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Sample records for anhydrous pyridine etude

  1. Study of the selectivity of poly-nitrogenous extracting molecules in the complexation of actinides (III) and lanthanides (III) in solution in anhydrous pyridine; Etude de la selectivite de molecules extractantes polyazotees dans la complexation des actinides (III) et des lanthanides (III) en solution dans la pyridine anhydre

    Energy Technology Data Exchange (ETDEWEB)

    Riviere, Ch

    2000-10-05

    The aim of this work is to better understand the factors which contribute to the separation of lanthanides(III) and actinides(III). Polydentate nitrogenous molecules present an interesting selectivity. A thermodynamic study of the complexation in pyridine of lanthanide and uranium by the bipyridine ligand (bipy) has been carried out. The formation constants and the thermodynamic values of the different complexes have been determined. It has been shown that the bipy complexes formation is controlled by the enthalpy and unfavored by the entropy. The conductometry has revealed too a significant difference in the uranium and lanthanides complexation by the bipyridine ligand. The use of the phenanthroline ligand induces a better complexation of the metallic ions but the selectivity is not improved. On the other hand, the decrease of the basicity and the increase of the ligand denticity (for instance in the case of the use of ter-pyridine) favour the selectivity without improving the complexation. The selectivity difference for the complexation of actinides(III) and lanthanides(III) by the different studied ligands (independent systems) has been confirmed by experiments of inter-metals competition. (O.M.)

  2. Structural study and crystallography of the major compound of anhydrous cement: tri-calcium silicate; Etude structurale et cristallographie du compose majoritaire du ciment anhydre: le silicate tricalcique

    Energy Technology Data Exchange (ETDEWEB)

    Noirfontaine, M.N. de

    2000-01-01

    Anhydrous (Portland) cement is mainly composed of a synthetic material, the clinker, whose major compound is tri-calcium silicate (Ca{sub 3}SiO{sub 5}), often referred as C{sub 3}S with the compact oxides notations, C = CaO et S = SiO{sub 2}. The polymorphism of C{sub 3}S, still not well known, is the main subject of the thesis. Various crystal structures (rhombohedral R, monoclinic M1, M2, M3 and triclinic T1, T2, T3) can be found, depending on temperature and impurities. The only known structures are T1, M1 and M3, involving large unit cells with an orientational disorder of silicate tetrahedra. The single crystal studies exhibit no clear relation between the various polymorphs. Starting from known results from literature single crystal experiments, we establish the metric and structural relations between the different structures. Averaged structures for the T1, M1 and M3 polymorphs are proposed, together with all the matrices of transformation between the unit cells. We also introduce new 1-D, 2-D, and 3-D structural units, which make easier the understanding of the structures of C{sub 3}S, with the result of a better description of the orientational disorder. The effects of impurities on the structure are discussed. In industrial clinkers, impurities stabilize mainly M1 and M3 monoclinic forms. We propose a space group (Pc) and two structural models (a superstructure and an approximate averaged structure) for the M1 form. All the models are validated on synthetic compounds (M3, M2, M1 et T1) and industrial clinkers analysed by X-Ray powder diffraction with Rietveld analysis. (author)

  3. Molecular dynamics simulations of ter-pyridine and bis-triazinyl-pyridine complexes with lanthanide cations; Etude de dynamique moleculaire de complexes de la bis-triazinyl-pyridine (BTP) et de la terpyridine avec des lanthanides(3)

    Energy Technology Data Exchange (ETDEWEB)

    Guilbaud, Ph. [CEA Valrho, (DCC/DRRV/SEMP), 30 - Marcoule (France)

    2000-07-01

    The search for ligands which specifically separate actinides(III) from lanthanides(III) by liquid-liquid extraction has prompted considerable research in the Process Design and Modeling Department ('Service d'Etude et de Modelisation des Procedes'- SEMP). Ligands with soft donor atoms AS) that are able to perform this separation have already been investigated and research is currently under way to improve their performance for high acidic feeds. Theoretical chemistry research is conducted in the Theoretical and Structural Chemistry Laboratory ('Laboratoire de Chimie Theorique et Structurale') to improve our understanding of the complexation and extraction of these cations with such ligands. Theoretical studies were first carried out for the ter-pyridine (TPY) and bis-triazinyl-pyridine (BTP) ligands that display fairly good ability to separate and extract actinide(III) from lanthanide(III) ions. Molecular dynamics simulations were performed on ter-pyridine and bis-triazinyl-pyridine complexes with three lanthanide cations (La{sup 3+}, Eu{sup 3+} and Lu{sup 3+}) for vacuum and for water solutions. These calculations were carried out without counter-ions, with three nitrate (NO{sub 3}{sup -}) ions, and, in the case of ter-pyridine, with three {alpha}-bromo-caprate anions that are likely to be used experimentally as synergistic agents for the separation and extraction of An(III) from Ln(III). Molecular dynamics simulations were first performed for vacuum to evaluate the distances between nitrogen and lanthanide atoms (Ln{sup 3+},N) and intrinsic interaction energies to poly-nitrogenous ligands with or without NO{sub 3} ions, and for both ligands. The (Ln{sup 3+},N) distances decrease and the cation/ligand interaction energies increase along the La{sup 3+}, Eu{sup 3+}, Lu{sup 3+} series, with decreasing Ln(III) ion radii. The introduction of nitrate counter-ions makes the (Ln{sup 3+},N) distances slightly higher, and the TPY/Ln{sup 3+} and BTP

  4. Folds and Etudes

    Science.gov (United States)

    Bean, Robert

    2007-01-01

    In this article, the author talks about "Folds" and "Etudes" which are images derived from anonymous typing exercises that he found in a used copy of "Touch Typing Made Simple". "Etudes" refers to the musical tradition of studies for a solo instrument, which is a typewriter. Typing exercises are repetitive attempts to type words and phrases…

  5. Effect of nitrapyrin on emission of nitrous oxide from soil fertilized with anhydrous ammonia

    Science.gov (United States)

    Bremner, J. M.; Breitenbeck, G. A.; Blackmer, A. M.

    1981-04-01

    Field studies using a chamber technique to measure emissions of nitrous oxide (N2O) showed that the N2O emissions induced by fertilization of soil with anhydrous ammonia (180 kg N ha-1) were markedly reduced by addition of nitrapyrin [2-chloro-6-(trichloromethyl)-pyridine] to this fertilizer. The emission of N2O induced by application of anhydrous ammonia in the fall was reduced 63% by addition of nitrapyrin at the rate of 0.56 kg ha-1. The corresponding reduction when nitrapyrin was added to anhydrous ammonia applied in the spring was 87%. These observations indicate that nitrapyrin has potential value for reduction of the N2O emissions induced by nitrogen fertilization of soils and the possible adverse effects of these emissions on our climate.

  6. Anhydrous Taphole Mix for Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan

    2010-01-01

    @@ 1 Scope This standard specifies the term,definition,brand,label,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of anhydrous taphole mix for blast furnace.

  7. 21 CFR 573.180 - Anhydrous ammonia.

    Science.gov (United States)

    2010-04-01

    ... silage. (2)(i) The food additive anhydrous ammonia is applied directly to corn plant material for use in... to corn plant material containing 28 to 38 percent dry matter. (iv) The silage treated with...

  8. 7 CFR 58.325 - Anhydrous milkfat.

    Science.gov (United States)

    2010-01-01

    ... eligible for official certification, the anhydrous milkfat shall be made by a continuous separation process directly from milk or cream. The cream used shall be comparable to the flavor quality specified above for...

  9. NQR frequencies of anhydrous carbamazepine polymorphic phases

    CERN Document Server

    Bonin, C J; Pusiol, D J

    2010-01-01

    In this work we propose the Nuclear Quadrupole Resonance (NQR) technique as an analytical method suitable for polymorphism detection in active parts (or active principles) of pharmaceuticals with high pharmacological risk. Samples of powder carbamazepine (5H-dibenz(b,f)-azepine-5-carboxamide) are studied. In its anhydrous state, this compound presents at least three different polymorphic forms: form III, the commercial one, form II, and form I. Of these, only form III possesses desirable therapeutic effects. By using the NQR technique, it was possible to characterize two of the three polymorphic phases (I and III) for anhydrous carbamazepine in few minutes at room temperature, detecting the characteristic frequencies of 14N nuclei (I=1) present in their chemical composition and in the frequency range 2.820-3.935 MHz. For form II, characteristic lines were not detected within this range of frequencies. The lines detected for form III are centered at the frequencies \

  10. Demethylation of Quinine Using Anhydrous Aluminium Trichloride

    OpenAIRE

    Aiyi Asnawi; As’ari Nawawi; Rahmana Emran Kartasasmita; Slamet Ibrahim3)

    2011-01-01

    Quinine is a natural alkaloid having a methoxy group bound to quinoline ring and an allyl group bound to quinuclidine ring. Demethylation of quinine applying strong acid such as HBr or HI at high temperature was unsuccessful. The aim of this research was to obtain demethylated quinine by means of mild and selective demethylation procedure to prevent the addition reaction of allyl group. Selective demethylation of quinine has been carried out using anhydrous aluminium trichloride as reagent. T...

  11. The use of anhydrous ammonia for bioventing

    Energy Technology Data Exchange (ETDEWEB)

    Zytner, R.G.; Hallman, M.; Gimenez, B.F.; Jennings, R.; Leek, K. [Guelph Univ., ON (Canada). Faculty of Graduate Studies

    2002-07-01

    Soils contaminated with hydrocarbons can be effectively treated using bioventing remediation technology, an ideal method for removing residual contamination left by soil vapour extraction (SVE). Bioventing uses low or intermitted air flow rates to produce oxygen-rich conditions in the vadose zone, thereby promoting the formation of micro-organisms that can mineralize the hydrocarbons if enough nutrients are present. There is concern regarding the use of nutrients (the addition of nitrogen) to the subsurface because current applications methods cannot uniformly disperse nitrogen throughout the entire subsurface. Two research studies are being conducted using gasoline contaminated soil to address this concern. The first phase of the study focuses on how to best deliver nitrogen to the subsurface. Injecting anhydrous ammonia into the contaminated surface was one suggestion for stimulating the growth of hydrocarbon degraders. SVE extraction well models indicated this was an effective and safe way to disperse nitrogen. The second phase of the study involved the use of respirometers to compare total petroleum hydrocarbon (TPH) degradation with nitrogen additions in the form of NH{sub 4}Cl or anhydrous ammonia. The respirometers were run for about 1 month after which time it was determined that the use of anhydrous ammonia is an effective method to promote bioventing.

  12. An element with a liquid, anhydrous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Nankay, S.; Indzima, T.; Toyeguti, Y.

    1982-09-01

    A liquid anhydrous element and a heat treated Mn0/sub 2/ cathode, to which sodium silicate in the form of Na/sub 2/0 with 5/2Si0/sub 2/ liquid glass is added in a volume of 3 grams per 100 grams of Mn0/sub 2/ is used in the element with a light metal, lithium type anode. Moreover 4.5 grams of acetylene soot is added to the active cathode mass. A fluorine bearing resin is used as the binder. The cathode stores well.

  13. Pyrimidine-pyridine ring interconversion

    NARCIS (Netherlands)

    Plas, van der H.C.

    2003-01-01

    This chapter discusses the pyrimidine-to-pyridine ring transformation and pyridine-to-pyrimidine ring transformation. In nucleophile-induced pyrimidine-to-pyridine rearrangements, two types of reactions can be distinguished depending on the structure of the nucleophile: (1) reactions in which the ni

  14. Parallel interactions at large horizontal displacement in pyridine-pyridine and benzene-pyridine dimers.

    Science.gov (United States)

    Ninković, Dragan B; Andrić, Jelena M; Zarić, Snežana D

    2013-01-14

    A study of crystal structures from the Cambridge Structural Database (CSD) and DFT calculations reveals that parallel pyridine-pyridine and benzene-pyridine interactions at large horizontal displacements (offsets) can be important, similar to parallel benzene-benzene interactions. In the crystal structures from the CSD preferred parallel pyridine-pyridine interactions were observed at a large horizontal displacement (4.0-6.0 Å) and not at an offset of 1.5 Å with the lowest calculated energy. The calculated interaction energies for pyridine-pyridine and benzene-pyridine dimers at a large offset (4.5 Å) are about 2.2 and 2.1 kcal mol(-1), respectively. Substantial attraction at large offset values is a consequence of the balance between repulsion and dispersion. That is, dispersion at large offsets is reduced, however, repulsion is also reduced at large offsets, resulting in attractive interactions.

  15. Polyvinyl pyridine microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1980-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  16. Sodium Picosulfate, Magnesium Oxide, and Anhydrous Citric Acid

    Science.gov (United States)

    Sodium picosulfate, magnesium oxide, and anhydrous citric acid combination powder is used to empty the colon (large ... clear view of the walls of the colon. Sodium picosulfate is in a class of medications called ...

  17. 3-(Pyridin-2-ylcoumarin

    Directory of Open Access Journals (Sweden)

    Yu-Xia Da

    2010-11-01

    Full Text Available In the title compound, C14H9NO2, the dihedral angle between the pyridine ring and the lactone ring is 10.40 (3°. The coumarin ring system is nearly planar, with a dihedral angle of 1.40 (2° between the lactone and benzene rings. An intramolecular C—H...O hydrogen bond occurs. In the crystal, inversion dimers linked by pairs of C—H...O interactions occur, generating R22(14 loops.

  18. A fixed cations and low Tg polymer: the poly(4-vinyl-pyridine) quaternized by poly(ethylene oxide) links. Conductivity study; Un electrolyte polymere a cations fixes et bas Tg: les poly(4-vinylpyridine) quaternisees par des chainons de poly(oxyde d`ethylene). Etude de la conductivite

    Energy Technology Data Exchange (ETDEWEB)

    Gramain, Ph. [Ecole Nationale Superieure de Chimie de Montpellier, 34 (France); Frere, Y. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Institut Charles Sadron

    1996-12-31

    The spontaneous ionic polymerization of 4-vinyl-pyridine in presence of mono-tosylated or bromated short chains of poly(ethylene oxide)-(PEO) is used to prepare amorphous comb-like poly-cations with low Tg. The polymer electrolyte properties of these new structures have been studied without any addition of salts. The ionic conductivity of these fixed cation poly-electrolytes depends on the length of the grafted PEO and varies from 10{sup -7} to 10{sup -4} S/cm between 25 and 80 deg. C. It is only weakly dependent on the nature of the cation but it is controlled by the movements of the pyridinium cation which are facilitated by the plastifying effect of the POE chains which do not directly participate to the ionic transport. (J.S.) 17 refs.

  19. 27 CFR 21.122 - Pyridine bases.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Pyridine bases. 21.122....122 Pyridine bases. (a) Alkalinity. One ml of pyridine bases dissolved in 10 ml of water is titrated.... Dissolve 1 ml of pyridine bases in 100 ml of water. (1) Ten ml of this solution are treated with 5 ml of...

  20. Pyridine Aggregation in Helium Nanodroplets

    Science.gov (United States)

    Nieto, Pablo; Poerschke, Torsten; Habig, Daniel; Schwaab, Gerhard; Havenith, Martina

    2012-06-01

    Pyridine crystals show the unusual property of isotopic polymorphism. Experimentally it has been observed that deuterated pyridine crystals exist in two phases while non-deuterated pyridine does not show a phase transition. Therefore, although isotopic substitution is the smallest possible modification of a molecule it greatly affects the stability of pyridine crystals. A possible experimental approach in order to understand this striking effect might be the study of pyridine aggregation for small clusters. By embedding the clusters in helium nanodroplets the aggregates can be stabilized and studied by means of Infrared Depletion Spectroscopy. Pyridine oligomers were investigated in the C-H asymmetric vibration region (2980-3100 cm-1) using this experimental technique. The number of molecules for the clusters responsibles for each band were determined by means of pick-up curves as well as mass sensitive depletion spectra. Furthermore, the intensity dependence of the different bands on applying a dc electric field was studied. The assignment of the different structures for pyridine clusters on the basis of these measurements were also carried out. S. Crawford et al., Angew. Chem. Int. Ed., 48, 755 (2009).

  1. Basicity of pyridine and some substituted pyridines in ionic liquids.

    Science.gov (United States)

    Angelini, Guido; De Maria, Paolo; Chiappe, Cinzia; Fontana, Antonella; Pierini, Marco; Siani, Gabriella

    2010-06-04

    The equilibrium constants for ion pair formation of some pyridines have been evaluated by spectrophotometric titration with trifluoroacetic acid in different ionic liquids. The basicity order is the same in ionic liquids and in water. The substituent effect on the equilibrium constant has been discussed in terms of the Hammett equation. Pyridine basicity appears to be less sensitive to the substituent effect in ionic liquids than in water.

  2. Preparation of anhydrous lanthanum bromide for scintillation crystal growth

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tong; LI Hongwei; ZHAO Chunlei; YU Jinqiu; HU Yunsheng; CUI Lei; HE Huaqiang

    2012-01-01

    This paper reported an efficient and economical method for preparation of anhydrous LaBr3 for scintillation crystal growth.High purity anhydrous LaBr3 powders in large quantities were successfully obtained by stepped dehydration of LaBr3·7H2O using NH4Br as additive.Experiments revealed that adding proper amount of NH4Br could effectively restrain the hydrolysis of LaBr3 during dehydration and thus decreased the yield of deleterious impurity of LaOBr.Optimum preparation conditions,including the amount of NH4Br in use,the dehydration temperature and atmosphere,were investigated by DTA/TG and water/oxygen analysis.The Raman characterization of the as-prepared anhydrous LaBr3 was also presented.

  3. Molecular dynamics simulation of pyridine

    Science.gov (United States)

    Trumpakaj, Zygmunt; Linde, Bogumił

    2015-04-01

    Molecular Dynamics (MD) simulations are used for the investigation of molecular motions in pyridine in the temperature range 20-480 K under normal pressure. The results obtained are analyzed within the frame of the Mori Zwanzig memory function formalism. An analytical approximation of the first memory function K(t) is applied to predict some dependences on temperature. Experimental results of the Rayleigh scattering of depolarized light from liquid pyridine are used as the main base for the comparison.

  4. [Zn(sulfasalazine)2(pyridine)

    Institute of Scientific and Technical Information of China (English)

    王锡森; 宋玉梅; 熊仁根

    2005-01-01

    In compound [Zn(sulfasalazine)2(pyridine)] (1), each zinc atom not only coordinates to nitrogen atom of pyridine, but also is connected with four oxygen atoms from carboxylic acid groups of four sulfasalazine ligands,to result in the formation of a distorted tetragonal pyramid. In addition, each sulfasalazine ligand coordinates to two zinc atoms through its two oxygen atoms of carboxylic acid group to afford a 1D chain. CCDC: 274842.

  5. Criticality studies; Etudes de criticite

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D.; Lecorche, P.; Clouet d' Orval, Ch. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Criticality studies made at the Commissariat a l'Energie atomique deal on the one hand with experiments on plutonium and uranium solutions, on the other hand with theoretical work on the development and use of computation, methods for the resolution of problems concerning the nuclear safety of chemical and metallurgical plants. I - Since 1958 the experimental studies have dealt with homogeneous media constituted by a fissile salt dissolved in light water. Developed using the reactor Proserpine, the experiments have been carried on at Saclay on the Alecto assemblies where solutions of plutonium or of 90 p.100 - enriched uranium can be made critical. The results already obtained relate to critical masses of cylindrical tanks of diameters from 20 to 50 cm. reflected in several ways (water, concrete, etc. . ) at concentrations up to 100 g/liter. Physical measurements (spectra, reactor noises) and interaction measurements complete the results. Other experiments relating to plutonium solutions were begun in 1963, at the Valduc Center. They deal with the study of critical masses of annular vessels of external diameter 50 cm and internal diameter varying from 10 to 30 cm. These vessels can be water reflected internally, externally, or both. Two of these vessels have been studied in interaction for various geometries. Slabs of various thicknesses were also studied. II - The studies thus undertaken allowed the development of methods of computation which have been tested on several experiments. Particular use has been made of the possibilities of calculations based on transport theory and on Monte Carlo methods. All these theoretical studies are applied to the design and control of industrial plants from the point of view of safety. (authors) [French] Les etudes de criticite effectuees au CEA comportent d'une part des experiences sur des solutions de plutonium et d'uranium enrichi, d'autre part des travaux theoriques portant sur la mise au point et l

  6. Compact anhydrous HCl to aqueous HCl conversion system

    Science.gov (United States)

    Grossman, M.W.; Speer, R.

    1993-06-01

    The present invention is directed to an inexpensive and compact apparatus adapted for use with a [sup 196]Hg isotope separation process and the conversion of anhydrous HCl to aqueous HCl without the use of air flow to carry the HCl vapor into the converter system.

  7. Process for the production of sodium carbonate anhydrate

    NARCIS (Netherlands)

    Oosterhof, H.; Van Rosmalen, G.M.; Witkamp, G.J.; De Graauw, J.

    2000-01-01

    The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m<3>, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of

  8. Solid state interconversion between anhydrous norfloxacin and its hydrates.

    Science.gov (United States)

    Chongcharoen, Wanchai; Byrn, Stephen R; Sutanthavibul, Narueporn

    2008-01-01

    This work is focused on characterizing and evaluating the solid state interconversion of norfloxacin (NF) hydrates. Four stoichiometric NF hydrates, dihydrate, hemipentahydrate, trihydrate, pentahydrate and a disordered NF state, were generated by various methods and characterized by X-ray powder diffractometry (XRPD), thermal analysis and Karl Fisher titrimetry. XRPD patterns of all NF hydrates exhibited crystalline structures. NF hydrate conversion was studied with respect to mild elevated temperature and various degrees of moisture levels. NF hydrates transformed to anhydrous NF Form A after gentle heating at 60 degrees C for 48 h except dihydrate and trihydrate where mixture in XRPD patterns between anhydrous NF Form A and former structures existed. Desiccation of NF hydrates at 0% RH for 7 days resulted in only partial removal of water molecules from the hydrated structures. The hydrated transitional phase and the disordered NF state were obtained from the incomplete dehydration of NF hydrates after thermal treatment and pentahydrate NF after desiccation, respectively. Anhydrous NF Form A and NF hydrates transformed to pentahydrate NF when exposed to high moisture environment except dihydrate. In conclusion, surrounding moisture levels, temperatures and the duration of exposure strongly influenced the interconversion pathways and stoichiometry of anhydrous NF and its hydrates. (c) 2007 Wiley-Liss, Inc.

  9. 49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

  10. 7 CFR 51.1178 - Maximum anhydrous citric acid permissible for corresponding total soluble solids.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Maximum anhydrous citric acid permissible for... Sinensis (l) Osbeck) § 51.1178 Maximum anhydrous citric acid permissible for corresponding total soluble solids. For determining the grade of juice, the maximum permissible anhydrous citric acid content...

  11. 40 CFR 721.8775 - Substituted pyridines.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridines. 721.8775... Substances § 721.8775 Substituted pyridines. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted pyridine (PMN P-84-1219)...

  12. 40 CFR 721.8675 - Halogenated pyridines.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated pyridines. 721.8675... Substances § 721.8675 Halogenated pyridines. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as halogenated pyridine (PMN P-83-1163)...

  13. Method of synthesis of anhydrous thorium(IV) complexes

    Science.gov (United States)

    Kiplinger, Jaqueline L; Cantat, Thibault

    2013-04-30

    Method of producing anhydrous thorium(IV) tetrahalide complexes, utilizing Th(NO.sub.3).sub.4(H.sub.2O).sub.x, where x is at least 4, as a reagent; method of producing thorium-containing complexes utilizing ThCl.sub.4(DME).sub.2 as a precursor; method of producing purified ThCl.sub.4(ligand).sub.x compounds, where x is from 2 to 9; and novel compounds having the structures: ##STR00001##

  14. UV photolysis for accelerating pyridine biodegradation.

    Science.gov (United States)

    Zhang, Yongming; Chang, Ling; Yan, Ning; Tang, Yingxia; Liu, Rui; Rittmann, Bruce E

    2014-01-01

    Pyridine, a nitrogen-containing heterocyclic compound, is slowly biodegradable, and coupling biodegradation with UV photolysis is a potential means to accelerate its biotransformation and mineralization. The initial steps of pyridine biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. We employed an internal circulation baffled biofilm reactor for pyridine biodegradation following three protocols: direct biodegradation (B), biodegradation after photolysis (P+B), and biodegradation with succinic acid added (B+S). Succinic acid was the main UV-photolysis product from pyridine, and its catabolic oxidation generates internal electron carriers that may accelerate the initial steps of pyridine biodegradation. Compared with direct biodegradation of pyridine (B), the removal rate for the same concentration of photolyzed pyridine (P+B) was higher by 15 to 43%, depending on the initial pyridine concentrations (increasing through the range of 130 to 310 mg/L). Adding succinic acid alone (B+S) gave results similar to P+B, which supports that succinic acid was the main agent for accelerating the pyridine biodegradation rate. In addition, protocols P+B and B+S were similar in terms of increasing pyridine mineralization over 10 h: 84% and 87%, respectively, which were higher than with protocol B (72%). The positive impact of succinic acid-whether added directly or produced via UV photolysis-confirms that its catabolism, which produced intracellular electron carriers, accelerated the initial steps of pyridine biotransformation.

  15. Etude Sedimentologique et Esquisse Paleoenvironnementale des ...

    African Journals Online (AJOL)

    Etude Sedimentologique et Esquisse Paleoenvironnementale des ... Les analyses sédimentologiques réalisées dans ce travail, sont un prélude d'un projet d'études pluridisciplinaires ... (Crétacé inférieur) à l'océanisation complète (fin.

  16. Les Etudes De Langues Aux Pays-Bas

    NARCIS (Netherlands)

    Zwarts, F.

    1995-01-01

    Les Etudes de Langues dans l'Enseignement Superieur en Europe: Des Rapports Nationaux Préparés pour une Conference sur les Etudes de Langues en Europe et Cooperation dans le Domaine de l'Enseignement Superieur à l'Univerité de Stockholm.

  17. Highly Regioselective Halogenation of Pyridine N-Oxide: Practical Access to 2-Halo-Substituted Pyridines.

    Science.gov (United States)

    Chen, Ying; Huang, Jinkun; Hwang, Tsang-Lin; Chen, Maosheng J; Tedrow, Jason S; Farrell, Robert P; Bio, Matthew M; Cui, Sheng

    2015-06-19

    A highly efficient and regioselective halogenation reaction of unsymmetrical pyridine N-oxide under mild conditions is described. The methodology provides a practical access to various 2-halo-substituted pyridines, which are pharmaceutically important intermediates.

  18. [Biodegradation of pyridine under UV irradiation].

    Science.gov (United States)

    Fang, Miao-Miao; Yan, Ning; Zhang, Yong-Ming

    2012-02-01

    Pyridine, a complex nitrogen-containing heterocyclic compounds, is usually difficult to degrade by means of single biological method. The internal loop photobiodegradation reactor (ILPBR) was used for degradation of pyridine in batch and continuous experiments following three protocols: photolysis alone (P), biodegradation alone (B), and intimately coupled photolysis and biodegradation (P&B) to investigate the regularity of pyridine degradation. The experimental results indicated that pyridine removal rate by P&B was fastest among three protocols in batch experiment, in which protocol B was faster than P. For initial pyridine concentration of 100 mg L(-1), the pyridine removal rates were respectively 4.95, 10.2 and 14.58 mg (L x h)(-1) corresponding to protocol P, B and P&B. Pyridine degradation kinetic equations were established based on Monod model, and the saturation constants decreased from 1920.4 mg x L(-1) for protocol B to 1094.1 mg x L(-1) for protocol P&B. Protocols P, B and P&B were also used for pyridine degradation in continuous flow and influent pyridine concentration increased from 50 to 300 mg x L(-1), and their average removal rates were respectively 15.8 mg (L x h)(-1) for protocol P, 23.1 mg x (L x h)(-1) for protocol B and 24.9 mg x (L x h)(-1) for protocol P&B, in which the removal rates were higher than that in batch. Experiments suggested that the inhibition of pyridine to biofilm could be relieved due to UV irradiation in process of intimately coupled UV photolysis and biodegradation, and biofilm had kept its bioactivity degrading pyridine and enhanced pyridine removal rates.

  19. Bacterial pyridine hydroxylation is ubiquitous in environment.

    Science.gov (United States)

    Sun, Ji-Quan; Xu, Lian; Tang, Yue-Qin; Chen, Fu-Ming; Zhao, Jing-Jing; Wu, Xiao-Lei

    2014-01-01

    Ten phenol-degrading bacterial strains were isolated from three geographically distant environments. Five of them, identified as Diaphorobacter, Acidovorax, Acinetobacter (two strains), and Corynebacterium, could additionally transform pyridine, through the transcription of phenol hydroxylase genes induced both by phenol and pyridine. HPLC-UV and LC-MS analyses indicated that one metabolite (m/e = 96.07) with the same molecular weight as monohydroxylated pyridine was produced from the five phenol-degrading strains, when pyridine was the sole carbon source. Phenol (50 mg l(-1)) could initially inhibit and later stimulate the pyridine transformation. In addition, heterologous expression of the phenol hydroxylase gene (pheKLMNOP) resulted in the detection of monohydroxylated pyridine, which confirmed the phenol hydroxylase could catalyze pyridine hydroxylation. Phylogeny of the phenol hydroxylase genes revealed that the genes from the five pyridine-hydroxylating strains form a clade with each other and with those catalyzing the hydroxylation of phenol, BTEX (acronym of benzene, toluene, ethylbenzene, and xylene), and trichloroethylene. These results suggest that pyridine transformation via hydroxylation by phenol hydroxylase may be prevalent in environments than expected.

  20. Formulation and in vitro evaluation of theophylline anhydrous bioadhesive tablets

    Directory of Open Access Journals (Sweden)

    Deshmukh V

    2009-01-01

    Full Text Available The aim of the current study was to design oral controlled release (CR theophylline anhydrous bioadhesive tablets and to optimize the drug release profile and in vitro bioadhesion strength. Different types of natural hydrophilic polymers such as xanthun gum, locust bean gum, guar gum, karaya gum, and their combinations were used to formulate matrix tablets. Tablets of anhydrous theophylline were prepared by the direct compression method and were subjected to in vitro drug dissolution for 12 hours using the USP dissolution apparatus basket type at a speed of 100 rpm and temperature of 37 ± 0.5°C using gastric fluid (pH 1.2. The bioadhesive strength of the tablets was measured as the force of detachment against the porcine gastric mucosa. The in vitro release study as well as the retention time of the bioadhesive tablets on the mucous membrane were investigated to develop a bioadhesive polymer-based CR delivery system and to evaluate the performance of such a delivery device. The combination of karaya gum:guar gum (6:4 tablet showed a greater bioadhesive strength as compared with a single gum and other gum combination tablets. Karaya gum:guar gum-loaded tablets were not discharged from the mucous membrane and were dissolved in the gastric fluid. An increase in the gum concentration increases the drug release profile beyond 12 hours whereas there is no significant effect of gum concentration on the bioadhesive strength of the tablet.

  1. A New Thickener for CO2 Anhydrous Fracturing Fluid

    Directory of Open Access Journals (Sweden)

    Zhang Jian

    2015-01-01

    Full Text Available CO2 dry fracturing technology is well-known for its advantages. Little water is used in this technology, which is able to ease the pressure of consumption on water resources. Many abroad theoretical researches, laboratory experiments and field tests have been taken to explore the yield mechanism, the adaptability and the technology of pure liquid CO2 fracturing. These achievements have been applied to a variety of reservoirs transformation and improven the effectiveness of stimulation treatment in a degree. The researches and studies in the domestic didn’t get popular until recent years. Thus, this article firstly introduces the main development and application about pure CO2 anhydrous fracturing technology, and sums up the effect and evaluation of its fluid through application examples both in the domestic and abroad. However, although this technology has many excellent qualities, but systematic studies indicate that its proppant-carrying capacity is less competitive because of the low viscosity of pure CO2 liquid and other reasons. In a consequence, it is necessary to develop an appropriate thickener for CO2 anhydrous fracturing fluid to improve its carrying capacity. Then this article describes some studies of previous scholars about CO2 thickener. Then we put forward our own research ideas and transform it into actual experiments. Thanks to the valid performances of these tests, we successfully develop a thickener X and cosolvent B.

  2. Anhydrous crystals of DNA bases are wide gap semiconductors.

    Science.gov (United States)

    Maia, F F; Freire, V N; Caetano, E W S; Azevedo, D L; Sales, F A M; Albuquerque, E L

    2011-05-07

    We present the structural, electronic, and optical properties of anhydrous crystals of DNA nucleobases (guanine, adenine, cytosine, and thymine) found after DFT (Density Functional Theory) calculations within the local density approximation, as well as experimental measurements of optical absorption for powders of these crystals. Guanine and cytosine (adenine and thymine) anhydrous crystals are predicted from the DFT simulations to be direct (indirect) band gap semiconductors, with values 2.68 eV and 3.30 eV (2.83 eV and 3.22 eV), respectively, while the experimentally estimated band gaps we have measured are 3.83 eV and 3.84 eV (3.89 eV and 4.07 eV), in the same order. The electronic effective masses we have obtained at band extremes show that, at low temperatures, these crystals behave like wide gap semiconductors for electrons moving along the nucleobases stacking direction, while the hole transport are somewhat limited. Lastly, the calculated electronic dielectric functions of DNA nucleobases crystals in the parallel and perpendicular directions to the stacking planes exhibit a high degree of anisotropy (except cytosine), in agreement with published experimental results.

  3. Vibrational studies of benzene, pyridine, pyridine-N-oxide and their cations.

    Science.gov (United States)

    Kumar, M; Srivastava, Mayuri; Yadav, R A

    2013-07-01

    IR and Raman spectra of pyridine and pyridine-N-oxide have been recorded and analyzed. The optimized molecular geometries, APT charges and vibrational characteristics for benzene, pyridine, pyridine-N-oxide and their cations have been computed using DFT method. Due to attachment of O atom at N site or removal of electron all the modes are affected in magnitudes. However, significant changes are noticed in their IR intensities, Raman activities and depolarization ratios of the Raman bands in going from pyridine to its N-oxide or in going from neutrals to their cations. It is interesting to note that in going from benzene to benzene cation charge redistribution takes place to reduce the symmetry from D6h to D2h. The calculated frequencies have been correlated with the experimental frequencies for the pyridine and pyridine-N-oxide molecules.

  4. 5-(Pyridin-4-ylisophthalic acid

    Directory of Open Access Journals (Sweden)

    Yong-Fang Zhang

    2010-11-01

    Full Text Available In the title compound, C13H9NO4, the two carboxylic groups and the benzene ring are approximately co-planar with a maximum atomic deviation 0.175 (4 Å, while the pyridine ring is oriented at a dihedral angle of 31.07 (18° with respect to the benzene ring. In the crystal, molecules are linked by O—H...O, O—H...N and weak C—H...O hydrogen bonds, forming a three-dimensional supramolecular framework.

  5. Acid-base strengths in pyridine

    NARCIS (Netherlands)

    Bos, M.; Dahmen, E.A.M.F.

    1971-01-01

    Although pyridine is a solvent with a low dielectric constant, spectrophotometric determinations show simple dissociation without ion pairs as intermediates for some sulfonphthaleins and polynitrophenols in pyridine. The salts of a number of amines and hydrochloric acid, perchloric acid and picric

  6. 7 CFR 58.715 - Cream, plastic cream and anhydrous milkfat.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cream, plastic cream and anhydrous milkfat. 58.715 Section 58.715 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... Service 1 Quality Specifications for Raw Material § 58.715 Cream, plastic cream and anhydrous...

  7. Riboflavin production during growth of Micrococcus luteus on pyridine

    Energy Technology Data Exchange (ETDEWEB)

    Sims, G.K. (Environmental Chemistry Lab., Dow Elanco, Midland, MI (United States)); O' Loughlin, E.J. (Ohio State Univ., Columbus (United States))

    1992-10-01

    Micrococcus luteus produced 29 {mu}M riboflavin during growth on 6.5 mM pyridine but not during growth on other substrates. On the basic of the results of radiolabelling studies, riboflavin was not directly synthesized from pyridine. Pyridine may interfere with riboflavin biosynthesis or elicit a general stress response in M. luteus. The optimum concentration of pyridine for both growth of the organism and pyridine degradation was 13 mM. Above 25 mM, pyridine temporarily inhibited growth, pyridine degradation, oxygen uptake, and pigment production.

  8. The Contrasting Alkylations of 4-(Dimethylaminomethyl)pyridine and 4-(Dimethylamino)pyridine: An Organic Chemistry Experiment

    Science.gov (United States)

    Jantzi, Kevin L.; Wiltrakis, Susan; Wolf, Lauren; Weber, Anna; Cardinal, Josh; Krieter, Katie

    2011-01-01

    A critical factor for the increased nucleophilicity of the pyridine nitrogen in 4-(dimethylamino)pyridine (DMAP) is electron donation via resonance from the amino group into the aromatic ring that increases electron density on the pyridine nitrogen. To explore how important this resonance effect is, 4-(dimethylaminomethyl)pyridine (DMAMP) was…

  9. Dihydrogen phosphate-water tape and layers vs dihydrogen phosphate layers tuned by hydrophobic isomeric pyridine-diamine functionalized molecules

    Science.gov (United States)

    Huang, Jing; Liu, Tong-Peng; Huo, Li-Hua; Deng, Zhao-Peng; Gao, Shan

    2017-01-01

    Assembly of six isomeric pyridine-diamine-based molecules, N,N‧-bis(pyridin-4-ylmethyl)ethane-1,2-diamine (M1), N,N‧-bis(pyridin-3-ylmethyl)ethane-1,2-diamine (M2), N,N‧-bis(pyridin-2-ylmethyl)ethane-1,2-diamine (M3), N,N‧-bis(pyridin-4-ylmethyl)propane-1,3-diamine (M4), N,N‧-bis(pyridin-3-ylmethyl)propane-1,2-diamine (M5), and N,N‧-bis(pyridin-2-ylmethyl)propane-1,3-diamine (M6), with phosphoric acid (H3PO4) in different ratio (1:2 and 1:4), leads to the formation of nine salts, H2M12+·2H2PO4-·4H2O (1), H2M22+·2H2PO4-·2H2O (2), H2M32+·2H2PO4-·2H2O (3), H4M14+·4H2PO4- (4), H4M24+·4H2PO4- (5), H4M34+·4H2PO4- (6), H2M42+·2H2PO4-·3H2O (7), 2H2M52+·4H2PO4-·2H3PO4 (8), and H2M62+·2H2PO4- (9), which have been characterized by elemental analysis, IR, TG, PL, powder and single-crystal X-ray diffraction. Structural analyses indicate that hydrogen-bonding patterns of H2PO4- anions, conformation of protonated cations can effectively influence the supramolecular architectures through diverse non-covalent interactions. Hydrous salts 1-3 and 7 present 2D and 3D host-guest supramolecular networks, in which the connection of H2PO4- anions and water molecules generates diverse tape and layer motifs. H2PO4- anions in anhydrous salts 4-6 interconnect with each other through hydrogen bonds to form two types of layers, which are joined by discrete H4M4+ cations into 3D inorganic-organic hybrid supramolecular networks. Salts 8-9 also present 2D and 3D host-guest supramolecular networks where the interconnection of H2PO4- anions and its combination with H3PO4 molecules leads to diverse layers. Luminescent analyses indicate that salts 1-9 exhibit violet and blue emission maximum in the range of 390-467 nm at room temperature.

  10. Periodic quantum chemical studies on anhydrous and hydrated acid clinoptilolite.

    Science.gov (United States)

    Valdiviés Cruz, Karell; Lam, Anabel; Zicovich-Wilson, Claudio M

    2014-08-07

    Periodic quantum chemistry methods as implemented in the crystal09 code were considered to study acid clinoptilolite (HEU framework type), both anhydrous and hydrated. The most probable location of acid sites and water molecules together with other structural details has been the object of particular attention. Calculations were performed at hybrid and pristine DFT levels of theory with a VDZP quality basis set in order to compare performances. It arises that PBE0 provides the best agreement with experimental data as concerns structural features and the most stable Al distribution in the framework. The role of the water molecule distribution in the stability of the systems, the most probable structure that they induce in the material, and their eventual influence on further chemical modification processes, such as dealumination, are discussed in detail. Results show that, apart from the usually considered interactions of water molecules with the zeolite framework, that is, a H-bond with Brönsted acid sites and coordination with framework Al as Lewis ones, it is necessary to consider cooperation of other weaker effects so as to fully understand the hydration effect in this kind of materials.

  11. Laryngeal sequelae due to accidental inhalation of anhydrous ammonia

    Directory of Open Access Journals (Sweden)

    Cruz, Walter Paiva

    2009-03-01

    Full Text Available Introduction: Anhydrous Ammonia (AA is a caustic compound commonly used in the industry that can cause burns, even with brief contact. As with other alkali burns, the early washing to remove the AA from burnt areas is crucial to limit tissue damage. The concentration of toxic agent and duration of its contact determine the degree of skin and mucosa destruction. A tanker truck carrying AA (NH3 fell off a highway, and released a dense cloud of AA gas. Fifty-four people inhaled the gas and after ninety days, three people were still experiencing hoarseness and were examined. Case Report: We assessed three patients with laryngeal sequelae due to AA inhalation burn. We found a case of hyperemia and edema, one case of granuloma of the posterior third portion of the left vocal cord, and one case of vocal cord adhesion. Necropsy findings are commented both macroscopically and microscopically. The sequelae and the best treatments for them are discussed herein.

  12. Novel anhydrous emulsions: formulation as controlled release vehicles.

    Science.gov (United States)

    Suitthimeathegorn, Orawan; Jaitely, Vikas; Florence, Alexander T

    2005-07-25

    Novel anhydrous emulsions, which may offer some advantages as depot or reservoir vehicles for lipophilic drugs in controlled delivery systems, were formulated using castor oil as the disperse phase and dimethicone or cyclopentasiloxane as the continuous phase. Among the emulsifiers studied only silicone surfactants (cyclomethicone/dimethicone copolyols) which were miscible in silicone oil stabilized the emulsions. Cyclomethicone/PEG/PPG-18/18 Dimethicone and Cyclopentasiloxane/PEG/PPG-18/18 Dimethicone were more effective in lowering the interfacial tension between castor oil and both dimethicone and cyclopentasiloxane. Emulsions formulated using either of these two surfactants were found to be stable against phase separation and exhibited least globule growth over 168 h. The average particle size was found to be 2-6 microm in these systems formed by probe sonication. Slow release patterns of 3H-dehydroepiandrosterone (DHEA) and 3H-dexamethasone solubilized in the disperse castor oil phase into an aqueous dialyzing medium were observed over 48 h.

  13. Using microkinetic analysis to search for novel anhydrous formaldehyde production catalysts

    DEFF Research Database (Denmark)

    Li, Han-Jung; Lausche, Adam C.; Peterson, Andrew A.

    2015-01-01

    Abstract Direct dehydrogenation of methanol to produce anhydrous formaldehyde is investigated using periodic density functional theory (DFT) and combining the microkinetic model to estimate rates and selectivities on stepped (211) surfaces under a desired reaction condition. Binding energies...

  14. Activation of Anhydrate Phosphogypsmn by K2SO4 and Hemihydrate Gypsum

    Institute of Scientific and Technical Information of China (English)

    YANG Min; QIAN Jueshi

    2011-01-01

    Lime pretreated phosphogypsum(PG) was calcined at 500 ℃ to produce anhydrate gypsum cement.Due to the slow hydration of anhydrate gypsum,additives,K2SO4 and hemihydrate gypsum were selected to accelerate the hydration of anhydrate.The hydration characteristics,the resistance to hydrodynamic water,and the mineralogical studies were investigated.The experimental results suggest that activated by K2SO4 and hemihydrate,anhydrate PG hydrates much more rapidly than that in the presence of only K2SO4 or in the absence of additives.The binder has proper setting time,good strength development,and relatively better resistance to water.The hardened binder has hydrated products of rod or stick like shaped dihydrate gypsum crystals.

  15. Study on the Stability of DeoxyArbutin in an Anhydrous Emulsion System

    OpenAIRE

    Chiu-Wen Chen; Shu-Mei Lee; Yi-Shyan Chen; Pey-Shiuan Wu; Nai-Fang Chang; Chao-Hsun Yang; Chih-Chien Lin

    2011-01-01

    The skin-whitening agent, deoxyArbutin, is a potent tyrosinase inhibitor that is safer than hydroquinone and arbutin. However, it is thermolabile in aqueous solutions, where it decomposes to hydroquinone. Pharmaceutical and cosmetic emulsions are normally oil-in-water (o/w) or water-in-oil (w/o) systems; however, emulsions can be formulated with no aqueous phase to produce an anhydrous emulsion system. An anhydrous emulsion system could offer a stable vehicle for compounds that are sensitive ...

  16. A FOURIER TRANSFORM INFRARED SPECTROSCOPIC STUDY OF THE REACTION BETWEEN POLY (VINYL PYRIDINE)S AND EPOXY COMPOUNDS

    Institute of Scientific and Technical Information of China (English)

    XUE Gi; JIANG Shankeng

    1987-01-01

    Chemical reactions between poly (vinyl pyridine)s and 1,4-butanediol diglycidyl ether and other epoxy compounds were studied by Fouriertransform infrared spectroscopy and other techniques. The epoxy group was found to react with the pyridine side group of poly (4-vinyl pyridine), forming crosslinked networks which contain cyclic amide structures. The reaction was also observed in the interfacial region of poly(vinyl pyridine) and γ-glycidoxy propyl trimethoxysilane hydrolyzate (γ-GPS) coatings on PET fiber substrates.Poly(2-vinyl pyridine) does not show the same reaction.

  17. Water in Nominally Anhydrous Minerals from Nakhlites and Shergottites

    Science.gov (United States)

    Peslier, Anne H.

    2013-01-01

    Estimating the amount of water in the interior of terrestrial planets has tremendous implications on our understanding of solar nebula evolution, planet formation and geological history, and extraterrestrial volcanism. Mars has been a recent focus of such enquiry with complementary datasets from spacecrafts, rovers and martian meteorite studies. In planetary interiors, water can be dissolved in fluids or melts and hydrous phases, but can also be locked as protons attached to structural oxygen in lattice defects in nominally anhydrous minerals (NAM) such as olivine, pyroxene, or feldspar [1-3]. Measuring water in Martian meteorite NAM is challenging because the minerals are fragile and riddled with fractures from impact processes that makes them break apart during sample processing. Moreover, curing the sample in epoxy causes problems for the two main water analysis techniques, Fourier transform infrared spectrometry (FTIR) and secondary ionization mass spectrometry (SIMS). Measurements to date have resulted in a heated debate on how much water the mantle of Mars contains. SIMS studies of NAM [4], amphiboles [5], and apatites [6-8] from Martian meteorites report finding enough water in these phases to infer that the martian mantle is as hydrous as that of the Earth. On the other hand, a SIMS study of glass in olivine melt inclusions from shergottites concludes that the Martian mantle is much drier [9]. The latter interpretation is also supported by the fact that most martian hydrous minerals generally have the relevant sites filled with Cl and F instead of H [10,11]. As for experimental results, martian basalt compositions can be reproduced using water as well as Cl in the parent melts [12,13]. Here FTIR is used to measure water in martian meteorite minerals in order to constrain the origin of the distribution of water in martian meteorite phases.

  18. The Curious Case of Pyridine - Water

    Science.gov (United States)

    Mackenzie, Becca; Dewberry, Chris; Smith, CJ; Cornelius, Ryan D.; Leopold, Ken

    2016-06-01

    The rotational spectrum of the pyridine\\cdotswater complex has been observed in the 2-18 GHz region using chirped-pulse and cavity Fourier transform microwave spectroscopy. The water is hydrogen bonded to the nitrogen, as expected, but the hydrogen bond is bent, with the oxygen tilted toward either of the ortho hydrogens of the pyridine. This gives rise to a pair of equivalent configurations and the possibility of a tunneling motion involving an in-plane rocking of the water. DFT calculations support this view. Experimentally, a pair of states with severely perturbed rotational structure has been identified and the spectra assigned. Analysis of the perturbations in the a-type (pure rotation) spectra has enabled an accurate determination of the tunneling splitting, which has been confirmed by direct observation of b-type (rotation-tunneling) transitions. A simultaneous fit of the a- and b- type transitions gives the most accurate value of the tunneling splitting. Results for the H2O, D2O, and D-bound HOD complexes will be presented. The tunneling splittings are as follows: H2O-pyridine (10402.9 MHz), HOD-pyridine (12513.4 MHz, determined only from perturbation analysis), and D2O-pyridine (13582.3 MHz). Curiously, the tunneling splitting increases with increased deuteration. Additional small splittings have been observed in some transitions, indicating the possibility of further internal dynamics. This system offers an interesting test case for theoretical treatments of large amplitude motion.

  19. In vitro genotoxicity of pyridine in human lymphocytes.

    Science.gov (United States)

    Emelnsia, Aida D; Rather, Irfan A

    2016-05-01

    This work was carried out to study the genotoxicity of pyridine in vitro on human leucocyte culture. Cyclophosphamide, a well-known carcinogen was used as positive control. The four different concentrations of pyridine and cyclophosphamide showed breaks and pulverization of chromosomes in dose dependent manner. Higher number of pulverization was observed with higher concentration of pyridine (3.25μg/mL). Based on this data, our results confirm that both pyridine and its precursor showed genotoxicity against human lymphocytes.

  20. 40 CFR 721.8750 - Halogenated substituted pyridine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated substituted pyridine. 721... Substances § 721.8750 Halogenated substituted pyridine. (a) Chemical substances and significant new uses... pyridine (PMN P-86-838) is subject to reporting under this section for the significant new uses...

  1. 40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...

  2. 40 CFR 721.8700 - Halogenated alkyl pyridine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated alkyl pyridine. 721.8700... Substances § 721.8700 Halogenated alkyl pyridine. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as halogenated alkyl pyridine (PMN P-83-237)...

  3. Hydrogen Isotopic Systematics of Nominally Anhydrous Phases in Martian Meteorites

    Science.gov (United States)

    Tucker, Kera

    Hydrogen isotope compositions of the martian atmosphere and crustal materials can provide unique insights into the hydrological and geological evolution of Mars. While the present-day deuterium-to-hydrogen ratio (D/H) of the Mars atmosphere is well constrained (~6 times that of terrestrial ocean water), that of its deep silicate interior (specifically, the mantle) is less so. In fact, the hydrogen isotope composition of the primordial martian mantle is of great interest since it has implications for the origin and abundance of water on that planet. Martian meteorites could provide key constraints in this regard, since they crystallized from melts originating from the martian mantle and contain phases that potentially record the evolution of the H 2O content and isotopic composition of the interior of the planet over time. Examined here are the hydrogen isotopic compositions of Nominally Anhydrous Phases (NAPs) in eight martian meteorites (five shergottites and three nakhlites) using Secondary Ion Mass Spectrometry (SIMS). This study presents a total of 113 individual analyses of H2O contents and hydrogen isotopic compositions of NAPs in the shergottites Zagami, Los Angeles, QUE 94201, SaU 005, and Tissint, and the nakhlites Nakhla, Lafayette, and Yamato 000593. The hydrogen isotopic variation between and within meteorites may be due to one or more processes including: interaction with the martian atmosphere, magmatic degassing, subsolidus alteration (including shock), and/or terrestrial contamination. Taking into consideration the effects of these processes, the hydrogen isotope composition of the martian mantle may be similar to that of the Earth. Additionally, this study calculated upper limits on the H2O contents of the shergottite and nakhlite parent melts based on the measured minimum H2O abundances in their maskelynites and pyroxenes, respectively. These calculations, along with some petrogenetic assumptions based on previous studies, were subsequently used

  4. Tetraaquabis(pyridine-κNnickel(II dinitrate

    Directory of Open Access Journals (Sweden)

    Mario Wriedt

    2010-07-01

    Full Text Available In the title compound, [Ni(C5H5N2(H2O4](NO32, the NiII ion is coordinated by two N-bonded pyridine ligands and four water molecules in an octahedral coordination mode. The asymmetric unit consists of one NiII ion located on an inversion center, as well as one pyridine ligand, one nitrate anion and two water molecules in general positions. In the crystal structure, the discrete complex cations and nitrate anions are connected by O—H...O and C—H...O hydrogen bonds.

  5. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-11-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2‧-(2,6-pyridine)-5,5‧-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm‑2 for both anode and cathode sides showed a power density of 76 mW cm‑2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm‑2 with 0.45 mgPt cm‑2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm‑2 in cathode and 0.05 mgPd cm‑2 in anode reached 188 mW cm‑2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs.

  6. Synthesis of 2-substituted pyridines via a regiospecific alkylation, alkynylation, and arylation of pyridine N-oxides.

    Science.gov (United States)

    Andersson, Hans; Almqvist, Fredrik; Olsson, Roger

    2007-03-29

    [structure: see text]. Sequential addition of Grignard reagents to pyridine N-oxides in THF at room temperature followed by treatment with acetic anhydride at 120 degrees C afforded 2-substituted pyridines in good to high yields. Furthermore, by exchanging acetic anhydride for DMF in the second step, 2-substituted pyridine N-oxides were obtained, as intermediates suitable for addition of a second Grignard reagent for the synthesis of 2,6-disubstituted pyridines.

  7. Study on the Stability of DeoxyArbutin in an Anhydrous Emulsion Systemy

    Directory of Open Access Journals (Sweden)

    Chiu-Wen Chen

    2011-09-01

    Full Text Available The skin-whitening agent, deoxyArbutin, is a potent tyrosinase inhibitor that is safer than hydroquinone and arbutin. However, it is thermolabile in aqueous solutions, where it decomposes to hydroquinone. Pharmaceutical and cosmetic emulsions are normally oil-in-water (o/w or water-in-oil (w/o systems; however, emulsions can be formulated with no aqueous phase to produce an anhydrous emulsion system. An anhydrous emulsion system could offer a stable vehicle for compounds that are sensitive to hydrolysis or oxidation. Therefore, to enhance the stability of deoxyArbutin in formulations, we chose the polyol-in-silicone, anhydrous emulsion system as the basic formulation for investigation. The quantity of deoxyArbutin and the accumulation of hydroquinone in both hydrous and anhydrous emulsions at various temperatures were analyzed through an established high performance liquid chromatographic (HPLC method. The results indicated that water increased the decomposition of deoxyArbutin in the formulations and that the polyol-in-silicone, oil-based, anhydrous emulsion system provided a relatively stable surrounding for the deoxyArbutin that delayed its degradation at 25 °C and 45 °C. Moreover, the composition of the inner hydrophilic phase, containing different amounts of glycerin and propylene glycol, affected the stability of deoxyArbutin. Thus, these results will be beneficial when using deoxyArbutin in cosmetics and medicines in the future.

  8. Electrochemical properties of pyridine and dihydropyridine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Elenien, G.; Rieser, J.; Ismail, N.; Wallenfels, K.

    1981-03-01

    The electrochemical oxidation and reduction properties of different dihydropyridines and pyridines have been investigated in non aqueous solvent as benzonitrile and acetonitrile with tetra-n-butylammonium perchlorate as supporting electrolyte at platinum electrodes using DC-voltametry, cycl. voltametry and coulometry. Possible redox-mechanisms are discussed.

  9. Benzene and Pyridine on Silicon (001)

    DEFF Research Database (Denmark)

    Warschkow, Oliver; Bennett, J.M.; Miwa, J. A.

    2017-01-01

    The adsorption chemistry of benzene and pyridine on the silicon (001) surface is characterized by two prominent adsorbate configurations: a precursor structure bonded to a single Si Si dimer and a "tight-bridge" configuration that connects two adjacent dimers. We examine here the performance of 2...

  10. Pretreatment of corn stover using low-moisture anhydrous ammonia (LMAA) process.

    Science.gov (United States)

    Yoo, Chang Geun; Nghiem, Nhuan P; Hicks, Kevin B; Kim, Tae Hyun

    2011-11-01

    A simple pretreatment method using anhydrous ammonia was developed to minimize water and ammonia inputs for cellulosic ethanol production, termed the low moisture anhydrous ammonia (LMAA) pretreatment. In this method, corn stover with 30-70% moisture was contacted with anhydrous ammonia in a reactor under nearly ambient conditions. After the ammoniation step, biomass was subjected to a simple pretreatment step at moderate temperatures (40-120°C) for 48-144 h. Pretreated biomass was saccharified and fermented without an additional washing step. With 3% glucan loading of LMAA-treated corn stover under best treatment conditions (0.1g-ammonia+1.0 g-water per g biomass, 80°C, and 84 h), simultaneous saccharification and cofermentation test resulted in 24.9 g/l (89% of theoretical ethanol yield based on glucan+xylan in corn stover). Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Technical and harmonic analysis of Carl Czerny op. 299 number 34 etude

    Directory of Open Access Journals (Sweden)

    Mehmet Serkan Umuzdas

    2012-11-01

    Full Text Available In this study, the 34th etude of the book Czerny Op. 299 that is one of the commonly employed books in the piano training was analysed in terms of technique and harmony. The etude was examined in terms of its technical features and contributions to technical development. If an etude is analysed before it is played, time and effort can be amanged much more efficiently. In turn, it may contribute to play the etude or work in accordance with its objectives and to produce outcomes. The aims of this study are to make the students aware of the goals and methods of etudes and to provide them with the suggestions for studying. It is suggested that any etude written with the 2/4 rhythm pattern should be played very vividly and energytically. Any etude written in the octave width of 5.5 is made up of 43 scales in two section. The etude is composed of two sections, each with four sentences and two periods. It also involves 43 scales. Of them, 16 scales are in the first section and the remaining 27 scales are in the second section. The etude has very regular system in terms of harmonic continuity and motives. It has a homogenious pattern in terms of the order of the sentences with half-decsion and those with full-decision.

  12. An unrealistic drift in assay on anhydrous basis towards content limit

    Directory of Open Access Journals (Sweden)

    Shivram K

    2009-01-01

    Full Text Available The assay on anhydrous basis is a mathematically derived value from an experimental results of assay and water content tests. The results of assay and water content tests are determined, separately, on as-is basis. The industry-accepted formula for assay on anhydrous basis = (assay on as-is basis×100/(100-%water. Statistically, the two variables involved in accepted formula are assay on as-is basis and water to obtain assay on anhydrous basis. The experimental errors associated with these two variables propagate in assay on anhydrous basis. The error propagates either in constructive or destructive mode. The constructive mode of error propagation is combination of positive error of assay on as-is basis and positive error of water or negative error of assay on as-is basis and negative error of water. The constructive mode of error propagation has more impact on assay on anhydrous basis values and its confidence interval. The destructive mode of error propagation is combination of a positive error of assay on as-is basis and a negative error of water or vice versa. The destructive mode of error propagation has lesser impact on assay on anhydrous basis values and its confidence interval in comparison to the constructive mode of error propagation. In accepted formula said above, the constructive or destructive error propagation causes unrealistic drift of assay on anhydrous basis towards either lower or higher side of content limit of substance. The risk of rejection of pharmaceutical use substance is higher based on assay test results that results are calculated from industry-accepted formula. The purpose of the study is to propose an alternative formula to overcome limitations of accepted formula and justify the propagation of errors in realistic way. We have given three examples of pharmaceutical use substances to emphasise the above proposition. The proposed formula for assay on anhydrous basis= (assay on as-is basis×F/(F-%water in which F is

  13. PENULISAN ETUDE-ETUDE MUSIK TALEMPONG UNGGAN (Sebuah Usaha Pembelajaran Musik Tradisi Berbasis Literatur

    Directory of Open Access Journals (Sweden)

    Asri MK

    2014-12-01

    Full Text Available “Talempong unggan”, a traditional music from Minangkabau community particularly in Unggan, Sumpur Kudus, Sijunjung Regency, West Sumatera Indonesia is classified into genre of “talempong duduak” (rea. Due to its special musical concept and the playing technics, this traditional music is selected as a practising course in the Karawitan Department of Indonesian Institute of Art (ISI Padang Panjang since 1993 till now. In a system of class learning with many students, Talempong Unggan definitely needs supporting methods and learning technics suitable for the course where the students can reach their maximum skills. All the melody of “talempong unggan” that has been made as a material of practice is transcribed to the system of numeric notation and rhythm motive of “gendang” and “aguang” which is written into signs and special notation. All of qualitative data is formulated into finding methods, technics and etude of learning ensamble of Talempong Unggan the traditional music that learned in Karawitan Department of ISI Padang Panjang. Key words: Talempong Unggan, Methods, Technics, Etude

  14. Influence of amorphous content on compaction behaviour of anhydrous alpha-lactose.

    Science.gov (United States)

    Ziffels, S; Steckel, H

    2010-03-15

    Modified lactoses are widely used as filler-binders in direct compression of tablets. Until today, little about the compaction behaviour of anhydrous alpha-lactose is known. In this study, a new method to prepare anhydrous alpha-lactose from alpha-lactose monohydrate by desiccation with heated ethanol was evaluated and the influence of amorphous content in the lactose powder prior to modification on powder properties, compaction behaviour and storage stability was determined. The modification process led to anhydrous alpha-lactose with decreased bulk and tapped density, increased flow rate and significantly higher specific surface area. Due to the higher specific surface area, the compaction behaviour of the anhydrous alpha-lactose was found to be significantly better than the compaction behaviour of powder blends consisting of alpha-lactose monohydrate and amorphous lactose. An influence of the amorphous content prior to modification could be observed only at higher compaction forces. In general, tablets of modified powders needed longer time to disintegrate directly after compression. However, the storage stability of modified tablets was found to be better compared to the amorphous-crystalline tablets which were influenced by storage conditions, initial crushing strength as well as amorphous content due to the re-crystallization of amorphous lactose during storage. 2009 Elsevier B.V. All rights reserved.

  15. Melt-processed anhydrous proton exchange membranes for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Mokrini, A.; Siu, A.; Diaz, G.; Crites, C.; Robitaille, L. [National Research Council of Canada, Boucherville, PQ (Canada). Industrial Materials Inst.

    2009-07-01

    The current benchmark materials for proton exchange membrane (PEM) fuel cells are perfluorosulfonic acid resins (PFSA) because of their excellent stability and proton conductivity of 0.1 s/cm at 80 degrees C when fully humidified. However their performance decreases significantly at higher temperatures and low humidity. This paper presented the properties of nanocomposite PEMs incorporating a series of anhydrous charge carriers that are viable candidates for making water-free membranes that can operate at temperatures above 120 degrees C. However, the volatility or leaching of these anhydrous charge carriers could prevent them from being successfully used in open electrochemical systems. Therefore, in this study, the anhydrous charge carriers were immobilized on inorganic nanoparticles and incorporated into PEMs formulations. Nanoparticles with diameters ranging from 50-200 nm were synthesized via a sol-gel process and the desired anhydrous charge carriers immobilized on their surfaces. Nanocomposite PEMs were prepared using melt-processing technologies, by blending the grafted nanoparticles and fluorinated polymers such as poly (vinylidene fluoride) (PVDF) and ionomers such as Nafion. This paper presented the properties of the PEMs developed as a function of nanoparticles size and content, as well as the proton conductivity at controlled temperature and RH.

  16. Corn yield and nitrate loss in subsurface drainage affected by timing of anhydrous ammonia application

    Science.gov (United States)

    Surprisingly little research has examined the corn yield, N use efficiency, and water quality implications of N fertilizer timing. We applied anhydrous ammonia either in the fall after harvest (F) at 196 kg ha-1, or in the spring before planting (PP) or as an early sidedress (SD) at rates of 168 kg ...

