Synthesis and crystallographic characterization of a six coordinate Cu(II) complex based on hexamethylenetetramine ligand

The title compound, Cu(H₂O)₆]Cl₂.2{(CH₂)₆N₄}.4H₂O ( 1 ), has been prepared under mild hydrothermal conditions. Each Cu^II atom, located on a centre of symmetry, is coordinated by six water molecules in distorted octahedral coordination geometry. The hexamethylenetetramine molecule does not coordinate to the Cu atom but links with the Cu complex via three O—H…N hydrogen bonds. The remaining N atom of the hexamethylenetetramine is hydrogen‐bonded to the solvent water molecule. In the crystal structure, intermolecular O—H…O, O—H…N and O—H…Cl hydrogen bonds link the components into a three‐dimensional network. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal Structure and Phase Transition of Diglycine Perchlorate

Abstract  

Diglycine perchlorate (DGPCl), a new 2:1 adduct formed between glycine and perchloric acid has been obtained and studied using differential scanning calorimetry and single crystal X-ray diffraction. DGPCl undergoes a reversible first-order phase transition at 261.5 K. The crystal structures at 150 and 293 K have been determined to be triclinic, space group P‐1, Z = 2, suggesting the first-order phase transition to be an isostructural phase transition. The DGPCl crystal consists of five glycinium-monoprotonated glycinium dimers and five perchlorate anions in an asymmetric unit. The glycine moieties in the glycinium-monoprotonated glycinium dimers are non-planar. Two types of hydrogen bonds are present in the crystal, strong O–H···O hydrogen bonds and a weak N–H···O hydrogen bonds. The short, strong O–H···O hydrogen bond connects the glycinium ion and mono protonated glycinium ion. In four of the dimers, the O–H and H···O bond lengths are different, indicating the hydrogen atom to be located more close to the monoprotonated glycinium ion. However, in one of the glycinium-monoprotonated glycinium dimer the O··H and H··O bond lengths are nearly equal, suggesting the hydrogen atom (O···H···O) to be attached to the oxygen atoms of both glycine moieties. On thermal transition some of these hydrogen bonds are weakened and in all dimers the hydrogen atom seems to be located more close to the mono protonated glycinium ion.     

Synthesis,Crystal Structure and Spectroscopic Studies of 2-{(<Emphasis Type="Italic">E</Emphasis>)-[2-Hydroxyphenyl)imino]methyl} Phenol Schiff Base Molecule

Abstract  A new Schiff-base complex 2-{(E)-[2-hydroxyphenyl)imino]methyl}phenol has been synthesized and characterized by elemental analyses, UV–VIS and IR spectroscopy and single crystal X-ray determination. The structure comprises two independent and similar molecules. The two independent molecules in the asymmetric unit are hydrogen bonded and have different conformations. In each molecule, C₁₃H₁₁NO₂, adopt an E configuration about the azomethine C–N double bond. The complex crystallized in the triclinic space group P-1. 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. Also hydroxy group of the molecule is the presence intermolecular O–H···O hydrogen bonds with the hydroxy group of the other molecule. Index Abstract and Figure  A new Schiff-base complex 2-{(E)-[2-hydroxyphenyl)imino]methyl}phenol has been synthesized and characterized by elemental analyses, UV–VIS and IR spectroscopy and single crystal X-ray determination. The structure comprises two independent and similar molecules. The two independent molecules in the asymmetric unit are hydrogen bonded and have different conformations. In each molecule, C13H11NO2, adopt an E configuration about the azomethine C–N double bond. The complex crystallized in the triclinic space group P-1. 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. Also hydroxy group of the molecule is the presence intermolecular O–H···O hydrogen bonds with the hydroxy group of the other molecule.      

Crystal structure of R(–)–1–Tosyl–2–methylpyrrolidine

The crystal structure of R(–)-1-tosyl-2-methylpyrrolidine has been determined by X-ray structure analysis. The compound crystallizes in the monoclinic space group P2₁ with cell parameters a = 7.858(1), b = 14.929(6), c = 11.128(1) Å, β = 105.42(1)°. The structure has been solved by direct methods and refined to R = 0.046. There are two crystallographically independent molecules A and B in the asymmetric unit. The pyrrolidine ring of molecule A is disordered with atom C4 occupying two possible sites. The S atom has a distorted tetrahedral coordination in both the molecules. Two bifurcated hydrogen bonds are observed. Molecules are held together by hydrogen bonds.     

