Synthesis and crystal structure of the coordination compound of pyridoxine with manganese sulfate

The reaction of pyridoxine with manganese sulfate in an aqueous solution gave the coordination compound MnSO₄ · 2C₈H₁₁O₃N · 2H₂O (I). The structure of I was determined from single-crystal X-ray diffraction data. In the centrosymmetric complex (sp. gr. P[`1]P\bar 1, Z = 1), the Mn atom is coordinated by two pyridoxine molecules and two water molecules, thus adopting an octahedral coordination. The sulfate anion is also at a center of symmetry and, consequently, is disordered. The pyridoxine molecules are coordinated to the metal atom through the oxygen atoms of the deprotonated hydroxyl group and the CH₂OH group that retains the hydrogen atom. The nitrogen atom is protonated in such a way that the heterocycle assumes a pyridinium character. The crystal structure also contains six water molecules of crystallization. A thermogravimetric study showed that the decomposition of I occurs in several successive steps, such as dehydration, the combustion of organic ligands, and the formation of an inorganic residue.     

Synthesis and crystal structures of four nickel(II) 1,5-naphthalenedisulfonate compounds

Four nickle(II) 1,5-naphthalenedisulfonate (1,5nds) complexes, namely [Ni(H₂O)₆] (1,5nds) (1), trans-[Ni(en)₂(H₂O)₂](1,5nds)·2H₂O (2), [Ni(tren)(H₂O)₂](1,5nds)·H₂O (3), and [Ni(dien)₂](1,5nds)·2H₂O (4), where en = ethylenediamine, tren = tris(2-aminoethyl)amine, and dien = diethylenetriamine, have been synthesized and structurally characterized. Compound 1 crystallizes in space group P2₁/c, with a = 13.200(2) Å, b = 6.6197(10) Å, c = 9.6001(14) Å, and = 92.005(3)° compound 2 crystallizes in space group C2/c, with a = 15.698(2) Å, b = 13.006(2) Å, c = 12.845(2) Å, and = 119.262(4) Å compound 3 crystallizes in space group P , with a = 8.8971(10) Å, b = 11.5440(13) Å, c = 11.9169(14) Å, = 77.254(2)°, = 74.079(2)°, and = 82.162(2)° compound 4 crystallizes in space group P2₁/c, with a = 10.3600(13) Å, b = 12.5650(16) Å, c = 9.9853(12) Å, and = 103.599(2)°. Compound 1 crystallizes in a typical inorganic–organic layered structure adopted by metal naphthalenesulfonate, while compounds 2–4 crystallize in a hybrid inorganic–organic pattern. Unlike their Cu²⁺ analogue, the sulfonate does not coordinate directly to Ni²⁺. The hydrogen bonds formed between sulfonate and water molecules are the predominant packing forces for all structures. The inherited inversion center of the 1,5nds anion is carried into the crystal structure and results in centrosymmetric crystallization of all compounds.     

The syntheses and crystal structures of two chromium(III) and molybdenum(III) coordination compounds with 4-ethylpyridine

The structures of trichlorotris(4-ethylpyridine)chromium(III), [CrCl₃(C₇H₉N)₃] (I), and trichlorotris(4-ethylpyridine)molybdenum(III), [MoCl₃(C₇H₉N)₃] (II), consist of neutral molecules where three 4-ethylpyridine and three chloro ligands coordinate to the metal with a meridional configuration. Compound I crystallizes in a trigonal space group P3₁ with a = 11.515(2) Å and c = 15.378(3) Å. Compound II crystallizes in a monoclinic space group C2/c with a = 24.200(3) Å, b = 18.089(3) Å, c = 22.6004(7) Å and = 106.7137(6)°.     

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)     

Optimization of control parameters of cadmium zinc telluride Bridgman single crystal growth

The temperature gradient within a furnace chamber and the crucible pull rate are the key control parameters for cadmium zinc telluride Bridgman single crystal growth. Their effects on the heat and mass transfer in front of the solid‐liquid interface and the solute segregation in the grown crystal were investigated with numerical modeling. With an increase of the temperature gradient, the convection intensity in the melt in front of the solid‐liquid interface increases almost proportionally to the temperature gradient. The interface concavity decreases rapidly at faster crucible pull rates, while it increases at slow pull rates. Moreover, the solute concentration gradient in the melt in front of the solid‐liquid interface decreases significantly, as does the radial solute segregation in the grown crystal. In general, a decrease of the pull rate leads to a strong decrease of the concavity of the solid‐liquid interface and of the radial solute segregation in the grown crystal, while the axial solute segregation in the grown crystal increases slightly. A combination of a low crucible pull rate with a medium temperature gradient within the furnace chamber will make the radial solute segregation of the grown crystal vanish. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and crystal structures of aluminum and iron phosphites