  17. Analytical reagents based on pyridine aldehydes

    Energy Technology Data Exchange (ETDEWEB)

    Lejtis, L.Ya.; Skolmejstere, R.A.; Rubina, K.I.; Yansone, D.P.; Shimanskaya, N.V. (AN Latvijskoj SSR, Riga. Inst. Organicheskogo Sinteza)

    1985-03-01

    The papers published in 1950 through 1983 on the use of pyriodine aldehydes and their derivatives as analytical reagents for determining inorganic and organic substances are considered. To determining cations of transition metals, pyridine aldehydes, such as oximethanephosphonic acid, oximes azomethines, hydrazones, semicarbazones, are also applied. The complexing reactions of transition metal ions with pyrimine aldehydes and the structure of complexes obtained are considered. Spectrophotometric characteristics of complexes of Cd, V, Rv and other metals with pyridine aldehydes are given. Optimum conditions are shown for the formation of complexes as well as their stability, concentration ranges in which the beer law is observed, sensitivity and errors of spectrophotometric determination of the ions are in question.

  18. SYNTHESIS AND CHARACTERIZATION OF HETEROAROMATIC POLYMERS CONTAINING PYRIDINE MOIETIES

    Institute of Scientific and Technical Information of China (English)

    LI Yanfeng; WANG Xiaolong; ZHANG Shujiang

    2006-01-01

    The progress on the molecular design, synthesis and characterizations of some kinds of pyridine-containing heteroaromatic polymers in main chain were reviewed in this paper, they would include polyimides (PIs), polypyrrolones (PPYs), poly(pyrrolone-imide)s (PPIs), and poly(pyrrolone-benzimidazone)s (PPBs) containing pyrldine moieties. The pyridine-containing polymers reported all exhibit good processability, excellent thermal properties and mechanical properties. However, the contribution of pyridine ring to polymers properties is still need to research further, the heteroarornatic polymers containing pyridine moieties have focused by more and more researchers.

  19. 40 CFR 721.10034 - Substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridine coupled with... Specific Chemical Substances § 721.10034 Substituted pyridine coupled with diazotized substituted... as substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...

  20. Self-Assembled Pyridine-Dipyrrolate Cages.

    Science.gov (United States)

    Zhang, Huacheng; Lee, Juhoon; Lammer, Aaron D; Chi, Xiaodong; Brewster, James T; Lynch, Vincent M; Li, Hao; Zhang, Zhan; Sessler, Jonathan L

    2016-04-06

    An inherently nonlinear pyridine dipyrrolate ligand, namely 2,6-bis(3,4-diethyl-5-carboxy-1H-pyrrol-2yl)pyridine (compound 1), is able to distinguish between different zinc(II) cation sources, namely Zn(acac)2 and Zn(OAc)2, respectively. This differentiation is manifest both in terms of the observed fluorescent behavior in mixed organic media and the reaction chemistry. Treatment of 1 with Zn(acac)2 gives rise to a cage dimer, cage-1, wherein two molecules of compound 1 act as double bridging units to connect two individual cage subunits. As inferred from X-ray crystallographic studies, this cage system consists of discrete zinc dimers with hydroxide bridges that, with the assistance of bound DMF solvent molecules, serve to fix the geometry and orientation of the pyridine dipyrrolate building blocks. When a different zinc source, Zn(OAc)2, is used to carry out an ostensibly similar complexation reaction with compound 1, an acetate-bridged 1D abacus-like cage polymer is obtained as inferred from X-ray diffraction analysis. This extended solid state structure, cage-2, contains individual zinc dimer cage submits and appears stabilized by solvent molecules (DMF) and the counteranion (acetate). Rod-like assemblies are also observed by DLS and SEM. This construct, in contrast to cage-1, proved fluorescent in mixed organic media. The structure of the ligand itself (i.e., in the absence of Zn(II)) was confirmed by X-ray crystallographic analysis and was found to assemble into a supramolecular polymer. Conversion to a dimer form was seen upon the addition of TBAOAc. On the basis of the metric parameters, the structures seen in the solid state are stabilized via hydrogen bonding interactions involving solvent molecules.

  1. 2-[(Pyridin-3-ylaminomethyl]phenol

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2011-12-01

    Full Text Available In the title compound, C12H12N2O, the aromatic rings at either ends of the –CH2–NH– link are twisted by 68.79 (7°. In the crystal, the hydroxy substituent is a hydrogen-bond donor to the N atom of the pyridine ring of an adjacent molecule, and the hydrogen bond generates a chain along the b axis; it is also a hydrogen-bond acceptor to the amino group of another adjacent molecule. The two hydrogen bonds lead to the formation of a layer structure.

  2. Electroenzymatic Reactions With Oxygen on Laccase-Modified Electrodes in Anhydrous (Pure) Organic Solvent

    DEFF Research Database (Denmark)

    Yarapolov, A.; Shleev, S.; Zaitseva, E.

    2007-01-01

    The electroenzymatic reactions of Trametes hirsuta laccase in the pure organic solvent dimethyl sulfoxide (DMSO) have been investigated within the framework for potential use as a catalytic reaction scheme for oxygen reduction. The bioelectrochemical characteristics of laccase were investigated...... in two different ways: (i) by studying the electroreduction of oxygen in anhydrous DMSO via a direct electron transfer mechanism without proton donors and (ii) by doing the same experiments in the presence of laccase substrates, which display in pure organic solvents both the properties of electron...... donors as well as the properties of weak acids. The results obtained with laccase in anhydrous DMSO were compared with those obtained previously in aqueous buffer. It was shown that in the absence of proton donors under oxygenated conditions, formation of superoxide anion radicals is prevented at bare...

  3. Method of Preparation for High-Purity Nanocrystalline Anhydrous Cesium Perrhenate

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-03-01

    Full Text Available This paper is devoted to the preparation of high-purity anhydrous nanocrystalline cesium perrhenate, which is applied in catalyst preparation. It was found that anhydrous cesium perrhenate with a crystal size <45 nm can be obtained using cesium ion sorption and elution using aqueous solutions of perrhenic acid with subsequent crystallisation, purification, and drying. The following composition of the as-obtained product was reported: 34.7% Cs; 48.6% Re and <2 ppm Bi; <3 ppm Zn; <2 ppm As; <10 ppm Ni; < 3 ppm Mg; <5 ppm Cu; <5 ppm Mo; <5 ppm Pb; <10 ppm K; <2 ppm Na; <5 ppm Ca; <3 ppm Fe.

  4. Ab initio and DFT studies of the structure and vibrational spectra of anhydrous caffeine.

    Science.gov (United States)

    Srivastava, Santosh K; Singh, Vipin B

    2013-11-01

    Vibrational spectra and molecular structure of anhydrous caffeine have been systematically investigated by second order Moller-Plesset (MP2) perturbation theory and density functional theory (DFT) calculations. Vibrational assignments have been made and many previous ambiguous assignments in IR and Raman spectra are amended. The calculated DFT frequencies and intensities at B3LYP/6-311++G(2d,2p) level, were found to be in better agreement with the experimental values. It was found that DFT with B3LYP functional predicts harmonic vibrational wave numbers more close to experimentally observed value when it was performed on MP2 optimized geometry rather than DFT geometry. The calculated TD-DFT vertical excitation electronic energies of the valence excited states of anhydrous caffeine are found to be in consonance to the experimental absorption peaks.

  5. Structural basis for the transformation pathways of the sodium naproxen anhydrate-hydrate system

    DEFF Research Database (Denmark)

    Bond, Andrew; Cornett, Claus; Larsen, Flemming Hofmann

    2014-01-01

    Crystal structures are presented for two dihydrate polymorphs (DH-I and DH-II) of the non-steroidal anti-inflammatory drug sodium (S)-naproxen. The structure of DH-I is determined from twinned single crystals obtained by solution crystallization. DH-II is obtained by solid-state routes, and its...... structure is derived using powder X-ray diffraction, solid-state (13)C and (23)Na MAS NMR, and molecular modelling. The validity of both structures is supported by dispersion-corrected density functional theory (DFT-D) calculations. The structures of DH-I and DH-II, and in particular their relationships...... to the monohydrate (MH) and anhydrate (AH) structures, provide a basis to rationalize the observed transformation pathways in the sodium (S)-naproxen anhydrate-hydrate system. All structures contain Na(+)/carboxylate/H2O sections, alternating with sections containing the naproxen molecules. The structure of DH...

  6. Ab initio and DFT studies of the structure and vibrational spectra of anhydrous caffeine

    Science.gov (United States)

    Srivastava, Santosh K.; Singh, Vipin B.

    2013-11-01

    Vibrational spectra and molecular structure of anhydrous caffeine have been systematically investigated by second order Moller-Plesset (MP2) perturbation theory and density functional theory (DFT) calculations. Vibrational assignments have been made and many previous ambiguous assignments in IR and Raman spectra are amended. The calculated DFT frequencies and intensities at B3LYP/6-311++G(2d,2p) level, were found to be in better agreement with the experimental values. It was found that DFT with B3LYP functional predicts harmonic vibrational wave numbers more close to experimentally observed value when it was performed on MP2 optimized geometry rather than DFT geometry. The calculated TD-DFT vertical excitation electronic energies of the valence excited states of anhydrous caffeine are found to be in consonance to the experimental absorption peaks.

  7. Neutron diffraction analysis of residual stresses near unannealed welds in anhydrous ammonia nurse tanks.

    Science.gov (United States)

    Becker, A T; Chumbley, L S; Goettee, D; Russell, A M

    2014-01-01

    Neutron diffraction analysis was employed to measure residual stresses near welds in used anhydrous ammonia nurse tanks. Tensile residual stresses contribute to stress corrosion cracking of nurse tanks, which can cause tanks to release toxic ammonia vapor. The analysis showed that tensile residual stresses were present in the tanks measured, and the magnitudes of these stresses approached the yield strength of the steel. Implications for agricultural safety and health are discussed.

  8. Mössbauer study on the gamma radiolysis of anhydrous cesium tris (oxalato) ferrate(III)

    Science.gov (United States)

    Ladriere, J.; Senterre, V.; Apers, D.

    1992-04-01

    The final product of the gamma radiolysis of anhydrous cesium tris(oxalato) ferrate(III) has been identified by Mössbauer spectroscopy as Cs2Fe(ox)2. The radiolytic decomposition proceeds as a first-order process due to the original compound depletion and to the radiolytic stability of the ferrous compound. Lamb-Mössbauer factors measurements indicate that the recoilless fractions of the iron species are practically unaffected by the radiolysis.

  9. THE PRODUCTION OF PURE ABSOLUTE ALCOHOL WITH CALCIUM CARBIDE AND ANHYDROUS COPPER SULPHATE.

    Science.gov (United States)

    Lyons, R E; Smith, L T

    1925-09-01

    (1) The above is recommended as an economical, convenient and quick method for producing absolute alcohol on a laboratory scale. If the distillation is executed with free flame, excessive or careless heating must be avoided near the end of the operation because of the copper acetylide in the residue. (2) Calcium carbide is recommended over potassium permanganate or anhydrous copper sulphate as a qualitative reagent in detecting traces of water in alcohol.

  10. Nuclear study of Melusine; Etude nucleaire de Melusine

    Energy Technology Data Exchange (ETDEWEB)

    Cherot, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    In this report are reviewed - with respect to starting of experiments - the main nuclear characteristics of a 20 per cent enriched uranium lattice, with light water as moderator and reflector. The reactor is to operate at 1 MW. 1) Study of various critical masses. 2) Control. Effectiveness of cadmium. Control rods and of a stainless steel regulating rod. 3) Study of the effect on reactivity of disturbances in the core center. 4) Study of xenon and samarium poisoning. 5) Temperature factor. 6) Heat exchanges in a fuel element. (author) [French] On etudie, dans ce rapport, les principales proprietes nucleaires d'un reseau a uranium enrichi (20 pour cent), dont le moderateur et le reflecteur sont l'eau legere en vue des experiences de demarrage. Ce reacteur devra fonctionner a 1 MW. 1) Etude de diverses masses critiques. 2) Controle. Efficacite des barres de controle en cadmium et d'une barre de reglage en acier inoxydable. 3) Etude de l'effet sur la reactivite de perturbation au centre du coeur. 4) Etude de l'empoisonnement xenon et samarium. 5) Coefficient de temperature. 6) Echanges thermiques dans un element. (auteur)

  11. Preparation of anhydrous magnesium chloride in a gas-solid reaction with ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    Zhou Ningbo; Chen Baizhen; He Xinkuai; Li Yibing

    2006-01-01

    Dehydrated ammonium carnallite was synthesized with bischofite from salt lake and ammonium chloride solution in a 1:1 molar ratio of MgCl2:NH4Cl,dehydrated at 160℃ for about 4 h.The yield was above 85%.The product was then mixed with solid-state ammonium chloride with a 1:4 mass ratio for the further dehydration at 410℃.The decomposition of NH4Cl made a pressure of NH3 at 30.5 kPa to prevent the hydrolysis of ammonium carnallite.The anhydration of magnesium chloride was achieved at 700℃.The results showed that anhydrous magnesium chloride contains magnesium oxide in an amount that was less than 0.1% by weight.XRD pattern and SEM micrograph showed a good dispersion of ammonium carnallite and anhydrous magnesium chloride crystals with well-distributed big grains,just enough to meet the need for the production of magnesium metal in the electrolysis process.

  12. Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ning-bo; CHEN Bai-zhen; HE Xin-kuai; LI Yi-bing

    2006-01-01

    Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuwas synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃ for 4 h. Ammonium carnallite reacted with ammonia at 240℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃ into anhydrous magnesium chloride containing only 0.1% (mass fraction) of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1:4 at high temperature and with the differential pressure of HN3 above 30.5 kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃ into anhydrous magnesium chloride with only 0. 087% (mass fraction) of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn't mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.

  13. Anhydrous proton conducting membranes for PEM fuel cells based on Nafion/Azole composites

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Unal; Ata, Ali [Gebze Institute of Technology, Materials Science and Engineering, Gebze, Kocaeli (Turkey); Uenueguer Celik, Sevim; Bozkurt, Ayhan [Department of Chemistry, Fatih University, 34500, Buyukcekmece, Istanbul (Turkey)

    2008-06-15

    Proton conducting membranes are the most crucial part of energy generating electrochemical systems such as polymer electrolyte membrane fuel cells (PEMFCs). In this work, Nafion based proton conducting anhydrous composite membranes were prepared via two different approaches. In the first, commercial Nafion115 and Nafion112 were swelled in the concentrated solution of azoles such as 1H-1,2,4-triazole (Tri), 3-amino-1,2,4-triazole (ATri) and 5-aminotetrazole (ATet) as heterocyclic protogenic solvents. In the second, the proton conducting films were cast from the Nafion/Azole solutions. The partial protonation of azoles in the anhydrous membranes were studied by Fourier transform infrared (FT-IR) spectroscopy. Thermal properties were investigated via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA results showed that Nafion/ATri and Nafion/ATet electrolytes are thermally stable at least up to 200 C. Methanol permeability measurements showed that the composite membranes have lower methanol permeability compared to Nafion112. Nafion115/ATri system has better conductivity at 180 C, exceeding 10{sup -3} S/cm compared to other Nafion/heterocycle systems under anhydrous conditions. (author)

  14. Use of lycopene as a natural antioxidant in extending the shelf-life of anhydrous cow milk fat.

    Science.gov (United States)

    Siwach, Ruby; Tokas, Jayanti; Seth, Raman

    2016-05-15

    Oxidative rancidity in anhydrous cow milk fat leads to reduction in its shelf life. Use of synthetic antioxidants is prevalent in dairy industry to prevent the development of rancidity. Keeping in view the increasing demand for natural additives, the present study was carried out to explore the potential of lycopene as a natural antioxidant in anhydrous cow milk fat. Lycopene at five different levels (30, 60, 90, 120 and 150 ppm) and butylated hydroxyl anisole (200 ppm), were incorporated in anhydrous cow milk fat. Potential of lycopene extract to enhance the shelf life of anhydrous cow milk fat was evaluated by measuring Free Fatty Acids, peroxide value, Thiobarbituric Acid value and color value during 12 months of storage at ambient conditions (30°C). Lycopene significantly (pLycopene containing samples scored significantly higher in terms of sensory attributes as compared to control.

  15. Preparation of nucleoside-pyridine hybrids and pyridine attached acylureas from an unexpected uracil ring-opening and pyridine ring-forming sequence

    Institute of Scientific and Technical Information of China (English)

    Xue Sen Fan; Xia Wang; Xin Ying Zhang; Dong Feng; Ying Ying Qu

    2009-01-01

    Novel pyrimidine nucleoside-3,5-dicyanopyridine hybrids (4) or pyridine attached acylureas (5) were selectively and efficiently prepared from the reaction of 2'-deoxyuridin-5-yl-methylene malonortitrile (1), malononitrile (2) and thiophenol (3) or from an unexpected uracil ring-opening and pyridine ring-forming sequence via the reaction of 1 and 3. It is the first time such a sequence has ever been reported.

  16. Synthesis of Chiral Macrocyclic or Linear Pyridine Carboxamides from Pyridine-2,6-dicarbonyl Dichloride as Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Abd El-Galil E Amr

    2010-09-01

    Full Text Available A series of chiral linear and macrocyclic bridged pyridines has been prepared starting from pyridine-2,6-dicarbonyl dichloride (2. The coupling of 1 with D-alanyl methyl ester gave 2,6-bis-D-alanyl pyridine methyl ester (3. Hydrazinolysis of 3 with hydrazine hydrate afforded bis-hydrazide 4. The latter was reacted with thiophene-2-carbaldehyde, phthalic anhydride or cyclohexanone to afford bis-carboxamide pyridine derivatives 5-7, respectively. Compound 4 was coupled with p-methoxy- or p-nitroaceto-phenone to yield compounds 8 and 9. In addition, 4 was reacted with 1,2,4,5-benzenetetra-carboxylic acid dianhydride or 1,4,5,8-naphthalenetetracarboxylic acid dianhydride to afford the macrocyclic octacarboxaamide pyridines 10 and 11. The detailed synthesis, spectroscopic data and antimicrobial screening for the synthesized compounds are reported.

  17. Van der Waals Interactions in Pyridine and Pyridine-like Molecular Crystals: An ab initio Molecular Dynamics Study

    Science.gov (United States)

    Ko, Hsin-Yu; Distasio, Robert A., Jr.; Santra, Biswajit; Car, Roberto

    2014-03-01

    Pyridine has recently been investigated as a potentially effective material for use in artificial light harvesting.In this work, we propose the use of ab initio molecular dynamics (AIMD) to gain valuable physical insight into the artificial photosynthetic processes occurring in condensed-phase pyridine, the study of which has been limited to semi-empirical force fields to date.For this purpose, we introduce an accurate and efficient AIMD method, based on density functional theory (DFT) and a self-consistent pairwise description of van der Waals (vdW) interactions, for use in finite temperature and pressure (NPT) simulations on pyridine and several pyridine-like molecular crystals (PLMCs). Utilizing this approach, we demonstrate that vdW forces play a crucial role in the theoretical prediction of the structure and density of pyridine and PLMCs, and therefore must be accounted for in studies of these potential alternative energy materials. DOE: DE-SC0008626, NSF: DMS-1065894.

  18. Lipase-catalyzed process in an anhydrous medium with enzyme reutilization to produce biodiesel with low acid value.

    Science.gov (United States)

    Azócar, Laura; Ciudad, Gustavo; Heipieper, Hermann J; Muñoz, Robinson; Navia, Rodrigo

    2011-12-01

    One major problem in the lipase-catalyzed production of biodiesel or fatty acid methyl esters (FAME) is the high acidity of the product, mainly caused by water presence, which produces parallel hydrolysis and esterification reactions instead of transesterification to FAME. Therefore, the use of reaction medium in absence of water (anhydrous medium) was investigated in a lipase-catalyzed process to improve FAME yield and final product quality. FAME production catalyzed by Novozym 435 was carried out using waste frying oil (WFO) as raw material, methanol as acyl acceptor, and 3Å molecular sieves to extract the water. The anhydrous conditions allowed the esterification of free fatty acids (FFA) from feedstock at the initial reaction time. However, after the initial esterification process, water absence avoided the consecutives reactions of hydrolysis and esterification, producing FAME mainly by transesterification. Using this anhydrous medium, a decreasing in both the acid value and the diglycerides content in the product were observed, simultaneously improving FAME yield. Enzyme reuse in the anhydrous medium was also studied. The use of the moderate polar solvent tert-butanol as a co-solvent led to a stable catalysis using Novozym 435 even after 17 successive cycles of FAME production under anhydrous conditions. These results indicate that a lipase-catalyzed process in an anhydrous medium coupled with enzyme reuse would be suitable for biodiesel production, promoting the use of oils of different origin as raw materials.

  19. Pyridine-grafted chitosan derivative as an antifungal agent.

    Science.gov (United States)

    Jia, Ruixiu; Duan, Yunfei; Fang, Qiang; Wang, Xiangyang; Huang, Jianying

    2016-04-01

    Pyridine moieties were introduced into chitosan by nucleophilic substitution to afford N-(1-carboxybutyl-4-pyridinium) chitosan chloride (pyridine chitosan). The resulting chitosan derivative was well characterized, and its antifungal activity was examined, based on the inhibition of mycelial growth and spore germination. The results indicated that pyridine chitosan exhibited enhanced antifungal activity by comparison with pristine chitosan. The values of the minimum inhibitory concentration and the minimal fungicidal concentration of pyridine chitosan against Fulvia fulva were 0.13 mg/ml and 1 mg/ml, respectively, while the corresponding values against Botrytis cinerea were 0.13 mg/ml and 4 mg/ml, respectively. Severe morphological changes of pyridine chitosan-treated B. cinerea were observed, indicative that pyridine chitosan could damage and deform the structure of fungal hyphae and subsequently inhibit strain growth. Non-toxicity of pyridine chitosan was demonstrated by an acute toxicity study. These results are beneficial for assessing the potential utilization of this chitosan derivative and for exploring new functional antifungal agents with chitosan in the food industry.

  20. Synthesis and Structure of Bis-(o-vanillin)di-pyridine Nickel(Ⅱ)-pyridine Dihydrate

    Institute of Scientific and Technical Information of China (English)

    孙命; 王瑾玲; 段月琴; 缪方明; 翁林红; 冷雪冰

    2001-01-01

    The structure of the complex bis-(o-vanillin)di-pyridine nickel(Ⅱ)([ Ni X-ray analysis.The crystal data are as follows: Monoclinic,P21/n,a=12.273(1),b=17.4700.674mm-1,F(000)=1328,final R=0.0428,Rw=0.1228 for 4528 observable reflections with I≥2σ(Ⅰ).The Nickel(Ⅱ)atom in the complex has a slightly distorted octahedral coordination geometr y and is six-coordinated by four O atoms from two O-Vanillin ligands and two N atoms from two pyridines.In the crystal,the Ni(Ⅱ)-complex and water molecules are linked through a network of hydrogen bonds.

  1. The mechanism of pyridine hydrogenolysis on molybdenum-containing catalysts : II. Hydrogenation of pyridine to piperidine

    NARCIS (Netherlands)

    Sonnemans, J.; Berg, van den G.H.; Mars, P.

    1973-01-01

    The kinetics of pyridine hydrogenation was studied at high hydrogen pressures on a Mo-Al oxide and a Co-Mo-Al oxide catalyst. The rate equation was found to be r = kPpyrPH2n/Ppyro, in which n is 1.5 at 300 and 375 °C and 1.0 at 250 °C. This rate equation can be derived assuming strong adsorption of

  2. PYRIDINATION OF POLY(VINYL CHLORIDE) via A HOMOLYTIC PATHWAY

    Institute of Scientific and Technical Information of China (English)

    Sa(a)d Moulay; Zakia Zeffouni

    2007-01-01

    PVC was subjected to a chemical modification aiming at replacing the chlorine atoms by pyridine groups via a homolytic route. Pyridine groups were peculiarly affixed to the PVC matrix via a carbon-carbon bond rather than a carbonnitrogen one. PVC was first iodinated using the Conant-Finkelstein reaction, followed by the application of the homolytic conditions of Minisci to generate pyridinated PVC with a varying degree of substitution. The extent of substitution was not high; the reaction on 30% iodinated PVC afforded a degree of modification no greater than 3%.

  3. Transition-metal-free hydration of nitriles using potassium tert-butoxide under anhydrous conditions.

    Science.gov (United States)

    Midya, Ganesh Chandra; Kapat, Ajoy; Maiti, Subhadip; Dash, Jyotirmayee

    2015-04-17

    Potassium tert-butoxide acts as a nucleophilic oxygen source during the hydration of nitriles to give the corresponding amides under anhydrous conditions. The reaction proceeds smoothly for a broad range of substrates under mild conditions, providing an efficient and economically affordable synthetic route to the amides in excellent yields. This protocol does not need any transition-metal catalyst or any special experimental setup and is easily scalable to bulk scale synthesis. A single-electron-transfer radical mechanism as well as an ionic mechanism have been proposed for the hydration process.

  4. The Cl Isotope Composition of the Moon as evidence for an Anhydrous Mantle (Invited)

    Science.gov (United States)

    Sharp, Z. D.; Shearer, C., Jr.; McKeegan, K. D.; Barnes, J.; Wang, Y.

    2010-12-01

    The chlorine isotope composition of primitive terrestrial basalts and carbonaceous chondrites cover a narrow range centered around 0‰ with a total variation of ± 0.5‰. In contrast, the chlorine isotope composition of bulk samples and in situ ion microprobe analyses of lunar basalts and glasses cover a range of 25‰. Three possibilities were considered to explain the large spread: 1) initial isotopic heterogeneities, 2) devolatilization from solar wind/micrometeorite bombardment, 3) degassing under anhydrous conditions. The first of these possibilities is rejected because the Moon went through an magma ocean stage which would have homogenized any isotopic heterogeneities. To examine surface effects, we chose samples that have extremely different degrees of surface exposure. We find no correlation between the Cl isotope composition and surface exposure. We also conducted a laboratory experiment in which a thin film of NaCl was bombarded with a proton source for 24 hours with no change in Cl isotope composition. The third possibility is that the fractionation is explained by the anhydrous character of the Moon. On Earth, the volatiling Cl species is HCl. HCl is known to preferentially incorporate 37Cl relative to 35Cl due to the high bond strength of the molecule. This is offset by the higher translational velocity of H35Cl, so that overall, there is very little Cl isotope fractionation during degassing. We propose that lunar basalts were anhydrous and the volatile Cl species were metal chlorides, such as ZnCl2, NaCl, FeCl2, etc. The bond strength of metal chlorides and Cl dissolved in a basalt are similar, so that fractionation is caused mainly by volatilization, with the light isotopologue preferentially lost to the vapor phase. This idea is supported by the consistent lower Cl isotope ratios of water soluble salt fraction (~10 ‰ lower) and the lowest lunar Cl isotope values close to those of bulk Earth. The H content of lunar magmas must have been lower

  5. Homocoupling of Aryl Bromides Catalyzed by Nickel Chloride in Pyridine

    Institute of Scientific and Technical Information of China (English)

    TAO, Xiao-Chun; ZHOU, Wei; ZHANG, Yue-Ping; DAI, Chun-ya; SHEN, Dong; HUANG, Mei

    2006-01-01

    Pyridine was used as a solvent for homocoupling of aryl bromides catalyzed by nickel chloride/triarylphosphine in the presence of zinc and recycled easily. Triphenylphosphine was the best ligand for nickel in this coupling reaction.

  6. Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

    National Research Council Canada - National Science Library

    Islam, Mohammad T; Rodríguez-Hornedo, Naír; Ciotti, Susan; Ackermann, Chrisita

    2004-01-01

    .... Comparisons of the spectra of Carbopol dispersions in aqueous, anhydrous, and hydroalcoholic systems, performed for the first time, show Carbopol-neutralizer and Carbopol-surfactant interactions vary...

  7. Anhydrous proton conducting materials based on sulfonated dimethylphenethylchlorosilane grafted mesoporous silica/ionic liquid composite.

    Science.gov (United States)

    Amiinu, Ibrahim Saana; Liang, Xinmiao; Tu, Zhengkai; Zhang, Haining; Feng, Jiwen; Wan, Zhongmin; Pan, Mu

    2013-11-27

    Efficient membrane proton conductivity at elevated temperatures (>100 °C) and reduced humidification conditions is a critical issue hindering fuel cell commercialization. Herein, proton conducting materials consisting of high surface area acid catalyzed mesoporous silica functionalized with sulfonated dimethylphenethylchlorosilane was investigated under anhydrous conditions. The organic moiety covalently bonded to the silica substrate via active hydroxyl groups on the silica pore surface. The structure and dynamic phases of the attached organic molecule were characterized and qualitatively determined by XRD, TEM, FT-IR, and solid state NMR. The amount of grafted organic molecules was estimated to be 2.45 μmol m(-2) by carbon elemental analysis. The so-formed composite materials showed adequate thermal stability up to 300 °C as determined by TGA. Under anhydrous conditions, ionic conductivity of the composite material upon ionic liquid impregnation reaches a peak value of 1.14 × 10(-2) S cm(-1) at 160 °C associated with the activation energy of 9.24 kJ mol(-1) for proton transport.

  8. Anhydrous ethanol production in sugar mills; Produccion de etanol anhidro en ingenios azucareros

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez Poy, Manuel. E-mail:poymanuel@prodigy.net.mx

    2007-04-15

    The anhydrous ethanol production is recent and limited, because the disadvantage of the renewable energies is the economic impossibility of the projects. Nevertheless, there are aspects to consider to achieve the anhydrous ethanol production, among which are: the cost of the raw material, the self-sufficiency of energy from the sugar cane bagasse without the need of oil burning, the larger size of the distilleries, incorporation of the Cogeneration with delivery of electricity to the public network in the sugar mill facilities, the introduction of the biotechnology to improve the processes of fermentation and subsidies to agriculture. [Spanish] La produccion de etanol anhidro es reciente y limitada, debido a que la desventaja de las energias renovables es la inviabilidad economica de los proyectos. Sin embargo hay aspectos a considerar para lograr la produccion de etanol anhidro, entre los cuales estan: el costo de la materia prima, la autosuficiencia energetica a partir del bagazo de la cana sin necesidad de petroleo, mayor tamano de las destilerias, incorporacion de la Cogeneracion con entrega de electricidad a la red publica en el ingenio, la introduccion de la biotecnologia para mejorar los procesos de fermentacion y subsidios a la agricultura.

  9. Structural and Theoretical Investigation of Anhydrous 3,4,5-Triacetoxybenzoic Acid.

    Directory of Open Access Journals (Sweden)

    Paulo S Carvalho

    Full Text Available A comprehensive investigation of anhydrous form of 3,4,5-Triacetoxybenzoic acid (TABA is reported. Single crystal X-ray diffraction, Thermal analysis, Fourier Transform Infrared spectroscopy (FTIR and DFT calculations were applied for TABA characterization. This anhydrous phase crystallizes in the triclinic [Formula: see text] space group (Z' = 1 and its packing shows a supramolecular motif in a classical [Formula: see text] ring formed by acid-acid groups association. The phase stability is accounted in terms of supramolecular architecture and its thermal behaviour. Conformation search at B3LYP/6-311++G(2d,p level of theory shows the existence of three stable conformers and the most stable conformation was found experimentally. The reactivity of TABA was investigated using the molecular orbital theory and molecular electrostatic potential. The calculation results were used to simulate the infrared spectrum. There is a good agreement between calculated and experimental IR spectrum, which allowed the assignment of the normal vibrational modes.

  10. A kinetic study of non-isothermal decomposition process of anhydrous nickel nitrate under air atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Jankovic, B., E-mail: bojanjan@ffh.bg.ac.r [Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, P. O. Box 137, 11001 Belgrade (Serbia); Mentus, S. [Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, P. O. Box 137, 11001 Belgrade (Serbia); Jelic, D. [Faculty of Medicine, University of Banja Luka, 78000 Banja Luka (Bosnia and Herzegowina)

    2009-08-01

    The non-isothermal decomposition process of anhydrous nickel nitrate under air atmosphere was investigated. The kinetic analysis of decomposition process was performed using Friedman (FR), Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) isoconversional methods. The kinetic model was determined by the Malek's method. The composite differential method I was used for checking the established reaction model. It was found that the value of E{sub a} calculated by composite differential method (E{sub a}=147.1 kJ mol{sup -1}) represents the medium value between the values of the apparent activation energy calculated by FR (E{sub a,FR}=152.8 kJ mol{sup -1}) and FWO (E{sub a,FWO}=143.1 kJ mol{sup -1}) methods. Using two special functions (y(alpha) and z(alpha)), it was found that the two-parameter autocatalytic model (Sestak-Berggren (SB) kinetic model) with kinetic exponents M=0.23 and N=1.14 is the most adequate one to describe the decomposition kinetics of the studied system at various heating rates. The obtained non-isothermal differential conversion curves from the experimental data show the results being accordant with those theoretically calculated. It was concluded that the SB kinetic model can be used for a quantitative description of non-isothermal decomposition process of anhydrous nickel nitrate which involves the partially overlapping nucleation and growth phases.

  11. Polyelectrolyte microcapsules as ionic liquid reservoirs within ionomer membrane to confer high anhydrous proton conductivity

    Science.gov (United States)

    Zhang, Haoqin; Wu, Wenjia; Li, Yifan; Liu, Yong; Wang, Jingtao; Zhang, Bing; Liu, Jindun

    2015-04-01

    Herein, novel composite membranes are prepared by embedding methacrylic acid polyelectrolyte microcapsules (PMCs) into sulfonated poly(ether ether ketone) (SPEEK) matrix, followed by impregnating imidazole-type ionic liquids (ILs). Within the composite membrane, the lumens of PMCs act as IL reservoirs, which provide large space for IL storage and thus significantly elevate the IL uptake. The IL leaching measurement suggests that the cross-linked shells of PMCs manipulate the IL release, endowing the composite membrane with high IL retention. Moreover, the high IL retention renders the composite membrane more anhydrous hopping sites (e.g., the imidazole groups on IL and the acid-base pairs between imidazole and sulfonic acid groups), imparting a facilitated proton conduction via Grotthuss mechanism. In particular, the composite membrane containing 12% PMCs achieves a high anhydrous proton conductivity of 33.7 mS cm-1 at 150 °C. The same membrane also exhibits a surprising steady-state IL retention of 36.9% after leaching in liquid water.

  12. Structural characterization of anhydrous naloxone- and naltrexone hydrochloride by high resolution laboratory X-ray powder diffraction and thermal analysis.

    Science.gov (United States)

    Sugimoto, Kunihisa; Dinnebier, Robert E; Zakrzewski, Marek

    2007-12-01

    The crystal structures of the analgesic compounds anhydrous naloxone and naltrexone hydrochloride were determined ab initio from high resolution laboratory X-ray powder diffraction data. Both compounds crystallize in the orthorhombic space group P2(1)2(1)2(1) with lattice parameters of a = 14.6588(10) A, b = 17.4363(9) A, c = 7.96200(22) A, and V = 2035.06(23) A(3) for naloxone hydrochloride and a = 15.4560(5) A, b = 14.9809(4) A, c = 7.84121(18) A, and V = 1815.58(11) A(3) for naltrexone hydrochloride. The crystal structure of anhydrous naloxone hydrochloride forms one-dimensional chains through hydrogen bonds. In the crystal structure of anhydrous naltrexone hydrochloride, two-dimensional sheets are formed by hydrogen bonds. The dehydration processes of naloxone hydrochloride dehydrate and naltrexone hydrochloride tetrahydrate was analyzed by DTA, DSC, TG, and MG.

  13. Microbial degradation of pyridine using Pseudomonas sp. and isolation of plasmid responsible for degradation.

    Science.gov (United States)

    Mohan, S Venkata; Sistla, Srinivas; Guru, R Kumar; Prasad, K Krishna; Kumar, C Suresh; Ramakrishna, S V; Sarma, P N

    2003-01-01

    Pseudomonas (PI2) capable of degrading pyridine was isolated from the mixed population of the activated sludge unit which was being used for treating complex effluents, the strain was characterized. Aerobic degradation of pyridine was studied with the isolated strain and the growth parameters were evaluated. Pyridine degradation was further conformed by chromatography (HPLC) analysis. The process parameters like biomass growth and dissolved oxygen consumption were monitored during pyridine degradation. In order to conform with the plasmid capability to degrade pyridine, the requisite plasmid was isolated and transferred to DH 5alpha Escherichia coli. The subsequent biodegradation studies revealed the ability of the transformed plasmid capability to degrade the pyridine.

  14. Highly Efficient and Versatile Synthesis of Some Important Precursors from 1,6-Anhydrous-β-D-glucopyranose as a Green Starting Material

    Institute of Scientific and Technical Information of China (English)

    WEI Guohua; CAI Chao; DU Yuguo

    2009-01-01

    Some important precursors (1,6-anhydrous-2-deoxy-2-azido-β-D-glucopyranose (3),1,6-anhydrous-2-deoxy-2-azido-3,4-di-O-benzyl-β-D-mannopyranose (5), 1,6:2,3-dianhydrouso-β-D-glucopyranose (6), 1,6-anhydrous-3-deoxy-3-azido-β-D-glucopyranose (10) and 1,6-anhydrous-2,4-di-O-benzoyl-β-D-glucopyranose (11)) for complex oligosaccharide synthesis were readily prepared from a green starting material 1,6-anhydrous-β-D-glucopyranose in one or two steps with moderate to high yields.These improved methods established herein will greatly facilitate the assembly of some complex oligosaccharides for the biological study.

  15. Detection of anhydrous hydrochloric acid, HCl, in IRC+10216 with the Herschel SPIRE and PACS spectrometers

    CERN Document Server

    Cernicharo, J; Barlow, M J; Agundez, M; Royer, P; Vandenbussche, B; Wesson, R; Polehampton, E T; De Beck, E; Blommaert, J A D L; Daniel, F; De Meester, W; Exter, K M; Feuchtgruber, H; Gear, W K; Goicoechea, J R; Gomez, H L; Groenewegen, M A T; Hargrave, P C; Huygen, R; Imhof, P; Ivison, R J; Jean, C; Kerschbaum, F; Leeks, S J; Lim, T L; Matsuura, M; Olofsson, G; Posch, T; Regibo, S; Savini, G; Sibthorpe, B; Swinyard, B M; Vandenbussche, B; Waelkens, C

    2010-01-01

    We report on the detection of anhydrous hydrochloric acid (hydrogen chlorine, HCl) in the carbon-rich star IRC+10216 using the spectroscopic facilities onboard the Herschel satellite. Lines from J=1-0 up to J=7-6 have been detected. From the observed intensities, we conclude that HCl is produced in the innermost layers of the circumstellar envelope with an abundance relative to H2 of 5x10^-8 and extends until the molecules reach its photodissociation zone. Upper limits to the column densities of AlH, MgH, CaH, CuH, KH, NaH, FeH, and other diatomic hydrides have also been obtained.

  16. Crystallization behavior of anhydrous milk fat-sunflower oil wax blends.

    Science.gov (United States)

    Kerr, Rebekah M; Tombokan, Xenia; Ghosh, Supriyo; Martini, Silvana

    2011-03-23

    This research evaluates the effect of sunflower oil wax (SFOw) addition on the crystallization behavior and functional properties of anhydrous milk fat (AMF). Induction times of nucleation, melting behavior, microstructure of crystals, and hardness were evaluated for samples of pure AMF and AMF with 0.1 and 0.25% SFOw. Results from this research show that the addition of waxes induced the onset of crystallization of AMF by inducing its nucleation, as evidenced by decreased induction times of nucleation and the formation of smaller crystals. Crystal growth after tempering was also promoted by waxes, and significantly harder lipid networks were obtained. Results presented in this paper suggest that SFOw can be used as an additive to alter the physiochemical properties of low trans-fatty acid lipids.

  17. Solidus and liquidus temperatures and mineralogies for anhydrous garnet-lherzolite to 15 GPa

    Science.gov (United States)

    Herzberg, C. T.

    1983-01-01

    Strong convergence is noted, in experimental data for systems pertaining to anhydrous fertile garnet-lherzolite in the 6.5-15 GPa range, either to a common temperature or to temperatures differing by only about 100 C. The major element composition of magmas generated by even minor degrees of partial melting may be similar to the composition of the primordial, bulk silicate earth in an upper mantle stratigraphic column more than 160 km deep. Whether or not the solidus and liquidus intersect, the liquidus mineralogy for undepleted garnet-lherzolite compositions is found to change from olivine, at low pressures, to pyroxene, garnet, or a solid solution of both, at pressures greater than 10-15 GPa.

  18. SIMULATION OF THE DISTILLATION BY PRESSURE REDUCTION TO OBTAIN ANHYDROUS ETHANOL

    Directory of Open Access Journals (Sweden)

    Yeney Lauzurique Guerra

    2016-10-01

    Full Text Available In this work the distillation by pressure reduction was evaluated through the HYSYS v3.2 process simulator. Due to the lack of data in the consulted bibliography to perform the simulation, the STATGRAPHICS Centurion XVI software was used to obtain a response surface that would define optimal operating conditions. The property package selected to work was based on the Margules model. An anhydrous ethanol molar composition of 0.9917 was obtained. Temperature profiles were analyzed as well as liquid and vapor molar flows and dehydration column composition profiles. The influence of operating parameters on the efficiency of simulated technology was determined by analyzing one case study. According to economic evaluation, the implementation of this technology is not economically profitable; taking into account current prices and costs mostly due to high energy consumption and construction costs of the tower. This result contributes to the pursuit of other profitable technologies from the economic point of view.

  19. Correlated Nitrogen And Carbon Anomalies In An Anhydrous Interplanetary Dust Particles

    Energy Technology Data Exchange (ETDEWEB)

    Floss, C; Stadermann, F J; Bradley, J; Dai, Z; Graham, G

    2003-10-31

    Given the ubiquitous presence of H and N isotopic anomalies in interplanetary dust particles (IDPs) and their probable association with carbonaceous material, the lack of similar isotopic anomalies in C has been a major conundrum. We report here the first observation of correlated N and C isotopic anomalies in organic matter from an anhydrous non-cluster IDP. The {sup 15}N composition of the anomalous region is the highest seen to date in an IDP and is accompanied by a moderate depletion in {sup 13}C. Theoretical models suggest that low temperature formation of organic compounds in cold interstellar molecular clouds does produce C and N fractionations, but it remains to be seen if these models can reproduce the specific effects we observe here.

  20. Distribution and recovery of nitrogen-15-labeled liquid anhydrous ammonia among various soil fractions

    Energy Technology Data Exchange (ETDEWEB)

    Norman, R.J.; Kurtz, L.T.; Stevenson, F.J.

    Since liquid anhydrous ammonia (LAA) is a major N fertilizer, information was sought about the proportions of LAA that enter into various combinations in soils. Liquid anhydrous NH/sub 3/, labeled with /sup 15/N was injected into three soils (Drummer, Typic Haplaquoll; Blount, Aeric Ochraqualf; Cisne, Mollic Albaqualf) in the laboratory at a rate equivalent to a field application of 206 kg N ha /sup 1/ in 76.2 cm knife-spacings. At 1, 7, 14, 28, 56, and 112 d after application, fertilizer N present in different soil fractions was determined in five concentric zones with radii of 0 to 1.5, 1.5 to 3.0, 3.0 to 4.5, 4.5 to 6.0, and 6.0 to 7.0 cm around the point of application. Depending on the soil, from 68 to 83% of the applied /sup 15/N was accounted for as (exchangeable NH/sub 4//sup +/ + NO/sub 3//sup -/ + NO/sub 2//sup -/)-N by the 112th day following application, the remainder being accounted for as clay-fixed NH/sub 4//sup +/ (1.9-4.9%), organic matter-fixed NH/sub 3/ (4.0-6.0%), and biologically immobilized organic N (3.9-9.3%). From 50 to 70% of the organic matter-fixed NH/sub 3/-N was released by hydrolysis with dilute KOH solution as compared to 10 to 15% for the immobilized N. Total recovery of /sup 15/N at 112 d ranged from 77% for the Cisne soil to about 97% for the Drummer and Blount soils. Lateral distributions and transformations of NH/sub 4//sup +/ and NO/sub 3//sup -/ and pH trends after LAA applications were similar to those reported by previous investigators.

  1. Effects of coffee and caffeine anhydrous on strength and sprint performance.

    Science.gov (United States)

    Trexler, Eric T; Smith-Ryan, Abbie E; Roelofs, Erica J; Hirsch, Katie R; Mock, Meredith G

    2016-09-01

    Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300 mg flat dose; yielding 3-5 mg/kg bodyweight), COF (8.9 g; 303 mg caffeine), or placebo (PLA; 3.8 g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p = .04), but not PLA (p = .99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p > .05). There were no sprint × treatment interactions for PP or TW (p > .05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.

  2. Composite polymer electrolyte containing ionic liquid and functionalized polyhedral oligomeric silsesquioxanes for anhydrous PEM applications.

    Science.gov (United States)

    Subianto, Surya; Mistry, Mayur K; Choudhury, Namita Roy; Dutta, Naba K; Knott, Robert

    2009-06-01

    A new type of supported liquid membrane was made by combining an ionic liquid (IL) with a Nafion membrane reinforced with multifunctional polyhedral oligomeric silsesquioxanes (POSSs) using a layer-by-layer strategy for anhydrous proton-exchange membrane (PEM) application. The POSS was functionalized by direct sulfonation, and the sulfonated POSS (S-POSS) was incorporated into Nafion 117 membranes by the infiltration method. The resultant hybrid membrane shows strong ionic interaction between the Nafion matrix and the multifunctional POSS, resulting in increased glass transition temperature and thermal stability at very low loadings of S-POSS (1%). The presence of S-POSS has also improved the proton conductivity especially at low humidities, where it shows a marked increase due to its confinement in the ionic domains and promotes water uptake by capillary condensation. In order to achieve anhydrous conductivity, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) was incorporated into these membranes to provide proton conduction in the absence of water. Although the incorporation of an IL shows a plasticizing effect on the Nafion membrane, the S-POSS composite membrane with an IL shows a higher modulus at high temperatures compared to Nafion 117 and a Nafion-IL membrane, with significantly higher proton conductivity (5 mS/cm at 150 degrees C with 20% IL). This shows the ability of the multifunctional POSS and IL to work symbiotically to achieve the desirable proton conductivity and mechanical properties of such membranes by enhancing the ionic interaction within the material.

  3. Crystal structure of aspartame anhydrate from powder diffraction data. Structural aspects of the dehydration process of aspartame

    NARCIS (Netherlands)

    Guguta, C.; Meekes, H.L.M.; Gelder, R. de

    2006-01-01

    Aspartame has three pseudo-polymorphic forms, two hydrates and a hemi-hydrate, for which crystal structures were determined from single-crystal diffraction data. This paper presents the crystal structure of the anhydrate, which was obtained by dehydrating the hemi-hydrate. The crystal structure of a

  4. Anhydrous ZnCl2: A Highly Efficient Reagent for Facile and Regioselective Conversion of Epoxides to β-Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Ronak Eisavi

    2016-01-01

    Full Text Available Facile conversion of structurally different epoxides to the corresponding β-chlorohydrins was carried out successfully with anhydrous ZnCl2 in CH3CN. The reactions were carried out within 10-50 min to give β-chlorohydrins with perfect regioselectivity and high yields (80-97%.

  5. Biomarker generation from Type II-S kerogens in claystone and limestone during hydrous and anhydrous pyrolysis

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Koopmans, M.P.; Carson, F.C.; Lewan, M.D.

    1998-01-01

    A claystone and a limestone containing immature Type II-S kerogen were thermally matured in the presence and absence of water, to study the influence of water and clay minerals on the generation of biomarkers. In contrast to hydrous pyrolysis, anhydrous pyrolysis of the claystone did not generate bi

  6. 75 FR 70687 - Storage and Handling of Anhydrous Ammonia Standard; Extension of the Office of Management and...

    Science.gov (United States)

    2010-11-18

    ... containers and systems to store and transfer anhydrous ammonia in the workplace. DATES: Comments must be... INFORMATION.'' Docket: To read or download comments or other material in the docket, go to http://www....g., copyrighted material) is not publicly available to read or download through the Web site....

  7. TEM and NanoSIMS Study of Hydrated/Anhydrous Phase Mixed IDPs: Cometary or Asteroidal Origin?

    Science.gov (United States)

    Nakamura, K.; Messenger, S.; Keller, L. P.

    2005-01-01

    Chondritic interplanetary dust particles (IDPs) are subdivided into (1) particles that form highly porous aggregates (chondritic porous "CP" IDPs), and (2) smooth particles ("CS" IDPs). Infrared (IR) spectroscopy has been a valuable tool for non-destructively determining the bulk mineralogy of IDPs. Most IDPs fall within three distinct IR groups: (1) olivine-rich particles, (2) pyroxene-rich particles, and (3) phyllosilicate-rich particles. From the IR studies, IDPs dominated by anhydrous minerals tend to be fine grained (CP), while phyllosilicate-rich IDPs are mostly CS. CP IDPs have been linked to cometary sources based on their compositions, spectral properties, and atmospheric entry velocities. Since no spectral signatures of hydrated minerals have been detected in comets, CS IDPs are thought to derive from primitive asteroids. Transmission electron microscopy (TEM) studies have revealed that the mineralogical distinctions between CP and CS IDPs are not always clear. Previous investigators have reported trace amounts of hydrous minerals in dominantly anhydrous particles. A better understanding of these particles will help to elucidate whether there is a genetic relationship between anhydrous and hydrated IDPs, provide insight into the earliest stages of aqueous alteration of primitive materials, and may help to determine whether comets have experienced any aqueous processing. Here we report a combined TEM and isotopic imaging study of an unusual anhydrous IDP with hydrated phases. Additional information is included in the original extended abstract.

  8. Lewis acid activation of pyridines for nucleophilic aromatic substitution and conjugate addition.

    Science.gov (United States)

    Abou-Shehada, Sarah; Teasdale, Matthew C; Bull, Steven D; Wade, Charles E; Williams, Jonathan M J

    2015-03-01

    A clean, mild and sustainable method for the functionalization of pyridines and their analogues is reported. A zinc-based Lewis acid is used to activate pyridine and its analogues towards nucleophilic aromatic substitution, conjugate addition, and cyclization reactions by binding to the nitrogen on the pyridine ring and activating the pyridine ring core towards further functionalization. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Synthesis and Catalytic Asymmetric Reaction of Chiral Pyridine Prolinol Derivatives

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao; ZHANG Yong-Xin; DU Da-Ming; HUA Wen-Ting

    2003-01-01

    @@ The enantioselective reduction of prochiral ketones with borane in the presence of a chiral ligand leading to enantiomerically pure secondary alcohols has received considerable attention in recent years. [1] Enantiomerically pure secondary alcohols are important intermediates for the synthesis of various other organic compounds such as halides, esters, ethers, ketones and amines. To the best of our knowledge, the use of pyridine prolinol derivatives in the reduction of ketones has not been reported so far. Thus, it should be of interest to investigate the catalytic a bility of such ligands. We have an ongoing project in the synthesis and application of chiral pyridine derivatives in chiral molecular recognition[2] and we want to evaluate the effect resulting from the introduction of a pyridinyl moiety onto the catalysts. We expect that the cooperation of pyridine unit and chiral prolinol unit in new ligands may result in unique properties for catalytic reaction.

  10. SULFONATED POLYIMIDES CONTAINING PYRIDINE GROUPS AS PROTON EXCHANGE MEMBRANE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Rui Lei; Chuan-qing Kang; Yun-jie Huang; Xue-peng Qiu; Xiang-ling Ji; Wei Xing; Lian-xun Gao

    2011-01-01

    A series of sulfonated polyimides (SPIs) containing pyridine groups were prepared by direct polycondensation from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA),4,4′-diaminodiphenyl ether-2,2′-disulfonic acid (ODADS) and 4-(4-methoxy)phenyl-2,6-bis(4-aminophenyl)pyridine (DAM).The resulting copolymers displayed good solubility in common organic solvents.Flexible,transparent,tough membranes were obtained via solution casting.All the films showed high thermal stability with desulfonation temperature over 300℃.They exhibited prominent mechanical properties with Young's modulus around 2.0 GPa.High proton conductivity (0.23 S/em at 100% RH) was also observed.More importantly,the new materials exhibited low water uptake (30 wt%-75 wt% at 80℃) and improved water stability,which were attributed to the acid-base interaction between sulfonic acid and pyridine functional groups.

  11. The regioselective iodination of quinolines, quinolones, pyridones, pyridines and uracil.

    Science.gov (United States)

    Dutta, Uttam; Deb, Arghya; Lupton, David W; Maiti, Debabrata

    2015-12-28

    A radical based direct C-H iodination protocol for quinolines, quinolones, pyridones, pyridines, and uracil has been developed. The iodination occurs in a C3 selective manner for quinolines and quinolones. Pyridones and pyridines undergo C3 and C5 iodination, while dimethyl uracil undergoes C5 iodination. Scope of the method was demonstrated through the rapid synthesis of both electron rich as well as electron poor heteroaromatic iodides. The protocol was found to be scalable and general, while a mechanism has been proposed.

  12. Nuclear alkylated pyridine aldehyde polymers and conductive compositions thereof

    Science.gov (United States)

    Rembaum, A.; Singer, S. (Inventor)

    1970-01-01

    A thermally stable, relatively conductive polymer was disclosed. The polymer was synthesized by condensing in the presence of catalyst a 2, 4, or 6 nuclear alklylated 2, 3, or 4 pyridine aldehyde or quaternary derivatives thereof to form a polymer. The pyridine groups were liked by olefinic groups between 2-4, 2-6, 2-3, 3-4, 3-6 or 4-6 positions. Conductive compositions were prepared by dissolving the quaternary polymer and an organic charge transfer complexing agent such as TCNQ in a mutual solvent such as methanol.

  13. 2-(Pyridin-2-yl-1,3-oxathiane

    Directory of Open Access Journals (Sweden)

    David Turner

    2012-06-01

    Full Text Available The title compound, C9H11NOS, exhibits a unique structural motif, with free rotation of the aliphatic oxathiane ring about the C—C bond connecting this moiety to the aromatic pyridine ring. The structure elucidation was undertaken due to its potential as a bidentate ligand for organometallic complexes. The oxathiane ring adopts the expected chair conformation, with the S atom in proximity to the N atom on the pyridine ring. The corresponding S—C—C—N torsion angle is 69.07 (14°. In the crystal, molecules aggregate as centrosymmetric pairs connected by pairs of C—H...N hydrogen bonds.

  14. Synthesis of some new Thieno[2,3-b]pyridines, Pyrimidino[4',5':4,5]thieno[2,3-b]pyridine and Pyridines Incorporating 5-Bromobenzofuran-2-yl Moiety.

    Science.gov (United States)

    Abdelriheem, Nadia Abdelhamed; Ahmad, Sayed Abdel-Kader; Abdelhamid, Abdou Osman

    2015-01-07

    2-Sulfanyl-6-(2-thienyl)pyridine-3-carbonitrile, 1-Amino-6-(5-bromo-benzofuran-2-yl)-2-oxo-1,2-dihydro-pyridine-3-carbonitrile, thieno[2,3-b]pyridins, pyrimidino[4',5':4,5] thieno[2,3-b]pyridine, quinazoline and carbamate derivatives were synthesized from sodium 3-(5-bromobenzofuran-2-yl)-3-oxoprop-1-en-1-olate with. The newly synthesized compounds were elucidated by elemental analysis, spectral data, and alternative synthesis whenever possible and chemical transportation.

  15. The Role of Hydrogen Bonding on Laminar Burning Velocity of Hydrous and Anhydrous Ethanol Fuel with Small Addition of n-Heptane

    Directory of Open Access Journals (Sweden)

    I Made Suarta

    2016-01-01

    Full Text Available The molecular structure of mixed hydrous and anhydrous ethanol with up to 10% v n-heptane had been studied. The burning velocity was examined in a cylindrical explosion combustion chamber. The result showed that the burning velocity of hydrous ethanol is higher than anhydrous ethanol and n-heptane at stoichiometric, rich, and very rich mixtures. The burning velocity of hydrous ethanol with n-heptane drops drastically compared to the burning velocity of anhydrous ethanol with n-heptane. It is caused by two reasons. Firstly, there was a composition change of azeotropic hydrous ethanol molecules within the mixture of fuel. Secondly, at the same volume the number of ethanol molecules in hydrous ethanol was less than in anhydrous ethanol at the same composition of the n-heptane in the mixture. At the mixture of anhydrous ethanol with n-heptane, the burning velocity decreases proportionally to the addition of the n-heptane composition. The burning velocity is between the velocities of anhydrous ethanol and n-heptane. It shows that the burning velocity of anhydrous ethanol mixed with n-heptane is only influenced by the mixture composition.

  16. Pulse radiolysis of pyridine and methylpyridines in aqueous solutions

    DEFF Research Database (Denmark)

    Solar, S.; Getoff, N.; Sehested, K.

    1993-01-01

    The radicals formed from pyridine, 3-methylpyridine, 3,5-dimethylpyridine, 2,6-dimethylpyridine and 2,4,6-trimethylpyridine by attack of H, e(aq)-, OH and O.- in aqueous solutions were investigated by pulse radiolysis in the pH-range 1-13.8. The UV-vis. absorption spectra as well as the formation...

  17. A Concise Synthesis of Monoterpene Pyridine Alkaloid Aucubinine B

    Institute of Scientific and Technical Information of China (English)

    杨晓霞; 赵景瑞; 贾学顺; 杨力维; 翟宏斌

    2003-01-01

    Aucubinine B (4), a monoterpene alkaloid obtained from the metabolites of aucubin in the presence of human intestinal bacteria, has been synthesized from 3-bromo-4-pyridinecarboxaldehyde (5) in four steps with 39% overall yield. The construction of the cyclopenta[c]pyridine intermediate (7) was realized by an intramolecular Heck reaction.

  18. Facile and Rapid Access to Poly Functionalized Pyridine Derivatives

    Institute of Scientific and Technical Information of China (English)

    Shinde Pravin V; Shingate Bapurao B; Shingare Murlidhar S

    2011-01-01

    An efficient and greener protocol for the synthesis of poly functionalized pyridines using tetra-n-butyl ammo-nium fluoride (TBAF) in water is established. Remarkable advantages of the present synthetic strategy over the others are shorter reaction times, higher isolated yields, reuse of catalytic system, simple work-up procedure and more especially its applicability to heteryl and aliphatic aldehydes.

  19. Investigations into the mechanisms of pyridine ring cleavage in vismodegib.

    Science.gov (United States)

    Khojasteh, S Cyrus; Yue, Qin; Ma, Shuguang; Castanedo, Georgette; Chen, Jacob Z; Lyssikatos, Joseph; Mulder, Teresa; Takahashi, Ryan; Ly, Justin; Messick, Kirsten; Jia, Wei; Liu, Lichuan; Hop, Cornelis E C A; Wong, Harvey

    2014-03-01

    Vismodegib (Erivedge, GDC-0449) is a first-in-class, orally administered small-molecule Hedgehog pathway inhibitor that is approved for the treatment of advanced basal cell carcinoma. Previously, we reported results from preclinical and clinical radiolabeled mass balance studies in which we determined that metabolism is the main route of vismodegib elimination. The metabolites of vismodegib are primarily the result of oxidation followed by glucuronidation. The focus of the current work is to probe the mechanisms of formation of three pyridine ring-cleaved metabolites of vismodegib, mainly M9, M13, and M18, using in vitro, ex vivo liver perfusion and in vivo rat studies. The use of stable-labeled ((13)C2,(15)N)vismodegib on the pyridine ring exhibited that the loss of carbon observed in both M9 and M13 was from the C-6 position of pyridine. Interestingly, the source of the nitrogen atom in the amide of M9 was from the pyridine. Evidence for the formation of aldehyde intermediates was observed using trapping agents as well as (18)O-water. Finally, we conclude that cytochrome P450 is involved in the formation of M9, M13, and M18 and that M3 (the major mono-oxidative metabolite) is not the precursor for the formation of these cleaved products; rather, M18 is the primary cleaved metabolite.

  20. Directed solid-phase synthesis of trisubstituted imidazo[4,5-c]pyridines and imidazo[4,5-b]pyridines.

    Science.gov (United States)

    Lemrová, Barbora; Smyslová, Petra; Popa, Igor; Oždian, Tomáš; Zajdel, Pawel; Soural, Miroslav

    2014-10-13

    An efficient method is described for the solid-supported synthesis of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines from 2,4-dichloro-3-nitropyridine. The key pyridine building block was reacted with polymer-supported amines, followed by replacement of the second chlorine with amines, nitro group reduction, and imidazole ring closure with aldehydes. Depending on the combination of polymer-supported and solution-phase reagents, the strategy allowed for the simple preparation of the target trisubstituted derivatives with variable positioning of the pyridine nitrogen atom. Additionally, after a slight modification of the method, the preparation of strictly isomeric imidazopyridines was possible.

  1. Preparation and Characterization of Anhydrous Magnesium Chloride in Organic Solvent%有机溶剂法无水氯化镁的制备与表征

    Institute of Scientific and Technical Information of China (English)

    周宁波; 陈白珍; 何新快; 李义兵

    2005-01-01

    Ammonium carnallite was synthesized by hydrated magnesium chloride in salt lake and ammonium chloride solution. Dehydrated ammonium carnallite was dissolved in methanol under low temperature by feeding ammonia, to prepare anhydrous magnesium chloride. The results show that anhydrous magnesium chloride contains magnesium oxide in an amount less than 0.1% by weight, the yield of magnesium chloride was above 99.5%. Ammonium carnallite, ammoniation magnesium chloride and anhydrous magnesium chloride were characterized by thermoanalysis, X-ray powder diffraction and scanning electron microscopy.

  2. Determination of impurities in raw light pyridine bases

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, E.G.; Dybkin. L.A.; Galleway, B.J.; Lisina, L.A.; Tsaur, A.G.

    1981-01-01

    An estimate has been made of the annual average content of phenols, cyanides, rhodanides and chlorides in the raw light pyridine bases of the works in the East of the USSR. The mean values of the content of every component in the tests are given, and the amount of water in them is indicated. The bases with the highest content of phenols were those of the Cherepovets Metallurgical Works and the Gubakhin Coke and Chemical Works, and some specimens of the Karagandinsk Metallurgical Works. For most enterprises, the concentration of phenols depended on the time of the year: the phenol content in the specimens was mostly higher in the summer than in the winter. For the works in the East of USSR, the mean annual content of cyanides was 1.5 g/lit. Some enterprises supplied light pyridine bases whose cyanide content was almost ten times less. The pyridine bases of the Karagandinsk Metallurgical Works, especially those with phenolates, have an especially high content of cyanides. For instance, the cyanide content in one test was 8.9 g/lit. The mean annual content of rhodanides in the tested bases was 3.5-4.0 g/lit. The raw light pyridine bases of the Karagandinsk Metallurgical Works, from which a large amount of crystalline salt mixtures precipitates during storage when they contain phenolates, have the highest rhodamine content. The bases of the Chelyabin Metallurgical Works and the Gubakhin Coke and Chemical Works contain the least amount of salts. The mean annual content of phenols in the tests of the works in the East of the USSR is 5%. This is probably less than in the specimens of the works in the Sought of the USSR. It has been established that, besides the above-mentioned impurities, raw light pyridine bases have components which form a dark flake-like precipitate of an unknown composition during storage.

