Symmetry and structure of N-O shallow donor complexes in silicon

International Nuclear Information System (INIS)

Alt, H.Ch.; Wagner, H.E.

2012-01-01

Shallow donors in silicon related to nitrogen-oxygen complexes have been investigated by piezospectroscopy of their hydrogenic transitions in the far infrared. Complete stress dependences up to 0.25 GPa were obtained for the 1s→2p 0 and 1s→2p ± transitions of the most prominent members of the (N, O)-family, N-O-3 and N-O-5. Very unusual for shallow donors in silicon, the symmetry of the ground state wave function is T 2 -like. The lifting of orientational degeneracy for stress in the 〈1 0 0〉, 〈1 1 1〉, and 〈1 1 0〉 directions is compatible with a C 2v defect symmetry. Data from the other species of the (N, O)-family are indicative for the same symmetry. The microscopic structure of these centers, in part contradictory to present theoretical models, is discussed.

Ionic complexation of N 2O 4 by 18-crown-6

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Ricard, S.; Audet, P.; Savoie, R.

1988-08-01

An ionic complex has been obtained from N 2O 4 in the presence of the macrocyclic ether 18-crown-6. This crystalline compound has been shown from its Raman spectrum to have the formula NO +·crown·H(NO 3) 2-, with the nitrosonium ion closely associated with the crown ether rather than with the hydrogen dinitrate accompanying ion. This adduct decomposes readily in moist air to give the known complex (HNO 3·H 2O) 2·crown.

Ruthenium complexes containing 2-(2-nitrosoaryl)pyridine: structural, spectroscopic, and theoretical studies.

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Chan, Siu-Chung; Cheung, Ho-Yuen; Wong, Chun-Yuen

2011-11-21

Ruthenium complexes containing 2-(2-nitrosoaryl)pyridine (ON(^)N) and tetradentate thioether 1,4,8,11-tetrathiacyclotetradecane ([14]aneS4), [Ru(ON(^)N)([14]aneS4)](2+) [ON(^)N = 2-(2-nitrosophenyl)pyridine (2a), 10-nitrosobenzo[h]quinoline (2b), 2-(2-nitroso-4-methylphenyl)pyridine, (2c), 2-(2-nitrosophenyl)-5-(trifluoromethyl)pyridine (2d)] and analogues with the 1,4,7-trithiacyclononane ([9]aneS3)/tert-butylisocyanide ligand set, [Ru(ON(^)N)([9]aneS3)(C≡N(t)Bu)](2+) (4a and 4b), have been prepared by insertion of a nitrosonium ion (NO(+)) into the Ru-aryl bond of cyclometalated ruthenium(II) complexes. The molecular structures of the ON(^)N-ligated complexes 2a and 2b reveal that (i) the ON(^)N ligands behave as bidentate chelates via the two N atoms and the bite angles are 86.84(18)-87.83(16)° and (ii) the Ru-N(NO) and N-O distances are 1.942(5)-1.948(4) and 1.235(6)-1.244(5) Å, respectively. The Ru-N(NO) and N-O distances, together with ν(N═O), suggest that the coordinated ON(^)N ligands in this work are neutral moiety (ArNO)(0) rather than monoanionic radical (ArNO)(•-) or dianion (ArNO)(2-) species. The nitrosated complexes 2a-2d show moderately intense absorptions centered at 463-484 nm [ε(max) = (5-6) × 10(3) dm(3) mol(-1) cm(-1)] and a clearly discriminable absorption shoulder around 620 nm (ε(max) = (6-9) × 10(2) dm(3) mol(-1) cm(-1)), which tails up to 800 nm. These visible absorptions are assigned as a mixing of d(Ru) → ON(^)N metal-to-ligand charge-transfer and ON(^)N intraligand transitions on the basis of time-dependent density functional theory (TD-DFT) calculations. The first reduction couples of the nitrosated complexes range from -0.53 to -0.62 V vs Cp(2)Fe(+/0), which are 1.1-1.2 V less negative than that for [Ru(bpy)([14]aneS4)](2+) (bpy = 2,2'-bipyridine). Both electrochemical data and DFT calculations suggest that the lowest unoccupied molecular orbitals of the nitrosated complexes are ON(^)N-centered. Natural population

N2O Decomposition over Cu–Zn/γ–Al2O3 Catalysts

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Runhu Zhang

2016-12-01

Full Text Available Cu–Zn/γ–Al2O3 catalysts were prepared by the impregnation method. Catalytic activity was evaluated for N2O decomposition in a fixed bed reactor. The fresh and used catalysts were characterized by several techniques such as BET surface area, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The Cu–Zn/γ–Al2O3 catalysts exhibit high activity and stability for N2O decomposition in mixtures simulating real gas from adipic acid production, containing N2O, O2, NO, CO2, and CO. Over the Cu–Zn/γ–Al2O3 catalysts, 100% of N2O conversion was obtained at about 601 °C at a gas hourly space velocity (GHSV of 7200 h−1. Cu–Zn/γ–Al2O3 catalysts also exhibited considerably good durability, and no obvious activity loss was observed in the 100 h stability test. The Cu–Zn/γ–Al2O3 catalysts are promising for the abatement of this powerful greenhouse gas in the chemical industry, particularly in adipic acid production.

A Computational Study of Chalcogen-containing H2 X…YF and (CH3 )2 X…YF (X=O, S, Se; Y=F, Cl, H) and Pnicogen-containing H3 X'…YF and (CH3 )3 X'…YF (X'=N, P, As) Complexes.

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McDowell, Sean A C; Buckingham, A David

2018-04-20

A computational study was undertaken for the model complexes H 2 X…YF and (CH 3 ) 2 X…YF (X=O, S, Se; Y=F, Cl, H), and H 3 X'…YF and (CH 3 ) 3 X'…YF (X'=N, P, As), at the MP2/6-311++G(d,p) level of theory. For H 2 X…YF and H 3 X'…YF, noncovalent interactions dominate the binding in order of increasing YF dipole moment, except for H 3 As…F 2 , and possibly H 3 As…ClF. However, for the methyl-substituted complexes (CH 3 ) 2 X…YF and (CH 3 ) 3 X'…YF the binding is especially strong for the complexes containing F 2 , implying significant chemical bonding between the interacting molecules. The relative stability of these complexes can be rationalized by the difference in the electronegativity of the X or X' and Y atoms. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microsolvation effect and hydrogen-bonding pattern of taurine-water TA-(H2O)n (n = 1-3) complexes.

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Dai, Yumei; Wang, Yuhua; Huang, Zhengguo; Wang, Hongke; Yu, Lei

2012-01-01

The microsolvation of taurine (TA) with one, two or three water molecules was investigated by a density functional theory (DFT) approach. Quantum theory of atoms in molecules (QTAIM) analyses were employed to elucidate the hydrogen bond (H-bond) interaction characteristics in TA-(H(2)O)(n) (n = 1-3) complexes. The results showed that the intramolecular H-bond formed between the hydroxyl and the N atom of TA are retained in most TA-(H(2)O)(n) (n = 1-3) complexes, and are strengthened via cooperative effects among multiple H-bonds from n = 1-3. A trend of proton transformation exists from the hydroxyl to the N atom, which finally results in the cleavage of the origin intramolecular H-bond and the formation of a new intramolecular H-bond between the amino and the O atom of TA. Therefore, the most stable TA-(H(2)O)(3) complex becomes a zwitterionic complex rather than a neutral type. A many-body interaction analysis showed that the major contributors to the binding energies for complexes are the two-body energies, while three-body energies and relaxation energies make significant contributions to the binding energies for some complexes, whereas the four-body energies are too small to be significant.

Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium

International Nuclear Information System (INIS)

Benaud, Olivier; Berthet, Jean-Claude; Thuery, Pierre; Ephritikhine, Michel

2011-01-01

In contrast to the neutral macrocycle [UN* 2 (N,C)] (1) [N* = N(SiMe 3 ) 3 ; N,C = CH 2 SiMe 2 N-(SiMe 3 )] which was quite inert toward I 2 , the anionic bismetallacycle [NaUN*(N,C) 2 ] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me 3 Si)NSiMe 2 CH 2 CH 2 SiMe 2 N(SiMe 3 )] resulting from C-C coupling of the two CH 2 groups, and [NaUN*(N,O) 2 ] (3) [N,O = OC(=CH 2 )SiMe 2 N(SiMe 3 )], which is devoid of any U-C bond, was oxidized into the UV bismetallacycle [Na{UN*(N,O) 2 }2(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN 3 or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN* 2 (N,C)(N 3 )] [M = Na, 7a or Na(15-crown-5), 7b], M[UN* 2 (N,C)(CN)] [M = NEt 4 , 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N 3 ) 2 ] [M = Na, 9a or Na(THF)4, 9b], [NEt 4 ][UN*(N,N)(CN) 2 ] (10), M[UN*(N,O) 2 (N 3 )] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O) 2 (CN)] [M = NEt 4 , 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral UV complex [U(N{SiMe 3 }-SiMe 2 C{CHI}O) 2 I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined. (authors)

Synthesis, solvatochromism and crystal structure of trans-[Cu(Et2NCH2CH2NH2)2.H2O](NO3)2 complex: Experimental with DFT combination

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Warad, Ismail; Musameh, Sharif; Badran, Ismail; Nassar, Nashaat N.; Brandao, Paula; Tavares, Carlos Jose; Barakat, Assem

2017-11-01

In this study, two dicationic asymmetrical diamine/copper(II) nitrate salt complexes of the general formula trans-[CuII(NN‧)2.H2O](NO3)2 were successfully synthesized using N,N-dimethylethylenediamine and N,N-diethylethylenediamine as asymmetrical diamine ligands. The structure of complex 2 was identified by X-ray single crystal diffraction analysis confirming that the bidentate ligand N,N-dimethylethylenediamine forms a penta-coordinated complex with an H2O molecule located around the copper(II) ion in a trans configuration. It was found that the metal centre is coordinated in a distorted square pyramidal fashion with a τ value of 0.274. The desired complexes were fully characterized using, MS, UV-Vis, CV, FTIR, TG/DTA, and Hirshfeld surface computational analysis. High level theoretical calculations were also performed in order to investigate the complexes structure, conformers, vibrational frequencies, and their excited states.

Thermochemical characteristics of La n+1Ni nO3n+1 oxides

International Nuclear Information System (INIS)

Bannikov, D.O.; Safronov, A.P.; Cherepanov, V.A.

2006-01-01

Lanthanum nickelates: La 2 NiO 4+δ , La 3 Ni 2 O 7-δ , La 4 Ni 3 O 10-δ and LaNiO 3-δ the members of Ruddlesden-Popper series La n+1 Ni n O 3n+1 were prepared using citrate route. Dissolution enthalpies of complex oxides as well as a number of subsidiary substances were measured by means of Calvet calorimeter in 1 M solution of hydrochloric acid at 25 deg. C. The dissolution scheme of complex oxides in hydrochloric acid was proposed and enthalpies of formation of the complex oxides from binary oxides were calculated considering oxygen nonstoichiometry of these substances. Enthalpies of step-by-step oxidation were evaluated. Partial enthalpy contribution of LaO layers was calculated endothermic equals to 30.9 J/mol while partial enthalpy contribution of perovskite LaNiO 3 layers was negative equals to -97.0 J/mol. Enthalpy of formation of any complex oxide of Ruddlesden-Popper series fits very well to the linear regression based on these values

Azobenzene Pd(II) complexes with N^N- and N^O-type ligands

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Nikolaeva, M. V.; Puzyk, An. M.; Puzyk, M. V.

2017-05-01

Methods of synthesis of cyclometalated azobenzene palladium(II) complexes of [Pd(N^N)Azb]ClO4 and [Pd(N^O)Azb]ClO4 types (where Azb- is the deprotonated form of azobenzene; N^N is 2NH3, ethylenediamine, or 2,2'-bipyridine; and (N^O)- is the deprotonated form of amino acid (glycine, α-alanine, β-alanine, tyrosine, or tryptophan)) are developed. The electronic absorption and the electrochemical properties of these complexes are studied.

Preparation of YBa2Cu3O7-δ powders by the thermal decomposition of a heteronuclear complex, CuY1/3Ba2/3(dhbaen)(NO3)1/3(H2O)3

International Nuclear Information System (INIS)

Hasegawa, E.; Aono, H.; Sadaoka, Y.; Traversa, E.

1999-01-01

YBa 2 Cu 3 O 7-δ powders were prepared by the thermal decomposition of a heteronuclear complex, CuY 1/3 Ba 2/3 (dhbaen)(NO 3 ) 1/3 (H 2 O) 3 . The products of the complex thermal decomposition were analyzed by TG-DTA, XRD, SEM-Auger and XPS. The decomposition of the CuY 1/3 Ba 2/3 -complex was obtained at about 500 C and the product was a mixture of oxides and carbonates. The formation of YBa 2 Cu 3 O 7-δ proceeded at 800 C, with a gradual decomposition of the carbonates. A homogeneous distribution of each element, Y, Ba, and Cu, was observed for the decomposed CuY 1/3 Ba 2/3 -complex by SEM-Auger analysis. The binding energy values of Ba3d 5/2 and O1s photolines from Ba and O in the superconductive lattice did not shift during the sputtering period. Furthermore, the formation of Ba rich regions on the surface was depressed by using the complex as a starting material for homogeneous 123-oxide, YBa 2 Cu 3 O 7-δ . (orig.)

Synthesis, structure, luminescent, and magnetic properties of carbonato-bridged Zn(II)2Ln(III)2 complexes [(μ4-CO3)2{Zn(II)L(n)Ln(III)(NO3)}2] (Ln(III) = Gd(III), Tb(III), Dy(III); L(1) = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato, L(2) = N,N'-bis(3-ethoxy-2-oxybenzylidene)-1,3-propanediaminato).

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Ehama, Kiyomi; Ohmichi, Yusuke; Sakamoto, Soichiro; Fujinami, Takeshi; Matsumoto, Naohide; Mochida, Naotaka; Ishida, Takayuki; Sunatsuki, Yukinari; Tsuchimoto, Masanobu; Re, Nazzareno

2013-11-04

Carbonato-bridged Zn(II)2Ln(III)2 complexes [(μ4-CO3)2{Zn(II)L(n)Ln(III)(NO3)}2]·solvent were synthesized through atmospheric CO2 fixation reaction of [Zn(II)L(n)(H2O)2]·xH2O, Ln(III)(NO3)3·6H2O, and triethylamine, where Ln(III) = Gd(III), Tb(III), Dy(III); L(1) = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato, L(2) = N,N'-bis(3-ethoxy-2-oxybenzylidene)-1,3-propanediaminato. Each Zn(II)2Ln(III)2 structure possessing an inversion center can be described as two di-μ-phenoxo-bridged {Zn(II)L(n)Ln(III)(NO3)} binuclear units bridged by two carbonato CO3(2-) ions. The Zn(II) ion has square pyramidal coordination geometry with N2O2 donor atoms of L(n) and one oxygen atom of a bridging carbonato ion at the axial site. Ln(III) ion is coordinated by nine oxygen atoms consisting of four from the deprotonated Schiff-base L(n), two from a chelating nitrate, and three from two carbonate groups. The temperature-dependent magnetic susceptibilities in the range 1.9-300 K, field-dependent magnetization from 0 to 5 T at 1.9 K, and alternating current magnetic susceptibilities under the direct current bias fields of 0 and 1000 Oe were measured. The magnetic properties of the Zn(II)2Ln(III)2 complexes are analyzed on the basis of the dicarbonato-bridged binuclear Ln(III)-Ln(III) structure, as the Zn(II) ion with d(10) electronic configuration is diamagnetic. ZnGd1 (L(1)) and ZnGd2 (L(2)) show a ferromagnetic Gd(III)-Gd(III) interaction with J(Gd-Gd) = +0.042 and +0.028 cm(-1), respectively, on the basis of the Hamiltonian H = -2J(Gd-Gd)ŜGd1·ŜGd2. The magnetic data of the Zn(II)2Ln(III)2 complexes (Ln(III) = Tb(III), Dy(III)) were analyzed by a spin Hamiltonian including the crystal field effect on the Ln(III) ions and the Ln(III)-Ln(III) magnetic interaction. The Stark splitting of the ground state was so evaluated, and the energy pattern indicates a strong easy axis (Ising type) anisotropy. Luminescence spectra of Zn(II)2Tb(III)2 complexes were observed, while those

MOLECULAR COMPLEXES OF SULPHUR DIOXIDE WITH N,O-CONTAINING ORGANIC BASES (REVIEW

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R. E. Khoma

2016-10-01

Full Text Available The literature data on the synthesis, stoichiometry, structure and relative stability of molecular  complexes of sulphur dioxide with N,O-containing organic bases have been systematized and  generalized. It was shown that the yield of the reaction product of sulfur dioxide with organic  bases (such as amines are strongly influenced by the conditions of synthesis: the nature of  the solvent (basicity, polarity, the temperature and SO2:L ratio in the reaction medium. The stoichiometry of SO2*nL molecular complexes depends on ligand denticity, as well as its  ability to H-bonding. The reaction of the sulfur oxide (IV with organic bases can give S←N and S←O complexes. With the increase of the value of base proton affinity the decrease ΔrSN values has been marked. Characteristic parameter Δr SN = r SN – a1(rS+ rN (where rSNis the S←N donor-acceptor bond length has been determined by microwave spectroscopy and X-ray analysis, rSand rNwere the tabulated values of the homopolar covalent radii of sulphur and nitrogen heteroatoms. The dependence of formation enthalpy of molecular complexes of basic amines and spectral characteristics has been noted; enthalpy-entropy compensation for S←N and S←O complex-es has been stated. Despite the limited experimental data on the thermodynamics of complex formation and the lengths of donor-acceptor bonds for the same compounds it has been found bond S←N strength in SO2 molecular complexes to depend on the intrinsic value of ΔrSN. The contribution of van der Waals forces and charge transfer forces to the formation of molecular complexes of sulphur dioxide has been stated.

Crystal structure of bis-(μ-3-nitro-benzoato)-κ3O,O':O;κ3O:O,O'-bis-[bis-(3-cyano-pyridine-κN1)(3-nitro-benzoato-κ2O,O')cadmium].

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Hökelek, Tuncer; Akduran, Nurcan; Özen, Azer; Uğurlu, Güventürk; Necefoğlu, Hacali

2017-03-01

The asymmetric unit of the title compound, [Cd 2 (C 7 H 4 NO 4 ) 4 (C 6 H 4 N 2 ) 4 ], contains one Cd II atom, two 3-nitro-benzoate (NB) anions and two 3-cyano-pyridine (CPy) ligands. The two CPy ligands act as monodentate N(pyridine)-bonding ligands, while the two NB anions act as bidentate ligands through the carboxyl-ate O atoms. The centrosymmetric dinuclear complex is generated by application of inversion symmetry, whereby the Cd II atoms are bridged by the carboxyl-ate O atoms of two symmetry-related NB anions, thus completing the distorted N 2 O 5 penta-gonal-bipyramidal coordination sphere of each Cd II atom. The benzene and pyridine rings are oriented at dihedral angles of 10.02 (7) and 5.76 (9)°, respectively. In the crystal, C-H⋯N hydrogen bonds link the mol-ecules, enclosing R 2 2 (26) ring motifs, in which they are further linked via C-H⋯O hydrogen bonds, resulting in a three-dimensional network. In addition, π-π stacking inter-actions between parallel benzene rings and between parallel pyridine rings of adjacent mol-ecules [shortest centroid-to-centroid distances = 3.885 (1) and 3.712 (1) Å, respectively], as well as a weak C-H⋯π inter-action, may further stabilize the crystal structure.

Mid-infrared signatures of hydroxyl containing water clusters: Infrared laser Stark spectroscopy of OH–H{sub 2}O and OH(D{sub 2}O){sub n} (n = 1-3)

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Hernandez, Federico J. [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); INFIQC, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón, X5000HUA Córdoba (Argentina); Brice, Joseph T.; Leavitt, Christopher M.; Liang, Tao; Douberly, Gary E., E-mail: douberly@uga.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Raston, Paul L. [Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807 (United States); Pino, Gustavo A. [INFIQC, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, Pabellón, X5000HUA Córdoba (Argentina)

2015-10-28

Small water clusters containing a single hydroxyl radical are synthesized in liquid helium droplets. The OH–H{sub 2}O and OH(D{sub 2}O){sub n} clusters (n = 1-3) are probed with infrared laser spectroscopy in the vicinity of the hydroxyl radical OH stretch vibration. Experimental band origins are qualitatively consistent with ab initio calculations of the global minimum structures; however, frequency shifts from isolated OH are significantly over-predicted by both B3LYP and MP2 methods. An effective Hamiltonian that accounts for partial quenching of electronic angular momentum is used to analyze Stark spectra of the OH–H{sub 2}O and OH–D{sub 2}O binary complexes, revealing a 3.70(5) D permanent electric dipole moment. Computations of the dipole moment are in good agreement with experiment when large-amplitude vibrational averaging is taken into account. Polarization spectroscopy is employed to characterize two vibrational bands assigned to OH(D{sub 2}O){sub 2}, revealing two nearly isoenergetic cyclic isomers that differ in the orientation of the non-hydrogen-bonded deuterium atoms relative to the plane of the three oxygen atoms. The dipole moments for these clusters are determined to be approximately 2.5 and 1.8 D for “up-up” and “up-down” structures, respectively. Hydroxyl stretching bands of larger clusters containing three or more D{sub 2}O molecules are observed shifted approximately 300 cm{sup −1} to the red of the isolated OH radical. Pressure dependence studies and ab initio calculations imply the presence of multiple cyclic isomers of OH(D{sub 2}O){sub 3}.

Carbonato-bridged Ni(II)2Ln(III)2 (Ln(III) = Gd(III), Tb(III), Dy(III)) complexes generated by atmospheric CO2 fixation and their single-molecule-magnet behavior: [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(MeOH or H2O)Ln(III)(NO3)}2]·solvent [3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato].

