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Sample records for h2o molecule ii

  1. Near Infrared Spectroscopy of M Dwarfs. II. H2O Molecule as an Abundance Indicator of Oxygen

    CERN Document Server

    Tsuji, Takashi; Takeda, Yoichi

    2014-01-01

    Based on the near infrared spectra (R~20000) of M dwarfs, oxygen abundances are determined from the ro-vibrational lines of H2O. Although H2O lines in M dwarfs are badly blended each other and the continuum levels are depressed appreciably by the collective effect of numerous H2O lines themselves, quantitative analysis of H2O lines has been carried out by referring to the pseudo-continua both on the observed and theoretical spectra. For this purpose, the pseudo-continuum on the theoretical spectrum has been evaluated by the use of the recent high-precision H2O line-list. Then, we propose a simple and flexible method of analyzing equivalent widths (EWs) of blended features by the use of a mini curve-of-growth (CG), which is a small portion of the usual CG around the observed EW. The mini CG is generated by using the theoretical EWs evaluated from the synthetic spectrum by exactly the same way as the EWs are measured from the observed spectrum. The observed EW is converted to the abundance by the use of the min...

  2. Molecule survival in magnetized protostellar disk winds. II. Predicted H2O line profiles versus Herschel/HIFI observations

    CERN Document Server

    Yvart, W; Forets, G Pineau des; Ferreira, J

    2016-01-01

    We investigate whether the broad wings of H2O emission identified with Herschel towards low-mass Class 0 and Class 1 protostars may be consistent with an origin in a dusty MHD disk wind, and the constraints it would set on the underlying disk properties. We present synthetic H2O line profiles predictions for a typical MHD disk wind solution with various values of disk accretion rate, stellar mass, extension of the launching area, and view angle. We compare them in terms of line shapes and intensities with the HIFI profiles observed by the WISH Key Program. We find that a dusty MHD disk wind launched from 0.2--0.6 AU AU to 3--25 AU can reproduce to a remarkable degree the observed shapes and intensities of the broad H2O component, both in the fundamental 557 GHz line and in more excited lines. Such a model also readily reproduces the observed correlation of 557 GHz line luminosity with envelope density, if the infall rate at 1000 AU is 1--3 times the disk accretion rate in the wind ejection region. It is also ...

  3. Cross talk between H2O2 and interacting signal molecules under plant stress response

    Directory of Open Access Journals (Sweden)

    Ina eSaxena

    2016-04-01

    Full Text Available It is well established that oxidative stress is an important cause of cellular damage. During stress condition plants have evolved regulatory mechanism to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of ROS, which is subsequently converted to H2O2. H2O2 is continuously produced as the by-product of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 acts as a key regulator of many biological processes because H2O2 has been identified as an important second messenger in signal transduction networks. In this review we discuss potential roles of H2O2 and other signaling molecule during various stress responses.

  4. Hydrothermal Synthesis and Structure of a Copper(II) Complex, [Cu(4,4'-bpy)(H2O)3]SO4·2H2O

    Institute of Scientific and Technical Information of China (English)

    林碧洲; 刘培德

    2003-01-01

    The title complex [Cu(4,4'-bpy)(H2O)3]SO4@2H2O (Mr = 405.86) was synthesized under hydrothermal conditions and its crystal structure has been determined by X-ray diffraction. It crystallizes in the hexagonal system, space group P61 with a = 11.1870(4), c = 21.578(1)(A°), V = 2338.6(2)(A°)3, Dc = 1.729 g/cm3, Z = 6, ((MoKα) = 1.583 mm-1 and F(000) = 1254. The final R and wR are 0.0253 and 0.0416 for 1458 observed reflections with I≥2((I), respectively. It was revealed that the square pyramidal Cu(II) sites are linked through 4,4'-bipyridine groups, forming infinite one-dimensional chains, with the sulfate anions and lattice water molecules occupying the inter-chain positions. During the electrostatic interactions, there exist O...O hydrogen bonds and π-πstacking interactions between the parallel aromatic bipy rings in the structure.

  5. Two different zinc(II)-aqua complexes held up by a metal-oxide based support: Synthesis, crystal structure and catalytic activity of [HMTAH]2[{Zn(H2O)5}{Zn(H2O)4}{Mo7O24}].2H2O (HMTAH = protonated hexamethylenetetramine)

    Indian Academy of Sciences (India)

    T Arumuganathan; A Srinivasarao; T Vijay Kumar; Samar K Das

    2008-01-01

    An inorganic−organic hybrid material, [HMTAH]2[{Zn(H2O)5}{Zn(H2O)4}{Mo7O24}].2H2O (1) (where HMTAH = protonated hxamethylenetetramine) has been synthesized and structurally characterized. The compound 1 crystallizes in a monoclinic space group 2/. The crystal data of 1: = 43.12(3), = 12.399(10), = 16.285(13), = 111.131(11), = 8. Its crystal structure shows that two different Zn(II)-aqua complexes, [Zn(H2O)5]2+ and [Zn(H2O)4]2+ are covalently coordinated to a heptamolybdateanion [Mo7O24]6- resulting in an anionic species of polyoxometalate supported zinc-aqua complexes, [{Zn(H2O)}{Zn(H2O)4}{Mo7O24}]2-, that is stabilized with two protonated hexamethylenetetramine cations in the title compound 1. In the crystal structure, both lattice water molecules are found to interact with the heptamolybdate cluster anion and the protonated hexamethylenetetramine cation resulting in an intricate three-dimensional hydrogen bonding network. Interestingly, compound 1 exhibits catalytic activity towards oxidation of some primary alcohols.

  6. Molecules based on M(v) (M=Mo, W) and Ni(II) ions: a new class of trigonal bipyramidal cluster and confirmation of SMM behavior for the pentadecanuclear molecule {NiII[NiII(tmphen)(MeOH)]6[Ni(H2O)3]2[micro-CN]30[WV(CN)3]6}.

    Science.gov (United States)

    Hilfiger, Matthew G; Zhao, Hanhua; Prosvirin, Andrey; Wernsdorfer, Wolfgang; Dunbar, Kim R

    2009-07-14

    The preparation, single crystal X-ray crystallography, and magnetic properties are reported for four new clusters based on [M'V(CN)8]3- octacyanometallates (M'=Mo, W). Reactions of [M'V(CN)8]3- with mononuclear NiII ions in the presence of the tmphen blocking ligand (tmphen=3,4,7,8-tetramethyl-1,10-phenanthroline) in a 2:3:6 ratio, respectively, lead to the formation of the trigonal bipyramidal clusters [NiII(tmphen)2]3[M'V(CN)8]2. Analogous reactions with the same starting materials performed in a 2:3:2 ratio, respectively, produce pentadecanuclear clusters of the type {NiII[NiII(tmphen)(MeOH)]6[Ni(H2O)3]2[micro-CN]30[WV(CN)3]6}. The W2Ni3 (1) and Mo2Ni3(2) pentanuclear clusters and the W6Ni9 (3) and Mo6Ni9 (4) pentadecanuclear molecules are isostructural to each other and crystallize in the space groups P2(1)/c and R3 respectively. Magnetic measurements indicate that the ground states for the trigonal bipyamidal clusters are S=4 as a consequence of ferromagnetic coupling with JW-Ni=9.5 cm(-1), JMo-Ni=10 cm(-1). The pentadecanuclear clusters exhibit ferromagnetic coupling as well, which leads to S=12 ground states (JW-Ni=12 cm(-1), JMo-Ni=12.2 cm(-1)). Reduced magnetization studies on the W-Ni analogues support the conclusion that they exhibit a negative axial anisotropy term; the fits give D values of -0.24 cm(-1) for the W2Ni3 cluster and D=-0.04 cm(-1)for the W6Ni9 cluster. AC susceptibility measurements indicate the beginning of an out-of-phase signal for the W2Ni3 and the W6Ni9 compounds, but detailed low temperature studies on small crystals by the microSQUID technique indicate that only the pentadecanuclear cluster exhibits hysteresis in accord with SMM behavior. Neither Mo cluster reveals any evidence for slow paramagnetic relaxation at low temperatures.

  7. Type II skeletal myofibers possess unique properties that potentiate mitochondrial H(2)O(2) generation.

    Science.gov (United States)

    Anderson, Ethan J; Neufer, P Darrell

    2006-03-01

    Mitochondrial dysfunction is implicated in a number of skeletal muscle pathologies, most notably aging-induced atrophy and loss of type II myofibers. Although oxygen-derived free radicals are thought to be a primary cause of mitochondrial dysfunction, the underlying factors governing mitochondrial superoxide production in different skeletal myofiber types is unknown. Using a novel in situ approach to measure H(2)O(2) production (indicator of superoxide formation) in permeabilized rat skeletal muscle fiber bundles, we found that mitochondrial free radical leak (H(2)O(2) produced/O(2) consumed) is two- to threefold higher (P < 0.05) in white (WG, primarily type IIB fibers) than in red (RG, type IIA) gastrocnemius or soleus (type I) myofibers during basal respiration supported by complex I (pyruvate + malate) or complex II (succinate) substrates. In the presence of respiratory inhibitors, maximal rates of superoxide produced at both complex I and complex III are markedly higher in RG and WG than in soleus muscle despite approximately 50% less mitochondrial content in WG myofibers. Duplicate experiments conducted with +/-exogenous superoxide dismutase revealed striking differences in the topology and/or dismutation of superoxide in WG vs. soleus and RG muscle. When normalized for mitochondrial content, overall H(2)O(2) scavenging capacity is lower in RG and WG fibers, whereas glutathione peroxidase activity, which is largely responsible for H(2)O(2) removal in mitochondria, is similar in all three muscle types. These findings suggest that type II myofibers, particularly type IIB, possess unique properties that potentiate mitochondrial superoxide production and/or release, providing a potential mechanism for the heterogeneous development of mitochondrial dysfunction in skeletal muscle.

  8. Potassium nickel(II gallium phosphate hydrate, K[NiGa2(PO43(H2O2

    Directory of Open Access Journals (Sweden)

    Simon J. Hibble

    2009-05-01

    Full Text Available The title compound, potassium nickel(II digallium tris(phosphate dihydrate, K[NiGa2(PO43(H2O2], was synthesized hydrothermally. The structure is constructed from distorted trans-NiO4(H2O2 octahedra linked through vertices and edges to GaO5 trigonal bipyramids and PO4 tetrahedra, forming a three-dimensional framework of formula [NiGa2(PO43(H2O2]−. The K, Ni and one P atom lie on special positions (Wyckoff position 4e, site symmetry 2. There are two sets of channels within the framework, one running parallel to the [10overline{1}] direction and the other parallel to [001]. These intersect, forming a three-dimensional pore network in which the water molecules coordinated to the Ni atoms and the K+ ions required to charge balance the framework reside. The K+ ions lie in a highly distorted environment surrounded by ten O atoms, six of which are closer than 3.1Å. The coordinated water molecules are within hydrogen-bonding distance to O atoms of bridging Ga—O—P groups.

  9. The Tunable Bandgap of AB-Stacked Bilayer Graphene on SiO2 with H2O Molecule Adsorption

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; GUO Qing; AO Zhi-Min; LIU Yan; WANG Wen-Bo; SHENG Kuang; YU Bin

    2011-01-01

    The atomic and electronic structures of AB-stacking bilayer graphene (BLG) in the presence of H2O molecules are investigated by density functional theory calculations.For free-standing BLG,the bandgap is opened to 0.101 eV with a single H2O molecule adsorbed on its surface.The perfectly suspended BLG is sensitive to H2O adsorbates,which break the BLG lattice symmetry and open an energy gap.While a single H2O molecule is adsorbed on the BLG surface with a SiO2 substrate,the bandgap widens to 0.363eV.Both the H2O molecule adsorption and the oxide substrate contribute to the BLG bandgap opening.The phenomenon is interpreted with the charge transfer process in 2D carbon nanostructures.With its demonstrated unique electron transport properties,graphene has becomes one of the research hot spots with great potential in replacing silicon for future-generation nanoscale electronic devices.[1-3]Among graphene derivatives,AB-stacking bilayer graphene (BLG) exhibits fantastic properties.For example,the IBM research group successfully demonstrated a BLG-based transistor with a working frequency from 24.7 to 100GHz and highlighted suppressed electronic noise in devices.[4-6] With one additional layer added on single-layer graphene,BLG has a completely different band structure.However,pristine BLG still suffers from the same zero-bandgap (Eg) issue as single-layer graphene,hampering the implementation of logic switch devices with sufficient onto-off current ratios.%The atomic and electronic structures of AB-stacking bilayer graphene (BLG) in the presence of H2O molecules are investigated by density functional theory calculations. For free-standing BLG, the bandgap is opened to 0.101 eV with a single H2O molecule adsorbed on its surface. The perfectly suspended BLG is sensitive to H2O adsorbates, which break the BLG lattice symmetry and open an energy gap. While a single H2O molecule is adsorbed on the BLG surface with a S1O2 substrate, the bandgap widens to 0.363eV. Both the H2O

  10. On the chemical behavior of C60 hosting H2O and other isoelectronic neutral molecules.

    Science.gov (United States)

    Galano, Annia; Pérez-González, Adriana; del Olmo, Lourdes; Francisco-Marquez, Misaela; León-Carmona, Jorge Rafael

    2014-08-01

    The density functional theory (DFT) was used to investigate the chemical behavior of C60 hosting neutral guest molecules (NGM). The deformed atoms in molecules (DAM) allowed identifying the regions of electron density depletion and accumulation. The studied NGM are CH4, NH3, H2O, and HF. Based on dipole moment and polarizabilities analyses it is predicted that the NGM@C60 should be more soluble in polar solvents than C60. The deformations on the surface electron density of the fullerenes explain this finding, which might be relevant for further applications of these systems. It was found that the intrinsic reactivity of studied NGM@C60 is only moderately higher than that of C60. This trend is supported by the global reactivity indexes and the frontier orbitals analyses. The free radical scavenging activity of the studied systems, via single electron transfer, was found to be strongly dependent on the chemical nature of the reacting free radical. The presence of the studied NGM inside the C60 influences only to some extent the reactivity of C60 toward free radicals. The distortion of the electron density on the C60 cage, caused by the NGM, is directly related to the electron withdrawing capacity of the later.

  11. Are there Helium-like Protonic States of Individual Water Molecules in Liquid H2O?

    CERN Document Server

    Mueller-Herold, Ulrich

    2015-01-01

    Are there indications that individual H2O molecules in liquid water can loose their bent structure, i.e. that the protons give up their rigid angular correlation and behave largely uncorrelated, similar to electrons in the ground-state of helium? In agreement with the two-state picture of liquid water this would allow for the thermal coexistence of tetraedrically coordinated and spherical water molecules in the liquid. In the Hooke-Calogero model of a confined triatomic of XY2-type it is shown that energetically low-lying zero orbital-momentum states, which are bent if unconfined can change to helium-like shape under increasing confinement strength f. For the respective states this occurs at different values for f. It turns out that at f = 2.79 a bent and a helium-like state can thermally coexist. In order to characterize more precisely 'helium-like' angular correlation a maximum entropy estimate for the marginal correlation of electrons in the helium ground state is given. KEY WORDS: Liquid water, molecular ...

  12. Isotopomer-selective spectra of a single intact H2O molecule in the Cs+(D2O)5H2O isotopologue: Going beyond pattern recognition to harvest the structural information encoded in vibrational spectra

    Science.gov (United States)

    Wolke, Conrad T.; Fournier, Joseph A.; Miliordos, Evangelos; Kathmann, Shawn M.; Xantheas, Sotiris S.; Johnson, Mark A.

    2016-02-01

    We report the vibrational signatures of a single H2O molecule occupying distinct sites of the hydration network in the Cs+(H2O)6 cluster. This is accomplished using isotopomer-selective IR-IR hole-burning on the Cs+(D2O)5(H2O) clusters formed by gas-phase exchange of a single, intact H2O molecule for D2O in the Cs+(D2O)6 ion. The OH stretching pattern of the Cs+(H2O)6 isotopologue is accurately recovered by superposition of the isotopomer spectra, thus establishing that the H2O incorporation is random and that the OH stretching manifold is largely due to contributions from decoupled water molecules. This behavior enables a powerful new way to extract structural information from vibrational spectra of size-selected clusters by explicitly identifying the local environments responsible for specific infrared features. The Cs+(H2O)6 structure was unambiguously assigned to the 4.1.1 isomer (a homodromic water tetramer with two additional flanking water molecules) from the fact that its computed IR spectrum matches the observed overall pattern and recovers the embedded correlations in the two OH stretching bands of the water molecule in the Cs+(D2O)5(H2O) isotopomers. The 4.1.1 isomer is the lowest in energy among other candidate networks at advanced (e.g., CCSD(T)) levels of theoretical treatment after corrections for (anharmonic) zero-point energy. With the structure in hand, we then explore the mechanical origin of the various band locations using a local electric field formalism. This approach promises to provide a transferrable scheme for the prediction of the OH stretching fundamentals displayed by water networks in close proximity to solute ions.

  13. Isotopomer-selective spectra of a single intact H2O molecule in the Cs(+)(D2O)5H2O isotopologue: Going beyond pattern recognition to harvest the structural information encoded in vibrational spectra.

    Science.gov (United States)

    Wolke, Conrad T; Fournier, Joseph A; Miliordos, Evangelos; Kathmann, Shawn M; Xantheas, Sotiris S; Johnson, Mark A

    2016-02-21

    We report the vibrational signatures of a single H2O molecule occupying distinct sites of the hydration network in the Cs(+)(H2O)6 cluster. This is accomplished using isotopomer-selective IR-IR hole-burning on the Cs(+)(D2O)5(H2O) clusters formed by gas-phase exchange of a single, intact H2O molecule for D2O in the Cs(+)(D2O)6 ion. The OH stretching pattern of the Cs(+)(H2O)6 isotopologue is accurately recovered by superposition of the isotopomer spectra, thus establishing that the H2O incorporation is random and that the OH stretching manifold is largely due to contributions from decoupled water molecules. This behavior enables a powerful new way to extract structural information from vibrational spectra of size-selected clusters by explicitly identifying the local environments responsible for specific infrared features. The Cs(+)(H2O)6 structure was unambiguously assigned to the 4.1.1 isomer (a homodromic water tetramer with two additional flanking water molecules) from the fact that its computed IR spectrum matches the observed overall pattern and recovers the embedded correlations in the two OH stretching bands of the water molecule in the Cs(+)(D2O)5(H2O) isotopomers. The 4.1.1 isomer is the lowest in energy among other candidate networks at advanced (e.g., CCSD(T)) levels of theoretical treatment after corrections for (anharmonic) zero-point energy. With the structure in hand, we then explore the mechanical origin of the various band locations using a local electric field formalism. This approach promises to provide a transferrable scheme for the prediction of the OH stretching fundamentals displayed by water networks in close proximity to solute ions.

  14. Isotopomer-selective spectra of a single intact H2O molecule in the Cs+(D2O)5H2O isotopologue: Going beyond pattern recognition to harvest the structural information encoded in vibrational spectra

    Energy Technology Data Exchange (ETDEWEB)

    Wolke, Conrad T.; Fournier, Joseph A.; Miliordos, Evangelos; Kathmann, Shawn M.; Xantheas, Sotiris S.; Johnson, Mark A.

    2016-02-21

    We report the vibrational signatures of a single H2O water molecule occupying distinct sites of the hydration network in the Cs+(H2O)6 cluster. This is accomplished using isotopomer selective IR-IR hole-burning on the Cs+(D2O)5(H2O) clusters formed by gas-phase exchange of a single, intact H2O molecule for D2O in the Cs+(D2O)6 ion. The OH stretching pattern of the Cs+(H2O)6 isotopologue is accurately recovered by superposition of the isotopomer spectra, thus establishing that the H2O incorporation is random and that the OH stretching manifold is largely due to contributions from decoupled water molecules. This behavior enables a powerful new way to extract structural information from vibrational spectra of size-selected clusters by explicitly identifying the local environments responsible for specific infrared features. The Cs+(H2O)6 structure was unambiguously assigned to the 4.1.1 isomer (a homodromic water tetramer with two additional flanking water molecules) from the fact that its computed IR spectrum matches the observed overall pattern and recovers the embedded correlations in the two OH stretching bands of the water molecule in the Cs+(D2O)5(H2O) isotopomers. The 4.1.1 isomer is the lowest in energy among other candidate networks at advanced (e.g., CCSD(T)) levels of theoretical treatment after corrections for (anharmonic) zero-point energy (ZPE). With the structure in hand, we then explore the mechanical origin of the various band locations using a local electric field formalism. This approach promises to provide a transferrable scheme for the prediction of the OH stretching fundamentals displayed by water networks in close proximity to solute ions.

  15. Peroxiredoxin I and II inhibit H2O2-induced cell death in MCF-7 cell lines.

    Science.gov (United States)

    Bae, Ji-Yeon; Ahn, Soo-Jung; Han, Wonshik; Noh, Dong-Young

    2007-07-01

    Apoptosis is known to be induced by direct oxidative damage due to oxygen-free radicals or hydrogen peroxide or by their generation in cells by the actions of injurious agents. Together with glutathione peroxidase and catalase, peroxiredoxin (Prx) enzymes play an important role in eliminating peroxides generated during metabolism. We investigated the role of Prx enzymes during cellular response to oxidative stress. Using Prx isoforms-specific antibodies, we investigated the presence of Prx isoforms by immunoblot analysis in cell lysates of the MCF-7 breast cancer cell line. Treatment of MCF-7 with hydrogen peroxide (H2O2) resulted in the dose-dependent expressions of Prx I and II at the protein and mRNA levels. To investigate the physiologic relevance of the Prx I and II expressions induced by H2O2, we compared the survivals of MCF10A normal breast cell line and MCF-7 breast cancer cell line following exposure to H2O2. The treatment of MCF10A with H2O2 resulted in rapid cell death, whereas MCF-7 was resistant to H2O2. In addition, we found that Prx I and II transfection enabled MCF10A cells to resist H2O2-induced cell death. These findings suggest that Prx I and II have important functions as inhibitors of cell death during cellular response to oxidative stress.

  16. Herschel -PACS observations of [OI] and H2O in Cha II

    CERN Document Server

    Riviere-Marichalar, P; Kamp, I; Vicente, S; Williams, J P; Barrado, D; Eiroa, C; Duchne, G; Montesinos, B; Mathews, G; Podio, L; Dent, W R F; Huélamo, N; Merín, B

    2014-01-01

    Gas plays a major role in the dynamical evolution of protoplanetary discs. Its coupling with the dust is the key to our understanding planetary formation. Studying the gas content is therefore a crucial step towards understanding protoplanetary discs evolution. Such a study can be made through spectroscopic observations of emission lines in the far-infrared, where some of the most important gas coolants emit, such as the [OI] 3P1-3 P2 transition at 63.18 microns. We aim at characterising the gas content of protoplanetary discs in the intermediate-aged Chamaeleon II (Cha II) star forming region. We also aim at characterising the gaseous detection fractions within this age range, which is an essential step tracing gas evolution with age in different star forming regions. We obtained Herschel-PACS line scan spectroscopic observations at 63 microns of 19 Cha II Class I and II stars. The observations were used to trace [OI] and o-H2O at 63 microns. The analysis of the spatial distribution of [OI], when extended, c...

  17. Advanced oxidation removal of hypophosphite by O3/H2O2 combined with sequential Fe(II) catalytic process.

    Science.gov (United States)

    Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Wang, Wei; Liu, Zekun; Gao, Yaguang; Zhou, Beili

    2017-08-01

    Elimination of hypophosphite (HP) was studied as an example of nickel plating effluents treatment by O3/H2O2 and sequential Fe(II) catalytic oxidation process. Performance assessment performed with artificial HP solution by varying initial pH and employing various oxidation processes clearly showed that the O3/H2O2─Fe(II) two-step oxidation process possessed the highest removal efficiency when operating under the same conditions. The effects of O3 dosing, H2O2 concentration, Fe(II) addition and Fe(II) feeding time on the removal efficiency of HP were further evaluated in terms of apparent kinetic rate constant. Under improved conditions (initial HP concentration of 50 mg L(-1), 75 mg L(-1) O3, 1 mL L(-1) H2O2, 150 mg L(-1) Fe(II) and pH 7.0), standard discharge (oxidation treatment favored the improvement of phosphorus removal due to the formation of more metal hydroxides. Moreover, as a comparison with lab-scale Fenton approach, the O3/H2O2─Fe(II) oxidation process had more competitive advantages with respect to applicable pH range, removal efficiency, sludge production as well as economic costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Oxidation of Alkenes with H2O2 by an in-Situ Prepared Mn(II)/Pyridine-2-carboxylic Acid Catalyst and the Role of Ketones in Activating H2O2

    NARCIS (Netherlands)

    Dong, Jia Jia; Saisaha, Pattama; Meinds, Tim G.; Alsters, Paul L.; Ijpeij, Edwin G.; van Summeren, Ruben P.; Mao, Bin; Fananas-Mastral, Martin; de Boer, Johannes W.; Hage, Ronald; Feringa, Ben L.; Browne, Wesley R.

    2012-01-01

    A simple, high yielding catalytic method for the multigram scale selective epoxidation of electron-rich alkenes using near-stoichiometric H2O2 under ambient conditions is reported. The system consists of a Mn(II) salt (

  19. Crystal structures of two decavanadates(V with pentaaquamanganese(II pendant groups: (NMe42[V10O28{Mn(H2O5}2]·5H2O and [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O

    Directory of Open Access Journals (Sweden)

    Maurício P. Franco

    2015-02-01

    Full Text Available Two heterometallic decavanadate(V compounds, bis(tetramethylammonium decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V pentahydrate, (Me4N2[V10O28{Mn(H2O5}2]·5H2O, A, and bis{[tris(hydroxymethylmethyl]ammonium} decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(IIdecavanadate(V dihydrate, [NH3C(CH2OH3]2[V10O28{Mn(H2O5}2]·2H2O, B, have been synthesized under mild reaction conditions in an aqueous medium. Both polyanions present two [Mn(OH25]2+ complex units bound to the decavanadate cluster through oxide bridges. In A, the decavanadate unit has 2/m symmetry, whereas in B it has twofold symmetry. Apart from this, the main differences between A and B rest on the organic cations, tetramethylammonium and [tris(hydroxymethylmethyl]ammonium, respectively, and on the number and arrangement of the water molecules of crystallization. In both compounds, the H atoms from the coordinating water molecules participate in extensive three-dimensional hydrogen-bonding networks, which link the cluster units both directly and through solvent molecules and, in B, through the `tris' cation hydroxyl groups. The cation in B also participates in N—H...O hydrogen bonds. A number of C—H...O interactions are also observed in both structures.

  20. The role of H2O and O2 molecules and phosphorus vacancies in the structure instability of phosphorene

    Science.gov (United States)

    Kistanov, Andrey A.; Cai, Yongqing; Zhou, Kun; Dmitriev, Sergey V.; Zhang, Yong-Wei

    2017-03-01

    The poor structural stability of phosphorene in air was commonly ascribed to humidity and oxygen molecules. Recent exfoliation of phosphorene in deoxygenated water promotes the need to re-examine the role of H2O and O2 molecules. Considering the presence of high population of vacancies in phosphorene, we investigate the interaction of H2O and O2 molecules with vacancy-contained phosphorene using first-principles calculations. In contrast to the common notion that physisorbed molecules tend to have a stronger adsorption at vacancy sites, we show that H2O has nearly the same adsorption energy at the vacancy site as that at the perfect one. Charge transfer analysis shows that O2 is a strong electron scavenger, which transfers the lone-pair electrons of the phosphorus atoms to the 2π * antibonding orbital of O2. As a result, the barrier for the O-O bond splitting to form O-P bonds is reduced from 0.81 eV at the perfect site to 0.59 eV at the defect site, leading to an about 5000 faster oxidizing rate at the defect site than at the perfect site at room temperature. Hence, our work reveals that the vacancy in phosphorene shows a stronger oxygen affinity than the perfect phosphorene lattice site. Structural degradation of phosphorene due to oxidization may occur rapidly at edges and grain boundaries where vacancies tend to agglomerate.

  1. Syntheses, crystal structures, and magnetic properties of the oxalato-bridged mixed-valence complexes (FeII(bpm)3]2[FeIII2(ox)5].8H2O and FeII(bpm)3Na(H2O)2Fe(ox)(3).4H2O (bpm = 2,2'-bipyrimidine).

    Science.gov (United States)

    Armentano, D; De Munno, G; Faus, J; Lloret, F; Julve, M

    2001-02-12

    The preparation and crystal structures of two oxalato-bridged FeII-FeIII mixed-valence compounds, [FeII(bpm)3]2[FeIII2(ox)5].8H2O (1) and FeII(bpm)3Na(H2O)2FeIII(ox)(3).4H2O (2) (bpm = 2,2'-bipyrimidine; ox = oxalate dianion) are reported here. Complex 1 crystallizes in the triclinic system, space group P1, with a = 10.998(2) A, b = 13.073(3) A, c = 13.308(3) A, alpha = 101.95(2) degrees, beta = 109.20(2) degrees, gamma = 99.89(2) degrees, and Z = 1. Complex 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 12.609(2) A, b = 19.670(5) A, c = 15.843(3) A, beta = 99.46(1) degrees, and Z = 4. The structure of complex 1 consists of centrosymmetric oxalato-bridged dinuclear high-spin iron(III) [Fe2(ox)5]2- anions, tris-chelated low-spin iron(II) [Fe(bpm)3]2+ cations, and lattice water molecules. The iron atoms are hexacoordinated: six oxygen atoms (iron(III)) from two bidentate and one bisbidentate oxalato ligands and six nitrogen atoms (iron(II)) from three bidentate bpm groups. The Fe(III)-O(ox) and Fe(II)-N(bpm) bond distances vary in the ranges 1.967(3)-2.099(3) and 1.967(4)-1.995(3) A, respectively. The iron(III)-iron(III) separation across the bridging oxalato is 5.449(2) A, whereas the shortest intermolecular iron(III)-iron(II) distance is 6.841(2) A. The structure of complex 2 consists of neutral heterotrinuclear Fe(bpm)2Na(H2O)2Fe(ox)3 units and water molecules of crystallization. The tris-chelated low-spin iron(II) ([Fe(bpm)3]2+) and high-spin iron(III) ([Fe(ox)3]3-) entities act as bidentate ligands (through two bpm-nitrogen and two oxalato-oxygen atoms, respectively) toward the univalent sodium cation, yielding the trinuclear (bpm)2Fe(II)-bpm-Na(I)-ox-Fe(III)(ox)2 complex. Two cis-coordinated water molecules complete the distorted octahedral surrounding of the sodium atom. The ranges of the Fe(II)-N(bpm) and Fe(III)-O(ox) bond distances [1.968(6)-1.993(5) and 1.992(6)-2.024(6) A, respectively] compare well with those observed in 1. The Na

  2. New iron(II) spin crossover coordination polymers [Fe(μ-atrz)3]X2·2H2O (X = ClO4¯, BF4¯) and [Fe(μ-atrz)(μ-pyz)(NCS)2]·4H2O with an interesting solvent effect.

    Science.gov (United States)

    Chuang, Yu-Chun; Liu, Chi-Tsun; Sheu, Chou-Fu; Ho, Wei-Lun; Lee, Gene-Hsiang; Wang, Chih-Chieh; Wang, Chih-Cheh; Wang, Yu

    2012-04-16

    A potential bridging triazole-based ligand, atrz (trans-4,4'-azo-1,2,4-triazole), is chosen to serve as building sticks and incorporated with a spin crossover metal center to form a metal organic framework. Coordination polymers of iron(II) with the formula [Fe(μ-atrz)(3)]X(2)·2H(2)O (where X = ClO(4)(-) (1·2H(2)O) and BF(4)(-) (2·2H(2)O)) in a 3D framework and [Fe(μ-atrz)(μ-pyz)(NCS)(2)]·4H(2)O (3·4H(2)O) in a 2D layer structure were synthesized and structurally characterized. The magnetic measurements of 1·2H(2)O and 2·2H(2)O reveal spin transitions near room temperature; that of 3 exhibits an abrupt spin transition at ~200 K with a wide thermal hysteresis, and the spin transition behavior of these polymers are apparently correlated with the water content of the sample. Crystal structures have been determined both at high spin and at low spin states for 1·2H(2)O, 2·2H(2)O, and 3·4H(2)O. Each iron(II) center in 1·2H(2)O and 2·2H(2)O is octahedrally coordinated with six μ-atrz ligands, which in turn links the other Fe center forming a strong three-dimensional (3D) network; counteranion and water molecules are located in the voids of the lattice. The FeN(6) octahedron of 3·4H(2)O is formed with two atrz, two pyrazine (pyz) ligands, and two NCS(-) ligands, where the ligands atrz and pyz are bridged between iron centers forming a 2D layer polymer. A zigzag chain of water molecules is found between the layers, and there is a distinct correlation between the thermal hysteresis with the amount of water molecules the exist in the crystal.

  3. Photodesorption of Ices II: H2O and D2O

    CERN Document Server

    Oberg, Karin I; Visser, Ruud; van Dishoeck, Ewine F

    2008-01-01

    Gaseous H2O has been detected in several cold astrophysical environments, where the observed abundances cannot be explained by thermal desorption of H2O ice or by H2O gas phase formation. These observations hence suggest an efficient non-thermal ice desorption mechanism. Here, we present experimentally determined UV photodesorption yields of H2O and D2O ice and deduce their photodesorption mechanism. The ice photodesorption is studied under ultra high vacuum conditions and at astrochemically relevant temperatures (18-100 K) using a hydrogen discharge lamp (7-10.5 eV), which simulates the interstellar UV field. The ice desorption during irradiation is monitored using reflection absorption infrared spectroscopy of the ice and simultaneous mass spectrometry of the desorbed species. The photodesorption yield per incident photon is identical for H2O and D2O and depends on both ice thickness and temperature. For ices thicker than 8 monolayers the photodesorption yield Y is linearly dependent on temperature due to i...

  4. Dihydroxo-bridged dimeric Cu(II) system containing sandwiched non-coordinating phenylacetate anion: Crystal structure, spectroscopic, anti-bacterial, anti-fungal and DNA-binding studies of [(phen)(H2O)Cu(OH)2Cu(H2O)(phen)]2L.6H2O: (HL = phenylacetic acid; phen = 1,10-phenanthroline)

    Science.gov (United States)

    Iqbal, Muhammad; Ali, Saqib; Tahir, Muhammad Nawaz; Shah, Naseer Ali

    2017-09-01

    This paper reports the synthesis, X-ray crystal structure, DNA-binding, antibacterial and antifungal studies of a rare dihydroxo-bridged dinuclear copper(II) complex including 1,10-phenanthroline (Phen) ligands and phenylacetate (L) anions, [Cu2(Phen)2(OH)2(H2O)2].2L.6H2O. Structural data revealed distorted square-pyramidal geometry for each copper(II) atom with the basal plane formed by the two nitrogen atoms of the phenantroline ligand and the oxygen atoms of two bridging hydroxyl groups. The apical positions are filled by the oxygen atom from a water molecule. This forms a centrosymmetric cationic dimer where the uncoordinated phenylacetate ligands serve to balance the electrical charge. The dimers interact by means of hydrogen bonds aided by the coordinated as well as uncoordinated water molecules and phenyl-acetate moieties in the crystal lattice. The binding ability of the complex with salmon sperm DNA was determined using cyclic voltammetry and absorption spectroscopy yielding binding constants 2.426 × 104 M-1 and 1.399 × 104 M-1, respectively. The complex was screened against two Gram-positive (Micrococcus luteus and Bacillus subtilis) and one Gram-negative (Escherichia coli) bacterial strains exhibiting significant activity against all the three strains. The complex exhibited significant, moderate and no activity against fungal strains Mucor piriformis, Helminthosporium solani and Aspergillus Niger, respectively. These preliminary tests indicate the competence of the complex towards the development of a potent biological drug.

  5. Silver(I diaquanickel(II catena-borodiphosphate(V hydrate, (Ag0.57Ni0.22Ni(H2O2[BP2O8]·0.67H2O

    Directory of Open Access Journals (Sweden)

    Hafid Zouihri

    2011-08-01

    Full Text Available The structure framework of the title compound, (Ag0.57Ni0.22Ni(H2O2[BP2O8]·0.67H2O, is the same as that of its recently published counterpart AgMg(H2O2[BP2O8]·H2O. In the title structure, the Ag, Ni, B and one O atom are located on special positions (sites symmetry 2. The structure consists of infinite borophosphate helical [BP2O8]3− ribbons, built up from alternate BO4 and PO4 tetrahedra arranged around the 65 screw axes. The vertex-sharing BO4 and PO4 tetrahedra form a spiral ribbon of four-membered rings in which BO4 and PO4 groups alternate. The ribbons are connected through slightly distorted NiO4(H2O2 octahedra, four O atoms of which belong to the phosphate groups. The resulting three-dimensional framework is characterized by hexagonal channels running along [001]. However, the main difference between the structures of these two compounds lies in the filling ratio of Wyckoff positions 6a and 6b in the tunnels. Indeed, in this work, the refinement of the occupancy rate of sites 6a and 6b shows that the first is occupied by water at 67% and the second is partially occupied by 56.6% of Ag and 21.6% of Ni. In the AgMg(H2O2[BP2O8]·H2O structure, these two sites are completely occupied by H2O and Ag+, respectively. The title structure is stabilized by O—H...O hydrogen bonds between water molecules and O atoms that are part of the helices.

  6. H2O in stellar atmospheres. II. ISO spectra of cool red giants and hydrostatic models

    Science.gov (United States)

    Aringer, B.; Kerschbaum, F.; Jörgensen, U. G.

    2002-12-01

    We present 26 ISO-SWS spectra taken from a sample of 13 M-type Semiregular, Lb and Mira variables and covering the wavelength range between 2.36 and 5 mu m at a medium resolution. All of the studied objects show intense water bands producing a deep absorption dip around 2.5 mu m. Features of CO, OH, SiO and CO2 are also visible. Using the new H2O linelist published in the first paper of this series and available opacity data for the other important molecules, we calculated a grid of hydrostatic MARCS atmospheres and the corresponding synthetic ISO-SWS spectra. Based on the comparison with these theoretical results the ISO observations can be divided into four classes. The first two groups include the spectra of the Semiregular (SRb) and Lb variables in our sample. For all of them the region between 2.36 and 4.2 mu m can be quite well reproduced by our hydrostatic models. Only the predicted SiO bands above 4 mu m are in some cases too strong which is due to known dynamical effects. Depending on the temperature (above or below 3000 K) of the atmosphere, which mainly determines the intensity of the water depression at 2.5 mu m, the spectra of the Semiregular and Lb variables fall into the first or second class. The third group consists of observations of Mira stars obtained around maximum light where the range between 2.36 and 4.2 mu m can be fitted with our MARCS models except for a strong emission bump appearing in the ISO-SWS data in the region of the SiO features and the slope very close to the short wavelength border. Finally, the last type of spectra corresponds to Mira variables during the phases around the minimum of their visual light curve. For this class the observed water absorption at 2.5 mu m is much more intense than in any hydrostatic atmosphere with a realistic choice of effective temperature and surface gravity. Thus, we conclude that dynamical models are needed to explain the ISO-SWS data of Mira stars. For all of the cooler objects from our sample

  7. Silver diaquacobalt(II catena-borodiphosphate(V hydrate, (Ag0.79Co0.11Co(H2O2[BP2O8]·0.67H2O

    Directory of Open Access Journals (Sweden)

    Hafid Zouihri

    2012-01-01

    Full Text Available The structure of the title compound, (Ag0.79Co0.11Co(H2O2[BP2O8]·0.67H2O is isotypic to that of its recently published counterparts AgMg(H2O2[BP2O8]·H2O and (Ag0.57Ni0.22Ni(H2O2[BP2O8]·0.67H2O. It consists of infinite borophosphate helical ribbons [BP2O8]3−, built up from alternate BO4 and PO4 tetrahedra arranged around the 65 screw axes. The vertex-sharing BO4 and PO4 tetrahedra form a spiral ribbon of four-membred rings in which BO4 and PO4 groups alternate. The ribbons are connected through slightly distorted CoO4(H2O2 octahedra whose four O atoms belong to the phosphate groups. The resulting three-dimensional framework is characterized by hexagonal channels running along [001] in which the remaining water molecules are located. The main difference between the Mg-containing and the title structure lies in the filling ratio of Wyckoff positions 6a and 6b in the tunnels. The refinement of the occupancy rate of the site 6a shows that it is occupied by water at 67%, while the refinement of that of the site 6b shows that this site is partially occupied by 78.4% Ag and 10.8% Co, for a total of 82.2%. The structure is stabilized by O—H...O hydrogen bonds between water molecules and O atoms that are part of the helices.

  8. Efficient removal of dyes in water using chitosan microsphere supported cobalt (II) tetrasulfophthalocyanine with H2O2.

    Science.gov (United States)

    Shen, Chensi; Song, Shufang; Zang, Lili; Kang, Xiaodong; Wen, Yuezhong; Liu, Weiping; Fu, Liusong

    2010-05-15

    A new efficient catalyst, CoTSPc@chitosan, was developed by immobilizing water soluble cobalt (II) tetrasulfophthalocyanine onto adsorbent chitosan microspheres covalently for the heterogeneous catalytic oxidation of C. I. Acid Red 73 with H(2)O(2). The result indicated that the COD removal and discoloration of C. I. Acid Red 73 made 55 and 95% respectively in the presence of CoTSPc@chitosan with H(2)O(2) in 4h. In addition, CoTSPc@chitosan-H(2)O(2) system could proceed efficiently in a relatively wide pH range and remain high catalytic activity after 6 reuse cycles. Furthermore, the adsorption study of CoTSPc@chitosan confirmed that chitosan was an outstanding support which contributed a lot to the removal reaction. In conclusion, the combination of adsorption process and catalytic oxidation made the CoTSPc@chitosan-H(2)O(2) system achieve a simple, efficiently and environmentally friendly water treatment. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  9. Peroxydisulfate activation by [RuII(tpy)(pic)(H2O)]+. Kinetic, mechanistic and anti-microbial activity studies.

    Science.gov (United States)

    Chatterjee, Debabrata; Banerjee, Priyabrata; Bose, Jagadeesh C K; Mukhopadhyay, Sudit

    2012-03-07

    The oxidation of [Ru(II)(tpy)(pic)H(2)O](+) (tpy = 2,2',6',2''-terpyridine; pic(-) = picolinate) by peroxidisulfate (S(2)O(8)(2-)) as precursor oxidant has been investigated kinetically by UV-VIS, IR and EPR spectroscopy. The overall oxidation of Ru(II)- to Ru(IV)-species takes place in a consecutive manner involving oxidation of [Ru(II)(tpy)(pic)H(2)O](+) to [Ru(III)(tpy)(pic)(OH)](+), and its further oxidation of to the ultimate product [Ru(IV)(tpy)(pic)(O)](+) complex. The time course of the reaction was followed as a function of [S(2)O(8)(2-)], ionic strength (I) and temperature. Kinetic data and activation parameters are interpreted in terms of an outer-sphere electron transfer mechanism. Anti-microbial activity of Ru(II)(tpy)(pic)H(2)O](+) complex by inhibiting the growth of Escherichia coli DH5α in presence of peroxydisulfate has been explored, and the results of the biological studies have been discussed in terms of the [Ru(IV)(tpy)(pic)(O)](+) mediated cleavage of chromosomal DNA of the bacteria.

  10. Structure and magnetic properties of a new single-molecule magnet [Mn11Fe1O12 (CH3COO)16(H2O)4] ·2CH3COOH·4H2O

    Institute of Scientific and Technical Information of China (English)

    Cao Hui-Bo; He Lun-Hua; Wang Fang-Wei

    2005-01-01

    A new single-molecule magnet [Mn11Fe1O12(CH3COO)16(H2O)4].2CH3COOH.4H2O (Mn11Fe1) has been synthesized. The structure has been studied by the single crystal x-ray diffraction. The difference of Jahn-Teller distortion between Fe3+ and Mn3+ ion reveals that Fe3+ ion substitutes for Mn3+ ion on the Mn(3) sites in the Mn12 skeleton.The temperature dependence of the magnetization gives a blocking temperature TB=1.9K for Mn11Fe1. Based on the magnetization process analysis of the crystal at T=2K, we suggest that Mn11Fe1 has the ground state with a total spin S= 11/2.

  11. Rotations and vibrations of water molecule inside the fullerene cage: infrared study of H2O@C60

    Science.gov (United States)

    Room, Toomas; Shugai, A.; Nagel, U.; Mamone, S.; Krachmalnicoff, A.; Whitby, R. J.; Levitt, M. H.; Nishida, T.; Murata, Y.; Lei, Xuegong; Li, Yongjun; Turro, N. J.

    2015-03-01

    Water is the second molecule after hydrogen what has been trapped inside the cage of a C60 molecule by the molucular surgery method. We studied isolated water molecule isotopologs H2O, D2O, and HDO in the solid phase at cryogenic temperatures using IR spectroscopy. The water molecule rotation transitions were observed in the THz and vibration-rotation transitions in the mid-IR range. The slow conversion between para and ortho water allowed us to record the time evolution of spectra and to separate ortho and para absorption lines of water. The similarity of the rotation spectrum of caged water to water in the gas phase indicates that water is free to rotate in the C60 cage even at temperature as low as 3 K. However, spectral lines show a splitting of about 0.5 meV what is not compatible with the icosahedral symmetry of C60. Different models (e.g. crystal field effects in solid C60, C60 cage distortions) will be discussed. This work was supported by institutional research funding IUT23-3 of the Estonian Ministry of Education and Research.

  12. DNA-Binding Study of Tetraaqua-bis(p-nitrobenzoatocobalt(II Dihydrate Complex: [Co(H2O4(p-NO2C6H4COO2]·2H2O

    Directory of Open Access Journals (Sweden)

    Hacali Necefoglu

    2007-06-01

    Full Text Available The interaction of [Co(H2O4(p-NO2C6H4COO2]. 2H2O with sheep genomicDNA has been investigated by spectroscopic studies and electrophoresis measurements.The interaction between cobalt(II p-nitrobenzoate and DNA has been followed by gelelectrophoresis while the concentration of the complex was increased from 0 to 14 mM.The spectroscopic study and electrophoretic experiments support the fact that the complexbinds to DNA by intercalation via p-nitrobenzoate into the base pairs of DNA. Themobility of the bands decreased as the concentration of complex was increased, indicatingthat there was increase in interaction between the metal ion and DNA.

  13. Identification of a (H2O)8 cluster in a supramolecular host of a charge transfer platinum(II) complex

    Indian Academy of Sciences (India)

    Sutanuva Mandal; Ipsita Chatterjee; Alfonso Castiñeirs; Sreebrata Goswami

    2014-09-01

    The chemical reaction of PtII(L1)Cl2 [L1 = 2-(phenylazo)pyridine] with a bidentate N,S-donor atom ligand, 2-phenylthioaniline, (HL2) in alkaline acetonitrile yielded a mixed ligand donor acceptor complex, [PtII(L1)(L2)−]Cl, [1]Cl. The complex has been characterized by using a host of physical methods: X-ray crystallography, nuclear magnetic resonance, cyclic voltammetry, absorption spectroscopy, electron paramagnetic resonance. The complex showed intense interligand charge transfer (ILCT) transition in the long wavelength region of UV-vis spectrum at 785 nm. The single-crystal X-ray structure of complex, [1]Cl·2.6H2O is reported. The cationic complex upon crystallization from aqueous methanol solvent produces an assembly of three dimensional (H2O)8 guest moiety within the host lattice of reference Pt-complex. The water assembly showed a unique type of aggregation of two trigonal pyramids hydrogen bonded with three chloride anions. The complex displayed two reversible responses at −0.34 and −1.05 V along with one irreversible anodic response at 0.91 V versus Ag/AgCl reference electrode. The redox processes are characterized by examination of EPR spectra of the electrogenerated complexes.

  14. Atomic Hydrogen Surrounded by Water Molecules, H(H2O)m, Modulates Basal and UV-Induced Gene Expressions in Human Skin In Vivo

    Science.gov (United States)

    Shin, Mi Hee; Park, Raeeun; Nojima, Hideo; Kim, Hyung-Chel; Kim, Yeon Kyung; Chung, Jin Ho

    2013-01-01

    Recently, there has been much effort to find effective ingredients which can prevent or retard cutaneous skin aging after topical or systemic use. Here, we investigated the effects of the atomic hydrogen surrounded by water molecules, H(H2O)m, on acute UV-induced responses and as well as skin aging. Interestingly, we observed that H(H2O)m application to human skin prevented UV-induced erythema and DNA damage. And H(H2O)m significantly prevented UV-induced MMP-1, COX-2, IL-6 and IL-1β mRNA expressions in human skin in vivo. We found that H(H2O)m prevented UV-induced ROS generation and inhibited UV-induced MMP-1, COX-2 and IL-6 expressions, and UV-induced JNK and c-Jun phosphorylation in HaCaT cells. Next, we investigated the effects of H(H2O)m on intrinsically aged or photoaged skin of elderly subjects. In intrinsically aged skin, H(H2O)m application significantly reduced constitutive expressions of MMP-1, IL-6, and IL-1β mRNA. Additionally, H(H2O)m significantly increased procollagen mRNA and also decreased MMP-1 and IL-6 mRNA expressions in photoaged facial skin. These results demonstrated that local application of H(H2O)m may prevent UV-induced skin inflammation and can modulate intrinsic skin aging and photoaging processes. Therefore, we suggest that modifying the atmospheric gas environment within a room may be a new way to regulate skin functions or skin aging. PMID:23637886

  15. Synthesis, characterisation and antimicrobial activity of copper(II) and manganese(II) complexes of coumarin-6,7-dioxyacetic acid (cdoaH2) and 4-methylcoumarin-6,7-dioxyacetic acid (4-MecdoaH2): X-ray crystal structures of [Cu(cdoa)(phen)2].8.8H(2)O and [Cu(4-Mecdoa)(phen)2].13H2O (phen=1,10-phenanthroline).

    Science.gov (United States)

    Creaven, Bernadette S; Egan, Denise A; Karcz, Dariusz; Kavanagh, Kevin; McCann, Malachy; Mahon, Mary; Noble, Andy; Thati, Bhumika; Walsh, Maureen

    2007-08-01

    Two novel coumarin-based ligands, coumarin-6,7-dioxyacetic acid (1) (cdoaH(2)) and 4-methylcoumarin-6,7-dioxyacetic acid (2) (4-MecdoaH(2)), were reacted with copper(II) and manganese(II) salts to give [Cu(cdoa)(H(2)O)(2)].1.5H(2)O (3), [Cu(4-Mecdoa)(H(2)O)(2)] (4), [Mn(cdoa)(H(2)O)(2)] (5) and [Mn(4-Mecdoa)(H(2)O)(2)].0.5H(2)O (6). The metal complexes, 3-6, were characterised by elemental analysis, IR and UV-Vis spectroscopy, and magnetic susceptibility measurements and were assigned a polymeric structure. 1 and 2 react with Cu(II) in the presence of excess 1,10-phenanthroline (phen) giving [Cu(cdoa)(phen)(2)].8.8H(2)O (7) and [Cu(4-Mecdoa)(phen)(2)].13H(2)O (8), respectively. The X-ray crystal structures of 7 and 8 confirmed trigonal bipyramidal geometries, with the metals bonded to the four nitrogen atoms of the two chelating phen molecules and to a single carboxylate oxygen of the dicarboxylate ligand. The complexes were screened for their antimicrobial activity against a number of microbial species, including methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Candida albicans. The metal-free ligands 1 and 2 were active against all of the microbes. Complexes 3-6 demonstrated no significant activity whilst the phen adducts 7 and 8 were active against MRSA (MIC(80)=12.1microM), E. coli (MIC(80)=14.9microM) and Patonea agglumerans (MIC(80)=12.6microM). Complex 7 also demonstrated anti-Candida activity (MIC(80)=22microM) comparable to that of the commercially available antifungal agent ketoconazole (MIC(80)=25microM).

  16. Secondary ion emission from CO2-H2O ice irradiated by energetic heavy ions: Part II: Analysis-search for organic ions

    Science.gov (United States)

    Ponciano, C. R.; Farenzena, L. S.; Collado, V. M.; da Silveira, E. F.; Wien, K.

    2005-06-01

    Secondary ion mass spectrometry is used to investigate ion emission from a frozen-gas mixture of CO2 and H2O (T = 80-90 K) bombarded by MeV nitrogen ions and by 252Cf fission fragments. The aim of the experiment is to detect organic molecules, produced in the highly excited material around the nuclear track, which appear as ions in the flux of sputtered particles. Part I of the present work [L.S. Farenzena, V.M. Collado, C.R Ponciano, E.F. da Silveira, K. Wien. Int. J. Mass Spectrom. 243 (2005) 85-93] described the method and presented the time-of-flight mass spectra; a list of the CO2 specific and H2O specific reaction products was provided. In Part II, the peaks of the TOF mass spectra are analyzed. Projectile-ice direct coulomb interaction leads to the production in the track of the H+, C+, O+, O2+, CO+ and CO2+ primarily ions, which react in the highly energized nuclear track plasma mainly with CO2 and H2O or H2CO3. The positive molecular hybrid ions formed are identified as organic species like COH+, COOH+, CHn = 1-3+, Hn = 1,2COOH+ and cluster ions. Similarly, the negative primarily ions O- and OH- formed by electron capture produce negative hybrid ions such as (CO2)nOH-, the four ions (CO4Hm = 0-3)- and the corresponding cluster ions. By far, most of the molecular ions have been formed by one-step reactions; exceptions are eventually the CO4Hm- ions created by a reaction between CO3- and water molecules. An intense mass line corresponding to HCO3+ has been observed, but not the one due to formaldehyde ion. Weak signals of ionic ketene, hydrogen peroxide and carbonic acid were seen.

  17. Librational modes of the water molecules in barium and strontium halide monohydrates, MX 2 · 1H 2O (M = Ba, Sr; X = Cl, Br, I)

    Science.gov (United States)

    Lutz, H. D.; Christian, H.

    1983-09-01

    The IR and Raman spectra of the isotypic alkaline earth halide monohydrates, MX 2 · 1H 2O, with M = Sr, Ba and X = Cl, Br, I, and of deuterated samples are presented for the range 200-700 cm -1 and discussed in terms of normal modes, assignment, coupling, correlation with structure data, and temperature dependence of both the H 2O (D 2O) and the HDO librational modes. The normal modes of the out-of-plane librations of HDO molecules are of the wagging and twisting type rather than H and D out-of-plane vibrations [4], at least for water molecules with C2v or nearly C2v symmetry. Thus the observed H 2O/HDO isotopic shifts can be used as a criterion for assigning the H 2O librations. The librational modes of the halide monohydrates (with tetrahedrally coordinated water oxygen atoms) are found in the order ν Rγ ≫ ν Rt ≫ ν Rr. The intensities of the IR and Raman spectra are in the order Rγ ≫ Rr ≫ Rt (or ˜ Rt in the case of strongly distorted H 2O molecules) and Rt ≫ Rr ≫ Rγ, respectively. Correlations of the H 2O librational modes with structural or bonding data are restricted by frequency shifts due to vibrational coupling and by the fact that the oxygen and the hydrogen atoms of the water molecules are generally affected in a different manner by bond interactions. However, in the case of the twisting vibrations, there are clear correlations with both the size of the metal ions, i.e. increase of ν Rt with decreasing size, and the intermolecular bonding of the hydrogen atoms, as shown by the OH stretching frequencies, i.e. increase of ν Rt with decreasing ν OH.

  18. Keck II Observations of Hemispherical Differences in H2O2 on Europa

    CERN Document Server

    Hand, Kevin P; 10.1088/2041-8205/766/2/L21

    2013-01-01

    We present results from Keck II observations of Europa over four consecutive nights using the near-infrared spectrograph (NIRSPEC). Spectra were collected in the 3.14--4.0 micron range, allowing detection and monitoring of the 3.5 micron feature due to hydrogen peroxide. Galileo Near-Infrared Spectrometer (NIMS) results first revealed hydrogen peroxide on Europa in the anti-jovian region of the leading hemisphere at an abundance of 0.13+/-0.07% by number abundance relative to water. We find comparable results for the two nights over which we observed the leading hemisphere. Significantly, we observed a small amount of hydrogen peroxide (~0.04%) during observations of Europa's anti- and sub-Jovian hemispheres. Almost no hydrogen peroxide was detected during observations of just the trailing hemisphere. We conclude that the Galileo observations likely represent the maximum hydrogen peroxide concentration, the exception potentially being the cold water ice regions of the poles, which are not readily observable f...

  19. Holo- and hemidirected lead(II) in the polymeric [Pb(4)(mu-3,4-TDTA)2(H2O)2]*4H2O complex. N,N,N',N'-tetraacetate ligands derived from o-phenylenediamines as sequestering agents for lead(II).

    Science.gov (United States)

    Sanchiz, Joaquín; Esparza, Pedro; Villagra, Diego; Domínguez, Sixto; Mederos, Alfredo; Brito, Felipe; Araujo, Lorena; Sánchez, Agustin; Arrieta, Juan Manuel

    2002-11-18

    The coordinating ability of the ligands 3,4-toluenediamine-N,N,N',N'-tetraacetate (3,4-TDTA), o-phenylenediamine-N,N,N',N'-tetraacetate (o-PhDTA), and 4-chloro-1,2-phenylenediamine-N,N,N',N'-tetraacetate (4-Cl-o-PhDTA) (H4L acids) toward lead(II) is studied by potentiometry (25 degrees C, I = 0.5 mol x dm(-3) in NaClO4), UV-vis spectrophotometry, and 207Pb NMR spectrometry. The stability constants of the complex species formed were determined. X-ray diffraction structural analysis of the complex [Pb4(mu-3,4-TDTA)4(H2O)2]*4H2O (1) revealed that 1 has a 2-D structure. The layers are built up by the polymerization of centrosymmetric [Pb4L2(H2O)2] tetranuclear units. The neutral layers have the aromatic rings of the ligands pointing to the periphery, whereas the metallic ions are located in the central part of the layers. In compound 1, two types of six-coordinate lead(II) environments are produced. The Pb(1) is coordinated to two nitrogen atoms and four carboxylate oxygens from the ligand, whereas Pb(2) has an O6 trigonally distorted octahedral surrounding. The lead(II) ion is surrounded by five carboxylate oxygens and a water molecule. The carboxylate oxygens belong to four different ligands that are also joined to four other Pb(1) ions. The selective uptake of lead(II) was analyzed by means of chemical speciation diagrams as well as the so-called conditional or effective formation constants K(Pb)eff. The results indicate that, in competition with other ligands that are strong complexing agents for lead(II), our ligands are better sequestering agents in acidic media.

  20. Photocurrent enhanced dye-sensitized solar cells based on TiO2 loaded K6SiW11O39Co(II)(H2O)·xH2O photoanode materials.

    Science.gov (United States)

    Li, Liang; Yang, YuLin; Fan, RuiQing; Wang, Xin; Zhang, Qingming; Zhang, Lingyun; Yang, Bin; Cao, Wenwu; Zhang, Wenzhi; Wang, Yazhen; Ma, Liqun

    2014-01-28

    Through loading of TiO2 on the surface of K6SiW11O39Co(II)(H2O)·xH2O (SiW11Co), a novel photoanode material has been created for dye-sensitized solar cells (DSSC). The absorbing band as well as photoelectricity response range of TiO2@SiW11Co is extended to the visible range. In addition, the absorption in the UV range is enhanced notably compared with P25 (raw TiO2). More importantly, the recombination of the TiO2 network is avoided. TiO2@SiW11Co is mixed with P25 powder (wt ∼1 : 1) to assemble dye-sensitized (N719) solar cells, which exhibit a short-circuit photocurrent density as high as 18.05 mA cm(-2), which is 64% higher than blank samples under the standard AM1.5G global solar irradiation. In addition, the mechanisms for SiW11Co in DSSC are proposed.

  1. 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].

    Science.gov (United States)

    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

  2. Interaction between H2O, N2, CO, NO, NO2 and N2O molecules and a defective WSe2 monolayer.

    Science.gov (United States)

    Ma, Dongwei; Ma, Benyuan; Lu, Zhiwen; He, Chaozheng; Tang, Yanan; Lu, Zhansheng; Yang, Zongxian

    2017-09-18

    In this study, the interaction between gas molecules, including H2O, N2, CO, NO, NO2 and N2O, and a WSe2 monolayer containing an Se vacancy (denoted as VSe) has been theoretically studied. Theoretical results show that H2O and N2 molecules are highly prone to be physisorbed on the VSe surface. The presence of the Se vacancy can significantly enhance the sensing ability of the WSe2 monolayer toward H2O and N2 molecules. In contrast, CO and NO molecules highly prefer to be molecularly chemisorbed on the VSe surface with the non-oxygen atom occupying the Se vacancy site. Furthermore, the exposed O atoms of the molecularly chemisorbed CO or NO can react with additional CO or NO molecules, to produce C-doped or N-doped WSe2 monolayers. The calculated energies suggest that the filling of the CO or NO molecule and the removal of the exposed O atom are both energetically and dynamically favorable. Electronic structure calculations show that the WSe2 monolayers are p-doped by the CO and NO molecules, as well as the C and N atoms. However, only the NO molecule and N atom doped WSe2 monolayers exhibit significantly improved electronic structures compared with VSe. The NO2 and N2O molecules will dissociate directly to form an O-doped WSe2 monolayer, for which the defect levels due to the Se vacancy can be completely removed. The calculated energies suggest that although the dissociation processes for NO2 and N2O molecules are highly exothermic, the N2O dissociation may need to operate at an elevated temperature compared with room temperature, due to its large energy barrier of ∼1 eV.

  3. Near-Infrared Band Strengths of Molecules Diluted in N2 and H2O Ice Mixtures Relevant to Interstellar and Planetary Ices

    Science.gov (United States)

    Richey, Christina Rae; Gerakines, P.A.

    2012-01-01

    The relative abundances of ices in astrophysical environments rely on accurate laboratory measurements of physical parameters, such as band strengths (or absorption intensities), determined for the molecules of interest in relevant mixtures. In an extension of our previous study on pure-ice samples, here we focus on the near-infrared absorption features of molecules in mixtures with the dominant components of interstellar and planetary ices, H2O and N2. We present experimentally measured near-infrared spectral information (peak positions, widths, and band strengths) for both H2O- and N2-dominated mixtures of CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane), and NH3 (ammonia). Band strengths were determined during sample deposition by correlating the growth of near-infrared features (10,000-4000 per centimeter, 1-2.5 micrometers) with better-known mid-infrared features (4000-400 per centimeter, 2.5-25 micrometers) at longer wavelengths.

  4. Direct functionalization of M-C (M = Pt(II), Pd(II)) bonds using environmentally benign oxidants, O2 and H2O2.

    Science.gov (United States)

    Vedernikov, Andrei N

    2012-06-19

    Atom economy and the use of "green" reagents in organic oxidation, including oxidation of hydrocarbons, remain challenges for organic synthesis. Solutions to this problem would lead to a more sustainable economy because of improved access to energy resources such as natural gas. Although natural gas is still abundant, about a third of methane extracted in distant oil fields currently cannot be used as a chemical feedstock because of a dearth of economically and ecologically viable methodologies for partial methane oxidation. Two readily available "atom-economical" "green" oxidants are dioxygen and hydrogen peroxide, but few methodologies have utilized these oxidants effectively in selective organic transformations. Hydrocarbon oxidation and C-H functionalization reactions rely on Pd(II) and Pt(II) complexes. These reagents have practical advantages because they can tolerate moisture and atmospheric oxygen. But this tolerance for atmospheric oxygen also makes it challenging to develop novel organometallic palladium and platinum-catalyzed C-H oxidation reactions utilizing O(2) or H(2)O(2). This Account focuses on these challenges: the development of M-C bond (M = Pt(II), Pd(II)) functionalization and related selective hydrocarbon C-H oxidations with O(2) or H(2)O(2). Reactions discussed in this Account do not involve mediators, since the latter can impart low reaction selectivity and catalyst instability. As an efficient solution to the problem of direct M-C oxidation and functionalization with O(2) and H(2)O(2), this Account introduces the use of facially chelating semilabile ligands such as di(2-pyridyl)methanesulfonate and the hydrated form of di(2-pyridyl)ketone that enable selective and facile M(II)-C(sp(n)) bond functionalization with O(2) (M = Pt, n = 3; M = Pd, n = 3 (benzylic)) or H(2)O(2) (M = Pd, n = 2). The reactions proceed efficiently in protic solvents such as water, methanol, or acetic acid. With the exception of benzylic Pd(II) complexes, the

  5. Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H2O)3

    Institute of Scientific and Technical Information of China (English)

    GAO Dong-Zhao; WANG Shu-Ping; CHEN Jin; LI Li-Cun; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping

    2006-01-01

    A new Zn(II) nitronyl nitroxide complex [Zn(NIT4Py)(PDA)(H2O)3] (NIT4Py = 2-(4'-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2PDA = pyridine-2,5-dicarboxylic acid) has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.881(8), b = 7.356(4), c = 18.857(9)(A), β= 108.616(6)°, V = 2219.1(19)(A)3, C19H25N4O9Zn, Mr = 518.80, Dc = 1.553 g/cm3, μ(MoKα) = 1.165 mm-1, F(000) = 1076, Z = 4, the final R = 0.0269 and wR = 0.0715 for 3193 observed reflections with I > 2σ(I). The complex exists as discrete mononuclear molecules and the zinc(II) ion is six-coordinated with one radical ligand (NIT4Py), one bidentate pyridine-2,5-dicarboxylate anion and three water molecules. A three-dimensional network structure is formed through the intermolecular interactions.

  6. Formation of Polyatomic Molecules on a Dust-Grain Analogue Using Superthermal H and O Atoms: Relevance to Discovery of Circumstellar H2O by Herschel

    Science.gov (United States)

    Madzunkov, S. M.; Chutjian, A.; Darrach, M. R.; MacAskill, J. A.; Ehrenfreund, P.; Vidali, G.

    2011-05-01

    Carbon dioxide (CO2), formaldehyde (H2CO), methanol (CH3OH), ethanol (CH3CH2OH), and formic acid (HCOOH) have been formed in separate measurements involving collisions of superthermal beams of H(2S) atoms and O(3P) atoms with CO and CH4 molecules adsorbed on a gold surface at 4.8K. The collision products are detected using temperature-programmed desorption and mass spectrometry. Identification of the species is made through use of the Metropolis random-walk algorithm as constrained by the fractionation patterns. The relevance of this work to the recent discovery of H2O at the star IRC+10216 by PACS-SPIRE/Herschel will be discussed in terms of the grain-mediated reaction O(3P, 1-5 eV) + H2(grain) → H2O(grain), in which the O(3P) arises from stellar UV photodissociation.

  7. Mechanism of Alkene, Alkane, and Alcohol Oxidation with H2O2 by an in Situ Prepared Mn-II/Pyridine-2-carboxylic Acid Catalyst

    NARCIS (Netherlands)

    Saisaha, Pattama; Dong, Jia Jia; Meinds, Tim G.; de Boer, Johannes W.; Hage, Ronald; Mecozzi, Francesco; Kasper, Johann B.; Browne, Wesley R.

    2016-01-01

    The oxidation of alkenes, alkanes, and alcohols with H2O2 is catalyzed efficiently using an in situ prepared catalyst comprised of a MnII salt and pyridine-2-carboxylic acid (PCA) together with a ketone in a wide range of solvents. The mechanism by which these reactions proceed is elucidated, with a

  8. Partial-Redox-Promoted Mn Cycling of Mn(II)-Doped Heterogeneous Catalyst for Efficient H2O2-Mediated Oxidation.

    Science.gov (United States)

    Li, Hai-Tao; Gao, Qiang; Han, Bo; Ren, Zheng-Hui; Xia, Kai-Sheng; Zhou, Cheng-Gang

    2017-01-11

    The development of a heterogeneous catalyst with high catalytic activity and durability for H2O2-mediated oxidation is one of the most important industrial and environmental issues. In this study, a Mn(II)-doped TiO2 heterogeneous catalyst was developed for H2O2-mediated oxidation. The TiO2 substrate-dependent partial-redox behavior of Mn was identified on the basis of our density functional theory simulations. This unique redox cycle was induced by a moderate electron transfer from Ti to Mn, which compensated for the electron loss of Mn and finally resulted in a high-efficiency cycling of Mn between its oxidized and reduced forms. In light of the theoretical results, a Mn(II)-doped TiO2 composite with well-defined morphology and large surface area (153.3 m(2) g(-1)) was elaborately fabricated through incorporating Mn(II) ions into a TiO2 nanoflower, and further tested as the catalyst for oxidative degradation of organic pollutants in the presence of H2O2. Benefiting from the remarkable textural features and excellent Mn cycling property, this composite exhibited superior catalytic performance for organic pollutant degradation. Moreover, it could retain 98.40% of its initial activity even in the fifth cycle. Our study provides an effective strategy for designing heterogeneous catalytic systems for H2O2-mediated oxidations.

  9. PRODUCTION OF IRON(II SULPHATE(FeSO4.7H2 O FROM RED-MUD

    Directory of Open Access Journals (Sweden)

    Nihat TINKILIÇ

    1996-02-01

    Full Text Available The red-mud obtained during the production of aluminium from bauxite as a by-product contains valuable materials such as Fe, Al, Na,V, Ti etc. In this study, red-mud was dissolved with H2 SO4 and converted to FeSO4.7H2 O by 86 % efficiency. The optimum converting conditions were found as heating for three hours at 170o C. The red-mud is not suitable for the production of pig iron because, it hasn't got enough iron contents(38.57 per cent Fe2 O3. We concluded that, the red-mud can be used in production of FeSO4.7H2 O.

  10. Nucleobases and Prebiotic Molecules in Organic Residues Produced from the Ultraviolet Photo-Irradiation of Pyrimidine in NH3 and H2O+NH3 Ices

    Science.gov (United States)

    Nuevo, Michel; Milam, Stefanie N.; Sandford, Scott

    2012-01-01

    Although not yet identified in the interstellar medium (ISM), N-heterocycles including nucleobases the information subunits of DNA and RNA are present in carbonaceous chondrites, which indicates that molecules of biological interest can be formed in non-terrestrial environments via abiotic pathways. Recent laboratory experiments and ab-initio calculations have already shown that the irradiation of pyrimidine in pure H2O ices leads to the formation of a suite of oxidized pyrimidine derivatives, including the nucleobase uracil. In the present work, NH3:pyrimidine and H2O:NH3:pyrimidine ice mixtures with different relative proportions were irradiated with UV photons under astrophysically relevant conditions. Liquid- and gas-chromatography analysis of the resulting organic residues has led to the detection of the nucleobases uracil and cytosine, as well as other species of prebiotic interest such as urea and small amino acids. The presence of these molecules in organic residues formed under abiotic conditions supports scenarios in which extraterrestrial organics that formed in space and were subsequently delivered to telluric planets via comets and meteorites could have contributed to the inventory of molecules that triggered the first biological reactions on their surfaces.

  11. Dissociation and suppressed ionization of H2O molecules embedded in He clusters: The role of the cluster as a cage

    Science.gov (United States)

    Kanaev, A. V.; Museur, L.; Laarmann, T.; Monticone, S.; Castex, M. C.; von Haeften, K.; Möller, T.

    2001-12-01

    Electronic structure and energy transfer in H2O doped HeN clusters (N≈104 is studied with photoexcitation in the spectral range of 140-40 nm (9-30 eV). The reaction dynamics is investigated by fluorescence of neutral OH* and H* and ionic H2O+* fragments. The rotational temperature of embedded water molecules has been estimated from the 124 nm line shape (3pa1C1B1←1b1 X˜ 1A1 transition). Two different temperatures (T1⩽5 K and T2≈30 K) have been found. We propose that the lower temperature (T1) is due to completely thermalized water molecules trapped inside helium clusters, while the warmer molecules (T2) are formed if they are first captured by helium clusters but then leave the clusters again. Predissociation of H2,/SUBO with excitation below the ionization limit (λexc>100 nm) is found to be unaffected by the cluster environment. On the other hand, the ionization (λexc<100 nm) seems to be suppressed inside helium clusters in favor of the fragmentation into neutral products.

