we had to redetermine the structure of (III), since it was described only briefly in the literature. There are two molecules in the asymmetric unit of compound (I), which have different orientations of the substituents with respect to the benzene ring. The packing of molecules in (II) and (III) contains stacks but both (I) and (II) crystallize in a centrosymmetric space group, which renders them inappropriate for NLO applications. 相似文献
7.
Marco Crisma Claudio Toniolo 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(4):o215-o217
The preparation, characterization, and molecular and crystal structures of the title compound [IUPAC name: 2‐nitrophenyl 2‐methyl‐2‐(para‐toluenesulfonylamino)propanoate], C17H18N2O6S, are reported. The phenyl group is almost perpendicular to the plane of the adjacent ester moiety. One O atom of the nitro group is wedged between the two ester O atoms. The implications of this peculiar conformation for the chemistry of ortho‐nitrophenyl esters in peptide synthesis are discussed. 相似文献
8.
Karl Hensen Alexander Lemke Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e565-e566
The reaction of 2‐methylpyridine with TiBr4 affords tetrabromo(2‐methylpyridine‐N)titanate(IV), C6H7Br4NTi. The environment around the Ti atom can be described as a slightly distorted trigonal bipyramid, with the nitrogen base occupying an equatorial position. The crystal structure of the title compound is isomorphous with tetrachloro(2‐methylpyridine‐N)titanate(IV). 相似文献
9.
L. Vijayalakshmi V. Parthasarathi P. Manishanker 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):e403-e404
The crystal structure of the title compound, C13H10ClNO, confirms that it exists as a nitrone. The geometry about C=N is Z. The relevant torsion angles indicate trans and cis conformations around the nitrone bond. 相似文献
10.
Lamine Hamdellou Olivier Hernandez Jean Meinnel 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):o557-o560
The structures of 4‐dimethylamino‐β‐nitrostyrene (DANS), C10H12N2O2, and 4‐dimethylamino‐β‐ethyl‐β‐nitrostyrene (DAENS), C12H16N2O2, have been solved at T = 100 K. The structure solution for DANS was complicated by the presence of a static disorder, characterized by a misorientation of 17% of the molecules. The molecule of DANS is almost planar, indicating significant conjugation, with a push–pull effect through the styrene skeleton extending up to the terminal substituents and enhancing the dipole moment. As a consequence of this conjugation, the hexagonal ring displays a quinoidal character; the lengths of the C—N [1.3595 (15) Å] and C—C [1.448 (2) Å] bonds adjacent to the benzene ring are shorter than single bonds. The molecules are stacked in dimers with antiparallel dipoles. In contrast, the molecule of DAENS is not planar. The ethyl substituent pushes the nitropropene group out of the benzene plane, with a torsion angle of −21.9 (3). Nevertheless, the molecule remains conjugated, with a shortening of the same bonds as in DANS. 相似文献
11.
Shang Shan Duan‐Jun Xu Chen‐Hsiung Hung Jing‐Yun Wu Michael Y. Chiang 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o135-o136
Crystals of the title compound, C13H10N4O4, were obtained from a condensation reaction of benzaldehyde and 2,4‐dinitrophenylhydrazine. The molecule assumes an approximately planar E configuration. Within the dinitrophenyl moiety, the average distance for the aromatic C—C bonds close to the imino group [1.417 (3) Å] is appreciably longer than the average distance for the other aromatic C—C bonds in the same phenyl ring [1.373 (3) Å]. This increased distance may be a result of the overlap of the non‐bonding orbital of the imino N atom with the π orbitals of the arene. It is likely that π–π stacking exists in the crystal structure. 相似文献
12.
