共查询到20条相似文献,搜索用时 10 毫秒
1.
Xiu‐Li You Cheng‐Rong Lu Yong Zhang De‐Chun Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o693-o695
Molecular packing analyses were carried out on 15 crystal data sets of chloro‐substituted Schiff bases, including that of the title compound, C15H15ClN2. C—H⋯π and π–π interactions play a major role in the molecular self‐assembly in the crystal. The former interactions favor molecules assembling into a screw, with a non‐centrosymmetric crystal structure. When the molecular dipole is small, π–π interactions favor a parallel, but not usually antiparallel, mode of packing. Weak C—H⋯X hydrogen bonds (X = Cl or Br) and X⋯X interactions seem to be a secondary driving force in packing. The title molecule takes the trans form and the two benzene rings are twisted around the central linkage in opposite directions. In the crystal structure, molecules interact through C—H⋯π and π–π interactions, forming a `dimer' and further forming double chains along [001]. The double chains are extended along [10] through C—H⋯Cl hydrogen bonds, forming double layers in (010). In the third direction, there are only ordinary, weaker, van der Waals interactions, which explains the crystal habit (i.e. thin plate). 相似文献
2.
Alexander S. Romanov Gary F. Angles Mikhail Yu. Antipin Tatiana V. Timofeeva 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(3):m69-m72
The structures of tricarbonyl(formylcyclopentadienyl)manganese(I), [Mn(C6H5O)(CO)3], (I), and tricarbonyl(formylcyclopentadienyl)rhenium(I), [Re(C6H5O)(CO)3], (II), were determined at 100 K. Compounds (I) and (II) both possess a carbonyl group in a trans position relative to the substituted C atom of the cyclopentadienyl ring, while the other two carbonyl groups are in almost eclipsed positions relative to their attached C atoms. Analysis of the intermolecular contacts reveals that the molecules in both compounds form stacks due to short attractive π(CO)...π(CO) and π(CO)...π interactions, along the crystallographic c axis for (I) and along the [201] direction for (II). Symmetry‐related stacks are bound to each other by weak intermolecular C—H...O hydrogen bonds, leading to the formation of the three‐dimensional network. 相似文献
3.
Qi Zhou Lina Zhang Haruyuki Okamura Masahiko Minoda Takeaki Miyamoto 《Journal of polymer science. Part A, Polymer chemistry》2001,39(3):376-382
In this article, a series of O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl celluloses with different degree of substitution (DS) values was synthesized by a homogeneous reaction of cellulose with 2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl chloride in a 10% (w/w) dimethylacetamide/lithium chloride solution, combined with pyridine as the acid acceptor. The total DS values of the derivatives in anhydroglucose units was determined by 1H and 13C NMR spectra, and ranged from 0.4 to 3.0, depending on the amount of acid chloride in the reaction. The effects of the total DS values and the O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl substituent distribution on the solubility of the derivatives were investigated. The lowest limit of the DS value for water‐soluble O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl cellulose was approximately 0.5, which is lower than that of methylcellulose. The amphiphilic derivatives with higher DS values than 1.7 exhibited a good solubility in both water and organic solvents, such as dimethyl sulfoxide, tetrahydrofuran, and chloroform. Sol‐gel transition in aqueous solution was observed for the amphiphilic derivatives with a higher DS value than 1.7; the precipitation temperature (Tp) decreased as the DS value increased, showing that the derivatives are highly temperature sensitive. The thermal properties of the fully substituted derivative were measured using polarized microscopy, DSC, and X‐ray diffraction; and are discussed in terms of phase transition of the sample derivatives. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 376–382, 2001 相似文献
4.
Moon‐Gun Choi Robert J. Angelici 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):808-810
In the title compound, [W(C5H5NS)(CO)5], the pyridine‐4‐thiol ligand coordinates through the sulfur in the thione mode. The coordination sphere around the W atom is distorted from octahedral geometry by intermolecular hydrogen bonding and steric interactions between the pyridine ring and two CO ligands. An intermolecular pyridine–pyridine ring distance of 3.47 (1) Å indicates π–π stacking interactions between these ligand units. 相似文献
5.