  3. Cross-linked polyvinyl pyridine coated glass particle catalyst support and aqueous composition or polyvinyl pyridine adducted microspheres

    Science.gov (United States)

    Rembaum, Alan (Inventor); Gupta, Amitava (Inventor); Volksen, Willi (Inventor)

    1981-01-01

    Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

  4. Pyridine N-Oxide vs Pyridine Substrates for Rh(III)-Catalyzed Oxidative C-H Bond Functionalization.

    Science.gov (United States)

    Neufeldt, Sharon R; Jiménez-Osés, Gonzalo; Huckins, John R; Thiel, Oliver R; Houk, K N

    2015-08-12

    The origin of the high reactivity and site selectivity of pyridine N-oxide substrates in O-pivaloyl hydroxamic acid-directed Rh(III)-catalyzed (4+2) annulation reactions with alkynes was investigated computationally. The reactions of the analogous pyridine derivatives were previously reported to be slower and to display poor site selectivity for functionalization of the C(2)-H vs the C(4)-H bonds of the pyridine ring. The N-oxide substrates are found to be more reactive overall because the directing group interacts more strongly with Rh. For N-oxide substrates, alkyne insertion is rate-limiting and selectivity-determining in the reaction with a dialkyl alkyne, but C-H activation can be selectivity-determining with other coupling partners such as terminal alkynes. The rates of reaction with a dialkyl alkyne at the two sites of a pyridine substrate are limited by two different steps: C-H activation is limiting for C(2)-functionalization, while alkyne insertion is limiting for C(4)-functionalization. Consistent with the observed poor site selectivity in the reaction of a pyridine substrate, the overall energy barriers for functionalization of the two positions are nearly identical. High C(2)-selectivity in the C-H activation step of the reaction of the N-oxide is due to a cooperative effect of the C-H Brønsted acidity, the strength of the forming C-Rh bond, and intramolecular electrostatic interactions between the [Rh]Cp* and the heteroaryl moieties. On the other hand, some of these forces are in opposition in the case of the pyridine substrate, and C(4)-H activation is moderately favored overall. The alkyne insertion step is favored at C(2) over C(4) for both substrates, and this preference is largely influenced by electrostatic interactions between the alkyne and the heteroarene. Experimental results that support these calculations, including kinetic isotope effect studies, H/D exchange studies, and results using a substituted pyridine, are also described.

  5. Taste Masking of Griseofulvin and Caffeine Anhydrous Using Kleptose Linecaps DE17 by Hot Melt Extrusion.

    Science.gov (United States)

    Juluri, Abhishek; Popescu, Carmen; Zhou, Leon; Murthy, Reena N; Gowda, Vanaja K; Chetan Kumar, P; Pimparade, Manjeet B; Repka, Michael A; Murthy, S Narasimha

    2016-02-01

    The objective of this project was to investigate the potential of Kleptose Linecaps DE17 (KLD) in masking the unpleasant/bitter taste of therapeutic agents by hot melt extrusion (HME). Griseofulvin (GRI) and caffeine anhydrous (CA) were used as a bitter active pharmaceutical ingredient (API) model drugs. Thermogravimetric studies confirmed the stability of GRI, CA, and KLD at the employed extrusion temperatures. The differential scanning calorimetry (DSC) studies revealed a characteristic melting endotherm of GRI at 218-220°C and CA at 230-232°C in the physical mixtures as well as in all extrudates over the period of study, indicating the crystalline nature of drug. HME of KLD was achieved only in the presence of plasticizer. Among the several plasticizers investigated, xylitol showed improved processability of KLD at 15% w/w concentration. Dissolution studies of HME extrudates using simulated salivary medium exhibited ∼threefold less release compared to physical mixture at the end of 5 min (the lesser drug release, better the taste masking efficiency). Furthermore, the results from the sensory evaluation of products in human panel demonstrated strong bitter taste in the case of physical mixture compared to the HME formulation, suggesting the potential of Kleptose Linecaps DE17 as taste masking polymer in melt extruded form.

  6. Structure, Solubility and Stability of Orbifloxacin Crystal Forms: Hemihydrate versus Anhydrate.

    Science.gov (United States)

    Santos, Olimpia Maria Martins; Freitas, Jennifer Tavares Jacon; Cazedey, Edith Cristina Laignier; de Araújo, Magali Benjamim; Doriguetto, Antonio Carlos

    2016-03-09

    Orbifloxacin (ORBI) is a widely used antimicrobial drug of the fluoroquinolone class. In the official pharmaceutical compendia the existence of polymorphism in this active pharmaceutical ingredient (API) is reported. No crystal structure has been reported for this API and as described in the literature, its solubility is very controversial. Considering that different solid forms of the same API may have different physicochemical properties, these different solubilities may have resulted from analyses inadvertently carried out on different polymorphs. The solubility is the most critical property because it can affect the bioavailability and may compromise the quality of a drug product. The crystalline structure of ORBI determined by SCXRD is reported here for the first time. The structural analysis reveals that the ORBI molecule is zwitterionic and hemihydrated. ORBI hemihydrated form was characterized by the following techniques: TG/DTA, FTIR-ATR, and PXRD. A second crystalline ORBI form is also reported: the ORBI anhydrous form was obtained by heating the hemihydrate. These ORBI solid forms were isomorphous, since no significant change in unit cell and space group symmetry were observed. The solid-state phase transformation between these forms is discussed and the equilibrium solubility data were examined in order to check the impact of the differences observed in their crystalline structures.

  7. Structure, Solubility and Stability of Orbifloxacin Crystal Forms: Hemihydrate versus Anhydrate

    Directory of Open Access Journals (Sweden)

    Olimpia Maria Martins Santos

    2016-03-01

    Full Text Available Orbifloxacin (ORBI is a widely used antimicrobial drug of the fluoroquinolone class. In the official pharmaceutical compendia the existence of polymorphism in this active pharmaceutical ingredient (API is reported. No crystal structure has been reported for this API and as described in the literature, its solubility is very controversial. Considering that different solid forms of the same API may have different physicochemical properties, these different solubilities may have resulted from analyses inadvertently carried out on different polymorphs. The solubility is the most critical property because it can affect the bioavailability and may compromise the quality of a drug product. The crystalline structure of ORBI determined by SCXRD is reported here for the first time. The structural analysis reveals that the ORBI molecule is zwitterionic and hemihydrated. ORBI hemihydrated form was characterized by the following techniques: TG/DTA, FTIR-ATR, and PXRD. A second crystalline ORBI form is also reported: the ORBI anhydrous form was obtained by heating the hemihydrate. These ORBI solid forms were isomorphous, since no significant change in unit cell and space group symmetry were observed. The solid-state phase transformation between these forms is discussed and the equilibrium solubility data were examined in order to check the impact of the differences observed in their crystalline structures.

  8. Laboratory-Scale Membrane Reactor for the Generation of Anhydrous Diazomethane.

    Science.gov (United States)

    Dallinger, Doris; Pinho, Vagner D; Gutmann, Bernhard; Kappe, C Oliver

    2016-07-15

    A configurationally simple and robust semibatch apparatus for the in situ on-demand generation of anhydrous solutions of diazomethane (CH2N2) avoiding distillation methods is presented. Diazomethane is produced by base-mediated decomposition of commercially available Diazald within a semipermeable Teflon AF-2400 tubing and subsequently selectively separated from the tubing into a solvent- and substrate-filled flask (tube-in-flask reactor). Reactions with CH2N2 can therefore be performed directly in the flask without dangerous and labor-intensive purification operations or exposure of the operator to CH2N2. The reactor has been employed for the methylation of carboxylic acids, the synthesis of α-chloro ketones and pyrazoles, and palladium-catalyzed cyclopropanation reactions on laboratory scale. The implementation of in-line FTIR technology allowed monitoring of the CH2N2 generation and its consumption. In addition, larger scales (1.8 g diazomethane per hour) could be obtained via parallelization (numbering up) by simply wrapping several membrane tubings into the flask.

  9. Vibrational Spectroscopy and Phonon-Related Properties of the L-Aspartic Acid Anhydrous Monoclinic Crystal.

    Science.gov (United States)

    Silva, A M; Costa, S N; Sales, F A M; Freire, V N; Bezerra, E M; Santos, R P; Fulco, U L; Albuquerque, E L; Caetano, E W S

    2015-12-10

    The infrared absorption and Raman scattering spectra of the monoclinic P21 l-aspartic acid anhydrous crystal were recorded and interpreted with the help of density functional theory (DFT) calculations. The effect of dispersive forces was taken into account, and the optimized unit cells allowed us to obtain the vibrational normal modes. The computed data exhibits good agreement with the measurements for low wavenumbers, allowing for a very good assignment of the infrared and Raman spectral features. The vibrational spectra of the two lowest energy conformers of the l-aspartic molecule were also evaluated using the hybrid B3LYP functional for the sake of comparison, showing that the molecular calculations give a limited description of the measured IR and Raman spectra of the l-aspartic acid crystal for wavenumbers below 1000 cm(-1). The results obtained reinforce the need to use solid-state calculations to describe the vibrational properties of molecular crystals instead of calculations for a single isolated molecule picture even for wavenumbers beyond the range usually associated with lattice modes (200 cm(-1) < ω < 1000 cm(-1)).

  10. Investigation of the Dermal Absorption and Irritation Potential of Sertaconazole Nitrate Anhydrous Gel

    Directory of Open Access Journals (Sweden)

    Mahima Manian

    2016-07-01

    Full Text Available Effective topical therapy of cutaneous fungal diseases requires the delivery of the active agent to the target site in adequate concentrations to produce a pharmacological effect and inhibit the growth of the pathogen. In addition, it is important to determine the concentration of the drug in the skin in order to evaluate the subsequent efficacy and potential toxicity for topical formulations. For this purpose, an anhydrous gel containing sertaconazole nitrate as a model drug was formulated and the amount of the drug in the skin was determined by in vitro tape stripping. The apparent diffusivity and partition coefficients were then calculated by a mathematical model describing the dermal absorption as passive diffusion through a pseudo-homogenous membrane. The skin irritation potential of the formulation was also assessed by using the in vitro Epiderm™ model. An estimation of the dermal absorption parameters allowed us to evaluate drug transport across the stratum corneum following topical application. The estimated concentration for the formulation was found to be higher than the MIC100 at the target site which suggested its potential efficacy for treating fungal infections. The skin irritation test showed the formulation to be non-irritating in nature. Thus, in vitro techniques can be used for laying the groundwork in developing efficient and non-toxic topical products.

  11. Free fatty acids and their esters modulate isothermal crystallization of anhydrous milk fat.

    Science.gov (United States)

    Bayard, Mathilde; Leal-Calderon, Fernando; Cansell, Maud

    2017-03-01

    The effect of free fatty acids with different chain lengths or unsaturation degree on anhydrous milk fat (AMF) crystallization was evaluated. The impact of esterification was also studied using three triglycerides. Melted blends containing the additives at concentrations lower than 12wt.% were quenched at 25°C and isothermal crystallization was monitored by pulsed low-resolution nuclear magnetic resonance. In parallel, polarized light microscopy was used to observe the microstructure. Compounds based on long chain saturated fatty acids, i.e. palmitic, stearic, eicosanoic acids, tripalmitin and tristearin accelerated crystallization. Conversely, propanoic, hexanoic and oleic acids slowed down the process, while triacetin had no impact. Interestingly, above a critical concentration, the addition of palmitic, stearic or eicosanoic acids caused a transition from a one-step to two-step process. Gompertz model was used to fit the experimental data and to assess the influence of the molecular properties of the additives on the kinetic parameters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Production of High-Purity Anhydrous Nickel(II Perrhenate for Tungsten-Based Sintered Heavy Alloys

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-04-01

    Full Text Available This paper presents a method for the production of high-purity anhydrous nickel(II perrhenate. The method comprises sorption of nickel(II ions from aqueous nickel(II nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder. This study provides information on the selected properties of the resulting Re-Ni powder. This powder was used as a starting material for the production of 77W-20Re-3Ni heavy alloys. Microstructure examination results and selected properties of the produced sintered heavy alloys were compared to sintered alloys produced using elemental W, Re, and Ni powders. This study showed that the application of anhydrous nickel(II perrhenate in the production of 77W-20Re-3Ni results in better properties of the sintered alloys compared to those made from elemental powders.

  13. Gruusia loeb kokku venelaste jäetud pomme ja sõjaohvreid / Liisi Poll

    Index Scriptorium Estoniae

    Poll, Liisi, 1980-

    2008-01-01

    Vene vägede lahkumist ootavas Gruusias loetakse kokku sõjakaotusi, milleks on inimkaotused, katkenud kaubandus, purustatud infrastruktuur, mahajäetud lõhkekehad. Punase Risti hinnangust sõjapõgenike kohta. Vt. samas: Vene väed lahkuvad endiselt vaid teoreetiliselt

  14. Profil de l'etudiant du premier cycle des etudes medicales de Lome ...

    African Journals Online (AJOL)

    Profil de l'etudiant du premier cycle des etudes medicales de Lome et sa perception de l'enseignement de l'anatomie. ... Journal de la Recherche Scientifique de l'Universite de Lome ... aux différentes questions des paramètres étudiés.

  15. Optical absorption and DFT calculations in L-aspartic acid anhydrous crystals: Charge carrier effective masses point to semiconducting behavior

    Science.gov (United States)

    Silva, A. M.; Silva, B. P.; Sales, F. A. M.; Freire, V. N.; Moreira, E.; Fulco, U. L.; Albuquerque, E. L.; Maia, F. F., Jr.; Caetano, E. W. S.

    2012-11-01

    Density functional theory (DFT) computations within the local-density approximation and generalized gradient approximation in pure form and with dispersion correction (GGA+D) were carried out to investigate the structural, electronic, and optical properties of L-aspartic acid anhydrous crystals. The electronic (band structure and density of states) and optical absorption properties were used to interpret the light absorption measurements we have performed in L-aspartic acid anhydrous crystalline powder at room temperature. We show the important role of the layered spatial disposition of L-aspartic acid molecules in anhydrous L-aspartic crystals to explain the observed electronic and optical properties. There is good agreement between the GGA+D calculated and experimental lattice parameters, with (Δa, Δb, Δc) deviations of (0.029,-0.023,-0.024) (units in Å). Mulliken [J. Chem. Phys.JCPSA60021-960610.1063/1.1740588 23, 1833 (1955)] and Hirshfeld [Theor. Chim. ActaTCHAAM0040-574410.1007/BF00549096 44, 129 (1977)] population analyses were also performed to assess the degree of charge polarization in the zwitterion state of the L-aspartic acid molecules in the DFT converged crystal. The lowest-energy optical absorption peaks related to transitions between the top of the valence band and the bottom of the conduction band involve O 2p valence states and C 1p and O 2p conduction states, with the carboxyl and COOH lateral chain group contributing significantly to the energy band gap. Among the calculated band gaps, the lowest GGA+D (4.49-eV) gap is smaller than the experimental estimate of 5.02 eV, as obtained by optical absorption. Such a wide-band-gap energy together with the small carrier effective masses estimated from band curvatures allows us to suggest that an L-aspartic acid anhydrous crystal can behave as a wide-gap semiconductor. A comparison of effective masses among directions parallel and perpendicular to the L-aspartic molecules layers reveals that charge

  16. On the one pot syntheses of chromeno[4,3-b]pyridine-3-carboxylate and chromeno[3,4-c]pyridine-3-carboxylate and dihydropyridines

    Energy Technology Data Exchange (ETDEWEB)

    Navarrete-Encina, Patricio A.; Vega-Retter, Christian, E-mail: pnavarre@vtr.ne [Universidad de Chile, Santiago (Chile). Facultad de Ciencias Quimicas y Farmaceuticas. Lab. de Sintesis Organica y Fisicoquimica; Salazar, Ricardo; Perez, Karina; Squella, Juan A.; Nunez-Vergara, Luis J. [Universidad de Chile, Santiago (Chile). Fac. de Ciencias Quimicas y Farmaceuticas. Lab. de Bioelectroquimica

    2010-07-01

    Substituted chromenos, dihydropyridines and pyridines have been important in the syntheses of compounds having interesting pharmacological properties. Therefore, we found of interest to synthesize chromenopyridines and chromeno dihydropyridines (i.e., fused chromeno and dihydropyridine or pyridine rings) to further study their biological activity. Here, we propose one-pot syntheses for substituted ethyl-2,4-dimethyl-5-oxo-5H-chromeno[4,3-b]pyridine-3-carboxylates, ethyl-2,4-dimethyl-5-oxo-5H-chromeno[3,4-c]pyridine-3-carboxylates and their respective 1,4-dihydropyridines based on a modified Hantzsch pyridine synthesis using 2-hydroxyaryl aldehydes, with electron withdrawing and electron donating groups on the phenyl ring, as starting reactants. Sixteen compounds were synthesized by the described method and fully characterized. An average yield of 37% was obtained for the different derivatives. (author)

  17. Pyridine-induced Dimensionality Change in Hybrid Perovskite Nanocrystals

    KAUST Repository

    Ahmed, Ghada H.

    2017-05-02

    Engineering the surface energy through careful manipulation of the surface chemistry is a convenient approach to control quantum confinement and structure dimensionality during nanocrystal growth. Here, we demonstrate that the introduction of pyridine during the synthesis of methylammonium lead bromide (MAPbBr) perovskite nanocrystals can transform three-dimensional (3D) cubes into two-dimensional (2D) nanostructures. Density functional theory (DFT) calculations show that pyridine preferentially binds to Pb atoms terminating the surface, driving the selective 2D growth of the nanostructures. These 2D nanostructures exhibit strong quantum confinement effects, high photoluminescence quantum yields in the visible spectral range, and efficient charge transfer to molecular acceptors. These qualities indicate the suitability of the synthesized 2D nanostructures for a wide range of optoelectronic applications.

  18. Pyridine Vapors Detection by an Optical Fibre Sensor

    Directory of Open Access Journals (Sweden)

    Alberto Fernandez-Gutiérrez

    2008-02-01

    Full Text Available An optical fibre sensor has been implemented towards pyridine vapors detection;to achieve this, a novel vapochromic material has been used, which, in solid state, suffers achange in colour from blue to pink-white in presence of pyridine vapours. This complex isadded to a solution of PVC (Poly Vinyl Chloride, TBP (Tributylphosphate andtetrahydrofuran (THF, forming a plasticized matrix; by dip coating technique, the sensingmaterial is fixed onto a cleaved ended optical fibre. The fabrication process was optimizedin terms of number of dips and dipping speed, evaluating the final devices by dynamicrange. Employing a reflection set up, the absorbance spectra and changes in the reflectedoptical power of the sensors were registered to determine their response. A linear relationbetween optical power versus vapor concentration was obtained, with a detection limit of 1ppm (v/v.

  19. Anhydrous octyl-glucoside phase transition from lamellar to isotropic induced by electric and magnetic fields.

    Science.gov (United States)

    Hashim, Rauzah; Sugimura, Akihiko; Nguan, Hock-Seng; Rahman, Matiur; Zimmermann, Herbert

    2017-02-28

    A static deuterium nuclear magnetic resonance ((2)HNMR) technique (magnetic field, B = 7.05 T) was employed to monitor the thermotropic lamellar phase of the anhydrous 1:1 mixture sample of octyl-b-D-glucoside (βOG) and that of partially deuterium labelled at the alpha position on the chain, i.e.,βOG-d2 In the absence of an electric field, the (2)H NMR spectrum of the mixture gives a typical quadrupolar doublet representing the aligned lamellar phase. Upon heating to beyond the clearing temperature at 112 °C, this splitting converts to a single line expected for an isotropic phase. Simultaneous application of magnetic and electric fields (E = 0.4 MV/m) at 85 °C in the lamellar phase, whose direction was set to be parallel or perpendicular to the magnetic field, resulted in the change of the doublet into a single line and this recovers to the initial doublet with time for both experimental geometries. This implies E- and B-field-induced phase transitions from the lamellar to an isotropic phase and a recovery to the lamellar phase again with time. Moreover, these phase transformations are accompanied by a transient current. A similar observation was made in a computational study when an electric field was applied to a water cluster system. Increasing the field strength distorts the water cluster and weakens its hydrogen bonds leading to a structural breakdown beyond a threshold field-strength. Therefore, we suggest the observed field-induced transition is likely due to a structure change of the βOG lamellar assembly caused by the field effect and not due to Joule heating.

  20. 2-Nitro-N′-[1-(pyridin-2-ylethylidene]benzohydrazide

    Directory of Open Access Journals (Sweden)

    Xiaofeng Li

    2011-12-01

    Full Text Available In the title compound, C14H12N4O3, the dihedral angle between the benzene ring and the pyridine ring is 60.9 (2°. The major twist in the molecule occurs about the (NH—(CO—Car—Car (ar = aromatic bond, the relevant torsion angle being 63.97 (12°. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generate R22(8 loops.

  1. Adsorption of Pyridine at the Au(110) - Solution Interface

    Science.gov (United States)

    1990-05-28

    Electroanalytical Chemistry Guelph-Waterloo Center for Graduate Work in Chemistry Waterloo, Campus Department of Chemistry University of Waterloo...Year, Month, Day) S PAGE COUNT Technical FROM 05/ 8 9 TO 05/89 1990-05-28 37 16. SUPPLEMENTARY NOTATION Submitted to Journal of Electroanalytical ... Chemistry 17 COSATI CODES 18 SUBJECT TERMS (Continue on riverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Pyridine adsorption

  2. Adsorption of Pyridine at the Au(311) - Solution Interface

    Science.gov (United States)

    1991-02-15

    Solution Interface by L. Stolberg, J. Lipkowski, and D.E. Irish Prepared for Publication in Journal of Electroanalytical Chemistry Guelph-Waterloo...REPORT (Year, Month,ODay) iSPAGE COUNTITechnical T1FRO 89 T0729071 1990-02-5I 3 16. SUPPLEMENTARY NOTATION Submitted to Journal of Electroanalytical ... Chemistry 17 COSATI CODES 1S SUBjECT TERMIS (Continue on reverse of necessary and identify by block number) FIELD GROUP SUB-GROUP Pyridine adsorption on Au

  3. 1-[Phenyl(pyridin-2-ylaminomethyl]-2-naphthol

    Directory of Open Access Journals (Sweden)

    Jie Xiao

    2010-11-01

    Full Text Available The title compound, C22H18N2O, was synthesized from naphthalen-2-ol, benzaldehyde and pyridin-2-amine. In the crystal, molecules are linked into centrosymmetric R22(16 dimers by pairs of O—H...N hydrogen bonds. The molecular conformation is stabilized by an N—H...O hydrogen bond. The dihedral angle between the naphthylene ring system and the phenyl ring is 72.86 (12°.

  4. Pyridine metabolism in tea plants: salvage, conjugate formation and catabolism.

    Science.gov (United States)

    Ashihara, Hiroshi; Deng, Wei-Wei

    2012-11-01

    Pyridine compounds, including nicotinic acid and nicotinamide, are key metabolites of both the salvage pathway for NAD and the biosynthesis of related secondary compounds. We examined the in situ metabolic fate of [carbonyl-(14)C]nicotinamide, [2-(14)C]nicotinic acid and [carboxyl-(14)C]nicotinic acid riboside in tissue segments of tea (Camellia sinensis) plants, and determined the activity of enzymes involved in pyridine metabolism in protein extracts from young tea leaves. Exogenously supplied (14)C-labelled nicotinamide was readily converted to nicotinic acid, and some nicotinic acid was salvaged to nicotinic acid mononucleotide and then utilized for the synthesis of NAD and NADP. The nicotinic acid riboside salvage pathway discovered recently in mungbean cotyledons is also operative in tea leaves. Nicotinic acid was converted to nicotinic acid N-glucoside, but not to trigonelline (N-methylnicotinic acid), in any part of tea seedlings. Active catabolism of nicotinic acid was observed in tea leaves. The fate of [2-(14)C]nicotinic acid indicates that glutaric acid is a major catabolite of nicotinic acid; it was further metabolised, and carbon atoms were finally released as CO(2). The catabolic pathway observed in tea leaves appears to start with the nicotinic acid N-glucoside formation; this pathway differs from catabolic pathways observed in microorganisms. Profiles of pyridine metabolism in tea plants are discussed.

  5. Anticancer efficacy of unique pyridine-based tetraindoles.

    Science.gov (United States)

    Fu, Chih-Wei; Hsieh, Yun-Jung; Chang, Tzu Ting; Chen, Chia-Ling; Yang, Cheng-Yu; Liao, Anne; Hsiao, Pei-Wen; Li, Wen-Shan

    2015-11-02

    Results of previous studies demonstrated that the tetraindole, SK228, which has a high lipid but low water solubility, displayed moderate anticancer efficacy in a xenograft model of breast cancer. This finding led to the proposal that new, pyridine based tetraindole (PBT) analogs of SK228, containing tetraindole moieties distributed about central protonated pyridine cores, would have enhanced bioavailabilities and anticancer efficacies. Among the PBTs prepared and subjected to biological studies, 3f (FCW81) was observed to display the highest antiproliferative activity against the two triple negative breast cancer (TNBCs) cell lines, MDA-MB-231 and BT549. In addition, its mode of action was shown to involve G2/M arrest of the cell cycle along with the promotion of increased levels of cyclin B1 and p-chk2 and a decreased level of p-cdc2. DNA damage and induction of apoptosis caused by FCW81 was found to be associated with a decrease in DNA repair. Significantly, FCW81 displays therapeutic efficacy in a xenograft model of human breast cancer by not only serving to inhibit markedly the growth of cancer cells but also to block effectively cancer cell metastasis. Collectively, the results of these studies have led to the identification of novel pyridine-tetraindole based anticancer agents with potential use in TNBC therapy.

  6. The role of electron donors generated from UV photolysis for accelerating pyridine biodegradation.

    Science.gov (United States)

    Tang, Yingxia; Zhang, Yongming; Yan, Ning; Liu, Rui; Rittmann, Bruce E

    2015-09-01

    Employing an internal circulation baffled biofilm reactor (ICBBR), we evaluated the mechanisms by which photolysis accelerated the biodegradation and mineralization of pyridine (C5 H5 N), a nitrogen-containing heterocyclic compound. We tested the hypothesis that pyridine oxidation is accelerated because a key photolysis intermediate, succinate, is as electron donor that promotes the initial mono-oxygenation of pyridine. Experimentally, longer photolysis time generated more electron-donor products (succinate), which stimulated faster pyridine biodegradation. This pattern was confirmed by directly adding succinate, and the stimulation effect occurred similarly with addition of the same equivalents of acetate and formate. Succinate, whether generated by UV photolysis or added directly, also accelerated mono-oxygenation of the first biodegradation intermediate, 2-hydroxyl pyridine (2HP). 2HP and pyridine were mutually inhibitory in that their mono-oxygenations competed for internal electron donor; thus, the addition of any readily biodegradable donor accelerated both mono-oxygenation steps, as well as mineralization.

  7. A novel porphyrin-containing polyimide nanofibrous membrane for colorimetric and fluorometric detection of pyridine vapor.

    Science.gov (United States)

    Lv, Yuanyuan; Zhang, Yani; Du, Yanglong; Xu, Jiayao; Wang, Junbo

    2013-11-19

    A novel zinc porphyrin-containing polyimide (ZPCPI) nanofibrous membrane for rapid and reversible detection of trace amounts of pyridine vapor is described. The membrane displays a distinct color change, as well as dramatic variations in absorption and fluorescent emission spectra, upon exposure to pyridine vapor. This condition allows the detection of the analyte at concentrations as low as 0.041 ppm. The vapochromic and spectrophotometric responses of the membrane are attributed to the formation of the ZPCPI-pyridine complex upon axial coordination. From surface plasmon resonance analysis, the affinity constant of ZPCPI-pyridine complex was calculated to be (3.98 ± 0.25) × 104 L · mol(-1). The ZPCPI nanofibrous membrane also showed excellent selectivity for pyridine vapor over other common amines, confirming its applicability in the manufacture of pyridine-sensitive gas sensors.

  8. Correlation between the Standard Formation Enth alpy and the Path Index of Pyridine-Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A formulated as △ H (PDDs ,g)=a+ ∑ biPi+ ∑ cifi is put forward for estimating standard formation enthalpies of pyridine-derivatives (PDDs),in which ,Pi is path index and cifi is an amended term of interaction between substituent and N atom on pyridine ring. The Calculations based on the model were carried out for some pyridine-derivatives. The values of standard formation enthalpy calculated are consistent with those in literature

  9. Synthesis of a New Aromatic Dianhydride Containing Pyridine Ring and Related Polyimide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new aromatic dianhydride monomer containing pyridine moiety, 2,6-bis[4'-(3",4"dicarboxyphenoxy)benzoyl]-pyridine dianhydride (Md), was synthesized in four steps, starting from 2,6-pyridinedicarboxyl chloride. A novel pyridine-containing polyimide was prepared via polycondensation of Md with ODA by two-step method. The resulting polyimide exhibits excellent solubility, film-forming capability and high thermal resistance.

  10. Highly stable supramolecular hydrogels formed from 1,3,5-benzenetricarboxylic acid and hydroxyl pyridines

    Institute of Scientific and Technical Information of China (English)

    Li Ming Tang; Yu Jiang Wang

    2009-01-01

    New supramolecular hydrogels with the maximal sol-gel transition temperature (T_(gel)) of 95 ℃ were obtained by using gelators formed from 1,3,5-benzenetricarboxylic acid (BTA) and para-hydroxyl pyridine (PHP) or meta-hydroxyl pyridine (MHP). The single crystal structure of the complex formed from BTA and ortho-hydroxyl pyridine (OHP) indicated that the molecules assembled into superstructure via both hydrogen bonds and π-π stacking interaction.

  11. Synthesis of a new pyridine-containing diamine and related polyimide

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new kind of aromatic diamine monomer containing pyridine unit,2,6-bis[4-(4-aminophenoxy)phenoxy]pyridine(BAPP),was synthesized in three steps,using hydroquinone as starting material.A novel pyridine-containing polyimide was prepared from the resulting diamine BAPP with 4,4'-oxydiphthalic anhydride(ODPA) via a conventional two-step thermal imidization method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.

  12. Structural rearrangements and magic numbers in reactions between pyridine-containing water clusters and ammonia.

    Science.gov (United States)

    Ryding, Mauritz J; Ruusuvuori, Kai; Andersson, Patrik U; Zatula, Alexey S; McGrath, Matthew J; Kurtén, Theo; Ortega, Ismael K; Vehkamäki, Hanna; Uggerud, Einar

    2012-05-24

    Molecular cluster ions H(+)(H(2)O)(n), H(+)(pyridine)(H(2)O)(n), H(+)(pyridine)(2)(H(2)O)(n), and H(+)(NH(3))(pyridine)(H(2)O)(n) (n = 16-27) and their reactions with ammonia have been studied experimentally using a quadrupole-time-of-flight mass spectrometer. Abundance spectra, evaporation spectra, and reaction branching ratios display magic numbers for H(+)(NH(3))(pyridine)(H(2)O)(n) and H(+)(NH(3))(pyridine)(2)(H(2)O)(n) at n = 18, 20, and 27. The reactions between H(+)(pyridine)(m)(H(2)O)(n) and ammonia all seem to involve intracluster proton transfer to ammonia, thus giving clusters of high stability as evident from the loss of several water molecules from the reacting cluster. The pattern of the observed magic numbers suggest that H(+)(NH(3))(pyridine)(H(2)O)(n) have structures consisting of a NH(4)(+)(H(2)O)(n) core with the pyridine molecule hydrogen-bonded to the surface of the core. This is consistent with the results of high-level ab initio calculations of small protonated pyridine/ammonia/water clusters.

  13. Influence of supramolecular structures in crystals on parallel stacking interactions between pyridine molecules.

    Science.gov (United States)

    Janjić, Goran V; Ninković, Dragan B; Zarić, Snezana D

    2013-08-01

    Parallel stacking interactions between pyridines in crystal structures and the influence of hydrogen bonding and supramolecular structures in crystals on the geometries of interactions were studied by analyzing data from the Cambridge Structural Database (CSD). In the CSD 66 contacts of pyridines have a parallel orientation of molecules and most of these pyridines simultaneously form hydrogen bonds (44 contacts). The geometries of stacked pyridines observed in crystal structures were compared with the geometries obtained by calculations and explained by supramolecular structures in crystals. The results show that the mean perpendicular distance (R) between pyridine rings with (3.48 Å) and without hydrogen bonds (3.62 Å) is larger than that calculated, because of the influence of supramolecular structures in crystals. The pyridines with hydrogen bonds show a pronounced preference for offsets of 1.25-1.75 Å, close to the position of the calculated minimum (1.80 Å). However, stacking interactions of pyridines without hydrogen bonds do not adopt values at or close to that of the calculated offset. This is because stacking interactions of pyridines without hydrogen bonds are less strong, and they are more susceptible to the influence of supramolecular structures in crystals. These results show that hydrogen bonding and supramolecular structures have an important influence on the geometries of stacked pyridines in crystals.

  14. Oxyfunctionalization of pyridine derivatives using whole cells of Burkholderia sp. MAK1

    Science.gov (United States)

    Stankevičiūtė, Jonita; Vaitekūnas, Justas; Petkevičius, Vytautas; Gasparavičiūtė, Renata; Tauraitė, Daiva; Meškys, Rolandas

    2016-01-01

    Pyridinols and pyridinamines are important intermediates with many applications in chemical industry. The pyridine derivatives are in great demand as synthons for pharmaceutical products. Moreover, pyridines are used either as biologically active substances or as building blocks for polymers with unique physical properties. Application of enzymes or whole cells is an attractive strategy for preparation of hydroxylated pyridines since the methods for chemical synthesis of pyridinols, particularly aminopyridinols, are usually limited or inefficient. Burkholderia sp. MAK1 (DSM102049), capable of using pyridin-2-ol as the sole carbon and energy source, was isolated from soil. Whole cells of Burkholderia sp. MAK1 were confirmed to possess a good ability to convert different pyridin-2-amines and pyridin-2-ones into their 5-hydroxy derivatives. Moreover, several methylpyridines as well as methylated pyrazines were converted to appropriate N-oxides. In conclusion, regioselective oxyfunctionalization of pyridine derivatives using whole cells of Burkholderia sp. MAK1 is a promising method for the preparation of various pyridin-5-ols and pyridin-N-oxides. PMID:27982075

  15. Structure of Fullerene Aggregates in Pyridine/Water Solutions by Small-Angle Neutron Scattering

    CERN Document Server

    Aksenov, V L; Belushkin, A V; Mihailovic, D; Mrzel, A; Rosta, L; Serdyuk, I N; Timchenko, A A

    2001-01-01

    Results of small-angle neutron scattering experiments on fullerenes (Co_{60}) in pyridine/water solutions are reported. They confirm conclusions of the previous studies, in particular, dynamic light scattering experiments. Aggregates with characteristic radius of about 20 nm are formed in the solutions. The contrast variation using different combinations of protonated/deuterated components (water and pyridine) of the solutions points to the small pyridine content inside the aggregates. This fact testifies that the aggregates consist of a massive fullerene core covered by a thin pyridine shell.

  16. Exo conformers of N-(pyridin-2-yl)- and N-(pyridin-3-yl)norbornene-5,6-dicarboximide crystals.

    Science.gov (United States)

    Vazquez-Vuelvas, Oscar F; Hernández-Madrigal, Julia V; Pineda-Contreras, Armando; Hernández-Ortega, Simón; Reyes-Martínez, Reyna; Morales-Morales, David

    2015-03-01

    Two isomeric pyridine-substituted norbornenedicarboximide derivatives, namely N-(pyridin-2-yl)-exo-norbornene-5,6-dicarboximide, (I), and N-(pyridin-3-yl)-exo-norbornene-5,6-dicarboximide, (II), both C(14)H(12)N(2)O(4), have been crystallized and their structures unequivocally determined by single-crystal X-ray diffraction. The molecules consist of norbornene moieties fused to a dicarboximide ring substituted at the N atom by either pyridin-2-yl or pyridin-3-yl in an anti configuration with respect to the double bond, thus affording exo isomers. In both compounds, the asymmetric unit consists of two independent molecules (Z' = 2). In compound (I), the pyridine rings of the two independent molecules adopt different conformations, i.e. syn and anti, with respect to the methylene bridge. The intermolecular contacts of (I) are dominated by C-H...O interactions. In contrast, in compound (II), the pyridine rings of both molecules have an anti conformation and the two independent molecules are linked by carbonyl-carbonyl interactions, as well as by C-H...O and C-H...N contacts.

  17. In search of oligo(2-thienyl)-substituted pyridine derivatives: a modular approach to di-, tri- and tetra(2-thienyl)pyridines.

    Science.gov (United States)

    Bera, Mrinal K; Hommes, Paul; Reissig, Hans-Ulrich

    2011-10-10

    Herein, we describe our attempts to systematically prepare a series of oligo(2-thienyl)-substituted pyridine derivatives. The crucial starting material, a β-alkoxy-β-ketoenamide, is easily available on a large scale by the reaction of lithiated methoxyallene with thiophene-2-carbonitrile and thiophene-2-carboxylic acid. This three-component reaction is followed by intramolecular cyclization to yield the suitably functionalized 2,6-di(2-thienyl)-substituted pyridine derivates. The two oxygen atoms allow the programmed activation of positions C-3, C-4, or C-5 of the pyridine ring to perform palladium-catalyzed coupling reactions with thiophene-2-boronic acid or 2-(tributylstannyl)thiophene, and alternatively, reductive removal of groups. With this concept, we were able to prepare five pyridine derivatives with 2-thienyl substituents in the 2,6-, 2,3,6-, 2,4,6-, 2,3,4,6-, and 2,3,5,6-positions. 2,3,4,5,6-Penta(2-thienyl)pyridine was not available with our methods. The UV/Vis and fluorescence spectra of all pyridines were recorded and showed a dependence on the substitution pattern and protonation state. For the protonated 2,3,5,6-tetra(2-thienyl)-substituted pyridine, a Stokes shift of about 180 nm with an emission at 515 nm was observed.

  18. Etude aerodynamique d'un jet turbulent impactant une paroi concave

    Science.gov (United States)

    LeBlanc, Benoit

    Etant donne la demande croissante de temperatures elevees dans des chambres de combustion de systemes de propulsions en aerospatiale (turbomoteurs, moteur a reaction, etc.), l'interet dans le refroidissement par jets impactant s'est vu croitre. Le refroidissement des aubes de turbine permet une augmentation de temperature de combustion, ce qui se traduit en une augmentation de l'efficacite de combustion et donc une meilleure economie de carburant. Le transfert de chaleur dans les au bages est influence par les aspects aerodynamiques du refroidissement a jet, particulierement dans le cas d'ecoulements turbulents. Un manque de comprehension de l'aerodynamique a l'interieur de ces espaces confinees peut mener a des changements de transfert thermique qui sont inattendus, ce qui augmente le risque de fluage. Il est donc d'interet pour l'industrie aerospatiale et l'academie de poursuivre la recherche dans l'aerodynamique des jets turbulents impactant les parois courbes. Les jets impactant les surfaces courbes ont deja fait l'objet de nombreuses etudes. Par contre des conditions oscillatoires observees en laboratoire se sont averees difficiles a reproduire en numerique, puisque les structures d'ecoulements impactants des parois concaves sont fortement dependantes de la turbulence et des effets instationnaires. Une etude experimentale fut realisee a l'institut PPRIME a l'Universite de Poitiers afin d'observer le phenomene d'oscillation dans le jet. Une serie d'essais ont verifie les conditions d'ecoulement laminaires et turbulentes, toutefois le cout des essais experimentaux a seulement permis d'avoir un apercu du phenomene global. Une deuxieme serie d'essais fut realisee numeriquement a l'Universite de Moncton avec l'outil OpenFOAM pour des conditions d'ecoulement laminaire et bidimensionnel. Cette etude a donc comme but de poursuivre l'enquete de l'aerodynamique oscillatoire des jets impactant des parois courbes, mais pour un regime d'ecoulement transitoire, turbulent

  19. Unconventional hydrogen bonding to organic ions in the gas phase: stepwise association of hydrogen cyanide with the pyridine and pyrimidine radical cations and protonated pyridine.

    Science.gov (United States)

    Hamid, Ahmed M; El-Shall, M Samy; Hilal, Rifaat; Elroby, Shaaban; Aziz, Saadullah G

    2014-08-07

    Equilibrium thermochemical measurements using the ion mobility drift cell technique have been utilized to investigate the binding energies and entropy changes for the stepwise association of HCN molecules with the pyridine and pyrimidine radical cations forming the C5H5N(+·)(HCN)n and C4H4N2 (+·)(HCN)n clusters, respectively, with n = 1-4. For comparison, the binding of 1-4 HCN molecules to the protonated pyridine C5H5NH(+)(HCN)n has also been investigated. The binding energies of HCN to the pyridine and pyrimidine radical cations are nearly equal (11.4 and 12.0 kcal/mol, respectively) but weaker than the HCN binding to the protonated pyridine (14.0 kcal/mol). The pyridine and pyrimidine radical cations form unconventional carbon-based ionic hydrogen bonds with HCN (CH(δ+)⋯NCH). Protonated pyridine forms a stronger ionic hydrogen bond with HCN (NH(+)⋯NCH) which can be extended to a linear chain with the clustering of additional HCN molecules (NH(+)⋯NCH··NCH⋯NCH) leading to a rapid decrease in the bond strength as the length of the chain increases. The lowest energy structures of the pyridine and pyrimidine radical cation clusters containing 3-4 HCN molecules show a strong tendency for the internal solvation of the radical cation by the HCN molecules where bifurcated structures involving multiple hydrogen bonding sites with the ring hydrogen atoms are formed. The unconventional H-bonds (CH(δ+)⋯NCH) formed between the pyridine or the pyrimidine radical cations and HCN molecules (11-12 kcal/mol) are stronger than the similar (CH(δ+)⋯NCH) bonds formed between the benzene radical cation and HCN molecules (9 kcal/mol) indicating that the CH(δ+) centers in the pyridine and pyrimidine radical cations have more effective charges than in the benzene radical cation.

  20. In vitro study on the interaction of ketotifen fumarate with anhydrous theophylline

    Directory of Open Access Journals (Sweden)

    Mohammed Aktar Sayeed

    2012-06-01

    Full Text Available The purpose of the present study was to investigate the interaction between ketotifen fumarate and anhydrous theophylline in aqueous media of various pH (1.2 and 6.8. Using Job's continuous-variation analysis and Ardon's spectrophotomeric measurement methods, the values of the stability constants of theophylline with ketotifen were determined at a fixed temperature (37 ºC at various pH. The stability constants, ranging between 5.66 and 9.92, were derived from Ardon's plot, indicating that comparatively stable complexes had formed as a result of an interaction between the drugs. However, following the interaction of theophylline with ketotifen, stability constants were O objetivo do presente estudo foi investigar a interação entre o fumarato de cetotifeno e a teofilina anidra em meios aquosos com vários pH (1,2 e 6,8. Utilizando a análise da variação contínua de Job e os métodos de medida espectrofotométrica de Ardon, os valores das constantes de estabilidade da teofilina com o cetotifeno foram determinados em temperatura fixa (37 oC em vários pH. As constantes de estabilidade, variando entre 5,66 e 9,92 derivaram-se a partir do delineamento de Ardon, indicando, comparativamente, que complexos estáveis se formaram como resultado da interação entre os fármacos. Entretanto, seguindo a interação da teofilina com o cetotifeno, as constantes de estabilidade foram <1, em pH gástrico (1,2 e intestinal (8,8. A administração concomitante de cetotifeno e teofilina poderia resultar na formação de complexo estável, o que reduz a atividade terapêutica de ambos os fármacos.

  1. Special topical approach to the treatment of acne. Suppression of sweating with aluminum chloride in an anhydrous formulation.

    Science.gov (United States)

    Hurley, H J; Shelley, W B

    1978-12-01

    A new topical approach to acne treatment--the use of aluminum chloride hexahydrate in anhydrous ethanol (ACAE)--was studied in 141 patients. Using sequential treatment schedules, paired comparison techniques, and various concentrations of ACAE, we established maximal efficacy with minimal local irritation for the 6.25% strength solution. Clinical efficacy and lack of toxicity of this formulation were confirmed by the additional clinical study of 65 patients. The antiperspirant and antibacterial actions of 6.25% ACAE solution were then verified on acne skin areas. It is postulated that the clinical improvement in acne that follows the topical use of ACAE results from one or both of these actions.

  2. A Safe and Brief Way for Preparing Anhydrous LnCl3 (Ln=Sc, Y, La to Lu)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Anhydrous lanthanide chlorides LnCl3 (Ln=Sc, Y, La to Lu except for Pm), which are difficult to prepare in other ways, were prepared by chemical vapor transport (CVT) process. Rare earth oxide reacted with Al2Cl6 at 300℃ to produce LnCl3, which was then separated from other solids by means of CVT at a temperature gradient from 400 to 180℃. Residual Al2Cl6 (g) was removed by carrier of dry N2 gas at 200℃. The yielding rates were >90%, and the purity of products was >99.5%.

  3. Improved quantification of alite and belite in anhydrous Portland cements by 29Si MAS NMR: Effects of paramagnetic ions

    DEFF Research Database (Denmark)

    Poulsen, Søren Lundsted; Kocaba, Vanessa; Le Saoût, Gwenn;

    2009-01-01

    The applicability, reliability, and repeatability of 29Si MAS NMR for determination of the quantities of alite (Ca3SiO5) and belite (Ca2SiO4) in anhydrous Portland cement was investigated in detail for 11 commercial Portland cements and the results compared with phase quantifications based...... on powder X-ray diffraction combined with Rietveld analysis and with Taylor-Bogue calculations. The effects from paramagnetic ions (Fe3+) on the spinning sideband intensities, originating from dipolar couplings between 29Si and the spins of the paramagnetic electrons, were considered and analyzed in spectra...

  4. Pyridine alkaloids from Senna multijuga as acetylcholinesterase inhibitors.

    Science.gov (United States)

    Francisco, Welington; Pivatto, Marcos; Danuello, Amanda; Regasini, Luis O; Baccini, Luciene R; Young, Maria C M; Lopes, Norberto P; Lopes, João L C; Bolzani, Vanderlan S

    2012-03-23

    As part of an ongoing research project on Senna and Cassia species, five new pyridine alkaloids, namely, 12'-hydroxy-7'-multijuguinol (1), 12'-hydroxy-8'-multijuguinol (2), methyl multijuguinate (3), 7'-multijuguinol (4), and 8'-multijuguinol (5), were isolated from the leaves of Senna multijuga (syn. Cassiamultijuga). Their structures were elucidated on the basis of spectroscopic data analysis. Mass spectrometry was used for confirmation of the positions of the hydroxy groups in the side-chains of 1, 2, 4, and 5. All compounds exhibited weak in vitro acetylcholinesterase inhibitory activity as compared with the standard compound physostigmine.

  5. Bis(pyridine-2-carbaldehyde thiosemicarbazonezinc(II dinitrate dihydrate

    Directory of Open Access Journals (Sweden)

    Jian-Quan Wang

    2010-10-01

    Full Text Available The asymmetric unit of the title compound, [Zn(C7H8N4S2](NO32·2H2O, contains two Zn(pht2 cations (pht is pyridine-2-carbaldehyde thiosemicarbazone, four nitrate anions and four water molecules. In the cations, each ZnII ion adopts a distorted octahedral coordination geometry, being chelated by two tridentate pht ligands. In the crystal, the cations, anions and water molecules are connected via O—H...O and N—H...O hydrogen bonds into a three-dimensional network.

  6. HALOMETHYLATION OF POLYSTYRENE AND SUBSEQUENT PYRIDINATION VIA A HOMOLYTIC PATHWAY

    Institute of Scientific and Technical Information of China (English)

    Sa(a)d Moulay; Nadia Mehdi

    2006-01-01

    Chloromethylation of polystyrene (PS) with two different chloromethylating systems methylal/thionyl chloride and paraformaldehyde/trimethylchlorosilane was studied. Soluble chloromethylated polystyrene with a degree of substitution of 89% was obtained. The Conant-Finkelstein reaction on the chloromethylated PS afforded soluble iodomethylated polystyrene with a degree of substitution as high as 96%. The reaction conditions of Minisci were employed to radically pyridinate PS via its iodomethylated derivative. Polyelectrolytes were formed which could be converted to normal polymers by treatment with a 20% aqueous solution of NaOH.

  7. Pyridine-2,6-dicarboxaldehyde bis[(diphenylmethylidenehydrazone

    Directory of Open Access Journals (Sweden)

    Florina Dumitru

    2011-05-01

    Full Text Available The title compound, C33H25N5, belongs to the family of pyridine-2,6-dicarboxaldehyde Schiff bases which possess a terdentate coordinating site (–N=C–C=N–C–C=N– similar to terpyridine derivatives. The dihedral angles between pairs of terminal rings are 69.67 (9 and 66.23 (9°. The shortest distance between the centroids of aromatic rings in neighbouring molecules is 3.8080 (14 Å.

  8. 3-(Pyridin-4-ylthiopentane-2,4-dione

    Directory of Open Access Journals (Sweden)

    Qing-Fu Zhang

    2011-04-01

    Full Text Available In the title compound, C10H11NO2S, the acetylacetone group crystallizes in the keto form with all the non-hydrogen atoms in the acetylacetone group approximately co-planar with a maximum atomic deviation 0.055 (2 Å; the dihedral angle between the acetylacetone group and the pyridine ring is 85.90 (6°. An intramolecular O—H...O hydrogen bond involving the acetylacetone group forms a six-membered ring.

  9. Separation of rare earth elements by tertiary pyridine type resin

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Tatsuya [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)]. E-mail: tasuzuki@nr.titech.ac.jp; Itoh, Keisuke [Graduate School of Material Science and Engineering, Shibaura Institute of Technology, Shibaura, Minato-ku, Tokyo 108-8584 (Japan); Ikeda, Atsushi [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Aida, Masao [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Ozawa, Masaki [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Oarai Engineering Center, Japan Nuclear Cycle Development Institute, Narita-machi, Oarai-machi, Higashiibaraki-gun, Ibaraki 311-1393 (Japan); Fujii, Yasuhiko [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2006-02-09

    The novel separation method of rare earth elements by using the tertiary pyridine type resin with methanol and nitric acid mixed solution was developed. The separating operation in this method is very simple and easy, and the waste generation in this method is expected to be low. The adsorption and separation behaviors of rare earth elements were investigated with changing the nitric acid concentration, the methanol concentration, and the alcoholic species. It was confirmed that the rare earth elements can be well separated mutually.

  10. Aquabis(methacrylato-κObis(pyridine-κNcopper(II

    Directory of Open Access Journals (Sweden)

    Bin Wu

    2009-05-01

    Full Text Available In the crystal structure of the title complex, [Cu(C4H5O22(C5H5N2(H2O], the CuII cation is located on a twofold rotation axis and coordinated by two methylacrylate anions, two pyridine ligands and one water molecule in a distorted square-pyramidal geometry. The coordinated water molecule is also located on the twofold axis. In the crystal structure O—H...O hydrogen bonds link the molecules, forming chains along the c axis.

  11. Pyridine radical cation and its fluorine substituted derivatives

    Science.gov (United States)

    Bondybey, V.E.; English, J.H.; Shiley, R.H.

    1982-01-01

    The spectra and relaxation of the pyridine cation and of several of its fluorinated derivatives are studied in low temperature Ne matrices. The ions are generated by direct photoionization of the parent compounds. Of the compounds studied, laser induced → and → fluorescence is observed only for the 2, 6‐difluoropyridine cation. The analysis of the spectrum indicates that the ion is planar both in the and states. The large variety in the spectroscopic and relaxation behavior of fluoropyridine radical cations is explained in terms of their electronic structure and of the differential shifts of the individual electronic states caused by the fluorine substitution.

  12. (E-2-(4-Chlorophenoxy-N′-(pyridin-4-ylmethylideneacetohydrazide

    Directory of Open Access Journals (Sweden)

    Xiao-jin Rao

    2013-01-01

    Full Text Available In the title compound, C14H12ClN3O2, the acylhydrazone base [C(=O—N—N=C] is essentially planar, with an r.m.s. deviation of 0.0095 Å, and makes a dihedral angle of 12.52 (10°with the pyridine ring. In the crystal, molecules are linked via pairs of N—H...O hydrogen bonds, forming inversion dimers with an R22(8 graph-set motif. The dimers are linked via C—H...π interactions forming chains along [101].

  13. Methods for the synthesis of deuterated vinyl pyridine monomers

    Science.gov (United States)

    Hong, Kunlun; Yang, Jun; Bonnesen, Peter V

    2014-02-25

    Methods for synthesizing deuterated vinylpyridine compounds of the Formula (1), wherein the method includes: (i) deuterating an acyl pyridine of the Formula (2) in the presence of a metal catalyst and D.sub.2O, wherein the metal catalyst is active for hydrogen exchange in water, to produce a deuterated acyl compound of Formula (3); (ii) reducing the compound of Formula (3) with a deuterated reducing agent to convert the acyl group to an alcohol group, and (iii) dehydrating the compound produced in step (ii) with a dehydrating agent to afford the vinylpyridine compound of Formula (1). The resulting deuterated vinylpyridine compounds are also described.

  14. Research on the degradation mechanism of pyridine in drinking water by dielectric barrier discharge.

    Science.gov (United States)

    Li, Yang; Yi, Rongjie; Yi, Chengwu; Zhou, Biyun; Wang, Huijuan

    2017-03-01

    Pyridine, an important chemical raw material, is widely used in industry, for example in textiles, leather, printing, dyeing, etc. In this research, a dielectric barrier discharge (DBD) system was developed to remove pyridine, as a representative type of nitrogen heterocyclic compound in drinking water. First, the influence of the active species inhibitors tertiary butanol alcohol (TBA), HCO3(-), and CO3(2-) on the degradation rate of pyridine was investigated to verify the existence of active species produced by the strong ionization discharge in the system. The intermediate and final products generated in the degradation process of pyridine were confirmed and analyzed through a series of analytical techniques, including liquid chromatography-mass spectrometry (LC-MS), high performance liquid chromatography (HPLC), ion chromatography (IC), total organic carbon (TOC) analysis, ultraviolet (UV) spectroscopy, etc. The results showed that the degradation of pyridine was mainly due to the strong oxidizing power of ozone and hydroxyl radical produced by the DBD system. Several intermediate products including 3-hydroxyl pyridine, fumaric acid, 2, 3-dihydroxypyridine, and oxalic acid were detected. Nitrogen was removed from the pyridine molecule to form nitrate. Through analysis of the degradation mechanism of pyridine, the oxidation pathway was deduced. The study provided a theoretical and experimental basis for the application of DBD strong ionization discharge in treatment of nitrogen heterocyclic compounds in drinking water. Copyright © 2016. Published by Elsevier B.V.

  15. 4-[3-(Pyridin-3-ylprop-2-enoyl]phenyl 4-dodecyloxybenzoate

    Directory of Open Access Journals (Sweden)

    Sie-Tiong Ha

    2015-12-01

    Full Text Available Steglich esterification between 1-(4-hydroxyphenyl-3-(pyridin-3-ylprop-2-en-1-one and 4-dodecyloxybenzoic acid has produced a new compound, 4-[3-(pyridin-3-yl prop-2-enoyl]phenyl 4-dodecyloxybenzoate. The title compound was characterized by IR and NMR analysis.

  16. Novel Amino-Pyridine Functionalized Chitosan Quaternary Ammonium Derivatives: Design, Synthesis, and Antioxidant Activity.

    Science.gov (United States)

    Li, Qing; Zhang, Caili; Tan, Wenqiang; Gu, Guodong; Guo, Zhanyong

    2017-01-18

    Chemical modification of chitosan is increasingly studied for its potential of providing new applications of chitosan. Here, a group of novel chitosan quaternary ammonium derivatives containing pyridine or amino-pyridine were designed and successfully synthesized through chemical modification of chitosan. Pyridine and amino-pyridine were used as functional groups to improve the antifungal activity of chitosan derivatives. The chitosan derivatives' antioxidant activity against hydroxyl-radical and 1,1-Diphenyl-2-picrylhydrazyl (DPPH)-radical was tested in vitro. The results showed that chitosan derivatives had better water solubility and stronger antioxidant activity compared with chitosan in all assays. Especially, compounds 3C and 3E (with 3-amino pyridine and 2,3-diamino pyridine as substitute respectively) exhibited stronger hydroxyl-radical and DPPH-radical scavenging ability than other synthesized compounds. These data demonstrated that the synergistic effect of the amino group and pyridine would improve the antioxidant activity of chitosan derivatives, and the position of the amino group on pyridine could influence the antioxidant property of chitosan derivatives.

  17. Novel Amino-Pyridine Functionalized Chitosan Quaternary Ammonium Derivatives: Design, Synthesis, and Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Qing Li

    2017-01-01

    Full Text Available Chemical modification of chitosan is increasingly studied for its potential of providing new applications of chitosan. Here, a group of novel chitosan quaternary ammonium derivatives containing pyridine or amino-pyridine were designed and successfully synthesized through chemical modification of chitosan. Pyridine and amino-pyridine were used as functional groups to improve the antifungal activity of chitosan derivatives. The chitosan derivatives’ antioxidant activity against hydroxyl-radical and 1,1-Diphenyl-2-picrylhydrazyl (DPPH-radical was tested in vitro. The results showed that chitosan derivatives had better water solubility and stronger antioxidant activity compared with chitosan in all assays. Especially, compounds 3C and 3E (with 3-amino pyridine and 2,3-diamino pyridine as substitute respectively exhibited stronger hydroxyl-radical and DPPH-radical scavenging ability than other synthesized compounds. These data demonstrated that the synergistic effect of the amino group and pyridine would improve the antioxidant activity of chitosan derivatives, and the position of the amino group on pyridine could influence the antioxidant property of chitosan derivatives.

  18. Removal of pyridine from liquid and gas phase by copper forms of natural and synthetic zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Rehakova, Maria, E-mail: maria.rehakova@upjs.sk [Institute of Chemistry, Faculty of Science, P.J. Safarik University, 041 54 Kosice (Slovakia); Fortunova, Lubica [Institute of Chemistry, Faculty of Science, P.J. Safarik University, 041 54 Kosice (Slovakia); Bastl, Zdenek [J. Heyrovsky Institute of Physical Chemistry, ASCR, v.v.i., 18223 Prague 8 (Czech Republic); Nagyova, Stanislava [Department of Physics, Electrotechnical Faculty, Technical University, 042 00 Kosice (Slovakia); Dolinska, Silvia [Institute of Geotechnics, Slovak Academy of Sciences, 043 53 Kosice (Slovakia); Jorik, Vladimir [Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 81237 Bratislava (Slovakia); Jona, Eugen [Department of Chemistry and Technology of Inorganic Materials, Faculty of Industrial Technologies, Trencin University of Alexander Dubcek, 02032 Puchov (Slovakia)

    2011-02-15

    Zeoadsorbents on the basis of copper forms of synthetic zeolite ZSM5 and natural zeolite of the clinoptilolite type (CT) have been studied taking into account their environmental application in removing harmful pyridine (py) from liquid and gas phase. Sorption of pyridine by copper forms of zeolites (Cu-ZSM5 and Cu-CT) has been studied by CHN, X-ray photoelectron spectroscopy, X-ray powder diffractometry, FTIR spectroscopy, thermal analysis (TG, DTA and DTG) and analysis of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. The results of thermal analyses of Cu-ZSM5, Cu-(py){sub x}ZSM5, Cu-CT and Cu-(py){sub x}CT zeolitic products with different composition (x depends on the experimental conditions of sorption of pyridine) clearly confirmed their different thermal properties as well as the sorption of pyridine. In the zeolitic pyridine containing samples the main part of the pyridine release process occurs at considerably higher temperatures than is the boiling point of pyridine, which proves strong bond and irreversibility of py-zeolite interaction. FTIR spectra of Cu-(py){sub x}zeolite samples showed well resolved bands of pyridine. The results of thermal analysis and FTIR spectroscopy are in a good agreement with the results of other used methods.

  19. Removal of pyridine from liquid and gas phase by copper forms of natural and synthetic zeolites.

    Science.gov (United States)

    Reháková, Mária; Fortunová, Lubica; Bastl, Zdeněk; Nagyová, Stanislava; Dolinská, Silvia; Jorík, Vladimír; Jóna, Eugen

    2011-02-15

    Zeoadsorbents on the basis of copper forms of synthetic zeolite ZSM5 and natural zeolite of the clinoptilolite type (CT) have been studied taking into account their environmental application in removing harmful pyridine (py) from liquid and gas phase. Sorption of pyridine by copper forms of zeolites (Cu-ZSM5 and Cu-CT) has been studied by CHN, X-ray photoelectron spectroscopy, X-ray powder diffractometry, FTIR spectroscopy, thermal analysis (TG, DTA and DTG) and analysis of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. The results of thermal analyses of Cu-ZSM5, Cu-(py)(x)ZSM5, Cu-CT and Cu-(py)(x)CT zeolitic products with different composition (x depends on the experimental conditions of sorption of pyridine) clearly confirmed their different thermal properties as well as the sorption of pyridine. In the zeolitic pyridine containing samples the main part of the pyridine release process occurs at considerably higher temperatures than is the boiling point of pyridine, which proves strong bond and irreversibility of py-zeolite interaction. FTIR spectra of Cu-(py)(x)zeolite samples showed well resolved bands of pyridine. The results of thermal analysis and FTIR spectroscopy are in a good agreement with the results of other used methods.

  20. Ab initio calculations on the structure of pyridine in its lowest triplet state

    NARCIS (Netherlands)

    Buma, W.J.; Groenen, E.J.J.; Schmidt, J.

    1990-01-01

    Recently we have experimentally shown that pyridine-d5, as a guest in a single crystal of benzene-d6, adopts a boatlike structure upon excitation into the lowest triplet state T0. Here MRDCI ab initio calculations are presented that reveal that the observed nonplanarity of the molecule is not caused

  1. Metal controlled regioselectivity in the cyclometallation of 2-(1-naphthyl)-pyridine.

    Science.gov (United States)

    Kondrashov, Mikhail; Raman, Sudarkodi; Wendt, Ola F

    2015-01-18

    Cyclometallation of 2-(1-naphthyl)-pyridine is described. While cyclopalladation results in a five-membered metallacycle, cycloauration displays a completely orthogonal regioselectivity, resulting in the six-membered ring analogue. Bromination of the gold metallacycle results in the new C-H functionalisation product 2-(8-bromonaphth-1-yl)pyridine.

  2. Unprecedentedly mild direct Pd-catalyzed arylation of oxazolo[4,5-b]pyridine

    DEFF Research Database (Denmark)

    Zhuravlev, Fedor

    2006-01-01

    Pd-catalyzed C-2 arylation of oxazolo[4,5-b]pyridine proceeds efficiently at 30 degrees C and tolerates a variety of aryl halides, including derivatized amino acids for which no racemization was observed during the reaction. Experimental evidence for facile deprotonation of oxazolo[4,5-b]pyridine...

  3. Liquid Crystalline Thiadiazole Derivatives: Thiadiazole Derivatives Containing Pyridine Ring as Terminal Group

    Institute of Scientific and Technical Information of China (English)

    XU,Yah(徐艳); XU,Yan; ZHU,Zhi-Guo(朱志国)XU; ZHU,Zhi-Guo; XU,Zheng(徐正); XU,Zheng

    2001-01-01

    The synthesis and mesomorphic behavior of a new series of liquid crystals coutaining 1,3,4-thiadiazole and pyridine rings with-CH = N-central group are reported. All compounds ex hibit enantiotropic snectic A mesophase, but the Schiff' s base analogues hnve no mesomorphic behavior. The innuence of the pyridine ing and thiadiazole ring is discussed.

  4. New Chiral Pyridine Prolinol Derivatives and Preliminary Study on Asymmetric Catalytic Reaction

    Institute of Scientific and Technical Information of China (English)

    Xiao CHEN; Yong Xin ZHANG; Da Ming DU; Wen Ting HUA

    2004-01-01

    Two new chiral pyridine prolinol derivatives have been synthesized from N-alkylation of (S)-α,α-diphenyl-2-pyrrolidinemethanol with 2-bromomethylpyridine and 2, 6-dibromo-methyl-pyridine. The catalytic asymmetric borane reduction of prochiral ketones and the asymmetric addition of diethylzinc to benzaldehyde were investigated.

