Synthesis,Crystal Structure,and Characterization of 2-Phenyl-N-(pyrazin-2-yl)Acetamide

The title compound, 2-Phenyl-N-(pyrazin-2-yl)acetamide, C₁₂H₁₁N₃O, was prepared by the coupling reaction and the product was crystallized by using toluene and methanol mixture(1:1) The structure of the compound was confirmed by elemental analysis, FTIR, ¹H NMR, thermogravimetric analysis, differential thermal analysis, UV-Visible spectroscopy, and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P 2₁/c with the following unit-cell parameters: a = 8.1614(10), b = 14.9430(13), c = 9.3877(9) Å, β = 103.653(12)°, and Z = 4. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 0.0465 for 1486 observed reflections. An intramolecular C&sbnd;H···O hydrogen bond generates an S(6) graph-set motif. In the crystal, molecules are linked by N&sbnd;H···O and C&sbnd;H···O hydrogen bonds, forming a two-dimensional network.     

[Co(H2O)6](C18H15O4SO3)2·4H2O的合成和晶体结构

以芒柄花素为先导化合物,合成了水溶性的[Co(H2O)6](C18H15O4SO3)2·4H2O,并采用IR, 1H NMR, TG-DTA, XRD和单晶X射线衍射法对其结构进行了表征.单晶X射线衍射结果表明:[Co(H2O)6]2+、C18H15O4SO 3和H2O之间存在多种氢键,形成晶体结构中的亲水区.异黄酮骨架间反平行排列,面对面和边对面芳香堆积作用同时存在于其中,构成晶体结构中的疏水区.磺酸根是连接亲水区和疏水区的桥梁.氢键、芳香堆积作用以及阴阳离子之间的静电引力共同将标题化合物组装成具有三维网络结构的超分子.     

Crystal and molecular structures of <Emphasis Type="Italic">trans</Emphasis>-2-(4′-dimethylaminobenzylideneacetyl)-5,5-dimethylcyclohexane-1,3-dione

The crystal and molecular structures of a cyclic β-triketone, namely, trans-2-(4′-dimethylaminobenzylideneacetyl)-5,5-dimethylcyclohexane-1,3-dione (I), are determined using X-ray diffraction analysis. It is established that the compound in the crystalline state exists in a diketo-enol form stabilized by intramolecular hydrogen bonds. The specific features of the structure and the physicochemical and fluorescence properties of the compound are discussed.     

Structural variation in palladium nanoparticles of the C-Pd system when dissolving hydrogen in them

The structure of nanocomposites of the C-Pd system has been studied by X-ray diffraction analysis and transmission electron microscopy. Variations in the lattice period of nanosized palladium, the average amount of hydrogen dissolved in it, and the size distribution of palladium nanoparticles have been analyzed as functions of the nanocomposite fabrication temperature. Based on the structural data, the solubility of hydrogen in nanosized palladium has been estimated.     

Synthesis and physico-chemical characterization of metal free, sodium and potassium phthalocyanine complexes

Sodium phthalocyanine (Na₂Pc), potassium phthalocyanine (K₂Pc) and hydrogen phthalocyanine (H₂Pc) are synthesized in pure state. These complexes are characterized using physico-chemical methods like electronic, IR spectral, magnetic susceptibility measurements, thermogravimetric analysis and X-ray powder diffraction studies. Kinetic and thermodynamic parameters associated with the thermal decomposition were calculated using thermogravimetric analytical data. X-ray diffraction studies revealed that these complexes are having monoclinic crystal lattice structure. Electrical conductivity studies are carried out using two-probe technique in the temperature range 298-473 K for each complex. Sodium phthalocyanine showed semiconducting behavior, whereas potassium phthalocyanine showed first metallic behavior in the temperature range 300-378 K and then semiconducting property in the temperature range 383-473 K. But hydrogen phthalocyanine showed semiconducting behavior in the temperature range 300-390 K and metallic conduction behavior in the temperature range 395-473 K.     

