共查询到20条相似文献,搜索用时 109 毫秒
1.
G. V. Yukhnevich 《Crystallography Reports》2010,55(3):377-380
The formula exp(−ln2((r
XH − r
0
XH)/(r
sym
XH − r
0
XH))5/3) + exp(−ln2((r
YH − r
0
YH)/(r
sym
YH − r
0
YH))5/3) = 1 is proposed, which relates the lengths of both covalent and hydrogen bonds in homo- and heterobridges. This formula
is justified by the experimental data from the CSD bank, which was obtained by neutron diffraction for 108 O-H...N hydrogen
bridges with bond angles exceeding 170°. 相似文献
2.
Resul Sevinçek Muhittin Aygün Serap Alp Canan Kazak 《Journal of chemical crystallography》2011,41(8):1140-1144
Abstract
Molecular and crystal structure of 4-[(p-N,N-dimethylamino)benzylidene]-2-phenyloxazol-5-one, C18H16N2O2, have been determined by single crystal X-ray diffraction study. The title compound is monoclinic, with a = 12.1704(23) ?, b = 3.9810(5) ?, c = 30.9603(56) ?, β = 101.176(15)°, Z = 4, D x = 1.32 g/cm3, μ(Mo Kα) = 0.087 mm−1, and space group is P121/c1. The structure was solved by direct methods and refined to a final R = 0.047 for 3166 reflections with I > 2σ(I). The crystal structure is stabilized by C–H⋯O and C–H⋯N type intra-molecular, C–H⋯O type inter-molecular interactions. To enlighten the flexibility and the geometric isomerism (E or Z) of the title compound, the selected torsion angle is varied from −180 to 180° in every 10° separately and molecular energy profile is calculated and analyzed. 相似文献3.
Fernando Rascón-Cruz Sandra González-Gallardo Miguel A. Muñoz-Hernández Rubén A. Toscano Verónica García-Montalvo 《Journal of chemical crystallography》2009,39(7):530-534
Abstract Synthesis and X-ray structural determination of three phosphorus compounds are reported. (3b) is monoclinic P2(1)/c with a = 11.852(1), b = 12.825(1), c = 12.445(1) ?, β = 103.693(1)o; (4a) and (4b) are monoclinic P2(1)/n with a = 12.1422(16), b = 9.0860(12), c = 14.845(2) ?, β = 96.498(3)o for (4a), and a = 12.2714(16), b = 9.2812(12), c = 14.800(2) ?, β = 97.176(2)o for (4b). They all exhibit distorted tetrahedral geometry about the P atom. Ph2P(X)NHC7H7 (X=S (4a) and X=Se (4b)) show typical P–S and P–Se double bond distances and P–N single bonds, while P–S bond in 1-Ad2P(S)Cl (3b) is comparable to P–S single bonded probably due to the largeness of 1-adamantyl groups.
Graphical Abstract Synthesis and X-ray structural determination of 1-Ad2P(S)Cl (3b), Ph2P(S)NHC7H7 (4a) and Ph2P(Se)NHC7H7 (4b) are reported.
相似文献
4.
Jian Li 《Journal of chemical crystallography》2010,40(5):428-431
Abstract
The compound N-(N-acetic acid-yl-phthalimide-5-yl) maleamic acid (C14H10N2O7, M r = 318) was synthesized and its structure was characterized by elemental analysis, 1H NMR and IR spectra. The single crystal of the title compound (C14H14N2O9, M r = 354.27) was cultured and its structure was determined by single crystal X-ray diffraction. The crystal belongs to monoclinic system, space group P21/c with a = 14.3859(19), b = 12.5835(18), c = 8.6934(15) ?, β = 102.824(2)°, V = 1534.5(4) ?3, Z = 4, D c = 1.534 g cm−3, μ(Mo Kα) = 0.131 mm−1, F(000) = 736. The final refinement gave R = 0.0652, wR(F 2) = 0.1239 for 2,703 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the asymmetric unit of the title compound contains one N-(N-acetic acid-yl-phthalimide-5-yl) maleamic acid molecule and two water molecules. One of the two water molecules is disordered. The phthalimide group is essentially planar. The crystal structure of the title compound is stabilized by N–H…O and O–H…O hydrogen bonds interactions. The compound N-(N-acetic acid-yl-phthalimide-5-yl) maleamic acid possesses moderate antibacterial activity. 相似文献5.