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Sakamoto, Soichiro; Fujinami, Takeshi; Nishi, Koshiro; Matsumoto, Naohide; Mochida, Naotaka; Ishida, Takayuki; Sunatsuki, Yukinari; Re, Nazzareno

2013-06-17

Atmospheric CO2 fixation of [Ni(II)(3-MeOsaltn)(H2O)2]·2.5H2O [3-MeOsaltn = N,N'-bis(3-methoxy-2-oxybenzylidene)-1,3-propanediaminato], Ln(III)(NO3)3·6H2O, and triethylamine occurred in methanol/acetone, giving a first series of carbonato-bridged Ni(II)2Ln(III)2 complexes [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(MeOH)Ln(III)(NO3)}2] (1Gd, 1Tb, and 1Dy). When the reaction was carried out in acetonitrile/water, it gave a second series of complexes [(μ4-CO3)2{Ni(II)(3-MeOsaltn)(H2O)Ln(III)(NO3)}2]·2CH3CN·2H2O (2Gd, 2Tb, and 2Dy). For both series, each Ni(II)2Ln(III)2 structure can be described as two di-μ-phenoxo-bridged Ni(II)Ln(III) binuclear units bridged by two carbonato CO3(2-) units to form a carbonato-bridged (μ4-CO3)2{Ni(II)2Ln(III)2} structure. The high-spin Ni(II) ion has octahedral coordination geometry, and the Ln(III) ion is coordinated by O9 donor atoms from Ni(II)(3-MeOsaltn), bidentate NO3(-), and one and two oxygen atoms of two CO3(2-) ions. The NO3(-) ion for the first series roughly lie on Ln-O(methoxy) bonds and are tilted toward the outside, while for the second series, the two oxygen atoms roughly lie on one of the Ln-O(phenoxy) bonds due to the intramolecular hydrogen bond. The temperature-dependent magnetic susceptibilities indicated a ferromagnetic interaction between the Ni(II) and Ln(III) ions (Ln(III) = Gd(III), Tb(III), Dy(III)) for all of the complexes, with a distinctly different magnetic behavior between the two series in the lowest-temperature region due to the Ln(III)-Ln(III) magnetic interaction and/or different magnetic anisotropies of the Tb(III) or Dy(III) ion. Alternating-current susceptibility measurements under the 0 and 1000 Oe direct-current (dc) bias fields showed no magnetic relaxation for the Ni(II)2Gd(III)2 complexes but exhibited an out-of-phase signal for Ni(II)2Tb(III)2 and Ni(II)2Dy(III)2, indicative of slow relaxation of magnetization. The energy barriers, Δ/kB, for the spin flipping were estimated from the Arrhenius

Diaqua-2κ2O-bis(μ-1-oxido-2-naphthoato-1:2κ3O1,O2:O2′;2:3κ3O2:O1,O2′-bis(1-oxido-2-naphthoato-1κ1O2,O2;3κ2O1,O2-hexapyridine-1κ2N,2κ2N,3κ2N-trimanganese(II/III pyridine disolvate dihydrate

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Daqi Wang

2008-12-01

Full Text Available The title complex, [Mn3(C11H6O34(C5H5N6(H2O2]·2H2O·2C5H5N, is a trinuclear mixed oxidation state complex of overline1 symmetry. The three Mn atoms are six-coordinated in the shape of distorted octahedra, each coordinated with an O4N2 set of donor atoms, where the ligands exhibit mono- and bidentate modes. However, the coordination of the MnII ion located on the inversion centre involves water molecules at two coordination sites, whereas that of the two symmetry-related MnIII ions involves an O4N2 set of donor atoms orginating from the organic ligands. Intramolecular C—H...π interactions between neighbouring pyridine ligands stabilize this arrangement. A two-dimensional network parallel to (001 is formed by intermolecular O—H...O hydrogen bonds.

[(2S-2-(3,5-Dichloro-2-oxidobenzylideneamino-3-(4-hydroxyphenylpropionato-κ3O,N,O′](dimethylformamide-κOcopper(II

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Hong Liang

2008-04-01

Full Text Available In the title complex, [Cu(C16H11Cl2NO4(C3H7NO] , the CuII atom is coordinated by two O atoms and one N atom from the tridentate ligand L2− {LH2 = (2S-[2-(3,5-dichloro-2-hydroxybenzylideneimino]-3-(4-hydroxyphenylpropionic acid} and one O atom from a dimethylformamide molecule, resulting in a slightly distorted square-planar geometry. The structure forms a one-dimensional chain through weak coordination bonds [Cu...O 3.080 (1, Cu...Cl 3.269 (1 Å] and a three-dimensional network through O—H...O and C—H...O hydrogen bonds.

The rate coefficient for the reaction NO2 + NO3 yielding NO + NO2 + O2 from 273 to 313 K

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Cantrell, Chris A.; Shetter, Richard E.; Mcdaniel, Anthony H.; Calvert, Jack G.

1990-01-01

The ratio of rate constants for the reaction NO3 + NO yielding 2 NO2 (k3) and the reaction NO2 + NO3 yielding NO + NO2 + O2 (k4) were determined by measuring of NO and NO2 concentrations of NO and NO2 in an N2O5/NO2/N2 mixture over the temperature range 273-313 K. The measured ratio was found to be expressed by the equation k3/k4 = 387 exp(-1375/T). The results are consistent with those of Hammer et al. (1986).

Butane-1,4-diammonium bis(pyridine-2,6-dicarboxylato-κ3O2,N,O6cadmate(II dihydrate

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Najmeh Firoozi

2008-10-01

Full Text Available In the title compound, (C4H14N2[Cd(C7H3NO42]·2H2O, the CdII ion is coordinated by four O atoms [Cd—O = 2.2399 (17–2.2493 (17 Å] and two N atoms [Cd—N = 2.3113 (15 and 2.3917 (15 Å] from two tridentate pyridine-2,6-dicarboxylato ligands in a distorted octahedral geometry. The uncoordinated water molecules are involved in O—H...O and N—H...O hydrogen bonds, which contribute to the formation of a three-dimensional supramolecular structure, along with π–π stacking interactions [centroid–centroid distances of 3.5313 (13 and 3.6028 (11 Å between the pyridine rings of neighbouring dianions].

Structuring effects of [Ln6O(OH)8(NO3)6(H2O)12]2+ entities

International Nuclear Information System (INIS)

Guillou, O.; Daiguebonne, C.; Calvez, G.; Le Dret, F.; Car, P.-E.

2008-01-01

In order to obtain highly porous lanthanide-based coordination polymers we are currently investigating reactions between [Ln 6 O(OH) 8 (NO 3 ) 6 (H 2 O) 12 ] 2+ di-cationic hexanuclear entities and sodium salts of benzene-poly-carboxylic acids. Two new coordination polymers obtained during this study are reported here. In both cases, the hexanuclear entity has been destroyed during the reaction. However the resulting compounds are original thanks to a structuring effect of the poly-metallic complex. The first compound of chemical formula [Y 2 (C 8 H 4 O 4 ) 3 (DMF)(H 2 O)],2DMF crystallizes in the monoclinic system, space group P121/n (n o 14) with a = 16.0975(3) A, b = 14.4605(3) A, c = 17.7197(4) A, β = 92.8504(9) o and Z = 4. The second compound of chemical formula Y 2 (NO 3 ) 2 (C 10 H 2 O 8 )(DMF) 4 crystallizes in the triclinic system, space group P-1 (n o 2) with a = 7.5312(3) A, b = 9.0288(3) A, c = 13.1144(6) A, α = 92.6008(14) o , β = 94.9180(14) o , γ = 112.1824(16) o and Z = 2. Both crystal structures are 2D. Both crystal structures are described and the original structural features are highlighted and related to a potential structuring effect of the hexanuclear precursor

Crystal structures of bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III complexes containing an acetonitrile or monodentate thyminate(1− ligand

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Mika Sakate

2016-04-01

Full Text Available The crystal structures of bis[2-(pyridin-2-ylphenyl]rhodium(III complexes with the metal in an octahedral coordination containing chloride and acetonitrile ligands, namely (OC-6-42-acetonitrilechloridobis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [RhCl(C11H8N2(CH3CN] (1, thyminate(1− and methanol, namely (OC-6-42-methanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(CH3OH]·CH3OH·0.5H2O (2, and thyminate(1− and ethanol, namely (OC-6-42-ethanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(C2H5OH]·C2H5OH (3, are reported. The acetonitrile complex, 1, is isostructural with the IrIII analog. In complexes 2 and 3, the monodeprotonated thyminate (Hthym− ligand coordinates to the RhIII atom through the N atom, and the resulting Rh—N(Hthym bond lengths are relatively long [2.261 (2 and 2.252 (2 Å for 2 and 3, respectively] as compared to the Rh—N bonds in the related thyminate complexes. In each of the crystals of 2 and 3, the complexes are linked via a pair of intermolecular N—H...O hydrogen bonds between neighbouring Hthym− ligands, forming an inversion dimer. A strong intramolecular O—H...O hydrogen bond between the thyminate(1− and alcohol ligands in mutually cis positions to each other is also observed.

Two novel mixed-ligand complexes containing organosulfonate ligands.

Science.gov (United States)

Li, Mingtian; Huang, Jun; Zhou, Xuan; Fang, Hua; Ding, Liyun

2008-07-01

The structures reported herein, viz. bis(4-aminonaphthalene-1-sulfonato-kappaO)bis(4,5-diazafluoren-9-one-kappa(2)N,N')copper(II), [Cu(C(10)H(8)NO(3)S)(2)(C(11)H(6)N(2)O)(2)], (I), and poly[[[diaquacadmium(II)]-bis(mu-4-aminonaphthalene-1-sulfonato)-kappa(2)O:N;kappa(2)N:O] dihydrate], {[Cd(C(10)H(8)NO(3)S)(2)(H(2)O)(2)].2H(2)O}(n), (II), are rare examples of sulfonate-containing complexes where the anion does not fulfill a passive charge-balancing role, but takes an active part in coordination as a monodentate and/or bridging ligand. Monomeric complex (I) possesses a crystallographic inversion center at the Cu(II) atom, and the asymmetric unit contains one-half of a Cu atom, one complete 4-aminonaphthalene-1-sulfonate (ans) ligand and one 4,5-diazafluoren-9-one (DAFO) ligand. The Cu(II) atom has an elongated distorted octahedral coordination geometry formed by two O atoms from two monodentate ans ligands and by four N atoms from two DAFO molecules. Complex (II) is polymeric and its crystal structure is built up by one-dimensional chains and solvent water molecules. Here also the cation (a Cd(II) atom) lies on a crystallographic inversion center and adopts a slightly distorted octahedral geometry. Each ans anion serves as a bridging ligand linking two Cd(II) atoms into one-dimensional infinite chains along the [010] direction, with each Cd(II) center coordinated by four ans ligands via O and N atoms and by two aqua ligands. In both structures, there are significant pi-pi stacking interactions between adjacent ligands and hydrogen bonds contribute to the formation of two- and three-dimensional networks.

Comparison of N2O5 mixing ratios during NO3Comp 2007 in SAPHIR

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A. W. Rollins

2012-11-01

Full Text Available N2O5 detection in the atmosphere has been accomplished using techniques which have been developed during the last decade. Most techniques use a heated inlet to thermally decompose N2O5 to NO3, which can be detected by either cavity based absorption at 662 nm or by laser-induced fluorescence. In summer 2007, a large set of instruments, which were capable of measuring NO3 mixing ratios, were simultaneously deployed in the atmosphere simulation chamber SAPHIR in Jülich, Germany. Some of these instruments measured N2O5 mixing ratios either simultaneously or alternatively. Experiments focused on the investigation of potential interferences from, e.g., water vapour or aerosol and on the investigation of the oxidation of biogenic volatile organic compounds by NO3. The comparison of N2O5 mixing ratios shows an excellent agreement between measurements of instruments applying different techniques (3 cavity ring-down (CRDS instruments, 2 laser-induced fluorescence (LIF instruments. Datasets are highly correlated as indicated by the square of the linear correlation coefficients, R2, which values were larger than 0.96 for the entire datasets. N2O5 mixing ratios well agree within the combined accuracy of measurements. Slopes of the linear regression range between 0.87 and 1.26 and intercepts are negligible. The most critical aspect of N2O5 measurements by cavity ring-down instruments is the determination of the inlet and filter transmission efficiency. Measurements here show that the N2O5 inlet transmission efficiency can decrease in the presence of high aerosol loads, and that frequent filter/inlet changing is necessary to quantitatively sample N2O5 in some environments. The analysis of data also demonstrates that a general correction for degrading filter transmission is not applicable for all conditions encountered during this campaign. Besides the effect of a gradual degradation of the inlet transmission efficiency aerosol exposure, no other interference

Synthesis and vibrational spectra of cooper(II) and erbium(III) complexes with 2-diazo[2'-(oxymethyldiphenylphosphinyl)phenyl]-4-tert-butylphenol (HL) - [CuL2]·2H2O and Er(NO3)3·2HL·2H2O. Crystal structure of [CuL2]·2H2O

International Nuclear Information System (INIS)

Tsivadze, A.Yu.; Minacheva, L.Kh.; Ivanova, I.S.; Pyatova, E.N.; Sergienko, V.S.; Baulin, V.E.

2008-01-01

Paper describes synthesis of CuL 2 ·2H 2 O (I) complex cupric salt and of Er(NO 3 ) 3 ·2HL·2H 2 O (II) erbium nitrate complex (HL=2-diazo-[2'(oxymethyl-diphenyl-phosphinyl)phenyl]-4-tert-butylphenol). One interprets the fundamental frequencies within the IR-spectra of (I) and (II) compounds. One has performed X-ray diffraction analysis of I compound. The crystals are monoclinic ones, a=15.157(3), b=17.080(2), c=22.451(9) A, β=106.09(3) Deg, V=5584(3) A 3 , Z=4, C2/c sp.gr., R=0.0546 as to 1152 reflections with I>2σ(I). The copper atom coordination polyhedron (C 2 symmetry) may be described as a symmetrically-prolonged square bipyramid (4+2). Cu polyhedron central square is formed by substituted phenol oxygen atom and by one of diazo-group nitrogen atoms of either of two deprotonated ligands, namely: L - (Cu-N 1.969(6), Cu-O 1.899(5) A). The angles between lying opposite O and N atoms constitute 157.6 Deg, while the rest equatorial angles range within 90.6 Deg-95.9 Deg. The axial positions are occupied by O(2) and O(2A) anisole atoms (Cu-O 2.737(6) A, O(2)Cu(1)O(2A) angle constitutes 132.3 Deg). Within crystal I the complex molecules and the crystallization molecules of water are combined by by the hydrogen bond system. According to the IR-spectra data, within complex II in contrast to compound I erbium atom coordination by HL ligand involves oxygen phosphoryl atom [ru

Poly[[diaqua-μ4-pyrazine-2,3-dicarboxylato-κ6N,O2:O2′:O3,O3′:O3-strontium(II] monohydrate

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Vahid Amani

2008-07-01

Full Text Available In the title compound, {[Sr(C6H2N2O4(H2O2]·H2O}n, the SrII ions are bridged by the pyrazine-2,3-dicarboxylate ligands with the formation of two-dimensional polymeric layers parallel to the ac plane. Each SrII ion is eight-coordinated by one N and five O atoms from the four ligands and two water molecules. The coordination polyhedron is derived from a pentagonal bipyramid with an O atom at the apex on one side of the equatorial plane and two O atoms sharing the apical site on the other side. The coordinated and uncoordinated water molecules are involved in O—H...O and O—H...N hydrogen bonds, which consolidate the crystal structure.

Molecular structure and vibrational spectrum of the complex [ErL(H2O)(NO3)3] (L 1,4,10,13-tetraoxi-7,16-diaza(diphenylphosphinylmethyl) cyclooctadecane

International Nuclear Information System (INIS)

Minacheva, L.Kh.; Ivanova, I.S.; Kireeva, I.K.; Sakharova, V.G.; Tsivadze, A.Yu.; Sergienko, V.S.; Baulin, V.E.

2000-01-01

Synthesis of podandocoronand on the basis of diazo-18-crown-6 (DA18K6) 1,4,10,13-tetraoxi-7,16-diazo (diphenylphosphynylmethyl)cyclooctadecane (L) and erbium nitrate complex with L of the [ErL(H 2 O)(NO 3 ) 3 ] (I) composition is described. The IR-spectra of the free ligand L and complex I are studied and interpreted.The crystals are monoclinic: a = 10.432(2), b = 19.909(4), c = 21.361(4), β = 100.39(3) Deg, V = 4364(2) A 3 , sp. gr. P2 1 /n, Z = 4, ρ = 1.617 g/cm 3 . The structure I is formed of discrete molecular complexes. The Er atom coordination number is equal to 9. Three nitrate groups are bidentate-cyclic coordinated; two of them are in trans-position to each other; the H 2 O molecule is trans-position to the third NO 3 -group. The ligand L is coordinated by metal through two oxygen phosphoryl atoms. Thus, the Er atom coordination polyhedron may be described as octahedron, if each NO 3 -group occupies one coordination position. The Er-O(L) and Er-O(NO 3 ) overage distances are equal to 2.25 and 2.43 A correspondingly. Er-O(H 2 O) - 2.29 A. The H 2 O coordinated molecule forms intermolecular hydrogen atom and two oxygen atoms of the DA18K6 macrocycle [ru

Catalytic properties of extraframework iron-containing species in ZSM-5 for N2O decomposition

NARCIS (Netherlands)

Li, G.; Pidko, E.A.; Filot, I.A.W.; Santen, van R.A.; Li, Can; Hensen, E.J.M.

2013-01-01

The reactivity of mononuclear and binuclear iron-containing complexes in ZSM-5 zeolite for catalytic N2O decomposition has been investigated by periodic DFT calculations and microkinetic modeling. On mononuclear sites, the activation of a first N2O molecule is favorable. The rate of catalytic N2O

catena-Poly[nickel(II-bis(μ-2-aminoethanesulfonato-κ3N,O:O′;κ3O:N,O′

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Feng Yang

2010-07-01

Full Text Available In the title polymeric complex, [Ni(C2H6NO3S2]n, the NiII ion occupies a special position on an inversion centre and displays a slightly distorted octahedral coordination geometry, being linked to four sulfonate O atoms and to two N atoms of the taurine ligands. The sulfonate groups doubly bridge symmetry-related NiII centers, forming polymeric chains along the a axis.

[Ag(NH3)2]Ag(OsO3N)2: a new nitridoosmate(VIII)

International Nuclear Information System (INIS)

Wickleder, M.S.; Pley, Martin

2004-01-01

Dark brown single crystals of [Ag(NH 3 ) 2 ]Ag(OsO 3 N) 2 were obtained from the reaction of Ag 2 CO 3 , OsO 4 , and NH 3 in aqueous solution. The crystal structure was solved in the monoclinic space group C2/m, with the following unit-cell dimensions: a=1962.5(3), b=633.1(1), c=812.6(1) pm, β=96.71(1) deg. The final reliability factor was R=0.0256 for 1034 reflections with I>2σ(I). Linear [Ag(NH 3 ) 2 ] + ions are present oriented perpendicular to the [010] direction, leading to short Ag + -Ag + distances of 316 pm. A second type of Ag + ions in the crystal structure present coordination number '6+1' and are surrounded by oxygen and nitrogen atoms of the nitridoosmate groups. Within the first of the two crystallographically distinguishable anions one can clearly differentiate between oxygen and nitrogen atoms while the second one exhibits a N/O disorder over two positions. The infrared spectrum of [Ag(NH 3 ) 2 ]Ag(OsO 3 N) 2 shows the typical absorptions which can be attributed to the complex anions and the NH 3 ligands

Crystal structure of bis(μ-3-nitrobenzoato-κ3O,O′:O;κ3O:O,O′-bis[bis(3-cyanopyridine-κN1(3-nitrobenzoato-κ2O,O′cadmium

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Tuncer Hökelek

2017-03-01

Full Text Available The asymmetric unit of the title compound, [Cd2(C7H4NO44(C6H4N24], contains one CdII atom, two 3-nitrobenzoate (NB anions and two 3-cyanopyridine (CPy ligands. The two CPy ligands act as monodentate N(pyridine-bonding ligands, while the two NB anions act as bidentate ligands through the carboxylate O atoms. The centrosymmetric dinuclear complex is generated by application of inversion symmetry, whereby the CdII atoms are bridged by the carboxylate O atoms of two symmetry-related NB anions, thus completing the distorted N2O5 pentagonal–bipyramidal coordination sphere of each CdII atom. The benzene and pyridine rings are oriented at dihedral angles of 10.02 (7 and 5.76 (9°, respectively. In the crystal, C—H...N hydrogen bonds link the molecules, enclosing R22(26 ring motifs, in which they are further linked via C—H...O hydrogen bonds, resulting in a three-dimensional network. In addition, π–π stacking interactions between parallel benzene rings and between parallel pyridine rings of adjacent molecules [shortest centroid-to-centroid distances = 3.885 (1 and 3.712 (1 Å, respectively], as well as a weak C—H...π interaction, may further stabilize the crystal structure.

Hemoglobin as a nitrite anhydrase: modeling methemoglobin-mediated N2O3 formation.

Science.gov (United States)

Hopmann, Kathrin H; Cardey, Bruno; Gladwin, Mark T; Kim-Shapiro, Daniel B; Ghosh, Abhik

2011-05-27

Nitrite has recently been recognized as a storage form of NO in blood and as playing a key role in hypoxic vasodilation. The nitrite ion is readily reduced to NO by hemoglobin in red blood cells, which, as it happens, also presents a conundrum. Given NO's enormous affinity for ferrous heme, a key question concerns how it escapes capture by hemoglobin as it diffuses out of the red cells and to the endothelium, where vasodilation takes place. Dinitrogen trioxide (N(2)O(3)) has been proposed as a vehicle that transports NO to the endothelium, where it dissociates to NO and NO(2). Although N(2)O(3) formation might be readily explained by the reaction Hb-Fe(3+)+NO(2)(-)+NO⇌Hb-Fe(2+)+N(2)O(3), the exact manner in which methemoglobin (Hb-Fe(3+)), nitrite and NO interact with one another is unclear. Both an "Hb-Fe(3+)-NO(2)(-)+NO" pathway and an "Hb-Fe(3+)-NO+NO(2)(-) " pathway have been proposed. Neither pathway has been established experimentally. Nor has there been any attempt until now to theoretically model N(2)O(3) formation, the so-called nitrite anhydrase reaction. Both pathways have been examined here in a detailed density functional theory (DFT, B3LYP/TZP) study and both have been found to be feasible based on energetics criteria. Modeling the "Hb-Fe(3+)-NO(2)(-)+NO" pathway proved complex. Not only are multiple linkage-isomeric (N- and O-coordinated) structures conceivable for methemoglobin-nitrite, multiple isomeric forms are also possible for N(2)O(3) (the lowest-energy state has an N-N-bonded nitronitrosyl structure, O(2)N-NO). We considered multiple spin states of methemoglobin-nitrite as well as ferromagnetic and antiferromagnetic coupling of the Fe(3+) and NO spins. Together, the isomerism and spin variables result in a diabolically complex combinatorial space of reaction pathways. Fortunately, transition states could be successfully calculated for the vast majority of these reaction channels, both M(S)=0 and M(S)=1. For a six-coordinate Fe(3+)-O

Crystal structure of tetrakis[μ2-2-(dimethylaminoethanolato-κ3N,O:O]di-μ3-hydroxido-dithiocyanato-κ2N-dichromium(IIIdilead(II dithiocyanate acetonitrile monosolvate

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Julia A. Rusanova

2016-04-01

Full Text Available The tetranuclear complex cation of the title compound, [Cr2Pb2(NCS2(OH2(C4H10NO4](SCN2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The CrIII ion is coordinated in a distorted octahedron, which involves two N atoms of one bidentate ligand and one thiocyanate anion, two μ2-O atoms of 2-(dimethylaminoethanolate ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the PbII ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb...S interactions involving the coordinating and non-coordinating thiocyanate anions are observed. In the crystal, the complex cations are linked through the thiocyanate anions via the Pb...S interactions and O—H...N hydrogen bonds into chains along the c axis. The chains are further linked together via S...S contacts. The contribution of the disordered solvent acetonitrile molecule was removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] procedure in PLATON. The solvent is included in the reported molecular formula, weight and density.

The gas-phase bis-uranyl nitrate complex ((UO2)2(NO3)5)-: infrared spectrum and structure

International Nuclear Information System (INIS)

Groenewold, G.S.; van Stipdonk, Michael J.; Oomens, Jos; De Jong, Wibe A.; McIlwain, Michael E.

2011-01-01

The infrared spectrum of the bis-uranyl nitrate complex ((UO 2 ) 2 (NO 3 ) 5 ) - was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate v 3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex ((UO 2 ) 2 (NO 3 ) 5 ) - compared to the mono-complex (UO 2 (NO 3 ) 3 ) - , as indicated by a higher O-U-O asymmetric stretching (v 3 ) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the v 3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The lowest energy structure predicted by density functional theory (B3LYP functional) calculations was one in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

The gas-phase bis-uranyl nitrate complex ((UO2)2(NO3)5)-: infrared spectrum and structure

International Nuclear Information System (INIS)

Groenewold, Gary S.; van Stipdonk, Michael J.; Oomens, Jos; de Jong, Wibe; McIlwain, Michael E.

