共查询到20条相似文献,搜索用时 873 毫秒
1.
Michael Bolte Alexander Degen Stephan Rühl 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):444-445
The reaction of dimedone with 2,6‐dichlorobenzaldehyde leads to the title compound, C23H26Cl2O4. In principle, the reaction could yield eight different stereoisomers. We have found four of them in the same crystal as two enantiomeric pairs of diastereomers, which means that the asymmetric unit is built up of two different diastereomers. Two of the three chiral centres display the same configuration, while the third is different in the two molecules in the asymmetric unit. The packing of the molecules is stabilized by hydrogen bonds between the hydroxy group and the carbonyl group attached to the cyclohexene ring, forming chains in which the different diastereomers alternate. 相似文献
2.
Juliet A. Gerrard Susie J. Meade Jonathan C. Morris Peter J. Steel 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1251-1253
The orthorhombic form of 2‐hydroxycyclopent‐2‐enone, C5H6O2, consists of chains of hydrogen‐bonded molecules aligned along a twofold screw axis. The monoclinic form contains two independent molecules, which have different orientations of the hydroxyl proton, and which assemble into ribbons along a twofold screw axis. 相似文献
3.
Jia‐Xiang Yang Yu‐Peng Tian Qing‐Liang Liu Yong‐Shu Xie Hoong‐Kun Fun Suchada Chantrapromma Ibrahim Abdul Razak 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m43-m44
In the title compound, [Fe(C5H5)(C16H12N3OS)], the 8‐aminoquinoline and acylthiourea moieties are almost planar. There are two perpendicular arrangements of the molecules in the crystal with slightly different conformations. The two cyclopentadienyl rings in each molecule are parallel and eclipsed. 相似文献
4.
Anthony Linden Agnieszka Majchrzak Jovita Cavegn Grzegorz Mloston Heinz Heimgartner 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o480-o484
The four oligosulfanes, bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutan‐1‐yl)disulfane, C16H24Cl2O2S2, (III), 1,3‐bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutan‐1‐yl)trisulfane, C16H24Cl2O2S3, (V), 1,4‐bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutan‐1‐yl)tetrasulfane, C16H24Cl2O2S4, (VII), and 1,6‐bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutan‐1‐yl)hexasulfane, C16H24Cl2O2S6, (VIII), all have similar geometric parameters, with the C—C bond lengths involving the chloro‐substituted cyclobutanyl C atom being elongated to about 1.59 Å. There are two molecules in the asymmetric units of the tri‐ and tetrasulfanes, and the molecules in the latter compound have local C2 symmetry. The molecule of the hexasulfane has crystallographic C2 symmetry. Most of the cyclobutanyl rings are not perfectly planar and have slight but varying degrees of distortion towards a flattened tetrahedron. The polysulfane chain in each structure has a helical conformation, with each additional S atom in the chain adding approximately one quarter of a turn to the helix. 相似文献
5.
Ivan Leban Boenna Golankiewicz Joanna Zeidler Gerald Giester Joe Kobe 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o133-o135
In the title compound, C13H13N5O4·H2O (4,5′‐cyclowyosine·H2O), the cyclization forces a syn arrangement of the aglycon with respect to the sugar moiety. The ribofuranose part of the molecule displays a β‐d configuration with an envelope C1′‐endo pucker. The molecules are arranged in columns along the short a axis and are linked to water molecules through O—H?O and O—H?N hydrogen bonds. 相似文献
6.
Swastik Mondal Monika Mukherjee Arnab Roy Debabrata Mukherjee Madeleine Helliwell 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o474-o476
In the title compound, C13H22O3, the asymmetric unit has two independent molecules linked by a strong O—H?O hydrogen bond. The cyclohexane ring is trans fused to the cyclopentane ring bridged through an ethyl moiety. The hydroxyl groups act as donors as well as acceptors, resulting in an extensive two‐dimensional hydrogen‐bonded network in the (011) plane. Intermolecular O—H?O bonds between centrosymmetrically related molecules form a four‐membered supramolecular assembly, leading to infinite chains parallel to the [01] direction, crosslinked in the [100] direction. 相似文献
7.
Joseph P. A. Harrity Harry Adams Mark W. Davies Robert A. J. Wybrow Christopher N. Johnson 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o168-o169
A novel [3+2]‐cycloaddition reaction of alkynylboronates and nitrile oxides gave the title compound, C22H32BNO3, as a single regioisomer. The X‐ray crystal structure analysis of this compound shows two independent molecules in the asymmetric unit, each with approximately coplanar isoxazole and boronate rings. 相似文献
8.
