共查询到20条相似文献,搜索用时 710 毫秒
1.
Graeme J. Gainsford M. Delower H. Bhuiyan Andrew J. Kay 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(11):o616-o619
The planar component of 2‐{3‐cyano‐4‐[3‐(1‐decyl‐1,4‐dihydroquinolin‐4‐ylidene)prop‐1‐enyl]‐5,5‐dimethyl‐2,5‐dihydrofuran‐2‐ylidene}malononitrile, C32H46N4O, (I), forms into layers parallel to the (01) plane. The larger of the two spaces between layers is filled by the alkyl chains, giving a `sandwich stack' appearance. The packing of 2‐{3‐cyano‐4‐[5‐(1‐decyl‐1,4‐dihydroquinolin‐4‐ylidene)penta‐1,3‐dienyl]‐5,5‐dimethyl‐2,5‐dihydrofuran‐2‐ylidene}malononitrile, C34H38N4O, (II), which has partial disorder in the 1‐decyl group, utilizes weak C—H...N, C—H...O and C—N...π interactions in a three‐dimensional `herring‐bone' array with molecular segments parallel to the (111) and (1) planes. Different rotational isomers with respect to the polyene chain and the 5,5‐dimethyl‐2,5‐dihydrofuran‐2‐ylidene link are observed in the two structures. The significance of the study lies in the delocalization of charge along the polyene chain and the supramolecular aggregation present, which highlight the difficulty in obtaining the noncentrosymmetric alignment required for high nonlinear optical (NLO) responses in zwitterionic chromophores. 相似文献
2.
Graeme J. Gainsford M. Delower H. Bhuiyan Andrew J. Kay 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(4):o195-o198
The compounds N‐[2‐(4‐cyano‐5‐dicyanomethylene‐2,2‐dimethyl‐2,5‐dihydrofuran‐3‐yl)vinyl]‐N‐phenylacetamide, C20H16N4O2,(I), and 2‐{3‐cyano‐5,5‐dimethyl‐4‐[2‐(piperidin‐1‐yl)vinyl]‐2,5‐dihydrofuran‐2‐ylidene}malononitrile 0.376‐hydrate, C17H18N4O·0.376H2O, (II), are novel push–pull molecules. The significant bonding changes in the polyene chain compared with the parent molecule 2‐dicyanomethylene‐4,5,5‐trimethyl‐2,5‐dihyrofuran‐3‐carbonitrile are consistent with the relative electron‐donating properties of the acetanilido and piperidine groups. The packing of (I) utilizes one phenyl–cyano C—H...N and two phenyl–carbonyl C—H...O hydrogen bonds. Compound (II) crystallizes with a partial water molecule (0.376H2O), consistent with cell packing that is dominated by attractive C—H...N(cyano) interactions. These compounds are precursors to novel nonlinear optical chromophores, studied to assess the impact of donor strength and the extent of conjugation on bond‐length alternation, crystal packing and aggregation. 相似文献
3.
Ivan Poto
k Jn Imrich Ivan Danihel Jozef Koíek Karel Douglas Klika 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(2):o87-o92
Two methyl derivatives, five‐membered methyl 2‐{2‐[2‐(9,10‐dihydroacridin‐9‐ylidene)‐1‐methylhydrazinyl]‐4‐oxo‐4,5‐dihydro‐1,3‐thiazol‐5‐ylidene}acetate, C20H16N4O3S, (I), and six‐membered 2‐[2‐(9,10‐dihydroacridin‐9‐ylidene)‐1‐methylhydrazinyl]‐4H‐1,3‐thiazin‐4‐one, C18H14N4OS, (II), were prepared by the reaction of the N‐methyl derivative of 4‐(9,10‐dihydroacridin‐9‐ylidene)thiosemicarbazide, C14H12N4S, (III), with dimethyl acetylenedicarboxylate and methyl propiolate, respectively. The crystal structures of (I), (II) and (III) are molecular and can be considered in two parts: (i) the nearly planar acridine moiety and (ii) the singular heterocyclic ring portion [thiazolidine for (I) and thiazine for (II)] including the linking amine and imine N atoms and the methyl C atom, or the full side chain in the case of (III). The structures of (I) and (II) are stabilized by N—H...O hydrogen bonds and different π–π interactions between acridine moieties and thiazolidine and thiazine rings, respectively. 相似文献
4.