2011-01-01

The infrared spectrum of the bis-uranyl nitrate complex ((UO 2 ) 2 (NO 3 ) 5 ) - was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate nu3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex ((UO 2 ) 2 (NO 3 ) 5 ) - compared to the mono-complex (UO 2 (NO 3 ) 3 ) - , as indicated by a higher O-U-O asymmetric stretching (nu3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the ν 3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The structure was calculated using density functional theory (B3LYP functional), which produced a structure in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

NO{sub x} reduction by coke deposited on Pt/Al{sub 2}O{sub 3} in an oxidizing medium; Elimination des NO{sub x} par le coke depose sur Pt/Al{sub 2}O{sub 3} en milieu oxydant

Energy Technology Data Exchange (ETDEWEB)

Lunati, S

1997-12-12

NO{sub x} reduction by coke deposited on Pt/Al{sub 2}O{sub 3} was studied in excess oxygen. Continuous analysis of the effluent was performed with a mass spectrometer. The coking reaction was carried out under reducing conditions with two different coking agents: cyclopentane and heptanal. In general, NO{sub x} reduction by coke deposited on Pt/Al{sub 2}O{sub 3} occurs in a wide temperature range (200 deg C2} ({approx}80%). Results show that the coke reducing ability and the temperature window depend closely on the chemical nature of the carbon deposits. Thereby, a coke made from heptanal which contains oxygenated functions (carbonyl and hydroxyl groups) within the carbon structure, is more selective and reduce NO{sub x} at lower temperature than a coke made from cyclopentane which does not contain these functional groups. Based on our results, we proposed a `dual-site` reaction for NO{sub x} reduction on coked Pt/Al{sub 2}O{sub 3} catalyst. Platinum allows O{sub 2} activation by dissociative adsorption, and NO{sub 2} formation by oxidation of NO. NO{sub x} reduction occurs on carbon deposits. Reaction between NO{sub x} and coke leads to the formation of N-containing species which are decomposed in CI{sub 2}, H{sub 2}O, N{sub 2} and N{sub 2}O by reaction with activated O{sub 2}. (author) 205 refs.

catena-Poly[[bis[2-(2,3-dimethylanilinobenzoato-κO]cadmium(II]-di-μ-3-pyridylmethanol-κ2N:O;κ2O:N

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Tadeusz Lis

2008-03-01

Full Text Available In the crystal structure of the title compound, [Cd(C15H14NO22(C6H7NO2]n, the Cd atom displays a distorted octahedral geometry, including two pyridine N atoms and two hydroxyl O from four symmetry-related 3-pyridylmethanol (3-pyme ligands and two carboxylate O atoms from mefenamate [2-(2,3-dimethylanilinobenzoate] anions. The Cd atoms are connected via the bridging 3-pyme ligands into chains, that extend in the a-axis direction. The Cd atom is located on a center of inversion, whereas the 3-pyme ligands and the mefenamate anions occupy general positions.

Influence of Background H2O on the Collision-Induced Dissociation Products Generated from [UO2NO3]+

Science.gov (United States)

Van Stipdonk, Michael J.; Iacovino, Anna; Tatosian, Irena

2018-04-01

Developing a comprehensive understanding of the reactivity of uranium-containing species remains an important goal in areas ranging from the development of nuclear fuel processing methods to studies of the migration and fate of the element in the environment. Electrospray ionization (ESI) is an effective way to generate gas-phase complexes containing uranium for subsequent studies of intrinsic structure and reactivity. Recent experiments by our group have demonstrated that the relatively low levels of residual H2O in a 2-D, linear ion trap (LIT) make it possible to examine fragmentation pathways and reactions not observed in earlier studies conducted with 3-D ion traps (Van Stipdonk et al. J. Am. Soc. Mass Spectrom. 14, 1205-1214, 2003). In the present study, we revisited the dissociation of complexes composed of uranyl nitrate cation [UVIO2(NO3)]+ coordinated by alcohol ligands (methanol and ethanol) using the 2-D LIT. With relatively low levels of background H2O, collision-induced dissociation (CID) of [UVIO2(NO3)]+ primarily creates [UO2(O2)]+ by the ejection of NO. However, CID (using He as collision gas) of [UVIO2(NO3)]+ creates [UO2(H2O)]+ and UO2 + when the 2-D LIT is used with higher levels of background H2O. Based on the results presented here, we propose that product ion spectrum in the previous experiments was the result of a two-step process: initial formation of [UVIO2(O2)]+ followed by rapid exchange of O2 for H2O by ion-molecule reaction. Our experiments illustrate the impact of residual H2O in ion trap instruments on the product ions generated by CID and provide a more accurate description of the intrinsic dissociation pathway for [UVIO2(NO3)]+. [Figure not available: see fulltext.

Reassessment of the NH4 NO3 thermal decomposition technique for calibration of the N2 O isotopic composition.

Science.gov (United States)

Mohn, Joachim; Gutjahr, Wilhelm; Toyoda, Sakae; Harris, Eliza; Ibraim, Erkan; Geilmann, Heike; Schleppi, Patrick; Kuhn, Thomas; Lehmann, Moritz F; Decock, Charlotte; Werner, Roland A; Yoshida, Naohiro; Brand, Willi A

2016-09-08

In the last few years, the study of N 2 O site-specific nitrogen isotope composition has been established as a powerful technique to disentangle N 2 O emission pathways. This trend has been accelerated by significant analytical progress in the field of isotope-ratio mass-spectrometry (IRMS) and more recently quantum cascade laser absorption spectroscopy (QCLAS). Methods The ammonium nitrate (NH 4 NO 3 ) decomposition technique provides a strategy to scale the 15 N site-specific (SP ≡ δ 15 N α - δ 15 N β ) and bulk (δ 15 N bulk  = (δ 15 N α  + δ 15 N β )/2) isotopic composition of N 2 O against the international standard for the 15 N/ 14 N isotope ratio (AIR-N 2 ). Within the current project 15 N fractionation effects during thermal decomposition of NH 4 NO 3 on the N 2 O site preference were studied using static and dynamic decomposition techniques. The validity of the NH 4 NO 3 decomposition technique to link NH 4 + and NO 3 - moiety-specific δ 15 N analysis by IRMS to the site-specific nitrogen isotopic composition of N 2 O was confirmed. However, the accuracy of this approach for the calibration of δ 15 N α and δ 15 N β values was found to be limited by non-quantitative NH 4 NO 3 decomposition in combination with substantially different isotope enrichment factors for the conversion of the NO 3 - or NH 4 + nitrogen atom into the α or β position of the N 2 O molecule. The study reveals that the completeness and reproducibility of the NH 4 NO 3 decomposition reaction currently confine the anchoring of N 2 O site-specific isotopic composition to the international isotope ratio scale AIR-N 2 . The authors suggest establishing a set of N 2 O isotope reference materials with appropriate site-specific isotopic composition, as community standards, to improve inter-laboratory compatibility. This article is protected by copyright. All rights reserved.

Heterospin systems constructed from [Cu2Ln]3+ and [Ni(mnt)2]1-,2- Tectons: First 3p-3d-4f complexes (mnt = maleonitriledithiolato).

Science.gov (United States)

Madalan, Augustin M; Avarvari, Narcis; Fourmigué, Marc; Clérac, Rodolphe; Chibotaru, Liviu F; Clima, Sergiu; Andruh, Marius

2008-02-04

New heterospin complexes have been obtained by combining the binuclear complexes [{Cu(H(2)O)L(1)}Ln(O(2)NO)(3)] or [{CuL(2)}Ln(O(2)NO)(3)] (L(1) = N,N'-propylene-di(3-methoxysalicylideneiminato); L(2) = N,N'-ethylene-di(3-methoxysalicylideneiminato); Ln = Gd(3+), Sm(3+), Tb(3+)), with the mononuclear [CuL(1)(2)] and the nickel dithiolene complexes [Ni(mnt)(2)](q)- (q = 1, 2; mnt = maleonitriledithiolate), as follows: (1)infinity[{CuL(1)}(2)Ln(O(2)NO){Ni(mnt)(2)}].Solv.CH(3)CN (Ln = Gd(3+), Solv = CH(3)OH (1), Ln = Sm(3+), Solv = CH(3)CN (2)) and [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)][Ni(mnt)(2)] (3) with [Ni(mnt)2]2-, [{(CH(3)CN)CuL(1)}(2)Ln(H(2)O)][Ni(mnt)(2)]3.2CH(3)CN (Ln = Gd(3+) (4), Sm(3+) (5), Tb(3+) (6)), and [{(CH(3)OH)CuL(2)}{CuL(2)}Gd(O(2)NO){Ni(mnt)(2)}][Ni(mnt)(2)].CH(2)Cl(2) (7) with [Ni(mnt))(2]*-. Trinuclear, almost linear, [CuLnCu] motifs are found in all the compounds. In the isostructural 1 and 2, two trans cyano groups from a [Ni(mnt)2]2- unit bridge two trimetallic nodes through axial coordination to the Cu centers, thus leading to the establishment of infinite chains. 3 is an ionic compound, containing discrete [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)](2+) cations and [Ni(mnt)(2)](2-) anions. Within the series 4-6, layers of discrete [CuLnCu](3+) motifs alternate with stacks of interacting [Ni(mnt)(2)](*-) radical anions, for which two overlap modes, providing two different types of stacks, can be disclosed. The strength of the intermolecular interactions between the open-shell species is estimated through extended Hückel calculations. In compound 7, [Ni(mnt)(2)](*-) radical anions coordinate group one of the Cu centers of a trinuclear [Cu(2)Gd] motif through a CN, while discrete [Ni(mnt)(2)](*-) units are also present, overlapping in between, but also with the coordinated ones. Furthermore, the [Cu(2)Gd] moieties dimerize each other upon linkage by two nitrato groups, both acting as chelate toward the gadolinium ion from one unit and monodentate toward a

Heteropolyhedral silver compounds containing the polydentate ligand N,N,O-E-[6-(hydroxyimino)ethyl]-1,3,7-trimethyllumazine. Preparation, spectral and XRD structural study and AIM calculations.

Science.gov (United States)

Jiménez-Pulido, Sonia B; Hueso-Ureña, Francisco; Fernández-Liencres, M Paz; Fernández-Gómez, Manuel; Moreno-Carretero, Miguel N

2013-01-14

The oxime derived from 6-acetyl-1,3,7-trimethyllumazine (1) ((E-6-(hydroxyimino)ethyl)-1,3,7-trimethylpteridine-2,4(1H,3H)-dione, DLMAceMox) has been prepared and its molecular and crystal structure determined from spectral and XRD data. The oxime ligand was reacted with silver nitrate, perchlorate, thiocyanate, trifluoromethylsulfonate and tetrafluoroborate to give complexes with formulas [Ag(2)(DLMAceMox)(2)(NO(3))(2)](n) (2), [Ag(2)(DLMAceMox)(2)(ClO(4))(2)](n) (3), [Ag(2)(DLMAceMox)(2)(SCN)(2)] (4), [Ag(2)(DLMAceMox)(2)(CF(3)SO(3))(2)(CH(3)CH(2)OH)]·CH(3)CH(2)OH (5) and [Ag(DLMAceMox)(2)]BF(4) (6). Single-crystal XRD studies show that the asymmetrical residual unit of complexes 2, 3 and 5 contains two quite different but connected silver centers (Ag1-Ag2, 2.9-3.2 Å). In addition to this, the Ag1 ion displays coordination with the N5 and O4 atoms from both lumazine moieties and a ligand (nitrato, perchlorato or ethanol) bridging to another disilver unit. The Ag2 ion is coordinated to the N61 oxime nitrogens, a monodentate and a (O,O)-bridging nitrato/perchlorato or two monodentate O-trifluoromethylsulfonato anions. The coordination polyhedra can be best described as a strongly distorted octahedron (around Ag1) and a square-based pyramid (around Ag2). The Ag-N and Ag-O bond lengths range between 2.22-2.41 and 2.40-2.67 Å, respectively. Although the structure of 4 cannot be resolved by XRD, it is likely to be similar to those described for 2, 3 and 5, containing Ag-Ag units with S-thiocyanato terminal ligands. Finally, the structure of the tetrafluoroborate compound 6 is mononuclear with a strongly distorted tetrahedral AgN(4) core (Ag-N, 2.27-2.43 Å). Always, the different Ag-N distances found clearly point to the more basic character of the oxime N61 nitrogen atom when compared with the pyrazine N5 one. A topological analysis of the electron density within the framework provided by the quantum theory of atoms in molecules (QTAIM) using DFT(M06L) levels of

Bis[2-(2-aminoethyl-1H-benzimidazole-κ2N2,N3](nitrato-κ2O,O′cobalt(II chloride trihydrate

Directory of Open Access Journals (Sweden)

Jing Zhao

2012-06-01

Full Text Available In the title compound, [Co(NO3(C9H11N32]Cl·3H2O, the CoII atom is coordinated by four N atoms from two chelating 2-(2-aminoethyl-1H-benzimidazole ligands and two O atoms from one nitrate anion in a distorted octahedral coordination environment. In the crystal, N—H...Cl, N—H...O, O—H...Cl and O—H...O hydrogen bonds link the complex cations, chloride anions and solvent water molecules into a three-dimensional network. π–π interactions between the imidazole and benzene rings and between the benzene rings are observed [centroid–centroid distances = 3.903 (3, 3.720 (3, 3.774 (3 and 3.926 (3 Å].

Electron spin resonance study of a-Cr2O3 and Cr2O3·nH2O quasi-spherical nanoparticles

CSIR Research Space (South Africa)

Khamlich, S

2011-12-01

Full Text Available The quasi-spherical nanoparticles of hydrated Cr2O3 · nH2O, and crystalline -Cr2O3, have been synthesized by reduction of the first row (3d) transition metal complex of K2Cr2O7. The temperaturedependence of electron spin resonance (ESR) spectrum...

Heterometallic cerium(IV) perrhenate, permanganate, and molybdate complexes supported by the imidodiphosphinate ligand [N(i-Pr2PO)2]-.

Science.gov (United States)

Wang, Guo-Cang; Sung, Herman H Y; Dai, Feng-Rong; Chiu, Wai-Hang; Wong, Wai-Yeung; Williams, Ian D; Leung, Wa-Hung

2013-03-04

Heterometallic cerium(IV) perrhenate, permanganate, and molybdate complexes containing the imidodiphosphinate ligand [N(i-Pr2PO)2](-) have been synthesized, and their reactivity was investigated. Treatment of Ce[N(i-Pr2PO)2]3Cl (1) with AgMO4 (M = Re, Mn) afforded Ce[N(i-Pr2PO)2]3(ReO4) (2) or Ce2[N(i-Pr2PO)2]6(MnO4)2 (3). In the solid state, 3 is composed of a [Ce2{N(i-Pr2PO)2}6(MnO4)](+) moiety featuring a weak Ce-OMn interaction [Ce-OMn distance = 2.528(8) Å] and a noncoordinating MnO4(-) counteranion. While 3 is stable in the solid state and acetonitrile solution, it decomposes readily in other organic solvents, such as CH2Cl2. 3 can oxidize ethylbenzene to acetophenone at room temperature. Treatment of 1 with AgBF4, followed by reaction with [n-Bu4N]2[MoO4], afforded [Ce{N(i-Pr2PO)2}3]2(μ-MoO4) (4). Reaction of trans-Ce[N(i-Pr2PO)2]2(NO3)2 (5), which was prepared from (NH4)2Ce(NO3)6 and K[N(i-Pr2PO)2], with 2 equiv of [n-Bu4N][Cp*MoO3] yielded trans-Ce[N(i-Pr2PO)2]2(Cp*MoO3)2 (6). 4 can catalyze the oxidation of methyl phenyl sulfide with tert-butyl hydroperoxide with high selectivity. The crystal structures of complexes 3-6 have been determined.

Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air

Science.gov (United States)

Crowley, J. N.; Thieser, J.; Tang, M. J.; Schuster, G.; Bozem, H.; Beygi, Z. H.; Fischer, H.; Diesch, J.-M.; Drewnick, F.; Borrmann, S.; Song, W.; Yassaa, N.; Williams, J.; Pöhler, D.; Platt, U.; Lelieveld, J.

2011-11-01

Nighttime mixing ratios of boundary layer N2O5 were determined using cavity-ring-down spectroscopy during the DOMINO campaign in Southern Spain (Diel Oxidant Mechanisms In relation to Nitrogen Oxides, 21 November 2008-8 December 2008). N2O5 mixing ratios ranged from below the detection limit (~5 ppt) to ~500 ppt. A steady-state analysis constrained by measured mixing ratios of N2O5, NO2 and O3 was used to derive NO3 lifetimes and compare them to calculated rates of loss via gas-phase and heterogeneous reactions of both NO3 and N2O5. Three distinct types of air masses were encountered, which were largely marine (Atlantic), continental or urban-industrial in origin. NO3 lifetimes were longest in the Atlantic sector (up to ~30 min) but were very short (a few seconds) in polluted, air masses from the local city and petroleum-related industrial complex of Huelva. Air from the continental sector was an intermediate case. The high reactivity to NO3 of the urban air mass was not accounted for by gas-phase and heterogeneous reactions, rates of which were constrained by measurements of NO, volatile organic species and aerosol surface area. In general, high NO2 mixing ratios were associated with low NO3 lifetimes, though heterogeneous processes (e.g. reaction of N2O5 on aerosol) were generally less important than direct gas-phase losses of NO3. The presence of SO2 at levels above ~2 ppb in the urban air sector was always associated with very low N2O5 mixing ratios indicating either very short NO3 lifetimes in the presence of combustion-related emissions or an important role for reduced sulphur species in urban, nighttime chemistry. High production rates coupled with low lifetimes of NO3 imply an important contribution of nighttime chemistry to removal of both NOx and VOC.

Variable lifetimes and loss mechanisms for NO3 and N2O5 during the DOMINO campaign: contrasts between marine, urban and continental air

Directory of Open Access Journals (Sweden)

J. Williams

2011-11-01

Full Text Available Nighttime mixing ratios of boundary layer N2O5 were determined using cavity-ring-down spectroscopy during the DOMINO campaign in Southern Spain (Diel Oxidant Mechanisms In relation to Nitrogen Oxides, 21 November 2008–8 December 2008. N2O5 mixing ratios ranged from below the detection limit (~5 ppt to ~500 ppt. A steady-state analysis constrained by measured mixing ratios of N2O5, NO2 and O3 was used to derive NO3 lifetimes and compare them to calculated rates of loss via gas-phase and heterogeneous reactions of both NO3 and N2O5. Three distinct types of air masses were encountered, which were largely marine (Atlantic, continental or urban-industrial in origin. NO3 lifetimes were longest in the Atlantic sector (up to ~30 min but were very short (a few seconds in polluted, air masses from the local city and petroleum-related industrial complex of Huelva. Air from the continental sector was an intermediate case. The high reactivity to NO3 of the urban air mass was not accounted for by gas-phase and heterogeneous reactions, rates of which were constrained by measurements of NO, volatile organic species and aerosol surface area. In general, high NO2 mixing ratios were associated with low NO3 lifetimes, though heterogeneous processes (e.g. reaction of N2O5 on aerosol were generally less important than direct gas-phase losses of NO3. The presence of SO2 at levels above ~2 ppb in the urban air sector was always associated with very low N2O5 mixing ratios indicating either very short NO3 lifetimes in the presence of combustion-related emissions or an important role for reduced sulphur species in urban, nighttime chemistry. High production rates coupled with low lifetimes of NO3 imply an important contribution of nighttime chemistry to removal of both NOx and VOC.

Water-containing derivative phases of the Srn+1FenO3n+1 series

International Nuclear Information System (INIS)

Lehtimaeki, M.; Hirasa, A.; Matvejeff, M.; Yamauchi, H.; Karppinen, M.

2007-01-01

The n=1, 2, 3 and ∞ members of the homologous series Sr n+1 Fe n O 3n+1 of layered iron oxides are investigated for their tendency to accept additional layers of water in their crystals. The phases possess a Ruddlesden-Popper-type SrO-(SrO-FeO 2 ) n crystal structure, where the n=∞ limit is nothing but the perovskite structure. It is revealed that the n=1, 2 and 3 phases readily accommodate one or two layers of water between adjacent SrO layers, whereas the n=∞ member which lacks the SrO-SrO double-layer unit remains intact in the presence of water. The speed of the water intercalation process is found to decrease with increasing n. Among the layered water derivatives, the n=2 phase with two water molecules per formula unit, i.e. Sr 3 Fe 2 O 7 .2H 2 O, was found to be most stable. - Graphical abstract: Water-containing derivative phases obtained from the homologous series of Sr n+1 Fe n O 3n+1 Ruddlesden-Popper phases through topotactic water intercalation

Magneto, spectral and thermal studies of lanthanum and lanthanide(3) bromide and nitrate complexes of 2,2'bipyridine mono N-oxide

International Nuclear Information System (INIS)

Agarwal, R.K.

1988-01-01

Lanthanide(3) bromide and nitrate complexes of 2,2'-bipyridine mono N-oxide (BipyNO) having the composition Ln(BipyNO) 3 Br 3 and Ln(BipyNO) 2 (NO 3 ) 3 (Ln=La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Yb) have been prepared and characterized by means of conductance, molecular weight, magnetic and spectral studies. The ligand acts as a bidentate O,N-chelating agent. The coordination number nine or ten for lanthanide ions has been assigned to these complexes. 3 tabs., 25 refs. (author)

[(E-2-(3,5-Dibromo-2-oxidobenzylideneamino-3-(4-hydroxyphenylpropionato-κ3O,N,O′](dimethylformamide-κOcopper(II

Directory of Open Access Journals (Sweden)

Hong Liang

2008-04-01

Full Text Available In the title complex, [Cu(C16H11Br2NO4(C3H7NO]2, there are two unique molecules in the asymmetric unit. Each CuII atom is coordinated by two O atoms and one N atom from the tridentate ligand L2− [LH2 = (E-2-(3,5-dibromo-2-hydroxybenzylideneamino-2-(4-hydroxyphenylacetic acid] and the O atom of a dimethylformamide molecule to give a slightly distorted square-planar geometry. The two unique molecules form a dimer through weak C—H...O hydrogen bonds. In the dimer, the Cu...Cu distance is 3.712 (1 Å. In the crystal structure, molecules form a one-dimensional chain through C—H...O hydrogen bonds. These are further aggregated into a three-dimensional network by O—H...O and C—H...O hydrogen bonds.

Crystal structure of poly[[hexaqua-1κ4O,2κ2O-bis(μ3-pyridine-2,4-dicarboxylato-1κO2:2κ2N,O2′;1′κO4cobalt(IIstrontium(II] dihydrate

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Zhaojun Yu

2015-09-01

Full Text Available In the title polymeric complex, {[CoSr(C7H3NO42(H2O6]·2H2O}n, the CoII ion, which is situated on a crystallographic centre of inversion, is six-coordinated by two O atoms and two N atoms from two pyridine-2,4-dicarboxylate (pydc2− ligands and two terminal water molecules in a slightly distorted octahedral geometry, to form a trans-[Co(pydc2(H2O2]2− unit. The SrII ion, situated on a C2 axis, is coordinated by four O atoms from four pydc2− ligands and four water molecules. The coordination geometry of the SrII atom can be best described as a distorted dodecahedron. Each SrII ion bridges four [Co(pydc2(H2O2]2− units by four COO− groups of four pydc2− ligands to form a three-dimensional network structure. Two additional solvent water molecules are observed in the crystal structure and are connected to the three-dimensional coordination polymer by O—H...O hydrogen bonds. Further intra- and intermolecular O—H...O hydrogen bonds consolidate the overall structure.

Gold(I) Complexes with N-Donor Ligands. 2.(1) Reactions of Ammonium Salts with [Au(acac-kappaC(2))(PR(3))] To Give [Au(NH(3))L](+), [(AuL)(2)(&mgr;(2)-NH(2))](+), [(AuL)(4)(&mgr;(4)-N)](+), or [(AuL)(3)(&mgr;(3)-O)](+). A New and Facile Synthesis of [Au(NH(3))(2)](+) Salts. Crystal Structure of [{AuP(C(6)H(4)OMe-4)(3)}(3)(&mgr;(3)-O)]CF(3)SO(3).