Chang‐Kun Xia Quan‐Zheng Zhang Shu‐Mei Chen Xiang He Can‐Zhong Lu 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):m203-m205
The title compound, (C12H11N3)2[Cd2Cl8], consists of two discrete 2‐(3‐pyridinio)benzimidazolium cations and one [Cd2Cl8]4− anion. The dimeric [Cd2Cl8]4− anion lies about an inversion centre and consists of two distorted [CdCl5] trigonal bipyramids which share a common edge. The two Cd atoms are each coordinated by two μ‐Cl atoms and three terminal Cl atoms, with a Cd·Cd separation of 3.9853 (6) Å. The packing displays two‐dimensional hydrogen‐bonded sheets, which are further linked by C—H·Cl contacts and π–π stacking interactions to yield a three‐dimensional network. 相似文献
6.
Miquel Barcel‐Oliver Angel Terrn Angel García‐Raso Nina Lah Iztok Turel 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(6):o313-o316
The title compound, C20H17N3, is a derivative of 1,3,5‐triaryl‐2‐pyrazoline and can act as an N,N′‐bidentate ligand. This molecule features strong fluorescence that can be explained by an extended pyridyl–C=N—N–phenyl system. The three‐dimensional structure is formed by means of an extended network of weak C—H...π hydrogen bonds supported by π–π interactions. 相似文献
7.
Bi‐Yun Su Jia‐Xiang Wang Xiang Liu Qian‐Ding Li 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):522-525
The title isomers, namely 3‐chloro‐N‐[1‐(1H‐pyrrol‐2‐yl)ethylidene]aniline, (I), and 4‐chloro‐N‐[1‐(1H‐pyrrol‐2‐yl)ethylidene]aniline, (II), both C12H11ClN2, differ in the position of the chlorine substitution. Both compounds have the basic iminopyrrole structure, which shows a planar backbone with similar features. The dihedral angle formed by the planes of the pyrrole and benzene rings is 75.65 (7)° for (I) and 86.56 (8)° for (II). The H atom bound to the pyrrole N atom is positionally disordered and partial protonation occurs at the imino N atom in (I), while this phenomenon is absent from the structure of (II). Packing interactions for both compounds include intermolecular N—H...N hydrogen bonds and C—H...π interactions, forming centrosymmetric dimers for both (I) and (II). 相似文献
8.
Dan Jin Zhao‐Fu Dai De‐Chun Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(2):o50-o52
In the title compound, C15H16NO+·C24H20B−, the pyridinium ring of the cation makes a dihedral angle of 4.3 (2)° with the benzene ring. Each is rotated in the same direction with respect to the central C—CH=CH—C linkage, by 10.0 (2) and 7.8 (2)°, respectively. The anions have a slightly distorted tetrahedral geometry. The most interesting feature of the structure is that the anions form a honeycomb‐like hexagonal structure down the b axis through C—H...π interactions. The hexagon is constructed from six BPh4− anions. The cations interact in a head‐to‐tail fashion along [010], forming chains, and pack antiparallel inside the above honeycomb‐like structure through C—H...π interactions. 相似文献
9.
Philip J. Cox Stephen M. MacManus 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):o603-o604
Molecules of the title compound, C13H9ClO2, contain an intramolecular O—H...O hydrogen bond, and the two aromatic rings are inclined at 57.02 (3)° with respect to one another. The crystal structure is supported by C—H...O, C—H...π and π–π interactions. 相似文献
10.
Mohamed Abboud Amal Kadimi Victor Mamane Emmanuel Aubert 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(7):o381-o384
The crystal packing of the title compound, C17H9Br2ClN2O, is governed by strong π–π stacking, where molecules are tightly bound within infinite (100) planes; these planes interact mainly through non‐optimal π–π stacking where arene rings are noticeably displaced from perfect overlap, and also through halogen–halogen interactions. The aldehyde group shows conformational disorder, with a significant population difference between the two conformers; this difference is rationalized by the energetic analysis of the crystal packing using the PIXEL method, which also allows a decomposition of intermolecular interaction energy into Coulombic, polarization, dispersion and repulsion contributions. Using such an analysis, it is found that the main reason for this unequal population of the two conformers in the crystal is two hydrogen bonds that are present only for the major conformer. 相似文献
11.
Alberto Insuasty Braulio Insuasty Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(1):74-76
The molecules of the title compound, C17H21N3OS, are characterized by a wide C—C—C angle at the methine C atom linking the aryl and thiazolidine rings, associated with a short repulsive intramolecular S...H contact between atoms in these two rings. A single piperidine–arene C—H...π hydrogen bond links pairs of molecules into centrosymmetric dimers. 相似文献
12.
