1H-1,2,3-triazole,a promising precursor for chemical vapor deposition of hydrogenated carbon nitride

Well-crystallized hydrogenated carbon nitride thin films have been prepared by microwave plasma enhanced chemical vapor deposition (MWPECVD). 1H-1,2,3-triazole+N₂ and Si (1 0 0) were used as precursor and substrate, respectively. Substrate temperature during the deposition was recorded to be 850 °C. The synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photo-electron spectroscopy (XPS) analyses. The plasma compositions were checked by optical emission spectroscopy (OES). XRD observation strongly suggests that the films contain polycrystalline carbon nitride with graphitic structure of (1 0 0), (0 0 2), (2 0 0) and (0 0 4). XPS peak quantification reveals that the atomic ratio of the materials C:N:O:Si is 32:41:18:9. X-ray photo-electron peak deconvolution shows that the most dominant peak of C (1s) and N (1s) narrow scans correspond to sp² hybrid structure of C₃N₄. These observations indicate that 1H-1,2,3-triazole favors the formation of hydrogenated carbon nitride with graphitic phase by CVD method and thus is in good agreement with XRD results. SEM of surface and OES of plasma also support the formation of polycrystalline carbon nitride films from 1H-1,2,3-triazole+N₂ by CVD.     

Kinetically controlled synthesis of hollow Cu2O nanocubes under solvothermal condition

Hollow Cu₂O nanocubes have been fabricated under solvothermal condition using N,N ‐dimethylformamide (DMF) as solvent at 120 °C for 12 h. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray powder diffraction (XRD) and high‐resolution transmission electron microscopy (HRTEM). Series of experiment confirmed that the amount of water, the reaction time and temperature played important roles in the morphology evolution of hollow Cu₂O nanocubes. DMF is a relatively weak alkali solvent and could release a certain amount of OH^– under the given conditions. As the release speed of OH^– from DMF became substantially slow, the nucleation and growth of Cu₂O nanocubes turned into kinetically controlled process. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

High-resolution imaging of 1:1 [0 0 0 1] ordered a-plane Al0.3Ga0.7N

We report the observation of ordering in Al_0.3Ga_0.7N as part of an epitaxial lateral overgrowth (ELO) of GaN carried out using (1 1 2¯ 2) GaN templates grown by metal-organic chemical vapor deposition on m-plane sapphire. Transmission electron microscopy showed that the crystalline quality of the ELO GaN was greatly improved when the ELO SiO₂ mask was patterned along the [1 1 2¯ 0]_sapphire direction. The ELO GaN wings had an inclined columnar shape with smooth (0 0 0 1) and (1 1 2¯ 0) facets. Layers of 1:1 [0 0 0 1] ordered a-plane Al_0.3Ga_0.7N were observed on the a-plane GaN facets by high-resolution transmission electron microscopy and high-angle annular-dark-field scanning transmission electron microscopy. However, no ordering was observed for c-plane Al_0.3Ga_0.7N layers grown at the same time on the c-plane GaN facets.     

Crystal structure and EPR spectrum of dimeric di-μ-azide-bis[cyanide(N,N-diethylethylenediamine)]-copper(II), [Cu(N3)(NCO)(diEten)]2

The title compound, [Cu(N₃)(NCO)(C₆H₁₆N₂)]₂, crystallizes in the space groupP2₁/n, witha=8.336(1),b=17.405(3),c=8.376(1) Å, β=109.73(2)^o andZ=4. The molecules are arranged as centrosymmetric dimers in which two azide ligands bridge neighboring copper ions in an asymmetric head-on fashion. The Cu(II) ion is coordinated to five nitrogen atoms which form a distorted tetragonal pyramid. At the pyramid base are the two N atoms of a diEten molecule [Cu−N=2.00(1), 2.130(9) Å], an azide end atom [Cu−N=1.99(1) Å] and a NCO group [Cu−N=1.93(1) Å]. At the pyramid apex is the other, inversion related, azide N atom in the dimer [Cu−N=2.38(1) Å]. This Cu−N contact links the monomers within a dimer. Neighboring dimers are coupled by weak N−H…O contacts. Single crystal EPR data at X-band show that the pair of resonances expected for neighboring, magnetically nonequivalents dimers, collapse into a single line, a signature of inter-dimers superexchange coupling. The observed crystal gyromagnetic tensor is used to disclose the electronic and magnetic structure around Cu(II) ions.     

