Influence of solvents on the hydrothermal formation of one‐dimensional magnesium hydroxide

The influence of solvents on the hydrothermal formation of one‐dimensional (1D) magnesium hydroxide (Mg(OH)₂) was investigated in this paper. Uniform 1D Mg(OH)₂ with a length of 10‐20 μm, a width of 100‐200 nm and a preferential growth along [110] direction have been synthesized by treating magnesium oxysulfate (5Mg(OH)₂·MgSO₄·3H₂O, abbreviated as 513MOS) nanowires in NaOH ethanol solution at 180 °C for 2.0 h. The experimental results indicated that the solvent of ethanol and NaOH concentration were essential for the conversion of 513MOS nanowires to 1D Mg(OH)₂. The slow release of MgSO₄ from 513MOS and the heterogenous precipitation of Mg(OH)₂ at the defects left by MgSO₄ dissolution promoted the formation of 1D Mg(OH)₂. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of alcohols additives on hydrothermal formation of magnesium hydroxide sulfate hydrate whiskers

Two different organic alcohols, ethylene glycol and 1, 2‐propanediol, were used in hydrothermal formation of MgSO₄·5Mg(OH)₂·2H₂O (MHSH) whiskers. Compared with the MHSH whiskers without alcohols, the crystallinity and defect of products were improved. It could also be observed that not only aspect ratio but also crystallinity and purity of the products were improved when 1, 2‐propanediol was used. A reasonable model was proposed to explain the growth process derived from the organic alcohol. In addition, the room temperature photoluminescence (PL) indicated that the spectrum intensity of MHSH whiskers used 1, 2‐propanediol was also significantly improved.     

The effects of solvent and microwave on the preparation of Magnesium Oxide Precursor

Four methods including hydrothermal method, glycol‐hydrothermal method, microwave‐hydrothermal method and glycol‐microwave‐hydrothermal method were used to prepare magnesium oxide precursor by the reaction of MgSO₄·7H₂O with (NH₄)₂CO₃. The composition, crystallinity, morphology, aspect ratio, yield, functional groups, atom distribution, and interplanar spacing of the sample were investigated by X‐ray diffraction (XRD), Scan Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT‐IR), and High Resolution Transmission Electron Microscope (HRTEM). The properties of Magnesium Oxide precursor were compared with each other. The results of FT‐IR and XRD showed that the crystals were all nesquehonite. However, it was shown by FT‐IR results that the crystals prepared by glycol‐microwave‐hydrothermal method contained OH⁻ and HCO₃⁻ groups, which indicated that the Mg(OH)(HCO₃)·2H₂O type crystals would be facilitated by this method. The glycol‐hydrothermal method can create high quality Magnesium Oxide precursor with a high degree of crystallinity, high purity, high aspect ratio, smooth surface, and good dispersibility.     

Hydrothermal synthesis and formation of 4ZnO·B2O3·H2O whiskers via a new route

4ZnO·B₂O₃·H₂O whiskers were prepared from 2ZnO·3B₂O₃·3.5H₂O under hydrothermal process at 160 °C for 10 h. The synthesized product was characterized by XRD, SEM, TG‐DSC and FT‐IR. SEM results showed that the synthesized 4ZnO·B₂O₃·H₂O whiskers' length was about 3–10 μm and the diameter was 0.2–0.3 μm. Further study on the whiskers' growth process and mechanism showed that the formation of the whiskers went through three stages and the morphology of 4ZnO·B₂O₃·H₂O changed from irregular particles to rod‐like structures and finally to whiskers. The variation of the morphology of the 4ZnO·B₂O₃·H₂O whisker with the concentration of the starting material was investigated. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Structural and spectroscopic study of Mg13.4(OH)6(HVO4)2(H0.2VO4)6

Single‐crystals of the polar compound magnesium hydrogen vanadate(V), Mg_13.4(OH)₆(HVO₄)₂(H_0.2VO₄)₆, were synthesized hydrothermally. It represents the first hydrogen vanadate(V) among inorganic compounds. Its structure was determined by single‐crystal X‐ray diffraction [space group P 6₃mc, a = 12.9096(2), c = 5.0755(1) Å, V = 732.55(2) ų, Z = 1]. The crystal structure of Mg_13.4(OH)₆(HVO₄)₂(H_0.2VO₄)₆ consists of well separated, vacancy‐interrupted chains of face sharing Mg2O₆ octahedra, with short Mg2—Mg2 distances of 2.537(1) Å, embedded in a porous magnesium vanadate 3D framework having the topology of the zeolite cancrinite. All three hydrogen positions in the structure were confirmed by FTIR spectroscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and crystal strcucture of two zinc inclusion complexes

