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1.
Charles R. Ojala William H. Ojala Doyle Britton Christopher J. Cramer 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):o518-o523
Three polymorphs of 4,4′‐diiodobenzalazine (systematic name: 4‐iodobenzaldehyde azine), C14H10I2N2, have crystallographically imposed inversion symmetry. 4‐Chloro‐4′‐iodobenzalazine [systematic name: 1‐(4‐chlorobenzylidene)‐2‐(4‐iodobenzylidene)diazane], C14H10ClIN2, has a partially disordered pseudocentrosymmetric packing and is not isostructural with any of the polymorphs of 4,4′‐diiodobenzalazine. All structures pack utilizing halogen–halogen interactions; some also have weak π (benzene ring) interactions. A comparison with previously published methylphenylketalazines (which differ by substitution of methyl for H at the azine C atoms) shows a fundamentally different geometry for these two classes, namely planar for the alazines and twisted for the ketalazines. Density functional theory calculations confirm that the difference is fundamental and not an artifact of packing forces. 相似文献
2.
The new compounds Pr8(C2)4Cl5 (1), Pr14(C2)7Cl9 (2), Pr22(C2)11Cl14 (3), Ce2(C2)Cl (4), La2(C2)Br (5), Ce2(C2)Br (6), Pr2(C2)Br (7), Ce18(C2)9Cl11 (8), and Ce26(C2)13Cl16 (9) were prepared by heating mixtures of LnX3, Ln and carbon or in an alternatively way LnX3, and “Ln2C3–x” in appropriate amounts for several days between 750 and 1200 °C. The crystal structures were investigated by X‐ray powder analysis (5–7) and/or single crystal diffraction (1–4, 8, 9). Pr8(C2)4Cl5 crystallizes in space group P21/c with the lattice parameters a = 7.6169(12), b = 16.689(2), c = 6.7688(2) Å, β = 103.94(1) °, Pr14(C2)7Cl9 in Pc with a = 7.6134(15), b = 29.432(6), c = 6.7705(14) Å, β = 104.00(3) °, Pr22(C2)11Cl14 in P21/c with a = 7.612(2), b = 46.127(9), c = 6.761(1) Å, β = 103.92(3) °, Ce2(C2)2Cl in C2/c with a = 14.573(3), b = 4.129(1), c = 6.696(1) Å, β = 101.37(3) °, La2(C2)2Br in C2/c with a = 15.313(5), b = 4.193(2), c = 6.842(2) Å, β = 100.53(3) °, Ce2(C2)2Br in C2/c with a = 15.120(3), b = 4.179(1), c = 6.743(2) Å, β = 101.09(3) °, Pr2(C2)2Br in C2/c with a = 15.054(5), b = 4.139(1), c = 6.713(3) Å, β = 101.08(3) °, Ce18(C2)9Cl11 in P$\bar{1}$ with a = 6.7705(14), b = 7.6573(15), c = 18.980(4) Å,α = 88.90(3) °, β = 80.32(3) °, γ = 76.09(3) °, and Ce26(C2)13Cl16 in P21/c with a = 7.6644(15), b = 54.249(11), c = 6.7956(14) Å, β = 103.98(3) ° The crystal structures are composed of Ln octahedra centered by C2 dumbbells. Such Ln6(C2)‐octahedra are condensed into chains which are joined into undulated sheets. In compounds 1–4 three and four up and down inclined ribbons alternate (4+4–, 4+3–3+4–, 4+4–3+4–4+3–), in compounds 8 and 9 four and five (4+5–, 5+4–4+5–4+4–), and in compounds 4–7 one, one ribbons (1+1–) are present. The Ln‐(C2)‐Ln layers are separated by monolayers of X atoms. 相似文献
3.
