WorldWideScience

Sample records for alkoxides synthesis structure

  1. Synthesis and characterization of sodium alkoxides

    Indian Academy of Sciences (India)

    These compounds were characterized using X-ray diffraction technique and IR spectroscopy. The elemental analysis was carried out by CHNS analyser and atomic emission spectroscopy. Normal chain sodium alkoxides were found to exhibit tetragonal crystal structure. Crystal structures of sodium ethoxide and sodium ...

  2. Direct synthesis of some significant metal alkoxides

    International Nuclear Information System (INIS)

    Emilio, Gule Buyu

    1998-11-01

    Investigations were carried out with an attempt to study direct synthesis of metal alkoxides from elemental metals and appropriate alcohols. These were done by reacting representative metals of group I, II, III 7 IV (which are Na, Mg, Al and Sn respectively) directly with dry ethanol and dry isopropanol. The products were then analysed by infrared spectrophotometer to meter to identify metal alkoxides formed. Ethanol was found to have more acidic character in reactions with these metals than isopropanol, thus its reactions with the metals were faster. Reduction in the acidic character of isopropanol, a secondary alcohol, could be due to the existence off more alkyl groups in the molecule which displays +1 inductive effect. For the same alcohol the metals reactions were found to decrease with increase in electronegativity of the metals. Sodium being the least electronegative metal reacted fasted while tin the more electronegative metal reacted slowest. Mg, Al and Sn required a catalyst,, mercury (II) chloride and heat in order to initiate and drive the reactions completion. The alkoxides formed were found to be soluble to a certain extent in the tow alcohols and the order of solubility is such that Sn≥ Al ≥ Mg ≥ Na.(Author)

  3. All-alkoxide synthesis of strontium-containing metal oxides

    Science.gov (United States)

    Boyle, Timothy J.

    2001-01-01

    A method for making strontium-containing metal-oxide ceramic thin films from a precursor liquid by mixing a strontium neo-pentoxide dissolved in an amine solvent and at least one metal alkoxide dissolved in a solvent, said at least one metal alkoxide selected from the group consisting of alkoxides of calcium, barium, bismuth, cadmium, lead, titanium, tantalum, hafnium, tungsten, niobium, zirconium, yttrium, lanthanum, antimony, chromium and thallium, depositing a thin film of the precursor liquid on a substrate, and heating the thin film in the presence of oxygen at between 550 and 700.degree. C.

  4. Modification of zirconium and hafnium alkoxides : the effect of molecular structure on derived materials

    NARCIS (Netherlands)

    Spijksma, G.I.

    2006-01-01

    This thesis deals with the influence of modifying ligands on the structure and stability of zirconium and hafnium precursors. The applicability of the obtained modified alkoxides has been evaluated for MOCVD and sol-gel. Furthermore, the influence of the introduction of heteroligands on the sol-gel

  5. metal alkoxides

    Indian Academy of Sciences (India)

    substituent effects in the head-to-tail double insertion reactions observed ... an internal standard. The yield of diphenyl carbodii- mide was further verified by isolating it as diphenyl urea after hydrolysis. The organic fraction obtained in the catalytic metathesis .... insertion of PhNCO into metal alkoxide 1a to generate. Table 1.

  6. STUDY OF THE EFFECT OF MIXED ALKOXIDES OXYPROPYLATED AROMATIC SECONDARY AMINES ON THE STRUCTURE OF DIENE POLYMERS

    Directory of Open Access Journals (Sweden)

    A. V. Firsova

    2014-01-01

    Full Text Available Summary. This article discusses the relationship structure of the diene and styrene-butadiene copolymers (SBR, the structure of the part of the initiating system of n-butyl lithium + modifier, which is a mixed alkoxide of an alkali and alkaline earth metals, which allows to control the microstructure of the diene polymer and its molecular weight characteristics. Alcohol derivatives selected high-boiling alcohols tetra (hydroxypropyl ethylenediamine (lapromol - 294 and tetrahydrofurfuryl alcohol (TGFS. The scheme of obtaining styrene-butadiene random copolymers (SBR with a high content (64 ± 4 % of vinyl units was developed. The process of copolymerization with sodium-calcium-lithium complex Са(С4Н9 2 • С4Н9Na • LiOR was carried out. After water decontamination residues deactivated complex remain in the polymer as a filler. Studied the copolymerization of butadiene with styrene in the presence of lithium amide, which is obtained on the basis of the alcohols containing the group - NH -. With the increasing solubility of the branching alkoxides increases in hydrocarbon solvents. Found that sodium alkoxide hydroxypropyl aniline decane insoluble, the sodium alcoholate hydroxypropyl toluidine soluble in decane. The results of studies of the effect of mixed alkoxides oxypropylated aromatic secondary amines on the structure of diene polymers. The Providing the necessary initiation systems for preparing functionalized polymers. It was revealed that secondary amines from which the lithium amides are inactive, so the polymerization of monomers was carried out in the presence of electron as that used glycol ethers - diglyme, THF, 2,2 - ditetragidrofurfuril propane, which increase polymer-filler interaction. The results of research of the microstructure of the diene part of SBR obtained in the mixed alkali metal alkoxide with a mixture of lapromol alcohols, toluidine and TGFS showed that increasing toluidine consisting of mixed modifier reduces

  7. New inorganic (an)ion exchangers based on Mg–Al hydrous oxides: (Alkoxide-free) sol–gel synthesis and characterisation

    KAUST Repository

    Chubar, Natalia

    2011-05-01

    New inorganic ion exchangers based on double Mg-Al hydrous oxides were generated via the new non-traditional sol-gel synthesis method which avoids using metal alkoxides as raw materials. Surface chemical and adsorptive properties of the final products were controlled by several ways of hydrogels and xerogels treatments which produced the materials of the layered structure, mixed hydrous oxides or amorphous adsorbents. The final adsorptive materials obtained via thermal treatment of xerogels were the layered mesoporous materials with carbonate in the interlayer space, surface abundance with hydroxylic groups and maximum adsorptive capacity to arsenate. Higher affinity of Mg-Al hydrous oxides towards H2AsO4- is confirmed by steep adsorption isotherms having plateau (removal capacity) at 220. mg[As]. gdw-1 for the best sample at pH = 7, fast adsorption kinetics and little pH effect. Adsorption of arsenite, fluoride, bromate, bromide, selenate, borate by Mg-Al hydrous oxides was few times high either competitive (depending on the anion) as compare with the conventional inorganic ion exchange adsorbents. © 2011 Elsevier Inc.

  8. Metal alkoxides as starting materials for hydrolysis processes

    International Nuclear Information System (INIS)

    Mukhtar, Omaima Awad

    1999-12-01

    In this thesis the preparation of some metal alkoxides and their hydrolysis products were studied. The characteristic of each prepared alkoxides and their hydrolyzates were determined. Tetra ethoxysilane was prepared by the elemental route (the reaction of silicon powder with liquid ethanol) in the presence of tin ethoxide as a catalyst. The use of tin alkoxide is considered one of the most developed ways used recently in chemistry, compared to the usage of acids and bases as catalyst previously. It had been confirmed by the usage of (infrared) IR spectroscopy, the structure of the prepared material. Also tin isopropoxide had been prepared and hydrolyzed. Ethoxides of aluminium, magnesium and tin had been prepared by the elemental route. The gelation product had been analyzed. tetraethoxysilane had been also prepared by the halosilane route. Isopropoxide of each aluminium, magnesium and tin had been synthesized, hydrolyzed, allowed to gel and analyzed by IR (infrared) spectroscopy and gas-liquid chromatography. However, results obtained indicated that tin ethoxide is an effective catalyst in the direct synthesis of tetraethoxysilane from silicon powder and liquid ethanol. Gas-liquid chromatography, infra-red (IR) analysis showed that the final reaction product was tetraethoxysilane. (Author)

  9. Preparation of oxide materials from metal alkoxides

    International Nuclear Information System (INIS)

    Turevskaya, E.P.; Turova, N.Ya.; Yanovskaya, M.I.

    2000-01-01

    The results of studies on the sol-gel technologies on the basis of alkoxides are presented. The synthesis and properties of titanates zirconates, niobates, tantalates, vanadates and solid solutions on the basis of Mo, W and Bi oxides, iron oxides and high-temperature superconductors are presented. The most important aspects, determining the choice of optimal conditions for preparation of oxides of concrete compositions with required properties are pointed out. Accomplishment of the whole chain of studies made it possible to synthesize a broad range of metal alkoxides and study their properties and also carry out large-scale studies on preparation of various oxides and materials on the basis thereof, using the source base of the sol-gel method [ru

  10. Preparation of Layer-Structured CaBi2Ta2O9 Ferroelectric Thin Films through a Triple Alkoxide Route

    Science.gov (United States)

    Kato, Kazumi; Suzuki, Kazuyuki; Nishizawa, Kaori; Miki, Takeshi

    2000-09-01

    A triple alkoxide solution for CaBi2Ta2O9 (CBT) thin films was prepared. CBT thin films were deposited on Pt-passivated silicon and Pt-passivated quartz glass substrates. The thin films on Pt-passivated silicon crystallized to form the perovskite structure at low temperatures and showed preferred orientation along the c-axis. The thin films did not show ferroelectric P-E hysteresis loops. In contrast, the 750°C-annealed thin film on Pt-passivated quartz glass showed random orientation and exhibited excellent P-E hysteresis loops. The remanent polarization (Pr) and the coercive electric field (Ec) at 13 V were 6.9 μC/cm2 and 170 kV/cm, respectively.

  11. Aluminium(III) alkoxides as unique synthons for heterocyclic ...

    Indian Academy of Sciences (India)

    Administrator

    Facile reactivity of aluminium(III) alkoxides with organic protic reagents with alcohol as the only side product provides a convenient method for the synthesis of a variety of products which may not be synthesized by any other route. The possibility of removal of alcohol azeotropically with solvent benzene makes it possible to ...

  12. Alkoxide routes to Inorganic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, George Harrison [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2007-12-01

    An all alkoxide solution chemistry utilizing metal 2-methoxyethoxide complexes in 2-methoxyethanol was used to deposit thin-films of metal oxides on single-crystal metal oxide substrates and on biaxially textured metal substrates. This same chemistry was used to synthesize complex metal oxide nanoparticles. Nuclear Magnetic Resonance spectroscopy was used to study precursor solutions of the alkaline niobates and tantalates. Film crystallization temperatures were determined from x-ray diffraction patterns of powders derived from the metal oxide precursor solutions. Film structure was determined via x-ray diffraction. Film morphology was studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Epitaxial thin-films of strontium bismuth tantalate (SrBi{sub 2}Ta{sub 2}O{sub 9}, SBT) and strontium bismuth niobate (SrBi{sub 2}Nb{sub 2}O{sub 9}, SBN) were deposited on single crystal [1 0 0] magnesium oxide (MgO) buffered with lanthanum manganate (LaMnO{sub 3}, LMO). Epitaxial thin films of LMO were deposited on single crystal [100] MgO via Rf-magnetron sputtering and on single crysal [100] lanthanum aluminate (LaAlO{sub 3}) via the chemical solution deposition technique. Epitaxial thin-films of sodium potassium tantalate (na{sub 0.5}K{sub 0.5}TaO{sub 3}, NKT), sodium potassium niobate (Na{sub 0.5}K{sub 0.5}NbO{sub 3}, NKN) and sodium potassium tantalum niobate (Na{sub 0.5}K{sub 0.5}Ta{sub 0.5}O{sub 3}, NKTN) were deposited on single crystal [1 0 0] lanthanum aluminate and [1 0 0] MgO substrates (NKT and NKN) and biaxially textured metal substrates via the chemical solution deposition technique. Epitaxial growth of thin-films of NKT, NKN and NKTN was observed on LAO and Ni-5% W. Epitaxial growth of thin-films of NKN and the growth of c-axis aligned thin-films of NKT was observed on MgO. Nanoparticles of SBT, SBN, NKT and NKN were synthesized in reverse micelles from alkoxide precursor solutions. X-ray diffraction and transmission electron

  13. Alternating Sequence Controlled Copolymer Synthesis of α-Hydroxy Acids via Syndioselective Ring-Opening Polymerization of O-Carboxyanhydrides Using Zirconium/Hafnium Alkoxide Initiators.

    Science.gov (United States)

    Sun, Yangyang; Jia, Zhaowei; Chen, Changjuan; Cong, Yong; Mao, Xiaoyang; Wu, Jincai

    2017-08-09

    The ring-opening polymerization (ROP) of O-carboxyanhydrides (OCAs) can give diverse poly(α-hydroxy acid)s (PAHAs) with different functional groups because of easy modification of the side group of OCAs, which can extend applications of PAHAs widely. The stereoselective polymerization of O-carboxyanhydrides and further sequence controlled alternating copolymerization of OCAs were still big challenges until now for lack of suitable catalysts/initiators. In this work, a highly syndioselective ROP of OCAs system as the first stereoselective example in this area is reported using zirconium/hafnium alkoxides as initiators with the highest P r value up to 0.95. Furthermore, these initiators were successfully applied in the precisely alternating sequence controlled copolymerization of PheOCA and Tyr(Bn)OCA, and alternating copolymerization of LacOCA and PheOCA was also achieved.

  14. Crystal structures of a novel NNN pincer ligand and its dinuclear titanium(IV alkoxide pincer complex

    Directory of Open Access Journals (Sweden)

    Jakub Pedziwiatr

    2017-02-01

    Full Text Available This report describes a synthetic protocols and the crystal structures involving a novel pincer-type H3[NNN] ligand, namely di-μ-bromido-μ-{2-(2,2-dimethylpropanimidoyl-N-[2-(2,2-dimethylpropanimidoyl-4-methylphenyl]-4-methylaniline}-bis[(diethyl etherlithium], [Li2Br2(C24H33N3(C4H10O2] (1 and a dinuclear metal complex, namely di-μ-bromido-2:3κ4Br:Br-bis{2-(2,2-dimethylpropanimidoyl-N-[2-(2,2-dimethylpropanimidoyl-4-methylphenyl]-4-methylaniline}-1κ3N,N′,N′′;4κ3N,N′,N′′-tetra-μ-isopropanolato-1:2κ4O:O;3:4κ4O:O-diisopropanolato-1κO,4κO-2,3-dilithium-1,4-dititanium, [Li2Ti2Br2(C24H32N32(C3H7O6] or {[NHNNH]Ti(OiPr3(LiBr2}2 (2. Complex 1, which sits on a twofold rotation axis, is a rare example of a pincer-type ligand which bears ketimine side arms. A unique feature of complex 1 is that the ketimine N atoms have an LiBr(Et2O fragment bonded to them, with the Li atom adopting a distorted tetrahedral geometry. This particular fragment creates an LiBr bridge between the two ketimine sidearms, which leads to a cage-type appearance of the ligand. Complex 2 consists of the previously described ligand and a TiIV metal atom in an octahedral environment, and is located on an inversion center. Complex 2 crystallizes as a dinuclear species with the metal atoms being bridged by an LiBr entity [the Br atoms are disordered and refined in two positions with their site occupation factors refining to 0.674 (12/0.372 (12], and the Li cation being bonded to the isopropoxide O atoms (Li having a tetrahedral coordination as in 1. The organic ligand of compound 2 exhibits disorder in its periphery groups; isopropyl and tert-butyl groups (occupation factors fixed at 0.6/0.4. The novel [NNN]H3 pincer-type ligand was characterized by multinuclear and multidimensional NMR, HRMS and X-ray crystallography. The dinuclear metal complex 2 was characterized by X-ray crystallography. Although each structure exhibits donor N—H groups, no hydrogen bonding

  15. Applications versus properties of Mg–Al layered double hydroxides provided by their syntheses methods: Alkoxide and alkoxide-free sol–gel syntheses and hydrothermal precipitation

    KAUST Repository

    Chubar, Natalia

    2013-12-01

    A tremendous number of studies have examined layered double hydroxides (LDH) for their technological applications in the ion exchange removal of toxic ions, recovery of valuable substances, catalysis, CO2 capture, as a layered host for storage/delivery of biologically active molecules, additives to plastics and building materials, and other functions. Numerous publications always conclude that the materials (prepared, as a rule, using the oldest synthesis method) are very promising for each investigated application; however, the main chemical industries producing these materials advertise them mainly (or only) as plastic additives. The authors performed extensive research using many of the appropriate methods to compare the structure, surface and adsorptive properties of three Mg-Al LHDs produced by advanced synthesis methods. One industrial sample (by Sasol, Germany) prepared by the alkoxide sol-gel method and two novel Mg-Al LDHs synthesised in-house by alkoxide-free sol-gel and hydrothermal precipitation approaches were investigated. Reasons for the very different adsorptive selectivity of the three LDHs towards arsenate, selenate, phosphate, arsenite and selenite have been provided, highlighting the role of speciation of the interlayer carbonate, aluminium, magnesium, interlayer hydration and moisture content in the adsorptive selectivity towards each toxic anion. This work is the first report presenting the regularities of the LDHs structure, surface and anion exchange properties as a function of their syntheses method. It establishes the links to potential technological applications of each investigated LDH and explains the necessary properties required to make the technological application cost-effective and efficient. The paper might accelerate industrial applications of these advanced materials. © 2013 Elsevier B.V.

  16. Multidentate Fluorinated Alkoxide Ligand Platforms for Oxophilic Metal Centers: From MOCVD Source Reagents to Polymerization Catalysts

    OpenAIRE

    Carpentier, Jean-François

    2010-01-01

    International audience; In contrast to simple fluorinated alkoxides, the coordination chemistry of multidentate ligands that incorporate OC(CF3)2CR2-type moieties and additional donors (N, O, etc.) has been briefly investigated. In this Perspective, we review some well-defined, unambiguously authenticated main group and transition metal complexes supported by multidentate fluorinated alkoxide ligands and we present aspects of their syntheses, structures, and reactivities. The first part is de...

  17. Alkoxide-based precursors for direct electrospinning of alumina fibers

    Science.gov (United States)

    Maneeratana, Vasana

    The vision for space exploration in 2004 reinvigorated excitement that was engendered during the 1960's space race. Looking to assist NASA's agency wide mission to develop new technologies to enhance space travel, it is the ultimate goal of this work to support future missions with a hand-held electrospinning apparatus to instantaneously repair existing crucial ceramic fiber structures, such as spacesuits, insulative foams, and tiles. In this research, a new type of precursor is designed based from aluminum alkoxide-based precursors, since alumina serves as a base material for a majority of high-temperature applications. The structure-processing behavior of these precursors is subsequently studied. New precursors of aluminum alkoxides were prepared by modifying solutions; as a result various types of structures were produced, ranging from continuous hollow fibers, continuous solid fibers, or hollow particles. Direct electrospinning with these alkoxide-based precursors yielded an average of 1.9 g/hr of Al2O3, compared to literature with the highest theoretical yield calculated to be 0.68 g/hr. Further exploration of electrospinning parameters found that flow rate directly related to exposure times; therefore fibers were produced in the atmosphere through hydrolysis/condensation with simultaneous solvent evaporation. Furthermore other processing parameters, including the effect of the microstructure due to processing in an electric field were studied. It was found that electrospinning promotes the reaction of the alkoxide, which thereby reduces trapped solvents. As a result of firing schedules, the fibers' hollow features were preserved, and precursors with volatile species resulted in near net shaped fibers. At low firing temperatures, specific surface areas in the range of 330-345 m 2/g were found electrospun fibers. Additionally modified precursors lowered alpha transitions of fibers down to ˜900°C.

  18. Influence of chelation ratio of metal alkoxides on aging of PZT 53/47 ...

    Indian Academy of Sciences (India)

    Administrator

    GDL-Ameca km 45.5, CP 46600 Ameca, Jalisco, Mexico. MS received 21 September 2013. Abstract. The high reactivity of metal alkoxides, common starting reagents in sol–gel-based synthesis routes, generally demands the use of chelating agents in order to avoid fast hydrolysis and also to allow an easier manipulation of ...

  19. Probing the Effect of Six-Membered N-Heterocyclic Carbene—6-Mes—on the Synthesis, Structure and Reactivity of Me2MOR(NHC (M = Ga, In Complexes

    Directory of Open Access Journals (Sweden)

    Martyna Cybularczyk-Cecotka

    2018-02-01

    Full Text Available The investigation of the reactivity of six membered N-heterocyclic carbene 1,3-bis(2,4,6-trimethylphenyl-3,4,5,6-tetrahydropyrimidin-1-ylidene (6-Mes towards dialkylgallium and dialkylindium alkoxides/aryloxides has shown that both steric hindrances and donor properties of 6-Mes significantly influence the strength of M–C6-Mes bond, as well as the formation, structure and reactivity of Me2MOR(6-Mes (M = Ga, In complexes. While the reactions of simple dimethylgallium alkoxides with 6-Mes lead to the formation of stable monomeric Me2Ga(OCH2CH2OMe(6-Mes (1 and Me2GaOMe(6-Mes complexes, the analogous Me2InOR(6-Mes are unstable and disproportionate to methylindium alkoxides and Me3In(6-Mes (2. The use of bulky alkoxide ligand—OCPh2Me or aryloxide ligand—OC6H4OMe allowed for the synthesis of stable Me2M(OCPh2Me(6-Mes (M = Ga (3 and In (4 as well as Me2M(OC6H4OMe(6-Mes (M = Ga (5 and In (6. The structures of 1–6 have been determined using both spectroscopic methods in solution and X-ray diffraction studies, which confirmed the effect of both steric hindrances and donor properties of 6-Mes on their structure and catalytic properties in the ring-opening polymerization (ROP of rac-lactide.

  20. Synthesis and characterization of sodium alkoxides

    Indian Academy of Sciences (India)

    Unknown

    Ethanol + 10% H2O. (Mukaibo et al 1978). Japan. OEC, MONJU. Ethanol + 10% H2O. (Nakai et al 1997). UK. Dounreay Nuclear Power Establishment Butyl cellosolve. (Donaldson and Bray 1978). USA. 1. SRDA ..... don: The English Language Book Society and Longman. Group Ltd) 4th ed. Ganesan V, Krishnamoorthy D ...

  1. Synthesis and characterization of sodium alkoxides

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Alcohol route is being adopted for cleaning sodium from sodium-wetted small components of coolant circuits of fast reactors. For better understanding of sodium–alcohol reactions and their energetics, the data on thermo-chemical properties such as heats of sodium–alcohol reactions, heats of dissolution, heat ...

  2. Aggregation and hydrolysis reactions of bismuth alkoxides

    International Nuclear Information System (INIS)

    Whitmire, K.H.; Jones, C.M.; Burkart, M.D.; Hutchinson, J.C.; McKnight, A.L.

    1992-01-01

    This paper reports that new bismuth alkoxide and oxo-alkoxide complexes have been prepared from the salt metathesis reaction of NaOR with BiCl 3 . When R = CH(CF 3 ) 2 , the product is [Bi(μ-OR)(OR) 2 (THF)] 2 . similar work with R = C 6 F 5 has not yielded a simple alkoxide, but complexes of formulation NaBi 3 (μ 3 -O)(OR) 8 (THF), NaBi 4 (μ 3 -O) 2 (OR) 9 (THF) 2 , Na 2 Bi 4 (μ 3 -O) 2 (OR) 10 and Bi 6 (μ 3 -OR)(μ 3 -O) 4 [μ 3 -OBI(OR) 4 ] 3 have been observed. The reaction of BiPh 3 with HOC 6 F 5 , however, did produce the desired alkoxide which has been characterized as [Bi(OR) 2 (μ-OR)(toluene)] 2 and [Bi(OR) 2 (μ-OR)(toluene)] 2 · 2 toluene. The reaction of this alkoxide with NaOC 6 F 5 led to the production of Bi 6 (μ 3 -O) 2 (μ 4 -O)(OR) 12 and NaBi 3 (μ 3 -O)(OR) 8 (THF) 3 . Reaction of BiPh 3 with HOC 6 F 5 in THF led to the formation of Bi 6 (μ 3 -OR)(μ 3 -O) 4 [μ 3 -OBi(OR) 4 ] 3 (THF) 2 . Surprisingly the reaction of BiEt 3 and HOR (R = C 6 F 5 or Ph) displaced only one Et group to give [Et 2 Bi(μ-OR)] oo which exist as infinite chain polymers with alternating Bi-O-Bi backbones. These spiral chains form chiral helices in the crystal lattice. The discovery of high T C superconducting copper oxide phases containing bismuth, lead and thallium has led to this investigation

  3. Nanostructure Development in Alkoxide-Carboxylate-Derived Precursor Films of Barium Titanate

    NARCIS (Netherlands)

    Stawski, Tomasz; Veldhuis, Sjoerd; Besselink, R.; Castricum, H.L.; Portale, G.; Blank, David H.A.; ten Elshof, Johan E.

    2012-01-01

    The structural evolution in wet alkoxide-carboxylate sol–gel precursor films of barium titanate upon drying was investigated by time-resolved small-angle X-ray scattering (SAXS). The morphology of as-dried amorphous precursor thin films was investigated by transmission electron microscopy (TEM) and

  4. Water-soluble titanium alkoxide material

    Science.gov (United States)

    Boyle, Timothy J.

    2010-06-22

    A water soluble, water stable, titanium alkoxide composition represented by the chemical formula (OC.sub.6H.sub.6N).sub.2Ti(OC.sub.6H.sub.2(CH.sub.2N(CH.sub.3).sub.2).sub- .3-2,4,6).sub.2 with a theoretical molecular weight of 792.8 and an elemental composition of 63.6% C, 8.1% H, 14.1% N, 8.1% O and 6.0% Ti.

  5. Structural synthesis of parallel robots

    CERN Document Server

    Gogu, Grigore

    This book represents the fifth part of a larger work dedicated to the structural synthesis of parallel robots. The originality of this work resides in the fact that it combines new formulae for mobility, connectivity, redundancy and overconstraints with evolutionary morphology in a unified structural synthesis approach that yields interesting and innovative solutions for parallel robotic manipulators.  This is the first book on robotics that presents solutions for coupled, decoupled, uncoupled, fully-isotropic and maximally regular robotic manipulators with Schönflies motions systematically generated by using the structural synthesis approach proposed in Part 1.  Overconstrained non-redundant/overactuated/redundantly actuated solutions with simple/complex limbs are proposed. Many solutions are presented here for the first time in the literature. The author had to make a difficult and challenging choice between protecting these solutions through patents and releasing them directly into the public domain. T...

  6. Characterisation of a new alkoxide sol-gel hydroxyapatite

    International Nuclear Information System (INIS)

    Green, D.D.; Kannangara, G.S.K.; Milev, A.; Ben-Nissan, B.

    1999-01-01

    Hydroxyapatite (HAp) coatings have been used to promote bone growth and fixation towards implant surfaces to encourage faster recovery times for the recipient. Current coating processing techniques, capable of producing thin HAp layers are pulsed-laser deposition and sputtering (high-temperature processing). Other technologies are in vitro methods, electrodeposition and sol-gel, due to the fact that these techniques utilise lower processing temperatures they avoid structural instabilities of HAp at elevated temperatures. The term sol-gel encompasses any process of producing ceramic materials (single and mixed oxides, as well as non-oxides e.g. nitrides) from solutions. The sol-gel process was first identified by Ebelman, and has been used to produce ceramic powders, coatings, and bulk materials including glasses. The implementation of a sol-gel methodology enables increased stoichiometry and homogeneity, while having the ability to coat complex shapes. Sol-gel hydroxyapatite reported by Chai et al. employed tri ethyl phosphite [ P(OEt) 3 ] as the staring phosphorus alkoxide precursor, whereby it was established that in order to obtain monophasic hydroxyapatite upon firing there must be a 24 hour ripening period. The ripening period was determined to be an equilibrium step whereby the equilibrium intermediate phase lied in favour of a diethyl phosphite arrangement (species) within the sol. Therefore, the work here under taken was to produce hydroxyapatite using diethyl phosphite [HOP(OEt) 2 ] as a starting alkoxide precursor with a final aim to reduce or eliminate the ageing period as observed by Chai et al in P(OEt) 3 solutions

  7. NMR and IR spectroscopic examination of the hydrolytic stability of organic ligands in metal alkoxide complexes and of oxygen bridged heterometal bonds

    OpenAIRE

    Hoebbel, Dagobert; Reinert, Thomas; Schmidt, Helmut K.

    1996-01-01

    IR and 13C NMR investigations of the hydrolytic stabilites of the saturated and unsaturated beta-keto ligands acetylacetone (ACAC), ethylacetoacetate (EAA), allylacetoacetate (AAA), methacryloxyethyl-acetoacetate (MEAA) of the Al-, Ti- and Zr-butoxide complexes show a strong dependence on the type of the metal alkoxide and the structure of the organic ligands. The hydrolytic stabilities of the ligands decrease in the order Al-Zr-Ti-alkoxide and ACAC>AAA>EAA>=MEAA. Sol-gel reactions of complex...

  8. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    International Nuclear Information System (INIS)

    Dolmatov, Valerii Yu

    2007-01-01

    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  9. SYNTHESIS, STRUCTURE AND PHOTOLUMINESCENCE OF ...

    African Journals Online (AJOL)

    Preferred Customer

    dimensional supramolecular framework. ... The growing interest in the field of the crystal engineering of inorganic-organic hybrid materials .... Synthesis, structure and photoluminescence of (HgCl3)n(C6NO2H6)n(C6NO2H5)n nH2O. Bull. Chem.

  10. Multidentate fluorinated alkoxide ligand platforms for oxophilic metal centers: from MOCVD source reagents to polymerization catalysts.

    Science.gov (United States)

    Carpentier, Jean-François

    2010-01-07

    In contrast to simple fluorinated alkoxides, the coordination chemistry of multidentate ligands that incorporate OC(CF(3))(2)CR(2)-type moieties and additional donors (N, O, etc.) has been briefly investigated. In this Perspective, we review some well-defined, unambiguously authenticated main group and transition metal complexes supported by multidentate fluorinated alkoxide ligands and we present aspects of their syntheses, structures, and reactivities. The first part is devoted to the first syntheses of fluorinated alkoxy-imino and fluorinated alkoxy-amino ligand platforms and their application in the preparation of late transition (Ru, Co, Ir, Ni, Pd, Cu) and main group (Sr, Ba, Ga) metal complexes, many of which have been used as chemical vapor deposition (CVD) source reagents. In the second part, heteroleptic complexes based on oxophilic metals (Y, La, Ti, Zr, Hf, Al) and the catalytic performance of these systems in olefin polymerization and ring-opening polymerization (ROP) of cyclic esters are highlighted.

  11. synthesis and structures

    Indian Academy of Sciences (India)

    Priya Saxena

    2017-08-29

    Aug 29, 2017 ... complexes as well as for biological applications.16–24. Of particular mention here are the nickel and palladium complexes of ..... tion and indexing were performed with CrysAlisPro software suite.42 WinGX module was used to perform all the cal- culations.43 The structures were solved by direct methods.

  12. The Obtaining of Nano Oxide Systems SiO2-REE with Alkoxide Technology

    Science.gov (United States)

    Amelina, Anna; Grinberg, Evgenii

    A lot of oxides systems with REE as dopants are used in catalytic processes in organic synthesis. They are very perspectives as thermostable coating in aerospace technics. These systems are usually based on silicon or aluminium oxides and doped with rare-earth elements. This systems can be produced by different methods. One of the most perspective of them is “sol-gel”-method with silicium, aluminium and rare-earth alkoxides as a precursor of doped silica and alumina, or their derivatives. Thus the obtaining of composite SiO _{2} - REE oxide materials by the hydrolysis doped with rare-earth elements was suggested. Some of alcoholate derivatives such as El(OR)n were used in this processes. The SiO _{2}- REE oxides were precipitated during the sol-gel process, where tetraethoxysilane (TEOS) as used as SiO _{2} sources. Also it is known that alkoxides of alkali metals, including lithium alkoxides, are widely used in industry and synthetic chemistry, as well as a source of lithium in various mixed oxide compositions, such as lithium niobate, lithium tantalate or lithium silicate. Therefore, we attempted to obtain the lithium silicate, which is also doped with rare-earth elements. Lithium silicate was obtained by alkaline hydrolysis of tetraethoxysilane with lithium alkoxide. Lithium alkoxide were synthesized by dissolving at metal in the corresponding alcohol are examined. The dependence of the rate of dissolving of the metal on the method of mixing of the reaction mixture and the degree of metal dispersion was investigated. The mathematical model of the process was composed and also optimization of process was carried out. Some oxide SiO _{2}, Al _{2}O _{3} and rare-earth nanostructured systems were obtained by sol-gel-method. The size of particle was determined by electron and X-ray spectroscopy and was in the range of 5 - 15 nm. Purity of this oxide examples for contaminating of heavy metals consists n.(1E-4...1E-5) wt%. Sols obtained by this method may be used

  13. Strong influence of polymer architecture on the microstructural evolution of hafnium-alkoxide-modified silazanes upon ceramization.

    Science.gov (United States)

    Papendorf, Benjamin; Nonnenmacher, Katharina; Ionescu, Emanuel; Kleebe, Hans-Joachim; Riedel, Ralf

    2011-04-04

    The present study focuses on the synthesis and ceramization of novel hafnium-alkoxide-modified silazanes as well as on their microstructure evolution at high temperatures. The synthesis of hafnia-modified polymer-derived SiCN ceramic nanocomposites is performed via chemical modification of a polysilazane and of a cyclotrisilazane, followed by cross-linking and pyrolysis in argon atmosphere. Spectroscopic investigation (i.e., NMR, FTIR, and Raman) shows that the hafnium alkoxide reacts with the N-H groups of the cyclotrisilazane; in the case of polysilazane, reactions of N-H as well as Si-H groups with the alkoxide are observed. Consequently, scanning and transmission electron microscopy studies reveal that the ceramic nanocomposites obtained from cyclotrisilazane and polysilazane exhibited markedly different microstructures, which is a result of the different reaction pathways of the hafnium alkoxide with cyclotrisilazane and with polysilazane. Furthermore, the two prepared ceramic nanocomposites are unexpectedly found to exhibit extremely different high-temperature behavior with respect to decomposition and crystallization; this essential difference is found to be related to the different distribution of hafnium throughout the ceramic network in the two samples. Thus, the homogeneous distribution of hafnium observed in the polysilazane-derived ceramic leads to an enhanced thermal stability with respect to decomposition, whereas the local enrichment of hafnium within the matrix of the cyclotrisilazane-based sample induces a pronounced decomposition upon annealing at high temperatures. The results indicate that the chemistry and architecture of the precursor has a crucial effect on the microstructure of the resulting ceramic material and consequently on its high-temperature behavior. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Hydrolytic activity of -alkoxide/acetato-bridged binuclear Cu (II ...

    Indian Academy of Sciences (India)

    Two -alkoxide/acetate-bridged small molecule binuclear copper(II) complexes were synthesized, and used to promote the hydrolysis of a classic carboxylic acid ester, -nitrophenyl picolinate (PNPP). Both binuclear complexes exhibited good hydrolytic reactivity, giving rise to . 15547- and 17462-fold acceleration over ...

  15. Preparation of titanium diboride powders from titanium alkoxide and ...

    Indian Academy of Sciences (India)

    Administrator

    esting engineering ceramic material which can be used as ballistic armor ... such as metal oxides and ceramics. In the process, reactive metal precursors were initially hydrolyzed, followed by condensation and polymerization reactions. Metal alkoxides are metal- .... bide was studied. Process parameters were optimized to.

  16. Synthesis, spectroscopic characterization and electronic structure of ...

    Indian Academy of Sciences (India)

    Unknown

    Copper(I) carbene complex; carbene complex synthesis; Cu(I)–carbene electronic structure. 1. Introduction. Metal carbene complexes are arguably the most ver- satile organometallic reagents that have been devel- oped for organic synthesis.1 Different reactions of these complexes have been reported since their dis-.

  17. Standard molar enthalpies of formation of sodium alkoxides

    International Nuclear Information System (INIS)

    Chandran, K.; Srinivasan, T.G.; Gopalan, A.; Ganesan, V.

    2007-01-01

    The molar enthalpies of solution of sodium in methanol, ethanol, and n-propanol and of sodium alkoxides in their corresponding alcohols were measured at T=298.15K using an isoperibol solution calorimeter. From these results and other auxiliary data, the standard molar enthalpies of formation, Δ f H m o (RONa,cr) of sodium methoxide, sodium ethoxide, and sodium n-propoxide were calculated and found to be {(-366.21+/-1.38) (-413.39+/-1.45), and (-441.57+/-1.18)}kJ.mol -1 , respectively. A linear correlation has been found between Δ f H m o (RONa)andΔ f H m o (ROH) for R=n-alkyl, enabling the prediction of data for other sodium alkoxides

  18. Multinuclear solid-state high-resolution and C-13 -{Al-27} double-resonance magic-angle spinning NMR studies on aluminum alkoxides

    NARCIS (Netherlands)

    Abraham, A.; Prins, R.; Bokhoven, J.A. van; Eck, E.R.H. van; Kentgens, A.P.M.

    2006-01-01

    A combination of Al-27 magic-angle spinning (MAS)/multiple quantum (MQ)-MAS, C-13-H-1 CPMAS, and C-13-{Al-27} transfer of population in double-resonance (TRAPDOR) nuclear magnetic resonance (NMR) were used for the structural elucidation of the aluminum alkoxides aluminum ethoxide, aluminum

  19. IONOTHERMAL SYNTHESIS, STRUCTURES AND SUPRAMOLE

    African Journals Online (AJOL)

    Preferred Customer

    2Department of Chemistry, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal. (Received October 14 ... The principal feature of ionothermal synthesis is that the ionic liquids (ILs) act as both the “designed” green solvents ... purification except [EMI]Br. [EMI]Br was synthesized from the reaction of ethylbromide with.

  20. Alkoxide-based magnesium electrolyte compositions for magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng; Sun, Xiao-Guang; Liao, Chen; Guo, Bingkun

    2018-01-30

    Alkoxide magnesium halide compounds having the formula: RO--Mg--X (1) wherein R is a saturated or unsaturated hydrocarbon group that is unsubstituted, or alternatively, substituted with one or more heteroatom linkers and/or one or more heteroatom-containing groups comprising at least one heteroatom selected from fluorine, nitrogen, oxygen, sulfur, and silicon; and X is a halide atom. Also described are electrolyte compositions containing a compound of Formula (1) in a suitable polar aprotic or ionic solvent, as well as magnesium batteries in which such electrolytes are incorporated.

  1. Structured synthesis of MEMS using evolutionary approaches

    DEFF Research Database (Denmark)

    Fan, Zhun; Wang, Jiachuan; Achiche, Sofiane

    2008-01-01

    In this paper, we discuss the hierarchy that is involved in a typical MEMS design and how evolutionary approaches can be used to automate the hierarchical synthesis process for MEMS. The paper first introduces the flow of a structured MEMS design process and emphasizes that system-level lumped...... the integrated design automation idea using these evolutionary approaches....

  2. Synthesis, spectroscopy and supramolecular structures of two ...

    Indian Academy of Sciences (India)

    TECS

    2007-05-16

    May 16, 2007 ... Indian Academy of Sciences. 243. #. Dedicated to Prof. Dr. Werner Weisweiler on the occasion of his 69th birthday. *For correspondence. Synthesis, spectroscopy and supramolecular structures of two magnesium 4-nitrobenzoate complexes. #. BIKSHANDARKOIL R SRINIVASAN,. 1,. * JYOTI V SAWANT,.

  3. Hydrothermal synthesis, crystal structure and luminescence property ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 12. Hydrothermal synthesis, crystal structure and luminescence property of a three dimensional Sm(III) coordination polymer with 2,5-pyridinedicarboxylic acid. Kranthi Kumar Gangu Anima S Dadhich Saratchandra Babu Mukkamala. Volume 127 Issue 12 ...

  4. Synthesis, crystal structure, thermal analysis and dielectric

    Indian Academy of Sciences (India)

    Annual Meetings · Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 5. Synthesis, crystal structure, thermal analysis and dielectric properties of two mixed trichlorocadmiates (II).

  5. Synthesis, properties and supramolecular structure of ...

    Indian Academy of Sciences (India)

    Synthesis, properties and supramolecular structure of piperazinediium thiosulfate monohydrate. +. BIKSHANDARKOIL R SRINIVASANa*, ASHISH R NAIKa. , SUNDER N DHURIa. ,. CHRISTIAN NÄTHERb and WOLFGANG BENSCHb. aDepartment of Chemistry, Goa University, Goa 403 206, India. bInstitut für ...

  6. Synthesis and structures of metal chalcogenide precursors

    Science.gov (United States)

    Hepp, Aloysius F.; Duraj, Stan A.; Eckles, William E.; Andras, Maria T.