Lina M. Acosta Andrs F. Yepes Alirio Palma Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):162-171
In each of ethyl N‐{2‐amino‐5‐formyl‐6‐[methyl(phenyl)amino]pyrimidin‐4‐yl}glycinate, C16H19N5O3, (I), N‐{2‐amino‐5‐formyl‐6‐[methyl(phenyl)amino]pyrimidin‐4‐yl}glycinamide, C14H16N6O2, (II), and ethyl 3‐amino‐N‐{2‐amino‐5‐formyl‐6‐[methyl(phenyl)amino]pyrimidin‐4‐yl}propionate, C17H21N5O3, (III), the pyrimidine ring is effectively planar, but in each of methyl N‐{2‐amino‐6‐[benzyl(methyl)amino]‐5‐formylpyrimidin‐4‐yl}glycinate, C16H19N5O3, (IV), ethyl 3‐amino‐N‐{2‐amino‐6‐[benzyl(methyl)amino]‐5‐formylpyrimidin‐4‐yl}propionate, C18H23N5O3, (V), and ethyl 3‐amino‐N‐[2‐amino‐5‐formyl‐6‐(piperidin‐4‐yl)pyrimidin‐4‐yl]propionate, C15H23N5O3, (VI), the pyrimidine ring is folded into a boat conformation. The bond lengths in each of (I)–(VI) provide evidence for significant polarization of the electronic structure. The molecules of (I) are linked by paired N—H...N hydrogen bonds to form isolated dimeric aggregates, and those of (III) are linked by a combination of N—H...N and N—H...O hydrogen bonds into a chain of edge‐fused rings. In the structure of (IV), molecules are linked into sheets by means of two hydrogen bonds, both of N—H...O type, in the structure of (V) by three hydrogen bonds, two of N—H...N type and one of C—H...O type, and in the structure of (VI) by four hydrogen bonds, all of N—H...O type. Molecules of (II) are linked into a three‐dimensional framework structure by a combination of three N—H...O hydrogen bonds and one C—H...O hydrogen bond. 相似文献
5.
Frank Strübe Jochen Mattay Beate Neumann Hans‐Georg Stammler 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(1):o33-o36
Fulgides are a representative class of photochromic organic molecules which exhibit several interesting properties for diverse applications in fields such as data storage or high‐resolution spectroscopy. The crystal structures of three furyl fulgides with different steric constraints were determined and for two of the compounds both the E and Z isomer structures were defined. The compounds are 3‐[(E)‐1,3‐dimethyl‐4,5,6,7‐tetrahydro‐2‐benzofuran‐4‐ylidene]‐4‐isopropylidenetetrahydrofuran‐2,5‐dione, C17H18O4, (I‐E), 3‐[(E)‐1,3‐dimethyl‐5,6,7,8‐tetrahydro‐4H‐cyclohepta[c]furan‐4‐ylidene]‐4‐isopropylidenetetrahydrofuran‐2,5‐dione, C18H20O4, (II‐E), and the Z isomer, (II‐Z), and 3‐isopropylidene‐4‐[(E)‐1‐(5‐methoxy‐2‐methyl‐1‐benzofuran‐3‐yl)ethylidene]tetrahydrofuran‐2,5‐dione, C19H18O5, (III‐E), with two molecules in the asymmetric unit, and the Z isomer, (III‐Z). The structures of the E and Z isomers show only little differences in the bond lengths and angles inside the hexatriene unit. Because of the strained geometry there are deviations in the torsion angles. Furthermore, small differences in the distances between the bond‐forming C atoms in the electrocyclization process give no explanation for the unequal photochromic behaviour. 相似文献
6.