  12. Hydrothermal syntheses and single crystal structural characterization of M(H2O)6(OPTA)2 [M = Co(II), Ni(II), Zn(II); OPTA = 1-oxopyridinium-2-thioacetato

    Indian Academy of Sciences (India)

    S Kumaresan; P Ramadevi; R D Walsh; A McAneny; C H Lake

    2006-05-01

    A new class of compounds of the family M(H2O)6(OPTA)2 (where M = Co(II), Ni(II), and Zn(II); OPTA = 1-oxopyridinium-2-thioacetato) was prepared from the appropriate metal acetates, 1-oxopyridinium-2-thioacetic acid (OPTAH), and potassium hydroxide in hydrothermal media and structurally characterized. The structure is constructed from M(H2O)$_{6}^{2+}$ and two anions of OPTAH (C7H6NO3S) linked through hydrogen bonding into an extended network.

  13. Theoretical calculation of oxygen equilibrium isotope fractionation factors involving various NOy molecules, radOH, and H2O and its implications for isotope variations in atmospheric nitrate

    Science.gov (United States)

    Walters, Wendell W.; Michalski, Greg

    2016-10-01

    The oxygen stable isotope composition (δ18O) of nitrogen oxides [NOx = nitric oxide (NO) + nitrogen dioxide (NO2)] and their oxidation products (NOy = NOx + nitric acid (HNO3) + particulate nitrate (p-NO3-) + nitrate radical (NO3) + dinitrogen pentoxide (N2O5) + nitrous acid (HONO) + …) have been shown to be a useful tool for inferring the proportion of NOx that is oxidized by ozone (O3). However, isotopic fractionation processes may have an influence on δ18O of various NOy molecules and other atmospheric O-bearing molecules pertinent to NOx oxidation chemistry. Here we have evaluated the impacts of O isotopic exchange involving NOy molecules, the hydroxyl radical (radOH), and water (H2O) using reduced partition function ratios (xβ) calculated by hybrid density functional theory. Assuming atmospheric isotopic equilibrium is achieved between NO and NO2 during the daytime, and NO2, NO3, and N2O5 during the nighttime, δ18O-δ15N compositions were predicted for the major atmospheric nitrate formation pathways using our calculated exchange fractionation factors and isotopic mass-balance. Our equilibrium model predicts that various atmospheric nitrate formation pathways, including NO2 + radOH → HNO3, N2O5 + H2O + surface → 2HNO3, and NO3 + R → HNO3 + Rrad will yield distinctive δ18O-δ15N compositions. Our calculated δ18O-δ15N compositions match well with previous atmospheric nitrate measurements, and will potentially help better understand the role oxidation chemistry plays on the N and O isotopic composition of atmospheric nitrate.

  14. Theoretical study of the binding energy of a methane molecule in a (H2O)20 dodecahedral cage.

    Science.gov (United States)

    Deible, Michael J; Tuguldur, Odbadrakh; Jordan, Kenneth D

    2014-07-17

    The interaction energy of a methane molecule encapsulated in a dodecahedral water cage is calculated using the MP2, MP2C, various dispersion-corrected DFT, and diffusion Monte Carlo (DMC) methods. The MP2, MP2C, and DMC methods give binding energies of -5.04, -4.60, and -5.3 ± 0.5 kcal/mol, respectively. In addition, the two- and three-body contributions are evaluated using the DFT, MP2, and CCSD(T) methods. All of the DFT methods considered appreciably overestimate the magnitude of the three-body contribution to the interaction energy. The two- and three-body energies are further analyzed by use of symmetry-adapted perturbation theory (SAPT) which allows decomposition into electrostatics, exchange, induction, and dispersion contributions. The SAPT calculations reveal that the induction, dispersion, and exchange three-body contributions to the methane-cage binding energy are all sizable, with the net three-body contribution to the binding energy being about 1 kcal/mol.

  15. Tritium Labeled Gentamicin C: II.- Bioradiactive Degradation Products of Gentamicin by Catalytic H2O-3H Exchange Reaction; Getamicina C Tritiada: II.- Productos de Degradacion Radiactivos y Bioactivos en el Intercambio Catalitico con H2O-3H

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, C.; Diaz, A.; Paz, D.; Jimeno, M. L.

    1992-07-01

    The main bio radioactive degradation products from catalytic hydrogen exchange of gentamicin C, (C1 + C2 + Cla) in basic form, are generated by N-demethylation in 3{sup -}N and 6-N positions. Their structures were confirmed by 1HNMR and 13CNMR. These derivatives were fractionated by chromatography on silica gel. Antibacterial activities were similar to those of the parent antibiotics. Tritium exchange, under vacuum or nitrogen, is highly increased (4:1) when gentamicin are in basic form. In contrast with gentamicin sulfate, hydrolytic sub products as gramine, genta mines, garosamine and purpurosamines are practically absent. To properly optimize the exchange process, the composition of the gentamicin C complex must be taken into account. The exchange decreases in the order C2 > C1> Cla. Because of 6'-N-demethyl gentamicin C1 is C2, the radiochemical yield of C2 appears enhanced in the H2O-3H exchange of a mixture of them. Radioactivity distribution among the components and subunits of these three gentamicin were studied by strong and mild hydrolysis, and by methanolysis. (Author) 18 refs.

  16. Structural study of CH4, CO2 and H2O clusters containing from several tens to several thousands of molecules

    Science.gov (United States)

    Torchet, G.; Farges, J.; de Feraudy, M. F.; Raoult, B.

    Clusters are produced during the free jet expansion of gaseous CH4, CO2 or H2O. For a given stagnation temperature To, the mean cluster size is easily increased by increasing the stagnation pressure p0. On the other hand, the cluster temperature does not depend on stagnation conditions but mainly on properties of the condensed gas. An electron diffraction analysis provides information about the cluster structure. Depending on whether the diffraction patterns exhibit crystalline lines or not, the structure is worked out either by using crystallographic methods or by constructing cluster models. When they contain more than a few thousand molecules, clusters show a crystalline structure identical to that of one phase, namely, the cubic phase, known in bulk solid: plastic phase (CH4), unique solid phase (CO2) or metastable cubic phase (H2O). When decreasing the cluster size, the studied compounds behave quite differently: CO2 clusters keep the same crystalline structure, CH4 clusters show the multilayer icosahedral structure wich has been found in rare gas clusters, and H2O clusters adopt a disordered structure different from the amorphous structures of bulk ice. Des agrégats sont produits au cours de la détente en jet libre des gaz CH4, CO2 ou H2O. Pour une température initiale donnée To, on accroît facilement la taille moyenne des agrégats en augmentant la pression initiale po . Par contre, la température des agrégats dépend principalement des propriétés du gaz condensé. Une analyse par diffraction électronique permet l'étude de la structure des agrégats. Selon que les diagrammes de diffraction contiennent ou non des raies cristallines, on a recours soit à des méthodes cristallographiques soit à la construction de modèles d'agrégats. Lorsqu'ils renferment plus de quelques milliers de molécules, les agrégats adoptent la structure cristalline de l'une des phases connues du solide massif et plus précisément la phase cubique : phase plastique pour

  17. Synthesis and Structure of a New Copper(II)Complex Cu(C13H9N3O2Br)2·H2O

    Institute of Scientific and Technical Information of China (English)

    张修堂; 詹晓平; 吴鼎铭; 杨文斌; 卢灿忠

    2002-01-01

    The new copper(II) complex Cu(C13H9N3O2Br)2@H2O (N-(2-hydroxy-5-bromo- benzoyl)-N?-(picolinylidene)hydrazine is abbreviated as HL ) was obtained from the refluxing solution of Cu(CH3COO)2H2O and HL in the ethanol-N, N-dimethylformamide mix solvent. Crystal data: triclinic, space group P ī, a = 10.8620(3), b = 11.7453 (3), c = 12.4417(2) ?, α = 62.255(0), β = 79.097(2), γ = 86.764(2)°, V = 1378.52(6) ?3, Z = 2, Mr = 719.835, Dc = 1.734 g/cm3, F(000) = 714, μ(MoKα) = 3.739 mm-1, T = 293(2) K, final R = 0.0594 and wR = 0.1416 for 2943 observed reflections with I > 2.0σ(I). The structure of Cu(C13H9N3O2Br)2@H2O has been determined by X-ray analysis and revealed that two L-1 ligands coordinate to the copper(Ⅱ) ion through two oxygen and two nitrogen atoms from the hydrazine groups and two pyridine nitrogen atoms to form an elongated and distorted square-bipyramidal environment for Cu(Ⅱ). The complex is also characterized by 1H NMR spectroscopies

  18. Synthesis and Crystal Structure of a Novel Three-dimensional Cu(II) Compound {[Cu(2,2'-bipy)(C7H4O5S)(H2O)2]·(H2O}n

    Institute of Scientific and Technical Information of China (English)

    SU Wei; CAO Rong; BI Wen-Hua; LI Xing

    2005-01-01

    The title compound, {[Cu(2,2'-bipy)(C7H4O5S)(H2O)2](H2O}n (2,2'-bipy = 2,2'- bipyridine), was synthesized by the hydrothermal reaction of Cu(NO3)2(3H2O, 2,2'-bipyridine and 2-sulphobenzoic acid, and structurally characterized by single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P with a = 9.21(3), b = 10.17(3), c = 10.77(3) (A), α = 77.017(16), β = 89.80(8), γ = 68.46(7)°, V = 911(5) (A)3, Z = 2, (D/s)max = 0.001, Mr = 473.94, Dc = 1.728 g/cm3, μ(MoKα) = 1.365 mm-1, F(000) = 486, the final R = 0.0246 and wR = 0.0628 for 3809 observed reflections with I > 2σ(I). The mononuclear crystal structure extends into a two-dimensional net- work via hydrogen-bonding interactions and a three-dimensional framework is further formed by means of π-π stacking interactions.

  19. Normal vibrations and vibrational amplitudes of the water molecule in crystalline barium nitrite monohydrate, Ba(NO 2) 2 · H 2O

    Science.gov (United States)

    Eriksson, Anders; de Villepin, Jacqueline; Romain, François

    1986-01-01

    Infrared and Raman spectroscopy and normal coordinate analysis used to investigate the detailed forms of the internal vibrations and the librations of the water molecule in Ba(NO 2) 2 · H 2O. The asymmetric bonding situation is shown to result in normal vibrations that tend to give displacements more or less localized to one OH bond of the water molecule. Thus, the mixing of twisting and wagging produces two normal modes which are more like H(1) and H(2) out-of-plane displacement, respectively. The corresponding mixing of bending and rocking also occurs, but to a smaller extent. Vibrational amplitudes for the hydrogen nuclei of the water molecule are derived in two ways; from earlier diffraction studies and from the normal coordinate analysis. The agreement between the two sets of amplitude is found to be very good in the OH bond directions and in the out-of-plane direction, but somewhat poorer in the in-plane direction which is perpendicular to the OH bonds. Some systematic deviations from the equilibrium geometry of the water molecule as obtained by neutron diffraction are discussed in view of the calculated normal vibrations and the vibrational model used in the diffraction experiment.

  20. 二苯乙烯苷对H2O2诱导血管内皮细胞黏附分子表达的影响%Effect of TSG on expression of adhesion molecule induced by H2O2 on vascular endothelial cell

    Institute of Scientific and Technical Information of China (English)

    张彩平; 杨滢; 田英; 乔新惠; 龙石银; 陈志军; 田汝芳

    2012-01-01

    Aim To study the effect of 2,3,5,4' -tetra-hydroxystilbene-2-O-β-D-glucoside on expression of adhesion molecules P-selectin, E-selectin, ICAM-1, VCAM-1 and MCP-1 induced by H2O2 on human umbilical vein endothelial cells ( HUVECs). Methods HUVECs were cultured in vitro. The experiment was divided into four groups: control group, H2 O2 group, positive group, and TSG group. The expression of P-selectin, E-selectin, ICAM-1, VCAM-1 and MCP-1 mRNA and protein were respectively detected by re-verse transcriptase polymerase chain reaction ( RT-PCR ) and enzyme-linked immunosorbent assay ( ELISA). Results After endothelial cells treated with 200 μmol · L-1 H2O2 for 24 h, the expression of P-se-lectin, E-selectin, ICAM-1, VCAM-1 and MCP-1 mR-NA and protein level was significant higher. After TSG pretreatment endothelial cells for 4h before treated with 200 μmol · L-1 H2O2, results showed that TSG could inhibit the expression of P-selectin, E-selectin, ICAM-1, VCAM-1 and MCP-1 mRNA and protein level induced by H2O2 on endothelial cells. Conclusion TSG can inhibit the expression of adhesion molecules induced by H2O2 on human umbilical vein endothelial cells and accordingly slow down atherosclerosis.%目的 研究二苯乙烯苷(TSG)对过氧化氢(H2O2)诱导损伤的人脐静脉内皮细胞P-selectin、E-selectin、ICAM-1、VCAM-1和MCP-1表达的影响.方法 体外培养人脐静脉内皮细胞,实验分为空白对照组、H2O2组、辛伐他汀组、TSG组,运用逆转录聚合酶链式反应和酶联免疫吸附试验分别检测P-selectin、E-selectin、ICAM-1、VCAM-1和MCP-1 mRNA与蛋白的表达.结果 200 μmol·L-1的H2O2作用内皮细胞24 h后,P-selectin、E-selectin、ICAM-1、VCAM-1和MCP-1的mRNA和蛋白表达水平均明显上调;经TSG预处理内皮细胞4 h后,再加200 μmol·L-1的H2O2作用内皮细胞24 h,结果显示:TSG能抑制H2O2诱导的内皮细胞P-selnecti、E-selectin、ICAM-1、VCAM-1和MCP-1的 mRNA和蛋白的表达.结论 TSG可抑制H

  1. Cu(Nor)2·5H2O, a complex of Cu(II) with Norfloxacin: theoretic approach and biological studies. Cytotoxicity and genotoxicity in cell cultures.

    Science.gov (United States)

    Di Virgilio, A L; León, I E; Franca, C A; Henao, I; Tobón, G; Etcheverry, S B

    2013-04-01

    Norfloxacin is a fluoroquinolone antibiotic used in the treatment of bacterial infections. In this article, we studied the potential antitumoral action of a complex of Norfloxacin with Cu(II), Cu(Nor)(2)·5H(2)O on osteosarcoma cells (UMR106) and calvaria-derived cells (MC3T3-E1), evaluating its cytotoxicity and genitoxicity. We have also elucidated the more stable conformation of this complex under physiologic conditions by Molecular Dynamic simulations based on the model of the canonical ensemble and PM6 force field. When solvent effect was taken into account, the complex conformation with both carbonyl groups in opposite sides displayed lower energy. Cu(Nor)(2)·5H(2)O caused an inhibitory effect on the proliferation on both cell lines from 300 μM (P < 0.01). Nevertheless, the decline on cell proliferation of UMR106 cells was more pronounced (45 % vs basal) than in MC3T3-E1 cells (20 % vs basal) at 300 μM (P < 0.01). Cu(Nor)(2)·5H(2)O altered lysosomal metabolism (Neutral Red assay) in a dose-dependent manner from 300 μM (P < 0.001). Morphological studies showed important transformations that correlated with a decrease in the number of cells in a dose-dependent manner. Moreover, Cu(Nor)(2)·5H(2)O caused statistically significant genotoxic effects on both osteoblast cell lines in a lower range of concentrations (Micronucleus assay) (P < 0.05 at 10 μM, P < 0.001 from 25 to 50 μM). UMR106 cells displayed a dose-related genotoxic effect between 5 and 25 μM while the MC3T3-E1 cells showed a narrower concentration dependent range. Altogether, these results suggest that Cu(Nor)(2)·5H(2)O is a good candidate to be further evaluated for alternative therapeutics in cancer treatment.

  2. Studies on magnetic properties of unique molecular magnet {[FeII(pyrazole)4]2[NbIV(CN)8]•4H2O}n

    Science.gov (United States)

    Konieczny, P.; Pełka, R.; Zieliński, P. M.; Wasiutyński, T.; Pinkowicz, D.; Sieklucka, B.

    2013-01-01

    In this paper magnetic properties of hybrid inorganic-organic compound {[FeII(pyrazole)4]2[NbIV(CN)8]•4H2O}n are presented. This is a three dimensional molecular magnet with well localized magnetic moments, which make it a suitable candidate for testing magnetic models. In order to characterize the magnetic properties of the above compound we performed the AC/DC magnetometry in the range 0-5 T. The special attention was paid to the phase transition at 7.9 K. The study in magnetic field supports magnetic ordering below 7.9 K.

  3. H2O2-reactivity of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine ligands with 6-phenyl substituents.

    Science.gov (United States)

    Kunishita, Atsushi; Kubo, Minoru; Ishimaru, Hirohito; Ogura, Takashi; Sugimoto, Hideki; Itoh, Shinobu

    2008-12-15

    The structure and H(2)O(2)-reactivity of a series of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine (TPA) derivatives having a phenyl group at the 6-position of pyridine donor group(s) [(6-phenylpyridin-2-yl)methyl]bis[(pyridin-2-yl)methyl]amine (Ph(1)TPA), bis[(6-phenylpyridin-2-yl)methyl][(pyridin-2-yl)methyl]amine (Ph(2)TPA), and tris[(6-phenylpyridin-2-yl)methyl]amine (Ph(3)TPA) have systematically been examined to get insights into the aromatic substituent (6-Ph) effects on the coordination chemistry of TPA ligand system. The X-ray crystallographic analyses have revealed that [Cu(II)(TPA)(CH(3)CN)](ClO(4))(2) (CuTPA) and [Cu(II)(Ph(3)TPA)(CH(3)CN)](ClO(4))(2) (3) exhibit a trigonal bipyramidal structure, whereas [Cu(II)(Ph(1)TPA)(CH(3)CN)](ClO(4))(2) (1) shows a slightly distorted square pyramidal structure and [Cu(II)(Ph(2)TPA)(CH(3)CN)](ClO(4))(2) (2) has an intermediate structure between trigonal bipyramidal and square pyramidal. On the other hand, the UV-vis and ESR data have suggested that all the copper(II) complexes have a similar trigonal bipyramidal structure in solution. The redox potentials of CuTPA, 1, 2, and 3 have been determined as E(1/2) = -0.34, -0.28, -0.16, and -0.04 mV vs Ag/AgNO(3), respectively, demonstrating that introduction of each 6-Ph group causes positive shift of E(1/2) about 0.1 V. Notable difference in H(2)O(2)-reactivity has been found among the copper(II) complexes. Namely, CuTPA and 1 afforded mononuclear copper(II)-hydroperoxo complexes CuTPA-OOH and 1-OOH, respectively, whereas complex 2 provided bis(mu-oxo)dicopper(III) complex 2-oxo. On the other hand, copper(II) complex 3 was reduced to the corresponding copper(I) complex 3(red). On the basis of the H(2)O(2)-reactivity together with the X-ray structures and the redox potentials of the copper(II) complexes, the substituent effects of 6-Ph are discussed in detail.

  4. Decomplexation efficiency and mechanism of Cu(II)-EDTA by H2O2 coupled internal micro-electrolysis process.

    Science.gov (United States)

    Zhou, Dongfang; Hu, Yongyou; Guo, Qian; Yuan, Weiguang; Deng, Jiefan; Dang, Yapan

    2016-12-29

    Internal micro-electrolysis (IE) coupled with Fenton oxidation (IEF) was a very effective technology for copper (Cu)-ethylenediaminetetraacetic acid (EDTA) wastewater treatment. However, the mechanisms of Cu(2+) removal and EDTA degradation were scarce and lack persuasion in the IEF process. In this paper, the decomplexation and removal efficiency of Cu-EDTA and the corresponding mechanisms during the IEF process were investigated by batch test. An empirical equation and the oxidation reduction potential (ORP) index were proposed to flexibly control IE and the Fenton process, respectively. The results showed that Cu(2+), total organic carbon (TOC), and EDTA removal efficiencies were 99.6, 80.3, and 83.4%, respectively, under the proper operation conditions of iron dosage of 30 g/L, Fe/C of 3/1, initial pH of 3.0, Fe(2+)/H2O2 molar ratio of 1/4, and reaction time of 20 min, respectively for IE and the Fenton process. The contributions of IE and Fenton to Cu(2+) removal were 91.2 and 8.4%, respectively, and those to TOC and EDTA removal were 23.3, 25.1, and 57, 58.3%, respectively. It was found that Fe(2+)-based replacement-precipitation and hydroxyl radical (•OH) were the most important effects during the IEF process. •OH played an important role in the degradation of EDTA, whose yield and productive rate were 3.13 mg/L and 0.157 mg/(L min(-1)), respectively. Based on the intermediates detected by GC-MS, including acetic acid, propionic acid, pentanoic acid, amino acetic acid, 3-(diethylamino)-1,2-propanediol, and nitrilotriacetic acid (NTA), a possible degradation pathway of Cu-EDTA in the IEF process was proposed. Graphical abstract The mechanism diagram of IEF process.

  5. Observation of a HI leaving group following ultraviolet photolysis of CH 2I 2 in water and an ab initio investigation of the O-H insertion/HI elimination reactions of the CH 2I-I isopolyhalomethane species with H 2O and 2H 2O

    OpenAIRE

    Li, YL; Zhao, C.; Kwok, WM; Guan, X; Zuo, P; Phillips, DL

    2003-01-01

    Ultraviolet/visible absorption and pH measurements that indicate significant production of H + and I - product following ultraviolet photolysis of CH 2I 2 in liquid water are presented. As such, the chemical reactivity of isodiiodomethane (CH 2I-I) with H 2O and 2H 2O is explored using ab initio calculations and compared to previous results. The CH 2I-I isopolyhalomethane species is found to react with water by an O-H insertion/HI elimination reaction mechanism that forms a HI leaving group.

  6. Experimental measurements of water molecule binding energies for the second and third solvation shells of [Ca(H2O)n]2+ complexes

    Science.gov (United States)

    Bruzzi, E.; Stace, A. J.

    2017-01-01

    Further understanding of the biological role of the Ca2+ ion in an aqueous environment requires quantitative measurements of both the short- and long-range interactions experienced by the ion in an aqueous medium. Here, we present experimental measurements of binding energies for water molecules occupying the second and, quite possibly, the third solvation shell surrounding a central Ca2+ ion in [Ca(H2O)n]2+ complexes. Results for these large, previously inaccessible, complexes have come from the application of finite heat bath theory to kinetic energy measurements following unimolecular decay. Even at n = 20, the results show water molecules to be more strongly bound to Ca2+ than would be expected just from the presence of an extended network of hydrogen bonds. For n > 10, there is very good agreement between the experimental binding energies and recently published density functional theory calculations. Comparisons are made with similar data recorded for [Ca(NH3)n]2+ and [Ca(CH3OH)n]2+ complexes.

  7. Effects of Self-coiling of Organic Molecules on Intramolecular Exciplex Formation and Fluorescence Quenching in DX-H2O Solvent System

    Institute of Scientific and Technical Information of China (English)

    CHEN,Ying-Qi(陈英奇); WANG,Xiao-Zhong(王晓钟); JIANG,Xi-Kui(蒋锡夔); SHI,Ji-Liang(史济良); SHI,Min(施敏); LI,Zhan-Tmg(黎占亭)

    2002-01-01

    Effects of self-coiling of organic molecules on intramolecular exciplex formation of compound I, in which the carbazole chromophore and terephthalic acid methylester acceptor group are linked by one (CH2)10 chain, and the decrease of the fluorescence intensities of compounds H, Ⅲ, and Ⅳ, in which the carbazole chromophore and 3,5-dinitrobenzoate are connected by one aliphatic chain of (CH2)10 (Ⅱ), (CH2)12 (Ⅲ),or (CH2)4 (Ⅳ), have been studied in the dioxane(DX)-H2Obinary system. The results show that self-coiling of organic molecules in DX-H2O facilitates intramolecular exciplex formation of Ⅰ and induces the decrease of fluorescence intensities of Ⅱ, because of the proximity effect brought about by selfcoiling of organic molecules under hydrophobic-lipophilic interaction (HLI) between the excited carbazole chromophore and the acceptor. Since the similar effects are observed even when the concentrations of the probes are less than their CAgCs (critical aggregate concentratons) in the DX-H2Omixture withthe same φ values, formation of the intermolecular exciplex has been excluded. The effects are found to be strongly depended on φ values, indicating that they are mainly driven by HLI. The properties of the acceptors can also affect the intrmolecular exciplex formation. With terephthalic acid methylester moiety as the acceptor, the carbazole chromophore exihibits the fluorescence spectra of the exciplex,while with 3,5- dinitrobenzoate moiety as the acceptor, only the fluorescence spectra of excited carbazolyl chromphore are observed.

  8. Purification and characterization of a surfactin-like molecule produced by Bacillus sp. H2O-1 and its antagonistic effect against sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    Korenblum Elisa

    2012-11-01

    Full Text Available Abstract Background Bacillus sp. H2O-1, isolated from the connate water of a Brazilian reservoir, produces an antimicrobial substance (denoted as AMS H2O-1 that is active against sulfate reducing bacteria, which are the major bacterial group responsible for biogenic souring and biocorrosion in petroleum reservoirs. Thus, the use of AMS H2O-1 for sulfate reducing bacteria control in the petroleum industry is a promising alternative to chemical biocides. However, prior to the large-scale production of AMS H2O-1 for industrial applications, its chemical structure must be elucidated. This study also analyzed the changes in the wetting properties of different surfaces conditioned with AMS H2O-1 and demonstrated the effect of AMS H2O-1 on sulfate reducing bacteria cells. Results A lipopeptide mixture from AMS H2O-1 was partially purified on a silica gel column and identified via mass spectrometry (ESI-MS. It comprises four major components that range in size from 1007 to 1049 Da. The lipid moiety contains linear and branched β-hydroxy fatty acids that range in length from C13 to C16. The peptide moiety contains seven amino acids identified as Glu-Leu-Leu-Val-Asp-Leu-Leu. Transmission electron microscopy revealed cell membrane alteration of sulfate reducing bacteria after AMS H2O-1 treatment at the minimum inhibitory concentration (5 μg/ml. Cytoplasmic electron dense inclusions were observed in treated cells but not in untreated cells. AMS H2O-1 enhanced the osmosis of sulfate reducing bacteria cells and caused the leakage of the intracellular contents. In addition, contact angle measurements indicated that different surfaces conditioned by AMS H2O-1 were less hydrophobic and more electron-donor than untreated surfaces. Conclusion AMS H2O-1 is a mixture of four surfactin-like homologues, and its biocidal activity and surfactant properties suggest that this compound may be a good candidate for sulfate reducing bacteria control. Thus, it is a potential

  9. Synthesis and characterization of dinuclear complexes containing the Fe(III)-F...(H2O)M(II) motif

    DEFF Research Database (Denmark)

    Ghiladi, M; Jensen, K.B.; Jiang, Jianzhong;

    1999-01-01

    The dinucleating phenolate-hinged ligand 4-tert-butyl-2,6-bis[bis(2-pyridylmethyl)aminomethyl]phenolate(bpb p) has been used to prepare a series of Fe(III)M(II) complexes containing independent species at the exogenous binding sites. These sites are occupied by fluoride and water ligands and show...

  10. Reactions of H2O3 in the pulse-irradiated Fe(II)-O2 system

    DEFF Research Database (Denmark)

    Sehested, Knud; Bjergbakke, Erling; Lang Rasmussen, O.;

    1969-01-01

    G(Fe(III)] is measured in pulse-irradiated O2-saturated solutions of 20 to 160 μMFe(II), at the p H's 0.46, 1.51, and 2.74 H2SO4 and HClO4 and with dose rates between 1 and 8 krad/1 μsec pulse. Based on homogeneous kinetics, the results are interpreted by a system of 18 reactions. The formation...

  11. Electron spin relaxation in pseudo-Jahn-Teller low-symmetry Cu(II) complexes in diaqua(L-aspartate)Zn(II).H(2)O crystals.

    Science.gov (United States)

    Hoffmann, S K; Hilczer, W; Goslar, J; Massa, M M; Calvo, R

    2001-11-01

    Low-temperature (4-55 K) pulsed EPR measurements were performed with the magnetic field directed along the z-axis of the g-factor of the low-symmetry octahedral complex [(63)Cu(L-aspartate)(2)(H2O)2] undergoing dynamic Jahn-Teller effect in diaqua(L-aspartate)Zn(II) hydrate single crystals. Spin-lattice relaxation time T(1) and phase memory time T(M) were determined by the electron spin echo (ESE) method. The relaxation rate 1/T(1) increases strongly over 5 decades in the temperature range 4-55 K. Various processes and mechanisms of T(1)-relaxation are discussed, and it is shown that the relaxation is governed mainly by Raman relaxation processes with the Debye temperature Theta(D)=204 K, with a detectable contribution from disorder in the doped Cu(2+) ions system below 12 K. An analytical approximation of the transport integral I(8) is given in temperature range T=0.025-10Theta(D) and applied for computer fitting procedures. Since the Jahn-Teller distorted configurations differ strongly in energy (delta(12)=240 cm(-1)), there is no influence of the classical vibronic dynamics mechanism on T(1). Dephasing of the ESE (phase relaxation) is governed by instantaneous diffusion and spectral diffusion below 20 K with resulting rigid lattice value 1/T(0)(M)=1.88 MHz. Above this temperature the relaxation rate 1/T(M) increases upon heating due to two mechanisms. The first is the phonon-controlled excitation to the first excited vibronic level of energy Delta=243 cm(-1), with subsequent tunneling to the neighbor potential well. This vibronic-type dynamics also produces a temperature-dependent broadening of lines in the ESEEM spectra. The second mechanism is produced by the spin-lattice relaxation. The increase in T(M) is described in terms of the spin packets forming inhomogeneously broadened EPR lines.

  12. Grain-size-induced weakening of H2O ices I and II and associated anisotropic recrystallization

    Science.gov (United States)

    Stern, L.A.; Durham, W.B.; Kirby, S.H.

    1997-01-01

    Grain-size-dependent flow mechanisms tend to be favored over dislocation creep at low differential stresses and can potentially influence the rheology of low-stress, low-strain rate environments such as those of planetary interiors. We experimentally investigated the effect of reduced grain size on the solid-state flow of water ice I, a principal component of the asthenospheres of many icy moons of the outer solar system, using techniques new to studies of this deformation regime. We fabricated fully dense ice samples of approximate grain size 2 ?? 1 ??m by transforming "standard" ice I samples of 250 ?? 50 ??m grain size to the higher-pressure phase ice II, deforming them in the ice II field, and then rapidly releasing the pressure deep into the ice I stability field. At T ??? 200 K, slow growth and rapid nucleation of ice I combine to produce a fine grain size. Constant-strain rate deformation tests conducted on these samples show that deformation rates are less stress sensitive than for standard ice and that the fine-grained material is markedly weaker than standard ice, particularly during the transient approach to steady state deformation. Scanning electron microscope examination of the deformed fine-grained ice samples revealed an unusual microstructure dominated by platelike grains that grew normal to the compression direction, with c axes preferentially oriented parallel to compression. In samples tested at T ??? 220 K the elongation of the grains is so pronounced that the samples appear finely banded, with aspect ratios of grains approaching 50:1. The anisotropic growth of these crystallographically oriented neoblasts likely contributes to progressive work hardening observed during the transient stage of deformation. We have also documented remarkably similar microstructural development and weak mechanical behavior in fine-grained ice samples partially transformed and deformed in the ice II field.

  13. Crystalline and Molecular Structure of Hexaaqua-1,3-diammoniumpropane Cobalt(II Nitrate, Co(H2O 6 [C3H12N2] (NO34

    Directory of Open Access Journals (Sweden)

    M. L. Mrad

    2010-01-01

    Full Text Available Chemical preparation and x-ray characterization of a new compound hexaaqua-1,3-diammoniumpropane cobalt(II nitrate, Co(H2O 6 [C3H12N2] (NO34 are reported. This mixed organo-mineral compound crystallizes in the orthorhombic system with Cmcm space group. The unit cell dimensions are: a = 10.795(7, b = 11.969(4, c = 14.685(5 Å, Z = 4 and V = 1897.5(12 Å3. The structure was solved using the direct method and refined to reliability R-factor of 0.036 using 2554 independent reflections. In this atomic arrangement the different species built a three-dimensional network.

  14. An unusual (H(2)O)(20) discrete water cluster in the supramolecular host of a charge transfer platinum(ii) complex: cytotoxicity and DNA cleavage activities.

    Science.gov (United States)

    Mandal, Sutanuva; Castiñeiras, Alfonso; Mondal, Tapan K; Mondal, Arindam; Chattopadhyay, Dhrubajyoti; Goswami, Sreebrata

    2010-10-28

    The chemical reaction of Pt(II)(L(1))Cl(2) [L(1) = N-4-tolylpyridine-2-aldimine] with a bidentate N,S-donor atom ligand, 2-methylthioaniline, (HL(2)) in alkaline methanolic medium yielded a mixed ligand donor-acceptor complex, [Pt(II)(L(1))(L(2))]Cl, [1]Cl. The complex has been characterized by different spectroscopic and electrochemical techniques. The complex showed intense interligand charge transfer (ILCT) transition in the long wavelength region of UV-vis spectrum (>600 nm). The single-crystal X-ray structure of complex, [1]Cl·3.3H(2)O is reported. The cationic complex upon crystallization from aqueous methanol solvent produces an assembly of discrete, three dimensional (H(2)O)(20) guest moiety within the reference Pt-complex host lattice. The water assembly showed a unique type of aggregation of a distorted cube encapsulated by hydrogen bonded network of a twelve-water ring. The complex displayed one reversible cathodic response at -0.75 V and two irreversible anodic responses at 0.42 and 0.79 V versus Ag/AgCl reference electrode. The redox processes are characterized by EPR and spectroelectrochemistry. Density-functional theory calculations were employed to confirm the structural features and to support the spectral and redox properties of the complex. The square-planar complex has been found to intercalate DNA. Fluorescence spectroscopy, circular dichroism, cyclic voltammetry, viscosity measurements, together with DNA melting studies have been employed to characterize the binding of [1]Cl with calf thymus DNA. Agarose gel electrophoresis indicates that the complex cleaves supercoiled (SC) pUC19 plasmid DNA to its nicked circular (NC) form via singlet oxygen. As determined by a MTT assay, [1]Cl exhibits significant cytotoxicity with IC(50) value 58 μM.

  15. Antioxidant/prooxidant effects of α-tocopherol, quercetin and isorhamnetin on linoleic acid peroxidation induced by Cu(II) and H2O2.

    Science.gov (United States)

    Bakır, Temelkan; Sönmezoğlu, Inci; Imer, Filiz; Apak, Reşat

    2014-03-01

    The peroxidation of linoleic acid (LA) in the presence of copper(II) (Cu(II)) ions alone and with α-tocopherol (α-TocH) was investigated in aerated and incubated emulsions at 37 °C and pH 7. Additionally, the effects of quercetin (QR) and its O-methylated derivative, isorhamnetin (IR), as potential antioxidant protectors were studied in the (Cu(II) + TocH)-induced LA peroxidation system. Cu(II)-induced LA peroxidation followed pseudo-first-order kinetics with respect to primary (hydroperoxides) and secondary (aldehydes- and ketones-like) oxidation products, which were determined by ferric thiocyanate and thiobarbituric acid-reactive substances methods, respectively. As opposed to the concentration-dependent (at 0.6 and 10.0 µM) prooxidative action of α-TocH in the absence of QR and IR, the latter two compounds showed antioxidant effect over TocH. The peroxidation of LA in the presence of Cu(II)-H(2)O(2) combination alone and with TocH, QR and IR were also investigated in aerated and incubated emulsions, where the latter three compounds exhibited antioxidant effects.

  16. Ternary complexes metal [Co(II), Ni(II), Cu(II) and Zn(II)]--ortho-iodohippurate (I-hip)--acyclovir. X-ray characterization of isostructural [(Co, Ni or Zn)(I-hip)(2)(ACV)(H(2)O)(3)] with stacking as a recognition factor.

    Science.gov (United States)

    Barceló-Oliver, M; Terrón, A; García-Raso, A; Fiol, J J; Molins, E; Miravitlles, C

    2004-11-01

    Four ternary metal--ortho-iodohippurate (I-hip)--acyclovir (ACV) complexes, [M(I-hip)(2)(ACV)(H(2)O)(3)] where M is Co(II) (1), Ni(II) (2), Cu (3) and Zn(II) have been obtained by reaction between the corresponding binary complexes M(II)(I-hip)(2)xnH(2)O and ACV. Three ternary complexes (M=Co, Ni and Zn) and the corresponding Zn(II)--ortho-iodohippurate binary derivative have been structurally characterized by X-ray diffraction: The studies show these three ternary complexes are isostructural and present, in solid state, an interesting stacking between the nucleobase and the aryl ring of the hippurate moiety, which probably promotes the formation of ternary complexes. Moreover, the two different ligands interact between them by means of ancillary hydrogen bonds with water molecules coordinated to the metal ion. It must be mentioned that these two recognition factors, hydrogen bonds plus stacking, could explain the reason for the isostructurality of these ternary derivatives with so different three metal ions, with diverses trends in coordination numbers and geometries. In solid state, there are two enantiomeric molecules that are related by an inversion center as the crystal-building unit (as a translational motif) for the ternary complexes.

  17. Thermodynamic Modeling of Poorly Complexing Metals in Concentrated Electrolyte Solutions: An X-Ray Absorption and UV-Vis Spectroscopic Study of Ni(II) in the NiCl2-MgCl2-H2O System

    Science.gov (United States)

    Zhang, Ning; Brugger, Joël; Etschmann, Barbara; Ngothai, Yung; Zeng, Dewen

    2015-01-01

    Knowledge of the structure and speciation of aqueous Ni(II)-chloride complexes is important for understanding Ni behavior in hydrometallurgical extraction. The effect of concentration on the first-shell structure of Ni(II) in aqueous NiCl2 and NiCl2-MgCl2 solutions was investigated by Ni K edge X-ray absorption (XAS) and UV-Vis spectroscopy at ambient conditions. Both techniques show that no large structural change (e.g., transition from octahedral to tetrahedral-like configuration) occurs. Both methods confirm that the Ni(II) aqua ion (with six coordinated water molecules at RNi-O = 2.07(2) Å) is the dominant species over the whole NiCl2 concentration range. However, XANES, EXAFS and UV-Vis data show subtle changes at high salinity (> 2 mol∙kg-1 NiCl2), which are consistent with the formation of small amounts of the NiCl+ complex (up to 0.44(23) Cl at a Ni-Cl distance of 2.35(2) Å in 5.05 mol∙kg-1 NiCl2) in the pure NiCl2 solutions. At high Cl:Ni ratio in the NiCl2-MgCl2-H2O solutions, small amounts of [NiCl2]0 are also present. We developed a speciation-based mixed-solvent electrolyte (MSE) model to describe activity-composition relationships in NiCl2-MgCl2-H2O solutions, and at the same time predict Ni(II) speciation that is consistent with our XAS and UV-Vis data and with existing literature data up to the solubility limit, resolving a long-standing uncertainty about the role of chloride complexing in this system. PMID:25885410

  18. New topology in azide-bridged cobalt(II) complexes: the weak ferromagnet [Co(2)(N(3))(4)(Hexamethylenetetramine)(H(2)O)](n).

    Science.gov (United States)

    Mautner, Franz A; Ohrström, Lars; Sodin, Beate; Vicente, Ramon

    2009-07-06

    A new polynuclear azido-bridged Co(II) compound with formula [Co(2)(N(3))(4)(HMTA)(H(2)O)](n) (1) (HMTA = hexamethylenetetramine) has been structurally and magnetically characterized. The compound 1 crystallizes in the monoclinic system C2/m space group, and consist of a complex three-dimensional system in which end-to-end and end-on azido bridging ligands between the Co(II) atoms coexist. The HMTA ligand is also linking three different Co(II) atoms. The network analysis shows for 1 a three- and six-connected network topology not previously reported. The magnetic properties of 1 are also reported, and it was found that the magnetic interactions define another new three- and four-connected net assigned as a (6.8(2))(6(4).10(2))-tfo net. In the high temperature region the chi(M) versus T plot can be fitted by using the Curie-Weiss law, and the best fit theta value is -26.6 K. For 1 magnetic ordering and spontaneous magnetization is achieved below T(c) = 15.6 K.

  19. Preparation, configurational and DFT-NBO analysis of nickel(II) complexes with edta-type ligands containing six-membered backbone ring : crystal structure of [Ni(H2O)(6)][Ni(1,3-pdta)]center dot 2H(2)O

    NARCIS (Netherlands)

    Belosevic, Svetlana; Vasojevic, Miorad M.; Jeremic, Marija S.; Meetsma, Auke; Matovic, Zoran D.

    2013-01-01

    New hexadentate nickel(II) complex Mg[Ni(1,3-pd3ap)]center dot 10H(2)O containing unsymmetrical edta-type ligand, 1,3-propanediamine-N,N,N '-triacetate-N-3-propionate (1,3-pd3ap), has been prepared, chromatographically separated, and characterized. Only one [trans(O-5)] of the two possible geometric

  20. Candidate Water Vapor Lines to Locate the H2O Snowline through High-dispersion Spectroscopic Observations. II. The Case of a Herbig Ae Star

    Science.gov (United States)

    Notsu, Shota; Nomura, Hideko; Ishimoto, Daiki; Walsh, Catherine; Honda, Mitsuhiko; Hirota, Tomoya; Millar, T. J.

    2017-02-01

    Observationally measuring the location of the {{{H}}}2{{O}} snowline is crucial for understanding planetesimal and planet formation processes, and the origin of water on Earth. In disks around Herbig Ae stars (T * ∼ 10,000 K, M * ≳ 2.5M ⊙), the position of the {{{H}}}2{{O}} snowline is farther from the central star compared with that around cooler and less massive T Tauri stars. Thus, the {{{H}}}2{{O}} emission line fluxes from the region within the {{{H}}}2{{O}} snowline are expected to be stronger. In this paper, we calculate the chemical composition of a Herbig Ae disk using chemical kinetics. Next, we calculate the {{{H}}}2{{O}} emission line profiles and investigate the properties of candidate water lines across a wide range of wavelengths (from mid-infrared to submillimeter) that can locate the position of the {{{H}}}2{{O}} snowline. Those lines identified have small Einstein A coefficients (∼ {10}-6{--}{10}-3 s‑1) and relatively high upper-state energies (∼1000 K). The total fluxes tend to increase with decreasing wavelengths. We investigate the possibility of future observations (e.g., ALMA, SPICA/SMI-HRS) locating the position of the {{{H}}}2{{O}} snowline. Since the fluxes of those identified lines from Herbig Ae disks are stronger than those from T Tauri disks, the possibility of a successful detection is expected to increase for a Herbig Ae disk.

  1. Catalytic Performance of a New 1D Cu(II Coordination Polymer {Cu(NO3(H2O}(HTae(4,4′-Bpy for Knoevenagel Condensation

    Directory of Open Access Journals (Sweden)

    Edurne S. Larrea

    2016-12-01

    Full Text Available The {Cu(NO3(H2O}(HTae(4,4′-Bpy (H2Tae = 1,1,2,2-tetraacetylethane, 4,4′-Bpy = 4,4′-Dipyridyl 1D coordination polymer has been obtained by slow evaporation. The crystal structure consists of parallel and oblique {Cu(HTae(4,4′-Bpy} zig-zag metal–organic chains stacked along the [100] crystallographic direction. Copper(II ions are in octahedral coordination environment linked to two nitrogen atoms of two bridging 4,4′-Bpy and to two oxygen atoms of one HTae molecule in the equatorial plane. The occupation of the axial positions varies from one copper atom to another, with different combinations of water molecules and nitrate anions, giving rise to a commensurate super-structure. By means of the thermal removal of water molecules, copper coordinatively unsaturated centres are obtained. These open metal sites could act as Lewis acid active sites in several heterogeneous catalytic reactions. The dehydrated compound, CuHTaeBpy_HT, has been tested as a heterogeneous recoverable catalyst for Knoevenagel condensation reactions. The catalyst is active and heterogeneous for the condensation of aldehydes with malononitrile at 60 °C using a molar ratio catalyst:substrate of 3 % and toluene as solvent. The catalyst suffers a partial loss of activity when reusing it, but can be reused at least four times.

  2. Apoptosis-inducing Effect of a Palladium(II) Complex-[PdCl(terpy)](sac).2H2O] on Ehrlich Ascites Carcinoma (EAC) in Mice.

    Science.gov (United States)

    Ikitimur-Armutak, Elif I; Ulukaya, Engin; Gurel-Gurevin, Ebru; Yaylim, Ilhan; Isbilen-Basok, Banu; Sennazli, Gulbin; Yuzbasioglu-Ozturk, Gulay; Sonmez, Kivilcim; Celik, Faruk; Kucukhuseyin, Ozlem; Korkmaz, Gurbet; Yilmaz, Veysel T; Zeybek, Sakir Umit

    2016-01-01

    New compounds for cancer treatment are needed due to persistenly unsatisfactory management of cancer. [PdCl(terpy)](sac)·2H2O] (sac=saccharinate, and terpy=2,2':6',2"-terpyridine) is a compound synthesized for this purpose. We investigated its anti-proliferative and pro-apoptotic effects on Ehrlich Ascites Carcinoma (EAC) in vivo. 42 Balb-c female mice were subcutaneously (s.c.) injected with EAC cells (1st day) and then randomly divided into 5 groups: control (0.9% NaCl), complex (2 mg/kg), complex (3 mg/kg) cisplatin (4 mg/kg) and paclitaxel (12.5 mg/kg). On the 5th and 12th day animals were drug administrated. At 14th day, animals were sacrificed. Expression of cell death and/or cell cycle-related markers (Bcl-2, Bax, active caspase-3, p53, PCNA) and apoptosis were investigated immunohisto-chemically. Survival-related markers (Akt, GSK-3β, IGF-1R, IR, IRS-1, p70S6K, PRAS40) were evaluated by luminex analysis. Expression of p53, PCNA, Bcl-2 was found decreased (p<0.001) and that of active caspase-3, Bax, and apoptotic cells was found increased (p<0.001) in all groups. The survival-related markers did not show any statistical difference in complex groups. The Pd(II)-complex seems to have a strong anticancer activity on EAC by inducing apoptosis via both suppression of proliferation and activation of apoptosis in vivo, similar to the effects of cisplatin and paclitaxel. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  3. Channel-selective independent sorption and collection of hydrophilic and hydrophobic molecules by Cs2[Cr3O(OOCC2H5)6(H2O)3]2[alpha-SiW12O40] ionic crystal.

    Science.gov (United States)

    Jiang, Chunjie; Lesbani, Aldes; Kawamoto, Ryosuke; Uchida, Sayaka; Mizuno, Noritaka

    2006-11-08

    An ionic crystal of Cs2[Cr3O(OOCC2H5)6(H2O)3]2[alpha-SiW12O40].4H2O 1a with hydrophilic and hydrophobic channels has been designed and successfully synthesized. The guest-free phase 1b sorbs dichloromethane and water in the hydrophobic and hydrophilic channels, respectively. The rate and equilibrium amount of the dichloromethane sorption into the hydrophobic channel and those of water into the hydrophilic channel were independent of each other. The sorption properties can be applied to the channel-selective sorption and collection of hydrophobic (dichloromethane) and hydrophilic (water) molecules from the mixture.

  4. Reversible adsorption of a planar cyclic (H2O)6 cluster held in a 2D CuII-coordination framework

    Science.gov (United States)

    Zhao, Yang; Lu, Hui; Yang, Le; Luo, Geng-Geng

    2015-05-01

    Coordination polymeric solid, {[Cu(btec)0.5(bpe)(H2O)2]ṡ(H2O)4}n (1) (H4btec = 1,2,4,5-benzenetetracarboxylic acid, and bpe = 1,2-bis(4-pyridyl)ethane), has been obtained by the solution phase ultrasonic synthesis techniques. The structure established through X-ray structural analysis shows that a centrosymmetric water hexamer with planar conformation structurally similar to aromatic benzene is unambiguously crystallized within the hydrophilic channel of 1. Water escapes at 150 °C but is re-absorbed using water vapor. The reversible formation of this water cluster was supported from powder X-ray diffraction (PXRD), FTIR spectra and TGA/DTA. The reversible dehydration/rehydration behaviors enable analysis of the nature of the intermolecular interactions that occur between the planar hexameric water and the resulting host framework. When the auxiliary ligand bpe was removed from the synthetic conditions, another complex {[Cu(btec)0.5(H2O)3]ṡH2O}n (2) only encapsulating a water dimer was afforded, which suggests bpe plays an important role in the formation of the framework and water clusters.

  5. A family of new glutarate compounds: synthesis, crystal structures of: Co(H2O)5L(1), Na2[CoL2] (2), Na2[L(H2L)4/2] (3), {[Co3(H2O)6L2](HL)2}.4H2O (4), {[Co3(H2O)6L2](HL)2}.10H2O (5), {[Co3(H2O)6L2]L2/2}.4H2O (6), and Na2{[Co3(H2O)2]L8/2].6H2O (7), and magnetic properties of 1 and 2 with H2L = HOOC-(CH2)3-COOH.

    Science.gov (United States)

    Zheng, Yue-Qing; Lin, Jian-Li; Xu, Wei; Xie, Hong-Zhen; Sun, Jie; Wang, Xian-Wen

    2008-11-17

    Seven new glutaric acid complexes, Co(H 2O) 5L 1, Na 2[CoL 2] 2, Na 2[L(H 2L) 4/2] 3, {[Co 3(H 2O) 6L 2](HL) 2}.4H 2O 4, {[Co 3(H 2O) 6L 2](HL) 2}.10H 2O 5, {[Co 3(H 2O) 6L 2]L 2/2}.4H 2O 6, and Na 2{[Co 3(H 2O) 2]L 8/2].6H 2O 7 were obtained and characterized by single-crystal X-ray diffraction methods along with elemental analyses, IR spectroscopic and magnetic measurements (for 1 and 2). The [Co(H 2O) 5L] complex molecules in 1 are assembled into a three-dimensional supramolecular architecture based on intermolecular hydrogen bonds. Compound 2 consists of the Na (+) cations and the necklace-like glutarato doubly bridged [ C o L 4 / 2 ] 2 - infinity 1 anionic chains, and 3 is composed of the Na (+) cations and the anionic hydrogen bonded ladder-like [ L ( H 2 L ) 4 / 2 ] 2 - infinity 1 anionic chains. The trinuclear {[Co 3(H 2O) 6L 2](HL) 2} complex molecules with edge-shared linear trioctahedral [Co 3(H 2O) 6L 2] (2+) cluster cores in 4 and 5 are hydrogen bonded into two-dimensional (2D) networks. The edge-shared linear trioctahedral [Co 3(H 2O) 6L 2] (2+) cluster cores in 6 are bridged by glutarato ligands to generate one-dimensional (1D) chains, which are then assembled via interchain hydrogen bonds into 2D supramolecular networks. The corner-shared linear [Co 3O 16] trioctahedra in 7 are quaternate bridged by glutarato ligands to form 1D band-like anionic {[Co 3(H 2O) 2]L 8/2} (2+) chains, which are assembled via interchain hydrogen bonds into 2D layers, and between them are sandwiched the Na (+) cations. The magnetic behaviors of 1 and 2 obey the Curie-Weiss law with chi m = C/( T - Theta) with the Curie constant C = 3.012(8) cm (3) x mol (-1) x K and the Weiss constant Theta = -9.4(7) K for 1, as well as C = 2.40(1) cm (3) x mol (-1) x K and Theta = -2.10(5) K for 2, indicating weak antiferromagnetic interactions between the Co(II) ions.

  6. Syntheses, structure and magnetic properties of pillared layered diphosphonates: M2(O 3PC 6H 4PO 3)(H 2O) 2 ( M=Co II, Ni II)

    Science.gov (United States)

    Cao, Deng-Ke; Gao, Song; Zheng, Li-Min

    2004-07-01

    This paper describes the hydrothermal syntheses of two isostructural metal bisphosphonates: M2(O 3PC 6H 4PO 3)(H 2O) 2 [ M=Co II ( 1), Ni II ( 2)]. Single-crystal structure determination of compound 1 revealed a pillared layered structure in which the phenyl groups connect the inorganic layers of cobalt phosphonate. Crystal data for 1: orthorhombic, space group Pnnm, a=19.306(5), b=4.8293(12), c=5.6390(14) Å, V=525.7(2) Å 3, Z=2. Magnetic susceptibility data indicate that antiferromagnetic interactions are mediated in both cases.

  7. CO 2 and H 2O gas exchange of a triticale field: II. Micrometeorological flux studies and comparison with upscaling from porometry

    Science.gov (United States)

    Ammann, C.; Meixner, F. X.; Busch, J.; Lösch, R.

    1996-05-01

    During June and July 1995 a field experiment was conducted at a 9 ha field of cereal crop (triticale) located in Bellheim, Germany. Our investigation focused on the exchange processes of H 2O and CO 2 and micrometeorological quantities within and above the triticale canopy. Data were collected by porometer measurements at leaf scale, and canopy scale flux measurements using eddy correlation techniques. Due to the senescent state of triticale, the CO 2 exchange was generally small. The micrometeorological flux data are compared to estimates which were upscaled from porometer measurements. The results of one particular day are selected for presentation. The good agreement for both the CO 2 and H 2O fluxes, indicates that a relatively simple and direct upscaling procedure from single leaf porometry data may correctly describe the net exchange of an entire canopy.

  8. Bibliographic review and new measurements of the integrated cross sections of 8 molecules (H2O, CO, CO2, CH3OH, NH3, CH4, HCOOH and H2CO) in the solid form at 25K

    Science.gov (United States)

    Michaelle, B.; Nicolas, F.; Yves, B.; Hervé, C.; Antoine, J.; Claire, G. Marie

    2014-04-01

    Infrared spectra from ISO and Spitzer telescopes revealed the presence of several molecules in the solid phase such as H2O, CO, CO2, CH3OH, NH3, CH4, HCOOH and H2CO in the environment of some Young Stellar Objects (YSOs) ([1], [2], [3], [4]. To quantify the column density of those molecules, the knowledge of some spectroscopic parameters, especially the integrated cross section A (cm.molecule-1) is required. For some molecules, inconsistencies on the values of spectroscopic parameters can be found in the literature. The purpose of this study is to compare all the values found in the literature with the ones that we have measured recently in order to propose more convincing values.

  9. Effects of paramagnetic ferrocenium cations on the magnetic properties of the anionic single-molecule magnet [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)]-.

    Science.gov (United States)

    Kuroda-Sowa, T; Lam, M; Rheingold, A L; Frommen, C; Reiff, W M; Nakano, M; Yoo, J; Maniero, A L; Brunel, L C; Christou, G; Hendrickson, D N

    2001-12-03

    The preparation and physical characterization are reported for the single-molecule magnet salts [M(Cp')(2)](n)()[Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)] (M = Fe, n = 1, Cp' = C(5)Me(5) (2a), C(5)H(5) (2b); M = Co, n = 1, Cp' = C(5)Me(5) (2c), C(5)H(5) (2d); M = Fe, n = 2, Cp' = C(5)Me(5) (2e), C(5)H(5) (2f)) to investigate the effects of paramagnetic cations on the magnetization relaxation behavior of [Mn(12)]- anionic single-molecule magnets. Complex 2a.2H(2)O crystallizes in the orthorhombic space group Aba2, with cell dimensions at 173 K of a = 25.6292(2) A, b = 25.4201(3) A, c = 29.1915(2) A, and Z = 4. Complex 2c.2CH(2)Cl(2).C(6)H(14) crystallizes in the monoclinic space group P2(1)/c, with cell dimensions at 173 K of a = 17.8332(6) A, b = 26.2661(9) A, c = 36.0781(11) A, beta = 92.8907(3) degrees, and Z = 4. These two salts consist of either paramagnetic [Fe(C(5)Me(5))(2)]+ cations or diamagnetic [Co(C(5)Me(5))(2)]+ cations, and [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)]- anions. The structures of the anions in the two salts are similar, consisting of a central Mn(4)O(4) cubane moiety, surrounded by a nonplanar ring of eight Mn atoms that are bridged by and connected to the cube via mu(3)-O(2)- ions. The oxidation states of four Mn sites out of eight outer Mn ions in complex 2a were assigned to be +2.75 from the valence bond sum analysis although the disordering of bridging carboxylates prevents more precise determination. On the other hand in complex 2c, one Mn site out of eight outer Mn ions was identified as a Mn(II) ion, accommodating the "extra" electron; this was deduced by a valence bond sum analysis. Thus, the anion in complex 2c has a Mn(II)(1)Mn(III)(7)Mn(IV)(4) oxidation state description. The Jahn-Teller axes of the Mn(III) ions in both anions are roughly aligned in one direction. All complexes studied exhibit a single out-of-phase ac magnetic susceptibility (chi"(M)) signal in the 4.6-4.8 K range for complexes 2a-2d and in the 2.8-2.9 K range

  10. Bibliographic review and new measurements of the infrared band strengths of pure molecules at 25 K: H2O, CO2, CO, CH4, NH3, CH3OH, HCOOH and H2CO

    Science.gov (United States)

    Bouilloud, M.; Fray, N.; Bénilan, Y.; Cottin, H.; Gazeau, M.-C.; Jolly, A.

    2015-08-01

    Infrared observations of the interstellar medium revealed the presence of several molecules in the solid phase such as H2O, CO2, CO, CH4, NH3, CH3OH, H2CO and HCOOH. Measurements of column densities and molecular abundances relative to water require the knowledge of infrared band strengths. We present a review of refractive indices at visible wavelengths, densities and infrared band strengths for all eight molecules. We also present new band strengths measured on icy films whose thicknesses have been determined using laser interference techniques. For CO2, CO, CH4 and NH3, our measurements are in agreement with previous determinations taking into account an uncertainty of about 20 per cent. For H2O ice films, the porosity and the density remain unreliable, leading to large uncertainties on the measured band strengths. Concerning amorphous CH3OH, H2CO and HCOOH, the densities and refractive indices are unknown leading to large uncertainties on the band strengths. However, we propose new values that are slightly different from previous determination. Our review and experimental work point out the most reliable band strengths for the eight studied molecules. For CH4, CH3OH, HCOOH and H2CO, the band strengths used to calculate abundances in the ices of interstellar medium seem to be inaccurate, leading to some doubts on the determined values.

  11. Crystal packing and hydrogen bonding in platinum(II) nucleotide complexes: X-ray crystal structure of [Pt(MeSCH(2)CH(2)SMe)(5'-GMP-N7)(2)].6H(2)O.

    Science.gov (United States)

    Djuran, Milos I; Milinkovic, Snezana U; Habtemariam, Abraha; Parsons, Simon; Sadler, Peter J

    2002-02-01

    We have synthesised the complex [Pt(CH(3)SCH(2)CH(2)SCH(3))(5'-GMP-N7)(2)].6H(2)O (1), where 5'-GMP is 5'-guanosine monophosphate, and determined its X-ray crystal structure. Pt(II) adopts a square-planar geometry in which the bases are coordinated head-to-tail (HT) in the Delta configuration. The nucleotide conformation in this complex is almost identical to that in the previously reported complex [Pt(en)(5'-GMP-N7)(2)].9H(2)O (2), in which there is outer sphere macrochelation via intramolecular H-bonding between the monoanionic phosphate groups and the coordinated ethylenediamine (en) NH. It is therefore apparent that intermolecular interactions rather than intramolecular H-bonding determines the orientation of the sugar-phosphate side-chain in these Pt(II) bisnucleotide complexes in the solid state.

  12. An unprecedented copper(I,II)-octacyanotungstate(V) 2-D network: crystal structure and magnetism of [CuII(tren)]{CuI[W(V)(CN)8]} . 1.5H2O.

    Science.gov (United States)

    Korzeniak, Tomasz; Stadnicka, Katarzyna; Pelka, Robert; Balanda, Maria; Tomala, Krzysztof; Kowalski, Kazimierz; Sieklucka, Barbara

    2005-06-21

    A novel two-dimensional cyanide-bridged polymer [CuII(tren)]{CuI[W(V)(CN)8]} . 1.5H2O (tren = tris(2-aminoethyl)amine) formed via the simultaneous in situ metal-ligand redox reaction of [Cu(tren)(OH2)]2+ and self-assembly with [W(V)(CN)8]3- consists of a {CuI[W(V)(CN)8]} square grid built of CuI centres of tetrahedral geometry coordinatively saturated by CN bridges and [W(V)(CN)8]3- capped by [CuII(tren)]2+ moieties; it exhibits ferromagnetic coupling J1 = +5.8(1) cm(-1) within the CuII-W(V) dinuclear subunits and weak antiferromagnetic coupling J2 = -0.03(1) cm(-1) between them through diamagnetic CuI spacers.

  13. Tetrakis(thiadiazole)porphyrazines. 6. Spectroelectrochemical and density functional theory studies of the anions [TTDPzM](n-) (n = 1-4; M = Zn(II), Mg(II)(H(2)O), Cu(II), 2H(I)).

    Science.gov (United States)

    Donzello, Maria Pia; Ercolani, Claudio; Cai, Xiaohui; Kadish, Karl M; Ricciardi, Giampaolo; Rosa, Angela

    2009-10-19

    Following previous cyclic voltammetric studies of tetrakis(thiadiazole)porphyrazines [TTDPzM] where M = Zn(II), Mg(II)(H(2)O), Cu(II), or 2H(I) in nonaqueous media, a thin-layer spectroelectrochemical investigation was carried out in pyridine to characterize each stepwise one-electron reduction of the electrogenerated [TTDPzM](n-) complexes where n = 1-4. A similar UV-visible spectrum was observed for each form of the anion, independent of the central metal ion and detailed theoretical calculations by density functional theory (DFT) and time-dependent DFT (TDDFT) methods were applied to interpret the spectral features of [TTDPzZn](n-) (n = 1-4) which was selected as representative for describing the ground and excited-state electronic structures of the entire [TTDPzM](n-) series. The use of two exchange-correlation functionals, the pure, asymptotically correct statistical average of orbital potentials (SAOP) and the hybrid B3LYP functionals, proved to be essential for attaining a correct assignment of the key spectral features. The nature and intensity of the main spectral features are highlighted and interpreted on the basis of the ground-state electronic structure of the complexes.

  14. Angiotensin(1-7) attenuated Angiotensin II-induced hepatocyte EMT by inhibiting NOX-derived H2O2-activated NLRP3 inflammasome/IL-1β/Smad circuit.

    Science.gov (United States)

    Zhang, Li-Li; Huang, Shan; Ma, Xiao-Xin; Zhang, Wen-Yong; Wang, Dan; Jin, Si-Yi; Zhang, Yan-Ping; Li, Yang; Li, Xu

    2016-08-01

    Epithelial-mesenchymal transition (EMT) is correlated with NAPDH oxidase (NOX)-derived reactive oxygen species (ROS). The ROS-induced NOD-like receptor pyrin domain containing-3 (NLRP3) inflammasome is a novel mechanism of EMT. Angiotensin II (AngII) induces EMT by regulating intracellular ROS. Nevertheless, it has not been reported whether AngII could induce hepatocyte EMT. Angiotensin-(1-7) [Ang-(1-7)] can inhibit the effects of AngII via a counter-regulatory mechanism. However, whether Ang-(1-7) attenuated the effects of AngII on hepatocyte EMT remains unclear. The aim of this study was to determine whether Ang-(1-7) attenuated AngII-induced hepatocyte EMT by inhibiting the NOX-derived ROS-mediated NLRP3 inflammasome/IL-1ß/Smad circuit. In vivo, two animal models were established. In the first model, rats were infused AngII. In the second model, Ang-(1-7) was constantly infused into double bile duct ligated (BDL) rats. In vitro, hepatocytes were pretreated with antioxidant, NLRP3 siRNA, NOX4 siRNA, or Ang-(1-7) before exposure to AngII. In vitro, AngII induced hepatocyte EMT, which was inhibited by N-acetylcysteine (NAC), diphenylene iodonium (DPI), and NOX4 siRNA. NLRP3 inflammasome, which was activated by hydrogen peroxide (H2O2), mediated AngII-induced hepatocyte EMT. Ang-(1-7) suppressed AngII-induced EMT by inhibiting the NOX-derived H2O2-activated NLRP3 inflammasome/IL-1ß/Smad circuit. In vivo, infusion of AngII induced activation of H2O2-correlated NLRP3 inflammasome in rat livers and accumulation of α-collagen I (Col1A1) in hepatocytes. Infusion of Ang-(1-7) alleviated BDL-induced liver fibrosis and inhibited the expression of Col1A1 and the activation of NLRP3 inflammasome in hepatocytes. Ang-(1-7) attenuated AngII-induced hepatocyte EMT by inhibiting the NOX-derived H2O2-activated NLRP3 inflammasome/IL-1ß/Smad circuit. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Dilithium disodium nickel(II) cyclo-hexa-phosphate dodeca-hydrate, Li(2)Na(2)NiP(6)O(18)·12H(2)O.

    Science.gov (United States)

    Abid, Sonia; Al-Deyab, Salem S; Rzaigui, Mohamed

    2012-08-01

    The crystal structure of Li(2)Na(2)NiP(6)O(18)·12H(2)O is characterized by the presence of six-membered P(6)O(18) (6-) phosphate ring anions (inter-nal symmetry -1) having a chair conformation and three different cations, viz. Li(+), Na(+) and Ni(2+), to counterbalance the anionic charge. All atoms are in general positions except for nickel, which lies on a special position with site symmetry 2. Lithium has a tetra-hedral environment (LiO(4)), and sodium and nickel have octa-hedral environments [NaO(6) and Ni(H(2)O)(6), respectively]. The P(6)O(18) rings are linked via corner sharing by NaO(6) octa-hedra and LiO(4) tetra-hedra to form a three-dimensional framework presenting tunnels running along [010] in which the six-coordinated Ni(2+) cations are located. The structure is stabilized by a network of O-H⋯O hydrogen bonds.

  16. KIRMIZI ÇAMURDAN DEMİR (II SÜLFAT (FeSO4.7H2 O ÜRETİMİ

    Directory of Open Access Journals (Sweden)

    Nihat TINKILIÇ

    1996-02-01

    Full Text Available Boksitten alüminyum üretiminde atık madde olarak ele geçen kırmızı çamur bünyesinde Fe, Al, Na, V ve Ti gibi kıymetli maddeler bulundurur. Bu çalışmada, sülfürik asit kullanılarak 170 o C 'de 3 saat süreyle çözünürleştirilen kırmızı çamur içindeki demir, uygulanan analitik işlemler sonucu % 86 verimle FeSO4.7H2 O şeklinde ayrıldı. Demir oranı düşük (%38,57 Fe2 O3 olması sebebiyle pik demir üretimi için uygun olmayan kırmızı çamurun FeSO4.7H2 O üretiminde kullanılabileceği sonucuna ulaşıldı.

  17. Thermal- and light-induced spin crossover in novel 2D Fe(II) metalorganic frameworks {Fe(4-PhPy)(2)[M(II)(CN)(x)](y)}.sH(2)O: spectroscopic, structural, and magnetic studies.

    Science.gov (United States)

    Seredyuk, M; Gaspar, A B; Ksenofontov, V; Verdaguer, M; Villain, F; Gütlich, P

    2009-07-06

    Five novel two-dimensional coordination polymers {Fe(4PhPy)(2)[M(II)(CN)(4)]}.sH(2)O (4PhyPy = 4-phenylpyridine; 1: M(II) = Pd, s = 0; 2: M(II) = Ni, s = 0; 3: M(II) = Pt, s = 1) and {Fe(4PhPy)(2)[M(I)(CN)(2)](2)}.sH(2)O (4: M(I) = Ag, s = 1; 5: M(I) = Au, s = 0.5) exhibiting spin-crossover properties have been synthesized. They were characterized at various temperatures using X-ray absorption spectroscopy (XAS), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and magnetic susceptibility measurements. The occurrence of a cooperative thermal spin transition detected by the magnetic method is located at critical temperatures T(c)( downward arrow)/T(c)( upward arrow) = 163 K/203 K (1), 135 K/158 K (2), and 172 K/221 K (3), and a less cooperative one is located at T(c) = 188 K (4) and 225 K (5). Compounds 1-5 show an abrupt color change from yellow (high-spin (HS) state) to red (low-spin (LS) state) upon spin-state conversion. The dehydration of the compounds changes the type of the spin transition, making it more abrupt and shifting the critical temperature to higher temperatures. For 1 and 2, XAS provides local structural information on the contraction of the FeN(6) coordination sphere upon the HS-to-LS transition, in line with the magnetic results. Variable-temperature characterization of 1 by X-ray diffraction evidences the very abrupt phase transition with a large hysteresis. A light-induced spin conversion (LIESST effect) is detected by magnetic measurements in 1-5 below 70 K.

  18. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?

    Science.gov (United States)

    Houtkooper, Joop M.; Schulze-Makuch, Dirk

    2007-08-01

    The discovery of extremophiles on Earth is a sequence of discoveries of life in environments where it had been deemed impossible a few decades ago. The next frontier may be the Martian surface environment: could life have adapted to this harsh environment? What we learned from terrestrial extremophiles is that life adapts to every available niche where energy, liquid water and organic materials are available so that in principle metabolism and propagation are possible. A feasible adaptation mechanism to the Martian surface environment would be the incorporation of a high concentration of hydrogen peroxide in the intracellular fluid of organisms. The H2O2-H2O hypothesis suggests the existence of Martian organisms that have a mixture of H2O2 and H2O instead of salty water as their intracellular liquid (Houtkooper and Schulze-Makuch, 2007). The advantages are that the freezing point is low (the eutectic freezes at 56.5°C) and that the mixture is hygroscopic. This would enable the organisms to scavenge water from the atmosphere or from the adsorbed layers of water molecules on mineral grains, with H2O2 being also a source of oxygen. Moreover, below its freezing point the H2O2-H2O mixture has the tendency to supercool. Hydrogen peroxide is not unknown to biochemistry on Earth. There are organisms for which H2O2 plays a significant role: the bombardier beetle, Brachinus crepitans, produces a 25% H2O2 solution and, when attacked by a predator, mixes it with a fluid containing hydroquinone and a catalyst, which produces an audible steam explosion and noxious fumes. Another example is Acetobacter peroxidans, which uses H2O2 in its metabolism. H2O2 plays various other roles, such as the mediation of physiological responses such as cell proliferation, differentiation, and migration. Moreover, most eukaryotic cells contain an organelle, the peroxisome, which mediates the reactions involving H2O2. Therefore it is feasible that in the course of evolution, water-based organisms

  19. Crystal structure of K0.75[FeII3.75FeIII1.25(HPO36]·0.5H2O, an open-framework iron phosphite with mixed-valent FeII/FeIII ions

    Directory of Open Access Journals (Sweden)

    Edurne S. Larrea

    2016-01-01

    Full Text Available Single crystals of the title compound, potassium hexaphosphitopentaferrate(II,III hemihydrate, K0.75[FeII3.75FeIII1.25(HPO36]·0.5H2O, were grown under mild hydrothermal conditions. The crystal structure is isotypic with Li1.43[FeII4.43FeIII0.57(HPO36]·1.5H2O and (NH42[FeII5(HPO36] and exhibits a [FeII3.75FeIII1.25(HPO36]0.75− open framework with disordered K+ (occupancy 3/4 as counter-cations. The anionic framework is based on (001 sheets of two [FeO6] octahedra (one with point group symmetry 3.. and one with point group symmetry .2. linked along [001] through [HPO3]2− oxoanions. Each sheet is constructed from 12-membered rings of edge-sharing [FeO6] octahedra, giving rise to channels with a radius of ca 3.1 Å where the K+ cations and likewise disordered water molecules (occupancy 1/4 are located. O...O contacts between the water molecule and framework O atoms of 2.864 (5 Å indicate hydrogen-bonding interactions of medium strength. The infrared spectrum of the compound shows vibrational bands typical for phosphite and water groups. The Mössbauer spectrum is in accordance with the presence of FeII and FeIII ions.