Samuel Robinson Jebas A. Sinthiya B. Ravindran Durai Nayagam Dieter Schollmeyer S. Alfred Cecil Raj 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):o361-o364
In the title compounds, 4‐aminopyridinium 4‐aminobenzoate dihydrate, C7H6NO2−·C5H7N2+·2H2O, (I), and 4‐aminopyridinium nicotinate, C5H7N2+·C6H4NO2−, (II), the aromatic N atoms of the 4‐aminopyridinium cations are protonated. In (I), the asymmetric unit is composed of two 4‐aminopyridinium cations, two 4‐aminobenzoate anions and four water molecules, and the compound crystallizes in a noncentrosymmetric space group. The two sets of independent molecules of (I) are related by a centre of symmetry which is not part of the space group. In (I), the protonated pyridinium ring H atoms are involved in bifurcated hydrogen bonding with carboxylate O atoms to form an R12(4) ring motif. The water molecules link the ions to form a two‐dimensional network along the (10) plane. In (II), an intramolecular bifurcated hydrogen bond generates an R12(4) ring motif and inter‐ion hydrogen bonding generates an R42(16) ring motif. The packing of adduct (II) is consolidated via N—H...O and N—H...N hydrogen bonds to form a two‐dimensional network along the (10) plane. 相似文献
4.
Christopher S. Frampton David D. MacNicol Derek R. Wilson 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(5):o188-o191
The title compounds, C18H21NO and C18H21NS, in their enantiomerically pure forms are isostructural with the enantiomerically pure 4‐(4‐hydroxyphenyl)‐2,2,4‐trimethylchroman and 4‐(2,4‐dihydroxyphenyl)‐2,2,4‐trimethylchroman analogues and form extended linear chains via N—H...O or N—H...S hydrogen bonding along the [100] direction. The absolute configuration for both compounds was determined by anomalous dispersion methods with reference to both the Flack parameter and, for the light‐atom compound, Bayesian statistics on Bijvoet differences. 相似文献
5.
6.
A. Abdul Ajees S. Parthasarathy S. Manikandan R. Raghunathan 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):473-475
The title compound, C23H15Cl2NO3, crystallizes with two independent molecules in the asymmetric unit. The chromanone moiety consists of a benzene ring fused with a six‐membered heterocyclic ring which adopts a sofa conformation. The five‐membered spiroisoxazoline ring is in an envelope conformation. The p‐chlorophenyl rings bridged by the five‐membered ring are nearly perpendicular to each other. The chromanone moiety of one molecule packs into the cavity formed by the p‐chlorophenyl rings of a second molecule through the formation of C—H?π interactions. The structure is stabilized by weak C—H?O, C—H?Cl and C—H?π interactions. 相似文献
7.
Manuel Rubio‐Arroyo Federico Jimnez‐Cruz Guadalupe Prez‐Caballero Simn Hernndez‐Ortega 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1028-1029
The crystal structure of the title compound, C19H16N2O2, displays a trans configuration of the azo moiety, which forms an intramolecular O—H?N=N hydrogen bond. The H?N and O?N distances are 1.81 (3) and 2.581 (4) Å, respectively. The azobenzene moiety is approximately planar, and has a dihedral angle of ca 23° with the substituted phenyl group. 相似文献
8.
Clair Bilton Judith A. K. Howard N. N. Laxmi Madhavi Gautam R. Desiraju Frank H. Allen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1356-1358
The title compounds, C8H10O2, (I), and C12H14O2, (II), occurred as by‐products in the controlled synthesis of a series of bis(gem‐alkynols), prepared as part of an extensive study of synthon formation in simple gem‐alkynol derivatives. The two 4‐(gem‐alkynol)‐1‐ones crystallize in space group P21/c, (I) with Z′ = 1 and (II) with Z′ = 2. Both structures are dominated by O—H?O=C hydrogen bonds, which form simple chains in the cyclohexane derivative, (I), and centrosymmetric dimers, of both symmetry‐independent molecules, in the cyclohexa‐2,5‐diene, (II). These strong synthons are further stabilized by C[triple‐bond]C—H?O=C, Cmethylene—H?O(H) and Cmethyl—H?O(H) interactions. The direct intermolecular interactions between donors and acceptors in the gem‐alkynol group, which characterize the bis(gem‐alkynol) analogues of (I) and (II), are not present in the ketone derivatives studied here. 相似文献
9.
