The molecular structure of dibutylbis(2-pyridinethiolato-5-ethyl ester)tin(IV), [SnBu2(TNEE)2]

The crystal structure of [SnBu₂(TNEE)₂], (HTNEE=5-ethyl ester of 2-mercaptopyridine-5-carboxylic acid) has been determined by X-ray single crystal diffraction study. The crystal is triclinic, space groupP,a=10.042(1),b=18.421(2),c=7.979(1) Å, =98.7(1), =107.3(1), =87.7(1)^o,V=1393(1) ų, and Z=2 The tin center is coordinated to two butyl groups and to the nitrogen and the sulfur atoms of two ligand molecules in a very distorted trapezoidal bipyramid.     

Crystal and molecular structure of Rebek's imide

The crystal and molecular structure of Rebek's imide 1 is reported. Crystal data for 1: triclinic, space group , a = 7.8733(7) Å, b = 12.712(1) Å, c = 12.789(1) Å, = 86.628(5)°, = 84.628(5)°, = 72.981(5)°, V = 1217.9(2) ų, and D _c = 1.305 g/cm³ for Z = 2 and R = 0.047. The molecule crystallizes as a cyclic, hydrogen-bonded dimer held together by two N H...O and two O H...O hydrogen bonds involving amide...carboxylic acid interactions. The dimer organizes in the solid state to form 1D ribbons.     

Persistence of layer motifs in the crystal structures of [1,4-bis-(2-methoxy-2-carbonylethyl)piperazinium (2’)] chloride and [1,4-bis-(2-amidoethyl)piperazinium (2’)] perchlorate

Two structures of the closely related piperazinium salts, [1,4-bis-(2-methoxy-2-carbonylethyl)piperazinium (2+)] chloride (1) and [1,4-bis-(2-amidoethyl)piperazinium (2+)] perchlorate (2) reveal the persistence of a layer structure, interspersed with anions, held in place by N–H···Cl, C–H···O and C–H···Cl interactions in the case of 1, and N–H···O and C–H···O interactions in the case of 2. Compound 1 crystallizes in the triclinic space group P-1 with a=6.7667(6) ?, b = 6.9467(6) ?, c=9.3880(18) ?, α=105.845(9)°, β=99.896(16)°, γ=103.600(9)°, and Z=1. Compound 2 crystallizes in the monoclinic space group P2₁/c with a = 9.0930(8) ?, b=10.0525(11) ? c=10.2104(13) ?, β=114.279(9)°, and Z=2.     

Construction of Three Novel Coordination Complexes by 3-Nitrophthalic Acid Plus N-Donor Ligands: Synthesis,Structure, and Properties

In order to explore new coordination frameworks with novel designed 3-nitrophthalic acid and N–donor ancillary ligands, three novel coordination complexes, namely, [Co₂(3-NPA)₂(2,2′-bipy)₂(H₂O)₂]?2H₂O (1), [Mn₂(3-NPA)₂(4,4′-bipy)₃(H₂O)₆]?(4,4′-bipy) (2), and [Pb₂O(3-NPA)]_n (3) (where 3-NPAH₂ = 3-nitrophthalic acid, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine), have been hydrothermally synthesized. X-ray structure analysis reveals that 1 and 2 are dinuclear structures, while 3 is a two-dimensional (2D) network polymer. And the hydrogen bonds and π–π stacking also play important roles in affecting the final structure where complexes 1-2 have 3D and 2D supramolecular architectures, respectively. These complexes have been characterized by powder X-ray diffractions (PXRD) and thermal gravimetric analyses (TGA). In addition, their photochemical properties have also been investigated.     

