共查询到20条相似文献,搜索用时 15 毫秒
1.
Heather J. Buchanan Philip J. Cox James L. Wardell 《Journal of chemical crystallography》1996,26(3):219-222
3-Triphenylstannylcholest-5-ene (1) has been synthesised and its molecular structure has been determined by single crystal X-ray diffraction. Refinement in the triclinic space groupP1 witha=7.805(6),b=7.862(5),c=32.351(10)Å, =90.87(8), =94.77(8) and =101.15(4)o converged atR=0.063. One of the two crystallographically independent molecules in the unit cell has a patially disordered side chain. The bond lengths and valency angles about tin indicate some steric hindrance due to the proximity of one of the phenyl rings with the B ring of the steroid nucleus. 相似文献
2.
Two crystalline adducts have been isolated from the reaction of triethylenediamine with aqueous hydrogen peroxide and characterized by X-ray crystallography. ComplexI, ON(CH2CH2)3NO·3H2O2, crystallizes in space groupP41212 witha=6.772(1),c=23.664(3) Å, andZ=4. The triethylenediamineN,N-dioxide molecule occupies a site of symmetry 2, as does one of the two independent hydrogen peroxide molecules which exhibits orientational disorder. In the crystal structure, both molecular components are linked by hydrogen bonds to form a three-dimensional network. Crystals of compoundII, ON(CH2CH2)3NO·3H2O2, belong to space groupPca21, witha=15.397(1),b=7.126(2),c=9.030(4) Å, andZ=4. TheN,N-dioxide and water molecules form hydrogen-bonded corrugated layers spaced between the (200) family of planes. The structures have been refined toR
F values of 0.065 (I) and 0.049 (II) using, respectively, 1171 and 747 observed MoK data. 相似文献
3.
The crystal structures of four liquid-crystal (LC) compounds belonging to 4-acylphenyl 4′-alkyloxybenzoates with the general formula C n H2n + 1-C(O)-C6H4-O-C(O)-C6H4-O-C m H2m + 1 numbered as 1/6, 1/7,2/7, and 3/7 (the numbers in the code indicate the ratios of the numbers of alkyl-chain units, n/m) are determined. Compounds 1/6 and 1/7 form smectic and nematic phases, but they are monotropic mesogens, whereas compounds 2/7 and 3/7 form only an enantiotropic smectic phase. Compound 3/7 crystallizes in two crystal modifications—triclinic with Z′ = 2 (3/7 tr ) and monoclinic with Z′ = 4 (sp. gr. P2, 3/7 mon ). All crystals consist of alternating aromatic and aliphatic regions and are characterized by the presence of weak directional interactions, such as C-H...O hydrogen bonds and π-stacking interactions. This provides the necessary conditions for the formation of a mesophase, and the existence of two types of structure-forming units is in line with the formation of a smectic phase. An explanation is proposed for the monotropic properties of 1/6 and 1/7. 相似文献
4.
Maurizio Remelli Fernando Pulidori Remo Guerrini Valerio Bertolasi 《Journal of chemical crystallography》1997,27(9):507-513
The natural amino acid L-Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid) has been synthesized following a new pathway which gives a chemically and optically pure product with an excellent yield. The crystal structures of a synthetic intermediate, Nπ-hydroxymethyl-spinacine, and a spinacine derivative, Nα-methyl-spinaceamine, have been investigated through X-ray diffraction: Spi(πMeOH)·H2O, monoclinicP2 i,a=8.571(1),b=6.682(1),c=8.588(1) Å, and β=94.67(1)o. Spm(αMe)·2HCl·H2O, triclinicP l,a=7.492(4),b=10.799(3),c=7.040(2) Å, α=91.88(2), β=98.36(3) and γ=73.34(3)o. Spi(πMeOH) crystallizes with a water molecule and displays a zwitterionic character. The carboxylate group is in equatorial position and forms a short electrostatic interaction of 2.618(2) Å between one of its oxygens and the protonated nitrogen of the tetrahydropyridine ring. The crystal packing is assured by strong O?H???O, O?H???N, N?H???N intermolecular hydrogen bonds and C?H???O close contacts. The biprotonated compounds Spm(αMe) crystallizes with two Cl? anions and a water molecule. The positive charge on the imidazole ring is delocalized on the conjugated moiety N=C?N. The crystal is built up by clusters formed by two biprotonated Spm(αMe) molecules, four Cl? anions and two water molecules linked together by hydrogen bonds. 相似文献
5.