《Magnetic resonance in chemistry : MRC》2002,40(11):738-742
An unsymmetrical heterocyclic diamine, 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(4‐aminophenoxy)‐4‐phenyl]‐(2H)phthalazin‐1‐one, was synthesized. Its 1H and 13C NMR spectra were completely assigned by utilizing the two‐dimensional heteronuclear 13C–1H multiple‐bond coherence (HMBC) spectroscopy, and heteronuclear 13C–1H one‐bond correlation spectroscopy, homonuclear shift correlation spectroscopy (H,H‐COSY) and rotating frame Overhauser enhancement spectroscopy (ROESY). The structure of the compound was shown to be the phthalazinone rather than the phthalazine ether from cross peaks and chemical shifts of the protons. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
10.
Hartmut Fuess Michaela Schwarz Erich F. Paulus Jens Hartung Ingrid Svoboda 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):o386-o388
The title compound, C20H18ClNOS2, is a thiazole‐derived thiohydroxamic acid O‐ester. The value of Z′ is 3 and the asymmetric unit comprises three molecules of identical helicity along the N—O bond. Two of these show an anti and the third a syn arrangement of substituents attached in positions 3 and 4 to the 1,3‐thiazole nucleus. 相似文献
11.
L. C. R. Andrade M. J. M. de Almeida J. A. Paixo F. M. Fernandes Roleira E. J. Tavares da Silva 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(6):o330-o331
The title compound, C21H28O4, has a 4‐acetoxy substituent positioned on the steroid α face. The six‐membered ring A assumes a conformation intermediate between 1α,2β‐half chair and 1α‐sofa. A long Csp3—Csp3 bond is observed in ring B and reproduced in quantum‐mechanical ab initio calculations of the isolated molecule using a molecular‐orbital Hartree–Fock method. Cohesion of the crystal can be attributed to van der Waals interactions and weak C—H...O hydrogen bonds. 相似文献
12.
Dun‐Ru Zhu Yan Xu Yong‐Jiang Liu You Song Yong Zhang Xiao‐Zeng You 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):242-243
In the title compound, 4‐(4H‐1,2,4‐triazol‐4‐yliminomethyl)phenol hemihydrate, C9H8N4O·0.5H2O or (I)·0.5H2O, molecules of (I) are arranged as layers running along the b axis through intermolecular O—H?N and C—H?O hydrogen bonds. These layers are stabilized by hydrogen‐bonded water molecules to form three‐dimensional networks. 相似文献
13.
Doyle Britton 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o35-o37
The title compound, C13H9NO, crystallizes with four molecules in the asymmetric unit. Each of the four crystallographically independent molecules forms a chain parallel to the a axis with symmetry‐equivalent molecules. These chains are held together by similar O—H·NC hydrogen bonds, with approximately linear O—H·N angles and significantly bent H·N—C angles. The four different molecules are related by strong elements of pseudosymmetry. To better describe the pseudosymmetry, the structure has been reported in the non‐standard space group . 相似文献
14.
15.
Cecilia Rodríguez de Barbarín Sylvain Berns Francisco Snchez‐Viesca Martha Berros 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(7):o360-o362
In the structure of the title compound, C10H8BrNS, the dihedral angles between the planes of the thiazole and aryl rings, viz. 4.2 (6) and 7.5 (6)° for the two independent molecules, are consistent with insignificant molecular perturbation by the weak intermolecular contacts. The molecules are close to being related by a non‐crystallographic inversion centre, with C—H⃛π and π–π intermolecular interactions observed. 相似文献
16.
Thomas Gelbrich Ann L. Bingham Terence L. Threlfall Michael B. Hursthouse 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(4):o205-o207
The δ polymorph of sulfanilamide (or 4‐aminobenzenesulfonamide), C6H8N2O2S, displays an overall three‐dimensional hydrogen‐bonded network that is dominated by a two‐dimensional substructure with R22(8) rings; these result from dimeric N—H...O interactions between adjacent sulfonamide groups. This study shows how the polymorphism of sulfanilamide is linked to its versatile hydrogen‐bonding capabilities. 相似文献
17.