  5. DFT analysis of the nucleophilicity of substituted pyridines and prediction of new molecules having nucleophilic character stronger than 4-pyrrolidino pyridine

    Indian Academy of Sciences (India)

    Kaustavmoni Deka; Prodeep Phukan

    2016-04-01

    Some commonly used 3-substituted, 4-substituted and 3,4,5-substituted pyridines were examined using DFT to predict the nucleophilicity behavior based on four different methods known in the literature. HOMO-LUMO energy calculations were done using DFT/B3LYP/6-311G+(d,p) level of theory. To establish the most suitable nucleophilicity scale for all the ranges of pyridines covered herein, either Hammett substituent constant () or experimental nucleophilicity values were computed. On the basis of this study, some new 4-substituted pyridines with enhanced nucleophilicity have been proposed. Nucleophilic behaviour of a few predicted molecules was found to be better than that of 4-pyrrolidino pyridine.

  6. Charting the Chemical Reactivity Space of 2,3-Substituted Furo[2,3-b]pyridines Synthesized via the Heterocyclization of Pyridine-N-oxide Derivatives.

    Science.gov (United States)

    Fumagalli, Fernando; da Silva Emery, Flavio

    2016-11-04

    A concise strategy for the synthesis of 2,3-substituted furo[2,3-b]pyridines is described. Mild, metal-free conditions were successfully applied to produce a range of 2-(alkyl or aryl)-3-ethylcarboxylate-furo[2,3-b]pyridines in yields of 50-91%. Then, the chemical reactivity of this heterocyclic framework was explored to develop straightforward methods for its functionalization. The pyridine moiety reactivity was successfully explored by C-H amination and borylation reactions, although C-H fluorination and radical C-H arylation processes were not as efficient. In addition, while the furopyridine core proved stable under basic conditions, the ring-opening reaction of the furan moiety with hydrazine generated a valuable new pyridine-dihydropyrazolone scaffold.

  7. Ionic-liquid-based proton conducting membranes for anhydrous H2/Cl2 fuel-cell applications.

    Science.gov (United States)

    Liu, Sa; Zhou, Li; Wang, Pengjie; Zhang, Fangfang; Yu, Shuchun; Shao, Zhigang; Yi, Baolian

    2014-03-12

    An ionic-liquid-doped poly(benzimidazole) (PBI) proton-conducting membrane for an anhydrous H2/Cl2 fuel cell has been proposed. Compared with other ionic liquids, such as imidazole-type ionic liquids, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) showed better electrode reaction kinetics (H2 oxidation and Cl2 reduction reaction at platinum) and was more suitable for a H2/Cl2 fuel cell. PBI polymer and [dema][TfO] were compatible with each other, and the hybrid membranes exhibited high stability and good ionic conductivity, reaching 20.73 mS cm(-1) at 160 °C. We also analyzed the proton-transfer mechanism in this ionic-liquid-based membrane and considered that both proton-hopping and diffusion mechanisms existed. In addition, this composite electrolyte worked well in a H2/Cl2 fuel cell under non-water conditions. This work would give a good path to study the novel membranes for anhydrous H2/Cl2 fuel-cell application.

  8. Measurement of bonding energy in an anhydrous nitrogen atmosphere and its application to silicon direct bonding technology

    Science.gov (United States)

    Fournel, F.; Continni, L.; Morales, C.; Da Fonseca, J.; Moriceau, H.; Rieutord, F.; Barthelemy, A.; Radu, I.

    2012-05-01

    Bonding energy represents an important parameter for direct bonding applications as well as for the elaboration of physical mechanisms at bonding interfaces. Measurement of bonding energy using double cantilever beam (DCB) under prescribed displacement is the most used technique thanks to its simplicity. The measurements are typically done in standard atmosphere with relative humidity above 30%. Therefore, the obtained bonding energies are strongly impacted by the water stress corrosion at the bonding interfaces. This paper presents measurements of bonding energies of directly bonded silicon wafers under anhydrous nitrogen conditions in order to prevent the water stress corrosion effect. It is shown that the measurements under anhydrous nitrogen conditions (less than 0.2 ppm of water in nitrogen) lead to high stable debonding lengths under static load and to higher bonding energies compared to the values measured under standard ambient conditions. Moreover, the bonding energies of Si/SiO2 or SiO2/SiO2 bonding interfaces are measured overall the classical post bond annealing temperature range. These new results allow to revisit the reported bonding mechanisms and to highlight physical and chemical phenomena in the absence of stress corrosion effect.

  9. Etude sur les tendons en materiaux composites et leur application aux ancrages postcontraints

    Science.gov (United States)

    Chennouf, Adil

    L'objectif general de la presente these est d'evaluer le comportement a l'arrachement et au fluage d'ancrages injectes constitues de tendons en materiaux composites afin d'etablir des recommandations plus appropriees et realistes pour le dimensionnement et la conception. Quatre types de tendons en materiaux composites, deux a base de fibres d'aramide et deux a base de fibres de carbone, ont ete utilises dans l'etude. Les travaux de recherche de cette these ont porte notamment sur: (I) Une caracterisation physique et mecanique des tendons en materiaux composites utilises dans l'etude. (II) Une etude en laboratoire sur les coulis de scellement. La premiere etape de cette etude a concerne le developpement d'un coulis de scellement performant adapte aux tendons en materiaux composites et a differentes situations d'injection. La seconde etape a traite des essais de caracterisations physique et mecanique du coulis de scellement developpe comparativement a trois coulis de scellement usuels d'un meme rapport E/L de 0,4. (III) Une etude sur des modeles reduits d'ancrages injectes. (IV) Une etude sur des modeles d'ancrages a grande echelle. La synthese de ces etudes a permis d'enoncer les principales conclusions suivantes: (1) Les valeurs moyennes des charges de rupture des tendons en materiaux composites ont ete de 1% a 29% superieures a celles specifiees par les manufacturiers. (2) L'etude sur les coulis de scellement a permis le developpement de coulis de ciment repondant aux criteres fixes, soient une grande stabilite, une bonne fluidite, une legere expansion et de bonnes caracteristiques mecaniques. (3) Les tendons en materiaux composites ont montre des contraintes d'adherence maximum superieures a celles des tendons en acier. (4) Le type de fibre, la configuration et le fini de surface des tendons en materiaux composites gouvernent leur resistance a l'adherence. (5) L'introduction de sable et d'autres ajouts comme les fines de silice et la poudre d'aluminium au coulis

  10. Magnetic resonance studies of solid polymers; Etude des polymeres solides par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [French] Cette etude est une recherche bibliographique sur l'application de la resonance magnetique nucleaire (RMN) aux polymeres solides. Dans la premiere partie theorique on discute les elements de la theorie de RMN, necessaires pour l'etude des proprietes des polymeres solides: la methode des moments, la relaxation nucleaire et la distribution des temps de correlation. La deuxieme partie presente les resultats des experiences. (auteur)

  11. 2,3,5-Trisubstituted pyridines as selective AKT inhibitors-Part I: Substitution at 2-position of the core pyridine for ROCK1 selectivity.

    Science.gov (United States)

    Lin, Hong; Yamashita, Dennis S; Zeng, Jin; Xie, Ren; Wang, Wenyong; Nidarmarthy, Sirishkumar; Luengo, Juan I; Rhodes, Nelson; Knick, Victoria B; Choudhry, Anthony E; Lai, Zhihong; Minthorn, Elisabeth A; Strum, Susan L; Wood, Edgar R; Elkins, Patricia A; Concha, Nestor O; Heerding, Dirk A

    2010-01-15

    2,3,5-Trisubstituted pyridines have been designed as potent AKT inhibitors that are selective against ROCK1 based on the comparison between AKT and ROCK1 structures. Substitution at the 2-position of the core pyridine is the key element to provide selectivity against ROCK1. An X-ray co-crystal structure of 9p in PKA supports the proposed rationale of ROCK1 selectivity.

  12. Orientations of axially coordinated imidazoles and pyridines in crystal structures of model systems of cytochromes.

    Science.gov (United States)

    Rakić, Aleksandra A; Medaković, Vesna B; Zarić, Snezana D

    2006-01-01

    Many properties of cytochromes and model systems depend on orientations of axial ligands. In this work, we elucidated the role of porphyrin substituents on orientation of axial ligands in model systems of cytochromes. The orientations of axially coordinated imidazoles and pyridines in crystal structures of model systems of cytochromes were analyzed and data were compared with previous quantum-chemical calculations. The results show that eight ethyl groups on porphyrin ring strongly favor parallel orientation, hence, in all these complexes axial ligands, pyridines or imidazoles, are mutually parallel. Four phenyl or mesityl groups at meso-carbons also favor parallel orientation but less strongly. Hence, in most of the bis-imidazole complexes the orientation is parallel, while in bis-pyridine complexes the orientation of pyridines depends on oxidation state of Fe. In bis-pyridine Fe(II) complexes orientation is parallel, in Fe(III) it is orthogonal. This analysis is in agreement with previous quantum-chemical calculations.

  13. Application of Ultraviolet and Ultrasound Irradiation for the Degradation of Pyridine in Wastewater: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Mohamed Elsayed

    2015-01-01

    Full Text Available The photochemical and sonochemical degradation of aqueous solutions of pyridine, a common refractory pollutant in wastewater effluents, have been investigated by means of ultraviolet (UV, ultrasound (US, UV/H2O2, and US/H2O2 irradiation processes. The pure photochemical process were demonstrated to be efficient for degradation of low initial concentrations of pyridine (10 ppm. Sonochemical degradation proceeded very slowly, leading to less than 53% of pyridine removal after 200 min. The degradation efficiency was increased with increasing H2O2 concentration; however, the marginal benefit became decreasing with further increasing of H2O2 due to the scavenging effect of excess H2O2. The kinetics of photochemical and sonochemical degradation of pyridine were found to follow a first-order rate law. A possible degradation pathway for pyridine was also proposed.

  14. Chemical and mineralogical size segregation in the impact disruption of anhydrous stone meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, G.J.; Durda, D.D. (SUNYP); (SW Research Institute)

    2005-02-02

    We performed impact disruption experiments on pieces from eight different anhydrous chondritic meteorites - four weathered ordinary chondrite finds from North Africa (NWA791, NWA620, NWA869 and MOR001), three almost unweathered ordinary chondrite falls (Mbale, Gao, and Saratov), and an almost unweathered carbonaceous chondrite fall (Allende). In each case the impactor was a small (1/8 or 1/4 in) aluminum sphere fired at the meteorite target at {approx} 5 km/s, comparable to the mean collision speed in the main-belt. Some of the {approx}5 to {approx} 150 {micro}m debris from each disruption was collected in aerogel capture cells, and the captured particles were analyzed by in situ synchrotron-based X-ray fluorescence. For each meteorite, many of the smallest particles (< 10 {micro}m up to 35 {micro}m in size, depending on the meteorite) exhibit very high Ni/Fe ratios compared to the Ni/Fe ratios measured in the larger particles (> 45 {micro}m), a composition consistent with the smallest debris being dominated by matrix material while the larger debris is dominated by fragments from olivine chondrules. These results may explain why the {approx} 10 {micro}m interplanetary dust particles (IDPs) collected from the Earth's stratosphere are C-rich and volatile-rich compared to the presumed solar nebula composition. The {approx} 10 {micro}m IDPs may simply sample the matrix of an inhomogeneous parent body, structurally and mineralogically similar to the chondritic meteorites, which are inhomogeneous assemblages of compact, strong, C- and volatile-poor chondrules that are distributed in a more porous, C- and volatile-rich matrix. In addition, these results may explain why the micrometeorites, which are {approx} 50 {micro}m to millimeters in size, recovered from the polar ices are Ni- and S-poor compared to chondritic meteorites, since these polar micrometeorites may preferentially sample fragments from the Ni- and S-poor olivine chondrules. These results indicate that

  15. Co-conformational Exchange Triggered by Molecular Recognition in a Di(acylamino)pyridine-Based Molecular Shuttle Containing Two Pyridine Rings at the Macrocycle.

    Science.gov (United States)

    Martinez-Cuezva, Alberto; Carro-Guillen, Fernando; Pastor, Aurelia; Marin-Luna, Marta; Orenes, Raul-Angel; Alajarin, Mateo; Berna, Jose

    2016-06-17

    We describe the incorporation of endo-pyridine units into the tetralactam ring of di(acylamino)pyridine-based rotaxanes. This macrocycle strongly associates with the linear interlocked component as confirmed by X-ray diffraction studies of rotaxane 2 b. Dynamic NMR studies of 2 b in solution revealed a rotational energy barrier that was higher than that of the related rotaxane 2 a, which lacks of pyridine rings in the macrocycle. The macrocycle distribution of the molecular shuttle 4 b, containing two endo-pyridine rings, shows that the major co-conformer is that with the cyclic component sitting over the di(acylamino)pyridine station. DFT calculations also support the marked preference of the ring for occupying the heterocyclic binding site. The association of N-hexylthymine with the di(acylamino)pyridine binding site of 4 b led to the formation of a rare 'S'-shaped co-conformer in which the tetralactam ring interacts simultaneously with both stations of the thread.

  16. Raman vapor spectrum and vibrational assignment for pyridine

    Science.gov (United States)

    Klots, T. D.

    1998-09-01

    Assignment modifications for the pyridine fundamentals are proposed, based on first time Raman vapor measurements, and a more complete set of infrared and Raman spectra for the gas and liquid. Raman polarization measurements are newly given for some 70 lines between 1600 and 3000 cm -1. The Kakiuti et al. (Kakiuti et al., J. Mol. Spectrosc. 61 (1976) 164) assignment for the nonplanar modes in CS 2 solution is shown to be the only previous correct assignment. Planar assignment modifications, though generally small, are warranted because of the benchmark nature of pyridine. A previous set of vibrational frequencies, derived from a scaled 4-21G force field calculation (Pongor et al., J. Am. Chem. Soc. 106 (1984) 2765; Pongor et al., J. Mol. Spectrosc. 114 (1985) 445), is in excellent agreement with the observed fundamentals, and in fact, tips the balance in favor of assigning ν22 to 1053 cm -1. Ideal-gas entropies derived from spectroscopic constants are also seen to be in excellent agreement with those from calorimetry (Chirico et al., J. Chem. Thermodyn. 28 (1996) 797; Chirico and Steele, J. Chem. Thermodyn. 28 (1996) 819).

  17. Determination of impurities in crude light pyridine bases

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, E.G.; Tsaur, A.G.; Lisina, L.A.; Dybkin, P.A.

    1981-01-01

    Hydrogen cyanide, hydrogen sulfide, ammonia and phenols are always products of coal pyrolysis. In addition the coke oven gas contains carbon disulfide. The simultaneous presence of ammonia and carbon disulfide leads inevitably to the formation of thiocyanates in the entire recovery system before the saturator, and particularly in the ammonia liquor. All these compounds may be expected to be present in the crude light pyridine bases (CLPB). This causes corrosion of the equipment and reduces the photostability of the final process products. The ability of the phenols to form high boiling point azeotropes with the bases reduces the ..beta..-picoline fraction yield. For these reasons the presence of the stated impurities in the CLPB is undesirable. In the present work an estimate has been made of the average annual concentration of phenols, cyanides, thiocyanates and chlorides in the crude light pyridine bases of all the plants supplying this material in the Eastern USSR. The table shows only the mean values of the concentrations for each component in the samples of the individual plants, and also those for water.

  18. Pyridine analogues of spirocyclic σ₁ receptor ligands.

    Science.gov (United States)

    Miyata, Kengo; Möller, Guido; Schepmann, Dirk; Wünsch, Bernhard

    2014-08-01

    Spirocyclic benzopyrans 2 interact with high affinity and selectivity with σ₁ receptors. Bioisosteric replacement of the benzene ring of the benzopyran substructure with the electron rich thiophene ring (3) led to increased σ₁ affinity. Herein the synthesis and pharmacological evaluation of electron deficient pyridine bioisosteres 4 are reported. Homologation of the aldehyde 6 to afford the pyridylacetaldehyde derivative 8 was performed by a Wittig reaction. Bromine lithium exchange of the bromopyridine 8, addition to 1-benzylpiperidin-4-one and cyclization led to the spirocyclic pyrranopyridine 10. Hydrogenolytic removal of the N-benzyl moiety of 10 provided the secondary amine 11, which allowed the introduction of various N-substituents (12a-d). Cyclization of the hydroxy acetal 9 with HCl led to various modifications of the substituent in 3'-position. Generally the σ₁ affinity of the pyridine derivatives is reduced compared with those of the benzene and thiophene derivatives 2 and 3. However, the relationships between the structure and the σ₁ affinity follow the same rules as for the benzene and thiophene derivatives. The most promising σ₁ ligand within this class of compounds is the pyranopyridine 15 with a double bond in the pyran ring revealing a Ki-value of 4.6 nM and a very high selectivity (>217-fold) over the σ₂ subtype.

  19. Synthesis and cytotoxicity of thieno[2,3-b]pyridine and furo[2,3-b]pyridine derivatives.

    Science.gov (United States)

    Hung, Joy M; Arabshahi, Homayon J; Leung, Euphemia; Reynisson, Jóhannes; Barker, David

    2014-10-30

    Forty seven thieno[2,3-b]pyridines-2-carboxamides, furo[2,3-b]pyridines-2-carboxamides and tetrahydrothieno[2,3-b]quinolones-2-carboxamides derivatives were synthesized and tested for their antiproliferative activity against the NCI-60 cell lines. The 5-keto-tetrahydrothieno[2,3-b]quinolones-2-carboxamides (series 17) were found to have the greatest activity, with the compound containing a 3-methoxyphenylcarboxamide (compound 17d) being the most active, with GI50 values in the low nanomolar range against a range of cell lines, in particular the melanoma cell line MDA-MD-435 (GI50 - 23 nM) and the breast cancer cell line MDA-MB-468 (GI50 - 46 nM). Molecular modelling of series 17 against phosphoinositide specific-phospholipase C reveals that the side chains of the amino acids His356, Glu341, Arg549 and Lys438 are involved in hydrogen bonding with the ligands as well as a lipophilic pocket is occupied by the phenyl carboxamide moiety.

  20. Hexaaquanickel(II tetraaquabis(μ-pyridine-2,6-dicarboxylatobis(pyridine-2,6-dicarboxylatotrinickelate(II octahydrate

    Directory of Open Access Journals (Sweden)

    Javad Safaei-Ghomi

    2010-08-01

    Full Text Available The title compound, [Ni(H2O6][Ni3(C7H3NO44(H2O4]·8H2O, was obtained by the reaction of nickel(II nitrate hexahydrate with pyridine-2,6-dicarboxylic acid (pydcH2 and 1,10-phenanothroline (phen in an aqueous solution. The latter ligand is not involved in formation of the title complex. There are three different NiII atoms in the asymmetric unit, two of which are located on inversion centers, and thus the [Ni(H2O6]2+ cation and the trinuclear {[Ni(pydc2]2-μ-Ni(H2O4}2− anion are centrosymmetric. All NiII atoms exhibit an octahedral coordination geometry. Various interactions, including numerous O—H...O and C—H...O hydrogen bonds and C—O...π stacking of the pyridine and carboxylate groups [3.570 (1, 3.758 (1 and 3.609 (1 Å], are observed in the crystal structure.

  1. In situ XRD Study of Ca2+ Saturated Montmorillonite (STX-1) Exposed to Anhydrous and Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Schaef, Herbert T.; Ilton, Eugene S.; Qafoku, Odeta; Martin, Paul F.; Felmy, Andrew R.; Rosso, Kevin M.

    2012-01-09

    Reactions involving scCO2 and a calcium saturated dioctahedral smectite (Ca-STX-1) were examined by in situ high-pressure x-ray diffraction over a range of temperatures (50° to 100°C) and pressures (90, 125, and 180 bar) relevant to long term geologic storage of CO2. Exposure of Ca-STX-1 containing one water of hydration (1W) to anhydrous scCO2 at 50°C and 90 bar produced an immediate increase of ~0.8 Å in the d001 basal reflection that was sustained for the length of the experiment (~44 hours). Higher ordered basal reflections displayed similar shifts. Following depressurization, positions of basal reflections and FWHM values (d001) returned to initial values, with no measurable modification to the clay structure or water content. Similar results were obtained for tests conducted at 50°C and higher pressures (125 and 180 bar). Exposure of Ca-STX-1 containing two waters of hydration (2W) to scCO2 resulted in a decrease in the d001 reflection from 14.48 Å to 12.52 Å, after pressurization, indicating a partial loss of interlayer water. In addition, the hydration state of the clay became more homogeneous during contact with anhydrous scCO2 and after depressurization. In the presence of scCO2 and water, the clay achieved a 3W hydration state, based on a d001 spacing of 18.8 Å. In contrast to scCO2, comparable testing with N2 gas indicated trivial changes in the d001 series regardless of hydration state (1W or 2W). In the presence of free water and N2, the basal spacing for the Ca-STX-1 expanded slightly, but remained in the 2W hydration state. These experiments indicate that scCO2 can intercalate hydrated clays, where the 1W hydrate state is stable when exposed to anhydrous scCO2 under conditions proposed for geologic storage of CO2. Consequently, clays can act as secondary CO2 traps where potential collapse or expansion of the interlayer spacing depends on the initial hydration state of the clay and scCO2.

  2. Structures of two co-crystals of pyridine betaine with L(+)-tartaric acid

    Science.gov (United States)

    Dega-Szafran, Z.; Dutkiewicz, G.; Kosturkiewicz, Z.

    2010-07-01

    Crystal structure of pyridine betaine with L(+)-tartaric acid, crystallized from methanol, is determined by X-ray diffraction methods. The crystal 1, at the 2:1 ratio of pyridine betaine and tartaric acid, is orthorhombic, space group P2 12 12 and contains disordered methanol guest molecules. Tartaric acid is bonded to two pyridine betaine molecules by the COOH···OOC hydrogen bonds of 2.443(2) Å. Complex 1 is situated at the special position, on twofold axis. After recrystallization of 1 from butanol crystal 2 is formed at the 3:1 ratio of pyridine betaine and semi-tartrate anion, without solvent molecules. Crystal 2 is monoclinic, space group P2 1 and shows an ionic character. Semi-tartrate anions form infinite chains and each anion is joined to one pyridine betaine molecule by the O-H···OOC hydrogen bonds, formed between two hydroxyl groups of semi-tartrate anion and the carboxylate oxygen atoms of pyridine betaine, of 2.772(2) and 2.738(2) Å. The counter-ion appears as a homoconjugated cation of two pyridine betaine molecules linked by the O·H·O hydrogen bond of 2.481(2) Å, using the proton transferred form tartaric acid. The FTIR and NMR spectra of 1 and 2 complexes are different. The 1H NMR spectrum in D 2O confirms the presence of methanol in 1.

  3. Semiconducting boron carbides with better charge extraction through the addition of pyridine moieties

    Science.gov (United States)

    Echeverria, Elena; Dong, Bin; Peterson, George; Silva, Joseph P.; Wilson, Ethiyal R.; Sky Driver, M.; Jun, Young-Si; Stucky, Galen D.; Knight, Sean; Hofmann, Tino; Han, Zhong-Kang; Shao, Nan; Gao, Yi; Mei, Wai-Ning; Nastasi, Michael; Dowben, Peter A.; Kelber, Jeffry A.

    2016-09-01

    The plasma-enhanced chemical vapor (PECVD) co-deposition of pyridine and 1,2 dicarbadodecaborane, 1,2-B10C2H12 (orthocarborane) results in semiconducting boron carbide composite films with a significantly better charge extraction than plasma-enhanced chemical vapor deposited semiconducting boron carbide synthesized from orthocarborane alone. The PECVD pyridine/orthocarborane based semiconducting boron carbide composites, with pyridine/orthocarborane ratios ~3:1 or 9:1 exhibit indirect band gaps of 1.8 eV or 1.6 eV, respectively. These energies are less than the corresponding exciton energies of 2.0 eV-2.1 eV. The capacitance/voltage and current/voltage measurements indicate the hole carrier lifetimes for PECVD pyridine/orthocarborane based semiconducting boron carbide composites (3:1) films of ~350 µs compared to values of  ⩽35 µs for the PECVD semiconducting boron carbide films fabricated without pyridine. The hole carrier lifetime values are significantly longer than the initial exciton decay times in the region of ~0.05 ns and 0.27 ns for PECVD semiconducting boron carbide films with and without pyridine, respectively, as suggested by the time-resolved photoluminescence. These data indicate enhanced electron-hole separation and charge carrier lifetimes in PECVD pyridine/orthocarborane based semiconducting boron carbide and are consistent with the results of zero bias neutron voltaic measurements indicating significantly enhanced charge collection efficiency.

  4. Etude theorique des fluctuations structurales dans les composes organiques a dimensionnalite reduite

    Science.gov (United States)

    Dumoulin, Benoit

    Les systemes a dimensionnalite reduite constituent maintenant une branche entiere de la physique de la matiere condensee. Cette derniere s'est developpee rapidement au cours des dernieres annees, avec la decouverte des materiaux organiques qui presentent, justement, des proprietes physiques fortement anisotropes. Cette these presente une etude en trois parties de plusieurs composes organiques qui, bien que tres differents du point de vue de leurs compositions chimiques et de leurs proprietes physiques a haute temperature, subissent tous une instabilite structurale a tres basse temperature. De plus, dans chacun des cas, l'instabilite structurale est precedee d'un important regime fluctuatif a partir duquel les proprietes physiques changent de maniere significative. Notre etude suit un ordre chronologique inverse puisque nous nous attardons en premier lieu au cas de composes recemment decouverts: les composes de la famille des (BCPTTF)2X (X = PF6 , AsF6). Ces derniers sont des isolants magnetiques a la temperature ambiante et subissent une instabilite structurale de type spin-Peierls a une temperature appelee TSP. En particulier, nous nous interessons a l'etude des proprietes physiques de ces systemes dans le regime fluctuatif, qui precede cette instabilite. Notre etude theorique nous permet de comprendre en detail comment ces systemes s'approchent de l'instabilite struturale. Dans la seconde partie de cette these, nous etudions le regime fluctuatif (pre-transitionnel) observe experimentalement dans le compose de (TMTTF)2PF6. Ce compose organique, dont la structure s'apparente aux sels de Bechgaard, subit une instabilite de type spin-Peierls a une temperature T SP = 19K. Bien que ce compose possede la particularite d'etre un bon conducteur a la temperature ambiante, il subit une transition de type Mott-Hubbard a une temperature Trho ≈ 220K et devient alors un isolant magnetique, analogue aux composes de la famille des (BCPTTF)2X. Le regime fluctuatif precedant l

  5. Thermal Decomposition of Anhydrous Alkali Metal Dodecaborates M2B12H12 (M = Li, Na, K

    Directory of Open Access Journals (Sweden)

    Liqing He

    2015-11-01

    Full Text Available Metal dodecaborates M2/nB12H12 are regarded as the dehydrogenation intermediates of metal borohydrides M(BH4n that are expected to be high density hydrogen storage materials. In this work, thermal decomposition processes of anhydrous alkali metal dodecaborates M2B12H12 (M = Li, Na, K synthesized by sintering of MBH4 (M = Li, Na, K and B10H14 have been systematically investigated in order to understand its role in the dehydrogenation of M(BH4n. Thermal decomposition of M2B12H12 indicates multistep pathways accompanying the formation of H-deficient monomers M2B12H12−x containing the icosahedral B12 skeletons and is followed by the formation of (M2B12Hzn polymers. The decomposition behaviors are different with the in situ formed M2B12H12 during the dehydrogenation of metal borohydrides.

  6. Kinetic analysis for non-isothermal decomposition of un-irradiated and gamma-irradiated anhydrous cadmium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Culas, S.; Samuel, J. [Mar Ivanios College, Kerala (India). Dept. of Chemistry

    2014-04-01

    The thermal decomposition of untreated and γ-irradiated samples of anhydrous cadmium nitrate was performed under non-isothermal conditions at different heating rates (5, 10, 15 and 20 C min{sup -1}). The results showed that the decomposition proceeds in one major step with the formation of cadmium oxide as solid residue. The data were analysed by using both isoconversional and non-isoconversional methods. The activation energy was calculated by various model-free isoconversional methods: Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Friedman (FR) methods. Irradiation enhances the decomposition and the effect increases with the irradiation dose. The activation energy decreases on irradiation. The appropriate conversion model for the thermal decomposition process selected by means of the master-plot method agrees with phase boundary reaction with spherical symmetry (R3 mechanism) for both untreated and irradiated salts at all heating rates. (orig.)

  7. Quantitative determination of amorphous nicardipine hydrochloride in long acting formula (NIC-LA) using light anhydrous silicic acid.

    Science.gov (United States)

    Kohinata, Takeru; Fujii, Mitsuo; Nakamura, Souichiro; Hamada, Noritaka; Yonemochi, Etsuo; Terada, Katsuhide

    2004-12-01

    We investigated a method to quantitatively determine amorphous nicardipine hydrochloride (NIC) in the NIC-long acting formula (LA) model formulas prepared using NIC, light anhydrous silicic acid (LASA) and carboxymethylethylcellulose (CMEC). Consequently, since the quantity of total NIC in the formula can be determined by means of HPLC and crystal NIC can be determined by the differential scanning calorimetry (DSC) method because the heat of fusion (85.08 J/g) of NIC is constant and unaffected by excipients, we developed the HPLC-DSC method by which the quantity of amorphous NIC is calculated as the difference between the quantity of total NIC determined by HPLC and the quantity of crystal NIC determined by DSC. This practical HPLC-DSC method was confirmed to have good accuracy and reproducibility.

  8. Crystalline anhydrous {alpha},{alpha}-trehalose (polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose: A calorimetric study

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Susana S. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: susanapinto@ist.utl.pt; Diogo, Herminio P. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: hdiogo@ist.utl.pt; Moura-Ramos, Joaquim J. [Centro de Quimica-Fisica Molecular, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: mouraramos@ist.utl.pt

    2006-09-15

    The mean values of the standard massic energy of combustion of crystalline anhydrous {alpha},{alpha}-trehalose (C{sub 12}H{sub 22}O{sub 11}, polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose (C{sub 12}H{sub 26}O{sub 13}) measured by static-bomb combustion calorimetry in oxygen, at the temperature T=298.15K, are {delta}{sub c}u{sup o}=-(16434.05+/-4.50)J.g{sup -1} and {delta}{sub c}u{sup o}=-(14816.05+/-3.52)J.g{sup -1}, respectively. The standard (p{sup o}=0.1MPa) molar enthalpy of formation of these compounds were derived from the corresponding standard molar enthalpies of combustion, respectively, {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 22}O{sub 11},cr)=-(2240.9+/-3.9)kJ.mol{sup -1}, and {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 26}O{sub 13},cr)=-(2832.6+/-3.6)kJ.mol{sup -1}. The values of the standard enthalpies of formation obtained in this work, together with data on enthalpies of solution at infinite dilution ({delta}{sub sol}H{sup {approx}}) for crystalline dihydrate and amorphous anhydrous trehalose, allow a better insight on the thermodynamic description of the trehalose system which can provide, together with the future research on the subject, a contribution for understanding the metabolism in several organisms, as well as the phase transition between the different polymorphs.

  9. Recent Advances in Anhydrous Solvents for CO2 Capture: Ionic Liquids, Switchable Solvents, and Nanoparticle Organic Hybrid Materials

    Directory of Open Access Journals (Sweden)

    YOUNGJUNE ePARK

    2015-10-01

    Full Text Available CO2 capture by amine scrubbing, which has a high CO2 capture capacity and a rapid reaction rate, is the most employed and investigated approach to date. There are a number of recent large-scale demonstrations including the Boundary Dam Carbon Capture Project by SaskPower in Canada that have reported successful implementations of aqueous amine solvent in CO2 capture from flue gases. The findings from these demonstrations will significantly advance the field of CO2 capture in the coming years. While the latest efforts in aqueous amine solvents are exciting and promising, there are still several drawbacks to amine-based CO2 capture solvents including high volatility and corrosiveness of the amine solutions, as well as the high parasitic energy penalty during the solvent regeneration step. Thus, in a parallel effort, alternative CO2 capture solvents, which are often anhydrous, have been developed as the third-generation CO2 capture solvents. These novel classes of liquid materials include: Ionic Liquids (ILs, CO2-triggered switchable solvents (i.e., CO2 Binding Organic Liquids (CO2BOLs, Reversible Ionic Liquids (RevILs, and Nanoparticle Organic Hybrid Materials (NOHMs. This paper provides a review of these various anhydrous solvents and their potential for CO2 capture. Particular attention is given to the mechanisms of CO2 absorption in these solvents, their regeneration and their processability – especially taking into account their viscosity. While not intended to provide a complete coverage of the existing literature, this review aims at pointing the major findings reported for these new classes of CO2 capture media.

  10. 3-{[Bis(pyridin-2-ylmethylamino]methyl}-2-hydroxy-5-methylbenzaldehyde

    Directory of Open Access Journals (Sweden)

    Ruo-Xu Wang

    2012-06-01

    Full Text Available In the title compound, C21H21N3O2, the pyridine rings and the benzene ring lie in a propeller arrangement around the central tertiary amine N atom. The dihedral angles formed by the benzene ring with the pyridine rings are 61.0 (3 and 49.6 (3°, while the dihedral angle between the pyridine rings is 69.7 (3°. The molecular conformation is stabilized by intramolecular bifurcated O—H...N hydrogen bonds. In the crystal, inversion dimers are formed via pairs of C—H...N hydrogen bonds.

  11. Photo-physical studies of pyridine capped ZnO nanostructures

    Science.gov (United States)

    Bhatti, H. S.; Singh, Karamjit; Kavita; Kumar, Sunil; Choubey, R. K.

    2014-07-01

    Pyridine capped ZnO nanocrystals with different sizes were synthesized at room temperature by wet chemical synthesis. Pyridine provides the control over the morphology of final product. X-ray study confirms the crystalline hexagonal structure of the capped and uncapped ZnO nanocrystals. The particle size was found to decrease with increase in capping concentration. Electron microscopy investigation reveals the uniform morphology of the product. Optical absorption studies indicate the blue shift effect for pyridine capped ZnO as compare to uncapped ZnO.

  12. Synthesis and Characterization of Novel Polyimides Based on Pyridine-containing Diamine

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new aromatic diamine monomer containing pyridine unit, 2,6-bis (4-aminophenoxy4′-benzoyl)pyridine(BABP), was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared via the polycondensation of BABP with various aromatic dianhydrides through poly(amic acid) precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties,e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and ftlm-forming capability, as well as high inherent viscosity, indicating high molecular weight.

  13. Influence of deuteration and fluorination on the supramolecular architecture of pyridine N-oxide crystals.

    Science.gov (United States)

    Shishkin, Oleg V; Shishkina, Svitlana V; Maleev, Andrey V; Zubatyuk, Roman I; Vasylyeva, Vera; Merz, Klaus

    2013-03-18

    To understand how deuterium and fluorine substituents influence the supramolecular architecture of pyridine N-oxide crystals, the crystal structure of 3-fluoropyridine N-oxide (PNO-3F) was determined and the crystal packing motives of non-deuterated pyridine-N-oxide (PNO), partial-deuterated pyridine-N-oxide (PNO-D) and PNO-3F were analyzed based on ab initio quantum-chemical calculations of the intermolecular interaction energy, using the MP2/6-311G(d,p) method. The appearance of the weak-directing substituents deuterium and fluorine leads to significant changes in the crystal organization of the isotropic packing of PNO molecules.

  14. Pretreatment of corn stover by low moisture anhydrous ammonia (LMMA) in a pilot-scale reactor and bioconversion to fuel ethanol and industrial chemicals

    Science.gov (United States)

    Corn stover (CS) adjusted to 50%, 66% and 70% moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70% moisture CS was treated at 90 degree C and 100 degree C whereas the others were treated at 90 degree C only. The...

  15. Control of powdery mildew on glasshouse-grown roses and tomatoes in the Netherlands using anhydrous milk fat and soybean oil emulsions

    NARCIS (Netherlands)

    Wurms, K.V.; Hofland-Zijlstra, Jantineke

    2015-01-01

    Powdery mildew (PM) is a very serious disease affecting glasshouse-grown roses and tomatoes in the Netherlands. Control is limited because of resistance to existing fungicides. Anhydrous milk fat (AMF) and soybean oil (SBO) emulsions were evaluated for control of PM in roses and tomatoes. Both AM

  16. Trace element partitioning between ilmenite, armalcolite and anhydrous silicate melt: Implications for the formation of lunar high-Ti mare basalts

    NARCIS (Netherlands)

    Kan Parker, M. van; Mason, P.R.D.; Westrenen, W. van

    2011-01-01

    We performed a series of experiments at high pressures and temperatures to determine the partitioning of a wide range of trace elements between ilmenite (Ilm), armalcolite (Arm) and anhydrous lunar silicate melt, to constrain geochemical models of the formation of titanium-rich melts in the Moon. Ex

  17. Synthesis and characterization of oxovanadium (IV) dithiocarbamates with pyridine

    Energy Technology Data Exchange (ETDEWEB)

    Doadrio, Antonio L.; Sotelo, Jose; Fernandez-Ruano, Ana [Universidad Complutense, Madrid (Spain). Facultad de Farmacia. Dept. de Quimica Inorganica y Bioinorganica]. E-mail: antoniov@farm.ucm.es

    2002-07-01

    We report the synthesis and study of a new series of oxovanadium (IV) dithiocarbamate adducts and derivatives with pyridine and cyclohexyl, di-iso-butyl, di-n-propyl, aniline, morpholine, piperidine and di-iso-propyl amines. The complexes have been characterized by analytical, magneto chemical, IR, visible-UV spectral and thermal studies, and are assigned the formulas [VO(L){sub 2}].py, where L=cyclohexyl, di-iso-butyl, di-n-propyl, aniline dithiocarbamate and [VO(OH)(L)(py){sub 2}] OH.H{sub 2}O (L=morpholine, piperidine and di-iso-propyl dithiocarbamate). The effect of the adduct formation on the p{sub V=0} bound is discussed in terms of the IR (V=O, V-S and V-N stretching frequencies) and electronic spectra (d-d transitions). (author)

  18. Organic Electrofluorescent Materials Using Pyridine-Containing Macrocyclic Compounds

    Institute of Scientific and Technical Information of China (English)

    Tingxi LI; Long FU; Wenwen YU; Renhe HUANG

    2008-01-01

    Novel pyridine-containing macrocyclic compounds, such as 6,12,19,25-tetramethyl-7,11,20,24-dinitrilo-dibenzo[b,m]l,4,12,15-tetra-azacyclodoc osine (TMCD), were synthesized and used as electron transport layer in organic electroluminescent devices. Devices with a structure of glass/indium-tin oxide/arylamine derivative/tris(quinolinolato)aluminum(Ⅲ) (AIq)/TMCD/LiF/AI exhibited green emission from the Alq layer with external quantum efficiency of 0.84% and luminous efficiency of 1.3 lm/W. The derivatives of TMCD were synthesized and characterized as well. These compounds were also found to be useful as the electron-transporting materials in organic electroluminescent devices.

  19. Synthesis and characterization of oxovanadium (IV dithiocarbamates with pyridine

    Directory of Open Access Journals (Sweden)

    Antonio L. Doadrio

    2002-07-01

    Full Text Available We report the synthesis and study of a new series of oxovanadium (IV dithiocarbamate adducts and derivatives with pyridine and cyclohexyl, di-iso-butyl, di-n-propyl, anilin, morpholin, piperidin and di-iso-propyl amines. The complexes have been characterized by analytical, magnetochemical, IR, visible-UV spectral and thermal studies, and are assigned the formulas [VO(L2].py, where L=cyclohexyl, di-iso-butyl, di-n-propyl, anilin dithiocarbamate and [VO(OH(L(py2]OH.H2O (L=morpholin, piperidin and di-iso-propyl dithiocarbamate. The effect of the adduct formation on the pV=0 bound is discussed in terms of the IR (V=O, V-S and V-N stretching frequencies and electronic spectra (d-d transitions.

  20. Identification of pyridine analogues as new predator-derived kairomones

    Directory of Open Access Journals (Sweden)

    Julien eBrechbühl

    2015-07-01

    Full Text Available In the wild, animals have developed survival strategies relying on their senses. The individual ability to identify threatening situations is crucial and leads to increase in the overall fitness of the species. Rodents, for example have developed in their nasal cavities specialized olfactory neurons implicated in the detection of volatile cues encoding for impending danger such as predator scents or alarm pheromones. In particular, the neurons of the Grueneberg ganglion (GG, an olfactory subsystem, are implicated in the detection of danger cues sharing a similar chemical signature, a heterocyclic sulfur- or nitrogen-containing motif. Here we used a from the wild to the lab approach to identify new molecules that are involuntarily emitted by predators and that initiate fear-related responses in the recipient animal, the putative prey. We collected urines from carnivores as sources of predator scents and first verified their impact on the blood pressure of the mice. With this approach, the urine of the mountain lion emerged as the most potent source of chemical stress. We then identified in this biological fluid, new volatile cues with characteristic GG-related fingerprints, in particular the methylated pyridine structures, 2,4-lutidine and its analogues. We finally verified their encoded danger quality and demonstrated their ability to mimic the effects of the predator urine on GG neurons, on mice blood pressure and in behavioral experiments. In summary, we were able to identify here, with the use of an integrative approach, new relevant molecules, the pyridine analogues, implicated in interspecies danger communication.

  1. (2Z-3-Hydroxy-1-(pyridin-2-yl-3-(pyridin-3-ylprop-2-en-1-one: crystal structure and Hirshfeld surface analysis

    Directory of Open Access Journals (Sweden)

    Sze-Ling Lee

    2016-06-01

    Full Text Available The title compound, C13H10N2O2 [also called 1-(pyridin-2-yl-3-(pyridin-3-ylpropane-1,3-dione], features an almost planar (r.m.s. deviation = 0.0095 Å central C3O2 core consolidated by an intramolecular hydroxy-O—H...O(carbonyl hydrogen bond. Twists are evident in the molecule, as seen in the dihedral angles between the central core and the 2- and pyridin-3-yl rings of 8.91 (7 and 15.88 (6°, respectively. The conformation about the C=C bond [1.3931 (17 Å] is Z, and the N atoms lie to the same side of the molecule. In the molecular packing, supramolecular chains along the a axis are mediated by π(pyridin-2-yl–π(pyridin-3-yl interactions [inter-centroid distance = 3.7662 (9 Å]. The observation that chains pack with no directional interactions between them is consistent with the calculated electrostatic potential, which indicates that repulsive interactions dominate.

  2. Anhydrate to hydrate solid-state transformations of carbamazepine and nitrofurantoin in biorelevant media studied in situ using time-resolved synchrotron X-ray diffraction.

    Science.gov (United States)

    Boetker, Johan P; Rantanen, Jukka; Arnfast, Lærke; Doreth, Maria; Raijada, Dhara; Loebmann, Korbinian; Madsen, Cecilie; Khan, Jamal; Rades, Thomas; Müllertz, Anette; Hawley, Adrian; Thomas, Diana; Boyd, Ben J

    2016-03-01

    Transformation of the solid-state form of a drug compound in the lumen of the gastrointestinal tract may alter the drug bioavailability and in extreme cases result in patient fatalities. The solution-mediated anhydrate-to-hydrate phase transformation was examined using an in vitro model with different biorelevant media, simulated fasted and fed state intestinal fluids containing bile salt and dioleoylphosphatidylcholine (DOPC) micelles, DOPC/sodium dodecyl sulfate (SDS) mixture, bile salt solution and water. Two anhydrate compounds (carbamazepine, CBZ and nitrofurantoin, NF) with different overall transformation time into hydrate form were used as model compounds. The transformations were monitored using direct structural information from time-resolved synchrotron X-ray diffraction. The kinetics of these transformations were estimated using multivariate data analysis (principal component analysis, PCA) and compared to those for nitrofurantoin (NF). The study showed that the solution-mediated phase transformation of CBZ anhydrate was remarkably faster in the DOPC/SDS medium compared to transformation in all the other aqueous dispersion media. The conversion time for CBZ anhydrate in water was shorter than for DOPC/SDS but still faster than the conversion seen in fed and fasted state micellar media. The conversion of CBZ anhydrate to hydrate was the slowest in the solution containing bile salt alone. In contrast, the solution-mediated phase transformations of NF did only show limited kinetic dependence on the dispersion media used, indicating the complexity of the nucleation process. Furthermore, when the CBZ and NF material was compacted into tablets the transformation times were remarkably slower. Results suggest that variations in the composition of the contents of the stomach/gut may affect the recrystallization kinetics, especially when investigating compounds with relatively fast overall transformation time, such as CBZ.

  3. Poly[[tetraaquatetrakis[μ3-5-(pyridine-4-carboxamidoisophthalato]cobalt(IIdiholmium(III] tetrahydrate

    Directory of Open Access Journals (Sweden)

    Yi-Fang Deng

    2011-11-01

    Full Text Available In the centrosymmetric polymeric title compound, {[CoHo2(C14H8N2O54(H2O4]·4H2O}n, the HoIII ion is coordinated by one water molecule and four 5-(pyridine-4-carboxamidoisophthalate (L ligands in a distorted square-antiprismatic arrangement. The CoII ion, located on an inversion center, is coordinated by two pyridine N atoms, two carboxylate O atoms and two water molecules in a distorted octahedral geometry. One L ligand bridges two Ho ions and one Co ion through two carboxylate groups and one pyridine N atom. The other L ligand bridges two Ho ions and one Co ion through two carboxylate groups, while the uncoordinated pyridine N atom accepts a hydrogen bond from an adjacent coordinated water molecule. Extensive O—H...O, N—H...O and O—H...N hydrogen bonding is present in the crystal.

  4. Determination of Pyridine in Modified JP-4 VIA High Performance Liquid Chromatography (HPLC).

    Science.gov (United States)

    1981-04-01

    data collection and calculations automatically, with the results printed on a teletype. Least square curve fitting accentuated the reliability for determining pyridine in the 0.5 to 5.0 weight percent concentration range. (Author)

  5. Crystal structure of N,N′-bis[(pyridin-4-ylmethyl]naphthalene diimide

    Directory of Open Access Journals (Sweden)

    Mariana Nicolas-Gomez

    2014-09-01

    Full Text Available In the centrosymmetric title compound, C26H16N4O4 {systematic name: 6,13-bis[(pyridin-4-ylmethyl]-6,13-diazatetracyclo[6.6.2.04,16011,15]hexadeca-1,3,8,10,15-pantaene-5,7,12,14-tetrone}, the central ring system is essentially planar [maximum deviation = 0.0234 (8 Å] and approximately perpendicular to the terminal pyridine ring [dihedral angle = 84.38 (3°]. The molecules displays a trans conformation with the (pyridin-4-ylmethyl groups on both sides of the central naphthalene diimide plane. In the crystal, molecules are linked by π–π stacking between parallel pyridine rings [centroid–centroid distances = 3.7014 (8 and 3.8553 (8 Å] and weak C—H...O hydrogen bonds, forming a three-dimensional supramolecular architecture.

  6. Antimicrobial evaluation of new synthesized pyridine nucleosides under solvent-free conditions.

    Science.gov (United States)

    Rateb, Nora M; El-Deab, Hany A; Abdou, Ibrahim M

    2013-01-01

    Two series of novel 3-cyano-2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxo) pyridines and 3-cyano-2-(2,3,5-tri-O-acetyl-β-D-ribofuranosyloxy)-4-trifluromethyl-6-phenyl pyridine were synthesized using efficient microwave methods. The targeted compounds were obtained in high yields by reacting 2-(1H)-pyridone or its salt with activated sugars using SiO₂ under solvent-free conditions. Ammonolysis of the resulted acetylated nucleosides produced 3-cyano-2-(β-D-glucopyranosyloxo)-pyridines and 3-cyano-2-(β-D-ribofuranosyloxy)-4-trifluoromethyl-6-phenyl pyridine. These new products were fully characterized using 1D and 2D NMR. These compounds were screened for their antibacterial activities against G(+) and G(-) bacteria and some found to exhibit better antibacterial activities than the control drug.

  7. Elimination and migration of hydrogen in the vacuum-ultraviolet photodissociation of pyridine molecules

    Science.gov (United States)

    Wasowicz, Tomasz J.; Dąbkowska, Iwona; Kivimäki, Antti; Coreno, Marcello; Zubek, Mariusz

    2017-01-01

    Elimination of the excited hydrogen atoms H(n), n = 4-7, and hydrogen migration in formation of the excited NH(A 3Π) free radicals in the photodissociation of pyridine, C5H5N, molecules have been studied over the 17.5-70 eV photon energy range. In the measurements the photon-induced fluorescence spectroscopy technique has been applied. Both fragments are produced through excitation of pyridine molecules into higher-lying superexcited Rydberg or doubly excited states. The mechanisms for fragmentation of pyridine into H(n) and NH(A 3Π) are discussed. Ab initio quantum chemical calculations have been performed to elucidate the hydrogen migration mechanism in the NH formation, which is not a self-contained unit in the structure of pyridine.

  8. Atmospheric degradation of pyridine: UV absorption spectrum and reaction with OH radicals and O3

    Science.gov (United States)

    Errami, M.; El Dib, G.; Cazaunau, M.; Roth, E.; Salghi, R.; Mellouki, A.; Chakir, A.

    2016-10-01

    The UV absorption spectrum of pyridine and its gas phase reactions with OH radicals and O3 were investigated. UV absorption cross-sections were determined by using a D2-lamp system in the range 200-350 nm. The kinetic studies were carried out at room temperature and atmospheric pressure of purified air. The rate coefficient for the reaction of pyridine with OH was determined relative to that with acetone while that with O3 was measured under pseudo first order conditions. The rate coefficients obtained are (in cm3 molecule-1 s-1): k(OH + pyridine) = (5.40 ± 0.80) × 10-13 and k(O3 + pyridine) = (3.28 ± 1.70) × 10-20.

  9. The structure of 3-(diethylborylethynyl)pyridine: a nonplanarly arranged cyclic trimer.

    Science.gov (United States)

    Wakabayashi, Shigeharu; Kuse, Mitsumi; Kida, Aimi; Komeda, Seiji; Tatsumi, Kazuyuki; Sugihara, Yoshikazu

    2014-08-07

    3-(Diethylborylethynyl)pyridines 2 assemble into a cyclic trimer stabilized via intermolecular boron–nitrogen coordination bonds both in solution and in the crystalline state. The outstanding structural features of the methoxy derivative 2b in the crystalline state are that (1) two pyridine rings (P1 and P2) of the cyclic trimer of 2b are almost coplanar, and the third pyridine ring (P3) is largely bent away from P1 and P2, and (2) P3 of the cyclic trimer stacks in a face-to-face fashion with one of the pyridine rings (P3’) of an adjacent cyclic trimer. The crystallographic study revealed that the conformation of the cyclic trimer is flexible enough to be affected by the crystal packing.

  10. Pyridine derivatives as insecticides. Part 1: synthesis and toxicity of some pyridine derivatives against cowpea aphid, Aphis craccivora Koch (Homoptera: Aphididae).

    Science.gov (United States)

    Bakhite, Etify A; Abd-Ella, Aly A; El-Sayed, Mohamed E A; Abdel-Raheem, Shaban A A

    2014-10-15

    Five pyridine derivatives, namely, N-morpholinium 7,7-dimethyl-3-cyano-4-(4'-nitrophenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-2-thiolate (1), sodium 5-acetyl-3-amino-4-(4'-methoxyphenyl)-6-methylthieno[2,3-b] pyridine-2-carboxylate (2), piperidinium 3,5-dicyano-2-oxo-4-spirocyclopentane-1,2,3,4-tetrahydropyridine-6-thiolate (3), piperidinium 5-acetyl-3-cyano-4-(4'-methoxyphenyl)-6-methylpyridine-2-thiolate (4), and piperidinium 5-acetyl-4-(4'-chlorophenyl)-3-cyano-6-methyl-pyridine-2-thiolate (5) were prepared in pure state and subjected to the title study. The bioassay results indicated that the insecticidal activity of compound 1 is about 4-fold that of acetamiprid insecticide. The rest of the tested compounds possess moderate to strong aphidicidal activities.

  11. Dibromidobis(pyridine-3-carbonitrile-κN1mercury(II

    Directory of Open Access Journals (Sweden)

    Reza Ghiasi

    2011-05-01

    Full Text Available In the crystal structure of the title compound, [HgBr2(C6H4N22], the Hg atom is four coordinated by two pyridine N atoms and two Br− anions in a considerably distorted tetrahedral environment. π–π interactions between adjacent pyridine rings [centroid–centroid distance of 3.648 (3 Å] stabilize the crystal structure.

  12. Synthesis and evaluation of antitumor activity ofsome thiazolo[4,5-b]pyridines

    Directory of Open Access Journals (Sweden)

    Ogurtsov V. V.

    2012-09-01

    Full Text Available Aim. To synthesize a series of novel 3H-thiazolo[4,5-b]pyridine-2-ones by structural modification of the core heterocycle in its N3- and N6-positions and to evaluate their anticancer activity in vitro on several tumor cell lines. Methods. Organic synthesis, 1H-NMR spectroscopy, trypan blue cell viability assay. Results. A new convenient synthetic approach was developed and optimized conditions were studied for the reaction of preparation of 3H- thiazolo[4,5-b]pyridin-2-one derivatives. 5,7-Dimethyl-3H-thiazolo[4,5-b]pyridin-2-one and 6-phenylazo-5,7- dimethyl-3H-thiazolo[4,5-b]pyridin-2-one were obtained by [3 + 3]cyclocondensation of 4-iminothiazolidone- 2 with acetylacetone and phenylazoacetylacetone in methanol medium in the presence of sodium methylate. They were used as starting compounds for further structural modification of the core thiazolo[4,5-b]pyridine heterocycle in its 3- and 6-positions. On the basis of in vitro cytotoxicity studies of synthesized compounds several structure-functional relationships underlying anticancer potential of 5,7-dimethyl-3H-thiazolo[4,5-b]pyridin- 2-one derivatives were identified. Conclusions. 3H-thiazolo[4,5-b]pyridin-2-one can be considered as a promising molecular scaffold for rational design of potential anticancer drug candidates. Introduction of phenylazo substitute at C6-position of 3H-thiazolo[4,5-b]pyridin-2-one proved to be the most efficient, as it led to 3-fold increase of its anticancer potential.

  13. Synthesis of 2, 6-(substituded) pyridine Derivatives Using Amide and Imine Groups

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new ‘two-armed' acyclic diamide Ⅰa 2, 6-bis(1-ethanecarbozamido-2-amino)pyridine,and a new series of aromatic aldehyde schiff bases containing pyridine ring and amide bridge, Ⅱa-f,were prepared. The compounds were characterized by elemental analysis, IR, 1HNMR and MS.The bioactivity half inhibitory concentration C1/2 is given.

  14. N,N′-(Ethane-1,2-diyldi-o-phenylenebis(pyridine-2-carboxamide

    Directory of Open Access Journals (Sweden)

    Shuranjan Sarkar

    2011-11-01

    Full Text Available The title molecule, C26H22N4O2, is centrosymmetric and adopts an anti conformation. Two intramolecular hydrogen bonds, viz. amide–pyridine N—H...N and phenyl–amide C—H...O, stabilize the trans conformation of the (pyridine-2-carboxamidophenyl group about the amide plane. In the crystal, the presence of weak intermolecular C—H...O hydrogen bonds results in the formation of a three-dimensional network.

  15. Dihydro-β-agarofuran sesquiterpene pyridine alkaloids from the seeds of Euonymus hamiltonianus

    Directory of Open Access Journals (Sweden)

    Mudasir A. Tantry

    2016-09-01

    Full Text Available Plants of the Celastraceae family produce various dihydro-β-agarofuran sesquiterpene pyridine alkaloids. Two dihydro-β-agarofuran sesquitepene pyridine alkaloids (1,2 apart from four known compounds euojaponin C (3, wilforine (4, austronine (5 and O9-benzoyl-O9-deacetylevonine (6, were isolated from the ripe seeds of Euonymus hamiltonianus. Their chemical structures were elucidated mainly by analysis of NMR and MS spectral data. All compounds were evaluated for insecticidal activity.

  16. Investigating the Effect of Pyridine Vapor Treatment on Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Alison [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    Perovskite photovoltaics have recently come to prominence as a viable alternative to crystalline silicon based solar cells. In an effort to create consistent and high-quality films, we studied the effect of various annealing conditions as well as the effect of pyridine vapor treatment on mixed halide methylammonium lead perovskite films. Of six conditions tested, we found that annealing at 100°C for 90 minutes followed by 120°C for 15 minutes resulted in the purest perovskite. Perovskite films made using that condition were treated with pyridine for various amounts of time, and the effects on perovskite microstructure were studied using x-ray diffraction, UV-Vis spectroscopy, and time-resolved photoluminescence lifetime analysis (TRPL). A previous study found that pyridine vapor caused perovskite films to have higher photoluminescence intensity and become more homogenous. In this study we found that the effects of pyridine are more complex: while films appeared to become more homogenous, a decrease in bulk photoluminescence lifetime was observed. In addition, the perovskite bandgap appeared to decrease with increased pyridine treatment time. Finally, X-ray diffraction showed that pyridine vapor treatment increased the perovskite (110) peak intensity but also often gave rise to new unidentified peaks, suggesting the formation of a foreign species. It was observed that the intensity of this unknown species had an inverse correlation with the increase in perovskite peak intensity, and also seemed to be correlated with the decrease in TRPL lifetime.

  17. On the formation of niacin (vitamin B3) and pyridine carboxylic acids in interstellar model ices

    Science.gov (United States)

    McMurtry, Brandon M.; Turner, Andrew M.; Saito, Sean E. J.; Kaiser, Ralf I.

    2016-06-01

    The formation of pyridine carboxylic acids in interstellar ice grains was simulated by electron exposures of binary pyridine (C5H5N)-carbon dioxide (CO2) ice mixtures at 10 K under contamination-free ultrahigh vacuum conditions. Chemical processing of the pristine ice and subsequent warm-up phase was monitored on line and in situ via Fourier transform infrared spectroscopy to probe for the formation of new radiation induced species. In the infrared spectra of the irradiated ice, bands assigned to nicotinic acid (niacin; vitamin B3; m-C5H4NCOOH) along with 2,3-, 2,5-, 3,4-, and 3,5-pyridine dicarboxylic acid (C5H3N(COOH)2) were unambiguously identified along with the hydroxycarbonyl (HOCO) radical. Our study suggests that the reactive pathway responsible for pyridine carboxylic acids formation involves a HOCO intermediate, which forms through the reaction of suprathermal hydrogen ejected from pyridine with carbon dioxide. The newly formed pyridinyl radical may then undergo radical-radical recombination with a hydroxycarbonyl radical to form a pyridine carboxylic acid.

  18. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    Science.gov (United States)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  19. Investigating the Effect of Pyridine Vapor Treatment on Perovskite Solar Cells - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Alison J. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    Perovskite photovoltaics have recently come to prominence as a viable alternative to crystalline silicon based solar cells. In an effort to create consistent and high-quality films, we studied the effect of various annealing conditions as well as the effect of pyridine vapor treatment on mixed halide methylammonium lead perovskite films. Of six conditions tested, we found that annealing at 100 degree Celsius for 90 minutes followed by 120 degree Celsius for 15 minutes resulted in the purest perovskite. Perovskite films made using that condition were treated with pyridine for various amounts of time, and the effects on perovskite microstructure were studied using x-ray diffraction, UV-Vis spectroscopy, and time-resolved photoluminescence lifetime analysis (TRPL). A previous study found that pyridine vapor caused perovskite films to have higher photoluminescence intensity and become more homogenous. In this study we found that the effects of pyridine are more complex: while films appeared to become more homogenous, a decrease in bulkphotoluminescence lifetime was observed. In addition, the perovskite bandgap appeared to decrease with increased pyridine treatment time. Finally, X-ray diffraction showed that pyridine vapor treatment increased the perovskite (110) peak intensity but also often gave rise to new unidentified peaks, suggesting the formation of a foreign species. It was observed that the intensity of this unknown species had an inverse correlation with the increase in perovskite peak intensity, and also seemed to be correlated with the decrease in TRPL lifetime.

  20. Regulation of Ca2+ release from mitochondria by the oxidation-reduction state of pyridine nucleotides.

    Science.gov (United States)

    Lehninger, A L; Vercesi, A; Bababunmi, E A

    1978-04-01

    Mitochondria from normal rat liver and heart, and also Ehrlich tumor cells, respiring on succinate as energy source in the presence of rotenone (to prevent net electron flow to oxygen from the endogenous pyridine nucleotides), rapidly take up Ca(2+) and retain it so long as the pyridine nucleotides are kept in the reduced state. When acetoacetate is added to bring the pyridine nucleotides into a more oxidized state, Ca(2+) is released to the medium. A subsequent addition of a reductant of the pyridine nucleotides such as beta-hydroxybutyrate, glutamate, or isocitrate causes reuptake of the released Ca(2+). Successive cycles of Ca(2+) release and uptake can be induced by shifting the redox state of the pyridine nucleotides to more oxidized and more reduced states, respectively. Similar observations were made when succinate oxidation was replaced as energy source by ascorbate oxidation or by the hydrolysis of ATP. These and other observations form the basis of a hypothesis for feedback regulation of Ca(2+)-dependent substrate- or energy-mobilizing enzymatic reactions by the uptake or release of mitochondrial Ca(2+), mediated by the cytosolic phosphate potential and the ATP-dependent reduction of mitochondrial pyridine nucleotides by reversal of electron transport.

  1. Electrochemical degradation of pyridine by Ti/SnO2-Sb tubular porous electrode.

    Science.gov (United States)

    Li, Duo; Tang, Jingyan; Zhou, Xiezhen; Li, Jiansheng; Sun, Xiuyun; Shen, Jinyou; Wang, Lianjun; Han, Weiqing

    2016-04-01

    Diffusion in electrochemistry is a critical issue for water purification. Electrocatalytic reactor system in improving water quality is a useful way to induce convection to enhance diffusion. This study focuses on the preparation and the characterization of Ti/SnO2-Sb tubular porous electrode for degrading pyridine wastewater. The electrode as an anode in reactor system is prepared by coating SnO2-Sb as an electro-catalyst via Pechini method on the tubular porous Ti. Scanning Electron Microscopy, Energy Dispersive Spectrum, X-ray Diffraction and Pore Distribution are employed to evaluate the structure and morphology of the electrodes coatings, and Linear Sweep Voltammetry and Cyclic Voltammetry are used to illustrate the electrochemical properties of the electrodes coatings. Furthermore, the electrochemical oxidation performance of Ti/SnO2-Sb tubular porous electrode is characterized by degrading pyridine wastewater. The effects of flow and static pattern, initial pyridine concentration, supporting electrolyte concentration, current density and pH on the performance of the reactor were investigated in the electrocatalytic reactor system. The results indicated that the removal ratio of pyridine reaches maximum which is 98% under the optimal operation conditions, that are 100 mg L(-1) initial pyridine concentration, 10 g L(-1) supporting electrolyte concentration, 30 mA cm(-2) current density and pH 3. Transition state calculation based on the density function theory was combined with High Performance Liquid Chromatography, Gas Chromatography and Ionic Chromatography results to describe the pathway of pyridine degradation.

  2. Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

    Institute of Scientific and Technical Information of China (English)

    LI Yongmei; LI Wenshu; GU Guowei

    2007-01-01

    Batch experiments were carried out to investigate the promotive effect ofpyridine on indole degradation under denitrifying conditions.The seed sludge was obtained from a local coal-coking wastewater treatment facility and was acclimated in the laboratory.Indole and pyridine were supplemented to the synthetic wastewater at different ratios.The optimum ratio of chemical oxygen demand (COD) to nitrate (C/N) was 8.4-8.9 for both denitrification and indole and pyridine degradation.At a temperature of 28℃ and pH of 7.0-7.5,the nitrate reductase activity (NRA) was in the best state.The addition of pyridine could promote NRA and the degradation of indole.When the initial concentration of indole was 150 mg/L,the concentration ratio of indole to pyridine was in the range of 1-10.Under optimum C/N conditions,the degradation of indole could be described with pseudo-zero-order kinetics.There was no accumulation of nitrite during the reaction.When the concentration ratio of pyridine to indole was less than 0.25 with an increase in the pyridine proportion,there were more significant augment rates for NRA and the degradation of indole than the situation when the concentration ratio was more than 0.25.