Nobuyuki Matsushita Ayako Taira 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(12):1033-1036
The title compound, catena‐poly[[[bis(ethylenediamine‐κ2N,N′)platinum(II)]‐ μ‐chlorido‐[bis(ethylenediamine)platinum(IV)]‐μ‐chlorido] tetrakis{4‐[(4‐hydroxyphenyl)diazenyl]benzenesulfonate} dihydrate], {[PtIIPtIVCl2(C2H8N2)4](HOC6H4N=NC6H4SO3)4·2H2O}n, has a linear chain structure composed of square‐planar [Pt(en)2]2+ (en is ethylenediamine) and elongated octahedral trans‐[PtCl2(en)2]2+ cations stacked alternately, bridged by Cl atoms, along the b axis. The Pt atoms are located on an inversion centre, while the Cl atoms are disordered over two sites and form a zigzag ...Cl—PtIV—Cl...PtII... chain, with a PtIV—Cl bond length of 2.3140 (14) Å, an interatomic PtII...Cl distance of 3.5969 (15) Å and a PtIV—Cl...PtII angle of 170.66 (6)°. The structural parameter indicating the mixed‐valence state of the Pt atom, expressed by δ = (PtIV—Cl)/(PtII...Cl), is 0.643. 相似文献
7.
Jan W. Bats Peter Schell Joachim W. Engels 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):529-533
Crystal structures are reported for three substituted 1H‐imidazole‐4,5‐dicarbonitrile compounds used as catalysts for the coupling reaction of nucleoside methyl phosphonamidites, namely 2‐(3′,5′‐dimethylbiphenyl‐2‐yl)‐1H‐imidazole‐4,5‐dicarbonitrile, C19H14N4, (I), 2‐(2′,4′,6′‐trimethylbiphenyl‐2‐yl)‐1H‐imidazole‐4,5‐dicarbonitrile, C20H16N4, (II), and 2‐[8‐(3,5‐dimethylphenyl)naphthalen‐1‐yl]‐1H‐imidazole‐4,5‐dicarbonitrile, C23H16N4, (III). The asymmetric unit of (I) contains two independent molecules with similar conformations. There is steric repulsion between the imidazole group and the terminal phenyl group in all three compounds, resulting in the nonplanarity of the molecules. The naphthalene group of (III) shows significant deviation from planarity. The C—N bond lengths in the imidazole rings range from 1.325 (2) to 1.377 (2) Å. The molecules are connected into zigzag chains by intermolecular N—H...Nimidazole [for (I)] or N—H...·Ncyano [for (II) and (III)] hydrogen bonds. 相似文献
8.
Paul V. Bernhardt Nathan L. Kilah 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(5):m245-m249
The pendent‐arm macrocyclic hexaamine trans‐6,13‐dimethyl‐1,4,8,11‐tetraazacyclotetradecane‐6,13‐diamine (L) may coordinate in tetra‐, penta‐ or hexadentate modes, depending on the metal ion and the synthetic procedure. We report here the crystal structures of two pseudo‐octahedral cobalt(III) complexes of L, namely sodium trans‐cyano(trans‐6,13‐dimethyl‐1,4,8,11‐tetraazacyclotetradecane‐6,13‐diamine)cobalt(III) triperchlorate, Na[Co(CN)(C13H30N6)](ClO4)3 or Na{trans‐[CoL(CN)]}(ClO4)3, (I), where L is coordinated as a pentadentate ligand, and trans‐dicyano(trans‐6,13‐dimethyl‐1,4,8,11‐tetraazacyclotetradecane‐6,13‐diamine)cobalt(III) trans‐dicyano(trans‐6,13‐dimethyl‐1,4,8,11‐tetraazacyclotetradecane‐6,13‐diaminium)cobalt(III) tetraperchlorate tetrahydrate, [Co(CN)2(C14H32N6)][Co(CN)2(C14H30N6)](ClO4)4·4H2O or trans‐[CoL(CN)2]trans‐[Co(H2L)(CN)2](ClO4)4·4H2O, (II), where the ligand binds in a tetradentate mode, with the remaining coordination sites being filled by C‐bound cyano ligands. In (I), the secondary amine Co—N bond lengths lie within the range 1.944 (3)–1.969 (3) Å, while the trans influence of the cyano ligand lengthens the Co—N bond length of the coordinated primary amine [Co—N = 1.986 (3) Å]. The Co—CN bond length is 1.899 (3) Å. The complex cations in (II) are each located on centres of symmetry. The Co—N bond lengths in both cations are somewhat longer than in (I) and span a narrow range [1.972 (3)–1.982 (3) Å]. The two independent Co—CN bond lengths are similar [1.918 (4) and 1.926 (4) Å] but significantly longer than in the structure of (I), again a consequence of the trans influence of each cyano ligand. 相似文献
9.