  20. Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC. Crystal structure of [Cu(PLITSC−HH2O]Br•H2O

    Directory of Open Access Journals (Sweden)

    Leovac Vukadin M.

    2014-01-01

    Full Text Available The synthesis and structural characterization of a square-planar copper(II complex with pyridoxal S-methylisothiosemicarbazone (PLITSC of the formula [Cu(PLITSC−HH2O]Br•H2O (1 as the first Cu(II complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSCBr2] (2 and [Cu(PLITSCBr(MeOH]Br (3 were characterized by elemental analysis, IR and electronic spectra and also by the methods of thermal analysis, conductometry and magnetochemistry. [Projekat Pokrajisnkog sekretarijata za nauku i tehnoloski razvoj Vojvodine i Ministarstva nauke Republike Srbije, br. 172014

  1. Impact of deformation energy on the hydrogen bonding interactions in gas phase 3-X catechol ⋯ H2O complexes (X = H, F, Cl, Br): The effect of approach of a water molecule

    Science.gov (United States)

    Deb, Debojit Kumar; Sarkar, Biplab

    2016-06-01

    The conformations and nature of hydrogen bonding interactions for 3-X catechol ⋯ H2O (X = H, F, Cl, Br) has been investigated by ab initio MP2, CCSD(T), and density functional B3LYP, wB97XD and M06-2X methods. The changes in interaction energies due to deformation of the structures has been studied in detail. The intra- and intermolecular hydrogen bonding interactions due to the different direction of approach of water molecule have been discussed. A detailed natural bond orbital (NBO) analysis and the symmetry-adapted perturbation theory (SAPT) based energy decomposition analysis has been carried out to elucidate interaction strength and properties in these hydrogen bonded systems. The charge transfer percentage (CTP) has been derived which will be universally useful for correlating binding energy, deformation energy and the geometrical parameters such as angles, bond lengths, etc. for other systems as well.

  2. Photodissociation of water. II. Wave packet calculations for the photofragmentation of H2O and D2O in the B˜ band

    Science.gov (United States)

    van Harrevelt, Rob; van Hemert, Marc C.

    2000-04-01

    A complete three-dimensional quantum mechanical description of the photodissociation of water in the B˜ band, starting from its rotational ground state, is presented. In order to include B˜-X˜ vibronic coupling and the B˜-Ã Renner-Teller coupling, diabatic electronic states have been constructed from adiabatic electronic states and matrix elements of the electronic angular momentum operators, following the procedure developed by A. J. Dobbyn and P. J. Knowles [Mol. Phys. 91, 1107 (1997)], using the ab initio results discussed in the preceding paper. The dynamics is studied using wave packet methods, and the evolution of the time-dependent wave function is discussed in detail. Results for the H2O and D2O absorption spectra, OH(A)/OH(X) and OD(A)/OD(X) branching ratios, and rovibrational distributions of the OH and OD fragments are presented and compared with available experimental data. The present theoretical results agree at least qualitatively with the experiments. The calculations show that the absorption spectrum and the product state distributions are strongly influenced by long-lived resonances on the adiabatic B˜ state. It is also shown that molecular rotation plays an important role in the photofragmentation process, due to both the Renner-Teller B˜-X˜ mixing, and the strong effect of out-of-plane molecular rotations (K>0) on the dynamics at near linear HOH and HHO geometries.

  3. One-pot synthesis of an Mn(III)-Cu(II)-Mn(III) trinuclear heterometallic compound formed by Mn$\\cdots$S-Cu-S$\\cdots$Mn supramolecular interactions: Crystal structure of [{MnIII(salph)(H2O)}2{CuII(mnt)2}]$\\cdot$4DMF

    Indian Academy of Sciences (India)

    Vedichi Madhu; Samar K Das

    2006-11-01

    A one-pot synthesis, that includes CuCl2$\\cdot$2H2O, Na2mnt, H2salph and Mn(CH3COO)3$\\cdot$H2O, leads to the isolation of a trinuclear heterometallic compound [{MnIII(salph)(H2O)}2{CuII(mnt)2}]$\\cdot$4DMF (1) formed by Mn$\\cdots$S-Cu-S$\\cdots$Mn supramolecular interactions. Compound 1 crystallizes in the monoclinic space group 21/ with = 13.433(4), = 16.283(5), = 15.072(4) Å, = 107.785(4)°, = 2. In the crystal structure, the complex anion [CuII(mnt)2]2- bridges two [MnIII(salph)(H2O)]1+ cations through Mn$\\cdots$S contacts. The non-covalent hydrogen bonding and - interactions among the trinuclear [{MnIII(salph)(H2O)}2{CuII(mnt)2}] complexes lead to an extended chain-like arrangement of [MnIII(salph) (H2O)]1+ cations with [CuII(mnt)2]2- anions embedded in between these chains.

  4. Geometrical structures, vibrational frequencies, force constants and dissociation energies of isotopic water molecules (H2O, HDO, D2O, HTO, DTO, and T2O) under dipole electric field

    Institute of Scientific and Technical Information of China (English)

    Shi Shun-Ping; Zhang Quan; Zhang Li; Wang Rong; Zhu Zheng-He; Jiang Gang; Fu Yi-Bei

    2011-01-01

    The dissociation limits of isotopic water molecules are derived for the ground state. The equilibrium geometries,the vibrational frequencies, the force constants and the dissociation energies for the ground states of all isotopic water molecules under the dipole electric fields from -0.05 a.u. to 0.05 a.u. are calculated using B3P86/6-311++G(3df,3pf).The results show that when the dipole electric fields change from -0.05 a.u. to 0.05 a.u., the bond length of H-O increases whereas the bond angle of H-O-H decreases because of the charge transfer induced by the applied dipole electric field. The vibrational frequencies and the force constants of isotopic water molecules change under the influence of the strong external torque. The dissociation energies increase when the dipole electric fields change from -0.05 a.u.to 0.05 a.u. and the increased dissociation energies are in the order of H2O, HDO, HTO, D2O, DTO, and T2O under the same external electric fields.

  5. Synthesis and Crystal Structure of a One-dimensional Azido-bridged Manganese (II) Compound [Mn(N3)2(H2O)3·C6H12N4]n

    Institute of Scientific and Technical Information of China (English)

    CHEN Hui; WANG Wen-Guo; ZHANG Xiao-Feng; CHEN Chang-Neng; LIU Qiu-Tian

    2006-01-01

    A new one-dimensional azido-bridged manganese compound has been prepared and structurally characterized by X-ray diffraction. The complex [Mn(N3)2(H2O)3·C6H12N4]n crystallizes in space group Pnma with a = 6.5252 (5), b = 9.3226(7), c = 22.2070(15)(A), V = 1350.89(17)(A)3, Z = 4, Mr = 333.24, Dc = 1.639 g/cm3, μ= 1.005 mm-1 and F(000) = 692. The final refinement gave R = 0.0328 and wR = 0.0777 for 1085 observed reflections with I > 2σ(I). The structure contains [Mn- (N3)2(H2O)3]n polymeric chains and uncoordinated hexamethylenetetramine (HMTA) molecules with Mn/HMTA molar ratio of 1:1. The Mn atoms are bridged by end-to-end azido ligands to construct one-dimensional zig-zag infinite chains. Each Mn atom is six-coordinated by three N atoms of three azido ligands and three water O atoms, resulting in an octahedral geometry. Extending hydrogen- bonding interactions involving water O atoms, azido and HMTA N atoms link the chains and HMTA molecules into a three-dimensional network.

  6. The study of H2O molecules adsorption on graphene armchair edge%H2O分子在石墨烯扶手型边缘吸附的研究

    Institute of Scientific and Technical Information of China (English)

    刘健康; 何国柱

    2012-01-01

    类似石墨表面,石墨烯可以吸附和脱附各种原子和分子,石墨烯比石墨具有更大表面积,因此,石墨烯的表面性能被广泛关注.然而较少被关注的是石墨烯边缘C原子的性能.石墨烯边缘C原子由于存在未配对的电子,因此具有更强的反应活性.本文采用了Self-Consistent-Charge Density Functional Tight Binding(SCC-DFTB)方法对H2O分子在石墨烯扶手型边缘的吸附现象进行了研究.研究发现,石墨烯边缘的峰位C原子具有很好的吸附性,吸附能大约为-0.109~-0.768 eV,明显大于石墨烯表面原子的吸附能(-0.018~-0.047eV).当H2O分子被吸附时,有电荷转移现象发生,使得H2O分子极性增强,增加了吸附性能.当H2O分子中的O原子朝向C原子时,H2O分子可与两个谷位C原子、两个峰位C原子形成环状物,是没有O-H键分解的吸附中最稳定的结构,有明显的电荷转移现象.%Like graphite, graphene can adsorb and dis-adsorb many molecules and atoms. Graphene has bigger surface, so it was widely researched by chemists. However, seldom studies are carried out for the edge atoms which are more active than the surface atoms due to unpaired electrons in graphene. In this paper, we applied the self-consistent-charge density functional tight binding (SCC-DFTB) method to probe the adsorption phenomenon on the graphene edge atoms. Our research found that the absorption energy of edge atoms ranges from —0.109 to —0. 768 eV, which is much larger than that of the surface atoms ( — 0. 018~-0. 047 eV). Through the analysis of the charge transfer we found that when H2O is adsorbed on C atoms, the charge transfer enhances the molecular polarity of H2O. When the O atom of H2O is toward the C atom of graphene, H2O and graphene form the ring structure, a best stable structure among the non-dissociation adsorptions.

  7. Synthesis and Crystal Structure of One-dimensional Chain Zinc(II) Coordination Polymer:{Na[ZnL(H2O)2]}n(L=2-Hydroxyl-2-hydroxylate-malonate Trivalent Anion)

    Institute of Scientific and Technical Information of China (English)

    石敬民; 朱思成; 吴长举

    2004-01-01

    A one-dimensional chain complex {Na[ZnL(H2O)2]}n was synthesized by sodium 2,2-dihydroxyl-malonate (Na2L′) and hydrate zinc perchlorate. The crystal belongs to the mono- clinic system, space group P21/n with a = 5.936(2), b = 7.203(3), c = 19.356(8) A,Z= 95.264(6)°, V = 824.2(6)A3, Z = 4, C3H5NaO8Zn, Mr = 257.43, Dc = 2.075 g/cm3, F(000) = 512 and ( = 3.045 mm-1. The structure was refined to R = 0.0381 and Wr = 0.0766 for 1188 observed reflections (I>2σ(I)). In the complex the zinc(II) atom is coordinated to six oxygen atoms from two H2O mole- cules, two carboxylate groups, one ionized hydroxyl group and one hydroxyl group. By the coordi- nation of zinc(II) ions and bridging ligand 2-hydroxyl-2-hydroxylate-malonate trivalent anion the one-dimensional chain is constructed.

  8. Design and construction of two rare aqua bridged copper (II) coordination polymers through mixed ligand strategy: Synthesis, characterization and single crystal X-ray structure determination of [Cu(2-iodobenzoate)2(β/γ-picoline)2(μ-H2O)]n

    Science.gov (United States)

    Kumar, Santosh; Sharma, Raj Pal; Saini, Anju; Venugopalan, Paloth; Ferretti, Valeria

    2015-03-01

    Reaction of hydrated copper (II) 2-iodobenzoate with β/γ-picoline in methanol:water mixture (4:1, v/v) yielded two rare aqua bridged zig-zag polymers [Cu(2-iodobenzoate)2(β-picoline)2(μ-H2O)]n; 1 and [Cu(2-iodobenzoate)2(γ-picoline)2(μ-H2O)]n; 2. The newly synthesized complexes have been characterized by elemental analysis, FT-IR spectroscopy, UV-Vis spectroscopy and single crystal X-ray structure determination. Complex 1 crystallized in monoclinic crystal system with C2/c space group, and complex 2 crystallized in triclinic crystal system with P 1 ‾ space group. X-ray structure determination revealed the presence of 1-dimensional chains of constituent molecules running along a-axis in both complexes. Water molecules act as bridges between constituent molecules and hence play a crucial role in 1-dimensional chain propagation in zig-zag manner. Empty channels have been observed between the zig-zag chains of complexes. Non-covalent interactions interactions such as O-H⋯O, C-H⋯O and C-H⋯π have been observed, which play a decisive role in the stabilization of crystal lattices in both complexes 1 and 2.

  9. Vibrational spectroscopic study of nickel(II) malonate, Ni(COO·CH 2·COO)·2H 2O and its aqueous solution

    Science.gov (United States)

    Bickley, R. I.; Edwards, H. G. M.; Knowles, A.; Gustar, R. E.; Mihara, D.; Rose, S. J.

    1993-07-01

    A vibrational spectroscopic study of nickel(II) malonate and its aqueous solution has been made. The vibrations characteristic of a malonato—nickel complex have been assigned and it is concluded that the species NiCH 2(COO) 2 exists in the solid state, with C2v symmetry and bidentate ligand-to-metal bonding. The Raman spectrum of a 0.01 M aqueous solution of nickel(II) malonate indicates that complete dissociation of the complex to the free malonate and nickel(II) hexaaquo ions occurs. Comparisons with other nickel(II) carboxylates have also been undertaken.

  10. Synthesis and Structure of a Novel Compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O

    Institute of Scientific and Technical Information of China (English)

    TANG Ding-Xing; ZHAO Yun

    2005-01-01

    A novel compound [Cu2(EDTA)(Py)2(H2O)2]·2H2O was synthesized by the reaction of CuSO4(5H2O with H4EDTA in pyridine/water (V/V = 1/4) solvent, and characterized by elemental analysis, IR spectrum and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 1.26974(6), b = 0.67949(3), c = 1.48548(3) nm, β = 91.454(2)o, V = 1.28122(9) nm3, Z = 2, Dc = 1.673 g/cm3, Mr = 645.56, F(000) = 664, μ(MoKα) = 1.729 mm-1, the final R = 0.0353 and wR = 0.0832 for 1920 observed reflections (I > 2((I)). The compound is a centrosymmetric binuclear molecule with bridged EDTA group. Each Cu(II) atom is linked to two oxygen atoms and one nitrogen atom of EDTA, one oxygen atom of water and one nitrogen atom of pyridine to form a distorted square pyramidal environment. There exist face-to-face π-π stacking interactions between pyridine rings from neighboring molecule with the interplanar distance of 0.3670 nm and hydrogen bonding between EDTA and water molecules.

  11. Crystal structures of [Mn(bdc(Hspar2(H2O0.25]·2H2O containing MnO6+1 capped trigonal prisms and [Cu(Hspar2](bdc·2H2O containing CuO4 squares (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate

    Directory of Open Access Journals (Sweden)

    Zhe An

    2016-01-01

    Full Text Available The syntheses and crystal structures of 0.25-aqua(benzene-1,4-dicarboxylato-κ2O,O′bis(sparfloxacin-κ2O,O′manganese(II dihydrate, [Mn(C8H4O4(C19H22F2N4O32(H2O0.25]·2H2O or [Mn(bdc(Hspar2(H2O0.25]·2H2O, (I, and bis(sparfloxacin-κ2O,O′copper(II benzene-1,4-dicarboxylate dihydrate, [Cu(C19H22F2N4O32](C8H4O4·2H2O or [Cu(Hspar2](bdc·2H2O, (II, are reported (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate. The Mn2+ ion in (I is coordinated by two O,O′-bidentate Hspar neutral molecules (which exist as zwitterions and an O,O′-bidentate bdc dianion to generate a distorted MnO6 trigonal prism. A very long bond [2.580 (12 Å] from the Mn2+ ion to a 0.25-occupied water molecule projects through a square face of the prism. In (II, the Cu2+ ion lies on a crystallographic inversion centre and a CuO4 square-planar geometry arises from its coordination by two O,O′-bidentate Hspar molecules. The bdc dianion acts as a counter-ion to the cationic complex and does not bond to the metal ion. The Hspar ligands in both (I and (II feature intramolecular N—H...O hydrogen bonds, which close S(6 rings. In the crystals of both (I and (II, the components are linked by N—H...O, O—H...O and C—H...O hydrogen bonds, generating three-dimensional networks.

  12. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

    Science.gov (United States)

    Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

    2013-01-01

    We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

  13. Crystal Structure and Characterization of the Dinuclear Cd(II Complex [Cd(H2O2(ο-HOC6H4COO2]2

    Directory of Open Access Journals (Sweden)

    Pusu Zhao

    2004-09-01

    Full Text Available The structure of a new binuclear cadmium (II complex, [Cd(H2O2(Sal2]2 (Sal= salicylate, has been determined by X-ray crystallography. It was also characterized byelemental analysis, its IR spectrum and thermogravimetric-differential scanningcalorimetry (TG-DSC. It crystallizes in the monoclinic system, space group P21/c, withlattice parameters a = 15.742(3 å, b = 12.451(3 å, c = 7.7225(15 å, β = 96.07(3o andZ = 4. Two cadmium (II ions are bridged by two μ2-carboxy oxygen atoms. Eachcadmium atom lies in a distorted capped octahedron coordination geometry. The thermalgravimetry (TG data indicate that there are four discrete decomposition steps with twoendothermic peaks and one exothermic peak. The final thermal decomposition product isCdO.

  14. A mixed Ni(II) ionic complex containing V-shaped water trimer: Synthesis, spectral, structural and thermal properties of {[Ni(2,2′-bpy)3][Ni(2-cpida)(2,2′ -bpy)]} (ClO4).3H2O

    Indian Academy of Sciences (India)

    Nallasamy Palanisami; Kabali Senthilkumar; Mohan Gopalakrishnan; Il-Shik Moon

    2015-05-01

    A mixed Ni(II) ionic complex of {[Ni(2,2′-bpy)3][Ni(2-cpida)(2,2′-bpy)]}(ClO4).3H2O (1) (2-H3cpida = N-(2-carboxyphenyl)iminodiacetic acid, 2,2′-bpy = 2,2′-bipyridyl) has been synthesized and characterized by infrared, ultraviolet and fluorescence spectroscopy, elemental and thermogravimetric analysis. The molecular structure of compound 1, as determined by single-crystal X-ray diffraction studies, showed all the three carboxylate groups are in monodendate mode. Compound 1 consists of a discrete mononuclear [Ni(2,2′-bpy)3]2+ cation, a [Ni(2-cpida)(2,2′-bpy)]− anion, a ClO$^{−}_{4}$ anion and three lattice water molecules. The H-bonding interaction between three lattice water molecule forms a V-shaped trimer (H2O)3 which gives rise to a 1-D polymeric structure in the solid state.

  15. On the XeF+/H2O System: Synthesis and Characterization of the Xenon (II) Oxide Fluoride Cation, FXeOXeFXeF+ (PREPRINT)

    Science.gov (United States)

    2009-06-30

    11 fluoride plays a two-fold role in influencing this equilibrium. There is the obvious mass effect expected from the Le Chatelier Principle ...the Xenon (II) Oxide Fluoride Cation, FXeOXeFXeF + (Preprint) 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) M. Gerken...AFRL/RZSP) 5e. TASK NUMBER 5f. WORK UNIT NUMBER 50260541 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) AND ADDRESS(ES) 8. PERFORMING

  16. Laser-induced positive ion and neutral atom/molecule emission from single-crystal CaHPO4.2H2O: The role of electron-beam-induced defects

    Science.gov (United States)

    Dawes, M. L.; Hess, W.; Kawaguchi, Y.; Langford, S. C.; Dickinson, J. T.

    We examine laser-induced ion and neutral emissions from single-crystal CaHPO4.2H2O (brushite), a wide-band-gap, hydrated inorganic single crystal, with 248-nm excimer laser radiation. Both laser-induced ion and neutral emissions are several orders of magnitude higher following exposure to 2 keV electrons at current densities of 200 μA/cm2 and doses of 1 C/cm2. In addition to intense Ca+ signals, electron-irradiated surfaces yield substantial CaO+, PO+, and P+ signals. As-grown and as-cleaved brushite show only weak neutral O2 and Ca emissions, whereas electron-irradiated surfaces yield enhanced O2, Ca, PO, PO2, and P emissions. Electron irradiation (i) significantly heats the sample, leading to thermal dehydration (CaHPO4 formation) and pyrolysis (Ca2P2O7 formation) and (ii) chemically reduces the surface via electron stimulated desorption. The thermal effects are accompanied by morphological changes, including recrystallization. Although complex, these changes lead to high defect densities, which are responsible for the dramatic enhancements in the observed laser desorption.

  17. Two New Octadecanuclear Copper(II)-Lanthanide(III) Clusters Encapsulating μ9-NO -3 Anions. Synthesis, Structures, and Magnetic Properties of [Cu 12Ln6( μ3-OH) 24(C 5H 5NCH 2CO 2) 12(H 2O) 18( μ9-NO 3)](PF 6) 10(NO 3) 7·12H 2O ( LnIII=Sm III or Gd III)

    Science.gov (United States)

    Yang, Yang-Yi; Chen, Xiao-Ming; Ng, Seik Weng

    2001-11-01

    Two new octadecanuclear clusters [Cu12Ln6(μ3-OH)24(C5H5NCH2CO2)12(H2O)18(μ9-NO3)](PF6)10(NO3)7·12H2O [LnIII=SmIII (1) or GdIII (2)] have been synthesized and characterized by X-ray diffraction. They are isomorphous and crystallize in the triclinic space group Poverline1 with Z=1. The cell dimensions of 1 are a=17.366(1), b=17.790(1), and c=19.002(1) Å, α=117.279(1), β=91.763(1), and γ=111.585(1)°. In the cluster, 6 SmIII atoms are positioned at the vertices of an octahedron, while 12 CuII atoms are at the midpoints of the edges of the octahedron. The CuII-SmIII metal framework is interconnected by the 24 similar μ3-OH- groups, each bridging one SmIII and two CuII atoms. The octahedral cage encapsulates an unusual μ9-NO-3 anion with each oxygen atom coordinated to three CuII atoms. The 12 carboxylate ligands act as μ2-carboxylate-O,O‧ bridges, each linking a SmIII and a CuII atom. The PF-6 counteranion plays an important role in crystallization of the two complexes.

  18. EPR and optical investigation of VO(II) in Zn(C3H3O4)2(H2O)2 single crystals: An interstitial site

    Science.gov (United States)

    Natarajan, B.; Mithira, S.; Deepa, S.; Sambasivarao, P.

    2007-10-01

    EPR spectroscopic investigations on single crystals of diaquabis[malonato(1-)-κ2O,O‧] zinc(II) doped with VO(II) ion have been carried out at X-band frequencies and at 300 K. The single crystal, rotated along the three mutually orthogonally axes, has yielded spin-Hamiltonian parameters g and A as: gxx=1.980, gyy=1.972, gzz=1.937 and Axx=8.4, Ayy=6.1, Azz=18.1 mT, respectively. These spin-Hamiltonian parameters reflect a slight deviation from axial symmetry to rhombic, which is elucidated by the interstitial occupation of vanadyl ions. The isofrequency plots and powder EPR spectrum have been simulated. The percentage of metal-oxygen bond has been estimated. The optical absorption spectrum exhibits four bands at 257, 592, 720 and 764 nm suggesting a C4v symmetry. The admixture coefficients and bonding parameters have also been calculated by collaborating EPR data with optical data.

  19. Destruction and Sequestration of H2O on Mars

    Science.gov (United States)

    Clark, Benton

    2016-07-01

    The availability of water in biologically useable form on any planet is a quintessential resource, even if the planet is in a zone habitable with temperature regimes required for growth of organisms (above -18 °C). Mars and most other planetary objects in the solar system do not have sufficient liquid water at their surfaces that photosynthesis or chemolithoautotrophic metabolism could occur. Given clear evidence of hydrous mineral alteration and geomorphological constructs requiring abundant supplies of liquid water in the past, the question arises whether this H2O only became trapped physically as ice, or whether there could be other, more or less accessible reservoirs that it has evolved into. Salts containing S or Cl appear to be ubiquitous on Mars, having been measured in soils by all six Mars landed missions, and detected in additional areas by orbital investigations. Volcanoes emit gaseous H2S, S, SO2, HCl and Cl2. A variety of evidence indicates the geochemical fate of these gases is to be transformed into sulfates, chlorides, chlorates and perchlorates. Depending on the gas, the net reaction causes the destruction of between one and up to eight molecules of H2O per atom of S or Cl (although hydrogen atoms are also released, they are lost relatively rapidly to atmospheric escape). Furthermore, the salt minerals formed often incorporate H2O into their crystalline structures, and can result in the sequestration of up to yet another six (sometimes, more) molecules of H2O. In addition, if the salts are microcrystalline or amorphous, they are potent adsorbents for H2O. In certain cases, they are even deliquescent under martian conditions. Finally, the high solubility of the vast majority of these salts (with notable exception of CaSO4) can result in dense brines with low water activity, aH, as well as cations which can be inimical to microbial metabolism, effectively "poisoning the well." The original geologic materials on Mars, igneous rocks, also provide some

  20. Synthesis and characterization of a chiral dimeric copper(II) complex: Crystal structure of [Cu2(-Cl)2(HL)2].H2O(H2L = -(-)-2-[(2-hydroxy-1-phenyl-ethylimino)-methyl]-phenol)

    Indian Academy of Sciences (India)

    Chullikkattil P Pradeep; Panthapally S Zacharias; Samar K Das

    2005-03-01

    Synthesis and characterization of an optically active binuclear dichloro-bridged copper(II) complex [Cu2(-Cl)2(HL)2]$\\cdot$H2O 1 (H2L = -(-)-2-[(2-hydroxy-1-phenyl-ethylimino)-methyl]-phenol) of a Schiff-base derived from salicylaldehyde and ()-(+)-2-phenylglycinol are described. Compound 1 crystallizes in the orthorhombic chiral P212121 space group with = 4, = 10.21(2), = 11.574(3), = 25.364(9). Each copper shows square pyramidal geometry with O2NCl2 coordination and the Cu2Cl2 core geometry adopts a butterfly shape. Crystals of 1 were further characterized by elemental analysis, IR, UV-visible and EPR spectroscopy and circular dichroism (CD) studies.

  1. CO diffusion into amorphous H2O ices

    CERN Document Server

    Lauck, Trish; Shulenberger, Katherine; Rajappan, Mahesh; Oberg, Karin I; Cuppen, Herma M

    2015-01-01

    The mobility of atoms, molecules and radicals in icy grain mantles regulate ice restructuring, desorption, and chemistry in astrophysical environments. Interstellar ices are dominated by H2O, and diffusion on external and internal (pore) surfaces of H2O-rich ices is therefore a key process to constrain. This study aims to quantify the diffusion kinetics and barrier of the abundant ice constituent CO into H2O dominated ices at low temperatures (15-23 K), by measuring the mixing rate of initially layered H2O(:CO2)/CO ices. The mixed fraction of CO as a function of time is determined by monitoring the shape of the infrared CO stretching band. Mixing is observed at all investigated temperatures on minute time scales, and can be ascribed to CO diffusion in H2O ice pores. The diffusion coefficient and final mixed fraction depend on ice temperature, porosity, thickness and composition. The experiments are analyzed by applying Fick's diffusion equation under the assumption that mixing is due to CO diffusion into an i...

  2. Study of the transient "free" OH radical generated in H2O-H2O2 mixtures by stimulated Raman scattering

    Science.gov (United States)

    Li, Fangfang; Ma, Zhiwei; Wang, Shenghan; Li, Tianyu; Sun, Chenglin; Li, Zhanlong; Men, Zhiwei

    2017-03-01

    Forward and backward stimulated Raman scattering (SRS) were studied in the H2O2-H2O mixtures by a strong excitation laser with 532 nm. Only the backward SRS (BSRS) of the H2O2-H2O system shows an unexpected SRS shoulder peak at around 3600 cm- 1, which is similar to the characteristic peak of "free" OH radical. The generation of the "free" OH radical is mainly attributed to the dissociation of hydrogen peroxide (HP) molecules. Simultaneously, the ionization of HP-water clusters generates a part of "free" OH radical under the Laser-induced breakdown (LIB). The interaction of water and HP is also discussed.

  3. Channels with ordered water and bipyridine mol-ecules in the porous coordination polymer {[Cu(SiF6)(C10H8N2)2]·2C10N2H8·5H2O} n.

    Science.gov (United States)

    Aubert, Emmanuel; Doudouh, Abdelatif; Peluso, Paola; Mamane, Victor

    2016-11-01

    The coordination polymer {[Cu(SiF6)(C10H8N2)2]·2C10H8N2·5H2O} n , systematic name: poly[[bis-(μ2-4,4'-bi-pyridine)(μ2-hexa-fluorido-silicato)copper(II)] 4,4'-bi-pyridine disolvate penta-hydrate], contains pores which are filled with water and 4,4'-bi-pyridine mol-ecules. As a result of the presence of these ordered species, the framework changes its symmetry from P4/mmm to P21/c. The 4,4'-bi-pyridine guest mol-ecules form chains inside the 6.5 × 6.9 Å pores parallel to [100] in which the mol-ecules inter-act through π-π stacking. Ordered water mol-ecules form infinite hydrogen-bonded chains inside a second pore system (1.6 × 5.3 Å free aperture) perpendicular to the 4,4'-bi-pyridine channels.

  4. Ni3Cl2.1(OH)3.9·4H2O, the Ni analogue to Mg3Cl2(OH)4·4H2O.

    Science.gov (United States)

    Bette, Sebastian; Dinnebier, Robert E; Freyer, Daniela

    2014-05-05

    For the first time a basic transition-metal hydrate, Ni3Cl2.1(OH)3.9·4H2O, is found to be isostructural to a main-group metal phase, Mg3Cl2.0(OH)4.0·4H2O. The Ni phase was found as crystalline solid in the course of investigations into the formation of basic nickel(II) chloride phases at 25 and 40 °C in alkaline, concentrated nickel(II) chloride solutions. Ni3Cl2.1(OH)3.9·4H2O was characterized by thermal analysis, IR spectroscopy, scanning electron microscopy, and X-ray powder diffraction. The crystal structure was determined from high-resolution laboratory X-ray powder diffraction data. Ni3Cl2.1(OH)3.9·4H2O crystallizes in space group C2/m (12) with Z = 2, a = 14.9575(4) Å, b = 3.1413(1) Å, c = 10.4818(5) Å, β = 101.482(1)°, and V = 482.50(3) Å(3). The main building unit of the structure is an infinite triple chain of edge-linked distorted NiO6 octahedra. These chains are separated by interstitial one-dimensional zigzag chains of disordered Cl(-) ions and H2O molecules. The crystal structures of Ni3Cl2.1(OH)3.9·4H2O and the isostructural magnesium salt hydrate Mg3Cl2(OH)4·4H2O (2-1-4 phase) are compared in detail.

  5. 一种镧系-过渡金属二维氰桥配合物[Nd(DMSO)2(H2O)2][Ni(CN)4]Cl(DMSO=二甲亚砜)的合成和晶体结构%Synthesis and Crystal Structure of a Cyano-Bridged Lanthanide-Transition-Metal Complex [Nd(DMSO)2(H2O)2][Ni(CN)4]Cl (DMSO=Dimethylsulfoxide) with Two-dimensional Gridding Molecule Structure

    Institute of Scientific and Technical Information of China (English)

    梁淑惠; 车云霞; 郑吉民

    2005-01-01

    The cyano-bridged bimetallic complex [Nd(DMSO)2(H2O)2][Ni(CN)4]Cl with two-dimensional gridding molecule structure was synthesized and characterized. In the complex all four cyano groups of unit Ni(CN)42- are bound to Nd3+ ions. The crystal data for the title complex: monoclinic, space group P21/c, a=0.780 0(3) nm,b=1.5097(6) nm, c=1.683 2(6) nm, β=115.231(14)°, Z=4, μ=4.311 mm-1, final R1=0.020 9, wR2=0.045 4. CCDC:272214.

  6. ISORROPIA II: a computationally efficient thermodynamic equilibrium model for K+─Ca²+─Mg²+─NH4+─Na+─SO4²-─NO3-─Cl-─H2O aerosols

    Directory of Open Access Journals (Sweden)

    C. Fountoukis

    2007-09-01

    Full Text Available This study presents ISORROPIA II, a thermodynamic equilibrium model for the K+–Ca2+–Mg2+–NH4+–Na+–SO42−–NO3−–Cl−–H2O aerosol system. A comprehensive evaluation of its performance is conducted against water uptake measurements for laboratory aerosol and predictions of the SCAPE2 thermodynamic module over a wide range of atmospherically relevant conditions. The two models agree well, to within 13% for aerosol water content and total PM mass, 16% for aerosol nitrate and 6% for aerosol chloride and ammonium. Largest discrepancies were found under conditions of low RH, primarily from differences in the treatment of water uptake and solid state composition. In terms of computational speed, ISORROPIA II was more than an order of magnitude faster than SCAPE2, with robust and rapid convergence under all conditions. The addition of crustal species does not slow down the thermodynamic calculations (compared to the older ISORROPIA code because of optimizations in the activity coefficient calculation algorithm. Based on its computational rigor and performance, ISORROPIA II appears to be a highly attractive alternative for use in large scale air quality and atmospheric transport models.

  7. Variations in H2O+/H2O ratios toward massive star-forming regions

    CERN Document Server

    Wyrowski, F; Herpin, F; Baudry, A; Bontemps, S; Chavarria, L; Frieswijk, W; Jacq, T; Marseille, M; Shipman, R; van Dishoeck, E F; Benz, A O; Caselli, P; Hogerheijde, M R; Johnstone, D; Liseau, R; Bachiller, R; Benedettini, M; Bergin, E; Bjerkeli, P; Blake, G; Braine, J; Bruderer, S; Cernicharo, J; Codella, C; Daniel, F; di Giorgio, A M; Dominik, C; Doty, S D; Encrenaz, P; Fich, M; Fuente, A; Giannini, T; Goicoechea, J R; de Graauw, Th; Helmich, F; Herczeg, G J; Jørgensen, J K; Kristensen, L E; Larsson, B; Lis, D; McCoey, C; Melnick, G; Nisini, B; Olberg, M; Parise, B; Pearson, J C; Plume, R; Risacher, C; Santiago, J; Saraceno, P; Tafalla, M; van Kempen, T A; Visser, R; Wampfler, S; Yıldız, U A; Black, J H; Falgarone, E; Gerin, M; Roelfsema, P; Dieleman, P; Beintema, D; De Jonge, A; Whyborn, N; Stutzki, J; Ossenkopf, V

    2010-01-01

    Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2O and H2O+ lines at 1113.3 and 1115.2 GHz using the Herschel Space Observatory toward a sample of high-mass star-forming regions to observationally study the relation between H2O and H2O+ . Nine out of ten sources show absorption from H2O+ in a range of environments: the molecular clumps surrounding the forming and newly formed massive stars, bright high-velocity outflows associated with the massive protostars, and unrelated low-density clouds along the line of sight. Column densities per velocity component of H2 O+ are found in the range of 10^12 to a few 10^13 cm-2 . The highest N(H2O+) column densities are found in the outflows of the sources. The ratios of H2O+/H2O are determined in a range from 0.01 to a few and are found to differ strongly between the observed environments with much lower ratios in the massive (proto)cluster e...

  8. Novel transition metal oxalatophosphates with a two-dimensional honeycomb structure: (H3TREN)[M2(HPO4)(C2O4)2.5] x 3H2O (M = Mn(II) and Fe(II), TREN = tris(2-aminoethyl)amine).

    Science.gov (United States)

    Jiang, Yau-Chen; Wang, Sue-Lein; Lee, Shang-Fan; Lii, Kwang-Hwa

    2003-10-06

    Two new layered transition metal oxalatophosphates, (H(3)TREN)[M(2)(HPO(4))(C(2)O(4))(2.5)].3H(2)O (M = Mn(II) and Fe(II)), have been synthesized by hydrothermal methods in the presence of a structure-directing organic amine, tris(2-aminoethyl)amine, and characterized by single-crystal X-ray diffraction and magnetic susceptibility. They are the first metal oxalatophosphates which adopt a two-dimensional honeycomb structure with the organic cations and water molecules intercalated in between. Within a layer, there are 12-membered pores made from 6 Mn, 1 phosphate, and 5 oxalate units. Measurements of field dependence of magnetization and variable-temperature susceptibilities under different fields were performed on a polycrystalline sample of the manganese compound. The results indicate a phase transition from a paramagnetic to an antiferromagnetic coupled state at about 12 K. Crystal data for the manganese compound follow: triclinic, space group Ponemacr; (No. 2), a = 8.8385(6) A, b = 9.0586(6) A, c = 16.020(1) A, alpha = 77.616(1) degrees, beta = 83.359(1) degrees, gamma = 68.251(1) degrees, and Z = 2. Crystal data for the iron compound are the same as those for the manganese compound except a = 8.7776(9) A, b = 8.9257(9) A, c = 15.884(2) A, alpha = 78.630(2) degrees, beta = 84.018(2) degrees, and gamma = 67.372(2) degrees.

  9. Treatment of wastewater from chIor-aIkaIi chemicaI industriaI park by sand fiItration+O3+ABAF+UV/H2O2 process%砂滤+O3+ABAF+UV/H2O2工艺处理氯碱化工园区污水

    Institute of Scientific and Technical Information of China (English)

    毕卫军; 陈海燕; 宋宁宁; 崔明勇

    2015-01-01

    采用连续流砂滤+O3+ABAF+UV/H2O2工艺处理以氯碱化工为主的某化工区废水,处理水量10000 m3/d,进水水质为COD≤200 mg/L、氨氮≤25 mg/L,经调整pH、碱度等运行参数,处理后出水达到《污水综合排放标准》(GB 8978—1996)一级A排放标准要求。%The continuous sand filtration+O3+ABAF+UV/H2O2 process has been applied to the treatment of the wastewater from a chemical industrial park,mainly chlor-alkali chemical industry. Water volume to be treated is 10 000 m3/d,COD in influent≤200 mg/L,NH3-N≤25 mg/L. After pH,alkalinity and other parameters are adjusted,the treated effluent can meet the requirements for level A of the first class of Integrated Wastewater Discharge Standard (GB 8978—1996).

  10. Structural flexibility and role of vicinal 2-thienyl rings in 2,3-dicyano-5,6-di(2-thienyl)-1,4-pyrazine, [(CN)2Th2Pyz], its palladium(II) complex [(CN)2Th2Pyz(PdCl2)2], and the related pentametallic pyrazinoporphyrazines [(PdCl2)4Th8TPyzPzM] (M = Mg(II)(H2O), Zn(II)).

    Science.gov (United States)

    Donzello, Maria Pia; De Mori, Giorgia; Viola, Elisa; Ercolani, Claudio; Bodo, Enrico; Mannina, Luisa; Capitani, Donatella; Rizzoli, Corrado; Gontrani, Lorenzo; Aquilanti, Giuliana; Kadish, Karl M; D'Angelo, Paola

    2011-12-05

    The solid state and solution structure of 2,3-dicyano-5,6-di(2-thienyl)-1,4-pyrazine, [(CN)(2)Th(2)Pyz], and its Pd(II) derivative, [(CN)(2)Th(2)Pyz(PdCl(2))(2)]·H(2)O, formed by reaction of [(CN)(2)Th(2)Pyz] with [(C(6)H(5)CN)(2)PdCl(2)] were characterized by X-ray, UV-visible, (1)H and (13)C NMR, and extended X-ray absorption fine structure (EXAFS) spectral measurements. The X-ray crystal structure of [(CN)(2)Th(2)Pyz] shows the presence of one thienyl ring positioned orthogonal to the rest of the molecule, with the two vicinal thienyl rings lying orthogonal to each other in a rare arrangement. NMR studies of [(CN)(2)Th(2)Pyz] in the solid state and in solutions of dimethylformamide or dimethyl sulfoxide confirm a nonequivalence of the thienyl rings in the solid state and also in solution. EXAFS results indicate that two distinct Pd(II) coordination sites are formed at the di(2-thienyl)pyrazino moiety of [(CN)(2)Th(2)Pyz(PdCl(2))(2)]·H(2)O, with identical Pd-N(pyz) (2.03(3) Å) and Pd-Cl (2.36(3) Å) bond lengths but with different Pd-S1 (2.25(4) Å) and Pd-S2 (3.21(5) Å) bond distances in an overall asymmetric molecular framework. Density functional theory (DFT) and time-dependent DFT (TDDFT) theoretical studies also provide information about the structure and spectral behavior of the precursor and its metalated Pd(II) derivative. (1)H/(13)C NMR and UV-visible spectral measurements were also carried out on two heteropentametallic porphyrazine macrocycles which were prepared by a reaction of PdCl(2) with [Th(8)TPyzPzM] where Th(8)TPyzPz = tetrakis-2,3-[5,6-di-(2-thienyl)-pyrazino]porphyrazinato dianion and M = Mg(II)(H(2)O) or Zn(II). Spectroscopic data on the newly synthesized [(PdCl(2))(4)Th(8)TPyzPzM] compounds suggest that the binding of PdCl(2) involves coordination sites of the type S(2(th))PdCl(2) with the two thienyl rings of each di(2-thienyl)pyrazino fragment bound to Pd(II) in an equivalent manner ("th-th" coordination). This is similar to what was

  11. A pure inorganic 1D chain based on {Mo8O28} clusters and Mn(II) ions: [Mn(H2O)2Mo8O28 ] n 6 n -

    Science.gov (United States)

    Zhang, Xiaofen; Yan, Yonghong; Wu, Lizhou; Yu, Chengxin; Dong, Xinbo; Hu, Huaiming; Xue, Ganglin

    2016-01-01

    A new pure inorganic polymer, (NH4)6n[Mn(H2O)2Mo8O28)]n(H2O)2n(1), has been synthesized and characterized by elemental analyses, IR spectrum, UV-vis absorption spectra, TG-DSC and electrochemical studies. In 1, [Mo8O28]8- anions act as tetradentate ligands and are alternately linked by Mn(H2O)2 2 + ions into a one-dimensional chain structure. It is interesting that 1 represents the first example of pure inorganic-inorganic hybrid based on octamolybdate and transition metal ions. Moreover, it was indicated that 1 had definite catalytic activities on the probe reaction of benzyl alcohol oxidation to benzaldehyde with H2O2.

  12. I + (H2O)2 → HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.

    Science.gov (United States)

    Wang, Hui; Li, Guoliang; Li, Qian-Shu; Xie, Yaoming; Schaefer, Henry F

    2016-03-03

    The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 → HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH → I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH → I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O → HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.

  13. Ultrafast Librational Relaxation of H2O in Liquid Water

    DEFF Research Database (Denmark)

    Petersen, Jakob; Møller, Klaus Braagaard; Rey, Rossend

    2013-01-01

    The ultrafast librational (hindered rotational) relaxation of a rotationally excited H2O molecule in pure liquid water is investigated by means of classical nonequilibrium molecular dynamics simulations and a power and work analysis. This analysis allows the mechanism of the energy transfer from...... the excited H2O to its water neighbors, which occurs on a sub-100 fs time scale, to be followed in molecular detail, i.e., to determine which water molecules receive the energy and in which degrees of freedom. It is found that the dominant energy flow is to the four hydrogen-bonded water partners in the first...... hydration shell, dominated by those partners’ rotational motion, in a fairly symmetric fashion over the hydration shell. The minority component of the energy transfer, to these neighboring waters’ translational motion, exhibits an asymmetry in energy reception between hydrogen-bond-donating and -accepting...

  14. Sulfitos duplos contendo cobre (I e um metal de transição M(II tipo Cu2SO3.M(IISO3.2H 2O [M(II = Cu(II, Fe(II, Mn(II e Cd(II]: preparação e seletividade na incorporação de M(II Double sulfite containing copper (I and a metal transition M(II like Cu2SO3.M(IISO3.2H 2O [M(II = Cu(II, Fe(II, Mn(II and Cd(II]: synthesis and selectivity in M(II incorporation

    Directory of Open Access Journals (Sweden)

    Luciana Almeida Silva

    1998-04-01

    Full Text Available The metal-catalyzed autooxidation of S(IV has been studied for more than a century without a consensus being obtained as to reaction rates, rate laws or mechanisms. The main objective in this work was to explore the reaction between Cu(II and SO2 in the presence of M(II, paying special attention to the formation of double sulfites like Cu2SO3.M(IISO3.2H 2O. The two principal aspects studied were: i a new way to prepare double sulfites with high purity degree and the selectivity in the M(II incorporation during the salt formation.

  15. EPA H2O Software Tool

    Science.gov (United States)

    EPA H2O allows user to: Understand the significance of EGS in Tampa Bay watershed; visually analyze spatial distribution of the EGS in Tampa Bay watershed; obtain map and summary statistics of EGS values in Tampa Bay watershed; analyze and compare potential impacts of development...

  16. EPA H2O User Manual

    Science.gov (United States)

    EPA H2O is a software tool designed to support research being conducted in the Tampa Bay watershed to provide information, data, and approaches and guidance that communities can use to examine alternatives when making strategic decisions to support a prosperous and environmentall...

  17. Theoretical Modeling of Water Exchange on [Pd(H(2)O)(4)](2+), [Pt(H(2)O)(4)](2+), and trans-[PtCl(2)(H(2)O)(2)].

    Science.gov (United States)

    Deeth, Robert J.; Elding, Lars I.

    1996-08-14

    Density functional theory is applied to modeling the exchange in aqueous solution of H(2)O on [Pd(H(2)O)(4)](2+), [Pt(H(2)O)(4)](2+), and trans-[PtCl(2)(H(2)O)(2)]. Optimized structures for the starting molecules are reported together with trigonal bipyramidal (tbp) systems relevant to an associative mechanism. While a rigorous tbp geometry cannot by symmetry be the actual transition state, it appears that the energy differences between model tbp structures and the actual transition states are small. Ground state geometries calculated via the local density approximation (LDA) for [Pd(H(2)O)(4)](2+) and relativistically corrected LDA for the Pt complexes are in good agreement with available experimental data. Nonlocal gradient corrections to the LDA lead to relatively inferior structures. The computed structures for analogous Pd and Pt species are very similar. The equatorial M-OH(2) bonds of all the LDA-optimized tbp structures are predicted to expand by 0.25-0.30 Å, while the axial bonds change little relative to the planar precursors. This bond stretching in the transition state counteracts the decrease in partial molar volume caused by coordination of the entering water molecule and can explain qualitatively the small and closely similar volumes of activation observed. The relatively higher activation enthalpies of the Pt species can be traced to the relativistic correction of the total energies while the absolute DeltaH() values for exchange on [Pd(H(2)O)(4)](2+) and [Pt(H(2)O)(4)](2+) are reproduced using relativistically corrected LDA energies and a simple Born model for hydration. The validity of the latter is confirmed via some simple atomistic molecular mechanics estimates of the relative hydration enthalpies of [Pd(H(2)O)(4)](2+) and [Pd(H(2)O)(5)](2+). The computed DeltaH() values are 57, 92, and 103 kJ/mol compared to experimental values of 50(2), 90(2), and 100(2) kJ/mol for [Pd(H(2)O)(4)](2+), [Pt(H(2)O)(4)](2+), and trans-[PtCl(2)(H(2)O)(2

  18. Lattice water molecules tuned spin-crossover for an iron(II) complex with thermal hysteresis.

    Science.gov (United States)

    Luo, Yang-Hui; Yang, Li-Jing; Liu, Qing-Ling; Ling, Yang; Wang, Wei; Sun, Bai-Wang

    2014-11-28

    A new iron(II) complex based on the 4,4'-dimethyl-2,2'-bipyridine ligand [Fe(4,4'-dmbpy)3(ClO4)(SCN)·3H2O (1·3H2O)] has been prepared and characterized. Structural studies and Hirshfeld surface analysis for complex 1·3H2O at three different temperatures (300, 240 and 130 K) are described. The UV-vis absorption spectrum of a water-free sample (1) in methanol solution and magnetic susceptibility measurements for solid-state samples 1·3H2O and 1 revealed that the removal of lattice water molecules from complex 1·3H2O changed the magnetic properties from the low-spin state (1·3H2O) to the complete spin-crossover (1) between 350-220 K with a thermal hysteresis of 7 K, and was accompanied by a colour change from brown to red.

  19. Synthesis and Properties of New Molecule-Based Magnets Containing Mn(II, Cu(II and Nitronyl Nitroxide Radical Cation

    Directory of Open Access Journals (Sweden)

    Vaz Maria G. F.

    2002-01-01

    Full Text Available In this work, we describe the synthesis of two new copper(II compounds, (Pr-Rad2 [Cu(opba].H2O (1 and (Bu-Rad2[Cu(opba].2H2O (2 where opba stands for ortho-phenylenebis(oxamato and RRad+ are nitronyl nitroxide radical cations. From 1 and 2, two new molecule-based magnets [Pr-Rad]2[Mn2{Cu(opba}3 ].3.3DMSO.5H2O (3 and [Bu-Rad]2 [Mn2{Cu(opba}3].3DMSO.6H 2O (4 were obtained, respectively. The magnetic properties of precursors 1 and 2 show the presence of ferromagnetic interaction between the radical cations with copper(II, in the temperature range of 20-300 K. The magnets 3 and 4 exhibit spontaneous magnetization at critical temperatures, Tc, of 23 K and 24 K, respectively.

  20. H2O Paradox and its Implications on H2O in Moon

    Science.gov (United States)

    Zhang, Youxue

    2017-04-01

    The concentration of H2O in the mantle of a planetary body plays a significant role in the viscosity and partial melting and hence the convection and evolution of the planetary body. Even though the composition of the primitive terrestrial mantle (PTM) is thought to be well known [1-2], the concentration of H2O in PTM remains paradoxial because different methods of estimation give different results [3]: Using H2O/Ce ratio in MORB and OIB and Ce concentration in PTM, the H2O concentration in PTM would be (300÷×1.5) ppm; using mass balance by adding surface water to the mantle [3-4], H2O concentration in PTM would be (900÷×1.3) ppm [2-3]. The inconsistency based on these two seemingly reliable methods is referred to as the H2O paradox [3]. For Moon, H2O contents in the primitive lunar mantle (PLM) estimated from H2O in plagioclase in lunar anorthosite and that from H2O/Ce ratio in melt inclusions are roughly consistent at ˜110 ppm [5-6] even though there is still debate about the volatile depletion trend [7]. One possible solution to the H2O paradox in PTM is to assume that early Earth experienced whole mantle degassing, which lowered the H2O/Ce ratio in the whole mantle but without depleting Ce in the mantle. The second possible solution is that some deep Earth reservoirs with high H2O/Ce ratios have not been sampled by MORB and OIB. Candidates include the transition zone [8] and the D" layer. The third possible solution is that ocean water only partially originated from mantle degassing, but partially from extraterrestrial sources such as comets [9-10]. At present, there is not enough information to determine which scenario is the answer to the H2O paradox. On the other hand, each scenario would have its own implications to H2O in PLM. If the first scenario applies to Moon, because degassed H2O or H2 would have escaped from the lunar surface, the very early lunar mantle could have much higher H2O [11] than that obtained using the H2O/Ce ratio method. The

  1. Preparation of Fe(II)-H2O2-impregnated granular activated carbon at different temperatures for arsenate removal from water%Fe(Ⅱ)-H2O2不同温度浸润改性活性炭吸附去除水中砷(V)

    Institute of Scientific and Technical Information of China (English)

    唐敏康; 陈苹; 许建红; 高乃云; 肖爱红

    2014-01-01

    Fe(Ⅱ)-H2O2不同温度浸润改性活性炭是采用FeSO4·7H2O添加H2O2在温度100℃下纯浸润24 h(Fe(Ⅱ)-24 h)和高温蒸发15 min(Fe(Ⅱ)-15 min)制备.对2类材料进行SEM表征并对其吸附1.1 mg/L砷(V)的性能进行比较.SEM显示Fe(Ⅱ)(0.485%)-24 h(0.485%为Fe(Ⅱ)-24 h的铁含量,下同)表面覆盖厚的棒状纳米羟基铁,Fe(Ⅱ)(1.35%)-15 min表面覆盖薄而烧结扭曲羟基铁;高温蒸发15 min有利于铁负载;Fe(Ⅱ)-24 h(108~142 mg/gFe)对砷(V)吸附的铁效率是Fe(Ⅱ)-15 min(57~63 mg/gFe)的2倍;Fe(Ⅱ)(0.485%)-24 h在2H2O2 incipient wetness impregnation at different temperatures are prepared by FeSO4·7H2O and hydrogen peroxide (H2O2) via the incipient wetness for 24 h at 100℃(Fe(Ⅱ)-24 h ) and the high temperature evaporation for 15 min (Fe(Ⅱ)-15 min).Fe(Ⅱ)-24 h and Fe(Ⅱ)-15 min are characterized by SEM and are compared for the adsorption behavior of the arsenate (1.1 mg/L).The SEM has shown that nano-iron hydroxides are formed on the surface of Fe (Ⅱ)(0.485 %)-24 h (0.485 % is the iron content of Fe (Ⅱ)-24 h,the same below) and that sintering distorted hydroxides are formed on the surface of Fe (Ⅱ)(1.35 %)-15 min.The high temperature evaporation for 15 min is favorable for iron to load on GAC. The iron use efficiency of Fe(Ⅱ)-24 h(108~142 mg/gFe) is two fold of that of Fe(Ⅱ)-15 min(57~63 mg/gFe).The arsenate equilibrium adsorption capacity of Fe(Ⅱ) (0.485 %)-24 h is better than the Fe(Ⅱ)(1.35 %)-15 min at pH 2~3.5 or 9~12,at the same time,the soluble iron at any particular pH released from

  2. Supramolecular network formed through O-H$\\cdots$O and - stacking interactions: Hydrothermal syntheses and crystal structures of M(H2O)6](optp)2 (M = Mg, Ni, Zn, and optp = 1-oxopyridinium-2-thiopropionate)

    Indian Academy of Sciences (India)

    Murugan Indrani; Ramasamy Ramasubramanian; Frank R Fronczek; Dario Braga; N Y Vasanthacharya; Sudalaiandi Kumaresan

    2009-07-01

    A novel class of complexes of the type [M(H2O)6](optp)2 (where M = Mg, Ni, Zn, and optp = 1-oxopyridinium-2-thiopropionate) were prepared hydrothermally from metal acetates and 1-oxopyridinium-2-thiopropionic acid (Hoptp), and structurally characterized by X-ray diffraction. Complexes [Mg(H2O)6](optp)2 (1), [Ni(H2O)6](optp)2 (2) and [Zn(H2O)6](optp)2 (3) have isomorphic structures, consisting of one [M(H2O)6]2+ cation and two anions of Hoptp, which are linked through hydrogen bonding to form extended networks. In each case, the metal cation sits on a crystallographic centre of inversion and binds to six water molecules. The organic anions form a one-dimensional chain with the hexaaquametal(II) moieties via hydrogen bonds.

  3. Proton ordering dynamics of H2O ice

    CERN Document Server

    Yen, Fei

    2015-01-01

    From high precision measurements of the complex dielectric constant of H2O ice, we identify the critical temperatures of the phase transition into and out of ice XI from ice Ih to occur at T_Ih-IX=58.9 K and T_IX-Ih=73.4 K. For D2O, T_Ih-IX=63.7 K and T_IX-Ih=78.2 K. A triple point is identified to exist at 0.07 GPa and 73.4 K for H2O and 0.08 GPa and 78.2 K for D2O where ices Ih, II and XI coexist. A first order phase transition with kinetic broadening associated to proton ordering dynamics is identified at 100 K.

  4. Enhanced catalytic four-electron dioxygen (O2) and two-electron hydrogen peroxide (H2O2) reduction with a copper(II) complex possessing a pendant ligand pivalamido group.

    Science.gov (United States)

    Kakuda, Saya; Peterson, Ryan L; Ohkubo, Kei; Karlin, Kenneth D; Fukuzumi, Shunichi

    2013-05-01

    A copper complex, [(PV-tmpa)Cu(II)](ClO4)2 (1) [PV-tmpa = bis(pyrid-2-ylmethyl){[6-(pivalamido)pyrid-2-yl]methyl}amine], acts as a more efficient catalyst for the four-electron reduction of O2 by decamethylferrocene (Fc*) in the presence of trifluoroacetic acid (CF3COOH) in acetone as compared with the corresponding copper complex without a pivalamido group, [(tmpa)Cu(II)](ClO4)2 (2) (tmpa = tris(2-pyridylmethyl)amine). The rate constant (k(obs)) of formation of decamethylferrocenium ion (Fc*(+)) in the catalytic four-electron reduction of O2 by Fc* in the presence of a large excess CF3COOH and O2 obeyed first-order kinetics. The k(obs) value was proportional to the concentration of catalyst 1 or 2, whereas the k(obs) value remained constant irrespective of the concentration of CF3COOH or O2. This indicates that electron transfer from Fc* to 1 or 2 is the rate-determining step in the catalytic cycle of the four-electron reduction of O2 by Fc* in the presence of CF3COOH. The second-order catalytic rate constant (k(cat)) for 1 is 4 times larger than the corresponding value determined for 2. With the pivalamido group in 1 compared to 2, the Cu(II)/Cu(I) potentials are -0.23 and -0.05 V vs SCE, respectively. However, during catalytic turnover, the CF3COO(-) anion present readily binds to 2 shifting the resulting complex's redox potential to -0.35 V. The pivalamido group in 1 is found to inhibit anion binding. The overall effect is to make 1 easier to reduce (relative to 2) during catalysis, accounting for the relative k(cat) values observed. 1 is also an excellent catalyst for the two-electron two-proton reduction of H2O2 to water and is also more efficient than is 2. For both complexes, reaction rates are greater than for the overall four-electron O2-reduction to water, an important asset in the design of catalysts for the latter.

  5. H2O and CO coadsorption on Co (0001): The effect of intermolecular hydrogen bond

    Science.gov (United States)

    Jiawei, Wu; Chen, Jun; Guo, Qing; Su, Hai-Yan; Dai, Dongxu; Yang, Xueming

    2017-09-01

    The co-adsorption of CO and H2O on a Co(0001) surface at 100 K has been systematically studied using temperature programmed desorption (TPD) and density functional theory (DFT) calculations. While the TPD spectra of CO is almost not affected by the presence of H2O, the stabilization of H2O by co-adsorbed CO is found for the first time in a large coverage range (0.15 ML H2O is gradually separated into three peaks at 0.6 ML coverage. Those at lower and higher temperatures may be attributed to the repulsive interaction between H2O molecules and the attractive interaction between H2O and CO molecules, respectively. With increasing the coverage of predosed CO, not only the position of the high temperature peak shifts toward higher temperature (by about 15 K), but the intensity is greatly strengthened until a maximum is achieved when θCO = 0.36 ML. DFT calculations suggest that the attractive interaction between H2O and CO on Co(0001) originates from the formation of intermolecular hydrogen bonds. This work not only provides insights into water gas shift reactions with H2O and CO as reactants, but opens new avenues for a volume of catalytic process of technological importance.

  6. Hydrothermal Synthesis, Crystal Structure and Thermal Analyses of Pyrazine-2,3-dicarboxylic Acid Bridged Co(II) Coordination Polymer of 2∞[Co(phen) (μ-L)3/3]·H2O (H2L = Pyrazine-2,3-dicarboxylic Acid)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bi-Song

    2005-01-01

    A novel pyrazine-2,3-dicarboxylic acid bridged Co(II) phen complex2∞[Co- (phen)(μ-L)3/3]·H2O (H2L = pyrazine-2,3-dicarboxylic acid) has been hydrothermally synthesized, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group P21/n with a = 11.480(2), b = 11.885(2), c = 12.939(3) (A), β = 110.55(3)°, V = 1653.1(6) (A)3, Mr = 423.25, Dc = 0.425 g/cm3, Z = 4, R = 0.0361 and wR = 0.1011. The title complex consists of 2D 2∞ [Co(phen)(μ-L)3/3] layers and crystal water molecules. Each Co atom is octahedrally coordinated by three N atoms and three O atoms to form 2D 2∞[Co(phen)(μ-L)3/3] polymeric layers. Furthermore, such 2D layers are stacked into 3D supramolecular frameworks via Van der Waals' intermolecular forces, strong and weak hydrogen-bond interactions. The coordination phen and crystal water molecules are resided into cavities of the frameworks.

  7. Kinetics of HO2 + HO2 -> H2O2 + O2: Implications for Stratospheric H2O2

    Science.gov (United States)

    Christensen, L. E.; Okumura, M.; Sander, S. P.; Salawitch, R. J.; Toon, G. C.; Sen, B.; Blavier, J.-F.; Jucks, K. W.

    2002-05-01

    The reaction HO2 + HO2 -> H2O2 + O2refid="df01" type="formula">(1) has been studied at 100 Torr and 222 K to 295 K. Experiments employing photolysis of Cl2/CH3OH/O2/N2 and F2/H2/O2/N2 gas mixtures to produce HO2 confirmed that methanol enhanced the observed reaction rate. At 100 Torr, zero methanol, k1 = (8.8 +/- 0.9) 10-13 × exp[(210 +/- 26)/T] cm3 molecule-1 s-1 (2σ uncertainties), which agrees with current recommendations at 295 K but is nearly 2 times slower at 231 K. The general expression for k1, which includes the dependence on bath gas density, is k1 = (1.5 +/- 0.2) × 10-12 × exp[(19 +/- 31)/T] + 1.7 × 10-33 × [M] × exp[1000/T], where the second term is taken from the JPL00-3 recommendation. The revised rate largely accounts for a discrepancy between modeled and measured [H2O2] in the lower to middle stratosphere.

  8. Copernicus observational searches for OH and H2O in diffuse clouds

    Science.gov (United States)

    Smith, W. H.; Snow, T. P., Jr.

    1983-01-01

    An intensive search for OH and H2O in the directions of sigma Sco, alpha Cam, and micron Per was undertaken with the Copernicus satellite. Multiple scans were carried out over the wavelength region for the expected absorption features due to the OH D-X and H2O C-X transitions. The feature due to OH was detected marginally towards sigma Sco, and only an upper limit can be given towards alpha Cam. H2O was not detected in any of the stars at the signal level accumulated. The OH abundance towards sigma Sco and the respective lower limits for the OH/H2O ratios are discussed with regard to the extant models for the steady state abundances of OH and H2O, and shown not to be inconsistent with ion-molecule schemes.

  9. Preparation, Characterization and Properties of Ag(Ⅰ) Coordination Polymer [Ag2(bpp) 2(H2O)]·pydc·7H2O

    Institute of Scientific and Technical Information of China (English)

    GUO, Chunyan; WEN, Guilin; WANG, Yaoyu; FU, Aiyun; LERMONTOVA, ElmiraKh; SHI, Qizhen

    2009-01-01

    A new coordination polymer, [Ag2(bpp)2(H2O)]·pydc·7H2O (1), derived from the ligand pyridine-3,5- dicarboxylic acid (H2pydc), has been obtained through a hydrothermal technique [bpp=1,3-bis(4-pyridyl)propane]. Its single crystal structure has been determined by X-ray crystallography. A 2D sheet containing (H2O)12 water units was formed. Interestingly, each pydc dianion bridged two (H2O)12 units and two free water molecules in the con- struction of 2D hydrogen-bonding sheets. Additionally, fluorescent properties, TG analysis, and PXRD for complex 1 were also measured and discussed.

  10. Vibrational investigations of CO2-H2O, CO2-(H2O)2, and (CO2)2-H2O complexes isolated in solid neon

    Science.gov (United States)

    Soulard, P.; Tremblay, B.

    2015-12-01

    The van der Waals complex of H2O with CO2 has attracted considerable theoretical interest as a typical example of a weak binding complex with a dissociation energy less than 3 kcal/mol. Up to now, experimental vibrational data are sparse. We have studied by FTIR the complexes involving CO2 and water molecules in solid neon. Many new absorption bands close to the well known monomers fundamentals give evidence for at least three (CO2)n-(H2O)m complexes, noted n:m. Concentration effects combined with a detailed vibrational analysis allow for the identification of sixteen, twelve, and five transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared spectral region allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra + intermolecular transitions, and anharmonic coupling constants have been derived. Our results demonstrate the high sensibility of the solid neon isolation to investigate the hydrogen-bonded complexes in contrast with the gas phase experiments for which two quanta transitions cannot be easily observed.

  11. Vibrational investigations of CO2-H2O, CO2-(H2O)2, and (CO2)2-H2O complexes isolated in solid neon.

    Science.gov (United States)

    Soulard, P; Tremblay, B

    2015-12-14

    The van der Waals complex of H2O with CO2 has attracted considerable theoretical interest as a typical example of a weak binding complex with a dissociation energy less than 3 kcal/mol. Up to now, experimental vibrational data are sparse. We have studied by FTIR the complexes involving CO2 and water molecules in solid neon. Many new absorption bands close to the well known monomers fundamentals give evidence for at least three (CO2)n-(H2O)m complexes, noted n:m. Concentration effects combined with a detailed vibrational analysis allow for the identification of sixteen, twelve, and five transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared spectral region allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra + intermolecular transitions, and anharmonic coupling constants have been derived. Our results demonstrate the high sensibility of the solid neon isolation to investigate the hydrogen-bonded complexes in contrast with the gas phase experiments for which two quanta transitions cannot be easily observed.

  12. Synthesis, characterization, single crystal X-ray structure, EPR and theoretical studies of a new hybrid inorganic-organic compound [Cu(Hdien)2(H2O)2](pnb)4·4H2O and its structural comparison with related [Cu(en)2(H2O)2](pnb)2

    Science.gov (United States)

    Kumar, Santosh; Sharma, Raj Pal; Venugopalan, Paloth; Witwicki, Maciej; Ferretti, Valeria

    2016-11-01

    A new hybrid inorganic-organic compound [Cu(Hdien)2(H2O)2](pnb)4·4H2O (1) (where pnb = p-nitrobenzoate), in which the tridentate ligand diethylenetriamine (dien) shows an unusual coordination behavior acting as a bidentate ligand when present in its monoprotonated form (Hdien+) has been synthesized by the reaction of copper(II) p-nitrobenzoate and slight excess of dien in methanol-water mixture (4:1v/v). Re-crystallization of the violet precipitated product from hot water gave single crystals suitable for X-ray diffraction studies. The newly synthesized compound 1 has been characterized by spectroscopic techniques (UV-Vis, FT-IR, EPR), and theoretical methods (DFT and MRCI/SORCI). Single crystal X-ray structure determination revealed the existence of the cationic species [Cu(Hdien)2(H2O)2]4+, four p-nitrobenzoate as counter anions and four water molecules are present as solvent of crystallization. Packing analyses of title compound as well as of the structurally similar [Cu(en)2(H2O)2](pnb)2,2 has shown similarities in the crystalline architecture that both hybrid inorganic-organic compounds is stabilized by various non-covalent interactions such as N-H⋯O, C-H⋯O, O-H⋯O etc.

  13. Frank-Condon factors for H2O(+) molecular bands

    Science.gov (United States)

    Shefov, N. N.

    1983-11-01

    The Frank-Condon factors q sub (v' v'') are calculated for the spectra of the H2O(+) molecule by the method of Volkenstein et al. (1972). The results are presented in a table for values of v' from 5 to 17 and of v'' from zero to 4, indicating which bands have been observed either in the laboratory or in comets. It is shown that the photon scattering coefficient of Chamberlain (1978) can be calculated using these data for the (8,0) band; values of about 0.060 for the earth and about 0.17 for Halley's comet (at its 1986 perihelion) are determined.

  14. Production of superoxide/H2O2 by dihydroorotate dehydrogenase in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Hey-Mogensen, Martin; Goncalves, Renata L S; Orr, Adam L; Brand, Martin D

    2014-07-01

    Dehydrogenases that use ubiquinone as an electron acceptor, including complex I of the respiratory chain, complex II, and glycerol-3-phosphate dehydrogenase, are known to be direct generators of superoxide and/or H2O2. Dihydroorotate dehydrogenase oxidizes dihydroorotate to orotate and reduces ubiquinone to ubiquinol during pyrimidine metabolism, but it is unclear whether it produces superoxide and/or H2O2 directly or does so only indirectly from other sites in the electron transport chain. Using mitochondria isolated from rat skeletal muscle we establish that dihydroorotate oxidation leads to superoxide/H2O2 production at a fairly high rate of about 300pmol H2O2·min(-1)·mg protein(-1) when oxidation of ubiquinol is prevented and complex II is uninhibited. This H2O2 production is abolished by brequinar or leflunomide, known inhibitors of dihydroorotate dehydrogenase. Eighty percent of this rate is indirect, originating from site IIF of complex II, because it can be prevented by malonate or atpenin A5, inhibitors of complex II. In the presence of inhibitors of all known sites of superoxide/H2O2 production (rotenone to inhibit sites in complex I (site IQ and, indirectly, site IF), myxothiazol to inhibit site IIIQo in complex III, and malonate plus atpenin A5 to inhibit site IIF in complex II), dihydroorotate dehydrogenase generates superoxide/H2O2, at a small but significant rate (23pmol H2O2·min(-1)·mg protein(-1)), from the ubiquinone-binding site. We conclude that dihydroorotate dehydrogenase can generate superoxide and/or H2O2 directly at low rates and is also capable of indirect production at higher rates from other sites through its ability to reduce the ubiquinone pool.

  15. Distorted Tetrahedral CoII in K5H[CoW12O40]·xH2O Probed by 2p3d Resonant Inelastic X-ray Scattering

    NARCIS (Netherlands)

    Liu, LIU BY; Wang, Ru Pan; Glass, Elliot N.; Hill, Craig L.; Cuk, Tanja; Okamoto, Jun; Huang, Di Jing; Van Schooneveld, Matti M.; De Groot, Frank M F

    2016-01-01

    The Co 2p3/2 X-ray absorption spectroscopy and high-energy-resolution (∼0.09 eV fwhm) 2p3d resonant inelastic X-ray scattering (RIXS) spectra of the single-cobalt-centered polyoxometalate K5H[CoW12O40]·xH2O were measured. The low-energy dd transition features at 0.55 eV, unmeasurable with

  16. Copper(II)-malonato coordination frameworks with ethanolammonium cations. Synthesis, spectral, thermal and structural characterization of trans-[Cu(mal) 2(meaH) 2] and {(deaH) 2[Cu(μ-mal) 2]·H 2O} ∞ (meaH=monoethanolammonium, deaH=diethanolammonium and mal=malonate)

    Science.gov (United States)

    Yilmaz, Veysel T.; Senel, Evrim; Kazak, Canan

    2004-08-01

    Two isomorphous malonato-copper(II) complexes, [Cu(mal) 2(meaH) 2] and {(deaH) 2[Cu(μ-mal) 2]·H 2O} ∞ (meaH=monoethanolammonium, deaH=diethanolammonium and mal=malonate), have been prepared and characterized by elemental analyses, IR, UV-vis, magnetic measurements and single crystal X-ray diffraction. The mononuclear complex crystallizes in the monoclinic space group P2 1/ n, with a=8.6630(8) Å, b=7.5122(5) Å, c=11.4390(10) Å, β=95.530(7) and Z=2. The polymeric malonato-bridged copper(II) complex crystallizes in the monoclinic space group P2 1/ c, with a=26.5169(14) Å, b=8.2544(5) Å, c=9.5243(5) Å, β=96.256(4) and Z=4. The monomeric complex consists of individual units in which copper(II) sits on the inversion center and is octahedrally coordinated by two bidentate mal and two monodendate meaH ligands. The structural units are joined into the framework by the system of hydrogen bonds. The polymeric complex composed of two-dimensional chains containing the mal bridged [Cu(mal) 2] 2- ions and each mal ligand simultaneously exhibits chelating bidentate (at one copper atom) and bridging (at the adjacent copper atom) coordination modes. The intrachain Cu1⋯Cu2 separation is 6.302(4) Å. The deaH cations are not coordinated to copper(II) and occupy the voids of the frame work, together with the lattice water molecules. The IR spectra and thermal decompositions of both complexes are described in detail.