The stabilizing effect of elastic strains on the lattice period of a quinary solid solution is considered. The expression for the stabilization factor for quinary solid solutions of the AxB1?xCyDzE1?y?z type is derived. It is shown that the stabilizing influence of the substrate sharply increases in the vicinity of the region of the chemical spinodal. The stabilization factors are calculated for the GaxIn1?xPyAszSb1?y?z and A1xGayIn1?x?yPzAs1?z quinary solid solutions isoperiodic to InAs, GaSb, and GaAs. It is shown that in the region of thermodynamic instability the stabilization factor has negative values. The changes in the composition of the above elastically strained quinary solid solutions are analyzed with respect to the equilibrium composition. It is also shown that stabilization of the lattice period does not signify the stabilization of its composition. 相似文献
6.
V. V. Kuznetsov É. R. Rubtsov V. I. Ratushnyi E. A. Kognovitskaya 《Crystallography Reports》2004,49(2):193-196
The contribution of the elastic component of the excess energy of mixing is determined for A3B5 quinary solid solutions. A relationship is derived for the activities of the components in an elastically strained solid phase of the quinary solid solutions. The correctness of the possible assumptions used in the calculation of the activity coefficients of the solid phase of a quinary solution is analyzed. The contact supercooling in the vicinity of the binary substrate isoperiods is calculated for a number of A3B5 quinary systems. It is shown that the negative contact supercoolings correspond to the thermodynamic instability boundaries of the quinary solid solutions. 相似文献
7.
I. I. Parfenova 《Crystallography Reports》2004,49(2):197-201
A model that describes the bond-length distributions in quaternary A3B5 solid solutions and allows one to consider large clusters using a minimum of computational resources is suggested. The analytical expression for the radial-distribution function is obtained. The results of the modeling describe the known experimental data well. For a number of solid solutions, the deformation energy is evaluated in the approximation of the valent force field. It is shown that the main contribution to the energy comes from the bond-length dispersion. 相似文献
8.
Thapong Teerawatananond Narongsak Chaichit Nongnuj Muangsin 《Journal of chemical crystallography》2010,40(7):591-596
Abstract
A 1:1 co-crystal structure of 11-hydroxy-2,3,9-trimethoxy-6H-chromeno[3,4-b]chromen-12-one and 11-hydroxy-2,3,9-trimethoxy-chromeno[3,4-b]chromene-6,12-dione (stemonone) was crystallized from the reaction mixture of 6-deoxyclitoriacetal and methanesulfonyl chloride, and its structure was characterized by X-ray diffraction. This co-crystal crystallizes in a triclinic crystal system, space group P(−1) with unit cell parameters of a = 8.1317(3) Å, b = 9.8224(4) Å, c = 10.7268(3) Å, α = 78.116(1)°, β = 77.463(1)°, γ = 77.140(1)°, Z = 2 and V = 804.11(3) Å3. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F 2 to final values of R 1 = 0.0501 and wR 2 = 0.1520. 相似文献9.
Hande Petek Çiğdem Albayrak Nazan Ocak İskeleli Erbil Ağar İsmet Şenel 《Journal of chemical crystallography》2007,37(4):285-290
The single crystal X-ray diffraction analysis of the title compound, C14H20N2O3, reveals that the structure is adapted to its zwitterionic form and centrosymmetric dimers are formed by N+–H···O− type ionic weak hydrogen bonds in the crystal structure. The title compound crystallizes in the triclinic space group P−1 with a = 5.9255(13) ?, b = 9.853(3) ?, c = 12.248(3) ?, α = 101.793(19)°, β = 94.941(17)°, γ = 104.36(2)°, Z = 2, Dx = 1.308 g/cm3, μ (Mo-Kα) = 0.092 mm−1. The structure was solved by direct methods and refined to a final R = 0.0371 for 2183 reflections with I > 2σ (I). The crystal structure is stabilized by N+–H···O− type intra-molecular hydrogen bonds and N+–H···O− type packing interactions referred to as weak hydrogen bonds. To elucidate conformational flexibility of the title molecule,
the selected torsion angle is varied from −180° to +180° in every 10° separately and then molecular energy profile is calculated
and construed. In addition, charge-population analysis of the crystallographically observed structure confirms its zwitterionic
form. 相似文献
10.