Malitsatsi J. Mnguni Andreas Lemmerer 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(2):103-109
Six derivatives of 4‐amino‐1,5‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐3‐one (4‐aminoantipyrine), C11H13N3O, (I), have been synthesized and structurally characterized to investigate the changes in the observed hydrogen‐bonding motifs compared to the original 4‐aminoantipyrine. The derivatives were synthesized from the reactions of 4‐aminoantipyrine with various aldehyde‐, ketone‐ and ester‐containing molecules, producing (Z)‐methyl 3‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]but‐2‐enoate, C16H19N3O3, (II), (Z)‐ethyl 3‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]but‐2‐enoate, C17H21N3O3, (III), ethyl 2‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]cyclohex‐1‐enecarboxylate, C20H25N3O3, (IV), (Z)‐ethyl 3‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]‐3‐phenylacrylate, C22H23N3O3, (V), 2‐cyano‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, C14H14N4O2, (VI), and (E)‐methyl 4‐{[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]methyl}benzoate, C20H19N3O3, (VII). The asymmetric units of all these compounds have one molecule on a general position. The hydrogen bonding in (I) forms chains of molecules via intermolecular N—H...O hydrogen bonds around a crystallographic sixfold screw axis. In contrast, the formation of enamines for all derived compounds except (VII) favours the formation of a six‐membered intramolecular N—H...O hydrogen‐bonded ring in (II)–(V) and an intermolecular N—H...O hydrogen bond in (VI), whereas there is an intramolecular C—H...O hydrogen bond in the structure of imine (VII). All the reported compounds, except for (II), feature π–π interactions, while C—H...π interactions are observed in (II), C—H...O interactions are observed in (I), (III), (V) and (VI), and a C—O...π interaction is observed in (II). 相似文献
10.
Musa A. Said Adeeb Al‐Sheikh Ali David L. Hughes 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(12):1037-1041
Podand‐type ligands are an interesting class of acyclic ligands which can form host–guest complexes with many transition metals and can undergo conformational changes. Organic phosphates are components of many biological molecules. A new route for the synthesis of phosphate esters with a retained six‐membered ring has been used to prepare 2,2′‐[benzene‐1,2‐diylbis(oxy)]bis(5,5‐dimethyl‐1,3,2‐dioxaphosphinane) 2,2′‐dioxide, C6H4{O[cyclo‐P(O)OCH2CMe2CH2O]}2 or C16H24O8P2, (1), 2‐[(2′‐hydroxybiphenyl‐2‐yl)oxy]‐5,5‐dimethyl‐1,3,2‐dioxaphosphinane 2‐oxide, [cyclo‐P(O)OCH2CMe2CH2O](2,2′‐OC6H4–C6H4OH), (2), and oxybis(5,5‐dimethyl‐1,3,2‐dioxaphosphinane) 2,2′‐dioxide, O[cyclo‐P(O)OCH2CMe2CH2O]2, (3). Compound (1) is novel, whereas the results for compounds (2) and (3) have been reported previously, but we record here our results for compound (3), which we find are more precise and accurate than those currently reported in the literature. In (1), two cyclo‐P(O)OCH2CMe2CH2O groups are linked through a catechol group. The conformations about the two catechol O atoms are quite different, viz. one C—C—O—P torsion angle is −169.11 (11)° and indicates a trans arrangement, whereas the other C—C—O—P torsion angle is 92.48 (16)°, showing a gauche conformation. Both six‐membered POCCCO rings have good chair‐shape conformations. In both the trans and gauche conformations, the catechol O atoms are in the axial sites and the short P=O bonds are equatorially bound. 相似文献
11.