4- and 5-nitro-2-benzoylbenzoic acid

The structures of two isomeric nitro 2-benzoylbenzoic acids have been determined. 4-Nitro-2-benzoylbenzoic acid, C₁₄H₉NO₅, monoclinic, P2₁/c, a = 9.455(5), b = 6.632(2), c = 21.333(7)Å, = 107.96(3)°, Z = 4, V = 1270.6(9)ų, 5-nitro-2-benzoylbenzoic acid, C₁₄H₉NO₅, monoclinic, P2₁/c, a = 10.201(6), b = 8.515(4), c = 14.573(7)Å, = 101.35(4)°, Z = 4, V = 1241.1(11)ų. Both carboxylic acids form the usual H-bonded dimers across crystallographic centers of inversion. The nitro groups are essentially in the ring planes, and the interplanar angle between the mean planes described by the atoms of the benzoyl substituents and those of the benzoic acid aryl rings are 69(1)° and 84(1)°, respectively. The lower cell volume, higher density, and lower solubility in ethyl ethanoate correlates with the greater packing efficiency in 5-nitro-2-benzoylbenzoic acid.     

The crystal structure of 5-amino-2-nitrobenzoic acid

The crystal structure of 5-amino-2-nitrobenzoic acid (5A2NB) was determined by the X-ray diffraction method. The 5-amino-2-nitrobenzoic acid crystallizes in the monoclinic P2₁/c space group with a = 3.898(2) Å, b = 13.531(3) Å, c = 14.301(3) Å, and = 90.83(3)°. The adjacent molecules form a cyclic dimmer by intermolecular hydrogen bonds of type O—HsO with their carboxyl groups. In the crystal structure NH₂ group forms a three-center hydrogen bond with oxygen atoms of NO₂ group. The IR spectrum and thermal properties of acid are discussed.     

Synthesis and structure of 2-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalene)]-5-benzimidazole ethylcarboxylate monohydrate

As part of a program investigating the conformations of potential anticarcinogens and antioxidants, the structure of the title compound C₂₄H₂₈N₂O₂·H₂O is reported. The monohydrate crystallizes in the monoclinic space group P2/c with unit cell parameters a = 16.184(1),b = 7.937(1), c = 16.968(1), = 92.788(7)°, and Z = 4. The benzimidazole and tetrahydrotetramethylnaphthalene ring systems are inclined to one another by approximately 26°. The water molecule plays an important role in the crystal structure by hydrogen bonding to different functional groups of three organic moieties. Additional crystal stabilization is dueto – stacking of benzimidazole rings.     

Synthesis, characterization, and X-ray crystal structure of di-(2,4-imidazolidinedione-5-ethyl)disulfide, C10H14N4O4S2

Di-(2,4-imidazolidinedione-5-ethyl)disulfide or homocystine hydantoin, C₁₀H₁₄N₄O₄S₂ (I), crystallizes in the non-centrosymmetric space group P2₁ (No. 4) with two molecules in the unit cell with a = 7.132(1), b = 9.282(2), c = 10.770(2) Å and = 105.68(1)°. The two imidazolidinedione rings are planar with a dihedral angle of 46.9°. The rings are joined by a diethyl disulfide bridge at chiral centers on the rings. The C-S-S-C torsion angle is –80°(–sc). The absolute stereochemistry of the chiral centers was determined to be (5S, 5S), = + 0.92 (11). Important bond distances include: S-S = 2.022(4); S-C (mean) = 1.809(8); and C=O (mean) = 1.224(7) Å. The compound is stabilized by a network of intermolecular carbonyl-to-amine hydrogen bonding and van der Waals cohesive forces.     

Polymeric copper(II)-orotato complexes, [(C5H2N2O4)Cu(H2O)2]n

The compound [(C₅H₂N₂O₄)Cu(H₂O)₂]_n has been synthesized and its structure determined at room temperature. The primary coordination sphere at the Cu ion is square planar with the orotate dianion coordinating at the metal through heterocyclic nitrogen atom and adjacent oxygen of the carboxylate group, the remaining coordination sites are occupied by two water molecules. The orotate dianion is tricoordinated to one copper via N₁ and one oxygen of the carboxylato group and to another copper atom via the other oxygen of the carboxylato group. The coordination at copper is extended to five by the other oxygen of the carboxylate group of another orotate molecule. Thus, the molecules are associated to form chains, the carboxylato group acting as a bridge between the metal ions, the orotato-group being tridentate. The title compound crystallizes in the monoclinic space group. P2₁/n₁ with a = 9.515(5), b = 6.925(2), c = 11.861(6) Å, = 95.285(9)°, D _calc = 2.17 g cm^–3, and z = 4.     