Crystal structure of cis‐dichloro(2,2′‐dipyridylamine)‐platinum(II)

Dichloro(2,2′‐dipyridylamine)platinum(II) has been prepared and studied by single‐crystal X‐ray diffraction methods at 293(2) K. The mononuclear complex has a square‐planar geometry. The platinum atom is coordinated by two chloride and two nitrogen atom of pyridyl groups in a cis fashion. The NH group is not coordinated, but involves in intermolecular hydrogen bonding interaction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Pulsed neutron single crystal study of the structure of 3-deazauracil

The structures of the substituted nucleic acid base 3-deazauracil, elucidated from pulsed neutron single crystal diffraction, is presented. The improved definition of the hydrogen atom positions and the hydrogen bonding scheme are emphasized in this work.     

CVD金刚石薄膜亚表面层氢杂质对表面活化反应的影响

采用密度泛函理论平面波赝势法研究了氢杂质位于氢终止金刚石薄膜亚表面层中三种不同位点处时金刚石的结构变化,以及氢原子在三种金刚石薄膜表面上的吸附难易程度,并对表面活化反应进行了过渡态搜索以探究化学气相沉积(CVD)过程中金刚石薄膜亚表面层氢杂质对表面活化的影响.对比计算结果发现:生长过程中,亚表面层的氢杂质使其附近的金刚...     

FT-IR and Raman Spectra of Ammonium Hydrogen Tartrate and Potassium Hydrogen Tartrate Crystals

FT-IR and Raman spectra of ammonium hydrogen tartrate [NH₄HC₄H₄O₆] and potassium hydrogen tartrate [KHC₄H₄O₆] have been measured. Vibrational assignments have been made for both the internal and external vibrations. Because of the free rotation of the NH₄⁺ ion, it forms only weak hydrogen bonds with the oxygen atom.     

Crystal Structure of t‐boc‐O‐benzyl‐L‐tyrosyl‐D‐alanyl‐L‐(O‐benzyl)‐glutamate : monohydrate

The crystal structure of a tripeptide, t‐boc‐O‐benzyl‐L‐tyrosyl‐D‐alanyl‐L‐(O‐benzyl)‐glutamate has been determined by direct methods, and refined by full‐matrix least squares procedures to a final R‐index of 0.060. The peptide conformation corresponds to a reverse turn — Type II , stabilized by a 4 — 1 N‐H...O hydrogen bond, with the amide proton also forming a bifurcated hydrogen bond to an oxygen atom from the C‐terminus of a neighbouring molecule.     

Trifluoromethyl group disorder in crystalline 2,8-bis(trifluoromethyl)-4-hydroxymethylquinoline

The title compound crystallized in space groupPna2₁ with lattice constantsa=13.406(1),b=18.799 (4), andc=4.785(1). The molecule is essentially flat with only fluorine atoms, methylene hydrogen atoms, and the hydroxyl hydrogen atom out of the plane of the quinoline ring. Only one of the trifluoromethyl groups of the title compound is disordered following a pattern observed in other crystal structures. Quantum chemical calculations at the AM1 level are consistent with this phenomenon. Although the carbon atom of the fixed trifluoromethyl group is further from the quinoline nitrogen atom than the carbon atom of the disordered trifluoromethyl group, the fluorine atoms of the fixed trifluoromethyl group more closely approach the quinoline nitrogen atom by 0.3 Å if the C(8)–C(10) bond in the crystal structure is freely rotated.National Research Council Associate     

Transition from amorphous semiconductor to amorphous insulator in hydrogenated carbon–germanium films investigated by IR spectroscopy

Thin a-Ge_XC_1?X:H plasma polymerized films, depending on deposition conditions, can be produced in two very different structures, namely amorphous semiconductor and amorphous insulator. The transition from amorphous insulator to amorphous semiconductor is related to the formation of germanium nanoclusters due to ions bombarding the surface of the growing material. This paper concentrates on investigations of the transition by means of IR spectroscopy. To this end a quantitative analysis of IR spectra obtained for thin films deposited on silicon substrate has been described and used for estimation of hydrogen atom concentration and bonding in the investigated material. It was found that the probability that a given H atom is bonded to a germanium or to a carbon atom is almost the same. This conclusion is true both for a-S and a-I films. The average concentration of hydrogen in the investigated material was found to be about 2.4–3.4 × 10²² cm^?2 which means that there are two times more atoms of the carbon family than hydrogen atoms in the film structure.     