Structure of the [5S,15S] isomer of the macrocyclic complex, [La(NCS)3(C24H30N6)]

The crystal and molecular structure of the [5S,15S] isomer of the [LaL(NCS)₃] complex (L=C₂₆H₃₀N₆) was determined by single crystal X-ray diffraction analysis. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ witha=13.647(4),b=19.504(4),c=11.606(4)Å. The 9-coordinate La(III) is bound to the N atoms of three monodentate isothiocyanates and to the six N atoms of the macrocycle ligand L, which has an 18-membered, six-nitrogen donor cavity and two peripheral –CH₃ substituents.     

Crystal and molecular structure of 3,5-bis(N,N-diethylimonium)-1,2,4-trithiolane-tetraiododi-μ-iododiinercurate(II)

The crystal and molecular structure of 3,5-bis(N,N-diethylimonium)-1,2,4-trithiolane-tetraiododi--iododimercurate(II), (S₃C₂N₂(C₂H₅)₄)Hg₂I₆, has been determined from a single-crystal X-ray diffraction study. The monoclinic unit cell, space groupP2₁/c, witha = 12·574(3),b = 15·777(4),c = 14·560(4) Å, and = 90·83(4) °, contains four formula-units. Three-dimensional intensity data were collected on an automatic diffractometer. Atomic parameters were refined by full-matrix least-squares methods to a conventionalR value of 0·05 for 1380 independent non-zero reflexions. The structure consists of (3,5-bis(N,N-diethyl-imonium)-1,2,4-trithiolane)²⁺ and Hg₂I ₆ ^2– ions. The cation contains a five-membered ring, S-S-C-S-C, which can be formed by oxidation of dithiocarbamato and thiuramdisulfide complexes.     

Evaluation and investigation on the effect of ionic liquid onto PMMA-PVC gel polymer blend electrolytes

1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl imide), BmImTFSI based poly(methyl methacrylate)-poly (vinyl chloride), PMMA-PVC gel polymer electrolytes were prepared by solution casting technique. These ionic liquid-based gel polymer electrolytes exhibit Arrhenius type temperature dependence of ionic conductivity. The highest ionic conductivity of (8.08 ± 0.01) × 10^− 4 Scm⁻¹ was achieved at 80 °C upon addition of 60 wt.% of BmImTFSI. X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies revealed the amorphous nature and morphology of these polymer electrolytes, respectively. The lower coherence length of the peak inferred the higher amorphous degree in these polymer matrices. Decreases in T_g and T_m indicate the flexibility of polymer backbone. The amorphous behavior of these ionic liquid-based gel polymer electrolytes are also enhanced as shown in differential scanning calorimetry (DSC) analysis. On the contrary, thermogravimetric analysis (TGA) divulges that the thermal stability of polymer electrolytes has been improved upon impregnation of BmImTFSI.     

The synthesis and crystal structure of 2-[4(S)-4,5-dihydro-4-phenyl-2-oxazolinyl]-benzenamine, and 2-[4(S)-4,5-dihydro-4-benzyl-2-oxazolinyl]-benzenamine

Two oxazolines compound 1a and 1b, 2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl-benzenamine, and (C₁₅H₁₄N₂O), 2-[4(S)-4,5-dihydro-4-benzyl-2-ozazolinyl-benzenamine (C₁₆H₁₆N₂O) were obtained in moderate yield from the reactions of 2-aminobenzonitrile with optically active L-(+)-Phenylglycinol and L-(+)-Phenylalaninol, respectively, in chlorobenzene under dry, anaerobic conditions. ZnCl₂ was dried under vacuum and acted as a Lewis acid catalyst in this reaction. The structures of 1a and 1b were determined by X-ray diffraction and NMR. There exist intra- and intermolecular N-H…N hydrogen bonds in the crystal structure.     

