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1.
A. Bagaria S. Ramakumar M. Gupta V. S. Chauhan 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(3):o174-o176
The title compound (systematic name: 3‐benzylidene‐6‐isobutylpiperazine‐2,5‐dione), C15H18N2O2, an α,β‐dehydrophenylalanine containing diketopiperazine, crystallizes in the space group P1 with two molecules in the asymmetric unit arranged antiparallel to one another. The α,β‐dehydrophenylalanine (ΔPhe) residue in this cyclic peptide retains its planarity but deviates from the standard conformations observed in its linear analogues. Each type of molecule forms a linear chain with molecules of the same type via pairwise N—H⋯O hydrogen bonds, while weaker C—H⋯O interactions link the chains together to form a three‐dimensional network. 相似文献
2.
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
3.
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
4.
Alexander J. Blake Binod B. De Wan‐Sheung Li Neil R. Thomas 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):m570-m574
In the title compounds, [N‐(phenyl{2‐[N‐(S)‐(2‐picolyl)prolylamino]phenyl}methylene)‐(S)‐phenylalaninato]nickel(II), [Ni(C33H30N4O3)], (I), [N‐(phenyl{2‐[N‐(S)‐(3‐picolyl)prolylamino]phenyl}methylene)‐(S)‐phenylalaninato]nickel(II) hemihydrate, [Ni(C33H30N4O3)]·0.5H2O, (II), and [N‐({2‐[N‐(S)‐ethylprolylamino]phenyl}phenylmethylene)‐(S)‐phenylalaninato]nickel(II), [Ni(C29H29N3O3)], (III), the NiII centres have approximate square‐planar coordination geometries from N3O donor sets. The picolyl N atoms in (I) and (II) are too remote from the metal centres to interact significantly, but the metal coordination geometries experience tetrahedral distortion and/or displacement of the metal centre from the N3O plane. These are linked to conformational differences between the ligands of the symmetry‐independent complexes (Z′ = 2), which in turn are related to molecular packing. In (III), where a less sterically demanding ethyl group replaces the picolyl substituents, there are none of the distortions or displacements seen in (I) and (II). 相似文献
5.
Hoong‐Kun Fun S. Kannan Anwar Usman Ibrahim Abdul Razak Suchada Chantrapromma 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(7):m368-m370
In the title compound, [UO2(C15H11O2)2(C14H14OS)], the UVI atom is coordinated by seven O atoms in a distorted pentagonal–bipyramidal geometry. Both diphenylpropane‐1,3‐dionate systems are nearly planar. The sulfoxide moiety is in a distorted tetrahedral geometry, while its two aromatic rings are nearly orthogonal to one another. The crystal packing is stabilized by two bifurcated hydrogen‐bonding interactions involving both uranyl O atoms. 相似文献
6.
A. Subbiah Pandi D. Velmurugan S. Shanmuga Sundara Raj Hoong‐Kun Fun P. R. Seshadri D. Thirumalai 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):821-824
10‐(4‐Fluorophenyl)‐3,3,6,6,9‐pentamethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione, C24H28FNO2, (I), crystallizes with two crystallographically independent molecules (which differ slightly in conformation), while 10‐(4‐fluorophenyl)‐9‐propyl‐3,3,6,6‐tetramethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione, C26H32FNO2, (II), crystallizes with one molecule per asymmetric unit. In both structures, the central ring in the acridine moiety is in a sofa conformation, while the outer rings adopt intermediate half‐chair/sofa conformations. The central pyridine ring is orthogonal to the substituted phenyl ring. In both structures, the packing of the crystal is stabilized by C—H?O intermolecular hydrogen bonds. 相似文献
7.
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
8.
Daniel E. Lynch Ian McClenaghan 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):o1-o5
The crystal structures of four trifluoromethylnitrobenzene analogues (CF3)C6H3(NO2)[C4H8N2]R (where C4H8N2 is piperazinyl and R is ethyl carboxylate, CO2C2H5, or phenyl, C6H5), have been determined, and their conformations and packing arrangements are compared. The four compounds are ethyl 4‐[4‐nitro‐2‐(trifluoromethyl)phenyl]piperazine‐1‐carboxylate, (I), and ethyl 4‐[2‐nitro‐4‐(trifluoromethyl)phenyl]piperazine‐1‐carboxylate, (II), both C14H16F3N3O4, and 1‐[4‐nitro‐2‐(trifluoromethyl)phenyl]‐4‐phenylpiperazine, (III), and 1‐[2‐nitro‐4‐(trifluoromethyl)phenyl]‐4‐phenylpiperazine, (IV), both C17H16F3N3O2. All molecules adopt a rod‐like conformation, while the asymmetric units of (II) and (IV) contain two unique molecules that pack as monodirectional pairs. All molecules pack with C—H⋯O/F close contacts to all but one of the O atoms and to five of the 18 F atoms. 相似文献
9.