    1990-01-01

    The reactivity of early transition metal sandwich complexes with sulfur-rich molecules such as dithiocarboxylic acids was studied. Researchers recently initiated work on precursors to CuInSe2 and related chalcopyrite semiconductors. Th every high radiation tolerance and the high absorption coefficient of CuInSe2 makes this material extremely attractive for lightweight space solar cells. Their general approach in early transition metal chemistry, the reaction of low-valent metal complexes or metal powders with sulfur and selenium rich compounds, was extended to the synthesis of chalcopyrite precursors. Here, the researchers describe synthesis, structures, and and routes to single molecule precursors to metal chalcogenides.

  7. SYNTHESIS, CHARACTERIZATION AND CRYSTAL STRUCTURES ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    The V atoms in the complexes are in octahedral coordination. Thermal stabilities of the complexes have also been studied. KEY WORDS: Oxovanadium complex, Aroylhydrazone ligand, Crystal structure, X-ray diffraction, Thermal property. INTRODUCTION. Coordination chemistry of vanadium has attracted considerable ...

  8. SYNTHESIS, CHARACTERIZATION AND CRYSTAL STRUCTURE ...

    African Journals Online (AJOL)

    Preferred Customer

    Cg1, Cg2 and Cg3 are the centroids of Mo1-O2-C8-N2-N1, C9-C14 and. C1-C6 benzene rings. Figure 1. Molecular structure of the complex at 30% probability displacement. IR spectra. The hydrazone ligands showed stretching bands attributed to C=O, C=N, C–OH and NH at. 1656, 1637, 1155 and 1237, and 3211 cm–1, ...

  9. Alcohol-free alkoxide process for containing nuclear waste

    Science.gov (United States)

    Pope, James M.; Lahoda, Edward J.

    1984-01-01

    Disclosed is a method of containing nuclear waste. A composition is first prepared of about 25 to about 80%, calculated as SiO.sub.2, of a partially hydrolyzed silicon compound, up to about 30%, calculated as metal oxide, of a partially hydrolyzed aluminum or calcium compound, about 5 to about 20%, calculated as metal oxide, of a partially hydrolyzed boron or calcium compound, about 3 to about 25%, calculated as metal oxide, of a partially hydrolyzed sodium, potassium or lithium compound, an alcohol in a weight ratio to hydrolyzed alkoxide of about 1.5 to about 3% and sufficient water to remove at least 99% of the alcohol as an azeotrope. The azeotrope is boiled off and up to about 40%, based on solids in the product, of the nuclear waste, is mixed into the composition. The mixture is evaporated to about 25 to about 45% solids and is melted and cooled.

  10. Synthesis, structural and electrical characterizations of thermally ...

    African Journals Online (AJOL)

    Synthesis, structural and electrical characterizations of thermally evaporated Cu 2 SnS 3 thin films. ... The surface profilometer shows that the deposited films are rough. The XRD spectra identified the ... The electrical resistivity of the deposited Cu2SnS3 film is 2.55 x 10-3 Ωcm. The conductivity is in the order of 103 Ω-1cm-1.

  11. Marine Nucleosides: Structure, Bioactivity, Synthesis and Biosynthesis

    Directory of Open Access Journals (Sweden)

    Ri-Ming Huang

    2014-12-01

    Full Text Available Nucleosides are glycosylamines that structurally form part of nucleotide molecules, the building block of DNA and RNA. Both nucleosides and nucleotides are vital components of all living cells and involved in several key biological processes. Some of these nucleosides have been obtained from a variety of marine resources. Because of the biological importance of these compounds, this review covers 68 marine originated nucleosides and their synthetic analogs published up to June 2014. The review will focus on the structures, bioactivities, synthesis and biosynthetic processes of these compounds.

  12. Structure, bioactivity, and synthesis of methylated flavonoids.

    Science.gov (United States)

    Wen, Lingrong; Jiang, Yueming; Yang, Jiali; Zhao, Yupeng; Tian, Miaomiao; Yang, Bao

    2017-06-01

    Methylated flavonoids are an important type of natural flavonoid derivative with potentially multiple health benefits; among other things, they have improved bioavailability compared with flavonoid precursors. Flavonoids have been documented to have broad bioactivities, such as anticancer, immunomodulation, and antioxidant activities, that can be elevated, to a certain extent, by methylation. Understanding the structure, bioactivity, and bioavailability of methylated flavonoids, therefore, is an interesting topic with broad potential applications. Though methylated flavonoids are widely present in plants, their levels are usually low. Because developing efficient techniques to produce these chemicals would likely be beneficial, we provide an overview of their chemical and biological synthesis. © 2017 New York Academy of Sciences.

  13. Synthesis of Structures Related to Antifreeze Glycoproteins

    OpenAIRE

    Fyrner, Timmy

    2005-01-01

    In this thesis, synthesis of structures related to antifreeze glycoproteins (AFGPs) are presented. Synthetic routes to a protected carbohydrate derivative, 2,3,4,6-tetra-O-benzyl-β-galactopyranosyl-(1→3)-2-deoxy-2-azido-4,6-di-O-benzyl-β-D-thio-1-galactopyranoside, and a tBu-Ala-Thr-Ala-Fmoc tripeptide, are described. These compounds are meant to be used in the assembly of AFGPs and analogues thereof. A Gal-GlcN disaccharide was synthesized via glycosylation between the donor, bromo-2-O-benzo...

  14. Wall grid structure for interior scene synthesis

    KAUST Repository

    Xu, Wenzhuo

    2015-02-01

    We present a system for automatically synthesizing a diverse set of semantically valid, and well-arranged 3D interior scenes for a given empty room shape. Unlike existing work on layout synthesis, that typically knows potentially needed 3D models and optimizes their location through cost functions, our technique performs the retrieval and placement of 3D models by discovering the relationships between the room space and the models\\' categories. This is enabled by a new analytical structure, called Wall Grid Structure, which jointly considers the categories and locations of 3D models. Our technique greatly reduces the amount of user intervention and provides users with suggestions and inspirations. We demonstrate the applicability of our approach on three types of scenarios: conference rooms, living rooms and bedrooms.

  15. Thermochromic behavior of vanadium(IV) alkoxides in solution: a molecular modeling approach

    International Nuclear Information System (INIS)

    Freitas, Alexandre C. de; Westrup, Katia C. M.; Nunes, Giovana G.; Gulin, Denis J.; Haiduke, Roberto L. A.; Soares, Jaisa F.; Sa, Eduardo L. de

    2010-01-01

    The thermochromic behavior exhibited by vanadium(IV) alkoxides, [V 2 (mu-OPr i ) 2 (OPr i ) 6 ] and [V 2 (m-ONep) 2 (ONep) 6 ], OPr i = isopropoxide and ONep = neopentoxide, was studied by molecular modeling using DFT, TDDFT and INDO/S methods. The vibrational and electronic spectra calculated for [V 2 (mu-OPr i ) 2 (OPr i ) 6 ] were very similar to the experimental data registered for crystalline samples of the complex and for its solutions at low temperature ( 315 K) were compatible with those calculated for the monomeric form, [V(OPr i ) 4 ]. These results consistently point to a monomer/dimer equilibrium as an explanation for the solution thermochromism of {V(OPr i )-4} n . In spite of the structural similarity between [V 2 (mu-ONep) 2 (ONep) 6 ] and [V 2 (mu-OPr i ) 2 (OPr i ) 6 ] in the solid state, the thermochromic behavior of the former could not be explained by the same model, and the possibility of tetranuclear aggregation at low temperatures was also investigated. (author)

  16. New Hybrid Route to Biomimetic Synthesis

    National Research Council Canada - National Science Library

    Morse, Daniel

    2003-01-01

    ... for the structure-directing polymerization of titanium dioxide from the appropriate water-stable alkoxide precursor. This result dramatically extends our initial development of the new field we called "Silicon Biotechnology" to an even broader "Functional Inorganic Materials Biotechnology."

  17. Synthesis, structures and theoretical investigation of

    Science.gov (United States)

    Weigend; Wirth; Ahlrichs; Fenske

    2000-02-04

    The silylated derivative of thiophosphoric acid (S)P(SSiMe3)3 is used as a convenient starting compound for the synthesis of multinuclear Cu and Au cluster complexes. (S)P(SSiMe3)3 reacts with CuCI/PPh3 and [AuCClPPh3] to give the following compounds: [Cu4(P2S6)(PPh3)4] (1), [Cu6(P2S6)Cl2-(PPh3)6] (2) and [Au4(P2S6)(PPh3)4](3). According to X-ray structure determination, these compounds contain P2S6(4-) ions, in which S atoms act as ligands for Cu+ and Au+ ions. Although 1 and 3 have the same stoichiometry, bonding of the metal ions to the P2S6 skeleton displays small but remarkable differences. Au is twofold coordinated, whereas Cu shows a threefold coordination. Ab initio calculations have been carried out to rationalise these structural differences. The theoretical treatment of the corresponding Ag compound indicates the latter to be less stable.

  18. Silica Synthesis by Sponges: Unanticipated Molecular Mechanism

    Science.gov (United States)

    Morse, D. E.; Weaver, J. C.

    2001-12-01

    Oceanic diatoms, sponges and other organisms synthesize gigatons per year of silica from silicic acid, ultimately obtained from the weathering of rock. This biogenic silica exhibits a remarkable diversity of structures, many of which reveal a precision of nanoarchitectural control that exceeds the capabilities of human engineering. In contrast to the conditions of anthropogenic and industrial manufacture, the biological synthesis of silica occurs under mild physiological conditions of low temperatures and pressures and near-neutral pH. In addition to the differentiation between biological and abiotic processes governing silica formation, the biomolecular mechanisms controlling synthesis of these materials may offer insights for the development of new, environmentally benign routes for synthesis of nanostructurally controlled silicas and high-performance polysiloxane composites. We found that the needle-like silica spicules made by the marine sponge, Tethya aurantia, each contain an occluded axial filament of protein composed predominantly of repeating assemblies of three similar subunits we named "silicateins." To our surprise, analysis of the purified protein subunits and the cloned silicatein DNAs revealed that the silicateins are highly homologous to a family of hydrolytic enzymes. As predicted from this finding, we discovered that the silicatein filaments are more than simple, passive templates; they actively catalyze and spatially direct polycondensation to form silica, (as well as the phenyl- and methyl-silsesquioxane) from the corresponding silicon alkoxides at neutral pH and low temperature. Catalytic activity also is exhibited by the silicatein subunits obtained by disaggregation of the protein filaments and those produced from recombinant DNA templates cloned in bacteria. This catalytic activity accelerates the rate-limiting hydrolysis of the silicon alkoxide precursors. Genetic engineering, used to produce variants of the silicatein molecule with

  19. Drug Development of the Antimalarial Agent Artemisinin: Total Synthesis, Analog Synthesis, and Structure-Activity Relationship Studies

    Science.gov (United States)

    1990-08-15

    jHoluenesulfonyl hydrazide in tetrahydrofuran (THF), solvolysis of the ketal group and subsequent hydrazone formation was observed. Under base...ARTEMISININ: TOTAL SYNTHESIS , ANALOG SYNTHESIS , AND STRUCTURE-ACTIVITY RELATIONSHIP STUDIES mc Mitchell A. Avery, Ph.D. SRI International...Antimalarial Agent Artemisinin: Total Synthesis , Analog Synthesis and Structure-Activity Relationship Studies 12 PERSONAL AUTHOR(S) Mitchell A

  20. Synthesis, structure and low temperature study of electric transport ...

    Indian Academy of Sciences (India)

    Synthesis, structure and low temperature study of electric transport and magnetic properties of GdSr2MnCrO7. Devinder ... Keywords. Chemical synthesis; X-ray diffraction; electrical properties; magnetic properties. Abstract. The layered perovskite oxide, GdSr2MnCrO7, has been prepared by the standard ceramic method.

  1. Halogenated Symmetrical Tetraazapentacenes: Synthesis, Structures, and Properties.

    Science.gov (United States)

    Engelhart, Jens U; Paulus, Fabian; Schaffroth, Manuel; Vasilenko, Vladislav; Tverskoy, Olena; Rominger, Frank; Bunz, Uwe H F

    2016-02-05

    We herein describe the synthesis and property evaluation of several brominated and chlorinated tetraazapentacenes. The targets were obtained by thermal condensation of 2,5-dihydroxyquinone with 4,5-dichloro-, 2,6-dichloro-, and 4,5-dibromo-1,2-phenylenediamine, followed by oxidation with hot acidic dichromate. Double alkynylation, reductive deoxygenation, and subsequent oxidation using MnO2 furnishes the target compounds. Absorption spectra, electrochemistry, and single crystal structures of the targets are reported. The 1,4,8,11-tetrachlorotetraazapentacene (1,4,8,11-tetrachloroquinoxalino[2,3-b]phenazine) carrying its chlorine atoms in the peri-positions packs in a herringbone type arrangement, while the isomer (2,3,9,10-tetrachloroquinoxalino[2,3-b]phenazine, with the chlorine atoms in the east and west positions) packs in one-dimensional stacks. In all cases, the reduction potentials and the calculated LUMO-positions are decreased by the introduction of the halogen atoms.

  2. Organoactinide chemistry: synthesis, structure, and solution dynamics

    International Nuclear Information System (INIS)

    Brennan, J.G.

    1985-12-01

    This thesis considers three aspects of organoactinide chemistry. In chapter one, a bidentate phosphine ligand was used to kinetically stabilize complexes of the type Cp 2 MX 2 . Ligand redistribution processes are present throughout the synthetic work, as has often been observed in uranium cyclopentadienyl chemistry. The effects of covalent M-L bonding on the solution and solid state properties of U(III) coordination complexes are considered. In particular, the nature of the more subtle interaction between the metal and the neutral ligand are examined. Using relative basicity data obtained in solution, and solid state structural data (and supplemented by gas phase photoelectron measurements), it is demonstrated that the more electron rich U(III) centers engage in significant U → L π-donation. Trivalent uranium is shown to be capable of acting either as a one- or two-electron reducing agent toward a wide variety of unsaturated organic and inorganic molecules, generating molecular classes unobtainable via traditional synthetic approaches, as well as offering an alternative synthetic approach to molecules accessible via metathesis reactions. Ligand redistribution processes are again observed, but given the information concerning ligand lability, this reactivity pattern is applied to the synthesis of pure materials inaccessible from redox chemistry. 214 refs., 33 figs., 10 tabs

  3. Hydrolytic activity of μ-alkoxide/acetato-bridged binuclear Cu(II ...

    Indian Academy of Sciences (India)

    Abstract. Two μ-alkoxide/acetate-bridged small molecule binuclear copper(II) complexes were synthesized, and used to promote the hydrolysis of a classic carboxylic acid ester, p-nitrophenyl picolinate (PNPP). Both binuclear complexes exhibited good hydrolytic reactivity, giving rise to ca. 15547- and 17462-fold ...

  4. Synthesis and crystal structure of a wheel-shaped supramolecular ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 5. Synthesis and crystal structure of a wheel-shaped supramolecular coordination complex. Deepak Gupta Palanisamy Rajakannu Bhaskaran Shankar Firasat Hussain Malaichamy Sathiyendiran. Special issue on Chemical Crystallography Volume 126 ...

  5. Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

    Science.gov (United States)

    Kim, Young-Soon; Lee, Yu-Ri; Kim, Byeong-Joo; Lee, Jae-Hun; Moon, Seung-Hyun; Lee, Hunju

    2015-01-01

    Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y2O3 dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50 nm to ∼1 nm over a 10 × 10 μm2 area. After Y2O3 deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO3 (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y2O3 and GdBCO/LMO/MgO/Y2O3 stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y2O3 multilayer structure varied from 190 to 420 A/cm with different solutions, when measured at 77 K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

  6. Ionothermal synthesis and structural characterization of [Cu ...

    Indian Academy of Sciences (India)

    bSchool of Chemistry and Chemical Engineering, Harbin Normal University, No. 1 Shida Road Limin development Zone, Harbin 150025, P. R. China e-mail: caiqinghai@yahoo.com. MS received 29 December 2014; revised 2 April 2015; accepted 3 April 2015. Abstract. The ionothermal synthesis and spectroscopic, thermal ...

  7. Superheavy nuclei – cold synthesis and structure

    Indian Academy of Sciences (India)

    Abstract. The quantum mechanical fragmentation theory (QMFT), given for the cold synthesis of new and superheavy elements, is reviewed and the use of radioactive nuclear beams (RNB) and targets (RNT) is discussed. The QMFT is a complete theory of cold nuclear phenomena, namely, the cold fission, cold fusion and ...

  8. Superheavy nuclei–cold synthesis and structure

    Indian Academy of Sciences (India)

    The quantum mechanical fragmentation theory (QMFT), given for the cold synthesis of new and superheavy elements, is reviewed and the use of radioactive nuclear beams (RNB) and targets (RNT) is discussed. The QMFT is a complete theory of cold nuclear phenomena, namely, the cold fission, cold fusion and cluster ...

  9. Effect of Ligand Field Tuning on the SMM Behavior for Three Related Alkoxide-Bridged Dysprosium Dimers.

    Science.gov (United States)

    Peng, Yan; Mereacre, Valeriu; Baniodeh, Amer; Lan, Yanhua; Schlageter, Martin; Kostakis, George E; Powell, Annie K

    2016-01-04

    The synthesis and characterization of three Dy2 compounds, [Dy2(HL1)2(NO3)4] (1), [Dy2(L2)2(NO3)4] (2), and [Dy2(HL3)2(NO3)4] (3), formed using related tripodal ligands with a central tertiary amine bearing picolyl and alkoxy arms, 2-[(2-hydroxy-ethyl)-pyridin-2-ylmethylamino]-ethanol (H2L1), 2-(bis-pyridin-2-ylmethylamino)-ethanol (HL2), and 2-(bis-pyridin-2-ylmethylamino)-propane-1,3-diol (H2L3), are reported. The compounds are rare examples of alkoxide-bridged {Dy2} complexes and display capped square antiprism coordination geometry around each Dy(III) ion. Changes in the ligand field environment around the Dy(III) ions brought about through variations in the ligand donors can be gauged from the magnetic properties, with compounds 1 and 2 showing antiparallel coupling between the Dy(III) ions and 3 showing parallel coupling. Furthermore, slow relaxation of the magnetization typical of SMM behavior could be observed for compounds 2 and 3, suggesting that small variations in the ligand field can have a significant influence on the slow relaxation processes responsible for SMM behavior of Dy(III)-based systems.

  10. Preparation of titanium diboride powders from titanium alkoxide and ...

    Indian Academy of Sciences (India)

    Titanium diboride powders were prepared through a sol–gel and boron carbide reduction route by using TTIP and B4C as titanium and boron sources. The influence of TTIP concentration, reaction temperature and molar ratio of precursors on the synthesis of titanium diboride was investigated. Three different concentrations ...

  11. Preparation of titanium diboride powders from titanium alkoxide and ...

    Indian Academy of Sciences (India)

    Administrator

    1⋅3 to 2⋅5. The results indicated that as the TTIP concentration had an important role in gel formation, the reaction temperature and B4C to TTIP molar ratio showed obvious effects on the formation of TiB2. Pure. TiB2 was prepared using molar composition of Ti : B4C = 1 : 2⋅3 and the optimum synthesis temperature was.

  12. The preparation of lithium aluminate by the hydrolysis of lithium and aluminum alkoxides

    International Nuclear Information System (INIS)

    Turner, C.W.; Clatworthy, B.C.; Gin, A.Y.H.

    1987-10-01

    Lithium aluminate was prepared by heating the hydrolysis products from various combinations of lithium and aluminum alkoxides under an atmosphere of nitrogen. The product was β-LiA1O 2 when aluminum iso-propoxide was a starting material, whereas γ-LiA1O 2 was the product for preparations starting with aluminum n-butoxide. The results were independent of the choice of lithium alkoxide. The hydrolysis of aluminum sec-butoxide with a solution of LiOH led to the γ phase as well. The temperature at which the γ phase developed depended upon the conditions of the hydrolysis reaction and was observed at a temperature as low as 550 degrees Celcius

  13. Hydrothermal synthesis, structure and characterization of new ...

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Hydrothermal; crystal structure; solid electrolyte; iron (III) pyrophosphate. 1. Introduction ... tion, structure and electrical conductivity and the higher values of ..... type cavity structure. Acknowledgements. The authors would like to express their thanks to DST,. New Delhi, for financial assistance under the projects.

  14. Chlorosulfolipids: Structure, synthesis, and biological relevance

    OpenAIRE

    Bedke, D. Karl; Vanderwal, Christopher D.

    2010-01-01

    Chlorosulfolipids have been isolated from freshwater algae and from toxic mussels. They appear to have a structural role in algal membranes and have been implicated in Diarrhetic Shellfish Poisoning. Further fascinating aspects of these compounds include their stereochemically complex polychlorinated structures and the resulting strong conformational biases, and their poorly understood (yet surely compelling) biosynthesis. Discussions of each of these topics and of efforts in structural and s...

  15. Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Soon, E-mail: kyscjb@i-sunam.com; Lee, Yu-Ri; Kim, Byeong-Joo; Lee, Jae-Hun; Moon, Seung-Hyun; Lee, Hunju

    2015-01-15

    Highlights: • Economical method for crack-free amorphous yttria layer deposition by dip coating. • Simpler process for planar yttria film as a diffusion barrier and nucleation layer. • Easy control over the film properties with better characteristics. • Easy control over the thickness of the deposited films. • A feasible process that can be easily adopted by HTSCC industries. - Abstract: Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y{sub 2}O{sub 3} dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50 nm to ∼1 nm over a 10 × 10 μm{sup 2} area. After Y{sub 2}O{sub 3} deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO{sub 3} (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y{sub 2}O{sub 3} and GdBCO/LMO/MgO/Y{sub 2}O{sub 3} stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y{sub 2}O{sub 3} multilayer structure varied from 190 to 420 A/cm with different solutions, when measured at 77 K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

  16. Synthesis, structure, redox and spectra of green iridium complexes ...

    Indian Academy of Sciences (India)

    TECS

    3. *For correspondence. Synthesis, structure, redox and spectra of green iridium complexes of tridentate azo-aromatic ligands. MANASHI PANDA,a CHAYAN DAS,a CHEN-HSIUNG HUNGb and. SREEBRATA ... Mn(II)7 and Fe(II)8 but also produces stable anionic ..... the EPR of the oxidized complexes were not suc- cessful ...

  17. Synthesis and structure refinement of layered double hydroxides of ...

    Indian Academy of Sciences (India)

    Administrator

    )-oxygen bond in this compound as opposed to the Co–Ga hydroxide. These observations are supported by IR spectra. Keywords. Layered double hydroxide; Rietveld refinement; urea hydrolysis. 1. Introduction. The synthesis, structure and properties of layered double hydroxides (LDHs) have been widely studied in recent.

  18. Abstract: Synthesis, structure and density functional theory (DFT ...

    Indian Academy of Sciences (India)

    Ruthenium Complexes of Chelating Amido-functionalized N-heterocyclic Carbene Ligands: Synthesis, Structure and DFT Studies. Sachin Kumar,† Anantha Narayanan,† Mitta Nageswar Rao,† Mobin M. Shaikh§ and Prasenjit Ghosh*,†. †Department of Chemistry and. §National Single Crystal X-ray Diffraction Facility,.

  19. Synthesis, structure and applications of [cis-dioxomolybdenum (VI ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 123; Issue 2. Synthesis, structure and applications of [cis-dioxomolybdenum(VI)-(ONO)] type complexes. Rajan Deepan Chakravarthy Dillip Kumar Chand. Volume 123 Issue 2 March 2011 pp 187-199 ... http://www.ias.ac.in/article/fulltext/jcsc/123/02/0187-0199 ...

  20. Synthesis, crystal structure and catecholase activity of a Ni (II ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 6. Synthesis, crystal structure and catecholase activity of a Ni(II) complex derived from a tetradentate Schiff base ligand. Pradipta Kumar Basu Merry Mitra Amrita Ghosh Latibuddin Thander Chia -Her Lin Rajarshi Ghosh. Rapid Communications Volume 126 ...

  1. Synthesis, characterization, X-ray crystal structure, electrochemical ...

    Indian Academy of Sciences (India)

    DOI 10.1007/s12039-015-0978-8. Synthesis, characterization, X-ray crystal structure, electrochemical evaluation and anti-cancer studies of a mixed ligand Cu(II) complex of (E)-N -((2-hydroxynaphthalen-1-yl)methylene)acetohydrazide. IRAN SHEIKHSHOAIEa, S YOUSEF EBRAHIMIPOURa,∗, MAHDIEH SHEIKHSHOAIEa,.

  2. Synthesis, structure and applications of [cis-dioxomolybdenum (VI ...

    Indian Academy of Sciences (India)

    Oxo-molybdenum chemistry is of great interest since such units are found in the active sites of a majority of molybdo-enzymes. In order to mimic the biological systems, a number of oxo-molybdenum complexes have been synthesised and studied. This review describes synthesis, structure and applications of ...

  3. Synthesis, structure and luminescence properties of phosphates A1 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 1. Synthesis, structure and luminescence properties of phosphates A 1 − 3 x Eu x Zr 2 (PO 4 ) 3 (A—alkali metal). ANTON KANUNOV BENOIT GLORIEUX ALBINA ORLOVA ELENA BOROVIKOVA GALINA ZAVEDEEVA. Volume 40 Issue 1 February 2017 pp 7- ...

  4. Synthesis and crystal structure of a wheel-shaped supramolecular ...

    Indian Academy of Sciences (India)

    Synthesis and crystal structure of a wheel-shaped supramolecular coordination complex. DEEPAK GUPTA, PALANISAMY RAJAKANNU, BHASKARAN SHANKAR,. FIRASAT HUSSAIN and MALAICHAMY SATHIYENDIRAN. ∗. Department of Chemistry, University of Delhi, Delhi 110 007, India e-mail: mvdiran@yahoo.com; ...

  5. Synthesis, crystal structure, thermal analysis and dielectric ...

    Indian Academy of Sciences (India)

    In both the materials, the crystal structure has been determined by X-ray single crystal analysis at room temperature (293 K). The compound structures consist of K + (or NH 4 + ) cations and double chains of CdCl 6 octahedra sharing one edge extending along b -axis. The mixture of KA + /NH 4 + cations are located ...

  6. Hydrothermal synthesis, structure and characterization of new ...

    Indian Academy of Sciences (India)

    Unknown

    The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability. Keywords. Hydrothermal; crystal structure; solid electrolyte; iron (III) pyrophosphate. 1. Introduction. NASICON and related compounds belong to the well known family of solid ...

  7. Synthesis, crystal structures, spectroscopic characterization and in ...

    Indian Academy of Sciences (India)

    Both the complexes were structurally characterized by single crystal XRD. The crystal structure of complex 1 displays a distorted square pyramidal geometry in which Schiff base is coordinated to the Cu(II) ion via ONO-donor in the axial mode, whereas, the chelating diamine displays axial and equatorial mode of binding via ...

  8. Bioinspired synthesis of new silica structures.

    Science.gov (United States)

    Patwardhan, Siddharth V; Mukherjee, Niloy; Steintz-Kannan, Miriam; Clarson, Stephen J

    2003-05-21

    Silicon and oxygen are the two most abundant elements in the Earth's crust but despite the vast scientific literature on crystalline and amorphous silica, new chemistries, structures and applications continue to be discovered for compounds formed from these elements--thus we present here for the first time the formation of new amorphous silica structures that were uniquely synthesized by a bioinspired synthetic system.

  9. Synthesis engineering of iron oxide raspberry-shaped nanostructures.

    Science.gov (United States)

    Gerber, O; Pichon, B P; Ihiawakrim, D; Florea, I; Moldovan, S; Ersen, O; Begin, D; Grenèche, J-M; Lemonnier, S; Barraud, E; Begin-Colin, S

    2017-01-07

    Magnetic porous nanostructures consisting of oriented aggregates of iron oxide nanocrystals display very interesting properties such as a lower oxidation state of magnetite, and enhanced saturation magnetization in comparison with individual nanoparticles of similar sizes and porosity. However, the formation mechanism of these promising nanostructures is not well understood, which hampers the fine tuning of their magnetic properties, for instance by doping them with other elements. Therefore the formation mechanism of porous raspberry shaped nanostructures (RSNs) synthesized by a one-pot polyol solvothermal method has been investigated in detail from the early stages by using a wide panel of characterization techniques, and especially by performing original in situ HR-TEM studies in temperature. A time-resolved study showed the intermediate formation of an amorphous iron alkoxide phase with a plate-like lamellar structure (PLS). Then, the fine investigation of PLS transformation upon heating up to 500 °C confirmed that the synthesis of RSNs involves two iron precursors: the starting one (hydrated iron chlorides) and the in situ formed iron alkoxide precursor which decomposes with time and heating and contributes to the growth step of nanostructures. Such an understanding of the formation mechanism of RSNs is necessary to envision efficient and rational enhancement of their magnetic properties.

  10. Constrained saccharides: a review of structure, biology, and synthesis.

    Science.gov (United States)

    Rodriguez, Jacob; O'Neill, Sloane; Walczak, Maciej A

    2018-03-01

    Review primarily covers from 1995-2018Carbohydrate function, recognized in a multitude of biological processes, provides a precedent for developing carbohydrate surrogates that mimic the structure and function of bioactive compounds. In order to constrain highly flexible oligosaccharides, synthetic tethering techniques like those exemplified by stapled peptides are utilized to varying degrees of success. Naturally occurring constrained carbohydrates, however, exist with noteworthy cytotoxic and chemosensitizing properties. This review highlights the structure, biology, and synthesis of this intriguing class of molecules.

  11. Synthesis, crystal structure, theoretical study and luminescence ...

    Indian Academy of Sciences (India)

    phenanthroline) has been synthesized and characterized by elemental analysis, infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray single crystal analysis and fluorescent analysis. Its crystal structure is monoclinic with space group 2/ and ...

  12. Synthesis and structure of cerium nitrosocarbonylcyanmethanid complex

    International Nuclear Information System (INIS)

    Gerasimenko, H.; Scopenko, V.V.; Kapshuk, A.A.

    1998-01-01

    Full text: The complex compound [CeL 4 Dy 2 ]Na*2Ac (where L- nitrosocarbonylcyanmethanid, Dy -- dipyridile, Ac - acetone) were synthesised by interaction of cerium chloride and sodium nitrosocarbonylcyanmethanid from acetone solution. After two hours of mixing the dipyridil solution in acetone was added for complex stabilization. After filtration solution was put to desiccator for crystallisation. The complex was studied using IR- and UV-spectroscopy. The structure of the complex was determined using X-ray structure analysis. It was found that the structure of the complex belongs to orthorhombic Pna2(1) syngony with the unit cell parameters 17.010, 16.280 and 16.340Angstroms, respectively. It was found that cerium in the compound was eight co-ordinated. Four nitroso ligands were co-ordinated by bidentate bridge method and two dipyridiles by bidentate-cycle method

  13. EXAFS and FTIR studies of selenite and selenate sorption by alkoxide-free sol–gel generated Mg–Al–CO 3 layered double hydroxide with very labile interlayer anions

    KAUST Repository

    Chubar, Natalia

    2014-08-08

    © the Partner Organisations 2014. Current research on Layered Double Hydroxides (LDHs, also known as hydrotalcites, HTs) is predominantly focused on their intercalations, but the industrial application of LDHs for anion exchange adsorption has not yet been achieved. It was recently recognized that, to develop LDH applications, these materials should be produced using methods other than direct co-precipitation. Mg-Al-CO3LDH produced using an alkoxide-free sol-gel synthesis showed exceptional removal properties for aqueous selenium species. Se K-edge EXAFS/XANES and FTIR studies (supporting the data by XRD patterns) were performed to explain the unusual adsorptive performance of Mg-Al LDH by revealing the molecular-level mechanism of HSeO3 -, SeO4 2-and {HSeO3 -+ SeO4 2-} uptake at pH 5, 7 and 8.5. The role of inner-sphere complexation (exhibited by inorganic adsorbents with good performance) in adsorption of both selenium aqueous species was not confirmed. However, Mg-Al LDH fully met the other expectations regarding the involvement of the interlayer anions. The interlayer carbonate (due to its favorable speciation and generous HT hydration) gave a "second breath" to selenite sorption and was the only mechanism that controlled the removal of Se(vi). Because inner sphere complexation was the leading mechanism for selenite removal, ion exchange via surface OH-and interlayer CO3 2-species was the only mechanism for selenate removal; both of these species were easily bound to Mg-Al LDH (on its surface and gently parked into the interlayer forming a multilayer without violation of the structure of Mg-Al-CO3LDH). This work provides the first theoretical explanation of why it is more difficult to sorb selenate than selenite and which material should be used for this purpose. This journal is

  14. Synthesis, characterization and crystal structure of a ...

    African Journals Online (AJOL)

    The Mo atom in the complex is in octahedral coordination. Thermal stability of the complex has also been studied. KEY WORDS: Molybdenum complex, Hydrazone ligand, Crystal structure, X-ray diffraction, Thermal property. Bull. Chem. Soc. Ethiop. 2014, 28(3), 409-414. DOI: http://dx.doi.org/10.4314/bcse.v28i3.10 ...

  15. Synthesis, molecular structure, spectroscopic investigations and ...

    Indian Academy of Sciences (India)

    MS received 29 December 2015; revised 9 April 2016; accepted 25 May 2016 ... B, open form blue. Scheme 1. Structures and Photochromic reaction of the title compound. 2. Experimental. 2.1 Materials and measurements. The mid-IR spectra were obtained in the ... segment is put between two parallel Au(111) surfaces,.

  16. Synthesis, crystal structure, thermal analysis and dielectric ...

    Indian Academy of Sciences (India)

    [13] Perry C H and Lowdes R P 1969 J. Chem. Phys. 51 3648. [14] Sheldrick G M 1997 SHELXS9, Program for the Refinement of Crystal Structures (Germany: University of Gottingen). [15] Loukil M, Kabadou A, Salles Ph and Ben Salah A 2004 Chem. Phys. 300 247. [16] Rolies M M and De Ranter C J 1978 Acta Crystallogr.

  17. Synthesis, crystal structure, theoretical study and luminescence ...

    Indian Academy of Sciences (India)

    performed on complex 1 to rationalize its experimental absorption spectra. Complex 1 exhibits luminescence in EtOH ... potential applications in biological systems like, devel- opment of structural and functional models for ... to react with [WOnS4−n] (n = 0-2).11,12 These reactions result in the formation of a large number of ...

  18. Quantifying the Sigma and Pi interactions between U(V) f orbitals and halide, alkyl, alkoxide, amide and ketimide ligands

    Energy Technology Data Exchange (ETDEWEB)

    University of California, Berkeley; Lukens, Wayne W.; Edelstein, Norman M.; Magnani, Nicola; Hayton, Trevor W.; Fortier, Skye; Seaman, Lani A.

    2013-06-20

    f Orbital bonding in actinide and lanthanide complexes is critical to their behavior in a variety of areas from separations to magnetic properties. Octahedral f1 hexahalide complexes have been extensively used to study f orbital bonding due to their simple electronic structure and extensive spectroscopic characterization. The recent expansion of this family to include alkyl, alkoxide, amide, and ketimide ligands presents the opportunity to extend this study to a wider variety of ligands. To better understand f orbital bonding in these complexes, the existing molecular orbital (MO) model was refined to include the effect of covalency on spin orbit coupling in addition to its effect on orbital angular momentum (orbital reduction). The new MO model as well as the existing MO model and the crystal field (CF) model were applied to the octahedral f1 complexes to determine the covalency and strengths of the ? and ? bonds formed by the f orbitals. When covalency is significant, MO models more precisely determined the strengths of the bonds derived from the f orbitals; however, when covalency was small, the CF model was better than either MO model. The covalency determined using the new MO model is in better agreement with both experiment and theory than that predicted by the existing MO model. The results emphasize the role played by the orbital energy in determining the strength and covalency of bonds formed by the f orbitals.

  19. Synthesis, crystal structure, thermal analysis and dielectric ...

    Indian Academy of Sciences (India)

    2.2 X-ray structure determination. Two transparent parallelepipedic crystals with dimensions,. 0.20 × 0.12 × 0.04 and 0.26 × 0.14 × 0.12, were chosen from the preparation. The intensity data were collected on. An APEX II diffractometer with graphite–crystal monochro- mated MoKα radiation (0.71073 Å). Lorentz and polariz-.

  20. Synthesis and structure of vanillin azomethines

    Directory of Open Access Journals (Sweden)

    Jasmina M. Jovanović

    2009-10-01

    Full Text Available Vanillin is most prominent as the principal flavor and aroma compound in vanilla. Vanillin has been used as a chemical intermediate in the production of pharmaceuticals and other fine chemicals.The two intermediates, assigned as intermediates I and II, were prepared by using vanillin and 1-butylbromide or 2-chloroacetic acid, respectively. The condensation of intermediates with 2,3- -diaminopyridine gave azomethines. Their structure was established by using elemental microanalysis, as well as UV/Vis, FTIR and 1H-NMR spectra. Synthesized compounds were tested for their antifungal activity against Candida albicans, Candida lipolytica and Sacharomyces cerevisiae.

  1. Preparation and characterization of uranium alkoxides through oxidation of uranium metal

    International Nuclear Information System (INIS)

    Gordon, P.L.; Sauer, N.N.; Burns, C.J.; Watkin, J.G.; Van Der Sluys, W.G.

    1993-01-01

    Currently the authors are investigating the preparation of halide-containing uranium alkoxides by simultaneous halogen and alcohol oxidation of uranium metal. They recently reported the formation of U 2 I 4 (O-i-Pr) 4 (HO-i-Pr) 2 which upon addition of excess isopropanol forms UI 2 (O-i-Pr) 2 (HO-i-Pr) 2 . They report further characterization and reactivity for this monomeric species. Attempts to prepare similar complexes are being made using chlorine gas in the presence of other alcohols. They describe this ongoing research

  2. On the hydrolytic stability of organic ligands in Al-, Ti- and Zr-alkoxide complexes

    OpenAIRE

    Hoebbel, Dagobert; Reinert, Thomas; Schmidt, Helmut K.; Arpac, Ertugrul

    1997-01-01

    The complexation degrees of Al-, Ti- and Zr-butoxide (M) with unsaturated and saturated β-diketones (3-allylpentane-2.4-dione-APD, acetylacetone-ACAC) and β-ketoesters (methacryloxyethyl-acetoacetate-MEAA, allylacetoacetate-AAA, ethylacetoacetate-EAA) as organic ligands (L) were examined by IR and 13C NMR spectroscopy and were found to be L : M ≥ 1.5. The hydrolytic stability of the ligands of the metal alkoxide complexes (L : M = 1) during hydrolysis/condensation reactions at th...

  3. Davis-Beirut Reaction: Alkoxide versus Hydroxide Addition to the Key o-Nitrosoimine Intermediate.

    Science.gov (United States)

    Zhu, Jie S; Duong, Matthew R; Teuthorn, Andrew P; Lu, Julia Y; Son, Jung-Ho; Haddadin, Makhluf J; Kurth, Mark J

    2018-03-02

    Reaction options, alkoxide vs hydroxide vs amine addition to the key intermediate (o-nitrosoimine) generated in the Davis-Beirut reaction of an o-nitrobenzylamine substrate, are reported to explain the nucleophilic addition selectivity of this one-pot indazole-forming process. The hydroxide addition/deprotection pathway as well as the fate of the resulting o-nitrosobenzaldehyde were both uncovered with several o-nitrobenzylamine substrates, and design elements required for an efficient double Davis-Beirut reaction, inspired by new mechanistic insights, were defined.

  4. Synthesis, structure, and properties of azatriangulenium salts

    DEFF Research Database (Denmark)

    Laursen, B.W.; Krebs, Frederik C

    2001-01-01

    A general synthetic route to novel nitrogen-bridged heterocyclic carbenium ions of the acridinium and triangulenium type has been developed and investigated. The synthetic method is based on nucleophilic aromatic substitution (SNAr) on the tris(2,6-dimethoxyphenyl)carbenium ion (1) with primary...... amines and, by virtue of its stepwise and irreversible nature, provides a powerful tool for the preparation of a wide variety of new heterocyclic carbenium salts. Several derivatives of the three new oxygen- and/or nitrogen-bridged triangulenium salts, azadioxa- (6), diazaoxa- (7......), and triazatriangulenium (4), have been synthesized and their physicochemical properties have been investigated. Crystal structures for compounds 2 b-PF6: 2d-PF6, 4b-BF4, 4c-BF4, 6e-BF4, and 8 are reported. The different packing modes found for the triazatriagulenium salts are discussed in relation to the electrostatic...