Dmitrii S. Yufit Judith A. K. Howard Sergei I. Kozhushkov Rafael R. Kostikov Armin de Meijere 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):968-969
The central three‐membered ring in the title compound, trans‐1,1′,1′′‐cyclopropane‐1,2,3‐triyltris(cyclopropanol), C12H18O3, shows pronounced asymmetry of the bond lengths, which is induced by the different orientations of the substituents. A network of hydrogen bonds links the molecules into sheets. 相似文献
9.
S. M. Malathy Sony M. Kuppayee M. N. Ponnuswamy D. Bhasker Reddy V. Padmavathi Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o678-o680
Due to steric repulsions, the cyclohexane ring in the title compound, C23H24N2O5·H2O, shows some bond‐length abnormalities and adopts a chair conformation. The pyrimidine and cyclohexane rings are approximately perpendicular to each other, and the phenyl rings are equatorial. C—H?π and N—H?O intermolecular interactions, as well as C—H?O inter‐ and intramolecular interactions, occur between the molecules. In addition to van der Waals interactions, the water molecule interacts with the pyrimidinetrione ring to stabilize the structure. 相似文献
10.
Ramaiyer Venkatraman Paresh Chandra Ray Frank R. Fronczek 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o633-o635
Hexamethylenetetramine and rac‐trans‐1,2‐cyclohexanedicarboxylic acid crystallize in a 1:1 ratio as a neutral molecular adduct, C6H12N4·C8H12O4. Two dicarboxylic acid molecules and two tetramine molecules form a hydrogen‐bonded ring, in the shape of a rhombus, which lies on a crystallographic twofold axis bisecting the two diacid molecules. The O—H⋯N hydrogen bonds have lengths 2.6808 (19) and 2.6518 (19) Å, and, in each ring, both acid molecules have the same handedness. 相似文献
11.
Vladimir N. Nesterov Elena A. Viltchinskaia 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):872-873
The positions of the C=C double bonds in the title compound, C16H16N4, the subject of some dispute in the literature, have been clearly identified. The cyclohexene ring has a distorted half‐chair conformation and the cyclopentene and cyclopentane rings adopt envelope conformations. The dihedral angles between planar fragments of the cyclohexene and cyclopentene rings and of the cyclohexene and cyclopentane rings are 7.5 (1) and 86.98 (9)°, respectively. In the crystal, intermolecular N—H?N hydrogen bonds link the molecules into infinite chains running in the [10] direction. 相似文献
12.
Goverdhan Mehta Saikat Sen Siddharth Dey 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):o358-o360
In the title compound, C6H12O4·H2O, 1,4/2,5‐cyclohexanetetrol and water molecules are seen to possess twofold symmetry. All four hydroxyl groups of the tetrol participate in extensive intermolecular O—H⋯O hydrogen bonding to form molecular tapes propagating along the a axis. Translationally related tapes along the c axis are held together by four coordinated water molecules. 相似文献
13.
Dmitrii S. Yufit Judith A. K. Howard 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o141-o143
The crystal structures of (1R,1′S)‐2′,2′‐dichloro‐N‐(1‐phenylethyl)cyclopropane‐1′‐carboxamide, C12H13Cl2NO, (I), and (1R,1′R)‐2′,2′‐difluoro‐N‐(1‐phenylethyl)cyclopropane‐1′‐carboxamide, C12H13F2NO, (II), have been determined. Both crystals contain two independent molecules with different conformations of the phenylethyl groups. In the crystals of both compounds, the molecules are linked together by N—H⃛O hydrogen bonds, thus forming chains in the a direction. 相似文献
14.
Brian T. Holmes Clifford W. Padgett William T. Pennington 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o114-o116
The title compound, C34H26N4·2CH2Cl2, lies about an inversion center. The solvent molecules interact with the benzene molecule both through C—H⃛N hydrogen bonding to span pyridine N atoms of adjacent vinyl groups, possibly stabilizing the rotational conformation observed, and through a π interaction between a dichloromethane Cl atom and a pyridyl ring C—C bond of a c‐glide‐related molecule. The benzene molecules form stacks along the a axis such that two of the four olefin groups are properly oriented for photoreactivity (2+2 cyclodimerization). 相似文献
15.