Vanessa Renee Little Valerio Bertolasi Keith Vaughan 《Journal of chemical crystallography》2010,40(10):807-811
Abstract
The crystal structure of methyl 1,4-di[(E)-2-(p-tolyl)-1-diazenyl]piperazine (4) has been determined by single crystal X-ray diffraction analysis. The bis-triazene (4) adopts a normal chair conformation in the piperazine ring, with puckering parameters : φ2 = −29(5)°, QT = 0.534(2) ? and θ2 = 177.0(2)°. The crystal structure of 4 is compared with the structure of the triazene (2a) and the closely related bis-triazenes (3 and 5a). The piperazine ring of 2a and 4 adopt a typical chair conformation, whereas the piperazine ring of 3 adopts an unusual pseudo-boat conformation. Crystal data: 4 C18H22N6, triclinic, space group P[`1] P\overline{1} , a = 6.8925(2) ?, b = 7.8574(3) ?, c = 16.8856(8) ?, α = 103.103(2)°, β = 90.528(2)°, γ = 101.776(2)° and V = 870.44 (6) ?3, for Z = 2. 相似文献11.
Abstract
The unstable crystals of triammonium fac-trichloridotrioxidorhenate(VII) chloride have been obtained from ammonium rhenate(VII) solution in concentrated hydrochloric acid. The crystal structure consists of fac-trichloridotrioxidorhenate(VII) anions, chloride anions and ammonium cations. Each fac-trichloridotrioxidorhenate(VII) anion and each chloride anion lies in special position of 3m site symmetry (cell parameters: a = 9.026(3) Å; c = 7.690(4) Å; space group: P63 mc). The ammonium cation lies in special position of m site symmetry. The following anion geometrical parameters of the fac-trichloridotrioxidorhenate(VII) anion have been obtained: Re–O bond length of 1.720(2) Å, Re–Cl bond length of 2.5428(9) Å, the bond angles: O–Re–O of 103.5(1)° and Cl–Re–Cl of 79.8(1)°. 相似文献12.
Andrew P. Mendham John Spencer Babur Z. Chowdhry Trevor J. Dines Muhammad Mujahid Rex A. Palmer Graham J. Tizzard Simon J. Coles 《Journal of chemical crystallography》2011,41(9):1328-1334
Abstract
The cyclic di-amino acid peptide cyclo(l-homoCySH-l-homoCySH) [(3S, 6S)-3, 6-bis(2-sulfanylethyl) piperazine-2,5-dione, C8H14N2O2S2, crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 6.1509(2) ?, b = 18.0217(9) ?, c = 29.6166(14) ?, V = 3283.0(2) ?3, Z = 12 (3 molecules, A, B and C, per asymmetric unit), D c = 1.422 g cm−3 and a linear absorption coefficient of 0.464 mm−1. The crystal structure determination was carried out with MoKα X-ray data measured at 120(2) K. In the final refinement cycle the data/restraints/parameter ratios were 5595/0/385 and goodness-of-fit on F 2 = 1.084. Final R indices for [I > 2sigma(I)] were R1 = 0.0746, wR2 = 0.1356 and R indices (all data) R1 = 0.1092, wR2 = 0.1529. The largest electron density difference peak and hole were 0.526 and −0.445e ?−3. The DKP rings in all three molecules are essentially, and unusually, planar and the C=O oxygen atoms are co-planar with the ring in each case. Ring atom rms deviations, including the =O groups, are 0.0668, 0.0658 and 0.0656 ? in molecules A, B and C, respectively. Details of the molecular geometry are compared with the compound cyclo(Gly-Gly) (Degeilh R, Marsh RE Acta Cryst 12:1007, 1959) and in addition some cyclic di-amino acid peptides in which the DKP rings have more puckered boat conformations. 相似文献13.