基于有机羧酸配体的Co(Ⅲ)/Cu(Ⅱ)配合物的合成、结构及表征

在溶剂热条件下,以含卤素有机羧酸3-溴-吡啶-2,6-二甲酸(H₂L)为配体,以硝酸钴、硝酸铜为金属源,合成了两例配合物:[Co(L′)₃](1)和[Cu(L′)₂]_n(2)(HL′=5-溴-吡啶-2-甲酸),通过元素分析(EA)、X射线单晶衍射(SXRD)、X射线粉末衍射(PXRD)、红外光谱(IR)和热重分析(TGA)进行结构表征。X射线单晶衍射结果表明,配体H₂L在反应过程中发生脱羧现象,生成单羧酸配体5-溴-吡啶-2-甲酸。在配合物1中,每个Co(Ⅲ)都位于略微扭曲的八面体几何构型中,不对称单元中含有两个单核单元,单核单元通过C—H…O氢键形成三维超分子结构。配合物2的不对称单元中含有一个Cu(Ⅱ),两个脱质子的L′^-配体,每个Cu(Ⅱ)都是六配位的,位于扭曲的八面体几何构型中。Cu(Ⅱ)由配体连接生成1D链结构,通过C—H…O氢键形成三维超分子结构。此外,研究了两例配合物的热稳定性能。     

The Neutron Structure of the Formyl Peptide Receptor Antagonist Cyclosporin H (CsH) Unambiguously Determines the Solvent and Hydrogen-Bonding Structure for Crystal Form II

Abstract  

Single-crystal neutron diffraction data were collected at 20 K to a resolution of 1.05 ? on a crystal of the inverse formyl peptide receptor agonist cyclosporin H, CsH, (crystal form II, CsH-II) on the Laue diffractometer VIVALDI at the Institut Laue-Langevin (Grenoble). The solvent structure and hydrogen bonding network of CsH-II have been unambiguously determined by single-crystal neutron diffraction; the agreement factor R(F ²) is 13.5% for all 2726 reflections. All hydrogen atom positions, including methyl-group orientations, have been determined by crystallographic refinement. The neutron structure of cyclosporin provides unique and complementary insights into methyl orientation, hydrogen-bonding, and solvent interactions that are not available from X-ray analysis alone.     

Experimental and theoretical spectroscopic and structural analyses of a new chalcone single crystal derived from 4-bromo-2-thiophenecarboxaldehyde

A new chalcone compound, (E)-1-([1,1′-Biphenyl]-4-yl)-3-(4-bromothiophen-2-yl)prop-2-en-1-one (BBTP), crystallizes in the monoclinic space group P2₁/c and its structure has been characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ultraviolet and visible (UV-Vis) absorption spectroscopy. The structural and spectroscopic analyses of the chalcone were calculated using DFT/B3LYP method. Molecular structure, crystal structure arrangement, and intermolecular hydrogen bond interactions were determined by single crystal X-ray diffraction method. In the crystal packing, intermolecular C?H···O hydrogen bonds and C?H···π interaction formed infinite two-dimensional sheets, thus strengthening the crystal structure. Hirshfeld surface analysis, HOMO-LUMO, and molecular electrostatic potential results are also reported.     

Synthesis,Characterization and Crystal Structure of Ethyl 2-amino-4-(4-fluorophenyl)-6-phenylcyclohexa-1,3-diene-1-carboxylate

Ethyl 2-amino-4-(4-fluorophenyl)-6-phenylcyclohexa-1,3-diene-1-carboxylate was synthesized from ethyl 6-(4-bromophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate and ammonium acetate in glacial acetic acid. The synthesized compound was characterized by elemental analysis, FT-IR, thermogravimetric analysis (TGA), differential thermal analysis (DTA), UV-Visible, and single-crystal X-ray diffraction. The title compound, ethyl 2-amino-4-(4-fluorophenyl)-6-phenylcyclohexa-1,3-diene-1-carboxylate, C₂₁H₂OFNO₂, crystallizes in the orthorhombic space group Pbca with the following unit-cell parameters: a = 17.417(2), b = 9.7287(9), c = 21.014(2) Å, and Z = 8. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 0.0644 for 1616 observed reflections. An intramolecular N–H…O hydrogen bond generates an S(6) graph-set motif. In the crystal, molecules are linked by N–H…O hydrogen bonds, forming a two-dimensional network.     