Clemens Schmetterer Herta Silvia Effenberger Martin C. J. Marker Hans Flandorfer 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(3):i9-i11
Work on the ternary Ni–Sn–Zn phase diagram revealed the existence of the title compound pentanickel tetratin zinc, Ni3.17Sn2.67Zn0.67 [Schmetterer et al. (2012). Intermetallics, doi:10.1016/j.intermet.2011.05.025]. It crystallizes in the Ni5Ga3Ge2 structure type (orthorhombic, Cmcm) and is related to the InNi2 type (hexagonal, P63/mmc) of the neighbouring Ni3Sn2 high‐temperature (HT) phase, but is not a superstructure. The crystal structure was determined using single‐crystal X‐ray diffraction. Its homogeneity range was characterized using electron microprobe analysis. Phase analysis at various temperatures indicated that the phase decomposes between 1073 and 1173 K, where a more extended ternary solid solution of the Ni3Sn2 HT phase was found instead. 相似文献
18.
Wenhui Zhang Allen G. Oliver Anthony S. Serianni 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(10):o496-o498
4‐Deoxy‐4‐fluoro‐β‐d ‐glucopyranose, C6H11FO5, (I), crystallizes from water at room temperature in a slightly distorted 4C1 chair conformation. The observed chair distortion differs from that observed in β‐d ‐glucopyranose [Kouwijzer, van Eijck, Kooijman & Kroon (1995). Acta Cryst. B 51 , 209–220], (II), with the former skewed toward a BC3,O5 (boat) conformer and the latter toward an O5TBC2 (twist–boat) conformer, based on Cremer–Pople analysis. The exocyclic hydroxymethyl group conformations in (I) and (II) are similar; in both cases, the O—C—C—O torsion angle is ∼−60° (gg conformer). Intermolecular hydrogen bonding in the crystal structures of (I) and (II) is conserved in that identical patterns of donors and acceptors are observed for the exocyclic substituents and the ring O atom of each monosaccharide. Inspection of the crystal packing structures of (I) and (II) reveals an essentially identical packing configuration. 相似文献
19.
A new monomer diacid, 1,2-dihydro-2-(4-carboxylphenyl)-4-[4-(4-carboxylphenoxy)-3-methylphenyl]phtha-lazin-1-one (3), was synthesized through the aromatic nucleophilic substitution reaction of a readily available unsymmetrical phthalazinone 1 bisphenol-like with p-chlorobenzonitrile in the presence of potassium carbonate in N,N-dimethylacetamide and alkaline hydrolysis. The diacid could be directly polymerized with various aromatic diamines 4a-4e using triphenyl phosphite and pyridine as condensing agents to give five new aromatic poly(ether amide)s 5a-5e containing the kink non-coplanar heterocyclic units with inherent viscosities of 1.30-1.54 dL/g.The polymers were readily soluble in a variety of solvents such as N,N-dimethylformamide (DMF), N,N-dimethyl-acetamide (DMA), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidinone (NMP), and even in m-cresol and pyridine (Py). The transparent, flexible and tough films could be formed by solution casting. The glass transition tem-peratures Tg were in the range of 286-317℃. 相似文献
20.
Jacek Zaleski Zdzisaw Daszkiewicz Janusz B. Kyzio 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):754-757
In the title compounds, C6H8N3O2+·NO3? and C5H6N3O2+·CH3SO3?, respectively, the cations are almost planar; the twist of the nitramino group about the C—N and N—N bonds does not exceed 10°. The deviations from coplanarity are accounted for by intermolecular N—H?O interactions. The coplanarity of the NHNO2 group and the phenyl ring leads to the deformation of the nitramino group. The C—N—N angle and one C—C—N angle at the junction of the phenyl ring and the nitramino group are increased from 120° by ca 6°, whereas the other junction C—C—N angle is decreased by ca 5°. Within the nitro group, the O—N—O angle is increased by ca 5° and one O—N—N angle is decreased by ca 5°, whereas the other O—N—N angle remains almost unchanged. The cations are connected to the anions by relatively strong N—H?O hydrogen bonds [shortest H?O separations 1.77 (2)–1.81 (3) Å] and much weaker C—H?O hydrogen bonds [H?O separations 2.30 (2)–2.63 (3) Å]. 相似文献