Science.gov (United States)

Vicente, José; Chicote, María-Teresa; Guerrero, Rita; Jones, Peter G.; Ramírez De Arellano, M. Carmen

1997-09-24

The complexes [Au(acac-kappaC(2))(PR(3))] (acac = acetylacetonate, R = Ph, C(6)H(4)OMe-4) react with (NH(4))ClO(4) to give amminegold(I), [Au(NH(3))(PR(3))]ClO(4), amidogold(I), [(AuPR(3))(2)(&mgr;(2)-NH(2))]ClO(4), or nitridogold(I), [(AuPR(3))(4)(&mgr;(4)-N)]ClO(4), complexes, depending on the reaction conditions. Similarly, [Au(acac-kappaC(2))(PPh(3))] reacts with (NH(3)R')OTf (OTf = CF(3)SO(3)) (1:1) or with [H(3)N(CH(2))(2)NH(2)]OTf (1:1) to give (amine)gold(I) complexes [Au(NH(2)R')(PPh(3))]OTf (R' = Me, C(6)H(4)NO(2)-4) or [(AuPPh(3))(2){&mgr;(2)-H(2)N(CH(2))(2)NH(2)}](OTf)(2), respectively. The ammonium salts (NH(2)R'(2))OTf (R' = Et, Ph) react with [Au(acac-kappaC(2))(PR(3))] (R = Ph, C(6)H(4)OMe-4) (1:2) to give, after hydrolysis, the oxonium salts [(AuPR(3))(3)(&mgr;(3)-O)]OTf (R = Ph, C(6)H(4)OMe-4). When NH(3) is bubbled through a solution of [AuCl(tht)] (tht = tetrahydrothiophene), the complex [Au(NH(3))(2)]Cl precipitates. Addition of [Au(NH(3))(2)]Cl to a solution of AgClO(4) or TlOTf leads to the isolation of [Au(NH(3))(2)]ClO(4) or [Au(NH(3))(2)]OTf, respectively. The crystal structure of [(AuPR(3))(3)(&mgr;(3)-O)]OTf.Me(2)CO (R = C(6)H(4)OMe-4) has been determined: triclinic, space group P&onemacr;, a = 14.884(3) Å, b = 15.828(3) Å, c = 16.061(3) Å, alpha = 83.39(3) degrees, beta = 86.28(3) degrees, gamma = 65.54(3) degrees, R1 (wR2) = 0.0370 (0.0788). The [(AuPR(3))(3)(&mgr;(3)-O)](+) cation shows an essentially trigonal pyramidal array of three gold atoms and one oxygen atom with O-Au-P bond angles of ca. 175 degrees and Au.Au contacts in the range 2.9585(7)-3.0505(14) Å. These cations are linked into centrosymmetric dimers through two short Au.Au [2.9585(7), 3.0919(9) Å] contacts. The gold atoms of the dimer form a six-membered ring with a chair conformation.

Room and high temperature interactions in sodium and rubidium rich ternary nitrate mixtures of UO2(NO3)2.6H2O - NaNO3 - RbNO3

International Nuclear Information System (INIS)

Kalekar, Bhupesh B.; Reddy, A.V.R.; Raje, Naina

2016-01-01

High temperature interaction behavior of nitrates is important for characterizing different intermediate products and their thermal stabilities during the calcination of nuclear waste before their immobilization in the stable glass matrix. Mixtures of UO 2 (NO 3 ) 2 .6H 2 O (UNH) with NaNO 3 (NaN) and RbNO 3 (RbN) were prepared by mixing the weighed amounts of component nitrates and grinding gently in a mortar and pestle. The mixing and grinding of individual nitrate components in a mortar with pestle showed the agglomeration of solid particles and subsequent dissolution probably in the water of crystallization of UNH. The continued grinding and mixing showed the reappearance of the solid powder. The original yellow color of the mixture was changed to greenish yellow color. The mixtures were subjected to thermal measurements using Netzsch Thermobalance (Model No.: STA 409 PC Luxx) coupled to Bruker FTIR system (Model No.: Tensor 27) via a heated Teflon capillary (1 m long, 2 mm i.d.). TG - DTG curves of equimolar mixture are displayed. The plateau was observed on TG curve in the temperature region of 31- 250 °C. It is reported that Na(UO 2 (NO 3 ) 3 ).H 2 O and Rb(UO 2 (NO 3 ) 3 ) formed around 250 °C in the equimolar nitrate mixtures of UNH-NaN and UNH-RbN. Thermal and XRD results indicated the formation of Na(UO 2 (NO 3 ) 3 ).H 2 O and Rb(UO 2 (NO) 3 ) 3 ) even by mixing the UNH, NaN and RbN in equimolar ratios at room temperature

Theoretical study of [Li(H2O)n]+ and [K(H2O)n]+ (n = 1-4) complexes

International Nuclear Information System (INIS)

Wojcik, M.J.; Mains, G.J.; Devlin, J.P.

1995-01-01

The geometries, successive binding energies, vibrational frequencies, and infrared intensities are calculated for the [Li(H 2 O) n ] + and [K(H 2 O) n ] + (n = 1-4) complexes. The basis sets used are 6-31G * and LANL1DZ (Los Alamos ECP+DZ) at the SCF and MP2 levels. There is an agreement for calculated structures and frequencies between the MP2/6-31G * and MP2/LANL1DZ basis sets, which indicates that the latter can be used for calculations of water complexes with heavier ions. Our results are in a reasonable agreement with available experimental data and facilitate experimental study of these complexes. 19 refs., 4 figs., 6 tabs

Atmospheric chemistry of CF3C(O)O2 radicals. Kinetics of their reaction with NO2 and kinetics of the thermal decomposition of the product CF3C(O)O2NO2

DEFF Research Database (Denmark)

Wallington, T.J.; Sehested, J.; Nielsen, O.J.

1994-01-01

A pulse radiolysis technique has been used to measure a rate constant of (6.6 +/- 1.3) x 10(-12) cm3 molecule-1 s-1 for the association reaction between CF3C(O)O2 radicals and NO2 at 295 K and one atmosphere total pressure of SF6 diluent. A FTIR/smog chamber system was used to study the thermal...... decomposition CF3C(O)O2NO2. The rate of decomposition of CF3C(O)O2NO2 was independent of the total pressure of N2 diluent over the range 100-700 Torr and was fit by the expression k-1 = (1.9(-1.5)+7.6) x 10(16) exp[(-14000 +/- 480)/T] s-1. Implications for the atmospheric chemistry of CFC replacements...

Pb4(OH)4(BrO3)3(NO3): An Example of SHG Crystal in Metal Bromates Containing π-Conjugated Planar Triangle.

Science.gov (United States)

Kong, Fang; Hu, Chun-Li; Liang, Ming-Li; Mao, Jiang-Gao

2016-01-19

The first example of SHG crystal in the metal bromates containing π-conjugated planar triangle systems, namely, Pb4(OH)4(BrO3)3(NO3), was successfully synthesized via the hydrothermal method. Furthermore, a single crystal of centrosymmetric Pb8O(OH)6(BrO3)6(NO3)2·H2O was also obtained. Both compounds contain similar [Pb4(OH)4] cubane-like tetranuclear clusters, but they display different one-dimensional (1D) chain structures. Pb4(OH)4(BrO3)3(NO3) features a zigzag [Pb4(OH)4(BrO3)3](+) 1D chain, while Pb8O(OH)6(BrO3)6(NO3)2·H2O is composed of two different orthogonal chains: the linear [Pb4(OH)4(BrO3)2](2+) 1D chain along the b-axis and the zigzag [Pb4O2(OH)2(BrO3)4](2-) 1D chain along the a-axis. The NO3 planar triangles of the compounds are all isolated and located in the spaces of the structures. Pb4(OH)4(BrO3)3(NO3) exhibits the first example of SHG crystal in the metal bromates with π-conjugated planar triangle. The second-harmonic generation (SHG) efficiency of Pb4(OH)4(BrO3)3(NO3) is approximately equal to that of KDP and it is phase-matchable. Dipole moment and theory calculations indicate that BrO3, NO3, and PbO4 groups are the origin of its SHG efficiency, although some of the contributions cancel each other out.

(μ-3-Acetyl-5-carboxylato-4-methylpyrazolido-1:2κ4N2,O3:N1,O5-μ-chlorido-tetrapyridine-1κ2N,2κ2N-chlorido-1κCl-dicopper(II propan-2-ol solvate

Directory of Open Access Journals (Sweden)

Sergey Malinkin

2009-10-01

Full Text Available The title compound, [Cu2(C7H6N2O3Cl2(C5H5N4]·C3H8O, is a binuclear pyrazolate complex, in which the two CuII atoms have different coordination numbers and are connected by a bridging Cl atom. One CuII atom has a distorted square-pyramidal coordination environment formed by two pyridine N atoms, one bridging Cl atom and an N,O-chelating pyrazolate ligand. The other CuII atom adopts an octahedral geometry defined by two pyridine N atoms at the axial positions, two Cl atoms and the coordinated pyrazolate ligand in the equatorial plane. An O—H...O hydrogen bond connects the complex molecules and propan-2-ol solvent molecules into pairs. These pairs form columns along the a axis.

Nanosized As2O3/Fe2O3 complexes combined with magnetic fluid hyperthermia selectively target liver cancer cells.

Science.gov (United States)

Wang, Zi-Yu; Song, Jian; Zhang, Dong-Sheng

2009-06-28

To study the methods of preparing the magnetic nano-microspheres of Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) complexes and their therapeutic effects with magnetic fluid hyperthermia (MFH). Nanospheres were prepared by chemical co-precipitation and their shape and diameter were observed. Hemolysis, micronucleus, cell viability, and LD(50) along with other in vivo tests were performed to evaluate the Fe(2)O(3) microsphere biocompatibility. The inhibition ratio of tumors after Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) injections combined with induced hyperthermia in xenograft human hepatocarcinoma was calculated. Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) particles were round with an average diameter of 20 nm and 100 nm as observed under transmission electron microscope. Upon exposure to an alternating magnetic field (AMF), the temperature of the suspension of magnetic particles increased to 41-51 degrees C, depending on different particle concentrations, and remained stable thereafter. Nanosized Fe(2)O(3) microspheres are a new kind of biomaterial without cytotoxic effects. The LD(50) of both Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) in mice was higher than 5 g/kg. One to four weeks after Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) complex injections into healthy pig livers, no significant differences were found in serum AST, ALT, BUN and Cr levels among the pigs of all groups (P > 0.05), and no obvious pathological alterations were observed. After exposure to alternating magnetic fields, the inhibition ratio of the tumors was significantly different from controls in the Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) groups (68.74% and 82.79%, respectively; P < 0.01). Tumors of mice in treatment groups showed obvious necrosis, while normal tissues adjoining the tumor and internal organs did not. Fe(2)O(3) and As(2)O(3)/Fe(2)O(3) complexes exerted radiofrequency-induced hyperthermia and drug toxicity on tumors without any liver or kidney damage. Therefore, nanospheres are ideal carriers for tumor-targeted therapy.

Redox and catalytic properties of new polypyrrole modified electrodes functionalized by [Ru(bpea)(bpy)H{sub 2}O]{sup 2+} complexes; bpea=N,N'-bis(2-pyridylmethyl)ethylamine, bpy=2,2'-bipyridine

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Montserrat; Romero, Isabel; Sens, Cristina; Llobet, Antoni; Deronzier, Alain

2003-04-05

New ruthenium(II) complexes containing one or two pyrrole-functionalized polypyridylic ligands have been prepared in order to study their electrochemical behaviour in heterogeneous phase, after anodic polymerization from CH{sub 2}Cl{sub 2} solution on an electrode surface. Complexes containing one pyrrole unit have general formula [Ru(bpea-pyr)(bpy)(L)]{sup 2+} (bpea-pyr=N-[3-bis(2-pyridylmethyl)aminopropyl]pyrrole, bpy=2,2'-bipyridine, L=Cl, complex 3, or L=H{sub 2}O, complex 1), whereas compounds having two pyrrole units correspond to [Ru(bpea-pyr)(bpy-pyr)(L)]{sup 2+} (bpy-pyr=4-methyl-4'-pyrrolylbutyl-2,2'-bipyridine, L=Cl, complex 4, or L=H{sub 2}O, complex 2). Upon oxidative polymerization, all complexes form highly stable polypyrrolic films on a graphite disk electrode surface. An electrode modified with complex 2 polypyrrole coating film, C/poly-2, has been tested as heterogeneous catalyst for the oxidation of benzyl alcohol, showing a remarkably high efficiency and notably improving the results obtained with analogous complexes in homogeneous phase.

High-Pressure Synthesis and Study of NO+NO3− and NO2+NO3− Ionic Solids

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A. Yu. Kuznetsov

2009-01-01

Full Text Available Nitrosonium-nitrate NO+NO3− and dinitrogen pentoxide NO2+NO3− ionic crystals were synthesized by laser heating of a condensed oxygen-rich O2-N2 mixture compressed to different pressures, up to 40 GPa, in a diamond anvil cell (DAC. High-pressure/high-temperature Raman and X-ray diffraction studies of synthesized samples disclosed a transformation of NO+NO3− compound to NO2+NO3− crystal at temperatures above ambient and pressures below 9 GPa. High-pressure experiments revealed previously unreported bands in Raman spectra of NO+NO3− and NO2+NO3− ionic crystals. Structural properties of both ionic compounds are analyzed. Obtained experimental results support a hypothesis of a rotational disorder of NO+ complexes in NO+NO3− and indicate a rotational disorder of ionic complexes in NO2+NO3− solid.

cyclo-Tetrakis(μ-3-acetyl-4-methyl-1H-pyrazole-5-carboxylato-κ4N2,O3:N1,O5tetrakis[aquacopper(II] tetradecahydrate

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Sergey Malinkin

2011-09-01

Full Text Available The title compound, [Cu4(C7H6N2O34(H2O4]·14H2O, a tetranuclear [2 × 2] grid-type complex with S4 symmetry, contains four CuII atoms which are bridged by four pyrazolecarboxylate ligand anions and are additionally bonded to a water molecule. Each CuII atom is coordinated by two O atoms of the carboxylate and acetyl groups, two pyrazole N atoms of doubly deprotonated 3-acetyl-4-methyl-1H-pyrazole-5-carboxylic acid and one O atom of a water molecule. The geometry at each CuII atom is distorted square-pyramidal, with the two N and two O atoms in the equatorial plane and O atoms in the axial positions. O—H...O hydrogen-bonding interactions additionally stabilize the structure. One of the uncoordinated water molecules shows half-occupancy.

Bis[2-(2-pyridylmethyleneaminobenzenesulfonato-κ3N,N′,O]cadmium(II dihydrate

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Miao Ou-Yang

2008-11-01

Full Text Available The title complex, [Cd(Paba2]·2H2O or [Cd(C12H9N2O3S2]·2H2O, was synthesized by the reaction of the potassium salt of 2-(2-pyridylmethyleneaminobenzenesulfonic acid (PabaK with CdCl2·2.5H2O in methanol. The CdII atom lies on a crystallographic twofold axis and is coordinated by four N atoms and two O atoms from two deprotonated tridentate 2-(2-pyridylmethyleneaminobenzenesulfonate ligands in a slightly distorted octahedral environment. There are extensive hydrogen bonds of the type O—H...O between the uncoordinated water molecules and the sulfonate O atoms, through which the complex forms a layered structure parallel to (001.

Effect of rutile TiO{sub 2} on the photocatalytic performance of g-C{sub 3}N{sub 4}/brookite-TiO{sub 2-x}N{sub y} photocatalyst for NO decomposition

Energy Technology Data Exchange (ETDEWEB)

Li, Huihui, E-mail: lihh@lzu.edu.cn [Key Laboratory for Magnetism Magnetic Materials of the Ministry of Education, Lanzhou University, 222 south Tianshui Road, Lanzhou, 730000 (China); Wu, Xiaoyong [Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Yin, Shu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Katsumata, Kenichi [Photocatalysis International Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510 (Japan); Wang, Yuhua [Key Laboratory for Magnetism Magnetic Materials of the Ministry of Education, Lanzhou University, 222 south Tianshui Road, Lanzhou, 730000 (China)

2017-01-15

Graphical abstract: g-C{sub 3}N{sub 4}/rutile-brookite TiO{sub 2-x}Ny forms a Z-scheme photocatalytic system, which shows improvement on the photocatalytic activity than that of g-C{sub 3}N{sub 4}/single brookite TiO{sub 2-x}N{sub y}. - Highlights: • g-C{sub 3}N{sub 4}/rutile-brookite TiO{sub 2-x}N{sub y} forms a Z-scheme photocatalytic system. • Photogenerated electrons can efficiently transfer from rutile TiO{sub 2} to g-C{sub 3}N{sub 4}. • Single brookite TiO{sub 2-x}N{sub y} shows lower photo-utilization efficiency than rutile-brookite mixed one. • DeNO{sub x} activities of brookite TiO{sub 2-x}N{sub y} hybrids decrease with g-C{sub 3}N{sub 4} amount increase. - Abstract: Novel g-C{sub 3}N{sub 4}/rutile-brookite TiO{sub 2-x}N{sub y} composite photocatalysts were fabricated through a facile solvothermal approach. The effect of rutile phase TiO{sub 2} with brookite TiO{sub 2} and g-C{sub 3}N{sub 4} on the photocatalytic activity of g-C{sub 3}N{sub 4}/nitrogen-doped TiO{sub 2} composite was studied. The photocatalytic performance of the photocatalyst was evaluated by measuring the degradation of NO gas under visible and UV light irradiation. It is suggested that g-C{sub 3}N{sub 4}/rutile-brookite TiO{sub 2-x}N{sub y} forms a Z-scheme photocatalytic system, which shows improvement on the photocatalytic activity than that of g-C{sub 3}N{sub 4}/single brookite TiO{sub 2-x}N{sub y}. By importing rutile phase TiO{sub 2-x}N{sub y}, the photogenerated electrons can efficiently transfer from rutile TiO{sub 2} to g-C{sub 3}N{sub 4}, which results in the separation of electron and hole pairs, enhancing the photocatalytic ability. However, single brookite TiO{sub 2-x}N{sub y} can not remove the photogenerated electrons efficiently and the photocatalytic performances of composites decrease with g-C{sub 3}N{sub 4} amount increase.

Solution Synthesis, Structure, and CO2 Reduction Reactivity of a Scandium(II) Complex, {Sc[N(SiMe3 )2 ]3 }.

Science.gov (United States)

Woen, David H; Chen, Guo P; Ziller, Joseph W; Boyle, Timothy J; Furche, Filipp; Evans, William J

2017-02-13

The first crystallographically characterizable complex of Sc 2+ , [Sc(NR 2 ) 3 ] - (R=SiMe 3 ), has been obtained by LnA 3 /M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR 2 ) 3 with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)] + , [K(18-c-6)] + , and [Cs(crypt)] + salts of the [Sc(NR 2 ) 3 ] - anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 45 Sc nucleus. The Sc(NR 2 ) 3 reduction differs from Ln(NR 2 ) 3 reactions (Ln=Y and lanthanides) in that it occurs under N 2 without formation of isolable reduced dinitrogen species. [K(18-c-6)][Sc(NR 2 ) 3 ] reacts with CO 2 to produce an oxalate complex, {K 2 (18-c-6) 3 }{[(R 2 N) 3 Sc] 2 (μ-C 2 O 4 -κ 1 O:κ 1 O'')}, and a CO 2 - radical anion complex, [(R 2 N) 3 Sc(μ-OCO-κ 1 O:κ 1 O')K(18-c-6)] n . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Formation of nitrogen complexes when [Ru(NH3)5H2O]2+ ion reaction with diazo-acetic ester and aromatic salts of diazonium

International Nuclear Information System (INIS)

Shur, V.B.; Tikhonova, I.A.; Vol'pin, M.E.

1978-01-01

A possibility of formation of nitrogen complexes during transition metal compound interaction with aliphatic and aromatic diazo compounds is studied. It is shown that at the interaction of [Ru(NH 3 ) 5 H 2 O] 2+ with diazo-acetic ester in water (pH7) at 20 deg, quick splitting of the CN-bond in the ester molecule takes place with the formation of [Ru(NH 3 ) 5 N 2 ] 2+ and [(NH 3 ) 5 RuN 2 Ru(NH 3 ) 5 ] 4+ (NRRN) nitrogen complexes. The sum yield of complexes comprises 86% taking into acount diazo-acetic ester. Aromatic salts of diazonium, n-O 3 SC 6 H 4 N 2 and p-quinone diazide react with the [Ru(NH 3 ) 5 H 2 O] 2+ excess forming NRRN (the yield equals 40-53%). The reaction mechanism is discussed

Crystal structure of triaqua(1,10-phenanthroline-κ2N,N′(2,4,5-trifluoro-3-methoxybenzoato-κO1cobalt(II 2,4,5-trifluoro-3-methoxybenzoate

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Junshan Sun

2014-11-01

Full Text Available The title salt, [Co(C8H4F3O3(C12H8N2(H2O3](C8H4F3O3, was obtained under solvothermal conditions by the reaction of 2,4,5-trifluoro-3-methoxybenzoic acid with CoCl2 in the presence of 1,10-phenanthroline (phen. The CoII ion is octahedrally coordinated by two N atoms [Co—N = 2.165 (2 and 2.129 (2 Å] from the phen ligand, by one carboxylate O atom [Co—O = 2.107 (1 Å] and by three O atoms from water molecules [Co—O = 2.093 (1, 2.102 (1 and 2.114 (1 Å]. The equatorial positions of the slightly distorted octahedron are occupied by the N atoms, the carboxylate O and one water O atom. An intra- and intermolecular O—H...O hydrogen-bonding network between the water-containing complex cation and the organic anion leads to the formation of ribbons parallel to [010].

Synthesis, electrochemistry, and spectroscopic properties of six-coordinate monooxomolybdenum(VI) complexes containing tridentate Schiff base and bidentate catecholate ligands. Crystal and molecular structure of (N-salicylidene-2-aminophenolato)(naphthalene-2,3-diolato)oxomolybdenum(VI)

International Nuclear Information System (INIS)

Mondal, J.U.; Schultz, F.A.; Brennan, T.D.; Scheidt, W.R.