Mihaela Cibian Andr Bessette Andrew O'Connor Janaina G. Ferreira Garry S. Hanan 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(2):122-127
The crystal structures of fac‐(acetonitrile‐κN)(2‐{[3,5‐bis(4‐methoxyphenyl)‐2H‐pyrrol‐2‐ylidene‐κN1]amino}‐3,5‐bis(4‐<!?tlsb=0.2pt>methoxyphenyl)‐1H‐pyrrol‐1‐ido‐κN1)tricarbonylrhenium(I)–hexane–acetonitrile (2/1/2), [Re(C36H30N3O4)(CH3CN)(CO)3]·0.5C6H14·CH3CN, (2), and fac‐(2‐{[3,5‐bis(4‐methoxyphenyl)‐2H‐pyrrol‐2‐ylidene‐κN1]amino}‐3,5‐bis(4‐methoxyphenyl)‐1H‐pyrrol‐1‐ido‐κN1)tricarbonyl(dimethyl sulfoxide‐κO)rhenium(I), [Re(C36H30N3O4)(C2H6OS)(CO)3], (3), at 150 K are reported. Both complexes display a distorted octahedral geometry, with a fac‐Re(CO)3 arrangement and one azadipyrromethene (ADPM) chelating ligand in the equatorial position. One solvent molecule completes the coordination sphere of the ReI centre in the remaining axial position. The ADPM ligand shows high flexibility upon coordination, while retaining its π‐delocalized nature. Bond length and angle analyses indicate that the differences in the geometry around the ReI centre in (2) and (3), and those found in three reported fac‐Re(CO)3–ADPM complexes, are dictated mainly by steric factors and crystal packing. Both structures display intramolecular C—H...N hydrogen bonding. Intermolecular interactions of the Csp2—H...π and Csp2—H...O(carbonyl) types link the discrete monomers into extended chains. 相似文献
12.
Liang Qiao Xiao-Gang Chen Ji-Xing Gao Yong Ai 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(6):728-733
The crystal structures of three quinuclidine‐based compounds, namely (1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine monohydrate, C7H13N3·H2O ( 1 ), 1,2‐bis(1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine, C14H22N4 ( 2 ), and 1,2‐bis(1‐azoniabicyclo[2.2.2]octan‐3‐ylidene)hydrazine dichloride, C14H24N42+·2Cl? ( 3 ), are reported. In the crystal structure of 1 , the quinuclidine‐substituted hydrazine and water molecules are linked through N—H…O and O—H…N hydrogen bonds, forming a two‐dimensional array. The compound crystallizes in the centrosymmetric space group P21/c. Compound 2 was refined in the space group Pccn and exhibits no hydrogen bonding. However, its hydrochloride form 3 crystallizes in the noncentrosymmetric space group Pc. It shows a three‐dimensional network structure via intermolecular hydrogen bonding (N—H…C and N/C—H…Cl). Compound 3 , with its acentric structure, shows strong second harmonic activity. 相似文献
13.
Daniel E. Vicentes Ricaurte Rodríguez Patricia Ochoa Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(10):1405-1416
A concise and efficient synthesis of a series of amino‐substituted benzimidazole–pyrimidine hybrids has been developed, starting from the readily available N4‐(2‐aminophenyl)‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine. In each of N5‐benzyl‐6‐methoxy‐4‐(2‐phenyl‐1H‐benzo[d]imidazol‐1‐yl)pyrimidine‐2,5‐diamine, C25H22N6O, (I), 6‐methoxy‐N5‐(4‐methoxybenzyl)‐4‐[2‐(4‐methoxyphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, C27H26N6O3, (III), 6‐methoxy‐N5‐(4‐nitrobenzyl)‐4‐[2‐(4‐nitrophenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, C25H20N8O5, (IV), the molecules are linked into three‐dimensional framework structures, using different combinations of N—H…N, N—H…O, C—H…O, C—H…N and C—H…π hydrogen bonds in each case. Oxidative cleavage of 6‐methoxy‐N5‐(4‐methylbenzyl)‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, (II), with diiodine gave 6‐methoxy‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, which crystallized as a monohydrate, C19H18N6O·H2O, (V), and reaction of (V) with trifluoroacetic acid gave two isomeric products, namely N‐{5‐amino‐6‐methoxy‐6‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidin‐2‐yl}‐2,2,2‐trifluoroacetamide, which crystallized as an ethyl acetate monosolvate, C21H17F3N6O2·C4H8O2, (VI), and N‐{2‐amino‐6‐methoxy‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidin‐5‐yl}‐2,2,2‐trifluoroacetamide, which crystallized as a methanol monosolvate, C21H17F3N6O2·CH4O, (VIIa). For each of (V), (VI) and (VIIa), the supramolecular assembly is two‐dimensional, based on different combinations of O—H…N, N—H…O, N—H…N, C—H…O and C—H…π hydrogen bonds in each case. Comparisons are made with some related structures. 相似文献
14.