The hydrated forms of aluminum and iron phosphite were prepared and their structure was solved using X-ray powder diffraction data. The diffraction data for the aluminum phosphite powder sample was collected using synchrotron radiation(=1.3087 Å) while that for iron phosphite was obtained from a rotating anode X-ray source. Both compounds crystallize in the monoclinic space group, P2₁. Unit cell parameters for the Al compound:a+8.0941(1),b+9.9137(1),c+7.6254(1) Å, =111.95°; Fe compound:a+8.2548(1),b+10.1814(1),c+7.7964(1) (Å), =111.94(1)°. The Rietveld refined formula is M₂(PO₃H)₃·4H₂O (M=Al, Fe). There are two independent metal atoms in the structure and both are six-coordinated. One of them is coordinated by two water molecules and four phosphite oxygens. The other atom is surrounded by one water molecule and five phosphite oxygens. All the phosphite oxygens are involved in bridging the Al atoms. The geometry about Al, Fe, and P atoms is normal and they display, expected bond parameters. The Lattice water is located in the cavity and is hydrogen bonded to phosphite oxygen and water molecules.     

Synthesis,structures, and luminescent properties of a series of coordination compounds based on O,N-donor ligands

Four novel coordination compounds, namely, [Cd₂(pydc)₂(bpp)₂(H₂O)₂]? bpp?2H₂O (1), [Zn(Hpydc)₂]?3H₂O (2), [Cd(dhb)₂(phen)₂] (3), and [Zn(L)(phen) (H₂O)] (4) (H₂pydc?=?2,6-pyridinedicarboxylic acid, Hdhb?=?2,6-dihydroxybenzoic acid, H₂L?=?5-((2'-cyano-1,1'-biphenyl-4-yl) methoxy)isophthalic acid, bpp?=?1,3-bis(4-pyridyl)propane, and phen?=?1,10-phenanthroline) have been hydrothermally synthesized and characterized by IR spectroscopy, thermogravimetric analysis and X-ray single crystal diffraction analyses. Compounds 1, 2 and 3 feature zero-dimensional (0D) structures and 1 is further extended to one-dimensional (1D) chain structure through C-H???O hydrogen bonding interactions. Compound 4 exhibits 1D chain structure. The luminescent properties of compounds 3 and 4 have also been studied.     

Synthesis,growth mechanism and optical characterization of zinc nitride hollow structures

In this report, we describe the noncatalytic and template-free synthesis of zinc nitride (Zn₃N₂) novel microstructures with hollow interiors via simple nitridation reaction of zinc powder at optimum temperature of 600° C for 120 min in ammonia gas environment under atmospheric pressure. Hollow microstructures obtained were mostly of spherical shape with diameters in the range 8–35 μm and with open mouth on the surface. The growth mechanism has been proposed for the elucidation of hollow structures formation. Crystal structure and phase purity of the product were investigated by X-ray diffraction (XRD) characterization and energy dispersive X-ray spectroscopy (EDS) analysis confirmed the chemical composition of the product. Morphology of the as-prepared product was investigated using scanning electron microscopy (SEM). Ultraviolet–visible–near infrared (UV–vis–NIR) spectrophotometry was used to study the transmittance behaviour of zinc nitride microstructures and thereby an indirect optical band gap of 2.81 eV was calculated using Davis–Mott model. Room temperature photoluminescence (PL) studies exhibited two prominent peaks of the product; one very strong peak near band edge UV emission (395 nm) and other comparatively suppressed and broad peak at orange luminescence emission (670 nm).     

Synthesis, crystal structures, and properties of copper complexes with tripodal ligands and azide anion

Two new Cu^II complexes, (CuL¹N₃)ClO₄ (1) and (CuL²N₃)ClO₄ (2), have been synthesized and characterized in the presence of NaN₃, where L¹ = tris[2-(6-methylpyridyl)methyl]amine and L² = tris[(3,5-dimethylpyrazol-l-yl)methyl]amine, and their crystal structures have been determined by X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group P–1, with a = 8.258(2) Å, b = 11.481(2) Å, c = 14.158(3) Å, = 72.30(3)°, = 79.05(3)°, = 86.08(3)°, V = 1255.4(5) ų. Compound 2 crystallizes in the monoclinic space group C2/c, with a = 26.752(2) Å, b = 10.561(2) Å, c = 21.059(4) Å, = 120.51(3)°, V = 5126(3) ų. In both compounds, each Cu^II center is in a distorted trigonal–bipyramidal coordinated environment with four nitrogen atoms from the tripodal ligand and one nitrogen atom from the azide group. The coordination geometry around Cu^II center of 1 is axially compressed trigonal bipyramid, while that of 2 is an axially elongated trigonal bipyramid. The coordinated azide group is in the axial site in both complexes. A quasi-dimeric structure of 1 has been formed in the unit cell through hydrogen bonding. The electronic spectra of two complexes in solution have been further studied by UV–vis technique, and the coordination properties have been discussed.     