  3. Novel S1P1 receptor agonists - Part 5: From amino-to alkoxy-pyridines.

    Science.gov (United States)

    Bolli, Martin H; Lescop, Cyrille; Birker, Magdalena; de Kanter, Ruben; Hess, Patrick; Kohl, Christopher; Nayler, Oliver; Rey, Markus; Sieber, Patrick; Velker, Jörg; Weller, Thomas; Steiner, Beat

    2016-06-10

    In a previous communication we reported on the discovery of aminopyridine 1 as a potent, selective and orally active S1P1 receptor agonist. More detailed studies revealed that this compound is phototoxic in vitro. As a result of efforts aiming at eliminating this undesired property, a series of alkoxy substituted pyridine derivatives was discovered. The photo irritancy factor (PIF) of these alkoxy pyridines was significantly lower than the one of aminopyridine 1 and most compounds were not phototoxic. Focused SAR studies showed, that 2-, 3-, and 4-pyridine derivatives delivered highly potent S1P1 receptor agonists. While the 2-pyridines were clearly more selective against S1PR3, the corresponding 3- or 4-pyridine analogues showed significantly longer oral half-lives and as a consequence longer pharmacological duration of action after oral administration. One of the best compounds, cyclopentoxy-pyridine 45b lacked phototoxicity, showed EC50 values of 0.7 and 140 nM on S1PR1 and S1PR3, respectively, and maximally reduced the blood lymphocyte count for at least 24 h after oral administration of 10 mg/kg to Wistar rats.

  4. New approach toward the synthesis of deuterated pyrazolo[1,5-a]pyridines and 1,2,4-triazolo[1,5-a]pyridines

    Directory of Open Access Journals (Sweden)

    Aleksey Yu. Vorob’ev

    2017-05-01

    Full Text Available An efficient and operationally simple synthesis of 7-deuteropyrazolo[1,5-a]pyridine and 7-deutero-1,2,4-triazolo[1,5-a]pyridine derivatives using α-H/D exchange of 1-aminopyridinium cations in basic D2O followed by a 1,3-cycloaddition of acetylenes and nitriles is presented. A high regioselectivity and a high degree of deuterium incorporation were achieved. The procedure was applied for several 4-R-1-aminopyridinium cations (R = H, Me, OMe.

  5. Contributions a L'etude de Dispositifs D'optique Integree

    Science.gov (United States)

    Touam, Tahar

    Cette these contient des contributions a l'etude de deux champs du vaste domaine de l'optique integree. A cet effet, nous avons divise notre travail en deux grandes parties:. Dans une premiere partie, nous traitons le probleme de la realisation d'une nouvelle classe de guides d'onde planaires utilisables dans le domaine de longueur d'onde de l'infrarouge moyen (infrarouge thermique), domaine ou l'apparition anticipee de fibres optiques a pertes extremement faibles rendraient fort interessante l'existence de tels guides d'onde planaires. Dans un premier temps, nous presentons une etude analytique originale d'une structure planaire a profil d'indice gradue, suivie d'une analyse d'un guide canal base sur cette structure. Dans un deuxieme temps, nous decrivons le procede de fabrication par pulverisation atomique d'un guide planaire forme d'arseniure de gallium (AsGa) sur du dioxyde de silicium (SiO_2 ), combinaison de materiau compatible avec l'infrarouge moyen. Finalement, nous presentons une etude de conception d'un reseau de surface destine a coupler la lumiere dans un tel guide, les autres methodes traditionnelles de couplage semblant peu appropriees aux environs de lambda = 10 mum. Dans une deuxieme partie, nous traitons le probleme de la jonction Y en optique integree, jonction qui soufre de pertes tres importantes des que l'angle d'ouverture devient interessant pour le concepteur de circuits integres optiques. L'analyse est basee sur la methode numerique dite BPM (Beam Propagation Method; methode de propagation du faisceau) qui fait l'objet d'un bref rappel. Nous poursuivons avec l'etude et l'optimisation d'une nouvelle jonction Y dont l'essence est l'utilisation du phenomene de diffraction a travers trois fentes de phase. Nous obtenons ainsi une tres bonne jonction, separant proprement le faisceau, a une ouverture de 10 degres. Finalement, nous faisons un rappel d'un profil d'indice dit "ideal" pour guides courbes et nous proposons l'utilisation de tels guides

  6. Bio-metric study of pig karyotype; Etude biometrique du caryotype du porc

    Energy Technology Data Exchange (ETDEWEB)

    Haag, J.; Lacourly, N.; Nizza, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    This study has a twofold purpose, the former is to determine the swine karyotype as accurately as possible, the latter is to try and develop a method of automatic classification and to show its possibilities and limits. (authors) [French] Cette etude a un double objet: d'une part, de definir de la facon aussi precise que possible le caryotype du porc et d'autre part, de tenter une methode de classification automatique et d'en montrer les possibilites ainsi que les limites. (auteurs)

  7. The maximum water storage capacities in nominally anhydrous minerals in the mantle transition zone and lower mantle

    Science.gov (United States)

    Inoue, T.; Yurimoto, H.

    2012-12-01

    Water is the most important volatile component in the Earth, and affects the physicochemical properties of mantle minerals, e.g. density, elastic property, electrical conductivity, thermal conductivity, rheological property, melting temperature, melt composition, element partitioning, etc. So many high pressure experiments have been conducted so far to determine the effect of water on mantle minerals. To clarify the maximum water storage capacity in nominally anhydrous mantle minerals in the mantle transition zone and lower mantle is an important issue to discuss the possibility of the existence of water reservoir in the Earth mantle. So we have been clarifying the maximum water storage capacity in mantle minerals using MA-8 type (KAWAI-type) high pressure apparatus and SIMS (secondary ion mass spectroscopy). Upper mantle mineral, olivine can contain ~0.9 wt% H2O in the condition just above 410 km discontinuity in maximum (e.g. Chen et al., 2002; Smyth et al., 2006). On the other hand, mantle transition zone mineral, wadsleyite and ringwoodite can contain significant amount (about 2-3 wt.%) of H2O (e.g. Inoue et al., 1995, 1998, 2010; Kawamoto et al., 1996; Ohtani et al., 2000). But the lower mantle mineral, perovskite can not contain significant amount of H2O, less than ~0.1 wt% (e.g. Murakami et al., 2002; Inoue et al., 2010). In addition, garnet and stishovite also can not contain significant amount of H2O (e.g. Katayama et al., 2003; Mookherjee and Karato, 2010; Litasov et al., 2007). On the other hand, the water storage capacities of mantle minerals are supposed to be significantly coupled with Al by a substitution with Mg2+, Si4+ or Mg2+ + Si4+, because Al3+ is the trivalent cation, and H+ is the monovalent cation. To clarify the degree of the substitution, the water contents and the chemical compositions of Al-bearing minerals in the mantle transition zone and the lower mantle were also determined in the Al-bearing systems with H2O. We will introduce the

  8. Ionization of pyridine: Interplay of orbital relaxation and electron correlation

    Science.gov (United States)

    Trofimov, A. B.; Holland, D. M. P.; Powis, I.; Menzies, R. C.; Potts, A. W.; Karlsson, L.; Gromov, E. V.; Badsyuk, I. L.; Schirmer, J.

    2017-06-01

    The valence shell ionization spectrum of pyridine was studied using the third-order algebraic-diagrammatic construction approximation scheme for the one-particle Green's function and the outer-valence Green's function method. The results were used to interpret angle resolved photoelectron spectra recorded with synchrotron radiation in the photon energy range of 17-120 eV. The lowest four states of the pyridine radical cation, namely, 2A2(1 a2 -1), 2A1(7 a1 -1), 2B1(2 b1 -1), and 2B2(5 b2 -1), were studied in detail using various high-level electronic structure calculation methods. The vertical ionization energies were established using the equation-of-motion coupled-cluster approach with single, double, and triple excitations (EOM-IP-CCSDT) and the complete basis set extrapolation technique. Further interpretation of the electronic structure results was accomplished using Dyson orbitals, electron density difference plots, and a second-order perturbation theory treatment for the relaxation energy. Strong orbital relaxation and electron correlation effects were shown to accompany ionization of the 7a1 orbital, which formally represents the nonbonding σ-type nitrogen lone-pair (nσ) orbital. The theoretical work establishes the important roles of the π-system (π-π* excitations) in the screening of the nσ-hole and of the relaxation of the molecular orbitals in the formation of the 7a1(nσ)-1 state. Equilibrium geometric parameters were computed using the MP2 (second-order Møller-Plesset perturbation theory) and CCSD methods, and the harmonic vibrational frequencies were obtained at the MP2 level of theory for the lowest three cation states. The results were used to estimate the adiabatic 0-0 ionization energies, which were then compared to the available experimental and theoretical data. Photoelectron anisotropy parameters and photoionization partial cross sections, derived from the experimental spectra, were compared to predictions obtained with the continuum

  9. Stepwise modification of titanium alkoxy chloride compounds by pyridine carbinol.

    Science.gov (United States)

    Boyle, Timothy J; Ottley, Leigh Anna M; Rodriguez, Mark A; Sewell, Robin M; Alam, Todd M; McIntyre, Sarah K

    2008-11-17

    The stepwise modifications of stoichiometric mixtures of titanium chloride (TiCl 4) and titanium iso-propoxide (Ti(OPr (i)) 4) by 2-pyridine methanol (H-OPy) led to the isolation of a systematically varied, novel family of compounds. The 3:1 reaction mixture of Ti(OPr (i)) 4:TiCl 4 yielded [Cl(OPr (i)) 2Ti(mu-OPr (i))] 2 ( 1). Modification of 1 with 1 and 2 equiv of H-OPy produced [Cl(OPr (i)) 2Ti(mu c-OPy)] 2 ( 2, where mu c = chelating bridge) and "(OPy) 2TiCl(OPr (i))" ( 3, not crystallographically characterized), respectively. Altering the Ti(OPr (i)) 4 to TiCl 4 stoichiometry to 1:1 led to isolation and identification of another dimeric species [Cl 2(OPr (i))Ti(mu-OPr (i))] 2 ( 4). Upon modification with 1 equiv of H-OPy, [Cl 2(OPr (i))Ti(mu c-OPy)] 2 ( 5) was isolated from toluene and (OPy)TiCl 2(OPr (i))(py) ( 6) from py. An additional equivalent of H-OPy led to the monomeric species (OPy) 2TiCl 2 ( 7). Because of the low solubility and similarity in constructs of these compounds, additional analytical data, such as the beryllium dome or BeD-XRD powder analyses, were used to verify the bulk samples, which were found to be in agreement with the single crystal structures.

  10. Deglycosylation of chondroitin sulfate proteoglycan by hydrogen fluoride in pyridine.

    Science.gov (United States)

    Olson, C A; Krueger, R; Schwartz, N B

    1985-04-01

    The original deglycosylation procedure using HF/pyridine has been modified for maximal removal of carbohydrate from chondroitin sulfate proteoglycan, with minimal alteration of the core protein. Gas-liquid chromatography analysis after treatment for various times showed that 95% of xylose and mannose and 70-85% of other sugars were removed within 30 min, indicating that almost all chondroitin sulfate chains and about 80% of N- and O-linked oligosaccharides were removed. In contrast to the loss of carbohydrate, no change in amino acid composition or loss of immunoreactivity occurred. Longer treatment of up to 16 h resulted in little additional removal of carbohydrate, but did cause a significant decrease in solubility and recovery of the deglycosylated product. Optimal removal of xylose residues after about 1 h was also shown by maximal acceptor activity of the product in a xylosyltransferase assay. Rapid removal of the HF reagent by vacuum evacuation and ion-exchange chromatography, coupled with the reduced time of treatment allowed recovery of an intact, homogenous protein core that is amenable to structural and sequence studies.

  11. Synthesis and Microbial Studies of New Pyridine Derivatives-Ⅲ

    Institute of Scientific and Technical Information of China (English)

    PATEL,N.B.; AGRAVAT,S. N.

    2007-01-01

    2-Amino substituted benzothiazole 4a-41 and p-acetamidobenzenesulfonyl chloride 2 were used to prepare 2-(p-aminophenylsulfonamido) substituted benzothiazole 6a-61 using mixture of pyridine and acetic anhydride which formed an electrophilic complex (N-acetyl pyridinium) to facilitate condensation to give desired product by removal of HCl. 2-{p-[(3-Carboxypyrid-2-yl)amino]phenylsulfonamido}benzothiazoles 8a-81 were synthesized from 2-chloropyridine-3-carboxylic acid 7 and 6a-61 in 2-ethoxy ethanol using Cu-powder and K2CO3. Acid chlorides 9a-91 were condensed with 2-hydroxyethyl piperazine 10 and 2,3-dichloropiperazine 11 for amide derivatives 2-(p-((3-(4-(2-hydroxyethyl)piperazin-1-ylcarbonyl)pyrid-2-yl)amino)phenylsulfonamido)benzothiazoles 12a -121 and 2-{p-[3-(2,3-dichloropiperazin-1-ylcarbonyl)pyrid-2-ylamino]phenylsulfonamido}benzothiazoles 13a-131 respectively. The structures of the new compounds have been established on the basis of their chemical analysis and spectral data (IR, 1H NMR and mass). All the compounds have been screened for their antibacterial and antifungal activities.

  12. 无水氯化锶的制备工艺研究%Preparation Technology of Anhydrous Strontium Chloride

    Institute of Scientific and Technical Information of China (English)

    邹兴武; 王树轩; 杨占寿; 王舒娅; 祁米香

    2012-01-01

    依托青海锶资源优势,以次等品碳酸锶和工业盐酸为原料,制备了无水氯化锶.并对除钡、除铁、除硫、脱水干燥等工艺进行了研究.产品能达到一般工业品的要求.氯化锶的制备不仅丰富我省锶产品的种类,而且增加了锶资源企业的抗风险能力.%Relying on the advantage of Qinghai strontium resources, the anhydrous strontium chloride was prepared by low-grade strontium carbonate and industrial hydrochloric acid. The process of removal of barium, sulfur and other impurities from low-grade strontium carbonate was studied,and evaporation,concentration , crystallization, filtering and drying processes were also investigated. The quality of products can reach the requirements of the general industrial. Preparation of strontium chloride, not only enrich the types of strontium products in Qinghai province,but also increase the ability of resiting risk of Strontium production enterprises.

  13. Reactive Precipitation of Anhydrous Alkali Sulfide Nanocrystals with Concomitant Abatement of Hydrogen Sulfide and Cogeneration of Hydrogen.

    Science.gov (United States)

    Li, Xuemin; Zhao, Yangzhi; Brennan, Alice; McCeig, Miranda; Wolden, Colin A; Yang, Yongan

    2017-07-21

    Anhydrous alkali sulfide (M2 S, M=Li or Na) nanocrystals (NCs) are important materials central to the development of next generation cathodes and solid-state electrolytes for advanced batteries, but not commercially available at present. This work reports an innovative method to directly synthesize M2 S NCs through alcohol-mediated reactions between alkali metals and hydrogen sulfide (H2 S). In the first step, the alkali metal is complexed with alcohol in solution, forming metal alkoxide (ROM) and releasing hydrogen (H2 ). Next, H2 S is bubbled through the ROM solution, where both chemicals are completely consumed to produce phase-pure M2 S NC precipitates and regenerate alcohol that can be recycled. The M2 S NCs morphology may be tuned through the choice of the alcohol and solvent. Both synthetic steps are thermodynamically favorable (ΔGm(o) <-100 kJ mol(-1) ), proceeding rapidly to completion at ambient temperature with almost 100 % atom efficiency. The net result, H2 S+2 m→M2 S+H2 , makes good use of a hazardous chemical (H2 S) and delivers two value-added products that naturally phase separate for easy recovery. This scalable approach provides an energy-efficient and environmentally benign solution to the production of nanostructured materials required in emerging battery technologies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Crystal structure of barium perchlorate anhydrate, Ba(ClO42, from laboratory X-ray powder data

    Directory of Open Access Journals (Sweden)

    Jeonghoo H. Lee

    2015-06-01

    Full Text Available The previously unknown crystal structure of barium perchlorate anhydrate, determined and refined from laboratory X-ray powder diffraction data, represents a new structure type. The title compound was obtained by heating hydrated barium perchlorate [Ba(ClO42·xH2O] at 423 K in vacuo for 6 h. It crystallizes in the orthorhombic space group Fddd. The asymmetric unit contains one Ba (site symmetry 222 on special position 8a, one Cl (site symmetry 2 on special position 16f and two O sites (on general positions 32h. The structure can be described as a three-dimensional polyhedral network resulting from the corner- and edge-sharing of BaO12 polyhedra and ClO4 tetrahedra. Each BaO12 polyhedron shares corners with eight ClO4 tetrahedra, and edges with two ClO4 tetrahedra. Each ClO4 tetrahedron shares corners with four BaO12 polyhedra, and an edge with the other BaO12 polyhedron.

  15. Kinetics study of pyridine biodegradation by a novel bacterial strain, Rhizobium sp. NJUST18.

    Science.gov (United States)

    Shen, Jinyou; Zhang, Xin; Chen, Dan; Liu, Xiaodong; Zhang, Libin; Sun, Xiuyun; Li, Jiansheng; Bi, Huiping; Wang, Lianjun

    2014-06-01

    Biodegradation of pyridine by a novel bacterial strain, Rhizobium sp. NJUST18, was studied in batch experiments over a wide concentration range (from 100 to 1,000 mg l(-1)). Pyridine inhibited both growth of Rhizobium sp. NJUST18 and biodegradation of pyridine. The Haldane model could be fitted to the growth kinetics data well with the kinetic constants μ* = 0.1473 h(-1), K s = 793.97 mg l(-1), K i = 268.60 mg l(-1) and S m = 461.80 mg l(-1). The true μ max, calculated from μ*, was found to be 0.0332 h(-1). Yield coefficient Y X/S depended on S i and reached a maximum of 0.51 g g(-1) at S i of 600 mg l(-1). V max was calculated by fitting the pyridine consumption data with the Gompertz model. V max increased with initial pyridine concentration up to 14.809 mg l(-1) h(-1). The q S values, calculated from [Formula: see text], were fitted with the Haldane equation, yielding q Smax = 0.1212 g g(-1) h(-1) and q* = 0.3874 g g(-1) h(-1) at S m' = 507.83 mg l(-1), K s' = 558.03 mg l(-1), and K i' = 462.15 mg l(-1). Inhibition constants for growth and degradation rate value were in the same range. Compared with other pyridine degraders, μ max and S m obtained for Rhizobium sp. NJUST18 were relatively high. High K i and K i' values and extremely high K s and K s' values indicated that NJUST18 was able to grow on pyridine within a wide concentration range, especially at relatively high concentrations.

  16. Solid Phase Synthesis of Anhydrous Zinc Borate from Zinc and Boron Oxide and Utilization as a Flame Retardant in Dye and Textile

    OpenAIRE

    AYAR, Barış; GÜRÜ, Metin; ÇAKANYILDIRIM, Çetin

    2014-01-01

    Durability of materials to flame and stability at high temperatures are very important in order to increase the field of use. Non-flammability is not the only requirement materials should not have toxic gas products during the burning, also. Anhydrous zinc borate was chosen as flame retardant due to its advantages, such as; light weight, high melting point, low thermal expansion, and intrinsic smoke suppressant and corrosion resistance properties. For the synthesis, metallic zinc and anhydrou...

  17. The use of anhydrous CeCl{sub 3} as a recyclable and selective catalyst for the acetalization of aldehydes and ketones

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Claudio C.; Mendes, Samuel R.; Ziembowicz, Francieli I. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Dept. de Quimica; Lenardao, Eder J.; Perin, Gelson [Universidade Federal de Pelotas (UFPel), RS (Brazil). Inst. de Quimica e Geociencias

    2010-07-01

    An efficient, clean, chemoselective and solvent-free method for the synthesis of ketone and aldehyde dimethyl acetals was developed using trimethyl orthoformate and commercially available anhydrous CeCl{sub 3} as a recyclable catalyst. The method is general and affords the protected carbonyl compounds in good yields and under mild conditions, including aryl and alkyl ketones and activated aldehydes. The catalyst could be utilised directly for 3 cycles, without significant loss of activity. (author)

  18. Two expedient ‘one-pot’ methods for synthesis of -aryl--mercaptoketones over anhydrous potassium carbonate or amberlyst-15 catalyst

    Indian Academy of Sciences (India)

    Chayan Guha; Rina Mondal; Rammohan Pal; Asok K Mallik

    2013-11-01

    Two expedient one-pot methods have been developed for synthesis of -aryl--mercaptoketones using acetophenones, benzaldehydes and thiols as starting materials. The methods involve microwave irradiation (5min) of 1:1 mixtures of acetophenones and benzaldehydes over neutral alumina supported anhydrous potassium carbonate or amberlyst-15 in the first step, and that is followed by addition of thiol to the resulting material and keeping at room temperature for 1.5 h.

  19. Determining the amount of anhydrous alcohol evaporated in vertical cylindrical tanks; Determinacao da quantidade de alcool etilico anidro evaporado em tanques cilindricos verticais

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Elcio Cruz de [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    In order to assess the anhydrous alcohol evaporated amount in vertical cylindrical tanks was developed a calculation methodology based on the rate of mass transfer of the product, the Reynolds number and the mass transfer coefficient. An Excel spreadsheet was prepared with data entry of the tank and physical and chemical properties of the product (temperature and density). For a temperature of 50 deg C, the volume evaporated reaches values of 0.8% by day. (author)

  20. The influence of excipients on the stability of the moisture sensitive drugs aspirin and niacinamide: comparison of tablets containing lactose monohydrate with tablets containing anhydrous lactose.

    Science.gov (United States)

    Du, J; Hoag, S W

    2001-01-01

    The purpose of this study is to test the hypothesis that in tablet formulations, moisture-sensitive drugs formulated with lactose monohydrate have the same stability as formulations containing anhydrous lactose, and to characterize the kinetics of niacinamide degradation in the solid state. Aspirin and niacinamide decomposition were used as indicators of stability. Aspirin and niacinamide tablets containing either lactose monohydrate or anhydrous lactose were separately investigated at different temperatures and relative humidities; the stability tests were done at 25 degrees C--60% RH, 40 degrees C--80% RH, 60 degrees C--60% RH, 60 degrees C--80% RH, and 80 degrees C--80% RH. Official U.S. Pharmacopeia methods were used for the aspirin and niacinamide assays. Statistical analysis showed that tablets containing lactose monohydrate have the same stability as tablets containing anhydrous lactose, which means that even though water is present in the crystal structure, the bound water does not influence the reaction rate. In addition, niacinamide degradation in the solid-state can be described by a third order rate equation.

  1. Lower Nitrous Oxide Emissions from Anhydrous Ammonia Application Prior to Soil Freezing in Late Fall Than Spring Pre-Plant Application.

    Science.gov (United States)

    Tenuta, Mario; Gao, Xiaopeng; Flaten, Donald N; Amiro, Brian D

    2016-07-01

    Fall application of anhydrous ammonia in Manitoba is common but its impact on nitrous oxide (NO) emissions is not well known. A 2-yr study compared application before freeze-up in late fall to spring pre-plant application of anhydrous ammonia on nitrous oxide (NO) emissions from a clay soil in the Red River Valley, Manitoba. Spring wheat ( L.) and corn ( L.) were grown on two 4-ha fields in 2011 and 2012, respectively. Field-scale flux of NO was measured using a flux-gradient micrometeorological approach. Late fall treatment did not induce NO emissions soon after application or in winter likely because soil was frozen. Application time did alter the temporal pattern of emissions with late fall and spring pre-plant applications significantly increasing median daily NO flux at spring thaw and early crop growing season, respectively. The majority of emissions occurred in early growing season resulting in cumulative emissions for the crop year being numerically 33% less for late fall than spring pre-plant application. Poor yield in the first year with late fall treatment occurred because of weed and volunteer growth with delayed planting. Results show late fall application of anhydrous ammonia before freeze-up increased NO emissions at thaw and decreased emissions for the early growing season compared to spring pre-plant application. However, improved nitrogen availability of late fall application to crops the following year is required when planting is delayed because of excessive moisture in spring.

  2. Anhydrate to hydrate solid-state transformations of carbamazepine and nitrofurantoin in biorelevant media studied in situ using time-resolved synchrotron X-ray diffraction

    DEFF Research Database (Denmark)

    Bøtker, Johan Peter; Rantanen, Jukka; Arnfast, Lærke

    2016-01-01

    with different biorelevant media, simulated fasted and fed state intestinal fluids containing bile salt and dioleoylphosphatidylcholine (DOPC) micelles, DOPC/sodium dodecyl sulfate (SDS) mixture, bile salt solution and water. Two anhydrate compounds (carbamazepine, CBZ and nitrofurantoin, NF) with different......Abstract Transformation of the solid-state form of a drug compound in the lumen of the gastrointestinal tract may alter the drug bioavailability and in extreme cases result in patient fatalities. The solution-mediated anhydrate-to-hydrate phase transformation was examined using an in vitro model...... analysis, PCA) and compared to those for nitrofurantoin (NF). The study showed that the solution-mediated phase transformation of CBZ anhydrate was remarkably faster in the DOPC/SDS medium compared to transformation in all the other aqueous dispersion media. The conversion time for CBZ anhydrate in water...

  3. Synthesis and antibacterial activity against ralstonia solanacearum for novel hydrazone derivatives containing a pyridine moiety

    Directory of Open Access Journals (Sweden)

    Wu Jian

    2012-04-01

    Full Text Available Abstract Background Ralstonia solanacearum, one of the most important bacterial diseases on plants, is a devastating, soil-borne plant pathogen with a global distribution and an unusually wide host range. In order to discover new bioactive molecules and pesticides acting on tobacco bacterial wilt, we sought to combine the active structure of hydrazone and pyridine together to design and synthesize a series of novel hydrazone derivatives containing a pyridine moiety. Results A series of hydrazone derivatives containing a pyridine moiety were synthesized. Their structures were characterized by 1 H-NMR, 13 C-NMR, IR, and elemental analysis. The preliminary biological activity tests showed that compound 3e and 3g exhibited more than 80% activity against Ralstonia solanacearum at 500 mg/L, especially compound 3g displayed relatively good activity to reach 57.0% at 200 mg/L. Conclusion A practical synthetic route to hydrazone derivatives containing a pyridine moiety by the reaction of intermediates 2 with different aldehydes in ethanol at room temperature using 2-chloronicotinic acid and 2-amino-5-chloro-3-methylbenzoic acid as start materials is presented. This study suggests that the hydrazone derivatives containing a substituted pyridine ring could inhibit the growth of Ralstonia solanacearum.

  4. Formation of BH3 Adducts with Pyridine-2-Methylaminophosphine ligands: An experimental and computational study

    Indian Academy of Sciences (India)

    Harinath Adimulam; Dwijendra P Kukri; Bhabani S Mallik; Tarun K Panda

    2016-01-01

    The reaction of pyridine-2-methylaminophosphine [C5H4N-CH2NHPPh2] (1) and pyridine-2-methylphosphinoselenoic amide [C5H4N-CH2NHP(Se)Ph2] (2) with BH3·SMe2 yields the corresponding adducts [C5H4N(BH3)-CH2NHP(BH3)Ph2] (1a), and [C5H4N(BH3)-CH2NHP(Se)Ph2] (2a), respectively. The solid state structures of both the compounds were established by single crystal X-ray diffraction analysis. The phosphorus and the pyridine nitrogen atoms are coordinated to the boron atom in the case of 1a whereas only pyridine nitrogen atom is attached to the BH3 group in the case of 2a. To understand the nature of P-B/ N-B bonds and to compare the basicities of pyridine nitrogen, amino nitrogen and phosphorus atoms, density functional theoretical (DFT) calculations were performed on the BH3 adducts 1a and 2a. The results are consistent with the experimental results.

  5. Pyridine coordination chemistry for molecular assemblies on surfaces.

    Science.gov (United States)

    de Ruiter, Graham; Lahav, Michal; van der Boom, Milko E

    2014-12-16

    CONSPECTUS: Since the first description of coordination complexes, many types of metal-ligand interactions have creatively been used in the chemical sciences. The rich coordination chemistry of pyridine-type ligands has contributed significantly to the incorporation of diverse metal ions into functional materials. Here we discuss molecular assemblies (MAs) formed with a variety of pyridine-type compounds and a metal containing cross-linker (e.g., PdCl2(PhCN2)). These MAs are formed using Layer-by-Layer (LbL) deposition from solution that allows for precise fitting of the assembly properties through molecular programming. The position of each component can be controlled by altering the assembly sequence, while the degree of intermolecular interactions can be varied by the level of π-conjugation and the availability of metal coordination sites. By setting the structural parameters (e.g., bond angles, number of coordination sites, geometry) of the ligand, control over MA structure was achieved, resulting in surface-confined metal-organic networks and oligomers. Unlike MAs that are constructed with organic ligands, MAs with polypyridyl complexes of ruthenium, osmium, and cobalt are active participants in their own formation and amplify the growth of the incoming molecular layer. Such a self-propagating behavior for molecular systems is rare, and the mechanism of their formation will be discussed. These exponentially growing MAs are capable of storing metal salts that can be used during the buildup of additional molecular layers. Various parameters influencing the film growth mechanism will be presented, including (i) the number of binding sites and geometry of the organic ligands, (ii) the metal and the structure of the polypyridyl complexes, (iii) the influence of the metal cross-linker (e.g., second or third row transition metals), and (iv) the deposition conditions. By systematic variation of these parameters, switching between linear and exponential growth could

  6. The mechanism of unexpected reduction of dimethyl pyridine-2,3-dicarboxylate to 1,2,3,4-tetrahydrofuro[3,4-b]-pyridin-5(7H)-one with sodium borohydride

    Institute of Scientific and Technical Information of China (English)

    Yan Bo Tang; Qing Jian Zhang; De Quan Yu

    2012-01-01

    An unexpected reduction of dimethyl pyridine-2,3-dicarboxylate to 1,2,3,4-tetrahydrofuro[3,4-b]pyridin-5(7H)-one with sodium borohydride in ethanol and tetrahydrofuran,respectively,is described,a hypothetic mechanism for the unusual reductive product is proposed.

  7. Low to Extremely Low Water Abundances Measured in Nominally Anhydrous Minerals in Mafic to Granitic Apollo Rock Clasts

    Science.gov (United States)

    Simon, J. I.; Christoffersen, R.; Wang, J.; Alexander, C. M. O'D.; Mills, R. D.; Hauri, E. H.

    2017-01-01

    Lunar sample-based volatile studies have focused on assessing the inventory and distribution of water in the Moon. Some have focused on the relatively young mare basalts and pyroclastic glasses, which result from partial melting of the relatively young lunar mantle. Less certain is the water inventory for the oldest materials available, which have the greater potential to record the earliest history of volatiles in the Moon (and thus provide evidence for the "wet" vs. "dry" accretion hypotheses of the Earth-Moon system. Studies of volatiles in ancient lunar rocks have largely focused on apatite. One recent FTIR (Fourier Transform Infrared Radiometer) study of plagioclase reported a relatively "wet" (approximately 320 parts per million) magma for primordial ferroan anorthosites (FANs). Another, a NanoSIMS study of alkali feldspar, reported a "wet" (approximately 1 weight percentage) felsic magma, but due to the differentiation processes required for silicic magmatism in the lunar crust, predicted an essentially "dry" (less than 100 parts per million) bulk Moon. Thus, despite evidence that appears to complicate the early "dry" Moon paradigm, there is no apparent unanimity among the measurements, even those on apatite. This disparity is clearly seen by the order of magnitude different water estimates for lunar "alkali-rich suite rocks" (Fig. 1). Some of the apparent differences may be explained by recent improvements in the apatite-based water estimates that better account for relative compatibilities of OH-, Cl, and F. In the present work, we seek to expand our understanding of the volatile abundances in early formed lunar magmas, their source reservoirs, and to address the potential role that felsic magmas play on the lunar hydrogen budget over time by employing NanoSIMS analysis of nominally anhydrous minerals.

  8. Efficient post-processing of aqueous generator eluates facilitates {sup 68}Ga-labelling under anhydrous conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zoller, F.; Riss, P.J.; Roesch, F. [University of Mainz (Germany). Institute of Nuclear Chemistry; Montforts, F.P. [University of Bremen (Germany). Institute of Organic Chemistry

    2010-07-01

    The present study reports a convenient method for {sup 68}Ga-labelling under anhydrous conditions using solid-phase derived gallium-68-acetylacetonate ([ {sup 68}Ga]Ga(acac){sub 3}) in a microwave-enhanced radiosynthesis. Commercial {sup 68}Ge/{sup 68}Ga-radionuclide generators utilizing TiO{sub 2} to adsorb {sup 68}Ge(IV) (Obninsk-generators) were used. The initial aqueous generator eluate was transferred online onto a cation exchange resin and {sup 68}Ga was absorbed quantitatively. From this resin, {sup 68}Ga was eluted with different acetone-based, non-aqueous solvent systems. More than 95% of the generator-eluted {sup 68}Ga was obtained from the cation exchange resin with 600 {mu}L of a 98% acetone/2% acetylacetone mixture providing n.c.a. [ {sup 68}Ga]Ga(acac){sub 3} as labelling agent. Water-insoluble macrocyclic polypyrrole derivatives were chosen as model compounds for a proof-of-principle labelling of lipophilic compounds with {sup 68}Ga. Labelling of two different porphyrin derivatives, meso -tetraphenyl-porphyrin (Tpp) and 3-(1-hydroxyheptyl)deuteroporphyrin dimethylester (HHDPD) was performed in chloroform in a focused microwave synthesis system in yields of up to 90% within 5 min using phenol as co-ligand. Moreover, new co-ligands were investigated to be more effective and significantly less toxic than phenol. Among the phenol alternatives, gentisic acid (2,5-dihydroxy benzoic acid, DHB, 5 mg) emerged as the most useful, non-toxic phenol substitute. It facilitates reducing the load of co-ligand by 95%, while providing an increased labeling yield of 97%. {sup 68}Ga-labelled porphyrins may facilitate the medical application for molecular imaging via positron emission tomography. (orig.)

  9. C-H activation of ethers by pyridine tethered PCsp3P-type iridium complexes.

    Science.gov (United States)

    Cui, Peng; Babbini, Dominic C; Iluc, Vlad M

    2016-06-14

    Iridium PCsp3P complexes featuring a novel bis(2-diphenylphosphinophenyl)-2-pyridylmethane ligand (PC(Py)HP) are reported. C-H activation reactions between the dihydride complex [(PC(Py)P)Ir(H)2] and tetrahydrofuran or methyl tert-butyl ether in the presence of a hydrogen acceptor, norbornene (NBE), at ambient temperature led exclusively to the hydrido oxyalkyl complexes, [(PC(Py)P)IrH(C4H7O)] and [(PC(Py)P)IrH(CH2O(t)Bu)], respectively. The internal pyridine donor is important and stabilizes these species by coordination to the iridium center. The coordination of pyridine to the iridium center is labile, however, and its dissociation occurs in the presence of a suitable substrate, as demonstrated by the intramolecular nucleophilic attack of pyridine on a vinylidene intermediate generated from PhC[triple bond, length as m-dash]CH.

  10. 3,5-Bis[(pyridin-4-ylmethoxy]benzoic acid

    Directory of Open Access Journals (Sweden)

    Hong Lin

    2013-01-01

    Full Text Available Single crystals of the title compound, C19H16N2O4, were obtained under hydrothermal conditions by an unintended recrystallization of the employed microcrystalline starting material. The [(pyridin-4-ylmethoxy]benzoic acid unit is nearly planar, with a maximum deviation from the least-squares plane of 0.194 (2 Å. This plane is inclined by 35.82 (6° to that defined by the second (pyridin-4-ylmethoxy group [in which the largest deviation from the least-squares plane is 0.013 (2 Å]. In the crystal, molecules are linked by O—H...N hydrogen bonds involving the acid hydroxy group and a pyridine N atom into chains parallel to [-201].

  11. Dibromidobis{1-[4-(pyridin-4-ylphenyl]ethanone-κN}mercury(II

    Directory of Open Access Journals (Sweden)

    Wen-Shen Zhang

    2011-12-01

    Full Text Available In the title compound, [HgBr2(C13H11NO2], the HgII atom adopts a four-coordinated HgN2Br2 geometry, formed by two pyridine N atoms from two ligands and two bromide anions. The complex is located on a twofold axis. The coordination geometry is close to forming a see-saw (SS-4 polyhedron, the symmetry-related organic ligands being almost perpendicular; the dihedral angles between the two pyridine rings and between the two benzene rings are 85.5 (4 and 87.7 (4°, respectively. Within the organic ligand, the pyridine ring is nearly coplanar with the benzene ring [dihedral angle = 13.1 (8°]. In the crystal, the molecular complexes are connected through weak intermolecular C—H...Br contacts.

  12. Synthesis and antituberculosis activity of indole-pyridine derived hydrazides, hydrazide-hydrazones, and thiosemicarbazones.

    Science.gov (United States)

    Velezheva, Valeriya; Brennan, Patrick; Ivanov, Pavel; Kornienko, Albert; Lyubimov, Sergey; Kazarian, Konstantin; Nikonenko, Boris; Majorov, Konstantin; Apt, Alexander

    2016-02-01

    We describe the design, synthesis, and in vitro antimycobacterial activity of a series of novel simple hybrid hydrazides and hydrazide-hydrazones combining indole and pyridine nuclei. The compounds are derivatives of 1-acetylindoxyl or substituted indole-3-carboxaldehydes tethered via a hydrazine group by simple C-N or double C=N bonds with 3- and 4-pyridines, 1-oxide 3- and 4-pyridine carbohydrazides. The most active of 15 compounds showed MICs values against an INH-sensitive strain of Mycobacterium tuberculosis H37Rv equal to that of INH (0.05-2 μg/mL). Five compounds demonstrated appreciable activity against the INH-resistant M. tuberculosis CN-40 clinical isolate (MICs: 2-5 μg/mL), providing justification for further in vivo studies.

  13. Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium.

    Science.gov (United States)

    El Ashry, El Sayed H; El Nemr, Ahmed; Ragab, Safaa

    2012-03-01

    Quantum chemical calculations using the density functional theory (B3LYP/6-31G DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E (HOMO)), energy of lowest unoccupied molecular orbital (E (LUMO)) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.

  14. Nickel(2) complexes of cyclen- and cyclam-pyridine: topological reorganizations induced by electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Sanae, El Ghachtouli; Cadiou, C.; Dechamps-Olivier, I.; Chuburu, F.; Aplincourt, M. [Reims Champagne-Ardenne Univ., GRECI, 51 (France); Patinec, V.; Le Baccon, M.; Handel, H. [Universite de Bretagne Occidentale, Chimie, Electrochimie moleculaires et chimie analytique, UMR CNRS 6521, CS 93837, 29 - Brest (France); Roisnel, Th. [Institut de Chimie de Rennes, UMR CNRS 6511, CS 74205, 35 - Rennes (France)

    2006-03-15

    The Ni(II) complexes of cyclen- and cyclam-pyridine (respectively 1-pyridine-2-ylmethyl-1,4,7,10-tetra-aza-cyclo-dodecane and 1-pyridine-2-ylmethyl-1,4,8,11-tetra-aza-cyclo-tetra-decane denoted [Ni(II)L(1)]{sup 2+} and [Ni(II)L(2)]{sup 2+}) have been isolated and characterised by X-ray diffraction, UV-visible spectroscopy and electrochemical studies for the [Ni(II)L(2)]{sup 2+} complex. In particular, the [Ni(II)L(2)]{sup 2+} complex adopts two distinct and stable geometries (type I and V), which mainly differ by the macrocycle configuration. In solution, the isomerization process between these two configurations is driven by the nickel-centered electron transfer. (authors)

  15. Hydrogen bonded complexes of cyanuric acid with pyridine and guanidinium carbonate

    Indian Academy of Sciences (India)

    K Sivashankar

    2000-12-01

    Hydrogen bonded complexes of cyanuric acid (CA) with pyridine, [C3N3H3O3:C5H5N], 1, and guanidinium carbonate [C3H2N3][C(NH2)3], 2, have been prepared at room temperature and characterized by single-crystal X-ray diffraction. Structure of 1 shows pyridine molecules substituting the inter-tape hydrogen bond in CA by N-H…N and C-H…O hydrogen bonds. The structure reveals CA-pyridine hydrogen-bonded single helices held together by dimeric N-H…O hydrogen bonding between CA molecules. In 2, the CA tapes, resembling a sine wave interact with the guanidinium cations through N-H…O and N-H…N hydrogen bonds forming guanidinium cyanurate sheets.

  16. Thieno[2,3-b]pyridines--a new class of multidrug resistance (MDR) modulators.

    Science.gov (United States)

    Krauze, Aivars; Grinberga, Signe; Krasnova, Laura; Adlere, Ilze; Sokolova, Elina; Domracheva, Ilona; Shestakova, Irina; Andzans, Zigmars; Duburs, Gunars

    2014-11-01

    To identify new potent multidrug resistance modulators, we have synthesized a series of novel thieno[2,3-b]pyridines and furo[2,3-b]pyridines, and examined their structure-activity relationships. All synthesized compounds were tested to determine BCRP1, P-gp, and MRP1 inhibitor activity, and most potent MDR modulators were also screened for their toxicity, cytotoxicity and Ca(2+) channel antagonist activity. Among these compounds, thieno[2,3-b]pyridine (6r) was found to exhibit a potent P-gp inhibitory action with EC50 = 0.3 ± 0.2 μM, MRP1 inhibitory action with EC50 = 1.1 ± 0.1 μM and BCRP1 inhibitory action with EC50 = 0.2 ± 0.05 μM and may represent suitable candidate for further pharmacological studies.

  17. pH-responsive fluorescence chemical sensor constituted by conjugated polymers containing pyridine rings.

    Science.gov (United States)

    Adachi, Naoya; Kaneko, Yuki; Sekiguchi, Kazuki; Sugiyama, Hiroki; Sugeno, Masafumi

    2015-12-01

    Poly(p-pyridinium phenylene ethynylene)s (PPyPE) functionalized with alternating donor-acceptor repeat units were synthesized by a Pd-catalyzed Sonogashira coupling reaction between diethynyl monomer and di-iodopyridine for use as a pH-responsive fluorescence chemical sensor. The synthesized PPyPE, containing pyridine units, was characterized by FT-IR, (1)H and (13)C NMR, UV-visible and fluorescence spectroscopies. We investigated the relationship between changes of optical properties and protonation/deprotonation of PPyPE containing pyridine units in solution. Addition of HCl decreased and red-shifted the fluorescence intensity of the conjugated polymers that contained pyridine rings; fluorescence intensity of the polymers increased upon addition of NaOH solution. The synthesized PPyPE was found to be an effective and reusable chemical sensor for pH sensing.

  18. Can A Denaturant Stabilize DNA? Pyridine Reverses DNA Denaturation in Acidic pH.

    Science.gov (United States)

    Portella, Guillem; Terrazas, Montserrat; Villegas, Núria; González, Carlos; Orozco, Modesto

    2015-09-01

    The stability of DNA is highly dependent on the properties of the surrounding solvent, such as ionic strength, pH, and the presence of denaturants and osmolytes. Addition of pyridine is known to unfold DNA by replacing π-π stacking interactions between bases, stabilizing conformations in which the nucleotides are solvent exposed. We show here experimental and theoretical evidences that pyridine can change its role and in fact stabilize the DNA under acidic conditions. NMR spectroscopy and MD simulations demonstrate that the reversal in the denaturing role of pyridine is specific, and is related to its character as pseudo groove binder. The present study sheds light on the nature of DNA stability and on the relationship between DNA and solvent, with clear biotechnological implications.

  19. A simple and efficient synthesis of imidazolo[1,2-a]pyridines using MgO in aqueous medium

    Directory of Open Access Journals (Sweden)

    S.V. Patil

    2016-11-01

    Full Text Available Various imidazolo[1,2-a]pyridines were synthesized from amino pyridines and aromatic phenacyl bromides by one step process in the presence of MgO in aqueous medium at room temperature. The salient feature of this method includes mild conditions, short reaction time, high yields, easy purification and simple procedure.

  20. Large-Scale Solvent-Free Chlorination of Hydroxy-Pyrimidines, -Pyridines, -Pyrazines and -Amides Using Equimolar POCl3

    Directory of Open Access Journals (Sweden)

    Zhihua Sun

    2012-04-01

    Full Text Available Chlorination with equimolar POCl3 can be efficiently achieved not only for hydroxypyrimidines, but also for many other substrates such as 2-hydroxy-pyridines, -quinoxalines, or even -amides. The procedure is solvent-free and involves heating in a sealed reactor at high temperatures using one equivalent of pyridine as base. It is suitable for large scale (multigram batch preparations.

  1. Structure-Activity Relationships for the 9-(Pyridin-2’-yl- aminoacridines

    Directory of Open Access Journals (Sweden)

    Katherine S. Frost

    2004-02-01

    Full Text Available A series of 9-(pyridin-2’-yl-aminoacridines was prepared and analyzed for their ability to change the thermal denaturation temperature of genomic calf thymus DNA. Development of a QSAR equation indicated that electron withdrawing groups on the pyridine ring promoted the interaction with double stranded DNA.

  2. Biosynthesis inspired Diels-Alder route to pyridines: synthesis of the 2,3-dithiazolylpyridine core of the thiopeptide antibiotics.

    Science.gov (United States)

    Moody, Christopher J; Hughes, Rachael A; Thompson, Stewart P; Alcaraz, Lilian

    2002-08-21

    Reaction of serine derived 1-alkoxy-2-azadienes with dehydroalanine derived dienophiles results in Diels-Alder reaction and aromatisation to give 2,3,6-trisubstituted pyridines, thereby establishing the viability of the proposed biosynthetic route to the pyridine ring of the thiopeptide antibiotics originally proposed by Bycroft and Gowland.

  3. Profiles of the biosynthesis and metabolism of pyridine nucleotides in potatoes (Solanum tuberosum L.).

    Science.gov (United States)

    Katahira, Riko; Ashihara, Hiroshi

    2009-12-01

    As part of a research program on nucleotide metabolism in potato tubers (Solanum tuberosum L.), profiles of pyridine (nicotinamide) metabolism were examined based on the in situ metabolic fate of radio-labelled precursors and the in vitro activities of enzymes. In potato tubers, [(3)H]quinolinic acid, which is an intermediate of de novo pyridine nucleotide synthesis, and [(14)C]nicotinamide, a catabolite of NAD, were utilised for pyridine nucleotide synthesis. The in situ tracer experiments and in vitro enzyme assays suggest the operation of multiple pyridine nucleotide cycles. In addition to the previously proposed cycle consisting of seven metabolites, we found a new cycle that includes newly discovered nicotinamide riboside deaminase which is also functional in potato tubers. This cycle bypasses nicotinamide and nicotinic acid; it is NAD --> nicotinamide mononucleotide --> nicotinamide riboside --> nicotinic acid riboside --> nicotinic acid mononucleotide --> nicotinic acid adenine dinucleotide --> NAD. Degradation of the pyridine ring was extremely low in potato tubers. Nicotinic acid glucoside is formed from nicotinic acid in potato tubers. Comparative studies of [carboxyl-(14)C]nicotinic acid metabolism indicate that nicotinic acid is converted to nicotinic acid glucoside in all organs of potato plants. Trigonelline synthesis from [carboxyl-(14)C]nicotinic acid was also found. Conversion was greater in green parts of plants, such as leaves and stem, than in underground parts of potato plants. Nicotinic acid utilised for the biosynthesis of these conjugates seems to be derived not only from the pyridine nucleotide cycle, but also from the de novo synthesis of nicotinic acid mononucleotide.

  4. Vibrational dephasing and frequency shifts of hydrogen-bonded pyridine-water complexes

    Science.gov (United States)

    Kalampounias, A. G.; Tsilomelekis, G.; Boghosian, S.

    2015-01-01

    In this paper we present the picosecond vibrational dynamics and Raman shifts of hydrogen-bonded pyridine-water complexes present in aqueous solutions in a wide concentration range from dense to extreme dilute solutions. We studied the vibrational dephasing and vibrational frequency modulation by calculating time correlation functions of vibrational relaxation by fits in the frequency domain. The concentration induced variations in bandwidths, band frequencies and characteristic dephasing times have been estimated and interpreted as effects due to solute-solvent interactions. The time-correlation functions of vibrational dephasing were obtained for the ring breathing mode of both "free" and hydrogen-bonded pyridine molecules and it was found that sufficiently deviate from the Kubo model. There is a general agreement in the whole concentration range with the modeling proposed by the Rothschild approach, which applies to complex liquids. The results have shown that the reorientation of pyridine aqueous solutions is very slow and hence in both scattering geometries only vibrational dephasing is probed. It is proposed that the spectral changes depend on the perturbations induced by the dynamics of the water molecules in the first hydration cell and water in bulk, while at extreme dilution conditions, the number of bulk water molecules increases and the interchange between molecules belonging to the first hydration cell may not be the predominant modulation mechanism. The evolution of several parameters, such as the characteristic times, the percentage of Gaussian character in the peak shape and the a parameter are indicative of drastic variations at extreme dilution revealing changes in the vibrational relaxation of the pyridine complexes in the aqueous environment. The higher dilution is correlated to diffusion of water molecules into the reference pyridine system in agreement with the jump diffusion model, while at extreme dilutions, almost all pyridine molecules are

  5. Sulfur Dioxide-Pyridine Dimer. FTIR and Theoretical Evidence for a Low-Symmetry Structure.

    Science.gov (United States)

    Keller, John W

    2015-10-15

    Sulfur dioxide-pyridine complex formation was reinvestigated using Fourier transform infrared (FTIR) spectroscopy and computational methods. The SO2-pyridine dimer has been proposed to have a v-shaped, Cs-symmetric structure based on the microwave spectrum; however, recent research showing the occurrence of X···H-C hydrogen bonds in noncovalent complexes suggested that the structure of the complex should be re-examined. The FTIR spectrum of the dimer was obtained by numerical analysis of the spectra of pyridine-SO2 mixtures in CCl4. The spectrum showed ortho C-H stretching modes consistent with a C1-symmetric structure containing a S-O bond oriented approximately coplanar with the pyridine ring and adjacent to an ortho C-H moiety. The C1 structure, which was identified as the global minimum by various density functional theory and correlated ab initio calculations, is also consistent with the out-of-plane second moment (Pbb) value previously determined by microwave spectroscopy. The complex is converted to its mirror image via three possible Cs-symmetric transition states: v-shaped, bisected, and flat. At the M06-2X/6-311++G(2d,p) level of theory, the rotational barriers (ΔG(o‡)) are 1.40, 1.87, and 3.63 kcal mol(-1), respectively. Natural bond order analysis indicated the asymmetric complex is stabilized both by N→S donation and back-donation from O to antibonding orbitals on pyridine. Atoms in molecules calculations identified a bond critical point within the O···H-C gap consistent with a normal, albeit weak, hydrogen bond. Theoretical studies also identified a high-energy sandwich-type dimer with Cs symmetry, and a C2-symmetric SO2-pyridine2 trimer.

  6. Vibrational dephasing and frequency shifts of hydrogen-bonded pyridine-water complexes.

    Science.gov (United States)

    Kalampounias, A G; Tsilomelekis, G; Boghosian, S

    2015-01-25

    In this paper we present the picosecond vibrational dynamics and Raman shifts of hydrogen-bonded pyridine-water complexes present in aqueous solutions in a wide concentration range from dense to extreme dilute solutions. We studied the vibrational dephasing and vibrational frequency modulation by calculating time correlation functions of vibrational relaxation by fits in the frequency domain. The concentration induced variations in bandwidths, band frequencies and characteristic dephasing times have been estimated and interpreted as effects due to solute-solvent interactions. The time-correlation functions of vibrational dephasing were obtained for the ring breathing mode of both "free" and hydrogen-bonded pyridine molecules and it was found that sufficiently deviate from the Kubo model. There is a general agreement in the whole concentration range with the modeling proposed by the Rothschild approach, which applies to complex liquids. The results have shown that the reorientation of pyridine aqueous solutions is very slow and hence in both scattering geometries only vibrational dephasing is probed. It is proposed that the spectral changes depend on the perturbations induced by the dynamics of the water molecules in the first hydration cell and water in bulk, while at extreme dilution conditions, the number of bulk water molecules increases and the interchange between molecules belonging to the first hydration cell may not be the predominant modulation mechanism. The evolution of several parameters, such as the characteristic times, the percentage of Gaussian character in the peak shape and the a parameter are indicative of drastic variations at extreme dilution revealing changes in the vibrational relaxation of the pyridine complexes in the aqueous environment. The higher dilution is correlated to diffusion of water molecules into the reference pyridine system in agreement with the jump diffusion model, while at extreme dilutions, almost all pyridine molecules are

  7. Enhancement of 4-electron O2 reduction by a Cu(ii)-pyridylamine complex via protonation of a pendant pyridine in the second coordination sphere in water.

    Science.gov (United States)

    Kotani, Hiroaki; Yagi, Tomomi; Ishizuka, Tomoya; Kojima, Takahiko

    2015-09-07

    We have synthesised a novel copper(ii) complex with a pyridine pendant as a proton relay port for electrocatalytic 4e(-) reduction of O2 in water. The enhancement of the electrocatalytic O2 reduction via protonation of the pyridine pendant is demonstrated in comparison with a copper(ii) complex without the pyridine pendant.

  8. Facile Diversity-Oriented Synthesis of Polycyclic Pyridines and Their Cytotoxicity Effects in Human Cancer Cell Lines.

    Science.gov (United States)

    Goswami, Limi; Gogoi, Shyamalee; Gogoi, Junali; Boruah, Rajani K; Boruah, Romesh C; Gogoi, Pranjal

    2016-05-09

    A three-component cascade method has been developed for the direct synthesis of polysubstituted pyridines. This strategy provides a very convenient route to pyridines using a variety of β-bromo-α,β-unsaturated aldehydes, 1,3-diketones, and ammonium acetate without any additional catalyst or metal salt under mild conditions. A variety of β-ketoesters and 4-hydroxycoumarin were also used instead of 1,3-diketones for the diverse synthesis of polycyclic pyridines. One of the synthesized pyridines has been unambiguously established by a single crystal XRD study. All of the synthesized pyridine derivatives were evaluated for their antiproliferative properties in vitro against the human cancer cell lines HeLa, Me180, and ZR751. Compounds 4{4,1} and 4{2,4} showed significant cytotoxicity in the human breast cancer cell line ZR751 and cervical cancer cell line Me180, respectively, and a few other compounds were found to have moderate activities.

  9. Solvatochromic study of highly fluorescent alkylated isocyanonaphthalenes, their π-stacking, hydrogen-bonding complexation, and quenching with pyridine.

    Science.gov (United States)

    Nagy, Miklós; Rácz, Dávid; Lázár, László; Purgel, Mihály; Ditrói, Tamás; Zsuga, Miklós; Kéki, Sándor

    2014-11-10

    Mono- and dialkylated derivatives of 1-amino-5-isocyanonaphthalene (ICAN) were studied as new members of a multifunctional, easy-to-prepare fluorophore family, which showed excellent solvatochromic properties. The monoallyl derivative and the starting ICAN exhibited strong fluorescence quenching in the presence of small amounts of pyridine. The formation of a hydrogen-bonded ground-state pyridine complex was detected; however, analysis of quantum chemical calculations suggested the presence of an additional π-stacked pyridine complex. The Stern-Volmer plot of the quenching process exhibited a downward curvature and after reaching a minimum the fluorescence intensity increased back to a significant level at high pyridine concentrations. Significant fluorescence was observed even in pure pyridine. A new mechanism and a simple mathematical equation were derived to explain the downward curvature and the remaining fluorescence by the formation of a fluorescent π-stacked complex.

  10. Tetraaquabis(pyridine-κNcobalt(II bis[4-amino-N-(6-chloropyridazin-3-ylbenzenesulfonamidate

    Directory of Open Access Journals (Sweden)

    Zhen-Feng Chen

    2009-12-01

    Full Text Available The structure of the title compound, [Co(C5H5N2(H2O4](C10H8ClN4O2S2, consists of a discrete tetraaquabis(pyridine-κNcobalt(II cation and two 4-amino-N-(6-chloropyridazin-3-ylbenzenesulfonamidate anions. In the cation, the CoII ion sits on an inversion centre and is octahedrally coordinated by two pyridine N atoms and four O atoms. A two-dimensional network parallel to (010 is formed via intermolecular O—H...O, O—H...N, N—H...N and N—H...O hydrogen bonds.

  11. 2-Methoxycarbonylpyridinium tetrachlorido(pyridine-2-carboxylato-κ2N,Ostannate(IV

    Directory of Open Access Journals (Sweden)

    Ezzatollah Najafi

    2011-02-01

    Full Text Available In the reaction of pyridine-2-carboxylic acid and stannic chloride in methanol, one equivalent of the carboxylic acid is protonated at the amino site and is also esterified, yielding the title salt, (C7H8NO2[SnCl4(C6H4NO2]. The SnIV atom in the anion is N,O-chelated by a pyridine-2-carboxylate in a cis-SnNOCl4 octahedral geometry. The cation is linked to the anion by an N—H...O hydrogen bond.

  12. Fine-tuning of atomic point charges: Classical simulations of pyridine in different environments

    Science.gov (United States)

    Macchiagodena, Marina; Mancini, Giordano; Pagliai, Marco; Del Frate, Gianluca; Barone, Vincenzo

    2017-06-01

    A correct description of electrostatic contributions in force fields for classical simulations is mandatory for an accurate modeling of molecular interactions in pure liquids or solutions. Here, we propose a new protocol for point charge fitting, aimed to take into the proper account different polarization effects due to the environment employing virtual sites and tuning the point charge within the polarizable continuum model framework. The protocol has been validated by means of molecular dynamics simulations on pure pyridine liquid and on pyridine aqueous solution, reproducing a series of experimental observables and providing the information for their correct interpretation at atomic level.

  13. Isomerisation of aldoses in pyridine in the presence of aluminium oxide.

    Science.gov (United States)

    Ekeberg, Dag; Morgenlie, Svein; Stenstrøm, Yngve

    2005-02-28

    Addition of aluminium oxide to boiling pyridine solutions of D-xylose, L-arabinose, D-mannose and D-glucose strongly increased the reaction rate of the aldose-ketose transformation. The maximum content of 2-ketose was reached after less than 2h for the aldopentoses and 3h for the aldohexoses. D-Threo-2-pentulose (xylulose) was prepared from D-xylose, and isolated as its O-isopropylidene derivative, the yield was nearly twice that compared to that usually obtained in the classical Lobry de Bruyn-Alberda van Ekenstein transformation in pyridine.

  14. 8-Hydroxy-2-methylquinolinium tetrachlorido(pyridine-2-carboxylato-κ2N,Ostannate(IV

    Directory of Open Access Journals (Sweden)

    Ezzatollah Najafi

    2011-02-01

    Full Text Available In the reaction of pyridine-2-carboxylic acid and stannic chloride in the presence of 2-methyl-8-hydroxyquinoline, the 2-methyl-8-hydroxyquinoline is protonated, yielding the title salt, (C10H10NO[SnCl4(C6H4NO2]. The SnIV atom in the anion is N,O-chelated by a pyridine-2-carboxylate in a cis-SnNOCl4 octahedral geometry. The cation is linked to the anion by an O—H...O hydrogen bond.

  15. MICROWAVE PROMOTED SUZUKI COUPLINGS OF 2,6-DIBROMO PYRIDINE WITH ARYL BORONIC ACIDS : SYNTHESIS OF MONO AND DIARYL PYRIDINES MICROWAVE PROMOTED Suzuki-Kupplungen von 2,6-DIBROMO PYRIDINE Mit Arylboronsäuren: Synthese von Mono-und Diaryl PYRIDINE

    Directory of Open Access Journals (Sweden)

    Hemasri Y, Mallikarjun,Jayaprakash Rao Y

    2013-01-01

    Full Text Available A simple and general method for the synthesis of symmetrical and unsymmetrical aryl pyridines developed under Microwave irradiation by adopting Suzuki-Miyaura cross couplings. A variety of boronic acids are coupled with 2, 6-dibromo pyridines (1a – h using Pd[dppf]Cl2 under conventional and Microwave irradiation. Microwave irradiation facilitated reaction course and afforded mono(2a – h and double coupled(3a – h products in moderate to high yields in just 15 mins

  16. Photodissociation of Isoxazole and Pyridine Studied Using Chirped Pulse Microwave Spectroscopy in Pulsed Uniform Supersonic Flows

    Science.gov (United States)

    Ariyasingha, Nuwandi M.; Joalland, Baptiste; Mebel, Alexander M.; Suits, Arthur

    2016-06-01

    Chirped - Pulse Fourier-transform microwave spectroscopy in uniform supersonic flows (Chirped- Pulse/Uniform Flow: CPUF) has been applied to study the photodissociation of two atmospherically relevant N containing heterocyclic compounds; pyridine and isoxazole. Products were detected using rotational spectroscopy. HC3N, HCN were observed for pyridine and CH3CN, HCO and HCN were observed for isoxazole and we report the first detection of HNC for both of the systems. Key points in potential energy surface were explored and compared with the experimental observations. Branching ratios were calculated for all the possible channels and will be presented.

  17. Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

    Directory of Open Access Journals (Sweden)

    Elena Borsini

    2011-10-01

    Full Text Available In a simple procedure, the intramolecular hydroarylation of N-propargyl-pyrrole-2-carboxamides was accomplished with the aid of gold(III catalysis. The reaction led to differently substituted pyrrolo[2,3-c]pyridine and pyrrolo[3,2-c]pyridine derivatives arising either from direct cyclization or from a formal rearrangement of the carboxamide group. Terminal alkynes are essential to achieve bicyclic pyrrolo-fused pyridinones by a 6-exo-dig process, while the presence of a phenyl group at the C–C triple bond promotes the 7-endo-dig cyclization giving pyrrolo-azepines.

  18. Synthesis, antimicrobial and cytotoxic activities of 5-benzylidene-2-[(pyridine-4-ylmethylenehydrazono]-thiazolidin-4-one and 2-[(pyridine-4-ylmethylene hydrazono]-thiazolidin-4-one derivatives

    Directory of Open Access Journals (Sweden)

    Danniel Delmondes Feitoza

    2012-01-01

    Full Text Available A new series of 5-benzylidene-2-[(pyridine-4-ylmethylenehydrazono]-thiazolidin-4-ones 4a-l have been synthesized. These compounds were designed by a molecular hybridization approach. 2-[(Pyridine-4-ylmethylenehydrazono]-thiazolidin-4-ones 3a-d were also obtained and used as intermediates to give the target compounds. The in vitro antimicrobial and cytotoxic activities were evaluated for both series. The intermediate 3b showed considerable antibiotic activity against B. subtilis and C. albicans. In the cytotoxic activity compounds 3b (IC50= 4.25 ± 0.36 µg/mL and 4l (IC50= 1.38 ± 0.04 µg/mL were effective for inhibition of human erythromyeloblastoid leukemia (K-562 and human lung carcinoma (NCI-H292 cell lines, respectively.

  19. {2,6-Bis[(pyridin-2-ylsulfanylmethyl]pyridine-κ2N,N′}(η3-prop-2-enylpalladium(II hexafluorophosphate

    Directory of Open Access Journals (Sweden)

    Giuseppe Bruno

    2014-04-01

    Full Text Available The title compound, [Pd(C3H5(C17H15N3S2]PF6, is built up by a [(η3-allylPd]2+ fragment coordinated by a 2,6-bis[(pyridin-2-ylsulfanylmethyl]pyridine ligand coordinated through the N atoms. One of the S atoms is at a close distance to the metal centeratom [3.2930 (8 Å]. The PdII atom is tetracoordinated in a strongly distorted square-planar environment mainly determined by the η3-allyl anion in which the central C atom is disordered over two equally occupied positions. The crystal packing is very compact and is characterized by a three-dimensional network of C—H...F interactions between the F atoms of each anion and several H atoms of the surrounding cationic complexes.