Crystal and molecular structure of 4-(N,N-dimethylamino) benzaldehyde thiosemicarbazone

4-(N,N-Dimethylamino)benzaldehyde thiosemicarbazone, C₁₀H₁₄N₄S, has been prepared. The crystal structure has been determined from X-ray diffractometer data byMultan 78. The crystals are triclinic:P¯1,a=8.532(1),b=9.391(1),c=15.592(4) Å,=73.81(2),=79.59(2), =82.85(2)°,Z=4, finalR=0.033 for 2198 observed reflections. Atomic charge densities have been calculated by the CNDO/2 method. The S and hydrazinic N atoms in both molecules in the asymmetric unit are in thetrans configuration. The crystal structure is stabilized by N-HS hydrogen bonds. The net negative charge on the hydrazinic N atom, calculated by the CNDO/2 method, is decreased as compared to those in some 4-phenylthiosemicarbazide derivatives.     

Crystallographic studies of dihalogeno-tetramethylethylenediamine complexes of zinc,cadmium and mercury. I: crystal and molecular structure of dichloro-(N,N,N′,N′-tetramethylethylenediamine)zinc(II)

The crystal structure of dichloro-(N,N,N,N-tetramethylethylenediamine)zinc(II), C₆H₁₆Cl₂N₂Zn, has been determined from 1684 reflexions measured on a Siemens four-circle diffractometer (A.E.D.) using the /2-scan technique and CuK radiation. The crystals are monoclinic, space groupP2₁/c,a = 7·716(3),b = 13·335(9),c =11·545(5) Å, = 105·59(6) ° andZ = 4. The structure was solved by Fourier methods, and refined by full-matrix least squares to a finalR (conventional) of 6·7 %. Anisotropic thermal parameters were evaluated for the non-hydrogen atoms, but the hydrogen atoms were assigned the equivalent isotropic thermal parameters of the carbon atoms to which they were bonded. The geometry around the zinc atom is distorted tetrahedral, with the Zn-Cl and Zn-N average bond lengths of 2·207(4) and 2·08(1) Å respectively.     

1H,4H-1,4-Diphenylpyridazino[1,2-α]pyridazine-6, 9-dione

Crystals of C₂₀H₁₆N₂O₂ are orthorombic:P2₁2₁2₁,a = 28.1364(21),b = 7.6474(2),c = 7.5376(2) Å,Z = 4, = 6.4 cm^–1 (CuK radiation), andM = 316.36. The structure has been solved by direct methods and refined by two-block least-squares toR = R _w = 0.042. The conformation of ringB is a distorted envelope at N(10), and the phenyl rings have acis configuration with respect to the pyridazine ring. Thermal motion of the molecule has been analyzed in terms of the rigid-body TLS model.On leave from Departamento de Fisica, Facultad de Ciencias Exactas, U.N.L.P., calle 115 esq. 49, La Plata, Buenos Aires, Argentina.     

Crystal structure and physical characterization of neotame methanol solvate

The crystal structure of the methanol solvate (empirical formula: 2C₂₀H₃₀N₂O₅·3CH₃OH) of a new dipeptide sweetener, neotame (N-(3,3-dimethylbutyl)-L--aspartyl-L-phenylalanine 1-methyl ester), has been determined. Crystal data: a = 9.8989(1), b = 18.1331(1), c = 27.5725(1) Å, orthorhombic, space group P2₁2₁2₁, with Z = 4. Each unit cell includes 8 neotame and 12 methanol molecules. Disorder exists in one neotame molecule and one methanol molecule. The crystals were characterized by the following techniques: hot-stage microscopy (HSM), Karl-Fischer titrimetry (KFT), powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), ¹³C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Under HSM at a heating rate of 10°C/min in silicone oil, the sample melts at 64–84°C and liberates bubbles at 71–86°C. DSC in open pans shows two overlapping endotherms at 56 and 71°C, probably due to melting and desolvation, respectively. TGA in open pans shows 5.9% weight loss due to desolvation below 70°C. Under house vacuum (23 mm Hg) over phosphorus pentoxide at 23°C, the methanol solvate produces pure amorphous anhydrate, which converts to crystalline neotame monohydrate in the presence of moisture.     