The translational and inversion pseudosymmetry of the atomic crystal structures of organic and organometallic compounds

The translational and inversion pseudosymmetry of 211162 atomic crystal structures from the Cambridge Structural Database have been investigated.     

Molecular and crystal structures of dibenzenehemiporphyrazine complexes with dimethylformamide

The crystal structures of the 1: 1 and 1: 2 complexes between dibenzenehemiporphyrazine (I) and dimethylformamide (compounds II and III, respectively) are determined by X-ray diffraction. In both compounds, the macrocycle has a saddlelike shape. In III, the conformation of the macrocycle approximates the C _2v symmetry, which agrees closely with the results of quantum-chemical calculations for isolated molecule I and complex II. The ring conformation in crystal II is distorted under the effect of intermolecular interactions, as is evidenced by short intermolecular contacts. The complexes are stabilized by intermolecular N-H?O and C-H?O hydrogen bonds between the hydrogen atoms situated inside the cavity of the macrocycle and the oxygen atoms of the dimethylformamide molecules.     

Generation of crystal structures of heteromolecular compounds by the method of discrete modeling of packings

Within the method of discrete modeling of packings, an algorithm of generation of possible crystal structures of heteromolecular compounds containing two or three molecules in the primitive unit cell, one of which has an arbitrary shape and the other (two others) has a shape close to spherical, is proposed. On the basis of this algorithm, a software package for personal computers is developed. This package has been approved for a number of compounds, investigated previously by X-ray diffraction analysis. The results of generation of structures of five compounds—four organic salts (with one or two spherical anions) and one solvate—are represented.     

Etch figures and crystal structures

The etch figures on some of the naturally occurring faces of crystals of sodium chloride, cuprite, alpha-quartz, tourmaline and topaz are compared with the atomic arrangements on the etched surfaces. The etch figures are influenced in their shape and orientation relative to the natural faces by a number of factors. One of these factors is the crystal structure. In every example of an etched pit bounded by straight edges, it was found that there exists in the crystal structure a continuous chain of relatively strong inter-atomic bonds, running parallel to the straight edge. The study of tourmaline indicates the direction in which all the SiO₄ tetrahedra are pointing relative to the external form.     

The stereochemistry of organosulfur compounds. XX. The x-ray crystal and molecular structures of two tetrathiaspiroalkanes

The X-ray crystal structures of 1,4,6,9-tetrathiaspiro[4.4]nonane (4) and 1,5,7,11-tetrathiaspiro[5.5]undecane (3) have been determined. Crystals of4 are tetragonal, space groupI4₁ cd, with eight molecules in a unit cell of dimensionsa=9.521 (2) andc=19.052(5) Å. Crystals of3 are orthorhombic,Pbca, with eight moleucles in a cell havinga=8.955(3),b=12.356(4), andc=18.425(4) Å. Compound4 was solved from the Patterson map and3 by use ofMultan, and they refined to finalR values of 6.4 and 2.5%, respectively. Compound4 consists of two 1,3-dithiolane rings connected via C(2), both of which appear to be somewhat disordered at room temperature. The uncorrected C-C distance is 1.476 Å and the average S-C distance is 1.786 Å. Compound3 consists of two 1,3-dithiane rings connected at C(2), both in chair conformations. In both compounds there appear to be electronic repulsions between S lone pairs and axial hydrogens of the opposite ring system. Analysis of endocyclic torsion angles in3 indicates that the ring conformations themselves are not significantly altered by the positional shift caused by the repulsion.     