The crystal structure of the title compound (C27H44NO2Cl) is determined by X-ray structure analysis. The compound crystallizes in the orthorhombic space group P212121 with the unit cell parameters a = 7.207(1) Å, b = 11.292(1) Å, and c = 32.373(5) Å. The structure is solved by direct methods and refined to R = 0.060. Rings A and C exist in the chair conformation. Ring B adopts a half-chair conformation, and ring D is a 13β envelope. The A/B ring junction is quasi-trans, while the B/C and C/D ring systems are trans fused about the C(8)–C(9) and C(13)–C(14) bonds, respectively. Molecules are linked together by the C-H?O hydrogen bonds. 相似文献
6.
Derek H. R. Barton Bin Hu Joseph H. Reibenspies 《Journal of chemical crystallography》1998,28(3):239-241
Ergosterol acetate, in pyridine, reacts with hydrogen peroxide and catalytic amounts of FeCl3 to afford the unusual product 5,9-peroxyergosta-7,22-dien-6-one-3-ol acetate. The peroxide, in the title structure, is seen to bridge the C5 and C9 positions of the sterol backbone. Crystal data: C30H44O5, orthorhombic, P212121, a = 6.552(2), b = 11.048(8), c = 37.60(2), V = 2772(3)Å3, Z = 4. 相似文献
7.
8.
Arnold L. Rheingold Cynthia J. Baldacchini Christopher W. Grote 《Journal of chemical crystallography》1989,19(1):25-37
The crystal and molecular structures of three 2,4,6-trinitrobenzene derivatives have been determined. Forα,α,α-trifluoro-2,4,6-trinitrotoluene (1): monoclinic,P21/n,a=7.510(2),b=9.273(2),c=14.984(0) Å,β=99.02(2)°,V=1028.1(4)° Å3,Z=4,D=1.816 g cm?3,R(F)=0.051, andR(wF)=0.055. For 2,4,6-trinitrobenzamide (2): orthorhombic,Pbca,a=9.248(3),b=14.377(6),c=17.729(4) Å,V=1958(1) Å3,Z=8,D=1.737 g cm?3,R(F)=0.073, andR(wF)=0.077. For 2,4,6-trinitrobenzoic acid (3): orthorhombic,P212121,a=6.553(1),b=11.405(2),c=12.796(2) Å,V=956.3(3) Å3,Z=4,D=1.785 g cm?3,R(F)=0.045, andR(wF)=0.046.1 crystallizes as discrete molecules,2 as weakly hydrogen-bonded dimers and3 as a chiral polymer of hydrogen-bonded helices. In1, the presence of the nonplanar CF3 substituent causes a large twisting of theα-nitro groups out of the plane of the benzene ring, whereas the nearly planar C(O)NH2 and C(O)OH substituents in2 and3 are perpendicular to the benzene plane and do not cause a significant rotation of theα-nitro groups. 相似文献
9.
M. Sakhawat Hussain Mazhar-ul-Haque Sk. A. Ali 《Journal of chemical crystallography》1999,29(1):33-38
The title compound crystallizes in the monoclinic space group P21/n, with a = 6.225(1), b = 14.612 (1), c = 15.520 (1) Å, = 96.6(3)°, Z = 4 and V = 1402.4Å3. The stereochemistry of the 7/5-fused ring system is trans, the 7-membered and the 5-membered rings are found to be in the chair and envelope conformations, respectively. This represents the first study of a compound containing the 7/5-ring skeleton shown in (3) below. 相似文献
10.