  17. Synthesis, characterization and antimicrobial activity of novel platinum(IV) and palladium(II) complexes with meso-1,2-diphenyl-ethylenediamine-N,N‧-di-3-propanoic acid - Crystal structure of H2-1,2-dpheddp·2HCl·H2O

    Science.gov (United States)

    Radić, Gordana P.; Glođović, Verica V.; Ratković, Zoran R.; Novaković, Slađana B.; Garcia-Granda, Santiago; Roces, Laura; Menéndez-Taboada, Laura; Radojević, Ivana D.; Stefanović, Olgica D.; Čomić, Ljiljana R.; Trifunović, Srećko R.

    2012-12-01

    In the reaction of meso-1,2-diphenyl-ethylenediamine (1,2-dphen) with neutralized 3-chlor-propanoic acid, the new linear tetradentate edda-like ligand (edda = ethylenediamine-N,N'-diacetic ion) meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoic acid dihydrochloride monohydrate (H2-1,2-dpheddp·2HCl·H2O) was prepared. The corresponding platinum(IV) complex, s-cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-platinum(IV) ([PtCl2(1,2-dpheddp)]) was synthesized by heating potassium-hexachloridoplatinate(IV) and H2-1,2-dpheddp·2HCl·H2O on steam bath for 12 h with neutralization by means of lithium-hydroxide. The palladium(II) complex, cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-palladium(II) ([PdCl2(1,2-dpheddp)]) was obtained in the similar way using potassium-tetrachloridopalladate(II), H2-1,2-dpheddp·2HCl·H2O and lithium-hydroxide. The compounds were characterized by elemental analysis and infrared spectroscopy. The spectroscopically predicted structure of the synthesized tetradentate ligand was confirmed by X-ray analysis of the H2-1,2-dpheddp·2HCl·H2O. Antimicrobial activity of the ligand and corresponding palladium(II) and platinum(IV) complexes is investigated against 25 species of microorganisms. Testing is preformed by microdilution method and minimum inhibitory concentrations (MIC) and minimum microbicidal concentration (MMC) have been determined. The difference between antimicrobial activity of the ligand and corresponding platinum(IV) and palladium(II) complex is noticed and, in general, palladium(II) complex was the most active.

  18. UV and IR Spectroscopy of Cold H2O(+)-Benzo-Crown Ether Complexes.

    Science.gov (United States)

    Inokuchi, Yoshiya; Ebata, Takayuki; Rizzo, Thomas R

    2015-11-12

    The H2O(+) radical ion, produced in an electrospray ion source via charge transfer from Eu(3+), is encapsulated in benzo-15-crown-5 (B15C5) or benzo-18-crown-6 (B18C6). We measure UV photodissociation (UVPD) spectra of the (H2O·B15C5)(+) and (H2O·B18C6)(+) complexes in a cold, 22-pole ion trap. These complexes show sharp vibronic bands in the 35 700-37 600 cm(-1) region, similar to the case of neutral B15C5 or B18C6. These results indicate that the positive charge in the complexes is localized on H2O, giving the forms H2O(+)·B15C5 and H2O(+)·B18C6, in spite of the fact that the ionization energy of B15C5 and B18C6 is lower than that of H2O. The formation of the H2O(+) complexes and the suppression of the H3O(+) production through the reaction of H2O(+) and H2O can be attributed to the encapsulation of hydrated Eu(3+) clusters by B15C5 and B18C6. On the contrary, the main fragment ions subsequent to the UV excitation of these complexes are B15C5(+) and B18C6(+) radical ions; the charge transfer occurs from H2O(+) to B15C5 and B18C6 after the UV excitation. The position of the band origin for the H2O(+)·B18C6 complex (36323 cm(-1)) is almost the same as that for Rb(+)·B18C6 (36315 cm(-1)); the strength of the intermolecular interaction of H2O(+) with B18C6 is similar to that of Rb(+). The spectral features of the H2O(+)·B15C5 complex also resemble those of the Rb(+)·B15C5 ion. We measure IR-UV spectra of these complexes in the CH and OH stretching region. Four conformers are found for the H2O(+)·B15C5 complex, but there is one dominant form for the H2O(+)·B18C6 ion. This study demonstrates the production of radical ions by charge transfer from multivalent metal ions, their encapsulation by host molecules, and separate detection of their conformers by cold UV spectroscopy in the gas phase.

  19. Assembly of Carbohydrates on a Nickel(II) Center by Utilizing N-Glycosidic Bond Formation with Tris(2-aminoethyl)amine (tren). Syntheses and Characterization of [Ni{N-(aldosyl)-tren}(H(2)O)](2+), [Ni{N,N'-bis(aldosyl)-tren}](2+) and [Ni{N,N',N"-tris(aldosyl)-tren}](2+).

    Science.gov (United States)

    Tanase, Tomoaki; Doi, Mayumi; Nouchi, Reiko; Kato, Masako; Sato, Yutaka; Ishida, Katsuaki; Kobayashi, Kimiko; Sakurai, Tosio; Yamamoto, Yasuhiro; Yano, Shigenobu

    1996-08-14

    Reactions of [Ni(tren)(H(2)O)(2)]X(2) (tren = tris(2-aminoethyl)amine; X = Cl (1a), Br (1b); X(2) = SO(4) (1c)) with mannose-type aldoses, having a 2,3-cis configuration (D-mannose and L-rhamnose), afforded {bis(N-aldosyl-2-aminoethyl)(2-aminoethyl)amine}nickel(II) complexes, [Ni(N,N'-(aldosyl)(2)-tren)]X(2) (aldosyl = D-mannosyl, X = Cl (2a), Br (2b), X(2) = SO(4) (2c); aldosyl = L-rhamnosyl, X(2) = SO(4) (3c)). The structure of 1c was confirmed by X-ray crystallography to be a mononuclear [Ni(II)N(4)O(2)] complex with the tren acting as a tetradentate ligand (1c.2H(2)O: orthorhombic, Pbca, a = 15.988(2) Å, b = 18.826(4) Å, c = 10.359(4) Å, V = 3118 Å(3), Z = 8, R = 0.047, and R(w) = 0.042). Complexes 2a,c and 3c were characterized by X-ray analyses to have a mononuclear octahedral Ni(II) structure ligated by a hexadentate N-glycoside ligand, bis(N-aldosyl-2-aminoethyl)(2-aminoethyl)amine (2a.CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 16.005(3) Å, b = 20.095(4) Å, c = 8.361(1) Å, V = 2689 Å(3), Z = 4, R = 0.040, and R(w) = 0.027. 2c.3CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 14.93(2) Å, b = 21.823(8) Å, c = 9.746(2) Å, V = 3176 Å(3), Z = 4, R = 0.075, and R(w) = 0.080. 3c.3CH(3)OH: orthorhombic, P2(1)2(1)2(1), a = 14.560(4) Å, b = 21.694(5) Å, c = 9.786(2) Å, V = 3091 Å(3), Z = 4, R = 0.072, and R(w) = 0.079). The sugar part of the complex involves novel intramolecular sugar-sugar hydrogen bondings around the metal center. The similar reaction with D-glucose, D-glucosamine, and D-galactosamine, having a 2,3-trans configuration, resulted in the formation of a mono(sugar) complex, [Ni(N-(aldosyl)-tren)(H(2)O)(2)]Cl(2) (aldosyl = D-glucosyl (4b), 2-amino-2-deoxy-D-glucosyl (5a), and 2-amino-2-deoxy-D-galactosyl (5b)), instead of a bis(sugar) complex. The hydrogen bondings between the sugar moieties as observed in 2 and 3 should be responsible for the assembly of two sugar molecules on the metal center. Reactions of tris(N-aldosyl-2-aminoethyl

  20. Nuclear Magnetic Resonance as a Probe of Meso-timescale Dynamics: Ion and H2O Behavior at Mineral-H2O Interfaces

    Science.gov (United States)

    Bowers, G. M.; Kirkpatrick, R. J.; Singer, J. W.

    2012-12-01

    One of the important meso-scales in geochemistry is the meso-timescale that is characteristic of processes too slow to probe with light spectroscopy but too fast to probe macroscopically. Nuclear magnetic resonance (NMR) spectroscopy is one of the only analytical methods with dynamic sensitivity to motions with correlation times on the 10-9 to 1 s timescales and is thus a uniquely powerful probe of meso-timescale dynamic behavior. Here, we describe the results of several studies exploring the meso-timescale motion of ions and H2O at the mineral-H2O interface of hectorite, a smectite clay mineral.1-3 2H, 23Na, 39K and 43Ca NMR results show that H2O molecules associated with the interface undergo anisotropic reorientation due to proximity to the surface and surface-associated cations. This motion can be described by rotational diffusion of the H2O molecule about its C2 symmetry axis at GHz frequencies combined with hopping of the H2O molecule about the normal to the smectite surface at ~>200 kHz. This model describes well the observed 2H NMR spectra of Na+, K+, and Ca2+ hectorites over a range temperatures between -80°C and 50°C, with the specific range dependent only on the total system H2O content. At temperatures above -20°C, systems with excess H2O with respect to a two-layer hydrate (low-H2O pastes through dilute aqueous suspensions) experience additional dynamic averaging due to H2O exchange between cation hydration shells, surface-sorbed species, and bulk inter-particle water. The extent of 2H averaging due to this exchange mechanism is strongly affected by the total H2O content in the system, the identity of the charge balancing cation, and the temperature. The dynamic averaging mechanisms affecting the cationic NMR resonances in these systems become dominated by diffusional processes at progressively lower temperatures as the hydration energy of the cation increases. These interfacial cation dynamics and binding sites are strongly affected by surface

  1. H2O Nucleation Around Noble Metal Cations

    Science.gov (United States)

    Calaminici, Patrizia; Oropeza Alfaro, Pavel; Juarez Flores, Martin; Köster, Andreas; Beltran, Marcela; Ulises Reveles, J.; Khanna, Shiv N.

    2008-03-01

    First principle electronic structure calculations have been carried out to investigate the ground state geometry, electronic structure and binding energy of noble metal cations (H2O)n^+ clusters containing up to 10 H2O molecules. The calculations are performed with the density functional theory code deMon2k [1]. Due to the very flat potential energy surface of these systems special care to the numerical stability of energy and gradient calculation must be taken.Comparison of the results obtained with Cu^+, Ag^+ and Au^+ will be shown. This investigation provides insight into the structural arrangement of the water molecules around these metals and a microscopic understanding of the observed incremental binding energy in the case of the gold cation based on collision induced dissociation experiments. [1] A.M. Köster, P. Calaminici, M.E. Casida, R. Flores-Moreno, G. Geudtner, A. Goursot, T. Heine, A. Ipatov, F. Janetzko, J. Martin del Campo, S. Patchkovski, J.U. Reveles, A. Vela and D.R. Salahub, deMon2k, The deMon Developers, Cinvestav, 2006

  2. Kinetics of the atrazine degradation process using H2O2-UVC.

    Science.gov (United States)

    Sarmento, Sandra M; Miranda, José T G

    2014-01-01

    This work is concerned with the intrinsic reaction kinetic of the degradation of atrazine (ATZ) using H2O2-UVC. Experimental runs were carried out in annular photoreactor. The initial concentration of ATZ was 2.2 × 10(-2) mol m(-3) while the H2O2-ATZ molar ratio range was 0-578 mol H2O2 mol(-1) ATZ. The ATZ molecules are decomposed by means of free-radical attack (95.2%) and direct photolysis (4.8%). There is an optimal H2O2/ATZ molar ratio (ROP = 347 H2O2 mol(-1) ATZ) which maximizes the initial degradation rate and conversion at 300 s at 83% and 77%, respectively. The process is economically feasible as the values of the energy requirement, energy and H2O2 costs at ROP are 0.14 KWh m(-3) order(-1), US$0.02 kWh(-1) m(-3) and US$1.0 m(-3), respectively. The kinetic model proposed is based on Lea's reaction scheme for the H2O2 direct photolysis, the hypothesis that unknown ATZ sub-products that absorb UVC radiation are generated, and the local volumetric rate of photon absorption. The radiation transport equation was solved and the linear spherical source emission model was used to represent the lamp emission. Intrinsic reaction kinetic parameters were estimated and the model was validated. The model predicted the data in a range of 90 to 98%.

  3. Copper(II) ion catalytic oxidation of o-phenylenediamine and characterization, X-ray crystal structure and solution studies of the final product [DAPH][H3O][Cu(dipic)2]·3H2O

    Science.gov (United States)

    Ghasemi, Khaled; Rezvani, Ali Reza; Shokrollahi, Ardeshir; Abdul Razak, Ibrahim; Refahi, Masoud; Moghimi, Abolghasem; Rosli, Mohd Mustaqim

    2015-09-01

    The complex [DAPH][H3O][Cu(dipic)2]·3H2O, (1) (dipicH2 = 2,6-pyridinedicarboxylic acid and DAP = 2,3-diaminophenazine) was prepared from the reaction of Cu(NO3)2·2H2O with mixture of o-phenylenediamine (OPD) and 2,6-pyridinedicarboxylic acid in water. The complex was characterized by FTIR, elemental analysis, UV-Vis and the single-crystal X-ray diffraction. The crystal system is monoclinic with the space group P21/c. This complex is stabilized in the solid state by an extensive network of hydrogen bonds between crystallized water, anionic and cationic fragments, which form a three-dimensional network. Furthermore, hydrogen bonds, π⋯π and Csbnd O⋯π stacking interactions seem to be effective in stabilizing the crystal structures. The protonation constants of dipic (L) and DAP (Q), the equilibrium constants for the dipic-DAP proton transfer system and the stoichiometry and stability constants of binary complexes including each of ligands (dipic, DAP) in presence Cu2+ ion, ternary complexes including, both of ligands (dipic-DAP) in presence of metal ion were calculated in aqueous solutions by potentiometric pH titration method using the Hyperquad2008 program. The stoichiometry of the most complexes species in solution was found to be very similar to the solid-state of cited metal ion complex.

  4. H2O2 space shuttle APU

    Science.gov (United States)

    1975-01-01

    A cryogenic H2-O2 auxiliary power unit (APU) was developed and successfully demonstrated. It has potential application as a minimum weight alternate to the space shuttle baseline APU because of its (1) low specific propellant consumption and (2) heat sink capabilities that reduce the amount of expendable evaporants. A reference system was designed with the necessary heat exchangers, combustor, turbine-gearbox, valves, and electronic controls to provide 400 shp to two aircraft hydraulic pumps. Development testing was carried out first on the combustor and control valves. This was followed by development of the control subsystem including the controller, the hydrogen and oxygen control valves, the combustor, and a turbine simulator. The complete APU system was hot tested for 10 hr with ambient and cryogenic propellants. Demonstrated at 95 percent of design power was 2.25 lb/hp-hr. At 10 percent design power, specific propellant consumption was 4 lb/hp-hr with space simulated exhaust and 5.2 lb/hp-hr with ambient exhaust. A 10 percent specific propellant consumption improvement is possible with some seal modifications. It was demonstrated that APU power levels could be changed by several hundred horsepower in less than 100 msec without exceeding allowable turbine inlet temperatures or turbine speed.

  5. Synthesis and Crystal Structure of a Macrocycle [Cu(dadm)(mal)(H2O)]2·2H2O

    Institute of Scientific and Technical Information of China (English)

    林郑忠; 江飞龙; 陈莲; 洪茂椿

    2004-01-01

    The reaction of 4,4′-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]2(2H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2)A,Z= 106.75(3)o, V = 1693.5(6)A3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, λ(MoK() = 0.71073A, μ = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and Wr = 0.1244 for 3421 observed reflections with I > 2σ(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3A× 5.9A.

  6. Crystal structures of Na2SeO4·1.5H2O and Na2SeO4·10H2O

    Directory of Open Access Journals (Sweden)

    Matthias Weil

    2014-08-01

    Full Text Available The crystal structures of Na2SeO4·1.5H2O (sodium selenate sesquihydrate and Na2SeO4·10H2O (sodium selenate decahydrate are isotypic with those of Na2CrO4·1.5H2O and Na2XSeO4·10H2O (X = S, Cr, respectively. The asymmetric unit of the sesquihydrate contains two Na+ cations, one SeO4 tetrahedron and one and a half water molecules, the other half being generated by twofold rotation symmetry. The coordination polyhedra of the cations are a distorted monocapped octahedron and a square pyramid; these [NaOx] polyhedra are linked through common edges and corners into a three-dimensional framework structure, the voids of which are filled with the Se atoms of the SeO4 tetrahedra. The structure is consolidated by O—H...O hydrogen bonds between coordinating water molecules and framework O atoms. The asymmetric unit of the decahydrate consists of two Na+ cations, one SeO4 tetrahedron and ten water molecules. Both Na+ cations are octahedrally surrounded by water molecules and by edge-sharing condensed into zigzag chains extending parallel to [001]. The SeO4 tetrahedra and two uncoordinating water molecules are situated between the chains and are connected to the chains through an intricate network of medium-strength O—H...O hydrogen bonds.

  7. Linear trinuclear cobalt(II) single molecule magnet.

    Science.gov (United States)

    Zhang, Yuan-Zhu; Brown, Andrew J; Meng, Yin-Shan; Sun, Hao-Ling; Gao, Song

    2015-02-14

    The introduction of NaBPh(4) into a methanolic solution of CoCl(2)·(6)H(2)O and 2-[(pyridine-2-ylimine)-methyl]phenol (Hpymp) afforded {[Co(II)(3)(pymp)(4)(MeOH)(2)][BPh(4)](2)}·(2)MeOH (1) with a centro-symmetrically linear trinuclear structure. Magnetic analysis of 1 exhibited significant intracluster ferromagnetic exchange (2.4 cm(-1)) and slow relaxation of magnetization in both zero and non-zero static fields below 5 K, giving the first [Co(II)(3)] single molecule magnet with an effective energy barrier of 17.2(3) cm(-1) under a 500 Oe dc field.

  8. Adsorption, Diffusion, and Dissociation of H2O on Kaolinite (001): a Density Functional Study

    Institute of Scientific and Technical Information of China (English)

    HE Man-Chao; ZHAO Jian

    2012-01-01

    Density functional theory is used to investigate the adsorption,diffusion,and dissociation of H2O on kaolinite(001) surface.It is found that the preferred adsorption sites on the kaolinite(001) surface for H2O are the threefold hollow sites with the adsorption energies ranging from 1.06 to 1.15 eV.H2O does not adsorb on the six-fold hollow site of the aluminium(001) face of the third layer of kaolinite,implying that it is difficult for water molecules to penetrate the ideal kaolinite(001) surface.In addition,we calculate the energetic barriers for the diffusion of H2O between the most stable and next most stable adsorption sites,which range from 0.073 to 0.129eV.The results also show that H2O molecules are easy to diffuse on kaolinite(001) surface.Finally,our study indicates that no dissociation state exists for the H2O on kaolinite(001) surface.

  9. Hydrogen bonding and π-π stacking in nicotinamide/H2O mixtures

    Science.gov (United States)

    Zhai, Cuiping; Zhang, Ping; Peng, Peng; Hou, Bingbing; Li, Lina

    2017-09-01

    The interactions between nicotinamide (NA) and H2O were studied using UV-visible spectra (UV-Vis), cyclic voltammetry (CV), nuclear magnetic resonance (NMR), density functional theory (DFT) and atoms in molecules (AIM) analysis. According to the changes of the UV-Vis spectra and the oxidation and reduction potentials in cyclic voltammograms of NA in aqueous solution, it was found that hydrogen bonding occurred between NA and H2O molecules. Quantum chemistry calculations and AIM analysis further confirmed the existence of hydrogen bonding between H2O molecules and the amide group, the nitrogen atom, and hydrogen atoms on the pyridine ring of NA molecules. In addition, the NMR results demonstrated that the π-π stacking between NA pyridine rings could be formed at higher concentrations.

  10. Constraints on the H2O formation mechanism in the wind of carbon-rich AGB stars

    CERN Document Server

    Lombaert, R; Royer, P; de Koter, A; Cox, N L J; González-Alfonso, E; Neufeld, D; De Ridder, J; Agúndez, M; Blommaert, J A D L; Khouri, T; Groenewegen, M A T; Kerschbaum, F; Cernicharo, J; Vandenbussche, B; Waelkens, C

    2016-01-01

    Context. The recent detection of warm H$_2$O vapor emission from the outflows of carbon-rich asymptotic giant branch (AGB) stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H$_2$O vapor formation. In the first, periodic shocks passing through the medium immediately above the stellar surface lead to H$_2$O formation. In the second, penetration of ultraviolet interstellar radiation through a clumpy circumstellar medium leads to the formation of H$_2$O molecules in the intermediate wind. Aims. We aim to determine the properties of H$_2$O emission for a sample of 18 carbon-rich AGB stars and subsequently constrain which of the above mechanisms provides the most likely warm H$_2$O formation pathway. Methods, Results, and Conclusions. See paper.

  11. Descent Without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds

    Science.gov (United States)

    Loeffler, Mark Josiah; Hudson, Reggie Lester

    2015-01-01

    The strong oxidant H2O2 is known to exist in solid form on Europa and is suspected to exist on several other Solar System worlds at temperatures below 200 K. However, little is known of the thermal chemistry that H2O2 might induce under these conditions. Here, we report new laboratory results on the reactivity of solid H2O2 with eight different compounds in H2O-rich ices. Using infrared spectroscopy, we monitored compositional changes in ice mixtures during warming. The compounds CH4 (methane), C3H4 (propyne), CH3OH (methanol), and CH3CN (acetonitrile) were unaltered by the presence of H2O2 in ices, showing that exposure to either solid H2O2 or frozen H2O+H2O2 at cryogenic temperatures will not oxidize these organics, much less convert them to CO2. This contrasts strongly with the much greater reactivity of organics with H2O2 at higher temperatures, and particularly in the liquid and gas phases. Of the four inorganic compounds studied, CO, H2S, NH3, and SO2, only the last two reacted in ices containing H2O2, NH3 making NHþ 4 and SO2 making SO2 4 by H+ and e - transfer, respectively. An important astrobiological conclusion is that formation of surface H2O2 on Europa and that molecule's downward movement with H2O-ice do not necessarily mean that all organics encountered in icy subsurface regions will be destroyed by H2O2 oxidation.

  12. Syntheses and Structural Researches of Yb3+ Complexes with Nitrilotriacetic Acids--Nine-coordinate K3[Yb(nta)2(H2O)]·5H2O and Eight-coordinate Na3[Yb(nta)2]·6H2O Complexes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Yb3+ complexes with two nitrilotriacetic acid molecules were prepared and their compositions were determined as K3[Yb(nta)2(H2O)]*5H2O and Na3[Yb(nta)2]*6H2O by elemental analyses. Their structures were characterized by single-crystal X-ray diffraction analyses. In complex K3[Yb(nta)2(H2O)]*5H2O, the YbN2O7 part forms a nine-coordinate monocapped square antiprismatic structure. In complex Na3[Yb(nta)2]*6H2O, the YbN2O6 part forms an eight-coordinate square antiprismatic structure. It can be seen that the outer cations (K+ and Na+) greatly affect the coordination number and coordinate structure from these results.

  13. Stabilization and reactivity of a terminal phosphidounit on Pt(II). Synthesis and X-ray structure of cationic diphelylphosphine [Pt{C6H3(CH2NMe2)2-2,6}(PHPh2)][CF3SO3] and Diphenyl-phosphido Bridged Pt(II)-Pd(II) Complex [Pt{C6H3(CH2NMe2)2-2,6} (µ-PPh2) Pd(C6H4CH2NMe2-2)(H2O)][BF4] CH2Cl2

    NARCIS (Netherlands)

    Koten, G. van; Maassarani, F.; Davidson, M.F.; Wehman-Ooyevaar, ICM; Grove, D.M.; Koten, M.A. van; Smeets, W.J.J.; Spek, A.L.

    1995-01-01

    Reaction of diphenylphosphine with the complexes [Pt(NCN)(H{2}O)]X (NCN = C{6}H{3}(CH{2}NMe{2}){2}-2, 6; X = BF{4} (1a), OSO{2}CF{3} (1b)) leads to substitution of the H{2}O ligand to afford the ionic Pt(II) complexes [Pt(NCN)(PHPh{2})]X (X = BF{4} (2a), OSO{2}CF{3} (2b)). The X-ray structure of the

  14. Proximity-based Protein Thiol Oxidation by H2O2-scavenging Peroxidases*♦

    Science.gov (United States)

    Gutscher, Marcus; Sobotta, Mirko C.; Wabnitz, Guido H.; Ballikaya, Seda; Meyer, Andreas J.; Samstag, Yvonne; Dick, Tobias P.

    2009-01-01

    H2O2 acts as a signaling molecule by oxidizing critical thiol groups on redox-regulated target proteins. To explain the efficiency and selectivity of H2O2-based signaling, it has been proposed that oxidation of target proteins may be facilitated by H2O2-scavenging peroxidases. Recently, a peroxidase-based protein oxidation relay has been identified in yeast, namely the oxidation of the transcription factor Yap1 by the peroxidase Orp1. It has remained unclear whether the protein oxidase function of Orp1 is a singular adaptation or whether it may represent a more general principle. Here we show that Orp1 is in fact not restricted to oxidizing Yap1 but can also form a highly efficient redox relay with the oxidant target protein roGFP (redox-sensitive green fluorescent protein) in mammalian cells. Orp1 mediates near quantitative oxidation of roGFP2 by H2O2, and the Orp1-roGFP2 redox relay effectively converts physiological H2O2 signals into measurable fluorescent signals in living cells. Furthermore, the oxidant relay phenomenon is not restricted to Orp1 as the mammalian peroxidase Gpx4 also mediates oxidation of proximal roGFP2 in living cells. Together, these findings support the concept that certain peroxidases harbor an intrinsic and powerful capacity to act as H2O2-dependent protein thiol oxidases when they are recruited into proximity of oxidizable target proteins. PMID:19755417

  15. Proximity-based protein thiol oxidation by H2O2-scavenging peroxidases.

    Science.gov (United States)

    Gutscher, Marcus; Sobotta, Mirko C; Wabnitz, Guido H; Ballikaya, Seda; Meyer, Andreas J; Samstag, Yvonne; Dick, Tobias P

    2009-11-13

    H(2)O(2) acts as a signaling molecule by oxidizing critical thiol groups on redox-regulated target proteins. To explain the efficiency and selectivity of H(2)O(2)-based signaling, it has been proposed that oxidation of target proteins may be facilitated by H(2)O(2)-scavenging peroxidases. Recently, a peroxidase-based protein oxidation relay has been identified in yeast, namely the oxidation of the transcription factor Yap1 by the peroxidase Orp1. It has remained unclear whether the protein oxidase function of Orp1 is a singular adaptation or whether it may represent a more general principle. Here we show that Orp1 is in fact not restricted to oxidizing Yap1 but can also form a highly efficient redox relay with the oxidant target protein roGFP (redox-sensitive green fluorescent protein) in mammalian cells. Orp1 mediates near quantitative oxidation of roGFP2 by H(2)O(2), and the Orp1-roGFP2 redox relay effectively converts physiological H(2)O(2) signals into measurable fluorescent signals in living cells. Furthermore, the oxidant relay phenomenon is not restricted to Orp1 as the mammalian peroxidase Gpx4 also mediates oxidation of proximal roGFP2 in living cells. Together, these findings support the concept that certain peroxidases harbor an intrinsic and powerful capacity to act as H(2)O(2)-dependent protein thiol oxidases when they are recruited into proximity of oxidizable target proteins.

  16. A shock tube study of OH + H(2)O(2) --> H(2)O + HO(2) and H(2)O(2) + M --> 2OH + M using laser absorption of H(2)O and OH.

    Science.gov (United States)

    Hong, Zekai; Cook, Robert D; Davidson, David F; Hanson, Ronald K

    2010-05-13

    The rate constants of the reactions: (1) H2O2+M-->2OH+M, (2) OH+H2O2-->H2O+HO2 were measured in shock-heated H(2)O(2)/Ar mixtures using laser absorption diagnostics for H(2)O and OH. Time-histories of H(2)O were monitored using tunable diode laser absorption at 2550.96 nm, and time-histories of OH were achieved using ring dye laser absorption at 306 nm. Initial H(2)O(2) concentrations were also determined utilizing the H(2)O diagnostic. On the basis of simultaneous time-history measurements of OH and H(2)O, k(2) was found to be 4.6 x 10(13) exp(-2630 K/T) [cm(3) mol(-1) s(-1)] over the temperature range 1020-1460 K at 1.8 atm; additional measurements of k(2) near 1 atm showed no significant pressure dependence. Similarly, k(1) was found to be 9.5 x 10(15) exp(-21 250 K/T) [cm(3) mol(-1) s(-1)] over the same temperature and pressure range.

  17. Research on the degradation 1,2,4-trichlorobenzene by O3/H2O2/UV process%O3/H2O2/UV降解1,2,4-三氯苯的研究

    Institute of Scientific and Technical Information of China (English)

    孙云娜; 魏东洋; 陆桂英; 贾晓珊; 李杰; 许振成

    2013-01-01

    采用O3/H2O2/UV工艺处理1,2,4-三氯苯(TCB)模拟废水,考察了TCB初始浓度、pH、H2O2投加量及O3转化率等因素对O3/H2O2/UV降解TCB的影响,推断了TCB可能的降解途径.结果表明:(1)H2O2、O3、UV、O3/H2O2、O3/H2 O2/UV 5种体系对TCB的降解效果为H2O2 <UV<O3 <O3/H2O2 <O3/H2O2/UV.(2)O3/H2O2/UV对TCB降解的单因素实验表明,TCB初始浓度越小、O3转化率越高,TCB去除率越大;H2O2的投加量存在一个最佳值,低于或高于这个最佳值都会导致TCB去除率的下降;在碱性条件下,TCB的降解效果更佳.(3)推测O3/H2O2/UV工艺降解TCB的机制主要为TCB与·OH的反应过程,其历程可分为3步:反应初期阶段,苯环上的C-Cl被·OH攻击,产生羟基化氯苯化合物;苯环得到活化,·OH进攻苯环,产生低氯代苯类物质;羟基化合物破环,生成小分子有机酸.%The O3/H2O2/UV combination process was employed to treat the simulated 1,2,4-trichlorobenzene (TCB) containing wastewater. The effect of initial TCB concentration, pH, H2O2 dosage and ozone transform rate on TCB removal efficiency was investigated. The potential degradation pathway of TCB was proposed with the help of GC,GC/MS and HPLC analysis. Results showed that the removal efficiency of TCB in 5 degradation system (H2O2 , O3,UV,O3/H2O2,O3/H2O2/UV) followed the order of H2O2 <UV<03 <O3/H2O2 <O3/H2 O2/UV. The single-factor test of O3/H2O2/UV degradation system showed that higher TCB removal efficiency always found in system with lower initial TCB efficiency or higher ozone transform rate. H2O2 dosage had an optimum value, below or above the optimum value could reduce the TCB removal efficiency. Alkaline condition of O3/H2O2/UV process was in favor to the TCB degradation. The mechanism of TCB degradation in O3/H2O2/UV system was the reaction between TCB and o OH. In the early stages of degradation, the C-Cl bond in benzene rings was attacked by o OH and produced hy-droxylation chlorobenzene

  18. Mechanistic Investigation into Olefin Epoxidation with H2O2 Catalyzed by Aqua‐Coordinated Sandwich‐Type Polyoxometalates: Role of the Noble Metal and Active Oxygen Position

    Science.gov (United States)

    Ci, Chenggang; Liu, Hongsheng

    2016-01-01

    Abstract Aqua‐coordinated sandwich‐type polyoxometalates (POMs), {[WZnTM2(H2O)2](ZnW9O34)2}n− (TM=RhIII, PdII, and PtII), catalyze olefin epoxidation with hydrogen peroxide and have been well established, and they present an advance toward the utilization of olefins. To elucidate the epoxidation mechanism, we systematically performed density functional calculations. The reaction proceeds through a two‐step mechanism: activation of H2O2 and oxygen transfer. The aqua‐coordinated complexes show two distinct H2O2 activation pathways: “two‐step” and “concerted”. The concerted processes are more facile and proceed with similar and rate‐determining energy barriers at the Rh‐, Pd‐, and Pt‐containing transition states, which agrees well with the experimental results. Next, the resulting TM−OH−(μ‐OOH) intermediate transfers an O atom to olefin to form an epoxide. The higher reactivity of the Rh‐containing POM is attributed to more interactions between the Rh and hydroperoxo unit. We also calculated all active oxygen positions to locate the most favorable pathway. The higher reactivity of the two‐metal‐bonded oxygen position is predominantly ascribed to its lower stereoscopic hindrance. Furthermore, the presence of one and two explicit water solvent molecules significantly reduces the energy barriers, making these sandwich POMs very efficient for the olefin epoxidation with H2O2. PMID:27777840

  19. Alleviation of drought stress by mycorrhizas is related to increased root H2O2 efflux in trifoliate orange

    Science.gov (United States)

    Huang, Yong-Ming; Zou, Ying-Ning; Wu, Qiang-Sheng

    2017-01-01

    The Non-invasive Micro-test Technique (NMT) is used to measure dynamic changes of specific ions/molecules non-invasively, but information about hydrogen peroxide (H2O2) fluxes in different classes of roots by mycorrhiza is scarce in terms of NMT. Effects of Funneliformis mosseae on plant growth, H2O2, superoxide radical (O2·−), malondialdehyde (MDA) concentrations, and H2O2 fluxes in the taproot (TR) and lateral roots (LRs) of trifoliate orange seedlings under well-watered (WW) and drought stress (DS) conditions were studied. DS strongly inhibited mycorrhizal colonization in the TR and LRs, whereas mycorrhizal inoculation significantly promoted plant growth and biomass production. H2O2, O2·−, and MDA concentrations in leaves and roots were dramatically lower in mycorrhizal seedlings than in non-mycorrhizal seedlings under DS. Compared with non-mycorrhizal seedlings, mycorrhizal seedlings had relatively higher net root H2O2 effluxes in the TR and LRs especially under WW, as well as significantly higher total root H2O2 effluxes in the TR and LRs under WW and DS. Total root H2O2 effluxes were significantly positively correlated with root colonization but negatively with root H2O2 and MDA concentrations. It suggested that mycorrhizas induces more H2O2 effluxes of the TR and LRs, thus, alleviating oxidative damage of DS in the host plant. PMID:28176859

  20. H2O Formation in C-rich AGB Winds

    NARCIS (Netherlands)

    R. Lombaert; L. Decin; P. Royer; A. de Koter; N.L.J. Cox; J. De Ridder; T. Khouri; M. Agúndez; J.A.D.L. Blommaert; J. Gernicharo; E. González-Alfonso; M.A.T. Groenewegen; F. Kerschbaum; D. Neufeld; B. Vandenbussche; C. Waelkens

    2014-01-01

    The Herschel detection of warm H2O vapor emission from C-rich winds of AGB stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H2O formation. In the first, penetration of UV interstellar radiation through a clumpy circumstellar medi

  1. Photoluminescence Probing of Complex H2O Adsorption on InGaN/GaN Nanowires.

    Science.gov (United States)

    Maier, Konrad; Helwig, Andreas; Müller, Gerhard; Hille, Pascal; Teubert, Jörg; Eickhoff, Martin

    2017-02-08

    We demonstrate that the complex adsorption behavior of H2O on InGaN/GaN nanowire arrays is directly revealed by their ambient-dependent photoluminescence properties. Under low-humidity, ambient-temperature, and low-excitation-light conditions, H2O adsorbates cause a quenching of the photoluminescence. In contrast, for high humidity levels, elevated temperature, and high excitation intensity, H2O adsorbates act as efficient photoluminescence enhancers. We show that this behavior, which can only be detected due to the low operation temperature of the InGaN/GaN nanowires, can be explained on the basis of single H2O adsorbates forming surface recombination centers and multiple H2O adsorbates forming surface passivation layers. Reversible creation of such passivation layers is induced by the photoelectrochemical splitting of adsorbed water molecules and by the interaction of reactive H3O(+) and OH(-) ions with photoactivated InGaN surfaces. Due to electronic coupling of adsorbing molecules with photoactivated surfaces, InGaN/GaN nanowires act as sensitive nanooptical probes for the analysis of photoelectrochemical surface processes.

  2. Scavenging of H2O2 by mouse brain mitochondria.

    Science.gov (United States)

    Starkov, Anatoly A; Andreyev, Alexander Yu; Zhang, Steven F; Starkova, Natalia N; Korneeva, Maria; Syromyatnikov, Mikhail; Popov, Vasily N

    2014-12-01

    Mitochondrial reactive oxygen species (ROS) metabolism is unique in that mitochondria both generate and scavenge ROS. Recent estimates of ROS scavenging capacity of brain mitochondria are surprisingly high, ca. 9-12 nmol H2O2/min/mg, which is ~100 times higher than the rate of ROS generation. This raises a question whether brain mitochondria are a source or a sink of ROS. We studied the interaction between ROS generation and scavenging in mouse brain mitochondria by measuring the rate of removal of H2O2 added at a concentration of 0.4 μM, which is close to the reported physiological H2O2 concentrations in tissues, under conditions of low and high levels of mitochondrial H2O2 generation. With NAD-linked substrates, the rate of H2O2 generation by mitochondria was ~50-70 pmol/min/mg. The H2O2 scavenging dynamics was best approximated by the first order reaction equation. H2O2 scavenging was not affected by the uncoupling of mitochondria, phosphorylation of added ADP, or the genetic ablation of glutathione peroxidase 1, but decreased in the absence of respiratory substrates, in the presence of thioredoxin reductase inhibitor auranofin, or in partially disrupted mitochondria. With succinate, the rate of H2O2 generation was ~2,200-2,900 pmol/min/mg; the scavenging of added H2O2 was masked by a significant accumulation of generated H2O2 in the assay medium. The obtained data were fitted into a simple model that reasonably well described the interaction between H2O2 scavenging and production. It showed that mitochondria are neither a sink nor a source of H2O2, but can function as both at the same time, efficiently stabilizing exogenous H2O2 concentration at a level directly proportional to the ratio of the H2O2 generation rate to the rate constant of the first order scavenging reaction.

  3. Hydrothermal Assembly and Structural Characterization of a Novel 3D Coordination Polymer: [Cd2Zn(BTC)2(H2O)4]n·2nH2O

    Institute of Scientific and Technical Information of China (English)

    陈建新; 刘世雄

    2005-01-01

    A hydrothermal reaction of 1,3,5-benzene-tricarboxylic acid (H3BTC) with cad- mium acetate, zinc acetate and pyridine led to the formation of pink crystals of [Cd2Zn(BTC)2- (H2O)4]n·2nH2O 1. Single-crystal X-ray diffraction analysis has revealed that 1 (Cd2ZnC18H18O18) crystallizes in the monoclinic system, space group C2/c with a = 19.4328(7), b = 7.1420(3), c = 18.0426(5)(A), β = 118.035(1)o, V = 2210.3(1) (A)3, Mr = 812.49, Dc = 2.442 g/cm3, Z = 4, μ(MoKα) = 3.081 mm-1 and F(000) =1584. A total of 10735 reflections were collected, of which 2544 were unique. The structure was refined to R = 0.0200 and wR = 0.0603 for 2388 observed reflections with I>2σ(I). The crystal structure consists of cadmium(II)/zinc(II) carboxylates of BTC as well as coordination and discrete water molecules. Extension of the coordination geometry around three metal centers (Cd(1), Cd(2) and Zn(1)), two BTC3- ligands and four coordinated water molecules generates a three-dimensional coordination polymer.

  4. Ionization chemistry in the H2O-dominant atmospheres of the icy moons

    Science.gov (United States)

    Shematovich, V. I.; Johnson, R. E.

    2007-08-01

    The main pathways of the ionization chemistry for pure H2O- and mixed H2O+O2+CO2+NH3+CH4 atmospheres which are representative for neutral and ionized atmospheres of the icy bodies in the Jovian and Saturnian systems are discussed. The gaseous envelopes of the icy moons of the giant planets are formed usually due to the surface radiolysis by the solar UV radiation and energetic magnetospheric plasma (Johnson, 1990). The standard astrochemical UMIST2005 (UDFA05) network is used to infer the main chemical pathways of ionization chemistry in the pure or with admixtures of other volatile molecules water vapor atmospheres. In case of the H2O- dominant atmosphere the parent H2O molecules are easily dissociated and ionized by the solar UVradiation and the energetic magnetospheric electrons. These impact processes result in the formation of the secondary neutral and ionized products - chemically active radicals O and OH, and H+, H2+, O+, OH+, and H2O+ ions. Secondary ions have admixture abundances in the H2O-dominant atmospheres, because they are efficiently transformed to H3O+ hydroxonium ions in the fast ion-molecular reactions. The major H3O+ hydroxonium ion does not chemically interact with other neutrals, and is destroyed in the dissociative recombination with thermal electrons mainly reproducing the chemically simple H, H2, O, and OH species. In case of the mixed H2O+O2-dominant atmosphere corresponding to the near-surface atmospheres of icy moons (Shematovich et al., 2005), the ionization chemistry results in the formation of the second major ion O2+ - because ion of molecular oxygen has the lower ionization potential comparing with other parent species -H2, H2O, CO2. The H+, O+, OH+, and H2O+ ions can be easily converted to O2+ ions through the ion-molecular reactions. In case of significant admixture of molecular hydrogen it is possible to transfer the O2+ ions to the O2H+ ions through the fast reaction with H2 and further to the H3O+ ions through the ion

  5. [Degradation of norfloxacin by nano-Fe3O4/H2O2].

    Science.gov (United States)

    Zhang, Di; Wang, Yi-Xuan; Niu, Hong-Yun; Meng, Zhao-Fu

    2011-10-01

    The degradation of norfloxacin in aquatic environment was studied in the presence of Fe3O4 nanoparticles and H2O2. The effects of solution pH, temperature, dose of catalysts and concentration of H2O2 on norfloxacin degradation were surveyed. The degradation behaviors of different substrates by nano-Fe3O4/H2O2 were investigated and the reaction mechanism of norfloxacin was discussed. The results showed that the reaction was strongly pH-dependent and favored in acidic solution (pH = 3.5). The removal efficiency of norfloxacin was enhanced with the increase of temperature, catalysts dosage and H2O2 concentration. The degradation efficiency of norfloxacin by nano-Fe3O4/H2O2 was significantly higher than those of sulfathiazole, phenolic and aniline compounds. In the presence of 4.4 mmol x L(-1) of H2O2, 0.80 g x L(-1) of Fe3O4 and T = 303 K, norfloxacin was degraded completely in 5 min. The F element in norfloxacin molecule existed totally as F(-) in solution within 5 min, and the removal efficiency of total organic carbon was 57% in 1 h. In the ESR spectrum of nano-Fe3O4/H2O2 system, the characteristic peaks of BMPO-*OH adduct was detected, however, the intensity of the peaks was reduced to 5% with the addition of tert-butanol, a strong *OH scavenger, and the degradation efficiency of norfloxacin was correspondingly decreased to 10% in 1 h. These results indicated that *OH played an important role on norfloxacin degradation, and the reaction proceeded based on a heterogeneous Fenton-like system.

  6. Characterization of titanium dioxide nanoparticles modified with polyacrylic acid and H2O2 for use as a novel radiosensitizer.

    Science.gov (United States)

    Morita, Kenta; Miyazaki, Serika; Numako, Chiya; Ikeno, Shinya; Sasaki, Ryohei; Nishimura, Yuya; Ogino, Chiaki; Kondo, Akihiko

    2016-12-01

    An induction of polyacrylic acid-modified titanium dioxide with hydrogen peroxide nanoparticles (PAA-TiO2/H2O2 NPs) to a tumor exerted a therapeutic enhancement of X-ray irradiation in our previous study. To understand the mechanism of the radiosensitizing effect of PAA-TiO2/H2O2 NPs, analytical observations that included DLS, FE-SEM, FT-IR, XAFS, and Raman spectrometry were performed. In addition, highly reactive oxygen species (hROS) which PAA-TiO2/H2O2 NPs produced with X-ray irradiation were quantified by using a chemiluminescence method and a EPR spin-trapping method. We found that PAA-TiO2/H2O2 NPs have almost the same characteristics as PAA-TiO2. Surprisingly, there were no significant differences in hROS generation. However, the existence of H2O2 was confirmed in PAA-TiO2/H2O2 NPs, because spontaneous hROS production was observed w/o X-ray irradiation. In addition, PAA-TiO2/H2O2 NPs had a curious characteristic whereby they absorbed H2O2 molecules and released them gradually into a liquid phase. Based on these results, the H2O2 was continuously released from PAA-TiO2/H2O2 NPs, and then released H2O2 assumed to be functioned indirectly as a radiosensitizing factor.

  7. Sources of superoxide/H2O2 during mitochondrial proline oxidation

    Directory of Open Access Journals (Sweden)

    Renata L.S. Goncalves

    2014-01-01

    Full Text Available p53 Inducible gene 6 (PIG6 encodes mitochondrial proline dehydrogenase (PRODH and is up-regulated several fold upon p53 activation. Proline dehydrogenase is proposed to generate radicals that contribute to cancer cell apoptosis. However, there are at least 10 mitochondrial sites that can produce superoxide and/or H2O2, and it is unclear whether proline dehydrogenase generates these species directly, or instead drives production by other sites. Amongst six cancer cell lines, ZR75-30 human breast cancer cells had the highest basal proline dehydrogenase levels, and mitochondria isolated from ZR75-30 cells consumed oxygen and produced H2O2 with proline as sole substrate. Insects use proline oxidation to fuel flight, and mitochondria isolated from Drosophila melanogaster were even more active with proline as sole substrate than ZR75-30 mitochondria. Using mitochondria from these two models we identified the sites involved in formation of superoxide/H2O2 during proline oxidation. In mitochondria from Drosophila the main sites were respiratory complexes I and II. In mitochondria from ZR75-30 breast cancer cells the main sites were complex I and the oxoglutarate dehydrogenase complex. Even with combinations of substrates and respiratory chain inhibitors designed to minimize the contributions of other sites and maximize any superoxide/H2O2 production from proline dehydrogenase itself, there was no significant direct contribution of proline dehydrogenase to the observed H2O2 production. Thus proline oxidation by proline dehydrogenase drives superoxide/H2O2 production, but it does so mainly or exclusively by providing anaplerotic carbon for other mitochondrial dehydrogenases and not by producing superoxide/H2O2 directly.

  8. Sources of superoxide/H2O2 during mitochondrial proline oxidation.

    Science.gov (United States)

    Goncalves, Renata L S; Rothschild, Daniel E; Quinlan, Casey L; Scott, Gary K; Benz, Christopher C; Brand, Martin D

    2014-01-01

    p53 Inducible gene 6 (PIG6) encodes mitochondrial proline dehydrogenase (PRODH) and is up-regulated several fold upon p53 activation. Proline dehydrogenase is proposed to generate radicals that contribute to cancer cell apoptosis. However, there are at least 10 mitochondrial sites that can produce superoxide and/or H2O2, and it is unclear whether proline dehydrogenase generates these species directly, or instead drives production by other sites. Amongst six cancer cell lines, ZR75-30 human breast cancer cells had the highest basal proline dehydrogenase levels, and mitochondria isolated from ZR75-30 cells consumed oxygen and produced H2O2 with proline as sole substrate. Insects use proline oxidation to fuel flight, and mitochondria isolated from Drosophila melanogaster were even more active with proline as sole substrate than ZR75-30 mitochondria. Using mitochondria from these two models we identified the sites involved in formation of superoxide/H2O2 during proline oxidation. In mitochondria from Drosophila the main sites were respiratory complexes I and II. In mitochondria from ZR75-30 breast cancer cells the main sites were complex I and the oxoglutarate dehydrogenase complex. Even with combinations of substrates and respiratory chain inhibitors designed to minimize the contributions of other sites and maximize any superoxide/H2O2 production from proline dehydrogenase itself, there was no significant direct contribution of proline dehydrogenase to the observed H2O2 production. Thus proline oxidation by proline dehydrogenase drives superoxide/H2O2 production, but it does so mainly or exclusively by providing anaplerotic carbon for other mitochondrial dehydrogenases and not by producing superoxide/H2O2 directly.

  9. Formation of glycine from HCN and H2O: A computational mechanistic study

    Science.gov (United States)

    Lee, Hyun Moo; Choe, Joong Chul

    2017-05-01

    The potential energy surfaces for the formation of glycine from HCN and H2O were determined from CBS-QB3 calculations. After the formation of a HCN trimer, amino malononitrile, amino malononitrile monoamide (3) was formed by a water addition reaction. Two pathways were found for the subsequent reaction, 3 + 2H2O → glycine + HNCO + NH3. One pathway involving an amino ketone was much more favored than the other pathway involving glycinamide. Addition of a water molecule as a catalyst greatly enhanced steps occurring by hydrogen rearrangement.

  10. Pyruvate protects pathogenic spirochetes from H2O2 killing.

    Directory of Open Access Journals (Sweden)

    Bryan Troxell

    Full Text Available Pathogenic spirochetes cause clinically relevant diseases in humans and animals, such as Lyme disease and leptospirosis. The causative agent of Lyme disease, Borrelia burgdorferi, and the causative agent of leptospirosis, Leptospria interrogans, encounter reactive oxygen species (ROS during their enzootic cycles. This report demonstrated that physiologically relevant concentrations of pyruvate, a potent H2O2 scavenger, and provided passive protection to B. burgdorferi and L. interrogans against H2O2. When extracellular pyruvate was absent, both spirochetes were sensitive to a low dose of H2O2 (≈0.6 µM per h generated by glucose oxidase (GOX. Despite encoding a functional catalase, L. interrogans was more sensitive than B. burgdorferi to H2O2 generated by GOX, which may be due to the inherent resistance of B. burgdorferi because of the virtual absence of intracellular iron. In B. burgdorferi, the nucleotide excision repair (NER and the DNA mismatch repair (MMR pathways were important for survival during H2O2 challenge since deletion of the uvrB or the mutS genes enhanced its sensitivity to H2O2 killing; however, the presence of pyruvate fully protected ΔuvrB and ΔmutS from H2O2 killing further demonstrating the importance of pyruvate in protection. These findings demonstrated that pyruvate, in addition to its classical role in central carbon metabolism, serves as an important H2O2 scavenger for pathogenic spirochetes. Furthermore, pyruvate reduced ROS generated by human neutrophils in response to the Toll-like receptor 2 (TLR2 agonist zymosan. In addition, pyruvate reduced neutrophil-derived ROS in response to B. burgdorferi, which also activates host expression through TLR2 signaling. Thus, pathogenic spirochetes may exploit the metabolite pyruvate, present in blood and tissues, to survive H2O2 generated by the host antibacterial response generated during infection.

  11. Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation

    CERN Document Server

    Arasa, Carina; Kroes, Geert-Jan; Walsh, Catherine; van Dishoeck, Ewine F

    2015-01-01

    The HDO/H2O ratio in interstellar gas is often used to draw conclusions on the origin of water in star-forming regions and on Earth. In cold cores and in the outer regions of protoplanetary disks, gas-phase water comes from photodesorption of water ice. We present fitting formulae for implementation in astrochemical models using photodesorption efficiencies for all water ice isotopologues obtained using classical molecular dynamics simulations. We investigate if the gas-phase HDO/H2O ratio reflects that present in the ice or whether fractionation can occur during photodesorption. Probabilities for the top four monolayers are presented for photodesorption of X (X=H,D) atoms, OX radicals, and X2O and HDO molecules following photodissociation of H2O, D2O, and HDO in H2O amorphous ice at temperatures from 10-100 K. Isotope effects are found for all products: (1) H atom photodesorption probabilities from H2O ice are larger than those for D atom photodesorption from D2O ice by a factor of 1.1; the ratio of H and D ...

  12. Ab initio study of H2O and water-chain-induced properties of carbon nanotubes

    Science.gov (United States)

    Agrawal, B. K.; Singh, V.; Pathak, A.; Srivastava, R.

    2007-05-01

    We perform an ab initio study of the motion of the nano sized water dimer through a single-walled carbon nanotube (SWCNT), the stability of an encapsulated one-dimensional (1D) water chain inside SWCNT, and the H2O -induced structural, energetic, electronic, and optical properties of the SWCNTs. The adsorption of the water molecules is caused by the dispersion forces, i.e., the van der Waals (vdW) interactions. Thus, the role of the vdW interactions in the estimation of the BE for the weakly bound adsorbates cannot be ignored as has been done in several earlier publications. We find that a single H2O molecule or single water dimer or a 1D chain of water dimers is trapped inside the medium-sized (6,6) carbon nanotube placed in vacuum. However, the H2O molecule or water dimer may be transmitted in case the tube is surrounded by water or water vapor at high vapor pressure at high temperatures. On the other hand, a chain of single H2O molecules or more number of the encapsulated H2O molecules is very weakly coupled to the wide (10,10) carbon nanotube and can, thus, easily transmit through the carbon nanotube in agreement with the recent experiments. Further, appreciable adsorption both inside and on the surface of the (10,10) carbon nanotube is predicted in concurrence with the experiments. The small (medium-sized) diameter tubes will adsorb strongly (accommodate) the water molecules outside (inside) the nanotubes. The H2O adsorption converts the conducting small-diameter zigzag (5,0) tube into a semiconductor. Further, the adsorption reduces the band gap of the semiconducting achiral zigzag (10,0) nanotube but increases the band gap of a chiral semiconducting (4,2) tube. The adsorbed H2O molecules increase the electrical conductivity in agreement with the experiment. The overall peak structure in the optical absorption for the pristine tube is not altered significantly by the adsorption except for small alterations in the energy locations and the relative intensities

  13. Investigating the adsorption of H2O on ZnO nanoclusters by first principle calculations

    KAUST Repository

    Al-Sunaidi, Abdullah A.

    2011-04-01

    The interaction of a single H2O molecule on selected ZnO nanoclusters is investigated by carrying out calculations based on the density-functional theory at the hybrid-GGA (B97-2) level. These clusters have ring, drum, tube and bubble shapes and their physical properties like the binding energy and the band gap energy depend strongly on the shape and size of the cluster. Depending on the stability of the cluster, H2O show both chemisorption and dissociation on the surfaces of the clusters. We analyzed the effect of H2O adsorption on the properties of clusters of size n = 12 via the density of state, HOMO-LUMO orbitals and the changes in the IR frequencies. © 2011 Elsevier B.V. All rights reserved.

  14. Diels-Alder addition to H2O@C60 an electronic and structural study

    Science.gov (United States)

    Reveles, J. Ulises; Govinda, K. C.; Baruah, Tunna; Zope, Rajendra R.

    2017-10-01

    Exohedral reactivity of endohedral fullerenes has aroused a significant interest because of its potential applications. The present letter examines the effect of an entrapped single water molecule on the reactivity of C60. We study the thermodynamics and kinetics of a Diels-Alder reaction occurring at all non-identical bonds of free C60 and H2O@C60. Our calculations show that encapsulation of water does not have a significant effect on H2O@C60 reactivity compared to C60, as attested by the investigation of the reaction under several orientations of H2O inside C60. Reaction and activation energies indicate that [6,6] bonds are the most reactive sites.

  15. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex: [NdFe(CN)6(DMF)4(H2O)3]·H2O

    Institute of Scientific and Technical Information of China (English)

    李建荣; 郭国聪; 王明盛; 周国伟; 卜显和; 黄锦顺

    2003-01-01

    A new bimetallic cyano-bridged complex, [NdFe(CN)6(DMF)4(H2O)3]@H2O (DMF= N,N-dimethylformamide) 1, has been obtained by the reaction of hexacyanoferrate potassium with neodymium (Ⅲ) chloride in H2O/EtOH/DMF (volume ratio: 2:2:1), and its structure was determined by means of single-crystal X-ray diffraction. The compound crystallizes in space group P21/n of monoclinic system with cell parameters: a = 17.646(1), b = 8.9011(3), c = 19.945(1) A, β = 95.835(2)°, V= 3116.6(3) A3, Z = 4, Dc = 1.536 g/cm3, Mr = 720.66, F(000) = 1456, μ = 2.166 mm-1, R = 0.0386, wR = 0.1120 and S = 1.061. The central Nd (Ⅲ) ion is coordinated by seven oxygen atoms of four DMF molecules and three water molecules and one nitrogen atom of the bridging cyanide in a slightly distorted square-antiprism arrangement, and the Fe (Ⅲ) ion is in an almost octahedral environment coordinated to six cyano-ligands, of which one cyanide ligand bridges the Nd (Ⅲ) ion to form a bimetallic complex. Molecules of complexes in the crystal lattice are held together by hydrogen bonding, forming a three-dimensional framework.

  16. Syntheses and Crystal Structures of Two Cyano-bridged Bimetallic Complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O and [La(DMSO)4(H2O)3Co(CN)6]·H2O (DMSO = Dimethylsulfoxide)

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen-Qian; CHEN Wen-Tong; LIU Xi; CAI Li-Zhen; GUO Guo-Cong; HUANG Jin-Shun

    2006-01-01

    Two new bimetallic cyano-bridged complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O 1 and [La(DMSO)4(H2O)3Co(CN)6]·H2O 2 have been prepared by the ball milling reaction method and structurally characterized by X-ray single-crystal structure analyses. Crystallographic data for 1:C14H32CeFeN6O8S4, Mr = 736.67, monoclinic, space group P21/n, a = 14.952(1), b =13.7276(9), c = 15.392(1) (A), β = 108.288(1)°, V = 2999.6(4) (A)3, Z = 4, Dc= 1.631 g/cm3,μ =2.304 mm-1, F(000) = 1480, R = 0.0593 and wR = 0.1611; and those for 2: C14H32CoLaN6O8S4,Mr=738.54, monoclinic, space group P21/n, a = 14.945(3), b = 13.731(3), c = 15.300(3) (A), β=107.806(1)°, V= 2989.3(11) (A)3, Z = 4, Dc = 1.641 g/cm3,μ = 2.288 mm-1, F(000) = 1480, R =0.0383 and wR = 0.1132. In both complexes the lanthanide ion is eight-coordinated in a square antiprism arrangement, and the Fe(Ⅲ) or Co(Ⅲ) ion in a nearly regular octahedral environment.The [LnM(CN)6(DMSO)4(H2O)3]·H2O (Ln = Ce and M = Fe for 1; Ln = La and M = Co for 2)species are held together via hydrogen bonds by coordinated water molecules, lattice water molecules and nitrogen atoms of cyanide groups to form a three-dimensional framework.

  17. [(H2O)(terpy)Mn(μ-O)2Mn(terpy)(OH2)](NO3)3 (terpy = 2,2′:6,2″-terpyridine) and its relevance to the oxygen-evolving complex of photosystem II examined through pH dependent cyclic voltametry

    Science.gov (United States)

    Cady, Clyde W.; Shinopoulos, Katherine E.; Crabtree, Robert H.; Brudvig, Gary W.

    2010-01-01

    Photosynthetic water oxidation occurs naturally at a tetranuclear manganese center in the photosystem II protein complex. Synthetically mimicking this tetramanganese center, known as the oxygen-evolving complex (OEC), has been an ongoing challenge of bioinorganic chemistry. Most past efforts have centered on water-oxidation catalysis using chemical oxidants. However, solar energy applications have drawn attention to electrochemical methods. In this paper, we examine the electrochemical behavior of the biomimetic water-oxidation catalyst [(H2O)(terpy)Mn(μ-O)2Mn(terpy)(H2O)](NO3)3 [terpy = 2,2′:6′,2″-terpyridine] (1) in water under a variety of pH and buffered conditions and in the presence of acetate that binds to 1 in place of one of the terminal water ligands. These experiments will show that 1 not only exhibits proton-coupled electron-transfer reactivity analogous to the OEC, but also may be capable of electrochemical oxidation of water to oxygen. PMID:20372724

  18. Identification of symmetry, structure and defects of dopant Mn(II) ions in Zn(C 3H 3O 4) 2(H 2O) 2 by single crystal EPR technique

    Science.gov (United States)

    Natarajan, B.; Mithira, S.; Sambasiva Rao, P.

    2008-12-01

    In order to understand the symmetry, structure and defects of Mn(II) impurity incorporated in diaquabis[malonato(1-)-κ 2O,O'] zinc(II), single crystal EPR studies have been carried out at X-band frequencies at room temperature. Angular variation in the three orthogonal planes shows the presence of two defects, having a relatively large and small zero-field splitting parameter ( D), with orthorhombic symmetry. The spin-Hamiltonian parameters, estimated from the three mutually orthogonal crystal rotations, are: Defect I:g xx = 1.959, g yy = 1.998, g zz = 2.011; A xx = -8.73, A yy = -8.55, A zz = -9.10 mT; D xx = 5.58, D yy = 1.33, D zz = -6.91 mT. Defect II:g xx = 2.015, g yy = 1.996, g zz = 2.004; A xx = -8.18, A yy = -8.00, A zz = -8.58 mT; D xx = 33.48, D yy = 6.92, D zz = -40.40 mT. The observed large zero-field tensor for Defect II is due to the steric effects caused by the two malonate rings. The location of the two interstitial defects has been determined from the X-ray data of the host lattice. The powder EPR spectrum also confirms the chemical inequivalence of the two defects. The optical absorption spectrum shows the characteristic of Mn(II) ions in distorted octahedral symmetry.

  19. Synthesis and Structural Determination of Nine-Coordinate K[GdIII(edta)(H2O)3]·5H2O

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The title complex K[GdIII(edta)(H2O)3]·5H2O was synthesized, where edta denotes ethylenediamine-tetraacetic acid. The crystal and molecular structure of the complex were determined by single-crystal X-ray structure analysis. The crystal belongs to an orthorhombic crystal system and an Fdd2 space group. The complex anion [GdIII(edta)(H2O)3]- has a pseudo-monocapped square antiprismatic nine-coordinate structure in which six coordinate atoms (two N and four O) are from an edta ligand and three water molecules coordinate to GdIII ion directly. It can be predicted that GdIII ion can also form a nine-coordinate complex with ttha (triethylenetetraminehexaacetic acid) ligand, so the GdIII complex anion [GdIII(Httha)]2- can supply a free non-coordinate carboxyl group used for molecular embellishment in some biological molecules to form a contrast agent of Magnetic Resonance Imagine (MRI) with targeting function.

  20. Crystal structure of [Y6(μ6-O(μ3-OH8(H2O24]I8·8H2O

    Directory of Open Access Journals (Sweden)

    François Le Natur

    2014-12-01

    Full Text Available The crystal structure of the title compound {systematic name: octa-μ3-hydroxido-μ6-oxido-hexakis[tetraaquayttrium(III] octaiodide octahydrate}, is characterized by the presence of the centrosymmetric molecular entity [Y6(μ6-O(μ3-OH8(H2O24]8+, in which the six Y3+ cations are arranged octahedrally around a μ6-O atom at the centre of the cationic complex. Each of the eight faces of the Y6 octahedron is capped by an μ3-OH group in the form of a distorted cube. In the hexanuclear entity, the Y3+ cations are coordinated by the central μ6-O atom, the O atoms of four μ3-OH and of four water molecules. The resulting coordination sphere of the metal ions is a capped square-antiprism. The crystal packing is quite similar to that of the orthorhombic [Ln6(μ6-O(μ3-OH8(H2O24]I8·8H2O structures with Ln = La—Nd, Eu—Tb, Dy, except that the title compound exhibits a slight monoclinic distortion. The proximity of the cationic complexes and the lattice water molecules leads to the formation of a three-dimensional hydrogen-bonded network of medium strength.

  1. Structural morphology of gypsum (CaSO 4·2H 2O), brushite (CaHPO 4·2H 2O) and pharmacolite (CaHAsO 4·2H 2O)

    Science.gov (United States)

    Heijnen, W. M. M.; Hartman, P.

    1991-01-01

    A uniform description of the crystal structures of gypsum ( CaSO4·2 H2O), brushite ( CaHPO4·2 H2O) and pharmacolite ( CaHAsO4·2 H2O) is presented. From these structures, a PBC analysis leads to the following F forms: {020}, {011}, {⦶1}11 {120} and {⦶1}22 (for brushite and pharmacolite the counterfaces ( ⦶h⦶k⦶l) are included). Attachment energies of the gypsum F faces have been calculated in an electrostatic point charge model for various charge distributions in the water molecule and in the sulphate ion. The theoretical habits are all platy or tabular {020} with {120}, {011} and {⦶1}11, the latter being smaller than {011}, in disagreement with observation. Arguments are given that {011} can grow in layers {built1}/{2}d 011, and therefore faster, at a supersaturation for which {⦶1}11 cannot grow in half layers, thus removing the discrepancy between theory and experiment. The curious triangular or trapeziumlike habit of brushite has been related to its crystal structure. The polar habit is ascribed to different adsorption of water and cosolutes on opposite faces. The most important forms are {020} with {⦶1}20, 11{⦶1} and {111}, the latter being an S form. Its appearance is ascribed to a habit change.

  2. Global Potential Energy Minima of (H$_{2}$O)$_{n}$ Clusters on Graphite

    CERN Document Server

    Gonzalez, B S; Breton, J; Llorente, J M Gomez

    2007-01-01

    Likely candidates for the global potential energy minima of (H$_{2}$O)$_{n}$ clusters with $n\\leq21$ on the (0001)-surface of graphite are found using basin-hopping global optimization. The potential energy surfaces are constructed using the TIP4P intermolecular potentials for the water molecules (the TIP3P is also explored as a secondary choice), a Lennard-Jones water-graphite potential, and a water-graphite polarization potential that is built from classical electrostatic image methods and takes into account both the perpendicular and parallel electric polarizations of graphite. This potential energy surface produces a rather hydrophobic water-graphite interaction. As a consequence, the water component of the lowest graphite-(H$_{2}$O)$_{n}$ minima is quite closely related to low-lying minima of the corresponding TIP4P (H$_{2}$O)$_{n}$ clusters. In about half of the cases the geometrical substructure of the water molecules in the graphite-(H$_{2}$O)$_{n}$ global minimum coincides with that of the correspond...

  3. Solubility of ammonium paratungstate in the system NH3·H2O-H2O

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The equilibrium solubilities of 5(NH4)O@ 12WO3 @ 5H2O (APT@ 5H2O) were determined at the terminal ammoniaconcentration of 2 mol/L at 87-95℃. Experimental data were regressed. The linear functional relation between the solubilityof APT@ 5H2O and the temperature (t / ℃) is given as y = - 588.08 + 7.28t. The solubility of the species as a function of theterminal ammonia concentration (x / mol@ L-1) is also achieved: y = 36.76 + 18.86x. The solubility of APT@ 5H2O producedby ion-exchange method in China is much lower, which is due to much lower silica, much higher NH4C1, and a smallamount of APT@ 7H2O with low solubility in the APT crystals. APT@ 7H2O forms because of a large amount of NH4Cl andthe low activity of water in the crystallization.

  4. Experimental studies of the formation of cluster ions formed by corona discharge in an atmosphere containing SO2, NH3, and H2O

    Science.gov (United States)

    Pedersen, J. O.; Hvelplund, P.; Støchkel, K.; Enghoff, M. B.; Kurten, T.

    2013-12-01

    We report on studies of ion induced nucleation in a corona discharge taking place in an atmosphere containing SO2, NH3, and H2O at standard temperature and pressure. Positive ions such as H3O+(H2O)n, NH4+(H2O)n, and H+(H2SO4)(H2O)n and negative ions such as HSO5-(H2O)n, SO4-(H2O)n, HSO4-(H2O)n and NO3-(H2O)n have been recorded. Large values of n (> 100) were observed and the experiment indicates the existence of even larger water clusters. In contrast, only clusters with a maximum of 2 sulfuric acid molecules were observed. Fragmentation studies also revealed that the negative ion HSO5-, which has been observed in many studies, in our experiments is contaminated by O2-(HNO3)(H2O) ions, and this may also have been the case in other experiments. Finally an ion with m/z = 232 (where m is the cluster mass in amu and z the charge state), capable of attaching H2O-molecules was observed and studied by fragmentation. Positive ion m/z (mass/charge) spectrum

  5. Incorporation of M(H2O)6(2+) between layers {M(H2O)2Ru2(CO3)4Cl2}n(2n-) (M = Zn, Mn): syntheses, structures and magnetic properties.

    Science.gov (United States)

    Liu, Bin; Jia, Yan-Yan; Yang, Huai-Qing; Yang, Jian-Hui; Xue, Gang-Lin

    2013-12-28

    Isostructural heterometallic diruthenium carbonates KM(H2O)6[M(H2O)2Ru2(CO3)4Cl2]·4H2O [M = Zn (1) and Mn (2)] were synthesized from the reaction of the precursors [Ru2(CO3)4Cl2](5-) and transitional metal ions in aqueous solution. Complexes 1 and 2 show layered structures in which Ru2(II,III) units are linked by four octahedral environment M(H2O)2(2+) ions in a cross fashion and vice versa giving a negative bimetallic square grid layer {M(H2O)2Ru2(CO3)4Cl2}n(3n-). M(H2O)6(2+) ions, linked by K(+) forming zigzag chain {KM(H2O)6}n(3+), are located in the void spaces between the layers. The adjacent bimetallic carbonate layers are connected with K-O and K-Cl bonds, and hydrogen bonding, forming a supramolecular 3D framework structure. Their magnetic properties were characterized in detail, and intralayer ferromagnetic coupling between the Ru2 dimer and Mn(2+) ion, as well as long-range ordering (Tc = 5.2 K) coexistence of domain movement behavior were observed for complex 2.

  6. Agardite-(Y, Cu2+6Y(AsO43(OH6·3H2O

    Directory of Open Access Journals (Sweden)

    Shaunna M. Morrison

    2013-09-01

    Full Text Available Agardite-(Y, with a refined formula of Cu2+5.70(Y0.69Ca0.31[(As0.83P0.17O4]3(OH6·3H2O [ideally Cu2+6Y(AsO43(OH6·3H2O, hexacopper(II yttrium tris(arsenate hexahydroxide trihydrate], belongs to the mixite mineral group which is characterized by the general formula Cu2+6A(TO43(OH6·3H2O, where nine-coordinated cations in the A-site include rare earth elements along with Al, Ca, Pb, or Bi, and the T-site contains P or As. This study presents the first structure determination of agardite-(Y. It is based on the single-crystal X-ray diffraction of a natural sample from Jote West mine, Pampa Larga Mining District, Copiapo, Chile. The general structural feature of agardite-(Y is characterized by infinite chains of edge-sharing CuO5 square pyramids (site symmetry 1 extending down the c axis, connected in the ab plane by edge-sharing YO9 polyhedra (site symmetry -6.. and corner-sharing AsO4 tetrahedra (site symmetry m... Hydroxyl groups occupy each corner of the CuO5-square pyramids not shared by a neighboring As or Y atom. Each YO9 polyhedron is surrounded by three tubular channels. The walls of the channels, parallel to the c axis, are six-membered hexagonal rings comprised of CuO5 and AsO4 polyhedra in a 2:1 ratio, and contain free molecules of lattice water.

  7. Crystal Structure of a Threedimensional Coordination Polymer {[Ca3(μ5-OOCCH2OCH2COO)3(H2O)4]·4H2O}n

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel three-dimensional coordination polymer, {[Ca3(μ5-OOCCH2OCH2COO)3(H2O)4]·4H2O}n, has been synthesized with oxydiacetate as bridge ligand and structurally determined by X-ray crystallography. The crystal belongs to monoclinic, space group C2/c with a = 17.805(2), b = 9.3923(12), c = 17.255(2)(A), β = 107.838(5)°, V = 2746.8(6) (A)3, Mr = 660.58, C12H28Ca3O23, Dc = 1.597 g/cm3, μ = 0.695 mm-1, Z = 4, F(000) = 1376, GOOF = 1.027, R = 0.0303 and wR = 0.0660. In the complex there are two coordination modes for Ca(Ⅱ) ions, one coordinated by three μ5-OOCCH2OCH2COO2- bridge ligands together with two H2O molecules, and the other by five μ5-OOCCH2OCH2COO2- bridge ligands. In both coordination modes each Ca(Ⅱ) ion assumes a distorted dipentapyramidal CaO7 geometry; whereas each oxydiacetate is coordinated with five Ca(Ⅱ) ions and acts as a pentdentates bridge ligand.