Magorzata Szczesio Andrzej Olczak Katarzyna Gobis Henryk Foks Marek L. Gwka 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(3):o99-o103
Dimethyl (3,4‐dichlorobenzoyl)carbonohydrazonodithioate, C10H10Cl2N2OS2, (D1), dibenzyl (3,4‐dichlorobenzoyl)carbonohydrazonodithioate, C22H18Cl2N2OS2, (D2), dimethyl (3,4‐dichlorobenzoyl)‐1‐methylcarbonohydrazonodithioate, C11H12Cl2N2OS2, (D3), 3,4‐dichloro‐N′‐(1,3‐dithiolan‐2‐ylidene)‐N‐methylbenzohydrazide, C11H10Cl2N2OS2, (D4), were synthesized as potential tuberculostatics. Compound (D1) (with two molecules in the asymmetric unit) was the only one showing tuberculostatic activity of the same range as the common drugs isoniazid and pyrazinamide. The molecular structures of the studied compounds depend on the substitution at the N atom adjacent to the carbonyl group. In the case of the unsubstituted derivatives (D1) and (D2), their central frames are generally planar with a twist of the 3,4‐dichlorophenyl ring by 30–40°. Until now, coplanarity of the aromatic ring with the (methylene)carbonohydrazone fragment has been considered a prerequisite for tuberculostatic activity. The N‐methylated derivatives (D3) and (D4) show an additional twist along the N—C(=O) bond by 20–30° due to the spatial repulsion introduced by the methyl substituent. 相似文献
15.
Badiadka Narayana Hemmige S. Yathirajan Ravindranath S. Rathore Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(9):664-669
4‐Antipyrine [4‐amino‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one] and its derivatives exhibit a range of biological activities, including analgesic, antibacterial and anti‐inflammatory, and new examples are always of potential interest and value. 2‐(4‐Chlorophenyl)‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, C19H18ClN3O2, (I), crystallizes with Z′ = 2 in the space group P, whereas its positional isomer 2‐(2‐chlorophenyl)‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, (II), crystallizes with Z′ = 1 in the space group C2/c; the molecules of (II) are disordered over two sets of atomic sites having occupancies of 0.6020 (18) and 0.3980 (18). The two independent molecules of (I) adopt different molecular conformations, as do the two disorder components in (II), where the 2‐chlorophenyl substituents adopt different orientations. The molecules of (I) are linked by a combination of N—H…O and C—H…O hydrogen bonds to form centrosymmetric four‐molecule aggregates, while those of (II) are linked by the same types of hydrogen bonds forming sheets. The related compound N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)‐2‐(3‐methoxyphenyl)acetamide, C20H21N3O3, (III), is isomorphous with (I) but not strictly isostructural; again the two independent molecules adopt different molecular conformations, and the molecules are linked by N—H…O and C—H…O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen‐bonded R22(10) ring is the common structural motif. 相似文献
16.
Helen E. Mason Judith A. K. Howard Hazel A. Sparkes 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(9):927-931
The synthesis and structures of three isoxazole‐containing Schiff bases are reported, namely, (E)‐2‐{[(isoxazol‐3‐yl)imino]methyl}phenol, C10H8N2O2, (E)‐2‐{[(5‐methylisoxazol‐3‐yl)imino]methyl}phenol, C11H10N2O2, and (E)‐2,4‐di‐tert‐butyl‐6‐{[(isoxazol‐3‐yl)imino]methyl}phenol, C18H24N2O2. All three structures contain an intramolecular O—H…N hydrogen bond, alongside weaker intermolecular C—H…N and C—H…O contacts. The C—O(H) and imine C=N bond lengths were consistent with structures existing in the enol rather than the keto form. Despite having dihedral angles <25°, none of the compounds were observed to be strongly thermochromic, unlike their anil counterparts; however, all three compounds showed a visible colour change upon irradiation with UV light. 相似文献
17.