苯并[d]咪唑基Ni(Ⅱ)配合物的合成、晶体结构与荧光性质研究

以3-(4-羧苯基)-7-甲基-2-丙基-3H-苯并[d]咪唑-5-羧酸和六水合氯化镍为原料,采用混合溶剂加热回流方法合成出了一例具有三维超分子结构的镍配合物,并通过X射线单晶衍射、元素分析、红外光谱、紫外-可见光光谱和荧光光谱表征方法对其进行了结构解析和性质表征。X-射线单晶衍射结果表明,配合物属于三斜晶系,P1空间群;其晶胞参数为a=0.778 5(16) nm,b=1.126 6(2) nm,c=1.175 6(2) nm, α=113.63(3)°,β=93.24(3)°,γ=101.00(3)°,V=0.917 1(3) nm³。标题配合物为单核配合物,由4个配体阴离子连接中心Ni(II)离子形成了一维环形链,并进一步通过氢键和π-π堆积作用形成了三维超分子结构。荧光光谱分析结果表明配体和标题配合物均具有良好的荧光性质,且配合物的荧光性质优于配体。     

Structure and disorder in schultenite,lead hydrogen arsenate

The structure of lead hydrogen arsenate has been studied by pulsed neutron single crystal diffraction. The structural parameters obtained agree well with the best available X-ray data. In addition, the hydrogen atom positions and disorder have been well characterized, yielding potentially important information regarding hydrogen atom potentials.     

4-Hydroxy-N′-[(1E)-1-(4-methylphenyl)ethylidene]benzohydrazide: Synthesis, crystal structure, and spectroscopic studies

The titled compound has been synthesized by reaction of 4′-methylacetophenon with 4-hydrox-ybenzohydrazide in presence of catalytic amount of glacial acetic acid. The compound is characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR and UV-visible spectra. The crystal structure was determined by X-ray diffraction method. Both X-ray data and NMR spectra indicate that the molecule exists in a trans configuration with respect to the C=N bond. The observation of strong ν(C=O) peak in IR spectra of the aroylhydrazone compound suggests that it is in keto form in solid state. X-ray diffraction results confirm this suggestion. In the crystal structure, there are N-H...O and O-H...O hydrogen bonds and weak C-H...π interaction.     

Refinement of the crystal and molecular structure of tetraacetylethane by neutron diffraction

The structure of tetraacetylethane has been determined by neutron diffraction. The compound exists in the dienolic form, the enolic hydrogen being intramolecularly bonded to a neighbouring oxygen in a clearly asymmetric mode. The acetylacetonate residues are essentially planar.     

3-叔丁基-1-(3-羟基苯基)脲的晶体结构及密度泛函理论研究

脲类及其衍生物在化学、农业、医学等多个领域有重要用途。而芳基脲类化合物是一类重要的医药化工中间体,本文经酰化和氧化两步反应制备3-叔丁基-1-(3-羟基苯基)脲,并于室温下经溶剂挥发法获得其单晶体,对晶体的堆积及分子间作用模式进行了分析。其结构经核磁共振氢谱(¹H NMR)、红外光谱(FT-IR)、核磁共振碳谱(¹³C NMR)、质谱MS和X射线单晶衍射等方法确证,在B3LYP/6-311+G(2d, p)模式下使用密度泛函理论(DFT)进行了最优结构以及前沿轨道能量计算,对比了晶体与理论计算的分子结构。结果表明,经DFT优化的分子结构与X-射线单晶衍射确定的晶体结构基本一致,该化合物为单斜方P2₁/n空间群,晶胞参数为a=1.181 42(6) nm,b=1.762 00(8) nm,c=1.179 02(5) nm,Z=8。     

Synthesis and thermal characterization of methylammonium tetrachloro zincate (II) monohydrate crystals

Single crystals of methylammonium tetrachloro zincate (II) monohydrate were grown by slow evaporation of saturated aqueous solutions at room temperature. The grown crystals were colourless, bright and transparent. The crystals were characterized through elemental analysis, powder X‐ray diffraction, thermogravimetric (TG‐DTA) and low temperature differential scanning calorimetric (DSC) techniques. While the powder XRD pattern shows the crystallinity of the compound, the elemental analysis and the TG‐DTA confirm the stoichiometry of the compound. The low temperature DSC indicates first order structural phase transition at ‐8°C during heating cycle. The FTIR and far IR spectra of the compound show characteristic vibrational frequencies due to CH₃NH₃ and ZnCl₄^2‐ ions and other chemical bonds. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A study on hydrogen-induced amorphization in the La---Ni system