  20. Synthesis, antimicrobial and cytotoxic activities of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-one and 2-[(pyridine-4-ylmethylene) hydrazono]-thiazolidin-4-one derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Feitoza, Danniel Delmondes; Alves, Antonio Jose; Lima, Jose Gildo de, E-mail: jgildolima@gmail.com [Departamento de Ciencias Farmaceuticas, Universidade Federal de Pernambuco, Recife - PE (Brazil); Araujo, Janete Magali; Aguiar, Jaciana Santos; Rodrigues, Maria do Desterro; Silva, Teresinha Goncalves; Nascimento, Silene Carneiro do; Goes, Alexandre Jose da Silva [Departamento de Antibioticos, Universidade Federal de Pernambuco, Recife - PE (Brazil)

    2012-07-01

    A new series of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 4a-l have been synthesized. These compounds were designed by a molecular hybridization approach. 2-[(Pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 3a-d were also obtained and used as intermediates to give the target compounds. The in vitro antimicrobial and cytotoxic activities were evaluated for both series. The intermediate 3b showed considerable antibiotic activity against B. subtilis and C. albicans. In the cytotoxic activity compounds 3b (IC{sub 50} = 4.25 +- 0.36 {mu}g/mL) and 4l (IC{sub 50} = 1.38 +- 0.04 {mu}g/mL) were effective for inhibition of human erythromyeloblastoid leukemia (K-562) and human lung carcinoma (NCI-H292) cell lines, respectively. (author)

  1. Sorption of pure N2O to biochars and other organic and inorganic materials under anhydrous conditions

    Science.gov (United States)

    Cornelissen, Gerard; Rutherford, David W.; Arp, Hans Peter H.; Dorsch, Peter; Kelly, Charlene N.; Rostad, Colleen E.

    2013-01-01

    Suppression of nitrous oxide (N2O) emissions from soil is commonly observed after amendment with biochar. The mechanisms accounting for this suppression are not yet understood. One possible contributing mechanism is N2O sorption to biochar. The sorption of N2O and carbon dioxide (CO2) to four biochars was measured in an anhydrous system with pure N2O. The biochar data were compared to those for two activated carbons and other components potentially present in soils—uncharred pine wood and peat—and five inorganic metal oxides with variable surface areas. Langmuir maximum sorption capacities (Qmax) for N2O on the pine wood biochars (generated between 250 and 500 °C) and activated carbons were 17–73 cm3 g–1 at 20 °C (median 51 cm3 g–1), with Langmuir affinities (b) of 2–5 atm–1 (median 3.4 atm–1). Both Qmaxand b of the charred materials were substantially higher than those for peat, uncharred wood, and metal oxides [Qmax 1–34 cm3 g–1 (median 7 cm3 g–1); b 0.4–1.7 atm–1 (median 0.7 atm–1)]. This indicates that biochar can bind N2O more strongly than both mineral and organic soil materials. Qmax and b for CO2 were comparable to those for N2O. Modeled sorption coefficients obtained with an independent polyparameter—linear free-energy relationship matched measured data within a factor 2 for mineral surfaces but underestimated by a factor of 5–24 for biochar and carbonaceous surfaces. Isosteric enthalpies of sorption of N2O were mostly between −20 and −30 kJ mol–1, slightly more exothermic than enthalpies of condensation (−16.1 kJ mol–1). Qmax of N2O on biochar (50000–130000 μg g–1 biochar at 20 °C) exceeded the N2O emission suppressions observed in the literature (range 0.5–960 μg g–1 biochar; median 16 μg g–1) by several orders of magnitude. Thus, the hypothesis could not be falsified that sorption of N2O to biochar is a mechanism of N2O emission suppression.

  2. Contribution to the study of several chemical hazards in the Centre d'Etudes Nucleaires of Fontenay-aux-Roses; Contribution a l'etude de quelques nuisances chimiques au centre d'etudes nucleaires de Fontenay-aux-Roses

    Energy Technology Data Exchange (ETDEWEB)

    Megemont, C.; Grau, C. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-10-01

    From the checking of 2750 index cards of hazards, the study relates the distribution of the chemical hazards in the Centre d'Etudes Nucleaires of Fontenay-aux-Roses. Those concerning the greatest number of agents in the Centre are classified according to the categories corresponding to the different conditions of working. Thus, the most important are put forward. Then, the authors rapidly make a review of hazards which may have some special interest because they appear more specific of the nuclear energy or because they are the most frequently noted on the index cards of hazards. The case of the tributylphosphate is studied more precisely. (authors) [French] A partir de l'examen de 2750 fiches de nuisances, l'etude porte sur la repartition des nuisances chimiques au Centre d'Etudes Nucleaires de Fontenay-aux-Roses. Celles qui concernent le plus grand nombre d'agents du Centre sont classees selon les categories correspondant aux differentes conditions de travail. Les plus importantes d'entre elles sont ainsi mises en evidence. | Les auteurs passent ensuite en revue, rapidement, les nuisances qui peuvent presenter un interet particulier soit parce qu'elles semblent plus specifiques de l'Energie Nucleaire, soit parce qu'on les rencontre le plus frequemment sur les fiches de nuisances. Le cas du tributylphosphate est envisage de facon plus detaillee. (auteurs)

  3. Novel pyridine containing ligands as models for the copper centres in nitrite reductase

    CERN Document Server

    Arnold, P J

    2001-01-01

    This thesis is concerned with the synthesis of a series of novel pyridine containing ligands and their copper co-ordination chemistry. The aim was to design ligands which would produce copper complexes which model the active sites within certain copper-containing Nitrite Reductase enzymes. The first chapter reviews previous work in this area and details the promising nature of pyridine-containing ligands. The remainder of this thesis is concerned with the synthesis and characterisation of some novel pyridine-containing ligands and their copper chemistry. The synthetic routes developed during this work enabled tris(pyrid-2-yl)methylamine ligands to be produced and studied which were tripodal in form but which had a primary amine group at the cap which could be further elaborated. Additional substituents were also placed on the pyridine rings to investigate their impact on the chemistry of their copper complexes. These ligands showed a variety, counter ion dependent chemistry. The structures of number of the co...

  4. (Z-3-Amino-5-(pyridin-2-ylmethylidene-2-thioxo-1,3-thiazolidin-4-one

    Directory of Open Access Journals (Sweden)

    Petra Hirsova

    2015-11-01

    Full Text Available 3-Aminorhodanine reacts with aldehydes to form either 5-[(arylalkylidene]-substituted products or Schiff bases or derivatives substituted at both the 3-amino group and the 5-methylene group, depending on the reaction conditions. In this note, synthesis and characterization of 3-amino-5-(pyridin-2-ylmethylidene-2-thioxo-1,3-thiazolidin-4-one is reported.

  5. Preparation and Luminescence Thermochromism of Tetranuclear Copper(I)-Pyridine-Iodide Clusters

    Science.gov (United States)

    Parmeggiani, Fabio; Sacchetti, Alessandro

    2012-01-01

    A simple and straightforward synthesis of a tetranuclear copper(I)-pyridine-iodide cluster is described as a laboratory experiment for advanced inorganic chemistry undergraduate students. The product is used to demonstrate the fascinating and visually impressive phenomenon of luminescence thermochromism: exposed to long-wave UV light, the…

  6. 1,2-Bis (pyridin-2-ylmethyl)sulfanyl ethane and its dimorphic hydrochloride salt

    DEFF Research Database (Denmark)

    Lennartson, A.; McKenzie, C. J.

    2011-01-01

    and are held together by C-H center dot center dot center dot N and C-H center dot center dot center dot S interactions, resulting in the formation of a three-dimensional network structure. In addition, two polymorphs of the corresponding hydrochloride salt, 2-[(2-[(pyridin-1-ium-2-ylmethyl...

  7. Utility of Sulphones in Heterocyclic Synthesis: Synthesis of Some Pyridine, Chromene and Thiophene Derivatives

    Directory of Open Access Journals (Sweden)

    M. E. A. Zaki

    2000-05-01

    Full Text Available Phenylsulfonylacetonitrile (1 when reacted with α,β-unsaturated nitriles (2a,b and/or 2-hydroxynaphthaldehyde yields pyridine derivatives (3a,b and / or the iminochromene derivative (4 respectively. The behavior of (1 towards some a-halogenated compounds has been investigated.

  8. Preparation and Luminescence Thermochromism of Tetranuclear Copper(I)-Pyridine-Iodide Clusters

    Science.gov (United States)

    Parmeggiani, Fabio; Sacchetti, Alessandro

    2012-01-01

    A simple and straightforward synthesis of a tetranuclear copper(I)-pyridine-iodide cluster is described as a laboratory experiment for advanced inorganic chemistry undergraduate students. The product is used to demonstrate the fascinating and visually impressive phenomenon of luminescence thermochromism: exposed to long-wave UV light, the…

  9. (2E-3-(4-Methylphenyl-1-(pyridin-3-ylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Mauricio de Sousa Oliveiria

    2012-08-01

    Full Text Available The title compound, C15H13NO, has two crystallographically independent molecules in the asymmetric unit which differ principally in the periplanar angle formed by the benzene and pyridine rings [41.41 (3 and 17.92 (5°]. The molecules exhibit an E conformation between the keto group with respect to the olefin double bond.

  10. Chemical and electronic non-innocence of the bis(imine) pyridine ligand

    NARCIS (Netherlands)

    Knijnenburg, Q.

    2006-01-01

    Bis(imine) pyridine ligands combine two striking characteristics. On the one hand, they are extremely non-innocent in the sense that they interfere in the chemistry of their complexes, both chemically and electronically. On the other hand, their Fe and Co complexes form one of the known two late tra

  11. The synthesis of a pyridine-N-oxide isophthalamide rotaxane utilizing supplementary amide hydrogen bond interactions.

    Science.gov (United States)

    Evans, Nicholas H; Gell, Charles E; Peach, Michael J G

    2016-08-16

    The synthesis of a pyridine-N-oxide containing rotaxane, not requiring an additional ionic template, has been achieved in 32% yield. Successful rotaxane formation is dependent upon the structure of the isophthalamide macrocycle used, an observation which has been rationalised by a combination of NMR spectroscopy, X-ray crystallography and computational modelling.

  12. 1,2-Bis (pyridin-2-ylmethyl)sulfanyl ethane and its dimorphic hydrochloride salt

    DEFF Research Database (Denmark)

    Lennartson, A.; McKenzie, C. J.

    2011-01-01

    and are held together by C-H center dot center dot center dot N and C-H center dot center dot center dot S interactions, resulting in the formation of a three-dimensional network structure. In addition, two polymorphs of the corresponding hydrochloride salt, 2-[(2-[(pyridin-1-ium-2-ylmethyl...

  13. Synthesis and Antimicrobial Activity of Some New Chalcones of 2-Acetyl Pyridine

    Directory of Open Access Journals (Sweden)

    Y. Rajendra Prasad

    2008-01-01

    Full Text Available Six new chalcones were synthesised by condensing 2-acetyl pyridine with aldehyde derivatives in dilute ethanolic potassium hydroxide solution at room temperature according to Claisen-Schmidt condensation. All these compounds were characterised by means of their IR, 1H NMR spectroscopic data and microanalyses. The antimicrobial activity of these compounds was evaluated by the cup plate method.

  14. Synthesis and Antimicrobial Activity of Some New Chalcones of 2-Acetyl Pyridine

    OpenAIRE

    2008-01-01

    Six new chalcones were synthesised by condensing 2-acetyl pyridine with aldehyde derivatives in dilute ethanolic potassium hydroxide solution at room temperature according to Claisen-Schmidt condensation. All these compounds were characterised by means of their IR, 1H NMR spectroscopic data and microanalyses. The antimicrobial activity of these compounds was evaluated by the cup plate method.

  15. Bis{2-[(4-bromophenyliminomethyl]pyridine-κ2N,N′}copper(I tetraphenylborate

    Directory of Open Access Journals (Sweden)

    Maryam Hajikazemi

    2008-08-01

    Full Text Available In the crystal structure of the title compound, [Cu(C12H9BrN22](C24H20B, the copper(I cation is coordinated by four N atoms of two crystallographically independent 2-[(4-bromophenyliminomethyl]pyridine ligands within a distorted tetrahedron.

  16. Re-mediated C-C coupling of pyridines and imidazoles.

    Science.gov (United States)

    Espinal Viguri, Maialen; Huertos, Miguel A; Pérez, Julio; Riera, Lucía; Ara, Irene

    2012-12-19

    Rhenium tricarbonyl complexes with three N-heterocyclic ligands (N-alkylimidazoles or pyridines) undergo deprotonation with KN(SiMe(3))(2) and then oxidation with AgOTf to afford complexes with pyridylimidazole or bipyridine bidentate ligands resulting from deprotonation, C-C coupling and rearomatization.

  17. Determination of pyridine in soil and water samples of a polluted area

    NARCIS (Netherlands)

    Peters, R.J.B.; Renesse van Duivenbode, J.A.D. van

    1994-01-01

    A method for the analyses of pyridine in environmental samples is described. For soil samples a distillation procedure followed by an extraction, an acidic extraction or a Soxhlet extraction can be used. For water samples a distillation procedure followed by extraction can be employed. Deuterated py

  18. SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF NEW SULFONAMIDE ISOXAZOLO[5,4-b]PYRIDINE DERIVATIVES.

    Science.gov (United States)

    Poręba, Krystyna; Pawlik, Krzysztof; Rembacz, Krzysztof P; Kurowska, Ewa; Matuszyk, Janusz; Długosz, Anna

    2015-01-01

    A series of novel sulfonamide isoxazolo[5,4-b]pyridines were synthesized. The substrates for their synthesis were 3-aminoisoxazolo[5,4-b]pyridine and selected aryl sulfonic chlorides, chlorosulfonic acid and selected amines. Reactions were carried out using the classical and microwave methods. Selected compounds were tested towards antibacterial and antiproliferative activity. The structure of the obtained new derivatives was determined by elemental analysis and acquired IR and 1H NMR spectra. Among the tested compounds: N- isoxazolo[5,4-b]pyridine-3-yl-benzenesulfonamide (2) and N-isoxazolo[5,4-b]pyridine-3-yl-4-methylbenzene-sulfonamide (5) showed antimicrobial activity towards Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922) at doses: 125, 250 and 500 µg. Both compounds showed a 50% inhibition of proliferation of breast carcinoma cell line MCF7 at concentrations of 152.56 µg/mL and 160 161.08 µg/mL, respectively.

  19. Monasnicotinates A–D, Four New Pyridine Alkaloids from the Fungal Strain Monascus pilosus BCRC 38093

    Directory of Open Access Journals (Sweden)

    Gwo-Fang Yuan

    2011-06-01

    Full Text Available Four new pyridine derivatives, monasnicotinates A–D (1–4 were isolated from the red yeast rice of Monascus pilosus BCRC 38093. Their structures were elucidated on the basis of physicochemical evidence, in-depth NMR spectroscopic analysis, and high-resolution mass spectrometry. Their inhibitory effects on NO production was also evaluated.

  20. Inorganic-organic hybrid membranes with anhydrous proton conduction prepared from 3-aminopropyltriethoxysilane and sulfuric acid by the sol-gel method.

    Science.gov (United States)

    Tezuka, Teruaki; Tadanaga, Kiyoharu; Hayashi, Akitoshi; Tatsumisago, Masahiro

    2006-12-27

    Inorganic-organic hybrid membranes with anhydrous proton conduction were prepared from 3-aminopropyltriethoxysilane and H2SO4 by the sol-gel method. The membrane has a unique structure: a hexagonal phase formed by the stacking of rodlike polysiloxanes with ion complexes of ammonium groups and HSO4- extruded outside. The membranes showed high conductivity of 2 x 10-3 S cm-1 at 200 degrees C under dry atmosphere. In the membrane, protons probably migrate through the outside of the rodlike polysiloxanes along hydrogen-bond chains formed among HSO4- anions.

  1. Adulteration determination of the anhydrous ethanol fuels samples with methanol; Determinacao de adulteracao por metanol em amostras de alcool etilico anidro combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Eduardo; Mota, Claudio J.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica]. E-mail: eduardoc@dh.com.br; cmota@iq.ufrj.br

    2003-07-01

    A fast test made to evidence an adulteration of anhydrous ethanol with methanol consist in mixing the alcohol with gasoline. A pink coloration indicates the adulteration by methanol. Samples of gasoline A, ethanol and high purity methanol were mixed at different proportions, but no color change was observed. On the other hand, samples of gasoline A, ethanol and formaldehyde 40% showed the characteristic pink coloration, for methanol adulteration. This result indicates that the test is sensible to the presence of formaldehyde, probably presence as impurity or formed by oxidation of the methanol. A lower detection limit of 4.8% of formaldehyde in the alcohol was determined. (author)

  2. Synthesis and Suzuki Cross-Coupling Reactions of 2,6-Bis(trifluoromethyl)pyridine-4-boronic Acid Pinacol Ester

    KAUST Repository

    Batool, Farhat

    2016-11-18

    Iridium-catalyzed aromatic borylation provides quick one-step access to 2,6-bis(trifluoromethyl)pyridine-4-boronic acid pinacol ester. Suzuki couplings of this highly electron-deficient pyridine-4-boronic ester with various (hetero)aryl bromides was successfully carried out and the coupled products were obtained in 46–95% isolated yields. Double and triple Suzuki couplings, with dibromo- and tribromoarenes, respectively, were also achieved. Thus demonstrating that this pyridine-4-boronic ester can be a useful source for the installation of one of the strongest electron-withdrawing aromatic group in organic compounds. Copyright © 2016, Georg Thieme Verlag. All rights reserved.

  3. Influence of surfactant concentration on counter-ion induced solubility of poly(pyridine-2,5-diyl)

    Institute of Scientific and Technical Information of China (English)

    IMIT Mokhtar; YAMAMOTO Takakazu; IMIN Patigul

    2005-01-01

    Protonating the pyridine rings of poly(pyridine-2,5-diyl) with dodecybenzenesulfonic acid and camphorsulphonic acid produces polymer materials which can be dissolved in chloroform (in contrast to the unprotonated polymer, which can only be dissolved in strong acids such as formic acid) and allows mixing the protonated polymers with other chloroform soluble conjugated polymers for use in electronic devices. The protonating behavior of poly(pyridine-2,5-diyl) with two kinds of surfactants is different in some levels. Dodecybenzenesulfonic acid has higher protonating ability than camphorsulphonic acid.

  4. Ringwoodite growth rates from olivine with ~75 ppmw H2O: Metastable olivine must be nearly anhydrous to exist in the mantle transition zone

    Energy Technology Data Exchange (ETDEWEB)

    Du Frane, Wyatt L. [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Atmospheric, Earth and Energy Division; Sharp, Thomas G. [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration; Mosenfelder, Jed L. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Geological and Planetary Sciences; Leinenweber, Kurt [Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration

    2013-04-15

    It has been previously demonstrated that as little as 300 ppmw H2O increases wadsleyite and ringwoodite growth rates to magnitudes that are inconsistent with the metastable olivine hypothesis. To further test this hypothesis, we present new ringwoodite growth rate measurements from olivine with ~75 ppmw H2O at 18 GPa and 700, 900, and 1100 °C. These growth rates are nearly identical to those from olivine with ~300 ppmw H2O, and significantly higher than those from nominally anhydrous olivine. We infer that transformation of olivine with 75-300 ppmw H2O is primarily enhanced by hydrolytic weakening of reaction rims, which reduces the elastic strain-energy barrier to growth. We present a new method for fitting nonlinear nominally anhydrous data, to demonstrate that reduction of growth rates by elastic strain energy is an additional requirement for metastable olivine. In conclusion, based on previous thermokinetic modeling, these enhanced growth rates are inconsistent with the persistence of metastable olivine wedges into the mantle transition zone. Metastable persistence of olivine into the mantle transition-zone would therefore require < 75 ppmw H2O.

  5. Scientific Opinion on the safety and efficacy of betaine anhydrous as a feed additive for all animal species based on a dossier submitted by Danisco Animal Nutrition

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-05-01

    Full Text Available Glycine betaine (betaine acts as a methyl group donor in transmethylation reactions in organisms. Betaine occurs in numerous vertebrate tissues as an osmolyte, ensuring osmoprotection. Betaine is safe for piglets at the maximum supplementation rate of 2 000 mg/kg complete feed with a margin of safety below 5. This conclusion is extended to all pigs and extrapolated to all animal species and categories. The use of betaine as a feed additive up to a supplementation rate of 2 000 mg/kg complete feed is unlikely to pose concerns for consumer safety. Users’ inhalation exposure to betaine is expected to be minimal. Betaine anhydrous should be considered irritant to skin, eyes and mucous membranes and a skin sensitiser. It is likely to cause skin sensitisation. The supplementation of feed with betaine anhydrous does not pose a risk to the environment. Betaine has the potential to become efficacious in all animal species and categories when administered via feed or water for drinking. The FEEDAP Panel made some recommendations on (i introduction of a maximum content for supplemental betaine in complete feed and water for drinking; (ii avoidance of simultaneous use of betaine in feed and water for drinking; and (iii avoidance of simultaneous inclusion of betaine and choline chloride in premixtures.

  6. Synthesis and Spectral Studies of Copper (II and Manganese (II Complexes Using 2-Hydroxybenzyl-(pyridine-2-carboIminohydrazone and 2-Furyl(pyridine-2-carboIminohydrazone: Evaluation of Their Magnetic, and Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Jagvir Singh

    2013-01-01

    Full Text Available Three new coordination complexes [Cu(HPBH2]Cl2 (1, [Cu(FPFH2]Cl2 (2, and [Mn(HPBH2] Cl2 (3 (where HPBH=2-Hydroxybenzyl(pyridine-2-carboiminohydrazone, and FPFH=2-furyl(pyridine-2-carboiminohydrazone have been synthesized using two different tridentate hydrazones ligand. The ligands were prepared by condensation of Pyridine-2-acetylchloride, 2-Hydroxybenzaldehyde and Furan-2-carbaldehyde with hydrazine, respectively, in spite of varying the carbonyl functionality attached to the pyridine moiety present in the hydrazones ligand. In both the Schiff bases, we obtained three mononuclear complexes 1, 2, and 3 which were clearly characterized from physicochemical studies. Spectroscopic investigations like 1H and 13C NMR, mass spectrometric, FTIR, and UV/Vis have been carried out for new compounds. For complexes 2 cyclic voltammetry, magnetic and EPR properties have also been recorded. Antimicrobial studies have also been performed for these compounds with different antimicrobial species.

  7. Synthesis of meta-substituted [(18)F]3-fluoro-4-aminopyridine via direct radiofluorination of pyridine N-oxides.

    Science.gov (United States)

    Brugarolas, P; Freifelder, R; Cheng, S-H; DeJesus, O

    2016-06-04

    Due to their electron-rich aromatic structure, nucleophilic (radio)fluorination of pyridines is challenging, especially at the meta position. In this paper, we describe the first example of direct fluorination of a pyridine N-oxide to produce a meta fluorinated pyridine. Specifically, fluorination of 3-bromo-4-nitropyridine N-oxide produced in several minutes 3-fluoro-4-nitropyridine N-oxide in moderate yield at room temperature. This intermediate compound was later converted to 3-fluoro-4-aminopyridine easily by catalytic hydrogenation. Furthermore, this approach was successfully applied for labeling with fluorine-18. The use of pyridine N-oxides for the preparation of fluoropyridines is unprecedented in the chemical literature and has the potential to offer a new way for the synthesis of these important structures in pharmaceuticals and radiopharmaceuticals.

  8. Solubilization of silica: Synthesis, characterization and study of penta-coordinated pyridine N-oxide silicon complexes

    Indian Academy of Sciences (India)

    Subramania Ranganathan; Ch Chandrashekhar Rao; Suvarchala Devi Vudayagiri; Y B R D Rajesh; B Jagadeesh

    2004-03-01

    In an effort to design agents that could solubilize silica in water, under ambient conditions and pH, as takes place in nature, novel zwitterionic, penta-oxo-coordinated silicon compounds with siliconate cores have been prepared from 4-substituted pyridine N-oxides (H, OMe, morpholino, NO2) as donor ligands, their structures established by 1H, 13C and MS, and the coordination number of silicon, by 29Si NMR. The formation of complexes from pyridine N-oxides is noteworthy since they arise from interaction with a weakly nucleophilic oxygen centre. The ability of the pyridine N-oxides to enhance the solubilization of silica in water has been experimentally demonstrated. Possible rationalization of this observation on the basis of O→Si coordination via the oxygen atom of pyridine N-oxide is suggested.

  9. Influence of Boron Substitution on Conductance of Pyridine- and Pentane-Based Molecular Single Electron Transistors: First-Principles Analysis

    Science.gov (United States)

    Srivastava, Anurag; Santhibhushan, B.; Sharma, Vikash; Kaur, Kamalpreet; Shahzad Khan, Md.; Marathe, Madura; De Sarkar, Abir; Shahid Khan, Mohd.

    2016-04-01

    We have investigated the modeling of boron-substituted molecular single-electron transistor (SET), under the influence of a weak coupling regime of Coulomb blockade between source and drain metal electrodes. The SET consists of a single organic molecule (pyridine/pentane/1,2-azaborine/butylborane) placed over the dielectric, with boron (B) as a substituent. The impact of B-substitution on pyridine and pentane molecules in isolated, as well as SET, environments has been analyzed by using density functional theory-based ab initio packages Atomistix toolkit-Virtual NanoLab and Gaussian03. The performance of proposed SETs was analyzed through charging energies, total energy as a function of gate potential and charge stability diagrams. The analysis confirms that the B-substituted pentane (butylborane) and the boron-substituted pyridine (1,2-azaborine) show remarkably improved conductance in SET environment in comparison to simple pyridine and pentane molecules.

  10. An unexpected reaction of cyanothioacetamide: Novel preparation of pyrazolo[3,4-b]-pyridine derivatives under MWI

    Institute of Scientific and Technical Information of China (English)

    Xue Sen Fan; Xia Wang; Xiao Yan Li

    2008-01-01

    An unexpected multi-component reaction of cyanothioacetamide with aldehyde and aminopyrazole under MWI was reported. Through this reaction, a series of pyrazolo[3,4-b]-pyridine derivatives was prepared in high yields via simple operational procedure.

  11. The catalytic performance of Ru–NHC alkylidene complexes: PCy3 versus pyridine as the dissociating ligand

    Directory of Open Access Journals (Sweden)

    Stefan Krehl

    2010-12-01

    Full Text Available The catalytic performance of NHC-ligated Ru-indenylidene or benzylidene complexes bearing a tricyclohexylphosphine or a pyridine ligand in ring closing metathesis (RCM, cross metathesis, and ring closing enyne metathesis (RCEYM reactions is compared. While the PCy3 complexes perform significantly better in RCM and RCEYM reactions than the pyridine complex, all catalysts show similar activity in cross metathesis reactions.

  12. Design, synthesis and characterization of 1-pyridin-4-yl-3,5-disubstituted indazoles and their AKT inhibition activity

    Indian Academy of Sciences (India)

    Surendrareddy Gogireddy; Arunasree M Kalle; P K Dubey; Arava Veera Reddy

    2014-07-01

    A new series of 1-pyridin-4-yl-3,5-disubstituted indazoles and their derivatives were synthesized by the reaction of 5-Bromo-1-(2-cyano-pyridin-4-yl)-1-indazole-3-carboxylic acid diethylamide with aryl boronic acids by Suzuki coupling reaction in the presence of Pd(OAc)2 and CsF. All the new compounds have been characterized by spectral data. The title compounds were subsequently evaluated for their Akt kinase activity.

  13. Microwave-prompted rapid and efficient synthesis of 3-alkyl substituted imidazo[1,5-a] pyridines

    Institute of Scientific and Technical Information of China (English)

    Lai Bao Wang; Jia Pan; Can Ling Tang; Xiu Ren Bu; Jie Wang

    2007-01-01

    Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2′-pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and acetic acid. Compared to the traditional heating condition, the reaction time under microwave irradiation was shorter and 3-alkyl imidazo[1,5-a]pyridines were given in higher yield.

  14. Synthesis, antimicrobial and antimycobacterial evaluation of [2-(substituted phenyl)-imidazol-1-yl]-pyridin-3-yl-methanones.

    Science.gov (United States)

    Narasimhan, Balasubramanian; Sharma, Deepika; Kumar, Pradeep; Yogeeswari, Perumal; Sriram, Dharmarajan

    2011-10-01

    A series of [2-(substituted phenyl)-imidazol-1-yl]-pyridin-3-yl-methanones (1-11) were synthesized and screened for their antimicrobial and antimycobacterial activities. Further, a series of [2-(substituted phenyl)-benzimidazol-1-yl]-pyridin-3-yl-methanones (12-20) reported in our earlier study was also screened for their antimycobacterial activity. The antimycobacterial activity results indicated that [2-(4-Nitro-phenyl)-imidazol-1-yl]-pyridin-3-yl-methanone (8, minimum inhibitory concentration [MIC] = 3.13 µg) was equipotent as standard drug ciprofloxacin and [2-(4-Nitro-phenyl)-benzimidazol-1-yl]-pyridin-3-yl-methanone (16, MIC = 1.56 µg) was equipotent as standard drug ethambutol. The results of antimicrobial screening demonstrated that 2-[1-(Pyridine-3-carbonyl)-1H-imidazol-2-yl]-benzoic acid (compound 11, MIC = 0.002 µg) was two times more effective than standard drug ciprofloxacin (MIC = 0.004 µg) against tested bacterial strains and [2-(2,5-Dimethyl-phenyl)-imidazol-1-yl]-pyridin-3-yl-methanone (compound 3, MIC = 0.005 µg) was equipotent to the reference compound, fluconazole against tested fungal strains.

  15. 4-(Naphthalene-2-carboxamidopyridin-1-ium thiocyanate–N-(pyridin-4-ylnaphthalene-2-carboxamide (1/1

    Directory of Open Access Journals (Sweden)

    Sohail Saeed

    2012-10-01

    Full Text Available The asymmetric unit of the title compound, C16H13N2O+·NCS−·C16H12N2O, contains two N-(pyridin-4-ylnaphthalene-2-carboxamide molecules, both are partially protonated in the pyridine moiety, i.e. the H atom attached to the pyridine N atom is partially occupied with an occupancy factor of 0.61 (3 and 0.39 (3, respectively. In the crystal, protonated and neutral N-(pyridin-4-ylnaphthalene-2-carboxamide molecules are linked by N—H...N hydrogen bonding; the thiocyanate counter-ion links with both protonated and neutral N-(pyridin-4-ylnaphthalene-2-carboxamide molecules via N—H...S and N—H...N hydrogen bonding. The dihedral angles between the pyridine ring and naphthalene ring systems are 11.33 (6 and 9.51 (6°, respectively. π–π stacking is observed in the crystal structure, the shortest centroid–centroid distance being 3.5929 (8 Å. The crystal structure was determined from a nonmerohedral twin {ratio of the twin components = 0.357 (1:0.643 (1 and twin law [-100 0-10 -101]}.

  16. Novel semiconducting boron carbide/pyridine polymers for neutron detection at zero bias

    Energy Technology Data Exchange (ETDEWEB)

    Echeverria, Elena; Enders, A.; Dowben, P.A. [University of Nebraska-Lincoln, Department of Physics and Astronomy, Lincoln, NE (United States); James, Robinson; Chiluwal, Umesh; Gapfizi, Richard; Tae, Jae-Do; Driver, M. Sky; Kelber, Jeffry A. [University of North Texas, Department of Chemistry, Denton, TX (United States); Pasquale, Frank L. [University of North Texas, Department of Chemistry, Denton, TX (United States); Lam Research Corporation, PECVD Business Unit, Tualatin, OR (United States); Colon Santana, Juan A. [Center for Energy Sciences Research, Lincoln, NE (United States)

    2014-09-19

    Thin films containing aromatic pyridine moieties bonded to boron, in the partially dehydrogenated boron-rich icosahedra (B{sub 10}C{sub 2}H{sub X}), prove to be an effective material for neutron detection applications when deposited on n-doped (100) silicon substrates. The characteristic I-V curves for the heterojunction diodes exhibit strong rectification and largely unperturbed normalized reverse bias leakage currents with increasing pyridine content. The neutron capture generated pulses from these heterojunction diodes were obtained at zero bias voltage although without the signatures of complete electron-hole collection. These results suggest that modifications to boron carbide may result in better neutron voltaic materials. (orig.)

  17. Synthesis of Novel 1-(4-Substituted pyridine-3-sulfonyl-3-phenylureas with Potential Anticancer Activity

    Directory of Open Access Journals (Sweden)

    Krzysztof Szafrański

    2015-07-01

    Full Text Available A series of novel 4-substituted-N-(phenylcarbamoyl-3-pyridinesulfonamides 11–27 have been synthesized by the reaction of 4-substituted pyridine-3-sulfonamides 2–10 with the appropriate aryl isocyanates in presence of potassium carbonate. The in vitro anticancer activity of compounds 11, 12, 14–21 and 24–26 was evaluated at the U.S. National Cancer Institute and in light of the results, some structure-activity relationships were discussed. The most prominent compound, N-[(4-chlorophenylcarbamoyl]-4-[4-(3,4-dichlorophenylpiperazin-1-yl]pyridine-3-sulfonamide (21 has exhibited a good activity profile and selectivity toward the subpanels of leukemia, colon cancer and melanoma, with average GI50 values ranging from 13.6 to 14.9 µM.

  18. Stabilizing G-quadruplex DNA by methylazacalix[n]pyridine through shape-complementary interaction.

    Science.gov (United States)

    Guan, Ai-Jiao; Shen, Meng-Jie; Zhang, En-Xuan; Li, Qian; Wang, Li-Xia; Xu, Li-Jin; Xiang, Jun-Feng; Tang, Ya-Lin

    2016-01-15

    It is found that G-quadruplexes have important functions in biological systems, such as gene expression. Molecules which can stabilize the G-quadruplex structure may have potential application in regulating the expression of gene. A series of methylazacalix[n]pyridine (n=4, 6, 7, 8, 9) has been tested to stabilize the intermolecular human telomeric G-quadruplex (T12 and H12), intramolecular TBA, c-kit and bcl-2 G-quadruplex by CD denaturation experiments. The results showed that only methylazacalix[6]pyridine (MACP6) can stabilize the intermolecular G-quadruplex formed from the 12bp human telomere. Further studies evidenced that the shape-complementary binding mode was what contributed to the interaction between MACP6 and T12 G-quadruplex.

  19. SYNTHESIS AND BIOLOGIC PROPERTIES OF SOME 1-(ALCHYLPHENYL-3-(4-(3-(PYRIDIN-2-ILACRYLOYLPHENYLTHIOUREA

    Directory of Open Access Journals (Sweden)

    A. Popusoi

    2013-06-01

    Full Text Available This paper describe the synthesis of some 1-(alchylaril-3-(4-(3-pyridin-2-il acryloylphenylthiourea obtained by condensation of 2-pyridincarboxaldehide with some derivatives of 4-acetylphenilthioureas in basic medium or by addition of aliphatic and aromatic amines to the correspondingisothiocyanatopropenones. 12 new compounds were obtained and their biological properties were analysed. The substituted thioureas by pyridine radicals, morpholine and phenol show a maximum bacteriostatic activity for Gram positive microorganisms like: Staphylococcus Aureus and Enterococcus Faecalis at the minimum inhibitory concentration 9.37-37.5 μM. Antifungal activity for Candida Albicans, Aspergillus Niger, AspergillusFumigatus, Penicillium is weak, in minimum inhibitory concentration 600->600 μM. The leukemia activity like inhibitor (HL-60, is 84-96.9% at the concentration 10-5mol/l and 15- 20% and at the concentrations 10-6, 10-7mol/l.

  20. Ethyl 2-(pyridine-4-carboxamido-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Asma Mukhtar

    2012-07-01

    Full Text Available In the title compound, C17H18N2O3S, the dihedral angles between the thiophene ring and the ethyl ester group and the pyridine-4-carboxamide unit are 7.1 (2 and 9.47 (11°, respectively. An intramolecular N—H...O hydrogen bond generates an S(6 ring. In the crystal, inversion dimers linked by pairs of C—H...O hydrogen bonds between the tetrahydro-1-benzothiophene and the pyridine-4-carboxamide residues generate R22(16 loops. There exists positional disorder in three methelene groups of the cyclohexane ring and the terminal C atom of the ethyl ester side chain in a 0.691 (14:0.309 (14 occupancy ratio.

  1. NHC Versus Pyridine: How “Teeth” Change the Redox Behavior of Iron(II) Complexes

    KAUST Repository

    Weiss, Daniel T.

    2015-10-06

    A series of octahedral iron(II) complexes with tetradentate NHC/pyridine hybrid ligands containing up to three pyridyl units was designed to study the influence of NHC and pyridine donors on the electronic structure of the metal center. Structural analysis of the iron complexes by NMR spectroscopy and single-crystal X-ray diffraction reveals different coordination modes of the ligand depending on the linkage of the different donor moieties. The oxidation potentials of all complexes correlate linearly with the number of NHC moieties coordinated to iron, as shown by cyclic voltammetry. The influence, although minor, of structural properties on the oxidation potential and (in one case) the influence of the oxidation state of the coordination geometry of the hybrid ligand are also demonstrated.

  2. Bis{2,6-bis[(2-hydroxy-5-methylphenyliminomethyl]pyridine} monohydrate

    Directory of Open Access Journals (Sweden)

    Muhammet Kose

    2011-12-01

    Full Text Available The title compound, 2C21H19N3O2·H2O, was synthesized by a Schiff base condensation of 2,6-diformylpyridine with 2-amino-4-methylphenol in ethanol. In the crystal, two molecules of 2,6-bis[(2-hydroxy-5-methylphenyliminomethyl]pyridine dimerize via hydrogen bonding to a water molecule, which lies on a twofold axis. There are also intramolecular phenol–imine hydrogen bonds. The dimers are further linked via π–π (phenyl–pyridine [centroid–centroid distance = 3.707 (2 Å] and π–π edge-to-edge [3.392 (2 Å] interactions. The dihedral angles between the central ring and the two pendant rings are 11.46 (8 and 2.06 (8° while the pendant rings make a dihedral angle of 10.14 (8°.

  3. Spectral studies of copper(II) complexes of 6-(3-thienyl) pyridine-2-thiosemicarbazone

    Energy Technology Data Exchange (ETDEWEB)

    Mahjoub, Omima Abdalla; Farina, Yang [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2014-09-03

    Two novel copper(II) complexes [Cu(HL)Cl]Cl.H{sub 2}O (1) and [Cu(L)NO{sub 3}]Ðœ‡H{sub 2}O (2) of the three NNS donor thiosemicarbazone ligand 6-(3-thienyl) pyridine-2-thiosemicarbazone have been synthesized. The ligand and its copper(II) complexes were characterized by elemental analysis (C, H, N, and S), FT-IR, UV-visible, magnetic susceptibility and molar conductance. The thiosemicarbazone is present either as the thione form in complex 1 or as thiol form in complex 2 and is coordinated to copper(II) atom via the pyridine nitrogen atom, the azomethine nitrogen atom and the sulfur atom. The physicochemical and spectral data suggest square planar geometry for copper(II) atoms.

  4. Aldose-ketose interconversion in pyridine in the presence of aluminium oxide.

    Science.gov (United States)

    Ekeberg, Dag; Morgenlie, Svein; Stenstrøm, Yngve

    2007-10-15

    The reaction rate of the Lobry de Bruyn-Alberda van Ekenstein transformation of aldoses to ketoses in boiling pyridine was strongly increased by the addition of aluminium oxide. In addition to aldose-ketose transformation, 2-epimers of the starting aldoses and 3-epimers of the primarily produced ketoses were formed to some extent, as reported also when these reactions are carried out without aluminium oxide. The relative amounts of the primary ketose and the starting aldose in the reaction mixtures may be explained on the basis of their stability, predicted from reported free energy calculations. Isomerisation of ketoses to aldoses was much slower than the reverse reaction. The relative free energies are also in these cases important, the very stable xylo-2-hexulose gave only 7% and 6% of the aldoses gulose and idose, respectively, after boiling for 7h in pyridine in the presence of aluminium oxide.

  5. Electron energy-loss spectroscopy of excited states of the pyridine molecules

    Science.gov (United States)

    Linert, Ireneusz; Zubek, Mariusz

    2016-04-01

    Electron energy-loss spectra of the pyridine, C5H5N, molecules in the gas phase have been measured to investigate electronic excitation in the energy range 3.5-10 eV. The applied wide range of residual electron energy and the scattering angle range from 10° to 180° enabled to differentiate between optically-allowed and -forbidden transitions. These measurements have allowed vertical excitation energies of the triplet excited states of pyridine to be determined and tentative assignments of these states to be proposed. Some of these states have not been identified in the previous works. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  6. Structural analysis of pyridine-imino boronic esters involving secondary interactions on solid state

    Science.gov (United States)

    Sánchez-Portillo, Paola; Arenaza-Corona, Antonino; Hernández-Ahuactzi, Irán F.; Barba, Victor

    2017-04-01

    Twelve boronic esters (1a-1l) synthesized from 4-halo- substituted arylboronic acids (halo = F, Cl, Br, I and CF3) with 2-amino-2- alkyl (H, Me) -1,3-propanediol in presence of (3- or 4)-pyridine carboxaldehyde are described. A solvent mixture toluene/methanol 1:4 ratio was used. All compounds include both donor/acceptor functional groups, which are the necessary elements to self-assembly of the molecular species. Several secondary interactions as I⋯N, Br⋯Br, Br⋯B, F⋯B, Csbnd H⋯N, Csbnd H⋯O, Br⋯π and Csbnd H⋯π support the 1D and 2D polymeric frameworks in solid state. The coordination of the nitrogen atom from the pyridine moiety with the boron atom was not observed in either solution or solid state.

  7. Discovery of pyridine-based agrochemicals by using Intermediate Derivatization Methods.

    Science.gov (United States)

    Guan, Ai-Ying; Liu, Chang-Ling; Sun, Xu-Feng; Xie, Yong; Wang, Ming-An

    2016-02-01

    Pyridine-based compounds have been playing a crucial role as agrochemicals or pesticides including fungicides, insecticides/acaricides and herbicides, etc. Since most of the agrochemicals listed in the Pesticide Manual were discovered through screening programs that relied on trial-and-error testing and new agrochemical discovery is not benefiting as much from the in silico new chemical compound identification/discovery techniques used in pharmaceutical research, it has become more important to find new methods to enhance the efficiency of discovering novel lead compounds in the agrochemical field to shorten the time of research phases in order to meet changing market requirements. In this review, we selected 18 representative known agrochemicals containing a pyridine moiety and extrapolate their discovery from the perspective of Intermediate Derivatization Methods in the hope that this approach will have greater appeal to researchers engaged in the discovery of agrochemicals and/or pharmaceuticals.

  8. HEAT-RESISTANT PYRIDINE-BASED POLY(ETHER-ESTER)S: SYNTHESIS,CHARACTERIZATION AND PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    Shahram Mehdipour-Ataei; Ali Mahmoodi

    2013-01-01

    A pyridine-based diacid was synthesized via nucleophilic substitution reaction of 4-hydroxy benzoic acid with 2,6-dichloropyridine in the presence of potassium carbonate.The diacid was characterized using FT-IR and 1H-NMR spectroscopic methods and also with elemental analysis.Polycondensation reaction of the diacid with different diols including 1,4-dihydroxy benzene,1,5-dihydroxy naphthalene,bis-phenol A and bis-phenol-P resulted in preparation of pyridine-based poly(ether-ester)s.The polymers were characterized and their physical and thermal properties including inherent viscosity,molecular weight,solubility,thermal stability,thermal behavior and crystallinity were studied.They revealed high heat-resistance and improved solubility in polar solvents.Structure-property relations for the prepared polyester were also studied.

  9. Novel hydrazone derivatives containing pyridine amide moiety: Design, synthesis, and insecticidal activity.

    Science.gov (United States)

    Yang, Zai-Bo; Hu, De-Yu; Zeng, Song; Song, Bao-An

    2016-02-15

    A series of novel hydrazone derivatives containing pyridine amide moiety were designed, synthesized, and evaluated for their insecticidal activity. Bioassays indicated that some of the target compounds exhibited good insecticidal activities against Nilaparvata lugens (N. lugens), Plutella xylostella (P. xylostella), Mythimna separata (M. separata), Helicoverpa armigera (H. armigera), Pyrausta nubilalis (P. nubilalis), and Culex pipiens pallens (C. pipiens pallens). In particular, compound 5j revealed excellent insecticidal activity against C. pipiens pallens, with the 50% lethal concentration (LC50) and the 95% lethal concentration (LC95) values of 2.44 and 5.76 mg/L, respectively, which were similar to those of chlorpyrifos (3.26 and 6.98 mg/L, respectively), tebufenozide (1.22 and 2.49 mg/L, respectively), and RH-5849 (2.61 and 6.37 mg/L, respectively). These results indicated that hydrazone derivatives containing pyridine amide moiety could be developed as novel and promising insecticides.

  10. Compressibility of hydrated and anhydrous sodium silicate-based liquids and glasses, as analogues for natural silicate melts, by Brillouin scattering spectroscopy

    Science.gov (United States)

    Tkachev, Sergey Nikolayevich

    A mathematical formalism was tested on compressibility studies of water, before applying it to the high pressure-temperature compressibility studies of hydrated and anhydrous sodium silicate-based liquids and glasses. The hypersonic sound velocity, refractive index and attenuation coefficient obtained using Brillouin light scattering spectroscopy technique were in agreement with literature data. From the measured sound velocities, the pressure dependence of the bulk moduli and density of liquid water were calculated, using Vinet equation of state. The formalism was extended to the Brillouin scattering studies of the elastic properties of alkaline-calcium silica hydrogels and float glass, which exhibits a dramatic increase in the pressure dependence of longitudinal velocity and a discontinuity in the compressibility at about 6 GPa. It is demonstrated that an apparent second-order transition to a new amorphous phase can form via the abrupt onset of a new compressional mechanism, which may be triggered by a shift in polymerization of the glass or an onset of a change in coordination of silicon. Brillouin scattering measurements were carried out on an aqueous solution of Na2O-2SiO2 and anhydrous Na2O-2SiO 2 glass and liquid at high P-T conditions. The "modified" platelet scattering geometry has allowed a determination of the longitudinal velocity independently from refractive index, and hence the adiabatic compressibility and density of liquids as a function of pressure and temperature. The observed increase in density of the melt and glass phases formed at high P-T conditions is likely associated with structural effects. The large values of KS' of the liquid phase illustrate that the means of compaction of the liquid differs substantially from that of the glass, and that the liquid is able to access a wider range of compaction mechanisms. The measured bulk modulus of Na2O-2SiO2 aqueous solution is closer to values of silicate melts than to that of end-member water at

  11. Catalyst: and solvent-free synthesis of imidazo[1,2-a]pyridines

    OpenAIRE

    Zhu,Dong-Jian; Chen,Jiu-Xi; Liu,Miao-Chang; Ding,Jin-Chang; Wu,Hua-Yue

    2009-01-01

    A highly efficient and facile method has been described for the synthesis of imidazo[1,2-a]pyridines in good to excellent yields by condensation of the α-haloketones (ArCOCHXR², Ar = C6H5, 4-MeOC6H4, 4-ClC6H4, 2,4-Cl2C6H3; X = Br, Cl; R² = H, CH3) with 2-aminopyridines without the use of any additional catalyst and solvent.

  12. Bis(imidazo[1,2-a]pyridin-1-ium tetrachloridocuprate(II dihydrate

    Directory of Open Access Journals (Sweden)

    Sonia Mokaddem

    2017-02-01

    Full Text Available In the title salt, (C7H7N22[CuCl4]·2H2O, the Cu2+ cation is coordinated by four Cl atoms and adopts a distorted tetrahedral geometry. Two molecules of imidazo[1,2-a]pyridine are protonated ensuring electrical neutrality. O—H...Cl and N—H...O hydrogen bonds link the organic and the inorganic moieties, leading to a self-organized hydrated hybrid structure.

  13. Dichloridobis[2-methyl-sulfanyl-4-(pyridin-2-yl)pyrimidine-κN,N]cobalt(II).

    Science.gov (United States)

    Yang, Wen-Na

    2011-09-01

    The asymmetric unit of the title compound, [CoCl(2)(C(10)H(9)N(3)S)(2)], contains one half-mol-ecule with the Co(II) atom situtated on a twofold rotational axis. The Co(II) atom, in an octa-hedral enviroment, is coordinated by four N atoms from two 2-methyl-sulfanyl-4-(pyridin-2-yl)pyrimidine ligands and two Cl atoms.

  14. Catalyst: and solvent-free synthesis of imidazo[1,2-a]pyridines

    OpenAIRE

    Zhu,Dong-Jian; Chen,Jiu-Xi; Liu,Miao-Chang; Ding,Jin-Chang; Wu,Hua-Yue

    2009-01-01

    A highly efficient and facile method has been described for the synthesis of imidazo[1,2-a]pyridines in good to excellent yields by condensation of the α-haloketones (ArCOCHXR², Ar = C6H5, 4-MeOC6H4, 4-ClC6H4, 2,4-Cl2C6H3; X = Br, Cl; R² = H, CH3) with 2-aminopyridines without the use of any additional catalyst and solvent.

  15. {2,2′-[Pyridine-3,4-diylbis(nitrilomethylidyne]diphenolato}zinc(II

    Directory of Open Access Journals (Sweden)

    Ning Sheng

    2009-11-01

    Full Text Available The title compound, [Zn(C19H13N3O2], has been synthesized by the reaction of Zn(ClO42·6H2O and the tetradentate Schiff base ligand 2,2′-[pyridine-3,4-diylbis(nitrilomethylidyne]diphenol (L. The coordination geometry of the ZnII ion is slightly distorted square-planar, formed by two N atoms and two O atoms from the L ligand.

  16. 2-[1-(9-Anthrylmethyl-1H-pyrazol-3-yl]pyridine

    Directory of Open Access Journals (Sweden)

    Shi-Lu Zhang

    2009-11-01

    Full Text Available The title compound, C23H17N3, can be used in coordination chemistry. The anthracene ring makes dihedral angles of 86.08 (5 and 76.63 (6°, respectively, with the pyridine and pyrazole rings. The dihedral angle between the pyrazole and pyrimidine rings is 11.79 (7°. In the structure, weak intermolecular C—H...N hydrogen bonds are observed.

  17. Synthesis, Reactivity and Stability of Aryl Halide Protecting Groups towards Di-Substituted Pyridines

    Directory of Open Access Journals (Sweden)

    Ptoton Mnangat Brian

    2016-03-01

    Full Text Available This paper reports the synthesis and reactivity of different Benzyl derivative protecting groups. The synthesis and stability of Benzyl halides, 4-methoxybenzyl halides, 3,5-dimethoxybenzyl halides, 3,4-dimethoxybenzyl halides, 3,4,5-trimethoxybenzyl halide protecting groups and their reactivity towards nitrogen atom of a di-substituted pyridine ring in formation of pyridinium salts is also reported.

  18. Catalytic wet peroxidation of pyridine bearing wastewater by cerium supported SBA-15

    Energy Technology Data Exchange (ETDEWEB)

    Subbaramaiah, V. [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand (India); Srivastava, Vimal Chandra, E-mail: vimalcsr@yahoo.co.in [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand (India); Mall, Indra Deo [Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand (India)

    2013-03-15

    Highlights: ► Cerium supported SBA-15 (Ce/SBA-15) synthesized by two-step synthesis. ► Characterization of Ce/SBA-15 by FTIR, XRD and BET surface area. ► Catalytic peroxidation of pyridine by Ce/SBA-15. ► Optimization of parameters like catalyst dose, H{sub 2}O{sub 2} dose, initial concentration and temperature. ► Catalyst reusability and leaching study performed. -- Abstract: Cerium supported SBA-15 (Ce/SBA-15) was synthesized by two-step synthesis method in acidic medium. It was further characterized by various characterization techniques such as X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy and N{sub 2} adsorption–desorption pore size distribution analysis. The Ce/SBA-15 showed highly ordered meso-structure with pore diameter ≈ 70–100 A and pore volume ≈ 0.025 cm{sup 3}/g. Ce/SBA-15 was further evaluated as a catalyst for the oxidation of highly toxic and non-biodegradable material, pyridine, by catalytic wet-peroxidation method. The effects of various operating parameters such as catalyst dose (0.5–6 g/l), stoichiometric ratio of H{sub 2}O{sub 2}/pyridine (1–6), initial pyridine concentration (50–800 mg/l) and temperature (313–358 K) have been evaluated and optimized. Ce/SBA-15 showed stable performance during reuse for six cycles with negligible cerium leaching. Kinetic and thermodynamic parameters and operation cost have also been determined.

  19. Mixed Pyridine-phenol Boron Complex Encapsulated in Polymer/Silica Hybrid Sol-gel Matrix

    Institute of Scientific and Technical Information of China (English)

    DONG Wei; TANG Jun; WANG Yue

    2008-01-01

    A novel pyridine-phenol boron complex[(dppy)BF]was encapsulated into polymer/silica composite matrix by sol-gel process.UV-Vis absorption spectra show that this process can control the aggregation structure of complex(dppy)BF.The results of photoluminescence of(dppy)BF in sol-gel composite film indicate that both fluorescence intensity and photostability are markedly increased using this method compared with other methods,which increases the practical significance of such composite film.

  20. Crystal structures of the solvates of diethylaminogossypol with ethyl acetate and pyridine

    Science.gov (United States)

    The crystal structures of diethylaminogossypol with ethyl acetate (DEAG-EA) and pyridine (DEAG-P) were studied by room-temperature X-ray diffraction. The host-to-guest molecule ratio in these complexes is 2:1 for DEAG-EA and 2:5 for DEAG-P. The crystal and cell parameters for DEAG-EA are C34H40N2O6...

  1. Palladium-Catalyzed Suzuki-Miyaura Type Coupling Reaction of Aryl Halides with Triphenylborane-Pyridine

    Institute of Scientific and Technical Information of China (English)

    杨明华; 顾勇冰; 王艳; 赵玺玉; 严国兵

    2012-01-01

    The Suzuki-Miyaura type coupling reaction of aryl halides with triphenylborane-pyridine was described. The reaction can be catalyzed by Pd(OAc)2 (5 mol%) in presence of Cs2CO3 at 50 ℃ or 80 ℃, and functionalized biaryls were obtained in good to excellent yields. This protocol is general and can tolerate a wide range of func- tional groups.

  2. The Effect of Xe Underlayers on the Surface Enhanced Raman Scattering of Pyridine on Cold Silver.

    Science.gov (United States)

    1984-11-01

    enhancement effect on deposited pyridine can be dramatically reduced. ~Present address: INIFTA, Division Fisicoquimica de Superficies, CC 16, * Suc...is increased beyond 70K we see dramatic increases in peaks for all four - quadrant. See Figure 3. Certain structural changes begin to take place at...this stage. One such changes is the beginning of appreciable sublimation of the physisorbed Xe, even out of the pores. 18 Another change might involve

  3. Pyridine ring opening at room temperature at a rhenium tricarbonyl bipyridine complex.

    Science.gov (United States)

    Huertos, Miguel A; Pérez, Julio; Riera, Lucía

    2008-04-30

    Pyridine ring opening occurs in the reaction of [Re(CO)3(MeIm)(bipy)]OTf with KN(SiMe3)2 followed by double methylation with methyl trifluoromethanesulfonate. Analogues of the neutral product of the initial deprotonation and of the product of the first methylation were isolated by using mesitylimidazole (MesIm) in place of methylimidazole (MeIm) and/or 1,10-phenanthroline (phen) instead of 2,2'-bipyridine (bipy).

  4. (E-4-Methoxy-3,5-dimethyl-2-[(3-nitrophenylethenyl]pyridine

    Directory of Open Access Journals (Sweden)

    Youness El Bakri

    2016-12-01

    Full Text Available In the crystal of the title compound, C16H16N2O3, weak C—H...O hydrogen bonds involving the nitro group as acceptor form chains extending in the b-axis direction. The chains are arranged into layers by π–π stacking interactions along the c-axis direction between the substituted pyridine rings, separated by 3.624 (1 Å.

  5. (E-Benzaldehyde O-{[3-(pyridin-3-ylisoxazol-5-yl]methyl}oxime

    Directory of Open Access Journals (Sweden)

    Rodolfo Moreno-Fuquen

    2012-04-01

    Full Text Available The asymmetric unit of the title compound, C16H13N3O2, contains two independent molecules in which the pyridine and benzene rings form dihedral angles of 81.7 (2 and 79.8 (2°, indicating the twist in the molecules. In the crystal, weak C—H...N interactions link molecules into chains along [100].

  6. Ab initio MO study on equilibrium bond distance between Fe and pyridine in bis(pyridine)(porphinato) iron for various electronic states

    Science.gov (United States)

    Saito, Minoru; Kashiwagi, Hiroshi

    1985-04-01

    For bis(pyridine)(porphinato) iron [FeP(py)2], a correlation between the iron electronic state and the equilibrium Fe-Npy distance was investigated. Potential energy curves as a function of the Fe-Npy distance were calculated for low-spin, intermediate-spin, and high-spin states of the ferric and ferrous ions by the ab initio SCF MO method. The equilibrium Fe-Npy distances were obtained from the potential curves. The values obtained for the ferric low-spin and high-spin states were in good agreement with the experimental values for Fe(III)(OEP)(3-Clpy)2 within the differences, ±0.05 Å. The following significant features were found. The equilibrium distance is elongated by the occupation of the 3dz2 orbital and is shortened by the oxidation of the iron atom. The distance and the force constant for the symmetrical py-Fe-py stretching are strongly correlated with the overlap population between the 3dz2 orbital and pyridine-nitrogen orbitals.

  7. catena-Poly[[[iodidocopper(I]-{μ-N-[(pyridin-2-yl-κNmethylidene]pyridin-3-amine-κ2N3:N1}] acetonitrile hemisolvate

    Directory of Open Access Journals (Sweden)

    Ali Mahmoudi

    2012-10-01

    Full Text Available In the asymmetric unit of the title polymeric complex, {[CuI(C11H9N3]·0.5CH3CN}n, there are two CuI atoms, two N-[(pyridin-2-yl-κNmethylidene]pyridin-3-amine (PyPy ligands and two I atoms. Both CuI atoms have a distorted tetrahedral geometry, each being coordinated by one I atom, two N atoms of one PyPy ligand and one N atom from an adjacent PyPy ligand. In the crystal, infinite helical chains of [Cu2(PyPy2]n are formed propagating along the b axis. These chains are linked via weak C—H...I hydrogen bonds and π–π stacking interactions [shortest centroid–centroid distance = 3.2727 (14 Å]. During the refinement, electron-density peaks were located that were believed to be highly disordered solvent molecules (possibly acetonitrile. The SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155] indicated there were solvent cavities with a total volume of 196 Å3 containing approximately 60 electrons per unit cell, which equated to one molecule of acetonitrile per asymmetric unit.

  8. Poly[[tetraaquatetrakis[μ3-5-(pyridine-4-carboxamidoisophthalato]cobalt(IIdigadolinium(III] tetrahydrate

    Directory of Open Access Journals (Sweden)

    Dai-Zhi Kuang

    2011-10-01

    Full Text Available In the centrosymmetric polymeric title compound, {[CoGd2(C14H8N2O54(H2O4]·4H2O}n, the GdIII cation is coordinated by one water molecule and four pyridine-4-carboxamidoisophthalate (L anions in a distorted square-antiprismatic arrangement, while the CoII cation, located on an inversion center, is coordinated by two pyridyl-N atoms, two carboxylate-O atoms and two water molecules in a distorted octahedral geometry. The asymmetric unit contains two anionic L ligands: one bridges two Gd cations and one Co cation through two carboxyl groups and one pyridine-N atom; the other bridges two Gd cations and one Co cation through two carboxyl groups and the uncoordinated pyridine-N atom is hydrogen-bonded to the adjacent coordinated water molecule. Extensive O—H...O and N—H...O hydrogen bonds are present in the crystal structure.

  9. Study on the structure and morphology of supramolecular shape memory polyurethane containing pyridine moieties

    Science.gov (United States)

    Chen, S. J.; Hu, J. L.; Chen, S. G.; Zhang, C. L.

    2011-06-01

    Fabricating smart materials has been an attractive research topic in recent years. In this study, a series of pyridine-containing shape memory polyurethanes (Py-SMPUs) with different pyridine contents were synthesized. Based on the theoretical analysis, the structure and morphology of Py-SMPUs were studied systematically with FT-IR, DSC, WAXD, DMA, AFM, etc. Results show that a hydrogen-bonded supramolecular structure is formed in the Py-SMPUs. Hydrogen bonds present in the urethane group and pyridine ring are the most favorable hydrogen bonds which play an important role in the movement of the polymer chain. Microphase separation consisting of a soft phase and hard phase occurs in the Py-SMPUs. The soft phase is influenced greatly by the N, N-bis(2-hydroxyl ethyl) isonicotinamide (BINA) unit and the hard phase is mainly a result of the hexamethylene diisocyanate and 1,4-butanediol (HDI-BDO) units. As the BINA content decreases, the soft phase tends to change gradually from a continuous amorphous phase to a droplet-like dispersion phase, whereas the hard phase develops from a droplet-like dispersion amorphous phase to a continuous crystalline phase.

  10. POLYAMIDES WITH PENDANT 1,3,4-OXADIAZOLE AND PYRIDINE MOIETIES

    Institute of Scientific and Technical Information of China (English)

    Yagoub Mansoori; Behzad Koohi-Zargar; Hemayat Shekaari; Mohammad Reza Zamanloo; Gholam Hassan Imanzadeh

    2012-01-01

    A novel aromatic diamine,2-(5-(3,5-diaminophenyl)-1,3,4-oxadiazole-2-yl)pyridine (POBD),containing a pyridine ring and a 1,3,4-oxadiazole moiety,was synthcsized.It was used in a polycondensation with various aromatic and aliphatic diacid chlorides to generate a series of new aromatic polyamides with pendant 1,3,4-oxadiazole groups.The prepared polyamides were characterized by IR,elemental analysis and through the synthesis of model compounds.Thermophysical properties of the synthesized polyamides have been studied by DSC,TGA and inherent viscosity measurements.Relatively high inherent viscosity values (0.76-1.62 dL/g,in 0.125% H2SO4 at 25℃) were observed for these compounds.Number average molecular weight (Mn) of the polymers was measured by vapor phase osmometry (VPO).The introduction of bulky side chains in the structure of aromatic polyamides led to increased solubility of these polymers in common polar and aprotic solvents,such as DMF,DMSO,NMP and DMAc,which allowed thin films to be cast from polymer solutions.The highest molecular weight (Mn =51190) was observed for polymer (Ⅸ),which was prepared from pyridine-2,6-dichlorocarbonyl.

  11. Role of vanadium and pyridine in heteropolycompounds for selective oxidation of alcohols with hydrogen peroxide

    Indian Academy of Sciences (India)

    Valeria Palermo; Paula I Villabrille; Patricia G Vázquez; Carmen V Cáceres; Pietro Tundo; Gustavo P Romanelli

    2013-11-01

    This study describes the application of heteropolyacids H3PMo12O40,H4SiMo12O40, H4PMo11VO40, H5PMo10V2O40, H9PMo6V6O40, and a hybrid pyridine-modified heteropolyacid with Keggin structure for selective oxidation of alcohols to ketones or aldehydes using aqueous hydrogen peroxide and acetonitrile as solvent. Performance of these different catalysts in 1-phenylethanol oxidation was studied. Influence of reaction temperature, amount of catalyst and hydrogen peroxide and reaction time on the yield of acetophenone was investigated to obtain optimal reaction conditions. Oxidation ability of the catalyst depended on the number of vanadium atoms present in the Keggin ion and to a lesser extent on pyridine substitution in the Keggin secondary structure. In order to explore the applicability of the method for selective oxidation of alcohols to ketones or aldehydes, various alcohols were investigated according to the general procedure using hybrid pyridine-modified heteropolyacid.