K. SethuSankar S. Banumathi R. Krishna D. Velmurugan 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):e479-e480
In the title compound, C13H16O4, the cyclohexene rings adopt a sofa conformation. Adjacent molecules are connected by C—H?O intermolecular interactions. Each molecule is characterized by O—H?O intramolecular hydrogen bonds. The anti arrangement of the enolic OH group and the carbonyl O atom in the solid state is similar to the anti arrangement of the NH and carbonyl groups in indigo. 相似文献
16.
Boris Shivachev Rosica Petrova Emilia Naydenova 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(8):o524-o526
The title compound [systematic name: 1′‐aminocyclohexanespiro‐4′‐imidazole‐2′,5′(3′H,4′H)‐dione], C8H13N3O2, has been synthesized and was found to crystallize in two different structures, both monoclinic and both with the same P21/c space group. In the first structure, there are two molecules in the asymmetric unit, one of which uses all of its hydrogen‐bond donors and acceptors and forms undulating layers, while the other forms chains propagating perpendicular to the layers. In the second structure, there is only one independent molecule and the packing is based on a chain structure mediated by hydrogen bonding between the hydantoin moieties and further grouped into hydrophilic layers separated by layers of the hydrophobic cyclohexyl groups. 相似文献
17.
S. Thamotharan V. Parthasarathi S. Dubey D. P. Jindal Anthony Linden 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o110-o112
In the title compound, C29H36O2, the outer cyclohexene ring of the steroid nucleus has a conformation that lies about half‐way between a half‐chair and an envelope, while the central and outer cyclohexane rings of the steroid nucleus have slightly distorted chair conformations. The steroidal cyclopentane ring adopts a 13β,14α‐half‐chair conformation. The benzylidene moiety has an E configuration with respect to the carbonyl group on the cyclopentane ring. The dihedral angle between the mean planes of the steroid nucleus and the benzylidene moiety is 35.54 (9)°. The packing of the molecules is assumed to be dictated mainly by weak intermolecular C—H⋯O interactions. 相似文献
18.
Carsten Wieczorrek 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1082-1084
The novel compound bis(1,4,7,10‐tetraoxacyclododecane)cadmium(II) decaiodide, [Cd(C8H16O4)2]I10, contains the [Cd(12‐crown‐4)2]2+ complex cation, triiodide ions and iodine molecules. Two triiodide ions and two iodine molecules form isolated twisted I102? rings. The geometry of the complex cation is as expected, e.g.d(Cd—O) = 2.366 (4) and 2.394 (4) Å. 相似文献
19.
Miao Du Lin‐Hong Weng Xue‐Bing Leng Xian‐He Bu Ruo‐Hua Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1090-1091
The crystal structure of the title complex, [Cd(C20H25N2O2)Cl], reveals a hydrogen‐bonded dimer composed of neutral molecules. The CdII center is five‐coordinated by two O atoms of the pendant arms, two nitrogen donors of the 1,5‐diazacyclooctane ring and a chloride anion. The coordination geometry of the complex could be described as a distorted square pyramid. The 1,5‐diazacyclooctane backbone adopts a boat/chair configuration and the two phenol/phenolato groups have a dihedral angle of 101.3 (2)° between them. The coordinated phenolate and phenolic groups of inversion‐related molecules form strong intermolecular O—H?O hydrogen bonds. 相似文献
20.
Jonglin F. Tsao Sana R. Faruqi Hugh W. Thompson Roger A. Lalancette 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):o57-o59
2,8‐Dioxatricyclo[3.3.3.01,5]undecane‐3,7‐dione, C9H10O4, (I), is the dilactone acylal of cyclopentanone‐2,2‐diacetic acid. Both molecules in the asymmetric unit have conformational chirality and differ principally in the flexing of the carbon ring, which produces a resolvable conformational disorder in one of the molecules. Three intermolecular C—H⋯O close contacts exist. 7,7′‐Oxybis(2,8‐dioxatricyclo[3.3.3.01,5]undecan‐3‐one), C18H22O7, (II), a racemate, lies on a C2 axis and is a non‐meso furanosyl furanoside dimer derived from the monoacid monoaldehyde corresponding to (I). One intermolecular C—H⋯O close contact exists. Diminished intramolecular void space in these small propellanoids generates unusually high crystal density in both species, particularly (I). 相似文献