Synthesis, characterization, and crystal structures of two strained cyclic diacetylenes and their precursors

The synthesis, characterization, and crystal structures of two novel strained cyclic diacetylenes are reported. A discussion is presented about the relative bond distances of the diacetylenes compared to a previously reported strained cyclic diacetylene to further determine the degree of aromaticity of that compound. 1,2:5,6:9,10:13,14-Tetrabenzo-3,7,11,15,17-pentadehydro[18] annulene (5) is triclinic, P ^–1, with = 9.489(5), b = 10.550(5), c = 12.155(6) Å, = 100.50(4), = 106.50(4), = 100.85(4)°. 1,2:5,6:9,10:13,14:17,18-Pentabenzo-3,7,11,15,19,23,25-heptadehydro[26]annulene (7) is triclinic, P ^–1, with a = 9.611(2), b = 10.388(3), c = 15.963(3) Å, = 88.67(2), = 76.25(1), = 68.69(2). In addition, two precursors of 5, 3 and 4 which have a helical twist, are reported. [1,2-ethynediyl-bis(2,1-phenylene-2,1-ethynediyl-2,1-phenylene-2,1-ethynediyl]bis[trimethyl-silane] (3) is monoclinic, P2₁/c, with a = 13.682(4), b = 9.787(2), c = 13.448(4) Å, = 112.37(2)°. 1,1-(1,2-ethynyldiyl)bis[2-[(2-ethynylphenyl)ethynyl]-benzene (4) is monoclinic, P2₁/n, with a = 15.951(3), b = 3.999(1), c = 18.168(4) Å, = 99.05(3)°.     

Synthesis and crystal structures of quadruply carboxylate-bridged dimeric lanthanide(III) complexes of betaine

Three dimeric lanthanide(III) complexes, [Eu₂(bet)₈(H₂O)₄](CIO₄)₆ (1), [Tb₂(bet)₈(H₂O)₄](ClO₄)₆ (2), and [Eu₂(bet)₄(H₂O)₈] Cl₆·6H₂O (3) (bet = Me₃N⁺CH₂COO^–, trimethyl-aminoacetate), have been prepared and structurally characterized by X-ray crystallography. Complex 1 crystallizes in the monoclinic space group P2₁/c, with a = 11.7807(8), b = 27.757(5), c = 11.7980(8) Å, = 99.500(4)°, V = 3805.1(8) ų, and Z = 2. Complex 2 is isomorphous to complex 1, crystallizing in the monoclinic space group P2₁/c, with a = 11.7769(14), b = 27.725(3), c = 11.795(5) Å, = 99.668(14)°, V = 3797(2) ų, and Z = 2. Complex 3 crystallizes in the orthorhombic space group Pbca, with a = 12.5664(8), b = 17.8645(9), c = 22.2573(8) Å, V = 4996.6(4) ų and Z = 4. Both complexes 1 and 2 comprise quadruply carboxylate-O,O-bridged [M₂(bet)₄]⁶⁺ dimeric cores (M = Eu, Tb), and each metal ion is further coordinated by two terminal aqua ligands and two monodentate bet carboxylates to form a distorted square-antiprismatic coordination geometry. Complex 3 also has a [Eu₂(bet)₄]⁶⁺ core, in which two bet ligands act in the ¹:¹:₂ bridging fashion, and the other two bet ligands in the less common ²:¹:₂ bridging fashion, namely bridging-chelate mode. Each europium(III) ion in complex 3 is further coordinated by four water molecules to complete a monocapped square antiprism.     

Synthesis, crystal structures, and properties of two manganese(II)-nitroprusside complexes

Two new manganese(II)-1,10-phenanthroline-nitroprusside complexes, [Mn(phen)₃][Fe (CN)₅(NO)]⋯2H₂O⋯0.25CH₃OH (1) and [Mn(phen)₂(H₂O)₂][Fe(CN)₅(NO)]⋯H₂O (2) (where phen is 1,10-phenanthroline) have been synthesized and characterized by X-ray diffraction, electronic paramagnetic resonance (E.P.R.) and IR analyses. Complex 1 crystallizes in the monoclinic space group P2₁/n, with lattice parameters a = 10.0441(15) Å, b = 19.668(2) Å, c = 19.938(3) Å,  β =100.427(14)°, V = 3873.7(10) ų, Z = 4; complex (2) crystallizes in the monoclinic space group C2/c, with a = 17.120(2) Å, b = 13.7925(19) Å, c = 14.4362(17) Å, β = 107.962(12)°, V = 3242.6(7) ų, Z = 4. In the two compounds, three phen ligands 1, or two phen ligands and two cis-related aqua molecules 2, are in a distorted octahedral arrangement around the Mn(II) ion. The nitroprusside anion, [Fe(CN)₅(NO)]²⁻, acts as a counterion. It is intriguing that in complex 2 no cyano bridges are present with two water molecules coordinated to the Mn(II) ion considering that usually the cyano nitrogen atoms are strong donors and could readily replace the coordinating solvent water molecules. Abundant hydrogen bond interactions and π–π stacking between the phen rings in two complexes lead to three-dimensional supramolecular networks.