Structure of 2-acetoxy-3-(3-methoxy-4-acetoxy-5-chlorophenyl)-propenoic acid

2-Acetoxy-3-(3-methoxy-4-acetoxy-5-chlorophenyl)-propenoic acid 2 was synthesized from the azlactone of 5-chlorovanillin and its structure confirmed by X-ray crystallography and nuclear magnetic resonance methods. Compound 2 crystallized with a molecule of acetic acid in the P-1(#2) space group (Z = 2) and with cell dimensions a = 6.303(2), b = 9.779(1), c = 15.528(3) Å, = 101.46(2), = 100.71(2) and = 90.21(2)°. This study reveals the formation of an -acetoxy propenoic acid with a trans extended side acid side chain conformation. The ¹H and ¹³C NMR spectral values of 2 also show the existence of the enolic ester in solution.     

Mesogenic Properties of 5-Cyanotropolone and 2-Amino-5-Cyanotropone Derivatives

Abstract

New 5-cyanotroponoid liquid crystals with a 3,4-dialkoxybenzoyloxy and a 3,4-dialkoxybenzoylamino substituent at the C-2 position were prepared. These derivatives exhibited interdigitated bilayer smectic A phases while the corresponding benzenoids were non-mesogenic. Thermal stabilities of these troponoids were lower than those of 2-(4-alkoxybenzoyloxy)-5-cyanotropones and 2-(4-alkoxybenzoylamino)-5-cyanotropones.     

Preparation and crystal structure of tungstogallate acid H5GaW12O40

The heteropoly tungstogallate acid H₅GaW₁₂O₄₀ has been synthesized and characterized. Colorless octahedral crystals of the title compound were crystallized from acetonitrile with formula H₅GaW₁₂O₄₀. The single crystal X-ray structure analysis of the title compound revealed that it crystallized in monoclinic system, space group Cm with a = 17.691 (4) Å, b = 25.065 (5) Å, c = 15.315 (3) Å, = 125.21 (3)°, V= 5548.5 (19) ų, and Z = 2. The crystal consists of the heteropolyanion GaW₁₂O ₄₀ ^5– and H⁺ cations. The heteropolyanion GaW₁₂O ₄₀ ^5– is an independent unit and assumed to have the Keggin structure.     

Growth and characterization of 2-amino-5-chlorobenzophenone (2A-5CB) single crystals

Organic nonlinear optical single crystals of 2-amino-5-chlorobenzophenone (2A-5CB) were grown in ethanol by slow solvent evaporation technique. The grown crystals were characterized by single-crystal XRD, FTIR, FT-Raman and UV–vis–NIR techniques. The UV–vis–NIR spectrum ascertains the cut-off wavelength of the sample as 390 nm. The powder second harmonic generation (SHG) technique reveals that 2A-5CB crystal has its SHG efficiency nearly three times that of KDP. The dielectric response of the sample was studied in the frequency region of 50 Hz–1 MHz at varying temperatures. The photoconductivity studies indicate that the 2A-5CB crystal exhibits negative photoconductivity. TGA–DTA studies confirm the melting point of the sample as 101.5 °C.     