1988-01-01

Six-coordinate monooxomolybdenum(VI) complexes, MoO(cat)(Sap), where Sap 2- = the Schiff base dianion N-salicylidene-2-aminophenolate and cat 2- = catecholate Cat 2- , naphthalene-2,3-diolate (Naphcat 2- ), or 3,5-di-tert-butylcatecholate (DTBcat 2- ), are prepared by reacting the Mo(VI) dimer. [MoO 2 (Sap)] 2 , with the appropriate catechol. The products are characterized by cyclic voltammetry, mass spectrometry, and uv/vis, ir, and 95 Mo NMR spectroscopy. The MoO(cat)(Sap) complexes represent the first examples of a mononuclear MoO 4+ center with a coordination number of six. The crystal structure of the MoO-(Naphcat)(Sap) derivative is reported, confirming the six-coordinate, distorted octahedrla environment about Mo(VI). Bond angles in the coordination group deviate from the ideal value of 90/degrees/ as a consequence of the ligand bite constraints and because all four O-Mo-O angles involving the terminal oxo ligand are larger than the ideal 90/degrees/ value. MoO(cat)(Sap) complexes undergo reversible one-electronic reduction at -0.5 to -0.7 V versus Fc /sup +/0/ followed by irreversible one-electron reduction at -1.6 to -1.9 V. Reversible MoO 4+ /MoO 3+ electrochemistry is attributed to the fact that the Mo d/sub xy/orbital of MoO(cat)(Sap) can be singly occupied upon reduction to Mo(V) without unfavorable interaction with the four bonds in its equatorial plane. This contrasts with the irreversible electrochemical behavior of seven-coordinate MoO 4+ complexes, which contain five such bonds. The 95 Mo NMR chemical shift of MoO(Naphcat)(Sap) is +385 ppM versus external molybdate; this value is highly deshielded with respect to seven-coordinate MoO 4+ and six-coordinate MoO 2 2+ complexes with O and N donors. 35 references, 4 figures, 5 tables

Tetra-, Penta- and Hexa-Coordinated Transition Metal Complexes Constructed from Coumarin-Containing N2O2 Ligand

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Lei Gao

2018-02-01

Full Text Available Three newly designed complexes, [Cu(L]·CHCl3 (1, [Co(L(MeOH]·CHCl3 (2 and [{Ni(L(MeOH(PhCOO}2Ni] (3 a coumarin-containing Salamo-type chelating ligand (H2L have been synthesized and characterized by elemental analyses, IR and UV-VIS spectra, and X-ray crystallography. Complex 1 includes one Cu(II atom, one completely deprotonated (L2− unit and one crystalling chloroform molecule, the Cu(II atom shows a square-planar geometry. Complex 2 includes one Co(II atom, one completely deprotonated (L2− unit, one coordinated methanol molecule and one crystalling chloroform molecule. The Co(II atom is a distorted trigonal-bipyramidal geometry. While complex 3 includes three Ni(II atoms, two completely deprotonated (L2− units, two benzoates and two coordinated methanol molecules. The complexes 1 and 2 are both possess three-dimensional supra-molecular structures by abundant noncovalent interactions. But, complex 3 formed a two-dimensional supra-molecular structure by intra-molecular hydrogen bonds. In addition, the antimicrobial and fluorescence properties of H2L and its complexes 1, 2 and 3 were also investigated.

Synthesis, structure, and characterization of two new bismuth(III) selenite/tellurite nitrates: [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3)

Science.gov (United States)

Meng, Chang-Yu; Wei, Ming-Fang; Geng, Lei; Hu, Pei-Qing; Yu, Meng-Xia; Cheng, Wen-Dan

2016-07-01

Two new bismuth(III) selenite/tellurite nitrates, [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV-vis-NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P21/c with a=9.9403(4) Å, b=9.6857(4) Å, c=10.6864(5) Å, β=93.1150(10)° for [(Bi3O2)(SeO3)2](NO3) and a=8.1489(3) Å, b=9.0663(4) Å, c=7.4729(3) Å, β=114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi3O2)(SeO3)2](NO3) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi3O2)(SeO3)2] 3∞ with NO3- anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO3)](NO3) features 2D bismuth(III) tellurite [Bi(TeO3)2]2∞ layers separated by NO3- anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors.

Non-condensed (oxo)nitridosilicates: La{sub 3}-[SiN{sub 4}]F and the polymorph o-La{sub 3}-[SiN{sub 3}O]O

Energy Technology Data Exchange (ETDEWEB)

Durach, Dajana; Schnick, Wolfgang [Department of Chemistry, Chair in Inorganic Solid-State Chemistry, University of Munich (LMU) (Germany)

2015-08-15

The isotypic compounds La{sub 3}[SiN{sub 4}]F and La{sub 3}[SiN{sub 3}O]O were synthesized in a radio-frequency furnace at 1600 C. The crystal structures [Pnma (no. 62), Z = 4; La{sub 3}(SiN{sub 4})F: a = 9.970(3), b = 7.697(2), c = 6.897(2) Aa, V = 529.3(3) Aa{sup 3}; La{sub 3}(SiON{sub 3})O: a = 9.950(2), b = 7.6160(15), c = 6.9080(14) Aa, V = 523.48(18) Aa{sup 3}] were elucidated from single-crystal X-ray diffraction data and corroborated by Rietveld refinement, lattice-energy calculations (Madelung part of lattice energy, MAPLE) and Raman/FTIR spectroscopy. Both compounds are homeotypic with Na{sub 2}Pr[GeO{sub 4}]OH forming a network of vertex-sharing FLa{sub 6}/OLa{sub 6} octahedra, whose voids are filled with non-condensed SiN{sub 4}/SiN{sub 3}O tetrahedra. o-La{sub 3}[SiON{sub 3}]O is the orthorhombic polymorph of this compound, which probably represents the high-temperature modification, whereas the tetragonal polymorph t-La{sub 3}[SiON{sub 3}]O represents the low-temperature modification. While the space group of the t-polymorph [I4/mcm (no. 140)] differs from the new La{sub 3}[SiN{sub 4}]F and o-La{sub 3}[SiN{sub 3}O]O, the crystal structure contains the same linking pattern. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis of Fe3O4@SiO2@OSi(CH2)3NHRN(CH2PPh2)2PdCl2 type nanocomposite complexes: Highly efficient and magnetically-recoverable catalysts in vitamin K3 synthesis.

Science.gov (United States)

Uruş, Serhan

2016-12-15

The synthesis of aminomethylphosphine-metal complexes have opened a new perspective to the catalytic applications of organic compounds. Magnetic Fe3O4 nano-core was synthesized using the closed quartz tube with Teflon cover and microwaved 200°C for 1h with power controlled instrument set to max. 600W. Novel nano-composite supported; Fe3O4@SiO2(CH2)3NHArN(CH2PPh2)2 and Fe3O4@SiO2(CH2)3N(CH2PPh2)2 type bis(diphenylphosphinomethyl)amino ligands and their Pd(II) complexes have been synthesized and characterized with FT-IR, SEM, EDX, TEM, UV-Visible, XRD and TG/DTA techniques. All the complexes were used as heterogeneous catalysts in the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1, 4-naphthoquinone (vitamin K3, menadione, 2MNQ) in the presence of hydrogen peroxide and acetic acid. Selectivity reached about 55-60% with a conversion of 90-96% using the nano-magnetite supported aminomethylphosphine-Pd(II) complexes. The complexes were very active in three times in the catalytic recycling experiments in five catalytic cycles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hexa-μ-acetato-1:2κ4O,O′;1:2κ2O:O;2:3κ4O,O′;2:3κ2O:O-bis(4,4′-dimethyl-2,2′-bipyridine-1κ2N,N′;3κ2N,N′-2-calcium-1,3-dizinc

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Md. Alamgir Hossain

2013-12-01

Full Text Available In the centrosymmetric trinuclear ZnII...CaII...ZnII title complex, [CaZn2(CH3COO6(C12H12N22], the CaII ion lies on an inversion centre and is octahedrally coordinated by six acetate O atoms. The ZnII ion is coordinated by two N atoms from a bidentate dimethylbipyridine ligand and three O atoms from acetate ligands bridging to the CaII ion, leading to a distorted square-pyramidal coordination sphere. The Zn...Ca distance is 3.4668 (5 Å.

Ab initio studies of O-2(-) (H2O)(n) and O-3(-) (H2O)(n) anionic molecular clusters, n

DEFF Research Database (Denmark)

Bork, Nicolai Christian; Kurten, T.; Enghoff, Martin Andreas Bødker

2011-01-01

that anionic O-2(-)(H2O)n and O-3(-)(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding....... Although clustering up to 12 H2O, we find that the O-2 and O-3 anions retain at least ca. 80 % of the charge and are located at the surface of the cluster. The O-2(-) and O-3(-) speicies are thus accessible for further reactions. We consider the distributions of cluster sizes as function of altitude before...

Raman study of HgBa 2Ca n-1 Cu nO 2 n+2+ δ ( n=1,2,3,4 and 5) superconductors

Science.gov (United States)

Zhou, Xingjiang; Cardona, M.; Chu, C. W.; Lin, Q. M.; Loureiro, S. M.; Marezio, M.

1996-02-01

Polarized micro-Raman scattering measurements have been performed on the five members of the HgBa 2Ca n-1 Cu nO 2 n+2+ δ ( n=1,2,3,4 and 5) high- Tc superconductor family using different laser frequencies. Local laser annealing measurements were carried out to investigate the variation of the Raman spectra with the excess oxygen content, δ. A systematic evolution of the spectra, which display mainly peaks near 590, 570, 540 and 470 cm -1, with increasing number of CuO 2 layers has been observed; its origin has been shown to lie in the variation of the interstitial oxygen content. In addition to confirming that the 590 cm -1 mode represents vibration of apical oxygens in the absence of neighboring excess oxygen, the 570 cm -1 mode, which may be composed of some finer structures, has been assigned to the vibration of the apical oxygen modified by the presence of the neighboring excess oxygens. The 540 and 470 cm -1 modes may represent the direct vibration of excess oxygens. The implication of possible different distribution sites of excess oxygens is discussed. All other observed lower-frequency modes are also assigned.

Crystal structure of the salt bis(triethanolamine-κ4N,O,O′,O′′cadmium bis[2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-ylacetate

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Jamshid Mengnorovich Ashurov

2016-04-01

Full Text Available The reaction of 2-(2-oxo-2,3-dihydro-1,3-benzothiazol-3-ylacetic acid (NBTA and triethanolamine (TEA with Cd(CH3OO2 resulted in the formation of the title salt, [Cd(C6H15NO32](C9H6NO3S2. In its crystal structure, the complex cation [Cd(TEA2]2+ and two independent NBTA− units with essentially similar geometries and conformations are present. In the complex cation, each TEA molecule behaves as an N,O,O′,O′′-tetradentate ligand, giving rise to an eight-coordinate CdII ion with a bicapped trigonal–prismatic configuration. All ethanol groups of each TEA molecule form three five-membered chelate rings around the CdII ion. The Cd—O and Cd—N distances are in the ranges 2.392 (2–2.478 (2 and 2.465 (2–2.475 (3 Å, respectively. O—H...O hydrogen bonds between the TEA hydroxy groups and carboxylate O atoms connect cationic and anionic moieties into chains parallel to [110]. Each NBTA− anion is additionally linked to a symmetry-related anion through π–π stacking interactions between the benzene and thiazoline rings [minimum centroid-to-centroid separation = 3.604 (2 Å]. Together with additional C—H...O interactions, these establish a double-layer polymeric network parallel to (001.

Crystal structure of [Eu(CyMe4-BTBP)2κ2O,O'-(NO3)](NO3)2·n-C8H17OH and its structure in 1-octanol solution.

Science.gov (United States)

Lundberg, Daniel; Persson, Ingmar; Ekberg, Christian

2013-03-21

The structure of the [Eu(CyMe(4)-BTBP)(2)(NO(3))(n)]((3-n)+) complex in 1-octanol solution and solid state has been determined by EXAFS and X-ray crystallography. The crystal structure shows that 1-octanol binds only to the europium(III)-coordinated BTBP molecules through weak van der Waals forces, making it the first indication of the role of the extraction solvent.

Synthesis and crystal structure of new uranyl selenite(IV)-selenate(VI) [C5H14N][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)(HSeO4)

International Nuclear Information System (INIS)

Krivovichev, S.V.; Tananaev, I.G.; Myasoedov, B.F.; Kalenberg, V.

2006-01-01

Crystals of new uranyl selenite(IV)-selenate(VI) [C 5 H 14 N][(UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)](H 2 SeO 3 )(HSeO 4 ) are obtained by the method of evaporation from aqueous solutions. Compound has triclinic lattice, space group P1-bar, a=11.7068(9), b=14.8165(12), c=16.9766(15), α=73.899(6), β=76.221(7), γ=89.361(6) Deg, V=2743.0(4) A 3 , Z=2. Laminated complexes (UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)] 3- are the basis of the structure. [HSe(VI)O 4 ] - , [H 2 Se(IV)O 3 ] complexes and protonated methylbutylamine cations are disposed between layers [ru

Ab initio electron correlated studies on the intracluster reaction of NO+ (H2O)(n) → H3O+ (H2O)(n-2) (HONO) (n = 4 and 5).

Science.gov (United States)

Asada, Toshio; Nagaoka, Masataka; Koseki, Shiro

2011-01-28

Hydrated nitrosonium ion clusters NO(+)(H(2)O)(n) (n = 4 and 5) were investigated by using MP2/aug-cc-pVTZ level of theory to clarify isomeric reaction pathways for formation of HONO and fully hydrated hydride ions. We found some new isomers and transition state structures in each hydration number, whose lowest activation energies of the intracluster reactions were found to be 4.1 and 3.4 kcal mol(-1) for n = 4 and n = 5, respectively. These thermodynamic properties and full quantum mechanical molecular dynamics simulation suggest that product isomers with HONO and fully hydrated hydride ions can be obtained at n = 4 and n = 5 in terms of excess hydration binding energies which can overcome these activation barriers.

Structure of (Ga2O3)2(ZnO)13 and a unified description of the homologous series (Ga2O3)2(ZnO)(2n + 1).

Science.gov (United States)

Michiue, Yuichi; Kimizuka, Noboru; Kanke, Yasushi; Mori, Takao

2012-06-01

The structure of (Ga(2)O(3))(2)(ZnO)(13) has been determined by a single-crystal X-ray diffraction technique. In the monoclinic structure of the space group C2/m with cell parameters a = 19.66 (4), b = 3.2487 (5), c = 27.31 (2) Å, and β = 105.9 (1)°, a unit cell is constructed by combining the halves of the unit cell of Ga(2)O(3)(ZnO)(6) and Ga(2)O(3)(ZnO)(7) in the homologous series Ga(2)O(3)(ZnO)(m). The homologous series (Ga(2)O(3))(2)(ZnO)(2n + 1) is derived and a unified description for structures in the series is presented using the (3+1)-dimensional superspace formalism. The phases are treated as compositely modulated structures consisting of two subsystems. One is constructed by metal ions and another is by O ions. In the (3 + 1)-dimensional model, displacive modulations of ions are described by the asymmetric zigzag function with large amplitudes, which was replaced by a combination of the sawtooth function in refinements. Similarities and differences between the two homologous series (Ga(2)O(3))(2)(ZnO)(2n + 1) and Ga(2)O(3)(ZnO)(m) are clarified in (3 + 1)-dimensional superspace. The validity of the (3 + 1)-dimensional model is confirmed by the refinements of (Ga(2)O(3))(2)(ZnO)(13), while a few complex phenomena in the real structure are taken into account by modifying the model.

Conversion of char nitrogen to N2 under incomplete combustion conditions; Fukanzen nensho jokenka ni okeru char chuchisso no N2 eno tenka

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Q.; Yamauchi, A.; Oshima, Y.; Wu, Z.; Otsuka, Y. [Tohoku University, Sendai (Japan). Institute for Chemical Reaction Science

1996-10-28

The effect of combustion conditions on conversion of char nitrogen to N2 was studied in the combustion experiment of char obtained by pyrolysis of coal. Char specimen was prepared by holding ZN coal of Chinese lignite in Ar atmosphere at 1123K for one hour. A batch scale quartz-made fluidized bed reactor was used for combustion experiment. After the specimen was fluidized in reaction gas, it was rapidly heated to start combustion reaction. CO, CO2 and N2 in produced gases were online measured by gas chromatography (GC). As the experimental result, under the incomplete combustion condition where a large amount of CO was produced by consuming almost all of O2, no NOx and N2O produced from char were found, and almost all of N-containing gas was N2. At the final stage of combustion, pyridinic-N disappeared completely, and pyrrolic-N decreased, while O-containing nitrogen complexes became a main component. It was thus suggested that O-containing nitrogen complexes are playing the role of intermediate product in combustion reaction. 7 refs., 4 figs., 1 tab.

μ-Acetato-κ2O:O′-[7,23-dibenzyl-15,31-dichloro-3,7,11,19,23,27-hexaazatricyclo[27.3.1.113,17]tetratriconta-1(32,2,11,13,15,17(34,18,27,29(33,30-decaene-33,34-diolato-κ10N4,N5,N6,O1,O2:N1,N2,N3,O1,O2]dinickel(II perchlorate acetonitrile disolvate

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Juan Kong

2008-01-01

Full Text Available The title complex, [Ni2(C42H46Cl2N6O2(C2H3O2]ClO4·2CH3CN, was synthesized by condensation of 2,6-diformyl-4-chlorophenol with N,N-bis(aminopropylbenzylamine in the presence of NiII ions. The ligand is a 28-membered macrocycle with two identical pendant arms. The coordination geometries of the Ni atoms are both octahedral. The two Ni atoms are bridged by two phenolate O atoms of the macrocyclic ligand and one acetate ligand, with an Ni...Ni distance of 3.147 (4 Å.

Carbonyl[4-(2,3-dimethylphenylaminopent-3-en-2-onato-κ2N,O](triphenylphosphine-κPrhodium(I

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Gertruida J. S. Venter

2009-11-01

Full Text Available In the title compound, [Rh(C13H16NO(C18H15P(CO], the coordination geometry of the RhI atom is square-planar, formed by the coordinating N and O atoms of the bidentate enaminoketonate ligand, one C atom from the carbonyl group and a P atom from triphenylphosphine. The complex displays a 0.591 (3:0.409 (3 ratio disorder of the phenyl unit of the monoanionic N,O-bidentate ligand. Intramolecular hydrogen bonding is observed between a C—H group of the triphenylphosphine unit and the O atom of the enaminoketonate ligand.

Bis(acetylacetonato-κ2O,O′(2-amino-1-methyl-1H-benzimidazole-κN3oxidovanadium(IV

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Zukhra Ch. Kadirova

2009-07-01

Full Text Available The title mixed-ligand oxidovanadium(IV compound, [VO(C5H7O22(C8H9N3], contains a VIV atom in a distorted octahedral coordination, which is typical for such complexes. The vanadyl group and the N-heterocyclic ligand are cis to each other. The coordination bond is located at the endocyclic N atom of the benzimidazole ligand. Intramolecular hydrogen bonds between the exo-NH2 group H atoms and acetylacetonate O atoms stabilize the crystal structure.

Extended networks, porous sheets, and chiral frameworks. Thorium materials containing mixed geometry anions: Structures and properties of Th(SeO3)(SeO4), Th(IO3)2(SeO4)(H2O)3.H2O, and Th(CrO4)(IO3)2

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Sullens, Tyler A.; Almond, Philip M.; Byrd, Jessica A.; Beitz, James V.; Bray, Travis H.; Albrecht-Schmitt, Thomas E.

2006-01-01

Three novel Th(IV) compounds containing heavy oxoanions, Th(SeO 3 )(SeO 4 ) (1), Th(IO 3 ) 2 (SeO 4 )(H 2 O) 3 .H 2 O (2), and Th(CrO 4 )(IO 3 ) 2 (3), have been synthesized under mild hydrothermal conditions. Each of these three distinct structures contain trigonal pyramidal and tetrahedral oxoanions. Compound 1 adopts a three-dimensional structure formed from ThO 9 tricapped trigonal prisms, trigonal pyramidal selenite, SeO 3 2- , anions containing Se(IV), and tetrahedral selenate, SeO 4 2- , anions containing Se(VI). The structure of 2 contains two-dimensional porous sheets and occluded water molecules. The Th centers are found as isolated ThO 9 tricapped trigonal prisms and are bound by four trigonal pyramidal iodate anions, two tetrahedral selenate anions, and three coordinating water molecules. In the structure of 3, the Th(IV) cations are found as ThO 9 tricapped trigonal prisms. Each Th center is bound by six IO 3 1- anions and three CrO 4 2- anions forming a chiral three-dimensional structure. Second-harmonic generation of 532nm light from 1064nm radiation by a polycrystalline sample of 3 was observed. Crystallographic data (193K, MoKα, λ=0.71073): 1; monoclinic, P2 1 /c; a=7.0351(5)A, b=9.5259(7)A, c=9.0266(7)A, β=103.128(1), Z=4, R(F)=2.47% for 91 parameters with 1462 reflections with I>2σ(I); 2, monoclinic, P2 1 /n, a=7.4889(9)A, b=8.002(1)A, c=20.165(3)A, β=100.142(2), Z=4, R(F)=4.71% for 158 parameters with 2934 reflections with I>2σ(I); 3, orthorhombic, P2 1 2 1 2 1 , a=7.3672(5)A, b=9.3617(6)A, c=11.9201(7)A, Z=4, R(F)=2.04% for 129 parameters with 2035 reflections with I>2σ(I)

Cr6+-containing phases in the system CaO-Al2O3-CrO42--H2O at 23 °C

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Pöllmann, Herbert; Auer, Stephan

2012-01-01

Synthesis and investigation of lamellar calcium aluminium hydroxy salts was performed to study the incorporation of chromate ions in the interlayer of lamellar calcium aluminium hydroxy salts. Different AFm-phases (calcium aluminate hydrate with alumina, ferric oxide, mono-anion phase) containing chromate were synthesized. These AFm-phases belong to the group of layered double hydroxides (LDHs). 3CaO·Al2O3·CaCrO4·nH2O and C3A·1/2Ca(OH)2·1/2CaCrO4·12H2O were obtained as pure phases and their different distinct interlayer water contents and properties determined. Solid solution of chromate-containing phases and tetracalcium-aluminate-hydrate (TCAH) were studied. The uptake of chromate into TCAH from solutions was proven. Chromate contents in solution decrease to <0.2 mg/l.

Effect of the thin Ga2O3 layer in n+-ZnO/n-Ga2O3/p-Cu2O heterojunction solar cells

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Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro

2013-01-01

The influence of inserting a Ga 2 O 3 thin film as an n-type semiconductor layer on the obtainable photovoltaic properties in Cu 2 O-based heterojunction solar cells was investigated with a transparent conductive Al-doped ZnO (AZO) thin film/n-Ga 2 O 3 thin film/p-Cu 2 O sheet structure. It was found that this Ga 2 O 3 thin film can greatly improve the performance of Cu 2 O-based heterojunction solar cells fabricated using polycrystalline Cu 2 O sheets that had been prepared by a thermal oxidization of copper sheets. The obtained photovoltaic properties in the AZO/Ga 2 O 3 /Cu 2 O heterojunction solar cells were strongly dependent on the deposition conditions of the Ga 2 O 3 films. The external quantum efficiency obtained in AZO/Ga 2 O 3 /Cu 2 O heterojunction solar cells was found to be greater at wavelengths below approximately 500 nm than that obtained in AZO/Cu 2 O heterojunction solar cells (i.e., prepared without a Ga 2 O 3 layer) at equivalent wavelengths. This improvement of photovoltaic properties is mainly attributed to a decrease in the level of defects at the interface between the Ga 2 O 3 thin film and the Cu 2 O sheet. Conversion efficiencies over 5% were obtained in AZO/Ga 2 O 3 /Cu 2 O heterojunction solar cells fabricated using an n-Ga 2 O 3 thin-film layer prepared with a thickness of 40–80 nm at an O 2 gas pressure of approximately 1.7 Pa by a pulsed laser deposition. - Highlights: • We demonstrate high-efficiency Cu 2 O-based p-n heterojunction solar cells. • A non-doped Ga 2 O 3 thin film was used as an n-type semiconductor layer. • The Ga 2 O 3 thin film was prepared at a low temperature by a low damage deposition. • p-type Cu 2 O sheets prepared by thermal oxidization of copper sheets were used. • Conversion efficiencies over 5% were obtained in AZO/n-Ga 2 O 3 /p-Cu 2 O solar cells

Methanesulfonates of high-valent metals. Syntheses and structural features of MoO_2(CH_3SO_3)_2, UO_2(CH_3SO_3)_2, ReO_3(CH_3SO_3), VO(CH_3SO_3)_2, and V_2O_3(CH_3SO_3)_4 and their thermal decomposition under N_2 and O_2 atmosphere

International Nuclear Information System (INIS)

Betke, Ulf; Neuschulz, Kai; Wickleder, Mathias S.