  5. Synthesis, crystal structures, hydrogen bonding graph-sets and ...

    African Journals Online (AJOL)

    Synthesis, crystal structures, hydrogen bonding graph-sets and theoretical studies of nickel (+II) co-ordinations with pyridine-2,6-dicarboxamide oxime. ... which crystallized in the monoclinic space group C2/c with a = 14.915(2), b = 0.895(2), c = 8.205(1) Å, β = 114.69(1), and Z = 4. The complex consists of discrete cations ...

  6. Structure of FD-895 revealed through total synthesis.

    Science.gov (United States)

    Villa, Reymundo; Mandel, Alexander L; Jones, Brian D; La Clair, James J; Burkart, Michael D

    2012-11-02

    The total synthesis of FD-895 was completed through a strategy that featured the use of a tandem esterification ring-closing metathesis (RCM) process to construct the 12-membered macrolide and a modified Stille coupling to append the side chain. These studies combined with detailed analysis of all four possible C16-C17 stereoisomers were used to confirm the structure of FD-895 and identify an analog with an enhanced subnanomolar bioactivity.

  7. Production of dispersed nanometer sized YAG powders from alkoxide, nitrate and chloride precursors and spark plasma sintering to transparency

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, M., E-mail: m.suarez@cinn.e [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Fernandez, A. [Fundacion ITMA, Parque Tecnologico de Asturias, 33428, Llanera (Spain); Menendez, J.L.; Torrecillas, R. [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)

    2010-03-18

    Yttrium aluminum garnet (YAG) was synthesized from different starting materials, i.e., alkoxide, nitrate and chloride precursors. The conversion steps from the precursors to crystalline YAG were studied by Raman spectroscopy. Dispersed YAG powders were formed at a relatively low temperature, around 800 {sup o}C by the chlorides route, whereas alkoxide precursors needed firing over 900 {sup o}C and nitrates even over 1100 {sup o}C. Lyophilized YAG gel was sintered to transparency by the spark plasma sintering method at 1500 {sup o}C with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range.

  8. Production of dispersed nanometer sized YAG powders from alkoxide, nitrate and chloride precursors and spark plasma sintering to transparency

    International Nuclear Information System (INIS)

    Suarez, M.; Fernandez, A.; Menendez, J.L.; Torrecillas, R.

    2010-01-01

    Yttrium aluminum garnet (YAG) was synthesized from different starting materials, i.e., alkoxide, nitrate and chloride precursors. The conversion steps from the precursors to crystalline YAG were studied by Raman spectroscopy. Dispersed YAG powders were formed at a relatively low temperature, around 800 o C by the chlorides route, whereas alkoxide precursors needed firing over 900 o C and nitrates even over 1100 o C. Lyophilized YAG gel was sintered to transparency by the spark plasma sintering method at 1500 o C with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range.

  9. Metal Oxide Nano structures: Synthesis, Properties, and Applications

    International Nuclear Information System (INIS)

    Xu, L. H.; Patil, D. S.; Yang, J.; Xiao, J.

    2015-01-01

    In recent years, nano structured materials have attracted wide attention due to their fascinating optical and electrical properties, which make these materials potentially suitable for applications in electronics, optics, photonics, and sensors. Some metal oxides show a wide variety of morphologies such as nano wires, nano rods, nano tubes, nano rings, and nano belts. Synthesis and investigation of these metal-oxide nano structures are beneficial not only for understanding the fundamental phenomena in low dimensional systems, but also for developing new-generation nano devices with high performance.

  10. Structure, Chemical Synthesis, and Biosynthesis of Prodiginine Natural Products.

    Science.gov (United States)

    Hu, Dennis X; Withall, David M; Challis, Gregory L; Thomson, Regan J

    2016-07-27

    The prodiginine family of bacterial alkaloids is a diverse set of heterocyclic natural products that have likely been known to man since antiquity. In more recent times, these alkaloids have been discovered to span a wide range of chemical structures that possess a number of interesting biological activities. This review provides a comprehensive overview of research undertaken toward the isolation and structural elucidation of the prodiginine family of natural products. Additionally, research toward chemical synthesis of the prodiginine alkaloids over the last several decades is extensively reviewed. Finally, the current, evidence-based understanding of the various biosynthetic pathways employed by bacteria to produce prodiginine alkaloids is summarized.

  11. Characterization structural and morphology ZSM-5 zeolite by hydrothermal synthesis

    International Nuclear Information System (INIS)

    Silva, V.J.; Crispim, A.C.; Queiroz, M.B.; Laborde, H.M.; Rodrigues, M.G.F.; Menezes, R.R.

    2009-01-01

    Solid acids are catalytic materials commonly used in the chemical industry. Among these zeolites are the most important business processes including water treatment, gas separation, and cracking long hydrocarbon chains to produce high octane gasoline. Its synthesis, characterization and applications have been widely studied. The objective this study was to synthesize the ZSM-5 zeolite for future use in separation processes and catalysis. The zeolite ZSM-5 was prepared by hydrothermal synthesis at 170°C, using silica, deionized water and the director of structures (TPABr - tetrapropylammonium bromide). The materials were characterized by X ray diffraction (XRD), scanning electron microscopy (SEM) and semiquantitative chemical analysis by X ray fluorescence (XRF). According to the XRD was possible to observe the formation of ZSM-5 zeolite, with peaks intense and well defined. The SEM showed the formation of individual particles, clean, rounded shapes. (author)

  12. Role of binder in the synthesis of titania membrane

    Indian Academy of Sciences (India)

    The synthesis of titania membrane through sol–gel route involves hydrolysis of alkoxide, peptization of hydrous oxide of titanium to obtain a sol, adjustment of the sol viscosity by including a binder and filtration of the viscous sol through a microporous support, gelation and sintering to desired temperature. The binder plays ...

  13. Synthesis of carbon nano structures by plasma discharge

    International Nuclear Information System (INIS)

    Jimenez L, M.L.

    2007-01-01

    Due to the great quantity of applications of carbon neocarcinostatin (NEC) in diverse areas like: synthesis of super-resistant materials, hydrogen storage, nano sensors generation and nano catalysts, one has seen the necessity to generate new synthesis processes of these materials as well as to already improve those existent. The present work has as objective to optimize the NEC synthesis process by means of the electric arc method which uses alternating current to high frequencies (HF), obtaining relatively clean products; that is to say, it hardly presents amorphous material neither impurities. They stand out the obtaining of carbon nano fibers (NFC) by means of a luminescent-arc discharge, in a gas mixture He-CH 4 with 34% at.Ni/10.32%at.Y like catalyst; to a frequency of 42 k Hz and low power (300 W). This method benefits the agglomeration of the particles in both electrodes due to the high frequencies. The time of duration of the process oscillates between 5 and 20 minutes. The obtained product was characterized by scanning electron microscopy (MEB), transmission electron microscopy (MET) to determine the type of obtained NEC and by X-ray diffraction analysis and Raman spectroscopy to determine the purity of the samples. The NFC are relatively free of amorphous coal. The surface and structural analysis indicates that the fibers have a half diameter of 80 nm. It is also made, a study by optical emission spectroscopy of the plasma using the Swan band to determine the temperature. (Author)

  14. The extended evolutionary synthesis: its structure, assumptions and predictions.

    Science.gov (United States)

    Laland, Kevin N; Uller, Tobias; Feldman, Marcus W; Sterelny, Kim; Müller, Gerd B; Moczek, Armin; Jablonka, Eva; Odling-Smee, John

    2015-08-22

    Scientific activities take place within the structured sets of ideas and assumptions that define a field and its practices. The conceptual framework of evolutionary biology emerged with the Modern Synthesis in the early twentieth century and has since expanded into a highly successful research program to explore the processes of diversification and adaptation. Nonetheless, the ability of that framework satisfactorily to accommodate the rapid advances in developmental biology, genomics and ecology has been questioned. We review some of these arguments, focusing on literatures (evo-devo, developmental plasticity, inclusive inheritance and niche construction) whose implications for evolution can be interpreted in two ways—one that preserves the internal structure of contemporary evolutionary theory and one that points towards an alternative conceptual framework. The latter, which we label the 'extended evolutionary synthesis' (EES), retains the fundaments of evolutionary theory, but differs in its emphasis on the role of constructive processes in development and evolution, and reciprocal portrayals of causation. In the EES, developmental processes, operating through developmental bias, inclusive inheritance and niche construction, share responsibility for the direction and rate of evolution, the origin of character variation and organism-environment complementarity. We spell out the structure, core assumptions and novel predictions of the EES, and show how it can be deployed to stimulate and advance research in those fields that study or use evolutionary biology. © 2015 The Author(s).

  15. The extended evolutionary synthesis: its structure, assumptions and predictions

    Science.gov (United States)

    Laland, Kevin N.; Uller, Tobias; Feldman, Marcus W.; Sterelny, Kim; Müller, Gerd B.; Moczek, Armin; Jablonka, Eva; Odling-Smee, John

    2015-01-01

    Scientific activities take place within the structured sets of ideas and assumptions that define a field and its practices. The conceptual framework of evolutionary biology emerged with the Modern Synthesis in the early twentieth century and has since expanded into a highly successful research program to explore the processes of diversification and adaptation. Nonetheless, the ability of that framework satisfactorily to accommodate the rapid advances in developmental biology, genomics and ecology has been questioned. We review some of these arguments, focusing on literatures (evo-devo, developmental plasticity, inclusive inheritance and niche construction) whose implications for evolution can be interpreted in two ways—one that preserves the internal structure of contemporary evolutionary theory and one that points towards an alternative conceptual framework. The latter, which we label the ‘extended evolutionary synthesis' (EES), retains the fundaments of evolutionary theory, but differs in its emphasis on the role of constructive processes in development and evolution, and reciprocal portrayals of causation. In the EES, developmental processes, operating through developmental bias, inclusive inheritance and niche construction, share responsibility for the direction and rate of evolution, the origin of character variation and organism–environment complementarity. We spell out the structure, core assumptions and novel predictions of the EES, and show how it can be deployed to stimulate and advance research in those fields that study or use evolutionary biology. PMID:26246559

  16. A General Chemistry Experiment Incorporating Synthesis and Structural Determination

    Science.gov (United States)

    van Ryswyk, Hal

    1997-07-01

    An experiment for the general chemistry laboratory is described wherein gas chromatography-mass spectroscopy (GC-MS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) are used to characterize the products of a series of microscale reactions on vanillin. A single sophisticated instrument can be incorporated into the laboratory given sufficient attention to the use of sampling accessories and software macros. Synthetic experiments coupled with modern instrumental techniques can be used in the general chemistry laboratory to illustrate the concepts of synthesis, structure, bonding, and spectroscopy.

  17. Synthesis and Structural Analysis of Polyester Prodrugs of Norfloxacin

    Directory of Open Access Journals (Sweden)

    Waclaw Kolodziejski

    2008-01-01

    Full Text Available Two-, three- and four-arm, star-shaped poly(ε-caprolactone andpoly(D,L-lactide homopolymers, and copolymers of ε-caprolactone with D,L-lactide weresynthesized via ring-opening polymerization of cyclic esters in the presence of glycerol,penthaerythritol and poly(ethylene glycol as initiators and stannous octoate as a catalyst.Thus obtained oligomers were successfully used in the synthesis of novel macromolecularprodrugs of norfloxacin. The structures of the polymers and prodrugs were elucidated bymeans of MALDI-TOF MS, NMR and IR studies.

  18. Synthesis of resorcinolic lipids bearing structural similarities to cytosporone A

    Directory of Open Access Journals (Sweden)

    Edson dos Anjos dos Santos

    2009-01-01

    Full Text Available Inspired by the structure and biological activities of resorcinolic lipids and, particularly cytosporone A- a potent inhibitor of plantule germination and growth, we have performed the synthesis of the analogs 3-heptyl-3-hydroxy-5,7-dimethoxy-2-benzofuran-1(3H-one (1 and 3-heptyl-3-hydroxy-4,6-dimethoxy-2-benzofuran-1(3H-one (2. The intermediates and products were submitted to allelopathic test using Lactuca sativa L. seeds. Target compound 1 showed an inhibitory effect on germination and growth of hypocotyl and radicle in milimolar range.

  19. Synthesis of resorcinolic lipids bearing structural similarities to cytosporone A

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Edson dos Anjos dos; Beatriz, Adilson; Lima, Denis Pires de [Universidade Federal Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Centro de Ciencias Exatas e Tecnologia. Dept. de Quimica], e-mail: dlima@nin.ufms.br; Marques, Maria Rita; Leite, Carla Braga [Universidade Federal Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Centro de Ciencias Biologicas. Dept. de Morfofisiologia

    2009-07-01

    Inspired by the structure and biological activities of resorcinolic lipids and, particularly cytosporone A- a potent inhibitor of plantule germination and growth, we have performed the synthesis of the analogs 3-heptyl-3-hydroxy-5,7-dimethoxy-2-benzofuran-1(3H)-one (1) and 3-heptyl-3-hydroxy-4,6-dimethoxy-2-benzofuran-1(3H)-one (2). The intermediates and products were submitted to allelopathic test using Lactuca sativa L. seeds. Target compound 1 showed an inhibitory effect on germination and growth of hypocotyl and radicle in millimolar range. (author)

  20. Structural Sizing of the EDIN0620 Body Components Using the APAS Structural Synthesis Computer Program

    Science.gov (United States)

    Nolte, W. E.

    1976-01-01

    The use of a structural synthesis computer program to design components for a heavy lift launch vehicle is defined. A loads program was used to determine the vehicle shears, bending moments, and axial loads at two design loading conditions. A comparison was made between results from the structures program and the results of a weight estimating program which used historical data in determining component weights.

  1. Effect of concentrations of plasticizers on the sol-gel properties developed from alkoxides precursors

    Energy Technology Data Exchange (ETDEWEB)

    Kunst, Sandra Raquel; Longhi, Marielen; Zini, Lucas Pandolphi [Universidade de Caxias do Sul (CCET/UCS), Caxias do Sul, RS (Brazil). Centro de Ciências Exatas e Tecnologia; Beltrami, Lilian Vanessa Rossa; Boniatti, Rosiana; Cardoso, Henrique Ribeiro Piaggio; Vega, Maria Rita Ortega; Malfatti, Célia de Fraga, E-mail: lvrossa@yahoo.com.br [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Laboratorio de Pesquisa em Corrosão

    2017-07-01

    Coatings developed through sol-gel method is presented as an interesting replacement to chromium coating. Sol-gel method present advantages as high purity and excellent distribution of the components. The objective of this work is to synthesize and characterize a film obtained by sol-gel route. The film was prepared with 3-(trimethoxysilylpropyl) methacrylate (TMSPMA), tetraethoxysilane (TEOS) and cerium nitrate, using water and ethanol as solvents. Polyethyleneglycol (PEG) plasticizer was added at four different concentrations. The sol was characterized by techniques of viscosity, thermogravimetric analysis (TGA), X-ray diffraction (XRD) nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). The results showed that tetrafunctional alkoxides condensation was retarded by the plasticizer, forming a compact film. The film with 20 g.L-1 of PEG showed the best electrochemical behavior. (author)

  2. Synthesis of Carbon nano structures by plasma discharge

    International Nuclear Information System (INIS)

    Jimenez L, M.L.

    2007-01-01

    Due to the great quantity of applications of the carbon nano structures (NEC) in diverse areas like: synthesis of super-resistant materials, hydrogen storage, nano sensors generation and nano catalysts, it has seen the necessity to generate new processes of synthesis of this materials as well as to already improve those existent. The present work has as objective to optimize the NEC synthesis process by means of the electric arc method which uses alternating current to high frequencies (HF), obtaining relatively clean products; that is to say, it hardly presents amorphous material neither sludges. They stand out the obtaining of carbon nano fibers (NFC) by means of a luminescent-arch discharge, in a gas mixture of He-CH 4 with 34% at. Ni/10.32% at.Y like catalyst; at a frequency of 42 kHz and low power (300 W). This method benefits the amass of the particles in both electrodes due to the high frequencies. The time of duration of the process oscillates between 5 and 20 minutes. The obtained product was characterized by scanning electron microscopy (MEB), transmission electron microscopy (MET) to determine the NEC type obtained and by X-ray diffraction analysis and Raman spectroscopy for determining the purity of the samples. The NFC is relatively free of amorphous coal. The surface and structural analysis indicates that the fibers have a half diameter of 80 nm. It is also made, a study by optical emission spectroscopy of plasma using the Swan band for determining the temperature. (Author)

  3. Synthesis, structure and biological properties of active spirohydantoin derivatives

    Directory of Open Access Journals (Sweden)

    Lazić Anita M.

    2016-01-01

    Full Text Available Spirohidantoins represent an pharmacologically important class of heterocycles since many derivatives have been recognized that display interesting activities against a wide range of biological targets. First synthesis of cycloalkanespiro-5-hydantoins was performed by Bucherer and Lieb 1934 by the reaction of cycloalkanone, potassium cyanide and ammonium-carbonate at reflux in a mixture of ethanol and water. QSAR (Quantitative Structure-Activity Relationship studies showed that a wide range of biological activities of spirohydantoin derivatives strongly depend upon their structure. This paper describes different methods of synthesis of spirohydantoin derivatives, their physico-chemical properties and biological activity. It emphasizes the importance of cycloalkanespiro-5-hydantoins with anticonvulsant, antiproliferative, antipsychotic, antimicrobial and antiinflammatory properties as well as their importance in the treatment of diabetes. Numerous spirohydantoin compounds exhibit physiological activity such as serotonin and fibrinogen antagonist, inhibitors of the glycine binding site of the NMDA receptor also, antagonist of leukocyte cell adhesion, acting as allosteric inhibitors of the protein-protein interactions. Some spirohydantoin derivatives have been identified as antitumor agents. Their activity depends on the substituent presented at position N-3 of the hydantoin ring and increases in order alkene > ester > ether. Besides that, compounds that contain two electron withdrawing groups (e.g. fluorine or chlorine on the third and fourth position of the phenyl ring are better antitumor agents than compounds with a single electron withdrawing group. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  4. Synthesis, Structure, and Properties of Refractory Hard-Metal Borides

    Science.gov (United States)

    Lech, Andrew Thomas

    As the limits of what can be achieved with conventional hard compounds, such as tungsten carbide, are nearing reach, super-hard materials are an area of increasing industrial interest. The refractory hard metal borides, such as ReB2 and WB4, offer an increasingly attractive alternative to diamond and cubic boron nitride as a next-generation tool material. In this Thesis, a thorough discussion is made of the progress achieved by our laboratory towards understanding the synthesis, structure, and properties of these extremely hard compounds. Particular emphasis is placed on structural manipulation, solid solution formation, and the unique crystallographic manifestations of what might also be called "super-hard metals".

  5. A Scalable Synthesis Pathway to Nanoporous Metal Structures.

    Science.gov (United States)

    Coaty, Christopher; Zhou, Hongyao; Liu, Haodong; Liu, Ping

    2018-01-23

    A variety of nanoporous transition metals, Fe, Co, Au, Cu, and others, have been readily formed by a scalable, room-temperature synthesis process. Metal halide compounds are reacted with organolithium reductants in a nonpolar solvent to form metal/lithium halide nanocomposites. The lithium halide is then dissolved out of the nanocomposite with a common organic solvent, leaving behind a continuous, three-dimensional network of metal filaments that form a nanoporous structure. This approach is applicable to both noble metals (Cu, Au, Ag) and less-noble transition metals (Co, Fe, Ni). The microstructures of these nanoporous transition metals are tunable, as controlling the formation of the metal structure in the nanocomposite dictates the final metal structure. Microscopy studies and nitrogen adsorption analysis show these materials form pores ranging from 2 to 50 nm with specific surface areas from 1.0 m 2 /g to 160 m 2 /g. Our analysis also shows that pore size, pore volume, and filament size of the nanoporous metal networks depend on the mobility of target metal and the amount of lithium halide produced by the conversion reaction. Further, it has been demonstrated that hybrid nanoporous structures of two or more metals could be synthesized by performing the same process on mixtures of precursor compounds. Metals (e.g., Co and Cu) have been found to stabilize each other in nanoporous forms, resulting in smaller pore sizes and higher surface areas than each element in their pure forms. This scalable and versatile synthesis pathway greatly expands our access to additional compositions and microstructures of nanoporous metals.

  6. Biomimetic synthesis of ordered silica structures mediated by block copolypeptides.

    Science.gov (United States)

    Cha, J N; Stucky, G D; Morse, D E; Deming, T J

    2000-01-20

    In biological systems such as diatoms and sponges, the formation of solid silica structures with precisely controlled morphologies is directed by proteins and polysaccharides and occurs in water at neutral pH and ambient temperature. Laboratory methods, in contrast, have to rely on extreme pH conditions and/or surfactants to induce the condensation of silica precursors into specific morphologies or patterned structures. This contrast in processing conditions and the growing demand for benign synthesis methods that minimize adverse environmental effects have spurred much interest in biomimetic approaches in materials science. The recent demonstration that silicatein-a protein found in the silica spicules of the sponge Tethya aurantia--can hydrolyse and condense the precursor molecule tetraethoxysilane to form silica structures with controlled shapes at ambient conditions seems particularly promising in this context. Here we describe synthetic cysteine-lysine block copolypeptides that mimic the properties of silicatein: the copolypeptides self-assemble into structured aggregates that hydrolyse tetraethoxysilane while simultaneously directing the formation of ordered silica morphologies. We find that oxidation of the cysteine sulphydryl groups, which is known to affect the assembly of the block copolypeptide, allows us to produce different structures: hard silica spheres and well-defined columns of amorphous silica are produced using the fully reduced and the oxidized forms of the copolymer, respectively.

  7. Facile synthesis of gold nanomaterials with unusual crystal structures.

    Science.gov (United States)

    Fan, Zhanxi; Huang, Xiao; Chen, Ye; Huang, Wei; Zhang, Hua

    2017-11-01

    Gold (Au) nanomaterials have attracted wide research attention, owing to their high chemical stability, promising catalytic properties, excellent biocompatibility, unique electronic structure and outstanding localized surface plasmon resonance (LSPR) absorption properties; all of which are closely related to their size and shape. Recently, crystal-phase-controlled synthesis of noble metal nanomaterials has emerged as a promising strategy to tune their physicochemical properties. This protocol describes the detailed experimental procedures for the crystal-phase-controlled syntheses of Au nanomaterials with unusual crystal structures under mild conditions. Briefly, pure hexagonal close-packed (hcp) Au square sheets (AuSSs) with a thickness of ∼2.4 nm are synthesized using a graphene-oxide-assisted method in which HAuCl 4 is reduced by oleylamine in a mixture of hexane and ethanol. By using pure hexane as the solvent, well-dispersed ultrathin hcp/face-centered cubic (fcc) Au nanowires with a diameter of ∼1.6 nm on graphene oxide can be obtained. Meanwhile, hcp/fcc Au square-like plates with a side length of 200-400 nm are prepared via the secondary growth of Au on the hcp AuSSs. Remarkably, hexagonal (4H) Au nanoribbons with a thickness of 2.0-6.0 nm can be synthesized with a one-pot colloidal method in which HAuCl 4 is reduced by oleylamine in a mixed solvent of hexane and 1,2-dichloropropane. It takes 17-37 h for the synthesis of these Au nanomaterials with unusual crystal structures. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) are used to characterize the resultant Au nanomaterials, which could have many promising applications, such as biosensing, near-IR photothermal therapy, catalysis and surface-enhanced Raman scattering (SERS).

  8. Synthesis and crystal structure of chromium-bearing anhydrous wadsleyite

    Science.gov (United States)

    Sirotkina, E. A.; Bindi, L.; Bobrov, A. V.; Aksenov, S. M.; Irifune, T.

    2018-04-01

    A chromium-bearing wadsleyite (Cr- Wad) was synthesized in the model system Mg2SiO4-MgCr2O4 at 14 GPa and 1600 °C and studied from the chemical and structural point of views. Microprobe data gave the formula Mg1.930Cr0.120Si0.945O4, on the basis of 4 oxygen atoms. The crystal structure has been studied by single-crystal X-ray diffraction. The orthorhombic unit-cell parameters are: a = 5.6909(5) Å, b = 11.4640(10) Å, c = 8.2406(9) Å, V = 537.62(9) Å3, Z = 8. The structure, space group Imma, was refined to R 1 = 5.99% in anisotropic approximation using 1135 reflections with F o > 4σ( F o) and 43 parameters. Chromium was found to substitute for both Mg at the octahedral sites and Si at the tetrahedral site, according to the reaction VIMg2+ + IVSi4+ = VICr3+ + IVCr3+. On the whole, the structural topology is nearly identical to that of pure wadsleyite. The successful synthesis of Cr- Wad may be important for the thermobarometry of mantle phase associations.

  9. Synthesis, Characterization, and Electronic Structure Studies of Cubic Bi1.5ZnTa1.5O7 for Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Ganchimeg Perenlei

    2015-01-01

    Full Text Available Bi1.5ZnTa1.5O7 (BZT has been synthesized using an alkoxide based sol-gel reaction route. The evolution of the phases produced from the alkoxide precursors and their properties have been characterized as function of temperature using a combination of thermogravimetric analysis (TGA coupled with mass spectrometry (MS, infrared emission spectrometry (IES, X-ray diffraction (XRD, ultraviolet and visible (UV-Vis spectroscopy, Raman spectroscopy, and N2 adsorption/desorption isotherms. The lowest sintering temperature (600°C to obtain phase pure BZT powders with high surface area (14.5 m2/g has been determined from the thermal decomposition and phase analyses. The photocatalytic activity of the BZT powders has been tested for the decolorization of organic azo-dye and found to be photoactive under UV irradiation. The electronic band structure of the BZT has been investigated using density functional theory (DFT calculations to determine the band gap energy (3.12 eV and to compare it with experimental band gap (3.02 eV at 800°C from optical absorption measurements. An excellent match is obtained for an assumption of Zn cation substitutions at specifically ordered sites in the BZT structure.

  10. Different mechanisms at different temperatures for the ring-opening polymerization of lactide catalyzed by binuclear magnesium and zinc alkoxides.

    Science.gov (United States)

    Sun, Yangyang; Cui, Yaqin; Xiong, Jiao; Dai, Zhongran; Tang, Ning; Wu, Jincai

    2015-10-07

    Two binuclear magnesium and zinc alkoxides supported by a bis-salalen type dinucleating heptadentate Schiff base ligand were synthesized and fully characterized. The two complexes are efficient initiators for the ring-opening polymerization (ROP) of L-lactide, affording polymers with narrow polydispersities and desirable molecular weights. Interestingly, the mechanisms for the ROP of lactide are different at different temperatures. At a high temperature of 130 °C, a coordination-insertion mechanism is reasonable for the bulk melt polymerization of lactide. At a low temperature, the alkoxide cannot initiate the ROP reaction; however, upon the addition of external benzyl alcohol into the system, the ROP of lactide can smoothly proceed via an "activated monomer" mechanism. In addition, these complexes display slight stereo-selectivity for the ring-opening polymerization of rac-lactide, affording partially isotactic polylactide in toluene with a Pm value of 0.59.

  11. Synthesis and structural studies of copper sulfide nanocrystals

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    Full Text Available We report the synthesis and structural studies of copper sulfide nanocrystals from copper(II dithiocarbamate single molecule precursors. The optical studies of the as-prepared copper sulfide nanoparticles were carried out using UV–Visible and photoluminescence spectroscopy. The absorption spectra show absorption band edges at 287 nm and exhibit considerable blue shift that could be ascribed to the quantum confinement effects as a result of the small crystallite sizes of the nanoparticles and the photoluminescence spectra show emission curves that are red shifted with respect to the absorption band edges. The structural studies were carried out using powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The XRD patterns revealed the formation of hexagonal structure of covellite CuS with estimated crystallite sizes of 17.3–18.6 nm. The TEM images showed particles with almost spherical or rod shapes with average crystallite sizes of 3–9.8 nm. SEM images showed morphology with ball-like microsphere on the surfaces and EDS spectra confirmed the presence of CuS nanoparticles. Keywords: CuS, Dithiocarbamate, Nanoparticles, Electron microscopy, AFM

  12. Synthesis, Structure, Stability and Redispersion of Gold-based Nanoparticles

    Science.gov (United States)

    Tiruvalam, Ram Chandra

    Nanoscale gold has been shown to possess an intriguing combination of unexpected optical, photochemical and catalytic properties. The ability to control the size, shape, morphology, composition and dispersion of gold-based nanostructures is key to optimizing their performance for nanotechnology applications. The advanced electron microscopy studies described in this thesis analyze three important aspects of gold and gold-palladium alloy nanoparticles: namely, (i) the ability to synthesize gold nanoparticles of controlled size and shape in an aqueous medium; (ii) the colloidal preparation of designer gold-palladium alloys for selective oxidation catalysis; and (iii) the ability to disperse gold as finely and homogeneously as possible on a metal oxide or carbon support. The ability to exploit the nanoscale properties of gold for various engineering applications often depends on our ability to control size and shape of the nanoscale entity by careful manipulation of the synthesis parameters. We have explored an aqueous based synthesis route, using oleylamine as both a reductant and surfactant, for preparing gold nanostructures. By systematically varying synthesis parameters such as oleylamine concentration, reaction temperature, and aging time it is possible to identify processing regimens that generate Au nanostructures having either pseudo-spherical, faceted polyhedral, nanostar or wire shaped morphologies. Furthermore, by quenching the reaction partway through it is possible to create a class of metastable Au-containing structures such as nanocubes, nanoboxes and nanowires. Possible formation mechanisms for these gold based nano-objects are discussed. There is a growing interest in using supported bimetallic AuPd alloy nanoparticles for selective oxidation reactions. In this study, a systematic series of size controlled AuPd bimetallic particles have been prepared by colloidal synthesis methods. Particles having random alloy structures, as well as `designer

  13. SYNTHESIS OF STYRENE-BUTADIENE STATISTIC COPOLYMERS CONTAINING MAGNESIUM INITIATOR

    Directory of Open Access Journals (Sweden)

    A. V. Firsova

    2015-01-01

    Full Text Available The article discusses the use of organomagnesium initiators in the synthesis of styrene-butadiene random copolymer (SBR obtained solution polymerization and their influence on the properties of rubber. Selected organic magnesium dialkyl initiator is combined with a modifier, which is a mixed alkoxide of an alkali and alkaline earth metals, which allows to control the micr ostructure of the diene polymer and its molecular weight characteristics. Alcohol derivatives selected high-boiling alcohols tetra (hydroxypropyl ethylenediamine (lapromol 294 and tetrahydrofurfuryl alcohol (TGFS. Selection of high-boiling alcohols due to the fact that the destruction of alkoxide with aqueous polymer degassing they do not fall into the return solvent and almost fall into the exact water. The metal components of alkoxides are lithium, sodium, potassium, magnesium and calcium. The resulting solutions are stable when stored modifier t hroughout the year even at -40 °C. The scheme of obtaining the new catalyst systems based organomagnesium and alcoxide of alkali and alkaline earth metals, which yields as functionalized SBR with a statistical and a distribution block of butadiene and styrene was developed. The process of copolymerization with styrene to butadiene organomagnesium initiators as using an organolithium compound (n-butyllithium was carried out, and without it. Found that the addition of n-butyllithium in the reaction mixture leads to a sharp increase in the rate of reaction. The results of studies of the effect of composition of the initiator system on the structure of diene polymers. It was revealed that a mixed initiator system affords a high conversion of monomers (to 90 % in 1 hour 1,2-polybutadiene content increased to 60 %. The process of polymerization of only a mixture of organomagnesium initiators and alcoxide of alkali and alkaline earth metals are not actively proceeds, conversion of the monomers reaches to 90 % in 4 hours, the microstructure

  14. Process Development in the Preparation and Characterization of Silicon Alkoxide From Rice Husk

    International Nuclear Information System (INIS)

    Khin San Win; Toe Shein; Nyunt Wynn

    2011-12-01

    The preparation and characterization of silicon alkoxide (silicon isopropoxide) from rice husk char has been studied. In the investigation, four kinds of Myanmar paddies were chemically assayed. Analyses showed the silicon contend varies from 73-92% . Based on the silicon content, the process development in the production of silicon isopropoxide was carried out. In the process development, silicon isopropoxide with a yield of 44.21% was achieved by the direct reaction of isopropanol in situ by silicon tetrachloride, which was directly produced by the chlorination of rice husk char at the high temperature range of 900-1100 C. The novelity of the process was that, silicon isopropoxide was achieved in situ and not by using the old process, where generally isopropanol was reacted with silicon tetrachloride. The physiochemical properties of silicon isopropoxide was confirmed by conventional and modern techniques. In the investigation, the starting materials, silica in the reaction products were characterized, identified and confirmed by modren techniques. Silicon isopropoxide can be a sources of pore silica whereby silicon of 97-99% of purity can be achieved.

  15. Structuration, space and time: the reconstruction of Anthony Giddens’ «structure-agency» synthesis theory

    Directory of Open Access Journals (Sweden)

    A. D. Osypchuk

    2014-10-01

    Full Text Available The article presents a theoretical and analytical reconstruction of A.Giddens’ Structuration theory as an attempt of ‘structure-agency’ synthesis in sociology. The concept of structuration is introduced by Giddens to solve the problem of duality of structure and agency where the former is defined as rules and resources. Structuration can’t be understood without reference to Giddens’ use of ‘time-space’ concept and related locality and regionalization concepts. Article analyses in details which theoretical and methodological possibilities and limitations comes out of defining structuration as constant flux of conducts in time-space, especially in regard to snapshots of previous conditions of system or structure and memories about them. The article also deals with the concepts of presence, locality, and regionalization that are the result of critical development of time geography approach and are based on combining time and space into one inseparable dimension. The main types and modes of regionalization are reviewed. It is emphasized that through regionalization, locality, and forms of presence and of routine practices Giddens defines not only social institutions but also social system. There is a brief theoretical and methodological discussion of correlation between social structure and social system and of the potential application of Structuration theory to analysis of social change.

  16. Ligand-protected gold clusters: the structure, synthesis and applications

    Science.gov (United States)

    Pichugina, D. A.; Kuz'menko, N. E.; Shestakov, A. F.

    2015-11-01

    Modern concepts of the structure and properties of atomic gold clusters protected by thiolate, selenolate, phosphine and phenylacetylene ligands are analyzed. Within the framework of the superatom theory, the 'divide and protect' approach and the structure rule, the stability and composition of a cluster are determined by the structure of the cluster core, the type of ligands and the total number of valence electrons. Methods of selective synthesis of gold clusters in solution and on the surface of inorganic composites based, in particular, on the reaction of Aun with RS, RSe, PhC≡C, Hal ligands or functional groups of proteins, on stabilization of clusters in cavities of the α-, β and γ-cyclodextrin molecules (Au15 and Au25) and on anchorage to a support surface (Au25/SiO2, Au20/C, Au10/FeOx) are reviewed. Problems in this field are also discussed. Among the methods for cluster structure prediction, particular attention is given to the theoretical approaches based on the density functional theory (DFT). The structures of a number of synthesized clusters are described using the results obtained by X-ray diffraction analysis and DFT calculations. A possible mechanism of formation of the SR(AuSR)n 'staple' units in the cluster shell is proposed. The structure and properties of bimetallic clusters MxAunLm (M=Pd, Pt, Ag, Cu) are discussed. The Pd or Pt atom is located at the centre of the cluster, whereas Ag and Cu atoms form bimetallic compounds in which the heteroatom is located on the surface of the cluster core or in the 'staple' units. The optical properties, fluorescence and luminescence of ligand-protected gold clusters originate from the quantum effects of the Au atoms in the cluster core and in the oligomeric SR(AuSR)x units in the cluster shell. Homogeneous and heterogeneous reactions catalyzed by atomic gold clusters are discussed in the context of the reaction mechanism and the nature of the active sites. The bibliography includes 345 references.

  17. Synthesis, X-ray crystal structure, DNA binding and Nuclease activity ...

    Indian Academy of Sciences (India)

    s12039-016-1125-x. Synthesis, X-ray crystal structure, DNA binding and Nuclease activity of lanthanide(III) complexes of 2-benzoylpyridine acetylhydrazone. KARREDDULA RAJA, AKKILI SUSEELAMMA and KATREDDI HUSSAIN REDDY. ∗.

  18. Using Combustion Synthesis to Reinforce Berms and Other Regolith Structures

    Science.gov (United States)

    Rodriquez, Gary

    2013-01-01

    The Moonraker Excavator and other tools under development for use on the Moon, Mars, and asteroids will be employed to construct a number of civil engineering projects and to mine the soil. Mounds of loose soil will be subject to the local transport mechanisms plus artificial mechanisms such as blast effects from landers and erosion from surface vehicles. Some of these structures will require some permanence, with a minimum of maintenance and upkeep. Combustion Synthesis (CS) is a family of processes and techniques whereby chemistry is used to transform materials, often creating flame in a hard vacuum. CS can be used to stabilize civil engineering works such as berms, habitat shielding, ramps, pads, roadways, and the like. The method is to unroll thin sheets of CS fabric between layers of regolith and then fire the fabric, creating a continuous sheet of crusty material to be interposed among layers of loose regolith. The combination of low-energy processes, ISRU (in situ resource utilization) excavator, and CS fabrics, seems compelling as a general method for establishing structures of some permanence and utility, especially in the role of robotic missions as precursors to manned exploration and settlement. In robotic precursory missions, excavator/ mobility ensembles mine the Lunar surface, erect constructions of soil, and dispense sheets of CS fabrics that are covered with layers of soil, fired, and then again covered with layers of soil, iterating until the desired dimensions and forms are achieved. At the base of each berm, for example, is a shallow trench lined with CS fabric, fired and filled, mounded, and then covered and fired, iteratively to provide a footing against lateral shear. A larger trench is host to a habitat module, backfilled, covered with fabric, covered with soil, and fired. Covering the applied CS fabric with layers of soil before firing allows the resulting matrix to incorporate soil both above and below the fabric ply into the fused layer

  19. Reactions of aromatic nitro-compounds. LV. Anionic sigma-complexes of sym-trinitrobenzene with the alkoxides of dihydric alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Mel' nikov, A.I.; Gitis, S.S.; Kaminskii, A.Ya.

    1986-12-20

    The reactions of alkoxides of dihydric alcohols with 2,4,6-trinitroanisole and picryl chloride have been studied. The reaction between 2,4,6-trinitroanisole and sodium 2-hydroxyethoxide, 3-hydroxypropoxide, 4-hydroxybutoxide, and 2-methoxyethoxide gives the unsymmetrical 1-methoxy-1-hydroxyalkoxy-2,4,6-trinitrocyclohexa-2,5-dienate sigma-complexes, which are converted on heating into the 1,1-dihydroxyalkoxy-2,4-6-trinitrocyclohexa-2,5-dienate sigma-complexes. In the case of sodium 1-methoxy-1-(..beta..-hydroxyethoxy)-2,4,6-trinitrocyclohexa-2,5-dienate, heating results in intramolecular spirocyclization of the ..beta..-hydroxyethoxy grouping to give sodium 6,8,10-trinitro-1,4-dioxaspiro(4,5)deca-6,9-dienate. The reaction of sodium 3-hydroxy-propoxide, 4-hydroxybutoxide, 2-methoxyethoxide, and diethyleneglycolate with picryl chloride gives the symmetrical 1,1-dihyroxyalkoxy sigma-complexes, while sodium 2-hydroxyethoxide forms a sigma-complex with a 1,3-dioxolane spiro-ring. The composition and structures of the sigma-complexes, isolated as their sodium salts, were established by their elemental analyses and PMR and IR spectroscopy.

  20. Thermochromic behavior of vanadium(IV) alkoxides in solution: a molecular modeling approach; Termocromismo em solucoes de alcoxidos de vanadio(IV): uma abordagem pela modelagem molecular

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Alexandre C. de; Westrup, Katia C. M.; Nunes, Giovana G.; Gulin, Denis J.; Haiduke, Roberto L. A.; Soares, Jaisa F.; Sa, Eduardo L. de [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica

    2010-07-01

    The thermochromic behavior exhibited by vanadium(IV) alkoxides, [V{sub 2}(mu-OPr{sup i}){sub 2}(OPr{sup i}){sub 6}] and [V{sub 2}(m-ONep){sub 2}(ONep){sub 6}], OPr{sup i} = isopropoxide and ONep = neopentoxide, was studied by molecular modeling using DFT, TDDFT and INDO/S methods. The vibrational and electronic spectra calculated for [V{sub 2}(mu-OPr{sup i}){sub 2}(OPr{sup i}){sub 6}] were very similar to the experimental data registered for crystalline samples of the complex and for its solutions at low temperature (< 210 K), while spectra recorded at high temperature (> 315 K) were compatible with those calculated for the monomeric form, [V(OPr{sup i}){sub 4}]. These results consistently point to a monomer/dimer equilibrium as an explanation for the solution thermochromism of {l_brace}V(OPr{sup i})-4{r_brace}{sub n}. In spite of the structural similarity between [V{sub 2}(mu-ONep){sub 2}(ONep){sub 6}] and [V{sub 2}(mu-OPr{sup i}){sub 2}(OPr{sup i}){sub 6}] in the solid state, the thermochromic behavior of the former could not be explained by the same model, and the possibility of tetranuclear aggregation at low temperatures was also investigated. (author)

  1. Structural archetypes in nickel(II) hybrid vanadates. Towards a directed hydrothermal synthesis

    International Nuclear Information System (INIS)

    Luis, R. Fernandez de; Urtiaga, M.K.; Mesa, J.L.; Rojo, T.; Arriortua, M.I.