  8. Vibrational predissociation of ArH2O

    Science.gov (United States)

    Bissonnette, C.; Clary, D. C.

    1992-12-01

    Accurate close-coupling calculations are used to investigate the vibrational predissociation of ArH2O as a function of the overall rotation J of the van der Waals complex. A full vibrational and rotational basis of H2O states is used in the calculation. The potential energy surface is of a form due to Cohen and Saykally and derived from far-infrared spectra, with an additional term to introduce the dependence on the vibrations of H2O. The linewidths calculated in this work show a maximum at J=6 and it is found that Fermi resonances affect dramatically the magnitude of the calculated linewidths. Good agreement with experimentally measured linewidths of Nesbitt and Lascola is achieved and the calculations provide a simple picture for the J dependence of the linewidths.

  9. A Global PLASIMO Model for H2O Chemistry

    Science.gov (United States)

    Tadayon Mousavi, Samaneh; Koelman, Peter; Graef, Wouter; Mihailova, Diana; van Dijk, Jan; EPG/ Applied Physics/ Eindhoven University of Technology Team; Plasma Matters B. V. Team

    2016-09-01

    Global warming is one of the critical contemporary problems for mankind. Transformation of CO2 into fuels, like CH4, that are transportable with the current infrastructure seems a promising idea to solve this threatening issue. The final aim of this research is to produce CH4 by using microwave plasma in CO2 -H2 O mixture and follow-up catalytic processes. In this contribution we present a global model for H2 O chemistry that is based on the PLASIMO plasma modeling toolkit. The time variation of the electron energy and the species' densities are calculated based on the source and loss terms in plasma due to chemical reactions. The short simulation times of such models allow an efficient assessment and chemical reduction of the H2O chemistry, which is required for full spatially resolved simulations.

  10. [Cd3(H2O)3((O3PCH2)2NH-CH2C6H4-COOH)2].11H2O: a layered cadmium phosphonate with reversible dehydration/hydration properties.

    Science.gov (United States)

    Bauer, Sebastian; Marrot, Jérôme; Devic, Thomas; Férey, Gérard; Stock, Norbert

    2007-11-12

    In a recent systematic study on the influence of the reaction temperature on the structure formation in the system CdCl2/H(HO3PCH2)2NH-CH2C6H4-COOH (H5L) /NaOH, [Cd3(H2O)3((O3PCH2)2NH-CH2C6H4-COOH)2].11H2O was obtained as a microcrystalline compound. We have now been able to elucidate the structure from single-crystal data: triclinic, P; a=5.4503(9), b=12.880(2), and c=16.417(3) A; alpha=67.841(6) degrees, beta=80.633(6) degrees, gamma=87.688(8) degrees, V=1052.9(3) A3; Z=1; R1=0.1143, R2=0.2108 (all data); 0.0705, 0.1823 ((I>2sigmaI)). The structure of [Cd3(H2O)3((O3PCH2)2NH-CH2C6H4-COOH)2].11H2O is built up of cadmium phosphonate layers connected by water-mediated hydrogen bonds between aryl-carboxylic acid groups and water molecules coordinated to Cd2+ ions of adjacent layers (C-OH...H2O...H2O-Cd2+). The title compound was characterized by IR spectroscopy and energy dispersive X-ray, elemental, and thermogravimetric analyses. Furthermore, temperature-dependent X-ray diffraction data are presented. [Cd3(H2O)3((O3PCH2)2NH-CH2C6H4-COOH)2].11H2O can be reversibly dehydrated, and mechanical stress and grinding in the presence of water leads to the intercalation of additional water molecules.

  11. Analysis of environmental stress in plants with the aid of marker genes for H2O2 responses.

    Science.gov (United States)

    Hieno, Ayaka; Naznin, Hushna Ara; Sawaki, Katsunobu; Koyama, Hiroyuki; Sakai, Yusaku; Ishino, Haruka; Hyakumachi, Mitsuro; Yamamoto, Yoshiharu Y

    2013-01-01

    Hydrogen peroxide acts as a signaling molecule mediating the acquisition of tolerance to both biotic and abiotic stresses. Identification of marker genes for H2O2 response could help to intercept the signaling network of stress response of plants. Here, we describe application of marker genes for H2O2 responses to monitoring several abiotic stress responses. Arabidopsis plants were treated with UV-B, high light, and cold stresses, where involvement of H2O2-mediated signaling is known or suggested. Monitoring of these stress responses with molecular markers using quantitative real-time RT-PCR can detect landmark events in the sequential stress responses. These methods can be used for analysis of mutants and transgenic plants to examine natural H2O2 responses that are involved in environmental adaptation.

  12. Synthesis and Structural Characterization of Gd(Ⅱ) Coordination Polymer [Gd2(μ-phth)3(b-pd)(H2O)5]n

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new Gd(Ⅱ) complex [Gd2(μ-phth)3(b-pd)(H2O)5]n (phth = o-phthalato, b-pd = N,N- bipyridine) has been synthesized by the reaction of GdO2 with o-phthalate, H2O and 2,2′-bipyridine. The crystal structure has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P with a = 11.82920(10), b = 13.53550(10), c = 13.7381(2)(A), α = 88.99, β = 66.9120(10), γ = 66.2370(10)°, V = 1826.02(3)(A)3, Dc = 1.915 g/cm3, C34H30N2O17Gd2, Mr = 1053.10, F(000) = 1024, μ = 3.680 mm-1, Z = 2, R = 0.0612 and wR = 0.1320 for 6259 observed reflections (I > 2σ(I)). In the title complex, the Gd(II) ions are bridged by o-phthalate ligands in a bidentate mode, producing a 1D infi- nite chain structure. Each eight-coordinated Gd(Ⅱ) center is coordinated by eight oxygen atoms from phth to give a distorted dodecahedral geometry, and each nine-coordinated Gd(Ⅱ) center is coordi- nated by two N atoms from b-pd and seven oxygen atoms from phth to give a distorted geometry of capped square antiprism. The chains are linked by π-π interactions and hydrogen bonds between oxy- gen atoms of carboxylate groups and H2O molecules and hydrogen atoms of H2O, b-pd and o-phth molecules, forming an unusual three-dimensional coordination polymer.

  13. Redetermination of [Pr(NO33(H2O4]·2H2O

    Directory of Open Access Journals (Sweden)

    Roel Decadt

    2012-07-01

    Full Text Available The structure of the title compound, tetraaquatris(nitrato-κ2O,O′praseodymium(III dihydrate, was redetermined. The structure models derived from the previous determinations [Rumanova et al. (1964. Kristallografiya, 9, 642–654; Fuller & Jacobson (1976. Cryst. Struct. Commun. 5, 349–352] were confirmed, but now with all H atoms unambiguously located, revealing a complex O—H...O hydrogen-bonding network, extending throughout the whole structure. In the title compound, the coordination environment of the PrIII atom can best be described as a distorted bicapped square antiprism defined by three bidentate nitrate anions and four water molecules. Additionally, two lattice water molecules are observed in the crystal packing. The title compound is isotypic with several other lanthanide-containing nitrate analogues.

  14. CRYSTAL STRUCTURE OF (Cy2NH22MoO4.2H2O

    Directory of Open Access Journals (Sweden)

    Serigne Fallou Pouye

    2014-05-01

    Full Text Available The structure of this salt consists of a 3D structure. The anion interacts with NH2 group of the cation and H2O molecules respectively through N-H---O and O-H---O hydrogen bonds. The anion MoO42- is almost perfectly tetrahedral. The four values of the lengths of Mo- O bonds are all equal to 1.7613 Å (12.

  15. Exposed H2O-rich areas detected on Ceres with Dawn Visible and Infrared Mapping Spectrometer

    Science.gov (United States)

    Combe, Jean-Philippe; Raponi, Andrea; De Sanctis, Maria Cristina; Tosi, Federico; Ammannito, Eleonora; Byrne, Shane; Giacomo Carrozzo, Filippo; Hayne, Paul O.; Hughson, Kynan Horace; Johnson, Katherine Ellen; Landis, Margaret E.; Mazarico, Erwan; McCord, Thomas B.; Pieters, Carle; Ruesch, Ottaviano; Singh, Sandeep; Raymond, Carol; Russell, Christopher T.; VIR Team

    2016-10-01

    H2O-rich materials are exposed at the surface of Ceres as discovered from VIR spectra [1] of the Dawn mission [2]. Oxo crater exhibits the most diagnostic absorption bands of the H2O molecule at 1.65 and 1.28 µm [3]. These features exist in at least four other locations, and they are consistent with H2O ice mixed with low-albedo components [3,4]. Spectra of mineral hydrates such as salts are also characterized by H2O absorption overtones, however they do not fit VIR observations as well as H2O ice spectra. In order to further constrain the composition, the thermophysical and chemical stability of exposed H2O-rich compounds on Ceres and results from chemical models of Ceres interior are being investigated. One meter of pure H2O ice exposed to direct sunlight would sublimate within a few tens of years [5-7].The sublimation of a H2O ice-cemented regolith would leave a low-albedo lag deposit that would also decrease detectability over time [8]. All the reported H2O exposures occur at latitudes higher than 30°N in fresh craters near rim shadows, have surface area < 3 km2, and relatively high albedo.The exposed H2O ice observed by VIR is likely due to a recent impact or a landslide. In some occurrences, high-albedo materials observed within these shadows by the Framing Camera (FC) are contiguous to the observed H2O several of them could be in Permanently Shadowed Regions. The surface shape model and history of illumination will allow us to determine whether these areas could be cold traps where H2O ice could be preserved from sublimation [9].AcknowledgementsThe funding for this research was provided under the NASA Dawn mission through a subcontract 2090-S-MB516 from the University of California, Los Angeles and the Dawn Guest Investigator Program. The VIR instrument and VIR team are funded by ASI (Italian Space Agency) and INAF (Istituto Nazionale di Astrofisica).References1. De Sanctis M.C. et al.,2011, SSR 1632. Russell C. T. et al., 2011, SSR 1633. Combe J-Ph. et al

  16. Low energy spin dynamics of a quantum ferrimagnetic chain, NiCu(pba)(H 2O) 32H 2O

    Science.gov (United States)

    Fujiwara, N.; Hagiwara, M.

    2000-01-01

    Nuclear magnetic resonance (NMR) for 1H nuclei was performed in a Heisenberg chain with alternating spins S=1 and 1/2, NiCu(pba)(H 2O) 32H 2O (pba=1,3-propylenebis (oxamato)) from 4.2 to 280 K. The relaxation rate (1/ T1) is proportional to 1/ H ( H is applied field), whereas the temperature dependence is weak and is almost constant at high temperatures. The temperature and field dependences are investigated on the basis of the spin-wave theory.

  17. Bolometric Luminosity Correction of H2O Maser AGNs

    Indian Academy of Sciences (India)

    Q. Guo; J. S. Zhang; J. Wang

    2014-09-01

    For the H2O maser host AGN sample, we derived their bolometric luminosity corrections, based on their X-ray data and [O III] emission line luminosities. Our results for maser AGNs is comparable to that of non-maser AGNs.

  18. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

    2011-01-01

    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...

  19. Odin observations of H2O in the Galactic Centre

    CERN Document Server

    Sandqvist, A; Black, J; Sandqvist, Aa.

    2003-01-01

    The Odin satellite has been used to detect emission and absorption in the 557-GHz H2O line in the Galactic Centre towards the Sgr A* Circumnuclear Disk (CND), and the Sgr A +20 km/s and +50 km/s molecular clouds. Strong broad H2O emission lines have been detected in all three objects. Narrow H2O absorption lines are present at all three positions and originate along the lines of sight in the 3-kpc Spiral Arm, the -30 km/s Spiral Arm and the Local Sgr Spiral Arm. Broad H2O absorption lines near -130 km/s are also observed, originating in the Expanding Molecular Ring. A new molecular feature (the ``High Positive Velocity Gas'' - HPVG) has been identified in the positive velocity range of ~ +120 to +220 km/s, seen definitely in absorption against the stronger dust continuum emission from the +20 km/s and +50 km/s clouds and possibly in emission towards the position of Sgr A* CND. The 548-GHz H2_18O isotope line towards the CND is not detected at the 0.02 K (rms) level.

  20. Reaction of ferric leghemoglobin with H2O2

    DEFF Research Database (Denmark)

    Moreau, S; Davies, M J; Puppo, A

    1995-01-01

    Ferric leghemoglobin in the presence of H2O2 is known to give rise to protein radicals, at least one of which is centred on a tyrosine residue. These radicals are quenched by at least two processes. The first one involves an intramolecular heme-protein cross-link probably involving the tyrosine...

  1. Self-assembly of a Co(II) dimer through H-bonding of water molecules to a 3D open-framework structure

    Indian Academy of Sciences (India)

    Sujit K Ghosh; Parimal K Bharadwaj

    2005-01-01

    Reaction of pyridine-2,4,6-tricarboxylic acid (ptcH3) with Co(NO3)2.6H2O in presence of 4,4'-bipyridine (4,4'-bpy) in water at room temperature results in the formation of {[Co2(ptcH)2(4,4'-bpy)(H2O)4].2H2O}, (1). The solid-state structure reveals that the compound is a dimeric Co(II) complex assembled to a 3D architecture via an intricate intra- and inter-molecular hydrogen-bonding interactions involving water molecules and carboxylate oxygens of the ligand ptcH2-. Crystal data: monoclinic, space group 21/, = 11.441(5) Å, = 20.212(2) Å, = 7.020(5) Å, = 103.77(5)°, = 1576.7(1) Å3, = 2, 1 = 0.0363, 2 = 0.0856, = 1.000.

  2. Kinetic Model for UV/H2O2 Degradation of 5-Methoxypsoralen

    Science.gov (United States)

    Tchaikovskaya, O. N.; Bryantseva, N. G.; Carrasco, J. L. Gómez; Krayukhina, V. S.; Almagro, M. D. Murcia; Gómez, M. Gómez

    2016-08-01

    The influence of H2O2 on the photodegradataion of 5-methoxypsoralen (5-MOP) in ethanol and in waterethanol solutions upon exposure to KrCl excilamp radiation (λrad = 222 nm) and XeBr excilamp radiation (λrad = 283 nm) is investigated. A kinematic model of photodegradation of the investigated molecule is constructed. The addition of H2O2 resulted in a weak increase of the decay rate of 5-MOP in ethanol exposed to KrCl excilamp radiation. In water-ethanol solutions the addition of H2O2 altered the mechanism of decay of 5-MOP irradiated by the KrCl excilamp in comparison with irradiation by the XeBr excilamp. It has been shown that upon exposure to XeBr excilamp radiation in the presence of H2O2, the primary photoproduct of the transformation of 5-MOP in the reaction corresponding to the first-order kinetic model is formed both in ethanol and in the water-ethanol solutions. Maximum removal of 5-MOP takes place for the ratio of initial concentrations [5-MOP]:[H2O2] = 1:3 after 60 min irradiation. It is found that irradiation by the XeBr excilamp the decay rate of 5-MOP is 5 times higher in the water-ethanol solutions in comparison with ethanol. Upon exposure to KrCl excilamp radiation the mechanism of 5-MOP decay corresponds to a pseudo-firstorder kinetic model. The nature of the dependence of the decay rate of 5-MOP on the irradiation time for the ratio of initial concentrations [5-MOP]:[H2O2] = 1:24 indicates that during decay of the initial compound a photoproduct appears in the system which decays during the irradiation time into secondary compounds. Efficient removal of 5-MOP under this irradiation takes place for the ratio of initial concentrations [5-MOP]:[H2O2] = 1:10 after 60 min irradiation.

  3. Tricyclic sesquiterpene copaene prevents H2O2-induced neurotoxicity

    Directory of Open Access Journals (Sweden)

    Hasan Turkez

    2014-02-01

    Full Text Available Aim: Copaene (COP, a tricyclic sesquiterpene, is present in several essential oils of medicinal and aromatic plants and has antioxidant and anticarcinogenic features. But, very little information is known about the effects of COP on oxidative stress induced neurotoxicity. Method: We used hydrogen peroxide (H2O2 exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of COP in H2O2-induced toxicity in rat cerebral cortex cell cultures for the first time. For this purpose, methyl thiazolyl tetrazolium (MTT and lactate dehydrogenase (LDH release assays were carried out to evaluate cytotoxicity. Total antioxidant capacity (TAC and total oxidative stress (TOS parameters were used to evaluate oxidative changes. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG levels, the single cell gel electrophoresis (SCGE or comet assay was also performed for measuring the resistance of neuronal DNA to H2O2-induced challenge. Result: The results of this study showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage increased in the H2O2 alone treated cultures. But pre-treatment of COP suppressed the cytotoxicity, genotoxicity and oxidative stress which were increased by H2O2. Conclusion: It is proposed that COP as a natural product with an antioxidant capacity in mitigating oxidative injuries in the field of neurodegenerative diseases. [J Intercult Ethnopharmacol 2014; 3(1.000: 21-28

  4. Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).

    Science.gov (United States)

    Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min

    2014-08-30

    The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems.

  5. Structure of trihydrated rare-earth acid diphosphates LnHP 2O 7·3H 2O ( Ln=La, Er)

    Science.gov (United States)

    Ben Moussa, S.; Ventemillas, S.; Cabeza, A.; Gutierrez-Puebla, E.; Sanz, J.

    2004-06-01

    In trihydrated lanthanum acid-diphosphates LnHP 2O 7·3H 2O, prepared from acid LnCl 3 and Na 4P 2O 7 solutions (pH=1), two crystal forms were obtained. Layered structures of two representative members of this family have been determined by single-crystal X-ray diffraction (XRD) technique. In the case of orthorhombic LaHP 2O 7·3H 2O (type I), lanthanum cations are ninefold coordinated and diphosphate groups adopt a staggered (alternated) configuration. In the case of triclinic ErHP 2O 7·3H 2O (type II), erbium cations are eightfold coordinated and diphosphate groups adopt an eclipsed configuration. In agreement with Infrared (IR) spectroscopic data, a bended configuration for diphosphate groups has been deduced. In both structures, one-dimensional chains of edge-sharing rare-earth polyhedra are linked together by diphosphate groups to form the phosphate layers. In both diphosphates, PO 4 and HPO 4 environments have been identified by 31P MAS-NMR technique. In the two compounds, OH groups of HPO 4 tetrahedra point out of diphosphate planes interacting with adjacent layers. In La-diphosphate, the interaction between HPO 4 groups and water molecules of adjacent layers is favored; however, in Er-diphosphate, the interaction between phosphate acid groups of contiguous layers is produced. Based on structural information deduced, differences detected in IR and NMR spectra of two disphosphates are discussed.

  6. Stabilization of noncondensed (As(III)S3)(3-) anions by coordinating to [Mn(II)(phen)](2+) complex cations: a mixed-valent thioarsenate (III, V) {[Mn(phen)]3(As(V)S4)(As(III)S3)}(n)·nH2O showing the coexistence of antiferromagnetic order, photoluminescence, and nonlinear optical properties.

    Science.gov (United States)

    Liu, Guang-Ning; Jiang, Xiao-Ming; Wu, Mei-Feng; Wang, Guan-E; Guo, Guo-Cong; Huang, Jin-Shun

    2011-06-20

    A novel one-dimensional (1-D) mixed-valent thioarsenate (III, V), {[Mn(phen)](3)(As(V)S(4))(As(III)S(3))}(n)·nH(2)O (1), with a noncentrosymmetric (NCS) polar packing arrangement has been obtained under solvothermal conditions. The noncondensed (As(III)S(3))(3-) anion in 1 is stabilized by coordinating to [Mn(II)(phen)](2+) complex cations and exhibits an unprecedented μ(3)-1,2κS:2,3κS':3κS'' linkage mode. Compound 1 represents the first example of the stabilization of noncondensed (MQ(3))(3-) (M = As, Sb; Q = S, Se) species only in the coordination of TM(II) complex cations (TM = transition-metal) and the first observation of the coexistence of the (As(V)S(4))(3-) tetrahedron and the noncondensed (As(III)S(3))(3-) pyramid in a single compound. Of particular interest, compound 1 is also an antiferromagnet with T(N) = 31 K, and exhibits photoluminescence (PL) with a maximum emission at about 438 nm and a second harmonic generation (SHG) response.

  7. A Herschel/HIFI Legacy Survey of HF and H2O in the Galaxy: Probing Diffuse Molecular Cloud Chemistry

    CERN Document Server

    Sonnentrucker, P; Neufeld, D A; Flagey, N; Gerin, M; Goldsmith, P; Lis, D; Monje, R

    2015-01-01

    We combine Herschel observations of a total of 12 sources to construct the most uniform survey of HF and H2O in our Galactic disk. Both molecules are detected in absorption along all sight lines. The high spectral resolution of the Heterodyne Instrument for the Far-Infrared (HIFI) allows us to compare the HF and H2O distributions in 47 diffuse cloud components sampling the disk. We find that the HF and H2O velocity distributions follow each other almost perfectly and establish that HF and H2O probe the same gas-phase volume. Our observations corroborate theoretical predictions that HF is a sensitive tracer of H2 in diffuse clouds, down to molecular fractions of only a few percent. Using HF to trace H2 in our sample, we find that the N(H2O)-to-N(HF) ratio shows a narrow distribution with a median value of 1.51. Our results further suggest that H2O might be used as a tracer of H2 -within a factor 2.5- in the diffuse interstellar medium. We show that the measured factor of ~2.5 variation around the median is dri...

  8. Laboratory Infrared Spectra of Polycyclic Aromatic Nitrogen Heterocycles: Quinoline, and Phenanthridine in Solid Argon and H2O

    Science.gov (United States)

    Bernstein, M. P.; Mattioda, A. L.; Sandford, S. A.; Hudgins, D. M.

    2004-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are common throughout the universe. Their detection and identification are based on telescopic infrared (IR) spectra compared with laboratory data. Polycyclic Aromatic Nitrogen Heterocycles (PANHs) are heterocyclic aromatics i.e., PAHs with carbon atoms replaced by a nitrogen atom. These molecules should be present in the interstellar medium, but have received relatively little attention. We present mid-IR spectra of two PANHs, quinoline (C9H7N), and phenanthridine (C13H9N) isolated in solid argon and frozen in solid H2O at 12 K, conditions yielding data directly comparable to astronomical observations. In contrast to simple PAHs, that do not interact strongly with solid H2O, the nitrogen atoms in PANHs are potentially capable of hydrogen bonding with H2O. Whereas the IR spectrum of phenanthridine in H2O is similar to that of the same compound isolated in an argon matrix, quinoline absorptions shift up to 16 cm(sup -1) (0.072 mm) between argon and H2O. Thus, astronomers will not always be able to rely on IR band positions of matrix isolated PANHs to correctly interpret the absorptions of PANHs frozen in H2O ice grains. Furthermore, our data suggest that relative band areas also vary, so determining column densities to better than a factor of 3 will require knowledge of the matrix in which the PANH is embedded and laboratory studies of relevant samples.

  9. Structure of [M + H - H(2)O](+) from protonated tetraglycine revealed by tandem mass spectrometry and IRMPD spectroscopy.

    Science.gov (United States)

    Bythell, Benjamin J; Dain, Ryan P; Curtice, Stephanie S; Oomens, Jos; Steill, Jeffrey D; Groenewold, Gary S; Paizs, Béla; Van Stipdonk, Michael J

    2010-04-22

    Multiple-stage tandem mass spectrometry and collision-induced dissociation were used to investigate loss of H(2)O or CH(3)OH from protonated versions of GGGX (where X = G, A, and V), GGGGG, and the methyl esters of these peptides. In addition, wavelength-selective infrared multiple photon dissociation was used to characterize the [M + H - H(2)O](+) product derived from protonated GGGG and the major MS(3) fragment, [M + H - H(2)O - 29](+) of this peak. Consistent with the earlier work [ Ballard , K. D. ; Gaskell , S. J. J. Am. Soc. Mass Spectrom. 1993 , 4 , 477 - 481 ; Reid , G. E. ; Simpson , R. J. ; O'Hair , R. A. J. Int. J. Mass Spectrom. 1999 , 190/191 , 209 -230 ], CID experiments show that [M + H - H(2)O](+) is the dominant peak generated from both protonated GGGG and protonated GGGG-OMe. This strongly suggests that the loss of the H(2)O molecule occurs from a position other than the C-terminal free acid and that the product does not correspond to formation of the b(4) ion. Subsequent CID of [M + H - H(2)O](+) supports this proposal by resulting in a major product that is 29 mass units less than the precursor ion. This is consistent with loss of HN horizontal lineCH(2) rather than loss of carbon monoxide (28 mass units), which is characteristic of oxazolone-type b(n) ions. Comparison between experimental and theoretical infrared spectra for a group of possible structures confirms that the [M + H - H(2)O](+) peak is not a substituted oxazolone but instead suggests formation of an ion that features a five-membered ring along the peptide backbone, close to the amino terminus. Additionally, transition structure calculations and comparison of theoretical and experimental spectra of the [M + H - H(2)O - 29](+) peak also support this proposal.

  10. Synthesis and Crystal Structure of [NiL2(H2O)2](ClO4)2L=MBPT=4-p-methylphenyl-3,5-bis-(pyridin-2-yl)-1,2,4-triazole

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Nickel (II) complex, [Ni(MBPT)2(H2O)2](ClO4)2 (MBPT=4-p-methylphenyl-3,5-bis-(pyridin-2-yl)-1,2,4-triazole), was synthesized and its crystal structure determined by X-ray diffraction methods.The complex adopts a distorted octahedral environment made up of two bidentate chelating MBPT ligands in the equatorial plane and two water molecules filling the axial positions.

  11. Optimization of H2O2 dosage in microwave-H2O2 process for sludge pretreatment with uniform design method

    Institute of Scientific and Technical Information of China (English)

    Qingcong Xiao; Hong Yan; Yuansong Wei; Yawei Wang; Fangang Zeng; Xiang Zheng

    2012-01-01

    A microwave-H2O2 process for sludge pretreatment exhibited high efficiencies of releasing organics,nitrogen,and phosphorus,but large quantities of H2O2 residues were detected.A uniform design method was thus employed in this study to further optimize H2O2 dosage by investigating effects of pH and H2O2 dosage on the amount of H2O2 residue and releases of organics,nitrogen,and phosphorus.A regression model was established with pH and H2O2 dosage as the independent variables,and H2O2 residue and releases of organics,nitrogen,and phosphorus as the dependent variables.In the optimized microwave-H2O2 process,the pH value of the sludge was firstly adjusted to 11.0,then the sludge was heated to 80C and H2O2 was dosed at a H2O2:mixed liquor suspended solids (MLSS) ratio of 0.2,and the sludge was finally heated to 100℃ by microwave irradiation.Compared to the microwave-H2O2 process without optimization,the H2O2 dosage and the utilization rate of H2O2 in the optimized microwave-H2O2 process were reduced by 80% and greatly improved by 3.87 times,respectively,when the H2O2:MLSS dosage ratio was decreased from 1.0 to 0.2,resulting in nearly the same release rate of soluble chemical oxygen demand in the microwave-H2O2 process without optimization at H2O2:MLSS ratio of 0.5.

  12. Crystal structure of [NaZn(BTC)(H2O)4]·1.5H2O (BTC = benzene-1,3,5-tri-carb-oxy-l-ate): a heterometallic coordination compound.

    Science.gov (United States)

    Ni, Min; Li, Quanle; Chen, Hao; Li, Shengqing

    2015-07-01

    The title coordination polymer, poly[[μ-aqua-tri-aqua-(μ3-benzene-1,3,5-tri-carboxyl-ato)sodiumzinc] sesquihydrate], {[NaZn(C9H3O6)(H2O)4]·1.5H2O} n , was obtained in ionic liquid microemulsion at room temperture by the reaction of benzene-1,3,5-tri-carb-oxy-lic acid (H3BTC) with Zn(NO3)2·6H2O in the presence of NaOH. The asymmetric unit comprises two Na(+) ions (each located on an inversion centre), one Zn(2+) ion, one BTC ligand, four coordinating water mol-ecules and two solvent water molecules, one of which is disordered about an inversion centre and shows half-occupation. The Zn(2+) cation is five-coordinated by two carboxyl-ate O atoms from two different BTC ligands and three coordinating H2O mol-ecules; the Zn-O bond lengths are in the range 1.975 (2)-2.058 (3) Å. The Na(+) cations are six-coordinated but have different arrangements of the ligands: one is bound to two carboxyl-ate O atoms of two BTC ligands and four O atoms from four coordinating H2O mol-ecules while the other is bound by four carboxyl-ate O atoms from four BTC linkers and two O atoms of coordinating H2O mol-ecules. The completely deprotonated BTC ligand acts as a bridging ligand binding the Zn(2+) atom and Na(+) ions, forming a layered structure extending parallel to (100). An intricate network of O-H⋯O hydrogen bonds is present within and between the layers.

  13. Preparation and H2O2 oxidation of extract

    Institute of Scientific and Technical Information of China (English)

    Tian Yujiao; Qin Zhihong; Li Baomin

    2012-01-01

    Tongting coal (TTC) was exhaustively extracted with carbon disulfide and/N/-melthy-2-pyrolidinone (CS2/NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% Ad and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H2O2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer (GC/MS).The results show that extract is more reactive with H2O2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.

  14. Synthesis and Crystal Structure of [Cu(phen)2(SO4)(H2O)]·0.5C4H4O4·7H2O

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Qin; WEN Yi-Hang; KANG Yao; ZHANG Jian; CHENG Jian-Kai; LI Zhao-Ji; YAO Yuan-Gen

    2006-01-01

    The title compound, [Cu(phen)2(SO4)(H2O)]·0.5C4H4O4·7H2O (phen = 1,10-phe-nanthroline and C4H4O4 = fumaric acid), has been synthesized and characterized by single-crystal X-ray diffraction. The crystal is of triclinic, space group P with a = 11.4827(2), b = 11.9086(2), c = 13.77350(10)(A), α = 80.6830(10), β = 66.6480(10), γ = 64.0480(10)o, V = 1554.63(4) (A)3, Mr = 722.17, Z = 2, Dc = 1.543 g/cm3, μ = 0.845 mm-1, F(000) = 750, R = 0.0349 and wR = 0.0837 for 4754 observed reflections (I > 2σ(I)). The compound contains a six-coordinated copper(II) center, which is surround by four N atoms of two phen ligands (Cu-N distances in the range of 1.997(2)~2.225(2)(A)), one sulfate O atom (Cu-O = 2.0037(17) (A)) and one water O atom (Cu-O(5w) = 2.719(2) (A)) in a distorted octahedral geometry. Extensive hydrogen-bonding interactions are involved in water molecules, ligated sulfate anions and fumaric acid molecules. In addition, π-π interactions via aromatic nitrogen-containing ligands are also discussed. The combination of non-covalent interactions leads to the formation of a 3-D network structure.

  15. H2O diffusion in Mount Changbai peralkaline rhyolitic melt

    Science.gov (United States)

    Zhang, Y.; Xu, Z.; Wang, H.; Behrens, H.

    2008-05-01

    For quantitative modeling of bubble growth and volcanic eruption dynamics, it is necessary to know H2O diffusivity in the melt. Mount Changbai Volcano at the border of China and North Korea has produced explosive peralkaline rhyolitic eruptions, including a 30-km3 eruption with an age of 1 ky (Horn and Schmincke, 2000). H2O diffusivity is expected to be greater in a peralkaline rhyolitic melt than a calc-alkaline rhyolitic melt. We have experimentally investigated H2O diffusion in Mount Changbai peralkaline rhyolite. Because phenocryst-free glass is not available from Mount Changbai eruption products, the starting materials (nominally dry and hydrous) are synthesized. The diffusion couple technique, with one half dry and the other half wet, is adopted. Three high- temperature experiments have been carried out at 500 MPa and one at 1500 MPa in a piston-cylinder apparatus. After the experiment, the sample is prepared into a doubly-polished section of about 0.2 mm thickness, which is analyzed by a Perkin-Elmer FTIR microscope. The data are fit following the procedures of Zhang and Behrens (2000) and Ni and Zhang (2008). Preliminary data show that H2O diffusivity in peralkaline rhyolitic melt is greater than that in calc-alkaline rhyolitic melt (Zhang and Behrens, 2000), as expected. The exact difference depends on temperature and pressure, and the ratio of diffusivity in the peralkaline rhyolitic melt to that in the calc-alkaline rhyolitic melt ranges from 1 to 3. More experiments will be conducted on this melt to provide the basic data for specific modeling of bubble growth and volcanic eruption dynamics in past and future Mount Changbai eruptions and other peralkaline rhyolitic eruptions. References: Horn S and Schmincke H U (2000) Bull. Volcanol., 61, 537. Ni H and Zhang Y (2008) Chem. Geol., doi: 10.1016/j.chemgeo.2008.01.011. Zhang Y and Behrens H (2000) Chem. Geol., 169, 243.

  16. Constraints on the H2O formation mechanism in the wind of carbon-rich AGB stars

    Science.gov (United States)

    Lombaert, R.; Decin, L.; Royer, P.; de Koter, A.; Cox, N. L. J.; González-Alfonso, E.; Neufeld, D.; De Ridder, J.; Agúndez, M.; Blommaert, J. A. D. L.; Khouri, T.; Groenewegen, M. A. T.; Kerschbaum, F.; Cernicharo, J.; Vandenbussche, B.; Waelkens, C.

    2016-04-01

    Context. The recent detection of warm H2O vapor emission from the outflows of carbon-rich asymptotic giant branch (AGB) stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H2O vapor formation. In the first, periodic shocks passing through the medium immediately above the stellar surface lead to H2O formation. In the second, penetration of ultraviolet interstellar radiation through a clumpy circumstellar medium leads to the formation of H2O molecules in the intermediate wind. Aims: We aim to determine the properties of H2O emission for a sample of 18 carbon-rich AGB stars and subsequently constrain which of the above mechanisms provides the most likely warm H2O formation pathway. Methods: Using far-infrared spectra taken with the PACS instrument onboard the Herschel telescope, we combined two methods to identify H2O emission trends and interpreted these in terms of theoretically expected patterns in the H2O abundance. Through the use of line-strength ratios, we analyzed the correlation between the strength of H2O emission and the mass-loss rate of the objects, as well as the radial dependence of the H2O abundance in the circumstellar outflow per individual source. We computed a model grid to account for radiative-transfer effects in the line strengths. Results: We detect warm H2O emission close to or inside the wind acceleration zone of all sample stars, irrespective of their stellar or circumstellar properties. The predicted H2O abundances in carbon-rich environments are in the range of 10-6 up to 10-4 for Miras and semiregular-a objects, and cluster around 10-6 for semiregular-b objects. These predictions are up to three orders of magnitude greater than what is predicted by state-of-the-art chemical models. We find a negative correlation between the H2O/CO line-strength ratio and gas mass-loss rate for Ṁg> 5 × 10-7 M⊙ yr-1, regardless of the upper-level energy of the relevant transitions

  17. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex [La(betaine)2(H2O)6Fe(CN)6]·2H2O

    Institute of Scientific and Technical Information of China (English)

    LIANG Shu-Hui; CHE Yun-Xia; ZHENG Ji-Min

    2005-01-01

    The title complex [La(betaine)2(H2O)6Fe(CN)6](2H2O (betaine = (CH3)3NCH2CO2) has been synthesized and characterized by X-ray single-crystal structure analysis. The crystal crystallizes in monoclinic, space group P21/n with a = 15.793(5), b = 8.927(3), c = 22.257(7) (A), β = 110.147(5)°, C16H38FeLaN8O12, Mr = 729.31, Z = 4, V = 2946.0(15) (A)3, Dc = 1.640 g/m3, μ(MoKα) = 1.988 mm-1, F(000) =1476, R = 0.0388 and wR = 0.0827 for 4237 observed reflections (I > 2σ(I)). The La3+ ion is nine-coordinated by one cyano nitrogen atom and eight oxygen atoms of two betaine and six water molecules. Each complex molecule is connected to form a 3D network structure by some O-H…O and O-H…N hydrogen bonds.

  18. Solar kerosene from H2O and CO2

    Science.gov (United States)

    Furler, P.; Marxer, D.; Scheffe, J.; Reinalda, D.; Geerlings, H.; Falter, C.; Batteiger, V.; Sizmann, A.; Steinfeld, A.

    2017-06-01

    The entire production chain for renewable kerosene obtained directly from sunlight, H2O, and CO2 is experimentally demonstrated. The key component of the production process is a high-temperature solar reactor containing a reticulated porous ceramic (RPC) structure made of ceria, which enables the splitting of H2O and CO2 via a 2-step thermochemical redox cycle. In the 1st reduction step, ceria is endo-thermally reduced using concentrated solar radiation as the energy source of process heat. In the 2nd oxidation step, nonstoichiometric ceria reacts with H2O and CO2 to form H2 and CO - syngas - which is finally converted into kerosene by the Fischer-Tropsch process. The RPC featured dual-scale porosity for enhanced heat and mass transfer: mm-size pores for volumetric radiation absorption during the reduction step and μm-size pores within its struts for fast kinetics during the oxidation step. We report on the engineering design of the solar reactor and the experimental demonstration of over 290 consecutive redox cycles for producing high-quality syngas suitable for the processing of liquid hydrocarbon fuels.

  19. Interstellar H$_2$O Masers from J Shocks

    CERN Document Server

    Hollenbach, David; McKee, Christopher F

    2013-01-01

    We present a model in which the 22 GHz H$_2$O masers observed in star-forming regions occur behind shocks propagating in dense regions (preshock density $n_0 \\sim 10^6 - 10^8$ cm$^{-3}$). We focus on high-velocity ($v_s > 30$ km s$^{-1}$) dissociative J shocks in which the heat of H$_2$ re-formation maintains a large column of $\\sim 300-400$ K gas; at these temperatures the chemistry drives a considerable fraction of the oxygen not in CO to form H$_2$O. The H$_2$O column densities, the hydrogen densities, and the warm temperatures produced by these shocks are sufficiently high to enable powerful maser action. The observed brightness temperatures (generally $\\sim 10^{11} - 10^{14}$ K) are the result of coherent velocity regions that have dimensions in the shock plane that are 10 to 100 times the shock thickness of $\\sim 10^{13}$ cm. The masers are therefore beamed towards the observer, who typically views the shock "edge-on", or perpendicular to the shock velocity; the brightest masers are then observed with t...

  20. Non-equilibrium radiation of water vapor and retrieval of H2O in the mesosphere and lower thermosphere.

    Science.gov (United States)

    Manuilova, Rada; Feofilov, Artem; Kutepov, Alexander; Yankovsky, Valentine

    2015-04-01

    In the study the modern investigations of vibrational kinetics of H2O molecule in the middle atmosphere and development of the models of non-equilibrium radiation of water vapor in the IR ro-vibrational bands are discussed. Our model accounts for 13 excited vibrational states up to energies 7445 1/cm. In this model, 54 vibrational-translational (V-T) and vibrational-vibrational (V-V) processes of energy exchange at collisions of H2O with N2, O2 and O, which are important at the atmospheric conditions, were taken into account. Different variants of possible values of the rate constants of non-elastic collisional processes were analyzed considering the experimental data. Our consideration of the source of excitation of the first vibrational level H2O(010) due to quasiresonance energy transfer between the first vibrational levels of O2 and H2O molecules is based on the YM-2011 model of electronic-vibrational kinetics of excited products of ozone and oxygen photolysis in the mesosphere and lower thermosphere (MLT). In the model we solved the system of 45 kinetic equations for populations of electronically-vibrationally excited levels of oxygen molecule and excited oxygen atom O(1D). Using the YM-2011 model of electronic-vibrational kinetics of excited products of ozone and oxygen photolysis in the MLT and the model of vibrational kinetics of H2O molecule which has been developed enables us to retrieve altitude profiles of H2O concentrations from the measurements of 6.3 mkm H2O radiance in SABER/TIMED experiment. Currently, the experimental data for the processes of (V-T) and (V-V) energy exchanges occurring at the collisions with atmospheric molecules and atoms are available only for the transitions involving the lowest vibrational levels. In our 14-level model (the upper levels are 002, 101, 200) and in the latest 25-level model, which utilizes 21 levels of the main isotope molecule up to 050, 031, 130, 210 and 012 at 9000 1/cm, and also in all former models, it was

  1. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex[La(DMSO)3(H2O)3Cr(CN)6]·H2O (DMSO = Dimethylsulfoxide) with One-dimensional Chain Molecular Structure

    Institute of Scientific and Technical Information of China (English)

    梁淑惠; 车云霞; 郑吉民

    2004-01-01

    The title complex [La(DMSO)3(H2O)3Cr(CN)6](H2O was obtained by the reaction of LaCl3(7H2O, DMSO and K3[Cr(CN)6] in aqueous solution on a hot water bath. The crystal crystallizes in orthorhombic, space group P212121 with a = 9.827(3), b = 15.037(4), c = 17.633(5)A, C12H26CrLaN6O7S3, Mr = 653.48, Z = 4, V = 2605.7(13) A3, Dc = 1.666 g/m3, μ (MoKα) = 2.314 mm-1, F(000) = 1300, R = 0.0205 and wR = 0.0481 for 5038 observed reflections (I > 2σ(I)). La3+ ion is eight-coordinated by three DMSO molecules, three H2O molecules and two [Cr(CN)6]3- units. The structure of the title complex possesses a cyano-bridged onedimensional zigzag chain structure with alternating La(DMSO)3(H2O)3 and Cr(CN)6 moieties, which are linked by some hydrogen bonds to form a 3D network structure.

  2. Absolute Line Intensities for the nu6 Band of H2O2.

    Science.gov (United States)

    Klee; Winnewisser; Perrin; Flaud

    1999-05-01

    The purpose of this work was to obtain reliable absolute intensities for the nu6 band of H2O2. It was undertaken because strong discrepancies exist between the different nu6 band intensities which are presently available in the literature (A. Perrin, A. Valentin, J.-M. Flaud, C. Camy-Peyret, L. Schriver, A. Schriver, and P. Arcas, J. Mol. Spectrosc. 1995. 171, 358), (R. May, J. Quant. Radiat. Transfer 1991. 45, 267), and (R. L. Sams, personal communication). The method which was chosen in the present work was to measure simultaneously the far-infrared absorptions and the nu6 absorptions of H2O2. Consequently, Fourier transform spectra of H2O2 were recorded at Giessen in a spectral range (370-1270 cm-1) which covers both the R branch of the torsion-rotation band and the P branch of the nu6 band which appear at low and high wavenumbers, respectively. From the low wavenumber data, the partial pressure of H2O2 present in the cell during the recording of the spectra was determined by calibrating the observed absorptions in the torsion-rotation band with intensities computed using the permanent H2O2 dipole moment measured by Stark effect (A. Perrin, J.-M. Flaud, C. Camy-Peyret, R. Schermaul, M. Winnewisser, J.-Y. Mandin, V. Dana, M. Badaoui, and J. Koput, J. Mol. Spectrosc. 1996. 176, 287-296) and [E. A. Cohen and H. M. Pickett, J. Mol. Spectrosc. 1981. 87, 582-583). In the high frequency range, this value of the partial pressure of H2O2 was used to measure absolute line intensities in the nu6 band. Finally, the line intensities in the nu6 band were fitted using the theoretical methods described in detail in our previous works. Using these new results on line intensities together with the line position parameters that we obtained previously, a new synthetic spectra of the nu6 band was generated, leading to a total band intensity of 0.185 x 10(-16) cm-1/(molecule.cm-2) at 296 K. It has to be pointed out that the new line intensities agree to within the experimental

  3. Phosphorous bonding in PCl3:H2O adducts: A matrix isolation infrared and ab initio computational studies

    Science.gov (United States)

    Joshi, Prasad Ramesh; Ramanathan, N.; Sundararajan, K.; Sankaran, K.

    2017-01-01

    Non-covalent interaction between PCl3 and H2O was studied using matrix isolation infrared spectroscopy and ab initio computations. Computations indicated that the adducts are stabilized through novel P⋯O type phosphorus bonding and conventional Psbnd Cl⋯H type hydrogen bonding interactions, where the former adduct is the global minimum. Experimentally, the P⋯O phosphorus bonded adduct was identified in N2 matrix, which was evidenced from the shifts in the vibrational wavenumbers of the modes involving PCl3 and H2O sub-molecules. Atoms in Molecules and Natural Bond Orbital analyses have been performed to understand the nature of interactions in the phosphorus and hydrogen bonded adducts. Interestingly, experimental evidence for the formation of higher PCl3sbnd H2O adduct was also observed in N2 matrix.

  4. Synthesis and Crystal Structure of [{Cd(hmbdc)(H2O)3}·2H2O]n

    Institute of Scientific and Technical Information of China (English)

    HU Yue-Hua; WANG Yan; WANG Zuo-Wei; LI Yi-Zhi; ZHENG He-Gen

    2007-01-01

    A novel coordination polymer [{Cd(hmbdc)(H2O)3}·2H2O]n (hmbdc=5-hydroxy- isophthalic acid) has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a=9.599(3), b=18.699(5), c=7.557(2) (A), β= 108.198(4)°, V=1288.6(6) (A)3, Z=4, Mr=382.60, Dc=1.972 g/cm3, F(000)=760, μ=1.740, the final R=0.0555 and wR=0.0995 for 1732 observed reflections with Ⅰ > 2σ(Ⅰ). The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework.

  5. A Dramatic Influence of Ti Atom on the Electronic Structures of (Al16Ti)n± (n=0-3) Ionic Clusters and Their Interaction with H2O Molecules%(Al16Ti)n±(n=0-3)离子团簇中Ti原子对电子结构及其与H2O分子相互作用的显著影响

    Institute of Scientific and Technical Information of China (English)

    刘以良; 滑亚文; 蒋刚; 陈军

    2015-01-01

    用密度泛函理论结合全电子自旋极化方法构建并优化出了最稳定的(Al16Ti)n±(n=0-3)离子团簇,研究了其几何结构、稳定性和电子结构.同时研究了水分子在(Al16Ti)n±(n=0-3)离子团簇表面的吸附结构和吸附能.研究结果与纯(Al17)n±(n=0-3)离子团簇的电子结构及其与H2O分子的相互作用规律做了对比.通过电子最高占据轨道和最低空轨道的空间分布,发现大部分的活性电子占据在Ti原子位置,少量电子根据曲率从大到小的顺序依次占据.通过分析最稳定的(Al16TiH2O)n±(n=0-3)吸附化合物的几何结构可以看出,水分子都倾向于吸附在Ti原子上,并且为亲氧吸附.在所有的吸附化合物中,(Al16TiH2O)+具有最短的平均O―H键长,比孤立H2O分子中的O―H键约长0.0003 nm,然后随着电子数的增加或减少, O―H键都会进一步被拉长.研究结果表明, Al团簇离子中Ti原子的掺杂可以有效提高H2O分子的解离效率.另外,在金属团簇的几何结构效应与杂质效应共同出现时,杂质的影响占据了主导地位.%The most stable (Al16Ti)n± (n=0-3) ions were modeled and optimized using density functional theory combined with al-electron spin-polarized calculations. The geometries, stabilities, and electronic structures of the (Al16Ti)n ± (n=0-3) ionic clusters, as wel as the adsorption structures and adsorption energies of H2O molecules on the (Al16Ti)n± (n=0-3) ionic clusters, were studied. The results were compared with those obtained for pure (Al17)n± (n=0-3) ionic clusters. The spatial distributions of the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals for the (Al16Ti)n± (n=0-3) ionic clusters showed that the free electrons tend to occupy Ti sites. And a few residual free electrons would occupy sites with large curvatures. An extensive structure search was performed to identify the low-energy conformations of (Al16TiH2O)n± (n=0-3) complexes

  6. 35Cl NQR study of lattice dynamic and magnetic property of a crystalline coordination polymer {CuCA(phz)(H 2O) 2} n

    Science.gov (United States)

    Gotoh, Kazuma; Terao, Takeshi; Asaji, Tetsuo

    2007-01-01

    Copper(II) compounds {CuCA(phz)(H 2O) 2} n (H 2CA = chloranilic acid, phz = phenazine) having a layer structure of -CuCA(H 2O) 2- polymer chains and phenazine were studied by 35Cl nuclear quadrupole resonance (NQR). The single NQR line observed at 35.635 MHz at 261.5 K increased to 35.918 MHz at 4.2 K. The degree of reduction of electric field gradient due to lattice vibrations was similar to that of chloranilic acid crystal. Temperature dependence of spin-lattice relaxation time, T1, of the 35Cl NQR signal below 20 K, between 20 and 210 K, and above 210 K, was explained by (1) a decrease of effective electron-spin density caused by antiferromagnetic interaction, (2) a magnetic interaction between Cl nuclear-spin and electron-spins on paramagnetic Cu(II) ions, and (3) an increasing contribution from reorientation of ligand molecules, respectively. The electron spin-exchange parameter ∣ J∣ between the neighboring Cu(II) electrons was estimated to be 0.33 cm -1 from the T1 value of the range 20-210 K. Comparing this value with that of J = -1.84 cm -1 estimated from the magnetic susceptibility, it is suggested that the magnetic dipolar coupling with the electron spins on Cu(II) ions must be the principal mechanism for the 35Cl NQR spin-lattice relaxation of {CuCA(phz)(H 2O) 2} n but a delocalization of electron spin over the chloranilate ligand has to be taken into account.

  7. H2O2 mediates the regulation of ABA catabolism and GA biosynthesis in Arabidopsis seed dormancy and germination.

    Science.gov (United States)

    Liu, Yinggao; Ye, Nenghui; Liu, Rui; Chen, Moxian; Zhang, Jianhua

    2010-06-01

    H(2)O(2) is known as a signal molecule in plant cells, but its role in the regulation of aqbscisic acid (ABA) and gibberellic acid (GA) metabolism and hormonal balance is not yet clear. In this study it was found that H(2)O(2) affected the regulation of ABA catabolism and GA biosynthesis during seed imbibition and thus exerted control over seed dormancy and germination. As seen by quantitative RT-PCR (QRT-PCR), H(2)O(2) up-regulated ABA catabolism genes (e.g. CYP707A genes), resulting in a decreased ABA content during imbibition. This action required the participation of nitric oxide (NO), another signal molecule. At the same time, H(2)O(2) also up-regulated GA biosynthesis, as shown by QRT-PCR. When an ABA catabolism mutant, cyp707a2, and an overexpressing plant, CYP707A2-OE, were tested, ABA content was negatively correlated with GA biosynthesis. Exogenously applied GA was able to over-ride the inhibition of germination at low concentrations of ABA, but had no obvious effect when ABA concentrations were high. It is concluded that H(2)O(2) mediates the up-regulation of ABA catabolism, probably through an NO signal, and also promotes GA biosynthesis. High concentrations of ABA inhibit GA biosynthesis but a balance of these two hormones can jointly control the dormancy and germination of Arabidopsis seeds.

  8. Assembly of a New Cyano-bridged 4f-3d Dimer Sm(DMSO)4-(H2O)3Cr(CN)6 and Crystal Structure of [K3(18-crown-6)3-(H2O)4] Cr(CN)6 ·3H2O

    Institute of Scientific and Technical Information of China (English)

    周北川; 王宏根; 等

    2003-01-01

    A new syano-bridged binuclear 4f-3d complex Sm(DMSO)4-(H2O)3Cr(CN)6 was synthesized and characterized by single crystal structure analysis.It crystallizes in monoclinic,space group P21 with a=0.9367(3)°and Z=2,In this binuclear complex,Sm atom is eight coordinated and linked to the Cr atom by a cyano bridge,The molecules packs to form 3D structure due to the hydrogen bonds among them. [K3(18-crown-6)3-(H2O)4] Cr(CN)6 ·3H2O(18-C-6 represents 18-crown-6-ether)that was synthesized as a byproduct in the preparation of a Gd-Cr complex is also structurally characterized.Crystal data:triclinic,space group p-1 with a=1.0496(7)nm,b=1.1567(14)nm,c=1.3530(13)nm,α=94.15(9)°,β=96.04(8)°,γ=95.25(9)° and Z=1, [K3(18-crown-6)3-(H2O)4] Cr(CN)6 ·3H2O consists of ionic [K3(18-crown-6)3-(H2O)4]3+ and [Cr(CN)6]3- pairs,of which the [K3(18-C-6)3(H2O)4]3+ ion is a trinuclear cluster connected by water,and K atome are eight coordinated by eight oxygen atoms of one 18-C-6 and two water molecules.

  9. Robertsite, Ca2MnIII3O2(PO43·3H2O

    Directory of Open Access Journals (Sweden)

    Marcelo B. Andrade

    2012-10-01

    Full Text Available Robertsite, ideally Ca2Mn3O2(PO43·3H2O [calcium manganese(III tris(orthophosphate trihydrate], can be associated with the arseniosiderite structural group characterized by the general formula Ca2A3O2(TO43·nH2O, with A = Fe, Mn; T = As, P; and n = 2 or 3. In this study, single-crystal X-ray diffraction data were used to determine the robertsite structure from a twinned crystal from the type locality, the Tip Top mine, Custer County, South Dakota, USA, and to refine anisotropic displacement parameters for all atoms. The general structural feature of robertsite resembles that of the other two members of the arseniosiderite group, the structures of which have previously been reported. It is characterized by sheets of [MnO6] octahedra in the form of nine-membered pseudo-trigonal rings. Located at the center of each nine-membered ring is a PO4 tetrahedron, and the other eight PO4 tetrahedra sandwich the Mn–oxide sheets. The six different Ca2+ ions are seven-coordinated in form of distorted pentagonal bipyramids, [CaO5(H2O2], if Ca—O distances less than 2.85 Å are considered. Along with hydrogen bonding involving the water molecules, they hold the manganese–phosphate sheets together. All nine [MnO6] octahedra are distorted by the Jahn–Teller effect.

  10. Normalized fluctuations, H2O vs n-hexane: Site-correlated percolation

    Science.gov (United States)

    Koga, Yoshikata; Westh, Peter; Sawamura, Seiji; Taniguchi, Yoshihiro

    1996-08-01

    Entropy, volume and the cross fluctuations were normalized to the average volume of a coarse grain with a fixed number of molecules, within which the local and instantaneous value of interest is evaluated. Comparisons were made between liquid H2O and n-hexane in the range from -10 °C to 120 °C and from 0.1 MPa to 500 MPa. The difference between H2O and n-hexane in temperature and pressure dependencies of these normalized fluctuations was explained in terms of the site-correlated percolation theory for H2O. In particular, the temperature increase was confirmed to reduce the hydrogen bond probability, while the pressure appeared to have little effect on the hydrogen bond probability. According to the Le Chatelier principle, however, the putative formation of ``ice-like'' patches at low temperatures due to the site-correlated percolation requirement is retarded by pressure increases. Thus, only in the limited region of low pressure (<300 MPa) and temperature (<60 °C), the fluctuating ice-like patches are considered to persist.

  11. Preparation and Molecular Structure of (SCZ)(TNPG)·2H2O

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-Yan; ZHANG Tong-Lai; ZHANG Jian-Guo

    2005-01-01

    The (SCZ)(TNPG)·2H2O prepared by mixing semicarbazide (SCZ) and trinitrophloroglucinol (TNPG) was characterized by elemental analysis and IR measurement, and its crystal structure was determined by X-ray single-crystal diffraction analysis.The crystal belongs to triclinic,0.93966(19), c = 1.1925(2) nm, α = 67.48(3), β = 77.56(3), γ = 78.93(3)°, V = 0.6908(2) nm3, Z = 2,Dc = 1.789 g/cm3, Mr = 373.23, F(000) = 384, S = 0.999 andt(MoKα) = 0.172 mm-1.The final R and wR are 0.0394 and 0.1057 for 1724 observed reflections with I > 2σ(I).It is concluded that (SCZ)(TNPG) 2H2O is an ionic compound composed of a cation SCZ+, an anion TNPG- and two water molecules.The TNPG anion and SCZ+ cation are bonded together by electrostatic attraction and hydrogen bonds, and the compound structure is stable.The thermal decomposition of (SCZ)(TNPG) 2H2O was studied by using TG-DTG and DSC techniques with a heating rate of 10 ℃/min, showing the compound contains one endothermic process of dehydrating stage and two intensive exothermic decomposition stages.The enthalpy of exothermic decomposition reaction is 452.31 kJ/mol.

  12. Redetermination of [EuCl2(H2O6]Cl

    Directory of Open Access Journals (Sweden)

    Frank Tambornino

    2014-06-01

    Full Text Available The crystal structure of the title compound, hexaaquadichloridoeuropium(III chloride, was redetermined with modern crystallographic methods. In comparison with the previous study [Lepert et al. (1983. Aust. J. Chem. 36, 477–482], it could be shown that the atomic coordinates of some O atoms had been confused and now were corrected. Moreover, it was possible to freely refine the positions of the H atoms and thus to improve the accurracy of the crystal structure. [EuCl2(H2O6]Cl crystallizes with the GdCl3·6H2O structure-type, exhibiting discrete [EuCl2(H2O6]+ cations as the main building blocks. The main blocks are linked with isolated chloride anions via O—H...Cl hydrogen bonds into a three-dimensional framework. The Eu3+ cation is located on a twofold rotation axis and is coordinated in the form of a Cl2O6 square antiprism. One chloride anion coordinates directly to Eu3+, whereas the other chloride anion, situated on a twofold rotation axis, is hydrogen bonded to six octahedrally arranged water molecules.

  13. Syntheses and Structural Researches of Yb3+ Complexes with Nitrilotriacetic Acids—Nine—coordinate K3[Yb(nta)2(H2O)]·5H2O and Eight—coordinate Na3[Yb(nta)2]·6H2O complexes

    Institute of Scientific and Technical Information of China (English)

    WANGJun; ZHANGXiang-dong; JIAWei-guo; LIHui-fang

    2003-01-01

    Yb3+ complexes with two nitrilotriacetic acid molecules were prepared and their compositions were determined as K3[Yb(nta)2(H2O)]·5H2O and Na3[Yb(nta)2]·6H2O by elemental analyses.Their structures were characterized by single-crystal X-ray diffraction analyses.In complex K3[Yb(nta)2(H2O)]·5H2O,the YbN2O7 part forms a nine-coordinate monocapped square antiprismatic structure.In comples Na3[Yb(nta)2]·6H2O,the YbN2O6 part forms an eight-coordinate square antiprismatic structure.It can be seen that the outer cations(K+ and Na+)greatly affect the coordination number and coordinate structure from these results.

  14. Differential stability of the triple helix of (Pro-Pro-Gly)10 in H2O and D2O: thermodynamic and structural explanations.

    Science.gov (United States)

    Gough, C A; Bhatnagar, R S

    1999-12-01

    (Pro-Pro-Gly)10 [(PPG10)], a collagen-like polypeptide, forms a triple-helical, polyproline-II structure in aqueous solution at temperatures somewhat lower than physiological, with a melting temperature of 24.5 degrees C. In this article, we present circular dichroism spectra that demonstrate an increase of the melting temperature with the addition of increasing amounts of D2O to an H2O solution of (PPG)10, with the melting temperature reaching 40 degrees C in pure D2O. A thermodynamic analysis of the data demonstrates that this result is due to an increasing enthalpy of unfolding in D2O vs. H2O. To provide a theoretical explanation for this result, we have used a model for hydration of (PPG)10 that we developed previously, in which inter-chain water bridges are formed between sterically crowded waters and peptide bond carbonyls. Energy minimizations were performed upon this model using hydrogen bond parameters for water, and altered hydrogen bond parameters that reproduced the differences in carbonyl oxygen-water oxygen distances found in small-molecule crystal structures containing oxygen-oxygen hydrogen bonds between organic molecules and H2O or D2O. It was found that using hydrogen bond parameters that reproduced the distance typical of hydrogen bonds to D2O resulted in a significant lowering of the potential energy of hydrated (PPG)10. This lowering of the energy involved energetic terms that were only indirectly related to the altered hydrogen bond parameters, and were therefore not artifactual; the intra-(PPG10) energy, plus the water-(PPG10) van der Waals energy (not including hydrogen bond interactions), were lowered enough to qualitatively account for the lower enthalpy of the triple-helical conformation, relative to the unfolded state, in D2O vs. H2O. This result indicates that the geometry of the carbonyl-D2O hydrogen bonds allows formation of good hydrogen bonds without making as much of an energetic sacrifice from other factors as in the case of

  15. Spectroscopic and theoretical analysis of Pd2+-Cl--H2O system

    Science.gov (United States)

    Podborska, Agnieszka; Wojnicki, Marek

    2017-01-01

    Time dependent density functional theory (TD-DFT) and spectrophotometric methods were used for speciation analysis in Pd2+-Cl--H2O system. It was shown, that there is an excellent harmony between TD-DFT calculated UV-VIS spectra end those registered using spectrophotometric method. It was shown, that for simple electrolyte, a several different form of Pd(II) appears simultaneously. Thanks to TD-DFT method, it was possible to deconvolution experimental UV-VIS spectrum and determination which form of Pd(II) complexes are present in the solution.

  16. Reactions of Ferrous Coproheme Decarboxylase (HemQ) with O2 and H2O2 Yield Ferric Heme b.

    Science.gov (United States)

    Streit, Bennett R; Celis, Arianna I; Shisler, Krista; Rodgers, Kenton R; Lukat-Rodgers, Gudrun S; DuBois, Jennifer L

    2017-01-10

    A recently discovered pathway for the biosynthesis of heme b ends in an unusual reaction catalyzed by coproheme decarboxylase (HemQ), where the Fe(II)-containing coproheme acts as both substrate and cofactor. Because both O2 and H2O2 are available as cellular oxidants, pathways for the reaction involving either can be proposed. Analysis of reaction kinetics and products showed that, under aerobic conditions, the ferrous coproheme-decarboxylase complex is rapidly and selectively oxidized by O2 to the ferric state. The subsequent second-order reaction between the ferric complex and H2O2 is slow, pH-dependent, and further decelerated by D2O2 (average kinetic isotope effect of 2.2). The observation of rapid reactivity with peracetic acid suggested the possible involvement of Compound I (ferryl porphyrin cation radical), consistent with coproheme and harderoheme reduction potentials in the range of heme proteins that heterolytically cleave H2O2. Resonance Raman spectroscopy nonetheless indicated a remarkably weak Fe-His interaction; how the active site structure may support heterolytic H2O2 cleavage is therefore unclear. From a cellular perspective, the use of H2O2 as an oxidant in a catalase-positive organism is intriguing, as is the unusual generation of heme b in the Fe(III) rather than Fe(II) state as the end product of heme synthesis.

  17. Solvothermal Synthesis, Crystal Structure and Electrochemical Property of Complex [Co(p-MBA)2(2,2'-bipy)(H2O)]·(H2O)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    One novel complex [Co(p-MBA)2(2,2'-bipy)(H2O)]·(H2O) has been synthesized by the reaction of p-methylbenzoic acid with 2,2'-bipyridine in the solvent mixture of water and methanol. It crystallizes in triclinic, space group P-1 with a=0.70479(14), b=1.1211(2), c=1.6718(3) nm, α=103.806(3), β=90.795(3), γ=104.207(3)°, V=1.2399(4) nm3, Mr=512.41, Dc=1.373 g/cm3, Z=2, F(000)=532, μ=0.733 mm-1, R=0.0432 and wR=0.0957. The crystal structural analysis shows that the cobalt atom is coordinated with three oxygen atoms from two p-methylbenzoic acids and one water molecule and two nitrogen atoms from one 2,2'-bipyridine,forming a distorted square-pyramidal coordination geometry. The cyclic voltammetry behavior of the complex is also reported.

  18. SYNTHESIS AND STRUCTURE OF A MIXED-LIGANDS COMPLEX [CU(R-LACT)(O-PHEN)(H2O)]•4H2O

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiang; TANG Ding-xing

    2014-01-01

    A mixed-ligands complex with the formula of [Cu(R-lact)(o-phen)(H2O)]•4H2O was synthesized by the reaction of copper carbonate with racemic lactic acid (RS-H2lact), and then with o-phenanthroline(o-phen) in ethanol-water(95%) solution. One of the two obtained com-pounds was dark blue column single crystal and was characterized by elemental analysis, IR spectrum and X-ray single crystal diffraction. The crystal belongs to triclinic system with space group P1, a=7.2825(5) , b=11.7322(8) , c=12.1194(8) , a=65.8280(10)°, β=84.2120(10)°,γ=75.3290(10)°, V=913.88(11) 3, Z=2, Dc=1533kg•m-3, Mr=421.89, μ(MoK\\α)=1.240mm-1,λ=0.71073 , the final R=0.0483 and ωR=0.1199 [I﹥2σ(I)] for 3120 observed reflections, F(000)=438. The copper atom is five coordinated with the distorted square pyramid environment. The five coordinated atoms are two oxygen atoms of depronated hydroxyl group and carboxyl of H2lact, two nitrogen atom of o-phen and one oxygen atom of water molecule.

  19. SO4(=) uptake and catalase role in preconditioning after H2O2-induced oxidative stress in human erythrocytes.

    Science.gov (United States)

    Morabito, Rossana; Remigante, Alessia; Di Pietro, Maria Letizia; Giannetto, Antonino; La Spada, Giuseppina; Marino, Angela

    2017-02-01

    Preconditioning (PC) is an adaptive response to a mild and transient oxidative stress, shown for the first time in myocardial cells and not described in erythrocytes so far. The possible adaptation of human erythrocytes to hydrogen peroxide (H2O2)-induced oxidative stress has been here verified by monitoring one of band 3 protein functions, i.e., Cl(-)/HCO3(-) exchange, through rate constant for SO4(=) uptake measurement. With this aim, erythrocytes were exposed to a mild and transient oxidative stress (30 min to either 10 or 100 μM H2O2), followed by a stronger oxidant condition (300- or, alternatively, 600-μM H2O2 treatment). SO4(=) uptake was measured by a turbidimetric method, and the possible role of catalase (CAT, significantly contributing to the anti-oxidant system in erythrocytes) in PC response has been verified by measuring the rate of H2O2 degradation. The preventive exposure of erythrocytes to 10 μM H2O2, and then to 300 μM H2O2, significantly ameliorated the rate constant for SO4(=) uptake with respect to 300 μM H2O2 alone, showing thus an adaptive response to oxidative stress. Our results show that (i) SO4(=) uptake measurement is a suitable model to monitor the effects of a mild and transient oxidative stress in human erythrocytes, (ii) band 3 protein anion exchange capability is retained after 10 μM H2O2 treatment, (iii) PC response induced by the 10 μM H2O2 pretreatment is clearly detected, and (iv) PC response, elicited by low-concentrated H2O2, is mediated by CAT enzyme and does not involve band 3 protein tyrosine phosphorylation pathways. Erythrocyte adaptation to a short-term oxidative stress may serve as a basis for future studies about the impact of more prolonged oxidative events, often associated to aging, drug consumption, chronic alcoholism, hyperglycemia, or neurodegenerative diseases.

  20. Synthesis and the crystal and molecular structure of the silver(I)-germanium(IV) polymeric complex with citrate anions {[Ag2Ge(H Cit)2(H2O)2] • 2H2O} n

    Science.gov (United States)

    Sergienko, V. S.; Martsinko, E. E.; Seifullina, I. I.; Churakov, A. V.; Chebanenko, E. A.

    2016-03-01

    The synthesis and X-ray diffraction study of compound {[Ag2Ge(H Cit)2(H2O)2] • 2H2O} n , where H4 Cit is the citric acid, are performed. In the polymeric structure, the H Cit 3- ligand fulfils the tetradentate chelate-μ4-bridging (3Ag, Ge) function (tridentate with respect to Ge and Ag atoms). The Ge atom is octahedrally coordinated by six O atoms of two H Cit 3-ligands. The coordination polyhedron of the Ag atom is an irregular five-vertex polyhedron [four O atoms of four H Cit 3- ligands and the O(H2O) atom]. An extended system of O-H···O hydrogen bonds connects complex molecules into a supramolecular 3D-framework.

  1. Switching of the magnetocaloric effect of Mn(II) glycolate by water molecules.

    Science.gov (United States)

    Chen, Yan-Cong; Guo, Fu-Sheng; Liu, Jun-Liang; Leng, Ji-Dong; Vrábel, Peter; Orendáč, Martin; Prokleška, Jan; Sechovský, Vladimír; Tong, Ming-Liang

    2014-03-10

    The transformation of Mn(II) glycolates (glc) between the three-dimensional coordination polymer [Mn(glc)2]n (1) and discrete mononuclear phase [Mn(glc)2 (H2O)2] (2) can be reversibly switched by water molecules, which dramatically change the magnetocaloric effect (MCE) of Mn(II) glycolates from the maximum of 6.9 J kg(-1)  K(-1) in 1 to 60.3 J kg(-1)  K(-1) in 2. This case example reveals that the effect of magnetic coupling on MCE plays a dominant role over that of other factors such as magnetic density for 3d-type magnetic refrigerants.

  2. FTIR spectroscopic studies of the simultaneous condensation of HCl and H2O at 190 K – Atmospheric applications

    Directory of Open Access Journals (Sweden)

    I. Xueref

    2003-01-01

    Full Text Available Type II polar stratospheric cloud particles are made up of ice that forms by water vapor condensation in the presence of numerous trace gases, including HCl. These gaseous species can co-condense with water molecules and perturb ice structure and reactivity. In order to investigate the effect of co-condensing dopants on the structure of ice, we have designed an experimental system where ice films can be stabilized at 190 K, a temperature relevant to the polar stratosphere. We have co-condensed different HCl:H2O gaseous mixtures, with ratios 5:1, 1:10, 1:50 and 1:200 and studied the solids formed by infrared spectroscopy. The IR spectra obtained show that: (1 HCl is likely undergoing ionic dissociation when it is incorporated by co-condensation into the ice at 190 K; (2 this dissociation is done by several water molecules per HCl molecule; and (3 significant differences between our spectra and those of crystalline solids were always detected, and indicated that in all cases the structure of our solids retained some disorganized character. Considering the major impact of HCl on ice structure observed here, and the well known impact of the structure of solids on their reactivity, we conclude that the actual reactivity of stratospheric ice particles, that catalyze reactions involved in ozone depletion, may be different from what has been measured in laboratory experiments that used pure ice.

  3. Proton ordering in tetragonal and monoclinic H2O ice

    CERN Document Server

    Yen, Fei; Berlie, Adam; Liu, Xiaodi; Goncharov, Alexander F

    2015-01-01

    H2O ice remains one of the most enigmatic materials as its phase diagram reveals up to sixteen solid phases. While the crystal structure of these phases has been determined, the phase boundaries and mechanisms of formation of the proton-ordered phases remain unclear. From high precision measurements of the complex dielectric constant, we probe directly the degree of ordering of the protons in H2O tetragonal ice III and monoclinic ice V down to 80 K. A broadened first-order phase transition is found to occur near 202 K we attribute to a quenched disorder of the protons which causes a continuous disordering of the protons during cooling and metastable behavior. At 126 K the protons in ice III become fully ordered, and for the case of ice V becoming fully ordered at 113 K forming ice XIII. Two triple points are proposed to exist: one at 0.35 GPa and 126 K where ices III, IX and V coexist; and another at 0.35 GPa and 113 K where ices V, IX and XIII coexist. Our findings unravel the underlying mechanism driving th...

  4. Experimental evidence of superionic conduction in H2O ice

    Science.gov (United States)

    Sugimura, Emiko; Komabayashi, Tetsuya; Ohta, Kenji; Hirose, Kei; Ohishi, Yasuo; Dubrovinsky, Leonid S.