Abstract The title compound 3-quinuclidinyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate was obtained by the reaction of methyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate with 3-quinuclidinol in n-heptane. Its structure was characterized by 1H, 13C NMR, MS and X-ray single-crystal diffraction techniques: C20H25NO3, M
r = 327.41, orthorhombic, space group P212121 with a = 8.547(2), b = 11.428(4), c = 18.288(5) ?, V = 1786.3(9) ?3, Z = 4. The title compound comprises a tertiary α-hydroxy acid and a bicyclo[2.2.2]octan moiety. The crystal structure shows the presence of the intermolecular O(1)–H(1)···N(1)
hydrogen bonds.
Index Abstract The title compound, 3-quinuclidinyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate was obtained by the reaction of methyl
α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate with 3-quinuclidinol in n-heptane and its crystal structure determined. The
title compound comprises a tertiary α-hydroxy acid and a bicyclo[2.2.2]octan moiety. The crystal structure shows the presence
of the intermolecular O(1)–H(1)···N(1) hydrogen bonds.
相似文献
11.
A. Kolocouris N. Kolocouris G. B. Foscolos G. Fytas A. Hempel N. Camerman A. Camerman S. J. Hamodrakas 《Journal of chemical crystallography》1993,23(8):663-667
A tricyclic -lactam ketone, 1,10a-Dihydropyrrolo[1,2]isoquinoline-3,10(2H,5H)-dione, and its corresponding Mannich base, 10a-(Dimethylaminomethyl)-1,10a-dihydropyrrolo[1,2b]isoquinoline-3,10(2H,5H)-dione hydrochloride, have been synthesized. The molecular and crystal structures of both compounds were studied by NMR-spectroscopy and X-ray crystallography. Unit cell parameters are:a=8.799(7),b=7.137(6),c=16.156(8)Å,=76.28(5)°, space groupP21/c forthe first compound, anda=15.343(9),b=7.490(6),c=13.465(8) Å,=110.98(3)°, space groupP21/c for the second. The structures were refined to discrepancy factorsR=0.068 for 1261 andR=0.047 for 2138 observed CuK
data, respectively. The conversion of the tricyclic -lactam ketone to its corresponding Mannich base does not affect thecis configuration between the fused tetrahydropyridine and -lactam rings, but does result in conformational changes in both rings. 相似文献
12.
Janina Karolak-Wojciechowska Witold Kwiatkowski Stanislaw Wojciech Markowicz 《Journal of chemical crystallography》1989,19(5):893-903
Several optically pure representatives of 2-hydroxy-3-[N-alkyl (aryl)] pinanoamines, potential chiral auxiliaries in organic synthesis, were obtained. In addition, a structural examination of 2-hydroxy-3-(N-n-butyl)-pinanoamine hydrochloride was conducted. Results of these studies confirm the structure of the amines obtained and the correctness of the proposed reaction pathway.Crystal data: C12H28NOCl,P21/c,a=13.196(1),b=8.562(1),c=14.276(1) Å,=110.41(3)°,R=0.034 for 2046 reflections.Part I,J. Cryst. Spec. Res. (1989)19, 535. 相似文献
13.
Nina Lah Ivan Leban Alenka Majcen Le Maréchal Vesna Ferk Philippe Le Grel Joachim Sieler 《Journal of chemical crystallography》2000,30(2):109-113
Two compounds have been prepared during the investigation of the reactivity of -halopyruvamides. The reaction products: 3-(4-chlorophenyl)imidazo[1,2-a]pyridine-2-carboxamide (1) and 7-carbamoyl-5-phenyl-2,3-dihydro[1,3]thiazolo[4,3-b][1,3]thiazol-4-ium chloride (2) were structurally characterized by x-ray crystallography. Compound 1 crystallizes in the orthorhombic space group Pca21 with a = 28.813(2), b = 9.369(1), and c = 9.361(1) Å. The structure contains two crystallographically different molecules. Compound 2 crystallizes in the monoclinic space group P21/c with the following cell parameters: a = 8.5895(8), b = 22.499(2), c = 7.4133(6) Å, and = 110.204(1)°. 相似文献
14.