X‐ray single crystals of these two inclusion complexes, [Zn(H₂O)₄L₂]·(4‐amino‐1‐naphthalene sulfonate)₂ (L = 1,3‐bis(4‐pyridyl) propane), 1 , and [Zn(H₂O)(bipy)₂]·(4‐amino‐1‐naphthalene sulfonate)(NO₃) (bipy = 4,4'‐bipyridine), 2 were achieved by the reaction of Zn(NO₃)₂ and 4‐amino‐1‐naphthalene sulfonate to 1,3‐bis(4‐pyridyl) propane and 4,4'‐bipyridine, respectively. As inclusion complexes, the cationic components of 1 and 2 were formed by two infinite zigzag chains, while, 4‐amino‐1‐naphthalene sulfonate made up the anionic parts of these two complexes. Thus, the whole molecules of these two complexes are neuter. Numous hydrogen bonds could be found in these two inclusion complexes, which help them to form three‐dimensional solid‐state packing structure architectures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Room‐temperature synthesis and characterization of cross‐like Pr2(C2O4)3·10H2O micro‐particles

Cross‐like Pr₂(C₂O₄)₃·10H₂O micro‐particles were synthesized through a simple precipitation method at room temperature. The products were characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FESEM), thermogravimetry–differential thermal analysis (TG‐DTA) and photoluminescence (PL). The possible formation mechanism of the cross‐like Pr₂(C₂O₄)₃·10H₂O micro‐particles was discussed, and Pr₆O₁₁ with similar morphology was obtained by calcining the oxalate precursor. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystallization and Characterization of Orthorhombic β‐MgSO4 · 7H2O

In solution, the growth rate and the crystal habit are influenced by a number of factors such as supersaturation, temperature, pH of the solution, cooling rate, agitation, viscosity, initial state of the seed crystal and the presence of impurities. The crystallization of orthorhombic β‐MgSO₄ · 7H₂O, from low temperature aqueous solution by slow cooling process was studied. The metastable zone width, the induction periods (τ) for different supersaturations and the effect of pH on the growth rate of the crystals were investigated. The increase of pH yielded bigger crystals. The structural, optical, thermal and mechanical properties of β‐MgSO₄ · 7H₂O have been studied using FT‐IR, X‐ray diffraction, TGA‐DTG and micro hardness analyses.     

Synthesis of magnesium borates using sodium borate and magnesium sulfate

Synthesis conditions of magnesium borate compounds in aqueous medium using Na₂B₄O₇ · 10H₂O and MgSO₄ · 7H₂O were determined. The effects of B/Mg mole ratio, pH, reaction time and precipitation temperature on the reaction performed at 90 °C were examined. 0.04Na₂O · MgO · 1.23B₂O₃ · 3.42H₂O and 0.06Na₂O · MgO · 1.65B₂O₃ · 3.34H₂O were synthesized at optimum B/Mg mole ratios of 3.60 and 4.80 by precipitation at 5 °C and the amorphous compounds formed were identified by B, Mg, Na and XRD analyses and some physical tests.     

Synthesis and crystal structure of 3-ammonium-4-hydroxyphenyl sulfonate hemihydrate

The crystal structure of 3-ammonium-4-hydroxyphenyl sulfonate hemihydrate C₆H₃(NH₃)(OH)SO₃ · 0.5H₂O is determined by single-crystal X-ray diffraction. The unit cell parameters are as follows: a = 11.2395(3), b = 10.3814(3), c = 13.7509(4) Å, β = 100.326(1)°, V = 1578.49(8) ų, space group P2₁/n, Z = 4. The crystal structure can be described us a succession of infinite corrugated layers parallel to ab plane. These layers consist of rings formed by four sulfonate molecules located around a center of symmetry. The rings are connected to each other and to water molecules via O-H...O hydrogen bonds. The structure is further stabilized by π-π interactions between phenyl rings of organic entities of successive layers.     

Composition and morphology control of Fex(PO4)y(OH)z·nH2O microcrystals

A series of Fe_x(PO₄)_y(OH)_z·nH₂O microcrystals were prepared by the hydrothermal reaction at 150 °C. The ratio of Fe²⁺/Fe³⁺ in Fe_x(PO₄)_y(OH)_z·nH₂O microcrystals can be adjusted by using Na₂S₂O₃·5H₂O as a reducing agent. The morphology control of Fe_x(PO₄)_y(OH)_z·nH₂O microcrystals was realized through regulating the molar ratio of LiAc·2H₂O/FeCl₃. Further, the morphology, structure and composition of Fe_x(PO₄)_y(OH)_z·nH₂O microcrystals were also investigated by x‐ray diffraction (XRD), x‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Two CrIII containing metal‐1‐hydroxyethylidenediphosphonate compounds: Synthesis,structure, and morphology