    2012-11-01

    Ionic conductivity and molar volume measurements were performed on H2O ice at high pressure (P) and temperature (T) in a resistive-heated diamond anvil cell. The conductivity data obtained at P = 20-62 GPa, T = 304-930 K are well fitted with a single Arrhenius equation. Isothermal volume measurements at T = 873 K, P = 30-101 GPa indicate that H2O ice undergoes phase transitions at P = 50 GPa and 53 GPa due to hydrogen-bond symmetrization. Combining these results, we suggest that the conduction mechanism does not change with pressure-induced hydrogen-bond symmetrization. Along the Arrhenius behavior of conductivity data, the experimental evidence for superionic conduction (>10-1 S/cm) was found at T = 739 K, P = 56 GPa and T = 749 K, P = 62 GPa, which is significantly low temperature compared with earlier theoretical estimates resorted to the observation of a drastic rise of the melting curve. We infer that the sudden increase of the melting temperature is not related to the onset of superionic conduction, but is attributed to the phase change regarding to the symmetrization.

  5. The effect of H2O on ice photochemistry

    CERN Document Server

    Oberg, Karin I; Linnartz, Harold; Andersson, Stefan

    2010-01-01

    UV irradiation of simple ices is proposed to efficiently produce complex organic species during star- and planet-formation. Through a series of laboratory experiments, we investigate the effects of the H2O concentration, the dominant ice constituent in space, on the photochemistry of more volatile species, especially CH4, in ice mixtures. In the experiments, thin (~40 ML) ice mixtures, kept at 20-60 K, are irradiated under ultra-high vacuum conditions with a broad-band UV hydrogen discharge lamp. Photodestruction cross sections of volatile species (CH4 and NH3) and production efficiencies of new species (C2H6, C2H4, CO, H2CO, CH3OH, CH3CHO and CH3CH2OH) in water-containing ice mixtures are determined using reflection-absorption infrared spectroscopy during irradiation and during a subsequent slow warm-up. The four major effects of increasing the H2O concentration are 1) an increase of the destruction efficiency of the volatile mixture constituent by up to an order of magnitude due to a reduction of back react...

  6. Infrared absorption of H_2_O toward massive young stars.

    Science.gov (United States)

    van Dishoeck, E. F.; Helmich, F. P.

    1996-11-01

    We present ISO-SWS observations of absorption lines of gas-phase water within its bending vibrational mode at 6μm toward four massive young stars, which cover a range in physical parameters. Hot water with an excitation temperature >200K is detected toward GL 2136 and GL 4176, in addition to GL 2591 discussed by Helmich et al. (1996A&A...315L.173H). The abundance of water with respect to H_2_ is high in these regions, ~(2-3)x10^-5^, and comparable to the solid H_2_O abundance. In contrast, no gas-phase water absorption lines are seen toward NGC 7538 IRS9. The amount of gas-phase water is correlated with the column density of warm gas along the line of sight. Infrared observations of a larger variety of sources may provide insight into the relative importance of evaporation of grain mantles vs. high temperature gas-phase chemistry in producing the observed high abundance of H_2_O.

  7. Putative role of the malate valve enzyme NADP-malate dehydrogenase in H2O2 signalling in Arabidopsis.

    Science.gov (United States)

    Heyno, Eiri; Innocenti, Gilles; Lemaire, Stéphane D; Issakidis-Bourguet, Emmanuelle; Krieger-Liszkay, Anja

    2014-04-19

    In photosynthetic organisms, sudden changes in light intensity perturb the photosynthetic electron flow and lead to an increased production of reactive oxygen species. At the same time, thioredoxins can sense the redox state of the chloroplast. According to our hypothesis, thioredoxins and related thiol reactive molecules downregulate the activity of H2O2-detoxifying enzymes, and thereby allow a transient oxidative burst that triggers the expression of H2O2 responsive genes. It has been shown recently that upon light stress, catalase activity was reversibly inhibited in Chlamydomonas reinhardtii in correlation with a transient increase in the level of H2O2. Here, it is shown that Arabidopsis thaliana mutants lacking the NADP-malate dehydrogenase have lost the reversible inactivation of catalase activity and the increase in H2O2 levels when exposed to high light. The mutants were slightly affected in growth and accumulated higher levels of NADPH in the chloroplast than the wild-type. We propose that the malate valve plays an essential role in the regulation of catalase activity and the accumulation of a H2O2 signal by transmitting the redox state of the chloroplast to other cell compartments.

  8. Photochemistry of HI on argon and water nanoparticles: hydronium radical generation in HI·(H2O)n.

    Science.gov (United States)

    Poterya, Viktoriya; Fedor, Juraj; Pysanenko, Andriy; Tkáč, Ondřej; Lengyel, Jozef; Ončák, Milan; Slavíček, Petr; Fárník, Michal

    2011-02-14

    Photochemistry of HI molecules on large Ar(n) and (H(2)O)(n), n ∼ 100-500, clusters was investigated after excitation with 243 nm and 193 nm laser radiation. The measured H-fragment kinetic energy distributions pointed to a completely different photodissociation mechanism of HI on water than on argon clusters. Distinct features corresponding to the fragment caging (slow fragments) and direct exit (fast fragments) were observed in the spectra from HI photodissociation on Ar(n) clusters. On the other hand, the fast fragments were entirely missing in the spectrum from HI·(H(2)O)(n) and the slow-fragment part of the spectrum had a different shape from HI·Ar(n). The HI·(H(2)O)(n) spectrum was interpreted in terms of the acidic dissociation of HI on (H(2)O)(n) in the ground state, and hydronium radical H(3)O formation following the UV excitation of the ionically dissociated species into states of a charge-transfer-to-solvent character. The H(3)O generation was proved by experiments with deuterated species DI and D(2)O. The experiment was complemented by ab initio calculations of structures and absorption spectra for small HI·(H(2)O)(n) clusters, n = 0-5, supporting the proposed model.

  9. H2O2-induced Leaf Cell Death and the Crosstalk of Reactive Nitric/Oxygen Species([F])

    Institute of Scientific and Technical Information of China (English)

    Yiqin Wang; Aihong Lin; Gary J.Loake; Chengcai Chu

    2013-01-01

    In plants,the chloroplast is the main reactive oxygen species (ROS) producing site under high light stress.Catalase (CAT),which decomposes hydrogen peroxide (H2O2),is one of the controlling enzymes that maintains leaf redox homeostasis.The catalase mutants with reduced leaf catalase activity from different plant species exhibit an H2O2-induced leaf cell death phenotype.This phenotype was differently affected by light intensity or photoperiod,which may be caused by plant species,leaf redox status or growth conditions.In the rice CAT mutant nitric oxide excess 1 (noe1),higher H2O2 levels induced the generation of nitric oxide (NO) and higher S-nitrosothiol (SNO) levels,suggesting that NO acts as an important endogenous mediator in H2O2-induced leaf cell death.As a free radical,NO could also react with other intracellular and extracellular targets and form a series of related molecules,collectively called reactive nitrogen species (RNS).Recent studies have revealed that both RNS and ROS are important partners in plant leaf cell death.Here,we summarize the recent progress on H2O2-induced leaf cell death and the crosstalk of RNS and ROS signals in the plant hypersensitive response (HR),leaf senescence,and other forms of leaf cell death triggered by diverse environmental conditions.

  10. Empirical electronic polarizabilities: deviations from the additivity rule. I. M2+SO4·nH2O, blödite Na2M2+(SO4)2·4H2O, and kieserite-related minerals with sterically strained structures

    Science.gov (United States)

    Gagné, Olivier; Hawthorne, Frank; Shannon, Robert D.; Fischer, Reinhard X.

    2017-09-01

    Empirical electronic polarizabilities allow the prediction of total mineral polarizabilities and mean refractive indices of the vast majority of minerals and synthetic oxides. However, deviations from the valence-sum rule at cations in some minerals are associated with large deviations of observed from calculated total polarizabilities. We have identified several groups of minerals and compounds where deviations from the valence-sum rule at cations lead to polarizability deviations of 2-5%: M(SO4)·nH2O, n = 1-6, blödite-group minerals [Na2M2+(SO4)2·4H2O], and the kieserite-related minerals: isokite, panasqueiraite and tilasite. In these minerals, the environment of the M ions contains both O and H2O: Mg[O4(H2O)2] in kieserite, szmikite, and szomolnokite; Mg[O2(H2O)4] in starkeyite, ilesite, and rozenite, and Mg[(H2O)6] in hexahydrite. In compounds where the ligands are only H2O, deviations from the valence-sum rule at the M(H2O)6 groups are not accompanied by significant polarizability deviations. This is the case for epsomite, MgSO4·7H2O; bieberite, CoSO4·7H2O; goslarite, ZnSO4·7H2O, six silicofluorides, MSiF6·6H2O; eighteen Tutton's salts, M2M'(SO4)2·6H2O, where M = K, Rb, Cs and M' = Mg, Mn, Fe, Co, Ni, Cu, and Zn; and eleven MM'(SO4)2·12H2O alums, where M = Na, K, Rb and Cs, and M' = Al, Cr, Ga and In. This is also the case for the sulfates alunogen, Al2(SO4)3·17H2O and halotrichite, FeAl2(SO4)4·22H2O; three hydrated nitrates; one phosphate; three antimonates and two hydrated perchlorates. A possible explanation for this different behavior is that the bond-valence model treats O and H separately, whereas polarizability calculations treat the polarizability of the entire H2O molecule.

  11. FTIR imaging in diffusion studies: CO2 and H2O in a synthetic sector-zoned beryl

    Directory of Open Access Journals (Sweden)

    Giancarlo eDella Ventura

    2015-06-01

    Full Text Available In this work we investigate the strongly inhomogeneous distribution of CO2 and H2O in a synthetic beryl having a peculiar hourglass zoning of Cr due to the crystal growth. The sample was treated at 800°C, 500 MPa, in a CO2-rich atmosphere. High-resolution FESEM images revealed that the hourglass boundary is not correlated to physical discontinuities, at least at the scale of tens of nanometers. Polarized FPA-FTIR imaging, on the other side, revealed that the chemical zoning acts as a fast pathway for carbon dioxide diffusion, a feature never observed so far in minerals. The hourglass zone boundary may be thus considered as a structural defect possibly due to the mismatch induced by the different growth rates of each sector. High-resolution synchrotron-light FTIR imaging, in addition, also allows enhancement of CO2 diffusion along the hourglass boundary to be distinguished from diffusion along fractures in the grain. Therefore, FTIR imaging provides evidence that different diffusion mechanisms may locally combine, suggesting that the distribution of the target molecules needs to be be carefully characterized in experimental studies. This piece of information is mandatory when the study is aimed at extracting diffusion coefficients from analytical profiles. Combination of TOF-SIMS and FPA data shows a significant depletion of type II H2O along the hourglass boundary, indicating that water diffusion could be controlled by the distribution of alkali cations within channels, coupled to a plug effect of CO2.

  12. Adsorption of H2O,OH,and O on CuCl(111) Surface: A Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    Xia Wang; Wen-kai Chen; Bao-zhen Sun; Chun-hai Lu

    2008-01-01

    The adsorption of H2O molecule and its dissociation products,O and OH,on CuCl(111) surface was studied with periodic slab model by PW91 approach of GGA within the framework of density functional theory.The results of geometry optimization indicate that the top site is stable energetically for H2O adsorbed over the CuCl(111) surface.The threefold hollow site is found to be the most stable adsorption site for OH and O,and the calculated adsorption energies are 309.5 and 416.5 k J/mol,respectively.Adsorption of H2O on oxygen-precovered CuCl(111) surface to form surface hydroxyl groups is predicted to be exothermic by 180.1 kJ/mol.The stretching vibrational frequencies,MuUiken population analysis and density of states analysis are employed to interpret the possible mechanism for the computed results.

  13. Manganese ions enhance mitochondrial H2O2 emission from Krebs cycle oxidoreductases by inducing permeability transition.

    Science.gov (United States)

    Bonke, Erik; Siebels, Ilka; Zwicker, Klaus; Dröse, Stefan

    2016-10-01

    Manganese-induced toxicity has been linked to mitochondrial dysfunction and an increased generation of reactive oxygen species (ROS). We could recently show in mechanistic studies that Mn(2+) ions induce hydrogen peroxide (H2O2) production from the ubiquinone binding site of mitochondrial complex II (IIQ) and generally enhance H2O2 formation by accelerating the rate of superoxide dismutation. The present study with intact mitochondria reveals that manganese additionally enhances H2O2 emission by inducing mitochondrial permeability transition (mPT). In mitochondria fed by NADH-generating substrates, the combination of Mn(2+) and different respiratory chain inhibitors led to a dynamically increasing H2O2emission which was sensitive to the mPT inhibitor cyclosporine A (CsA) as well as Ru-360, an inhibitor of the mitochondrial calcium uniporter (MCU). Under these conditions, flavin-containing enzymes of the mitochondrial matrix, e.g. the mitochondrial 2-oxoglutaratedehydrogenase (OGDH), were major sources of ROS. With succinate as substrate, Mn(2+) stimulated ROS production mainly at complex II, whereby the applied succinate concentration had a marked effect on the tendency for mPT. Also Ca(2+) increased the rate of H2O2 emission by mPT, while no direct effect on ROS-production of complex II was observed. The present study reveals a complex scenario through which manganese affects mitochondrial H2O2 emission: stimulating its production from distinct sites (e.g. site IIQ), accelerating superoxide dismutation and enhancing the emission via mPT which also leads to the loss of soluble components of the mitochondrial antioxidant systems and favors the ROS production from flavin-containing oxidoreductases of the Krebs cycle.

  14. Co(II)4, Co(II)7, and a Series of Co(II)2Ln(III) (Ln(III) = Nd(III), Sm(III), Gd(III), Tb(III), Dy(III)) Coordination Clusters: Search for Single Molecule Magnets.

    Science.gov (United States)

    Modak, Ritwik; Sikdar, Yeasin; Thuijs, Annaliese E; Christou, George; Goswami, Sanchita

    2016-10-03

    We report herein the syntheses and investigation of the magnetic properties of a Co(II)4 compound, a series of trinuclear Co(II)2Ln(III) (Ln(III) = Nd(III), Sm(III), Gd(III), Tb(III), Dy(III)) complexes, and a Co(II)7 complex. The homometallic Co(II)4 core was obtained from the reaction of Ln(NO3)3·xH2O/Co(NO3)2·6H2O/H2vab/Et3N in a 0.5:0.5:1:2 ratio in methanol. Variation in synthetic conditions was necessary to get the desired Co(II)-Ln(III) complexes. The Co(II)-Ln(III) assembly was synthesized from Ln(NO3)3·xH2O/Co(OAc)2·4H2O/H2vab/NaOMe in a 0.4:0.5:1:1 ratio in methanol. The isostructural Co(II)2Ln(III) complexes have a core structure with the general formula [Co2Ln(Hvab)4(NO3)](NO3)2·MeOH·H2O, (where H2vab = 2-[(2-hydroxymethyl-phenylimino)-methyl]-6-methoxy-phenol) with simultaneous crystallization of Co(II)7 complex in each reaction. The magnetic investigation of these complexes reveals that both homometallic complexes and four Co(II)-Ln(III) complexes (except Co(II)-Nd(III)) display behavior characteristic of single molecule magnets.

  15. Effect of H2O2 dosing strategy on sludge pretreatment by microwave-H2O2 advanced oxidation process.

    Science.gov (United States)

    Wang, Yawei; Wei, Yuansong; Liu, Junxin

    2009-09-30

    Considering characteristics of breaking down H(2)O(2) into water and molecular oxygen by catalase in waste activated sludge (WAS), the effect of H(2)O(2) dosing strategy on sludge pretreatment by the advanced oxidation process (AOP) of microwave-H(2)O(2) was investigated by batch experiments for optimizing H(2)O(2) dosage. Results showed that the catalase in sludge was active at the low temperature range between 15 degrees C and 45 degrees C, and gradually lost activity from 60 degrees C to 80 degrees C. Therefore, the H(2)O(2) was dosed at 80 degrees C, to which the waste activated sludge was first heated by the microwave (MW), and then the sludge dosed with H(2)O(2) was continuously heated till 100 degrees C by the microwave. Results at different H(2)O(2) dosages showed that the higher the H(2)O(2) dosing ratio was, the more the SCOD and total organic carbon (TOC) were released into the supernatant, and the optimum range of H(2)O(2)/TCOD ratio should be between 0.1 and 1.0. The percentages of consumed H(2)O(2) in the AOP of microwave and H(2)O(2) treating the WAS were 25.38%, 22.53%, 14.82%, 13.61% and 19.63% at different H(2)O(2)/TCOD dosing ratios of 0.1, 0.5, 1, 2, 4, respectively. Along with the increasing H(2)O(2)/TCOD ratio, the contents of TCOD on particles, soluble substances and mineralization increased and the TCOD distribution on solids decreased.

  16. Catalase activity is stimulated by H(2)O(2) in rich culture medium and is required for H(2)O(2) resistance and adaptation in yeast.

    Science.gov (United States)

    Martins, Dorival; English, Ann M

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  17. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast

    Directory of Open Access Journals (Sweden)

    Dorival Martins

    2014-01-01

    Full Text Available Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1 protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4. This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD and in phosphate buffer (pH 7.4. Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  18. Hydrothermal synthesis and structure of [(C4N2H12)3][P2Mo5O23]$\\cdot$H2O and [(C3N2H12)3][P2Mo5O23]$\\cdot$4H2O

    Indian Academy of Sciences (India)

    S V Ganesan; Srinivasan Natarajan

    2005-05-01

    Two new compounds, [(C4N2H12)3][P2Mo5O23]$\\cdot$H2O, I, and [(C3N2H12)3][P2Mo5O23]$\\cdot$4H2O, II, have been prepared employing hydrothermal methods in the presence of aliphatic organic amine molecules. Both the compounds possess the same polyoxoanion, pentamolybdatobisphosphate, (P2Mo5O23)6-. The anions consist of a ring of five MoO6 distorted octahedra with four edge connections and one corner connection. The phosphate groups cap the pentamolybdate ring anion on either side. The anion is stabilized by strong hydrogen bonds involving the hydrogen atoms of the amine molecules and the oxygen atoms of the polyoxoanion and water molecules. Crystal data: I, monoclinic, space group = 21/ (no. 14), mol. wt. = 1192.1, = 9.4180(1), = 18.1972(3), = 19.4509(1) Å, = 103.722(1)°, = 3238.37(7) Å3, = 4; II, triclinic, space group = 1 (no. 2), mol. wt. = 1210.1, = 9.5617(9), = 13.3393(12), = 13.7637(12) Å, = 88.735(1), = 75.68(1), = 87.484(2)°, = 1699.2(3) Å3.

  19. Visible spectrum photofragmentation of O3-(H2O)n, n ≤ 16

    Science.gov (United States)

    Lehman, Julia H.; Lineberger, W. Carl

    2014-10-01

    Photofragmentation of ozonide solvated in water clusters, O3-(H2O)n, n ≤ 16, has been studied as a function of photon energy as well as the degree of solvation. Using mass selection, the effect of the presence of the solvent molecule on the O3- photodissociation process is assessed one solvent molecule at a time. The O3- acts as a visible light chromophore within the water cluster, namely the O3-(H2O) total photodissociation cross-section exhibits generally the same photon energy dependence as isolated O3- throughout the visible wavelength range studied (430-620 nm). With the addition of a single solvent molecule, new photodissociation pathways are opened, including the production of recombined O3-. As the degree of solvation of the parent anion increases, recombination to O3--based products accounts for close to 40% of photoproducts by n = 16. The remainder of the photoproducts exist as O--based; no O2--based products are observed. Upper bounds on the O3- solvation energy (530 meV) and the O--OO bond dissociation energy in the cluster (1.06 eV) are derived.

  20. Synthesis and characterization of polymer eight-coordinate (enH2)[YIII(pdta)(H2O)](2)·10H2O as well as the interaction of [YIII(pdta)(H2O)]2(2-) with BSA.

    Science.gov (United States)

    Liu, Bin; Wang, Jun; Wang, Xin; Liu, Bing-Mi; He, Ling-Ling; Xu, Shu-Kun

    2010-12-01

    The eight-coordinate (enH2)[YIII(pdta)(H2O)](2)·10H2O (en=ethylenediamine and H4pdta=1,3-propylenediamine-N,N,N',N'-tetraacetic acid) was synthesized, meanwhile its molecular and crystal structures were determined by single-crystal X-ray diffraction technology. The interaction between [Y(III)(pdta)(H2O)]2(2-) and bovine serum albumin (BSA) was investigated by UV-vis and fluorescence spectra. The results indicate that [YIII(pdta)(H2O)]2(2-) quenched effectively the intrinsic fluorescence of BSA via a static quenching process with the binding constant (Ka) of the order of 10(4). Meanwhile, the binding and damaging sites to BSA molecules were also estimated by synchronous fluorescence. Results indicate that the hydrophobic environments around Trp and Tyr residues were all slightly changed. The thermodynamic parameters (ΔG=-25.20 kJ mol(-1), ΔH=-26.57 kJ mol(-1) and ΔS=-4.58 J mol(-1) K(-1)) showed that the reaction was spontaneous and exothermic. What is more, both ΔH and ΔS were negative values indicated that hydrogen bond and Van der Waals forces were the predominant intermolecular forces between [YIII(pdta)(H2O)]2(2-) and BSA. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Preparation, crystal structure, and characterization of an inorganic-organic hybrid polyoxoniobate [Cu(en)2]3[Cu(en)2(H2O)]1.5[K0.5Nb24O72H14.5]2.25H2O

    Indian Academy of Sciences (India)

    Jing-Ping Wang; Hong-Yu Niu; Jing-Yang Niu

    2008-05-01

    An inorganic-organic hybrid polyoxoniobate compound [Cu(en)2]3[Cu(en)2(H2O)]1.5 [K0.5Nb24O72H14.5]2.25H2O (1) was synthesized by reaction of K7HNb6O19.13H2O, Cu(CH3COOH)2.H2O and en (ethylenediamine) in aqueous solution and characterized by IR, ESR spectroscopy and singlecrystal X-ray diffraction method. Structure analysis indicates that compound 1 consists of a new type polyoxoniobate anion [K0.5Nb24O72H14.5]9-, three [Cu(en)2]2+, one point five [Cu(en)2(H2O)]2+, and two point two five crystal water molecules. The structure contains N-H$\\cdots$O hydrogen bonds between the coordinated ethylenediamine and the polyniobate-anion. The whole molecule possesses the 3 symmetry.

  2. Crystal Structure and Interaction with DNA of [Ni(phen)(mal)(H2O)2]·3H2O

    Institute of Scientific and Technical Information of China (English)

    GAO En-Jun; CHEN Mao-Sheng; YU Ying; SUN Ya-Guang

    2007-01-01

    A new complex [Ni(phen)(mal)(H2O)2]·3H2O (phen = 1,10-phenanthroline,mal2-= malonic acid) has been synthesized by the reaction of nickel nitrate,phen and malonic acid.EA,IR spectra and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure of the title complex.Crystal data:monoclinic system,space group P2/c,a =8.937(3),b = 12.163(5),c = 9.725(3)(A),β = 119.36°,C15H19N2O9Ni,Mr= 430.03,Z = 2,F(000) =446,V = 921.3 (A)3,Dc = 1.550 g/cm3,μ = 1.104 mm-1,-10≤h≤ 10,-12≤k≤ 14,-11 ≤l≤7,R =0.0261 and wR = 0.0609 for 4376 (Rint = 0.0203) independent reflections and 1631 observed ones (I> 2σ(I)).Ni(Ⅱ) exhibits an octahedral coordination geometry,with hydrogen bonds and π-π interactions stabilizing the whole structure.UV spectrum of the complex interacting with protamine DNA indicates that the title compound interacts with DNA via insertion mode with bonding constant Kb of 1.11 × 104.

  3. Responsive mechanism of a newly synthesized fluorescent probe for sensing H2O2, NO and H2O2/NO

    Science.gov (United States)

    Zhang, Yu-Jin; Wang, Xin; Zhou, Yong; Zhao, Ke; Wang, Chuan-Kui

    2016-10-01

    Optical properties of a newly synthesized fluorescent probe for H2O2, NO and H2O2/NO are investigated by employing time-dependent density functional theory. Three different sets of fluorescence signals are obtained when the probe reacts with H2O2, NO and H2O2/NO. Analysis of molecular orbitals is presented to explore responsive mechanism of the probe for the detected objects, where the fluorescent resonance energy transfer process is for H2O2 (H2O2/NO) and the intramolecular charge transfer process is for NO. Our results provide theoretical explanation of the experimental results, and importantly, suggest possibility of the probe as a two-photon fluorescent sensor.

  4. Dynamical Behaviour of H2O in Silica Gel

    Institute of Scientific and Technical Information of China (English)

    王燕; 董顺乐

    2002-01-01

    The vibrational spectra of silica gel with low concentrations of water, 3%0 and 10%, were studied by inelastic neutron scattering at 5 K. The experimental spectrum for 3% water in silica gelshows dramatic changes compared to the spectra for the other known ice phases in the energy transfer region of 2 - 140 meV. Its intermolecular librational band is shifted to lower energy by about 20meV (or by a factor of 1.43) compared to ice Ih, and shows a similar librational band with liquid at 290K. A significant excess of low-frequency vibration modes (< 7 meV)over normal ice Ih and a very wide acoustic peak (4 - 15 meV) were observed. Experimental data indicate that little H2O (3%) in silica gelexhibits a strong softening of hydrogen bonds compared to bulk normal ice and all the other known ice phases.

  5. Infrared Characters of Host Galaxies with H2O Megamaser

    Institute of Scientific and Technical Information of China (English)

    俞志尧

    2001-01-01

    Infrared characters of all the host galaxies with the H2O megamaser have been studied. The most striking featureis the anticorrelation of S(60)/S(100) versus S(12)/S(25), and S(25)/S(60) versus S(12)/S(25). The anticorrelationin the tlux density ratio can been explained by coexistence of large and very small dust particles. The latter, whichare heated by absorption of single photon, are believed to be responsible for the bulk of 12μm radiation. If thephoton energy of the host galaxy is small, this implies large S(12)/S(25) and small S(60)/S(100). However, whenphoton energy density becomes larger, the infrared spectrum will peak at wavelengths ≤ 100 μm and enhanceemission at 25 μm. As a consequence small S(12)/S(25) and large S(60)/S(100) are observed.

  6. Crystal Structure of Rare Earth Acrylates[Ln2(CH2 CHCOO)6·3H2O]·3H2O(Ln=Ce,Nd)%两种丙烯酸盐[Ln2(CH2CHCOO)6·3H2O]·3H2O(Ln=Ce;Nd)的单晶结构

    Institute of Scientific and Technical Information of China (English)

    钱玉英; 褚晓东; 姚有为

    2011-01-01

    Crystal strudures of [Ln2 (CH2CHCOO)6·3H2O](Ln = Ce,Nd) were characterized by using X - ray single crystal analysis. The title compounds are iso - structural: monoclime system, apace group P21/c with a= 1.02099 (13)nm,b = 1.52294(19) nm,c = 2.0325(3) nm,β= 100.838 (2)°, V = 3.1039 (7) nm3 for [ Ce2 ( CH2CHCOO) 6·3H2O] ;α=1.01978(8) nm, b=1.50979 (12) nm, c=2.02712 (16) nm,β=100.881 (1)°, V = 3.0650 (4) nm3 for [ND2 (CH2CHCOO)6·3H2O]. There are two independent Ln ions in the asymmetric unit, which are located in nona - coor-dinated and deca - coordinated environments respectively. The two Ln ions are bridged togetber by two μ2 - oxygen atoms of two independent acrylates, resulting in left - handed and right - handed helical chains. Hydrogen network are built up from helical chains and water molecules located between two neighbor chains. giying rise to three - dimensional stack.%采用X射线单晶衍射法,解析了[Ln2(CH:CHCOO)6·3H2O]·3H2O(Ln=Ce;Nd)的结构.结果表明标题化合物属同构:属单斜晶系(空间群P2(1)/c);[Ce2(CH2CHCOO)6·3H2O]·3H2O晶胞参数α=1.02099(13)nm,b=1.52294(19)nm,c=2.0325(3)nin,/3=100.838(2)°,V=3.1039(7)nm3;[Nd2(CH2CHCOO)6·3H2O]·3H2O晶胞参数α=1.01978(8)nm,6=1.50979(12)nm,c=2.02712(16)nm,β=100.881(1)°,V=3.0650(4)nm3.化合物不对称结构单元中含有两个独立的稀土中心离子,分别处九、十配位环境中.两个稀土离子由两个独立的丙烯酸μ2-氧桥联形成左手和右手螺旋链.螺旋链通过链间的水分子形成氢键网络,堆垛成三维结构.

  7. Synthesis, Crystal Structure and Magnetic Property of Sanwich-Type Heteropolyoxometalate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]·42H2O

    Institute of Scientific and Technical Information of China (English)

    XUE, Gang-Lin(薛岗林); WANG, Hu-Lin(王虎林); XIE, Zhi-Hai(谢志海); SHI, Qi-Zhen(史启祯); WANG, Ji-Wu(王继武); WANG, Da-Qi(王大奇)

    2004-01-01

    The heteropolytungstate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]·42H2O is obtained by the reaction of Na2WO4·2H2O, Bi(NO3)3·5H2O with CuCl2·2H2O at pH≈6. The structure and chemical composition are determined by X-ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are: a=1.410(3) nm, b=2.338(5) nm, c=3.173(6) nm, β=98.06(4)°, V=10.354(35) nm3, monoclinic crystal system, space group: C2/c, Z=4, R1=0.0471, wR2=0.0642 [I>2σ(I)], R1=0.1371, wR2=0.0868 (all data). [{Na(H2O)2}3{Cu(H2O)}3W9O33)2]9- has D3h symmetry. IR, UV-vis spectra, TG curve and magnetic property of the complex were also discussed. The compound exhibits an antiferromagnetic coupling with J=-8.08 cm-1 and g=2.21.

  8. Synthesis, spectral characterizations and biological studies of transition metal mixed ligand complexes: X-ray crystal structures of [Cu(oda)(Bipy)(H 2O)]·4H 2O and [VO(oda)(Bipy)]·2H 2O

    Science.gov (United States)

    Siddiqi, Zafar A.; Sharma, Prashant K.; Shahid, M.; Khalid, Mohd.; Kumar, Sarvendra

    2011-05-01

    The ternary complexes of stoichiometries [M(oda)(Bipy)H 2O]· xH 2O [M = Cu ( 1), x = 4; Co ( 2), x = 2; Ni ( 3), x = 4 or Cr ( 4), x = 3] and [VO(oda)(Bipy)]·2H 2O ( 5), where H 2oda = oxydiacetic acid and Bipy = 2,2'-bipyridine, were prepared and characterized employing elemental, FAB-Mass, FT-IR, EPR, 1H and 13C NMR spectroscopic analyses. X-ray crystallography of ( 1) and ( 5) indicated a six coordinate distorted geometry. The antimicrobial activities of the complexes were investigated against Escherichia coli(k-12), Bacillus subtilis (MTC-121), Staphylococcus aureus (IOASA-22), Salmonella typhymurium (MTCC-98), Candida albicans, Aspergillus fumigatus and Penicillium marneffei. The superoxide dismutase (SOD) mimic activity of the Cu(II) complex ( 1) was assessed employing NBT assay.

  9. Exchange interaction between TCNQ and transition metal ion mediated by hydrogen bonds in [Mn(phen)3](TCNQ)2·H2O and [Co(phen)3](TCNQ)2·H2O

    Science.gov (United States)

    Šoltésová, D.; Vasylets, G.; Čižmár, E.; Botko, M.; Cheranovskii, V.; Starodub, V.; Feher, A.

    2016-12-01

    The magnetic properties, specific heat and EPR spectra of anion-radical salts [Mn(phen)3](TCNQ)2·H2O and [Co(phen)3](TCNQ)2·H2O, in which TCNQ molecules and transition metal ions are not connected by covalent bonds and magnetic interactions are mediated via hydrogen bonds, were investigated. Measurements of the magnetic response were performed down to 1.8 K in magnetic fields up to 7 T. The heat capacity of investigated compounds was measured in temperature range from 0.38 K to 35 K in magnetic fields up to 9 T for [Mn(phen)3](TCNQ)2·H2O and up to 3 T for [Co(phen)3](TCNQ)2·H2O. The EPR spectra of studied samples were investigated for both samples in the temperature range from 2 K to 300 K. Theoretical model of weakly-coupled magnetic units composed of four TCNQ anion radicals and of two transition metal ions was proposed for interpretation of obtained data. The energy of exchange interactions between TCNQ molecules and transition metal ion is important for the description of low-temperature behavior of studied anion-radical salts and was estimated to be in the range of 1.3-1.5 K.

  10. Synthesis of high-surface-area spinel-type MgAl$_2$O$_4$ nanoparticles by [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] and [Mg(H$_2$O)$_6$][Al(ox)$_2$(H$_2$O)$_2$]$_2$·5H$_2$O: influence of inorganic precursor type

    Indian Academy of Sciences (India)

    2017-02-01

    Spinel-type MgAl$_2$O$_4$ nanoparticles with high surface area were synthesized by thermal decomposition of three different ion-pair complexes precursors, including [Mg(H$_2$O)$_6$][Al(dipic)$_2$]$_2$·6H$_2$O, [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] and [Mg(H$_2$O)$_6$][Al(ox)$_2$(H$_2$O)$_2$]$_2$·5H$_2$O. Influence of the inorganic precursor was investigated on synthesis and textural properties of magnesium aluminate nanopowders. The precursors [Mg(H$_2$O)$_6$][Al(dipic)$_2$]$_2$·6H$_2$O and [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] displayed pure spinel-type MgAl$_2$O$_4$, while the sample synthesized by [Mg(H$_2$O)$_6$][Al(ox)$_2$(H$_2$O)$_2$]$_2$·5H$_2$O precursor consisted of MgAl$_2$O$_4$ and MgO. The MgAl$_2$O$_4$ synthesizedvia [Al(sal)$_2$(H$_2$O)$_2$]$_2$[Mg(dipic)$_2$] precursor exhibited higher BET specific surface area (226.7 m$^2$ g$^{−1}$) and smaller particle size than those of the samples obtained from the two other precursors.

  11. Density functional study on the heterogeneous oxidation of NO over α-Fe2O3 catalyst by H2O2: Effect of oxygen vacancy

    Science.gov (United States)

    Song, Zijian; Wang, Ben; Yu, Jie; Ma, Chuan; Zhou, Changsong; Chen, Tao; Yan, Qianqian; Wang, Ke; Sun, Lushi

    2017-08-01

    Catalytic oxidation with H2O2 is a promising method for NOx emission control in coal-fired power plants. Hematite-based catalysts are attracting increased attention because of their surface redox reactivity. To elucidate the NO oxidation mechanism on α-Fe2O3 surfaces, density functional theory (DFT) calculations were conducted by investigating the adsorption characteristics of nitric oxide (NO) and hydrogen peroxide (H2O2) on perfect and oxygen defect α-Fe2O3 (0 0 1) surfaces. Results show that NO was molecularly adsorbed on two kinds of surfaces. H2O2 adsorption on perfect surface was also in a molecular form; however, H2O2 dissociation occurred on oxygen defect α-Fe2O3 (0 0 1) surface. The adsorption intensities of the two gas molecules in perfect α-Fe2O3 (0 0 1) surface followed the order NO > H2O2, and the opposite was true for the oxygen defect α-Fe2O3 (0 0 1). Oxygen vacancy remarkably enhanced the adsorption intensities of NO and H2O2 and promoted H2O2 decomposition on catalyst surface. As an oxidative product of NO, HNO2 was synthesized when NO and H2O2 co-adsorbed on the oxygen defect α-Fe2O3 (0 0 1) surface. Analyses of Mulliken population, electron density difference, and partial density of states showed that H2O2 decomposition followed the Haber-Weiss mechanism. The trends of equilibrium constants suggested that NO adsorption on α-Fe2O3 (0 0 1) surface was more favorable at low than at high temperatures, whereas H2O2 adsorption was favorable between 375 and 450 K. These calculations results well agreed with the experimental ones and further elucidates the reaction mechanisms.

  12. Investigation into the disparate origin of CO 2 and H 2O outgassing for comet 67P

    Science.gov (United States)

    Fink, Uwe; Doose, Lyn; Rinaldi, Giovanna; Capaccioni, Fabrizio; Bockelee-Morvan, Dominique; VIRTIS team

    2016-10-01

    We present an investigation of the emission intensity of CO2 and H2O and their distribution in the coma of 67P/ Churyumov-Gerasimenko obtained by the VIRTIS-M imaging spectrometer on the Rosetta mission. We analyze 4 data cubes from Feb. 28, and 7 data cubes from April 27, 2015. For both data sets the spacecraft was at a sufficiently large distance from the comet to allow images of the whole nucleus and the surrounding coma.We find that unlike water which has a reasonably predictable behavior and correlates well with the solar illumination, CO2 outgasses mostly in local regions or spots. Furthermore for the data on April 27, the CO2 evolves almost exclusively from the southern hemisphere, a region of the comet that has not received solar illumination since the comet's last perihelion passage. Because CO2 and H2O have such disparate origins, deriving mixing ratios from local column density measurements cannot provide a meaningful measurement of the CO2/H2O ratio in the coma of the comet. We obtain total production rates of H2O and CO2 by integrating the band intensity in an annulus surrounding the nucleus and obtain pro-forma production rate CO2/H2O mixing ratios of ~5.0% and ~2.5% for Feb. 28 and April 27 respectively. Because of the highly variable nature of the CO2 evolution we do not believe that these numbers are diagnostic of the comets bulk CO2/H2O composition. We believe that our investigation provides an explanation for the large observed variations reported in the literature for the CO2/H2O production rate ratios. Our mixing ratio maps indicate that, besides the difference in vapor pressure of the two gases, this ratio depends on the comet's geometric shape, illumination and past orbital history.Our annulus measurement for the total water production for Feb. 28 at 2.21AU from the sun is 2.5x1026 molecules/s while for April 27 at 1.76 AU it is 4.65x1026. We find that about 83% of the H2O resides in the illuminated portion of our annulus and about 17% on the

  13. Submillimeter H$_2$O and H$_2$O$^+$ emission in lensed ultra- and hyper-luminous infrared galaxies at z ~ 2-4

    CERN Document Server

    Yang, C; Beelen, A; González-Alfonso, E; Neri, R; Gao, Y; van der Werf, P; Weiß, A; Gavazzi, R; Falstad, N; Baker, A J; Bussmann, R S; Cooray, A; Cox, P; Dannerbauer, H; Dye, S; Guélin, M; Ivison, R; Krips, M; Lehnert, M; Michałowski, M J; Riechers, D A; Spaans, M; Valiante, E

    2016-01-01

    (abridged) We report rest-frame submillimeter H2O emission line observations of 11 HyLIRGs/ULIRGs at z~2-4 selected among the brightest lensed galaxies discovered in the Herschel-ATLAS. Using the IRAM NOEMA, we have detected 14 new H2O emission lines. The apparent luminosities of the H2O emission lines are $\\mu L_{\\rm{H_2O}} \\sim 6-21 \\times 10^8 L_\\odot$, with velocity-integrated line fluxes ranging from 4-15 Jy km s$^{-1}$. We have also observed CO emission lines using EMIR on the IRAM 30m telescope in seven sources. The velocity widths for CO and H2O lines are found to be similar. With almost comparable integrated flux densities to those of the high-J CO line, H2O is found to be among the strongest molecular emitters in high-z Hy/ULIRGs. We also confirm our previously found correlation between luminosity of H2O ($L_{\\rm{H_2O}}$) and infrared ($L_{\\rm{IR}}$) that $L_{\\rm{H_2O}} \\sim L_{\\rm{IR}}^{1.1-1.2}$, with our new detections. This correlation could be explained by a dominant role of far-infrared (FIR) ...

  14. Novel active heterogeneous Fenton system based on Fe3-xMxO4 (Fe, Co, Mn, Ni): the role of M2+ species on the reactivity towards H2O2 reactions.

    Science.gov (United States)

    Costa, Regina C C; Lelis, M F F; Oliveira, L C A; Fabris, J D; Ardisson, J D; Rios, R R V A; Silva, C N; Lago, R M

    2006-02-28

    In this work, the effect of incorporation of M2+ species, i.e. Co2+, Mn2+ and Ni2+, into the magnetite structure to increase the reactivity towards H2O2 reactions was investigated. The following magnetites Fe3-xMnxO4, Fe3-xCoxO4 and Fe3-xNixO4 and the iron oxides Fe3O4, gamma-Fe2O3 and alpha-Fe2O3 were prepared and characterized by Mössbauer spectroscopy, XRD, BET surface area, magnetization and chemical analyses. The obtained results showed that the M2+ species at the octahedral site in the magnetite strongly affects the reactivity towards H2O2, i.e. (i) the peroxide decomposition to O2 and (ii) the oxidation of organic molecules, such as the dye methylene blue and chlorobenzene in aqueous medium. Experiments with maghemite, gamma-Fe2O3 and hematite, alpha-Fe2O3, showed very low activities compared to Fe3O4, suggesting that the presence of Fe2+ in the oxide plays an important role for the activation of H2O2. The presence of Co or Mn in the magnetite structure produced a remarkable increase in the reactivity, whereas Ni inhibited the H2O2 reactions. The obtained results suggest a surface initiated reaction involving Msurf2+ (Fe, Co or Mn), producing HO radicals, which can lead to two competitive reactions, i.e. the decomposition of H2O2 or the oxidation of organics present in the aqueous medium. The unique effect of Co and Mn is discussed in terms of the thermodynamically favorable Cosurf3+ and Mnsurf3+ reduction by Femagnetite2+ regenerating the active species M2+.

  15. Surface abundance change in vacuum ultraviolet photodissociation of CO2 and H2O mixture ices.

    Science.gov (United States)

    Kinugawa, Takashi; Yabushita, Akihiro; Kawasaki, Masahiro; Hama, Tetsuya; Watanabe, Naoki

    2011-09-21

    Photodissociation of amorphous ice films of carbon dioxide and water co-adsorbed at 90 K was carried out at 157 nm using oxygen-16 and -18 isotopomers with a time-of-flight photofragment mass spectrometer. O((3)P(J)) atoms, OH (v = 0) radicals, and CO (v = 0,1) molecules were detected as photofragments. CO is produced directly from the photodissociation of CO(2). Two different adsorption states of CO(2), i.e., physisorbed CO(2) on the surface of amorphous solid water and trapped CO(2) in the pores of the film, are clearly distinguished by the translational and internal energy distributions of the CO molecules. The O atom and OH radical are produced from the photodissociation of H(2)O. Since the absorption cross section of CO(2) is smaller than that of H(2)O at 157 nm, the CO(2) surface abundance is relatively increased after prolonged photoirradiation of the mixed ice film, resulting in the formation of a heterogeneously layered structure in the mixed ice at low temperatures. Astrophysical implications are discussed.

  16. Redetermination of junitoite, CaZn2Si2O7·H2O

    Directory of Open Access Journals (Sweden)

    Hexiong Yang

    2012-10-01

    Full Text Available The crystal structure of the mineral junitoite, ideally CaZn2Si2O7·H2O (calcium dizinc disilicate monohydrate, was first determined by Hamilton & Finney [Mineral. Mag. (1985, 49, 91–95] based on the space group Ama2, yielding a reliability factor R of 0.10, with isotropic displacement parameters for all non-H atoms. The present study reports a structure redetermination of junitoite using single-crystal X-ray diffraction data from a natural sample, demonstrating that the space group of this mineral is actually Aea2, which can be attained simply by shifting the origin. Topologically, the structure models in the space groups Aea2 and Ama2 are analogous, consisting of chains of corner-sharing ZnO4 tetrahedra parallel to the b axis, cross-linked by Si2O7 tetrahedral dimers (the site symmetry of the bridging O atom is ..2 along a and c, forming a three-dimensional framework. The Ca2+ cations (site symmetry ..2 are situated in cavities of the framework and are bonded to five O atoms and one H2O molecule (site symmetry ..2 in a distorted octahedral coordination environment. However, some bond lengths, especially for the SiO4 tetrahedron, are noticeably different between the two structure models. Hydrogen bonding in junitoite is found between the water molecule and a framework O atom.

  17. Comparisons of multilayer H2O adsorption onto the (110) surfaces of alpha-TiO2 and SnO2 as calculated with density functional theory.

    Science.gov (United States)

    Bandura, Andrei V; Kubicki, James D; Sofo, Jorge O

    2008-09-18

    Mono- and bilayer adsorption of H2O molecules on TiO2 and SnO 2 (110) surfaces has been investigated using static planewave density functional theory (PW DFT) simulations. Potential energies and structures were calculated for the associative, mixed, and dissociative adsorption states. The DOS of the bare and hydrated surfaces has been used for the analysis of the difference between the H2O interaction with TiO2 and SnO 2 surfaces. The important role of the bridging oxygen in the H2O dissociation process is discussed. The influence of the second layer of H2O molecules on relaxation of the surface atoms was estimated.

  18. Synthesis and characterization of the open-framework barium bisphosphonate [Ba3(O3PCH2NH2CH2PO3)2(H2O)4].3H2O.

    Science.gov (United States)

    Bauer, Sebastian; Müller, Helen; Bein, Thomas; Stock, Norbert

    2005-12-12

    Following the strategy of using polyfunctional phosphonic acids for the synthesis of open-framework metal phosphonates, the phosphonocarboxylic acid (H2O3PCH2)2NCH2C6H4COOH was used in the hydrothermal synthesis of new Ba phosphonates. Its decomposition led to the first open-framework barium phosphonate [Ba3(O3PCH2NH2CH2PO3)2(H2O)4].3H2O. The synthesis was also successfully performed using iminobis(methylphosphonic acid), (H2O3PCH2)2NH, as a starting material, and the synthesis was optimized to obtain as a pure material. The reaction setup as well as the pH are the dominant parameters, and only a diffusion-controlled reaction led to the desired compound. The crystal structure was solved from single-crystal data: monoclinic; C2/c; a=2328.7(2), b=1359.95(7), and c=718.62(6) pm; beta=98.732(10) degrees ; V=2249.5(3)x10(6) pm3; Z=4; R1=0.036; and wR2=0.072 (all data). The structure of [Ba3(O3PCH2NH2CH2PO3)2(H2O)4].3H2O is built up from BaO8 and BaO10 polyhedra forming BaO chains and layers, respectively. These are connected to a three-dimensional metal-oxygen-metal framework with the iminobis(methylphosphonic acid) formally coating the inner walls of the pores. The one-dimensional pores (3.6x4 A) are filled with H2O molecules that can be thermally removed. Thermogravimetric investigations and temperature-dependent X-ray powder diffraction demonstrate the stability of the crystal structure up to 240 degrees C. The uptake of N,N-dimethylformamide and H2O by dehydrated samples is demonstrated. Furthermore, IR, Raman, and 31P magic-angle-spinning NMR data are also presented.

  19. Redetermination of metarossite, CaV5+2O6·2H2O

    Directory of Open Access Journals (Sweden)

    Anaïs Kobsch

    2016-09-01

    Full Text Available The crystal structure of metarossite, ideally CaV2O6·2H2O [chemical name: calcium divanadium(V hexaoxide dihydrate], was first determined using precession photographs, with fixed isotropic displacement parameters and without locating the positions of the H atoms, leading to a reliability factor R = 0.11 [Kelsey & Barnes (1960. Can. Mineral. 6, 448–466]. This communication reports a structure redetermination of this mineral on the basis of single-crystal X-ray diffraction data of a natural sample from the Blue Cap mine, San Juan County, Utah, USA (R1 = 0.036. Our study not only confirms the structural topology reported in the previous study, but also makes possible the refinement of all non-H atoms with anisotropic displacement parameters and all H atoms located. The metarossite structure is characterized by chains of edge-sharing [CaO8] polyhedra parallel to [100] that are themselves connected by chains of alternating [VO5] trigonal bipyramids parallel to [010]. The two H2O molecules are bonded to Ca. Analysis of the displacement parameters show that the [VO5] chains librate around [010]. In addition, we measured the Raman spectrum of metarossite and compared it with IR and Raman data previously reported. Moreover, heating of metarossite led to a loss of water, which results in a transformation to the brannerite-type structure, CaV2O6, implying a possible dehydration pathway for the compounds M2+V2O6·xH2O, with M = Cu, Cd, Mg or Mn, and x = 2 or 4.

  20. Reactivity of nano-size zinc powder in the aqueous solution of [Fe(III)(edta)(H2O)]().

    Science.gov (United States)

    Augustyniak, Adam W; Suchecki, Tomasz T; Kumazawa, Hidehiro

    2017-01-01

    Nitrogen mono-oxide and sulfur dioxide can be removed by simultaneous absorption into aqueous mixed solutions of sulfite and [Fe(II)(edta)]H2O)](2-), ferrous ion coordinated to an anion of ethylene-diaminetetraacetic acid (EDTA or edta). In the industrial system with coexisting oxygen in the gas phase, [Fe(II)(edta)](H2O)](2-) complex is oxidized to [Fe(III)(edta)](H2O)](-) by molecular oxygen. Because the ferric complex has no capability for reaction with NO, the suppression of this undesired oxidation process is a very important technological problem to be overcome. In our preceding work, we discussed the reduction kinetics of ferric ion by metal powder on the basis of the kinetic data regarding the ferric ion reduction in aqueous solutions of [Fe(III)(edta)](H2O)](-) containing aluminum, tin or zinc powders. Zinc powder of normal size was recognized as an effective reducing agent. In the present work, augmentation of reducing capability of zinc powder was examined more. The rate of reduction of nano-size zinc powder was found to be about 11 times higher than that of normal-size zinc one.

  1. Ionic hydrates, M(p)X(q).nH(2)O: lattice energy and standard enthalpy of formation estimation.

    Science.gov (United States)

    Jenkins, H Donald Brooke; Glasser, Leslie

    2002-08-26

    This paper is one of a series (see: Inorg. Chem. 1999, 38, 3609; J. Am. Chem. Soc. 2000, 122, 632; Inorg. Chem. 2002, 41, 2364) exploring simple approaches for the estimation of lattice energies of ionic materials, avoiding elaborate computation. Knowledge of lattice energy can lead, via thermochemical cycles, to the evaluation of the underlying thermodynamics involving the preparation and subsequent reactions of inorganic materials. A simple and easy to use equation for the estimation of the lattice energy of hydrate salts, U(POT)(M(p)X(q).nH(2)O) (and therefore for solvated salts, M(p)X(q).nS, in general), using either the density or volume of the hydrate, or of another hydrate, or of the parent anhydrous salt or the volumes of the individual ions, is derived from first principles. The equation effectively determines the hydrate lattice energy, U(POT)(M(p)X(q).nH(2)O), from a knowledge of the (estimated) lattice energy, U(POT)(M(p)X(q)), of the parent salt by the addition of ntheta(U) where theta(U)(H(2)O)/kJ mol(-1) = 54.3 and n is the number of water molecules. The average volume of the water molecule of hydration, V(m)(H(2)O)/nm(3) = 0.0245, has been determined from data on a large series of hydrates by plotting hydrate/parent salt volume differences against n. The enthalpy of incorporation of a gaseous water molecule into the structure of an ionic hydrate, [Delta(f)H degrees (M(p)X(q).nH(2)O,s) - Delta(f)H degrees (M(p)X(q),s) - nDelta(f)H degrees (H(2)O,g)], is shown to be a constant, -56.8 kJ (mol of H(2)O)(-1). The physical implications with regard to incorporation of the water into various types of solid-state structures are considered. Examples are given of the use of the derived hydrate lattice energy equation. Standard enthalpies of formation of a number of hydrates are thereby predicted.

  2. Stepwise mechanism and H2O-assisted hydrolysis in atomic layer deposition of SiO2 without a catalyst.

    Science.gov (United States)

    Fang, Guo-Yong; Xu, Li-Na; Wang, Lai-Guo; Cao, Yan-Qiang; Wu, Di; Li, Ai-Dong

    2015-01-01

    Atomic layer deposition (ALD) is a powerful deposition technique for constructing uniform, conformal, and ultrathin films in microelectronics, photovoltaics, catalysis, energy storage, and conversion. The possible pathways for silicon dioxide (SiO2) ALD using silicon tetrachloride (SiCl4) and water (H2O) without a catalyst have been investigated by means of density functional theory calculations. The results show that the SiCl4 half-reaction is a rate-determining step of SiO2 ALD. It may proceed through a stepwise pathway, first forming a Si-O bond and then breaking Si-Cl/O-H bonds and forming a H-Cl bond. The H2O half-reaction may undergo hydrolysis and condensation processes, which are similar to conventional SiO2 chemical vapor deposition (CVD). In the H2O half-reaction, there are massive H2O molecules adsorbed on the surface, which can result in H2O-assisted hydrolysis of the Cl-terminated surface and accelerate the H2O half-reaction. These findings may be used to improve methods for the preparation of SiO2 ALD and H2O-based ALD of other oxides, such as Al2O3, TiO2, ZrO2, and HfO2.

  3. The new triazine-based porous copper phosphonate [Cu3(PPT)(H2O)3]·10H2O.

    Science.gov (United States)

    Hermer, N; Stock, N

    2015-02-28

    High throughput methods were employed in the discovery of [Cu3(PPT)(H2O)3]·10H2O (denoted CAU-14). The structure contains one-dimensional channels with a diameter of 9.4 Å. Thermal activation leads to the formation of uncoordinated metal sites and a high water uptake of 39.1 wt% was found.

  4. Investigation into the disparate origin of CO2 and H2O outgassing for Comet 67/P

    Science.gov (United States)

    Fink, Uwe; Doose, Lyn; Rinaldi, Giovanna; Bieler, André; Capaccioni, Fabrizio; Bockelée-Morvan, Dominique; Filacchione, Gianrico; Erard, Stephane; Leyrat, Cedric; Blecka, Maria; Capria, Maria Teresa; Combi, Michael; Crovisier, Jacques; De Sanctis, Maria Cristina; Fougere, Nicolas; Taylor, Fred; Migliorini, Alessandra; Piccioni, Giuseppe

    2016-10-01

    molecules/s while for April 27 at 1.76 AU it is 4.65 × 1026. We find that about 83% of the H2O resides in the illuminated portion of our annulus and about 17% on the night side. We also make an attempt to obtain the fraction of the H2O production coming from the highly active neck of the comet versus the rest of the illuminated surface from the pole-on view of Feb. 28 and estimate that about 60% of the H2O derives from the neck area. A rough estimate of the water surface evaporation rate of the illuminated nucleus for April 27 yields about 5 × 1019 molecules/s/m2. Spatial radial profiles of H2O on April 27 on the illuminated side of the comet, extending from 1.78 to 6.47 km from the nucleus center, show that water follows model predictions quite well, with the gas accelerating as it expands into the coma. Our dayside radial profile allows us to make an empirical determination of the expansion velocity of water. On the night side the spatial profile of water follows 1/ρ. The CO2 profiles do not exhibit any acceleration into the coma but are closely matched by a 1/ρ profile.

  5. The investigation of structure and IR spectra for hydrated potassium ion clusters K+(H2O)n=1-16 by density functional theory*

    Science.gov (United States)

    Zhu, Fayan; Zhou, Hongxia; Zhou, Yongquan; Miao, Juntao; Fang, Chunhui; Fang, Yan; Sun, Pengchao; Ge, Haiwen; Liu, Hongyan

    2016-11-01

    The hydration of K+(H2O)n has been widely studied and believe to be important for understanding solvent properties in biological and chemical systems. However, understanding the structure and the spectrum information K+(H2O)n with changing n is limited. Here, we investigated the clusters K+(H2O)n=1-16 and further studied the IR spectrums of the most stable clusters with density functional theory. The configuration, bond length, vibration frequency were given out. It shows that K+(H2O)8(H2O)n, a distorted square antiprism in inner layer, is the main configuration with hydration distance rK - OI 0.296 nm when the hydration number n is bigger than 8. The saturated hydration number is 8 in the first hydration layer and the water molecules of the second hydration sphere have little effect on the inner ones when n> 8. A detailed classification about the hydrated water molecules was made according to the role of acceptor or donor hydrogen bonding in clusters. The vibration frequency of the different kinds of water molecules were also detailly identified. The results are valuable for further determination of the K+(H2O)n clusters in aqueous solutions. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-60529-7

  6. Thorium divanadate dihydrate, Th(V2O7(H2O2

    Directory of Open Access Journals (Sweden)

    Mohamed Saadi

    2011-10-01

    Full Text Available The title compound, Th(V2O7(H2O2, was synthesized by a hydrothermal reaction. The crystal structure consists of ThO7(OH22 tricapped trigonal prisms that share edges, forming [ThO5(OH22]n chains along [010]. The edge-sharing ThO7(OH22 polyhedra share one edge and five vertices with the V2O7 divanadate anions having a nearly ecliptic conformation parallel to [001]. This results in an open framework with the water molecules located in channels. O—H...O hydrogen bonding between water molecules and framework O atoms is observed. Bond-valence-sum calculations are in good agreement with the chemical formula of the title compound.

  7. Vibrational spectra of Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·nH2O (n = 4, 6) with a crystal structure determination of the Tutton salt Cs2Cu(SeO4)2·6H2O

    Science.gov (United States)

    Wildner, M.; Marinova, D.; Stoilova, D.

    2016-02-01

    The solubility in the three-component systems Cs2SO4-CuSO4-H2O and Cs2SeO4-CuSeO4-H2O have been studied at 25 °C. The experimental results show that double salts, Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·4H2O, crystallize from the ternary solutions within large concentration ranges. Crystals of Cs2Cu(SeO4)2·6H2O were synthesized at somewhat lower temperatures (7-8 °C). The thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the respective dehydration schemes are proposed. The calculated enthalpies of dehydration (ΔHdeh) have values of: 434.2 kJ mol-1 (Cs2Cu(SeO4)2·6H2O), 280.9 kJ mol-1 (Cs2Cu(SeO4)2·4H2O), and 420.2 kJ mol-1 (the phase transition of Cs2Cu(SO4)2·6H2O into Cs2Cu(SO4)2·H2O). The crystal structure of Cs2Cu(SeO4)2ṡ6H2O was determined from single crystal X-ray diffraction data. It belongs to the group of Tutton salts, crystallizing isotypic to the respective sulfate in a monoclinic structure which is characterized by isolated Cu(H2O)6 octahedra and SeO4 tetrahedra, interlinked by hydrogen bonds and [9]-coordinated Cs+ cations. Infrared spectra of the cesium copper compounds are presented and discussed with respect to both the normal modes of the tetrahedral ions and the water molecules. The analysis of the infrared spectra of the double compounds reveals that the distortion of the selenate tetrahedra in Cs2Cu(SeO4)2·4H2O is stronger than those in Cs2Cu(SeO4)2·6H2O in agreement with the structural data. Matrix-infrared spectroscopy was applied to confirm this claim - Δν3 for SO4 2 - ions matrix-isolated in Cs2Cu(SeO4)2·6H2O has a value of 35 cm-1 and that of the same ions included in Cs2Cu(SeO4)2·4H2O - 84 cm-1. This spectroscopic finding is due to the formation of strong covalent bands Cu-OSO3 on one hand, and on the other to the stronger deformation of the host SeO4 2 - tetrahedra in Cs2Cu(SeO4)2·4H2O as compared to those in Cs2Cu(SeO4)2·6H2O. The strength of the hydrogen bonds as deduced from the

  8. Synthesis and Crystal Structure of [La(BTC)(H2O)6]n

    Institute of Scientific and Technical Information of China (English)

    WEN Yi-Hang; CHENG Jian-Kai; FENG Yun-Long; ZHANG Jian; LI Zhao-Ji; YAO Yuan-Gen

    2005-01-01

    The title compound, [La(BTC)(H2O)6]n 1 (H3BTC = benzene-1,3,5-tricarboxylic acid), has been synthesized by the hydrothermal reaction of La(NO3)3·3H2O with H3BTC and Na2CO3, and its structure was determined by single-crystal X-ray diffraction. The crystal structure is of monoclinic, space group Cc with a = 11.5289(3), b = 18.0383(7), c = 7.3507(3)(A), β = 119.5680(10)o, V = 1329.59(8)(A)3, C9H15LaO12, Mr = 454.12, Z = 4, Dc = 2.269 g/cm3, μ = 3.280 mm-1, Flack parameter = 0.07(4), F(000) = 888, R = 0.0316 and wR = 0.0774 for 1312 observed reflections(I > 2σ(I)). Complex 1 features a one-dimensional (1-D) parallel ribbon-like structure. There are extensive hydrogen-bonding interactions involving coordinated water molecules and free carboxylate oxygen atoms. In addition, π-π interactions via benzoic multicarboxylate ligands are discussed. These non-covalent interactions lead to the formation of a 3-D framework.

  9. H2O2 in plant peroxisomes: an in vivo analysis uncovers a Ca2+-dependent scavenging system

    Science.gov (United States)

    Costa, Alex; Drago, Ilaria; Behera, Smrutisanjita; Zottini, Michela; Pizzo, Paola; Schroeder, Julian I; Pozzan, Tullio; Schiavo, Fiorella Lo

    2010-01-01

    Summary Oxidative stress is a major challenge for all cells living in an oxygen-based world. Among reactive oxygen species, H2O2, is a well known toxic molecule and, nowadays, considered a specific component of several signalling pathways. In order to gain insight into the roles played by H2O2 in plant cells, it is necessary to have a reliable, specific and non-invasive methodology for its in vivo detection. Hence, the genetically-encoded H2O2 sensor HyPer was expressed in plant cells in different subcellular compartments such as cytoplasm and peroxisomes. Moreover, with the use of the new GFP-based Cameleon Ca2+ indicator, D3cpv-KVK-SKL, targeted to peroxisomes, we demonstrated that the induction of cytoplasmic Ca2+ increase is followed by Ca2+ rise in the peroxisomal lumen. The analyses of HyPer fluorescence ratios were performed in leaf peroxisomes of tobacco and pre- and post-bolting Arabidopsis plants. These analyses allowed us to demonstrate that an intraperoxisomal Ca2+ rise in vivo stimulates catalase activity, increasing peroxisomal H2O2 scavenging efficiency. PMID:20230493

  10. Synthesis, structural investigation and thermal properties of a novel manganese complex Mn2(DAT)2Cl4(H2O)4 (DAT=1,5-diaminotetrazole).

    Science.gov (United States)

    Zhang, Jian-Guo; Li, Zhi-Min; Zang, Yan; Zhang, Tong-Lai; Shu, Yuan-Jie; Yang, Li; Power, Philip P

    2010-06-15

    A novel manganese complex Mn(2)(DAT)(2)Cl(4)(H(2)O)(4), where DAT is 1,5-diaminotetrazole, was synthesized by the reaction of manganese(II) chloride tetrahydrate and 1,5-diaminotetrazole (DAT) in ethanol, and characterized by elemental analysis, FT-IR spectroscopy. The crystal structure was determined through X-ray single crystal diffraction. The molecular unit of Mn(2)(DAT)(2)Cl(4)(H(2)O)(4) has a distorted octahedral structure, containing two central manganese cations, which coordinated by a mono-dentate terminal chloride, a bulky DAT ligand and two water molecules, and linked by two bidentate bridging chloride ligands. There are two main exothermic peaks and one endothermic peak in the thermal decomposition process, investigated by differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA), the final residue of the title compound at 600 degrees C is MnO. The kinetic parameters of the endothermic process and two main exothermic processes were studied by applying the Kissinger's and Ozawa-Doyle's methods.

  11. Photoelectron spectroscopic study of the hydrated nucleoside anions: Uridine(-)(H(2)O)(n=0-2), cytidine(-)(H(2)O)(n=0-2), and thymidine(-)(H(2)O)(n=0,1).

    Science.gov (United States)

    Li, Xiang; Wang, Haopeng; Bowen, Kit H

    2010-10-14

    The hydrated nucleoside anions, uridine(-)(H(2)O)(n=0-2), cytidine(-)(H(2)O)(n=0-2), and thymidine(-)(H(2)O)(n=0,1), have been prepared in beams and studied by anion photoelectron spectroscopy in order to investigate the effects of a microhydrated environment on parent nucleoside anions. Vertical detachment energies (VDEs) were measured for all eight anions, and from these, estimates were made for five sequential anion hydration energies. Excellent agreement was found between our measured VDE value for thymidine(-)(H(2)O)(1) and its calculated value in the companion article by S. Kim and H. F. Schaefer III.

  12. Photoelectron spectroscopic study of the hydrated nucleoside anions: Uridine-(H2O)n=0-2, cytidine-(H2O)n=0-2, and thymidine-(H2O)n=0,1

    Science.gov (United States)

    Li, Xiang; Wang, Haopeng; Bowen, Kit H.

    2010-10-01

    The hydrated nucleoside anions, uridine-(H2O)n=0-2, cytidine-(H2O)n=0-2, and thymidine-(H2O)n=0,1, have been prepared in beams and studied by anion photoelectron spectroscopy in order to investigate the effects of a microhydrated environment on parent nucleoside anions. Vertical detachment energies (VDEs) were measured for all eight anions, and from these, estimates were made for five sequential anion hydration energies. Excellent agreement was found between our measured VDE value for thymidine-(H2O)1 and its calculated value in the companion article by S. Kim and H. F. Schaefer III.

  13. [Bi2Cl10(H2-Norf)4(H2O)8] where H-Norf is Norfloxacin(R)%[Bi2Cl10(H2-Norf)4(H2O)8](H-Norf是诺氟沙星)

    Institute of Scientific and Technical Information of China (English)

    李咏华; 熊仁根

    2005-01-01

    The crystal structure of [Bi2Cl10(H2-Norf)4(H2O)s] (1) comprises [H2-Norf]+ cations and [Bi2Cl10]4- anions,that are loosely associated via H-bonding interactions, as well as water molecules that also participate in H-bond-ing interactions. Strong blue-fluorescent emission of 1 at solid state is observed at the room temperature. CCDC:238237.

  14. The Photochemistry of Pyrimidine in Pure H2O Ice Subjected to Different Radiation Environments and the Formation of Uracil

    Science.gov (United States)

    Nuevo, M.; Chen, Y.-J.; Materese. C. K..; Hu, W.-J.; Qiu, J.-M.; Wu, S.-R.; Fung, H.-S.; Sandford, S. A.; Chu, C.-C.; Yih, T.-S.; Wu, R.; Ip, W.-H.

    2013-01-01

    Nucleobases are N-heterocycles which are the informational subunits of DNA and RNA. They include pyrimidine bases (uracil, cytosine, and thymine) and purine bases (adenine and guanine). Nucleobases have been detected in several meteorites, although no Nheterocycles have been observed in space to data. Laboratory experiments showed that the ultraviolet (UV) irradiation of pyrimidine in pure H2O ice at low temperature (<=20 K) leads to the formation of pyrimidine derivatives including the nucleobase uracil and its precursor 4(3H)-pyrimidone. These results were confirmed by quantum chemical calculations. When pyrimidine is mixed with combinations of H2O, NH3, CH3OH, and CH4 ices under similar conditions, uracil and cytosine are formed. In the present work we study the formation of 4(3H)-pyrimidone and uracil from the irradiation of pyrimidine in H2O ice with high-energy UV photons (Lyman , He I, and He II lines) provided by a synchrotron source. The photo-destruction of pyrimidine in these H2O ices as well as the formation yields for 4(3H)-pyrimidone and uracil are compared with our previous results in order to study the photo-stability of pyrimidine and the production efficiency of uracil as a function of the photon energy.

  15. H2O SOS: It Begins With You

    Science.gov (United States)

    Ingalls, G.; Weiss, I.

    2016-12-01

    ExplorOcean H2O SOS: Help Heal the Ocean—Student Operated Solutions: Operation Climate Change teaches middle and high school students about ocean threats related to climate change through hands-on activities and learning experiences in the field. In this research we study five areas of focus. Marine Debris: The Ocean is one large system with a general circulation pattern and debris will be transported around the globe. Ocean Acidification: CO2 is the shortened term for Carbon Dioxide and it is a colorless and odorless gas vital to life on earth. This naturally occurring chemical compound is composed of a carbon atom covalently double bonded to two oxygen atoms. To much CO2 in the atmosphere can become an issue for our plants due to the chemicals strong greenhouse gas effects. Sustainable Fishing: Investigate and understand the impact fishing has on the habitats and the disruption of our ecosystem. Invasive Species: Species have been moved, intentionally or unintentionally as a result of human activity, into areas where they do not occur naturally are called "introduced" or "alien species". Watersheds and storm water: Water quality is not just a coastal issue. It starts in all regions and affects water quality from the mountains to the ocean. We get much of our water here in Southern California from the Colorado River. Imagine if the citizens of Colorado polluted all their water resources. We would not be able to continue using the Colorado River for fresh water. This issue affects everyone, and all people must help try to keep our fresh water resources clean.

  16. Cutin monomers and surface wax constituents elicit H2O2 in conditioned cucumber hypocotyl segments and enhance the activity of other H2O2 elicitors

    Science.gov (United States)

    Fauth; Schweizer; Buchala; Markstadter; Riederer; Kato; Kauss

    1998-08-01

    Hypocotyls from etiolated cucumber (Cucumis sativus L.) seedlings were gently abraded at their epidermal surface and cut segments were conditioned to develop competence for H2O2 elicitation. Alkaline hydrolysates of cutin from cucumber, tomato, and apple elicited H2O2 in such conditioned segments. The most active constituent of cucumber cutin was identified as dodecan-1-ol, a novel cutin monomer capable of forming hydrophobic terminal chains. Additionally, the cutin hydrolysates enhanced the activity of a fungal H2O2 elicitor, similar to cucumber surface wax, which contained newly identified alkan-1,3-diols. The specificity of elicitor and enhancement activity was further elaborated using some pure model compounds. Certain saturated hydroxy fatty acids were potent H2O2 elicitors as well as enhancers. Some unsaturated epoxy and hydroxy fatty acids were also excellent H2O2 elicitors but inhibited the fungal elicitor activity. Short-chain alkanols exhibited good elicitor and enhancer activity, whereas longer-chain alkan-1-ols were barely active. The enhancement effect was also observed for H2O2 elicitation by ergosterol and chitosan. The physiological significance of these observations might be that once the cuticle is degraded by fungal cutinase, the cutin monomers may act as H2O2 elicitors. Corrosion of cutin may also bring surface wax constituents in contact with protoplasts and enhance elicitation.

  17. Application of H2O2 and H2O2/Fe0 in removal of Acid Red 18 dye from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Nazari Shahram

    2013-08-01

    Full Text Available Background & Aims of the Study: Organic dyes with a complex structure are often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment and if released to the environment without treatment can endanger the environment and human health. The aim of this study was to evaluate the performance of H2O2 and H2O2/Fe0 Iron in removal of dye Acid Red 18 from aqueous solutions. Materials & Methods: This study was conducted at the laboratory scale. In this study, the removal efficiency of Acid Red 18 from a synthetic solution by H2O2 and H2O2/Fe0 was investigated. As well as Effect of solution pH, dye concentration, Concentration of Nanoscale Zero-Valent Iron, H2O2 and contact time in decolorization efficiency was investigated. Results: Results show that in pH=3, Contact time of 80 minutes, dye concentration of 50 mg/l and Concentration of Nanoscale Zero-Valent Iron of 2 g/l and H2O2 concentration equal to 200 mmol/l, the removal efficiency was about 98%. Conclusions: According to the results of experiments, H2O2/Fe0 has high efficiency in removal of Acid Red 18 from aqueous solution.

  18. Synthesis and Structural Determination of Binuclear Nine-Coordinate K4[Y2(Httha)2]·14H2O

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A Y3+ complex with triethylenetetraaminehexaacetic acid was prepared and its composition and structure were determined as K4[Y2(Httha)2]*14H2O by elemental analysis and single-crystal X-ray four circle diffraction analysis. In the binuclear complex, the two YN3O6 parts all form nine-coordinate monocapped square anti prismatic structures. There are a lot of water molecules in the unit cell which form hydrogen bonds.