Local Hydrogen Vibrational Modes in GaAs doped with Chalcogenides

Infrared absorption on GaAs doped with Chalcogenides under hydrogen plasma treatment has shown the presence of two new localised modes, namely stretching and wagging modes. We present a simple nine atom molecular model to compute these defect modes by assuming the hydrogen to be bound in the antibonding position of the nearest Ga atom, resulting in a defect complex of C_3V symmetry. Group theoretical methods are employed to obtain the frequencies of the normal modes enabling precise identification of localised modes.     

Crystal and molecular structure of (2–3-η-2-Butyne-1,4-diol)-bis-(triphenylphosphan)-nickel(O) Ni{[(C6H5)3P]2 (C4H6O2)}

The crystal and molecular structure of (2–3-η-2-Butyne-1,4-diol)-bis-(triphenylphosphan)-nickel(O) has been determined by X-ray structure analysis. It crystallizes in the tetragonal space group 14 with the cell parameters a = b = 22.277(3), and c = 15.118 (4) Å. The structure was solved by the heavy atom method and refined to R = 0.0716. The coordination geometry about the nickel atom is trigonal-planar. Each molecule is hydrogen bonded to two neighbours. The result is an eight-membered oxygen ring.     

Crystal structures of nitrato-4-bromo-2-[(2-hydroxyethylimino)methyl]phenolatoimidazolecopper and nitrato-4-chloro-2-[(2-Hydroxyethylimino)methyl]phenolatoimidazolecopper

Nitrato-4-bromo-2-[(2-hydroxyethylimino)methyl]phenolatoimidazolecopper and nitrato-4-chloro-2-[(2-hydroxyethylimino)methyl]phenolatoimidazolecopper were synthesized and studied by X-ray diffraction. The crystals are isostructural. The coordination polyhedron of the copper atom can be described as a distorted square pyramid whose basal plane is formed by the phenolic and alcoholic oxygen atoms and the nitrogen atom of the monodeprotonated tridentate azomethine molecule and the imidazole nitrogen atom. The apex of the copper polyhedron is occupied by the oxygen atom of the nitrato group. The complexes are linked together by hydrogen bonds with the participation of the nitrato groups to form a three-dimensional framework.     

In原子替位位置对新型正交GaN影响的第一性原理研究

铟(In)原子替位位置对开发新型正交GaN的储氢材料具有重要意义。当前关于In原子替位位置对正交GaN材料的影响研究相对薄弱。本文基于第一性原理研究了不同In原子替位位置下InGaN材料的形成能、电子结构、弹性特性和力学稳定性。结果表明,通常情况下间隔三个原子的In原子替位位置的形成能最小且该体系最易形成。在相同的掺杂情况下,该结构的InGaN材料也具有较大的带隙宽度以及较小的弹性模量、体积模量、剪切模量与弹性模量,这意味着其抗压能力、抗剪切应力的能力较弱,韧性以及硬度较低。此外,声子谱计算结果表明,间隔三个原子的InGaN材料在环境压力下也具有良好的力学稳定性。本研究为正交GaN的新型储氢超材料的研究提供了理论依据。     

Charge state and hydrogen diffusion in Ti-based alloys

The electronic structure, charge state, and hydrogen diffusion in icosahedral Ti-based alloys have been investigated by the methods based on the density-functional theory. The charge state of the hydrogen atom in Ti₃₆Zr₃₂Ni₁₃ has been determined for different types of tetrahedral voids. The charge state of hydrogen atoms in Ti₃₆Zr₃₂Ni₁₃, Ti₃₆Hf₃₂Ni₁₃, and Ti₄₈Zr₈Fe₁₈ is calculated for the ratio H/M = 1.7, where H is the number of hydrogen atoms and M is the number of metal atoms. It is established that hydrogen atoms in all objects studied are in an almost neutral state. The hydrogen diffusion coefficient is determined for Ti₃₆Zr₃₂Ni₁₃.     