The [WOCl3{PhNHC(O)CHC(O−)Me}] complex has been synthesized, and its crystal structure has been determined. The coordination polyhedron of the tungsten
atom is a distorted octahedron with a meridional arrangement of three chlorine atoms. Two oxygen atoms of the acetoacetanilide
bidentate chelating ligand occupy trans positions to the O(3) oxo atom and the Cl(3) atom. The crystal structures and the IR spectra of the WOCl3{PhNHC(O)CHC(Ot-)Me} and [MoO2Cl2{(o-MePh)NHC(O)CH2C(O)Me}] complexes are compared. 相似文献
14.
Abstract
The mixed ligand dithiocarbamate complex was synthesized by the reaction between the ammonium salt of the dithiocarbamate ligands with mercury salt. There are two mercury complexes in the asymmetric unit with a compositional disorder between an ethyl group and a methyl group. A distorted tetrahedral geometry is found for each mercury atom defined by four sulphur atoms derived from two asymmetrically chelating dithiocarbamate ligands. IR spectra show thioureide υ(C–N) bands at 1491 cm−1 which is higher than observed in the simple complexes of the same ligands. The effect of alkyl substituents were observed in the magnetic unequivalence of the thioureide and phenyl units in the NMR spectroscopy. The molecules are related to each other by virtue of the compositional disorder which exists at three positions in the alkyl group across the unit. The compound crystallizes in the triclinic space group P-1 with a = 10.4764(10) ?, b = 11.0433(10) ?, c = 18.5566(17) ?, α = 97.8980(10)°, β = 95.3340(10)°, γ = 110.3010(10)°, and Z = 2. 相似文献15.
Gerard A. van Albada Maarten G. van der Horst Ilpo Mutikainen Urho Turpeinen Jan Reedijk 《Journal of chemical crystallography》2008,38(6):413-417
Abstract The compound [Cu(ampym)(μ1,1-N3)2]n (ampym = 2-aminopyrimidine) has been synthesized and characterized by X-ray crystallography and infrared spectroscopy. In
addition, Ligand Field and powder EPR measurements have been performed. The structure is solved in space group P21/c with
a = 7.303(2), b = 19.716(4), c = 5.949(1) ?, β = 98.17(3), V = 847.9(3) ?3, Z = 2 with final R = 0.0382. The coordination geometry around the Cu(II) ion is distorted square pyramidal, with four nitrogen
atoms of four bridging azido anions in the basal plane with Cu–N distances that range from 1.998(3) to 2.069(3) ?. The apical
position is occupied by a nitrogen atom of the ampym molecule at a Cu–N distance of 2.169(3) ?. The trans-basal angles are
165.7(1) and 143.9(1)°. Weak hydrogen bonding is observed between the two amine hydrogen atoms and nitrogen of an azide anion
and the pyrimidine-ring nitrogen atom of a neighbouring molecule (N···N distances 3.174(5), 3.106(4) ?). These last hydrogen
bonds (N7···N3) are forming so-called “Watson-Crick type” hydrogen bonds. In the infrared the vibrations of the coordinated
azide anion are observed at 2,062, 1,273 and 655 cm−1, while the Cu–N vibrations are observed at 370 and 224 cm−1. Ligand-field and EPR spectra are uneventful and give spectral parameters expected in the range for such Cu(II) compounds.
Magnetic susceptibility measurements reveal a weak antiferromagnetic interaction between the Cu(II) ions.
Index Abstract A new Cu(II) compound, [Cu(2-aminopyrimidine)(μ1,1-N3)2]n has been synthesized and characterized by X-ray crystallography and by IR, Ligand Field, EPR spectroscopy and magnetic susceptibility.
The coordination geometry around the Cu(II) ion is distorted square pyramidal, with four nitrogen atoms of four bridging azido
ligands in the basal plane with Cu–N distances that range from 1.998(3) to 2.069(3) ?. The apical position is occupied by
a nitrogen atom of the ampym molecule at a Cu–N distance of 2.169(3) ?. Also a very interesting hydrogen bond system occurs
between pairs of ligands in the lattice.
. 相似文献
16.