Adam Neuba Enver Akin Sonja Herres‐Pawlis Ulrich Flrke Gerald Henkel 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(5):m194-m197
The title compounds, namely 2,6‐bis[(1,3‐dimethylimidazolin‐2‐ylidene)amino]pyridinium perchlorate, C15H24N7+·ClO4−, (I), and bis{2,6‐bis[(1,3‐dimethylimidazolin‐2‐ylidene)amino]pyridinium} μ‐oxido‐bis[trichloridoiron(III)], (C15H24N7)2[Fe2Cl6O], (II), are structurally unusual examples of the organization of molecular units via base pairing. The cations in salts (I) and (II) are derived from the bisguanidine N2,N6‐bis(1,3‐dimethylimidazolin‐2‐ylidene)pyridine‐2,6‐diamine, which associates in centrosymmetric pairs via two N—H...N hydrogen‐bond interactions. N—H...N bridges are formed between the protonated pyridine N atom and one of the nonprotonated guanidine N atoms, with N...H distances of 2.01 (1)–2.10 (1) Å. Compound (I) contains two crystallographically independent cations and anions per asymmetric unit. One of the perchlorate anions is disordered, while the [Fe2Cl6O]2− anion lies on an inversion centre. 相似文献
18.
Mojtaba Keikha Mehrdad Pourayoubi Atekeh Tarahhomi Arie van der Lee 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(3):251-259
Phosphoric triamides have extensive applications in biochemistry and are also used as O‐donor ligands. Four new mixed‐amide phosphoric triamide structures, namely rac‐N‐tert‐butyl‐N′,N′′‐dicyclohexyl‐N′′‐methylphosphoric triamide, C17H36N3OP, (I), rac‐N,N′‐dicyclohexyl‐N′‐methyl‐N′′‐(p‐tolyl)phosphoric triamide, C20H34N3OP, (II), N,N′,N′′‐tricyclohexyl‐N′′‐methylphosphoric triamide, C19H38N3OP, (III), and 2‐[cyclohexyl(methyl)amino]‐5,5‐dimethyl‐1,3,2λ5‐diazaphosphinan‐2‐one, C12H26N3OP, (IV), have been synthesized and studied by X‐ray diffraction and spectroscopic methods. Structures (I) and (II) are the first diffraction studies of acyclic racemic mixed‐amide phosphoric triamides. The P—N bonds resulting from the different substituent –N(CH3)(C6H11), (C6H11)NH–, 4‐CH3‐C6H4NH–, (tert‐C4H9)NH– and –NHCH2C(CH3)2CH2NH– groups are compared, along with the different molecular volumes and electron‐donor strengths. In all four structures, the molecules form extended chains through N—H…O hydrogen bonds. 相似文献
19.
Muhammad Irfan Ashiq Ishtiaq Hussain Sally Dixon Mark E. Light Jeremy D. Kilburn 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(9):o455-o458
The structures of N‐benzyl‐N′‐{6‐[(4‐carboxylatobenzyl)aminocarbonyl]‐2‐pyridylmethyl}guanidinium, C23H23N5O3, (I), and N‐[2‐(benzylaminocarbonyl)ethyl]‐N′‐{6‐[(4‐carboxylatobenzyl)aminocarbonyl]‐2‐pyridylmethyl}guanidinium monohydrate, C26H28N6O4·H2O, (II), both form three‐dimensional supramolecular hydrogen‐bonded networks based on a dimeric primary synthon involving carboxylate–guanidinium linkages. The differences in the geometries and hydrogen‐bonding connectivities are driven by the additional methylpropionamide group and water of crystallization of (II). 相似文献
20.
Jamal Pratt Janna Hutchinson Cheryl L. Klein Stevens 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(12):o487-o491
The X‐ray crystal structures of solvates of sulfapyridine have been determined to be conformational polymorphs. 4‐Amino‐N‐(1,2‐dihydropyridin‐2‐ylidene)benzenesulfonamide (polymorph III), C11H11N3O2S, (1), 4‐amino‐N‐(1,2‐dihydropyridin‐2‐ylidene)benzenesulfonamide 1,3‐dioxane monosolvate, C11H11N3O2S·C4H8O2, (2), and 4‐amino‐N‐(1,2‐dihydropyridin‐2‐ylidene)benzenesulfonamide tetrahydrofuran monosolvate, C11H11N3O2S·C4H8O, (3), crystallized as the imide form, while piperidin‐1‐ium 4‐amino‐N‐(pyridin‐2‐yl)benzenesulfonamidate, C5H12N+·C11H10N3O2S−, (4), crystallized as the piperidinium salt. The tetrahydrofuran and dioxane solvent molecules in their respective structures were disordered and were refined using a disorder model. Three‐dimensional hydrogen‐bonding networks exist in all structures between at least one sulfone O atom and the aniline N atom. 相似文献