    2009-01-01

    In the present work, we relate the modifications of the initial synthesis parameters (pH value, stoichiometry and concentration) with the different structural archetypes obtained in the {Ni/Bpy/VO} and {Ni/Bpe/VO} systems (4,4'-bipyridine (Bpy), 1,2-di(4-pyridyl) ethylene (Bpe)). The vanadium coordination is partially controlled by the hydrothermal synthesis conditions, and the final crystal structures depend on the synergetic interaction between the metal-organic subnets and the vanadium oxide subunits.

  2. Total synthesis, structure, and oral absorption of a thiazole cyclic peptide, sanguinamide A

    DEFF Research Database (Denmark)

    Nielsen, Daniel S; Hoang, Huy N; Lohman, Rink-Jan

    2012-01-01

    The first total synthesis and three-dimensional solution structure are reported for sanguinamide A, a thiazole-containing cyclic peptide from the sea slug H. sanguineus. Solution phase fragment synthesis, solid phase fragment assembly, and solution macrocyclization were combined to give (1) in 10......% yield. Spectral properties were identical for the natural product, requiring revision of its structure from (2) to (1). Intramolecular transannular hydrogen bonds help to bury polar atoms, which enables oral absorption from the gut....

  3. A bipyridyl thorium metallocene: synthesis, structure and reactivity.

    Science.gov (United States)

    Ren, Wenshan; Song, Haibin; Zi, Guofu; Walter, Marc D

    2012-05-21

    The synthesis, structure and reactivity of a new bipy thorium metallocene have been studied. The reduction of the thorium chloride metallocene [η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)ThCl(2) (1) with potassium graphite in the presence of 2,2'-bipyridine gives the purple bipy metallocene [η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)Th(bipy) (2) in good yield. Complex 2 has been fully characterized by various spectroscopic techniques, elemental analysis and X-ray diffraction analysis. Complex 2 reacts cleanly with trityl chloride, silver halides and diphenyl diselenide, leading to the halide metallocenes [η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)ThX(2) (X = Cl (1), Br (3), I (4)) and [η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)Th(F)(μ-F)(3)Th[η(5)-1,3-(Me(3)C)(2)C(5)H(3)](F)(bipy) (5), and selenido metallocene [η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)Th(SePh)(2) (6), in good conversions. In addition, 2 cleaves the C[double bond, length as m-dash]S bond of CS(2) to give the sulfido complex, [η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)ThS (7), which further undergoes an irreversible dimerization or nucleophilic addition with CS(2), leading to the dimeric sulfido complex {[η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)Th}(μ-S)(2) (8) and dimeric trithiocarbonate complex {[η(5)-1,3-(Me(3)C)(2)C(5)H(3)](2)Th}(μ-CS(3))(2) (10) in good yields, respectively.

  4. Synthesis, structure and electronic structure of a new polymorph of CaGe2

    International Nuclear Information System (INIS)

    Tobash, Paul H.; Bobev, Svilen

    2007-01-01

    Reported are the flux synthesis, the crystal structure determination, the properties and the band structure calculations of a new polymorph of CaGe 2 , which crystallizes with the hexagonal space group P6 3 mc (no. 186) with cell parameters of a=3.9966(9) and c=10.211(4)A (Z=2; Pearson's code hP6). The structure can be viewed as puckered layers of three-bonded germanium atoms, ∼ 2 [Ge 2 ] 2- , which are stacked along the direction of the c-axis in an ABAB-fashion. The germanium polyanionic layers are separated by the Ca cations. As such, this structure is closely related to the structure of the other CaGe 2 polymorph, which crystallizes with the rhombohedral CaSi 2 type in the R3-bar m space group (No. 166), where the ∼ 2 [Ge 2 ] 2- layers are arranged in an AA'BB'CC'-fashion, and are also interspaced by Ca 2+ cations. LMTO calculations suggest that in spite of the formal closed-shell configuration for all atoms and the apparent adherence to the Zintl rules for electron counting, i.e., Ca 2+ [3b-Ge 1- ] 2 ), the phase will be a poor metal due to a small Ca-3d-Ge-4p band overlap. Magnetic susceptibility measurements as a function of the temperature indicate that the new CaGe 2 polymorph exhibits weak, temperature independent, Pauli-paramagnetism

  5. Synthesis and structure of bis(β-dibenzoyl methanato -O,O') (aquo-O ...

    Indian Academy of Sciences (India)

    Synthesis and structure of bis(β-dibenzoyl methanato -O,O') (aquo-O) dioxouranium (VI) compound ... Keywords. β-diketonates; uranyl ion; adduct compound; crystal structure; hydrogen bonding. 1. Introduction. Structural studies on uranyl ... crystalline product obtained was filtered, washed with ether and dried. The crystal ...

  6. Local Synthesis of Carbon Nanotubes in Silicon Microsystems: The Effect of Temperature Distribution on Growth Structure

    Directory of Open Access Journals (Sweden)

    Knut E. Aasmundtveit

    2013-07-01

    Full Text Available Local synthesis and direct integration of carbon nanotubes (CNTs into microsystems is a promising method for producing CNT-based devices in a single step, low-cost, and wafer-level, CMOS/MEMS-compatible process. In this report, the structure of the locally grown CNTs are studied by transmission imaging in scanning electron microscopy—S(TEM. The characterization is performed directly on the microsystem, without any post-synthesis processing required. The results show an effect of temperature on the structure of CNTs: high temperature favors thin and regular structures, whereas low temperature favors “bamboo-like” structures.

  7. Green synthesis and structural control of metal and mineral nanostructures

    DEFF Research Database (Denmark)

    Engelbrekt, Christian

    nanomaterials. In the first approach, time-resolved chronopotentiometry, pH, conductivity and turbidity, and ultraviolet-visible light spectroscopy were employed to follow the green synthesis of gold nanoparticles. Several distinct phases were observed with all techniques providing a broad picture....... Detailed crystallographic characterization was obtained by combining X-ray diffraction and infrared spectroscopy. The synthesis of CuO was further optimized and the flat, rod-shaped nanostructures applied as heterogeneous catalysts for oxidative dehydrogenation reactions. High activity and good reusability...

  8. Total synthesis based on the originally claimed structure of mucosin.

    Science.gov (United States)

    Gallantree-Smith, Harrison C; Antonsen, Simen G; Görbitz, Carl H; Hansen, Trond V; Nolsøe, Jens M J; Stenstrøm, Yngve H

    2016-09-28

    The first total synthesis aimed at the naturally occurring eicosanoid bicycle mucosin is reported. A practical route has been devised allowing the issues relating to the previous assignment of stereochemistry to be examined. X-ray crystallography was performed on a late stage intermediate to pinpoint the topological relationship displayed by the featured bicyclo[4.3.0]non-3-ene scaffold.

  9. Synthesis, characterization and crystal structure of new nickel ...

    Indian Academy of Sciences (India)

    School of Chemistry, University College of Science, University of Tehran, Tehran, Iran. Email: alnema@khayam.ut.ac.ir ... nation polymers and coordination complexes, is a suit- able building block for supramolecular ..... Kianpour G, Salavati-Niasari M and Emadi H 2013. Precipitation synthesis and characterization of cobalt.

  10. Synthesis and structure of copper(II) complexes: Potential cyanide ...

    Indian Academy of Sciences (India)

    ing the oxidase models. The necessity to make progress in developing copper oxidase models requires synthesis of appropriate copper complexes to rationalize the func- tions of such oxidases unequivocally.46–52 Therefore, to study the coordination chemistry of Cu(II) incorpo- rating the new azo ligands,53 HLa and HLb, ...

  11. Synthesis, characterization, crystal structure and DNA-binding study ...

    Indian Academy of Sciences (India)

    BOLIN

    SYNOPSIS. Synthesis and characterization of four mononuclear eight coordinated cadmium(II) complexes with newly explored carboxamide derivatives and study of interaction with calf-thymus DNA are reported. The results suggest that neutral complexes 2a and 2b bind to DNA in an intercalative mode. On the other hand, ...

  12. synthesis and structural studies of first row transition metal ...

    African Journals Online (AJOL)

    a

    deals with the synthesis and characterization of NBHQO and its complexes with chromium(III), manganese(II), iron(III), cobalt(II), nickel(II) and copper(II). EXPERIMENTAL. All the chemicals used were either of AR or chemically pure grade. Mass spectra were recorded on a Perkin-Elmer Hitachi-6L spectrometer and 1H NMR ...

  13. Synthesis, structural characterization and biological activity of a ...

    Indian Academy of Sciences (India)

    3.1 Synthesis and formulation. Schiff base ligand H2L was synthesized by 1:1 conden- sation of O-aminophenol and O-vanillin in dehydrated alcohol. 1 was prepared using reaction among Zn(II) salt and the ligand in methanol. Coordination geo- metry of 1 was determined by different spectroscopic characterization.

  14. Sound Synthesis and Musical Composition by Physical Modelling of Self-Sustained Oscillating Structures

    OpenAIRE

    Poyer, François; Cadoz, Claude

    2007-01-01

    Paper 3 - Audio Synthesis (Oral Presentations); International audience; In this paper, we present the first results of a study that is carried out with the sound synthesis and musical creation environment GENESIS on self-sustained oscillating structures models. Based on the mass-interaction CORDIS-ANIMA physical modelling formalism, GENESIS has got the noteworthy property that it allows to work both on sound itself and on musical composition in a single coherent environment. By taking as a st...

  15. Synthesis and Structural Studies of Nanocrystalline Cd 0.3 Zn 0.7 Fe ...

    African Journals Online (AJOL)

    Synthesis and Structural Studies of Nanocrystalline Cd 0.3 Zn 0.7 Fe 2 O 4. ... South African Journal of Chemistry ... The synthesis of Cd0.3Zn0.7Fe2O4 nanoparticles has been achieved by a simple thermal decomposition method from the inorganic precursor, Cdd0.3Zn0.7Fe2(cin)3(N2H4)2, which was obtained by a novel ...

  16. MWW-type titanosilicate synthesis, structural modification and catalytic applications to green oxidations

    CERN Document Server

    Wu, Peng; Xu, Le; Liu, Yueming; He, Mingyuan

    2013-01-01

    This book provides a comprehensive review of a new generation of selective oxidation titanosilicate catalysts with the MWW topology (Ti-MWW) based on the research achievements of the past 12 years. It gives an overview of the synthesis, structure modification and catalytic properties of Ti-MWW. Ti-MWW can readily be prepared by means of direct hydrothermal synthesis with crystallization-supporting agents, using dual-structure-directing agents and a dry-gel conversion technique. It also can be post-synthesized through unique reversible structure transformation and liquid-phase isomorphous subst

  17. Merremoside D: de novo synthesis of the purported structure, NMR analysis, and comparison of spectral data.

    Science.gov (United States)

    Sharif, Ehesan U; Wang, Hua-Yu Leo; Akhmedov, Novruz G; O'Doherty, George A

    2014-01-17

    The first synthesis of the purported structure of Merremoside D has been achieved in 22 longest linear steps. The de novo asymmetric synthesis relied on the use of asymmetric catalysis to selectively install all 21 stereocenters in the final compounds from commercially available achiral starting materials. Adiabatic gradient 2D NMR techniques (gHSQCAD, gHMBCAD, gH2BCAD, gHSQCTOXYAD, ROESYAD) were used to completely assign the structure of synthetic Merremoside D. Comparison of our assignments with the limited NMR data reported for natural Merremoside D allows for the tentative confirmation of its structure.

  18. Synthesis of Nano-Particles in Flames

    DEFF Research Database (Denmark)

    Johannessen, Tue

    The scope of this work is to investigate the synthesis of aluminum oxide particles in flames from the combustion of an aluminum alkoxide precursor.A general introduction to particles formation in the gas phase is presented with emphasis on the mechanisms that control the particle morphology after...... energy expression.Furthermore, the model is validated by comparison with experimental data of the flame synthesis of titania by combustion of TiCl4 previously presented by Pratsinis et al. (1996).The combination of particle dynamics and CFD simulations has proved to be an efficient method...

  19. Synthesis, structure and photocatalytic properties of β-ZrMo2O8

    Indian Academy of Sciences (India)

    Administrator

    Synthesis, structure and photocatalytic properties of β-ZrMo2O8. PRANGYA PARIMITA SAHOO, S SUMITHRA, GIRIDHAR MADRAS and. T N GURU ROW*. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India. Abstract. Monoclinic ZrMo2O8 was synthesized via solid state method ...

  20. Solvent-free synthesis of nanosized hierarchical sodalite zeolite with a multi-hollow polycrystalline structure

    KAUST Repository

    Zeng, Shangjing

    2016-08-03

    A solvent-free route is developed for preparing nanoscale sodalite zeolite with a multi-hollow structure. Furthermore, the synthesis of nanosized hollow sodalite polycrystalline aggregates with a mesoporous structure and high crystallinity is investigated by adding an organosilane surfactant as a mesopore-generating agent.

  1. Synthesis, structural and ferromagnetic properties of La1–x Kx ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Synthesis, structural and ferromagnetic properties of La1–KMnO3 (0.0≤ 0.25) phases by solution combustion method ... Structural parameters were determined by the Rietveld refinement method using powder XRD data. Parent ... The ratio of the Mn3+/Mn4+ was determined by the iodometric titration.

  2. Methodology in structural determination and synthesis of insect pheromone

    Directory of Open Access Journals (Sweden)

    Guo-Qiang Lin

    1991-01-01

    Full Text Available By means of ethereal washing of insect pheromone glands of female moths, GC-MS detection along with microchemical reactions and electroantennogram (EAG survey, six economically important insect species were targeted for pheromone identification. The discovery of a natural pheromone inhibitor, chemo-selectivity and species isolation by pheromone will be described. The modified triple bond migration and triethylamine liganded vinyl cuprate were applied for achiral pheromone synthesis in double bond formation. Some optically active pheromones and their stereoisomers were synthesized through chiral pool or asymmetric synthesis. Some examples of chiral recognition of insects towards their chiral pheromones will be discussed. A CaH2 and silica gel catalyzed Sharpless Expoxidation Reaction was found in shortening the reaction time.

  3. New data structures and algorithms for logic synthesis and verification

    CERN Document Server

    Amaru, Luca Gaetano

    2017-01-01

    This book introduces new logic primitives for electronic design automation tools. The author approaches fundamental EDA problems from a different, unconventional perspective, in order to demonstrate the key role of rethinking EDA solutions in overcoming technological limitations of present and future technologies. The author discusses techniques that improve the efficiency of logic representation, manipulation and optimization tasks by taking advantage of majority and biconditional logic primitives. Readers will be enabled to accelerate formal methods by studying core properties of logic circuits and developing new frameworks for logic reasoning engines. · Provides a comprehensive, theoretical study on majority and biconditional logic for logic synthesis; · Updates the current scenario in synthesis and verification – especially in light of emerging technologies; · Demonstrates applications to CMOS technology and emerging technologies.

  4. The synthesis and structure of new vinylogous carbamates of sparteine

    Science.gov (United States)

    Włodarczak, Jacek; Wysocka, Waleria; Katrusiak, Andrzej

    2010-05-01

    Synthesis of new ( E)-(-)-[2-methyl ( 2), ethyl ( 3), isopropyl ( 4), benzyl ( 5) and phenyl ( 6)] carbonylmethylideno-17-oxosparteine by the Eschenmoser coupling reaction has been described. Stereochemistry of these compounds has been determined by 13C and 1H NMR and that of compound 2 additionally by X-ray analysis. The Haasnoot equation has been used to determine the HCCH dihedral angle in ( E)-(-)-2-methyl-(methylcarbonylomethylideno)-17-oxosparteine on the basis of NMR spectroscopy.

  5. Organized Mesoporous Alumina: Synthesis, Structure and Potential in Catalysis

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří

    2003-01-01

    Roč. 254, - (2003), s. 327-338 ISSN 0926-860X R&D Projects: GA AV ČR IAA4040001; GA ČR GA104/02/0571; GA MŠk ME 404 Institutional research plan: CEZ:AV0Z4040901 Keywords : organized mesoporous alumina * mesoporous molecular sieves * synthesis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.825, year: 2003

  6. Structure sensitivity of Cu and CuZn catalysts relevant to industrial methanol synthesis

    Science.gov (United States)

    van den Berg, Roy; Prieto, Gonzalo; Korpershoek, Gerda; van der Wal, Lars I.; van Bunningen, Arnoldus J.; Lægsgaard-Jørgensen, Susanne; de Jongh, Petra E.; de Jong, Krijn P.

    2016-01-01

    For decades it has been debated whether the conversion of synthesis gas to methanol over copper catalysts is sensitive or insensitive to the structure of the copper surface. Here we have systematically investigated the effect of the copper particle size in the range where changes in surface structure occur, that is, below 10 nm, for catalysts with and without zinc promotor at industrially relevant conditions for methanol synthesis. Regardless of the presence or absence of a zinc promotor in the form of zinc oxide or zinc silicate, the surface-specific activity decreases significantly for copper particles smaller than 8 nm, thus revealing structure sensitivity. In view of recent theoretical studies we propose that the methanol synthesis reaction takes place at copper surface sites with a unique configuration of atoms such as step-edge sites, which smaller particles cannot accommodate. PMID:27703166

  7. Synthesis and structure of two-dimensional transition-metal dichalcogenides

    KAUST Repository

    Shi, Yumeng

    2015-07-13

    Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) exhibit unique electrical, optical, thermal, and mechanical properties, which enable them to be used as building blocks in compact and lightweight integrated electronic systems. The controllable and reliable synthesis of atomically thin TMDCs is essential for their practical application. Recent progress in large-area synthesis of monolayer TMDCs paves the way for practical production of various 2D TMDC layers. The intrinsic optical and electrical properties of monolayer TMDCs can be defined by stoichiometry during synthesis. By manipulating the lattice structure or layer stacking manner, it is possible to create atomically thin van der Waals materials with unique and unexplored physical properties. In this article, we review recent developments in the synthesis of TMDC monolayers, alloys, and heterostructures, which shine light on the design of novel TMDCs with desired functional properties.

  8. Synthesis of computational structures for analog signal processing

    CERN Document Server

    Popa, Cosmin Radu

    2011-01-01

    Presents the most important classes of computational structures for analog signal processing, including differential or multiplier structures, squaring or square-rooting circuits, exponential or Euclidean distance structures and active resistor circuitsIntroduces the original concept of the multifunctional circuit, an active structure that is able to implement, starting from the same circuit core, a multitude of continuous mathematical functionsCovers mathematical analysis, design and implementation of a multitude of function generator structures

  9. Influence of chelation ratio of metal alkoxides on aging of PZT 53/47 ...

    Indian Academy of Sciences (India)

    based synthesis routes, generally demands the use of chelating agents in order to avoid fast hydrolysis and also to allow an easier manipulation of intermediates as well as final solutions. Under these conditions, stability issues sometimes can be ...

  10. Structural archetypes in nickel(II) hybrid vanadates. Towards a directed hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Luis, R. Fernandez de; Urtiaga, M.K. [Dpto. Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Mesa, J.L.; Rojo, T. [Dpto. Quimica Inorganica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Arriortua, M.I. [Dpto. Mineralogia y Petrologia, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/UPV/EHU, Apdo. 644, 48080 Bilbao (Spain)], E-mail: maribel.arriortua@ehu.es

    2009-07-01

    In the present work, we relate the modifications of the initial synthesis parameters (pH value, stoichiometry and concentration) with the different structural archetypes obtained in the {l_brace}Ni/Bpy/VO{r_brace} and {l_brace}Ni/Bpe/VO{r_brace} systems (4,4'-bipyridine (Bpy), 1,2-di(4-pyridyl) ethylene (Bpe)). The vanadium coordination is partially controlled by the hydrothermal synthesis conditions, and the final crystal structures depend on the synergetic interaction between the metal-organic subnets and the vanadium oxide subunits.

  11. Synthesis, structure and properties of decakis(phenylthio)corannulene.

    Science.gov (United States)

    Baldridge, Kim K; Hardcastle, Kenneth I; Seiders, T Jon; Siegel, Jay S

    2010-01-07

    Decakis(phenylthio)corannulene has been prepared from decachlorocorannulene by direct nucleophilic substitution; electronic structure properties and the X-ray crystal structure were determined and compared to predictions made by ab initio quantum chemical calculations.

  12. Nickel–carbon nanocomposites: Synthesis, structural changes and strengthening mechanisms

    International Nuclear Information System (INIS)

    Nunes, D.; Vilarigues, M.; Correia, J.B.; Carvalho, P.A.

    2012-01-01

    The present work investigates Ni–nanodiamond and Ni–graphite composites produced by mechanical synthesis and subsequent heat treatments. Processing of nickel–carbon nanocomposites by this powder metallurgy route poses specific challenges, as carbon phases are prone to carbide conversion and amorphization. The processing window for carbide prevention has been established through X-ray diffraction by a systematic variation of the milling parameters. Transmission electron microscopy confirmed the absence of carbide and showed homogeneous particle distributions, as well as intimate bonding between the metallic matrix and the carbon phases. Ring diffraction patterns of chemically extracted carbon phases demonstrated that milled nanodiamond preserved crystallinity, while an essentially amorphous nature could be inferred for milled graphite. Raman spectra confirmed that nanodiamond particles remained largely unaffected by mechanical synthesis, whereas the bands of milled graphite were significantly changed into the typical amorphous carbon fingerprint. The results on the annealed nanocomposites showed that milling with Ni accelerated graphitization of the carbon phases during heat treatments at 973 and 1073 K in both composites. At the finer scales, the nanocomposites exhibited a remarkable microhardness enhancement (∼70%) compared with pure nanostructured nickel. The Hall–Petch relation and the Orowan–Ashby equation are used to discuss strengthening mechanisms and the load transfer ability to the reinforcing particles.

  13. Synthesis, structure and Hirshfeld surface analysis, vibrational and ...

    Indian Academy of Sciences (India)

    2.2 Crystal data and structure determination. For the structural study we chose a crystal with the dimen- sions of 0.31 × 0.28 × 0.19 mm3. The single crystal was fixed on a Bruker APEXII CCD four-circle diffractometer;. MoKα radiation (λ = 0.71073 Ε) was used in order to study its structural analysis. The crystal structure has ...

  14. Synthesis, crystal structure and Thermogravimetry of ortho-phthalic ...

    Indian Academy of Sciences (India)

    The unit cell structure of the complex is shown in figure 3. The structure shows that the butoxy group from the ligand is lost during the formation of the complex and phthalic acid acts as a bridging ligand in the com- plex. Each Cu(II) ion is coordinated with four phtha- late ligands completing an octahedral structure with six.

  15. Synthesis, structure and luminescence properties of phosphates A1 ...

    Indian Academy of Sciences (India)

    rule and the localization of this cation in the structure, which is in agreement with the structural characterization. It appears that europium ... 1. Introduction. Atom isomorphism in complex crystalline compounds with ..... isotropic approx- imation of basis atom positions in the structures of phosphates Na0.7Eu0.1Zr2(PO4)3 and.

  16. Synthesis and crystal structure of a wheel-shaped supramolecular ...

    Indian Academy of Sciences (India)

    elucidation of the structure of the final product. The details of the structural parameters and the non-covalent ... tra for 1 and the bulk product were recorded on a. Bruker AMX-400 FT-NMR spectrometer. ICPMS was .... certed fashion to complete the ring structure (figure 2).6. Examples of metal-based trigonal-prisms were ...

  17. Optical and electrochemical properties of CeO{sub 2} thin film prepared by an alkoxide route

    Energy Technology Data Exchange (ETDEWEB)

    Avellaneda, Cesar O. [Departamento de Quimica - LIEC, Universidade Federal de Sao Carlos, C.P. 676, CEP 13565-905, Sao Carlos, SP (Brazil); Berton, Marcos A.C. [Departamento de Tecnologia de Materiais, Instituto de Tecnologia para o Desenvolvimento - LACTEC, C.P. 19067, CEP 81531-990, Curitiba, PR (Brazil); Bulhoes, Luis O.S. [Departamento de Quimica - LIEC, Universidade Federal de Sao Carlos, C.P. 676, CEP 13565-905, Sao Carlos, SP (Brazil); CENIP, Centro Universitario Central Paulista - UNICEP, Rua Miguel Petroni 5111, CEP 13563-470, Sao Carlos, SP (Brazil)

    2008-02-15

    Transparent CeO{sub 2} thin solid films, used as ion storage layer in electrochromic devices were prepared by the sol-gel method using an alkoxide route combined with the dip-coating technique. The precursor sol was prepared from a mixture of cerium (IV) methoxyethoxide in anhydrous 2-butanol. Electrochemical Li{sup +} intercalation/deintercalation was performed by cyclic voltammetry and the results indicate that the CeO{sub 2}/LiClO{sub 4} system is electrochemically reversible. The total inserted/extracted charge of the CeO{sub 2} film was determined by chronoamperometric measurements, which showed an ion storage capacity of {proportional_to}14 mC/cm{sup 2}. The solid-state diffusion of lithium ion into the CeO{sub 2} thin films was investigated by electrochemical impedance spectroscopy. (author)

  18. Minute-made and low carbon fingerprint microwave synthesis of high quality templated mesoporous silica

    KAUST Repository

    Chaignon, J.

    2015-01-01

    © The Royal Society of Chemistry 2015. Hexagonal mesostructured templated silicas were produced in less than 10 minutes using an ultra-fast microwave assisted hydrothermal synthesis. Typically, 10 g can be prepared at once in a commercial microwave device usually devoted to analytical digestion. Undesired alcohol side-products were avoided using inexpensive water colloidal silica instead of silicon alkoxides as the silicon source. In comparison with classical heating activation, the absence of pore expansion and pore wall thickening even for synthesis temperatures as high as 190 °C evidenced that heat transfer and diffusion of matter had no time to take place. Comparison between the chemically extracted and calcined samples shows that the structure was better stabilized for autoclaving above 150 °C. However, a fast temperature ramping and final temperatures above 180 °C were required to sear structures of the highest quality comparable to that of the best conventional methods. This is rationalized by assuming a sequential flake-by-flake assembly of the pore-wall at the micelle palisade. Notably, tosylate counterions yielded better structural characteristics than bromide counterions and allowed better opportunities for surfactant recycling.

  19. Synthesis and characterization of Al-TON zeolite using a dialkylimizadolium as structure-directing agent

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Christian Wittee; Pergher, Sibele Berenice Castella, E-mail: chriswittee@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Villarroel-Rocha, Jhonny [Laboratorio de Solidos Porosos, Instituto de Fisica Aplicada, Universidad Nacional de San Luis, Chacabuco, San Luis (Argentina); Silva, Bernardo Araldi Da; Mignoni, Marcelo Luis [Universidade Regional Integrada, Erechim, RS (Brazil)

    2016-11-15

    In this work, the synthesis of zeolites using 1-butyl-3-methylimidazolium chloride [C{sub 4}MI]Cl as a structure-directing agent was investigated. The organic cation shows effectiveness and selectivity for the syntheses of TON zeolites under different reaction conditions compared to the traditional structure directing agent, 1,8-diaminooctane. The 1-butyl-3-methylimidazolium cation lead to highly crystalline materials and its role as OSDA in our synthesis conditions has been confirmed by characterization techniques. ICP-OES confirms the presence of Al in the samples and {sup 27}Al MAS NMR analysis indicated that aluminum atoms were incorporated in tetrahedral coordination. Scanning electron microscopy indicated that changing the crystallization condition (static or stirring), zeolites with different crystal size were obtained, which consequently affects the textural properties of the zeolites. Moreover, varying some synthesis parameters MFI zeolite can also be obtained. (author)

  20. Synthesis and structural characterization of manganese olivine lithium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Herrera Robles, Joel O. [Basic Science Department, IIT, Universidad Autónoma de Ciudad Juárez, Av. del Charro 460 norte Cd. Juárez, Chih. C.P. 32310 (Mexico); Fuentes Cobas, Luis E. [Centro de Investigación en Materiales Avanzados CIMAV, Complejo Industrial, M. Cervantes 120, Chihuahua C.P. 31109 (Mexico); Díaz de la Torre, Sebastián [Instituto Politécnico Nacional, Centro de Investigación e Innovación Tecnológica CIITEC, Azcapotzalco, México, D.F. C.P. 02250 (Mexico); Camacho Montes, Héctor, E-mail: hcamacho@uacj.mx [Basic Science Department, IIT, Universidad Autónoma de Ciudad Juárez, Av. del Charro 460 norte Cd. Juárez, Chih. C.P. 32310 (Mexico); Elizalde Galindo, José T.; García Casillas, Perla E.; Rodríguez González, Claudia A. [Basic Science Department, IIT, Universidad Autónoma de Ciudad Juárez, Av. del Charro 460 norte Cd. Juárez, Chih. C.P. 32310 (Mexico); Álvarez Contreras, Lorena [Centro de Investigación en Materiales Avanzados CIMAV, Complejo Industrial, M. Cervantes 120, Chihuahua C.P. 31109 (Mexico)

    2015-09-15

    Highlights: • LiMnPO{sub 4} was obtained by sol gel method and crystallization in reducing atmosphere. • Magnetic and electric properties are reported for LiMnPO{sub 4}. • Electrochemical properties are also found and enhanced by adding carbon. • SEM and HRTEM show the submicron powder nature. • The multifunctional behavior of LiMnPO{sub 4} is experimentally demonstrated. - Abstract: The manganese olivine lithium phosphate is a multifunctional material. If carbon is added to form a composite LiMnPO{sub 4}–C, electrochemical properties can be enhanced, making this material a good candidate for battery cathode. High magnetic susceptibility is reported for this compound at room temperature. In this work, the magnetic response was measured through a Field Cooling/Zero Field Cooling technique at temperature below 100 K. Weak ferroelectric properties at room temperature were measured. Even though, the promising applications and the interesting properties of this system, the attention received in the literature is relatively low. The synthesis of this material is difficult because of the rapid manganese oxidation and the need of a reducing atmosphere. In fact, only few authors report the synthesis of the pure phase. In the present work, nanostructured LiMnPO{sub 4} is obtained by sol gel chemical method and according to X-ray diffraction patterns, pure LiMnPO{sub 4} is obtained after calcination in a reducing atmosphere (10% H{sub 2} – 90% Ar). Nanostructured LiMnPO{sub 4} is a material with very interesting properties that deserves attentions.

  1. Stop Flow Lithography Synthesis and Characterization of Structured Microparticles

    Directory of Open Access Journals (Sweden)

    David Baah

    2014-01-01

    Full Text Available In this study, the synthesis of nonspherical composite particles of poly(ethylene glycol diacrylate (PEG-DA/SiO2 and PEG-DA/Al2O3 with single or multiple vias and the corresponding inorganic particles of SiO2 and Al2O3 synthesized using the Stop Flow Lithography (SFL method is reported. Precursor suspensions of PEG-DA, 2-hydroxy-2-methylpropiophenone, and SiO2 or Al2O3 nanoparticles were prepared. The precursor suspension flows through a microfluidic device mounted on an upright microscope and is polymerized in an automated process. A patterned photomask with transparent geometric features masks UV light to synthesize the particles. Composite particles with vias were synthesized and corresponding inorganic SiO2 and Al2O3 particles were obtained through polymer burn-off and sintering of the composites. The synthesis of porous inorganic particles of SiO2 and Al2O3 with vias and overall dimensions in the range of ~35–90 µm was achieved. BET specific surface area measurements for single via inorganic particles were 56–69 m2/g for SiO2 particles and 73–81 m2/g for Al2O3 particles. Surface areas as high as 114 m2/g were measured for multivia cubic SiO2 particles. The findings suggest that, with optimization, the particles should have applications in areas where high surface area is important such as catalysis and sieving.

  2. Controlled Synthesis of Ultralong Carbon Nanotubes with Perfect Structures and Extraordinary Properties.

    Science.gov (United States)

    Zhang, Rufan; Zhang, Yingying; Wei, Fei

    2017-02-21

    Carbon nanotubes (CNTs) have drawn intensive research interest in the past 25 years due to their excellent properties and wide applications. Ultralong CNTs refers to the horizontally aligned CNT arrays which are usually grown on flat substrates, parallel with each other with large intertube distances. They usually have perfect structures, excellent properties, and lengths up to centimeters, even decimeters. Ultralong CNTs are promising candidates as building blocks for transparent displays, nanoelectronics, superstrong tethers, aeronautics and aerospace materials, etc. The controlled synthesis of ultralong CNTs with perfect structures is the key to fully exploit the extraordinary properties of CNTs. CNTs are typical one-dimensional single-crystal nanomaterials. It has always been a great challenge how to grow macroscale single-crystals with no defects. Thus, the synthesis of ultralong CNTs with no defect is of significant importance from both fundamental and industrial aspects. In this Account, we focus on our progress on the controlled synthesis of ultralong CNTs with perfect structures and excellent properties. A deep understanding of the CNT growth mechanism is the first step for the controlled synthesis of ultralong CNTs with high quality. We first introduce the growth mechanism for ultralong CNTs and the main factor affecting their structures. We then discuss the strategies to control the defects in the as-grown ultralong CNTs. With these approaches, ultralong high-quality CNTs with different structures can be obtained. By completely eliminating the factors which may induce defects in the CNT walls, ultralong CNTs with perfect structures can be obtained. Their chiral indices keep unchanged for several centimeters long along the axial direction of the CNTs. The defect-free structures render the ultralong CNTs with excellent electrical, mechanical and thermal properties. The as-grown ultralong CNTs exhibit superhigh mechanical strength (>100 GPa) and their

  3. Metal-Metal Bonds and Metal Carbon Bonds in the Chemistry of Molybdenum and Tungsten Alkoxides.

    Science.gov (United States)

    1983-02-07

    isopropoxy and neopentoxy compounds are oligomers [MoO 2(OR)21 n of, as yet, unknown struc- 2_no, syt unkow stuc 34 tures. A clean synthesis of the latter...to green solutions containing the triangulo Mo 30(OR)to compounds (see Figure 5). A clean, direct synthesis of these compounds is by the addition of...Also, the W-O distances associated with the W 2( 2-OPri) 2 group are asymetric , averaging 1.92 X and 2.10 X to W(1) and W(2), respectively. The

  4. Synthesis and structural studies of half-sandwich Cp* rhodium and ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 5. Synthesis and structural studies of half-sandwich Cp* rhodium and Cp* iridium complexes featuring mono, bi and tetradentate nitrogen and oxygen donor ligands. NARASINGA RAO PALEPU WERNER KAMINSKY MOHAN RAO KOLLIPARA. Regular ...

  5. [3.3]Dithia-bridged cyclophanes featuring a thienothiophene ring : synthesis, structures and conformational analysis

    NARCIS (Netherlands)

    Mashraqui, Sabir H.; Sanghvikar, Yogesh; Ghadhigaonkar, Shailesh; Kumar, Sukeerthi; Meetsma, Auke; Dau, Elise Tran Huu

    2009-01-01

    The synthesis of [3.3]dithia-bridgedcyclophanes 7, 9 and 11 incorporating a fused heterocycle, thieno[2,3-b] thiophene is described. The structures are established by H-1 NMR analysis and, in the case of 11, also by single crystal X-ray crystallography. Conformational analysis by variable

  6. Synthesis, Structure and Antioxidant Activity of Cyclohexene-Fused Selenuranes and Related Derivatives

    Directory of Open Access Journals (Sweden)

    Poonam Rajesh Prasad

    2015-07-01

    Full Text Available Synthesis, structure and antioxidant activity of new cyclohexene-fused spiroselenuranes and a spirotellurane is reported. Oxidation reactions of bis(o-formylcyclohex- 1-eneselenide/bis(2-hydroxymethylcyclohex-1-eneselenide provide the corresponding spiroselenuranes. The glutathione peroxidase-like activity of the newly synthesized compounds has been evaluated.

  7. Synthesis of PbTe nanocubes, worm-like structures and ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 5. Synthesis of PbTe nanocubes, worm-like structures and nanoparticles by simple thermal evaporation method. L Kungumadevi ... Sathyamoorthy1. PG and Research Department of Physics, Kongunadu Arts and Science College, Coimbatore 641 029, India ...

  8. Synthesis, molecular structures and ESI-mass studies of copper (I ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 10. Synthesis, molecular structures and ESI-mass studies of copper(I) complexes with ligands incorporating N, S and P donor atoms. Tarlok S Lobana Arvinder Kaur Rohit Sharma Madhu Bala Amanpreet K Jassal Courtney E Duff Jerry P Jasinski. Volume ...

  9. Seeking Polymeric Prodrugs of Norfloxacin. Part 2. Synthesis and Structural Analysis of Polyurethane Conjugates

    Directory of Open Access Journals (Sweden)

    Waclaw Kolodziejski

    2010-02-01

    Full Text Available Oligo(ε-caprolactone and oligolactide were synthesized via ring-opening polymerization of cyclic esters in the presence of creatinine as initiators. Thus obtained oligomers were successfully used in the synthesis of novel polyurethane conjugates of norfloxacin. The structures of the polymers and conjugates were elucidated by means of MALDI-TOF MS, NMR and IR studies.

  10. Synthesis, crystal structure and photo luminescent property of a 3D ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 125; Issue 3. Synthesis, crystal structure and photo luminescent property of a 3D metal-organic hybrid of Cd(II) constructed by two different bridging carboxylate. Biswajit Bhattacharya Rajdip Dey Debajyoti Ghoshal. Volume 125 Issue 3 May 2013 pp 661-666 ...

  11. Aircraft interior noise prediction using a structural-acoustic analogy in NASTRAN modal synthesis

    Science.gov (United States)

    Grosveld, Ferdinand W.; Sullivan, Brenda M.; Marulo, Francesco

    1988-01-01

    The noise induced inside a cylindrical fuselage model by shaker excitation is investigated theoretically and experimentally. The NASTRAN modal-synthesis program is used in the theoretical analysis, and the predictions are compared with experimental measurements in extensive graphs. Good general agreement is obtained, but the need for further refinements to account for acoustic-cavity damping and structural-acoustic interaction is indicated.

  12. Synthesis, structural and dielectric properties of 0.8 PMN–0.2 PT ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 5. Synthesis, structural and dielectric ... S A BAND2. Department of Physics, J D College Of Engineering and Management (JDCOEM), Nagpur 441501, India; Department of Physics, Yeshwantrao Chavan College of Engineering, Nagpur 441110, India ...

  13. Synthesis, X-ray structure and N–H…O interactions in 1,3-diphenyl ...

    Indian Academy of Sciences (India)

    The synthesis, X-ray structure and role of intermolecular interactions have been studied in case of 1,3-diphenyl-urea, owing to its medicinal importance. The compound crystallizes in orthorhombic crystal system (space group, 21) with unit cell parameters, = 9.118(3), = 10.558(2), = 11.780(3) Å and = 4.

  14. Synthesis and molecular structure of chiral metallo-based sterically overcrowded alkenes

    NARCIS (Netherlands)

    Wiel, Matthijs K.J. ter; Meetsma, Auke; Feringa, Bernard

    2002-01-01

    A four step synthesis of pyridyl-2-yl-thioxanthen-9-ylidene-isoquinolines is described. The corresponding palladium complexes are the first examples of a novel class of chiral, metallo-based, sterically overcrowded alkenes. The crystal and molecular structure of the palladium dichloride complex

  15. Synthesis, X-ray structure and N–H…O interactions in 1,3-diphenyl ...

    Indian Academy of Sciences (India)

    Unknown

    the synthesis and structural investigations of 1,3-diphenyl- urea have been undertaken. The title compound has been expected to be an excellent potential tyrosine phosphatase inhibitor and sickle-cell anemia treatment drug. 2. Experimental. A mixture of phenylisocyanate, 1⋅07 g (0⋅01 mole), aniline,. 0⋅94 g (0⋅01 mole) ...

  16. Synthesis and crystal structure determination of YCo Fe O 3 (= 0 ...

    Indian Academy of Sciences (India)

    The results on synthesis, crystal structure determination and calculation of crystallochemical parameters of YCo1−FeO3 ( = 0, 0.33, 0.5, 0.67 and 1) perovskites are presented in this work. The compounds within this series were synthesized by solution combustion method using two different fuels: urea and citric acid.