Crystal structure analyses of divalent metal cation complexes with neutral noncyclic ionophores. II. Mg2+ and Ca2+ complexes ofN,N,N′N′-tetracyclohexyl-3-oxapentanediamide

The crystal structures of the Mg(NCS)₂ and Ca(NCS)₂ complexes withN,N,NN-tetracyclohexyl-3-oxapentanediamide are discussed: (1) (C₂₈H₄₈ O₃N₂)₂·Mg(NCS)₂,M _r =1061.9, monoclinic, space groupP2₁/n,a=14.048(4),b=24.672(7),c=19.481(6) Å,=78.79(2)°,V=6623.1 ų,Z=4,d _m =1.09,d _x =1.06g cm^–3,R=0.164 for 2350 unique diffractometer data; (2) (C₂₈H₄₈O₃N₂)₃·Ca(NCS)₂,M _r =1538.4, monoclinic, space groupP2₁ (No. 4),a=14.470(3),b=19.334(5),c=17.082(4) Å,=103.72(1)°,V=4642.6ų,Z=2,d _m =1.11,d _x =1.10g cm^–3,R=0.059 for 4596 unique diffractometer data. Compound (1) is an octahedral Mg²⁺complex in which three O atoms of one ligand molecule and the two carbonyl O atoms of the other together with the N atom of a thiocyanate ion occupy the coordination sites. In complex (2) the Ca²⁺ions are nine-coordinated by the O atoms of three ligand molecules.     

Preparation and magnetic properties of CoWO4 nanocrystals

Cobalt tungstate (CoWO₄) nanocrystals with an average size of 20–50 nm were synthesized via a template‐ or surfactant‐free hydrothermal route. The crystal structure and morphology of the as‐synthesized CoWO₄ sample were characterized by X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. Magnetic measurements on the as‐synthesized CoWO₄ nanocrystals indicate a Néel temperature (T_N) of ∼40 K. This lower T_N may be a result of the nanostructured particles that reduce the exchange coupling. The new synthetic route presented in this paper has potential applications to fabricate other metal tungstates (MWO₄) materials.     

Zr‐doped CeO2 Hollow slightly‐truncated nano‐octahedrons: One‐pot synthesis,characterization and their application in catalysis of CO oxidation

Zirconium‐doped ceria hollow slightly‐truncated nano‐octahedrons (HTNOs) (Ce_1‐xZr_xO₂) were synthesized by a one‐pot, facile hydrothermal method. The morphology and crystalline structure were characterized with powder X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and the high resolution transmission electron microscopy (HRTEM). The composition and chemical valence on the surface of the as‐prepared Ce_1‐xZr_xO₂ powders were detected by X‐ray photoelectron spectroscopy (XPS) and energy dispersive spectrometry (EDS). The surface area and pore size distribution of as‐obtained Zr‐doped ceria HTNOs were measured by N₂ adsorption‐desorption measurement. Mechanisms for the growth of Zr‐doped ceria HTNOs are proposed as both oriented attachment and Ostwald ripening process and the formation of the hollow structure is strongly dependent on the addition of Zr⁴⁺ ions. Furthermore, the as‐obtained Zr‐doped ceria HTNOs revealed superior catalytic activity and thermal stability toward CO oxidation compared to pure ceria. It may provide a new path for the fabrication of inorganic hollow structures on introducing alien metal ions.     

Crystal structures of 2-pyrazinecarboxylato silver(I) and ammine 2,3-pyrazinecarboxylato disilver(I)

X-ray analysis has shown that the complexes of silver(I) with the anionic forms of 2-pyrazinecarboxylic and 2,3-pyrazinedicarboxylic acids are three-dimensional network polymers. Ag(C₅H₃O₂N₂) (1) crystallizes in space groupPna2₁ witha=7.028(2),b=11.510(3),c=6.949(2) Å andZ=4. Silver tetrahedral coordination occurs through three ligands: the first one acts as a bidentate chelator (Ag–O=2.539(4), Ag–N=2.334(4)Å), the second one involves one N pyrazine atom (Ag–N=2.196(4)Å) and the third one bonds through one O-carboxylato atom (Ag–O=2.323(4)Å). The dinuclear complex Ag₂(C₆H₂O₄N₂)(NH₃) (2) crystallizes in space groupP2₁/c witha=7.775(2),b=16.455(2),c=7.174(1) Å, -115.21(1)° andZ =4. Each of the two silver atoms shows a trigonal environment. The first silver atom involves two O carboxylic atoms (Ag–O=2.312(4), 2.374(4)Å) and one N pyrazine atom (Ag–N=2.277(3)Å) belonging to three different ligands. The second one involves one O carboxylic atom (Ag–O=2.364(3)Å) and one N pyrazine atom (Ag–N=2.304(4)Å) from the same chelating ligand and one N ammine atom (Ag–N=2.158(5)Å).     