Vladimir N. Nesterov Elena A. Viltchinskaia 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):616-618
The structures of the title compounds, C15H13N3O4, (I), and C16H15N3O5 [IUPAC name: ethyl 6‐amino‐5‐cyano‐2‐methyl‐4‐(3‐nitrophenyl)‐4H‐pyrano‐3‐carboxylate], (II), are very similar, with the heterocyclic rings adopting boat conformations. The pseudo‐axial m‐nitrophenyl substituents are rotated by 84.0 (1) and 98.7 (1)° in (I) and (II), respectively, with respect to the four coplanar atoms of the boat. The dihedral angles between the phenyl rings and nitro groups are 12.1 (2) and 8.4 (2)° in (I) and (II), respectively. The two compounds have similar patterns of intermolecular N—H?O and N—H?N hydrogen bonding, which link molecules into infinite tapes along b . 相似文献
10.
S. Kannan S. Shanmuga Sundara Raj Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e545-e546
In the title complex, [UO2(dbm)2(PhSOPh)] or [UO2(C15H11O2)(C12H10OS)], where dbm is 1,3‐diphenylpropane‐1,3‐dionate, the U atom is surrounded by seven O atoms to give a distorted pentagonal bipyramidal geometry. The U—Ouranyl and U—Odbm distances (dbm is 1,3‐diphenylpropane‐1,3‐dionate) are in the ranges 1.760 (6)–1.776 (5) and 2.308 (4)–2.417 (4) Å, respectively, while the U—Osulfoxide distance is 2.427 (4) Å. 相似文献
11.
Katarzyna Stadnicka Pawe Szlachcic 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o129-o131
The reaction of biphenyl‐2,2′‐diol with 1,1,2,2‐tetrakis(bromomethyl)cyclopropane leads to two products, namely a propellane‐type compound and a dispiro‐type compound. The molecular structure of 4,5;6,7‐dibenzo‐3,8,12‐trioxa[8.3.1]propellane has been determined previously by spectroscopic methods. The crystal structure of the dispiro product, 2,7,12,17‐tetraoxa‐3,4:5,6:13,14:15,16‐tetrabenzodispiro[8.1.8.0]nonadecane, C31H26O4, revealed that the conformations of the nine‐membered heterocyclic rings are due to interactions between the π‐electron system of the biphenyl moiety and the lone electron pairs of the ether O atoms, the repulsion of the lone electron pairs of atoms O1⃛O2 and O3⃛O4, and steric interactions between H atoms in ortho positions. The conformations have C1 symmetry and can be described approximately as twist‐boat. 相似文献
12.
A. Subbiah Pandi V. Rajakannan D. Velmurugan Masood Parvez Moon‐Jib Kim A. Senthilvelan S. Narasinga Rao 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o164-o167
N‐(2‐Chlorobenzyl)‐1,2,3,4‐tetrahydroisoquinoline‐1,3‐dione, C16H12ClNO2, crystallizes in P21/n with three crystallographically independent molecules in the asymmetric unit, which differ slightly in conformation, N‐(2‐bromo‐4‐methylphenyl)‐1,2,3,4‐tetrahydroisoquinoline‐1,3‐dione, C16H12BrNO2, crystallizes in P21/n with one molecule in the asymmetric unit andN‐(2,3‐dichlorophenyl)‐1,2,3,4‐tetrahydroisoquinoline‐1,3‐dione, C15H9Cl2NO2, crystallizes in P21/c with one molecule in the asymmetric unit. In all three structures, the heterocyclic rings adopt approximately planar conformations. The pyridine rings are orthogonal to the substituted phenyl rings. In all three structures, the crystal packing is stabilized by intermolecular C—H?O hydrogen bonds. 相似文献
13.
Rebecca R. Conry Orville Green Mohammed Bakir 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o607-o609
A new polymorph of di‐2‐pyridyl ketone 4‐nitrophenylhydrazone [alternative name: N‐(dipyridin‐2‐ylmethylene)‐N′‐(4‐nitrophenyl)hydrazine], C17H13N5O2, isolated from the filtrate of a sonicated acetonitrile solution of dpknph and CdCl2, was found to crystallize in the monoclinic space group P21/c, in contrast to the known form which crystallizes in P21/n. The non‐coplanar molecules pack in parallel stacks without any intermolecular hydrogen‐bonding interactions. This packing pattern contrasts with the interlocked interdigitated packing seen in the previously known polymorph. 相似文献
14.