Xinjiang Huang Genevieve H. Kuhn Vladimir N. Nesterov Boris B. Averkiev Benjamin Penn Mikhail Yu. Antipin Tatiana V. Timofeeva 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o624-o628
Syntheses and X‐ray structural investigations have been carried out for (E)‐(4‐hydroxyphenyl)(4‐nitrophenyl)diazene, C12H9N3O3, (Ia), (E)‐(4‐methoxyphenyl)(4‐nitrophenyl)diazene, C13H11N3O3, (IIIa), and (E)‐[4‐(6‐bromohexyloxy)phenyl](4‐cyanophenyl)diazene, C19H20BrN3O, (IIIc). In all of these compounds, the molecules are almost planar and the azobenzene core has a trans geometry. Compound (Ia) contains four and compound (IIIc) contains two independent molecules in the asymmetric unit, both in space group P (No. 2). In compound (Ia), the independent molecules are almost identical, whereas in crystal (IIIc), the two independent molecules differ significantly due to different conformations of the alkyl tails. In the crystals of (Ia) and (IIIa), the molecules are arranged in almost planar sheets. In the crystal of (IIIc), the molecules are packed with a marked separation of the azobenzene cores and alkyl tails, which is common for the solid crystalline precursors of mesogens. 相似文献
13.
Miao Du Zhi‐Liang Shang Qiang Xu Ruo‐Hua Zhang Xue‐Bing Leng Xian‐He Bu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):769-770
The crystal structure of the title compound, [CoCl‐(C16H26N6)]ClO4, consists of discrete [CoCl(C16H26N6)]+ cations and perchlorate anions. The five‐coordinate CoII atom has four nitrogen donors from the new mesocyclic ligand 1,5‐bis(1‐methyl‐1H‐imidazol‐2‐ylmethyl)‐1,5‐diazacyclooctane [Co—N 2.046 (3)–2.214 (4) Å], and a chloride anion at the apical site [Co—Cl 2.3184 (13) Å]. The coordination geometry of the complex is essentially square pyramidal. The mesocyclic ligand takes a boat–chair configuration and the two imidazole pendants are not coplanar. The dihedral angle between the two imidazole planes is 15.97°. An H atom from the 1,5‐diazacyclooctane group effectively blocks the axial coordination site opposite the Cl ligand. 相似文献
14.
Xiao‐Ming Ren Yan Xu Chuan‐Jiang Hu Qing‐Jin Meng Chang‐Sheng Lu Hua‐Ting Wang 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1499-1500
The maleonitrile moiety of the title compound, (2Z)‐2,3‐bis[(4‐nitrobenzyl)sulfanyl]but‐2‐enedinitrile, C18H12N4O4S2, is almost planar. The two benzene rings are nearly parallel to each other and perpendicular to the maleonitrile plane. Intermolecular S?S and π–π interactions are observed in the crystal structure. 相似文献
15.
Sergei D. Kirik Alexander I. Blokhin Ruslan F. Mulagaleev 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):m445-m447
The water‐insoluble title compound, octakis(μ‐acetato‐κ2O:O)octakis(μ‐nitroso‐κ2N:O)octapalladium(II), [Pd8(CH3COO)8(NO)8], was precipitated as a yellow powder from a solution of palladium nitrate in nitric acid by adding acetic acid. Ab initio crystal structure determination was carried out using X‐ray powder diffraction techniques. Patterson and Fourier syntheses were used for atom locations, and the Rietveld technique was used for the final structure refinement. The crystal structure is of a molecular type. The skeleton of the [Pd8(CH3COO)8(NO)8] molecule is constructed as a tetragonal prism with Pd atoms at the vertices. The eight NO− groups are in bridging positions along the horizontal edges of the prism. The N and O atoms of each nitroso group coordinate two different Pd atoms. The vertical edges present Pd⋯Pd contacts with a short distance of 2.865 (1) Å. These Pd atoms are bridged by a pair of acetate groups in a cis orientation with respect to each other. The complex has crystallographically imposed 4/m symmetry; all C atoms of the acetate groups are on mirror planes. The unique Pd atom lies in a general position and has square‐planar coordination, consisting of three O and one N atom. 相似文献
16.