  19. Effect of exogenous H2O2 on antioxidant enzymes of Brassica juncea L. seedlings in relation to 24-epibrassinolide under chilling stress.

    Science.gov (United States)

    Kumar, Manish; Sirhindi, Geetika; Bhardwaj, Renu; Kumar, Sandeep; Jain, Gagandeep

    2010-12-01

    Hydrogen peroxide is most stable molecule among reactive oxygen species, which play a vital role in growth and development of plant as signaling molecule at low concentration in response to various abiotic and biotic stresses. Exogenous application of H2O2 is known to induce chilling tolerance in plants. Brassinosteroids are plant steroid hormones known for their anti-stress properties. In this study, effect of exogenous H2O2 on antioxidant defense system of Brassica juncea L. seedlings was investigated in 24-epibrassinolide (24-EBL) treated and untreated seedlings under chilling stress. The surface sterilized seeds of B. juncea L. were germinated in petriplates containing different concentrations of H2O2 alone and in combination with 10(-8) M 24-EBL. Chilling treatment (4 degrees C) was given to 10-days old seedlings grown in different treatments for 6 h daily up to 3 days. 24 h recovery period was given to chilling treated seedlings by placing at 25 degrees C + 2 degrees C and harvested for antioxidant enzymes on 14th day after sowing (DAS). Treatment of 24-EBL in combination with H2O2 (15 and 20 mM) helped in reducing the toxicity of seed and seedlings due to H2O2 exposure on their germination rate, shoot and root length respectively. 24-EBL treatment at seed and seedling stage helped in alleviating the toxic effect of H2O2 through antioxidant defense system by increasing the activities of various enzymes involved in antioxidant defense system such as catalase (CAT, E.C. 1.11.1.6), ascorbate peroxidase (APOX, E.C. 1.11.1.11), and superoxide dismutase (SOD, E.C. 1.15.1.1). In conclusion, exogenous pretreatment of H2O2 to seeds of B. juncea L. adapted the seedlings to tolerate chilling stress, which was further ameliorated in combination of H2O2 with 24-EBL.

  20. H 2O in basalt and basaltic andesite glass inclusions from four subduction-related volcanoes

    Science.gov (United States)

    Sisson, T. W.; Layne, G. D.

    1993-06-01

    Total dissolved H 2O and major element abundances were measured in basalt and basaltic andesite glass inclusions in olivine phenocrysts from Quaternary eruptions of four subduction-related volcanoes to test the hypothesis that low-MgO high-alumina basalts contain high H 2O at depth [1] and to reveal any petrogenetically significant correlations between arc basalt compositions and H 2O contents. Total dissolved H 2O (combined molecular H 2O and OH groups) measured by ion microprobe in mafic glass inclusions from the 1974 eruption of Fuego, Guatemala, reaches 6.2 wt.%. Dissolved H 2O contents decrease in more evolved Fuego glasses. Correlations of H 2O with MgO, Na 2O, K 2O, S and Cl indicate that aqueous fluid exsolution during magma ascent forced crystallization and differentiation of residual liquids. Low-K 2O magnesian high-alumina basalt glass inclusions from the 3 ka eruption of Black Crater (Medicine Lake volcano, California) have low H 2O contents, near 0.2 wt.%, which are consistent with the MORB-like character of these and other primitive lavas of the Medicine Lake region. Basalt and basaltic andesite glass inclusions from Copco Cone and Goosenest volcano on the Cascade volcanic front north of Mt. Shasta have H 2O contents of up to 3.3 wt.%. The range of H 2O contents in Cascade mafic magmas is too large to have resulted solely from enrichment by crystallization and indicates the participation of an H 2O-rich component in magma generation or crustal-level modification. Whereas fluid-absent melting of amphibole-bearing peridotite can account for the H 2O in most mafic arc liquids, the very high H 2O/alkali ratios of the 1974 Fuego eruptives suggest that an aqueous fluid was involved in the generation of Fuego basalts.

  1. Thermodynamic properties and crystal structure refinement of ferricopiapite, coquimbite, rhomboclase, and Fe2(SO4)3(H2O)5

    Science.gov (United States)

    Majzlan, J.; Navrotsky, A.; McCleskey, R.B.; Alpers, C.N.

    2006-01-01

    Enthalpies of formation of ferricopiapite [nominally Fe4.67(SO4)6(OH)2 (H2O)20]. coquimbite [Fe2(SO4)3(H2O)9], rhomboclase [(H3O)Fe(SO4)2 (H2O)3], and Fe2(SO4)3(H2O)5 were measured by acid (5 N HCl) solution calorimetry. The samples were characterized by wet chemical analyses and synchrotron powder X-ray diffraction (XRD). The refinement of XRD patterns gave lattice parameters, atomic positions, thermal factors, and occupancies of the sites. The calculated formulae differ slightly from the nominal compositions: Fe4.78(SO4)6 (OH)2.34(H2O)20.71 (ferricopiapite), (Fe1.47Al0.53)(SO4)3 (H2O)9.65 (coquimbite), (H3O)1.34Fe(SO4)2.17 (H2O)3.06 (rhomboclase), and Fe2(SO4)3 (H2O)5.03. All thermodynamic data are given per mole of these formulae. The measured standard enthalpies (in kJ/mol) of formation from the elements (crystalline Fe, Al, S, and ideal gases O2 and H2) at T = 298.15 K are -4115.8??4.1 [Fe2(SO4)3 (H2O)5.03], -12045.1??9.2 (ferricopiapite), -5738.4??3.3 (coquimbite), and -3201.1??2.6 (rhomboclase). Standard entropy (S??) was estimated as a sum of entropies of oxide, hydroxide, and sulfate components. The estimated S?? (in J/mol.K) values for the iron sulfates are 488.2 [Fe2(SO4)3 (H2O)5.03], 1449.2 (ferricopiapite), 638.3 (coquimbite), and 380.1 (rhomboclase). The calculated Gibbs free energies of formation (in kJ/mol) are -3499.7??4.2 [Fe2(SO4)3 (H2O)5.03], -10089.8??9.3 (ferricopiapite), -4845.6??3.3 (coquimbite), and -2688.0??2.7 (rhomboclase). These results combined with other available thermodynamic data allow construction of mineral stability diagrams in the FeIII2(SO4)3-FeII SO4-H2O system. One such diagram is provided, indicating that the order of stability of ferric sulfate minerals with decreasing pH in the range of 1.5 to -0.5 is: hydronium jarosite, ferricopiapite, and rhomboclase. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.

  2. Crystal structure of NH4[La(SO42(H2O

    Directory of Open Access Journals (Sweden)

    Meriem Benslimane

    2015-06-01

    Full Text Available The principal building units in the crystal structure of ammonium aquabis(sulfatolanthanate(III are slightly distorted SO4 tetrahedra, LaO9 polyhedra in the form of distorted tricapped trigonal prisms, and NH4+ ions. The La3+ cation is coordinated by eight O atoms from six different sulfate tetrahedra, two of which are bidentate coordinating and four monodentate, as well as one O atom from a water molecule; each sulfate anion bridges three La3+ cations. These bridging modes result in the formation of a three-dimensional anionic [La(SO42(H2O]− framework that is stabilized by O—H...O hydrogen-bonding interactions. The disordered ammonium cations are situated in the cavities of this framework and are hydrogen-bonded to six surrounding O atoms.

  3. Synthesis and Crystal Structure of Triacetyltribenzyl-Hexaazaisowurtzitane (TATBIW·0.5 H2O)

    Institute of Scientific and Technical Information of China (English)

    Wei Rong HAN; Yu Xiang OU; Jin Quan LIU; Jian Long WANG

    2004-01-01

    The compound of tetraacetyldibenzylhexaazaisowurtzitane (TADBIW) is an important precursor of synthesizing the high energetic dense compound of hexanitrohexaazaisowurtzitane (HNIW). We can obtain TADBIW by using hydrogenolysis of hexabenzylhexaazaisowurtzitane (HBIW). In the process of hydrogenolysis of HBIW, it will generate a variety of intermediates, one of them is the compound of triacetyltribenzylhexaazaisowurtzitane (TATBIW). We have synthesized the title compound and prepared its single crystal. In the paper, the crystal and molecular structure of TATBIW.0.5H2O is described. Its crystal belongs to the triclinie and space group P-1. The cell is comprised of two TATBIW and one water molecules. The success of synthesizing TATB1W can help us to research the mechanism of the reduction of HBIW and produce high yields of the end products.

  4. Magnetic Properties of a Three-dimensional Supramolecular Complex[Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2%三维超分子配合物[Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2的磁性质(英文)

    Institute of Scientific and Technical Information of China (English)

    李纲; 李金鹏; 王翠红; 李林科; 侯红卫

    2002-01-01

    Supramolecular complex [Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2 (hmt =hexamethylenetetramine) is prepared according to previous literature. The determination of variable-temperature magnetic susceptibilities (5~300 K) shows that the magnetic behavior obeys the Curie-Weiss law over the whole temperature range. In this compound weak antiferromagnetic coupling can be observed.%参照文献制备了三维超分子配合物[Co(hmt)2(SCN)2(H2O)2][Co(SCN)2(H2O)4](H2O)2, 测试了该化合物在5~300 K范围内的变温磁化率.结果表明,其磁行为在测定的温度范围内遵守Curie-Weiss定律, 金属离子之间存在弱的反铁磁偶合.

  5. In situ Immobilization of Copper Nanoparticles on Polydopamine Coated Graphene Oxide for H2O2 Determination

    OpenAIRE

    Yingzhu Liu; Yanwei Han; Rongsheng Chen; Haijun Zhang; Simin Liu; Feng Liang

    2016-01-01

    Nanostructured electrochemical sensors often suffer from irreversible aggregation and poor adhesion to the supporting materials, resulting in reduced sensitivity and selectivity over time. We describe a versatile method for fabrication of a H2O2 sensor by immobilizing copper nanoparticles (Cu NPs; 20 nm) on graphene oxide (GO) sheets via in-situ reduction of copper(II) on a polydopamine (PDA) coating on a glassy carbon electrode. The PDA film with its amino groups and catechol groups acts as ...

  6. Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

    Science.gov (United States)

    Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.

    2016-11-01

    We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we have detected 14 new H2O emission lines. These include five 321-312ortho-H2O lines (Eup/k = 305 K) and nine J = 2 para-H2O lines, either 202-111(Eup/k = 101 K) or 211-202(Eup/k = 137 K). The apparent luminosities of the H2O emission lines are μLH2O 6-21 × 108 L⊙ (3 integrated line fluxes ranging from 4-15 Jy km s-1. We have also observed CO emission lines using EMIR on the IRAM 30 m telescope in seven sources (most of those have not yet had their CO emission lines observed). The velocity widths for CO and H2O lines are found to be similar, generally within 1σ errors in the same source. With almost comparable integrated flux densities to those of the high-J CO line (ratios range from 0.4 to 1.1), H2O is found to be among the strongest molecular emitters in high-redshift Hy/ULIRGs. We also confirm our previously found correlation between luminosity of H2O (LH2O) and infrared (LIR) that LH2O LIR1.1-1.2, with ournew detections. This correlation could be explained by a dominant role of far-infrared pumping in the H2O excitation. Modelling reveals that the far-infrared radiation fields have warm dust temperature Twarm 45-75 K, H2O column density per unit velocity interval NH2O /ΔV ≳ 0.3 × 1015 cm-2 km-1 s and 100 μm continuum opacity τ100> 1 (optically thick), indicating that H2O is likely to trace highly obscured warm dense gas. However, further observations of J ≥ 4 H2O lines are needed to better constrain the continuum optical depth and other physical conditions of the molecular gas and dust. We have also detected H2O+ emission in three sources. A tight correlation between LH2O and LH2O+ has been found in galaxies from low to high

  7. Preparation and Crystal Structure of a Rare-earth Salt Based on the Decavanadate (V10O286-):[Y(H2O)8]2[V10O28]·9H2O

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The salt, [Y(H2O)8]2[V10O28]·9H2O, contains two discrete water-groups coordinated Y(III) cations, an isopoly complex ion, decavanadate (V10O286-) and nine additional water molecules, which are combined together by static electric forces and hydrogen bonds. The Y3+ is eight-coor- dinated with a square antiprism geometry. The single-crystal X-ray analysis reveals that the crystal crystallizes in triclinic, space group P with a = 9.1454 (18), b = 10.007(2), c = 12.772(3)(A),α = 68.86(3), β = 77.50(3),γ = 89.23(3)°, V = 1061.7(4)(A)3 and Z = 1.

  8. Nanoporous magnets of chiral and racemic [{Mn(HL)}2Mn{Mo(CN)7}2] with switchable ordering temperatures (TC = 85 K 106 K) driven by H2O sorption (L = N,N-dimethylalaninol).

    Science.gov (United States)

    Milon, Julie; Daniel, Marie-Christine; Kaiba, Abdellah; Guionneau, Philippe; Brandès, Stéphane; Sutter, Jean-Pascal

    2007-11-14

    Molecule-based solids represent a rare opportunity to combine, adjust, and interrelate structural and physical functionalities to develop multifunctional materials. Here we report on a series of porous supramolecular magnets whose magnetic properties are related to their sorption state. A family of magnets of the formula [{Mn(HL)(H2O)}2Mn{Mo(CN)7}2].2H2O have been obtained by assembling the heptacyano-metalate building unit {Mo(CN)7}4- with Mn(II) in the presence of protonated N,N-dimethylalaninol (L) as ligand, the latter being either as a racemic mixture or as a chiral R- or S-enantiomer. The resulting magnets possess an open framework structure and exhibit a TC with a switching behavior (TC = 85 K 106 K) as a function of the hydration state. Moreover, chiral magnets are formed with the optically active ligands. The H2O and gas (N2, CO2, CO) sorption features, the magnetic behavior of both the hydrated and dehydrated magnets, and the crystal structures of the hydrated chiral (S) and racemic magnets are described.

  9. Tetra-μ-aqua-octaaquabis(μ-4-chloropyridine-2,6-dicarboxylatobis(4-chloropyridine-2,6-dicarboxylatotricobalt(IIdisodium(I bis[triaquabis(4-chloropyridine-2,6-dicarboxylatocobalt(II] hexahydrate

    Directory of Open Access Journals (Sweden)

    LaMaryet Moody

    2008-01-01

    Full Text Available The title compound, [Co3Na2(C7H2ClNO44(H2O12][Co(C7H2ClNO4(H2O3]2·6H2O, consists of a centrosymmetric dimer of [CoII(dipicCl2]2− complex dianions [dipicCl is 4-chloropyridine-2,6-dicarboxylate] bridged by an [Na2CoII(H2O12]4+ tetracationic cluster, two independent [Co(dipicCl(H2O3] complexes, and six water molecules of crystallization. The metals are all six-coordinate with distorted octahedral geometries. The [CoII(dipicCl(H2O3] complexes are neutral, with one tridentate ligand and three water molecules. The [CoII(dipicCl2]2− complexes each have two tridentate ligands. The [Na2CoII(H2O12]4+ cluster has a central CoII ion which is coordinated to six water molecules and lies on a crystallographic inversion center. Four of the water molecules bridge to two sodium ions, each of which have three other water molecules coordinated along with an O atom from the [CoII(dipicCl2]2− complex. In the crystal structure, the various units are linked by O—H...O hydrogen bonds, forming a three-dimensional network. Two water molecules are disordered equally over two positions.

  10. Ro-vibrational spectrum of H2O-Ne in the ν2 H2O bending region: A combined ab initio and experimental investigation

    Science.gov (United States)

    Liu, Xunchen; Hou, Dan; Thomas, Javix; Li, Hui; Xu, Yunjie

    2016-12-01

    High resolution ro-vibrational transitions of the H2O-Ne complex in the ν2 bending region of H2O at 6 μm have been measured using a rapid scan infrared spectrometer based on an external cavity quantum cascade laser and an astigmatic multipass optical cell. To aid the spectral assignment, a four-dimension potential energy surface of H2O-Ne which depends on the intramolecular bending coordinate of the H2O monomer and the three intermolecular vibrational coordinates has been constructed and the rovibrational transitions have been calculated. Three ortho and two para H2O-20Ne bands have been identified from the experimental spectra. Some weaker transitions belonging to H2O-22Ne have also been identified experimentally. Spectroscopic fits have been performed for both the experimental and theoretical transition frequencies using a simple pseudo-diatomic Hamiltonian including both Coriolis coupling and Fermi resonance terms. The experimental and theoretical spectroscopic constants thus obtained have been compared. Further improvements needed in the potential energy surface and the related spectral simulation have been discussed.

  11. Crystallization of Two Cyanide-bridged Bimetallic Complexes [LN(DMSO)2(H2O)3Co(CN)6]·H2O (LN = Pr or Nd, DMSO = Dimethylsulfoxide)

    Institute of Scientific and Technical Information of China (English)

    梁淑惠; 车云霞; 郑吉民

    2005-01-01

    Two diadochy cyanide-bridged bimetallic complexes [Pr(DMSO)2(H2O)3Co(CN)6] ·H2O 1 and [Nd(DMSO)2(H2O)3Co(CN)6]·H2O 2 have been synthesized, and their crystal structures were determined by single-crystal X-ray diffraction methods. Crystal data for 1: monoclinic, space group P21/c, a = 7.692(2), b = 30.791(10), c = 9.131(3) (A), β =100.645(5)o, V = 2125.4(11) (A)3, Z = 4, the final R = 0.0422 and Wr = 0.0904 for 3484 observed reflections with I > 2σ(I); and those for 2: monoclinic, space group P21/c, a = 7.692(3), b = 30.902(11), c = 9.152(3) (A), β = 100.665(5)o, V = 2137.8(13) (A)3, Z = 4, the final R = 0.0515 and wR = 0.0906 for 3268 observed reflections with I > 2σ(I). The LN atoms are linked to the Co atoms by cyanide bridging, forming a two-dimensional gridding structure. The LN3+ ions are both eight-coordinated by three cyano nitrogen and five oxygen atoms of two DMSO and three water molecules. The X-ray single-crystal structure analysis shows that the unbridged cyanide ligands between the closest layers interact with the coordinated water molecules through hydrogen bonds to connect the two layers. Therefore, the molecular structure is a 3D hydrogen-bonded network derived from LNCo chains.

  12. RADIATION DEGRADATION OF CHITOSAN IN THE PRESENCE OF H2O2

    Institute of Scientific and Technical Information of China (English)

    Yi-hong Lu; Gen-shuan Wei; Jing Peng

    2004-01-01

    In order to obtain the chitosan oligomers, chitosan was irradiated in the solid state with and without H2O2 as a radiation degradation sensitizer, respectively. At room temperature, the viscosity average-molecular weight (Mη) of chitosan was decreased from 1.6 × 106 to 2.2 × 105 at an absorbed dose of 72 kGy without H2O2, and decreased to 2.7 × 104 at 2 kGy in the presence of an appropriate H2O2 content. In addition, the radiation degradation rate of chitosan containing 38.2wt%H2O2 is 59 times higher than that in the solid state without H2O2. FT-IR analysis suggests that there is no obvious change in the chemical structure of irradiated chitosan with and without H2O2 at a dose below 20 kGy, compared with unirradiated chitosan. On the other hand, the degree of deacetylation (DD) of irradiated chitosan in the studied dose range changed slightly, while DD of irradiated chitosan with H2O2 increased significantly. The XRD pattern indicates that the irradiated chitosan with H2O2 has more perfect crystalline structure than unirradiated chitosan. Therefore, it could be expected that irradiation of chitosan using H2O2 as a sensitizer would be a very effective method to prepare low molecular weight chitosan,because of its feasibility and benignancy to environment.

  13. Cellular responses to H(2)O(2) and bleomycin-induced oxidative stress in L6C5 rat myoblasts.

    Science.gov (United States)

    Caporossi, Daniela; Ciafrè, Silvia Anna; Pittaluga, Monica; Savini, Isabella; Farace, Maria Giulia

    2003-12-01

    In muscle cells, reactive oxygen species (ROS) are continually generated. It is believed that these molecules have a well-established role as physiological modulators of skeletal muscle functions, ranging from development to metabolism and from blood flow to contractile functions. Moreover, ROS may contribute to the development of muscle fatigue, inflammation, and degeneration, and may be implicated in many muscle diseases. The aim of the present study was to verify the role of short or prolonged exposure to oxidative stress, generated by different concentrations of H(2)O(2), on growth, chromosomal aberrations, and apoptosis induced in cultured L6C5 rat muscle cells used as model for myoblasts. Our results indicate that, in L6C5 cells, reactive oxygen intermediates (ROI) can activate distinct cell pathways leading to cell growth induction and development of resistant phenotype, or to chromosomal aberrations, cell cycle arrest, or cell death. The positive vs. negative effects of H(2)O(2)-altered redox potential in myoblasts are strictly related to the intensity of oxidative stress, likely depending on the types and number of cellular targets involved. Among these, DNA molecules appear to be very sensitive to breakage by H(2)O(2), although DNA damage is not directly responsible for ROI-induced apoptosis in L6C5 rat myoblasts.

  14. Ionizing Collisions of Electrons with Radical Species OH, H2 O2 and HO2; Theoretical Calculations

    Science.gov (United States)

    Joshipura, K. N.; Pandya, S. H.; Vaishnav, B. G.; Patel, U. R.

    2016-05-01

    In this paper we present our calculated total ionization cross sections (TICS) of electron impact on radical targets OH, H2 O2 and HO2 at energies from threshold to 2000 eV. Reactive species such as these pose difficulties in measurements of electron scattering cross sections. No measured data have been reported in this regard except an isolated TICS measurement on OH radical, and hence the present work on the title radicals hold significance. These radical species are present in an environment in which water molecules undergo dissociation (neutral or ionic) in interactions with photons or electrons. The embedding environments could be quite diverse, ranging from our atmosphere to membranes of living cells. Ionization of OH, H2 O2 or HO2 can give rise to further chemistry in the relevant bulk medium. Therefore, it is appropriate and meaningful to examine electron impact ionization of these radicals in comparison with that of water molecules, for which accurate da are available. For the OH target single-centre scattering calculations are performed by starting with a 4-term complex potential, that describes simultaneous elastic plus inelastic scattering. TICS are obtained from the total inelastic cross sections in the complex scattering potential - ionization contribution formalism , a well established method. For H2 O2 and HO2 targets, we employ the additivity rule with overlap or screening corrections. Detailed results will be presented in the Conference.

  15. The chain structure of [Ni(C4H2O4(C12H8N2(H2O]n with different types of fumarate bridging

    Directory of Open Access Journals (Sweden)

    Anna Uhrinová

    2012-02-01

    Full Text Available Using modified solvothermal conditions (longer cooling time, beside previously characterized dark-green crystals of [Ni(C4H2O4(C12H8N2] (main product, a few light-green crystals of the polymeric title compound, catena-poly[[aqua(1,10-phenanthroline-κ2N,N′nickel(II]-μ-fumarato-κ2O:O′-[aqua(1,10-phenanthroline-κ2N,N′nickel(II]-μ-fumarato-κ4O,O′:O′′,O′′′], [Ni(C4H2O4(C12H8N2(H2O]n were isolated. Its crystal structure is made up from zigzag chains, propagating in [001], in which the Ni2+ ions are linked alternatively by μ2-fumarato and bis-chelating fumarato bridging ligands. The Ni2+ ion is coordinated in a deformed octahedral geometry by one chelating 1,10-phenanthroline ligand, one aqua ligand in a cis position with regard to both N-donor atoms and by two different fumarato ligands, each residing with its central C=C bond on an inversion centre, occupying the remaining coordination sites in a fac fashion. The chains thus formed are linked by O—H...O hydrogen bonds and π–π interactions between the aromatic rings of the phenanthroline ligands with a shortest ring centroid separation of 3.4787 (10 Å.

  16. Synthesis and thermal decomposition of Zn(tda)H2O [tda = S(CH(2)COO)2(2-)].

    Science.gov (United States)

    Wu, Ming-Cheng; Lee, Chi-Shen

    2006-11-27

    A novel two-dimensional coordination polymer Zn(tda)H2O [tda = S(CH(2)COO)2(2-)] was synthesized under hydrothermal conditions. The compound crystallized in monoclinic space group P2(1) with a = 16.4154(17) A, b = 5.2133(6) A, c = 16.4210(17) A, beta = 114.165(2) degrees , V = 1282.1(2) A3, and Z = 8. The structure features two-dimensional, noncentrosymmetric networks with a pseudohexagonal network of Zn2+ coordinated by tda and water molecules. Zn(tda)H2O decomposed at T > 300 degrees C to form a ZnO sponge with a surface area approximately 40 m2/g, which makes it an attractive precursor for nanoporous ZnO.

  17. Spontaneous Emission Between - and Para-Levels of Water-Ion H_2O^+

    Science.gov (United States)

    Tanaka, Keiichi; Harada, Kensuke; Nanbu, Shinkoh; Oka, Takeshi

    2012-06-01

    Nuclear spin conversion interaction of water ion, H_2O^+, has been studied to derive spontaneous emission lifetime between ortho- and para-levels. H_2O^+ is a radical ion with the ^2B_1 electronic ground state. Its off-diagonal electron spin-nuclear spin interaction term, Tab(S_aΔ I_b + S_bΔ I_a), connects para and ortho levels, because Δ I = I_1 - I_2 has nonvanishing matrix elements between I = 0 and 1. The mixing by this term with Tab = 72 MHz predicted by ab initio theory in the MRD-CI/Bk level, is many orders of magnitude larger than for closed shell molecules because of the large magnetic interaction due to the un-paired electron. Using the molecular constants reported by Mürtz et al. by FIR-LMR, we searched for ortho and para coupling channels below 1000 cm-1 with accidental near degeneracy between para and ortho levels. For example, hyperfine components of the 42,2(ortho) and 33,0(para) levels mix by 1.2 × 10-3 due to their near degeneracy (Δ E = 0.417 cm-1), and give the ortho-para spontaneous emission lifetime of about 0.63 year. The most significant low lying 10,1(para) and 11,1(ortho) levels, on the contrary, mix only by 8.7 × 10-5 because of their large separation (Δ E = 16.267 cm-1) and give the spontaneous emission lifetime from 10,1(para) to 00,0(ortho) of about 100 year.These results qualitatively help to understand the observed high ortho- to para- H_2O^+ ratio of 4.8 ± 0.5 toward Sgr B2 but they are too slow to compete with the conversion by collision unless the number density of the region is very low (n ˜1 cm-3) or radiative temperature is very high (T_r > 100 K). M. Staikova, B. Engels, M. Peric, and S.D. Peyerimhoff, Mol. Phys. 80, 1485 (1993) P. Mürtz, L.R. Zink, K.M. Evenson, and J.M. Brown J. Chem. Phys. 109, 9744 (1998). LP. Schilke, et al., A&A 521, L11 (2010).

  18. Aqua{N-[1-(2-oxidophenylethylidene]-l-serinato}copper(II monohydrate

    Directory of Open Access Journals (Sweden)

    Qin-Long Peng

    2009-12-01

    Full Text Available In the title compound, [Cu(C11H11NO4(H2O]·H2O, each CuII ion is four-coordinated by one N and two O atoms from the tridentate Schiff base ligand, and by one O atom from the coordinated water molecule in a distorted square-planar geometry. Intermolecular O—H...O hydrogen bonds link complex molecules and solvent water molecules into flattened columns propagated in [100].

  19. Crystal structure of magnesium selenate heptahydrate, MgSeO4·7H2O, from neutron time-of-flight data

    Directory of Open Access Journals (Sweden)

    A. Dominic Fortes

    2014-09-01

    Full Text Available MgSeO4·7H2O is isostructural with the analogous sulfate, MgSO4·7H2O, consisting of isolated [Mg(H2O6]2+ octahedra and [SeO4]2− tetrahedra, linked by O—H...O hydrogen bonds, with a single interstitial lattice water molecule. As in the sulfate, the [Mg(H2O6]2+ coordination octahedron is elongated along one axis due to the tetrahedral coordination of the two apical water molecules; these have Mg—O distances of ∼2.10 Å, whereas the remaining four trigonally coordinated water molecules have Mg—O distances of ∼2.05 Å. The mean Se—O bond length is 1.641 Å and is in excellent agreement with other selenates. The unit-cell volume of MgSeO4·7H2O at 10 K is 4.1% larger than that of the sulfate at 2 K, although this is not uniform; the greater part of the expansion is along the a axis of the crystal.

  20. Approximate solutions of the Thomas-Fermi equation for molecules. II

    NARCIS (Netherlands)

    Brinkman, H.C.; Peperzak, B.

    1955-01-01

    The method of solving the Thomas-Fermi equation, developed in a previous paper 1), is applied to the H2O-molecule. The electronic density is calculated. A proof is given that the Thomas-Fermi method, or generally any method, which treats the electrons as a continuous cloud of electricity obeying the

  1. Photo-oxidative degradation of levafix navy in UV/H2O2 system%UV/H2O2光助氧化降解丽华实军蓝制衣染料

    Institute of Scientific and Technical Information of China (English)

    黄晓霞; 刘茹; 蔡邦宏

    2012-01-01

    The reaction determining parameters and the reaction kinetics of the photo-oxidative degradation of a dye Levafix Navy in the UV/H2O2 system haven been studied.The UV/H2O2 system is highly efficient in degradating Levafix Navy,i.e.,a small amount of H2O2 can degrade highly concentrated dye solution.Moreover,the UV photo-decomposition of the dye molecules is found to be concurrent with the photo-oxidative degradation,both of which are apparent first-order reactions.The former reaction has an activation energy of 9.71 kJ · mol-1 with a pre-exponential factor of 1.61 min-1,and the latter has an activation energy of 50.3 kJ ·mo1-1 with a pre-exponential factor of 3.88× 105 min-1,respectively.The dye degradation efficiency peaks when the initial pH of the dye solution is strongly basic( pH=12).%本文对UV/H2 O2光助氧化降解丽华实军蓝制衣染料的效果及其影响因素和动力学进行了研究.结果表明,UV/H2O2对丽华实军蓝染料废液具有很好的处理效果,用量少,处理浓度高,且在发生光助氧化降解的同时还伴随着光分解反应.UV/H2O2体系的光助氧化反应和UV体系的光分解反应均为表观一级反应,前者活化能9.71 kJ·mol-1,指前因子1.61 min-1,后者活化能50.3 kJ·mol-1,指前因子3.88×105 min-1.染料溶液初始pH为强碱性(pH=12)时染料降解率最大.

  2. Transcriptome analysis of H2O2-treated wheat seedlings reveals a H2O2-responsive fatty acid desaturase gene participating in powdery mildew resistance.

    Directory of Open Access Journals (Sweden)

    Aili Li

    Full Text Available Hydrogen peroxide (H(2O(2 plays important roles in plant biotic and abiotic stress responses. However, the effect of H(2O(2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H(2O(2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H(2O(2 treatment for 6 hour in one powdery mildew (PM resistant (PmA and two susceptible (Cha and Han lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H(2O(2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, 'transport' activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H(2O(2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H(2O(2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt. Eight of these genes were found to be co-regulated by H(2O(2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H(2O(2 stress and uncovers potential links between H(2O(2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat.

  3. Core-shell Prussian blue analogue molecular magnet Mn(1.5)[Cr(CN)6]·mH2O@Ni(1.5)[Cr(CN)6]·nH2O for hydrogen storage.

    Science.gov (United States)

    Bhatt, Pramod; Banerjee, Seemita; Anwar, Sharmistha; Mukadam, Mayuresh D; Meena, Sher Singh; Yusuf, Seikh M

    2014-10-22

    Core-shell Prussian blue analogue molecular magnet Mn1.5[Cr(CN)6]·mH2O@Ni1.5[Cr(CN)6]·nH2O has been synthesized using a core of Mn1.5[Cr(CN)6]·7.5H2O, surrounded by a shell of Ni1.5[Cr(CN)6]·7.5H2O compound. A transmission electron microscopy (TEM) study confirms the core-shell nature of the nanoparticles with an average size of ∼25 nm. The core-shell nanoparticles are investigated by using x-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and elemental mapping, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. The Rietveld refinement of the XRD pattern reveals that the core-shell compound has a face-centered cubic crystal structure with space group Fm3m. The observation of characteristic absorption bands in the range of 2000-2300 cm(-1) in IR spectra corresponds to the CN stretching frequency of Mn(II)/Ni(II)-N≡C-Cr(III) sequence, confirming the formation of Prussian blue analogues. Hydrogen absorption isotherm measurements have been used to investigate the kinetics of molecular hydrogen adsorption into core-shell compounds of the Prussian blue analogue at low temperature conditions. Interestingly, the core-shell compound shows an enhancement in the hydrogen capacity (2.0 wt % at 123 K) as compared to bare-core and bare-shell compounds. The hydrogen adsorption capacity has been correlated with the specific surface area and TGA analysis of the core-shell compound. To the best of our knowledge, this is the first report on the hydrogen storage properties of core-shell Prussian blue analogue molecular magnet that could be useful for hydrogen storage applications.

  4. H2O incorporation in the phosphorene/a-SiO2 interface: a first-principles study

    Science.gov (United States)

    Scopel, Wanderlã L.; Souza, Everson S.; Miwa, R. H.

    2017-02-01

    Based on first-principles calculations, we investigate (i) the energetic stability and electronic properties of single-layer phosphorene (SLP) adsorbed on an amorphous SiO2 surface (SLP/a-SiO2), and (ii) the further incorporation of water molecules at the phosphorene/a-SiO2 interface. In (i), we find that the phosphorene sheet binds to a-SiO2 through van der Waals interactions, even in the presence of oxygen vacancies on the surface. The SLP/a-SiO2 system presents a type-I band alignment, with the valence (conduction) band maximum (minimum) of the phosphorene lying within the energy gap of the a-SiO2 substrate. The structure and the surface-potential corrugations promote the formation of electron-rich and electron-poor regions on the phosphorene sheet and at the SLP/a-SiO2 interface. Such charge density puddles are strengthened by the presence of oxygen vacancies in a-SiO2. In (ii), because of the amorphous structure of the surface, we consider a number of plausible geometries for H2O embedded in the SLP/a-SiO2 interface. There is an energetic preference for the formation of hydroxyl (OH) groups on the a-SiO2 surface. Meanwhile, in the presence of oxygenated water or interstitial oxygen in the phosphorene sheet, we observe the formation of metastable OH bonded to the phosphorene, and the formation of energetically stable P-O-Si chemical bonds at the SLP/a-SiO2 interface. Further x-ray absorption spectra simulations are performed, which aim to provide additional structural/electronic information on the oxygen atoms forming hydroxyl groups or P-O-Si chemical bonds at the interface region.

  5. Synthesis and structure of decaaqua-hexasodium-calcium bis-nitrilotris(methylenephosphonate) bis(hexaaquasodium) tetrahydrate [CaNa6{NH(CH2PO3)3}2(H2O)10][Na(H2O)6]2 · 4H2O

    Science.gov (United States)

    Somov, N. V.; Chausov, F. F.; Zakirova, R. M.

    2017-05-01

    The product of the reaction of tetrasodium nitrilotris(methylenephosphonate) Na4H(NH(CH2PO3)3) with Ca(OH)2 having the formula [CaNa6{NH(CH2PO3)3}2(H2O)10][Na(H2O)6]2 · 4H2O (sp. gr. P21/ c, Z = 2, a = 12.0579(4) Å, b = 10.4569(3) Å, c = 19.9346(4) Å, β = 95.355(2)°) was synthesized and characterized. The complex anion consists of a ring composed of six hydrate-bridged Na atoms. The cavity of the anion incorporates a Ca atom coordinated by two phosphonate ligands in a distorted octahedral geometry. Each of the two complex cations contains a sodium ion octahedrally coordinated by six water molecules. The crystal packing consists of infinite ribbons of the complex anions, which are linked by hydrate bridges to form layers alternating with layers of the complex cations and interlayers composed of disordered water molecules of solvation.

  6. Crystal structures of {[Cu(Lpn2][Fe(CN5(NO]·H2O}n and {[Cu(Lpn2]3[Cr(CN6]2·5H2O}n [where Lpn = (R-propane-1,2-diamine]: two heterometallic chiral cyanide-bridged coordination polymers

    Directory of Open Access Journals (Sweden)

    Olha Sereda

    2015-04-01

    Full Text Available The title compounds, catena-poly[[[bis[(R-propane-1,2-diamine-κ2N,N′]copper(II]-μ-cyanido-κ2N:C-[tris(cyanido-κC(nitroso-κNiron(III]-μ-cyanido-κ2C:N] monohydrate], {[Cu(Lpn2][Fe(CN5(NO]·H2O}n, (I, and poly[[hexa-μ-cyanido-κ12C:N-hexacyanido-κ6C-hexakis[(R-propane-1,2-diamine-κ2N,N′]dichromium(IIItricopper(II] pentahydrate], {[Cu(Lpn2]3[Cr(CN6]2·5H2O}n, (II [where Lpn = (R-propane-1,2-diamine, C3H10N2], are new chiral cyanide-bridged bimetallic coordination polymers. The asymmetric unit of compound (I is composed of two independent cation–anion units of {[Cu(Lpn2][Fe(CN5(NO]} and two water molecules. The FeIII atoms have distorted octahedral geometries, while the CuII atoms can be considered to be pentacoordinate. In the crystal, however, the units align to form zigzag cyanide-bridged chains propagating along [101]. Hence, the CuII atoms have distorted octahedral coordination spheres with extremely long semicoordination Cu—N(cyanido bridging bonds. The chains are linked by O—H...N and N—H...N hydrogen bonds, forming two-dimensional networks parallel to (010, and the networks are linked via N—H...O and N—H...N hydrogen bonds, forming a three-dimensional framework. Compound (II is a two-dimensional cyanide-bridged coordination polymer. The asymmetric unit is composed of two chiral {[Cu(Lpn2][Cr(CN6]}− anions bridged by a chiral [Cu(Lpn2]2+ cation and five water molecules of crystallization. Both the CrIII atoms and the central CuII atom have distorted octahedral geometries. The coordination spheres of the outer CuII atoms of the asymmetric unit can be considered to be pentacoordinate. In the crystal, these units are bridged by long semicoordination Cu—N(cyanide bridging bonds forming a two-dimensional network, hence these CuII atoms now have distorted octahedral geometries. The networks, which lie parallel to (10-1, are linked via O—H...O, O—H...N, N—H...O and N—H...N hydrogen bonds involving all five non

  7. A Search for Submillimeter H2O Masers in Active Galaxies: The Detection of 321 GHZ H2O Maser Emission in NGC 4945

    Science.gov (United States)

    Hagiwara, Yoshiaki; Horiuchi, Shinji; Doi, Akihiro; Miyoshi, Makoto; Edwards, Philip G.

    2016-08-01

    We present further results of a search for extragalactic submillimeter H2O masers using the Atacama Large Millimeter/submillimeter Array (ALMA). The detection of a 321 GHz H2O maser in the nearby type 2 Seyfert galaxy, the Circinus galaxy, has previously been reported, and here the spectral analysis of four other galaxies is described. We have discovered H2O maser emission at 321 GHz toward the center of NGC 4945, a nearby type 2 Seyfert. The maser emission shows Doppler-shifted velocity features with velocity ranges similar to those of the previously reported 22 GHz H2O masers however, the non-contemporaneous observations also show differences in velocity offsets. The subparsec-scale distribution of the 22 GHz H2O masers revealed by earlier very long baseline interferometry observations suggests that the submillimeter masers could arise in an edge-on rotating disk. The maser features remain unresolved by the synthesized beam of ˜0.″54 (˜30 pc) and are located toward the 321 GHz continuum peak within errors. A marginally detected (3σ) high-velocity feature is redshifted by 579 km {{{s}}}-1 with respect to the systemic velocity of the galaxy. Assuming that this feature is real and arises from a Keplerian rotating disk in this galaxy, it is located at a radius of ˜0.020 pc (˜1.5 × 105 Schwarzschild radii), which would enable molecular material closer to the central engine to be probed than the 22 GHz H2O masers. This detection confirms that submillimeter H2O masers are a potential tracer of the circumnuclear regions of active galaxies, which will benefit from higher angular resolution studies with ALMA.

  8. Crystal structures of hydrates of simple inorganic salts. III. Water-rich aluminium halide hydrates: AlCl3 · 15H2O, AlBr3 · 15H2O, AlI3 · 15H2O, AlI3 · 17H2O and AlBr3 · 9H2O.

    Science.gov (United States)

    Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang

    2014-09-01

    Water-rich aluminium halide hydrate structures are not known in the literature. The highest known water content per Al atom is nine for the perchlorate and fluoride. The nonahydrate of aluminium bromide, stable pentadecahydrates of aluminium chloride, bromide and iodide, and a metastable heptadecahydrate of the iodide have now been crystallized from low-temperature solutions. The structures of these hydrates were determined and are discussed in terms of the development of cation hydration spheres. The pentadecahydrate of the chloride and bromide are isostructural. In AlI(3) · 15H2O, half of the Al(3+) cations are surrounded by two complete hydration spheres, with six H2O in the primary and 12 in the secondary. For the heptadecahydrate of aluminium iodide, this hydration was found for every Al(3+).

  9. A combined spectroscopic and theoretical study of propofol.(H2O)3

    Science.gov (United States)

    León, Iker; Cocinero, Emilio J.; Millán, Judith; Rijs, Anouk M.; Usabiaga, Imanol; Lesarri, Alberto; Castaño, Fernando; Fernández, José A.

    2012-08-01

    Propofol (2,6-di-isopropylphenol) is probably the most widely used general anesthetic. Previous studies focused on its complexes containing 1 and 2 water molecules. In this work, propofol clusters containing three water molecules were formed using supersonic expansions and probed by means of a number of mass-resolved laser spectroscopic techniques. The 2-color REMPI spectrum of propofol.(H2O)3 contains contributions from at least two conformational isomers, as demonstrated by UV/UV hole burning. Using the infrared IR/UV double resonance technique, the IR spectrum of each isomer was obtained both in ground and first excited electronic states and interpreted in the light of density functional theory (DFT) calculations at M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels. The spectral analysis reveals that in both isomers the water molecules are forming cyclic hydrogen bond networks around propofol's OH moiety. Furthermore, some evidences point to the existence of isomerization processes, due to a complicated conformational landscape and the existence of multiple paths with low energy barriers connecting the different conformers. Such processes are discussed with the aid of DFT calculations.

  10. Secondary ion emission from CO2-H2O ice irradiated by energetic heavy ions: Part I. Measurement of the mass spectra

    Science.gov (United States)

    Farenzena, L. S.; Collado, V. M.; Ponciano, C. R.; da Silveira, E. F.; Wien, K.

    2005-05-01

    Secondary ion mass spectrometry is used to investigate ion emission from a frozen-gas mixture (T = 80-90 K) of CO2 and H2O bombarded by MeV nitrogen ions and by 252Cf fission fragments (FF). The aim of the experiments is to produce organic molecules in the highly excited material around the nuclear track and to detect them in the flux of sputtered particles. Such sputter processes are known to occur at the icy surfaces of planetary or interstellar objects. Time-of-flight (TOF) mass spectrometry is employed to identify the desorbed ions. Mass spectra of positive and negative ions were taken for several molecular H2O/CO2 ratios. In special, positive ions induced by MeV nitrogen beam were analyzed for 9 and 18% H2O concentrations of the CO2-H2O ice and negative ions for ~5% H2O. The ion peaks are separated to generate exclusive the spectra of CO2 specific ions, H2O specific ions and hybrid molecular ions, the latter ones corresponding to ions that contain mostly H and C atoms. In the mass range from 10 to 320 u, the latter exhibits 35 positive and 58 negative ions. The total yield of the positive ions is 0.35 and 0.57 ions/impact, respectively, and of negative ions 0.066 ions/impact. Unexpected effects of secondary ion sputtering yields on H2O/CO2 ratio are attributed to the influence of water molecules concentration on the ionization process.

  11. Hydrothermal Synthesis and Structure of a Mixed-valence Polyoxotungstate Decorated by Copper(I) Coordination Group, [Cu(en)2H2O]2[{Cu(en)2}HPW12O40]·2H2O

    Institute of Scientific and Technical Information of China (English)

    LI Zhen; LIN Bi-Zhou; HAN Guo-Hua; GENG Feng; LIU Pei-De

    2005-01-01

    A complex [Cu(en)2H2O]2[{Cu(en)2}HPW12O40]·2H2O (C12H57Cu3N12O44PW12, Mr = 3501.49) has been synthesized under hydrothermal conditions and its crystal structure was determined by X-ray diffraction.It crystallizes in the orthorhombic system, space group Pbca with a = 21.680(4), b = 20.680(4), c = 26.120(5) (A), V = 11711(4) (A)3, Dc = 3.972 g/cm3, Z = 8, μ(MoKa) = 24.661 mm-1, F(000) = 12440, the final R = 0.0527 and wR = 0.1416 for 11527 observed reflec- tions with I > 2σ(I).The crystal structure is composed of [{Cu(en)2}HPW12O40]2- anions, discrete [Cu(en)2H2O]+ complex cations and crystal water molecules, which are held together into a three- dimensional network through hydrogen-bonding interactions.The anionic [{Cu(en)2}HPW12O40]2- is formed by the mixed valance {HPWVI11WVO40}3- Keggin unit covalently linked by a {Cu(en)2}+ group.

  12. Synthesis, Structure, Thermal and Magnetic Properties of a New Open-framework Borophosphate: NH4Mn(H2O)2BP2O8·H2O

    Institute of Scientific and Technical Information of China (English)

    SHI,Heng-Zhen; CHANG,Jia-Zhong; TANG-BO,HeJin; DING,Han-Ming; SHAN,Yong-Kui

    2006-01-01

    Using new template agent, a new borophosphate compound, NH4Mn(H2O)2BP2Os·H2O was hydrothermally prepared and structurally characterized. It crystallizes in a hexagonal space group P6122 with lattice parameters a=0.9652(2) nm, c=1.5792(5) nm, V=1.2740(5) nm3 and Z=6. The structure has a three-dimensional open-frame work with borophosphate helical ribbons 1∞{[BP2O8]3-} and MnO4(H2O)2 octahedra. The water molecules are positioned inside the helical channels. Very interestingly, the ammonium ions are located outside the loop of the free helical ribbons via the strong hydrogen bonds, which is different from the borophosphate analogue reported.The magnetization of the title compound is paramagnetic down to 5 K of the Curie-Weiss type within the measured range of 5-300 K with θ= -7.3 K, indicative of very weak antiferromagnetic interactions. The thermal decomposition of the compound was also described.

  13. Irradiation of pyrimidine in pure H2O ice with high-energy ultraviolet photons.

    Science.gov (United States)

    Nuevo, Michel; Chen, Yu-Jung; Hu, Wei-Jie; Qiu, Jun-Ming; Wu, Shang-Ruei; Fung, Hok-Sum; Chu, Ching-Chi; Yih, Tai-Sone; Ip, Wing-Huen; Wu, C-Y Robert

    2014-02-01

    The detection of nucleobases, the informational subunits of DNA and RNA, in several meteorites suggests that these compounds of biological interest were formed via astrophysical, abiotic processes. This hypothesis is in agreement with recent laboratory studies of irradiation of pyrimidine in H2O-rich ices with vacuum UV photons emitted by an H2-discharge lamp in the 6.9-11.3 eV (110-180 nm) range at low temperature, shown to lead to the abiotic formation of several compounds including the nucleobases uracil, cytosine, and thymine. In this work, we irradiated H2O:pyrimidine ice mixtures under astrophysically relevant conditions (14 K, ≤10(-9) torr) with high-energy UV photons provided by a synchrotron source in three different ranges: the 0(th) order light (4.1-49.6 eV, 25-300 nm), the He i line (21.2 eV, 58.4 nm), and the He ii line (40.8 eV, 30.4 nm). The photodestruction of pyrimidine was monitored with IR spectroscopy, and the samples recovered at room temperature were analyzed with liquid and gas chromatographies. Uracil and its precursor 4(3H)-pyrimidone were found in all samples, with absolute and relative abundances varying significantly from one sample to another. These results support a scenario in which compounds of biological interest can be formed and survive in environments subjected to high-energy UV radiation fields.

  14. Lipid oxidation in human low-density lipoprotein induced by metmyoglobin/H2O2

    DEFF Research Database (Denmark)

    Witting, P K; Willhite, C A; Davies, Michael Jonathan

    1999-01-01

    Metmyoglobin (metMb) and H(2)O(2) can oxidize low-density lipoprotein (LDL) in vitro, and oxidized LDL may be atherogenic. The role of alpha-tocopherol (alpha-TOH) in LDL oxidation by peroxidases such as metMb is unclear. Herein, we show that during metMb/H(2)O(2)-induced oxidation of native LDL...

  15. Activity and Selectivity for O-2 Reduction to H2O2 on Transition Metal Surfaces

    DEFF Research Database (Denmark)

    Siahrostami, Samira; Verdaguer Casadevall, Arnau; Karamad, Mohammadreza;

    2013-01-01

    Industrially viable electrochemical production of H2O2 requires active, selective and stable electrocatalyst materials to catalyse the oxygen reduction reaction to H2O2. On the basis of density functional theory calculations, we explain why single site catalysts such as Pd/Au show improved select...

  16. Stability of globular proteins in H2O and D2O

    NARCIS (Netherlands)

    Efimova, Y. M.; Haemers, S.; Wierczinski, B.; Norde, W.; van Well, A. A.

    2007-01-01

    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the stabili

  17. A comparative study on removal of trace nitrobenzene in water by UV/H2O2 and UV/TiO2/H2O2%UV/H2O2和UV/TiO2/H2O2去除水中微量硝基苯的比较研究

    Institute of Scientific and Technical Information of China (English)

    尹菁菁; 张彭义; 孙莉

    2006-01-01

    研究比较了UV/H2O2和UV/TiO2/H2O2对水中微量硝基苯的降解效果,并考察了水中常见HCO-3和腐殖酸对硝基苯降解的影响.结果表明,薄膜状TiO2的存在对UV/H2O2降解硝基苯有显著的促进作用,在最佳H2O2投加量2.1 mg/L时,UV/TiO2/H2O2的反应速率常数比UV/H2O2高32.8%;2 min内UV/TiO2/H2O2对硝基苯的去除率达到80%以上.HCO-3和腐殖酸对硝基苯降解有很强的抑制作用,HCO-3和腐殖酸浓度分别为2 mmol/L和3.2 mg/L时,UV/TiO2/H2O2对硝基苯的反应速率常数分别下降84.6%和92.2%.

  18. Adsorption of CO2 and H2O on supported amine sorbents

    NARCIS (Netherlands)

    Veneman, R.; Zhao, W.; Li, Z.; Cai, N.; Brilman, D.W.F.

    2014-01-01

    In this work we have evaluated the H2O and CO2 adsorption characteristics of Lewatit VP OC 1065 in view of the potential application of solid sorbents in post combustion CO2 capture. Here we present single component adsorption isotherms for H2O and CO2 as well as co-adsorption experiments. It was co

  19. Adsorption of H2O and CO2 on supported amine sorbents

    NARCIS (Netherlands)

    Veneman, Rens; Frigka, Natalia; Zhao, Wenying; Li, Zhenshan; Kersten, Sascha; Brilman, Wim

    2015-01-01

    In this work the adsorption of H2O and CO2 on Lewatit VP OC 1065 was studied in view of the potential application of this sorbent in post combustion CO2 capture. Both CO2 and H2O were found to adsorb on the amine active sites present on the pore surface of the sorbent material. However, where the in

  20. Stability of globular proteins in H2O and in D2O

    NARCIS (Netherlands)

    Efimova, Y.M.; Haemers, S.; Wierczinsky, B.; Norde, W.; Well, van A.A.

    2007-01-01

    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the

  1. Stability of globular proteins in H2O and D2O

    NARCIS (Netherlands)

    Efimova, Y. M.; Haemers, S.; Wierczinski, B.; Norde, W.; van Well, A. A.

    2007-01-01

    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the

  2. Synthesis and Crystal Structure of a Novel 1D Chain-like Organic Inorganic Hybrid Rare Earth Derivative of Polyoxometalate: H0.5[Sm(H2O)6]0.25[Sm(H2O)5]0.25{[Sm(H2O)7][Sm(H2O)2- (DMSO)] [SiW11O39]}·4.5H2O

    Institute of Scientific and Technical Information of China (English)

    Jun Wei ZHAO; Jing Ping WANG; Jing Yang NIU

    2005-01-01

    A 1D chain-like organic-inorganic hybrid rare earth derivative of polyoxometalate (DMSO) and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction.The neighboring polyanionic units {[Sm(H2O)7][Sm(H2O)2(DMSO)][SiW11O39]}2- are bridged together to a 1D chain structure by means of [Sm(H2O)2(DMSO)]3+ ion.

  3. Poly[[diaquabis(μ3-maleato-κ4O1:O1′,O4:O4′dicopper(II] trihydrate

    Directory of Open Access Journals (Sweden)

    Gregory A. Farnum

    2008-08-01

    Full Text Available In the title compound, {[Cu2(C4H2O42(H2O2]·3H2O}n, CuII ions with square-pyramidal coordination are bridged by exotridentate maleate dianions into [Cu2(maleate2(H2O2]n layers coincident with the bc crystal plane. The interlamellar regions contain hydrogen-bonded cyclic water hexamers which facilitate layer stacking into a pseudo-three-dimensional crystal structure. The water hexamers themselves are formed by the operation of crystallographic inversion centers on sets of three crystallographically distinct water molecules of hydration.

  4. Search for sub-millimeter H2O masers in active galaxies - the detection of a 321 GHz H2O maser in NGC4945

    CERN Document Server

    Hagiwara, Yoshiaki; Doi, Akihiro; Miyoshi, Makoto; Edwards, Philip G

    2016-01-01

    We present further results of a search for extragalactic submillimeter H2O masers using the Atacama Large Millimeter/Submillimeter Array (ALMA). The detection of a 321 GHz H2O maser in the nearby Type 2 Seyfert galaxy, the Circinus galaxy, has previously been reported, and here the spectral analysis of four other galaxies is described. A 321 GHz H2O maser is newly detected toward the center of NGC 4945, a nearby Type 2 Seyfert. The maser shows Doppler-shifted velocity features with velocity ranges similar to those of the 22 GHz H2O maser, however the non-contemporaneous observations also show differences in velocity offsets. The sub-parsec-scale distribution of the 22 GHz H2O masers revealed by earlier VLBI (Very Long Baseline Interferometry) observations suggests that the submillimeter masers could arise in an edge-on rotating disk. The maser features remain unresolved at the synthesized beam of ~0.54 (~30 pc) and are located toward the 321 GHz continuum peak within errors. There is some evidence for a high-...

  5. A novel electrochemical biosensor for monitoring protein nitration damage affected by NaNO2/hemin/H2O2.

    Science.gov (United States)

    Tang, Yanjuan; Guo, Yanjie; Zhang, Lu; Cai, Jiye; Yang, Peihui

    2014-04-15

    A sensitive and facile electrochemical biosensor has been developed for monitoring the protein nitration damage affected by the nitro free radicals(NO2). The NO2 radicals is generated from hemin-catalyzed oxidation of nitrite (NO(-)2) in the presence of hydrogen peroxide (H2O2). In this work, nanocomposite films of graphene-gold nanoparticles (EG-AuNPs) were modified on the glassy carbon electrode by electropolymerization. Bovine serum albumin (BSA) was then further assembled on EG-AuNPs film through Au-S bond. The damage of BSA molecule was caused by the NO2 radicals which was generated from the NaNO2/hemin/H2O2 nitration reagent. The differential pulse voltammetry was used to detect the damage of BSA molecule. Fluorescence spectra and circular dichroism spectrum further confirmed the nitration damage of BSA. Moreover, the lowest concentration at which the BSA damage was detected is 28.9 µM NO(-)2 or H2O2, and the volume ratio of NO(-)2 and H2O2 was 1:1 in the hemin/NO(-)2/H2O2 nitration reagent. The results demonstrated that the proposed electrochemical method can be used to detect protein damage affected by nitration reagent. The developed electrochemical biosensor is envisioned to have promising applications in protein damage studies. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. [Theory study of the structures and IR of (C5H5N)n(H2O), (n = 1-2, m = 1-4) clusters].

    Science.gov (United States)

    Li, Xiao-Ming; Zhang, Lai-Bin; Zhou, Liu-Zhu; Kong, Xiang-He

    2014-07-01

    Using density functional theory, the possible geometrical structures of (C5H5N)n (H2O)m (n = 1-2, m = 1- 4) clusters were optimized at the B3LYP/6-311++G(d, p) level and the stable structures were attained. For the dimer formed between C5H5N and H2O, the calculation result shows that there is only one stable structure and the configuration of cluster formed through pi hydrogen bond (O-H...pi) interaction was not found. In order to study the stability of the clusters, the total energies and binding energies of the clusters were calculated at the same level of theory, and the result shows that the four-membered ring structures of water molecules in (C5H5N)n (H2O)4 (n = 1-2) clusters are more stable than structures of the triatomic ring of water molecules. The lowest energy structure of the C5H5N (H2O)4 cluster is more stable than the others and is probably a magic number structure by the analysis to the energy gap between HOMO and LUMO. At the end, the IR spectra of (C5H5N)n (H2O)m (n = 1-2, m = 1-4) clusters were analysed and the stronger peaks appearing in infrared spectra were assigned.

  7. Effects of H2O2 on Oxygen Supply in the Process of DCA Fermentation

    Institute of Scientific and Technical Information of China (English)

    黄英明; 焦鹏; 李书良; 华玉涛; 曹竹安

    2002-01-01

    Long chain dicarboxylic acid (DCA) produced by Candida tropicalis is produced in an aerobic viscous fermentation system. The gas-liquid transport resistance can be overcome and the oxygen supply can be increased by adding hydrogen peroxide (H2O2) to the fermentation system. This paper shows that H2O2 can not only enhance the oxygen supply but also change the metabolism by inducing cytochrome P450, the key enzyme of α, ω-oxidation. When C. tropicalis was cultivated in a 3-liter bioreactor using the combination of aeration and hydrogen peroxide feeding, the DCA yield increased about 10% except at the beginning of H2O2 feeding. The experiments showed that the maximum activities of P450 could be induced at 2 mmol*L-1 H2O2. By adding H2O2, the DCA yield in a 22-liter bioreactor was increased 25.3% to 153.9 g/L.

  8. H2 O2-induced higher order chromatin degradation: A novel mechanism of oxidative genotoxicity

    Indian Academy of Sciences (India)

    Gregory W Konat

    2003-02-01

    The genotoxicity of reactive oxygen species (ROS) is well established. The underlying mechanism involves oxidation of DNA by ROS. However, we have recently shown that hydrogen peroxide (H2O2), the major mediator of oxidative stress, can also cause genomic damage indirectly. Thus, H2O2 at pathologically relevant concentrations rapidly induces higher order chromatin degradation (HOCD), i.e. enzymatic excision of chromatin loops and their oligomers at matrix-attachment regions. The activation of endonuclease that catalyzes HOCD is a signalling event triggered specifically by H2O2. The activation is not mediated by an influx of calcium ions, but resting concentrations of intracellular calcium ions are required for the maintenance of the endonuclease in an active form. Although H2O2-induced HOCD can efficiently dismantle the genome leading to cell death, under sublethal oxidative stress conditions H2O2-induced HOCD may be the major source of somatic mutations.

  9. Detection of local H2O exposed at the surface of Ceres

    Science.gov (United States)

    Combe, Jean-Philippe; McCord, Thomas B.; Tosi, Federico; Ammannito, Eleonora; Carrozzo, Filippo Giacomo; De Sanctis, Maria Cristina; Raponi, Andrea; Byrne, Shane; Landis, Margaret E.; Hughson, Kynan H. G.; Raymond, Carol A.; Russell, Christopher T.

    2016-09-01

    The surface of dwarf planet Ceres contains hydroxyl-rich materials. Theories predict a water ice-rich mantle, and water vapor emissions have been observed, yet no water (H2O) has been previously identified. The Visible and InfraRed (VIR) mapping spectrometer onboard the Dawn spacecraft has now detected water absorption features within a low-illumination, highly reflective zone in Oxo, a 10-kilometer, geologically fresh crater, on five occasions over a period of 1 month. Candidate materials are H2O ice and mineral hydrates. Exposed H2O ice would become optically undetectable within tens of years under current Ceres temperatures; consequently, only a relatively recent exposure or formation of H2O would explain Dawn’s findings. Some mineral hydrates are stable on geological time scales, but their formation would imply extended contact with ice or liquid H2O.

  10. Search Directions for Direct H2O2 Synthesis Catalysts Starting from Au-12 Nanoclusters

    DEFF Research Database (Denmark)

    Grabow, Lars; Larsen, Britt Hvolbæk; Falsig, Hanne

    2012-01-01

    We present density functional theory calculations on the direct synthesis of H2O2 from H-2 and O-2 over an Au-12 corner model of a gold nanoparticle. We first show a simple route for the direct formation of H2O2 over a gold nanocatalyst, by studying the energetics of 20 possible elementary...... that the rate of H2O2 and H2O formation can be determined from a single descriptor, namely, the binding energy of oxygen (E-O). Our model predicts the search direction starting from an Au-12 nanocluster for an optimal catalyst in terms of activity and selectivity for direct H2O2 synthesis. Taking also stability...

  11. the Treatment Effect of γ-rays Combined with H2O2 on Sludge Filtrate

    Directory of Open Access Journals (Sweden)

    ZHANG Hao-jia

    2015-01-01

    Full Text Available The sludge filtrate was performed by 60Co γ-rays irradiation and additive of hydrogen peroxide (H2O2. Effects of initial pH, initial H2O2 concentration and radiation dose on irradiation degradation efficiency were studied by analyzing the change of CODCr、 UV/V is absorbance and turbidity before and after irradiation. The results indicated that the CODCr was removed more easily at the acidic condition under the same dose and initial H2O2 concentration. Gamma irradiation and H2O2 had a significant synergistic effect. When the absorbed dose was 18.75 kGy, the initial pH was 2 and the concentration of H2O2 was 2 mmol/L, the removal of CODCr and turbidity was 70.4% and 94.9%, respectively

  12. H2O vapor excitation in dusty AGB envelopes. A PACS view of OH 127.8+0.0

    CERN Document Server

    Lombaert, R; de Koter, A; Blommaert, J A D L; Royer, P; De Beck, E; de Vries, B L; Khouri, T; Min, M

    2015-01-01

    Context: AGB stars lose a large percentage of their mass in a dust-driven wind. This creates a circumstellar envelope, which can be studied through thermal dust emission and molecular emission lines. In the case of high mass-loss rates, this study is complicated by the high optical depths and the intricate coupling between gas and dust radiative transfer characteristics. An important aspect of the physics of gas-dust interactions is the strong influence of dust on the excitation of several molecules, including H2O. Aims: The dust and gas content of the envelope surrounding the high mass-loss rate OH/IR star OH 127.8+0.0, as traced by Herschel observations, is studied, with a focus on the H2O content and the dust-to-gas ratio. We report detecting a large number of H2O vapor emission lines up to J = 9 in the Herschel data, for which we present the measured line strengths. Methods: The treatments of both gas and dust species are combined using two numerical radiative transfer codes. The method is illustrated for...

  13. Theoretical study on structures and infrared spectroscopy of Cu2+(H2O)Ar n ( n = 1-4)

    Science.gov (United States)

    Song, Xiudan; Li, Shuxia; Jiang, Zishi; Zhang, Yongzhi

    2017-09-01

    The binding energy of Cu2+(H2O) is computed to be 98.4 kcal/mol and thus one-photon photodissociation is not possible in the 3400-3800 cm-1 (9.7-10.9 kcal/mol) region. To study whether the infrared photodissociation processes of Cu2+(H2O) can occur by multiple argon atoms tagging technique, density functional and CCSD(T) methods are used to investigate the geometries, OH stretching frequencies and the argon atom binding energies of Cu2+(H2O)Ar n ( n = 1-4) complexes. Various isomers are found resulting from the different coordination sites of argon atoms. The OH stretches in these complexes are shifted to lower frequencies than those of the free water molecule, and the corresponding vibrational red shifts are progressively smaller as more argon atom is added to Cu2+ while binding an argon atom to an OH site should lead to additional sizable red shift to the OH stretching vibrations.

  14. Hydrothermal synthesis of WO3·0.5H2O microtubes with excellent photocatalytic properties

    Science.gov (United States)

    Wang, Xiaozhou; Meng, Xiuqing; Zhong, Mianzeng; Wu, Fengmin; Li, Jingbo

    2013-10-01

    Pyrochlore WO3 microtubes were synthesized via a hydrothermal method for the first time. In this process, thiourea was employed to overcome the hydrogen bonds on the rim of WO3·0.5H2O and hydroxylamine hydrochloride was used as a viscosity regulator. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy observations revealed that large amounts of uniform single-crystal WO3·0.5H2O microtubes with diameters ranging from 100 to 300 nm and length of tens of micrometers were obtained. The thickness of the tube wall was about 40 nm. A possible rolling mechanism was proposed to explain the formation of the tubular structures, and the influence of thiourea and hydroxylamine hydrochloride on the uniform tubular morphology was discussed. The WO3·0.5H2O microtubes showed excellent photocatalytic activity toward the degradation of organic molecules such as RhB, which may find potential applications in the fields of photocatalysts, sensors and transistors.

  15. Photoelectron spectroscopy of the [glycine.(H2O)1,2]- clusters: Sequential hydration shifts and observation of isomers

    Science.gov (United States)

    Diken, Eric G.; Headrick, Jeffrey M.; Johnson, Mark A.

    2005-06-01

    The electron binding energies of the small hydrated amino acid anions, [glycine•(H2O)1,2]-, are determined using photoelectron spectroscopy. The vertical electron detachment energies (VDEs) are found to increase by approximately 0.12 eV with each additional water molecule such that the higher electron binding isomer of the dihydrate is rather robust, with a VDE value of 0.33 eV. A weak binding isomer of the dihydrate is also recovered, however, with a VDE value (0.14 eV) lower than that of the monohydrate. Unlike the situation in the smaller (n⩽13) water cluster anions, the [Gly•(H2O)n⩾6]- clusters are observed to photodissociate via water monomer evaporation upon photoexcitation in the O-H stretching region. We discuss this observation in the context of the mechanism responsible for the previously observed [S. Xu, M. Nilles, and K. H. Bowen, Jr., J. Chem. Phys. 119, 10696 (2003)] sudden onset in the cluster formation at [Gly•(H2O)5]-.

  16. In Vivo Monitoring of H2O2 with Polydopamine and Prussian Blue-coated Microelectrode.

    Science.gov (United States)

    Li, Ruixin; Liu, Xiaomeng; Qiu, Wanling; Zhang, Meining

    2016-08-02

    In vivo monitoring of hydrogen peroxide (H2O2) in the brain is of importance for understanding the function of both reactive oxygen species (ROS) and signal transmission. Producing a robust microelectrode for in vivo measurement of H2O2 is challenging due to the complex brain environment and the instability of electrocatalysts employed for the reduction of H2O2. Here, we develop a new kind of microelectrode for in vivo monitoring of H2O2, which is prepared by, first, electrodeposition of Prussian blue (PB) onto carbon nanotube (CNT) assembled carbon fiber microelectrodes (CFEs) and then overcoating of the CFEs with a thin membrane of polydopamine (PDA) through self-polymerization. Scanning electron microscopic and X-ray proton spectroscopic results confirm the formation of PDA/PB/CNT/CFEs. The PDA membrane enables PB-based electrodes to show high stability in both in vitro and in vivo studies and to stably catalyze the electrochemical reduction of H2O2. The microelectrode is selective for in vivo measurements of H2O2, interference-free from O2 and other electroactive species coexisting in the brain. These properties, along with good linearity, high biocompatibility, and stability toward H2O2, substantially enable the microelectrode to track H2O2 changes in vivo during electrical stimulation and microinfusion of H2O2 and drug, which demonstrates that the microelectrode could be well suited for in vivo monitoring of dynamic changes of H2O2 in rat brain.

  17. Photodegradation of amoxicillin by catalyzed Fe3+/H2O2 process

    Institute of Scientific and Technical Information of China (English)

    Xiaoming Li; Tingting Shen; Dongbo Wang; Xiu Yue; Xian Liu; Qi Yang; Jianbin Cao; Wei Zheng; Guangming Zeng

    2012-01-01

    Three oxidation processes of UV-Fe3+(EDTA)/H2O2 (UV:ultraviolet light; EDTA:ethylenediaminetetraacetic acid),UV-Fe3+/H2O2 and Fe3+/H2O2 were simultaneously investigated for the degradation of amoxicillin at pH 7.0.The results indicated that,100% amoxicillin degradation and 81.9% chemical oxygen demand (CODcr) removal could be achieved in the UV-Fe3+ (EDTA)/H2O2 process.The treatment efficiency of amoxicillin and CODcr removal were found to decrease to 59.0% and 43.0% in the UV-Fe3+/H2O2 process;39.6% and 31.3% in the Fe3+/H2O2 process.Moreover,the results of biodegradability (biological oxygen demand (BOD5)/CODCr ratio) revealed that the UV-Fe3+ (EDTA)/H2O2 process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45,compared with the cases of UV-Fe3+/H2O2 (0.25) and Fe3+/H2O2 (0.10) processes.Therefore,it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe3+/H2O2 process,enhancing the treatment efficiency.The degradation mechanisms were also investigated via UV-Vis spectra,and high performance liquid chromatography-mass spectra.The degradation pathway of amoxicillin was further proposed.

  18. Electrochemical H2O2 biosensor composed of myoglobin on MoS2 nanoparticle-graphene oxide hybrid structure.

    Science.gov (United States)

    Yoon, Jinho; Lee, Taek; Bapurao G, Bharate; Jo, Jinhee; Oh, Byung-Keun; Choi, Jeong-Woo

    2017-07-15

    In this research, the electrochemical biosensor composed of myoglobin (Mb) on molybdenum disulfide nanoparticles (MoS2 NP) encapsulated with graphene oxide (GO) was fabricated for the detection of hydrogen peroxide (H2O2). Hybrid structure composed of MoS2 NP and GO (GO@MoS2) was fabricated for the first time to enhance the electrochemical signal of the biosensor. As a sensing material, Mb was introduced to fabricate the biosensor for H2O2 detection. Formation and immobilization of GO@MoS2 was confirmed by transmission electron microscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and scanning tunneling microscopy. Immobilization of Mb, and electrochemical property of biosensor were investigated by cyclic voltammetry and amperometric i-t measurements. Fabricated biosensor showed the electrochemical signal enhanced redox current as -1.86μA at an oxidation potential and 1.95μA at a reduction potential that were enhanced relative to those of electrode prepared without GO@MoS2. Also, this biosensor showed the reproducibility of electrochemical signal, and retained the property until 9 days from fabrication. Upon addition of H2O2, the biosensor showed enhanced amperometric response current with selectivity relative to that of the biosensor prepared without GO@MoS2. This novel hybrid material-based biosensor can suggest a milestone in the development of a highly sensitive detecting platform for biosensor fabrication with highly sensitive detection of target molecules other than H2O2.

  19. Aqua(di-2-pyridylamine-kappa2N,N')(malonato-kappa2O,O')copper(II) monohydrate.

    Science.gov (United States)

    Youngme, Sujittra; Phatchimkun, Jaturong; Chaichit, Narongsak

    2006-12-01

    In the structure of the title complex, [Cu(C3H2O4)(C10H8N3)(H2O)].H2O or [Cu(mal)(dpyam)(H2O)].H2O, where mal is malonate and dpyam is di-2-pyridylamine, the Cu(II) atom displays square-pyramidal geometry, being coordinated by two N atoms from the dpyam ligand, two O atoms from the mal group and one O atom of a water ligand. The complex molecules are linked to form a three-dimensional network by hydrogen-bonding interactions between coordinated/uncoordinated water molecules and the uncoordinated malonate N and O atoms of neighboring molecules.