2011-01-01

Oxide methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO_3, UO_2(CH_3COO)_2.2 H_2O, Re_2O_7(H_2O)_2, and V_2O_5 with CH_3SO_3H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide methanesulfonates of these elements. MoO_2(CH_3SO_3)_2 (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm"3, Z=8) contains [MoO_2] moieties connected by [CH_3SO_3] ions to form layers parallel to (100). UO_2(CH_3SO_3)_2 (P2_1/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1) "c"i"r"c"l"e, V=1.8937(3) nm"3, Z=8) consists of linear UO_2"2"+ ions coordinated by five [CH_3SO_3] ions, forming a layer structure. VO(CH_3SO_3)_2 (P2_1/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1) "c"i"r"c"l"e, V=0.8290(2) nm"3, Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO_3(CH_3SO_3) (P anti 1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2) "c"i"r"c"l"e, V=1.1523(4) nm"3, Z=8) a chain structure exhibiting infinite O-[ReO_2]-O-[ReO_2]-O chains is formed. Each [ReO_2]-O-[ReO_2] unit is coordinated by two bidentate [CH_3SO_3] ions. V_2O_3(CH_3SO_3)_4 (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm"3, Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH_3SO_3] ligands. Additional methanesulfonate ions connect the [V_2O_3] groups along [001]. Thermal decomposition of the compounds was monitored under N_2 and O_2 atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N_2 the decomposition proceeds with reduction of the metal leading to the oxides MoO_2, U_3O_7, V_4O_7, and VO_2; for MoO_2(CH_3SO_3)_2, a small amount of MoS_2 is formed. If the thermal decomposition is carried out in a atmosphere of O_2 the oxides MoO_3 and V_2O_5 are formed. (Copyright copyright 2011 WILEY-VCH Verlag

Ammonia oxidation pathways and nitrifier denitrification are significant sources of N2O and NO under low oxygen availability.

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Zhu, Xia; Burger, Martin; Doane, Timothy A; Horwath, William R

2013-04-16

The continuous increase of nitrous oxide (N2O) abundance in the atmosphere is a global concern. Multiple pathways of N2O production occur in soil, but their significance and dependence on oxygen (O2) availability and nitrogen (N) fertilizer source are poorly understood. We examined N2O and nitric oxide (NO) production under 21%, 3%, 1%, 0.5%, and 0% (vol/vol) O2 concentrations following urea or ammonium sulfate [(NH4)2SO4] additions in loam, clay loam, and sandy loam soils that also contained ample nitrate. The contribution of the ammonia (NH3) oxidation pathways (nitrifier nitrification, nitrifier denitrification, and nitrification-coupled denitrification) and heterotrophic denitrification (HD) to N2O production was determined in 36-h incubations in microcosms by (15)N-(18)O isotope and NH3 oxidation inhibition (by 0.01% acetylene) methods. Nitrous oxide and NO production via NH3 oxidation pathways increased as O2 concentrations decreased from 21% to 0.5%. At low (0.5% and 3%) O2 concentrations, nitrifier denitrification contributed between 34% and 66%, and HD between 34% and 50% of total N2O production. Heterotrophic denitrification was responsible for all N2O production at 0% O2. Nitrifier denitrification was the main source of N2O production from ammonical fertilizer under low O2 concentrations with urea producing more N2O than (NH4)2SO4 additions. These findings challenge established thought attributing N2O emissions from soils with high water content to HD due to presumably low O2 availability. Our results imply that management practices that increase soil aeration, e.g., reducing compaction and enhancing soil structure, together with careful selection of fertilizer sources and/or nitrification inhibitors, could decrease N2O production in agricultural soils.

Bis[μ-2,5-bis(pyridin-2-yl-1,3,4-thiadiazole-κ4N2,N3:N4,N5]bis[(nitrato-κOsilver(I] tetrahydrate

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Abdelhakim Laachir

2013-06-01

Full Text Available The self-assembly of an angular 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole ligand (L with silver nitrate (AgNO3 produced a new dinuclear silver(I coordination complex, [Ag2(C12H8N4S2(NO32]·4H2O, which crystallizes with two Ag atoms bridged by two L ligands. The Ag atom is surrounded by four N atoms of L and by one O from the nitrate anion defining a distorted square pyramid. The atoms comprising the dication are nearly coplanar, with an r.m.s. deviation of 0.1997 Å. Molecules are linked by C—H...O and O—H...O hydrogen bonds through nitrate anions and water molecules, forming a two-dimensional porous network. The overall structure involves stacking of Ag complex layers along the b axis. The cohesion in the three-dimensional architecture is ensured by O...Ag interactions.

(3-Methylbenzonitrile-1κN-cis-tetrakis(μ-N-phenylacetamidato-1:2κ4N:O;1:2κ4O:N-dirhodium(II(Rh—Rh

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Cassandra T. Eagle

2014-08-01

Full Text Available The complex molecule of the title compound, [Rh2{N(C6H5COCH3}4(NCC7H7], has crystallographically-imposed mirror symmetry. The four acetamide ligands bridging the dirhodium core are arranged in a 2,2-cis manner with two N atoms and two O atoms coordinating to the unique RhII atom cis to one another. The Neq—Rh—Rh—Oeq torsion angles on the acetamide bridge are 0.75 (7 and 1.99 (9°. The axial nitrile ligand completes the distorted octahedral coordination sphere of one RhII atom and shows a nonlinear coordination, with an Rh—N—C bond angle of 162.8 (5°; the N—C bond length is 1.154 (7 Å.

Synthesis and crystal structures of nitratocobaltates Na2[Co(NO3)4], K2[Co(NO3)4], and Ag[Co(NO3)3] and potassium nitratonickelate K2[Ni(NO3)4

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Morozov, I. V.; Fedorova, A. A.; Albov, D. V.; Kuznetsova, N. R.; Romanov, I. A.; Rybakov, V. B.; Troyanov, S. I.

2008-01-01

The cobalt(II) and nickel(II) nitrate complexes with an island structure (Na 2 [Co(NO 3 ) 4 ] (I) and K 2 [Co(NO 3 ) 4 ] (II)] and a chain structure [Ag[Co(NO 3 ) 3 ] (III) and K 2 [Ni(NO 3 ) 4 ] (IV)] are synthesized and investigated using X-ray diffraction. In the anionic complex [Co(NO 3 ) 4 ] 2− of the crystal structure of compound I, the Co coordination polyhedron is a twisted tetragonal prism formed by the O atoms of four asymmetric bidentate nitrate groups. In the anion [Co(NO 3 ) 4 ] 2− of the crystal structure of compound II, one of the four NO 3 groups is monodentate and the other NO 3 groups are bidentate (the coordination number of the cobalt atom is equal to seven, and the cobalt coordination polyhedron is a monocapped trigonal prism). The crystal structures of compounds III and IV contain infinite chains of the compositions [Co(NO 3 ) 2 (NO 3 ) 2/2 ] − and [Ni(NO 3 ) 3 (NO 3 ) 2/2 ] 2− , respectively. In the crystal structure of compound III, seven oxygen atoms of one monodentate and three bidentate nitrate groups form a dodecahedron with an unoccupied vertex of the A type around the Co atom. In the crystal structure of compound IV, the octahedral polyhedron of the Ni atom is formed by five nitrate groups, one of which is terminal bidentate. The data on the structure of Co(II) coordination polyhedra in the known nitratocobaltates are generalized.

Synthesis and crystal structures of nitratocobaltates Na2[Co(NO3)4], K2[Co(NO3)4], and Ag[Co(NO3)3] and potassium nitratonickelate K2[Ni(NO3)4

International Nuclear Information System (INIS)

Morozov, I. V.; Fedorova, A. A.; Albov, D. V.; Kuznetsova, N. R.; Romanov, I. A.; Rybakov, V. B.; Troyanov, S. I.

2008-01-01

The cobalt(II) and nickel(II) nitrate complexes with an island structure (Na 2 [Co(NO 3 ) 4 ] (I) and K 2 [Co(NO 3 ) 4 ] (II)] and a chain structure [Ag[Co(NO 3 ) 3 ] (III) and K 2 [Ni(NO 3 ) 4 ] (IV)] are synthesized and investigated using X-ray diffraction. In the anionic complex [Co(NO 3 ) 4 ] 2- of the crystal structure of compound I, the Co coordination polyhedron is a twisted tetragonal prism formed by the O atoms of four asymmetric bidentate nitrate groups. In the anion [Co(NO 3 ) 4 ] 2- of the crystal structure of compound II, one of the four NO 3 groups is monodentate and the other NO 3 groups are bidentate (the coordination number of the cobalt atom is equal to seven, and the cobalt coordination polyhedron is a monocapped trigonal prism). The crystal structures of compounds III and IV contain infinite chains of the compositions [Co(NO 3 ) 2 (NO 3 ) 2/2 ] - and [Ni(NO 3 ) 3 (NO 3 ) 2/2 ] 2- , respectively. In the crystal structure of compound III, seven oxygen atoms of one monodentate and three bidentate nitrate groups form a dodecahedron with an unoccupied vertex of the A type around the Co atom. In the crystal structure of compound IV, the octahedral polyhedron of the Ni atom is formed by five nitrate groups, one of which is terminal bidentate. The data on the structure of Co(II) coordination polyhedra in the known nitratocobaltates are generalized

Antimicrobial activity study of a μ3-oxo bridged [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2] cluster

Science.gov (United States)

Pathak, Sayantan; Jana, Barun; Mandal, Manab; Mandal, Vivekananda; Ghorai, Tanmay K.

2017-11-01

Synthesis, characterization and antimicrobial activity of a tri-nuclear μ3-Oxobridged Fe(III) cluster [Fe3O(PhCO2)6(MeOH)3](NO3)(MeOH)2(1) is reported. Cluster 1 is synthesized in a single pot reaction among Fe(NO3)3·9H2O, C6H5COOH, NaN3 (1:4:1) in MeOH. Single crystal X-ray diffraction studies of the isolated crystals show that it is μ3-Oxo bridged trimeric assembly of three Fe atoms via bridging benzoate anions. Furthermore, BVS calculations show that all three Fe atoms in complex 1 are in +3 oxidation state and are surrounded by benzoate anions and methanol in octahedral environment. The oxidation state of iron is also confirmed from the cyclic voltamogram. FT-IR spectroscopy and CHN analysis of the isolated crystals further supports the functional group attached to the periphery of the complex. The nanomolecular size of complex 1 is 1.29 nm. The antimicrobial efficiency studies of the complex 1 show significant inhibition of the growth of the organisms, viz. B. cereus MTCC 1272, S. epidermidis MTCC 3086 and S. typhimurium MTCC 98 and produced 23 ± 1.93 mm, 16 ± 1.77 mm and 12 ± 2.42 mm inhibition zones respectively. However, it shows zero inhibition to the strain of E. coli MTCC 723.

Bis(2,3,5,6-tetra-2-pyridylpyrazine-κ3N2,N1,N6iron(II bis(dicyanamidate 4.5-hydrate

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R. Cortés

2010-03-01

Full Text Available In the title compound, [Fe(C24H16N62][N(CN2]2·4.5H2O, the central iron(II ion is hexacoordinated by six N atoms of two tridentate 2,3,5,6-tetra-2-pyridylpyrazine (tppz ligands. Two dicyanamide anions [dca or N(CN2−] act as counter-ions, and 4.5 water molecules act as solvation agents. The structure contains isolated cationic iron(II–tppz complexes and the final neutrality is obtained with the two dicyanamide anions. One of the dicyanamide anions and a water molecule are disordered with an occupancy ratio of 0.614 (8:0.386 (8. O—H...O, O—H...N and C—H...O hydrogen bonds involving dca, water and tppz molecules are observed.

Bisamidate and Mixed Amine/Amidate NiN2S2 Complexes as Models for Nickel-Containing Acetyl Coenzyme A Synthase and Superoxide Dismutase: An Experimental and Computational Study

International Nuclear Information System (INIS)

Mathrubootham, V.; Thomas, J.; Staples, R.; McCraken, J.; Shearer, J.; Hegg, E.

2010-01-01

The distal nickel site of acetyl-CoA synthase (Ni d -ACS) and reduced nickel superoxide dismutase (Ni-SOD) display similar square-planar Ni II N 2 S 2 coordination environments. One difference between these two sites, however, is that the nickel ion in Ni-SOD contains a mixed amine/amidate coordination motif while the Ni d site in Ni-ACS contains a bisamidate coordination motif. To provide insight into the consequences of the different coordination environments on the properties of the Ni ions, we systematically examined two square-planar Ni II N 2 S 2 complexes, one with bisthiolate-bisamidate ligation (Et 4 N) 2 (Ni(L1))·2H 2 O (2) (H 4 L1 = N-(2-mercaptoacetyl)-N(prime)-(2-mercaptoethyl)glycinamide) and another with bisthiolate-amine/amidate ligation K(Ni(HL2)) (3) (H 4 L2 = N-(2(double p rime)-mercaptoethyl)-2- ((2(prime)-mercaptoethyl)amino)acetamide). Although these two complexes differ only by a single amine versus amidate ligand, their chemical properties are quite different. The stronger in-plane ligand field in the bisamidate complex (Ni II (L1)) 2- (2) results in an increase in the energies of the d → d transitions and a considerably more negative oxidation potential. Furthermore, while the bisamidate complex (Ni II (L1)) 2- (2) readily forms a trinuclear species (Et 4 N) 2 ({Ni(L1)} 2 Ni)·H 2 O (1) and reacts rapidly with O 2 , presumably via sulfoxidation, the mixed amine/amidate complex (Ni II (HL2)) - (3) remains monomeric and is stable for days in air. Interestingly, the Ni III species of the bisamidate complex formed by chemical oxidation with I 2 can be detected by electron paramagnetic resonance (EPR) spectroscopy while the mixed amine/amidate complex immediately decomposes upon oxidation. To explain these experimentally observed properties, we performed S K-edge X-ray absorption spectroscopy and low-temperature (77 K) electronic absorption measurements as well as both hybrid density functional theory (hybrid-DFT) and spectroscopy oriented

Synthesis, crystal structures, and characterization of double complex salts [Au(en)2][Rh(NO2)6]·2H2O and [Au(en)2][Rh(NO2)6

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Plyusnin, Pavel E.; Makotchenko, Evgenia V.; Shubin, Yury V.; Baidina, Iraida A.; Korolkov, Ilya V.; Sheludyakova, Liliya A.; Korenev, Sergey V.

2015-11-01

Double complex salts of rhodium(III) and gold(III) of the composition [Au(en)2][Rh(NO2)6]·2H2O (1) and [Au(en)2][Rh(NO2)6] (2) have been prepared. Crystal structures of the compounds have been determined by single crystal X-ray diffraction. The compounds have been characterized by PXRD, IR, far-IR, CHN and DTA. The complexes have a layered structures. The presence of water in 1 makes the structure of the hydrated DCS less dense as compared to the anhydrous one. The environment of the cation and the anion in the two structures is the same, oxygen atoms of the nitro groups are involved in hydrogen bonds N-H⋯O, N⋯O distances being approximately the same. The structures of 1 and 2 are notable in having shortened contacts between the gold atoms and the oxygen atoms of the nitro groups of the neighboring complex anions. The thermal behavior of the complexes in a hydrogen atmosphere was investigated. The final product of thermolysis prepared at the temperature 600°C is a two-phase mixture of pure metallic gold and the solid solution Rh0.93Au0.07.

Bis{(E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium} bis[μ-(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamido(2−]bis{[(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide]copper(II} bis((E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate acetonitrile disolvate

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Andrii I. Buvailo

2012-12-01

Full Text Available The reaction between copper(II nitrate and (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide led to the formation of the dinuclear centrosymmetric copper(II title complex, (C8H18N3O22[Cu2(C8H15N3O22(C8H17N3O22](C9H16N3O42·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O22(C8H17N3O22] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu...Cu separation = 4.0608 (5 Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex molecule co-crystallizes with two molecules of acetonitrile, two molecules of the protonated ligand (E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium and two negatively charged (E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate anions, which were probably formed as a result of condensation between (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide and hydrogencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O22(C8H17N3O22] and the ion pair C8H18N3O2+.C9H16N3O4− are connected via an extended system of hydrogen bonds.

Chirality in distorted square planar Pd(O,N)2 compounds.

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Brunner, Henri; Bodensteiner, Michael; Tsuno, Takashi

2013-10-01

Salicylidenimine palladium(II) complexes trans-Pd(O,N)2 adopt step and bowl arrangements. A stereochemical analysis subdivides 52 compounds into 41 step and 11 bowl types. Step complexes with chiral N-substituents and all the bowl complexes induce chiral distortions in the square planar system, resulting in Δ/Λ configuration of the Pd(O,N)2 unit. In complexes with enantiomerically pure N-substituents ligand chirality entails a specific square chirality and only one diastereomer assembles in the lattice. Dimeric Pd(O,N)2 complexes with bridging N-substituents in trans-arrangement are inherently chiral. For dimers different chirality patterns for the Pd(O,N)2 square are observed. The crystals contain racemates of enantiomers. In complex two independent molecules form a tight pair. The (RC) configuration of the ligand induces the same Δ chirality in the Pd(O,N)2 units of both molecules with varying square chirality due to the different crystallographic location of the independent molecules. In complexes and atrop isomerism induces specific configurations in the Pd(O,N)2 bowl systems. The square chirality is largest for complex [(Diop)Rh(PPh3 )Cl)], a catalyst for enantioselective hydrogenation. In the lattice of two diastereomers with the same (RC ,RC) configuration in the ligand Diop but opposite Δ and Λ square configurations co-crystallize, a rare phenomenon in stereochemistry. © 2013 Wiley Periodicals, Inc.

Comparative study of silicate glasses containing Bi2O3, PbO and BaO: Radiation shielding and optical properties

International Nuclear Information System (INIS)

Kirdsiri, K.; Kaewkhao, J.; Chanthima, N.; Limsuwan, P.

2011-01-01

Research highlights: → We change Bi 2 O 3 , PbO and BaO concentration in silicate glasses. → The densities of Bi 2 O 3 glasses more than PbO glasses and BaO glasses. → The Um of Bi 2 O 3 glasses and PbO glasses are comparable and more than BaO glasses. → This suggests that Bi 2 O 3 can replace PbO in radiation shielding glasses. - Abstract: The radiation shielding and optical properties of xBi 2 O 3 :(100-x)SiO 2 , xPbO:(100-x)SiO 2 and xBaO:(100-x)SiO 2 glass systems (where 30 ≤ x ≤ 70 is the composition by weight%) have been investigated. Total mass attenuation coefficients (μ m ) of glasses at 662 keV were improved by increasing their Bi 2 O 3 and PbO content, which raised the photoelectric absorption in glass matrices. Raising the BaO content to the same fraction range, however, brought no significant change to μ m . These results indicate that photon is strongly attenuated in Bi 2 O 3 and PbO containing glasses, and but not in BaO containing glass. The results from the optical absorption spectra show an edge that was not sharply defined; clearly indicating the amorphous nature of glass samples. It is observed that the cutoff wavelength for Bi 2 O 3 containing glass was longer than PbO and BaO containing glasses.

(μ-3-Acetyl-5-carboxyl­ato-4-methyl­pyrazolido-1:2κ4 N 2,O 3:N 1,O 5)-μ-chlorido-tetra­pyridine-1κ2 N,2κ2 N-chlorido-1κCl-dicopper(II) propan-2-ol solvate

Science.gov (United States)

Malinkin, Sergey; Penkova, Larisa; Pavlenko, Vadim A.; Haukka, Matti; Fritsky, Igor O.

2009-01-01

The title compound, [Cu2(C7H6N2O3)Cl2(C5H5N)4]·C3H8O, is a binuclear pyrazolate complex, in which the two CuII atoms have different coordination numbers and are connected by a bridging Cl atom. One CuII atom has a distorted square-pyramidal coordination environment formed by two pyridine N atoms, one bridging Cl atom and an N,O-chelating pyrazolate ligand. The other CuII atom adopts an octa­hedral geometry defined by two pyridine N atoms at the axial positions, two Cl atoms and the coordinated pyrazolate ligand in the equatorial plane. An O—H⋯O hydrogen bond connects the complex mol­ecules and propan-2-ol solvent mol­ecules into pairs. These pairs form columns along the a axis. PMID:21577764

Synthesis and crystal structure of Na6[(UO2)3O(OH)3(SeO4)2]2·10H2O

International Nuclear Information System (INIS)

Baeva, E.Eh.; Serezhkina, L.B.; Virovets, A.V.; Peresypkina, E.V.

2006-01-01

The complex Na 6 [(UO 2 ) 3 O(OH) 3 (SeO 4 ) 2 ] 2 ·10H 2 O (I) is synthesized and studied by monocrystal X-ray diffraction. The compound crystallizes in the orthorhombic crystal system with the unit cell parameters: a=14.2225(7) A, b=18.3601(7) A, c=16.5406(6) A, V=4319.2(3) A 3, Z=4, space group Cmcm, R 1 =0.0406. Compound I is found to be a representative of the crystal-chemical group A 3 M 3 M 3 2 T 2 3 (A=UO 2 2+ , M 3 =O 2- , M 2 =OH - , T 3 =SeO 4 2- ) of the uranyl complexes; it contains layer uranium-containing groups [(UO 2 ) 3 O(OH) 3 (SeO 4 ) 2 ] 3- . These layers are linked to form a three-dimensional cage through bonds formed by the sodium atoms with the oxygen atoms of the uranyl ions and SeO 4 groups that belong to different layers [ru

Solubility Modeling of the Binary Systems Fe(NO3)3–H2O, Co(NO3)2–H2O and the Ternary System Fe(NO3)3–Co(NO3)2–H2O with the Extended Universal Quasichemical (UNIQUAC) Model

DEFF Research Database (Denmark)

Arrad, Mouad; Kaddami, Mohammed; Goundali, Bahija El

2016-01-01

Solubility modeling in the binary system Fe(NO3)3–H2O, Co(NO3)2–H2O and the ternary system Fe(NO3)3–Co(NO3)2–H2O is presented. The extended UNIQUAC model was applied to the thermodynamic assessment of the investigated systems. The model parameters obtained were regressed simultaneously using...... the available databank but with more experimental points, recently published in the open literature. A revision of previously published parameters for the cobalt ion and new parameters for the iron(III) nitrate system are presented. Based on this set of parameters, the equilibrium constants of hydrates...

Investigation of nitrous oxide (N2O) abatement technologies. 2; Asanka chisso (N2O) no teigen taisaku ni kansuru chosa. 2

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Emission amount of nitrous oxide (N2O) from anthropogenic sources is analyzed, and reduction effects by the abatement technologies are evaluated. The concentration of nitrous oxide in the atmosphere continues to increase and emissions from agricultural and ecosystem sources are drawing particular attention. For the emission of N2O in Japan, 8.28 Gg-N2O per year is emitted from fossil fuel combustion facilities, 6.95 from waste incineration facilities, 22.5 from transportation vehicles including automobiles, 26.7 from the chemical industry including establishments engaged in adipic acid production, 2.1 from sewage treatment facilities including septic tanks, 6.3 from farmland, and 7.1 from livestock excrement. For the N2O abatement technologies for different sources, fuel improvement, high temperature combustion, acceleration of reduction decomposition reaction, and development of catalysts are significant for the combustion technologies. In connection with N2O discharged in the process of adipic acid production, major businesses have internationally committed to up to 99% abatement of the N2O emissions by 1998. With regard to wastewater and sewage treatment facilities and septic tanks, improvement in COD/NO-N ratio, retention period, pH level, and reduction process is pointed out. 204 refs., 70 figs., 53 tabs.

Magnetic properties of Aurivillius lanthanide-bismuth (LnFeO3nBi4Ti3O12 (n = 1,2 layered titanates

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Tartaj, J.