Hydrothermal synthesis and structure of a novel terbium coordination polymer with packing cavities, {[Tb(TCB)1/2(H2TCB)1/2(H2O)](H2O)2}n (H2TCB = 1, 2, 4, 5‐benzenetetracarboxylic acid)

A novel terbium coordination polymer {[Tb(TCB)_1/2(H₂TCB)_1/2(H₂O)](H₂O)₂}_n (H₂TCB = 1, 2, 4, 5‐benzenetetracarboxylic acid) ( 1 ) has been hydrothermally synthesized and determined by single crystal X‐ray diffraction method, which features a very interesting three‐dimensional framework with large packing cavities. It crystallizes in the monoclinic space group P2₁/n with a = 1.0723(4) nm, b = 0.7168(3) nm, c = 1.7155(6) nm, β = 97.079(4)°, V = 1.3086(8) nm³, Z = 4, and final R₁ = 0.0203, wR₂ = 0.0404. In 1, the protonated carboxylate groups are free, the other carboxylate groups are bonded to Tb³⁺ ion in three modes: the chelating bidentate, the bridging bidentate and bridging tridentate. Moreover each Tb³⁺ ion is coordinated by nine oxygen atoms from six carboxylate groups and one water molecule respectively to complete a deformed tricapped trigonal prismatic geometry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Growth and Structural Refinements of the Y2SiO5, Y2Si2O7 and LaBSiO5 Single Crystals

The laser crystals of chromium doped yttrium oxyorthosilicate (YSO) were grown from the melt by Czochralski technique. The crystals of YSO, yttrium pyrosilicate and stillwellite-like lanthanum borosilicate were obtained from high temperature solutions. Lithium and potassium di- and trimolybdates were used as fluxes in the growth experiments on silicate crystals. In the case of borosilicate crystals, the choice of fluxes was based on the potassium trimolybdate with an excess of potassium fluoride. The composition of grown crystals was studied by electron microprobe analysis, and structural characteristics were determined for all the single crystals.     

Syntheses,Structural, and Biological Studies of Two New Peptide Compounds, 2(s)-(5-fluorouracil-1-aceto)amino-2-isopropyl Acetate Hemihydrate and 2(s)-(5-fluorouracil-1-aceto)amino-2-isopropyl Acetic Acid

Abstract  Two new peptide compounds, 2(s)-(5-fluorouracil-1-aceto)amino-2-isopropyl acetate hemihydrate (1:1/2H ₂ O) and 2(s)-(5-fluorouracil-1-aceto)amino-2-isopropyl acetic acid (2), have been synthesized and characterized by elemental analysis, IR, ¹H- and ¹³C NMR spectroscopy. Two new compounds were structurally characterized by single-crystal X-ray diffraction. The thermal stabilities of compounds 1:1/2H ₂ O and 2 were studied by DSC-TGA techniques. The result of the biological test showed that the compounds 1:1/2H ₂ O and 2 have certain antitumor activities. Index Abstract  Two new peptide compounds, 2(s)-(5-fluorouracil-1-aceto)amino-2-isopropyl acetate hemihydrate (1:1/2H2O) and 2(s)-(5-fluorouracil-1-aceto)amino-2-isopropyl acetic acid (2), have been synthesized and characterized by elemental analysis, IR, 1H-, and 13C NMR spectroscopy. Two new compounds were structurally characterized by single-crystal X-ray diffraction. The thermal stabilities of compounds 1:1/2H2O and 2 were studied by DSC-TGA techniques. The result of the biological test showed that the compounds 1:1/2H2O and 2 have certain antitumor activities.      

基于2,5-二溴对苯二甲酸配体的锌/钴配合物合成、晶体结构及性质

将有机物2,5-二溴对苯二甲酸(H₂L₁)和2,2′-联吡啶(L₂)作为双配体,使用溶剂热法和七水合硫酸锌(ZnSO₄·7H₂O)、六水合硝酸钴(Co(NO₃)₂·6H₂O)分别反应,得到配合物[Zn(L₁)(L₂)(H₂O)]_n(1)和配合物[Co(L₁)(L₂)(H₂O)]_n(2)。采用单晶X射线衍射、元素分析、红外光谱、紫外光谱、荧光光谱、热重分析等测试方法对这两种物质进行分析研究。单晶测试结果表明配合物1是单斜晶系,以Zn²⁺配位连接L^2-₁与L₂形成一维链状结构,各条链在分子间氢键和π…π共轭作用下有规律地堆叠形成三维网络结构。配合物2是三斜晶系,Co1离子和Co1ⁱ离子由H₂L₁上的羧酸氧原子O4和O4ⁱ连接,形成双齿螯合的配位结构单元,以Co²⁺配位连接 L^2-₁和L₂形成二维网格结构,各层在O—H…O分子间氢键和范德瓦耳斯力作用下有规律的堆叠形成三维网络结构。配合物1和2均含有芳香杂环、羧基杂环和氮杂环,具有良好的荧光性质和热稳定性,最大发射波长分别为345 nm和333 nm。     