Two novel layered Cr^III containing metal‐hedp compounds, Na₂₀AlCr^III[CH₃C(O)P₂O₆]₆·O₃·(H₂O)₂₆·(H₃O)₁₀ (CH₃ CH₂ OH) and Na₆Cr^III[CH₃C(OH)P₂O₆]₃·(H₂O)₂₁(H₃O)₃ (designated as DLES‐AlCr and DLES‐Cr^III respectively), were hydrothermally synthesized. Their structures were determined by single‐crystal X‐ray diffraction. The two crystals are isostructural with propeller‐like chiral motifs and hexagonal rings along [001]. DLES‐AlCr crystal exhibits interesting hollow tubular hexagonal morphology, while DLES‐Cr crystal possesses solid hexagonal morphology. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Hydrogen Bonding Patterns in 2,6-diamino-4-oxopyrimidinium Sulfosalicylate Monohydrate

The title compound, [C₄H₇N₄O⁺, C₇H₅O₆S^? . H₂O] contains one 2, 6-diamino-4-oxopyrimidinium cation, one sulfosalicylate anion and a water molecule. The crystal structure was determined by single crystal X-ray diffraction. This compound crystallized in the orthorhombic system; space group Pna2₁ with the unit cell parameters a = 13.402(3) Å, b = 16. 221(3) Å, c = 6.714(2) Å, V = 1459.6(6), Z = 4. The sulfonic acid group has protonated the aminopyrimidine moiety. The protonated N1 atom and N4 amino group are hydrogen bonded to the keto group (O1) of the neighbouring pyrimidine forming a six-membered ring with graph-set notation R₂ ¹(6) and a supramolecular chain along the c-axis. This supramolecular chain is further strengthened by one of the sulfonate oxygen atoms (O3), bridging the pyrimidines via hydrogen bonded rings, R₃ ²(10) involving N(3)–H(3)···O(3) and N(2)–H(2B)···O(3) hydrogen bonds. The other two oxygen atoms of the sulfonate groups are bridged by water molecules via O-H···O hydrogen bonds constituting a supramolecular chain. The water molecule also acts as hydrogen bond acceptor with respect to the carboxyl group.     

Synthesis and Crystal Structure of a New Schiff Base 4-[(2-hydroxy-benzylidene)-amino]-<Emphasis Type="Italic">N</Emphasis>-(5-methyl-isoxazol-3-yl)-benzenesulfonamide

Abstract  The structure of the title compound (C₁₇H₁₅N₃O₄S)₂ the schiff base, bis(N-(5-methyl-3-isoxazolyl)-4-[(2-hydroxy benzylidene)-amino]) benzene sulfonamide was elucidated by H¹, C¹³ NMR, UV–VIS and IR spectroscopic techniques. The X-ray structure was determined in order to establish the conformation of the molecule. The compound crystallizes in the triclinic space group P-1, with a = 11.419(1), b = 11.426(0), c = 13.316(1) ?, α = 71.94(2), β = 89.79(1), γ = 89.14(2)° and Z = 4. Two benzene rings and azomethine group are practically coplanar, as a result of intramolecular hydrogen bonds involving the hydroxy O atom and azomethine N atom. The component species further interact via N–H···N and C–H···O hydrogen bonds and π–π stacking interactions. Index Abstract  The title compound (C₁₇H₁₅N₃O₄S)₂, Schiff base, bis(N-(5-methyl-3-isoxazolyl)-4-[(2-hydroxy benzylidene)-amino]) benzene sulfonamide was synthesized by the condensation of 4-amino-N-(5-methyl-3-isoxazolyl) benzene sulfonamide (SMZ) and 2-hydroxy benzaldehyde (SA). Its structure was confirmed by single crystal X-ray diffraction analysis. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Syntheses,Structures and Optical Properties of a Series of Lanthanide Complexes with Chelidamic Acid and 4,4′-Bipyridyl

Abstract  

The title complexes, (C₁₀H₈N₂)·[Y(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·3H₂O (1), (C₁₀H₈N₂)·[Er(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·3H₂O (2), (C₁₀H₈N₂)·[La(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·4.5H₂O (3), (C₁₀H₈N₂)·[Sm(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·4.75H₂O (4), (C₁₀H₈N₂)·[Pr(C₇H₃NO₅)(C₇H₄NO₅)·2H₂O]·4.75H₂O (5) were synthesized and characterized by X-ray single-crystal diffraction. The crystal structures of 1–2 reveal that they are isomorphous, among which the metal atoms are all eight-coordinate with a distorted dodecahedron coordination geometry. The structures of 3–5 are isomorphic, among which the metal atoms are all nine-coordinate with distorted tricapped trigonal prismatic coordination geometries by two chelidamic acid ligands. Complexes 1–5 are formed into 3D networks by H-bonds. The optical properties of 1–5 were investigated in terms of fluorescent spectra, which all exhibit strong luminescence.     