Rosana S. Montani Raúl O. Garay Fabio D. Cukiernik Maria T. Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(3):o81-o84
The crystal structure of the dimeric title compound, C19H22O5, is dominated by a head‐to‐head hydrogen‐bonding interaction between centrosymmetrically related carboxyl groups in each monomer. The result is a dimeric axis of unusual length (ca 34 Å), but still shorter than what could be expected for a fully extended chain, owing to two turning points in the oligoethoxy ends. This allows for an explanation of the structure of the smectic mesophase exhibited by this compound and at the same time fully validates former geometric estimations based on PM3 calculations. 相似文献
13.
Alexander J. Blake Peter Hubberstey Alexander D. Mackrell Claire Wilson 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):o293-o297
The trans–trans conformations adopted by the derivatized bis(bidentate) chelating N4‐donor ligand 3,6‐bis(pyrazol‐1‐yl)‐4‐[2‐(4‐thiamorpholino)ethanesulfanyl]pyridazine, C16H19N7S2, and an intermediate in its formation, 3,6‐dichloro‐4‐[2‐(4‐thiamorpholino)ethanesulfanyl]pyridazine, C10H13Cl2N3S2, contrast with the cis–cis conformation found previously for 3,6‐bis(thiophen‐2‐yl)pyridazine [Ackers, Blake, Hill & Hubberstey (2002). Acta Cryst. C 58 , o640–o641], which places all four heteroatoms on the same side of the molecule. 相似文献
14.
Shu‐Jin Li De‐Chun Zhang Zhong‐Lin Huang Yan‐Qiu Zhang Kai‐Bei Yu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1122-1123
In the cation of the title compound, C15H16NO+·C24H20B?, the pyridyl ring makes a dihedral angle of 14.03° with the phenyl ring. The anion has a slightly distorted tetrahedral geometry and forms honeycomb‐like sheets which extend along the b axis, forming channels containing the cations. A comparison of packing energies reveals a difference between the title compound and a similar material which has non‐linear optical properties. 相似文献
15.
Katherine E. Washington Ruvanthi N. Kularatne Jia Du Matthew J. Gillings Jack C. Webb Nicolette C. Doan Michael C. Biewer Mihaela C. Stefan 《Journal of polymer science. Part A, Polymer chemistry》2016,54(22):3601-3608
Linear and star‐like amphiphilic diblock copolymers were synthesized by the ring‐opening polymerization of ε‐caprolactone and γ‐2‐[2‐(2‐methoxyethoxy)ethoxy]ethoxy‐ε‐caprolactone monomers using zinc undecylenate as a catalyst. These polymers have potential applications as micellar drug delivery vehicles, therefore the properties of the linear and 4‐arm star‐like structures were examined in terms of their molecular weight, viscosity, thermodynamic stability, size, morphology, and drug loading capacity. Both the star‐like and linear block copolymers showed good thermodynamic stability and degradability. However, the star‐like polymers were shown to have increased stability at lower concentrations with a critical micelle concentration (CMC) of 5.62 × 10?4 g L?1, which is less than half the concentration of linear polymer needed to form micelles. The star‐like polymeric micelles showed smaller sizes when compared with their linear counterparts and a higher drug loading capacity of doxorubicin, making them better suited for drug delivery purposes. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3601–3608 相似文献
16.
Bin Li Hai‐Bin Song Chi‐Tung Hsu Ke‐Liang Zhang Chao Wu Hua‐Zheng Yang 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):o114-o117
The molecular structures of 2‐[4‐chloro‐2‐fluoro‐5‐(prop‐2‐ynyloxy)phenyl]‐1,3,4,5,6,7‐hexahydroisoindole‐1,3‐dione, C17H13ClFNO3, (I), and the isomeric compound 2‐[4‐chloro‐2‐fluoro‐5‐(prop‐2‐ynyloxy)phenyl]‐cis‐1,3,3a,4,7,7a‐hexahydroisoindole‐1,3‐dione, (II), are, as anticipated, significantly different in their conformations and in the distances between the farthest two atoms. The six‐membered ring of the 1,3,4,5,6,7‐hexahydroisoindole‐1,3‐dione moiety in (I) adopts a half‐chair conformation. The dihedral angle between the five‐membered dione ring of (I) and the benzene ring is 50.96 (7)°. The six‐membered ring of the cis‐1,3,3a,4,7,7a‐hexahydroisoindole‐1,3‐dione moiety in (II) adopts a boat conformation. The dihedral angle in (II) between the five‐membered dione ring and the benzene ring is 61.03 (13)°. In the crystal structures, the molecules are linked by C—H⋯O hydrogen bonds and weak π–π interactions. Compound (I) is a much more potent herbicide than (II). The Cl⋯H distances between the farthest two atoms in (I) and (II) are 11.37 and 9.97 Å, respectively. 相似文献
17.