  20. Electric-dipole-coupled H2O@C60 dimer: Translation-rotation eigenstates from twelve-dimensional quantum calculations

    Science.gov (United States)

    Felker, Peter M.; Bačić, Zlatko

    2017-02-01

    We report on variational solutions to the twelve-dimensional (12D) Schrödinger equation appertaining to the translation-rotation (TR) eigenstates of H2O@C60 dimer, associated with the quantized "rattling" motions of the two encapsulated H2O molecules. Both H2O and C60 moieties are treated as rigid and the cage-cage geometry is taken to be fixed. We consider the TR eigenstates of H2O@C60 monomers in the dimer to be coupled by the electric dipole-dipole interaction between water moieties and develop expressions for computing the matrix elements of that interaction in a dimer basis composed of products of monomer 6D TR eigenstates reported by us recently [P. M. Felker and Z. Bačić, J. Chem. Phys. 144, 201101 (2016)]. We use these expressions to compute TR Hamiltonian matrices of H2O@C60 dimer for two values of the water dipole moment and for various dimer geometries. 12D TR eigenstates of the dimer are then obtained by filter diagonalization. The results reveal two classes of eigenstates, distinguished by the leading order (first or second) at which dipole-dipole coupling contributes to them. The two types of eigenstates differ in the general magnitude of their dipole-induced energy shifts and in the dependence of those shifts on the value of the water dipole moment and on the distance between the H2O@C60 monomers. The dimer results are also found to be markedly insensitive to any change in the orientations of the C60 cages. Finally, the results lend some support for the interpretation that electric dipole-dipole coupling is at least partially responsible for the apparent reduced-symmetry environment experienced by H2O in the powder samples of H2O@C60 [K. S. K. Goh et al., Phys. Chem. Chem. Phys. 16, 21330 (2014)], but only if the water dipole is taken to have a magnitude close to that of free water. The methodology developed in the paper is transferable directly to the calculation of TR eigenstates of larger H2O@C60 assemblies, that will be required for more

  1. H2O2, H2O and HDO thermal mapping on Mars using TEXES/IRTF and EXES/SOFIA

    Science.gov (United States)

    Encrenaz, T.; Greathouse, T.; Richter, M.; Lacy, J.; Fouchet, T.; Bézard, B.; Lefèvre, F.; Montmessin, F.; Atreya, S.

    2014-04-01

    Ever since the Viking era, hydrogen peroxide has been suggested as a possible oxidizer of the Mars surface [1]. H2O2 was first detected in the submillimeter range [2], then regularly monitored, simultaneously with HDO, using high-resolution imaging spectroscopy at 8 μm with TEXES at IRTF [3]. Comparison with the Global Climate Models (GCM) shows that the observations favor the simulations taking into account heterogeneous chemistry [4]. New observations have been performed on H2O2 and HDO with TEXES at IRTF in February 2014, and on H2O and HDO with EXES on SOFIA in April 2014. The latter dataset, obtained near summer solstice, will be used to build a map of D/H on Mars.

  2. In situ Immobilization of Copper Nanoparticles on Polydopamine Coated Graphene Oxide for H2O2 Determination.

    Directory of Open Access Journals (Sweden)

    Yingzhu Liu

    Full Text Available Nanostructured electrochemical sensors often suffer from irreversible aggregation and poor adhesion to the supporting materials, resulting in reduced sensitivity and selectivity over time. We describe a versatile method for fabrication of a H2O2 sensor by immobilizing copper nanoparticles (Cu NPs; 20 nm on graphene oxide (GO sheets via in-situ reduction of copper(II on a polydopamine (PDA coating on a glassy carbon electrode. The PDA film with its amino groups and catechol groups acts as both a reductant and an adhesive that warrants tight bonding between the Cu NPs and the support. The modified electrode, best operated at a working voltage of -0.4 V (vs. Ag/AgCl, has a linear response to H2O2 in the 5 μM to 12 mM concentration range, a sensitivity of 141.54 μA∙mM‾1∙cm‾2, a response time of 4 s, and a 1.4 μM detection limit (at an S/N ratio of 3. The sensor is highly reproducible and selective (with minimal interference to ascorbic acid and uric acid. The method was applied to the determination of H2O2 in sterilant by the standard addition method and gave recoveries between 97% and 99%.

  3. In situ Immobilization of Copper Nanoparticles on Polydopamine Coated Graphene Oxide for H2O2 Determination.

    Science.gov (United States)

    Liu, Yingzhu; Han, Yanwei; Chen, Rongsheng; Zhang, Haijun; Liu, Simin; Liang, Feng

    2016-01-01

    Nanostructured electrochemical sensors often suffer from irreversible aggregation and poor adhesion to the supporting materials, resulting in reduced sensitivity and selectivity over time. We describe a versatile method for fabrication of a H2O2 sensor by immobilizing copper nanoparticles (Cu NPs; 20 nm) on graphene oxide (GO) sheets via in-situ reduction of copper(II) on a polydopamine (PDA) coating on a glassy carbon electrode. The PDA film with its amino groups and catechol groups acts as both a reductant and an adhesive that warrants tight bonding between the Cu NPs and the support. The modified electrode, best operated at a working voltage of -0.4 V (vs. Ag/AgCl), has a linear response to H2O2 in the 5 μM to 12 mM concentration range, a sensitivity of 141.54 μA∙mM‾1∙cm‾2, a response time of 4 s, and a 1.4 μM detection limit (at an S/N ratio of 3). The sensor is highly reproducible and selective (with minimal interference to ascorbic acid and uric acid). The method was applied to the determination of H2O2 in sterilant by the standard addition method and gave recoveries between 97% and 99%.

  4. Relaxation pathways of the OD stretch fundamental of HOD in liquid H2O

    Science.gov (United States)

    Miguel, Beatriz; Zúñiga, José; Requena, Alberto; Bastida, Adolfo

    2016-12-01

    The molecular dynamics with quantum transitions method is used to study the vibrational relaxation of the OD stretching mode of HOD dissolved in liquid H2O water at 303 K. All the vibrational modes of the solute and solvent molecules that participate in the relaxation process are described by quantum mechanics, while the rotational and translational degrees of freedom are treated classically. A modification of the water intramolecular SPC/E (Simple Point Charge/Extended) force field providing vibrational frequencies in solution closer to the experimental values is proposed to analyze the influence of the vibrational energy gaps on the relaxation channels. The relaxation times obtained are in satisfactory agreement with experimental values. The energy transfer during the relaxation process alters significantly the H-bond network around the HOD molecule. The analysis of the vibrational transitions during the relaxation process reveals a complex mechanism which involves the participation of both intra- and intermolecular channels and provides a compromise for the different interpretations of the experimental data reported for this system in recent years.

  5. Synthesis and Crystal Structure of a Nickel(Ⅱ) Complex [Ni(H2btc)2(hmta)2(H2O)] with 1,3,5- Benzenetricarboxylate and Hexamethylenetetramine

    Institute of Scientific and Technical Information of China (English)

    LIN Hong; FENG Yun-Long

    2005-01-01

    The title compound, Ni(H2btc)2(hmta)2(H2O) (C30H35N8NiO13), has been syn- thesized by the reaction of Ni(CH3COO)2(H2O, 1,3,5-benzenetricarboxylate and hexame-thylene- tetramine in DMF and characterized by X-ray single-crystal diffraction.It crystallizes in the orthor- hombic system, space group Pccn with a = 20.610(4), b = 12.246(2), c = 12.907(3) (A), V = 3257(1) (A)3, Z = 4, Mr = 774.37, F(000) = 1612, Dc = 1.579 g/cm3 and μ(MoKα) = 0.677 mm(1.The structure was refined to the final R = 0.0476 and wR = 0.1115 for 3221 observed reflections (I > 2σ(I)).Ni(II) ion is penta-coordinated with two oxygen atoms of monodentate carboxylate groups from two 1,3,5- benzenetricarboxylates, two nitrogen atoms from two hexamethylenetetramines in the equatorial plane, and one water molecule in the axial position.The coordination geometry of Ni(II) can be described as a nearly ideal square-pyramid.Hydrogen bonds exist between the complex molecules, leading to a two-dimensional structure.

  6. A robust one-compartment fuel cell with a polynuclear cyanide complex as a cathode for utilizing H2O2 as a sustainable fuel at ambient conditions.

    Science.gov (United States)

    Yamada, Yusuke; Yoneda, Masaki; Fukuzumi, Shunichi

    2013-08-26

    A robust one-compartment H2O2 fuel cell, which operates without membranes at room temperature, has been constructed by using a series of polynuclear cyanide complexes that contain Fe, Co, Mn, and Cr as cathodes, in sharp contrast to conventional H2 and MeOH fuel cells, which require membranes and high temperatures. A high open-circuit potential of 0.68 V was achieved by using Fe3[{Co(III)(CN)6}2] on a carbon cloth as the cathode and a Ni mesh as the anode of a H2O2 fuel cell by using an aqueous solution of H2O2 (0.30  M, pH 3) with a maximum power density of 0.45 mW cm(-2). The open-circuit potential and maximum power density of the H2O2 fuel cell were further increased to 0.78 V and 1.2 mW cm(-2), respectively, by operation under these conditions at pH 1. No catalytic activity of Co3[{Co(III)(CN)6}2] and Co3[{Fe(III)(CN)6}2] towards H2O2 reduction suggests that the N-bound Fe ions are active species for H2O2 reduction. H2O2 fuel cells that used Fe3[{Mn(III)(CN)6}2] and Fe3[{Cr(III)(CN)6}2] as the cathode exhibited lower performance compared with that using Fe3[{Co(III)(CN)6}2] as a cathode, because ligand isomerization of Fe3[{M(III)(CN)6}2] into (FeM2)[{Fe(II)(CN)6}2] (M = Cr or Mn) occurred to form inactive Fe-C bonds under ambient conditions, whereas no ligand isomerization of Fe3[{Co(III)(CN)6}2] occurred under the same reaction conditions. The importance of stable Fe(2+)-N bonds was further indicated by the high performance of the H2O2 fuel cells with Fe3[{Ir(III)(CN)6}2] and Fe3[{Rh(III)(CN)6}2], which also contained stable Fe(2+)-N bonds. The stable Fe(2+)-N bonds in Fe3[{Co(III)(CN)6}2], which lead to high activity for the electrocatalytic reduction of H2O2, allow Fe3[{Co(III)(CN)6}2] to act as a superior cathode in one-compartment H2O2 fuel cells.

  7. Synthesis, Structure and Characterization of Two-dimensional Network Copper Complex [ Cu3 (nta) 2(azpy) 2(H2O)2]· 6H2O

    Institute of Scientific and Technical Information of China (English)

    LI,Bao-Long(李宝龙); XU,Yan(徐艳); LIU,Qi(刘琦); WANG,Hua-Qin(王化勤); XU,Zheng(徐正)

    2002-01-01

    The copper(Ⅱ) complex [Cu3(nta)2(azpy)2(H2O)2] @6H2O(nta= nitrilotriacetate, azpy= 4,4'-azobispyridine) has been synthesized and characterized. The X-ray analysis reveals that there are two kinds of copper(Ⅱ) coordination environments.Cu(1) has a distorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1)is linked to Cu(2)through nta and bound to Cu(1C) by azpy, and Cu(2) islinked to Cu(2A) through azpy, which extends to two-dimensional network with large rhombus 1.2 nm× 1.7 nm.

  8. Synthesis,Crystal Structures and Thermal Stabilities of [Cu(bpp)2(bpdc)H2O)2]n·2nH2O and [Cu(bpp)2]n·n(tdc)·7.5nH2O

    Institute of Scientific and Technical Information of China (English)

    YU,Jing-Hua; WANG,Zhong-Ming; LUO,Xin-Ze; DU,Hong-Guang

    2008-01-01

    Two novel copper(Ⅱ) coordination polymers [Cu(bpp)2(bpdc)(H2O)2]n·2nH2O (1) and [Cu(bpp)2]n·n(tdc)·7.5nH2O (2) (H2bpdc=biphenyl-4,4'-dicarboxylic acid, bpp= 1,3-di(4-pyridyl)propane and H2tdc=thiophene-2,5-dicartboxylic acid) have been synthesized by the reactions of Cu(NO3)2 and bpp with the HEbpdc or HEtdC, respectively at room temperature. In the complexes 1 and 2, their Cu atoms have a distorted octahedral geometry, and two water molecules coordinate weakly to the Cu atom in the long axial direction. Both complexes have one-dimensional linear polymer structures. In complex 1, both carboxylate groups of the bpdc can coordinate to Cu atom, while both carboxylate groups of the tdc dianion in complex 2 do not coordinate to the Cu atom, which only balance the charge. In the both complexes, the bpp ligand has different conformation: trans-trans in complex 1 and trans-gauche in complex 2. The thermal gravimetric analyses indicate that both complexes are stable under 110 and 160℃, respectively.

  9. Ion desorption from frozen H 2O irradiated by MeV heavy ions

    Science.gov (United States)

    Collado, V. M.; Farenzena, L. S.; Ponciano, C. R.; Silveira, E. F. da; Wien, K.

    2004-10-01

    Nitrogen (0.13-0.85 MeV) and 252Cf fission fragments (˜65 MeV) beams are employed to sputter positive and negative secondary ions from frozen water. Desorption yields are measured for different ice temperatures and projectile energies. Target surface is continuously refreshed by condensed water while the target temperature varies and ice thickness changes. In both projectile energy ranges, the preferentially ejected ions are H +, H2+ and (H 2O) nH +-cluster ions. The yields of the corresponding negative ions H - and (H 2O) nO - or (H 2O) nOH - are 1-2 orders of magnitude lower. The (H 2O) nH + desorption yields decrease exponentially as the cluster size, n, increases. In the low energy range, the desorption of positive ion clusters may occur in a two-step process: first, desorption of preformed H 2O clusters and, then, ionization by H + or H 3O + capture. For 0.81 MeV N + projectile ions, the cluster ion emission contributes with 0.05% to the total H 2O desorbed yield. There are indications that emission of the (H 2O) nH + disappears for an electronic energy loss lower than 20 eV/Å. For the high energy range, desorption of small ion clusters is particularly enhanced, revealing that a fragmentation process also exists.

  10. Optical Absorption and Photo-Thermal Conversion Properties of CuO/H2O Nanofluids.

    Science.gov (United States)

    Wang, Liangang; Wu, Mingyan; Wu, Daxiong; Zhang, Canying; Zhu, Qunzhi; Zhu, Haitao

    2015-04-01

    Stable CuO/H2O nanofluids were synthesized in a wet chemical method. Optical absorption property of CuO/H2O nanofluids was investigated with hemispheric transmission spectrum in the wavelength range from 200 nm to 2500 nm. Photo-thermal conversion property of the CuO/H2O nanofluids was studied with an evaluation system equipped with an AUT-FSL semiconductor/solid state laser. The results indicate that CuO/H2O nanofluids have strong absorption in visible light region where water has little absorption. Under the irradiation of laser beam with a wavelength of 635 nm and a power of 0.015 W, the temperature of CuO/H2O nanofluids with 1.0% mass fraction increased by 5.6 °C within 40 seconds. Furthermore, the temperature elevation of CuO/H2O nanofluids was proved to increase with increasing mass fractions. On the contrast, water showed little temperature elevation under the identical conditions. The present work shows that the CuO/H2O nanofluids have high potential in the application as working fluids for solar utilization purpose.

  11. Salidroside Stimulates Mitochondrial Biogenesis and Protects against H2O2-Induced Endothelial Dysfunction

    Science.gov (United States)

    Xing, Shasha; Yang, Xiaoyan; Li, Wenjing; Bian, Fang; Wu, Dan; Chi, Jiangyang; Xu, Gao; Zhang, Yonghui; Jin, Si

    2014-01-01

    Salidroside (SAL) is an active component of Rhodiola rosea with documented antioxidative properties. The purpose of this study is to explore the mechanism of the protective effect of SAL on hydrogen peroxide- (H2O2-) induced endothelial dysfunction. Pretreatment of the human umbilical vein endothelial cells (HUVECs) with SAL significantly reduced the cytotoxicity brought by H2O2. Functional studies on the rat aortas found that SAL rescued the endothelium-dependent relaxation and reduced superoxide anion (O2∙−) production induced by H2O2. Meanwhile, SAL pretreatment inhibited H2O2-induced nitric oxide (NO) production. The underlying mechanisms involve the inhibition of H2O2-induced activation of endothelial nitric oxide synthase (eNOS), adenosine monophosphate-activated protein kinase (AMPK), and Akt, as well as the redox sensitive transcription factor, NF-kappa B (NF-κB). SAL also increased mitochondrial mass and upregulated the mitochondrial biogenesis factors, peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1α), and mitochondrial transcription factor A (TFAM) in the endothelial cells. H2O2-induced mitochondrial dysfunction, as demonstrated by reduced mitochondrial membrane potential (Δψm) and ATP production, was rescued by SAL pretreatment. Taken together, these findings implicate that SAL could protect endothelium against H2O2-induced injury via promoting mitochondrial biogenesis and function, thus preventing the overactivation of oxidative stress-related downstream signaling pathways. PMID:24868319

  12. Peroxiredoxin-2 and STAT3 form a redox relay for H2O2 signaling.

    Science.gov (United States)

    Sobotta, Mirko C; Liou, Willy; Stöcker, Sarah; Talwar, Deepti; Oehler, Michael; Ruppert, Thomas; Scharf, Annette N D; Dick, Tobias P

    2015-01-01

    Hydrogen peroxide (H(2)O(2)) acts as a signaling messenger by oxidatively modifying distinct cysteinyl thiols in distinct target proteins. However, it remains unclear how redox-regulated proteins, which often have low intrinsic reactivity towards H(2)O(2) (k(app) ∼1-10 M(-1) s(-1)), can be specifically and efficiently oxidized by H(2)O(2). Moreover, cellular thiol peroxidases, which are highly abundant and efficient H(2)O(2) scavengers, should effectively eliminate virtually all of the H(2)O(2) produced in the cell. Here, we show that the thiol peroxidase peroxiredoxin-2 (Prx2), one of the most H(2)O(2)-reactive proteins in the cell (k(app) ∼10(7)-10(8) M(-1) s(-1)), acts as a H(2)O(2) signal receptor and transmitter in transcription factor redox regulation. Prx2 forms a redox relay with the transcription factor STAT3 in which oxidative equivalents flow from Prx2 to STAT3. The redox relay generates disulfide-linked STAT3 oligomers with attenuated transcriptional activity. Cytokine-induced STAT3 signaling is accompanied by Prx2 and STAT3 oxidation and is modulated by Prx2 expression levels.

  13. Theoretical Studies on the Stabilities and Hydrogen Bond Actions of (H2O)n Clusters

    Institute of Scientific and Technical Information of China (English)

    MENG Xiang-Jun; WANG Ke-Cheng; WU Wen-Sheng; LI Bing-Huan; WANG De-Jin

    2006-01-01

    The stable configurations and hydrogen bond nature of (H2O)n clusters (n = 3~6) have been investigated by the B3LYP method at the 6-31++g** level. Upon calculation, four conclusions have been drawn: (1) In the (H2O)3~5 clusters, cyclic configurations were confirmed to be the most stable. But in the (H2O)3~4 ones, only cyclic configurations could be observed. From n= 5 ((H2O)5 clusters), three-dimensional configuration could be found; (2) In the (H2O)6 clusters, all configurations are inclined to be three-dimensional except the most stable configuration which is cyclic; (3) The stable order of (H2O)6 clusters indicates that it is the arrangement of hydrogen bond that plays a decisive role in the cluster stabilities, the zero-point energy is also important, and cluster stabilities are independent on the number of hydrogen bonds; (4) There exist strong cooperativity and superadditivity in the (H2O)n clusters.

  14. H2O2 dynamics in the malaria parasite Plasmodium falciparum

    Science.gov (United States)

    Rahbari, Mahsa; Bogeski, Ivan

    2017-01-01

    Hydrogen peroxide is an important antimicrobial agent but is also crucially involved in redox signaling and pathogen-host cell interactions. As a basis for systematically investigating intracellular H2O2 dynamics and regulation in living malaria parasites, we established the genetically encoded fluorescent H2O2 sensors roGFP2-Orp1 and HyPer-3 in Plasmodium falciparum. Both ratiometric redox probes as well as the pH control SypHer were expressed in the cytosol of blood-stage parasites. Both redox sensors showed reproducible sensitivity towards H2O2 in the lower micromolar range in vitro and in the parasites. Due to the pH sensitivity of HyPer-3, we used parasites expressing roGFP2-Orp1 for evaluation of short-, medium-, and long-term effects of antimalarial drugs on H2O2 levels and detoxification in Plasmodium. None of the quinolines or artemisinins tested had detectable direct effects on the H2O2 homeostasis at pharmacologically relevant concentrations. However, pre-treatment of the cells with antimalarial drugs or heat shock led to a higher tolerance towards exogenous H2O2. The systematic evaluation and comparison of the two genetically encoded cytosolic H2O2 probes in malaria parasites provides a basis for studying parasite-host cell interactions or drug effects with spatio-temporal resolution while preserving cell integrity. PMID:28369083

  15. Salidroside Stimulates Mitochondrial Biogenesis and Protects against H2O2-Induced Endothelial Dysfunction

    Directory of Open Access Journals (Sweden)

    Shasha Xing

    2014-01-01

    Full Text Available Salidroside (SAL is an active component of Rhodiola rosea with documented antioxidative properties. The purpose of this study is to explore the mechanism of the protective effect of SAL on hydrogen peroxide- (H2O2- induced endothelial dysfunction. Pretreatment of the human umbilical vein endothelial cells (HUVECs with SAL significantly reduced the cytotoxicity brought by H2O2. Functional studies on the rat aortas found that SAL rescued the endothelium-dependent relaxation and reduced superoxide anion (O2∙- production induced by H2O2. Meanwhile, SAL pretreatment inhibited H2O2-induced nitric oxide (NO production. The underlying mechanisms involve the inhibition of H2O2-induced activation of endothelial nitric oxide synthase (eNOS, adenosine monophosphate-activated protein kinase (AMPK, and Akt, as well as the redox sensitive transcription factor, NF-kappa B (NF-κB. SAL also increased mitochondrial mass and upregulated the mitochondrial biogenesis factors, peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1α, and mitochondrial transcription factor A (TFAM in the endothelial cells. H2O2-induced mitochondrial dysfunction, as demonstrated by reduced mitochondrial membrane potential (Δψm and ATP production, was rescued by SAL pretreatment. Taken together, these findings implicate that SAL could protect endothelium against H2O2-induced injury via promoting mitochondrial biogenesis and function, thus preventing the overactivation of oxidative stress-related downstream signaling pathways.

  16. Decoloration Kinetics of Waste Cooking Oil by 60Co γ-ray/H2O2

    Science.gov (United States)

    Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng

    2016-03-01

    In order to decolorize, waste cooking oil, a dark red close to black solution from homes and restaurants, was subjected to 60Co γ-ray/H2O2 treatment. By virtue of UV/Vis spectrophotometric method, the influence of Gamma irradiation to decoloration kinetics and rate constants of the waste cooking oil in the presence of H2O2 was researched. In addition, the influence of different factors such as H2O2 concentration and irradiation dose on the decoloration rate of waste cooking oil was investigated. Results indicated that the decoloration kinetics of waste cooking oil conformed to the first-order reaction. The decoloration rate increased with the increase of irradiation dose and H2O2 concentration. Saponification analysis and sensory evaluation showed that the sample by 60Co γ-ray/H2O2 treatment presented better saponification performance and sensory score. Furthermore, according to cost estimate, the cost of the 60Co γ-ray/H2O2 was lower and more feasible than the H2O2 alone for decoloration of waste cooking oil.

  17. Coordination polymer based on Cu(II), Co(II) and 4,4'-bipyridine-2,6,2',6'-tetracarboxylate: synthesis, structure and adsorption properties.

    Science.gov (United States)

    Zhao, Zhou; He, Xiang; Zhao, Yongmei; Shao, Min; Zhu, Shourong

    2009-04-21

    4,4'-Bipyridine-2,6,2',6'-tetracarboxylic acid H4L.3H2O, () and its copper(II) and cobalt (II) coordination polymers [Cu2L(H2O)4]2n () and {[Co(H2O)6].[Co3L2(H2O)2].10H2O}3n () have been hydrothermally synthesized. Compound packs into a crystal via H-bonds. Complex is a 2D coordination grid, in which Cu is in an elongated octahedral constructed by a mer-geometry pyridyl-2,6-dicarboxylate, one bridging carboxylate oxygen and two water molecules. The L4- is central symmetrical. Each pyridyl-2,6-dicarboxylate chelete to Cu(II) and one carboxylate bridge Cu(II) ions in a 1,1-fashion. The 2D coordination polymer links to adjacent layers via H-bonds. Complex is a metal-organic framework with 11.6x10.5 A rectangular channels. All Co(II) ions are located in an octahedral coordination environment. The rectangular channels are composed of Co2+-L4- walls and the walls are linked through carboxylate oxygen atoms and Co(II) ions. Co(H2O)6(2+) as counter ions fill in porous channel. The removal of water molecules from at 210 degrees C or higher affords the porous material [Co4L2]n, which can adsorb 16 (36%) methanol or 9 (32%) ethanol in the vapour phase. The porosity of is higher than reported 4,4'-bipyridine-2,6,2',6'- tetracarboxylate complexes. The framework of remains but the crystallinity is lost upon removal of the H2O molecules. The dehydrated framework of partially recovery crystallinity after it adsorbs H2O, CH3OH and C2H5OH. The methanol in the framework can be replaced by H2O reversibly.

  18. Lateral variation of H2O contents in Quaternary Magma of central Northeastern Japan arc

    Science.gov (United States)

    Miyagi, I.; Matsu'ura, T.; Itoh, J.; Morishita, Y.

    2011-12-01

    Water plays a key role in the genesis and eruptive mechanisms of subduction zone volcanoes. We estimated bulk rock water content of both frontal and back arc volcanoes from Northeastern Japan arc in order to understand the lateral variation of magmatic H2O contents in the island arc magma. Our analytical targets are the Adachi volcano located near the volcanic front and the Hijiori volcano located on back arc side. In this study, the bulk magmatic H2O content is estimated by a simple mass balance calculation of the chemistry of bulk rock and melt inclusions in phenocrysts; the melt H2O contents of melt inclusions analyzed by SIMS or EPMA are corrected according to the difference in K2O content between melt inclusions and bulk rock. The bulk magmatic H2O we obtained is 8 wt. % or even more for Adachi and is 2-3 wt. % for Hijiori. Thus, the frontal volcano has higher H2O than the back arc volcano. Although our data are opposed to the previous estimation on the lateral variation of H2O contents in Quaternary volcanoes of Northeastern Japan arc (e.g., Sakuyama, 1979), thermodynamic computations using MELTS (Ghiorso and Sack, 1995) suggest that the amount of bulk magmatic H2O we estimated is consistent with petrographical observations. Our data imply a regional characteristics in the type of eruption that the H2O rich frontal volcanoes will erupt explosively and those H2O poor back arc ones will be effusive, which implication is consistent with actual geological observations that volcanoes located on back arc side of the Northeastern Japan arc generally comprise lava flow (e.g., Iwaki, Kanpu, Chokai, Gassan), in contrast to the frontal ones that produced voluminous tephra (e.g., Osorezan, Towada, Narugo, Adachi). This research project has been conducted under the research contract with Nuclear and Industrial Safety Agency (NISA).

  19. Factors affecting ultraviolet irradiation/hydrogen peroxide (UV/H2O2) degradation of mixed N-nitrosamines in water.

    Science.gov (United States)

    Zhou, Chao; Gao, Naiyun; Deng, Yang; Chu, Wenhai; Rong, Wenlei; Zhou, Shengdong

    2012-09-15

    Disinfection by-products (DBPs) are a great challenge to our drinking water security. Particularly, nitrosamines (NAms), as emerging DBPs, are potently carcinogenic, mutagenic, and teratogenic, and have increasingly attained public attention. This study was to evaluate the performance of the NAms degradation by the ultraviolet (UV) irradiation (253.7 nm) in the presence of hydrogen peroxide (H(2)O(2)). In the UV/H(2)O(2) system, hydroxyl radicals (OH), a type of nonselective and powerful oxidant, was produced to attack the molecules of NAms. Factors affecting the treatment efficiency, including the H(2)O(2) dosage, initial NAms concentration, UV irradiation intensity, initial solution pH, and inorganic anions present in water, were evaluated. All the NAms degradation exhibited a pseudo-first-order kinetics pattern. Within 60 min, 0.1 mg/L of any NAms could be almost decomposed except NDPhA that required 120 min for complete removal, at 25 μmol/L H(2)O(2) and at initial pH 7. Results demonstrate that the UV/H(2)O(2) treatment is a viable option to control NAms in water.

  20. Sonolytic Oxidation of Tc(IVO2nH2O Nanoparticles to Tc(VIIO4 in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    M. Zakir

    2010-04-01

    Full Text Available Sonolysis of a hydrosol of TcO2nH2O was investigated in the Ar- or He- atmosphere. Colloidal TcO2nH2O nanoparticles were irradiated with a 200 kHz and 1.25 W/cm2 ultrasound. It was found that the TcO2nH2O colloids dispersed in an aqueous solution (under Ar or He atmosphere was completely dissolved by ultrasonic irradiation (200 kHz, 200 W. The original brownish black color of the suspension slowly disappeared leaving behind a colorless solution. This change suggests that oxidation of Tc(IV to Tc(VII takes place. The oxidation was almost complete during 30 minutes sonication time under argon atmosphere for initial concentration of 6.0E-5 M. Addition of t-butyl alcohol, an effective radical scavenger which readily reacts with OH radicals, supressed the dissolution of TcO2nH2O colloids. This reaction indicates that TcO2nH2O molecules are oxidized by OH radicals produced in cavitation bubbles.

  1. 竹浆常规三段漂E段添加H2O2

    Institute of Scientific and Technical Information of China (English)

    唐红梅; 庞业娟

    2003-01-01

    研究常规三段漂E段添加H2O2加强漂白的效果.结果表明,加入H2O2后漂白各段用药量得到大幅度降低,粘度却提高了150~250ml/g;浆料白度高,粘度损失小,强度高;在H2O2用量较低的情况下浆的质量稳定,返黄率低.

  2. High-Velocity H2O Masers Associated Massive Star Formation Regions

    Institute of Scientific and Technical Information of China (English)

    徐烨; 蒋栋荣; 郑兴武; 顾敏峰; 俞志尧; 裴春传

    2001-01-01

    We report on the results of 12 CO (1-0) emission associated with H2O masers and massive star formation regions to identify high-velocity H2O masers. Several masers have a large blueshift, even up to 120 km.s-1, with respect to the CO peak, but no large redshifted maser appears. This result suggests that high-velocity H2O masers can most probably occur in high mass star-forming regions and quite a number of masers stem from the amplifications of a background source, which may enable those undetectable weak masers to come to an observable level.

  3. Geometry and bond-length alternation in nonlinear optical materials. II. Effects of donor strength in two push-pull molecules.

    Science.gov (United States)

    Gainsford, Graeme J; Bhuiyan, M Delower H; Kay, Andrew J

    2008-04-01

    The compounds N-[2-(4-cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydrofuran-3-yl)vinyl]-N-phenylacetamide, C(20)H(16)N(4)O(2), (I), and 2-{3-cyano-5,5-dimethyl-4-[2-(piperidin-1-yl)vinyl]-2,5-dihydrofuran-2-ylidene}malononitrile 0.376-hydrate, C(17)H(18)N(4)O x 0.376 H(2)O, (II), are novel push-pull molecules. The significant bonding changes in the polyene chain compared with the parent molecule 2-dicyanomethylene-4,5,5-trimethyl-2,5-dihyrofuran-3-carbonitrile are consistent with the relative electron-donating properties of the acetanilido and piperidine groups. The packing of (I) utilizes one phenyl-cyano C-H...N and two phenyl-carbonyl C-H...O hydrogen bonds. Compound (II) crystallizes with a partial water molecule (0.376H(2)O), consistent with cell packing that is dominated by attractive C-H...N(cyano) interactions. These compounds are precursors to novel nonlinear optical chromophores, studied to assess the impact of donor strength and the extent of conjugation on bond-length alternation, crystal packing and aggregation.

  4. Infinite Three-Dimensional Coordination Polymers: Synthesis and Structures of [Cd (4,4'-bpy)2 (H2O)2]n (pic)2n, [Zn (4,4'-bpy)2 (H2O)2 ]n-(pic)2n (H2O)2n, and [Zn (4,4'-bpy)2 (H2O)2]n (4,4'-bpy)n (H2O)n (pic)2n

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Three Complexes of the formula [ Cd (4,4'-bpy)2 (H2O)2 ]n (pic)2n (1), [ Zn (4,4'-bpy)2 (H2O)2 ]n-(pic)2n (H2O)2n (2) and [ Zn (4,4'-bpy)2 (H2O)2 ]n (4,4'-bpy)n (pic)2n (H2O)n (3) ( 4,4'-bpy = 4,4'-bipyridine; pic = picric anion ) have been synthesized and characterized by elemental analysis and single-crystal x-ray diffraction. They all have infinite three-dimensional network structure, crystallizing in the monoclinic space group C2/c (1) and Cc (2,3).

  5. The dimers of glyoxal and acrolein with H 2O and HF: Negative intramolecular coupling and blue-shifted C-H stretch

    Science.gov (United States)

    Karpfen, Alfred; Kryachko, Eugene S.

    2010-04-01

    The structures and the vibrational spectra of the hydrogen-bonded complexes: glyoxal-H 2O, glyoxal-HF, acrolein-H 2O, and acrolein-HF, are investigated within the MP2/aug-cc-pVTZ computational approach. It is demonstrated that the calculated blue shifts of the C-H stretching frequencies in the glyoxal-H 2O complexes are only indirectly pertinent to hydrogen bonding to the C-H group. The comparison with the glyoxal-HF and the acrolein-HF complexes reveals that these blue shifts are a direct consequence of a negative intramolecular coupling between vicinal C dbnd O and C-H bonds in the aldehyde groups of isolated glyoxal and acrolein molecules. To support this interpretation, the halogen-bonded complexes glyoxal-BrF and acrolein-BrF are discussed.

  6. Quantum tunneling during interstellar surface-catalyzed formation of water: the reaction H + H$_2$O$_2$ $\\rightarrow$ H$_2$O + OH

    CERN Document Server

    Lamberts, Thanja; Köhn, Andreas; Kästner, Johannes

    2016-01-01

    The final step of the water formation network on interstellar grain surfaces starting from the H + O$_2$ route is the reaction between H and H$_2$O$_2$. This reaction is known to have a high activation energy and therefore at low temperatures it can only proceed via tunneling. To date, however, no rate constants are available at temperatures below 200 K. In this work, we use instanton theory to compute rate constants for the title reaction with and without isotopic substitutions down to temperatures of 50 K. The calculations are based on density functional theory, with additional benchmarks for the activation energy using unrestricted single-reference and multireference coupled-cluster single-point energies. Gas-phase bimolecular rate constants are calculated and compared with available experimental data not only for H + H$_2$O$_2$ $\\rightarrow$ H$_2$O + OH, but also for H + H$_2$O$_2$ $\\rightarrow$ H$_2$ + HO$_2$. We find a branching ratio where the title reaction is favored by at least two orders of magnitu...

  7. Nanoparticle formation in H2O/N-2 and H2O/Ar mixtures under irradiation by 20 MeV protons and positive corona discharge

    DEFF Research Database (Denmark)

    Imanaka, M.; Tomita, S.; Kanda, S.

    2010-01-01

    To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using a diffe...... positive and negative ions for the formation of nanosize droplets, which attract each other by Coulomb interactions, enhancing the collision frequency and leading to the formation of the 10 nm droplets.......To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using...... a differential mobility analyzer equipped with a Faraday cup electrometer. Using the proton beam, droplets around 10 nm in diameter were observed for both positively and negatively charged particles, but none were found when the corona discharge was used. This implies the importance of the presence of both...

  8. A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O

    DEFF Research Database (Denmark)

    Parsons, M.T.; Westh, Peter; Davies, J.V.

    2001-01-01

    The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization...

  9. H2O and CO2 in magmas from the Mariana arc and back arc systems

    Science.gov (United States)

    Newman, Sally; Stolper, Edward; Stern, Robert

    2000-05-01

    We examined the H2O and CO2 contents of glasses from lavas and xenoliths from the Mariana arc system, an intraoceanic convergent margin in the western Pacific, which contains an active volcanic arc, an actively spreading back arc basin, and active behind-the-arc cross-chain volcanoes. Samples include (1) glass rims from Mariana arc, Mariana trough, and cross-chain submarine lavas; (2) glass inclusions in arc and trough phenocrysts; and (3) glass inclusions from a gabbro + anorthosite xenolith from Agrigan (Mariana arc). Glass rims of submarine arc lavas contain 0.3-1.9 wt % H2O, and CO2 is below detection limits. Where they could be compared, glass inclusions in arc phenocrysts contain more H2O than their host glasses; most arc glasses and phenocryst inclusions contain no detectable CO2, with the exception of those from a North Hiyoshi shoshonite, which contains 400-600 ppm. The glass inclusions from the Agrigan xenolith contain 4-6% H2O, and CO2 is below the detection limit. Glasses from the cross-chain lavas are similar to those from the arc: H2O contents are 1.4-1.7 wt %, and CO2 is below detection limits. Volatile contents in Mariana trough lava glass rims are variable: 0.2-2.8 wt % H2O and 0-300 ppm CO2. Glass inclusions from trough phenocrysts have water contents similar to the host glass, but they can contain up to 875 ppm CO2. Volatile contents of melt inclusions from trough and arc lavas and from the xenolith imply minimum depths of crystallization of ~1-8 km. H2O and CO2 contents of Mariana trough glasses are negatively correlated, indicating saturation of the erupting magma with a CO2-H2O vapor at the pressure of eruption (~400 bars for these samples), with the vapor ranging from nearly pure CO2 at the CO2-rich end of the glass array to nearly pure H2O at the H2O-rich end. Degassing of these magmas on ascent and eruption leads to significant loss of CO2 (thereby masking preeruptive CO2 contents) but minimal disturbance of preeruptive H2O contents. For

  10. (μ-Ethane-1,1,2,2-tetracarboxylatobis[tetraaquamanganese(II

    Directory of Open Access Journals (Sweden)

    Meng-Wei Xue

    2011-04-01

    Full Text Available In the centrosymmetric title molecule, [Mn2(C6H2O8(H2O8], the MnII atom is in an octahedral environment coordinated by six O-atom donors from water molecules and ethane-1,1,2,2-tetracarboxylate ligands. The crystal structure features a three-dimensional hydrogen-bonding network based on a strong and distinctive pattern of O—H...O hydrogen-bonding interactions.

  11. Contrasting atmospheric boundary layer chemistry of methylhydroperoxide (CH3OOH and hydrogen peroxide (H2O2 above polar snow

    Directory of Open Access Journals (Sweden)

    D. K. Friel

    2009-05-01

    Full Text Available Atmospheric hydroperoxides (ROOH were measured at Summit, Greenland (72.97° N, 38.77° W in summer 2003 (SUM03 and spring 2004 (SUM04 and South Pole in December 2003 (SP03. The two dominant hydroperoxides were H2O2 and CH3OOH (from here on MHP with average (±1σ mixing ratios of 1448 (±688 pptv, 204 (±162 and 278 (±67 for H2O2 and 578 (±377 pptv, 139 (±101 pptv and 138 (±89 pptv for MHP, respectively. In early spring, MHP dominated the ROOH budget and showed night time maxima and daytime minima, out of phase with the diurnal cycle of H2O2, suggesting that the organic peroxide is controlled by photochemistry, while H2O2 is largely influenced by temperature driven exchange between the atmosphere and snow. Highly constrained photochemical box model runs yielded median ratios between modeled and observed MHP of 52%, 148% and 3% for SUM03, SUM04 and SP03, respectively. At Summit firn air measurements and model calculations suggest a daytime sink of MHP in the upper snow pack, which decreases in strength through the spring season into the summer. Up to 50% of the estimated sink rates of 1–5×1011 molecules m−3 s−1 equivalent to 24–96 pptv h−1 can be explained by photolysis and reaction with the OH radical in firn air and in the quasi-liquid layer on snow grains. Rapid processing of MHP in surface snow is expected to contribute significantly to a photochemical snow pack source of formaldehyde (CH2O. Conversely, summer levels of MHP at South Pole are inconsistent with the prevailing high NO concentrations, and cannot be explained currently by known photochemical precursors or transport, thus suggesting a missing source. Simultaneous measurements of H2O2, MHP and CH2O allow to constrain the NO background today and potentially also in the past using ice cores, although it seems less likely that MHP is preserved in firn and ice.

  12. Contrasting atmospheric boundary layer chemistry of methylhydroperoxide (CH3OOH and hydrogen peroxide (H2O2 above polar snow

    Directory of Open Access Journals (Sweden)

    D. K. Friel

    2009-01-01

    Full Text Available Atmospheric hydroperoxides (ROOH were measured at Summit, Greenland (72.97° N, 38.77° W in summer 2003 (SUM03 and spring 2004 (SUM04 and South Pole in December 2003 (SP03. The two dominant hydroperoxides were H2O2 and CH3OOH (from here on MHP with average(±1σ mixing ratios of 1448(±688 pptv, 204(±162 and 278(±67 for H2O2 and 578(±377 pptv, 139(±101 pptv and 138(±89 pptv for MHP, respectively. In early spring, MHP dominated the ROOH budget and showed night time maxima and daytime minima, out of phase with the diurnal cycle of H2O2, suggesting that the organic peroxide is controlled by photochemistry, while H2O2 is largely influenced by temperature driven exchange between the atmosphere and snow. Highly constrained photochemical box model runs yielded median ratios between modeled and observed MHP of 52%, 148% and 3% for SUM03, SUM04 and SP03, respectively. At Summit firn air measurements and model calculations suggest a daytime sink of MHP in the upper snow pack, which decreases in strength through the spring season into the summer. Up to 50% of the estimated sink rates of 1–5×1011 molecules m−3 s−1 equivalent to 24–96 pptv h−1 can be explained by photolysis and reaction with the OH radical in firn air and in the quasi-liquid layer on snow grains. Rapid processing of MHP in surface snow is expected to contribute significantly to a photochemical snow pack source of formaldehyde (CH2O. Conversely, summer levels of MHP at South Pole are inconsistent with the prevailing high NO concentrations, and cannot be explained currently by known photochemical precursors or transport, thus suggesting a missing source. Simultaneous measurements of H2O2, MHP and CH2O allow to constrain the NO background today and potentially also in the past using ice cores, although it seems less likely that MHP is preserved in firn and ice.

  13. Hexaaquazinc(II) dichloride bis(hexamethylenetetramine) tetrahydrate

    OpenAIRE

    Wen Wu; Ya Wen Xuan; Xin Jian Yao

    2008-01-01

    The title compound, [Zn(H2O)6]Cl2·2C6H12N4·4H2O, has been prepared under mild hydrothermal conditions. The ZnII atom, located on a centre of symmetry, is coordinated by six water molecules in a distorted octahedral coordination geometry. The hexamethylenetetramine molecule is not coordinated to ZnII but links the Zn complexes via three O—H...N hydrogen bonds. The remaining N atom of the hexamethylenetetramine molecule is hydrogen-bonded to a solvent water molecule. In the crys...

  14. In situ cryogenic Raman spectroscopic studies on the synthetic fluid inclusions in the systems H2O and NaCl-H2O

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Salt-hydrates have diagnostic cryogenic Raman spectra, which can reflect the composition of the parent solutions. As analogue to the natural fluid inclusions, the synthetic inclusions can be used to validate numerous assumptions related to fluid inclusion research. They can also be used to test the feasibility of application of laser Raman spectroscopy to individual fluid inclusion analysis. Using the technique proposed by Sterner and Bodnar(1984), synthetic inclusions of the systems H2O and NaCl-H2O (with NaCl as 5.12 wt%, 9.06 wt%, 16.6 wt% and 25 wt%) were formed under the pressures from 50Mpa to 100Mpa and at the temperatures from 500℃ to 600℃. In situ cryogenic Raman spectra were collected at about -180℃ by combined use of freezing- heating stage and Laser Raman Microscopy. It is shown that hydrohalite (NaCl·2H2O), the salt-hydrate of NaCl in the fluid inclusions has the specific Raman spectrum and can be used as the standard to verify the existence of NaCl in the aqueous inclusions. The crystalline ice other than amorphous ice (glasses) formed from the aqueous phase whthin the synthetic inclusions during the initial freezing, but hydrohalite did not form. Subsequent warming of these inclusions induced a phase change, typically between approximately -40 and -22℃, that represents the hydrohalite crystallization event but not a eutectic melting event. So, for fluid inclusions in the system NaCl-H2O, interpretation of phase behavior below the eutectic temperature (-20.8℃) should be made with caution. The ratios of the relative intensity and the area of Raman spectra between 3423 cm-1 peak of hydrohalite and 3098 cm-1 peak of ice show positive correlations to the salinities in aqueous inclusions, which can be used to determine the salinity of NaCl- H2O system inclusions.

  15. The HO2 + (H2O)n + O3 reaction: an overview and recent developments*

    Science.gov (United States)

    Viegas, Luís P.; Varandas, António J. C.

    2016-03-01

    The present work is concerned with the reaction of the hydroperoxyl radical with ozone, which is key in the atmosphere. We first give a brief overview which emphasizes theoretical work developed at the authors' Group, considering not only the naked reaction (n = 0) but also the reaction with one water molecule added to the reactants (n = 1). Aiming at a broad and contextual understanding of the role of water, we have also very recently published the results of the investigation considering the addition of water dimers (n = 2) and trimers (n = 3) to the reactants. Such results are also succinctly addressed before we present our latest and unpublished research endeavors. These consist of two items: the first one addresses a new mechanistic pathway for hydrogen-abstraction in n = 2-4 cases, in which we observe a Grotthuss-like hydrogen shuttling mechanism that interconverts covalent and hydrogen bonds (water molecules are no longer spectators); the second addresses our exploratory calculations of the HO2 + O3 reaction inside a (H2O)20 water cage, where we strive to give a detailed insight of the molecular processes behind the uptake of gas-phase molecules by a water droplet. Supplementary material in the form of one zip file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-60733-5Contribution to the Topical Issue "Atomic Cluster Collisions (7th International Symposium)", edited by Gerardo Delgado Barrio, Andrey Solov'Yov, Pablo Villarreal, Rita Prosmiti.

  16. Degradation Mechanisms of Dimethyl Phthalate in the UV-H2O2 System%邻苯二甲酸二甲酯的紫外光-H2O2降解机制研究

    Institute of Scientific and Technical Information of China (English)

    刘青; 陈成; 陈泓哲; 杨绍贵; 何欢; 孙成

    2013-01-01

    为研究邻苯二甲酸二甲酯(DMP)在紫外光(UV)-H2O2体系下的光降解机制,利用质谱仪鉴定了目标化合物的降解产物,并借此推测其可能的降解途径.结果表明,在UV-H2O2的体系中,10 mg·L-1的DMP在90 min内的降解率达到92.3%,溶液pH值由初始的6.50降至4.98.通过GC/MS、LC/MS分析,DMP在UV-H2O2降解过程中的产物有六类,并且推断出DMP的两条侧链同时发生水解作用,生成的邻苯二甲酸可以异构为更加稳定的对苯二甲酸.此外,DMP还可以发生苯环取代、侧链缩合成环等反应,最后,在·OH的作用下,DMP及其芳香族中间产物发生开环反应,苯环被破坏,生成多种小分子有机酸,并进一步矿化为CO2和水.%To investigate the photodegradation process of dimethyl phthalate (DMP) in the ultraviolet light (UV)-H2O2 system,mass spectrometer was used to identify degradation products and further more,to speculate the possible mechanisms of degradation process.Experimental results showed that the degradation efficiency of 10 mg· L-1 DMP reached 92.3 % in 90minutes in the UV-H2O2 system,and the more H2O2 was added,the faster DMP decomposed.The pH of DMP solution decreased from the initial 6.5 to 4.98,because of the generating of organic phenolic acids and small acid molecules generated by the degradation of DMP.By the GC/MS as well as LC/MS analysis,degradation products of the DMP in the UV-H2O2 system were thought to comprise six categories,from which we could infer that hydrolysis occurs simultaneously on the two side chains of the DMP,generating phthalic acid that can quickly change to the more stable terephthalic acid.In addition,DMP could also occur benzene ring replacement as well as the ring condensed of the side chains.Finally,by the role of · OH,DMP and its aromatic intermediates occurred ring-opening reaction,and benzene ring was destroyed and generated organic acids of small molecular,which was further mineralized to CO2 and water.

  17. Redetermination of kovdorskite, Mg(2)PO(4)(OH)·3H(2)O.

    Science.gov (United States)

    Morrison, Shaunna M; Downs, Robert T; Yang, Hexiong

    2012-02-01

    The crystal structure of kovdorskite, ideally Mg(2)PO(4)(OH)·3H(2)O (dimagnesium phosphate hydroxide trihydrate), was reported previously with isotropic displacement paramaters only and without H-atom positions [Ovchinnikov et al. (1980 ▶). Dokl. Akad. Nauk SSSR.255, 351-354]. In this study, the kovdorskite structure is redetermined based on single-crystal X-ray diffraction data from a sample from the type locality, the Kovdor massif, Kola Peninsula, Russia, with anisotropic displacement parameters for all non-H atoms, with all H-atom located and with higher precision. Moreover, inconsistencies of the previously published structural data with respect to reported and calculated X-ray powder patterns are also discussed. The structure of kovdorskite contains a set of four edge-sharing MgO(6) octa-hedra inter-connected by PO(4) tetra-hedra and O-H⋯O hydrogen bonds, forming columns and channels parallel to [001]. The hydrogen-bonding system in kovdorskite is formed through the water mol-ecules, with the OH(-) ions contributing little, if any, to the system, as indicated by the long H⋯A distances (>2.50 Å) to the nearest O atoms. The hydrogen-bond lengths determined from the structure refinement agree well with Raman spectroscopic data.

  18. Redetermination of kovdorskite, Mg2PO4(OH·3H2O

    Directory of Open Access Journals (Sweden)

    Shaunna M. Morrison

    2012-02-01

    Full Text Available The crystal structure of kovdorskite, ideally Mg2PO4(OH·3H2O (dimagnesium phosphate hydroxide trihydrate, was reported previously with isotropic displacement paramaters only and without H-atom positions [Ovchinnikov et al. (1980. Dokl. Akad. Nauk SSSR. 255, 351–354]. In this study, the kovdorskite structure is redetermined based on single-crystal X-ray diffraction data from a sample from the type locality, the Kovdor massif, Kola Peninsula, Russia, with anisotropic displacement parameters for all non-H atoms, with all H-atom located and with higher precision. Moreover, inconsistencies of the previously published structural data with respect to reported and calculated X-ray powder patterns are also discussed. The structure of kovdorskite contains a set of four edge-sharing MgO6 octahedra interconnected by PO4 tetrahedra and O—H...O hydrogen bonds, forming columns and channels parallel to [001]. The hydrogen-bonding system in kovdorskite is formed through the water molecules, with the OH− ions contributing little, if any, to the system, as indicated by the long H...A distances (>2.50 Å to the nearest O atoms. The hydrogen-bond lengths determined from the structure refinement agree well with Raman spectroscopic data.

  19. Preparation of a Superhydrophobic and Peroxidase-like Activity Array Chip for H2O2 Sensing by Surface-Enhanced Raman Scattering.

    Science.gov (United States)

    Yu, Zhi; Park, Yeonju; Chen, Lei; Zhao, Bing; Jung, Young Mee; Cong, Qian

    2015-10-28

    In this paper, we propose a novel and simple method for preparing a dual-biomimetic functional array possessing both superhydrophobic and peroxidase-like activity that can be used for hydrogen peroxide (H2O2) sensing. The proposed method is an integration innovation that combines the above two properties and surface-enhanced Raman scattering (SERS). We integrated a series of well-ordered arrays of Au points (d = 1 mm) onto a superhydrophobic copper (Cu)/silver (Ag) surface by replicating an arrayed molybdenum template. Instead of using photoresists and the traditional lithography method, we utilized a chemical etching method (a substitution reaction between Cu and HAuCl4) with a Cu/Ag superhydrophobic surface as the barrier layer, which has the benefit of water repellency. The as-prepared Au points were observed to possess peroxidase-like activity, allowing for catalytic oxidation of the chromogenic molecule o-phenylenediamine dihydrochloride (OPD). Oxidation was evidenced by a color change in the presence of H2O2, which allows the array chip to act as an H2O2 sensor. In this study, the water repellency of the superhydrophobic surface was used to fabricate the array chip and increase the local reactant concentration during the catalytic reaction. As a result, the catalytic reaction occurred when only 2 μL of an aqueous sample (OPD/H2O2) was placed onto the Au point, and the enzymatic product, 2,3-diaminophenazine, showed a SERS signal distinguishable from that of OPD after mixing with 2 μL of colloidal Au. Using the dual-biomimetic functional array chip, quantitative analysis of H2O2 was performed by observing the change in the SERS spectra, which showed a concentration-dependent behavior for H2O2. This method allows for the detection of H2O2 at concentrations as low as 3 pmol per 2 μL of sample, which is a considerable advantage in H2O2 analysis. The as-prepared substrate was convenient for H2O2 detection because only a small amount of sample was required in

  20. Low-temperature heat capacities and thermodynamic properties of rare-earth triisothiocyanate hydrates (Ⅲ)——Sm(NCS)3·6H2O,Gd(NCS)3·6H2O,Yb(NCS)3·6H2O and Y(NCS)3·6H2O

    Institute of Scientific and Technical Information of China (English)

    谭志诚; Matsuo Takasuke; Suga Hiroshi; 张志英; 尹敬执; 蒋本杲; 孙同山

    1997-01-01

    The heat capacities of four RE isothiocyanate hydrates,Sm( NCS)3 6H2O,Gd( NCS)3 6H2O,Yb(NCS)3 6H2O and Y( NCS)3 6H2O,have been measured from 13 to 300 K with a fully-automated adiabatic calorimeter No obvious thermal anomaly was observed for the above-mentioned compounds in the experimental tem-peiatnre ranges.The polynomial equations for calculating the heat capacities of the four compounds in the range of 13-300K were obtained by the least-squares fitting based on the experimental Cp data.The Cp values below 13 K were estimated by using the Debye-Einstem heat capacity functions.The standard molar thermodynamic functions were calculated from 0 to 300 K.Gibbs energies of formation were also calculated.

  1. Influence of H2O Rich Fluid Inclusions on Quartz Deformation

    Science.gov (United States)

    Thust, Anja; Heilbronner, Renée.; Stünitz, Holger; Tarantola, Alexandre; Behrens, Harald

    2010-05-01

    The effect of H2O on the strength of quartz is well known and has been discussed many times in the literature (e.g. Griggs & Blacic 1965, Kronenberg 1994). In this project we study the H2O interactions between natural dry quartz and H2O rich fluid inclusions during deformation in the solid medium Griggs apparatus. High pressure and temperature experiments were carried out using a quartz single crystal containing a large number of H2O-rich fluid inclusions. Adjacent to the fluid inclusions the crystal is essentially dry (Kronenberg A.K., (1994): Hydrogen specifications and chemical weakening of quartz, Rev. Mineral. Ser. 29 (1994), pp. 123-176.

  2. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells

    Data.gov (United States)

    U.S. Environmental Protection Agency — H2O2_COD_EPA: Measurements of hydrogen peroxide and COD concentrations for water samples from the MEC reactors. MEC_acclimation: raw data for current and voltage of...

  3. 40 CFR 1065.370 - CLD CO2 and H2O quench verification.

    Science.gov (United States)

    2010-07-01

    ... analyzer uses quench compensation algorithms that utilize H2O and/or CO2 measurement instruments, evaluate quench with these instruments active and evaluate quench with the compensation algorithms applied....

  4. Photodegradation of Reactive Dyes by UV/Ferrioxalate/H2O2 System

    Institute of Scientific and Technical Information of China (English)

    Wang Binsong(王滨松); Huang Junli; Zhang Jie

    2004-01-01

    Three types of simulated commercial reactive dye wastewater, separately prepared with FN-2BL red, C-R blue and C-2R yellow, were oxidized with UV/ferrioxalate/H2O2 system, especially by the introduction of Fe2+ ion. The experimental results show that the optimized experimental conditions are pH=3.5, [Fe2+]=1mM, H2O2782mg/L for FN-2BL red and C-R blue and H2O2646mg/L for C-2R yellow, t=4h and T=80℃ when the concentration of dye is 400mg/L. Under such conditions, the observed COD and color removal efficiencies are above 94% and 99%, respectively for all the cases. This investigation has provided fundamental information for the treatment of wastewater containing reactive dyes using UV/ferrioxalate/H2O2.

  5. Degradation of Microcystin-RR by Combination of UV/H2O2 Technique

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR (MC-RR) could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.

  6. H2O: An Autonomic, Resource-Aware Distributed Database System

    CERN Document Server

    Macdonald, Angus; Kirby, Graham

    2010-01-01

    This paper presents the design of an autonomic, resource-aware distributed database which enables data to be backed up and shared without complex manual administration. The database, H2O, is designed to make use of unused resources on workstation machines. Creating and maintaining highly-available, replicated database systems can be difficult for untrained users, and costly for IT departments. H2O reduces the need for manual administration by autonomically replicating data and load-balancing across machines in an enterprise. Provisioning hardware to run a database system can be unnecessarily costly as most organizations already possess large quantities of idle resources in workstation machines. H2O is designed to utilize this unused capacity by using resource availability information to place data and plan queries over workstation machines that are already being used for other tasks. This paper discusses the requirements for such a system and presents the design and implementation of H2O.

  7. Confinement effects on the nuclear spin isomer conversion of H$_2$O

    CERN Document Server

    Turgeon, Pierre-Alexandre; Alexandrowicz, Gil; Peperstraete, Yoann; Philippe, Laurent; Fillion, Jean-Hugues; Michaut, Xavier; Ayotte, Patrick

    2016-01-01

    The mechanism for interconversion between the nuclear spin isomers (NSI) of H$_2$O remains shrouded in uncertainties. The temperature dependence displayed by NSI interconversion rates for H$_2$O isolated in an Argon matrix provides evidence that confinement effects are responsible for the dramatic increase in their kinetics with respect to the gas phase, providing new pathways for o-H$_2$O $\\leftrightarrow$ p-H$_2$O conversion in endohedral compounds. This reveals intramolecular aspects of the interconversion mechanism which may improve methodologies for the separation and storage of NSI en route to applications in nuclear magnetic resonance spectroscopy and imaging. It may also improve astronomers' ability to use their relative abundance in the interstellar medium as proxies, thereby providing a valuable "astronomical clock".

  8. Prevention of H2O2 Induced Oxidative Damages of Rat Testis by Thymus algeriensis

    Institute of Scientific and Technical Information of China (English)

    Fatma Guesmi; Hamida Beghalem; Amit K Tyagi; Manel Ben Ali; Ramla Ben Mouhoub; Houda Bellamine; Ahmed Landoulsi

    2016-01-01

    ObjectiveWe evaluate the effects ofThymus algeriensis (TEO) against hydrogen peroxide (H2O2) toxicity on body and testis weight, testis sperm count, testis lipid peroxidation, and antioxidant enzyme activities in rats. MethodsRats were treated with low (LD) and high dose (HD) of H2O2 (0.1 and 1 mmol/L) in the presence or absence of TEO (150 mg/kg). ResultsThe results exhibited a significant decrease in body weight and testis weight, in total sperm number decrease (P ConclusionH2O2 has the ability to alter the sperm function, characteristics and development of testis. However, TEO is an efficient natural agent, which can prevent the testis from H2O2-induced oxidative damage in rats.

  9. Formation of Two-dimensional Metal-water Framework Containing (H2O)2O Cluster

    Institute of Scientific and Technical Information of China (English)

    SUN,Ya-Guang; DING,Fu; GU,Xiao-Fu; ZHANG,Wan-Zhong; WEI,De-Zhou; GAO,En-Jun

    2008-01-01

    [Cd(phen)2(male)(H2O)]·9.5H2O (1) has been synthesized by the reaction of Cd(NO3)2 with phen and male (phen= 1,10-phenanthroline, H2male=maleic acid) in a mixture solvent of ethanol and distilled water. The complex was characterized by elemental analysis, infrared spectrum and thermal gravimetric analyses. The crystal structure was determined by X-ray single-crystal diffraction. In 1, a novel 1D water chain containing water (H2O)20 cluster was formed. Further hydrogen bonding interaction between the water chain and [Cd(phen)2(male)(H2O)] constructs a unique metal-water 2D framework.

  10. An empirical solvus for CO 2-H 2O-2.6 wt% salt

    Science.gov (United States)

    Hendel, Eva Marie; Hollister, Lincoln S.

    1981-02-01

    The solvus in the system CO 2-H 2O-2.6 wt% NaCl-equivalent was determined by measuring temperature of homogenization in fluid inclusions which contained variable CO 2/H 2O but the same amount of salt dissolved in the aqueous phase at room temperature. The critical point of the solvus is at 340 ± 5° C, at pressures between 1 and 2 kbar; this is about 65°C higher than for the pure CO 2-H 2O system. The solvus is assymetrical, with a steeper H 2O-rich limb and with the critical point at mole fraction of water between 0.65 and 0.8.

  11. An Infrared Photometric Study of Galaxies with Extragalactic H2O Maser Sources

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    All galaxies with extragalactic H2O maser sources observed so far are collected. With the 2MASS and the IRAS photometric data an infrared study is performed on those galaxies. By a comparison between the H2O maser detected sources and non-detected sources in the infrared it is indicated that infrared properties in the IRAS 12-25/μm and 60-100/μm are important for producing H2O masers in galaxies. It is also found that the H2O maser galaxies with different nuclear activity types have rather different infrared properties mainly in the IRAS 12-60/μm region.

  12. HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCH2O) contains the entire mission (~3 years) of HIRDLS data...

  13. The 1600 Å Emission Bump in Protoplanetary Disks: A Spectral Signature of H2O Dissociation

    Science.gov (United States)

    France, Kevin; Roueff, Evelyne; Abgrall, Hervé

    2017-08-01

    2 au. We demonstrate that non-thermally populated H2O fragments can qualitatively account for the observed emission (discrete and continuum) and find that the average Lyα-driven H2O dissociation rate is 1.7 × 1042 water molecules s-1. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

  14. Electronic structure and catalytic aspects of [Ru(tpm)(bqdi)(Cl/H2O)]n, tpm = tris(1-pyrazolyl)methane and bqdi = o-benzoquinonediimine.

    Science.gov (United States)

    Agarwala, Hemlata; Ehret, Fabian; Chowdhury, Abhishek Dutta; Maji, Somnath; Mobin, Shaikh M; Kaim, Wolfgang; Lahiri, Goutam Kumar

    2013-03-14

    The diamagnetic complexes [Ru(tpm)(bqdi)(Cl)]ClO(4) ([1]ClO(4)) (tpm = tris(1-pyrazolyl)methane, bqdi = o-benzoquinonediimine) and [Ru(tpm)(bqdi)(H(2)O)](ClO(4))(2) ([2](ClO(4))(2)) have been synthesized. The valence state-sensitive bond distances of coordinated bqdi [C-N: 1.311(5)/1.322(5) Å in [1]ClO(4); 1.316(7)/1.314(7) Å in molecule A and 1.315(6)/1.299(7) Å in molecule B of [2](ClO(4))(2)] imply its fully oxidised quinonediimine (bqdi(0)) character. DFT calculations of 1(+) confirm the {Ru(II)-bqdi(0)} versus the antiferromagnetically coupled {Ru(III)-bqdi˙(-)} alternative. The (1)H NMR spectra of [1]ClO(4) in different solvents show variations in chemical shift positions of the NH (bqdi) and CH (tpm) proton resonances due to their different degrees of acidity in different solvents. In CH(3)CN/0.1 mol dm(-3) Et(4)NClO(4), [1]ClO(4) undergoes one reversible Ru(II)⇌ Ru(III) oxidation and two reductions, the reversible first electron uptake being bqdi based (bqdi(0)/bqdi˙(-)). The electrogenerated paramagnetic species {Ru(III)-bqdi(0)}(1(2+)) and {Ru(II)-Q˙(-)}(1) exhibit Ru(III)-type (1(2+): = 2.211/Δg = 0.580) and radical-type (1: g = 1.988) EPR signals, respectively, as is confirmed by calculated spin densities (Ru: 0.767 in 1(2+), bqdi: 0.857 in 1). The aqua complex [2](ClO(4))(2) exhibits two one-electron oxidations at pH = 7, suggesting the formation of {Ru(IV)[double bond, length as m-dash]O} species. The electronic spectral features of 1(n) (n = charge associated with the different redox states of the chloro complex: 2+, 1+, 0) in CH(3)CN and of 2(2+) in H(2)O have been interpreted based on the TD-DFT calculations. The application potential of the aqua complex 2(2+) as a pre-catalyst towards the epoxidation of olefins has been explored in the presence of the sacrificial oxidant PhI(OAc)(2) in CH(2)Cl(2) at 298 K, showing the desired selectivity with a wide variety of alkenes. DFT calculations based on styrene as the model substrate predict that

  15. Progesterone increases skeletal muscle mitochondrial H2O2 emission in nonmenopausal women.

    Science.gov (United States)

    Kane, Daniel A; Lin, Chien-Te; Anderson, Ethan J; Kwak, Hyo-Bum; Cox, Julie H; Brophy, Patricia M; Hickner, Robert C; Neufer, P Darrell; Cortright, Ronald N

    2011-03-01

    The luteal phase of the female menstrual cycle is associated with both 1) elevated serum progesterone (P4) and estradiol (E2), and 2) reduced insulin sensitivity. Recently, we demonstrated a link between skeletal muscle mitochondrial H(2)O(2) emission (mE(H2O2)) and insulin resistance. To determine whether serum levels of P4 and/or E(2) are related to mitochondrial function, mE(H2O2) and respiratory O(2) flux (Jo(2)) were measured in permeabilized myofibers from insulin-sensitive (IS, n = 24) and -resistant (IR, n = 8) nonmenopausal women (IR = HOMA-IR > 3.6). Succinate-supported mE(H2O2) was more than 50% greater in the IR vs. IS women (P < 0.05). Interestingly, serum P4 correlated positively with succinate-supported mE(H2O2) (r = 0. 53, P < 0.01). To determine whether P4 or E2 directly affect mitochondrial function, saponin-permeabilized vastus lateralis myofibers biopsied from five nonmenopausal women in the early follicular phase were incubated in P4 (60 nM), E2 (1.4 nM), or both. P4 alone inhibited state 3 Jo(2), supported by multisubstrate combination (P < 0.01). However, E2 alone or in combination with P4 had no effect on Jo(2). In contrast, during state 4 respiration, supported by succinate and glycerophosphate, mE(H2O2) was increased with P4 alone or in combination with E2 (P < 0.01). The results suggest that 1) P4 increases mE(H2O2) with or without E2; 2) P4 alone inhibits Jo(2) but not when E2 is present; and 3) P4 is related to the mE(H2O2) previously linked to skeletal muscle insulin resistance.

  16. Recent advances in the chemistry of SmI(2)-H(2)O.

    Science.gov (United States)

    Sautier, Brice; Procter, David J

    2012-01-01

    Recent work from our laboratories has shown SmI(2)-H(2)O to be a versatile, readily-accessible and non-toxic reductant that is more powerful than SmI(2). This review describes the reduction of functional groups that were previously thought to lie beyond the reach of SmI(2) and complexity-generating cyclisations and cyclisation cascades triggered by the reduction of the ester carbonyl group with SmI(2)-H(2)O.

  17. Detection of hydrogen peroxide (H2O2) in the Martian atmosphere with MEX / PFS

    Science.gov (United States)

    Aoki, S.; Kasaba, Y.; Giuranna, M.; Geminale, A.; Sindoni, G.; Nakagawa, H.; Kasai, Y.; Murata, I.; Grassi, D.; Formisano, V.

    2011-10-01

    We first derived the long-term averaged abundance of hydrogen peroxide (H2O2) in the Martian atmosphere with data sets of Planetary Fourier Spectroscopy (PFS) onboard Mars Express (MEX). The total averaged amounts of H2O2 at three Martian years were 45 ± 21 ppb and 25 ± 18 ppb in the forward/reverse pendulum direction, respectively. It could not explain the observed short lifetime of CH4 in the Martian atmosphere.

  18. Ferric and cupric ions requirement for DNA single-strand breakage by H2O2.

    Science.gov (United States)

    Tachon, P

    1989-01-01

    Hydrogen peroxide (H2O2), was able to nick the replicative form of the phage fd, without the addition of a reducing agent or of a metal. This DNA single-strand breakage decreased with an increase of the ionic strength, suggesting that H2O2 reacted with traces of metal bound to DNA. When cupric of ferric ions were added, the rate of DNA single-strand breakage by H2O2 greatly increased and it was 20-30 times faster with cupric than with ferric ions. The addition of EDTA at an equimolar ratio or in excess of metal prevented partially DNA single-strand cleavage by H2O2 in the presence of ferric ions and completely when cupric ions were used. Superoxide dismutase prevented DNA single-strand breakage by H2O2 and ferric ions. On the contrary, with cupric ions and H2O2, the addition of superoxide dismutase increased the rate of DNA single-strand breakage. That superoxide dismutase was acting catalytically was shown by the loss of its effects after heat inactivation of the enzyme. The results of the present study show that besides its involvement in the Fenton reaction, H2O2 is able to reduce the metal bound to DNA, generating the superoxide anion radical or/and its protonated form, the perhydroxyl radical involved in DNA nicking. On the other hand, the ability of cuprous ions unlike ferrous ions to dismutate the superoxide radical may explain some differences observed between iron and copper in the DNA single-strand breakage by H2O2.

  19. Main species and chemical pathways in cold atmospheric-pressure Ar + H2O plasmas

    Science.gov (United States)

    Liu, Dingxin; Sun, Bowen; Iza, Felipe; Xu, Dehui; Wang, Xiaohua; Rong, Mingzhe; Kong, Michael G.

    2017-04-01

    Cold atmospheric-pressure plasmas in Ar + H2O gas mixtures are a promising alternative to He + H2O plasmas as both can produce reactive oxygen species of relevance for many applications and argon is cheaper than helium. Although He + H2O plasmas have been the subject of multiple experimental and computational studies, Ar + H2O plasmas have received less attention. In this work we investigate the composition and chemical pathways in Ar + H2O plasmas by means of a global model that incorporates 57 species and 1228 chemical reactions. Water vapor concentrations from 1 ppm to saturation (32 000 ppm) are considered in the study and abrupt transitions in power dissipation channels, species densities and chemical pathways are found when the water concentration increases from 100 to 1000 ppm. In this region the plasma transitions from an electropositive discharge in which most power is coupled to electrons into an electronegative one in which most power is coupled to ions. While increasing electronegativity is also observed in He + H2O plasmas, in Ar + H2O plasmas the transition is more abrupt because Penning processes do not contribute to gas ionization and the changes in the electron energy distribution function and mean electron energy caused by the increasing water concentration result in electron-neutral excitation and ionization rates changing by many orders of magnitude in a relatively small range of water concentrations. Insights into the main chemical species and pathways governing the production and loss of electrons, O, OH, OH(A) and H2O2 are provided as part of the study.

  20. A DFT/B3LYP study of the mechanisms of the O2 formation reaction catalyzed by the [(terpy)(H2O)Mn(III)(O)2Mn(IV)(OH2)(terpy)](NO3)3 complex: A paradigm for photosystem II.

    Science.gov (United States)

    Sproviero, Eduardo M

    2017-02-20

    We present a theoretical study of the reaction path