Crystal and molecular structure of glycinehydroxamic acid

Glycinehydroxamic acid, C₂H₆N₂O₂ (NH₂CH₂C(O)NHOH), was synthesized and its crystal and molecular structure determined by single-crystal X-ray diffraction methods. The crystals are monoclinic:P2 ₁/c C _2h ⁵ , No. 14),a=5.682(2),b=7.133(2),c=9.540(3) Å,=104.38(4)°,Z=4. The structure has been solved by direct phase determination methods, and refined to anR value of 0.042 for 633 nonzero independent amplitudes. The molecule of the title compound exists in the structure as a zwitterion, NH ₃ ⁺ -CH₂-C(O)-N-OH. The hydroxamate group is planar and the N (amino) atom, from the glycine part of the molecule, deviates by 1.43 Å from the best molecular plane defined by O(1), N(1), C(1), and O(2) atoms, respectively.The molecules are held together by a network of N⁺-HO, N⁺-H¯N, and O-HO hydrogen bonds.     

Evolution of crystal structure of Zn:N films under high temperature

Zinc‐nitrogen (Zn:N) compound thin film was prepared from a pure metallic Zn target by rf magnetron sputtering at ambient temperature under the mixture of nitrogen and argon gases with the ratio of 1:1. High temperature x‐ray diffraction (HTXRD) measurement under vacuum was used to examine the evolution of structural properties of the Zn:N film. At ambient temperature, the (002), (100), and (101) planes corresponding to Zn structure were observed while at higher temperature, the left shifts corresponding to the increase of lattice constants a and c of Zn were observed. At temperatures of 320 °C, 481 °C and 554 °C, the (222), (321) and (400) planes corresponding to Zn₃N₂ structure were observed with the decrease in the intensity amplitudes of the peaks belonging to the Zn structure. The results indicate the gradual transformation of the Zn₃N₂ phase in the Zn:N films at temperature greater than 320 °C. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,conversion and comparison of the photocatalytic and electrochemical properties of ZnSe·N2H4 and ZnSe microrods

Novel ZnSe·N₂H₄ complex microrods with ∼2 μm in length and 100∼200 nm in diameter were successfully prepared by the solvothermal method at 110°C for 10 h, employing ZnAc₂·2H₂O and Se powders as the reactants, N₂H₄·H₂O as the reductant and medium. Experiments showed that the as‐obtained complex could be further converted into pure hexagonal ZnSe in an ethanol medium at 180 °C for 10 h, and the morphology hardly changed. The as‐prepared products were characterized by X‐ray powder diffraction (XRD), Energy dispersive spectrum (EDS), IR spectrum, Thermogravimetric (TG) analysis and Field emission scanning electron microscopy (SEM). Also, their photocatalytic degradation and electrochemical property were compared. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and X-ray structure analysis of a new binuclear Schiff base Co(II) complex with the ligand <Emphasis Type="Italic">N,N</Emphasis>′-bis(3-methoxysalicylidene)-1,4-butanediamine

The title binuclear complex, tris[N,N-bis(3-methoxysalicylidene)-1,4-diaminobutane] dicobalt(II), C₆₀H₇₀Co₂N₆O₁₅, was prepared by the reaction of the tetradentate Schiff base ligand bis(3-methoxysalicylidene)-1,4-diaminobutane and Co(CH₃COO)₂ · 4H₂O in a ethanol solution and structurally characterized by single-crystal X-ray diffraction. This complex has a dinuclear structure where two Co(II) ions are bridged by one N ^∘,N′-bis(3-methoxysalicylidene)-1,4-diaminobutane. The two Co(II) ions, have two distorted octahedral coordination involving two O and two N atoms.