Enthalpy and Entropy of Transitions and Texture of (+)-2-Methylbutyl-p ((p-methoxy benzylidene) amino)cinnamate

The results of Differential Scanning Calorimetric and optical studies of (+)-2-methyl-butyl-p ((p-methoxy benzylidene)amino) cinnamate (MB MBAC) are reported. We report an additional solid phase formed on quenching the sample.     

Crystallographic and NMR evidence for the enol tautomer of 3-methoxy-4-hydroxy-5-chloro-phenylpyruvic acid

The structures and conformation of 3-methoxy-4-hydroxy-5-chloro-phenylpyruvic acid3 and its acetate ester4 have been investigated by X-ray crystallography and by spectroscopic methods. Three independent molecules crystallized for the ester4 with the triclinic symmetry and the centrosymmetric space group (Z=6) and with the cell dimensionsa=11.764(6),b=13.549(5),c=13.978(15) Å. =100.08(7), =94.62(8), =115.06(4)°. The three conformers of4 exist as the enolate tautomers and not the keto form.Trans extended side pyruvic acid side chains were observed for the three conformers. The crystalline cohesion was ensured by a strong network of hydrogen bonds. The NMR spectra of the phenylpyruvic acid3 and the acetate ester4 exhibited each a single proton on the benzylic carbon atom and chemical shift values supporting the existence of the enolate tautomer form for these phenylpyruvic acid compounds in solution.     

Crystal structures of the new diphosphates,K2NiP2O7 and K6Sr2Ni5(P2O7)5

Crystalline K₂NiP₂O₇ (I): monoclinic, P2₁,a=9.230(2),b=17.540(8),c=8.319(9)Å, =91.44(2)°,Z=8,d _calc=3.067 g cm^–3, MoK =0.71069Å,R/R _w=6.5/9.4%, is characterized by the existence of face sharing NiO₆ octahedra with Ni–Ni separation of 2.827 Å (Ni–O; 1.93(2)–2.17(2)Å). K⁺ is seen in sites of seven, six, and fivefold coordination (K–O, averages; 2.83(2), 2.81(2), and 2.77(2)Å, respectively) P₂O₇ ^4– groups are observed in semieclipsed conformation. K₆Sr₂Ni₅(P₂O₇)₅ (II) crystallizes in monoclinic space group P2₁/c;a=11.038(7),b=9.533(13),c=7.438(2)Å, =100.13(4)°,D _calc=3.309 g cm^–3,Z=2,R/R _w=6.4/8.1%. Nickel atoms are distributed on planes parallel to the crystallographic (100) plane at =0 and =0.5. On the planes, =0, Ni²⁺ ions form successive linked trimers of edge sharing NiO₆ octahedra (Ni–Ni, 3.018(1), 3.008(1)Å; Ni–O, av 2.07(2)Å). The intermediate planes (=0.5) contain isolated and six coordinate Ni²⁺ ions (Ni–O av. 2.09(2)Å). Seven-coordinate potassium ions (K–O, av. 2.74(2)Å) are located on intermediate planes at =0.25 and 0.75. P₂O₇ ^4– groups are found in eclipsed conformation. Strontium atoms are located between nickel and potassium planes and are surrounded by seven oxygen atoms (Sr–O, av. 2.586(2)Å).