Molecular and crystal structures of the products of crystallization of (N′-furfurylidene)isonicotinoylhydrazide from aqueous solutions of hydrochloric and acetic acids

Crystals of (N′-furfurylidene)isonicotinoylhydrazide (I), which have been isolated from a water-methanol solution of hydrochloric acid (Ia) and an aqueous solution (～50%) of acetic acid (Ib), are studied by X-ray diffraction. In Ia, the nitrogen atom of the pyridine ring is protonated. In the crystal, the intermolecular C=O?HN(Py) hydrogen bonds link the I · H⁺ cations into chains which are bound through centrosymmetric NH?W?Cl^??W′?H′N′ bridges. In molecule Ib, no protonation occurs; however, its pyridine N atom is blocked by the hydroxyl H atom of a solvate molecule of acetic acid. Crystals Ib have a layered structure. The crystallization water molecule is involved in the formation of three intermolecular hydrogen bonds, namely, those with the H atom of the amide group and the carbonyl O atoms of molecule I and an acetic acid molecule of the neighboring layer.     

Crystal structure of 2,6-dimethylpyridinium hydrogen phthalate

A new crystal of 2,6-dimethylpyridinium hydrogen phthalate (DPMHP) has been prepared and characterized by x-ray crystallography. DPMHP crystallizes in the monoclinic space group C2/c with a = 26.105(3), b = 8.2250(10), c = 13.8750(10) Å, = 116.02(1)°, V = 2677.2(5) ų, and Z = 8. The 2,6-dimethylpyridinium (DPM) is held with the hydrogen phthalate ion (HPI) by intermolecular hydrogen bond of N-H-O. A noncentered hydrogen atom is involved in the short intramolecular hydrogen of O-O [2.398(2) Å] between the neighboring carboxylic groups. The phenyl ring of the HPI appears to be deformed in comparison with the original. The entity of HPI in itself and DMPMHP as a whole are arranged in a rumple pattern. The geometrical arrangement in the crystal structure is characterized by the formation of laminar ribbons of DPMHP.     

Molecular and crystal structure of tris-(2-hydroxyethyl)ammonium 4-chlorophenoxy acetate

Tris-(2-hydroxyethyl)ammonium 4-chlorophenoxy acetate has been synthesized and characterized by ¹H NMR spectra. The molecular structure of this compound has been established by single-crystal X-ray diffractometry (a = 7.5298(23) ?, b = 22.8112(46) ?, c = 10.0921(16) ?, ?? = 111.42(2)°, V = 1613.7(7) ?³, sp. gr. P2₁/c, d _calcd = 1.382 g/cm³). In a cation, the hydrogen atom, in the presence of a nitrogen atom, forms three intramolecular hydrogen bonds with the O atoms of hydroxyl groups [2.29(3)?C2.31(3) ?]. At the same time, all three cation hydroxyl groups are involved in the formation of three intermolecular H bonds with oxygen atoms of the carboxyl anion group [H-O = 1.81(5)?2.06(4) ?].     

Crystal and Molecular Structure of Bis{2,6‐bis(hydroxymethyl)pyridine‐O,O,N}{μ‐bis(2‐hydroxymethylpyridyl)methanolate‐O,N}dicopper(II)di(propionate). First example of non‐coordinate propionate anoins

Bis{2,6‐bis (hydroxymethyl) pyridine‐O,O,N} {μ‐bis(2‐hydroxymethylpyridyl) methanolate‐O,N} dicopper(II) di(propionate) (CCDC 143763) has been prepared and studied by single‐crystal X‐ray diffraction methods at 293(2) K. The crystal structure consists of dimeric complex cation, [Cu₂(μ‐bhmp)₂(bhmpH)₂]⁺² and propionate anions (bhmp ‐ 2,6‐bis(hydroxymethyl) pyridine; bhmpH ‐ 2‐(6‐hydroxymethylpyridyl) methanolate ) and propionate anions. The complex cation contains two neutral and two monodeprotonated bhmp molecules, each coordinate to one Cu(II) atom in a tridentate chelating manner, via two O atoms and N atom. The monodeprotonated bmph molecules are also tridentate coordinate via N atom and only one O atom, which serve as bridge between two CuO₄N₂ moieties. The propionate anions are “ fixed” to the complex by the hydrogen bonds.