2008-06-01

Full Text Available Bismuth titanates of Aurivillius layer-structure (BiFeO3nBi4Ti3O12, are of great technological interest because of their applications as non-volatile ferroelectric memories and high-temperature piezoelectric materials. The synthesis and crystallographic characterization of a new family of compounds (LnFeO3nBi4Ti3O12 was recently reported, in which the layers consist of LnFeO3 perovskites with a lanthanide Ln3+ substituting diamagnetic Bi3+. We report herein the magnetic properties of bulk samples, with Ln = Nd, Eu, Gd and Tb, and n = 1 and 2. Single-layer materials are paramagnetic, similar to non-substituted bismuth titanate Bi5FeTi3O15, and show crystal field effects due to the crystallographic environment of Eu3+ and Tb3+. Several anomalies are detected in the magnetization M(T of double-layer (LnFeO32Bi4Ti3O12 compounds, related to the strong magnetism of Tb and Gd, since they weakly appear for Nd and they are absent in the VanVleck Eu3+ ion and in the parent Bi6Fe2Ti3O18 compound.Los titanatos de hierro y bismuto con estructura laminar tipo Aurivillius, (BiFeO3nBi4Ti3O12, tienen un gran interés tecnológico debido a sus aplicaciones como memorias ferroeléctricas no volátiles y como piezoeléctrico cerámico de alta temperatura. La síntesis y la caracterización cristalina de una nueva familia de compuestos (LnFeO3nBi4Ti3O12 han sido recientemente reportadas, en la que el catión diamagnético Bi3+ ha sido sustituido por los paramagnéticos Ln3+ en los bloques de perovskita. Se estudian las propiedades magnéticas de muestras cerámicas en volumen con Ln = Nd, Eu, Gd y Tb, y n = 1 y 2. Los materiales con n=1 son paramagnéticos y similares al no sustituido Bi5FeTi3O15, y muestran efectos de campo cristalino debido al entorno cristalino de Eu3+ y Tb3+. Se han detectado algunas anomalías en la magnetización M(T de los compuestos n=2 (LnFeO32Bi4Ti3O12 que están relacionadas con el fuerte magnetismo de Tb y Gd, que aparecen d

A consilience model to describe N2O production during biological N removal

DEFF Research Database (Denmark)

Domingo Felez, Carlos; Smets, Barth F.

2016-01-01

Nitrous oxide (N2O), a potent greenhouse gas, is produced during biological nitrogen conversion in wastewater treatment operations. Complex mechanisms underlie N2O production by autotrophic and heterotrophic organisms, which continue to be unravelled. Mathematical models that describe nitric oxide...... (NO) and N2O dynamics have been proposed. Here, a first comprehensive model that considers all relevant NO and N2O production and consumption mechanisms is proposed. The model describes autotrophic NO production by ammonia oxidizing bacteria associated with ammonia oxidation and with nitrite reduction......, followed by NO reduction to N2O. It also considers NO and N2O as intermediates in heterotrophic denitrification in a 4-step model. Three biological NO and N2O production pathways are accounted for, improving the capabilities of existing models while not increasing their complexity. Abiotic contributions...

Haloacyl complexes of boron, [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br, I).

Science.gov (United States)

Finze, Maik; Bernhardt, Eduard; Willner, Helge; Lehmann, Christian W

2005-11-04

The haloacyltris(trifluoromethyl)borate anions [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br, I) have been synthesized by reacting (CF3)3BCO with either MHal (M=K, Cs; Hal=F) in SO2 or MHal (M=[nBu4N]+, [Et4N]+, [Ph4P]+; Hal=Cl, Br, I) in dichloromethane. Metathesis reactions of the fluoroacyl complex with Me3SiHal (Hal=Cl, Br, I) led to the formation of its higher homologues. The thermal stabilities of the haloacyltris(trifluoromethyl)borates decrease from the fluorine to the iodine derivative. The chemical reactivities decrease in the same order as demonstrated by a series of selected reactions. The new [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br) salts are used as starting materials in the syntheses of novel compounds that contain the (CF3)3B-C fragment. All borate anions [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br, I) have been characterized by multinuclear NMR spectroscopy (11B, 13C, 17O, 19F) and vibrational spectroscopy. [PPh4][(CF3)3BC(O)Br] crystallizes in the monoclinic space group P2/c (no. 13) and the bond parameters are compared with those of (CF3)3BCO and K[(CF3)3BC(O)F]. The interpretation of the spectroscopic and structural data are supported by DFT calculations [B3LYP/6-311+G(d)].

Aqua{2-(pyridin-2-yl-N-[(pyridin-2-ylmethylidene]ethanamine-κ3N,N′,N′′}(sulfato-κ2O,O′copper(II tetrahydrate

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Daniel Tinguiano

2013-01-01

Full Text Available The title complex, [Cu(SO4(C13H13N3(H2O]·4H2O, was obtained by mixing copper sulfate pentahydrate and 2-(pyridin-2-yl-N-(pyridin-2-ylmethylideneethanamine in ethanol under reflux conditions. The CuII ion shows a Jahn–Teller-distorted octahedral geometry, with equatorial positions occupied by three N atoms from the tridentate ligand (average Cu—N = 2.004 Å and one O atom from a bidentate sulfate anion [Cu—O = 1.963 (2 Å]. The axial positions are occupied by one O atom from a coordinating water molecule [Cu—O = 2.230 (3 Å] and one weakly bonded O atom [Cu—O = 2.750 (2 Å] from the bidentate sulfate ion. The complex molecules are connected through O—H...O hydrogen bonds between the coordinating water molecules and sulfate ions from neighboring complexes, forming a double chain parallel to the c axis. The chains are stabilized through additional hydrogen bonds by one of the non-coordinating water molecules bridging between neighboring strands of the double chains. The remaining three water molecules fill the interstitial space between the double chains and are involved in an intricate hydrogen-bonding network that consolidates the structure.

[Zn(phen)(O,N,O)(H2O)] and [Zn(phen)(O,N)(H2O)] with O,N,O is 2,6-dipicolinate and N,O is L-threoninate: synthesis, characterization, and biomedical properties.

Science.gov (United States)

Chin, Lee-Fang; Kong, Siew-Ming; Seng, Hoi-Ling; Tiong, Yee-Lian; Neo, Kian-Eang; Maah, Mohd Jamil; Khoo, Alan Soo-Beng; Ahmad, Munirah; Hor, Tzi-Sum Andy; Lee, Hong-Boon; San, Swee-Lan; Chye, Soi-Moi; Ng, Chew-Hee

2012-10-01

Two ternary Zn(II) complexes, with 1,10-phenanthroline (phen) as the main ligand and a carboxylate-containing ligand [dipicolinate (dipico) or L-threoninate (L-Thr)] as the subsidiary ligand, were prepared and characterized by elemental analysis, Fourier transform IR, UV, and fluorescence spectroscopy, X-ray diffraction, molar conductivity, and electrospray ionization mass spectrometry. X-ray structure analysis shows that both [Zn(phen)(dipico)(H(2)O)]·H(2)O (1) and [Zn(phen)(L-Thr)(H(2)O)Cl]·2H(2)O (2) have octahedral geometry about the Zn(II) atom. Both complexes can inhibit topoisomerase I, and have better anticancer activity than cisplatin against nasopharyngeal cancer cell lines, HK1 and HONE-1, with concentrations causing 50 % inhibition of cell proliferation (IC(50)) in the low micromolar range. Complex 2 has the highest therapeutic index for HK1. Both Zn(II) complexes can induce cell death by apoptosis. Changing the subsidiary ligand in the Zn(II) complexes affects the UV-fluorescence spectral properties of the coordinated phen ligand, the binding affinity for some DNA sequences, nucleobase sequence-selective binding, the phase at which cell cycle progression was arrested for treated cancer cells, and their therapeutic index.

Solution synthesis, structure, and CO{sub 2} reduction reactivity of a Scandium(II) complex, {Sc[N(SiMe_3)_2]_3}{sup -}

Energy Technology Data Exchange (ETDEWEB)

Woen, David H.; Chen, Guo P.; Ziller, Joseph W.; Furche, Filipp; Evans, William J. [Department of Chemistry, University of California, Irvine, CA (United States); Boyle, Timothy J. [Sandia National Laboratories, Advanced Materials Laboratory, Albuquerque, NM (United States)

2017-02-13

The first crystallographically characterizable complex of Sc{sup 2+}, [Sc(NR{sub 2}){sub 3}]{sup -} (R=SiMe{sub 3}), has been obtained by LnA{sub 3}/M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR{sub 2}){sub 3} with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)]{sup +}, [K(18-c-6)]{sup +}, and [Cs(crypt)]{sup +} salts of the [Sc(NR{sub 2}){sub 3}]{sup -} anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 {sup 45}Sc nucleus. The Sc(NR{sub 2}){sub 3} reduction differs from Ln(NR{sub 2}){sub 3} reactions (Ln=Y and lanthanides) in that it occurs under N{sub 2} without formation of isolable reduced dinitrogen species. [K(18-c-6)][Sc(NR{sub 2}){sub 3}] reacts with CO{sub 2} to produce an oxalate complex, {K_2(18-c-6)_3}{[(R_2N)_3Sc]_2(μ-C_2O_4-κ"1O:κ"1O'')}, and a CO{sub 2}{sup -} radical anion complex, [(R{sub 2}N){sub 3}Sc(μ-OCO-κ{sup 1}O:κ{sup 1}O')K(18-c-6)]{sub n}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

(Dimethylformamide-κO(2-hydroxybenzoato-κ2O1,O1′[tris(1-methyl-1H-benzimidazol-2-ylmethyl-κN3amine-κN]manganese(II perchlorate dimethylformamide monosolvate

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Baoliang Qi

2010-10-01

Full Text Available In the title complex, [Mn(C7H5O3(C27H27N7(C3H7NO]ClO4·C3H7NO, the MnII ion is coordinated in a slightly distorted monocapped trigonal-prismatic geometry. The tris(1-methyl-1H-benzimidazol-2-ylmethylamine (Mentb ligand coordinates in a tetradentate mode and the coordination is completed by a bis-chelating salicylate ligand and a dimethylformamide ligand. The hydroxy group and the ortho H atoms of the salicylate ligand were refined as disordered over two sites with occupancies of 0.581 (8 and 0.419 (8. Both disorder components of the hydroxy group form intramolecular O—H...O hydrogen bonds.

One-Step Synthesis of Cu–ZnO@C from a 1D Complex [Cu0.02Zn0.98(C8H3NO6(C12H8N2]n for Catalytic Hydroxylation of Benzene to Phenol

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Guanghui Wang

2018-05-01

Full Text Available A novel one-dimensional bimetallic complex [Cu0.02Zn0.98(C8H3NO6(C12H8N2]n (“Complex” has been synthesized by a hydrothermal method. A Cu–ZnO@C composite was obtained by a one-step pyrolysis of Complex. Correlated with the characterization results, it is confirmed that both metallic Cu0 and ZnO nanoparticles were highly dispersed on/in the carbon substrate. This simple one-step pyrolysis method avoids the high-temperature pretreatment under H2 commonly required for preparation of such Cu–ZnO catalysts. The Cu–ZnO@C composite was tested with respect to its catalytic activities for the hydroxylation of benzene to phenol with H2O2. The results indicate that the benzene conversion, phenol yield, and phenol selectivity reached the maximum values (55.7%, 32%, and 57.5%, respectively at Complex carbonized at 600 °C, and were higher than those of the commercial mixed sample. Compared with the other candidate catalysts, the turnover frequency (TOF of our Cu–ZnO@C catalyst (117.9 mmol mol−1 s−1 can be ranked at the top. The higher catalytic activities should be due to the highly dispersed metallic Cu0 and ZnO particles as well as their synergistic interaction.

The interaction of NO2 with BaO: from cooperative adsorption to Ba(NO3)2 formation

International Nuclear Information System (INIS)

Yi, Cheol-Woo W.; Kwak, Ja Hun H.; Szanyi, Janos

2007-01-01

The effect of water on the morphology of BaO/Al2O3-based NOx storage materials was investigated using Fourier transform infrared spectroscopy, temperature programmed desorption, and time-resolved synchrotron X-ray diffraction techniques. The results of this multi-spectroscopy study reveal that, in the presence of water, surface Ba-nitrates convert to bulk nitrates, and water facilitates the formation of large Ba(NO3)2 particles. The conversion of surface to bulk Ba-nitrates is completely reversible, i.e. after the removal of water from the storage material a significant fraction of the bulk nitrates re-convert to surface nitrates. NO2 exposure of a H2O-containing (wet) BaO/Al2O3 sample results in the formation of nitrites and bulk nitrates exclusively, i.e. no surface nitrates form. After further exposure to NO2, the nitrites completely convert to bulk nitrates. The amount of NOx taken up by the storage material is, however, essentially unaffected by the presence of water, regardless of whether the water was dosed prior to or after NO2 exposure. Based on the results of this study we are now able to explain most of the observations reported in the literature on the effect of water on NOx uptake on similar storage materials

Synthesis and study of ruthenium (3) complexes with N-2-aminoethylimino-N,N-diacetic acid

International Nuclear Information System (INIS)

Ezerskaya, N.A.; Solovykh, T.P.; Egorushkina, N.A.; Shubochkin, L.K.

1981-01-01

Ru 3+ complexes with AEIDA are synthesized: Ru(AEIDA)Cl(H 2 O) (1), KRu(AEIDA)Cl 2 xH 2 O (2), KRu(HAEIDA)Clx1.5H 2 O (3), K 2 Ru(HAEIDA)xCl 4 xH 2 O (4), and KRu(H 2 AEIDA)Cl 4 (5), these complexes being geometric isomers of Ru 3+ complexes with ethylenediaminediacetate (EDDA). Tetradentant character of AEIDA coordination in 1 and 2, tridentant in 3 and bidental in 4 and 5 is established. Infrared spectra and electron spectra of complexes with AEIDA and EDDA are very much the same. Difference in complexone structure is the cause of observed difference of chlorine ions stability in Ru 3+ complexes with AEIDA and EDDA [ru

Effect of CO on NO and N2O conversions in nonthermal argon plasma

International Nuclear Information System (INIS)

Zhao Guibing; Argyle, Morris D.; Radosz, Maciej

2006-01-01

200-600 ppm of CO inhibit NO conversion in nonthermal Ar plasma, but do not produce N 2 O. However, 1.01% of CO has no effect on NO conversion, but produces N 2 O. In general, N 2 O conversion in Ar plasma decreases with increasing CO concentration. These experimental results cannot be explained by charge transfer reactions of Ar + . Selectivity analysis of all excited states of Ar possibly contributing to NO x conversion without and with CO suggests that only Ar( 3 P 2 ) contributes to NO x conversion and CO dissociation. A kinetic model of 43 reactions is required to model NO conversion or N 2 O conversion in Ar without CO, whereas 81 reactions are required to model NO conversion and N 2 O conversion in Ar with CO. At constant gas pressure, a single set of model parameters can predict NO conversion or N 2 O conversion without and with CO. All experimental results can be explained using a reaction mechanism in which excited neutral states of Ar are the only active species, which supports the conclusion that cations have a negligible impact on these nonthermal plasma reactions

Aluminum (III) and gallium (III) complexes with methyliminodiacetic acid: Crystal structures of Cat[M(Mida)2] (Cat+=Na, K, NH4; M3+=Al, Ga) and Me4N[Ga(Mida)2]·H2O

International Nuclear Information System (INIS)

Ilyukhin, A.B.; Petrosyants, S.P.; Milovanov, S.V.; Malyarik, M.A.

1997-01-01

The bis chelate complexes Cat[M(Mida) 2 ] and Me 4 N[Ga(Mida) 2 ]·H 2 O are synthesized from aqueous solutions M(NO 3 ) 3 -2H 2 Mida-CatOH (M 3+ =Al, Ga; Cat + =Na, K, NH 4 ) and Ga(OH) 3 -2H 2 Mida-Me 4 NOH. The crystal structures of the isostructural compounds Cat[M(Mida) 2 ] (Cat=Na, M=Al; Cat=K, M=Al; Cat=Na, M=Ga) and Me 4 N[Ga(Mida) 2 ]·H 2 O are determined by X-ray structure analysis. According to the X-ray powder diffraction analysis, all the six compounds Cat[M(Mida) 2 ] (Cat=Na, K, NH 4 ; M=Al, Ga) are isostructural. The octahedral anion in Cat[M(Mida) 2 ] and Me 4 N[Ga(Mida) 2 ]·H 2 O exhibits a trans(N)- fac configuration

Nqrs Data for C3H2Cl10N2PSb[C3HCl4N2P·Cl6HSb](Subst. No. 0601)

Science.gov (United States)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C3H2Cl10N2PSb [C3HCl4N2P·Cl6HSb] (Subst. No. 0601)

YCu(TeO32(NO3(H2O3: a novel layered tellurite

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Stuart J. Mills

2016-08-01

Full Text Available A new hydrated yttrium copper tellurite nitrate, yttrium(III copper(II bis[trioxidotellurate(IV] nitrate trihydrate, has been synthesized hydrothermally in a Teflon-lined autoclave and structurally determined using synchrotron radiation. The new phase is the first example containing yttrium, copper and tellurium in one structure. Its crystal structure is unique, with relatively strongly bound layers extending parallel to (020, defined by YO8, CuO4 and TeO3 polyhedra, while the NO3− anions and one third of the water molecules lie between those layers. The structural unit consists of [Cu2(TeO34]4− loop-branched chains of {Cu...Te...Cu...Te} squares running parallel to [001], which are linked further into layers only through Y(O,H2O8 polyhedra. Weak `secondary' Te bonds and O—H...O hydrogen-bonding interactions, involving water molecules and layer O atoms, link the layers and interlayer species. IR spectroscopic data are also presented.

Bis(2,2′-bipyridine-κ2N,N′(3-methylbenzoato-κ2O,O′zinc 3-methylbenzoate–3-methylbenzoic acid–water (1/1/2

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Qiu-qi Ye

2012-09-01

Full Text Available The title compound, [Zn(C8H7O2(C10H8N22](C8H7O2·C8H8O2·2H2O, is comprised of a Zn2+ cation, two 2,2′-bipydine (bipy ligands and one 3-methylbenzoate anion (L− together with one uncoordinating L− anion, one uncoordinating HL molecule and two lattice water molecules. The ZnII atom is coordinated by four N atoms of two bipy ligands and two O atoms from one L− ligand in a distorted octahedral geometry. Pairs of centrosymmetrically related complex molecules form dimers via slipped π-stacking interactions between bipy ligands with an interplanar distance of 3.470 (4 Å. The dimers are linked into supramolecular chains along [111], via C—H...O hydrogen bonds. The uncoordinated L− anions, HL molecules and water molecules are connected with each other via O—H...O hydrogen bonds, forming chains between the metal complex chains and binding them together via C—H...O contacts. The resulting layers parallel to (010 are further assembled into a three-dimensional supramolecular architecture through additional C—H...O interactions.

Physicochemical study of properties of complex oxides of the system Li2O-MoO3-SnO2

International Nuclear Information System (INIS)

Safonov, V.V.; Chaban, N.G.; Kuz'mina, N.P.; Vashman, A.A.; Petrov, K.I.

1990-01-01

By the method of differential thermal analysis using X-ray phase analysis in the Li 2 O-MoO 3 -SnO 2 system (Li 2 Sn(MoO 4 ) 3 -Sn(MoO 4 ) 2 cross section) formation of a new complex of the composition Li 2 Sn 3 (MoO 4 ) 7 incongruently melting at 480 deg C is ascertained. IR, Raman and NMR spectra of Li 4 SnMo 2 O 10 , Li 2 Sn(MoO 4 ) 3 and Li 2 Sn 3 (MoO 4 ) 7 complex oxides are presented. According to 7 Li NMR spectra of Li 4 SnMo 2 O 10 , Li 2 Sn(MoO 4 ) 3 and Li 2 Sn 3 (MoO 4 ) 7 complex are presented. According to 7 Li NMR spectra the value of the lithium diffusion increases in the series Li 4 SnMo 2 O 10 →Li 2 Sn(MoO 4 ) 3 →Li 2 Sn 3 (MoO 4 ) 7

Cd3(MoO4)(TeO3)2: A Polar 3D Compound Containing d10-d0 SCALP-Effect Cations.

Science.gov (United States)

Feng, Yuquan; Fan, Huitao; Zhong, Zhiguo; Wang, Hongwei; Qiu, Dongfang

2016-11-21

The new polar 3D cadmium molybdotellurite Cd 3 (MoO 4 )(TeO 3 ) 2 was obtained by means of a high-temperature solid-state method. Cd 3 (MoO 4 )(TeO 3 ) 2 is a monoclinic crystal system, and it exhibits the polar space group P2 1 (No. 4). The structure of Cd 3 (MoO 4 )(TeO 3 ) 2 can be viewed as a complicated 3D architecture that is composed of distorted CdO n (n = 6, 7) polyhedra, TeO 3 trigonal pyramids, and MoO 4 polyhedra. The compound features the first 3D NCS cadmium molybdotellurite with 1D 4- and 6-MR channels and a polar structure originating from the TeO 3 groups, MoO 4 groups, and displacements of d 10 Cd 2+ cations. The results were further confirmed by calculations of the net polarization. The UV-vis spectrum and thermal properties indicate that Cd 3 (MoO 4 )(TeO 3 ) 2 exhibits a broad transparent region and excellent thermal stability. SHG tests of Cd 3 (MoO 4 )(TeO 3 ) 2 revealed that its response is approximately the same as that of KH 2 PO 4 at the same grain size between 105 and 150 μm and that it is phase-matchable.

Ab initio studies of O2-(H2O)n and O3-(H2O)n anionic molecular clusters, n≤12

DEFF Research Database (Denmark)

Bork, Nicolai Christian; Kurtén, T.; Enghoff, Martin Andreas Bødker

2011-01-01

that anionic O2−(H2O)n and O3−(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding. Although...... clustering up to 12 H2O, we find that the O2 and O3 anions retain at least ca. 80 % of the charge and are located at the surface of the cluster. The O2− and O3− speicies are thus accessible for further reactions. Finally, the thermodynamics of a few relevant cluster reactions are considered....

On the ability of chemical transport models to simulate the vertical structure of the N2O, NO2 and HNO3 species in the mid-latitude stratosphere

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G. Berthet

2006-01-01

Full Text Available In this paper we study the impact of the modelling of N2O on the simulation of NO2 and HNO3 by comparing in situ vertical profiles measured at mid-latitudes with the results of the Reprobus 3-D CTM (Three-dimensional Chemical Transport Model computed with the kinetic parameters from the JPL recommendation in 2002. The analysis of the measured in situ profile of N2O shows particular features indicating different air mass origins. The measured N2O, NO2 and HNO3 profiles are not satisfyingly reproduced by the CTM when computed using the current 6-hourly ECMWF operational analysis. Improving the simulation of N2O transport allows us to calculate quantities of NO2 and HNO3 in reasonable agreement with observations. This is achieved using 3-hourly winds obtained from ECMWF forecasts. The best agreement is obtained by constraining a one-dimensional version of the model with the observed N2O. This study shows that the modelling of the NOy partitioning with better accuracy relies at least on a correct simulation of N2O and thus of total NOy.

Mass spectrometric determination of partial electron impact ionization cross sections of No, No2, and N2O from threshold up to 180 eV

International Nuclear Information System (INIS)

Kim, Y. B.