  17. Tubular duplex alpha-cyclodextrin triply bridged with disulfide bonds: synthesis, crystal structure and inclusion complexes

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Lucie; Buděšínský, Miloš; Císařová, I.; Kraus, Tomáš

    -, č. 24 (2009), s. 3557-3559 ISSN 1359-7345 R&D Projects: GA AV ČR IAA400550810; GA ČR GA203/06/1550; GA MŠk OC 172 Institutional research plan: CEZ:AV0Z40550506 Keywords : cyclodextrines * synthesis * crystal structure Subject RIV: CC - Organic Chemistry Impact factor: 5.504, year: 2009

  18. Fixation of CO2 in air: Synthesis and crystal structure of a µ3-CO3 ...

    Indian Academy of Sciences (India)

    Unknown

    *For correspondence. Fixation of CO2 in air: Synthesis and crystal structure of a. µ3-CO3-bridged tricopper(II) compound. JHUMPA MUKHERJEEa, V BALAMURUGANa, MANINDER SINGH HUNDALb and. RABINDRANATH MUKHERJEEa,*. aDepartment of Chemistry, Indian Institute of Technology, Kanpur 208 016, India.

  19. SYNTHESIS AND STRUCTURAL ANALYSES OF BIS(2-OXO-2,3 ...

    African Journals Online (AJOL)

    SYNTHESIS AND STRUCTURAL ANALYSES OF BIS(2-OXO-2,3-. DIHYDROPYRIMIDIN-1-IUM) TETRACHLORO ZINCATE (II). [H2pymo][ZnCl4] AND BIS(PYRIMIDIN-2-OLATE) ZINC(II). [Zn(PYMO)2]. Mukhtar A. Kurawa. Department of Pure and Industrial Chemistry, Bayero University Kano. P. M. B. 3011 Kano Nigeria.

  20. Synthesis, structure analysis, anti-bacterial and in vitro anti-cancer ...

    Indian Academy of Sciences (India)

    DOI 10.1007/s12039-015-0824-z. Synthesis, structure analysis, anti-bacterial and in vitro anti-cancer activity of new Schiff base and its copper complex derived from sulfamethoxazole. I RAMA∗ and R SELVAMEENA. PG and Research Department of Chemistry, Seethalakshmi Ramaswami College,. Tiruchirappalli 620 002 ...

  1. In silico structure-based design and synthesis of novel anti-RSV compounds

    NARCIS (Netherlands)

    Cancellieri, Michela; Bassetto, Marcella; Widjaja, Ivy; van Kuppeveld, Frank; de Haan, Cornelis A M; Brancale, Andrea; de Haan, C.A.M.

    2015-01-01

    Respiratory syncytial virus (RSV) is the major cause for respiratory tract disease in infants and young children. Currently, no licensed vaccine or a selective antiviral drug against RSV infections are available. Here, we describe a structure-based drug design approach that led to the synthesis of a

  2. Synthesis and structure of D3h-symmetric triptycene trimaleimide

    NARCIS (Netherlands)

    Zonta, C.; De Lucchi, O.; Linden, Anthony; Lutz, M.

    2010-01-01

    A new D3h symmetric triptycene derivative has been synthesized with the aim of obtaining molecules that are able to assemble into porous structures, and can be used in the development of new ligands. The synthesis involves a Diels-Alder reaction as the key step, followed by an oxidation and the

  3. Origami-inspired active structures: a synthesis and review

    International Nuclear Information System (INIS)

    Peraza-Hernandez, Edwin A; Hartl, Darren J; Malak Jr, Richard J; Lagoudas, Dimitris C

    2014-01-01

    Origami, the ancient art of paper folding, has inspired the design of engineering devices and structures for decades. The underlying principles of origami are very general, which has led to applications ranging from cardboard containers to deployable space structures. More recently, researchers have become interested in the use of active materials (i.e., those that convert various forms of energy into mechanical work) to effect the desired folding behavior. When used in a suitable geometry, active materials allow engineers to create self-folding structures. Such structures are capable of performing folding and/or unfolding operations without being kinematically manipulated by external forces or moments. This is advantageous for many applications including space systems, underwater robotics, small scale devices, and self-assembling systems. This article is a survey and analysis of prior work on active self-folding structures as well as methods and tools available for the design of folding structures in general and self-folding structures in particular. The goal is to provide researchers and practitioners with a systematic view of the state-of-the-art in this important and evolving area. Unifying structural principles for active self-folding structures are identified and used as a basis for a quantitative and qualitative comparison of numerous classes of active materials. Design considerations specific to folded structures are examined, including the issues of crease pattern identification and fold kinematics. Although few tools have been created with active materials in mind, many of them are useful in the overall design process for active self-folding structures. Finally, the article concludes with a discussion of open questions for the field of origami-inspired engineering. (topical review)

  4. Synthesis, crystal structure and Thermogravimetry of ortho-phthalic ...

    Indian Academy of Sciences (India)

    Abstract. Coordination polymer of Cu(II) bridged by o-phthalic acid alone is not known. The reaction of. CuCl2.2H2O with (2-butoxycarbonyl)benzoic acid yielded three dimensional coordination polymer bridged by o-phthalic acid. X-ray crystal structure shows structure with monoclinic P21/c space group. o-Phthalic acid.

  5. Synthesis, structure and thermoelectric properties of La1 ...

    Indian Academy of Sciences (India)

    Structural parameters for all the compounds were confirmed by the Rietveld refinement method usingpowder X-ray diffraction (XRD) data and exhibit the rhombhohedral crystal structure with space group R-3c (No. 167). Thescanning electron microscopy study reveals that the particles are spherical in shape and sizes, in the ...

  6. Synthesis, reactivity and structural studies of carboranyl thioethers and disulfides

    Czech Academy of Sciences Publication Activity Database

    Laromaine, A.; Teixidor, F.; Kivekäs, R.; Sillanpää, R.; Benakki, R.; Grüner, Bohumír; Vinas, C.

    -, č. 10 (2005), s. 1785-1795 ISSN 1477-9226 Grant - others:Generalitat de Catalunya(ES) 2001/SGR/0033 Keywords : molecular structure * crystal structure * closo-carboranes Subject RIV: CA - Inorganic Chemistry Impact factor: 3.003, year: 2005

  7. Synthesis, structure and Hirshfeld surface analysis, vibrational and ...

    Indian Academy of Sciences (India)

    Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular surfacecontours and 2D fingerprint plots has been used to scrutinize molecular shapes. The vibration properties of this structure were studied by IR spectroscopy and Raman scattering. Vibration spectra ...

  8. Solid state synthesis and structural refinement of polycrystalline La ...

    Indian Academy of Sciences (India)

    Perovskite structure based ceramic precursors have a characteristic property of substitution in the ``A" site of the ABO3 structure. This makes them a potential material for nuclear waste management in synthetic rock (SYNROC) technology. In order to simulate the mechanism of rare earth fixation in perovskite, La ...

  9. Synthesis of nano structures for use as toxic gas adsorbents

    International Nuclear Information System (INIS)

    Velazquez P, S.; Pacheco S, J.; Estrada M, N.; Vasquez N, C.; Garcia R, M.; Garduno A, M.; Torres R, C.; Garcia G, J.; Pacheco P, M.; Valdivia B, R.; Ramos F, F.; Cruz A, A.; Duran G, M.; Hidalgo P, M.

    2008-01-01

    The work described here is the study of adsorption of nitrogen oxides by carbon nano structures and its implementation in a plasma reactor used to treat toxic gases. By placing a bed of carbon nano structures to the plasma reactor outlet obtained and increase in the efficiency of degradation. (Author)

  10. Synthesis, crystal structure, optical and electrochemical properties of ...

    Indian Academy of Sciences (India)

    Its molecular geometry in the ground state has also been calculated using density functional theory (DFT) at the B3LYP/6-31G∗∗ level and compared with its crystal structure. Results show that the optimized geometry can well reproduce the crystal structure. Furthermore, both absorption and emission spectra of 1 and 2 ...

  11. Bureaucratic Structure in Schools: A Refinement and Synthesis in Measurement.

    Science.gov (United States)

    Sousa, David A.; Hoy, Wayne K.

    1981-01-01

    Compares two methods of measuring bureaucratic structure, Hall's organizational inventory and the University of Aston (England) approach, and tests them using data from 55 public high schools in New Jersey. Factor analysis reveals four underlying dimensions of school structure, including organizational control, rational specialization, system…

  12. Synthesis, Structure and Hirshfeld surface analysis, vibrational and ...

    Indian Academy of Sciences (India)

    3

    lead to the formation of a three-dimensional architecture. Hirshfeld surface analysis for visually analyzing intermolecular interactions in crystal structures employing molecular surface contours and 2D fingerprint plots have been used to scrutinize molecular shapes. The vibration properties of this structure were studied by IR ...

  13. Hydrolytic activity of μ-alkoxide/acetato-bridged binuclear Cu(II ...

    Indian Academy of Sciences (India)

    Design and synthesis of artificial hydrolases towards esterolysis received considerable attention due to its ... the decrease in reaction activation energy besides cre- ating a high effective concentration resulting in high .... of a given concentration was almost completely hydro- lysed at 3 min intervals. The obtained half-lives ...

  14. Synthesis and crystal structure of trans-[Ni(pyzdcH)M 2 (H 2 O) 2 ...

    African Journals Online (AJOL)

    Synthesis and crystal structure of trans-[Ni(pyzdcH)M 2 (H 2 O) 2 ] based on pyrazine-2,3-dicarboxylic acid. ... Bulletin of the Chemical Society of Ethiopia ... The determined structure of the title compound C24H20Ni2N8O20 consists of the mononuclear trans-[Ni(pyzdc)2(H2O)2], (pyzdc = pyrazine-2,3- dicarboxylate).

  15. Synthesis of gold nanoparticles with different atomistic structural characteristics

    International Nuclear Information System (INIS)

    Esparza, R.; Rosas, G.; Lopez Fuentes, M.; Sanchez Ramirez, J.F.; Pal, U.; Ascencio, J.A.; Perez, R.

    2007-01-01

    A chemical reduction method was used to produce nanometric gold particles. Depending on the concentration of the main reactant compound different nanometric sizes and consequently different atomic structural configurations of the particles are obtained. Insights on the structural nature of the gold nanoparticles are obtained through a comparison between digitally-processed experimental high-resolution electron microscopy images and theoretically-simulated images obtained with a multislice approach of the dynamical theory of electron diffraction. Quantum molecular mechanical calculations, based on density functional theory, are carried out to explain the relationships between the stability of the gold nanoparticles, the atomic structural configurations and the size of nanoparticles

  16. Synthesis, structure and Hirshfeld surface analysis, vibrational and ...

    Indian Academy of Sciences (India)

    dimensional architecture. Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular sur- face contours and 2D fingerprint plots has been used to scrutinize molecular shapes. The vibration ...

  17. Synthesis and molecular structure of manganese complexes with ...

    Indian Academy of Sciences (India)

    Administrator

    Manganese-dioxygen complexes are assumed to play significant roles in physiologically important enzymatic reactions including superoxide dismutation, decomposition of hydrogen peroxide and dioxygen evolution from water catalysed by manganese containing proteins 1. Accordingly, the characterization of structurally ...

  18. "Chameleon" Macromolecules: Synthesis, Structures and Applications of Stimulus Responsive Polymers

    NARCIS (Netherlands)

    Sui, Xiaofeng

    2012-01-01

    This thesis describes the preparation and characterization of addressable responsive polymer structures and their versatile applications. Stimuli responsive polymer chains including temperature responsive poly(N-isopropylacrylamide), PNIPAM, pH responsive poly(methacrylic acid), PMAA and redox

  19. Carbothermal synthesis of ZnO nanocomb structure

    International Nuclear Information System (INIS)

    Lim, Y.S.; Park, J.W.; Hong, S.-T.; Kim, J.

    2006-01-01

    A study on the formation and characterization of ZnO nanocomb structure is presented. ZnO nanocomb was synthesized by the carbothermal reduction process with carbon black powder as a carbon source. As well as nanocomb, ZnO tetrapod and flower-like structures were also obtained in this experiment. When conventional graphite was used for a comparative study, no ZnO nanostructure could be achieved at the same experimental condition. The result shows that carbon source with large surface area more efficiently provides Zn (g) by the enhanced solid-solid reaction between C (s) and ZnO (s) source materials. The resulting ZnO structures were characterized with an X-ray diffractometer (XRD), a scanning electron microscopy (SEM), and a transmission electron microscopy (TEM), and the formation mechanism of nanocomb structure was discussed

  20. Synthesis, characterization, x-ray structure and antimicrobial activity ...

    African Journals Online (AJOL)

    Purpose: To synthesize thiosemicarbazide and determine its antimicrobial properties. Methods: Pyridine-based thiosemicarbazide was synthesized, characterized and evaluated for antimicrobial activity. The structure of the synthesized compound was established by spectral analysis, namely, Fourier transform infrared ...

  1. Synthesis, crystal structures and luminescence properties of two metal carboxyphosphonates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chaonan; Feng, Pingjing; Li, Jintang, E-mail: leejt@xmu.edu.cn; Luo, Xuetao

    2017-05-15

    Two metal carboxyphosphonates, [Co{sub 2}(OOCC{sub 5}H{sub 3}NPO{sub 3}){sub 2·}(H{sub 2}O){sub 3}] (Compound1) and Zn{sub 3}[OOCC{sub 6}H{sub 3}CH(OH)PO{sub 3}]{sub 2·}2H{sub 2}O (Compound2) were successfully synthesized under the hydrothermal reactions. In compound 1, two (Co1-NO{sub 5}) octahedra link the (CPO{sub 3}) by sharing the corner, which link the two (Co2-O{sub 6}) octahedra. From a-axis the six clusters form the layer. Each layer is linked through hydrogen bond. In compound 2, the (Zn-O{sub 4}) tetrahedron and (CPO{sub 3}) tetrahedron are corner-shared, which arrange in line. From a-axis, each line forms the columnar. The thermal and luminescence properties of these compounds were investigated. - Graphical abstract: The synthesis conditions of the two compounds and the crystal morphology. Compound 1 shows the layer and the compound 2 shows the pillared-layer. - Highlights: • Two new carboxyphosphonate ligands have been prepared. • Using the two ligands, two metal carboxyphosphonates have been synthesized. • The two MOFs may be candidates for fluorescent materials.

  2. Oxidative tandem alkoxide conjugate addition to nitroalkenes/radical 5-exo cyclizations-a versatile synthesis of functionalized 3-nitrotetrahydrofurans

    Czech Academy of Sciences Publication Activity Database

    Jahn, Ullrich; Rudakov, D.; Jones, P. G.

    2012-01-01

    Roč. 68, č. 5 (2012), s. 1521-1539 ISSN 0040-4020 Institutional research plan: CEZ:AV0Z40550506 Keywords : electron transfer * tandem reaction * tetrahydrofurans * oxidation * radicals Subject RIV: CC - Organic Chemistry Impact factor: 2.803, year: 2012

  3. Anionic polymerization of acrylates. XIV. Synthesis of MMA/acrylate block copolymers initiated with ester-enolate/tert-alkoxide complex

    Czech Academy of Sciences Publication Activity Database

    Vlček, Petr; Čadová, Eva; Kříž, Jaroslav; Látalová, Petra; Janata, Miroslav; Toman, Luděk; Masař, Bohumil

    2005-01-01

    Roč. 46, č. 14 (2005), s. 4991-5000 ISSN 0032-3861 Institutional research plan: CEZ:AV0Z4050913 Keywords : ligated anionic polymerization * (meth)acrylates * block copolymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.849, year: 2005

  4. Coprecipitation synthesis and negative thermal expansion of NbVO5.

    Science.gov (United States)

    Wang, Jinrui; Deng, Jinxia; Yu, Ranbo; Chen, Jun; Xing, Xianran

    2011-04-07

    We develop a coprecipitation synthesis route to prepare NbVO(5) with simple oxide Nb(2)O(5) and NH(4)VO(3) as starting materials. No metal alkoxide or organometallic substance was used in the process. Nano-crystal NbVO(5) was obtained by calcination of the coprecipitates at 550 °C for 2 h. DSC/TG and XRD investigations indicate that the target compound NbVO(5) is completely formed up to 504.5 °C and is thermally stable below 658 °C. Rietveld XRD refinements give an orthorhombic structure with space group Pnma and lattice parameters, a=11.8453(2), b=5.5126(3) and c=6.9212(2) Å, respectively. In particular, HTXRD determinations show a negative thermal expansion in NbVO(5) with a TEC of -6.63 × 10(-6) °C(-1) in the temperature range of RT-600 °C. This fact is ascribed to the tilting of NbO(6) octahedra and VO(4) tetrahedra in the flexible framework structure. The present synthesis route is facile and easy to be extended to prepare analogues such as TaVO(5), etc. © The Royal Society of Chemistry 2011

  5. Structural diversity and chemical synthesis of peroxide and peroxide-derived polyketide metabolites from marine sponges.

    Science.gov (United States)

    Norris, Matthew D; Perkins, Michael V

    2016-07-28

    Covering: up to early 2016Marine sponges are widely known as a rich source of natural products, especially of polyketide origin, with a wealth of chemical diversity. Within this vast collection, peroxide and peroxide-derived secondary metabolites have attracted significant interest in the fields of natural product isolation and chemical synthesis for their structural distinction and promising in vitro antimicrobial and anticancer properties. In this review, peroxide and peroxide-derived polyketide metabolites isolated from marine sponges in the past 35 years are summarised. Efforts toward their synthesis are detailed with a focus on methods that utilise or attempt to elucidate the complex biosynthetic interrelationships of these compounds beyond enzymatic polyketide synthesis. Recent isolations, advances in synthetic methodology and theories of biogenesis are highlighted and critically evaluated.

  6. Synthesis, crystal structure and biological activity of novel diester cyclophanes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengfei; Yang, Bingqin; Fang, Xianwen; Cheng, Zhao; Yang, Meipan, E-mail: yangbq@nwu.edu.cn [Department of Chemistry, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Northwest University, Shaanxi (China)

    2012-10-15

    A series of novel diester cyclophanes was synthesized by esterification of 1,2-benzenedicarbonyl chloride with eight different diols under high dilution conditions. The structures of the compounds were verified by elemental analysis, {sup 1}H nuclear magnetic resonance (NMR), IR spectroscopy and high resolution mass spectrometry (HRMS). The crystal structures of two compounds were characterized by single crystal X-ray diffractometry (XRD). All the new cyclophanes were evaluated for biological activities and the results showed that some of these compounds have low antibacterial or antifungal activities (author)

  7. Synthesis, structure and electrical properties of the thallium ruthenate pyrochlores

    International Nuclear Information System (INIS)

    Kanno, Ryoji; Haung, Jinfan; Sleight, A.W.

    1993-01-01

    The thallium ruthenate pyrochlores, Tl 2 Ru 2 O 7-δ , were synthesized and their structures were determined by neutron diffraction measurements. The low-temperature (LT) and high-temperature (HT) phases were obtained at reaction temperatures of 500 and 900degC, respectively. Neutron diffraction measurements indicated the compositions of Tl 2 Ru 2 O 7 and Tl 2 Ru 2 O 6.71 for the HT phase and the LT phase, respectively. Electrical resistivity measurements showed metallic property for the HT phase and semiconducting property for the LT phase. The relationship between the electrical properties and the structural changes is discussed. (author)

  8. An approach to analyzing synthesis, structure and properties of bismuth titanate ceramics

    Directory of Open Access Journals (Sweden)

    Lazarević Z.

    2005-01-01

    Full Text Available The family of bismuth titanate, Bi4Ti3O12 (BIT layered-structured ferroelectrics materials is attractive from the viewpoint of their application as electronic materials such as dielectrics, piezoelectrics and pyroelectrics, because they are characterized by good stability of piezoelectric properties, a high Curie temperature and a good resistance vs temperature. Bismuth titanate (Bi4Ti3O12 powders can be prepared using different methods, depending if the creation will be film coating or ceramics. The structure and properties of bismuth titanate materials show a significance dependence on the applied synthesis method. In this review paper, we made an attempt to give an approach to analyzing the structure, synthesis methods and properties of bismuth titanate ferroelectrics materials. .

  9. Structural higher education reform - design and evaluation: synthesis report

    NARCIS (Netherlands)

    File, Jonathan M.; Huisman, Jeroen; de Boer, Harry F.; Seeber, Marco; Vukasovic, Martina; Westerheijden, Donald F.

    2016-01-01

    This study analyses how different types of system-level (or ‘landscape’) structural reforms in higher education have been designed and implemented in selected higher education systems. In the 12 case studies that form the core of the project, the researchers examine reforms aimed at: - Increasing

  10. Efficient synthesis and molecular structure of 2-hydroxyisophthaldehyde

    NARCIS (Netherlands)

    Zondervan, C; van den Beuken, E.K; Kooijman, H.; Spek, A.L.; Feringa, B.L.

    1997-01-01

    A new highly effective procedure has been developed for the preparation of 2-hydroxyisophthaldehyde from 2,6-dimethylphenol. The X-ray crystal structure shows infinite chains of molecules joined by hydrogen bonds. (C) 1997 Published by Elsevier Science Ltd.

  11. Synthesis of PbTe nanocubes, worm-like structures

    Indian Academy of Sciences (India)

    ... the optical bandgap energies of 1.61, 1.23 and 1.01 eV, respectively. Photoconductivity measurement shows that the prepared nanocrystalline PbTe thin films of different morphology exhibits good response. This structure induced change in optical properties may have potential applications in optoelectronics devices.

  12. short communication synthesis and crystal structure of a polymeric

    African Journals Online (AJOL)

    Preferred Customer

    Cg1 is the centroid of C1-C2-C3-C4-C5-C6. IR spectra of the complex. The infrared spectrum of the complex was consistent with the structure as determined by X-ray diffraction. Features corresponding to benzene ring puckering exist in the region between 820 and 600 cm-1. Asymmetric and symmetric C–O stretching.

  13. Synthesis and structural characterization of CsNiP crystal

    Indian Academy of Sciences (India)

    Unknown

    Fluck and Issleib 1965). However, studies of these alka- line metal phosphides gained momentum since last three decades (Johnson and Jeitschlo 1972; Barz et al 1983;. Muller et al 1983; Schnering et al 1999). In recent years, structural data of phosphides also were reported (Shan- non 1976; Jeitschlo and Braun 1977; ...

  14. Synthesis, crystal structure determination of two-dimensional ...

    Indian Academy of Sciences (India)

    The structure consists of 4-c uninodal net where Point symbol for Ag (I) ion and net is (44.62) with sql type topology. X-ray diffraction analysis and Hirshfeld surface analysis give rise to comparable results but in Hirshfeld surface analysis, twothird times more close contacts are obtained. The fingerprint plots demonstrate that ...

  15. Pyrene appended bile acid conjugates: Synthesis and a structure ...

    Indian Academy of Sciences (India)

    us to connect the existing gelator motifs into hybrid structures and study their gelation properties in solu- tion. We envisioned that by adding a pyrene moiety ...... seen with the simplest pyrene molecule 1-pyrene car- boxylic acid (19) or its mixture with 1-aminopyrene. (20) (prepared by heating the 1:1 mixture of the amine.

  16. Synthesis and Structure of Environmentally Relevant Perfluorinated Sulfonamides

    OpenAIRE

    Lehmler, Hans-Joachim; Rama Rao, V.V.V.N.S.; Nauduri, Dhananjaya; Vargo, John D.; Parkin, Sean

    2007-01-01

    Alkylated perfluorooctanesulfonamides are compounds of environmental concern. To make these compounds available for environmental and toxicological studies, a series of N-alkylated perfluorooctanesulfonamides and structurally related compounds were synthesized by reaction of the corresponding perfluoroalkanesulfonyl fluoride with a suitable primary or secondary amine. Perfluoroalkanesulfonamidoethanols were obtained from the N-alkyl perfluoroalkanesulfonamides either by direct alkylation with...

  17. Synthesis, structure, thermal, transport and magnetic properties of VN ceramics

    Czech Academy of Sciences Publication Activity Database

    Huber, Š.; Jankovský, O.; Sedmidubský, D.; Luxa, J.; Klimová, K.; Hejtmánek, Jiří; Sofer, Z.

    2016-01-01

    Roč. 42, č. 16 (2016), s. 18779-18784 ISSN 0272-8842 R&D Projects: GA ČR GA13-20507S Institutional support: RVO:68378271 Keywords : vanadium mononitride * phase transition * electronic structure * heat capacity * transport properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.986, year: 2016

  18. Synthesis, Crystal structure and Characterization of a New Oxalate ...

    Indian Academy of Sciences (India)

    O, N–H...O hydrogen bonds which connect ionic entities and water molecules and also by π–π stack- ing interactions between the rings of 3,5-dimethylpyrazole cations. Hence, both coordinated and uncoordinated water molecules play an important role in the hydrogen-bonding system and stabilize the structure. Keywords.

  19. Synthesis, characterization and crystal structure of new nickel ...

    Indian Academy of Sciences (India)

    ductive, luminescent, magnetic, porous, chiral or nonlinear optical materials. The most useful strategy to construct such materials is to employ appropriate bridging ..... C and 8 h were nanoparticles with size of 35–45 nm and confirmed by TEM. Further increase in thermal decomposition time led to nanosheet-like structures.

  20. Synthesis, characterization and crystal structure of new nickel ...

    Indian Academy of Sciences (India)

    Abstract. A novel nickel molybdenum complex with the 2,6-pyridine dicarboxylic acid ligand was successfully synthesized and characterized by thermogravimetric analysis and single crystal X-ray crystallography. The single-crystal X-ray data revealed that the structure is a hydrated 1-D polymer with two different Ni sites.

  1. Solid state synthesis and structural refinement of polycrystalline ...

    Indian Academy of Sciences (India)

    Unknown

    Step analysis data has been used to determine the structure of solid solution of lanthanum substituted calcium titanate. The SEM and EDAX analyses also confirm that the. CaTiO3 can act as a host for lanthanum. X-ray data has been interpreted using CRYSFIRE and POWDERCELL softwares. The h, k, l values for different ...

  2. Synthesis and structural characterization of a calcium coordination ...

    Indian Academy of Sciences (India)

    pounds showed a Ca:water ratio of 1:3 or less. A recent study based on the analysis of the crystal structures of 131 Ca-carboxylates has shown that the coordina- tion number of calcium ranges from three to ten, with octacoordination being the most favoured.5 Due to the larger ionic radius of 106 pm for Ca2+, the carboxy-.

  3. Synthesis, characterization, X-ray structure, optical properties and ...

    Indian Academy of Sciences (India)

    ESMA LAMERA

    Also, the values of dipole moment μ, the average polarizability ¯α, and the first static hyperpolarizability (β0) were computed. The theoretical and experimental results confirm the NLO behavior of both compounds. Keywords. Condensed phthalazine; DFT calculations; spectroscopic analysis; X-ray structure; NLO. 1.

  4. Synthesis, structure and thermoelectric properties of La1 ...

    Indian Academy of Sciences (India)

    2017-12-07

    Dec 7, 2017 ... All the heat treatments were limited to below 1123 K, in order to retain the. Na stoichiometry. Structural ... Nitrate–citrate gel combustion method; perovskite; monovalent ions doping; semiconductor; thermoelectric. 1. Introduction ... electricity by Terasaki et al [3] on NaCo2O4 single crystal in. 1997, there has ...

  5. Structural evolution of ZTA composites during synthesis and processing

    Czech Academy of Sciences Publication Activity Database

    Exare, C.; Kiat, J. M.; Guiblin, N.; Porcher, F.; Petříček, Václav

    2015-01-01

    Roč. 35, č. 4 (2015), s. 1273-1283 ISSN 0955-2219 R&D Projects: GA ČR(CZ) GA14-03276S Institutional support: RVO:68378271 Keywords : ceramic s * alumina–zirconia composites * structural properties * strain effect * size effect Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.933, year: 2015

  6. Synthesis and Spectroscopic, Thermal and Crystal Structure Studies ...

    African Journals Online (AJOL)

    NICO

    The salt undergoes melting followed by decomposition to give gaseous products. KEYWORDS. Hydrazine, succinic acid, hydrazinium hydrogensuccinate, crystal structure, thermal studies. 1. Introduction. Dibasic acids are known to form N2H5HA, (N2H5)2A and. N2H5HA.H2A type salts (H2A = dibasic acid) with hydrazine.

  7. Nidovirus replication structures : hijacking membranes to support viral RNA synthesis

    NARCIS (Netherlands)

    Knoops, Kèvin

    2011-01-01

    Positive-stranded RNA viruses replicate in the cytoplasm of host cells and their replication complexes are associated with modified cell membranes. We investigated the structure of the nidovirus-induced membrane modifications and found that nidoviruses transform the endoplasmic reticulum into a

  8. Synthesis, crystal structure and characterization of new biologically ...

    Indian Academy of Sciences (India)

    Sulfonamide; Cu(II) complexes; crystal structure; oxidative DNA cleavage; cytotoxic activity. 1. Introduction. The continuous demand for new ... between the base stacks of double-stranded DNA, thus showing cytotoxic effects on several ... proteins.11,12 The toxicity of Cu(II) complexes seems to be lower than classic cancer ...

  9. Synthesis, Characterization, Crystal Structure and Keto-enol Kinetics

    African Journals Online (AJOL)

    A crystal structure determination of Hbth (orthorhombic, Pbca, Z=8, R=0.0290) shows asymmetrical enolization on the side of the phenyl group. The preferred enol isomer of β-diketones containing more than one aromatic moiety that crystallizes in the solid state is determined by the resonance driving force stabilization of the ...

  10. Synthesis and structural study of platinum group metal complexes ...

    Indian Academy of Sciences (India)

    )Cl]2, [CpRu(PPh3)2Cl] and [Cp∗M(-Cl)Cl]2, respectively, in the presence of NH4PF6. They were characterized by the following techniques viz. IR, NMR, mass spectrometry and UV-visible spectroscopy. The molecular structures of [2] and [7] ...

  11. Synthesis and crystal structure of trinuclear potassium(I) complex ...

    African Journals Online (AJOL)

    A furazan-based trinuclear potassium(I) complex derived from the oxy-bridged bis(gem-dinitro)furazan (OBNF) and triaminoguanidinium (TGA) units was synthesized and characterized by elemental analyses, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The single crystal X-ray structure of the ...

  12. Potassium and magnesium succinatouranilates – Synthesis and crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, S.A., E-mail: serg.alex.novikov@gmail.com [Samara National Research University, 443086 Samara (Russian Federation); Grigoriev, M.S. [Frumkin Institute of Physical Chemistry and Electrochemistry RAS, 119071 Moscow (Russian Federation); Serezhkina, L.B.; Serezhkin, V.N. [Samara National Research University, 443086 Samara (Russian Federation)

    2017-04-15

    Single crystal X-ray diffraction has been applied to determine the structures of two new uranyl coordination polymers: K{sub 2}[(UO{sub 2}){sub 2}(C{sub 4}H{sub 4}O{sub 4}){sub 3}] (1) and [Mg(H{sub 2}O){sub 6}] [(UO{sub 2}){sub 2}(C{sub 4}H{sub 4}O{sub 4}){sub 3}]·2H{sub 2}O (2), where C{sub 4}H{sub 4}O{sub 4}{sup 2-} is succinate anion. Crystals of 1 and 2 contain polymeric complex anions [(UO{sub 2}){sub 2}(C{sub 4}H{sub 4}O{sub 4}){sub 3}]{sup 2-} with the same A{sub 2}Q{sup 02}{sub 3} crystallochemical formula (A=UO{sub 2}{sup 2+}, Q{sup 02}=C{sub 4}O{sub 4}H{sub 4}{sup 2-}), and have layered (1) or chain (2) structure. It has been found, that conformation of succinate ions is one of the factors, which affects the structure of [(UO{sub 2}){sub 2}(C{sub 4}H{sub 4}O{sub 4}){sub 3}]{sup 2-} anions. IR spectra of these new compounds are in good agreement with crystallographic data. Topological analysis of the uranium dicarboxylates with A{sub 2}Q{sup 02}{sub 3} crystallochemical formula has shown the presence of five isomers which differ from each other in coordination sequences and / or dimensionality. - Graphical abstract: Crystal structures of two new uranium(VI) coordination polymers with succinate linkers, namely K{sub 2}[(UO{sub 2}){sub 2}(C{sub 4}H{sub 4}O{sub 4}){sub 3}] (1) and [Mg(H{sub 2}O){sub 6}][(UO{sub 2}){sub 2}(C{sub 4}H{sub 4}O{sub 4}){sub 3}]·2H{sub 2}O (2), were determined by single-crystal XRD. Crystals of studied compounds are based on 2D or 1D structural units with the same composition and crystallochemical formula. Topological isomerism in A{sub 2}Q{sup 02}{sub 3} crystallochemical group and conformations of succinate anions in uranyl complexes are under discussion. - Highlights: • Two new uranium coordination polymers were synthesized. • Their structural units have the same composition and crystallochemical formula. • In spite the same composition and CCF dimensionality of units is different. • Structural features of uranyl CPs

  13. Synthesis and structure of cage-like mesoporous silica using different precursors

    International Nuclear Information System (INIS)

    Fantini, M.C.A.; Kanagussuko, C.F.; Zilioti, G.J.M.; Martins, T.S.

    2011-01-01

    Research highlights: → FDU-1 mesoporous silica was made with TEOS, Na 2 Si 3 O 7 and a new template Vorasurf 504. → The synthesis temperature of 15 deg. C improved the ordered porous structure. → HBr solution induced ordered pores, larger surface area and lattice parameter. - Abstract: In this work the synthesis of cubic, FDU-1 type, ordered mesoporous silica (OMS) was developed from two types of silicon source, tetraethyl orthosilicate (TEOS) and a less expensive compound, sodium silicate (Na 2 Si 3 O 7 ), in the presence of a new triblock copolymer template Vorasurf 504 (EO 38 BO 46 EO 38 ). For both silicon precursors the synthesis temperature was evaluated. For TEOS the effect of polymer dissolution in methanol and the acid solution (HCl and HBr) on the material structure was analyzed. For Na 2 Si 3 O 7 the influence of the polymer mass and the hydrothermal treatment time were the explored experimental parameters. The samples were examined by Small Angle X-ray Scattering (SAXS) and Nitrogen Sorption. For both precursors the decrease on the synthesis temperature from ambient, -25 deg. C, to -15 deg. C improved the ordered porous structure. For TEOS, the SAXS results showed that there is an optimum amount of hydrophobic methanol that contributed to dissolve the polymer but did not provoke structural disorder. The less electronegative Br - ions, when compared to Cl - , induced a more ordered porous structure, higher surface areas and larger lattice parameters. For Na 2 Si 3 O 7 the increase on the hydrothermal treatment time as well as the use of an optimized amount of polymer promoted a better ordered porous structure.

  14. One-pot synthesis and characterization of novel sodium tris(glycozirconate) and cerium glycolate precursors and their pyrolysis

    International Nuclear Information System (INIS)

    Ksapabutr, Bussarin; Gulari, Erdogan; Wongkasemjit, Sujitra

    2004-01-01

    A low-cost and facile route to the synthesis of bimetallic glycolato zirconate (Na 2 Zr(C 2 H 4 O 2 ) 3 ) and homometallic glycolato cerate (Ce(C 2 H 4 O 2 )), which can be used as alkoxide precursors for sodium zirconium oxide (and/or zirconia by sol-gel process) and ceria materials, has been developed from the reaction of inexpensive starting materials via the oxide one-pot synthesis (OOPS) process. Both complexes were directly synthesized from zirconium hydroxide/cerium hydroxide and ethylene glycol using base as catalyst. Sodium hydroxide was used in the synthesis of sodium tris(glycozirconate) complex while both triethylenetetramine (TETA) as catalyst and trace amount of sodium hydroxide as co-catalyst were used in the case of cerium glycolate complex. The structures of obtained products were investigated using FTIR, TGA, DSC, 1 H and 13 C NMR, elemental analyses, EDS and mass spectroscopy. Pyrolysis studies delineate the effects of temperature on the decomposition processes whereby sodium tris(glycozirconate) and cerium glycolate precursors transform into Na 2 O·ZrO 2 and CeO 2 , respectively. The resulting sodium zirconium oxide and ceria, after pyrolysis at 600 deg. C for 3 h, had BET surface areas of about 62 and 70 m 2 g -1 , respectively, and show monomodal pore size distributions in the mesopore region

  15. Synthesis, Structure, and Fluorescence of a Novel Cadmium Compound

    Science.gov (United States)

    Yao, Zhong-Liang; Chen, Wen-Tong

    2017-12-01

    A novel cadmium compound, [(CdI3)2(μ2-I)]2(Me2-4,4'-H2bipy)3 (1) (Me = methyl; 4,4'-bipy = 4,4'-bipyridine) with the Me2-4,4'-H2bipy moiety generated in situ, has been prepared through a solvothermal reaction and structurally characterized by X-ray single crystal diffraction analysis. Compound 1 is characterized by an isolated structural motif, consisting of [(CdI3)2(μ2-I)]3- anions and Me2-4,4'-H2bipy2+ cations. The [(CdI3)2(μ2-I)]3- anions and Me2-4,4'-H2bipy2+ cations interconnect together via C-H···I hydrogen-bonding interactions to complete a three-dimensional (3D) supramolecular network. Solid state fluorescent spectrum reveals an emission band in the violet region.

  16. Synthesis of -aryl--lactones and relationship: Structure ...

    Indian Academy of Sciences (India)

    The biological tests allowed to find some relationships between the structure and biological activity of the compounds studied. -Ethyl--lactones 7a–c, 8a–c and unsaturated lactones 9a–c, 10a-c were usually stronger antifeedants than their parent iodolactones 5a–c and 6a–c. trans-Iodolactones 6a–c were more active ...

  17. synthesis and crystal structure of trinuclear potassium(i)

    African Journals Online (AJOL)

    DCC = distance between ring centroids; α perpendicular distance of Cg(I) from ring J;. Cg ring O7N5C4C5N6, O16N11C8C9N12 and O1 thesis and crystal structure of trinuclear potassium(I) complex. Bull. Chem. Soc. Ethiop. 2017, 31(2) anions, and connects with five adjacent OBNF2– anions through seven n bonds ...

  18. Synthesis, characterization, x-ray structure and antimicrobial activity ...

    African Journals Online (AJOL)

    intermolecular N3—H1N1•••O1 hydrogen bonds. (Table 2), resulting in the formation of zigzag layers lying parallel to (100) (Fig. 2b). The existence of π•••π interactions involving the centroid of the N4/C9-C13 pyridine ring (π•••π distance = 3.5108(18) Å) further stabilize the molecular packing. The structure of compound 2.

  19. Synthesis, crystal structure and properties of magnesium and ...

    Indian Academy of Sciences (India)

    2015-04-01

    Apr 1, 2015 ... 2.3 X-ray crystal structure determination. Single crystal X-ray analysis of compounds 1 and 2 was done at the Sophisticated Analytical Instrument. Table 1. Crystal data and selected refinement results for (1) and (2). Empirical formula. C16H30MgO14 (1). C16H16CaO7 (2). Formula weight (g mol−1). 470.71.

  20. Synthesis and crystal structure of [chlorobis (triphenylphospino)(p ...

    Indian Academy of Sciences (India)

    The structure of complex 3 was confirmed by X-ray crystallography. It has been found to crystallize in the triclinic system with space group P-1 and unit cell parameters: a = 10.207(5) Å, b = 13.027(5) Å, c = 16.269(5) Å, = 100.054(5)°, = 99.228(5)° and = 97.234(5)°. This complex has distorted tetrahedral geometry with ...

  1. Synthesis, structural and optical properties of nanoparticles (Al, V ...

    Indian Academy of Sciences (India)

    and aluminium as co-doping element of ZnO nanopowder on structural and optoelectronic properties have been reported. 2. Experimental. 2.1 Sample preparation. Zn0.89Al0.01V0.1O nanocrystals were prepared by the sol–gel method using 16 g of zinc acetate dehydrate as precursor in a 112 ml of methanol. After 10 min ...

  2. Synthesis, structural and property studies of bismuth containing perovskites

    OpenAIRE

    Chen, Wei-tin

    2009-01-01

    Several bismuth-containing transition metal perovskites that are of interest as potential multiferroic materials have been synthesised and studied. These materials have been structurally characterised and their physical properties have been examined at varying temperatures and pressures. The new series of substituted bismuth ferrite perovskites BixCa1-xFeO3, where x = 0.4 - 1.0, has been prepared. A disordered cubic phase (x = 0.4 - 0.67) and the coexistence of rhombohedral ...