Philip J. Cox David G. Durham Xiaojun Liu R. Michael E. Richards 《Journal of chemical crystallography》1993,23(10):779-783
A triterpenoid glycoside has been isolated from the roots of a herb used in traditional Chinese medicine. The molecular structure of this compound and its derivatives have been determined by spectroscopic studies and an X-ray analysis of the 2,3,23-triacetoxy-28-methyl ester of the aglycone. This aglycone belongs to the ursene structure series. The hydroxy group on ring E of these triterpenoids is orientated and the side chains at C(2), C(3), C(4) and C(17) are .,, and orientated, respectively. The C ring, which has a double bond at C(12)=C(13), adopts a sofa conformation. 相似文献
15.
7-Ethoxyl-4-hydroxyisoflavone was prepared and its crystal structure was examined by X-ray diffraction. Crystallization of the title compound occurs in the monoclinic, space group P2(1)/c with a = 11.144(2) Å, b = 10.209(1) Å, c = 13.191(2) Å, = 113.43(1) and Z = 4. The molecular structure of title compound consists of a benzopyranone moiety, a phenyl moiety, a hydroxyl and an ethoxyl group. The benzopyranone ring is not coplanar with the phenyl ring, the dihedral angle being 46.75. The ethoxyl group is nearly coplanar with its corresponding ring with the torsion angle 175.23(2). Three kinds of hydrogen bond and two kinds of aromatic stacking interaction link the title compounds into a three-dimensional networking structure. 相似文献
16.
The crystal structures of two samples of burbankite from the Khibiny massif, namely, low-rare-earth burbankite (Na1.82Ca1.02Y0.02)2.86(Sr2.32Ba0.43Ca0.17La0.06Ce0.02)3.00(CO3)5 from pectolite metasomatites and burbankite of the characteristic composition (Na2.22Ca0.65Y0.03)2.97 × × (Sr2.10Ba0.33Ce0.23Ca0.15La0.12Nd0.05Pr0.02)3.00(CO3)5 from alkaline hydrothermolites, were refined by the Rietveld method. The experimental data were collected on an ADP-2 diffractometer (λCuK α radiation, Ni-filter; 15.00° < 2θ < 155.00°; 2θ scan with steps 0.02°; the exposure time per step, 15–20 s; the number of (α1 + α2) reflections 556–570). All the calculations were performed using the WYRIET program (version 3.3) in the sp. gr. P63 mc. For low-rare-earth burbankite: a = 10.5263(1) Å, c = 6.5392(1) Å, R P = 3.52, R wp = 4.49, R B = 4.10, and R F = 4.11. For burbankite from alkaline hydrothermolites: a = 10.5313(1) Å, c = 6.4829(1) Å, R P = 2.54, R wp = 3.23, R B = 3.06, and R F = 3.44. The structures were refined using the anisotropic thermal parameters of cations. 相似文献
17.
The crystal structures of the anhydrous and monohydrated (dabcoH2)CuCl4nH2O salts (n = 0,1) have been determined and a comparison of their crystal structures has been reported. The anhydrous salt is monoclinic P21/c with a = 9.045(2) Å, b = 6.9270(10) Å, c = 18.767(4) Å and = 90.07(3)° with V = 1175.8(4) Å3. The hydrated salt is also monoclinic P21/c with a = 9.266(2) Å, b = 9.395(2) Å, c = 14.386(3) Å and = 93.32(3)° with V = 1250.3(5) Å3. The structures of the two salts are closely related. Both compounds contain isolated distorted (compressed) tetrahedral CuCl4
2– anions, diprotonated dabco cations, and in the case of the hydrated salt, lattice H2O molecules. In the anhydrous salt, each of the two N–H+ groups of the dabcoH2
2+ dications form bifurcated hydrogen bonds to chloride ions on adjacent CuCl4
2– anions along the c axis, thus forming chains running parallel to the c axis. In the hydrated salt, a water molecule is inserted into one of the pair of bifurcated hydrogen bonds, forming instead N–H O–H CuCl4
2– linkages. The chains thus formed are cross-linked by O–H Cl hydrogen bonds between the chains. Because of this additional hydrogen bonding, the CuCl4
2– anions in the hydrated salt are distorted further from tetrahedral geometry. 相似文献
18.