1982-01-01

Electron impact ionization of nitric oxide (NO), nitrogen dioxide (NO 2 ) and nitrous oxide (N 2 O) has been studied as a function of electron energy up to 180 eV with a double focussing mass spectrometer Varian MAT CH5 and an improved Nier type electron impact ion source. Relative partial ionization cross sections were measured for the processes NO + + 2e, NO ++ + 3e, and NO 2 + e -> NO + 2 + 2e, NO ++ + 3e and N 2 O + e -> N 2 O + + 2e. An accurate measurement of the cross section ratios q(NO 2+ /NO)/q(NO + /NO) and q(NO 2 2 /NO 2 )/q(NO + 2 /NO 2 ) has been made. Relative cross section functions were calibrated absolutely with two different normalization methods. Moreover, both metastable and collision induced dissociations of N 2 O + were studied quantitatively using the technique of decoupling the acceleration and deflection electric fields. Using the n- th root extrapolation the following ionization potentials have been derived from the cross section functions near threshold: NO + (X 1 Σ + ); NO ++ ; NO + 2 ; NO 2 ++ ; N 2 O + (X 2 π). These results are compared with previous measurements and theoretical calculations, where available. Part of the results presented have been already published in seven papers by the author. (Author)

Photocatalytic decomposition of N2O over TiO2/g-C3N4 photocatalysts heterojunction

Science.gov (United States)

Kočí, K.; Reli, M.; Troppová, I.; Šihor, M.; Kupková, J.; Kustrowski, P.; Praus, P.

2017-02-01

TiO2/g-C3N4 photocatalysts with the various TiO2/g-C3N4 weight ratios from 1:2 to 1:6 were fabricated by mechanical mixing in water suspension followed by calcination. Pure TiO2 was prepared by thermal hydrolysis and pure g-C3N4 was prepared from commercial melamine by thermal annealing at 620 °C. All the nanocomposites were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, photoelectrochemical measurements and nitrogen physisorption. The prepared mixtures along with pure TiO2 and g-C3N4 were tested for the photocatalytic decomposition of nitrous oxide under UVC (λ = 254 nm), UVA (λ = 365 nm) and Vis (λ > 400 nm) irradiation. The TiO2/g-C3N4 nanocomposites showed moderate improvement compared to pure g-C3N4 but pure TiO2 proved to be a better photocatalyst under UVC irradiation. However, under UVA irradiation conditions, the photocatalytic activity of TiO2/g-C3N4 (1:2) nanocomposite exhibited an increase compared to pure TiO2. Nevertheless, further increase of g-C3N4 amount leads/led to a decrease in reactivity. These results are suggesting the nanocomposite with the optimal weight ratio of TiO2 and g-C3N4 have shifted absorption edge energy towards longer wavelengths and decreased the recombination rate of charge carriers compared to pure g-C3N4. This is probably due to the generation of heterojunction on the TiO2/g-C3N4 interface.

Diaquabis[2-(2-hydroxyethylpyridine-κ2N,O]cobalt(II dichloride

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Hocine Merazig

2013-08-01

Full Text Available In the title salt, [Co(C7H9NO2(H2O2]Cl2, the CoII cation, located on an inversion center, is N,O-chelated by two hydroxyethylpyridine ligands and coordinated by two water molecules in a distorted O4N2 octahedral geometry. In the crystal, the Cl− anions link with the complex cations via O—H...Cl hydrogen bonds, forming a three-dimensional supramolecular architecture. π–π stacking is observed between the pyridine rings of adjacent molecules [centroid–centroid distance = 3.5810 (11 Å].

Study of GaN nanorods converted from β-Ga2O3

Science.gov (United States)

Li, Yuewen; Xiong, Zening; Zhang, Dongdong; Xiu, Xiangqian; Liu, Duo; Wang, Shuang; Hua, Xuemei; Xie, Zili; Tao, Tao; Liu, Bin; Chen, Peng; Zhang, Rong; Zheng, Youdou

2018-05-01

We report here high-quality β-Ga2O3 nanorods (NRs) grown on sapphire substrates by hydrothermal method. Ammoniating the β-Ga2O3 NRs results in strain-free wurtzite gallium nitride (GaN) NRs. It was shown by XRD and Raman spectroscopy that β-Ga2O3 was partially converted to GaN/β-Ga2O3 at 1000 °C and then completely converted to GaN NRs at 1050 °C, as confirmed by high-resolution transmission electron microscopy (HRTEM). There is no band-edge emission of β-Ga2O3 in the cathodoluminescence spectrum, and only a deep-level broad emission observed at 3.68-3.73 eV. The band edge emission (3.39 eV) of GaN NRs converted from β-Ga2O3 can also be observed.

Organodioxygen complexes of some heavy metal ions and their oxygen transfer reactions

International Nuclear Information System (INIS)

Tarafder, M.T.H.; Mei Ling; Gino Mariotto

2003-09-01

Several novel organodioxygen complexes of lanthanide ions, viz., lanthanum(m) and cerium(IV) have been synthesized containing a number of organic co- ligands. The complexes characterized were, [La(0 2 )(det)(N0 3 ) 2 ] (1), [La(O 2 )(tet)(NO 3 ) 2 ] (2), [La(O 2 )(C 5 H 5 N)2NO 3 ] (3), [La(O 2 )(C 6 H 18 N 3 PO) 2 (NO 3 ) 2 ] (4), [La(0 2 )(OPPh 3 ) 2 (N0 3 ) 2 ] (5), [La(O 2 ) 2 (NH 2 CH 2 CH 2 NH 2 ) 2 NO 3 ] (6), [La(O 2 )(PPh 3 ) 2 (NO 3 ) 2 ] (7) and [Ce(O 2 )(C 6 H 18 N 3 PO) 2 (NO 3 ) 3 ] (8). IR and Raman spectra revealed that (3) was a peroxo complex while the others were, in particular, superoxo type. The IR spectrum of (3) gives V 1 (O-O) at 851 cm -1 while the Raman spectra of (4), (5), (7) and (8) give V 1 (O 2 ) bands at 1046 cm -1 , 1032 cm 1 , 1100 cm -1 and 1046 cm -1 , respectively. The oxygen transfer reactions of two selected complexes were carried out under stoichiometric conditions. The complex containing a bidentate ligand, (6), was found to oxidize triphenylphosphine and trans-stilbene to their oxides while the complex containing tridentate ligand (1) was stable and inert towards oxidation. (author)

Investigation of N2O Production from 266 and 532 nm Laser Flash Photolysis of O3/N2/O2 Mixtures

Science.gov (United States)

Estupinan, E. G.; Nicovich, J. M.; Li, J.; Cunnold, D. M.; Wine, P. H.

2002-01-01

Tunable diode laser absorption spectroscopy has been employed to measure the amount of N2O produced from laser flash photolysis of O3/N2/O2 mixtures at 266 and 532 nm. In the 532 nm photolysis experiments very little N2O is observed, thus allowing an upper limit yield of 7 x 10(exp -8) to be established for the process O3 + N2 yield N2O + O2, where O3 is nascent O3 that is newly formed via O(3P(sub J)) + O2 recombination (with vibrational excitation near the dissociation energy of O3). The measured upper limit yield is a factor of approx. 600 smaller than a previous literature value and is approximately a factor of 10 below the threshold for atmospheric importance. In the 266 nm photolysis experiments, significant N2O production is observed and the N2O quantum yield is found to increase linearly with pressure over the range 100 - 900 Torr in air bath gas. The source of N2O in the 266 nm photolysis experiments is believed to be the addition reaction O(1D(sub 2)) + N2 + M yields (k(sub sigma)) N2O + M, although reaction of (very short-lived) electronically excited O3 with N2 cannot be ruled out by the available data. Assuming that all observed N2O comes from the O(1D(sub 2)) + N2 + M reaction, the following expression describes the temperature dependence of k(sub sigma) (in its third-order low-pressure limit) that is consistent with the N2O yield data: k(sub sigma) = (2.8 +/- 0.1) x 10(exp -36)(T/300)(sup -(0-88+0.36)) cm(sup 6) molecule(sup -2)/s, where the uncertainties are 2(sigma) and represent precision only. The accuracy of the reported rate coefficients at the 95% confidence level is estimated to be 30 - 40% depending on the temperature. Model calculations suggest that gas phase processes initiated by ozone absorption of a UV photon represent about 1.4% of the currently estimated global source strength of atmospheric N2O. However, these processes could account for a significant fraction of the oxygen mass-independent enrichment observed in atmospheric N2O, and

Synthesis and Structures of Two Lanthanide Complexes Containing a Mixed Ligand System: [Ln(Phen)2(L)3(HL)]·H2O [Ln = La, Ce; Phen = Phenanthroline; HL = Salicylic Acid

International Nuclear Information System (INIS)

Iravani, Effat; Nami, Navabeh; Nabizadeh, Fatemeh; Bayani, Elham; Neumueller, Bernhard

2013-01-01

The reaction of LnCl 3 ·7H 2 O [Ln = La (1), Ce (2)] with salicylic acid (HL) and 1,10-phenanthroline (Phen) at 20 .deg. C in H 2 O/ethanol gave after work-up and recrystallization two novel lanthanide complexes with general formula [Ln(Phen) 2 (L) 3 (HL)]·H 2 O. Compounds 1 and 2 were characterized by IR and UV-Vis spectroscopy, TGA, CHN as well as by X-ray analysis. According to these results, compounds 1 and 2 are isostructural and contain Ln 3+ ions with coordination number nine. Complexes 1 and 2 consist of two Phen, one neutral HL and three L anions (two L anions act as monodentate ligands and the third one is chelating to Ln 3+ ). Thermal decomposition led to primary loss of the Phen molecules. Then HL molecules and finally L moieties left the material to give Ln 2 O 3

{2-[(2-Acetylhydrazin-1-ylidenemethyl-κ2N1,O]-6-methoxyphenolato-κO1}(nitrato-κOcopper(II monohydrate

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Ibrahima Elhadj Thiam

2010-02-01

Full Text Available In the title complex, [Cu(C10H11N2O3(NO3]·H2O, prepared from the Schiff base N′-(3-methoxy-2-oxidobenzylideneacetohydrazide, the CuII atom is coordinated by two O atoms and one N atom from the ligand and one O atom from a nitrate group in a distorted square-planar geometry. The CuII atom has a weak interaction with another O atom of the nitrate group. The two O atoms of the tridentate Schiff base ligand are in a trans arrangement. O—H...O and N—H...O hydrogen bonds involving the uncoordinated water molecule are observed.

The synthesis and structural characterization of the technetium nitrosyl complexes [TcCl(NO)(SC5H4N)(PPh3)2] and [Tc(NO)(SC5H4N)2(PPh3)

Science.gov (United States)

Nicholson, Terrence L.; Mahmood, Ashfaq; Muller, Peter; Davison, Alan; Storm-Blanchard, Shannon; Jones, Alun G.

2011-01-01

The reaction of the Tc(I) complex [Tc(NO)Cl2(HOMe)(PPh3)2] with stoichiometric amounts of 2-mercatopyridine and a proton scavenger yields [Tc(NO)Cl(Spy)(PPh3)2] or [Tc(NO)(Spy)2(PPh3)], depending upon quantities of ligands employed. These two complexes have been structurally characterized. The small bite angles of the bidentate mercaptopyridine ligands cause significant deviation from octahedral coordination geometry. PMID:23750048

Solid-state thermal decomposition of the [Co(NH3)5CO3]NO3·0.5H2O complex: A simple, rapid and low-temperature synthetic route to Co3O4 nanoparticles

International Nuclear Information System (INIS)

Farhadi, Saeid; Safabakhsh, Jalil

2012-01-01

Highlights: ► [Co(NH 3 ) 5 CO 3 ]NO 3 ·0.5H 2 O complex was used for preparing pure Co 3 O 4 nanoparticles. ► Co 3 O 4 nanoparticles were prepared at low temperature of 175 °C. ► Co 3 O 4 nanoparticles show a weak ferromagnetic behaviour at room temperature. ► The method is simple, low-cost and suitable for the production of Co 3 O 4 . - Abstract: Co 3 O 4 nanoparticles were easily prepared via the decomposition of the pentammine(carbonato)cobalt(III) nitrate precursor complex [Co(NH 3 ) 5 CO 3 ]NO 3 ·0.5H 2 O at low temperature (175 °C). The product was characterized by thermal analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV–visible spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Brunauer–Emmett–Teller (BET) specific surface area measurements and magnetic measurements. The FT-IR, XRD, Raman and EDX results indicated that the synthesized Co 3 O 4 nanoparticles are highly pure and have a single phase. The TEM analysis revealed nearly uniform and quasi-spherical Co 3 O 4 nanoparticles with an average particle size of approximately 10 nm. The optical absorption spectrum of the Co 3 O 4 nanoparticles showed two direct band gaps of 2.18 and 3.52 eV with a red shift in comparison with previous reported values. The prepared Co 3 O 4 nanoparticles showed a weak ferromagnetic behaviour that could be attributed to uncompensated surface spins and/or finite-size effects. Using the present method, Co 3 O 4 nanoparticles can be produced without expensive organic solvents and complicated equipment. This simple, rapid, safe and low-cost synthetic route can be extended to the synthesis of other transition-metal oxides.

Bis{2-[(pyridin-2-ylmethylideneamino]benzoato-κ3N,N′,O}chromium(III nitrate monohydrate

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Elena A. Buvaylo

2014-04-01

Full Text Available The title complex salt hydrate, [Cr(C13H9N2O22]NO3·H2O, comprises discrete cations, nitrate anions and solvent water molecules. The CrIII atom is octahedrally coordinated by two anionic Schiff base ligands with the O atoms being cis. The two ligands differ significantly with dihedral angles between the pyridine and benzene rings of 4.8 (2 and 24.9 (2°. The nitrate anion and solvent water molecule were modelled as being disordered, with the major components having site-occupancy values of 0.856 (14 and 0.727 (16, respectively. The crystal is built of alternating layers of cations and of anions plus water molecules, stacked along the c axis.

Synthesis and crystal structures of new complexes of Np(V) glycolate with 2,2'-bipyridine, [NpO2(C10H8N2)(OOC2H2OH)].1.5H2O and [NpO2(C10H8N2)(OOC2H2OH)].2.5H2O

International Nuclear Information System (INIS)

Charushnikova, I.A.; Krot, N.N.; Starikova, Z.A.

2009-01-01

Single crystals were prepared, and the structures of two complexes of Np(V) glycolate with 2,2'-bipyridine of the compositions [NpO 2 (C 10 H 8 N 2 )(OOC 2 H 2 OH)].1.5H 2 O (I) and [NpO 2 (C 10 H 8 N 2 )(OOC 2 H 2 OH)]2.5H 2 O (II) were studied. The structures of the compounds are based on neptunyl-glycolate chains in which the glycolate anion manifests its complexation ability in different manner. In structure I, the bidentate-bridging anion links the adjacent NpO 2 - cations through the oxygen atoms of the carboxylate group. The neptunyl-glycolate chains of I exhibits the mutual coordination of the NpO 2 - cations acting toward each other simultaneously as ligands and coordinating centers. In compound II, the glycolate anion is bidentately coordinated to one neptunium atom to form a planar five-membered metallocycle [NpOCCO]. The O atom external with respect to the metallocycle is in the coordination environment of the adjacent neptunyl. The nitrogen-containing molecular ligand Bipy is included into the coordination environment of Np. The coordination polyhedron of the Np atoms in both structures is a pentagonal bipyramid in which the average Np-N bond length is 2.666 Aa (I) and 2.596 Aa (II). (orig.)

Synthesis, structure, and characterization of two new bismuth(III) selenite/tellurite nitrates: [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3})

Energy Technology Data Exchange (ETDEWEB)

Meng, Chang-Yu; Wei, Ming-Fang [Department of Chemistry and Materials, Yulin Normal University,Yulin, Guangxi 537000 (China); Geng, Lei, E-mail: lgeng.cn@gmail.com [Department of Materials Science and Engineering, Huaibei Normal University, Huaibei, Anhui 235000 (China); Hu, Pei-Qing; Yu, Meng-Xia [Department of Chemistry and Materials, Yulin Normal University,Yulin, Guangxi 537000 (China); Cheng, Wen-Dan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2016-07-15

Two new bismuth(III) selenite/tellurite nitrates, [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3}), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV–vis–NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P2{sub 1}/c with a=9.9403(4) Å, b=9.6857(4) Å, c=10.6864(5) Å, β=93.1150(10)° for [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and a=8.1489(3) Å, b=9.0663(4) Å, c=7.4729(3) Å, β=114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}] {sup 3}{sub ∞} with NO{sub 3}{sup −} anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO{sub 3})](NO{sub 3}) features 2D bismuth(III) tellurite [Bi(TeO{sub 3}){sub 2}]{sup 2}{sub ∞} layers separated by NO{sub 3}{sup −} anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors. - Graphical abstract: Two novel bismuth{sup III} selenite/tellurite nitrates [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) with 3D tunnel structure and [Bi(TeO{sub 3})](NO{sub 3}) with 2D layer structure have been firstly synthesized and characterized. Display Omitted - Highlights: • Two novel bismuth{sup III} nitrates [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3}) were firstly

Kinetics and branching ratios of the reactions NH2+NO2->N2O+H2O and NH2+NO2->H2NO+NO studied by pulse radiolysis combined with time-resolved infrared diode laser spectroscopy

DEFF Research Database (Denmark)

Meunier, H.; Pagsberg, Palle Bjørn; Sillesen, A.

1996-01-01

studied by monitoring the decay of NH2 and the simultaneous formation of N2O and NO by time-resolved infrared diode laser spectroscopy. The decay rate of NH2 was studied as a function of NO2 concentration to obtain an overall rate constant k(NH2 + NO2) = (1.35 +/- 0.15) X 10(-11) molecule(-1) cm(3) s(-1...

Aquachlorido{6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilodimethylidyne]diphenolato-κ2O1,N,N′,O1′}cobalt(III monohydrate

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Jianxin Xing

2009-04-01

Full Text Available The title compound, [Co(C18H18N2O4Cl(H2O]·H2O, contains a distorted octahedral cobalt(III complex with a 6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilodimethylidyne]diphenolate ligand, a chloride and an aqua ligand, and also a disordered water solvent molecule (half-occupancy. The CoIII ion is coordinated in an N2O3Cl manner. Weak O—H...O hydrogen bonds may help to stabilize the crystal packing.

[Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

Science.gov (United States)

Cao, Na; Wang, Rui; Liao, Ting-ting; Chen, Nuo; Zheng, Xun-hua; Yao, Zhi-sheng; Zhang, Hai; Butterbach-Bahl, Klaus

2015-09-01

Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields. The initial concentrations of soil nitrate and dissolved organic carbon (DOC) were set at approximately 50 mg.kg-1 and mg.kg-1, respectively, by adding a mixture solution of KNO3 and glucose. The emissions of N2, N2O NO, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each soil sample were measured simultaneously, using a gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that the accumulative emissions of N2, N2O and NO of the two soil samples for the entire incubation period were 6 - 8, 20, and 15 - 18 mg.kg-1, respectively. By measuring the cumulative emissions of denitrification gases (N, = N2 + N2O + NO) we were able to explain 95% to 98% of observed changes in s1ifr nilrate concentrations. The mass fractions of N2, N2O and NO emissions to Nt were approximately 15% -19%, 47% -49%, and 34% -36%, respectively. Thus, in our experiments N2O and NO were the main products of denitrification for the entire incubation period. However, as the temporal courses of hourly or daily production of the denitrification gases showed, NO production dominated and peaked firstly, and then N2O, before finally N2 became the dominant product. Our results show the high temporal dynamic of

Bis(μ-pyridazine-3-carboxylato-κ2O:O′bis[aquadioxido(pyridazine-3-carboxylato-κ2N2,Ouranium(VI] dihydrate

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Janusz Leciejewicz

2009-01-01

Full Text Available The structure of the binuclear title complex, [U2(C5H3N2O24O4(H2O2]·2H2O, is composed of centrosymmetric dimers in which each UO22+ ion is coordinated by two ligand molecules. One donates its N,O-bonding group and the other donates both carboxylate O atoms. Each of the latter bridges adjacent uranyl ions. The coordination environment of the metal center is a distorted pentagonal bipyramid. The dimers are interconnected by O—H...O hydrogen bonds between coordinated and uncoordinated water molecules and carboxylate O atoms. An intramolecular O—H...N interaction is also present.

Laser flash-photolysis and gas discharge in N2O-containing mixture: kinetic mechanism

Science.gov (United States)

Kosarev, Ilya; Popov, Nikolay; Starikovskaia, Svetlana; Starikovskiy, Andrey; mipt Team

2011-10-01

The paper is devoted to further experimental and theoretical analysis of ignition by ArF laser flash-photolysis and nanosecond discharge in N2O-containing mixture has been done. Additional experiments have been made to assure that laser emission is distributed uniformly throughout the cross-section. The series of experiments was proposed and carried out to check validity of O(1D) determination in experiments on plasma assisted ignition initiated by flash-photolysis. In these experiments, ozone density in the given mixture (mixture composition and kinetics has been preliminary analyzed) was measured using UV light absorption in Hartley band. Good coincidence between experimental data and results of calculations have been obtained Temporal behavior of energy input, electric field and electric current has been measured and analyzed. These data are considered as initial conditions for numerical modeling of the discharge in O2:N2O:H2:Ar = 0.3:1:3:5 mixture. Ion-molecular reactions and reactions of active species production in Ar:H2:O2:N2O mixture were analyzed. The set of reactions to describe chemical transformation in the system due to the discharge action has been selected.

N2O isotopomers and N2:N2O ratio as indicators of denitrification in ecosystems

International Nuclear Information System (INIS)

Mander, Ülo; Zaman, Mohammad

2015-01-01

The world is experiencing climate change and variability due to increased greenhouse gas (GHG) emissions. The main GHG’s of concern are nitrous oxide (N 2 O), carbon dioxide (CO 2 ) and methane (CH 4 ). Agriculture contributes approximately 14% of the world’s GHG emissions. Nitrous oxide is one of the key GHG and ozone (O 3 ) depleting gas, constituting 7% of the anthropogenic greenhouse effect. On a molecular basis, N 2 O has a 310- and 16-fold greater global warming potential than each of CO 2 and CH 4 , respectively, over a 100-year period. Nitrous oxide can be produced through both chemical and biochemical pathways. They occur during denitrification (the stepwise conversion of nitrate (NO 3 - ) to nitrogen gas (N 2 ) and during nitrification by ammonia-oxidizing archea (bacteria) during the oxidation of hydroxylamine (NH 2 OH) to nitrite (NO 2 - ) which is then reduced to N 2 O and N 2 by nitrifier denitrification or heterotrophic denitrification

Kinetics of Heterogeneous NO and N2O Reduction at FBC Conditions

DEFF Research Database (Denmark)

Johnsson, Jan Erik; Jensen, Anker; Nielsen, Jannik Steen

1999-01-01

of the combustion chamber and adding secondary air in the top or in the cyclone. The change in reaction pathways for N2O and NO formation and reduction is very complex, and the catalytic activity of the solid material in the boiler may vary with the air staging. Samples of solids taken from large scale tests...

Bis[μ-2-(2,4-difluorophenyl-1,3-bis(1,2,4-triazol-1-ylpropan-2-olato-κ4N2,O:O,N2′]bis[(acetato-κ2O,O′nickel(II] methanol hemisolvate

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Feng Zhang

2010-01-01

Full Text Available In the title complex, [Ni2(C13H11F2N6O2(C2H3O22]·0.5CH3OH, there are two half-molecules in the asymmetric unit. The two centrosymmetrically related NiII atoms, each attached to an acetate ligand, are linked by two fluconazole ligands. Each NiII atom is six-coordinated in a distorted octahedral geometry by two N atoms of the triazole groups and two bridging O atoms from two different fluconazole ligands and two O atoms from a chelating acetate ligand. In the crystal structure, the half-occupied methanol solvent molecule is linked to a triazole group via an O—H...N hydrogen bond.

Estudo da viabilidade de obtenção de cerâmicas de SiC por infiltração espontânea de misturas eutéticas de Y2O3-AlN, Y2O3-Al2O3, R2O3-AlN Study of the viability to produce SiC ceramics by Y2O3-AlN, Y2O3-Al2O3, R2O3-AlN spontaneous infiltration