Spray pyrolysis deposition and characterization of highly (100) oriented magnesium oxide thin films

Transparent dielectric thin films of MgO has been deposited on quartz substrates at different temperatures between 400 and 600°C by a pneumatic spray pyrolysis technique using Mg(CH₃COO)₂·4H₂O as a single molecular precursor. The thermal behavior of the precursor magnesium acetate is described in the results of thermogravimetry analysis (TGA) and differential thermal analysis (DTA). The prepared films are reproducible, adherent to the substrate, pinhole free and uniform. Amongst the different spray process parameters, the substrate temperature effect has been optimized for obtaining single crystalline and transparent MgO thin films. The films crystallize in a cubic structure and X‐ray diffraction measurements have shown that the polycrystalline MgO films prepared at 500°C with (100) and (110) orientations are changed to (100) preferred orientation at 600°C. The MgO phase formation was also confirmed with the recorded Fourier Transform Infrared (FTIR) results. The films deposited at 600°C exhibited highest optical transmittivity (>80%) and the direct band gap energy was found to vary from 4.50 to 5.25 eV with a rise in substrate temperature from 500 to 600°C. The measured sheet resistance and the resistivity of the film prepared at 600°C were respectively 10¹³Ω/□ and 2.06x10⁷Ω cm. The surface morphology of the prepared MgO thin films was examined by atomic force microscopy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Precipitation of nesquehonite from homogeneous supersaturated solutions

The homogeneous (unseeded) precipitation of nesquehonite (MgCO₃·3H₂O) was studied over the temperature range of 10‐40 °C. Precipitation was triggered by the supersaturation created by mixing MgCl₂ solution (0.5‐1.5 M) with Na₂CO₃ solution in the same concentration range. The Meissner's method was adopted in the calculation of supersaturations during the MgCl₂‐Na₂CO₃ reaction to monitor the precipitation. Solids were identified using X‐ray diffraction (XRD) analysis and scanning electron microscope (SEM) images. In the temperature range of 10‐40 °C, MgCO₃·3H₂O with needle‐like or gel‐like morphology was precipitated. It was seen that the length, width and surface smoothness of the particles changed with reaction temperature and supersaturation. The supersaturation (S) was in the range of 1.09‐58.68 during titration of Na₂CO₃ solution. The dimension of the crystals increased with longer addition time (or lower initial concentration of reactant) at the same temperature. Slower addition via titration of 2 h followed by 2 h of equilibration at 40 °C proved successful in producing well developed needle‐like MgCO₃·3H₂O crystals of 30‐50 μm long and 3‐6 μm wide. MgCO₃·3H₂O obtained were calcined to produce highly pure magnesium oxide (MgO) at 800 °C. The morphology of MgO was similar to that of their corresponding precursors. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal and molecular structure of 1‐allyl‐5‐(4‐methylbenzoyl)‐4‐(4‐methylphenyl)pyrimidine‐2(1H)‐thione

The crystal structure of 1‐allyl‐5‐(4‐methylbenzoyl)‐4‐(4‐methylphenyl)pyrimidine‐2(1H)‐thione (C₂₂H₂₀N₂OS) has been determined from three dimensional single crystal X‐ray diffraction data. The title compound crystallizes in the monoclinic space group P 2₁/c, with a = 10.6674(13), b = 10.1077(7), c = 17.9467(19) Å, β = 98.460(9)°, V = 1914.0(3) ų, D_calc = 1.251 g cm^–3, Z = 4. In the title compound, the allyl group shows positional disorder. Molecules are linked by C‐H···O, C‐H···N and C‐H···S intermolecular interactions forming two‐dimensional network. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystallization and characterization of nonlinear optical l‐histidinium dihydrogen orthophosphate orthophosporic acid single crystal

L‐histidinium dihydrogen orthophosphate orthophosporic acid (abbreviated as LHP) with molecular formula C₆H₁₀N₃O₂⁺·H₂PO₄^‐·H₃PO₄ was successfully grown by slow evaporation technique from aqueous solution. The crystal was characterized by X‐ray diffractometry (XRD), UV‐Vis‐NIR, TGA, DTA, microhardness and solubility studies. The dielectric constant and dielectric loss of the crystal were studied as function of frequency. Photoconductivity studies were also carried out on the sample. The SHG efficiency of the crystal is studied using the Kurtz and Perry technique. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of (<Emphasis Type="Italic">E</Emphasis>)-3-fluoro-N-((5-nitrothiophen-2-yl)methylene)aniline

The structure of the title compound C₁₁H₇FN₂O₂S was characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n with Z = 12, i.e. with three molecules in asymmetric unit. The molecules are not planar: the dihedral angles between the planes of thiophene and the benzene rings are 42.3(3)°, 42.0(3)°, and 48.9(2)°. In the crystal, intermolecular C–H···F interactions link the molecules through R₂² (14) ring motif. The crystal packing is also stabilized by π···π interactions.