  12. Fluorescent property of 3-hydroxymethyl imidazo[1,2-a]pyridine and pyrimidine derivatives

    Directory of Open Access Journals (Sweden)

    Velázquez-Olvera Stephania

    2012-08-01

    Full Text Available Abstract Background Imidazo[1,2-a]pyridines and pyrimidines are important organic fluorophores which have been investigated as biomarkers and photochemical sensors. The effect on the luminescent property by substituents in the heterocycle and phenyl rings, have been studied as well. In this investigation, series of 3-hydroxymethyl imidazo[1,2-a]pyridines and pyrimidines were synthesized and evaluated in relation to fluorescence emission, based upon the hypothesis that the hydroxymethyl group may act as an enhancer of fluorescence intensity. Results Compounds of both series emitted light in organic solvents dilutions as well as in acidic and alkaline media. Quantitative fluorescence spectroscopy determined that both fused heterocycles fluoresced more intensely than the parent unsubstituted imidazo[1,2-a]azine fluorophore. In particular, 3-hydroxymethyl imidazo[1,2-a]pyridines fluoresced more intensely than 3-hydroxymethyl imidazo[1,2-a]pyrimidines, the latter emitting blue light at longer wavelengths, whereas the former emitted purple light. Conclusion It was concluded that in most cases the hydroxymethyl moiety did act as an enhancer of the fluorescence intensity, however, a comparison made with the fluorescence emitted by 2-aryl imidazo[1,2-a]azines revealed that in some cases the hydroxymethyl substituent decreased the fluorescence intensity.

  13. Benzene-pyridine interactions predicted by the effective fragment potential method.

    Science.gov (United States)

    Smith, Quentin A; Gordon, Mark S; Slipchenko, Lyudmila V

    2011-05-12

    The accurate representation of nitrogen-containing heterocycles is essential for modeling biological systems. In this study, the general effective fragment potential (EFP2) method is used to model dimers of benzene and pyridine, complexes for which high-level theoretical data -including large basis spin-component-scaled second-order perturbation theory (SCS-MP2), symmetry-adapted perturbation theory (SAPT), and coupled cluster with singles, doubles, and perturbative triples (CCSD(T))-are available. An extensive comparison of potential energy curves and components of the interaction energy is presented for sandwich, T-shaped, parallel displaced, and hydrogen-bonded structures of these dimers. EFP2 and CCSD(T) potential energy curves for the sandwich, T-shaped, and hydrogen-bonded dimers have an average root-mean-square deviation (RMSD) of 0.49 kcal/mol; EFP2 and SCS-MP2 curves for the parallel displaced dimers have an average RMSD of 0.52 kcal/mol. Additionally, results are presented from an EFP2 Monte Carlo/simulated annealing (MC/SA) computation to sample the potential energy surface of the benzene-pyridine and pyridine dimers.

  14. Redetermination of pyridine-4-carbonitrile–chloranilic acid (1/1 at 180 K

    Directory of Open Access Journals (Sweden)

    Hiroyuki Ishida

    2008-07-01

    Full Text Available In the crystal structure of the title compound, C6H4N2·C6H2Cl2O4, two chloranilic acid (systematic name: 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone molecules are connected by O—H...O hydrogen bonds to form a dimeric unit. The pyridine-4-carbonitrile molecules are linked on both sides of the dimer via N...H...O hydrogen bonds to give a centrosymmetric 2:2 complex of pyridine-4-carbonitrile and chloranilic acid. The H atom in the N...H...O hydrogen bond is disordered over two positions with approximately equal occupancies. The pyridine ring makes a dihedral angle of 61.54 (14° with the chloranilic acid plane. The 2:2 units are further linked by intermolecular C—H...O and C—H...Cl hydrogen bonds. This determination presents a siginficantly higher precision crystal structure than the previously published structure [Tomura & Yamasshita (2008. X-ray Struct. Anal. Online, 24, x31–x32].

  15. A Pyridine-copper Inclusion Complex of a New Tripodal Ligand

    Institute of Scientific and Technical Information of China (English)

    范承; 马成丙; 陈昌源; 陈锋; 刘秋田

    2003-01-01

    A pyridine-copper inclusion complex with [Cu(py)4Cl]+ core was prepared in the presence of tripodal ligand tbst {tbst = 1,3,5-tris(2-benzimidazol)sulfanylmethyl-2,4,6-trimethyl- benzene}, and its structure has been determined. It crystallizes in triclinic, space group Pī with a = 9.0822(2), b = 17.6026(4), c = 18.7156(4)(A°),α= 93.40,β= 91.2980(1),γ= 91.5560(1)°, V = 2984.81(1)(A°)3, C58H63Cl2CuN11O4S3, Mr = 1208.81, Z = 2, F(000) = 1262, Dc = 1.345 g/cm3,β= 0.615 mm-1, R = 0.0713 and wR = 0.1307 for 7798 observed reflections (I > 2σ(1)). X-ray analysis reveals that the uncoordinated tbst and pyridine as guest molecules are included in the complex with formula {[Cu(py)4Cl]Cl}@(tbst)@(py)@4H2O. The tbst, pyridine, aqua and Cl- anion in the com- plex form extensive hydrogen-bonding interactions, building up a quasi-dinuclear structure.

  16. Catalytic wet peroxidation of pyridine bearing wastewater by cerium supported SBA-15.

    Science.gov (United States)

    Subbaramaiah, V; Srivastava, Vimal Chandra; Mall, Indra Deo

    2013-03-15

    Cerium supported SBA-15 (Ce/SBA-15) was synthesized by two-step synthesis method in acidic medium. It was further characterized by various characterization techniques such as X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy and N2 adsorption-desorption pore size distribution analysis. The Ce/SBA-15 showed highly ordered meso-structure with pore diameter≈70-100Ǻ and pore volume≈0.025cm(3)/g. Ce/SBA-15 was further evaluated as a catalyst for the oxidation of highly toxic and non-biodegradable material, pyridine, by catalytic wet-peroxidation method. The effects of various operating parameters such as catalyst dose (0.5-6g/l), stoichiometric ratio of H2O2/pyridine (1-6), initial pyridine concentration (50-800mg/l) and temperature (313-358K) have been evaluated and optimized. Ce/SBA-15 showed stable performance during reuse for six cycles with negligible cerium leaching. Kinetic and thermodynamic parameters and operation cost have also been determined.

  17. Highly efficient non-doped blue organic light emitting devices based on anthracene–pyridine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Haykir, Gulcin; Tekin, Emine; Atalar, Taner; Türksoy, Figen

    2013-12-02

    Four different 2-(10-aryl)anthracen-9-yl)pyridine derivatives 5a–d were synthesized via the Suzuki cross-coupling reaction. Photo-physical characteristics of these materials having strong electron donating or electron withdrawing groups were explored. Multilayer small molecule organic light emitting diodes without any dopant were fabricated in the following sequence: Indium tin oxide/4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (50 nm)/5a–d (30 nm)/4,7-diphenyl-1,10-phenanthroline (30 nm)/LiF/Al. The electroluminescent property of the device fabricated with 5d as an emitter exhibited a high external quantum efficiency of 3.80% (at around 1 mA/cm{sup 2}) with Commission Internationale De L'Eclairage coordinates of (0.14, 0.25). - Highlights: • Synthesis and characterization of 2-(10-aryl)anthracen-9-yl)pyridine derivatives • Thermal, photophysical and electrochemical properties of anthracene derivatives • Emitters from blue to greenish blue for organic light emitting device applications • Organic light emitting device fabrication and characterization of 2-(10-aryl)anthracen-9-yl)pyridine derivatives.

  18. Synthesis and Characterization of Polyamide-Containing 2, 6-(Substituded) pyridine Derivatives

    Institute of Scientific and Technical Information of China (English)

    XU Kuoxi; HU Peizhi; CAI Lihua

    2006-01-01

    A new series of acyclic aromatic polyamide pyridine derivatives a-h and a new macrocyclic polyamide containing pyri dine ring I were synthesized by the reaction of N2 , N6-bis (2-aminoethyl) pyridine-2,6-dicarboxamide or N2 , N6-bis ( 3-aminopropyl) pyridine-2,6-dicarboxamide with various acyl chloride.The compounds were characterized by MS, 1H NMR,IR and elemental analysis. The single-crystal structure of g confirmed that the crystal is of triclinic, space group P-1 with Mr =487.55, a=9.303 1(19), b=12.167(2) , c=126.50(3) nm,a=108.91(3)°, β=97.57(3)°, γ=102.07(3)°, V=1 293.5nm, Z=2, D() =1. 252 kg/m3,μ=0.086 mm-1 , F(000) =516. X-ray analysis reveals that there exist hydrogen bonding and network structure in the crystal.

  19. Etude de la variation de transmission optique dans l'UltraViolet du quartz "Nippon Silica Glass" après expositions à des rayonnements - Etude du système d'acquisition de données et du système de contrôle de Hautes Tensions appliquées aux chambres à fils du BARREL RICH de DELPHI

    CERN Document Server

    Delorme, Sophie

    1992-01-01

    Etude de la variation de transmission optique dans l'UltraViolet du quartz "Nippon Silica Glass" après expositions à des rayonnements - Etude du système d'acquisition de données et du système de contrôle de Hautes Tensions appliquées aux chambres à fils du BARREL RICH de DELPHI

  20. Research Progress on the Synthesis of Energetic Pyridines%吡啶类含能化合物的合成研究进展

    Institute of Scientific and Technical Information of China (English)

    马丛明; 刘祖亮; 许晓娟; 姚其正

    2014-01-01

    吡啶类化合物在含能材料领域中的研究和应用较为广泛。从分子结构出发,按照硝基吡啶、吡啶类含能离子盐和吡啶类含能配合物分类,综述了多种吡啶硝基衍生物的合成,并简单介绍了一些重要的硝基吡啶类含能化合物的特性及主要应用。%Pyridines are widely used in energetic materials. Based on molecular structure, and classified themselves by nitro-pyridines, pyridine-based energetic salts, pyridine-based energetic complexes, a large number of energetic pyridines are sum-marized. The characteristics and main applications of some important energetic pyridines are also introduced briefly.

  1. Etude spectroscopique des noyaux riches en protons dans la region 22 < Z < 28 et T$_(Z)$ < -3/2

    OpenAIRE

    Dossat, Cedric

    2004-01-01

    La region des noyaux riches en protons tels que 22 < Z < 28 et T$_(Z)$ < -3/2 a pu etre etudiee de maniere tres detaillee grace a trois experiences menees au GANIL entre 1999 et 2002 : cette etude porte sur 23 isotopes allant du $^(39)$Ti au $^(53)$Ni. Nous avons mesure pour la premiere fois les durees de vie du $^(43)$V, du $^(51)$Ni et du $^(51)$Co, et considerablement ameliore la precision de celles deja connues. De nouvelles transitions par emission de protons et de rayonnement $\\gamma$ o...

  2. Photochemical activation of ruthenium(II)-pyridylamine complexes having a pyridine-N-oxide pendant toward oxygenation of organic substrates.

    Science.gov (United States)

    Kojima, Takahiko; Nakayama, Kazuya; Sakaguchi, Miyuki; Ogura, Takashi; Ohkubo, Kei; Fukuzumi, Shunichi

    2011-11-09

    Ruthenium(II)-acetonitrile complexes having η(3)-tris(2-pyridylmethyl)amine (TPA) with an uncoordinated pyridine ring and diimine such as 2,2'-bipyridine (bpy) and 2,2'-bipyrimidine (bpm), [Ru(II)(η(3)-TPA)(diimine)(CH(3)CN)](2+), reacted with m-chloroperbenzoic acid to afford corresponding Ru(II)-acetonitrile complexes having an uncoordinated pyridine-N-oxide arm, [Ru(II)(η(3)-TPA-O)(diimine)(CH(3)CN)](2+), with retention of the coordination environment. Photoirradiation of the acetonitrile complexes having diimine and the η(3)-TPA with the uncoordinated pyridine-N-oxide arm afforded a mixture of [Ru(II)(TPA)(diimine)](2+), intermediate-spin (S = 1) Ru(IV)-oxo complex with uncoordinated pyridine arm, and intermediate-spin Ru(IV)-oxo complex with uncoordinated pyridine-N-oxide arm. A Ru(II) complex bearing an oxygen-bound pyridine-N-oxide as a ligand and bpm as a diimine ligand was also obtained, and its crystal structure was determined by X-ray crystallography. Femtosecond laser flash photolysis of the isolated O-coordinated Ru(II)-pyridine-N-oxide complex has been investigated to reveal the photodynamics. The Ru(IV)-oxo complex with an uncoordinated pyridine moiety was alternatively prepared by reaction of the corresponding acetonitrile complex with 2,6-dichloropyridine-N-oxide (Cl(2)py-O) to identify the Ru(IV)-oxo species. The formation of Ru(IV)-oxo complexes was concluded to proceed via intermolecular oxygen atom transfer from the uncoordinated pyridine-N-oxide to a Ru(II) center on the basis of the results of the reaction with Cl(2)py-O and the concentration dependence of the consumption of the starting Ru(II) complexes having the uncoordinated pyridine-N-oxide moiety. Oxygenation reactions of organic substrates by [Ru(II)(η(3)-TPA-O)(diimine)(CH(3)CN)](2+) were examined under irradiation (at 420 ± 5 nm) and showed selective allylic oxygenation of cyclohexene to give cyclohexen-1-ol and cyclohexen-1-one and cumene oxygenation to afford cumyl alcohol

  3. Phosphine-Free Palladium-Catalyzed Direct C-3 Arylation of 2-Phenylimidazo[1,2-a]pyridine Using Silver(I Carboxylate

    Directory of Open Access Journals (Sweden)

    Sridevi Kona

    2013-01-01

    Full Text Available Phosphine-free palladium-catalyzed direct arylation of 2-phenyl-imidazo[1,2-a]pyridine has been developed with the concept of using silver(I carboxylate. This protocol efficiently catalyzes the C-H arylation of 2-phenyl-imidazo[1,2-a]pyridine with aryl iodides to afford the corresponding 2-phenyl-3-aryl-imidazo[1,2-a]pyridines in moderate to-good yields.

  4. The effect of an anti-hydrogen bond on Fermi resonance:A Raman spectroscopic study of the Fermi doublet v1-v12 of liquid pyridine

    Institute of Scientific and Technical Information of China (English)

    Li Dong-Fei; Gao Shu-Qin; Sun Cheng-Lin; Li Zuo-Wei

    2012-01-01

    The effects of an anti-hydrogen bond on the v1-v12 Fermi resonance (FR) of pyridine are experimentally investigated by using Raman scattering spectroscopy.Three systems,pyridine/water,pyridine/formamide,and pyridine/carbon tetrachloride,provide varying degrees of strength for the diluent-pyridine anti-hydrogen bond complex.Water forms a stronger anti-hydrogen bond with pyridine than with formamide,and in the case of adding non-polar solvent carbon tetrachloride,which is neither a hydrogen bond donor nor an acceptor and incapable of forming a hydrogen bond with pyridine,the intermolecular distance of pyridine will increase and the interaction of pyridine molecules will reduce.The dilution studies are performed on the three systems.Comparing with the values of the Fermi coupling coefficient W of the ring breathing mode v1 and triangle mode v12 of pyridine at different volume concentrations,which are calculated according to the Bertran equations,in three systems,we find that the solution with the strongest anti-hydrogen bond,water,shows the fastest change in thev1-v12 Fermi coupling coefficient W with the volume concentration varying,followed by the formamide and carbon tetrachloride solutions.These results suggest that the stronger anti-hydrogen bond-forming effect will cause a greater reduction in the strength of the v1-v12 FR of pyridine.According to the mechanism of the formation of an anti-hydrogen bond in the complexes and the FR theory,a qualitative explanation for the anti-hydrogen bond effect in reducing the strength of the v1 - v12 FR of pyridine is given.

  5. Correlated Nitrogen and Carbon Anomalies in an Anhydrous Interplanetary Dust Particle - Implications for Extraterrestrial Organic Matter Accreted by the Prebiotic Earth

    Energy Technology Data Exchange (ETDEWEB)

    Floss, C; Stadermann, F J; Bradley, J P; Dai, Z; Bajt, S; Graham, G

    2003-12-17

    Given the ubiquitous presence of H and N isotopic anomalies in interplanetary dust particles (IDPs) and their probable association with carbonaceous material, the lack of similar isotopic anomalies in C has been a major conundrum. We report here the first observation of correlated N and C isotopic anomalies in organic matter within an anhydrous IDP. The {sup 15}N composition of the anomalous region is the highest seen to date in an IDP and is accompanied by a moderate depletion in {sup 13}C. Our observations establish the presence of hetero-atomic organic compounds of presolar origin among the constant flux of carbonaceous material accreting to the terrestrial planets within IDPs. Theoretical models suggest that low temperature formation of organic compounds in cold interstellar molecular clouds does produce C and N fractionations, but it remains to be seen if these models can reproduce the specific effects we observe here.

  6. LIQUID-LIQUID EQUILIBRIUM FOR TERNARY SYSTEMS CONTAINING ETHYLIC BIODIESEL + ANHYDROUS ETHANOL + REFINED VEGETABLE OIL (SUNFLOWER OIL, CANOLA OIL AND PALM OIL: EXPERIMENTAL DATA AND THERMODYNAMIC MODELING

    Directory of Open Access Journals (Sweden)

    T. P. V. B. Dias

    2015-09-01

    Full Text Available AbstractPhase equilibria of the reaction components are essential data for the design and process operations of biodiesel production. Despite their importance for the production of ethylic biodiesel, the reaction mixture, reactant (oil and ethanol and the product (fatty acid ethyl esters up to now have received less attention than the corresponding systems formed during the separation and purification phases of biodiesel production using ethanol. In this work, new experimental measurements were performed for the liquid-liquid equilibrium (LLE of the system containing vegetable oil (sunflower oil and canola oil + ethylic biodiesel of refined vegetable oil + anhydrous ethanol at 303.15 and at 323.15 K and the system containing refined palm oil + ethylic biodiesel of refined palm oil + ethanol at 318.15 K. The experimental data were successfully correlated by the nonrandom two-liquid (NRTL model; the average deviations between calculated and experimental data were smaller than 1.00%.

  7. Brucine salts of L-alpha-hydroxy acids: brucinium hydrogen (S)-malate pentahydrate and anhydrous brucinium hydrogen (2R,3R)-tartrate at 130 K.

    Science.gov (United States)

    Smith, Graham; Wermuth, Urs D; White, Jonathan M

    2006-06-01

    The structures of two brucinium (2,3-dimethoxy-10-oxostrychnidinium) salts of the alpha-hydroxy acids L-malic acid and L-tartaric acid, namely brucinium hydrogen (S)-malate pentahydrate, C23H27N2O4+.C4H5O5-.5H2O, (I), and anhydrous brucinium hydrogen (2R,3R)-tartrate, C23H27N2O4+.C4H5O6-,(II), have been determined at 130 K. Compound (I) has two brucinium cations, two hydrogen malate anions and ten water molecules of solvation in the asymmetric unit, and forms an extensively hydrogen-bonded three-dimensional framework structure. In compound (II), the brucinium cations form the common undulating brucine sheet substructures, which accommodate parallel chains of head-to-tail hydrogen-bonded tartrate anion species in the interstitial cavities.

  8. Thermal evaporation-induced anhydrous synthesis of Fe3O4-graphene composite with enhanced rate performance and cyclic stability for lithium ion batteries.

    Science.gov (United States)

    Dong, Yucheng; Ma, Ruguang; Hu, Mingjun; Cheng, Hua; Yang, Qingdan; Li, Yang Yang; Zapien, Juan Antonio

    2013-05-21

    We present a high-yield and low cost thermal evaporation-induced anhydrous strategy to prepare hybrid materials of Fe3O4 nanoparticles and graphene as an advanced anode for high-performance lithium ion batteries. The ~10-20 nm Fe3O4 nanoparticles are densely anchored on conducting graphene sheets and act as spacers to keep the adjacent sheets separated. The Fe3O4-graphene composite displays a superior battery performance with high retained capacity of 868 mA h g(-1) up to 100 cycles at a current density of 200 mA g(-1), and 539 mA h g(-1) up to 200 cycles when cycling at 1000 mA g(-1), high Coulombic efficiency (above 99% after 200 cycles), good rate capability, and excellent cyclic stability. The simple approach offers a promising route to prepare anode materials for practical fabrication of lithium ion batteries.

  9. Transformations of 3-hydroxy steroids with lewis and anhydrous protic acids: the case of pregn-4-en-3β,17α,20β-triol.

    Science.gov (United States)

    De Marco, Rosaria; Leggio, Antonella; Liguori, Angelo; Perri, Francesca; Siciliano, Carlo

    2011-08-01

    The acid-catalyzed dehydration is one of the most important processes, which transforms 3-hydroxy steroids into their corresponding unsaturated derivatives. This reaction is of great importance because it can produce molecules that play a key role in the understanding of the natural metabolism of steroids. Sterol dehydration is generally performed with aqueous acidic systems, and the treatment often affords low yields of the desired compounds and/or complex mixtures of by-products. In this paper, we report the results obtained from the study of the structural and stereochemical effects of the acid-induced reaction of pregn-4-en-3β,17α,20β-triol in anhydrous systems. In particular, the treatment of this trihydroxy steroid model with Lewis acids leads to the corresponding Δ(3,5) -steradiene as the only product and in very high yields. With Lewis acids, no modifications of the 1,2-diol function on the D-ring are observed, even when the reactions are performed at high temperatures. Protic acid catalysis in non-aqueous organic solvents causes the formation of an epimeric mixture of the corresponding Δ(3,5) -steradiene derivatives by a partial stereochemical inversion of the asymmetric C-17. The reactivity of the 17α,20β-diolic residue is also evaluated by exposing pregn-4-en-3β,17α,20β-triol and the corresponding Δ(3,5) -steradiene to the prolonged action of anhydrous protic acid systems under thermal conditions. © 2011 John Wiley & Sons A/S.

  10. Investigation of the anhydrous molten Na-B-O-H system and the concept: Electrolytic hydriding of sodium boron oxide species

    Energy Technology Data Exchange (ETDEWEB)

    Calabretta, Daniel L.; Davis, Boyd R. [Queen' s-RMC Fuel Cell Research Centre, Kingston, Ont. (Canada); Kingston Process Metallurgy, Inc., 1102 Lancaster Dr., Kingston, Ont. (Canada); Department of Mining Engineering, Queen' s University, 25 Union Ave., Kingston, Ont. (Canada)

    2007-02-10

    Although sodium borohydride (NaBH{sub 4}) can act as an excellent hydrogen storage material, its cost renders it impractical for automotive applications. In this paper the concept of electrolytic production of NaBH{sub 4} from sodium metaborate (NaBO{sub 2}) is introduced following a literature review of NaBH{sub 4} synthesis. By deduction, we assert that only by employing dense solid oxide ion electrolytes and a molten salt solution containing the two constituents would such a process be possible. We investigated the molten anhydrous Na-B-O-H system by pressure differential thermal analysis (PDTA), X-ray diffraction (XRD) and gas evolution analysis (GEA) using the starting reagents sodium hydride (NaH), NaBO{sub 2} and NaBH{sub 4}. We found that molten NaBH{sub 4} is not stable with NaBO{sub 2} above 600 C due to the formation of sodium orthoborate (Na{sub 4}B{sub 2}O{sub 5}), hydrogen and boron. However, the quasi-reciprocal ternary system, (4/5)NaH-NaBO{sub 2}-(1/5)NaBH{sub 4}-(2/5)Na{sub 4}B{sub 2}O{sub 5}, that was discovered, proves that molten Na{sub 4}B{sub 2}O{sub 5} is miscible and stable with molten NaBH{sub 4} to at least 650 C under the hydrogen pressures used in this study. As well, the compound Na{sub 6}B{sub 2}O{sub 5}H{sub 2} was discovered and a substantial portion of the anhydrous Na-B-O-H phase diagram has been experimentally deduced. There is a large ionic liquid composition domain within the system that would allow for the electrolytic hydriding of sodium boron oxide species to be tested. (author)

  11. Investigation of the anhydrous molten Na-B-O-H system and the concept: Electrolytic hydriding of sodium boron oxide species

    Science.gov (United States)

    Calabretta, Daniel L.; Davis, Boyd R.

    Although sodium borohydride (NaBH 4) can act as an excellent hydrogen storage material, its cost renders it impractical for automotive applications. In this paper the concept of electrolytic production of NaBH 4 from sodium metaborate (NaBO 2) is introduced following a literature review of NaBH 4 synthesis. By deduction, we assert that only by employing dense solid oxide ion electrolytes and a molten salt solution containing the two constituents would such a process be possible. We investigated the molten anhydrous Na-B-O-H system by pressure differential thermal analysis (PDTA), X-ray diffraction (XRD) and gas evolution analysis (GEA) using the starting reagents sodium hydride (NaH), NaBO 2 and NaBH 4. We found that molten NaBH 4 is not stable with NaBO 2 above 600 °C due to the formation of sodium orthoborate (Na 4B 2O 5), hydrogen and boron. However, the quasi-reciprocal ternary system, (4/5)NaH-NaBO 2-(1/5)NaBH 4-(2/5)Na 4B 2O 5, that was discovered, proves that molten Na 4B 2O 5 is miscible and stable with molten NaBH 4 to at least 650 °C under the hydrogen pressures used in this study. As well, the compound Na 6B 2O 5H 2 was discovered and a substantial portion of the anhydrous Na-B-O-H phase diagram has been experimentally deduced. There is a large ionic liquid composition domain within the system that would allow for the electrolytic hydriding of sodium boron oxide species to be tested.

  12. Thermal properties and structural characterizations of new types of phase change material: Anhydrous and hydrated palmitic acid/camphene solid dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tu, E-mail: tulee@cc.ncu.edu.tw; Chiu, Yu Hsiu; Lee, Yun; Lee, Hung Lin

    2014-01-10

    Highlights: • Solid dispersion is implemented on phase change materials. • Water is added as a tertiary component. • Specific heat of solid is increased by partially amorphous camphene. • Microstructures are characterized by LTDSC, PXRD and SAXS. • Thermal properties are linked to microstructures. - Abstract: Two new types of phase change material anhydrous and hydrated palmitic acid/camphene solid dispersions (PA1CA1) are prepared and characterized by low-temperature differential scanning calorimetry, powder X-ray diffraction, small-angle X-ray scattering and temperature–history method. Their microstructures contain nanometer-sized palmitic acid (PA) crystallites with lamellar periodicity dispersed in a partially amorphous plastic crystalline camphene (CA) matrix. The PA phase apparently possesses a relatively high latent heat value inherited from the pristine crystalline PA of 229.7 ± 0.1 kJ kg{sup −1}. The relatively high specific heat of solid, C{sub ps}, for anhydrous PA1CA1 of 2.17 ± 0.06 kJ kg{sup −1} K{sup −1} is originated from the presence of disordered CA matrix. Hydration of PA1CA1 can further increase the C{sub ps} to 2.61 ± 0.01 kJ kg{sup −1} K{sup −1}. The mixing of partially amorphous CA, some PA and the small amount of water may have turned the matrix into more disorder due to their different bonding natures, molecular weights, and various molecular shapes and sizes.

  13. Preparation and study of dialkyl nitroxide radicals; Preparation et etude de radicaux nitroxydes diacyles

    Energy Technology Data Exchange (ETDEWEB)

    Chenavas, P. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [French] Ces radicaux sont obtenus par oxydation d'imides N-hydroxyles par le tetracetate de plomb ou l'acide p-nitroperbenzoique; ces imides sont prepares par chauffage d'anhydrides de diacides en presence de benzyloxyamine suivie d'une hydrogenation catalytique des N-benzyloxyimides ainsi obtenus. Deux series de radicaux ont principalement ete etudies: la premiere relative a des imides cycliques a cinq chainons, la seconde a des imides cycliques a six chainons, ces molecules ayant des substituants methyles ou non sur la chaine carbonee. Les derives O-benzyles de quelques-uns de ces imides ont ete analyses en R. M. N. Ces differents resultats ont permis une etude de la conformation et de la stereochimie de ces imides. (auteur)

  14. Alecto 2 - interaction studies; Alecto 2 - etudes d'interaction

    Energy Technology Data Exchange (ETDEWEB)

    Brunet, J.P.; Clouet d' Orval, Ch.; Mougniot, J.C.; Penet, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Weak interactions were experimentally studies with the tank of the critical assembly Alecto II and one, two or three bottles containing solutions of various concentrations. In particular, was studied the validity of certain classical assumptions, shielding effects, screening and semi-reflexion effects, importance of thermal coupling. The method of the 'k{sub eff}, solid angle' is shown to apply to such a system. The determination by divergence and pulsed neutron technique of the reactivity related to a millimeter of solution level affords the obtention of critical heights in terms of reactivity. (authors) [French] Une etude experimentale d'interactions faibles a ete faite entre la cuve de l'experience critique ALECTO II et une, deux ou trois bouteilles contenant des concentrations variees. On etudie, en particulier, la validite de certaines hypotheses classiques, effets d'ombre, d'ecrans, de semi-reflexion, importance du couplage thermique. On montre d'autre part que la methode du 'K{sub eff}, angle solide' peut s'appliquer a un tel systeme. La determination par divergence et neutrons pulses de la reactivite liee au millimetre de solution permet de traduire les hauteurs critiques obtenues, en terme de reactivite. (auteurs)

  15. 练习曲中的童话画面%The Fairy Tale Pictures in Etudes

    Institute of Scientific and Technical Information of China (English)

    刘铭

    2011-01-01

    The two sets of Etudes-Tableaux op33 and op39 are the most important and most repre- sentative works in Rachmaninoff's piano music as well as a perfect eornbination of art and technique. Selecting the well-known and most representative op39no6 Little Red Riding Hood and the Wolf, this paper analyses the visualization of pictures from the music and its playing techniques, hoping to shed light on its performance and teaching.%音画练习曲op33和op39是拉赫玛尼诺夫钢琴音乐创作中最重要且最具代表性的作品之一.也是艺术性和技术性的完美结合体。选取著名的并最有代表性的op39n06《小红帽与野狼》,从音乐的画面性和演奏的技巧性两方面进行分析,以期在演奏与教学方面得到启发。

  16. Scientific Opinion on the safety and efficacy of betaine (betaine anhydrous and betaine hydrochloride as a feed additive for all animal species based on a dossier submitted by VITAC EEIG

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-05-01

    Full Text Available Glycine betaine (betaine acts as a methyl group donor in transmethylation reactions in organisms. Betaine occurs in numerous vertebrate tissues as an osmolyte, ensuring osmoprotection. Betaine is safe for piglets at the maximum supplementation rate of 2 000 mg/kg complete feed with a margin of safety below 5. This conclusion is extended to all pigs and extrapolated to all animal species and categories. The use of betaine anhydrous and betaine hydrochloride as feed additives up to a supplementation rate of 2 000 mg betaine/kg complete feed is unlikely to pose concerns for consumer safety. In the absence of data, betaine anhydrous and betaine hydrochloride should be considered hazardous by inhalation, as irritant to skin, eyes and mucous membranes, and skin sensitisers. The supplementation of feed with betaine anhydrous and betaine hydrochloride does not pose a risk to the environment. Betaine has the potential to become efficacious in all animal species and categories when administered via feed or water for drinking. Betaine anhydrous and betaine hydrochloride are considered as nutritionally equivalent sources of betaine. The FEEDAP Panel made some recommendations on (i introduction of a maximum content for supplemental betaine in complete feed and water for drinking; (ii avoidance of simultaneous use of betaine in feed and water for drinking; (iii avoidance of simultaneous inclusion of betaine and choline chloride in premixtures; and (iv protection of users when handling the additives.

  17. X-ray Structures of Precursors of Styrylpyridine-Derivatives Used to Obtain 4-((E)-2-(Pyridin-2-yl)vinyl)benzamido-TEMPO: Synthesis and Characterization

    OpenAIRE

    Guillermo Soriano-Moro; María Judith Percino; Ana Laura Sánchez; Víctor Manuel Chapela; Margarita Cerón; María Eugenia Castro

    2015-01-01

    The synthesis and characterization of the precursor isomers trans-4-(2-(pyridin-2-yl)vinylbenzaldehyde (I), trans-4-(2-(pyridin-4-yl)vinylbenzaldehyde (II), trans-4-(2-(pyridin-2-yl)vinylbenzoic acid (III) and (E)-4-(2-(pydridin-4-yl)vinylbenzoic acid (IV) are reported. These compounds were prepared in order to obtain trans-4-((E)-2-(pyridin-2-yl)vinyl)benzamide-TEMPO (V). Compounds I and II were obtained by using a Knoevenagel reaction in the absence of a condensing agent and solvent. Oxidat...

  18. Synthesis of Diethyl Pyridin-2-ylphosphonates and Quinolin-2-ylphosphonates by Deoxygenative Phosphorylation of the Corresponding N-Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sangjin; Kim, Hyunsoo; Yang, Haewon; Yoo, Byungwoo; Yoon, Cheol Min [Korea Univ., Seoul (Korea, Republic of)

    2014-07-15

    The reaction of pyridine N-oxide and quinoline N-oxide activated by ethyl chloroformate with triethyl phosphites at rt gave the corresponding diethyl pyridin-2-ylphosphonate and diethyl quinolin-2-ylphosphonate regio-selectively in good to excellent yield through oxygenative phosphorylation. The reaction condition is mild and efficient compared to the reported methods. All chemicals including commercially available pyridine N-oxides were purchased from specialized suppliers with analytical purity and used without further purification. Non commercially available pyridine N-oxide for the reaction were prepared by known method. IR spectra of products were recorded on a Perkin-Elmer FT-IR 240-c spectrometer using KBr disks. {sup 1}H NMR (300 MHz) and {sup 13}C NMR (75 MHz) spectra were recorded on a Bruker 300 spectrometer in CDCl{sub 3}. High-resolution ESI-MS spectra were obtained on an IT-TOF (Shimadzu, Japan) at Korea Basic Science Institute (KBSI). Column chromatography was performed using Merck silica gel (230-400 mesh). Some known products have physical, spectroscopic, and analytic data identical to those (shown as a CAS registry number) given in the literature. Dialkyl pyridin-2-ylphosphonates widely used as corrosion inhibitors, dispersing and emulsifying agents, antistatics and lubricant additives in various technological fields are known as potent insecticides, fungicides and herbicides. Pyridin-2-ylphosphonates have also been reported to have a promising cytokinin activity, anti-proliferating and antiplatelet activating factor (anti-PAF) activities, and to be used as a chelate ligand to prepare various metal-organic frameworks, such as polymeric material with Zn, Cd and Ag showing luminescence properties, iron complex as a catalyst and copper complex with weak ferromagnetism. Because biological properties of dialkyl pyridin-2-ylphosphonates and physical properties of their complexes depend both on the phosphorus-containing ligand, simple and efficient

  19. Crystal structure of [2,6-di­fluoro-3-(pyridin-2-yl-κN)pyridin-4-yl-κC 4](pentane-2,4-dionato-κ2 O,O′)platinum(II)

    Science.gov (United States)

    Park, Ki-Min; Lee, Jieun; Kang, Youngjin

    2015-01-01

    The asymmetric unit of the title compound, [Pt(C10H5F2N2)(C5H7O2)], comprises one PtII atom, one 2,6-di­fluoro-2,3-bi­pyridine ligand and one acetyl­acetonate anion. The PtII atom adopts a distorted square-planar coordination geometry, being C,N-chelated by the 2,6-di­fluoro-3-(pyridin-2-yl)pyridin-4-yl ligand and O,O′-chelated by the pentane-2,4-dionate ligand. The two pyridine rings of the bi­pyridine ligand are approximately coplanar, making a dihedral angle of 1.2 (2)°. A variety of intra- and inter­molecular C—H⋯O and C—H⋯F hydrogen bonds, as well as π–π inter­actions [centroid–centroid distances = 4.337 (3) and 3.774 (3) Å] contribute to the stabilization of the mol­ecular and crystal structures, and result in the formation of a three-dimensional supra­molecular framework. PMID:26029388

  20. Crystal structure of [2,6-di-fluoro-3-(pyridin-2-yl-κN)pyridin-4-yl-κC (4)](pentane-2,4-dionato-κ(2) O,O')platinum(II).

    Science.gov (United States)

    Park, Ki-Min; Lee, Jieun; Kang, Youngjin

    2015-04-01

    The asymmetric unit of the title compound, [Pt(C10H5F2N2)(C5H7O2)], comprises one Pt(II) atom, one 2,6-di-fluoro-2,3-bi-pyridine ligand and one acetyl-acetonate anion. The Pt(II) atom adopts a distorted square-planar coordination geometry, being C,N-chelated by the 2,6-di-fluoro-3-(pyridin-2-yl)pyridin-4-yl ligand and O,O'-chelated by the pentane-2,4-dionate ligand. The two pyridine rings of the bi-pyridine ligand are approximately coplanar, making a dihedral angle of 1.2 (2)°. A variety of intra- and inter-molecular C-H⋯O and C-H⋯F hydrogen bonds, as well as π-π inter-actions [centroid-centroid distances = 4.337 (3) and 3.774 (3) Å] contribute to the stabilization of the mol-ecular and crystal structures, and result in the formation of a three-dimensional supra-molecular framework.

  1. Etude des etats electroniques en champ magnetique dans le niveau de Landau N=0 de la tricouche ABC de graphene

    Science.gov (United States)

    Rondeau, Maxime

    Dans cet ouvrage nous etudions les phases du gaz d'electrons bidimensionnel dans la tricouche de graphene en empilement ABC. En partant du modele des liaisons fortes et en faisant l'approximation du continuum autour des vallees K +, K-, nous obtenons un modele effectif a deux bandes qui permet de decrire la physique de basse energie des electrons en champ magnetique dans cette structure. Ce modele contient trois orbitales degenerees dans le niveau de Landau N = O. Ce dernier est donc 12N φ, fois degeneres en incluant les degres de liberte de spin et de vallee. En ajoutant l'interaction de Coulomb au systeme et en considerant seulement les remplissages v = -5, -4, -4, 5 afin d'avoir un systeme a trois niveaux, nous etudions le diagramme de phase du gaz d'electrons en fonction d'un biais electrique entre les couches externes. Nous trouvons une phase d'onde de densite de charge bidimensionnelle (ODC2D) comme etat fondamental du systeme. Cette ODC2D se nomme cristal dans ce memoire et nous derivons ses proprietes de transports et ses modes collectifs. Nous discutons egalement du caractere topologique de ce cristal. Notre etude englobe aussi les phases liquides avec ou sans coherence orbitale. Nous concluons notre memoire par l'etude de quelques signatures experimentales des phases du gaz d'electrons dans la tricouche.

  2. Two isostructural carbamates: the o-tolyl N-(pyridin-3-yl)carbamate and 2-bromo-phenyl N-(pyridin-3-yl)carbamate monohydrates.

    Science.gov (United States)

    Mocilac, Pavle; Gallagher, John F

    2015-11-01

    The title carbamate monohydrates, C13H12N2O2·H2O and C12H9BrN2O2·H2O, form isomorphous crystals that are isostructural in their primary hydrogen-bonding modes. In both carbamates, the primary hydrogen bonding and aggregation involves cyclic amide-water-pyridine moieties as (N-H⋯O-H⋯N)2 dimers about inversion centres [as R 4 (4)(14) rings], where the participation of strong hydrogen-bonding donors and acceptors is maximized. The remaining water-carbonyl O-H⋯O=C inter-action extends the aggregation into two-dimensional planar sheets that stack parallel to the (100) plane. The Br derivative does not participate in halogen bonding. A weak intra-molecular C-H⋯O hydrogen bond is observed in each compound.

  3. Synthesis of Eu(Ⅲ) and Tb(Ⅲ) complexes with novel pyridine dicarboxylic acid derivatives and their fluorescence properties

    Institute of Scientific and Technical Information of China (English)

    Tang Ruiren; Yan Zi'er; Guo Cancheng; Luo Yiming

    2006-01-01

    Starting from pyridine-2,6-dicarboxylic acid (DPA),a series of novel pyridine-2,6-dicarboxylic acid derivatives were synthesized.In these compounds,4-(hydroxymethyl)pyridine-2,6-dicarboxylate (4-HMDPA) and 4-[(bis-carboxymethyl-amino)-methyl] -pyridine-2,6-dicarboxylic acid (4-BMDPA) were used as multifunctional ligands to coordinate with Tb(Ⅲ) and Eu(Ⅲ) and the complexes were prepared.The fluorescence properties of the solid complexes and their solutions were investigated in detail.The results indicated that the weak election-withdrawing group 4-hydroxymethyl in 4-position of pyridine in 4-HMDPA could weaken the fluorescence intensity of the lanthanide complexes.The contradistinctive experimental results showed that the fluorescence intensities of these complexes are related to pH values of the aqueous solutions and the dipole moments of solvent molecules:in the neutral aqueous solutions,the fluorescence intensities of these complexes were strongest,while the dipole moments were lower when the fluorescence intensifies were stronger.4-BMDPA is the better sensitizer and may be used as time-resolved fluoroimmunoassay.

  4. Association of symmetrical alkane diols with pyridine: DFT/GIAO calculation of (1) H NMR chemical shifts.

    Science.gov (United States)

    Lomas, John S; Joubert, Laurent; Maurel, François

    2016-05-31

    Proton nuclear magnetic resonance (NMR) shifts of the free diol and of its 1 : 1 and 1 : 2 hydrogen-bonded complexes with pyridine have been computed for five symmetrical alkane diols on the basis of density functional theory, by applying the gauge-including atomic orbital method to geometry-optimized conformers. For certain conformers, intramolecular OH···OH interactions, evidenced by high NMR OH proton shifts, are further enhanced on going from the free diol to the corresponding 1 : 1 diol/pyridine complex. This is confirmed by atoms-in-molecules and non-covalent interaction plots. The computed OH and CH proton shifts for the diol and the two complexes correlate well with values obtained by analysing data from the NMR titration of the diols in benzene against pyridine. Shift values for the diols in neat pyridine are calculated by weighting the shifts of the various protons in the three forms (free diol, 1 : 1 and 1 : 2 diol/pyridine complexes) according to the experimentally determined association constants. The results are in good agreement with those observed, and after empirical scaling, the root mean square difference is 0.18 ppm. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Catalytic Hydrogenation Activity and Electronic Structure Determination of Bis(arylimidazol-2-ylidene)pyridine Cobalt Alkyl and Hydride Complexes

    Science.gov (United States)

    Yu, Renyuan Pony; Darmon, Jonathan M.; Milsmann, Carsten; Margulieux, Grant W.; E. Stieber, S. Chantal; DeBeer, Serena

    2013-01-01

    The bis(arylimidazol-2-ylidene)pyridine cobalt methyl complex, (iPrCNC)CoCH3, was evaluated for the catalytic hydrogenation of alkenes. At 22 °C and 4 atm of H2 pressure, (iPrCNC)CoCH3 is an effective pre-catalyst for the hydrogenation of sterically hindered, unactivated alkenes such as trans-methylstilbene, 1-methyl-1-cyclohexene and 2,3-dimethyl-2-butene, representing one of the most active cobalt hydrogenation catalysts reported to date. Preparation of the cobalt hydride complex, (iPrCNC)CoH was accomplished by hydrogenation of (iPrCNC)CoCH3. Over the course of 3 hours at 22 °C, migration of the metal-hydride to the 4-position of the pyridine ring yielded (4-H2-iPrCNC)CoN2. Similar alkyl migration was observed upon treatment of (iPrCNC)CoH with 1,1-diphenylethylene. This reactivity raised the question as to whether this class of chelate is redoxactive, engaging in radical chemistry with the cobalt center. A combination of structural, spectroscopic and computational studies was conducted and provided definitive evidence for bis(arylimidazol-2-ylidene)pyridine radicals in reduced cobalt chemistry. Spin density calculations established that the radicals were localized on the pyridine ring, accounting for the observed reactivity and suggest a wide family of pyridine-based pincers may also be redox active. PMID:23968297

  6. Bis(pyridine-κN{N2,N2′-[1,1′-(pyridine-2,6-diyldiethylidyne]benzenesulfonohydrazonato-κ5O,N,N′,N′′,O′}nickel(II

    Directory of Open Access Journals (Sweden)

    Juahir Yusnita

    2010-02-01

    Full Text Available In the crystal structure of the title compound, [Ni(C21H19N5O4S2(C5H5N2], the metal center is seven-coordinate, with an approximate pentagonal-bipyramidal configuration. The Ni atom is chelated by a dianionic pentadentate Schiff base via the pyridine N atom, the two azomethine N atoms and the two sulfonyl O atoms. The latter coordinate to Ni at different distances, viz. 2.3337 (12 and 2.7988 (12 Å. Two apically coordinated pyridine molecules complete the seven-coordinate geometry. The dihedral angle between the two pyridine ring planes is 68.25 (6°.

  7. Synthesis of a Bis(thiophenolate)pyridine Ligand and Its Titanium, Zirconium, and Tantalum Complexes

    KAUST Repository

    Lenton, Taylor N.

    2012-11-12

    A precursor to a new tridentate LX 2 type ligand, bis(thiophenol)pyridine ((SNS)H 2 = (2-C 6H 4SH) 2-2,6-C 5H 3N), was prepared. Bis(thiophenolate)pyridine complexes of Ti, Zr, and Ta having dialkylamido coligands were synthesized and structurally characterized. The zirconium complex (SNS)Zr(NMe 2) 2 (4) displays C 2 symmetry in the solid state, unlike a related bis(phenolate)pyridine compound, C s-symmetric (ONO)Ti(NMe 2) 2. This change is likely the result of strain about the sulfur atom in the six-membered chelate with longer metal-sulfur and carbon-sulfur bonds. Solid-state structures of tantalum complexes (SNS)Ta(NMe 2) 3 (5) and (SNS)TaCl(NEt 2) 2 (6) also display pronounced C 2 twisting of the SNS ligand. 1D and 2D NMR experiments show that 5 is fluxional, with rotation about the Ta-N(amide) bonds occurring on the NMR time scale that interchange the equatorial amide methyl groups (ΔG ‡ 393 = 25.0(3) kcal/mol). The fluxional behavior of 6 in solution was also studied by variable-temperature 1H NMR. Observation of separate signals for the diastereotopic protons of the methylene unit of the diethylamide indicates that the complex remains locked on the NMR time scale in one diastereomeric conformation at temperatures below -50 °C, fast rotation about the equatorial amide Ta-N bonds occurs at higher temperature (ΔG ‡ 393 = 13.4(3) kcal/mol), and exchange of diastereomeric methylene protons occurs via inversion at Ta that interconverts antipodes (ΔG ‡ 393 ≈ 14(1) kcal/mol). © 2012 American Chemical Society.

  8. Synthesis and Crystal Structure of [Copper(1,10-phenanthroline)2(pyridine)]perchlorates

    Institute of Scientific and Technical Information of China (English)

    牛德仲; 路再生; 马恒俊; 孙柏旺

    2001-01-01

    The complex [Cu(phen)2py](ClO4)2 was obtained by the reaction of 1,10-phenanthroline with Cu(C1O4)2·6H2O in water and by recrystallization from pyridine. A single-crystal X-ray study shows that the complex is a square pyramidal arrangement of five nitrogen atoms from the two 1,10-phenanthroline ligands and one pyridine ligand, respectively.The compound is orthorhombic, C29H21N5C12O8Cu, Mr = 701.958, with space group Pbcn,α = 29.9593(3), b = 16.1240(3), c = 11.9183(6)A, V= 5757.3(3)A3, Z = 8, Dc= 1.409g/cm3,μ =1.121 mm-1, F(000) = 2465, R = 0.0539, Rw = 0.1380 for 4293 reflections with I>2 σ(I). The bond lengths of Cu(1)-N(1), Cu(1)-N(2), Cu(1)-N(3) and Cu(1)-N(4) are 2.223(3),2.017(3), 2.013(3) and 2.038(3) A, respectively. The distance from copper to pyridine N(5) is 2.012(3) A. The angles N(2)-Cu(1)-N(3) and N(4)-Cu(1)-N(5) are 176.1(1)°and 160.9(1)°,respectively. The angles between axial position nitrogen atom N(1) and four square position nitrogen atoms N(2), N(3), N(4), N(5) are 79.3(1), 98.3(1), (1),108.4(1)°,respectively.

  9. Lignocellulosic-derived modified agricultural waste: development, characterisation and implementation in sequestering pyridine from aqueous solutions.

    Science.gov (United States)

    Ahmed, Md Juned K; Ahmaruzzaman, M; Reza, Ruhul A

    2014-08-15

    The development and characterisation of modified agricultural waste (MAW) by H3PO4 activation is addressed in this study for sequestering pyridine from aqueous solutions. The adsorbent is characterised by carbon, hydrogen and nitrogen content of 55.53%, 3.28% and 0.98% respectively. The adsorbent also shows acidic (carboxylic, lactonic, phenolic groups) and basic carbon surface functionalities, functional groups viz. hydroxyl, carboxylic acid and bounded water molecules, BET surface area of 1254.67 m(2) g(-1), heterogeneous surface morphology and graphite like XRD patterns. Adsorption of pyridine is executed to evaluate the adsorptive uptake in batch (q(e)=107.18 mg g(-1)) as well as in column system (q(e)=140.94 mg g(-1)). The adsorption process followed the pseudo-second-order kinetics with the Langmuir isotherm best representing the equilibrium adsorption data. The thermodynamic parameters (ΔH(o)=9.39 kJ mol(-1), ΔG(o)=-5.99 kJ mol(-1), ΔS(o)=50.76 J K(-1) mol(-1)) confirm the endothermic and spontaneous nature of the adsorption process with increase in randomness at solid/solution interface. The adsorption mechanism is governed by electrostatic and π-π dispersive interactions as well as by a two stage diffusion phenomena. Thermally regenerated spent MAW exhibited better adsorption efficiency for five adsorption-desorption cycles than chemically regenerated. The low-cost of MAW (USD 10.714 per kg) and favourable adsorption parameters justifies its use in the adsorptive removal of pyridine.

  10. Contribution to the study of french pitchblendes; Contribution a l'etude des pechblendes francaises

    Energy Technology Data Exchange (ETDEWEB)

    Geffroy, J. [Commissariat a l' Energie Atomique, Lab. de Mineralogie, Centre de Chatillon (France). Centre d' Etudes Nucleaires; Sarcia, J.A. [Commissariat a l' Energie Atomique, Div. de la Crouzille, Haute Vienne (France). Centre d' Etudes Nucleaires

    1955-07-01

    The authors first review the characteristics of uraninite-pitchblende, as deduced of present literature. They set apart from typical pitchblende a black oxide aspect, which probably corresponds to neo-formations, and a 'para-pitchblende' aspect, which they relate to deep sur-oxidation of normal pitchblende. They insist on the easy replacement of pitchblende by silica. and give indications as to changes in vein stones (fluorite, quartz, etc...). A detailed study of paragenesis and successions in french uranium districts follows (including discussion of uranium of uranium-bearing coals). The authors attempt to classify french pitchblende veins. They are chiefly epithermal and poor in satellite ores. Three types of deposits are identified: massive - pitchblende type, silica type, fluorite type. These deposits, as those of Portugal, are included in granite, Central-European peri-batholitic types where uranium associates which Ni, Co, Bi and Ag, are in France both rare and poor. Finally, the authors attempt to bring out in the european Hercynian area a particular distribution of paragenetic types. (authors) [French] Les auteurs recapitulent d'abord les caracteres et les occurences de l'uraninite - pechblende, tels qu'ils peuvent etre degages de l'actuelle bibliographie. Ils exposent ensuite les faits qui du point de vue mineralogique seulement ressortent de l'etude mineralogique et chalcographique des pechblendes francaises et de leurs satellites. Ils distinguent de la pechblende-type un facies oxyde noir; correspondant probablement a une neoformation, et un facies parapechblende, qui est rapporte a une sur oxydation hypogene de la pechblende proprement dite. Ils insistent sur le facile remaniement de la pechblende par la slice; et donnent quelques precisions sur les modifications des gangues (fluorine, quartz, etc...). Suit l'etude detaillee des parageneses et des successions dans les districts uraniferes francais: Divisions du

  11. Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

    Directory of Open Access Journals (Sweden)

    Matthias Böttger

    2012-07-01

    Full Text Available The compounds 6-(pyrrol-2-yl-2,2‘-bipyridine, 2-(pyrrol-2-yl-1,10-phenanthroline and 2-(2-(N-methylbenz[d,e]imidazole-6-(pyrrol-2-yl-pyridine were synthesized by using an in situ generated boronic acid for the Suzuki coupling. Crystals of the products could be grown and exhibited interesting structures by X-ray analysis, one of them showing a chain-like network with the adjacent molecules linked to each other via intermolecular N–H…N hydrogen bonds.

  12. Bis(2-hydroxy-N′-isopropylidenebenzohydrazidato-κ2N′,Obis(pyridine-κNcobalt(II

    Directory of Open Access Journals (Sweden)

    Xiaojuan Zhao

    2009-04-01

    Full Text Available In the title complex, [Co(C10H11N2O22(C5H5N2], the CoII atom lies on a centre of symmetry and adopts a distorted cis-CoO2N4 octahedral geometry. The two acetone salicyloylhydrazone ligands are deprotonated and act as N,O-bidentate monoanionic ligands, forming the equatorial plane, while the axial positions are occupied by two N atoms of two pyridine molecules. The complex presents O—H...N and C—H...N intramolecular hydrogen bonds. Intermolecular C—H...N and C—H...O interactions are also present in the crystal.

  13. Butylbis(diphenylglyoximato(pyridine-κNcobalt(IIIThis article is dedicated to late Professor B. D. Gupta.

    Directory of Open Access Journals (Sweden)

    Sarvendra Kumar

    2012-02-01

    Full Text Available In the title compound, [Co(C4H9(C14H11N2O22(C5H5N], the CoIII atom is coordinated by a butyl group, a nitrogen-bonded pyridine and two N,N′-bidentate diphenylglyoximate ligands in a distorted octahedral geometry. The crystal structure features two short O—H...O bridges between the two chelating anions, with O...O distances less than 2.5 Å.

  14. Tetra-μ-acetato-bis[(pyridine N-oxidecopper(II](Cu—Cu

    Directory of Open Access Journals (Sweden)

    Ya-Bo Xie

    2009-08-01

    Full Text Available The molecule of the title binuclear copper(II complex, [Cu2(CH3COO4(C5H5NO2], occupies a special position on a crystallographic inversion centre; the coordination environment of the CuII atom is slightly distorted square-pyramidal and is made up of four O atoms belonging to four acetate groups in the basal plane with the O atom of pyridine N-oxide ligand in the apical position. The Cu—Cu distance is 2.6376 (6 Å.

  15. Synthesis, antibacterial, and antiviral evaluation of new heterocycles containing the pyridine moiety.

    Science.gov (United States)

    Salem, Marwa S; Sakr, Sameh I; El-Senousy, Waled M; Madkour, Hassan M F

    2013-10-01

    A facile one-pot four-component reaction was utilized to construct 2-oxo-1,2-dihydropyridine-3-carbonitrile as a scaffold for the synthesis of many fused heterocyclic systems, namely, furopyridine, pyridothiadiazepinthione, and pyridotriazine, as well as non-fused heterocyclic systems such as phthalazin-2(1H)-ylnicotinonitrile, pyridin-2-yl-1H-pyrazole, and pyrazol-1-ylnicotino-nitrile,1-(3-cyanopyridin-2-yl)-1H-pyrazole. The new compounds were evaluated as antimicrobial and antiviral agents.

  16. Synthesis of modified pyridine and bipyridine substituted coumarins as potent antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Lad Hemali B.

    2015-01-01

    Full Text Available In search for new antimicrobial agents a series of new modified pyridine and bipyridine substituted coumarins 5a-y was designed and synthesized by adopting molecular hybridization strategy. All the synthesized compounds were evaluated for their in vitro antimicrobial activity using broth dilution method against selected bacterial (Gram-positive and Gram-negative and fungal strains. Compounds 5a, 5f, 5g, 5n, 5r, 5t, 5w, 5x and 5y demonstrated promising antibacterial activity while other derivatives showed comparable activity to standard drugs used as reference.

  17. Oxidation Reactivity Channels for 2-(Pyridin-2-yl)-N,N-diphenyl-acetamides

    Energy Technology Data Exchange (ETDEWEB)

    Pailloux, Sylvie [University of New Mexico, Albuquerque; Binyamin, Iris [University of New Mexico, Albuquerque; Kim, Sung-jun [University of New Mexico, Albuquerque; Deck, Lorraine M. [University of New Mexico, Albuquerque; Rapko, Brian M. [Pacific Northwest National Laboratory (PNNL); Hay, Benjamin [ORNL; Duesler, Eileen N. [University of New Mexico, Albuquerque; Paine, Robert T. [University of New Mexico, Albuquerque

    2007-11-01

    Synthetic routes to 2-(pyridin-2-yl)-N,N-diphenylacetamide and 2-(6-methylpyridin-2-yl)-N,N-diphenyl-acetamide are described along with results from the chemical oxidation of these compounds with peracetic acid, m-chloroperbenzoic acid, and OXONE. In each case, oxidations generate four products in varying amounts depending on the oxidant and reaction conditions. Each product has been characterized by spectroscopic methods and the molecular structures of several of the new compounds have been confirmed by X-ray crystallography.

  18. Oxidation reactivity channels for 2-(pyridin-2-yl)-N,N-diphenylacetamides

    Energy Technology Data Exchange (ETDEWEB)

    Pailloux, Sylvie; Binyamin, Iris; Deck, Lorraine M.; Rapko, Brian M.; Hay, Benjamin P.; Duesler, Eileen N.; Paine, Robert T.

    2007-11-01

    Synthetic routes to 2-(pyridin-2-yl)-N,N-diphenylacetamide and 2-(6-methylpyridin-2-yl)-N,N-diphenylacetamide are described along with results from the chemical oxidation of these compounds with peracetic acid, m-chloroperbenzoic acid, and OXONE. In each case, oxidations generate four products in varying amounts depending on the oxidant and reaction conditions. Each product has been characterized by spectroscopic methods and the molecular structures of several of the new compounds have been confirmed by X-ray crystallography.

  19. catena-Poly[[bis(pyridine-3-carboxylic acid-κNmercury(II]-di-μ-chlorido

    Directory of Open Access Journals (Sweden)

    Sadif A. Shirvan

    2012-04-01

    Full Text Available In the title compound, [HgCl2(C6H5NO22]n, the HgII cation is located on an inversion center and is six-coordinated in a distorted octahedral geometry by two N atoms from two pyridine-3-carboxylic acid molecules and four bridging Cl− anions. The bridging function of the Cl− anions leads to polymeric chains running along the a axis. One Hg—Cl bond is much longer than the other. In the crystal, O—H...O and weak C—H...Cl hydrogen bonds are observed.

  20. fac-Tris(pyridine-2-carboxylato-κ2N,Ocobalt(III

    Directory of Open Access Journals (Sweden)

    Irina A. Golenia

    2011-11-01

    Full Text Available In the title compound, [Co(C6H4NO23], the CoIII ion lies on a threefold rotation axis and is in a distorted octahedral environment defined by three N and three O donor atoms from three fac-disposed pyridine-2-carboxylate ligands. The ligands are coordinated in a chelate fashion, forming three five-membered rings. In the crystal, translationally related complex molecules are organized into columns along [001] via C—H...O hydrogen bonds.

  1. Bis[μ-3,5-bis(pyridin-2-ylpyrazolato]bis[(hexafluorophosphatocopper(II

    Directory of Open Access Journals (Sweden)

    Satoshi Kawata

    2013-08-01

    Full Text Available The title dinuclear complex molecule, [Cu2(C13H9N42(PF62], lies about an inversion center. The CuII atom shows a square-pyramidal coordination geometry with the basal plane formed by four N atoms of the two bis-chelating 3,5-bis(pyridin-2-ylpyrazolate ions and with one F atom of the hexafluorophosphate ion in the apical position. Molecules are stacked in a column along the a axis through C—H...F hydrogen bonds. The columns are further linked by other C—H...F hydrogen bonds, forming a three-dimensional network.

  2. A pyridine-functionalized pyrazolinofullerene used as a buffer layer in polymer solar cells.

    Science.gov (United States)

    Yang, Pingao; Chen, Shan; Liu, Yu; Xiao, Zuo; Ding, Liming

    2013-10-28

    A pyridine-functionalized pyrazolinofullerene (1) was synthesized in 42% yield via an improved one-pot reaction of C60, 3,6-di(2-pyridyl)-1,2,4,5-tetrazine, and water. The structure of 1 was unambiguously determined by X-ray diffraction of its single crystal. Due to the coordination capability of the functional groups on fullerene, compound 1 was used as a buffer layer to modify ZnO in inverted polymer solar cells. The power conversion efficiency was improved from 3.65% to 4.18% for inverted P3HT:PC61BM solar cells.

  3. Bis(N-benzyl-N-methyldithiocarbamato-κ2S,S′(pyridine-κNcadmium(II

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Ehsan

    2016-01-01

    Full Text Available The title compound, [Cd(C9H10NS22(C5H5N], features a five-coordinate CdII atom, being coordinated by two nearly symmetrically chelating dithiocarbamate ligands and a pyridine N atom. The resulting NS4 donor set defines a distorted coordination geometry tending toward square pyramidal. In the molecular packing, centrosymmetric ten-membered {...HCNCS}2 synthons arise as a result of methylene-C—H...S interactions. These are connected into layers parallel to (10-2 via weak methyl-C—H...π(phenyl interactions.

  4. (E-N′-[3-(4-Chlorobenzoyloxybenzylidene]pyridine-4-carbohydrazide acetic acid monosolvate monohydrate

    Directory of Open Access Journals (Sweden)

    Zhi Fan

    2012-05-01

    Full Text Available In the Schiff base molecule of the title compound, C20H14ClN3O3·CH3COOH·H2O, the central benzene ring makes dihedral angles of 36.26 (7 and 27.59 (8°, respectively, with the terminal chlorophenyl and pyridine rings. In the crystal, the three components are linked by O—H...O, N—H...O, O—H...N and C—H...O hydrogen bonds into a double-tape structure along the a axis.

  5. Synthesis, Characterization, and Antimicrobial Activity Studies of Ni(II Complex with Pyridine as a Ligand

    Directory of Open Access Journals (Sweden)

    Faridul Islam

    2015-01-01

    Full Text Available We represent a metal complex which has been synthesized by the simple reaction with Ni(II chloride and pyridine (as a lignd affording a complex having the molecular formula [NiC5H5N2Cl2], characterized on the basis of elemental analyses, electronic, infrared, 1H NMR, 13C NMR spectra, magnetic susceptibility, and also aid of molar conductivity measurement. Conductivity measurement reveals nonelectrolytic nature of the complex. IR and 13C NMR spectra reveal the presence of cis- and trans-structure. On the basis of above analyses the square planar cis- and trans-structures are proposed for the prepared complex.

  6. 5-Bromo-N3-[(E-(6-bromopyridin-2-ylmethylidene]pyridine-3,4-diamine

    Directory of Open Access Journals (Sweden)

    Mingjian Cai

    2011-12-01

    Full Text Available The title compound, C11H8Br2N4, is a Schiff base obtained from 6-bromopicolinaldehyde and 5-bromopyridine-3,4-diamine. The molecule has an E configuration about the C=N bond and the dihedral angle between the two pyridine rings is 14.02 (1°. The observed conformation is stabilised by an intramolecular N—H...N hydrogen bond. In the crystal, molecules are stacked along the b axis and are linked through N—H...N hydrogen bonds into chains along the c axis.