  3. Synthesis and crystal structure of [chlorobis(triphenylphospino) (p ...

    Indian Academy of Sciences (India)

    X-ray Structure of new copper(I)-thiosemicarbazone complex. 187. Table 1. Crystallographic data of complex 3. Empirical Formula. C44H38Cl2CuN3P2S. Formula Weight. 837.21. Temperature (K). 293(2). Wavelength (Å). 0.71073. Crystal system. Triclinic. Crystal size (mm). 0.3 x 0.2 x 0.2. Space group. P-1. Z, calculated. 2.

  4. Synthesis and crystal structure of a trihydrate of dinuclear ...

    African Journals Online (AJOL)

    A new compound, [Cd2(C7H6N2)3(C6H4O2N)4]·3H2O (1), has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. The two cadmium(II) ions are bridged by a carboxyl group from one 2-pyridinecarboxylate ligand. The thermal gravimetry (TG) data indicate ...

  5. The synthesis and structural characterization of novel transition metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Casteel, W.J. Jr.

    1992-09-01

    High purity KMF[sub 6] and K[sub 2]MF[sub 6] salts (M = Mo,Re, Ru, Os, Ir, Pt) are obtained from reduction hexafluorides. A rhombohedral unit cell is observed for KReF[sub 6]. Fluoride ion capture by Lewis acids from the hexafluorometallate (IV) salts affords high purity tetrafluorides for M = Mo, Re, Ru, Os, and Pd. The structure of RuF[sub 4] is determined from X-ray synchrotron and neutron powder data. Unit cells based on theorthorhombic PdF[sub 4] type cell are derived from X-ray powder data for ReF[sub 4] and OsF[sub 4]. Fluoride ion capture from KAgF[sub 4] provides the thermally unstable trifluoride as a bright, red, diamagnetic solid. The structure solution of AgF[sub 3] and redetermination of the AuF[sub 3] structure from X-ray synchrotron and neutron powder data demonstrate that the two are isostnictural. Thermal decomposition product of AgF[sub 3] is the mixed valence compound Ag[sup II]Ag[sub 2][sup III]F[sub 8]. Several new salts containing the (Ag - F)[sub n][sup n+] chain cation are prepared. The first linear (Ag - F)[sub n][sup n+] chain is observed in AgF[sup +]BF[sub 4 [sup [minus

  6. Solid state synthesis and structural characterization of zinc titanates

    Energy Technology Data Exchange (ETDEWEB)

    Ayed, Sarra, E-mail: ayedsarra1@gmail.com [Laboratory of Composite Ceramic and Polymer Materials, Scientific Faculty of Sfax (Tunisia); Abdelkefi, Helmi; Khemakhem, Hamadi [Laboratory of Ferroelectric Materials, Scientific Faculty of Sfax (Tunisia); Matoussi, Adel [Laboratory of Composite Ceramic and Polymer Materials, Scientific Faculty of Sfax (Tunisia)

    2016-08-25

    Zinc titanate composite materials were synthesized via solid state sintering process using high-purity metal oxide powders (purity ∼99.99%). The titanium incorporation into ZnO matrix was investigated by X-ray diffraction which revealed the coexistence of spinel Zn{sub 2}TiO{sub 4} and hexagonal ZnTiO{sub 3} with the ZnO wurtzite structures. No reflection peaks of rutile TiO{sub 2} phase were detected. The IR spectroscopy and Raman scattering spectroscopy were used to characterize the structural and chemical properties of the ZnO/TiO{sub 2} composites. The IR bands and vibrational modes of all crystalline phases were detected. The effect of TiO{sub 2} doping rates (x = 3, 5 and 7 wt%) on bands shifting, Raman intensity and structural quality was discussed. - Highlights: • Zinc titanates materials were synthesized via solid state sintering process. • XRD measurements reveal the formation of Zn{sub 2}TiO{sub 4}, hexagonal ZnTiO{sub 3} and ZnO phases. • IR analysis provokes the presence of Ti−O stretching vibration bands. • Raman study provokes the appearance of new zinc titanates vibrational peaks. • The TiO{sub 2} effect into ZnO is sensed by the shift and intensity changes of peaks.

  7. Uranium complexes with macrosyclic polyethers. Synthesis and structural chemical analysis

    International Nuclear Information System (INIS)

    Elbasyouny, A.

    1983-01-01

    This dissertation reports about studies on the chemical coordination behaviour of uranium of oxidation stages IV and VI with regard to twelve different macrocyclic ligands. For the preparation of the complexes, for every system a different method has been developed. The elementary analysis of the various complexes including the uranium had been done by X-ray fluorescence analysis, and the structural characterization proceeded via vibrational, uv-vis and emission spectroscopy as well as 1 H-NMR and 13 C-spin-lattice relaxation time studies. Conformational analysis of the polyethers used allowed the structural changes in the complexes to be observed. The structural analysis of the hydrous uranium VI crown ether complexes yielded information of characteristic features of these types of complexes. The first coordination sphere of the uranyl ion with covalently bonded anion remains unchanged. As to the water content, there is a certain range. Depending upon the solvent used, the complexes have two or four H 2 O molecules per formula unit. (orig./EF) [de

  8. Self-assembled SnO2 micro- and nanosphere-based gas sensor thick films from an alkoxide-derived high purity aqueous colloid precursor

    Science.gov (United States)

    Kelp, G.; Tätte, T.; Pikker, S.; Mändar, H.; Rozhin, A. G.; Rauwel, P.; Vanetsev, A. S.; Gerst, A.; Merisalu, M.; Mäeorg, U.; Natali, M.; Persson, I.; Kessler, V. G.

    2016-03-01

    Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped.Tin oxide is considered to be one of the

  9. Inhibiting NF-κB-inducing kinase (NIK): discovery, structure-based design, synthesis, structure-activity relationship, and co-crystal structures.

    Science.gov (United States)

    Li, Kexue; McGee, Lawrence R; Fisher, Ben; Sudom, Athena; Liu, Jinsong; Rubenstein, Steven M; Anwer, Mohmed K; Cushing, Timothy D; Shin, Youngsook; Ayres, Merrill; Lee, Fei; Eksterowicz, John; Faulder, Paul; Waszkowycz, Bohdan; Plotnikova, Olga; Farrelly, Ellyn; Xiao, Shou-Hua; Chen, Guoqing; Wang, Zhulun

    2013-03-01

    The discovery, structure-based design, synthesis, and optimization of NIK inhibitors are described. Our work began with an HTS hit, imidazopyridinyl pyrimidinamine 1. We utilized homology modeling and conformational analysis to optimize the indole scaffold leading to the discovery of novel and potent conformationally constrained inhibitors such as compounds 25 and 28. Compounds 25 and 31 were co-crystallized with NIK kinase domain to provide structural insights. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Synthesis, reactivity, and electronic structure of molecular uranium nitrides

    OpenAIRE

    Cleaves, Peter A.

    2016-01-01

    The study of metal-ligand multiple bonding offers insight into the electronic structure and bond of metal systems. Until recently, for uranium, such systems were limited to uranyl, and terminal chalcogenide, imide and carbene complexes. In 2012, this was extended to nitrides with the first preparation of a uranium–nitride (U≡N) species isolable under standard conditions, namely [U(TrenTIPS)(N)][Na(12C4)2] (52), which is prepared by the two-electron reduction of sodium azide with a trivalent u...

  11. Topology Synthesis of Structures Using Parameter Relaxation and Geometric Refinement

    Science.gov (United States)

    Hull, P. V.; Tinker, M. L.

    2007-01-01

    Typically, structural topology optimization problems undergo relaxation of certain design parameters to allow the existence of intermediate variable optimum topologies. Relaxation permits the use of a variety of gradient-based search techniques and has been shown to guarantee the existence of optimal solutions and eliminate mesh dependencies. This Technical Publication (TP) will demonstrate the application of relaxation to a control point discretization of the design workspace for the structural topology optimization process. The control point parameterization with subdivision has been offered as an alternative to the traditional method of discretized finite element design domain. The principle of relaxation demonstrates the increased utility of the control point parameterization. One of the significant results of the relaxation process offered in this TP is that direct manufacturability of the optimized design will be maintained without the need for designer intervention or translation. In addition, it will be shown that relaxation of certain parameters may extend the range of problems that can be addressed; e.g., in permitting limited out-of-plane motion to be included in a path generation problem.

  12. Synthesis and Crystal Structures of N-Substituted Pyrazolines

    Directory of Open Access Journals (Sweden)

    Balladka Kunhanna Sarojini

    2013-02-01

    Full Text Available Four pyrazole compounds, 3-(4-fluorophenyl-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde (1, 5-(4-bromophenyl-3-(4-fluorophenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde (2, 1-[5-(4-chlorophenyl-3-(4-fluorophenyl-4,5-dihydro-1H-pyrazol-1-yl]ethanone (3 and 1-[3-(4-fluorophenyl-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]propan-1-one (4, have been prepared by condensing chalcones with hydrazine hydrate in the presence of aliphatic acids, namely formic acid, acetic acid and propionic acid. The structures were characterized by X-ray single crystal structure determination. The dihedral angles formed between the pyrazole and the fluoro-substituted rings are 4.64(7° in 1, 5.3(4° in 2 and 4.89(6° in 3. In 4, the corresponding angles for molecules A and molecules B are 10.53(10° and 9.78(10°, respectively.

  13. Synthesis and structural characterization of actinide oxalate compounds

    International Nuclear Information System (INIS)

    Tamain, C.

    2011-01-01

    Oxalic acid is a well-known reagent to recover actinides thanks to the very low solubility of An(IV) and An(III) oxalate compounds in acidic solution. Therefore, considering mixed-oxide fuel or considering minor actinides incorporation in ceramic fuel materials for transmutation, oxalic co-conversion is convenient to synthesize mixed oxalate compounds, precursors of oxide solid solutions. As the existing oxalate single crystal syntheses are not adaptable to the actinide-oxalate chemistry or to their manipulation constrains in gloves box, several original crystal growth methods were developed. They were first validate and optimized on lanthanides and uranium before the application to transuranium elements. The advanced investigations allow to better understand the syntheses and to define optimized chemical conditions to promote crystal growth. These new crystal growth methods were then applied to a large number of mixed An1(IV)-An2(III) or An1(IV)-An2(IV) systems and lead to the formation of the first original mixed An1(IV)-An2(III) and An1(IV)-An2(IV) oxalate single crystals. Finally thanks to the first thorough structural characterizations of these compounds, single crystal X-ray diffraction, EXAFS or micro-RAMAN, the particularly weak oxalate-actinide compounds structural database is enriched, which is essential for future studied nuclear fuel cycles. (author) [fr

  14. (Biodegradable Ionomeric Polyurethanes Based on Xanthan: Synthesis, Properties, and Structure

    Directory of Open Access Journals (Sweden)

    T. V. Travinskaya

    2017-01-01

    Full Text Available New (biodegradable environmentally friendly film-forming ionomeric polyurethanes (IPU based on renewable biotechnological polysaccharide xanthan (Xa have been obtained. The influence of the component composition on the colloidal-chemical and physic-mechanical properties of IPU/Xa and based films, as well as the change of their properties under the influence of environmental factors, have been studied. The results of IR-, PMS-, DMA-, and X-ray scattering study indicate that incorporation of Xa into the polyurethane chain initiates the formation of a new polymer structure different from the structure of the pure IPU (matrix: an amorphous polymer-polymer microdomain has occurred as a result of the chemical interaction of Xa and IPU. It predetermines the degradation of the IPU/Xa films as a whole, unlike the mixed polymer systems, and plays a key role in the improvement of material performance. The results of acid, alkaline hydrolysis, and incubation into the soil indicate the increase of the intensity of degradation processes occurring in the IPU/Xa in comparison with the pure IPU. It has been shown that the introduction of Xa not only imparts the biodegradability property to polyurethane, but also improves the mechanical properties.

  15. Simulating Cellulose Structure, Properties, Thermodynamics, Synthesis, and Deconstruction with Atomistic and Coarse-Grain Models

    Energy Technology Data Exchange (ETDEWEB)

    Crowley, M. F.; Matthews, J.; Beckham, G.; Bomble, Y.; Hynninen, A. P.; Ciesielski, P. F.

    2012-01-01

    Cellulose is still a mysterious polymer in many ways: structure of microfibrils, thermodynamics of synthesis and degradation, and interactions with other plant cell wall components. Our aim is to uncover the details and mechanisms of cellulose digestion and synthesis. We report the details of the structure of cellulose 1-beta under several temperature conditions and report here the results of these studies and connections to experimental measurements and the measurement in-silico the free energy of decrystallization of several morphologies of cellulose. In spatially large modeling, we show the most recent work of mapping atomistic and coarse-grain models into tomographic images of cellulose and extreme coarse-grain modeling of interactions of large cellulase complexes with microfibrils. We discuss the difficulties of modeling cellulose and suggest future work both experimental and theoretical to increase our understanding of cellulose and our ability to use it as a raw material for fuels and materials.

  16. Some structural aspects that are relevant for synthesis of planetary gear trains

    Energy Technology Data Exchange (ETDEWEB)

    Rajasri, I. [Pathfinder Engineering College, Hanamkonda (India); Gupta, A.V.S.S.K.S. [JNTU, Hyderabad (India); Rao, Y.V.D. [BITS-Pilani. Dept. of Mechanical Engineering, Hyderabad (India)

    2012-07-01

    Gear Trains are typically used in various mechanisms including wind turbines and robots to transmit specified motion and/or torque between two or more shafts and wind turbines need drives and overdrives that amplify the speed of turbine shaft and provide high speed at generator shaft. Planetary gear trains (PGT) are compact, easy to build and operate. Therefore PGTs are most suitable for such drives including over drives. Graph theory used in synthesis of the PGTs is also useful to identify various possible structural aspects of the PGTs. Generation of PGTs is followed by the test for isomorphism in PGTs generated. In this context various structural aspects relevant for the synthesis of PGTs is described. (Author)

  17. The synthesis and structural characterization of novel transition metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Casteel, Jr., William Jack [Univ. of California, Berkeley, CA (United States)

    1992-09-01

    High purity KMF6 and K2MF6 salts (M = Mo,Re, Ru, Os, Ir, Pt) are obtained from reduction hexafluorides. A rhombohedral unit cell is observed for KReF6. Fluoride ion capture by Lewis acids from the hexafluorometallate (IV) salts affords high purity tetrafluorides for M = Mo, Re, Ru, Os, and Pd. The structure of RuF4 is determined from X-ray synchrotron and neutron powder data. Unit cells based on theorthorhombic PdF4 type cell are derived from X-ray powder data for ReF4 and OsF4. Fluoride ion capture from KAgF4 provides the thermally unstable trifluoride as a bright, red, diamagnetic solid. The structure solution of AgF3 and redetermination of the AuF3 structure from X-ray synchrotron and neutron powder data demonstrate that the two are isostnictural. Thermal decomposition product of AgF3 is the mixed valence compound AgIIAg2IIIF8. Several new salts containing the (Ag - F)$n+\\atop{n}$ chain cation are prepared. The first linear (Ag - F)$n+\\atop{n}$ chain is observed in AgF+BF4- which crystallizes in a tetragonal unit. AgFAuF4 has a triclinic unit cell and is isostructural with CuFAuF4. AgFAuF6 has an orthorhombic unit cell and appears to be isostructural with AgFAsF6. A second mixed valence silver fluoride, AgIIAgIIIF5, is prepared, which magnetic measurements indicate is probably an AgF+ salt. Magnetic data for all of the AgF+ salts exhibit low magnitude, temperature independent paramagnetism characteristic of metallic systems. Cationic AG(II) in acidic AHF solutions is a powerful oxidizer, capable of oxidizing Xe to Xe(II) and O2 to O2+. Reactions with C6F6 and C3F6 suggest an electron capture

  18. Synthesis and applications of novel silver nanoparticle structures

    Science.gov (United States)

    Dukes, Kyle

    The field of nanotechnology is rapidly expanding across disciplines as each new development is realized. New exciting technologies are being driven by advances in the application of nanotechnology; including biochemical, optical, and semiconductors research. This thesis will focus on the use of silver nanoparticles as optical labels on cells, methods of forming different small structures of silver nanoparticles, as well as the use of silver nanoparticles in the development of a photovoltaic cell. Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as optical labels for cell analysis using flow cytometry and microscopy. The excitation of plasmon resonances in nanoparticles results in strong depolarized scattering of visible light permitting detection at the single nanoparticle level. The nanoparticles were modified with neutravidin via epoxide-azide coupling chemistry and biotinylated antibodies targeting cell surface receptors were bound to the nanoparticle surface. The nanoparticle labels exhibited long-term stability under physiological conditions without aggregation or silver ion leaching. Labeled cells exhibited two orders of magnitude enhancement of the scattering intensity compared to unlabeled cells. Dimers of silver nanoparticles have been fabricated by first immobilizing a monolayer of single silver nanoparticles onto poly(4-vinylpyridine) covered glass slides. The monolayer was then exposed to adenine, which has two amines which will bind to silver. The nanoparticle monolayer, now modified with adenine, is exposed to a second suspension of nanoparticles which will bind with the amine modified monolayer. Finally, a thin silica shell is formed about the structure via solgel chemistry to prevent dissolution or aggregation upon sonication/striping. Circular arrays of silver nanoparticels are developed using a

  19. One-Dimensional SnO2 Nano structures: Synthesis and Applications

    International Nuclear Information System (INIS)

    Pan, J.; Shen, H.; Mathur, S.; Pan, J.

    2012-01-01

    Nano scale semiconducting materials such as quantum dots (0-dimensional) and one-dimensional (1D) structures, like nano wires, nano belts, and nano tubes, have gained tremendous attention within the past decade. Among the variety of 1D nano structures, tin oxide (SnO 2 ) semiconducting nano structures are particularly interesting because of their promising applications in optoelectronic and electronic devices due to both good conductivity and transparence in the visible region. This article provides a comprehensive review of the recent research activities that focus on the rational synthesis and unique applications of 1D SnO 2 nano structures and their optical and electrical properties. We begin with the rational design and synthesis of 1D SnO 2 nano structures, such as nano tubes, nano wires, nano belts, and some heterogeneous nano structures, and then highlight a range of applications (e.g., gas sensor, lithium-ion batteries, and nano photonics) associated with them. Finally, the review is concluded with some perspectives with respect to future research on 1D SnO 2 nano structures

  20. One dimensional aluminum nitride nanostructures: synthesis, structural, and luminescence properties.

    Science.gov (United States)

    Mousavi, S H; Gharavi, M A; Haratizadeh, H; Kitai, A; de Oliveira, P W

    2011-09-01

    Aluminum nitride (AIN) is a direct bandgap semiconductor with a bandgap about 6.1 eV at room temperature, the largest among semiconductors. This paper emphasizes experimental results of the growth and optical properties of AIN nanostructures by direct nitridation. The nitridation process was performed by chemical vapor deposition method with nitrogen (N2) gas flow. AIN nanostructures were analyzed by scanning electron microscope (SEM) equipped with energy-dispersive X-ray (EDX) spectroscope and photoluminescence (PL) spectroscopy. AIN nanowires with different widths from ultrathin to thick were synthesized with this method. All of the samples had high purity without presence of any other material in EDX spectrum. The PL spectra were obtained by a 325-nm helium-cadmium (He-Cd) laser as the excitation source showing high-intensity light emitting visible wavelengths for these structures at room temperature.

  1. Synthesis and Structural Characterization of ZnS Quantum Dots

    International Nuclear Information System (INIS)

    Selim, H.; Khalil, M.M.H.; Al-Kotb, M.S.; Kotkata, M.F.; Amer, H.H.

    2013-01-01

    Zinc sulfide QDs have been synthesized via a simple reaction of Zn (CH 3 COO) 2 and Na 2 S in the presence of sodium dodecyl sulphate (SDS) acting as an anionic capping material. The structure as well as characterization of the synthesized materials has been studied by XRD, EDX, SEM, TEM, TGA and FT-IR spectroscopy. Analysis of the obtained results revealed products of zinc blende ZnS nanoparticles with an average size of 5.3±0.2 nm in diameter distributed spherically and uniformly. The UV-visible absorption spectrum of the synthesized ZnS nanoparticles reflects an energy gap of 4.30 eV

  2. SYNTHESIS, CHARACTERIZATION AND CRYSTAL STRUCTURE OF BIS-(2-HYDROXYBENZALDEHYDEDIAMINOGUANIZONE

    Directory of Open Access Journals (Sweden)

    Diana Dragancea, Vladimir B. Arion, Sergiu Shova

    2008-12-01

    Full Text Available The new ligand, bis(2-hydroxybenzaldehydediaminoguanizone (1 has been synthesized and characterized by elemental analysis, IR and 1H NMR spectroscopies. The crystal structure of the compound was determined by X-ray diffraction. The ligand C15H15N5O2·C2H5OH crystallizes in the monoclinic space group P21/c with unit cell parameters a = 8.9102(3, b = 10.0357(3, c = 19.7618(6 Å, β = 98.385(2°, Z = 4, V = 1748.21(9 Å3, R1 = 0.040. The amino form of the ligand adopts a planar conformation stabilized by two intramolecular hydrogen bonds of the type O–H···N, in which the H atoms of the central amino group are directed to the lone-pair regions of the azomethine nitrogen atoms.

  3. Synthesis and structural characterization of alkali metal arsinoamides.

    Science.gov (United States)

    Chen, Xiao; Gamer, Michael T; Roesky, Peter W

    2017-12-20

    The aminoarsane Mes 2 AsN(H)Ph was prepared from Mes 2 AsCl and aniline in good yields. Deprotonation of Mes 2 AsN(H)Ph with suitable alkali metal bases resulted in the corresponding alkali metal derivatives. Thus, reaction of Mes 2 AsN(H)Ph with nBuLi, NaN(SiMe 3 ) 2 , or KH gave the metal complexes [(Mes 2 AsNPh){Li(OEt 2 ) 2 }], [(Mes 2 AsNPh){Na(OEt 2 )}] 2 , and [(Mes 2 AsNPh){K(THF)}] 2 . These are the first metal complexes ligated by an arsinoamide. All solid-state structures were established by single crystal X-ray diffraction. The lithium compounds form a monomer in the solid-state, whereas the sodium and the potassium derivatives are dimers. In the dimeric compounds intra- and intermolecular π-interaction of the aromatic rings with the metal atoms is observed.

  4. Synthesis and Crystal Structures of Two New Oxaspirocyclic Compounds

    Directory of Open Access Journals (Sweden)

    Jinhe Jiang

    2016-10-01

    Full Text Available Two new oxaspirocyclic compounds, 8-(4-(dimethylaminobenzylidene-6,10-dioxaspiro[4.5]decane-7,9-dione (1 and 8-(4-hydroxybenzylidene-6,10-dioxaspiro[4.5]decane-7,9-dione (2 have been synthesized and their structures determined by single crystal X-ray crystallography. Compound 1, C17H19NO4, belongs to the monoclinic system, space group P21/c with a = 6.2554(13 Å, b = 14.605(3 Å, c = 16.265(3 Å, β = 95.97(3°, V = 1477.9(5 Å3, Z = 4, Dc = 1.354 g/cm3, F(000 = 640, μ(MoKa = 0.097 mm−1, the final R = 0.0570 and wR = 0.1667. Compound 2, C15H14O5, is also of the monoclinic system, space group P21/c with a = 10.739(2 Å, b = 18.348(4 Å, c = 6.7799(14 Å, β = 104.20(3°, V = 1295.1(5 Å3, Z = 4, Dc = 1.407 g/cm3, F(000 = 608, μ(MoKa = 0.106 mm−1, the final R = 0.0568 and wR = 0.1739. Some C–H···O intra- and intermolecular hydrogen bonds and π··· π stacking interactions are both observed in the two lattice structures. The difference between them is that one type of C–H···π supramolecular interaction (1 and one type of O–H···O intermolecular hydrogen bond (2 are observed.

  5. Synthesis and structural evaluation of freeze-cast porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Douglas F., E-mail: souzadf@outlook.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Pimenta, Daiana S.; Vasconcelos, Daniela C.L. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nascimento, Jailton F.; Grava, Wilson [Petrobras/CENPES, Avenida Horácio Macedo 950, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ CEP:21941-915 (Brazil); Houmard, Manuel [Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 1, sala 3304 (Brazil); Vasconcelos, Wander L., E-mail: wlv@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil)

    2014-10-15

    In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.

  6. Synthesis by reverse microemulsion of nano structured ferrite to be utilized in hydrogen production by water

    International Nuclear Information System (INIS)

    Bellusci, M.; Annunziatini, C.; Alvani, C.; Colella, C.; La Barbera, A.; Padella, F.; Seralessandri, L.

    2005-10-01

    Micelle and reverse micelle microemulsions can be favourably utilized in producing nano sized particles. The paper reports a general description of microemulsions systems, as well as their application in materials synthesis. By using one of the described methods, nano structured manganese ferrite, to be utilized in hydrogen production. was synthesized and the produced material was characterized in terms of morphological, microstructure and thermal properties [it

  7. Synthesis and structure of D(3h)-symmetric triptycene trimaleimide.

    Science.gov (United States)

    Zonta, Cristiano; De Lucchi, Ottorino; Linden, Anthony; Lutz, Martin

    2010-01-07

    A new D(3h) symmetric triptycene derivative has been synthesized with the aim of obtaining molecules that are able to assemble into porous structures, and can be used in the development of new ligands. The synthesis involves a Diels-Alder reaction as the key step, followed by an oxidation and the formation of a maleimide ring. Triptycene trimaleimide furnished single crystals which have been analyzed by means of X-ray diffraction.

  8. Synthesis and Structure of D3h-Symmetric Triptycene Trimaleimide

    Directory of Open Access Journals (Sweden)

    Anthony Linden

    2010-01-01

    Full Text Available A new D3h symmetric triptycene derivative has been synthesized with the aim of obtaining molecules that are able to assemble into porous structures, and can be used in the development of new ligands. The synthesis involves a Diels-Alder reaction as the key step, followed by an oxidation and the formation of a maleimide ring. Triptycene trimaleimide furnished single crystals which have been analyzed by means of X-ray diffraction.

  9. Uranium hetero-bimetallic complexes: synthesis, structure and magnetic properties

    International Nuclear Information System (INIS)

    Le Borgne, Th.

    2000-01-01

    The aim of this thesis is to synthesize molecular complexes with uranium and transition metal ions in close proximity, to determine the nature of the magnetic interaction between them. We decided to use Schiff bases as assembling ligands, which are unusual for uranium (IV). Although the simplest Schiff bases, such as H 2 Salen, lead to ligand exchange reactions, the bi-compartmental Schiff base H 4 L 6 (bis(3-hydroxy-salicylidene) - 2,2-dimethyl-propylene) allows the crystal structure determination of the complex [L 6 Cu(pyr)]U[L 6 Cu].2pyr, obtained by reaction of the metallo-ligand H 2 L 6 Cu with U(acac) 4 . In this manner, the complexes [L 6 Co(pyr)] 2 U and [L 6 Ni(pyr)] 2 U.pyr were also isolated, as well as the compounds in which the paramagnetic ions have been exchanged by the diamagnetic ions Zn II , Zr IV and Th IV ': [L 6 Zn(pyr)] 2 U, [L 6 Cu] 2 Zr and [L 6 Cu(pyr)]Th[L 6 Cu].2pyr. These complexes are the first which involve three metallic centres assembling by the means of a hexa-dentate Schiff base. The crystalline structures show, for all these complexes, the outstanding orthogonal arrangement of the two fragments L 6 M around the central atom which is in a dodecahedral environment of eight oxygen atoms of two Schiff bases. The syntheses of the isostructural complexes Cu2 II and Zn 2 U in which the uranium (IV) ion is close, in the first one, to the paramagnetic ion Cu II and, in the second one, to the diamagnetic ion Zn II , has allowed the use of the empiric method to determine the nature of the magnetic interaction between an f element and a transition metal. The comparison of the magnetic behaviour of two complexes Cu 2 U and Zn 2 U, expressed by the variation of χT vs T, reveals the ferromagnetic interaction in the heart of the triad Cu-U-Cu. The magnetic behaviour of the complexes Cu 2 Th et Cu 2 Zr which does not show any coupling between the two copper (II) ions and the weak antiferromagnetic interaction in the Ni 2 U compound, favour the

  10. Synthesis, crystal structure and applications of palladium thiosalicylate complexes

    Directory of Open Access Journals (Sweden)

    S.B. Moosun

    2017-05-01

    Full Text Available Three palladium thiosalicylate complexes [Pd(tb(bipy]·3H2O (1, [Pd2(tb2(bipy2]·(dtdb2 (2 and [Pd2(tb2(phen2]·dtdb·H2O (3 (bipy = bipyridine; phen = phenanthroline were prepared from the reaction of PdCl2(CH3CN2 with dithiosalicylic acid (dtdb which underwent cleavage to form thiobenzoate anion (tb in DMF/MeOH. Square planar geometries of the complexes with a N2SO coordination type were proposed on the basis of single crystal X-ray structural study. The presence of trapped and uncoordinated dtdb was observed in complexes 2 and 3. Complexes 1–3 were evaluated as catalysts for Heck coupling reactions of methyl acrylate with iodobenzene, and showed moderate activities at a very low catalyst loading. Complex 1 was found to inhibit the growth of bacteria and scavenge free radicals efficiently.

  11. Structural versatility of Metal-organic frameworks: Synthesis and Characterization

    KAUST Repository

    Alsadun, Norah S.

    2017-05-01

    Metal-Organic Frameworks (MOFs), an emerging class of porous crystalline materials, have shown promising properties for diverse applications such as catalysis, gas storage and separation. The high degree of tunability of MOFs vs other solid materials enable the assembly of advanced materials with fascinating properties for specific applications. Nevertheless, the precise control in the construction of MOFs at the molecular level remains challenging. Particularly, the formation of pre-targeted multi-nuclear Molecular Building Block (MBB) precursors to unveil materials with targeted structural characteristics is captivating. The aim of my master project in the continuous quest of the group of Prof. Eddaoudi in exploring different synthetic pathways to control the assembly of Rare Earth (RE) based MOF. After giving a general overview about MOFs, I will discuss in this thesis the results of my work on the use of tri-topic oriented organic carboxylate building units with the aim to explore the assembly/construction of new porous RE based MOFs. In chapter 2 will discuss the assembly of 3-c linkers with RE metals was then evaluated based on symmetry and angularity of the three connected linkers. The focus of chapter 3 is cerium based MOFs and heterometallic system, based on 3-c ligands with different length and symmetry. Overall, the incompatibility of 3-c ligands with the 12-c cuo MBB did not allow to any formation of higher neuclearity (˃6), but it has resulted in affecting the connectivity of the cluster.

  12. Isolation, Synthesis and Structures of Cytotoxic Ginsenoside Derivatives

    Directory of Open Access Journals (Sweden)

    Yi-nan Zheng

    2007-09-01

    Full Text Available Four known ginsenosides: ginsenoside-Rb1 (1, Rb3 (2, Rd (3 and Re (4 were isolated from the methanolic extract of the traditional Chinese medicine Panax ginseng C. A. Meyer. Further enzyme reactions and chemical modifications led us to obtain ginsenoside-M1 (5 and synthesize three novel mono-esters of ginsenoside-M1, ginsenoside-DM1 (6, PM1 (7 and SM1 (8 30 - 50% of yield via a facile and green synthetic strategy. The structures were elucidated on the basis of extensive 1D- and 2DNMR, as well as high resolution ESI-TOF mass spectroscopic analyses. The isolated and synthetic compounds were tested in an anti-tumor bioassay, and compounds 5-8 showed considerable cytotoxicity (SRB against several human cancer cell lines (breast cancer MCF-7, skin melanoma SK-MEL-2 and human ovarian carcinoma B16, but moderate effects on lung carcinoma COR-L23. The other ginsenosides showed no effects.

  13. Synthesis, structural, catecholase, tyrosinase and DFT studies of pyrazoloquinoxaline derivatives

    Science.gov (United States)

    Bouanane, Zohra; Bounekhel, Mahmoud; Elkolli, Meriem; Abrigach, Farid; Khoutoul, Mohamed; Bouyala, Rabab; Touzani, Rachid; Hellal, Abdelkader

    2017-07-01

    Six functional multidentate ligands: 2,3-bis(3,5-dimethyl-1H-pyrazol-1-yl) quinoxaline, L1, 2,3-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-nitroquinoxaline, L2, 2,3-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylquinoxaline, L3, 2-(3,5-dimethyl-1H-pyrazol-1-yl)-3-hydrazinyl-6-nitroquinoxaline L4, 2-chloro-3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylquinoxaline, L5, 2-chloro-3-(3,5-dimethyl-1H-pyrazol-1-yl) quinoxaline, L6, and a new copper (II) complex, were prepared and evaluated for their catecholase activities at aerobic conditions. We found that, the reaction rate depends on: The nature of the substituents in the quinoxaline ring, counter anion, metal, concentration of ligand and the used solvent. The complex obtained in-situ from reaction of one equivalent of ligand L1 and two equivalents of Cu(CH3COO)2 in methanol showed the highest oxidation rate activity (V = 33.48 μmol L-1. min-1). In addition, geometry optimizations of the complexes in order to get better insight into the geometry and the electronic structure and chemical reactivity were carried out by means of DFT calculations.

  14. Hydrothermal Synthesis and Crystal Structure of Ionic Conductive Metal Tungstates

    Energy Technology Data Exchange (ETDEWEB)

    Shimanouchi, R F; Tsuji, T; Yagi, R; Matsumoto, Y; Nishizawa, H, E-mail: rshima@kochi-u.ac.jp [Department of Natural Science, Faculty of Science, Kochi University, 2-5-1, Akebono-cho, Kochi city, KOCHI 780 (Japan)

    2011-10-29

    Trivalent ion conducting materials with the Sc{sub 2}(WO{sub 4}){sub 3}-type crystal structure, A{sub 2}(WO{sub 4}){sub 3} (A = Sc, In, Y) and solid solutions, (Sc,In){sub 2}(WO{sub 4}){sub 3} were synthesized via an autogenous hydrothermal reaction of aqueous solutions of ScCl{sub 3}, InCl{sub 3}, Y(CH{sub 3}COO){sub 3}, and H{sub 2}WO{sub 4} in a Teflon-lined mini-autoclave for 5 h at a temperature of 523 K. Fine powder samples were pressed into discs under 50 MPa and sintered at 1273 K for 10 h. The impedance measurements of sintered materials showed the dependence of electric conductivity on the size of the conducting cation. From the precise crystallographic data obtained by Rietveld refinements of solid solutions, it was considered that the change of volume of Sc(In)O{sub 6}-octahedra and WO{sub 4}-tetrahedra.

  15. Synthesis, structural, spectroscopic and biological studies of Schiff base complexes

    Science.gov (United States)

    Diab, M. A.; El-Sonbati, A. Z.; Shoair, A. F.; Eldesoky, A. M.; El-Far, N. M.

    2017-08-01

    Schiff base ligand 4-((pyridin-2- yl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (PDMP) and its complexes were prepared and characterized on the basis of elemental analysis, IR, mass spectra and thermogravimetric analysis. All results confirm that the complexes have 1:1 (M: PMDP) stoichiometric formula [M(PMDP)Cl2H2O ] (M = Cu(II), Co(II), Ni(II) and Mn(II)), [Cd(PMDP)Cl2] and the ligand behaves as a bi/tridentate forming five-membered chelating ring towards the metal ions, bonding through azomethine nitrogen/exocyclic carbonyl oxygen, azomethine pyridine nitrogen and exocyclic carbonyl oxygen. The shift in the band positions of the groups involved in coordination has been utilized to estimate the metal-nitrogen and/or oxygen bond lengths. The complexes of Co(II), Ni(II) and Cu(II) are paramagnetic and the magnetic as well as spectral data suggest octahedral geometry, whereas the Cd(II) complex is tetrahedral. The XRD studies show that both the ligand and its metal complexes (1 and 3) show polycrystalline with crystal structure. Molecular docking was used to predict the binding between PMDP ligand and the receptors. The corrosion inhibition of mild steel in 2 M HCl solution by PDMP was explored utilizing potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and (EFM) electrochemical frequency modulation method. Potentiodynamic polarization demonstrated that PDMP compound is mixed-type inhibitor. EIS spectra exhibit one capacitive loop and confirm the protective ability. The percentage of inhibition efficiency was found to increase with increasing the inhibitor concentration.

  16. Synthesis and study of nano-structured cellulose acetate based materials for energy applications

    International Nuclear Information System (INIS)

    Fischer, F.

    2006-12-01

    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO 2 supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO 2 are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245 g.cm -3 together with a meso-porous volume of 3,40 cm 3 .g -1 was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m -1 .K -1 . In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  17. Synthesis and Single Crystal Structures of Substituted-1,3-Selenazol-2-amines

    Directory of Open Access Journals (Sweden)

    Guoxiong Hua

    2016-12-01

    Full Text Available The synthesis and X-ray single crystal structures of a series of new 4-substituted-1,3-selenazol-2-amines is reported. The efficient preparation of these compounds was carried out by two-component cyclization of the selenoureas with equimolar amounts of α-haloketones. The selenoureas were obtained from the reaction of Woollins’ reagent with cyanamides, followed by hydrolysis with water. All new compounds have been characterized by IR spectroscopy, multi-NMR (1H, 13C, 77Se spectroscopy, accurate mass measurement and single crystal X-ray structure analysis.

  18. Synthesis, structure and reactivity of rare-earth metal complexes containing anionic phosphorus ligands.

    Science.gov (United States)

    Li, Tianshu; Kaercher, Sabrina; Roesky, Peter W

    2014-01-07

    A comprehensive review of structurally characterized rare-earth metal complexes containing anionic phosphorus ligands is presented. Since rare-earth elements form hard ions and phosphorus is considered as a soft ligand, the rare-earth metal phosphorus coordination is regarded as a less favorite combination. Three classes of phosphorus ligands, (1) the monoanionic organophosphide ligands (PR2(-)) bearing one negative charge on the phosphorus atom; (2) the dianionic phosphinidene (PR(2-)) and P(3-) ligands; and (3) the pure inorganic polyphosphide ligands (Pn(x-)), are included here. Particular attention has been paid to the synthesis, structure, and reactivity of the rare-earth metal phosphides.

  19. Precursor Mediated Synthesis of Nanostructured Silicas: From Precursor-Surfactant Ion Pairs to Structured Materials

    Directory of Open Access Journals (Sweden)

    Peter Hesemann

    2014-04-01

    Full Text Available The synthesis of nanostructured anionic-surfactant-templated mesoporous silica (AMS recently appeared as a new strategy for the formation of nanostructured silica based materials. This method is based on the use of anionic surfactants together with a co-structure-directing agent (CSDA, mostly a silylated ammonium precursor. The presence of this CSDA is necessary in order to create ionic interactions between template and silica forming phases and to ensure sufficient affinity between the two phases. This synthetic strategy was for the first time applied in view of the synthesis of surface functionalized silica bearing ammonium groups and was then extended on the formation of materials functionalized with anionic carboxylate and bifunctional amine-carboxylate groups. In the field of silica hybrid materials, the “anionic templating” strategy has recently been applied for the synthesis of silica hybrid materials from cationic precursors. Starting from di- or oligosilylated imidazolium and ammonium precursors, only template directed hydrolysis-polycondensation reactions involving complementary anionic surfactants allowed accessing structured ionosilica hybrid materials. The mechanistic particularity of this approach resides in the formation of precursor-surfactant ion pairs in the hydrolysis-polycondensation mixture. This review gives a systematic overview over the various types of materials accessed from this cooperative ionic templating approach and highlights the high potential of this original strategy for the formation of nanostructured silica based materials which appears as a complementary strategy to conventional soft templating approaches.

  20. Materials-by-design: computation, synthesis, and characterization from atoms to structures

    Science.gov (United States)

    Yeo, Jingjie; Jung, Gang Seob; Martín-Martínez, Francisco J.; Ling, Shengjie; Gu, Grace X.; Qin, Zhao; Buehler, Markus J.