De‐Chun Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o351-o352
In the title compound, N‐(2‐methoxyphenyl)‐4‐nitrobenzylideneamine, C14H12N2O3, the two phenyl rings make a dihedral angle of 48.0 (2)° and the nitro group is at an angle of 6.5 (1)° with respect to its attached phenyl ring. In the crystal structure, molecules are related as centrosymmetric pairs through π–π interactions and are further connected through strong C—H?O hydrogen bonds [C?O 3.4259 (17) Å and C—H?O 167°], forming molecular stacks along [100]. These stacks associate further through longer C—H?O interactions, forming two‐dimensional networks. In the c direction, there are only weak van der Waals interactions. The relationship between the molecular planarity and its centrosymmetry is also briefly described. 相似文献
17.
Anwar Usman Suchada Chantrapromma Hoong-Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(12):1443-1446
The title compound, 3,5,7-triaza-1-azoniatricyclo[3.3.1.13,7]decane 2,4-dinitrophenolate monohydrate, C6H13N4+·C6H3N2O5−·H2O, the 1:1 hydrate adduct of hexamethylenetetramine (HMT) and 2,4-dinitrophenol, undergoes a temperature phase transition. In the room-temperature phase, the adduct crystallizes in the monoclinic P21/m space group, whereas in the low-temperature phase, the adduct crystallizes in the triclinic P space group. This phase transition is reversible, with the transition temperature at 273 K, and the phase transition is governed by hydrogen bonds and weak interactions. In both these temperature-dependent polymorphs, the crystal structure is alternately layered with sheets of hexamethylenetetramine and sheets of dinitrophenol stacked along the c axis. The hexamethylenetetramine and dinitrophenol moieties are linked by intermolecular hydrogen bonds. The water molecule in the adduct plays an important role, forming O—H⋯O hydrogen bonds which, together with C—H⋯O hydrogen bonds, bridge the adducts into molecular ribbons. Extra hydrogen bonds and weak interactions exist for the low-temperature polymorph and these interconnect the molecular ribbons into a three-dimensional packing structure. Also in these two temperature-dependent polymorphs, dinitrophenol acts as a hydrogen-bond acceptor and HMT acts as a hydrogen-bond donor. 相似文献
18.
Arthur J. Schultz Brian N. Figgis Alexandre N. Sobolev 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1289-1291
The crystal structure of Na2Fe(CN)5(NO)·2D2O, disodium pentacyanonitrosylferrate(III) bis(dideuterium oxide), has been determined by X‐ray diffraction at 11 and 293 K, and by neutron diffraction at 15 K. The accurate and extensive data sets lead to more precise determinations than are available from earlier work. The agreement in atomic positional and displacement parameters between the determinations at low temperature is very good. 相似文献
19.
Laura Andrau Jonathan White 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):o60-o61
The crystal structure of N‐methyl‐4‐piperidyl 2,4‐dinitrobenzoate, C13H15N3O6, (I), at 130 (2) K reveals that, in the solid state, the molecule exists in the equatorial conformation, (Ieq). Thus, the through‐bond interaction present in the axial conformation, (Iax), is not strong enough to overcome the syn–diaxial interactions between the axial methyl substituent and the axial H atoms on the two piperidyl ring C atoms either side of the ester‐linked ring C atom. The carboxylate group in (I) is orthogonal to the aromatic ring, in contrast with other 2,4‐dinitrobenzoates, which are coplanar. The piperidyl–ester C—O bond distance is 1.467 (3) Å, which is actually shorter than other equatorial cyclohexyl–ester C—O distances. This shorter piperidyl–ester C—O bond distance is due to the reduced electron demand of the orthogonal ester group. 相似文献
20.
David Drouard Sandrine Py Marie‐Thrse Averbuch Christian Philouze Yannick Valle 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1079-1080
The preparation and crystal structure of the title compound, C20H25NO2, are described. The N atom substituent of the nitrone function adopts a conformation which minimizes the 1,3‐allylic strain. 相似文献