  7. Colorimetric and electrochemical Pb2+ detection by imine-bridged tetrathiafulvalene-pyridine derivatives

    Institute of Scientific and Technical Information of China (English)

    TUNG; ChenHo

    2009-01-01

    Imine-bridged TTF-π-pyridine derivatives, 2NTTF, 3NTTF and 4NTTF, were synthesized and the cation-binding study was performed. It is noted that with the addition of the micromolar concentration of Pb2+ to the solution, these compounds display remarkable changes in solution color, 1H NMR spectra and electrochemical properties. The nitrogen atom of the imine-bridge in 2NTTF not only serves as a π-conjugated spacer but also participates in the sensing and coordinating properties.

  8. PROPERTIES OF DILUTE SOLUTIONS OF HYDROPHOBICALLY MODIFIED POLY(4-VINYL PYRIDINE) (POLYSOAPS)

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Hydrophobically modified poly(4-vinyl pyridines) by alkyl bromides are kinds of polysoap similar to the surfactant. Properties of dilute solutions were studied through the viscosity measurements in pure water and NaCl solutions. In aqueous solutions of polysoaps hydrophobic interaction can be attributed to aggregation of hydrophobic groups of the polysoap main chains. The hydrophobic groups of polysoap can aggregate to form hydrophobic microdomains (micelles) in aqueous solution. This is a compact conformation. The formation of such microdomains is a process of dynamic equilibrium.

  9. Structure, luminescence and antimicrobial properties of mononuclear silver(I) complexes of pyridine 2-carboxamide

    Indian Academy of Sciences (India)

    Sutapa Joardar; Shounak Roy; Suvendu Samanta; Amit Kumar Dutta

    2015-10-01

    Two Ag(I) complexes, [Ag(HL)2]ClO4 (1) and [Ag(HL)2]NO3·H2O (2), where HL is pyridine 2– carboxamide, have been synthesized and characterized by various spectroscopic techniques. The X-ray crystal structural analyses indicate that both the complexes consist of slightly distorted square planar silver(I) ions and ligand-supported weak Ag⋯Ag metallophilic interactions. Both the complexes show photoluminescence in solid state and acetonitrile solution at room temperature. Antimicrobial studies have been performed with these silver(I) complexes against various gram +ve, gram −ve bacterial and fungal species.

  10. (E-3-[5-(Diphenylaminothiophen-2-yl]-1-(pyridin-3-ylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Rui Li

    2013-09-01

    Full Text Available In the title compound, C24H18N2OS, the pyridine and the two phenyl rings are oriented at dihedral angles of 10.1 (5, 71.7 (6 and 68.7 (5°, respectively, to the central thiophene ring. In the crystal, pairs of weak C—H...O hydrogen bonds link inversion-related molecules, forming dimers. The dimers are linked by further weak C—H...O hydrogen bonds, forming chains running along the a-axis direction.

  11. Pyridine hydroxamic acids are specific anti-HCV agents affecting HDAC6.

    Science.gov (United States)

    Kozlov, Maxim V; Kleymenova, Alla A; Romanova, Lyudmila I; Konduktorov, Konstantin A; Kamarova, Kamila A; Smirnova, Olga A; Prassolov, Vladimir S; Kochetkov, Sergey N

    2015-06-01

    Recently we reported benzohydroxamic acids (BHAs) as potent and selective inhibitors of hepatitis C virus (HCV) replicon propagation. In this work 12 pyridine hydroxamic acids (PHAs) were synthesized and tested in full-genome replicon assay. It was found that PHAs possessed very similar anti-HCV properties compared to BHAs. Both classes of hydroxamic acids caused hyperacetylation of α-tubulin pointing to inhibition of histone deacetylase 6 (HDAC6) as part of their antiviral activity. The tested compounds did not inhibit the growth of poliovirus, displaying high selectivity against HCV.

  12. Bis[μ-N-(pyridin-2-ylmethylpyridin-2-amine-κ2N:N′]disilver(I bis(trifluoromethanesulfonate

    Directory of Open Access Journals (Sweden)

    Suk-Hee Moon

    2011-12-01

    Full Text Available In the binuclear title compound, [Ag2(C11H11N32](CF3O3S2, the complex cation is centrosymmetric, with the unique Ag+ cation coordinated by two pyridine N atoms from two symmetry-related N-(pyridin-2-ylmethylpyridin-2-amine ligands in a geometry slightly distorted from linear [N—Ag—N 161.02 (7°]. This set-up leads to the formation of a 14-membered cyclic dimer. The two pyridine rings coordinated to the Ag+ cation are tilted by 80.19 (7° with respect to each other. Intermolecular N—H...O hydrogen-bonding interactions between the cyclic dimer and the anion exist. A two-dimensional network parallel to the ac plane is constructed by three weak Ag...(O,N interactions as well as an F...F contact of 2.890 (4 Å.

  13. Analysis of denitrifier community in a bioaugmented sequencing batch reactor for the treatment of coking wastewater containing pyridine and quinoline

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yaohui; Xing, Rui; Wen, Donghui; Tang, Xiaoyan [Peking Univ., Beijing (CN). Key Lab. of Water and Sediment Sciences (Ministry of Education); Sun, Qinghua [Peking Univ., Beijing (CN). Key Lab. of Water and Sediment Sciences (Ministry of Education); Chinese Center for Disease Control and Prevention, Beijing (China). Inst. of Environmental Health and Related Product Safety

    2011-05-15

    The denitrifier community and associated nitrate and nitrite reduction in the bioaugmented and general sequencing batch reactors (SBRs) during the treatment of coking wastewater containing pyridine and quinoline were investigated. The efficiency and stability of nitrate and nitrite reduction in SBR was considerably improved after inoculation with four pyridine- or quinoline-degrading bacterial strains (including three denitrifying strains). Terminal restriction fragment length polymorphism (T-RFLP) based on the nosZ gene revealed that the structures of the denitrifier communities in bioaugmented and non-bioaugmented reactors were distinct and varied during the course of the experiment. Bioaugmentation protected indigenous denitrifiers from disruptions caused by pyridine and quinoline. Clone library analysis showed that one of the added denitrifiers comprised approximately 6% of the denitrifier population in the bioaugmented sludge. (orig.)

  14. Synthesis of Some New Pyridine-2,6-carboxamide-derived Schiff Bases as Potential Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Abd El-Galil E. Amr

    2010-07-01

    Full Text Available A series of pyridine-bridged 2,6-bis-carboxamide Schiff's bases has been prepared starting from 2,6-pyridinedicarbonyl dichloride (1 and L-alanine or 2-methyl-alanine methyl ester.The coupling of acid chloride 1 with L-alanine methyl ester hydrochloride -or 2-methylalanine methyl ester hydrochloride gave the corresponding 2,6-bis-carboxamide pyridine methyl esters 2a,b.Hydrazonolysis of 2 with hydrazine hydrate afforded the corresponding bis-hydrazides 3a,b. Treatment of 3a,b with appropriate aromatic or heterocyclic aldehydes afforded the corresponding pyridine- bridged 2,6-bis-carboxamide Schiff's bases 4a-f and 5a-f, respectively. The newly synthesized compounds 2-5 were screened for their bactericidal and fungicidal activities. Many of the obtained compounds exhibited significant antimicrobial activity, comparable to streptomycin and fusidic acid, which were used as reference antibiotic drugs.

  15. Bis[μ-N,N'-bis(quinolin-8-yl)pyridine-2,6-dicarboxamido]dizinc(II) dichloromethane disolvate.

    Science.gov (United States)

    Xu, Hui-Hua; Tao, Xian; Li, Yue-Qin; Shen, Ying-Zhong; Wei, Yan-Hong

    2011-04-01

    The title compound, [Zn(2)(C(25)H(15)N(5)O(2))(2)]·2CH(2)Cl(2), is a dinuclear double-helical complex which lies on a crystallographic twofold axis. In the complex, both ligands are partitioned into two tridentate domains which allow each ligand to bridge both metal centres. Each Zn(II) atom is six-coordinated in a distorted octahedral environment formed by two amide N atoms, two quinoline N atoms and two pyridine N atoms from two different ligand molecules, with the central pyridine ring, unusually, bridging two Zn(II) atoms. The deprotonated ligand is not planar, the amide side chains being considerably twisted out from the plane of the central pyridine ring.

  16. Carbon dioxide is tightly bound in the [Co(Pyridine)(CO{sub 2})]{sup −} anionic complex

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Jacob D.; Buytendyk, Allyson M.; Zhang, Xinxing; Bowen, Kit H., E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kim, Seong K. [Department of Chemistry, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2015-11-14

    The [Co(Pyridine)(CO{sub 2})]{sup −} anionic complex was studied through the combination of photoelectron spectroscopy and density functional theory calculations. This complex was envisioned as a primitive model system for studying CO{sub 2} binding to negatively charged sites in metal organic frameworks. The vertical detachment energy (VDE) measured via the photoelectron spectrum is 2.7 eV. Our calculations imply a structure for [Co(Pyridine)(CO{sub 2})]{sup −} in which a central cobalt atom is bound to pyridine and CO{sub 2} moieties on either sides. This structure was validated by acceptable agreement between the calculated and measured VDE values. Based on our calculations, we found CO{sub 2} to be bound within the anionic complex by 1.4 eV.

  17. One-pot synthesis of 2-phenylimidazo[1,2-α]pyridines from acetophenone, [Bmim]Br(3) and 2-aminopyridine under solvent-free conditions.

    Science.gov (United States)

    Le, Zhang-Gao; Xie, Zong-Bo; Xu, Jian-Ping

    2012-11-09

    One-pot synthesis of 2-phenylimidazo[1,2-α]pyridines from acetophenone, [Bmim]Br(3) and 2-aminopyridine under solvent-free conditions in the presence of Na(2)CO(3), gave the corresponding 2-phenylimidazo[1,2-α]pyridines in excellent yields ranging from 72% to 89%.

  18. Carbon-Oxygen Bond Cleavage by Bis(imino)pyridine Iron Compounds : Catalyst Deactivation Pathways and Observation of Acyl C-O Bond Cleavage in Esters

    NARCIS (Netherlands)

    Trovitch, Ryan J.; Lobkovsky, Emil; Bouwkamp, Marco W.; Chirik, Paul J.

    2008-01-01

    Investigations into the substrate scope of bis(imino)pyridine iron-catalyzed hydrogenation and [2 pi + 2 pi]. diene cyclization reactions identified C-O bond cleavage as a principal deactivation pathway. Addition of diallyl or allyl ethyl ether to the bis(imino)pyridine iron dinitrogen complex, ((iP

  19. Etude de la dynamique des porteurs dans des nanofils de silicium par spectroscopie terahertz

    Science.gov (United States)

    Beaudoin, Alexandre

    Ce memoire presente une etude des proprietes de conduction electrique et de la dynamique temporelle des porteurs de charges dans des nanofils de silicium sondes par rayonnement terahertz. Les cas de nanofils de silicium non intentionnellement dopes et dopes type n sont compares pour differentes configurations du montage experimental. Les mesures de spectroscopie terahertz en transmission montre qu'il est possible de detecter la presence de dopants dans les nanofils via leur absorption du rayonnement terahertz (˜ 1--12 meV). Les difficultes de modelisation de la transmission d'une impulsion electromagnetique dans un systeme de nanofils sont egalement discutees. La detection differentielle, une modification au systeme de spectroscopie terahertz, est testee et ses performances sont comparees au montage de caracterisation standard. Les instructions et des recommendations pour la mise en place de ce type de mesure sont incluses. Les resultats d'une experience de pompe optique-sonde terahertz sont egalement presentes. Dans cette experience, les porteurs de charge temporairement crees suite a l'absorption de la pompe optique (lambda ˜ 800 nm) dans les nanofils (les photoporteurs) s'ajoutent aux porteurs initialement presents et augmentent done l'absorption du rayonnement terahertz. Premierement, l'anisotropie de l'absorption terahertz et de la pompe optique par les nanofils est demontree. Deuxiemement, le temps de recombinaison des photoporteurs est etudie en fonction du nombre de photoporteurs injectes. Une hypothese expliquant les comportements observes pour les nanofils non-dopes et dopes-n est presentee. Troisiemement, la photoconductivite est extraite pour les nanofils non-dopes et dopes-n sur une plage de 0.5 a 2 THz. Un lissage sur la photoconductivite permet d'estimer le nombre de dopants dans les nanofils dopes-n. Mots-cles: nanofil, silicium, terahertz, conductivite, spectroscopie, photoconductivite.

  20. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    Science.gov (United States)

    Bendaoud, Adlane Larbi

    Les evaporateurs de refrigeration sont surtout du type tube a ailettes, appeles serpentins, et fonctionnent dans l'une des conditions suivantes: seche, humide ou avec formation de givre. Il a ete demontre que la formation du givre sur la paroi exterieure de l'echangeur engendre une surconsommation energetique a cause des operations de degivrage puisque 15 a 20% seulement de la chaleur produite sert au degivrage tandis que le reste est dissipee dans l'environnement [1]. Avec l'avenement des nouveaux refrigerants, moins nocifs envers l'environnement, l'industrie du froid se trouve penalisee du fait que peu ou pas de composantes mecaniques (compresseur, pompe, echangeur...etc.) adaptees sont disponibles [3]. Il s'agit pour la communaute des frigoristes de combler ce retard technologique en redeveloppant ces composantes mecaniques afin qu'elles soient adaptees aux nouveaux refrigerants. Dans cette optique, et afin de mieux comprendre le comportement thermique des evaporateurs au CO2 fonctionnant dans des conditions seches, qu'un groupe de chercheurs du CanmetENERGIE avaient lance, en 2000, un programme de R & D. Dans le cadre de programme un outil de simulation des evaporateurs au CO2 a ete developpe et un banc d'essai contenant une boucle secondaire de refrigeration utilisant le CO2 comme refrigerant a ete construit. Comme continuite de ce travail de recherche, en 2006 ce meme groupe de recherche a lance un nouveau projet qui consiste a faire une etude theorique et experimentale des evaporateurs au CO2 operants dans des conditions de givrage. Et, c'est exactement dans le cadre de ce projet que se positionne ce travail de these. Ce travail de recherche a ete entrepris pour mieux comprendre le comportement thermique et hydrodynamique des serpentins fonctionnant dans des conditions de givrage, l'effet des circuits de refrigerant ainsi que celui des parametres geometriques et d'operation. Pour cela, un travail theorique supporte par une etude experimentale a ete effectue

  1. How to minimize toxic exposure to pyridine during continuous infusion of ceftazidime in patients with cystic fibrosis?

    Science.gov (United States)

    Bourget, P; Amin, A; Dupont, C; Abely, M; Desmazes-Dufeu, N; Dubus, J C; Jouani, B-L; Merlette, C; Nové-Josserand, R; Pages, J; Panzo, R; Vidal, F; Voge, F; Hubert, D

    2014-05-01

    Ceftazidime is particularly efficient against Pseudomonas aeruginosa in cystic fibrosis patients. Thus, the spontaneous production of pyridine, which is a toxic product, raises some concern. Our aim was to examine the kinetics of degradation of ceftazidime in portable infusion pumps either at 4°C, 22°C, or 33°C and to propose some recommendations in order to reduce the pyridine exposure. Two administration models were studied in vitro. In model 1, we administered 12 g of ceftazidime infused over 23 h (once-daily infusion) compared to 6 g infused over 11.5 h in model 2 (twice-daily regimen). Samples were collected at 0 h and then every 4 and 2 h after the shaping of portable infusion pumps in models 1 and 2, respectively. Both ceftazidime and pyridine were analyzed using an ultraviolet high-performance liquid chromatograph. Production of pyridine is highly depending on the temperature. The in situ production of pyridine per day of treatment decreases at a ratio close to 1/6 and 1/3 between 33°C and 4°C in models 1 and 2, respectively. Regardless of the conditions, the production of pyridine is significantly lower in model 2, whereas the total delivery amount of ceftazidime is significantly higher at 4°C and 33°C compared to that in model 1. According to a the precautionary principle, these findings lead to three major recommendations: (i) exposing a solution of ceftazidime to over 22°C should be strictly avoided, (ii) a divided dose of 6 g over 11.5 h instead of a once-daily administration is preferred, and (iii) infusion should be administered immediately after reconstitution.

  2. Mechanism of the 6-hydroxy-3-succinoyl-pyridine 3-monooxygenase flavoprotein from Pseudomonas putida S16.

    Science.gov (United States)

    Yu, Hao; Hausinger, Robert P; Tang, Hong-Zhi; Xu, Ping

    2014-10-17

    6-Hydroxy-3-succinoyl-pyridine (HSP) 3-monooxygenase (HspB), a flavoprotein essential to the pyrrolidine pathway of nicotine degradation, catalyzes pyridine-ring β-hydroxylation, resulting in carbon-carbon cleavage and production of 2,5-dihydroxypyridine. Here, we generated His6-tagged HspB in Escherichia coli, characterized the properties of the recombinant enzyme, and investigated its mechanism of catalysis. In contrast to conclusions reported previously, the second product of the HspB reaction was shown to be succinate, with isotope labeling experiments providing direct evidence that the newly introduced oxygen atom of succinate is derived from H2O. Phylogenetic analysis reveals that HspB is the most closely related to two p-nitrophenol 4-monooxygenases, and the experimental results exhibit that p-nitrophenol is a substrate of HspB. The reduction of HspB (with maxima at 375 and 460 nm, and a shoulder at 485 nm) by NADH was followed by stopped-flow spectroscopy, and the rate constant for reduction was shown to be stimulated by HSP. Reduced HspB reacts with oxygen to form a C(4a)-(hydro)peroxyflavin intermediate with an absorbance maximum at ∼400 nm within the first few milliseconds before converting to the oxidized flavoenzyme species. The formed C(4a)-hydroperoxyflavin intermediate reacts with HSP to form an intermediate that hydrolyzes to the products 2,5-dihydroxypyridine and succinate. The investigation on the catalytic mechanism of a flavoprotein pyridine-ring β-position hydroxylase provides useful information for the biosynthesis of pyridine derivatives.

  3. Chemical Coupling SERS Properties of Pyridine on Silver-Caged Metal Clusters M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+)

    Science.gov (United States)

    Chen, Lei; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-Qin

    2017-07-01

    Using density functional theory, this work presents a comprehensive analysis of nonresonant surface-enhanced Raman scattering enhancement of pyridine on M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+). Computational results indicate that the chemical enhancement of pyridine on M@Ag12 is closely associated with the charge properties of silver-caged clusters. Pyridine on negative clusters exhibits the strongest chemical enhancement with a factor of about 103, while the chemical enhancement is only about 102 for pyridine on neutral clusters and 10 for pyridine on positive clusters. The polarizability analyses elucidate the nature of the chemical enhancement that delocalized electrons of negative adsorption systems occupy higher molecular orbitals than those of neutral and positive adsorption systems, which can lead to stronger nonresonant chemical enhancement.

  4. Synthesis and cytotoxicity of thieno[2,3-b]quinoline-2-carboxamide and cycloalkyl[b]thieno[3,2-e]pyridine-2-carboxamide derivatives.

    Science.gov (United States)

    Leung, Euphemia; Pilkington, Lisa I; van Rensburg, Michelle; Jeon, Chae Yeon; Song, Mirae; Arabshahi, Homayon J; De Zoysa, Gayan Heruka; Sarojini, Vijayalekshmi; Denny, William A; Reynisson, Jóhannes; Barker, David

    2016-03-01

    Seventy nine derivatives of thieno[2,3-b]quinolines, tetrahydrothieno[2,3-b]quinoline, dihydrocyclopenta[b]thieno[3,2-e]pyridine, cyclohepta[b]thieno[3,2-e]pyridine and hexahydrocycloocta[b]thieno[3,2-e]pyridine were either synthesized or obtained commercially and tested for their antiproliferative activity against HCT116, MDA-MB-468 and MDA-MB-231 human cancer cell lines. The most potent eight compounds were active against all cell lines with IC50 values in the 80-250nM range. In general hexahydrocycloocta[b]thieno[3,2-e]pyridines were most active with increasing activity observed as larger cycloalkyl rings were fused to the pyridine ring.

  5. Chemical Coupling SERS Properties of Pyridine on Silver-Caged Metal Clusters M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+)

    Science.gov (United States)

    Chen, Lei; Wang, Zhigang; Li, Zhengqiang; Zhang, Rui-Qin

    2016-10-01

    Using density functional theory, this work presents a comprehensive analysis of nonresonant surface-enhanced Raman scattering enhancement of pyridine on M@Ag12 (M = V-, Nb-, Ta-, Cr, Mo, W, Mn+, Tc+, Re+). Computational results indicate that the chemical enhancement of pyridine on M@Ag12 is closely associated with the charge properties of silver-caged clusters. Pyridine on negative clusters exhibits the strongest chemical enhancement with a factor of about 103, while the chemical enhancement is only about 102 for pyridine on neutral clusters and 10 for pyridine on positive clusters. The polarizability analyses elucidate the nature of the chemical enhancement that delocalized electrons of negative adsorption systems occupy higher molecular orbitals than those of neutral and positive adsorption systems, which can lead to stronger nonresonant chemical enhancement.

  6. One-pot synthesis of tetracyclic fused imidazo[1,2-a]pyridines via a three-component reaction

    Science.gov (United States)

    Yang, Bo; Tao, Chuanye; Shao, Taofeng

    2016-01-01

    Summary A novel three-component reaction has been developed to assemble biologically and pharmaceutically important tetracyclic fused imidazo[1,2-a]pyridines in a one-pot fashion utilizing readily available 2-aminopyridines, isatins and isocyanides. The three-component coupling proceeds through the Groebke–Blackburn–Bienaymé reaction followed by a retro-aza-ene reaction and subsequent nucleophilic reaction of the in-situ generated imidazo[1,2-a]pyridines bearing an isocyanate functional group. PMID:27559401

  7. cis-Bis(4-methylpiperazine-1-carbodithioato-κ2S,S′bis(pyridine-κNcadmium

    Directory of Open Access Journals (Sweden)

    P. Valarmathi

    2012-01-01

    Full Text Available In the title complex, [Cd(C6H11N2S22(C5H5N2], the CdII ion is hexacoordinated by two N atoms from two pyridine ligands and by four S atoms from two dithiocarbamate ligands in a distorted octahedral geometry. The CdII ion lies on a twofold axis. The piperazine ring is in chair conformation and its least-squares plane makes a dihedral angle of 81.4 (1° with that of the pyridine ring.

  8. Identification of Intermediates in Pyridine Pyrolysis with Molecular-beam Mass Spectrometry and Tunable Synchrotron VUV Photoionization

    Institute of Scientific and Technical Information of China (English)

    Xin Hong; Taichang Zhang; Lidong Zhang; Fei Qi

    2009-01-01

    The pyrolysis of pyridine (5.26% pyridine in argon) was performed with tunable synchrotron vacuum ultraviolet photoionization and molecular-beam mass spectrometry technique at the temperature range of 1255-1765 K at 267 Pa. About 20 products and intermediates, containing major species H2, HCN, C2H2, C5H3N, C4H2, and C3H3N, were identified by near-threshold measurements of photoionization mass spectra and their mole fractions vs.temperatures were estimated. The major reaction pathways are analyzed based on the experimental observations.

  9. Proton-coupled electron transfer in [pyridine·(H2O)n]-, n = 3, 4, clusters

    Science.gov (United States)

    Archer, Kaye A.; Jordan, Kenneth D.

    2016-09-01

    The equation-of-motion method is used to map out one-dimensional potentials for proton-coupled electron transfer in the [pyridine·(H2O)n]-, n = 3, 4, clusters. In both cases there is an avoided crossing between valence-type pyridinyl·(OH-) (H2O)n-1 and dipole-bound pyridine·(H2O)n- anion species. For the n = 3 cluster, the mixing is sufficiently strong that both limiting structures are predicted to be sampled in the vibrational zero-point level.

  10. Dimethyl and diethyl esters of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid: a comparison.

    Science.gov (United States)

    Alfonso, Montserrat; Stoeckli-Evans, Helen

    2016-02-01

    In dimethyl 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ate, C18H14N4O4, (I), and diethyl 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ate, C20H18N4O4, (II), the dimethyl and diethyl esters of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid, the orientation of the two pyridine rings differ. In (I), pyridine ring B is inclined to pyrazine ring A by 44.8 (2)° and the pyridine and pyrazine N atoms are trans to one another, while pyridine ring C is inclined to the pyrazine ring by 50.3 (2)°, with the pyridine and pyrazine N atoms cis to one another. In compound (II), the diethyl ester, which possesses twofold rotation symmetry, the pyridine ring is inclined to the pyrazine ring by 40.7 (1)°, with the pyridine and pyrazine N atoms trans to one another. In the crystal of (I), mol-ecules are linked by C-H⋯N hydrogen bonds, forming chains along [001]. The chains are linked by C-H⋯π inter-actions, forming a three-dimensional structure. In the crystal of (II), mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional framework. There are C-H⋯π inter-actions present within the framework.

  11. Structure and Luminescence Property of a Hexanuclear Silver(I) Cluster Containing Pyridine-3-carboxaldehyde Thiosemicarbazone

    Institute of Scientific and Technical Information of China (English)

    SUN Qiao-Zhen; CHAI Li-Yuan

    2012-01-01

    A new hexanuclear silver(I) compound containing thiosemicarbazone with group of 3-pyridine was synthesized and structurally characterized by single-crystal X-ray diffraction,elemental analysis and fluorescence spectrum.The title compound 3 crystallizes in monoclinic,space group C2/m with a = 18.6523(9),b = 24.7519(11),c = 22.4542(15) ,β = 93.4960(10)°,V = 10347.4(10)3,C68H104Ag6N30O8S6,Mr = 2309.39,Dc = 1.482g/cm3,μ(MoKα) = 1.293 mm-1,F(000) = 4656,Z = 4,the final R = 0.0544 and wR = 0.1580 for 6733 observed reflections(I 〉 2σ(I)).In the structure,two Ag6L36(L3 = pyridine-3-carboxaldehyde thiosemicarbazone) clusters are contained.In each cluster,the S atom of ligand L3 served as a triply bridged chelator to connect the six silver atoms into a Ag6L36 cluster.Luminescence investigation revealed that the band at 630 nm was attributed to cluster-centered(CC) electron transfer,and those at 493 and 530 nm to the LMCT and CC transitions,respectively.

  12. Dithiafulvene-based organic sensitizers using pyridine as the acceptor for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Jun; Cao, Yaxiong; Liang, Xiaozhong; Zheng, Jingxia; Zhang, Fang [Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Wei, Shuxian; Lu, Xiaoqing [College of Science, China University of Petroleum, Qingdao, Shandong 266555 (China); Guo, Kunpeng, E-mail: guokunpeng@tyut.edu.cn [Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Yang, Shihe, E-mail: chsyang@ust.hk [Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2017-05-01

    Three dithiafulvene-based metal-free organic sensitizers all using pyridine as the acceptor but with different π-bridges of phenyl (DTF-Py1), thienyl (DTF-Py2) and phenyl-thienyl (DTF-Py3) have been designed, synthesized and used as photosensitizers for dye-sensitized solar cells (DSCs). Introducing thienyl unit into the π-bridge, as well as extension of the π-bridge can dramatically improve their light harvesting ability and suppress the electron recombination, thus uplifting the performance of DSCs. The overall power conversion efficiency of DSC based on DTF-Py3 shows the highest efficiency of 2.61% with a short-circuit photocurrent density of 7.99 mA cm{sup -2}, an open-circuit photovoltage of 630 mV, and a fill factor of 0.52, under standard global AM 1.5 solar light condition. More importantly, the long-term stability of the DTF-Py3 based DSCs under 500 h light-soaking has been demonstrated. - Highlights: • Dithiafulvene sensitizers using pyridine ring as the acceptor were synthesized for the first time. • The power conversion efficiency of 2.61% was obtained for DTF-Py3 sensitized cell. • DTF-Py3 loaded TiO{sub 2} film shows improved light harvesting ability and suppressed electron recombination.

  13. Gold-catalyzed Synthesis of Pyridine Containing Macrocycles, Related to Porphyrin

    Institute of Scientific and Technical Information of China (English)

    DYKER,Gerald; LIU,Jian-Hui; MERZ,Klaus

    2004-01-01

    @@ Porphyrins are very important substances used in a wide range of model systems in many areas, such as biomimic chemistry and material science. This kind of macrocycle generally consists of 5-membered ring to form a cyclic extended aromatic network. Recently much work have been done concerning the modification of porphyrins core structures, and many kinds of analogues have been recorded. One of the important aspects was the research of the porphyrinogen ligand.These macrocycles bear functional resemblance to certain kind of polydentate ligand, and provide a variety of tri-dimensional binding cavities for metal ions. In addition, some other kinds of analogues have been recorded, involving the introduction of a CH unit to replace one of the nitrogen atoms. We also notice the fact that pyridine is a very effective ligand, and it can coordinate with many kinds of metals. Based on these observations, we would like to design and synthesize a new porphyrinogen (5) analogue containing a NNNN core, two of the N atoms from pyrrole and the other two N from pyridine. Such core modifications may alter the electronic structure of the ring and provide variable cavity for metal coordination.

  14. Aerobic granulation strategy for bioaugmentation of a sequencing batch reactor (SBR) treating high strength pyridine wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaodong; Chen, Yan [Jiangsu Key Laboratory for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province (China); Zhang, Xin [Jiangsu Key Laboratory for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province (China); Suzhou Institute of Architectural Design Co., Ltd, Suzhou 215021, Jiangsu Province (China); Jiang, Xinbai; Wu, Shijing [Jiangsu Key Laboratory for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province (China); Shen, Jinyou, E-mail: shenjinyou@mail.njust.edu.cn [Jiangsu Key Laboratory for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province (China); Sun, Xiuyun; Li, Jiansheng; Lu, Lude [Jiangsu Key Laboratory for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province (China); Wang, Lianjun, E-mail: wanglj@mail.njust.edu.cn [Jiangsu Key Laboratory for Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province (China)

    2015-09-15

    Abstract: Aerobic granules were successfully cultivated in a sequencing batch reactor (SBR), using a single bacterial strain Rhizobium sp. NJUST18 as the inoculum. NJUST18 presented as both a good pyridine degrader and an efficient autoaggregator. Stable granules with diameter of 0.5–1 mm, sludge volume index of 25.6 ± 3.6 mL g{sup −1} and settling velocity of 37.2 ± 2.7 m h{sup −1}, were formed in SBR following 120-day cultivation. These granules exhibited excellent pyridine degradation performance, with maximum volumetric degradation rate (V{sub max}) varied between 1164.5 mg L{sup −1} h{sup −1} and 1867.4 mg L{sup −1} h{sup −1}. High-throughput sequencing analysis exhibited a large shift in microbial community structure, since the SBR was operated under open condition. Paracoccus and Comamonas were found to be the most predominant species in the aerobic granule system after the system had stabilized. The initially inoculated Rhizobium sp. lost its dominance during aerobic granulation. However, the inoculation of Rhizobium sp. played a key role in the start-up process of this bioaugmentation system. This study demonstrated that, in addition to the hydraulic selection pressure during settling and effluent discharge, the selection of aggregating bacterial inocula is equally important for the formation of the aerobic granule.

  15. N,N′-Bis(pyridin-2-ylbenzene-1,4-diamine–quinoxaline (2/1

    Directory of Open Access Journals (Sweden)

    Barbara Wicher

    2011-12-01

    Full Text Available The asymmetric unit of the title compound, 2C16H14N4·C8H6N2, consits of one molecule of N,N′-bis(pyridin-2-ylbenzene-1,4-diamine (PDAB and one half-molecule of quinoxaline (QX that is located around an inversion centre and disordered over two overlapping positions. The PDAB molecule adopts a non-planar conformation with an E configuration at the two partially double exo C...;N bonds of the 2-pyridylamine units. In the crystal, these self-complementary units are N—H...N hydrogen bonded via a cyclic R22(8 motif, creating tapes of PDAB molecules extending along [010]. Inversion-related tapes are arranged into pairs through π–π stacking interactions between the benzene rings [centroid–centroid distance = 3.818 (1 Å] and the two symmetry-independent pyridine groups [centroid–centroid distance = 3.760 (1 Å]. The QX molecules are enclosed in a cavity formed between six PDAB tapes.

  16. CONDUCTING BLENDS OF POLY(2-VINYL PYRIDINE) AND POLYETHYLENE OXIDE WITH HIGH MOLECULAR WEIGHT

    Institute of Scientific and Technical Information of China (English)

    CUI Minhui; GUO Junshi; XIE Hongquan; CHENG Donghua

    1997-01-01

    Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinyl pyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after doped with LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQ concentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied.The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content.At a Li/ethylene oxide molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5,the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5. Scanning electron microscopy (SEM) on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry (DSC) results show that LiClO4 could act as a compatibilizer in the blend.

  17. Role of Pyridinic-N for Nitrogen-doped graphene quantum dots in oxygen reaction reduction.

    Science.gov (United States)

    Sun, Lang; Luo, Yi; Li, Ming; Hu, Guanghui; Xu, Yongjie; Tang, Tao; Wen, Jianfeng; Li, Xinyu; Wang, Liang

    2017-12-15

    Nitrogen-doped graphene quantum dots (N-GQDs) exhibit exciting properties in the oxygen reduction reaction (ORR) for ample electrocatalytic edging and N-doped active sites. However, low yield and high dispersity of N-GQDs prohibit their direct application as the electrocatalyst. In this paper, two facile hydrothermal progress were developed to synthesize the high-yield N-GQDs with the diameter of ca. 2-6nm and the hybrid of N-GQDs/Reduced Graphene Oxide (N-GQDs/r-GO). The results demonstrated that the N-GQDs/r-GO display remarkable electrocatalytic activity. Moreover, it can be found that the pyridinic-N plays a major role in ORR. Both the average electron transfer number and the onset potential depend on the content of pyridinic-N. The proposed synthesis strategy is facile and low-cost, serving as a feasible method for the development of highly efficient electrocatalysts. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The co-occurrence of two pyridine alkaloids, mimosine and trigonelline, in Leucaena leucocephala.

    Science.gov (United States)

    Ogita, Shinjiro; Kato, Misako; Watanabe, Shin; Ashihara, Hiroshi

    2014-01-01

    Leucaena leucocephala is a nitrogen-fixing tropical leguminous tree that produces two pyridine alkaloids, i. e. mimosine [beta-(3-hydroxy-4-pyridon-1-yl)-L-alanine] and trigonelline (1-methylpyridinium-3-carboxylate). Mimosine has been detected in leaves, flowers, pods, seeds, and roots, and it is one of the principal non-protein amino acids that occurs in all organs. Asparagine was the most abundant amino acid in flowers. The mimosine content varied from 3.3 micromol/g fresh weight (FW) in developing flowers to 171 micromol/g FW in mature seeds. Trigonelline was also detected in leaves, flowers, pods, and seeds, but not roots. The trigonelline content was lower than that of mimosine in all organs. It varied from 0.12 micromol/g FW in developing seeds to 2.6 micromol/g FW in mature seeds. [2-14C]Nicotinic acid supplied to the developing seeds was incorporated into trigonelline but not mimosine. This indicates that the pyridine and dihydroxypyridine structures of these two alkaloids are derived from distinct precursors. The physiological functions of mimosine and trigonelline are discussed briefly.

  19. Organometallic mediated radical polymerization of vinyl acetate using bis(imino)pyridine vanadium trichloride complexes.

    Science.gov (United States)

    Perry, Mitchell R; Allan, Laura E N; Decken, Andreas; Shaver, Michael P

    2013-07-07

    The synthesis and characterization of one novel proligand and six novel vanadium(III) trichloride complexes is described. The controlled radical polymerization activity towards vinyl acetate of these, and eight other bis(imino)pyridine vanadium trichloride complexes previously reported, is investigated. Those complexes possessing variation at the N-aryl para-position with no steric protection offered by ortho-substituents (4 examples) result in poor control over poly(vinyl acetate) polymerization. Control is improved with increasing steric bulk at the ortho-position of the N-aryl substituent (4 examples) although attempts to increase steric bulk past isopropyl were unsuccessful. Synthesizing bis(imino)pyridine vanadium trichloride complexes with substituted imine backbones restores polymerization control when aliphatic substituents are used (4 examples) but ceases to make any drastic improvements on catalyst lifetime. Modification of the polymerization conditions is also investigated, in an attempt to improve the catalyst lifetime. Expansion of the monomer scope to include other vinyl esters, particularly those derived from renewable resources, shows promising results.

  20. Proton Migration in Clusters Consisting of Protonated Pyridine Solvated by Water Molecules.

    Science.gov (United States)

    Berthias, Francis; Feketeová, Linda; Chermette, Henry; Forquet, Valérian; Morell, Christophe; Abdoul-Carime, Hassan; Farizon, Bernadette; Farizon, Michel; Märk, Tilmann D

    2015-10-26

    Proton transfer (PT) from protonated pyridine to water molecules is observed after excitation of microhydrated protonated pyridine (Py) clusters PyH(+) (H2 O)n (n=0-5) is induced by a single collision with an Ar atom at high incident velocity (95×10(3)  m s(-1) ). Besides the fragmentation channel associated with the evaporation of water molecules, the charged-fragment mass spectrum shows competition between the production of the PyH(+) ion (or its corresponding charged fragments) and the production of H(+) (H2 O) or H(+) (H2 O)2 ions. The increase in the production of protonated water fragments as a function of the number of H2 O molecules in the parent cluster ion as well sd the observation of a stable H(+) (H2 O)2 fragment, even in the case of the dissociation of PyH(+) (H2 O)2 , are evidence of the crucial role of PT in the relaxation process, even for a small number of solvating water molecules.

  1. Pyridine-2,6-diyl dinitroxides as room-temperature triplet ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hinako; Tonegawa, Asato; Ishida, Takayuki, E-mail: takayuki.ishida@uec.ac.jp [Department of Engineering Science, The University of Electro-Communications, Tokyo (Japan)

    2016-02-01

    We have proposed tert-butyl 2-pyridyl nitroxide radicals as a promising paramagnetic chelating ligand, where the direct radical-metal bond leads to strong magnetic interaction. We successfully synthesized and isolated PyBN derivatives (pyridine-2,6-diyl bis(tert-butyl nitroxides)). The molecular and crystal structures of the target biradicals, MesPyBN, AntPyBN and tBuOPyBN were determined from the X-ray crystal structure analysis, which possess mesityl, 9-anthryl and tert-butoxy groups at the 5-position of the pyridine ring, respectively. The ground triplet state was characterized by means of SQUID susceptometry for each compound. On heating, the χ{sub m}T values of all the PyBN derivatives increased and reached a plateau at ca. 1.0 cm{sup 3} K mol{sup −1} at 300 K. It implies that biradicals behaved as triplet molecules even at room temperature, or 2J/k{sub B} >> 300 K. From the decay monitored in solution electron-spin resonance spectroscopy, MesPyBN was the most persistent, while tBuOPyBN was the most reactive, of the three.

  2. Synthesis, characterization, and antioxidant properties of novel inulin derivatives with amino-pyridine group.

    Science.gov (United States)

    Hu, Yunxia; Zhang, Jun; Yu, Chunwei; Li, Qing; Dong, Fang; Wang, Gang; Guo, Zhanyong

    2014-09-01

    A series of novel inulin derivatives were synthesized via reaction of chloracetyl inulin (CAIL) with amino-pyridines, including 2-(2-amino-pyridyl)acetyl inulin chloride (2APAIL), 2-(3-amino-pyridyl)acetyl inulin chloride (3APAIL), 2-(4-amino-pyridyl)acetyl inulin chloride (4APAIL), 2-(2,3-diamino-pyridyl)acetyl inulin chloride (2,3DAPAIL), and 2-(3,4-diamino-pyridyl)acetyl inulin (3,4DAPAIL). The antioxidant property of the products and 2-pyridylacetyl inulin chloride (PAIL) against hydroxyl radicals (·OH), superoxide radicals (O2·), and DPPH radicals (DPPH·) were evaluated in vitro, respectively. Results showed that 4APAIL and 3,4DAPAIL exhibited remarkable improvement on scavenging ·OH and DPPH·, which can scavenge the radical of OH completely at 0.4 mg/mL. Besides, the scavenging activity of 2,3DAPAIL to O2· was excellent among all of the tested samples, reaching 85% at 1.6 mg/mL. These data indicate that all of the inulin derivatives have better antioxidant activities than inulin, and the scavenging effect indices are affected by the number and position of the amino group on pyridine grafted to the inulin derivatives.

  3. Development and validation of RP-HPLC method for simultaneous estimation of nimesulide, phenylephrine hydrochloride, chlorpheniramine maleate and caffeine anhydrous in pharmaceutical dosage form.

    Science.gov (United States)

    Kumar, Ashok; Sharma, Rishbha; Nair, Anroop; Saini, Gautam

    2012-01-01

    In this study, a simple, specific and accurate reverse phase high performance liquid chromatographic method was developed for the simultaneous determination of nimesulide (NS), phenylephrine hydrochloride (PE), chlorpheniramine maleate (CPM) and caffeine anhydrous (CF) in pharmaceutical dosage forms. A reversed phase Hypersil phenyl column (4.6 mm x 25 cm) with mobile phase having pH 5.5 consisting of methanol and buffer (55:45, v/v) was used. The flow rate was 1.0 mL per minute and the effluents were monitored at 214 nm. The retention times of all the drugs were found to be 7.47 min (NS), 3.944 min (PE), 4.55 min (CF) and 17.15 min (CPM), respectively. The linearity for all the drugs was obtained in the range of 300-800 microg/mL (NS), 15-32 microg/mL (PE), 16-32 microg/mL (CPM) and 30-180 microg/mL (CF), respectively. The results of analysis have been well validated according to guidelines of International Conference of Harmonisation of technical requirements for registration of pharmaceuticals for human use. The method was found to be simple, precise, economical, less time consuming and reproducible. Hence, the suggested procedure could be used for the determination of all the four drugs in commercial preparations.

  4. Pretreatment of Corn Stover by Low Moisture Anhydrous Ammonia (LMAA) in a Pilot-Scale Reactor and Bioconversion to Fuel Ethanol and Industrial Chemicals.

    Science.gov (United States)

    Nghiem, Nhuan P; Senske, Gerard E; Kim, Tae Hyun

    2016-04-01

    Corn stover (CS) adjusted to 50, 66, and 70 % moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70 % moisture CS was treated at 90 and 100 °C whereas the others were treated at 90 °C only. The 70 % moisture pretreated CS then was subjected to a storage study under non-sterile conditions for 3 months. It was found that storage time did not have significant effects on the compositions of the pretreated materials and their hydrolysis by commercial enzymes. The 70 % moisture CS treated at 90 °C was used for preparation of a mix sugar hydrolysate (MSH) using combination of cellulase and xylanase. The MSH was used to prepare a corn mash at 9.5 wt% solid then subjected to ethanol fermentation by Escherichia coli KO11. The 66 % moisture CS treated at 90 °C was hydrolyzed with xylanase to make a xylose-rich hydrolysate (XRH), which was subsequently used for butyric acid fermentation by Clostridium tyrobutyricum. The resultant cellulose-enriched residue was hydrolyzed with cellulase to make a glucose-rich hydrolysate (GRH), which was subsequently used for succinic acid fermentation by E. coli AFP184.

  5. Bio-inspired dicalcium phosphate anhydrate/poly(lactic acid) nanocomposite fibrous scaffolds for hard tissue regeneration: in situ synthesis and electrospinning.

    Science.gov (United States)

    Chae, Taesik; Yang, Heejae; Ko, Frank; Troczynski, Tom

    2014-02-01

    The fundamental building blocks of hierarchically structured bone tissue are mineralized collagen fibrils with calcium phosphate nanocrystals that are biologically "engineered" through biomineralization. In this study, we demonstrate an original invention of dicalcium phosphate anhydrate (DCPA)/poly(lactic acid) (PLA) composite nanofibers, which mimics the mineralized collagen fibrils via biomimetic in situ synthesis and electrospinning for hard tissue regenerative medicines. The interaction of the Ca(2+) ions and the carbonyl groups in the PLA provides nucleation sites for DCPA during the in situ synthesis process. This resulted in the improved dispersion of DCPA nanocrystallites in the intrananoporous PLA nanofibers through electrospinning, compared to the severely agglomerated clusters of DCPA nanoparticles fabricated by conventional mechanical blending/electrospinning methods. The addition of poly(ethylene glycol), as a copolymer source, generated more stable and efficient electrospun jets and aided in the electrospinability of the PLA nanofibers incorporating the nanocrystallites. It is expected that the uniformly distributed DCPA nanocrystallites and its unique nanocomposite fibrous topography will enhance the biological performance and the structural stability of the scaffolds used for hard tissue reconstruction and regeneration.

  6. Low-temperature flux syntheses and characterizations of two 1-D anhydrous borophosphates: Na 3B 6PO 13 and Na 3BP 2O 8

    Science.gov (United States)

    Xiong, Ding-Bang; Chen, Hao-Hong; Yang, Xin-Xin; Zhao, Jing-Tai

    2007-01-01

    Two new anhydrous sodium borophosphates with one-dimensional structure, Na 3B 6PO 13(1) and Na 3BP 2O 8(2), were synthesized by low-temperature molten salts techniques using boric acid and sodium dihydrogen phosphate as flux, respectively. The crystal structures were solved by means of single-crystal X-ray diffraction ( 1, orthorhombic, Pnma (no. 62), a=9.3727(4) Å, b=16.2307(7) Å, c=6.7232(3) Å, Z=4; 2 , monoclinic, C2/ c (no. 15), a=12.567(4) Å, b=10.290(3) Å, c=10.210(3) Å, β=92.492(5)°, Z=8). Compound 1 is characterized by an infinite chain of ∞1{[BPO]} containing eight-membered rings in which all vertexes of borate groups contribute to interconnection. Compound 2 reveals an infinite straight chain ∞1{[BPO]} built of vertex-sharing four-membered rings, and chains in neighboring layers arranged along different orientations. The relations between structures and the synthetic conditions with only traced water are discussed.

  7. Enzymatic biodiesel production kinetics using co-solvent and an anhydrous medium: a strategy to improve lipase performance in a semi-continuous reactor.

    Science.gov (United States)

    Azócar, Laura; Navia, Rodrigo; Beroiz, Leticia; Jeison, David; Ciudad, Gustavo

    2014-09-25

    Enzymatic biodiesel production kinetics under previously optimized conditions were investigated. Waste frying oil (WFO) was used as the raw material, Novozym 435 as catalyst, methanol as acyl acceptor and tert-butanol as co-solvent. To investigate pure transesterification kinetics improving product properties, 3Å molecular sieves were incorporated into the reaction to provide an anhydrous medium avoiding the side reactions of hydrolysis and esterification. The effects of either WFO or methanol on the reaction rate were analyzed separately. The reaction was described by a Ping Pong mechanism and competitive inhibition by methanol. The results obtained in the kinetics study were applied in the operation of a semi-continuous reactor for biodiesel production. The operational conditions of each reaction cycle were: methanol-to-oil ratio 8/1 (mol/mol), 15% (wt) Novozym 435, 0.75% (v/v) of tert-butanol, 44.5°C, 200 rpm and 4h of reaction time. The enzymes were successively reused by remaining in the reactor during all the cycles. Under these conditions, biodiesel production yields higher than 80% over 7 reaction cycles were observed. Both the kinetics study and the reactor operation showed that Novozym 435 was not inhibited at high methanol concentrations and that the kinetics of the proposed enzymatic process could be comparable to the conventional chemical process.

  8. Controlled interactions between anhydrous keggin-type heteropolyacids and silica support: Preparation and characterization of well-defined silica-supported polyoxometalate species

    KAUST Repository

    Grinenval, Eva

    2010-11-11

    Anhydrous Keggin-type phosphorus heteropolyacids were deposited on partially dehydroxylated silica by using the surface organometallic chemistry (SOMC) strategy. The resulting solids were characterized by a combination of physicochemical methods including IR, Raman, 1D and 2D 1H, and 31P MAS NMR, electron microscopy experiments and density functional theory (DFT) calculations. It is shown that the main surface species is [ - Si(OH...H+)]2[H+]1[PM 12O403-] where the polyoxometalate is linked to the support by proton interaction with two silanols. Two other minor species (10% each) are formed by coordination of the polyoxometalate to the surface via the interaction between all three protons with three silanol groups or via three covalent bonds formed by dehydroxylation of the above species. Comparison of the reactivity of these solids and of compounds prepared by a classical way shows that the samples prepared by the SOMC approach contain ca. 7 times more acid sites. © 2010 American Chemical Society.

  9. Proposed replacement and operation of the anhydrous hydrogen fluoride supply and fluidized-bed reactor system at Building 9212. Draft environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    The US Department of Energy (DOE) proposes to replace the existing anhydrous hydrogen fluoride (AHF) supply and fluidized-bed reactor systems for the Weapons Grade Highly Enriched Uranium Chemical Recovery and Recycle Facility, Building 9212, which is Iocated within the Y-12 Plant on DOE`s Oak Ridge Reservation in Oak Ridge, Tennessee. The current AHF supply and fluidized-bed reactor systems were designed and constructed more than 40 years ago. Because of their deteriorating condition, the corrosive nature of the materials processed, and the antiquated design philosophy upon which they are based, their long-term reliability cannot be assured. The current AHF supply system cannot mitigate an accidental release of AHF and vents fugitive AHF directly to the atmosphere during operations. the proposed action would reduce the risk of exposing the Y-12 Plant work force, the public, and the environment to an accidental release of AHF and would ensure the continuing ability of the Y-12 Plant to manufacture highly enriched uranium metal and process uranium from retired weapons for storage.

  10. Proposed replacement and operation of the anhydrous hydrogen fluoride supply and fluidized-bed chemical processing systems at Building 9212, Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    The US Department of Energy (DOE) proposes to replace the existing anhydrous hydrogen fluoride (AHF) supply and fluidized-bed reactor systems for the Weapons Grade Highly Enriched Uranium Chemical Recovery and Recycle Facility, Building 9212, which is located within the Y-12 Plant on DOE`s Oak Ridge Reservation in Oak Ridge, Tennessee. The proposed replacement system would be based upon modern design criteria and safety analyses. The replacement AHF supply and distribution system equipment would be located on the existing Dock 8/8A at Building 9212. Utilities would be extended to the dock to service the process equipment. The following process equipment modules would be prefabricated for installation at the modified dock: an AHF cylinder enclosure, an AHF supply manifold and vaporizer module, an AHF sump tank and transfer skid, and an AHF supply off-gas scrubber assembly module. The fluidized-bed reactor system would be constructed in an area adjacent to the existing system in Building 9212. The replacement equipment would consist of a new reduction fluidized-bed reactor, a hydrofluorination fluidized-bed reactor, and associated air emission control equipment. The no-action alternative, which is the continued operation of the existing AHF supply and fluidized-bed reactor systems, was also evaluated.

  11. Utilization of diesel fuel, anhydrous ethanol and additives blend of a stationary diesel engine with rotatory pump; Utilizacao de mistura ternaria alcool, diesel e aditivo em motores do ciclo diesel com bomba de injecao rotativa

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Cruz, Yordanka; Cavado Osorio, Alberto [Centro de Pesquisas de Petroleo (CEINPET), Havana (Cuba); Belchior, Carlos Rodrigues Pereira; Pereira, Pedro P.; Pinto, Nauberto Rodrigues [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Tecnologia. Dept. de Engenharia Naval e Mecanica; Aranda, Donato A. Gomes [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2008-07-01

    In this paper is analyzed the performance and fuel consumption of a stationary Diesel engine, with rotary diesel fuel injection pump, using (diesel fuel + anhydrous ethanol + 0.5% additive) blend. The engine performance parameters and fuel consumption tests were performed at the Termic Machine Laboratory, located in Federal University of Rio de Janeiro, and evaluated using a MWM Series 10 model 4.10 TCA. Two test cycles were used for this test program: the tests were carried out starting from the base diesel S-500, used as a reference; the engine operated with (diesel fuel S-500 - 8% anhydrous ethanol - DIOLEFECT additive (0,5% SPAN80 + 0,1% Biomix-D)) blend. The results indicate that: the reduction levels in power and torque of engine are approximately the same which is (2,55{+-}2%), the brake specific fuel consumption increased in 1,8%. (author)

  12. Solution-state 2D NMR of ball-milled plant cell wall gels in DMSO-d6/pyridine-d5†

    Science.gov (United States)

    Ralph, John

    2014-01-01

    NMR fingerprinting of the components of finely divided plant cell walls swelled in DMSO has been recently described. Cell wall gels, produced directly in the NMR tube with perdeutero-dimethylsulfoxide, allowed the acquisition of well resolved/dispersed 2D 13C–1H correlated solution-state NMR spectra of the entire array of wall polymers, without the need for component fractionation. That is, without actual solubilization, and without apparent structural modification beyond that inflicted by the ball milling and ultrasonication steps, satisfactorily interpretable spectra can be acquired that reveal compositional and structural details regarding the polysaccharide and lignin components in the wall. Here, the profiling method has been improved by using a mixture of perdeuterated DMSO and pyridine (4:1, v/v). Adding pyridine provided not only easier sample handling because of the better mobility compared to the DMSO-d6-only system but also considerably elevated intensities and improved resolution of the NMR spectra due to the enhanced swelling of the cell walls. This modification therefore provides a more rapid method for comparative structural evaluation of plant cell walls than is currently available. We examined loblolly pine (Pinus taeda, a gymnosperm), aspen (Populus tremuloides, an angiosperm), kenaf (Hibiscus cannabinus, an herbaceous plant), and corn (Zea mays L., a grass, i.e., from the Poaceae family). In principle, lignin composition (notably, the syringyl : guaiacyl : p-hydroxyphenyl ratio) can be quantified without the need for lignin isolation. Correlations for p-coumarate units in the corn sample are readily seen, and a variety of the ferulate correlations are also well resolved; ferulates are important components responsible for cell wall cross-linking in grasses. Polysaccharide anomeric correlations were tentatively assigned for each plant sample based on standard samples and various literature data. With the new potential for chemometric analysis

  13. Crystal structures of nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper and chloro-(2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) copper

    Energy Technology Data Exchange (ETDEWEB)

    Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Paholnitcaia, A. Yu. [State University of Moldova (Moldova, Republic of); Petrenko, P. A. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I., E-mail: vtsapkov@gmail.com [State University of Moldova (Moldova, Republic of); Poirier, D. [Centre Hospitalier Universitaire de Quebec (Canada); Gulea, A. P. [State University of Moldova (Moldova, Republic of)

    2015-01-15

    Two crystal modifications of nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper (I and II) and two modifications of chloro-(2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) copper (III and IV) have been synthesized and studied by X-ray diffraction. In structures I and II, the copper atoms coordinate a monodeprotonated molecule of the organic ligand, nitrate ions, and a water molecule. In crystals of I, the complexes are monomeric, whereas complexes II are linked via nitrate ions to form polymeric chains. In both structures the coordination polyhedron of the copper atom can be described as a distorted tetragonal bipyramid—(4 + 1 + 1) in I and (4 + 2) in II. These coordination polyherdra have different compositions. In structures III and IV, the metal atoms coordinate a monodeprotonated (2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazole molecule and chloride ions. In III the complex-forming ion has square-planar coordination geometry, whereas structure IV consists of centrosymmetric dimers with two bridging chlorine atoms. It was found that nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper possesses antitumor activity.

  14. Crystal structure of poly[[μ-4-(hy-droxy-meth-yl)pyridine-κ(2) N:O][4-(hy-droxy-meth-yl)pyridine-κN](μ-thio-cyanato-κ(2) N:S)(thio-cyanato-κN)cadmium].

    Science.gov (United States)

    Werner, Julia; Jess, Inke; Näther, Christian

    2015-06-01

    The crystal structure of the title compound, [Cd(NCS)2(C6H7NO)2] n is made up of Cd(2+) cations that are coordinated by three thio-cyanate ligands and three 4-(hy-droxy-meth-yl)pyridine ligands within distorted N4OS octa-hedra. The asymmetric unit consists of one Cd(2+) cation, two thio-cyanate anions and two 4-(hy-droxy-meth-yl)pyridine ligands in general positions. Two Cd(2+) cations are linked by two μ-1,3 N- and S-bonding thio-ycanate anions into dimers which are further linked into branched chains along [100] by two μ-1,6 N- and O-bonding 4-(hy-droxy-meth-yl)pyridine ligands. One additional N-bonded 4-(hy-droxy-meth-yl)pyridine ligand and one additional N-bonded thio-cyanate anion are only terminally bonded to the metal cation. Inter-chain O-H⋯S hydrogen bonds between the hy-droxy H atoms and one of the thio-cyanate S atoms connect the chains into a three-dimensional network.

  15. Crystal structure of bis-(2,2'-bi-pyridine-κ(2) N,N')bis-(thio-cyanato-κN)mang-anese(II) 2,2'-bi-pyridine monosolvate.

    Science.gov (United States)

    Suckert, Stefan; Jess, Inke; Näther, Christian

    2015-01-01

    In the crystal structure of the mononuclear title compound, [Mn(NCS)2(C10H8N2)2]·C10H8N2, the Mn(II) cation is coordin-ated in an all-cis configuration by two N-bound thio-cyanate anions and two 2,2'-bi-pyridine ligands within a slightly distorted octa-hedral environment. The asymmetric unit consists of one Mn(II) cation, two thio-cyanate anions and two 2,2'-bi-pyridine ligands, as well as two non-coordinating 2,2'-bi-pyridine ligands that are each located on centres of inversion. In the crystal structure, the discrete [Mn(NCS)2(C10H8N2)2] complex mol-ecules are arranged in such a way that cavities are formed, in which the solvent 2,2'-bi-pyridine mol-ecules are located. Apart from van der Waals forces, there are no remarkable inter-molecular inter-actions present in the crystal structure.

  16. Crystal structure of bis-(2,2'-bi-pyridine)[N'-(quino-lin-2-ylmethylidene)pyridine-2-carbohydrazide]ruthenium(II) bis(tetra-fluorido-borate) di-chloro-methane tris-olvate.

    Science.gov (United States)

    Mori, Asami; Suzuki, Takayoshi; Nakajima, Kiyohiko

    2015-02-01

    The title compound, [Ru(C10H8N2)2(C16H12N4O)](BF4)2·3CH2Cl2, crystallizes with one complex dication, two BF4 (-) counter-anions and three di-chloro-methane solvent mol-ecules in the asymmetric unit. The central Ru(II) atom adopts a distorted octa-hedral coordination sphere with two 2,2'-bi-pyridine (bpy) and one quinoline-2-carbaldehyde (pyridine-2-carbon-yl)hydrazone (HL) ligand. The hydrazone ligand has a Z form and coordinates to the Ru(II) atom via the amide-O and imine-N atoms, affording a planar five-membered chelate ring, while its pyridine-N and quinoline-N donor atoms in the substituents are non-coordinating. The hydrazone N-H group forms an intra-molecular hydrogen bond with the quinoline-N atom. In the crystal, the quinoline moiety of HL shows the shortest π-π stacking inter-action with the pyridine substituent of HL in a neighbouring complex, the centroid-to-centroid distance being 3.793 (3) Å.

  17. Crystal structures of nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper and chloro-{2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}copper

    Science.gov (United States)

    Chumakov, Yu. M.; Paholnitcaia, A. Yu.; Petrenko, P. A.; Tsapkov, V. I.; Poirier, D.; Gulea, A. P.

    2015-01-01

    Two crystal modifications of nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper ( I and II) and two modifications of chloro-{2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}copper ( III and IV) have been synthesized and studied by X-ray diffraction. In structures I and II, the copper atoms coordinate a monodeprotonated molecule of the organic ligand, nitrate ions, and a water molecule. In crystals of I, the complexes are monomeric, whereas complexes II are linked via nitrate ions to form polymeric chains. In both structures the coordination polyhedron of the copper atom can be described as a distorted tetragonal bipyramid—(4 + 1 + 1) in I and (4 + 2) in II. These coordination polyherdra have different compositions. In structures III and IV, the metal atoms coordinate a monodeprotonated {2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazole molecule and chloride ions. In III the complex-forming ion has square-planar coordination geometry, whereas structure IV consists of centrosymmetric dimers with two bridging chlorine atoms. It was found that nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper possesses antitumor activity.

  18. Scientific Opinion on the safety and efficacy of betaine (betaine anhydrous and betaine hydrochloride) as a feed additive for all animal species based on a dossier submitted by VITAC EEIG

    OpenAIRE

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP)

    2013-01-01

    Glycine betaine (betaine) acts as a methyl group donor in transmethylation reactions in organisms. Betaine occurs in numerous vertebrate tissues as an osmolyte, ensuring osmoprotection. Betaine is safe for piglets at the maximum supplementation rate of 2 000 mg/kg complete feed with a margin of safety below 5. This conclusion is extended to all pigs and extrapolated to all animal species and categories. The use of betaine anhydrous and betaine hydrochloride as feed additives up to a supplemen...

  19. 无水乙醇预处理提取番茄红素工艺优化%Optimization of Pretreatment Process with Anhydrous EthanoI for Lycopene Extraction

    Institute of Scientific and Technical Information of China (English)

    范少丽; 敬思群; 纵伟

    2015-01-01

    Lycopene is extracted by anhydrous ethanol pretreatment method with ethyl acetate as extraction solvent and lycopene extraction rate as index.The optimal conditions of anhydrous ethanol pretreatment are obtained through single factor and orthogonal experiments,and the results show that the anhydrous ethanol pretreatment processing time is of 20 min,the processing temperature of 50 ℃, and the solid-liquid ratio of 1 ∶ 2,the number of processing stage is 2.Under these conditions, lycopene extraction rate is up to 62.45 mg/100 g and lycopene content reaches 80.69%.The modern instrumental analysis methods such as SEM,IR and XRD are applied to characterize the product,and the results show that the characterization of lycopene product and pretreatment of anhydrous ethanol is basically in accordance with the lycopene standard.%采用无水乙醇预处理番茄酱,用乙酸乙酯提取番茄红素,以番茄红素提取得率为考察指标,通过单因素和正交实验确定无水乙醇预处理最优条件为:预处理时间20 min、处理温度50℃、料液比1∶2、二级处理,番茄红素提取得率为62.45 mg/100 g,番茄红素含量可达80.69%。同时采用 SEM,IR,XRD现代仪器分析手段对番茄红素产品进行表征,结果表明无水乙醇预处理提取得到番茄红素产品表征与番茄红素标准品基本一致。

  20. A study of the aptitude of soils under natural conditions to retain radiostrontium; Etude de la vocation des sols en place a la retention du radiostrontium

    Energy Technology Data Exchange (ETDEWEB)

    Bovard, P.; Grauby, A. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Independently of the theoretical study of the propagation of radioactivity in the soil as a result of submersions or of radioactive rain, the authors have studied directly and practically how this radioactivity can vary in the actual soil. To this end a simple, rapid method has been perfected; it makes it possible to maintain for each soil sample the natural parameters (structure, humidity, etc.) without introducing boundary effects. In the laboratory, after charging the soil samples, part of the study of the propagation of radioactivity is done by autoradiography; finally, as a practical application, the study of an atomic site illustrates the methods described. (author) [French] Independamment de l'etude theorique de la propagation de la radioactivite dans le sol a la suite de submersions ou de pluies radioactives, les auteurs ont etudie directement et pratiquement comment pourrait evoluer cette radioactivite dans les sols en place. Pour cela, une methode simple et rapide a ete mise au point; elle permet de conserver pour chaque echantillon de sol, les parametres naturels (structure, humidite, etc...), sans introduire d'effets de paroi. En laboratoire, apres mise en charge des massifs preleves, une partie de l'etude de la propagation des radioelements est realisee par autoradiographie; enfin, une application pratique, l'etude d'un site atomique, illustre l'expose. (auteur)