    2018-05-01

    In the 50 years that succeeded Richard Feynman’s exposition of the idea that there is ‘plenty of room at the bottom’ for manipulating individual atoms for the synthesis and manufacturing processing of materials, the materials-by-design paradigm is being developed gradually through synergistic integration of experimental material synthesis and characterization with predictive computational modeling and optimization. This paper reviews how this paradigm creates the possibility to develop materials according to specific, rational designs from the molecular to the macroscopic scale. We discuss promising techniques in experimental small-scale material synthesis and large-scale fabrication methods to manipulate atomistic or macroscale structures, which can be designed by computational modeling. These include recombinant protein technology to produce peptides and proteins with tailored sequences encoded by recombinant DNA, self-assembly processes induced by conformational transition of proteins, additive manufacturing for designing complex structures, and qualitative and quantitative characterization of materials at different length scales. We describe important material characterization techniques using numerous methods of spectroscopy and microscopy. We detail numerous multi-scale computational modeling techniques that complements these experimental techniques: DFT at the atomistic scale; fully atomistic and coarse-grain molecular dynamics at the molecular to mesoscale; continuum modeling at the macroscale. Additionally, we present case studies that utilize experimental and computational approaches in an integrated manner to broaden our understanding of the properties of two-dimensional materials and materials based on silk and silk-elastin-like proteins.

  1. Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

    International Nuclear Information System (INIS)

    Diallo, A.; Ngom, B.D.; Park, E.; Maaza, M.

    2015-01-01

    This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported. - Highlights: • 1st time report on synthesis of ZnO nanoparticles by a green process via Aspalathus linearis extract. • A. linearis's natural extract was used as an effective reduction/oxidizing agent. • Wurtzite nature of ZnO nanoparticles was confirmed via XRD, Raman, XPS and PL

  2. Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, A.; Ngom, B.D. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Park, E. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Nelson Mandela African Institute for Science & Technology, Arusha (Tanzania, United Republic of); Maaza, M., E-mail: Maaza@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa)

    2015-10-15

    This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported. - Highlights: • 1st time report on synthesis of ZnO nanoparticles by a green process via Aspalathus linearis extract. • A. linearis's natural extract was used as an effective reduction/oxidizing agent. • Wurtzite nature of ZnO nanoparticles was confirmed via XRD, Raman, XPS and PL.

  3. Coupling Neumann development and component mode synthesis methods for stochastic analysis of random structures

    Directory of Open Access Journals (Sweden)

    Driss Sarsri

    2014-05-01

    Full Text Available In this paper, we propose a method to calculate the first two moments (mean and variance of the structural dynamics response of a structure with uncertain variables and subjected to random excitation. For this, Newmark method is used to transform the equation of motion of the structure into a quasistatic equilibrium equation in the time domain. The Neumann development method was coupled with Monte Carlo simulations to calculate the statistical values of the random response. The use of modal synthesis methods can reduce the dimensions of the model before integration of the equation of motion. Numerical applications have been developed to highlight effectiveness of the method developed to analyze the stochastic response of large structures.

  4. Antifreeze glycopeptides: from structure and activity studies to current approaches in chemical synthesis.

    Science.gov (United States)

    Urbańczyk, Małgorzata; Góra, Jerzy; Latajka, Rafał; Sewald, Norbert

    2017-02-01

    Antifreeze glycopeptides (AFGPs) are a class of biological antifreeze agents found predominantly in Arctic and Antarctic species of fish. They possess the ability to regulate ice nucleation and ice crystal growth, thus creating viable life conditions at temperatures below the freezing point of body fluids. AFGPs usually consist of 4-55 repetitions of the tripeptide unit Ala-Ala-Thr that is O-glycosylated at the threonine side chains with β-D-galactosyl-(1 → 3)-α-N-acetyl-D-galactosamine. Due to their interesting properties and high antifreeze activity, they have many potential applications, e.g., in food industry and medicine. Current research is focused towards understanding the relationship between the structural preferences and the activity of the AFGPs, as well as developing time and cost efficient ways of synthesis of this class of molecules. Recent computational studies in conjunction with experimental results from NMR and THz spectroscopies were a possible breakthrough in understanding the mechanism of action of AFGPs. At the moment, as a result of these findings, the focus of research is shifted towards the analysis of behaviour of the hydration shell around AFGPs and the impact of water-dynamics retardation caused by AFGPs on ice crystal growth. In the field of organic synthesis of AFGP analogues, most of the novel protocols are centered around solid-phase peptide synthesis and multiple efforts are made to optimize this approach. In this review, we present the current state of knowledge regarding the structure and activity of AFGPs, as well as approaches to organic synthesis of these molecules with focus on the most recent developments.

  5. Structure-directing effects of ionic liquids in the ionothermal synthesis of metal–organic frameworks

    Directory of Open Access Journals (Sweden)

    Thomas P. Vaid

    2017-07-01

    Full Text Available Traditional synthesis of metal–organic frameworks (MOFs involves the reaction of a metal-containing precursor with an organic linker in an organic solvent at an elevated temperature, in what is termed a `solvothermal' reaction. More recently, many examples have been reported of MOF synthesis in ionic liquids (ILs, rather than an organic solvent, in `ionothermal' reactions. The high concentration of both cations and anions in an ionic liquid allows for the formation of new MOF structures in which the IL cation or anion or both are incorporated into the MOF. Most commonly, the IL cation is included in the open cavities of the MOF, countering the anionic charge of the MOF framework itself and acting as a template around which the MOF structure forms. Ionic liquids can also serve other structure-directing roles, for example, when an IL containing a single enantiomer of a chiral anion leads to a homochiral MOF, even though the IL anion is not itself incorporated into the MOF. A comprehensive review of ionothermal syntheses of MOFs, and the structure-directing effects of the ILs, is given.

  6. Template Synthesis of Noble Metal Nanocrystals with Unusual Crystal Structures and Their Catalytic Applications.

    Science.gov (United States)

    Fan, Zhanxi; Zhang, Hua

    2016-12-20

    Noble metal nanocrystals own high chemical stability, unique plasmonic and distinctive catalytic properties, making them outstanding in many applications. However, their practical applications are limited by their high cost and scarcity on the earth. One promising strategy to solve these problems is to boost their catalytic performance in order to reduce their usage amount. To realize this target, great research efforts have been devoted to the size-, composition-, shape- and/or architecture-controlled syntheses of noble metal nanocrystals during the past two decades. Impressively, recent experimental studies have revealed that the crystal structure of noble metal nanocrystals can also significantly affect their physicochemical properties, such as optical, magnetic, catalytic, mechanical, electrical and electronic properties. Therefore, besides the well-established size, composition, shape, and architecture control, the rise of crystal structure-controlled synthesis of noble metal nanocrystals will open up new opportunities to further improve their functional properties, and thus promote their potential applications in energy conversion, catalysis, biosensing, information storage, surface enhanced Raman scattering, waveguide, near-infrared photothermal therapy, controlled release, bioimaging, biomedicine, and so on. In this Account, we review the recent research progress on the crystal structure control of noble metal nanocrystals with a template synthetic approach and their crystal structure-dependent catalytic properties. We first describe the template synthetic methods, such as epitaxial growth and galvanic replacement reaction methods, in which a presynthesized noble metal nanocrystal with either new or common crystal structure is used as the template to direct the growth of unusual crystal structures of other noble metals. Significantly, the template synthetic strategy described here provides an efficient, simple and straightforward way to synthesize unusual

  7. Termocromismo em soluções de alcóxidos de Vanádio(IV: uma abordagem pela modelagem molecular Thermochromic behavior of vanadium(IV alkoxides in solution: a molecular modeling aproach

    Directory of Open Access Journals (Sweden)

    Alexandre C. de Freitas

    2010-01-01

    Full Text Available The thermochromic behavior exhibited by vanadium(IV alkoxides, [V2(μ-OPr i2(OPr i 6] and [V2(μ-ONep2(ONep6 ], OPr i = isopropoxide and ONep = neopentoxide, was studied by molecular modeling using DFT, TDDFT and INDO/S methods. The vibrational and electronic spectra calculated for [V2(μ-OPr i2(OPr i 6] were very similar to the experimental data registered for crystalline samples of the complex and for its solutions at low temperature ( 315 K were compatible with those calculated for the monomeric form, [V(OPr i4]. These results consistently point to a monomer/dimer equilibrium as an explanation for the solution thermochromism of {V(OPr i4}n. In spite of the structural similarity between [V2(μ-ONep2(ONep6 ] and [V2(μ-OPr i2(OPr i 6] in the solid state, the thermochromic behavior of the former could not be explained by the same model, and the possibility of tetranuclear aggregation at low temperatures was also investigated.

  8. Aseismic optimization of nonlinear joint elements in boiler plant structures based on substructure synthesis method

    International Nuclear Information System (INIS)

    Nishida, E.; Suzuki, K.; Yasuda, T.; Ohwa, Y.

    1993-01-01

    This paper deals with an optimum design method for joint elements in boiler plant structures which are excited by earthquakes. Characteristics of joint elements which connect the boiler and its supporting structure, are supposed to be viscoelastic, elasto-plastic, or a combination of both. Considering the expansion of this study to an active or semi-active aseismic structural control of joint elements, the structures are modeled with the aid of block diagram. In order to improve the efficiency of calculation, substructure synthesis method is introduced. Time-domain optimization is carried out using a nonlinear programming technique. To prevent seismic damage of pipes and ducts, limitations for relative displacements between the boiler and its supporting structure is introduced is inequality constraints. Elasto-plasticity and viscoelasticity of joint elements are simulated by a combination of a spring, a Coulomb friction, and a dashpot. These joint element characteristics are optimized to minimize seismic time-response of the structures. This method is applied to actual boiler plant structures and has proven to be effective and practical for aseismic designs of boiler plant structures

  9. Nickel hydroxides and related materials: a review of their structures, synthesis and properties

    Science.gov (United States)

    Hall, David S.; Lockwood, David J.; Bock, Christina; MacDougall, Barry R.

    2015-01-01

    This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH)2 and β-Ni(OH)2, are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the incorporation of ionic impurities. Several related materials are discussed, including intercalated α-derivatives and basic nickel salts. Next, a number of methods to prepare, or synthesize, nickel hydroxides are summarized, including chemical precipitation, electrochemical precipitation, sol–gel synthesis, chemical ageing, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwave-assisted synthesis, and sonochemical methods. Finally, the known physical properties of the nickel hydroxides are reviewed, including their magnetic, vibrational, optical, electrical and mechanical properties. The last section in this paper is intended to serve as a summary of both the potentially useful properties of these materials and the methods for the identification and characterization of ‘unknown’ nickel hydroxide-based samples. PMID:25663812

  10. Effect of Alcohol Structure on the Optimum Condition for Novozym 435-Catalyzed Synthesis of Adipate Esters

    Directory of Open Access Journals (Sweden)

    Mohd Basyaruddin Abdul Rahman

    2011-01-01

    Full Text Available Immobilized Candida antarctica lipase B, Novozym 435, was used as the biocatalyst in the esterification of adipic acid with four different isomers of butanol (n-butanol, sec-butanol, iso-butanol, and tert-butanol. Optimum conditions for the synthesis of adipate esters were obtained using response surface methodology approach with a four-factor-five-level central composite design concerning important reaction parameters which include time, temperature, substrate molar ratio, and amount of enzyme. Reactions under optimized conditions has yielded a high percentage of esterification (>96% for n-butanol, iso-butanol, and sec-butanol, indicating that extent of esterification is independent of the alcohol structure for primary and secondary alcohols at the optimum conditions. Minimum reaction time (135 min for achieving maximum ester yield was obtained for iso-butanol. The required time for attaining maximum yield and also the initial rates in the synthesis of di-n-butyl and di-sec-butyl adipate were nearly the same. Immobilized Candida antarctica lipase B was also capable of esterifying tert-butanol with a maximum yield of 39.1%. The enzyme is highly efficient biocatalyst for the synthesis of adipate esters by offering a simple production process and a high esterification yield.

  11. Mechanical synthesis of copper-carbon nanocomposites: Structural changes, strengthening and thermal stabilization

    International Nuclear Information System (INIS)

    Nunes, D.; Livramento, V.; Mateus, R.; Correia, J.B.; Alves, L.C.; Vilarigues, M.; Carvalho, P.A.

    2011-01-01

    Highlights: → The study characterized Cu-nanodiamond (Cu-nD) and Cu-graphite (Cu-G) composites. → Preservation of nD crystalline structure during high-energy milling was demonstrated. → Higher refinement of matrix in Cu-nD comparing to Cu-G is due to a milling mechanism. → Remarkable thermal stability and microhardness have been achieved in Cu-nD and Cu-G. → Strengthening resulted mainly from grain refinement and second-phase reinforcement. - Abstract: Processing of copper-carbon nanocomposites by mechanical synthesis poses specific challenges as carbon phases are prone to amorphization and exhibit an intrinsically difficult bonding with copper. The present work investigates Cu-nanodiamond (Cu-nD) and Cu-graphite (Cu-G) composites produced by mechanical synthesis and subsequent heat treatments. Transmission electron microscopy observations showed homogeneous particle distributions and intimate bonding between the metallic matrix and the carbon phases. Ring diffraction patterns of chemically extracted carbon phases demonstrated that milled nanodiamond preserved crystallinity, while an essentially amorphous nature could be inferred for milled graphite. Raman spectra confirmed that nanodiamond particles remained essentially unaffected by the mechanical synthesis, whereas the bands of milled graphite were significantly changed into the typical amorphous carbon fingerprint. Particle-induced X-ray emission spectroscopy showed that the total contamination originating from the milling media remained below 0.7 wt.%. The Cu-nanodiamond composite exhibited remarkable microhardness and microstructural thermal stability when compared with pure nanostructured copper.

  12. Mechanical synthesis of copper-carbon nanocomposites: Structural changes, strengthening and thermal stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, D., E-mail: daniela.nunes@ist.utl.pt [Associacao Euratom/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); LNEG, Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal); ICEMS, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Livramento, V. [Associacao Euratom/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); LNEG, Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal); Mateus, R. [Associacao Euratom/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Correia, J.B. [LNEG, Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal); Alves, L.C. [ITN, Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Vilarigues, M. [Departamento de Conservacao e Restauro e R and D Unit Vidro e da Ceramica Para as Artes, FCT-UNL, Quinta da Torre, 2829-516 Caparica (Portugal); Carvalho, P.A. [ICEMS, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Departamento de Bioengenharia, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2011-11-15

    Highlights: {yields} The study characterized Cu-nanodiamond (Cu-nD) and Cu-graphite (Cu-G) composites. {yields} Preservation of nD crystalline structure during high-energy milling was demonstrated. {yields} Higher refinement of matrix in Cu-nD comparing to Cu-G is due to a milling mechanism. {yields} Remarkable thermal stability and microhardness have been achieved in Cu-nD and Cu-G. {yields} Strengthening resulted mainly from grain refinement and second-phase reinforcement. - Abstract: Processing of copper-carbon nanocomposites by mechanical synthesis poses specific challenges as carbon phases are prone to amorphization and exhibit an intrinsically difficult bonding with copper. The present work investigates Cu-nanodiamond (Cu-nD) and Cu-graphite (Cu-G) composites produced by mechanical synthesis and subsequent heat treatments. Transmission electron microscopy observations showed homogeneous particle distributions and intimate bonding between the metallic matrix and the carbon phases. Ring diffraction patterns of chemically extracted carbon phases demonstrated that milled nanodiamond preserved crystallinity, while an essentially amorphous nature could be inferred for milled graphite. Raman spectra confirmed that nanodiamond particles remained essentially unaffected by the mechanical synthesis, whereas the bands of milled graphite were significantly changed into the typical amorphous carbon fingerprint. Particle-induced X-ray emission spectroscopy showed that the total contamination originating from the milling media remained below 0.7 wt.%. The Cu-nanodiamond composite exhibited remarkable microhardness and microstructural thermal stability when compared with pure nanostructured copper.

  13. Synthesis and Characterization of Upconversion Fluorescent Yb3+, Er3+ Doped CsY2F7 Nano- and Microcrystals

    Directory of Open Access Journals (Sweden)

    Helmut Schäfer

    2009-01-01

    Full Text Available Cs Y2F7: 78%   Y3+, 20%   Yb3+, 2%   Er3+ nanocrystals with a mean diameter of approximately 8 nm were synthesized at   185°C in the high boiling organic solvent N-(2-hydroxyethyl-ethylenediamine (HEEDA using ammonium fluoride, the rare earth chlorides and a solution of caesium alkoxide of N-(2-hydroxyethyl-ethylenediamine in HEEDA. In parallel with this approach, a microwave assisted synthesis was carried out which forms nanocrystals of the same material, about 50 nm in size, in aqueous solution at 200∘C/8 bar starting from ammonium fluoride, the rare earth chlorides, and caesium fluoride. In case of the nanocrystals, derived from the HEEDA synthesis, TEM images reveal that the particles are separated but have a broad size distribution. Also an occurred heat-treatment of these nanocrystals (600∘C for 45 minutes led to bulk material which shows highly efficient light emission upon continuous wave (CW excitation at 978 nm. Besides the optical properties, the structure and the morphology of the three products were investigated by means of powder XRD and Rietveld method.

  14. Synthesis of Zirconia Nanoparticles and Their Ameliorative Roles as Additives Concrete Structures

    Directory of Open Access Journals (Sweden)

    Masoud Negahdary

    2013-01-01

    Full Text Available We investigated synthesis of zirconia nanoparticles (Nps and their ameliorative roles as additives concrete structures. Synthesized Zirconia Nps were studied with X-ray diffraction (XRD, UV-visible spectrophotometer, and transmission electron microscope (TEM. We used standard Portland cement in related experiment Concrete Structures. The experimental or E series (E1–E4 mixtures were prepared with different amounts of ZrO2 Nps with an average particle size of 20 nm. The experimental mixtures were prepared 0.125, 0.25, 0.5 and 2.0% ZrO2 Nps/cement by weight. The modified cement with ZrO2 nanoparticles was studied with split tensile strength, flexural strength and setting time methods. Final results showed that Zirconia Nps could be used for their Ameliorative roles as Additives Concrete Structures.

  15. Synthesis, structural characterization and myorelaxant activity of 4-naphthylhexahydroquinoline derivatives containing different ester groups

    Directory of Open Access Journals (Sweden)

    Gündüz Miyase Gözde

    2016-01-01

    Full Text Available The present study reports the synthesis, structural characterization and myorelaxant activity evaluation of a series of 16 novel 4-naphthyl-hexahydroquinoline derivatives. The compounds were achieved by one-pot microwave-assisted method via a modified Hantzsch reaction. The structures of the compounds were confirmed by various spectral methods like IR, 1D-2D NMR techniques and mass analysis. X-ray studies of compound 10 provided further evidence for the proposed structure. To evaluate their myorelaxant activities, the Emax and pD2 values of the compounds and nifedipine were determined on isolated rabbit gastric fundus smooth muscle strips. The obtained results indicated that introduction of long chain alkyl groups such as 2-methoxyethyl or 2-(methacryloyloxyethyl moiety to the ester group led to the most active compounds.

  16. Metal-organic frameworks: structure, properties, methods of synthesis and characterization

    International Nuclear Information System (INIS)

    Butova, V V; Soldatov, M A; Guda, A A; Lomachenko, K A; Lamberti, C

    2016-01-01

    This review deals with key methods of synthesis and characterization of metal-organic frameworks (MOFs). The modular structure affords a wide variety of MOFs with different active metal sites and organic linkers. These compounds represent a new stage of development of porous materials in which the pore size and the active site structure can be modified within wide limits. The set of experimental methods considered in this review is sufficient for studying the short-range and long-range order of the MOF crystal structure, determining the morphology of samples and elucidating the processes that occur at the active metal site in the course of chemical reactions. The interest in metal-organic frameworks results, first of all, from their numerous possible applications, ranging from gas separation and storage to chemical reactions within the pores. The bibliography includes 362 references

  17. Facile and template-free method toward chemical synthesis of polyaniline film/nanotube structures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pei [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Zhu, Yisi [Materials Science Division, Argonne National Lab, Lemont Illinois 60439; Torres, Jorge [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Lee, Seung Hee [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-786 Korea; Yun, Minhee [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261

    2017-09-05

    A facile and template-free method is reported to synthesize a new thin film structure: polyaniline (PANI) film/nanotubes (F/N) structure. The PANI F/N is a 100-nm thick PANI film embedded with PANI nanotubes. This well-controlled method requires no surfactant or organic acid as well as relatively low concentration of reagents. Synthesis condition studies reveal that aniline oligomers with certain structures are responsible for guiding the growth of the nanotubes. Electrical characterization also indicates that the PANI F/N possesses similar field-effect transistor characteristics to bare PANI film. With its 20% increased surface-area-to-volume (S/V) ratio contributed by surface embedded nanotubes and the excellent p-type semiconducting characteristic, PANI F/N shows clear superiority compared with bare PANI film. Such advantages guarantee the PANI F/N a promising future toward the development of ultra-high sensitivity and low-cost biosensors.

  18. Solution plasma synthesis of a boron-carbon-nitrogen catalyst with a controllable bond structure.

    Science.gov (United States)

    Lee, SeungHyo; Heo, YongKang; Bratescu, Maria Antoaneta; Ueno, Tomonaga; Saito, Nagahiro

    2017-06-14

    Synthesis of boron-carbon-nitrogen (BCN) nanocarbon with a controllable bond structure for enhanced oxygen reduction reaction (ORR) activity and durability was performed using a new method of discharge in organic solution mixtures named the 'Solution Plasma Process'. Using selected precursors a new strategy for the simultaneous synthesis of nanocarbon co-doped with heteroatoms was found. The synergistic effect of N and B in an uncoupling bond state improved the formation of new active sites for the ORR performance by changing the electronic structure of the base carbon. Meanwhile, when B and N are bonded together, the BCN catalyst contributes to a reduced ORR activity by forming a balanced electronic structure in carbon. The BCN nanocarbon with an uncoupling bond state exhibits an enhanced ORR activity under alkaline conditions, with an onset potential of -0.25 V versus -0.31 V for B/N coupling and 3.43 transferred electrons during the ORR. Although the ORR activity of the B/N uncoupling nanocarbon was not as good as the typical Pt/C, the durability of this synthesized material (15.1% current decrease after 20 000 s of operation) was significantly better than that of the Pt/C catalyst (61.5% current drop under the same conditions). After the durability test, the increase of the chemical states containing oxygen was higher for Pt/C than B/N uncoupling.

  19. Structural and ferroelectrical properties of bismuth titanate ceramic powders prepared by mechanically assisted synthesis

    Directory of Open Access Journals (Sweden)

    Lazarević Z.Ž.

    2007-01-01

    Full Text Available Nanosized bismuth titanate, Bi4Ti3O12, was prepared via a high-energy ball milling process through mechanically assisted synthesis directly from the oxide mixture of Bi2O3 and TiO2. The Bi4Ti3O12 phase started to form after 1 h of milling. With increasing the milling time from 3 to 12 h, the particle size of formed Bi4Ti3O12 did not reduce significantly. The grain size was less than 16 nm and showed a strong tendency to agglomeration. The nucleation and phase formation of Bi4Ti3O12, crystal structure, microstructure, powder grain size and specific surface area were followed by XRD, Rietveld refinement analysis, SEM and the BET specific surface area measurements. Raman spectroscopy was used to explain the structural properties of Bi4Ti3O12 powder, prepared by mechanically assisted synthesis. Reduction in grain size with the increase of milling time was also noted (change in the position and relative intensity, which indicated changes in the structure, caused by nanodimension grains. The sample milled for 12 h and subsequently sintered at 1000°C for 24 h exhibited a hysteresis loop, confirming that the synthesized material possesses ferroelectric properties. .

  20. Synthesis and Structure-Activity Relationships of Novel Ecdysteroid Dioxolanes as MDR Modulators in Cancer

    Directory of Open Access Journals (Sweden)

    Ana Martins

    2013-12-01

    Full Text Available Ecdysteroids, molting hormones of insects, can exert several mild, non-hormonal bioactivities in mammals, including humans. In a previous study, we have found a significant effect of certain derivatives on the ABCB1 transporter mediated multi-drug resistance of a transfected murine leukemia cell line. In this paper, we present a structure-activity relationship study focused on the apolar dioxolane derivatives of 20-hydroxyecdysone. Semi-synthesis and bioactivity of a total of 32 ecdysteroids, including 20 new compounds, is presented, supplemented with their complete 1H- and 13C-NMR signal assignment.

  1. Aurivillius BaBi4Ti4O15 based compounds: Structure, synthesis and properties

    Directory of Open Access Journals (Sweden)

    Jelena D. Bobić

    2014-09-01

    Full Text Available The discovery of some Aurivillius materials with high Curie temperature or fatigue-free character suggests possible applications in high temperature piezoelectric devices or non-volatile ferroelectric random access memories. Furthermore, increasing concerns for environmental issues have promoted the study of new lead- free piezoelectric materials. Barium bismuth titanate (BaBi4Ti4O15 , an Aurivillius compound, is promising candidate to replace lead-based materials, both as lead-free ferroelectric and high temperature piezoelectric. In this review paper, we report a detailed overview of crystal structure, different synthesis methods and char- acteristic properties of barium bismuth titanate ferroelectric materials.

  2. Carbon Nanotubes Advanced Topics in the Synthesis, Structure, Properties and Applications

    CERN Document Server

    Jorio, Ado; Dresselhaus, Mildred S

    2008-01-01

    The carbon nanotubes field has evolved substantially since the publication of the bestseller "Carbon Nanotubes: Synthesis, Structure, Properties and Applications". The present volume builds on the generic aspects of the aforementioned book, which emphasizes the fundamentals, with the new volume emphasizing areas that have grown rapidly since the first volume, guiding future directions where research is needed and highlighting applications. The volume also includes an emphasis on areas like graphene, other carbon-like and other tube-like materials because these fields are likely to affect and influence developments in nanotubes in the next 5 years.

  3. Impact of synthesis parameters on structural and magnetic characteristics of Co-based nanoparticles

    International Nuclear Information System (INIS)

    Mourdikoudis, S.; Simeonidis, K.; Tsiaoussis, I.; Dendrinou-Samara, C.; Angelakeris, M.; Kalogirou, O.

    2009-01-01

    Two different Co-based nanostructures were produced via thermolytic decomposition or reduction of proper cobalt precursors in organic solvents under vigorous stirring. The effect of synthesis parameters on the shape, size, and composition of the particles was examined. We present the differences in the structural and magnetic properties among the as-prepared sub-micron Co 'polypod-like' particles, which display a remarkable value for saturation magnetization (182 emu/g), and the hollow CoO nanoparticles, which exhibit weak ferromagnetic features.

  4. Discrete-time variable structure system synthesis for plants with nonminimum phase zeros

    Directory of Open Access Journals (Sweden)

    Iskrenović-Momčilović Olivera I.

    2014-01-01

    Full Text Available This paper analyzes a discrete variable structure system for control n-th order plants with nonminimum phase zeros in the input-output transfer function. The problem is solved by using the technique of stable system center. The first is a discrete mathematical model of the system in the normal canonical form for a given system. Then the synthesis of state generator and discrete 'time controller using the center of a stable system. The theoretical results are demonstrated in a numerical example.

  5. Simple synthesis, structure and ab initio study of 1,4-benzodiazepine-2,5-diones

    Science.gov (United States)

    Jadidi, Khosrow; Aryan, Reza; Mehrdad, Morteza; Lügger, Thomas; Ekkehardt Hahn, F.; Ng, Seik Weng

    2004-04-01

    A simple procedure for the synthesis of pyrido[2,1-c][1,4] benzodiazepine-6,12-dione ( 1) and 1,4-benzodiazepine-2,5-diones ( 2a- 2d), using microwave irradiation and/or conventional heating is reported. The configuration of 1 was determined by single-crystal X-ray diffraction. A detailed ab initio B3LYP/6-31G* calculation of structural parameters and substituent effects on ring inversion barriers (Δ G#) and also free energy differences (Δ G0) for benzodiazepines are reported.

  6. 2-Pyridyl thiazoles as novel anti-Trypanosoma cruzi agents: structural design, synthesis and pharmacological evaluation.

    Science.gov (United States)

    Cardoso, Marcos Veríssimo de Oliveira; de Siqueira, Lucianna Rabelo Pessoa; da Silva, Elany Barbosa; Costa, Lívia Bandeira; Hernandes, Marcelo Zaldini; Rabello, Marcelo Montenegro; Ferreira, Rafaela Salgado; da Cruz, Luana Faria; Moreira, Diogo Rodrigo Magalhães; Pereira, Valéria Rêgo Alves; de Castro, Maria Carolina Accioly Brelaz; Bernhardt, Paul V; Leite, Ana Cristina Lima

    2014-10-30

    The present work reports on the synthesis, anti-Trypanosoma cruzi activities and docking studies of a novel series of 2-(pyridin-2-yl)-1,3-thiazoles derived from 2-pyridine thiosemicarbazone. The majority of these compounds are potent cruzain inhibitors and showed excellent inhibition on the trypomastigote form of the parasite, and the resulting structure-activity relationships are discussed. Together, these data present a novel series of thiazolyl hydrazones with potential effects against Chagas disease and they could be important leads in continuing development against Chagas disease. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Knowledge Based Synthesis of Efficient Structures for Concurrent Computation Using Fat-Trees and Pipelining.

    Science.gov (United States)

    1986-12-31

    based on the proof is feasible. KES.U.86.11 AFO -Th, 87-0 791 Kestrel Institute Knowledge Based Synthesis of Efficient Structures for Concurrent...its own index and those of its children . lAn unbalanced tree can be described by specifying a connection between the root of some subtrees and chosen...node T.internal-, it is assumed that t" = (concat j", k), where 7 and are the subscripts of the children . No other information can be supplied for the

  8. Synthesis, crystal structures and spectral characterization of chiral 4-R-1,2,4-triazoles

    Science.gov (United States)

    Gural'skiy, Il'ya A.; Reshetnikov, Viktor A.; Omelchenko, Irina V.; Szebesczyk, Agnieszka; Gumienna-Kontecka, Elzbieta; Fritsky, Igor O.

    2017-01-01

    1,2,4-triazoles attract attention as actively used medications and ligands for constructing coordination architectures. In this paper we describe four optically active 4-substituted 1,2,4-triazoles that have been prepared by Bayer's synthesis from the corresponding aliphatic chiral amines. This approach tends to be universal towards different triazoles and permits to conserve a homochirality of substrates. Novel asymmetric molecules have been characterized by spectroscopic techniques and their structures have been retrieved from the single crystal X-ray analysis. Chiro-optical studies of these heterocycles have been made by means of circular dichroism spectroscopy.

  9. Controllable synthesis and formation mechanism of carbon micro/nano-structural materials

    Science.gov (United States)

    Zhang, Chang'an; Lv, Meijiao; Wang, Xianbao; Li, Jing; Yang, Xuyu; Yang, Jia; Hu, Hao

    2013-10-01

    Three different structures of carbon materials, including carbon spheres, bamboo-like carbon nanotubes and straight carbon nanotubes, were obtained by pyrolysis of iron(II) phthalocyanine with different flow rates of H2 at 1000 °C. The suitable mechanism for formation process of the carbon nanomaterials from spheres to straight nanotubes was suggested. The competing processes between the catalyst forward and the shell growth have been used to explain the formation mechanism of three materials. The controllable synthesis of carbon materials was achieved only by changing the H2 flow rates, and it is important to explore applications of carbon materials with different shapes.

  10. Dependencies of photoelectric properties of SiC/Si structures grown by the method of atoms substitution on synthesis time

    Science.gov (United States)

    Grashchenko, A. S.; Kukushkin, S. A.; Osipov, A. V.; Feoktistov, N. A.

    2017-07-01

    This paper is dedicated to an exploration of the photoelectric properties of Si-SiC structures grown by the substitution method on silicon substrates of (001) orientation. For the samples with the synthesis times of 40, 60, 90, 120 and 900 s, magnitudes of the saturation currents are determined and the coefficients of efficiency are calculated. The obtained dependencies of the photoelectric characteristics on the synthesis time are explained using the theory of formation of dilatation dipoles during the synthesis by the method of atoms substitution.

  11. Preparation of Bragg mirrors on silica optical fibers and inner walls of silica capillaries by employing the sol-gel method, and titanium and silicon alkoxides

    Czech Academy of Sciences Publication Activity Database

    Bartoň, Ivo; Matějec, Vlastimil; Mrázek, Jan; Podrazký, Ondřej; Matoušek, J.

    2017-01-01

    Roč. 81, č. 3 (2017), s. 867-879 ISSN 0928-0707 R&D Projects: GA ČR GA16-10019S Grant - others:AV ČR(CZ) SAV-16-17 Program:Bilaterální spolupráce Institutional support: RVO:67985882 Keywords : Multilayered coatings * Silica and titania layersSilica and titania layers * Alkoxide sol–gel method Subject RIV: JA - Electron ics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electron ic engineering Impact factor: 1.575, year: 2016

  12. Preparation of Bragg mirrors on silica optical fibers and inner walls of silica capillaries by employing the sol-gel method, and titanium and silicon alkoxides

    Czech Academy of Sciences Publication Activity Database

    Bartoň, Ivo; Matějec, Vlastimil; Mrázek, Jan; Podrazký, Ondřej; Matoušek, J.

    2017-01-01

    Roč. 81, č. 3 (2017), s. 867-879 ISSN 0928-0707 R&D Projects: GA ČR GA16-10019S Grant - others:AV ČR(CZ) SAV-16-17 Program:Bilaterální spolupráce Institutional support: RVO:67985882 Keywords : Multilayered coatings * Silica and titania layersSilica and titania layers * Alkoxide sol–gel method Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electronic engineering Impact factor: 1.575, year: 2016

  13. Proof of the Structure of the Stemodia chilensis Tetracyclic Diterpenoid (+)-19-Acetoxystemodan-12-ol by Synthesis from (+)-Podocarpic Acid: X-ray Structure Determination of a Key Intermediate.

    Science.gov (United States)

    Leonelli, Francesca; Mostarda, Azzurra; De Angelis, Luca; Lamba, Doriano; Demitri, Nicola; La Bella, Angela; Ceccacci, Francesca; Migneco, Luisa M; Marini Bettolo, Rinaldo

    2016-04-22

    The first synthesis of (+)-19-acetoxystemodan-12-ol (1), a stemodane diterpenoid isolated from Stemodia chilensis, is described. The structure was supported by an X-ray crystallographic analysis of intermediate (+)-9a, which confirmed the proposed structure and excluded the structure of (-)-19-hydroxystemod-12-ene as a possible candidate for the Chilean Calceolaria diterpenoid to which the (-)-19-hydroxystemar-13-ene structure (9b) had been erroneously assigned.

  14. Synthesis of a mixed-valent tin nitride and considerations of its possible crystal structures.

    Science.gov (United States)

    Caskey, Christopher M; Holder, Aaron; Shulda, Sarah; Christensen, Steven T; Diercks, David; Schwartz, Craig P; Biagioni, David; Nordlund, Dennis; Kukliansky, Alon; Natan, Amir; Prendergast, David; Orvananos, Bernardo; Sun, Wenhao; Zhang, Xiuwen; Ceder, Gerbrand; Ginley, David S; Tumas, William; Perkins, John D; Stevanovic, Vladan; Pylypenko, Svitlana; Lany, Stephan; Richards, Ryan M; Zakutayev, Andriy

    2016-04-14

    Recent advances in theoretical structure prediction methods and high-throughput computational techniques are revolutionizing experimental discovery of the thermodynamically stable inorganic materials. Metastable materials represent a new frontier for these studies, since even simple binary non-ground state compounds of common elements may be awaiting discovery. However, there are significant research challenges related to non-equilibrium thin film synthesis and crystal structure predictions, such as small strained crystals in the experimental samples and energy minimization based theoretical algorithms. Here, we report on experimental synthesis and characterization, as well as theoretical first-principles calculations of a previously unreported mixed-valent binary tin nitride. Thin film experiments indicate that this novel material is N-deficient SnN with tin in the mixed ii/iv valence state and a small low-symmetry unit cell. Theoretical calculations suggest that the most likely crystal structure has the space group 2 (SG2) related to the distorted delafossite (SG166), which is nearly 0.1 eV/atom above the ground state SnN polymorph. This observation is rationalized by the structural similarity of the SnN distorted delafossite to the chemically related Sn3N4 spinel compound, which provides a fresh scientific insight into the reasons for growth of polymorphs of metastable materials. In addition to reporting on the discovery of the simple binary SnN compound, this paper illustrates a possible way of combining a wide range of advanced characterization techniques with the first-principle property calculation methods, to elucidate the most likely crystal structure of the previously unreported metastable materials.

  15. Understanding fluxes as media for directed synthesis: in situ local structure of molten potassium polysulfides.

    Science.gov (United States)

    Shoemaker, Daniel P; Chung, Duck Young; Mitchell, J F; Bray, Travis H; Soderholm, L; Chupas, Peter J; Kanatzidis, Mercouri G

    2012-06-06

    Rational exploratory synthesis of new materials requires routes to discover novel phases and systematic methods to tailor their structures and properties. Synthetic reactions in molten fluxes have proven to be an excellent route to new inorganic materials because they promote diffusion and can serve as an additional reactant, but little is known about the mechanisms of compound formation, crystal precipitation, or behavior of fluxes themselves at conditions relevant to synthesis. In this study we examine the properties of a salt flux system that has proven extremely fertile for growth of new materials: the potassium polysulfides spanning K(2)S(3) and K(2)S(5), which melt between 302 and 206 °C. We present in situ Raman spectroscopy of melts between K(2)S(3) and K(2)S(5) and find strong coupling between n in K(2)S(n) and the molten local structure, implying that the S(n)(2-) chains in the crystalline state are mirrored in the melt. In any reactive flux system, K(2)S(n) included, a signature of changing species in the melt implies that their evolution during a reaction can be characterized and eventually controlled for selective formation of compounds. We use in situ X-ray total scattering to obtain the pair distribution function of molten K(2)S(5) and model the length of S(n)(2-) chains in the melt using reverse Monte Carlo simulations. Combining in situ Raman and total scattering provides a path to understanding the behavior of reactive media and should be broadly applied for more informed, targeted synthesis of compounds in a wide variety of inorganic fluxes.

  16. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    International Nuclear Information System (INIS)

    Uekawa, N.; Endo, N.; Ishii, K.; Kojima, T.; Kakegawa, K.

    2012-01-01

    Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP) and a NH 3 aqueous solution at 368 K for 24 h. The concentration of NH 3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH 3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO 2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO 2 nanoparticles.

  17. Fischer-Tropsch synthesis on hierarchically structured cobalt nanoparticle/carbon nanofiber/carbon felt composites.

    Science.gov (United States)

    Zarubova, Sarka; Rane, Shreyas; Yang, Jia; Yu, Yingda; Zhu, Ye; Chen, De; Holmen, Anders

    2011-07-18

    The hierarchically structured carbon nanofibers (CNFs)/carbon felt composites, in which CNFs were directly grown on the surface of microfibers in carbon felt, forming a CNF layer on a micrometer range that completely covers the microfiber surfaces, were tested as a novel support material for cobalt nanoparticles in the highly exothermic Fischer-Tropsch (F-T) synthesis. A compact, fixed-bed reactor, made of disks of such composite materials, offered the advantages of improved heat and mass transfer, relatively low pressure drop, and safe handling of immobilized CNFs. An efficient 3-D thermal conductive network in the composite provided a relatively uniform temperature profile, whereas the open structure of the CNF layer afforded an almost 100 % effectiveness of Co nanoparticles in the F-T synthesis in the fixed bed. The greatly improved mass and heat transport makes the compact reactor attractive for applications in the conversion of biomass, coal, and natural gas to liquids. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Nitridomanganates of alkaline-earth metals. Synthesis, structure, and physical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikov, Alexander

    2016-12-02

    The main goal of the present work was the synthesis of alkaline-earth nitridomanganates (AE{sub x}Mn{sub y}N{sub z}) with extended anionic structures and the characterization of their electronic and magnetic properties. Up to now, only compounds with isolated nitridomanganate anions have been reported in the discussed ternary systems. A systematic exploratory synthesis, employing high-temperature treatment of AE nitrides and Mn under controlled N2 pressure, yielded more than ten new nitridomanganates. Their crystal structures contain anionic building blocks of different dimensionalities, ranging from isolated species to three-dimensional frameworks. In general, the formation of Mn-rich compositions was found to be driven by the emergence of Mn-Mn interactions, which creates a link between nitridometalates and transition-metal-rich binary nitrides. The obtained nitridomanganates display a plethora of interesting phenomena, such as large spin-orbit coupling, magnetic frustration, quenching of magnetism due to Mn-Mn interactions, and metal-insulator transition.