Waseeq Ahmad Siddiqui Saeed Ahmad Hamid Latif Siddiqui Tanvir Hussain Masood Parvez 《Journal of chemical crystallography》2010,40(2):116-121
Abstract
o-[(Phenyl/p-methoxyphenyl)carbamoyl]benzene sulfonamides were synthesized in a straightforward manner utilizing directly saccharin and aniline/p-anisidine as starting material and their crystal structures have been determined. (C13H12N2O3S): Mr = 276.31, monoclinic, P21/c, a = 10.277(6), b = 7.501(2), c = 16.261(10) ?, β = 96.37(2)°, V = 1,245.8(11) ?3, Z = 4. (C14 H14 N2 O4 S): Mr = 306.33, monoclinic, P21/c, a = 10.381(5), b = 7.861(2), c = 16.837(9) ?, β = 93.43(2)°, V = 1,371.5(10) ?3, Z = 4. In both structures the phenyl rings are inclined at 47.09(7) and 39.88(5)° with respect to each other and the structures are characterized by extensive inter and intramolecular hydrogen bonds. 相似文献17.
Abstract
In order to investigate the intramolecular [4 + 2] cycloaddition, we prepared some new tertiary N-(5-substituted-2-furfuryl)-N-prop-2-ynyl-p-toluidines [Hergold-Brundić et al., Acta Cryst C56:e520, 2000; Mance and Jakopčić, Mol Divers 9:229, 2005; Mance, “unpublished results”] by the alkylation of secondary N-(5-substituted-2-furfuryl)-p-toluidines with the propargyl-bromide [Mance and Šindler-Kulyk, Synth Commun 26:923, 1996]. In the course of preparation of N-(5-methoxy-2-furfuryl)-N-prop-2-ynyl-p-toluidine [Mance, “unpublished results”], besides the main product (compound 1) (Scheme 1) we obtained N,N-di(prop-2-ynyl)-p-toluidine (compound 2) as the colourless crystals. The title compound 2, N,N-di(prop-2-ynyl)-p-toluidine, C13H13N, crystallizes in monoclinic C 2/c space group with unit cell parameters: a = 19.5319(9) ?, b = 7.5230(3) ?, c = 15.9000(7) ?, β = 112.554(5)°, V = 2157.64(18) ?3, Z = 8. The crystal structure is dominated by van der Waals forces only. The bond distances around amine N atom correspond to σ dominated bonds (1.467(2), 1.462(2) and 1.419(2) ?). The angles sum around amine N atom is in accord with sp3 hybridization (343°). 相似文献18.
The crystal structure of 6,13-bis-(N,N-dimethylcarbamoyl)thioquinanthrene 3 has been determined as monoclinic, with space group P2(1)/c with lattice parameters a = 10.044(2) Å, b = 21.385(4) Å, c = 10.889(3) Å, = 102.92(3)°, Z = 4 and Dcalc = 1.342 Mg/m3. The middle 1,4-dithiin ring in the title compound 3, C24H20N4O2S2 is in a boat conformation with the dihedral angle between the planes of the aromatic rings 132.45(8)°. 相似文献
19.
Zi-Ping Cao Hong-Ru Dong Guo-Liang Shen Heng-Shan Dong 《Journal of chemical crystallography》2010,40(12):1078-1081
Abstract
(5-Methyl-3-phenyl-1H-pyrazol-1-yl)-[5-(p-tolylamino)-2H-1,2,3-triazol-4-yl]methanone was synthesized and characterized by 1H NMR, MS and IR spectra data. The structure of title compound was identified by X-ray diffraction. Compound, C20H18N6O, Mr = 358.40, crystallizes in the triclinic space group P-1 with unit cell parameters a = 10.303(6), b = 12.489(7), c = 15.305(9) ?, α = 108.489(12), β = 101.920(11), γ = 96.971(13)°, V = 1790.0(17) ?3, Z = 4, Dx = 1.330 mg/cm3. The final R was 0.0520. 相似文献20.
Rui Yuan Wei Lin Wei Yin Rong-cheng Bo Jing-jing Shi Xiao-fei Zhang Xiao-xiao Zhang Chao Wang Yu Wan Hui Wu 《Journal of chemical crystallography》2010,40(9):799-801