Jazmin E. Gonzlez‐Padilla Martha C. Rosales‐Hernndez Itzia I. Padilla‐Martínez Efren V. García‐Bez Susana Rojas‐Lima Veronica Salazar‐Pereda 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):55-59
Molecules of 1,2‐bis(4‐bromophenyl)‐1H‐benzimidazole, C19H12Br2N2, (I), and 2‐(4‐bromophenyl)‐1‐(4‐nitrophenyl)‐1H‐benzimidazole, C19H12BrN3O2, (II), are arranged in dimeric units through C—H...N and parallel‐displaced π‐stacking interactions favoured by the appropriate disposition of N‐ and C‐bonded phenyl rings with respect to the mean benzimidazole plane. The molecular packing of the dimers of (I) and (II) arises by the concurrence of a diverse set of weak intermolecular C—X...D (X = H, NO2; D = O, π) interactions. 相似文献
18.
Soumen Ghosh Rupa Mukhopadhyay Madeleine Helliwell Alok K. Mukherjee 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(8):o496-o500
The pyrazine ring in two N‐substituted quinoxaline derivatives, namely (E)‐2‐(2‐methoxybenzylidene)‐1,4‐di‐p‐tosyl‐1,2,3,4‐tetrahydroquinoxaline, C30H28N2S2O5, (II), and (E)‐methyl 2‐[(1,4‐di‐p‐tosyl‐1,2,3,4‐tetrahydroquinoxalin‐2‐ylidene)methyl]benzoate, C31H28N2S2O6, (III), assumes a half‐chair conformation and is shielded by the terminal tosyl groups. In the molecular packing of the compounds, intermolecular C—H...O hydrogen bonds between centrosymmetrically related molecules generate dimeric rings, viz. R22(22) in (II) and R22(26) in (III), which are further connected through C—H...π(arene) hydrogen bonds and π–π stacking interactions into novel supramolecular frameworks. 相似文献
19.
K. Sethu Sankar S. Kannadasan D. Velmurugan P. C. Srinivasan S. Shanmuga Sundara Raj H.‐K. Fun 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):o277-o279
The title compound, C28H27N3O4S, crystallizes in the centrosymmetric space group P21/n, with one molecule in the asymmetric unit. In the indole ring, the dihedral angle between the fused rings is 3.6 (1)°. The phenyl ring of the sulfonyl substituent makes a dihedral angle of 79.2 (1)° with the best plane of the indole moiety. The phenyl ring of the dimethylaminophenyl group is orthogonal to the phenyl ring of the phenylsulfonyl group. The dihedral angle formed by the weighted least‐squares planes through the pyrrole ring and the phenyl ring of the dimethylaminophenyl group is 7.8 (1)°. The molecular structure is stabilized by C—H?O and C—H?N interactions. 相似文献
20.
A series of new polyamides containing both sulfone and oxyethylene moieties in the polymer chain was prepared by the direct polycondensation of the diamine monomer 2,2‐bis[4‐[2‐(4‐aminophenoxy)ethoxy]phenyl]sulfone (BAEPS) and various aromatic dicarboxylic acids in N‐methyl‐2‐pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. Polymers were produced with inherent viscosities of 0.30–0.60 dl/g and identified by elemental analysis, and infrared and nuclear magnetic resonance spectra. Most of the polymers were readily dissolved in polar solvents such as NMP, dimethylsulfoxide, N,N‐dimethylacetamide, N,N‐dimethylformamide and m‐cresol at room temperature. Polymers containing rigid and symmetric p‐phenylene, naphthalene and p‐biphenylene moieties revealed a crystalline nature and showed no solubility in organic solvents. These polyamides had 10% weight loss temperatures ranging between 423 and 465 °C in nitrogen atmosphere and glass transition temperatures between 170 and 305 °C. The polymers with crystallinity nature exhibited melting endotherms (Tm) below 386 °C in differential scanning calorimetry trace. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献