In order to investigate the mechanism of hydrogen-induced amorphization, the structure changes by hydrogen absorption in La₂Ni₇, LaNi₂, LaNi_1.5 and LaNi compounds are investigated by X-ray diffraction. Also thermal stabilities of the hydrogenated samples are examined by DSC and hydrogen desorption technique. In case of La₂Ni₇ compound, the severe lattice distortion is found as hydrogen is absorbed. However, as the hydrogen absorption-desorption cycle is repeated, the amorphization takes place. LaNi₂ and LaNi_1.5 compounds show the complete absence of diffraction lines when hydrogenated at room temperature, i.e. the hydrogen-induced amorphization has occurred. The DSC curve of the hydrogen-induced amorphous alloy shows a small exothermic peak related to the precipitation of LaH₂ and LaNi₅. LaNi compound may transform into another crystalline structure by hydrogenation at room temperature, which is different from that of original LaNi compound. It is suggested that the amorphization of a compound is dependent upon the stability of the compound and the decomposition rate to LaH₂ and LaNi₅. The mechanism of the amorphization is related to the lattice distortion caused by the motion of the metal atoms so that the surroundings of the hydrogen atoms in the amorphous state resemble those of hydrogen atoms in LaH₂.     

X-ray diffraction investigation of 1-phenyl-3-isopropyl-5-(benzothiazol-2-yl)formazan

The crystal structure of 1-phenyl-3-isopropyl-5-(benzothiazol-2-yl)formazan is investigated using X-ray diffraction. The compound crystallizes in the form of two crystallographically independent molecules (A and B) in identical conformations that are stabilized by intermolecular hydrogen bonds. The intermolecular hydrogen bonds N-H…N (N…N, 2.892 and 2.939 Å) link molecules into AB dimers. Both molecules have a flattened structure, except for the isopropyl fragment. The bonds in the formazan chains are delocalized. Molecules A and B have close geometric characteristics.     

Aluminum fluoride nanohydrate

The structure of AlF₃ · 9H₂O was established by the methods of X-ray diffraction analysis. The structure consists of isolated complex AlF₃(H₂O)₃ molecules and molecules of crystal water linked via a network of Al-F?HOH and Al-OH₂?OH₂ hydrogen bonds.     

Neutron diffraction investigation of the hydrogen positions in the crystal structure of monetite,CaHPO4

An occupation-factor analysis using single-crystal neutron diffraction data has shown that the hydrogen atoms in the structure of the mineral monetite, CaHPO₄, occupy hydrogen-bonding sites closely similar to those predicted in a previous X-ray refinement. Least-squares refinement in space groupP¯1 of the potential coordinates and isotropic temperature parameters for the three distinct proton sites led to a resultantR of 0·10 over the 371 independent neutron structure factors. Detailed analysis showed that the distribution of the hydrogen atoms was almost certainly ordered in symmetryP1 with only half of the O(6) atoms (in space groupP¯1) carrying hydrogen atoms; the short O(7)-P(1)... O(7) hydrogen bond of 2·44 Å across what would be a symmetry centre inP¯1 is probably unsymmetrical. Minute piezo- and pyroelectric effects confirmedP1 as the space group. Further refinement of the X-ray data in space groupP1 indicated that the deviations from centrosymmetry must be small and, so far as can be detected, confined to the hydrogen atoms.We thank Mr James R. Lehr for the crystal, Prof. W. G. Perdok for the piezoelectric measurement, and Dr. G. Ferraris for a useful discussion. We are also grateful to Mr. D. H. C. Harris and the staff of the University Support Group for help at AERE, and to the S.R.C. for providing access to neutron and computational facilities and for financial support to WAD.     

萘羧酸膦酸铜配合物的合成与表征

本文以萘羧酸膦酸配体(5-pncH₃=(5-phosphono-1-naphthalenecarboxylic acid)和高氯酸铜为原料,在水热条件下自组装得到了一维配合物Cu_0.5(5-pncH₂)(H₂O)_1.5(1)。采用单晶衍射(X-Ray)、元素分析(EA)、红外光谱(FT-IR)、粉末衍射(Powder X-Ray)、热重分析(TG-DTG)对配合物进行晶体结构和热稳定性表征。晶体结构分析表明:该配合物结晶于正交晶系,Pbcm空间群,a=0.667 88(2) nm,b=0.884 14(2) nm,c=4.174 03(9) nm。配合物1的晶体结构中相邻的金属Cu^II离子由配位水分子连接成一维锯齿状无机链。这些相邻的无机链通过萘羧酸膦酸配体上未配位的双重羧基氢键连接成层状结构。热稳定性研究表明,配合物呈现出逐级分解过程,在350 ℃以下能够保持配合物骨架结构的稳定性。