Zhao-Hui Zhou Wen-Bin Yan Hui-Lin Wan Khi-Rui Tsai Jin-Zhi Wang Sheng-Zhi Hu 《Journal of chemical crystallography》1995,25(12):807-811
Potassium and ammonium dimeric (citrato)dioxovanadium(V) hydrate K2[VO2(H2cit)]2·4H2O1 and (NH4)2[VO2(H2cit)]2·2H2O2 (H4cit=citric acid) have been prepared and characterized by X-ray structure analyses. Vanadate1 crystallizes in the monoclinic space groupP21/n (No. 14) with unit cell parameters:a=9.304(2),b=11.756(2),c=11.911(2)Å, =111.72(3)°, andD
c=1.911 g/cm3,Z=2; Vanadate2 also crystallizes in the monoclinic space groupP21/n with unit cell parameters:a=9.719(2),b=11.111(3),c=11.294(2)Å, =109.03(2)°, andD
c=1.781 g/cm3,Z=2. Each dimer contains a centro-symmetric planar four-member V2O2 ring with two exocyclic citrate entities coordinated by the oxygen atoms of the hydroxy-and -carboxylate ligands, while the other two -carboxylate groups remain uncomplexed. Principal dimensions of the V–O bonds are 1.986(4)av (hydroxy) and 1.980(3)Å(-carboxyl) for vanadate1, 1.988(2)av (hydroxy) and 1.974(3)Å(-carboxyl) for vanadate2. 相似文献
19.
Zdzisław Gałdecki Andrzej Fruziński Osman Achmatowicz Barbara Szechner Ewa Gałdecka 《Journal of chemical crystallography》1996,26(11):769-775
Methyl 6-(N-benzenesulfonylamino)-N,O-isopropylidene-2,3,6,8-tetradeoxy--d-erythrooct-2-enopyranos-4-uloside, C18H23N1O6S1, (3) crystallizes in the orthorhombic space groupP212121. The unit cell parameters are:a=7.839(2),b=10.111(2),c=24.217(5) Å. The dihydropyranone ring adopts a deformed sofa conformation with the O5 atom deviating 0.586(2) Å from the least-squares plane and the -face of the carbonyl group shielded by the terminal (C8) methyl group. 1,1-O,O-Ethylidene-3,4-dideoxy-d,l-hex-3-enoz-2-ulopyranos-5-ulose, C8H10O5, (6) crystallizes in the monoclinic space groupP21/n. The unit cell parameters are:a=6.310(1),b=18.656(3),c=7.604(1) Å, =106.01(1)°. The dihydropyranone ring adopts a deformed sofa conformation with O6 atom deviating 0.482(1) Å from the leastsquares plane and the hydroxy and dioxolanyl substituents are in pseudoaxial and pseudoequatorial positions, respectively. The average planes of six-membered and five-membered rings are approximately coplanar. 相似文献
20.
Preparation and crystal structure of spiro(5,7-dimethoxy-1(1H)oxo-2-benzopyran-3(4H),1′-cyclohexane)
V. K. Gupta D. I. Brahmbhatt U. R. Pandya S. Goswami 《Journal of chemical crystallography》2005,35(4):275-279
Spiro(5,7-dimethoxy-1(1H)oxo-2-benzopyran-3(4H),1-cyclohexane) (C16H20O4) was prepared by alkylation of o-lithio 3,5-dimethoxy-N-methyl benzamide with methylene cyclohexane oxide followed by alkaline hydrolysis and its crystal structure was determined by X-ray crystallographic techniques. The compound crystallizes into monoclinic space group P21/c with unit cell parameters: a = 11.914(3) Å, b = 9.861(3) Å, c = 12.508(7) Å, = 91.34(3), Z = 4. The structure has been solved by direct methods and refined to R = 0.039 for 1870 observed reflections. The heterocyclic ring adopts distorted sofa conformation while cyclohexane ring assumes a highly symmetric
chair conformation. The dihedral angle between the mean planes of isocoumarin nucleus and cyclohexane ring is 105.51(5). Molecules are held together in the crystal by C=H ... O hydrogen bonds. 相似文献