John Nicolson Low Justo Cobo Manuel Nogueras Adolfo Snchez Braulio Insuasty Harlen Torres 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):o39-o41
2,2‐Dimethyl‐5‐[3‐(4‐methylphenyl)‐2‐propenylidene]‐1,3‐dioxane‐4,6‐dione, C16H16O4, crystallizes in the triclinic space group , with two molecules in the asymmetric unit. These molecules and a centrosymmetrically related pair, linked together by weak C—H?O hydrogen bonds, form a tetramer. 5‐[3‐(4‐Chlorophenyl)‐2‐propenylidene]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione, C15H13ClO4, also crystallizes in the triclinic space group , with one molecule in the asymmetric unit. Centrosymmetrically related molecules are linked together by weak C—H?O hydrogen bonds to form dimers which are further linked by yet another pair of centrosymmetrically related C—H?O hydrogen bonds to form a tube which runs parallel to the a axis. 相似文献
15.
Carl Henrik Grbitz 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1496-1498
One of the amino H atoms of l ‐phenylalanyl‐l ‐valine, C14H20N2O3, participates in a rare secondary interaction in being accepted by the aromatic ring of the phenylalanine side chain. The phenyl group is also a donor in a weak hydrogen bond to the peptide carbonyl group. 相似文献
16.
17.
S. Renganayaki E. Subramanian S. Shanmuga Sundara Raj Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):349-350
The aromatic ring of the cinnamic moiety in N‐benzyl‐2′‐iodocinnamanilide, C22H18INO, (I), and N‐benzyl‐2′‐iodo‐4′‐methyl‐2‐phenylcinnamanilide, C29H24INO, (II), makes a dihedral angle with the iodophenyl ring of 72.1 (2) and 81.0 (2)° in (I) and (II), respectively. In (I), molecules exist as discrete components, while in (II), they form infinite chains along the b axis, through I?O non‐bonded interactions. 相似文献
18.
Bernardo Masci Stefano Levi Mortera Maurizio Varrone Pierre Thury 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o649-o651
Two compounds containing 1,3‐benzodioxin groups are reported, namely (±)‐6‐tert‐butyl‐8‐hydroxymethyl‐2‐phenyl‐4H‐1,3‐benzodioxin, C19H22O3, (I), and 2,2,2′,2′,6,6′‐hexamethyl‐8,8′‐methylenebis(4H‐1,3‐benzodioxin), C23H28O4, (II).The hydroxy groups of neighbouring molecules in (I) are hydrogen bonded to each other, giving rise to double‐row chains. The molecule in (II) adopts a `butterfly' conformation, with the O atoms in distal positions. In both compounds, the dioxin rings are in distorted half‐chair conformations. 相似文献
19.
Andrzej Domaski Krzysztof Ejsmont Janusz B. Kyzio Jacek Zaleski 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):467-470
Two isomeric trans‐4‐aminoazoxybenzenes, trans‐1‐(4‐aminophenyl)‐2‐phenyldiazene 2‐oxide (α, C12H11N3O) and trans‐2‐(4‐aminophenyl)‐1‐phenyldiazene 2‐oxide (β, C12H11N3O), have been characterized by X‐ray diffraction. The α isomer is almost planar, having torsion angles along the Caryl—N bonds of only 4.9 (2) and 8.0 (2)°. The relatively short Caryl—N bond to the non‐oxidized site of the azoxy group [1.401 (2) Å], together with the significant quinoid deformation of the respective phenyl ring, is evidence of conjugation between the aromatic sextet and the π‐electron system of the azoxy group. The geometry of the β isomer is different. The non‐substituted phenyl ring is twisted with respect to the NNO plane by ca 50°, whereas the substituted ring is almost coplanar with the NNO plane. The non‐oxidized N atom in the β isomer has increased sp3 character, which leads to a decrease in the N—N—C bond angle to 116.8 (2)°, in contrast with 120.9 (1)° for the α isomer. The deformation of the C—C—C angles (1–2°) in the phenyl rings at the substitution positions is evidence of the different character of the oxidized and non‐oxidized N atoms of the azoxy group. In the crystal structures, molecules of both isomers are arranged in chains connected by weak N—H?O (α and β) and N—H?N (β) hydrogen bonds. 相似文献
20.
Boris Shivachev Rosica Petrova Petja Marinova Neyko Stoyanov Anife Ahmedova Mariana Mitewa 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(4):o211-o215
The crystal structures of four cycloalkanespiro‐4′‐imidazolidine‐2′,5′‐dithiones, namely cyclopentanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.4]nonane‐2,4‐dithione}, C7H10N2S2, cyclohexanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.5]decane‐2,4‐dithione}, C8H12N2S2, cycloheptanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.6]undecane‐2,4‐dithione}, C9H14N2S2, and cyclooctanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.7]dodecane‐2,4‐dithione}, C10H16N2S2, have been determined. The three‐dimensional packing in all of the structures is based on closely similar chains, in which hydantoin moieties are linked through N—H⋯S hydrogen bonding. The size of the cycloalkane moiety influences the degree of its deformation. In the cyclooctane compound, the cyclooctane ring assumes both boat–chair and boat–boat conformations. 相似文献