  19. Synthesis, biological activity and solution structure of new analogues of the antimicrobial Gramicidin S.

    Science.gov (United States)

    Kamysz, Elżbieta; Mickiewicz, Beata; Kamysz, Wojciech; Bielińska, Sylwia; Rodziewicz-Motowidło, Sylwia; Ciarkowski, Jerzy

    2011-03-01

    Gramicidin S (GS) is a cyclo-decapeptide antibiotic isolated from Bacillus brevis. The structural studies have shown that GS forms a two-stranded antiparallel β-sheet imposed by two II' β-turns. Despite its wide Gram+ and Gram- antimicrobial spectrum, GS is useless in therapy because of its high hemotoxicity in humans. It was found, however, that the analogues of GS-14 (GS with 14 amino acid residues) attained a better antimicrobial selectivity when their amphipatic moments were perturbed. In this study, we report effects of similar perturbations imposed on GS cyclo-decapeptide analogues. Having solved their structures by NMR/molecular dynamics and having tested their activities/selectivities, we have concluded that the idea of perturbation of the amphipatic moment does not work for GS-10_0 analogues. An innovative approach to the synthesis of head-to-tail cyclopeptides was used. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.

  20. Structural Synthesis of 3-DoF Spatial Fully Parallel Manipulators

    Directory of Open Access Journals (Sweden)

    Alfonso Hernandez

    2014-07-01

    Full Text Available In this paper, the architectures of three degrees of freedom (3-DoF spatial, fully parallel manipulators (PMs, whose limbs are structurally identical, are obtained systematically. To do this, the methodology followed makes use of the concepts of the displacement group theory of rigid body motion. This theory works with so-called ‘motion generators’. That is, every limb is a kinematic chain that produces a certain type of displacement in the mobile platform or end-effector. The laws of group algebra will determine the actual motion pattern of the end-effector. The structural synthesis is a combinatorial process of different kinematic chains’ topologies employed in order to get all of the 3-DoF motion pattern possibilities in the end-effector of the fully parallel manipulator.

  1. Design, synthesis, and cocrystal structure of a nonpeptide Src SH2 domain ligand.

    Science.gov (United States)

    Plummer, M S; Holland, D R; Shahripour, A; Lunney, E A; Fergus, J H; Marks, J S; McConnell, P; Mueller, W T; Sawyer, T K

    1997-11-07

    The specific association of an SH2 domain with a phosphotyrosine (pTyr)-containing sequence of another protein precipitates a cascade of intracellular molecular interactions (signals) which effect a wide range of intracellular processes. The nonreceptor tyrosine kinase Src, which has been associated with breast cancer and osteoporosis, contains an SH2 domain. Inhibition of Src SH2-phosphoprotein interactions by small molecules will aid biological proof-of-concept studies which may lead to the development of novel therapeutic agents. Structure-based design efforts have focused on reducing the size and charge of Src SH2 ligands while increasing their ability to penetrate cells and reach the intracellular Src SH2 domain target. In this report we describe the synthesis, binding affinity, and Src SH2 cocrystal structure of a small, novel, nonpeptide, urea-containing SH2 domain ligand.

  2. Isolation, structure elucidation and total synthesis of a cytotoxic dienone from Echinacea pallida.

    Science.gov (United States)

    Morandi, Stefania; Pellati, Federica; Ori, Claudia; Adinolfi, Barbara; Nieri, Paola; Benvenuti, Stefania; Prati, Fabio

    2008-12-07

    The isolation and structure characterization of a dienone from the roots of Echinacea pallida, namely (8Z,11Z)-pentadeca-8,11-dien-2-one, are described here. To assess the configuration of this secondary metabolite, the stereoselective total synthesis of the two isomeric forms, (8Z,11Z)- and (8Z,11E)-pentadeca-8,11-dien-2-one, was undertaken and the structure elucidation of the natural compound was unambiguously carried out. The cytotoxic activity of both isomers was also evaluated on a human T cell leukaemia cancer line (Jurkat cells). The results indicated that these compounds exert a dose-dependent cytotoxicity with a medium-level potency on the tested cell line.

  3. Synthesis and structural determination of twisted MoS2 nanotubes

    International Nuclear Information System (INIS)

    Santiago, P.; Schabes-Retchkiman, P.; Ascencio, J.A.; Mendoza, D.; Perez-Alvarez, M.; Espinosa, A.; Reza-SanGerman, C.; Camacho-Bragado, G.A.; Jose-Yacaman, M.

    2004-01-01

    In the present work we report the synthesis of MoS 2 nanotubes with diameters greater than 10 nm using a template method. The length and properties of these nanotubes are a direct result of the preparation method. High-resolution transmission electron microscopy is used to study the structure of these highly curved entities. Molecular dynamics simulations of MoS 2 nanotubes reveal that one of the stable forms of the nanotubes is a twisted one. The twisting of the nanotubes produces a characteristic contrast in the images, which is also studied using simulation methods. The analysis of the local contrast close to the perpendicular orientation shows geometrical arrays of dots in domain-like structures, which are demonstrated to be a product of the atomic overlapping of irregular curvatures in the nanotubes. The configuration of some of the experimentally obtained nanotubes is demonstrated to be twisted with a behavior suggesting partial plasticity. (orig.)

  4. Heteroaryl Chalcones: Design, Synthesis, X-ray Crystal Structures and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2013-10-01

    Full Text Available Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen substituted chalcones 3(a–i containing the 5-chlorothiophene moiety, their X-ray crystal structures and the evaluation of possible biological activities such as antibacterial, antifungal and reducing power abilities. The results indicate the tested compounds show a varied range of inhibition values against all the tested microbial strains. Compound 3c with a p-fluoro substituent on the phenyl ring exhibits elevated antimicrobial activity, whereas the compounds 3e and 3f displayed the least antimicrobial activities. The compounds 3d, 3e, 3f and 3i showed good ferric and cupric reducing abilities, and the compounds 3b and 3c showed the weakest reducing power in the series.

  5. Characterization of Titanium Oxide Nanoparticles Obtained by Hydrolysis Reaction of Ethylene Glycol Solution of Alkoxide

    Directory of Open Access Journals (Sweden)

    Naofumi Uekawa

    2012-01-01

    Full Text Available Transparent and stable sols of titanium oxide nanoparticles were obtained by heating a mixture of ethylene glycol solution of titanium tetraisopropoxide (TIP and a NH3 aqueous solution at 368 K for 24 h. The concentration of NH3 aqueous solution affected the structure of the obtained titanium oxide nanoparticles. For NH3 aqueous solution concentrations higher than 0.2 mol/L, a mixture of anatase TiO2 nanoparticles and layered titanic acid nanoparticles was obtained. The obtained sol was very stable without formation of aggregated precipitates and gels. Coordination of ethylene glycol to Ti4+ ions inhibited the rapid hydrolysis reaction and aggregation of the obtained nanoparticles. The obtained titanium oxide nanoparticles had a large specific surface area: larger than 350 m2/g. The obtained titanium oxide nanoparticles showed an enhanced adsorption towards the cationic dye molecules. The selective adsorption corresponded to presence of layered titanic acid on the obtained anatase TiO2 nanoparticles.

  6. Synthesis and structural characterization of coaxial nano tubes intercalated of molybdenum disulfide with carbon

    International Nuclear Information System (INIS)

    Reza San German, C.M.

    2005-01-01

    In this work the study of some fundamental aspects in the growth of unidimensional systems of coaxial nano tubes from the mold method is approached. This method is an inclusion technique of a precursor reagent into oxide nano porous alumina film (mold), and later applying some processes of synthesis it is gotten to obtain the wished material. The synthesized structures are identified later because they take place by means of the initial formation of nano tubes of MoS 2 , enclosing to carbon nano tubes by the same method, with propylene flow which generates a graphitization process that 'copy' the mold through as it flows. Binary phase MoS 2 + C nano tubes were synthesized by propylene pyrolysis inside MoS 2 nano tubes prepared by template assisted technique. The large coaxial nano tubes constituted of graphite sheets inserted between the MoS 2 layers forming the outer part, and coaxial multi wall carbon nano tubes (MWCNT) intercalated with MoS 2 inside. High resolution electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high angle annular dark field (HAADF), gatan image filter (GIF), nano beam electron diffraction patterns (NBEDP), along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nano tubes with several structural irregularities. The inter-planar spacing between MoS 2 layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of these twisted nano structures, with mechanical stretch into intercalate carbon between MoS 2 layers. Our results open up the possibility of using MoS 2 nano tubes as templates for the synthesis of new one- dimensional binary phase systems. (Author)

  7. Chemical synthesis of porous web-structured CdS thin films for photosensor applications

    International Nuclear Information System (INIS)

    Gosavi, S.R.; Nikam, C.P.; Shelke, A.R.; Patil, A.M.; Ryu, S.-W.; Bhat, J.S.; Deshpande, N.G.

    2015-01-01

    The photo-activity of chemically deposited cadmium sulphide (CdS) thin film has been studied. The simple chemical route nucleates the CdS films with size up to the mean free path of the electron. Growth Kinematics of crystalline hexagonal CdS phase in the thin film form was monitored using X-ray diffraction. The time limitation set for the formation of the amorphous/nano-crystalline material is 40 and 60 min. Thereafter enhancement of the crystalline orientation along the desired plane was identified. Web-like porous structured surface morphology of CdS thin film over the entire area is observed. With decrease in synthesis time, increase of band gap energy i.e., a blue spectral shift was seen. The activation energy of CdS thin film at low and high temperature region was examined. It is considered that this activation energy corresponds to the donor levels associated with shallow traps or surface states of CdS thin film. The photo-electrochemical performance of CdS thin films in polysulphide electrolyte showed diode-like characteristics. Exposure of light on the CdS electrode increases the photocurrent. This suggests the possibility of production of free carriers via excited ions and also the light harvesting mechanism due to porous web-structured morphology. These studies hint that the obtained CdS films can work as a photosensor. - Highlights: • Photoactivity of chemically synthesized cadmium sulphide (CdS) thin films was studied. • Web-like porous structured surface morphology of CdS thin film over the entire area was observed. • Blue spectral shift with lowering of the synthesis time suggests films can act as a window layer over the absorber layer. • Porous web-structured CdS thin films can be useful in light harvesting

  8. Synthesis, structure, optical property, and electronic structure of Ba7AgGa5Se15

    International Nuclear Information System (INIS)

    Yin, Wenlong; He, Ran; Feng, Kai; Hao, Wenyu; Yao, Jiyong; Wu, Yicheng

    2013-01-01

    Graphical abstract: -- Highlights: •A new quaternary chalcogenide Ba 7 AgGa 5 Se 15 was synthesized. •It adopts a new structure type in the space group P31c of the trigonal system. •The structure contains a three-dimensional framework built from GaSe 4 and AgSe 4 tetrahedra. •Ba 7 AgGa 5 Se 15 is a direct semiconductor with the band gap of 2.60 (2) eV. •The electronic structure was calculated to explain the optical properties. -- Abstract: A new quaternary chalcogenide Ba 7 AgGa 5 Se 15 was synthesized by solid state reaction. It crystallizes in a new structure type in the noncentrosymmetric space group P31c of the trigonal system. In the structure, three Ga2Se 4 tetrahedra and one Ga1Se 4 tetrahedron are connected to each other by corner-sharing to form [Ga 4 Se 10 ] 8− anion clusters, which are further connected to AgSe 4 tetrahedra by corner-sharing to form a three-dimensional framework with Ba, Se7, and isolated Ga3Se 4 tetrahedra residing in the cavities. The optical band gap of 2.60 (2) eV for Ba 7 AgGa 5 Se 15 was deduced from the diffuse reflectance spectrum. From a band structure calculation, Ba 7 AgGa 5 Se 15 is a direct semiconductor and the transition between Se and Ba plays an important role in the band gap

  9. Investigating the Synthesis, Structure, and Catalytic Properties of Versatile Gold-Based Nanocatalvsts

    Science.gov (United States)

    Pretzer, Lori A.

    Transition metal nanomaterials are used to catalyze many chemical reactions, including those key to environmental, medicinal, and petrochemical fields. Improving their catalytic properties and lifetime would have significant economic and environmental rewards. Potentially expedient options to make such advancements are to alter the shape, size, or composition of transition metal nanocatalysts. This work investigates the relationships between structure and catalytic properties of synthesized Au, Pd-on-Au, and Au-enzyme model transition metal nanocatalysts. Au and Pd-on-Au nanomaterials were studied due to their wide-spread application and structure-dependent electronic and geometric properties. The goal of this thesis is to contribute design procedures and synthesis methods that enable the preparation of more efficient transition metal nanocatalysts. The influence of the size and composition of Pd-on-Au nanoparticles (NPs) was systematically investigated and each was found to affect the catalyst's surface structure and catalytic properties. The catalytic hydrodechlorination of trichloroethene and reduction of 4-nitrophenol by Pd-on-Au nanoparticles were investigated as these reactions are useful for environmental and pharmaceutical synthesis applications, respectively. Structural characterization revealed that the dispersion and oxidation state of surface Pd atoms are controlled by the Au particle size and concentration of Pd. These structural changes are correlated with observed Pd-on-Au NP activities for both probe reactions, providing new insight into the structure-activity relationships of bimetallic nanocatalysts. Using the structure-dependent electronic properties of Au NPs, a new type of light-triggered biocatalyst was prepared and used to remotely control a model biochemical reaction. This biocatalyst consists of a model thermophilic glucokinase enzyme covalently attached to the surface of Au nanorods. The rod-like shape of the Au nanoparticles made the

  10. Antimicrobial profile of some novel keto esters: Synthesis, crystal structures and structure-activity relationship studies.

    Science.gov (United States)

    Khan, Imtiaz; Saeed, Aamer; Arshad, Mohammad Ifzan; White, Jonathan Michael

    2016-01-01

    Rapid increase in bacterial resistance has become a major public concern by escalating alongside a lack of development of new anti-infective drugs. Novel remedies in the battle against multidrug-resistant bacterial strains are urgently needed. So, in this context, the present work is towards the investigation of antimicrobial efficacy of some novel keto ester derivatives, which are prepared by the condensation of substituted benzoic acids with various substituted phenacyl bromides in dimethylformamide at room temperature using triethylamine as a catalyst. The structural build-up of the target compounds was accomplished by spectroscopic techniques including FTIR, (1)H and (13)C NMR spectroscopy and mass spectrometry. The purity of the synthesized compounds was ascertained by elemental analysis. The molecular structures of compounds (4b) and (4l) were established by X-ray crystallographic analysis. The prepared analogues were evaluated for their antimicrobial activity against Gram-positive (Staphylococcus aureus, Micrococcus leuteus) and Gram-negative (Pseudomonas picketti, Salmonella setuball) bacteria and two fungal pathogenic strains (Aspergillus niger, Aspergillus flavus), respectively. Among the screened derivatives, several compounds were found to possess significant activity but (4b) and (4l) turned out to be lead molecules with remarkable antimicrobial efficacy. The structure-activity relationship analysis of this study also revealed that structural modifications on the basic skeleton affected the antimicrobial activity of the synthesized compounds.

  11. Crystal Engineering: Synthesis and Structural Analysis of Coordination Polymers with Wavelike Properties

    Directory of Open Access Journals (Sweden)

    Matasebia T. Munie

    2011-10-01

    Full Text Available Supramolecular coordination polymers with wavelike structures have been synthesized by self-assembly and their structures analyzed using the sine trigonometric function. Slow evaporation of a methylene chloride-methanol solution of a 1:1 molar mixture of [M(tmhd2], where M = Co or Ni, and quinoxaline; a 1:2:1 molar mixture of [M(acac2], where M = Co or Ni, 2,2,6,6-tetramethyl-3,5-heptadione and quinoxaline; or a 1:2:1 molar mixture of [Co(acac2], dibenzoylmethane, and quinoxaline, yielded the crystalline coordination polymers. In the presence of the nitrogenous base, ligand scrambling occurs yielding the most insoluble product. The synthesis and structures of the following wavelike polymers are reported: trans-[Co(DBM2(qox]n·nH2O (2, trans-[Co(tmhd2(qox]n (3, trans-[Ni(tmhd2(qox]n (4, where DBM− = dibenzoylmethanate, tmhd− = 2,2,6,6-tetramethyl-3,5-heptadionate, and qox = quinoxaline. The wavelike structures are generated by intramolecular steric interactions and crystal packing forces between the chains. Some of the tert-butyl groups show a two-fold disorder. The sine function, φ = A sin 2πx/λ, where φ = distance (Ǻ along the polymer backbone, λ = wavelength (Ǻ, A = amplitude (Ǻ, x = distance (Ǻ along the polymer axis, provides a method to approximate and visualize the polymer structures.

  12. Molecular structure design and soft template synthesis of aza-, oxaaza- and thiaazamacrocyclic metal chelates in the gelatin matrix

    Directory of Open Access Journals (Sweden)

    Oleg V. Mikhailov

    2017-01-01

    Full Text Available The data about of soft template synthesis proceeding in gelatin matrices in [3d-element M(II ion – (N,S- or (N,O,S-ambidentate ligson – mono- or dicarbonyl ligson] systems, have been considered and discussed. The chemical nature of the final products of template synthesis formed under these specific conditions, has been compared with the chemical nature of the final products formed by template synthesis in solutions. It has been noted that in many cases, the nature and chemical composition of these products differ substantially. Specific features of the DFT calculated molecular structures of the macrocyclic compounds that can be formed due to the template synthesis in the systems indicated above, have been discussed, too. The review covers the period 1990–2015.

  13. Synthesis and Structural Characterization of ‘Non-VSEPR’ Structures of Oxo-Tungsten Complex

    OpenAIRE

    Ghammamy, Shahriare; Sahebalzamani, Hajar

    2011-01-01

    The crystal structure of [(CH3)4N]4 [WOCl4F][WO3Cl4] was determined by single crystal x-ray diffraction technique. The crystal is monoclinic, space group C 2/m, with a= 28.23(10) Å, b= 11.60(4) Å,c= 13.48(5) Å, β=118.43(7)°, V= 3886(2)Å3, Z=4. The structure was solved by direct methods and refined by least-squares methods to a final R = 0.0512 for 3825 observed reflections with I>2σ(I). In crystal there are two crystallographic distinct anions, both with cis geometry; the O-W-F and O-W-O angl...

  14. New bismuth borophosphate Bi4BPO10: Synthesis, crystal structure, optical and band structure analysis

    International Nuclear Information System (INIS)

    Babitsky, Nicolay A.; Leshok, Darya Y.; Mikhaleva, Natalia S.; Kuzubov, Aleksandr A.; Zhereb, Vladimir P.; Kirik, Sergei D.

    2015-01-01

    New bismuth borophosphate Bi 4 BPO 10 was obtained by spontaneous crystallization from the melt of correspondent composition at 804 °C. Crystal structure with orthorhombic lattice parameters: a = 22.5731(3) Å, b = 14.0523(2) Å, c = 5.5149(1) Å, V = 1749.34(4), Z = 8, SG Pcab was determined by X-ray powder diffraction technique. The [Bi 2 O 2 ] 2+ -layers, which are typical for bismuth oxide compounds, transform into cationic endless strips of 4 bismuth atoms width directed along the c-axis in Bi 4 BPO 10 . The strips combining stacks are separated by flat triangle [BO 3 ] 3− -anions within stacks. Neighboring stacks are separated by tetrahedral [PO 4 ] 3− -anions and shifted relatively to each other. Bismuth atoms are placed in 5–7 vertex oxygen irregular polyhedra. Bi 4 BPO 10 is stable up to 812 °C, then melts according to the peritectic law. The absorption spectrum in the range 350–700 nm was obtained and the width of the forbidden band was estimated as 3.46 eV. The band electronic structure of Bi 4 BPO 10 was modeled using DFT approach. The calculated band gap (3.56 eV) is in good agreement with the experimentally obtained data. - Graphical abstract: Display Omitted - Highlights: • New bismuth borophosphate with composition Bi 4 BPO 10 was synthesized. • The crystal structure was determined by X-ray powder diffraction technique. • Bismuth-oxygen part [Bi 4 O 3 ] 6+ forms endless strips of 4 bismuth atoms width. • Electronic structure was modeled by DFT method. • The calculated band gap (3.56 eV) is very close to the experimental one (3.46 eV)

  15. Synthesis and Structural Characterization of ‘Non-VSEPR’ Structures of Oxo-Tungsten Complex

    Directory of Open Access Journals (Sweden)

    Shahriare Ghammamy

    2011-01-01

    Full Text Available The crystal structure of [(CH34N]4 [WOCl4F][WO3Cl4] was determined by single crystal x-ray diffraction technique. The crystal is monoclinic, space group C 2/m, with a= 28.23(10 Å, b= 11.60(4 Å,c= 13.48(5 Å, β=118.43(7°, V= 3886(2Å3, Z=4. The structure was solved by direct methods and refined by least-squares methods to a final R = 0.0512 for 3825 observed reflections with I>2σ(I. In crystal there are two crystallographic distinct anions, both with cis geometry; the O-W-F and O-W-O angles are 97.5(3° and 103.1(3 ° respectively. All structures are cis configurations that confirm a preference for angles below 90° and 180° between cis and trans σ-donor ligands, respectively.

  16. Copper coordination polymers constructed from thiazole-5-carboxylic acid: Synthesis, crystal structures, and structural transformation

    Energy Technology Data Exchange (ETDEWEB)

    Meundaeng, Natthaya; Rujiwatra, Apinpus [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prior, Timothy J., E-mail: t.prior@hull.ac.uk [Chemistry, University of Hull, Kingston upon Hull HU6 7RX (United Kingdom)

    2017-01-15

    We have successfully prepared crystals of thiazole-5-carboxylic acid (5-Htza) (L) and three new thiazole-5-carboxylate-based Cu{sup 2+} coordination polymers with different dimensionality, namely, 1D [Cu{sub 2}(5-tza){sub 2}(1,10-phenanthroline){sub 2}(NO{sub 3}){sub 2}] (1), 2D [Cu(5-tza){sub 2}(MeOH){sub 2}] (2), and 3D [Cu(5-tza){sub 2}]·H{sub 2}O (3). These have been characterized by single crystal X-ray diffraction and thermogravimetry. Interestingly, the 2D network structure of 2 can directly transform into the 3D framework of 3 upon removal of methanol molecules at room temperature. 2 can also undergo structural transformation to produce the same 2D network present in the known [Cu(5-tza){sub 2}]·1.5H{sub 2}O upon heat treatment for 2 h. This 2D network can adsorb water and convert to 3 upon exposure to air. - Highlights: • Rare examples of coordination polymers of thiazole-5-carboxylic acid were prepared. • Non-covalent interactions play a key role on the assembly of the complexes in solid state. • Structural transformation of a 2D framework to a 3D upon removal of methanol is observed.

  17. Synthesis and Crystal Structure of a New Hydrated Benzimidazolium Salt Containing Spiro Structure

    Directory of Open Access Journals (Sweden)

    Wulan Zeng

    2017-10-01

    Full Text Available A new hydrated benzimidazolium salt containing spiro structure was obtained when benzimidazole is added to ethyl alcohol of 1,5-dioxaspiro[5.5]undecane-2,4-dione and trimethoxymethane. The title compound (C19H21O8 (C7H7N2 (0.5H2O was characterized by elemental analysis, IR, UV-Vis, and single-crystal X-ray diffraction. The result shows that it belongs to the triclinic system, space group P-1, with a = 11.017(2 Å, b = 11.424(2 Å, c = 11.650(2 Å, α = 70.60(3°, β = 71.00(3°, γ = 67.64(3°, Mr = 505.51, V = 1245.2(5 Å, Z = 2, Dc = 1.348 g/cm3, F(000 = 534, μ(MoKa = 0.102 mm−1. There exist two types of hydrogen bonds in the crystal. (C19H21O8− anions and (C7H7N2+ cations are linked by N–H···O hydrogen bonds, while (C19H21O8− anions and free water are linked by O–H···O hydrogen bonds. All of the above hydrogen bonds form a one-dimensional (1D-chained structure. The 1D chains further links the molecule into a three-dimensional (3D-layered structure.

  18. Synthesis of some pyridine and pyrimidine derivatives via Michael-Addition

    International Nuclear Information System (INIS)

    El-Baih, Fatma E.M.; Al-Rasheed, Hessa H.; Al-Hazimi, Hassan M.

    2006-01-01

    Synthesis of pyridine and pyrimidine analogues 4 and 6-9 were achieved by Michael-addition of compounds containing either active methylene groups like, malononitrile , ethyl cyanoacetate and 1-tetralone or compounds containing active hydrogen atoms like, guanidine in the presence of an oxidizing agent and thiourea to 2-arylmethylidine-1-tetralone and 2-arylmethylidine-6-methoxy-1-tetralone (2) (enones). Addition of malononitrile in piperidine at room temperature to 2-amino-3-cyno-naphtho [1, 2-malonoitrile in sodium alkoxide or sodium hydroxide to 2 gave 4. Cyclization of 3a with acetic anhydride in the presence of conc. H2sO4 gave the naphtha-pyrano[2, 3-d]pyrimidin-8-one (5). Condensation of the pyrimidine thione derivatives 9 with chloroacetic acid gave the 3-oxobenzo[h]thiazoladino[2, 3-b]quinazoline derivatives (10), which were reacted through their active methylene groups with aromatic aldehydes to give the arylidine derivatives 11. These compounds were also prepared in one step by reacting 9 with chloroacetic acid and aromatic aldehydes. Condensation of 9 with 3-bromopropanoic acid gave 4-oxo-benzo[h]1, 3-thiazino[2, 3-b]quinazoline derivatives (12). The structures of the prepared compounds were mainly confirmed on the basis of spectroscopic methods. (author)

  19. Solventless synthesis, morphology, structure and magnetic properties of iron oxide nanoparticles

    Science.gov (United States)

    Das, Bratati; Kusz, Joachim; Reddy, V. Raghavendra; Zubko, Maciej; Bhattacharjee, Ashis

    2017-12-01

    In this study we report the solventless synthesis of iron oxide through thermal decomposition of acetyl ferrocene as well as its mixtures with maliec anhydride and characterization of the synthesized product by various comprehensive physical techniques. Morphology, size and structure of the reaction products were investigated by scanning electron microscopy, transmission electron microscopy and X-ray powder diffraction technique, respectively. Physical characterization techniques like FT-IR spectroscopy, dc magnetization study as well as 57Fe Mössbauer spectroscopy were employed to characterize the magnetic property of the product. The results observed from these studies unequivocally established that the synthesized materials are hematite. Thermal decomposition has been studied with the help of thermogravimetry. Reaction pathway for synthesis of hematite has been proposed. It is noted that maliec anhydride in the solid reaction environment as well as the gaseous reaction atmosphere strongly affect the reaction yield as well as the particle size. In general, a method of preparing hematite nanoparticles through solventless thermal decomposition technique using organometallic compounds and the possible use of reaction promoter have been discussed in detail.

  20. InSe monolayer: synthesis, structure and ultra-high second-harmonic generation

    Science.gov (United States)

    Zhou, Jiadong; Shi, Jia; Zeng, Qingsheng; Chen, Yu; Niu, Lin; Liu, Fucai; Yu, Ting; Suenaga, Kazu; Liu, Xinfeng; Lin, Junhao; Liu, Zheng

    2018-04-01

    III–IV layered materials such as indium selenide have excellent photoelectronic properties. However, synthesis of materials in such group, especially with a controlled thickness down to monolayer, still remains challenging. Herein, we demonstrate the successful synthesis of monolayer InSe by physical vapor deposition (PVD) method. The high quality of the sample was confirmed by complementary characterization techniques such as Raman spectroscopy, atomic force microscopy (AFM) and high resolution annular dark field scanning transmission electron microscopy (ADF-STEM). We found the co-existence of different stacking sequence (β- and γ-InSe) in the same flake with a sharp grain boundary in few-layered InSe. Edge reconstruction is also observed in monolayer InSe, which has a distinct atomic structure from the bulk lattice. Moreover, we discovered that the second-harmonic generation (SHG) signal from monolayer InSe shows large optical second-order susceptibility that is 1–2 orders of magnitude higher than MoS2, and even 3 times of the largest value reported in monolayer GaSe. These results make atom-thin InSe a promising candidate for optoelectronic and photosensitive device applications.

  1. Topotactic synthesis of strontium cobalt oxyhydride thin film with perovskite structure

    Science.gov (United States)

    Katayama, Tsukasa; Chikamatsu, Akira; Kamisaka, Hideyuki; Yokoyama, Yuichi; Hirata, Yasuyuki; Wadati, Hiroki; Fukumura, Tomoteru; Hasegawa, Tetsuya

    2015-10-01

    The substitution of hydride anions (H-) into transition metal oxides has recently become possible through topotactic reactions or high-pressure synthesis methods. However, the fabrication of oxyhydrides is still difficult because of their inherently less-stable frameworks. In this study, we successfully fabricated perovskite SrCoOxHy thin films via the topotactic hydride doping of brownmillerite SrCoO2.5 epitaxial thin films with CaH2. The perovskite-type cation framework was maintained during the topotactic treatment owing to epitaxial stabilization. Structural and chemical analyses accompanied by X-ray absorption spectroscopy measurements revealed that the doped hydride ions form a two-dimensional network of Co-H--Co bonds, in contrast to other reported perovskite oxyhydrides, SrMO3-xHx (M = Cr, Ti, V). The SrCoOxHy thin film exhibited insulating behavior and had a direct band gap of 2.1 eV. Thus, topotactic hydride doping of transition-metal-oxide thin films on suitable substrates is a promising method for the synthesis of new transition metal oxyhydrides.

  2. Topotactic synthesis of strontium cobalt oxyhydride thin film with perovskite structure

    Directory of Open Access Journals (Sweden)

    Tsukasa Katayama

    2015-10-01

    Full Text Available The substitution of hydride anions (H− into transition metal oxides has recently become possible through topotactic reactions or high-pressure synthesis methods. However, the fabrication of oxyhydrides is still difficult because of their inherently less-stable frameworks. In this study, we successfully fabricated perovskite SrCoOxHy thin films via the topotactic hydride doping of brownmillerite SrCoO2.5 epitaxial thin films with CaH2. The perovskite-type cation framework was maintained during the topotactic treatment owing to epitaxial stabilization. Structural and chemical analyses accompanied by X-ray absorption spectroscopy measurements revealed that the doped hydride ions form a two-dimensional network of Co-H−-Co bonds, in contrast to other reported perovskite oxyhydrides, SrMO3−xHx (M = Cr, Ti, V. The SrCoOxHy thin film exhibited insulating behavior and had a direct band gap of 2.1 eV. Thus, topotactic hydride doping of transition-metal-oxide thin films on suitable substrates is a promising method for the synthesis of new transition metal oxyhydrides.

  3. Topotactic synthesis of strontium cobalt oxyhydride thin film with perovskite structure

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Tsukasa [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp; Kamisaka, Hideyuki [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Yokoyama, Yuichi; Hirata, Yasuyuki; Wadati, Hiroki [Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581 (Japan); Fukumura, Tomoteru [CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Department of Chemistry, Tohoku University, Miyagi 980-8578 (Japan); Hasegawa, Tetsuya [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); CREST, Japan Science and Technology Agency (JST), Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), Kawasaki 213-0012 (Japan)

    2015-10-15

    The substitution of hydride anions (H{sup −}) into transition metal oxides has recently become possible through topotactic reactions or high-pressure synthesis methods. However, the fabrication of oxyhydrides is still difficult because of their inherently less-stable frameworks. In this study, we successfully fabricated perovskite SrCoO{sub x}H{sub y} thin films via the topotactic hydride doping of brownmillerite SrCoO{sub 2.5} epitaxial thin films with CaH{sub 2}. The perovskite-type cation framework was maintained during the topotactic treatment owing to epitaxial stabilization. Structural and chemical analyses accompanied by X-ray absorption spectroscopy measurements revealed that the doped hydride ions form a two-dimensional network of Co-H{sup −}-Co bonds, in contrast to other reported perovskite oxyhydrides, SrMO{sub 3−x}H{sub x} (M = Cr, Ti, V). The SrCoO{sub x}H{sub y} thin film exhibited insulating behavior and had a direct band gap of 2.1 eV. Thus, topotactic hydride doping of transition-metal-oxide thin films on suitable substrates is a promising method for the synthesis of new transition metal oxyhydrides.

  4. Electrospray synthesis and properties of hierarchically structured PLGA TIPS microspheres for use as controlled release technologies.

    Science.gov (United States)

    Malik, Salman A; Ng, Wing H; Bowen, James; Tang, Justin; Gomez, Alessandro; Kenyon, Anthony J; Day, Richard M

    2016-04-01

    Microsphere-based controlled release technologies have been utilized for the long-term delivery of proteins, peptides and antibiotics, although their synthesis poses substantial challenges owing to formulation complexities, lack of scalability, and cost. To address these shortcomings, we used the electrospray process as a reproducible, synthesis technique to manufacture highly porous (>94%) microspheres while maintaining control over particle structure and size. Here we report a successful formulation recipe used to generate spherical poly(lactic-co-glycolic) acid (PLGA) microspheres using the electrospray (ES) coupled with a novel thermally induced phase separation (TIPS) process with a tailored Liquid Nitrogen (LN2) collection scheme. We show how size, shape and porosity of resulting microspheres can be controlled by judiciously varying electrospray processing parameters and we demonstrate examples in which the particle size (and porosity) affect release kinetics. The effect of electrospray treatment on the particles and their physicochemical properties are characterized by scanning electron microscopy, confocal Raman microscopy, thermogravimetric analysis and mercury intrusion porosimetry. The microspheres manufactured here have successfully demonstrated long-term delivery (i.e. 1week) of an active agent, enabling sustained release of a dye with minimal physical degradation and have verified the potential of scalable electrospray technologies for an innovative TIPS-based microsphere production protocol. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Structural Studies of Silver Nanoparticles Obtained Through Single-Step Green Synthesis

    International Nuclear Information System (INIS)

    Peddi, Siva Prasad; Sadeh, Bilal Abdallah

    2015-01-01

    Green synthesis of silver Nanoparticles (AGNP's) has been the most prominent among the metallic nanoparticles for research for over a decade and half now due to both the simplicity of preparation and the applicability of biological species with extensive applications in medicine and biotechnology to reduce and trap the particles. The current article uses Eclipta Prostrata leaf extract as the biological species to cap the AGNP's through a single step process. The characterization data obtained was used for the analysis of the sample structure. The article emphasizes the disquisition of their shape and size of the lattice parameters and proposes a general scheme and a mathematical model for the analysis of their dependence. The data of the synthesized AGNP's has been used to advantage through the introduction of a structural shape factor for the crystalline nanoparticles. The properties of the structure of the AGNP's proposed and evaluated through a theoretical model was undeviating with the experimental consequences. This modus operandi gives scope for the structural studies of ultrafine particles prepared using biological methods. (paper)

  6. An Investigation of Porous Structure of TiNi-Based SHS-Materials Produced at Different Initial Synthesis Temperatures

    Science.gov (United States)

    Khodorenko, V. N.; Anikeev, S. G.; Kokorev, O. V.; Yasenchuk, Yu. F.; Gunther, V. É.

    2018-02-01

    An investigation of structural characteristics and behavior of TiNi-based pore-permeable materials manufactured by the methods of selfpropagating high-temperature synthesis (SHS) at the initial synthesis temperatures T = 400 and 600°C is performed. It is shown that depending on the temperature regime, the resulting structure and properties of the material can differ. It is found out that the SHS-material produced at the initial synthesis temperature T = 400°C possesses the largest number of micropores in the pore wall surface structure due to a high phase inhomogeneity of the alloy. The regime of structure optimization of the resulting materials is described and the main stages of formation of the pore wall microporous surfaces are revealed. It is demonstrated that after optimization of the surface structure of a TiNi-based fine-pore alloy by its chemical etching, the fraction of micropores measuring in size less than 50 nm increased from 59 to 68%, while the number of pores larger than 1 μm increased twofold from 11 to 22%. In addition, peculiar features of interaction between certain cell cultures with the surface of the SHS-material manufactured at different initial synthesis temperatures are revealed. It is found out that the dynamics of the cell material integration depends on the pore wall surface morphology and dimensions of macropores.

  7. Synthesis and Structural Characterization of Carboxylate-Based Metal-Organic Frameworks and Coordination Networks

    Science.gov (United States)

    Calderone, Paul

    Coordination networks (CNs) and metal-organic frameworks (MOFs) are crystalline materials composed of metal ions linked by multifunctional organic ligands. From these connections, infinite arrays of one-, two-, or three-dimensional networks can be formed. Exploratory synthesis and research of novel CNs and MOFs is of current interest because of their many possible industrial applications including gas storage, catalysis, magnetism, and luminescence. A variety of metal centers and organic ligands can be used to synthesize MOFs and CNs under a range of reaction conditions, leading to extraordinary structural diversity. The characteristics of the metals and linkers, such as properties and coordination preferences, play the biggest role in determining the structure and properties of the resulting network. Thus, the choice of metal and linker is dictated by the desired traits of the target network. The pervasive use of transition metal centers in MOF synthesis stems from their well-known coordination behavior with carboxylate-based linkers, thus facilitating design strategies. Conversely, CNs and MOFs based on s-block and lanthanide metals are less studied because each group presents unique challenges to structure prediction. Lanthanide metals have variable coordination spheres capable of accommodating up to twelve atoms, while the bonding in s-block metals takes on a mainly ionic character. In spite of these obstacles, lanthanide and s-block CNs are worthwhile synthetic targets because of their unique properties. Interesting photoluminescent and sensing materials can be developed using lanthanide metals, whereas low atomic weight s-block metals may afford an advantage in gravimetric advantages for gas storage applications. The aim of this research was to expand the current understanding of carboxylate-based CN and MOF synthesis by varying the metals, solvents, and temperatures used. To this end, magnesium-based CNs were examined using a variety of aromatic carboxylate

  8. Nanoparticle synthesis of zinc peroxide: structural and morphological characterization for bactericidal applications

    International Nuclear Information System (INIS)

    Colonia, Roberto; Martinez, Vanessa C.; Solis, Jose L.; Gomez, Monica M.

    2013-01-01

    Zinc peroxide (ZnO 2 ) nanoparticles were synthesized by sol-gel technique. The chemicals used for the synthesis were zinc acetate di-hydrate (Zn(CH 3 COO) 2. 2H 2 O) and hydrogen peroxide (H 2 O 2 ) at 30 % in an aqueous solution with sonication. The structure of the ZnO 2 nanoparticles was characterized by X-ray diffraction. While the morphology and the cluster size were determined using scanning and transmission electron microscopy. For a preliminary evaluation of the bactericidal properties of the ZnO 2 , the material was exposed to Staphylococcus aureus, Escherichia coli y Bacillus subtili, and the nanoparticles presented good bactericidal properties. (author)

  9. Synthesis, growth, structure determination and optical properties of chalcone derivative single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Karthi, S., E-mail: girijaeaswaradas@gmail.com; Girija, E. K., E-mail: girijaeaswaradas@gmail.com [Department of Physics, Periyar University, Salem - 636011 (India)

    2014-04-24

    Acquiring large nonlinear optical (NLO) efficient organic material is essential for the development of optoelectronics and photonic devices. Chalcone is the donor - Π - acceptor - Π - donor (D-Π-A-Π-D) type conjugated molecule with appreciable hyperpolarizability of potential interest in NLO applications. The addition of vinyl and electron donor groups in the chalcone molecule may enhance the second harmonic generation (SHG) efficiency. Here we report the synthesis, crystal growth and characterization of a chalcone derivative 1-(4-methylphenyl)-5-(4-methoxyphenyl)-penta-2,4-dien-1-one (MPMPP). The MPMPP crystal was grown by slow evaporation solution growth technique from acetone. The grown crystal structure was studied by single crystal X-ray diffraction. The SHG efficiency of the grown crystal was determined by Kurtz and Perry method.

  10. Fused 1,2,3-Dithiazoles: Convenient Synthesis, Structural Characterization, and Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Lidia S. Konstantinova

    2016-05-01

    Full Text Available A new general protocol for synthesis of fused 1,2,3-dithiazoles by the reaction of cyclic oximes with S2Cl2 and pyridine in acetonitrile has been developed. The target 1,2,3-dithiazoles fused with various carbocycles, such as indene, naphthalenone, cyclohexadienone, cyclopentadiene, and benzoannulene, were selectively obtained in low to high yields. In most cases, the hetero ring-closure was accompanied by chlorination of the carbocyclic moieties. With naphthalenone derivatives, a novel dithiazole rearrangement (15→13 featuring unexpected movement of the dithiazole ring from α- to β-position, with respect to keto group, was discovered. Molecular structure of 4-chloro-5H-naphtho[1,2-d][1,2,3]dithiazol-5-one 13 was confirmed by single-crystal X-ray diffraction. Electrochemical properties of 13 were studied by cyclic voltammetry and a complex behavior was observed, most likely including hydrodechlorination at a low potential.

  11. Synthesis of hydroxyapatite and structural refinement by X-ray diffraction

    International Nuclear Information System (INIS)

    Araujo, Jorge Correa de

    2007-01-01

    A sample of hydroxyapatite was synthesized and its crystalline structure was analyzed by X-ray diffraction by means of the Rietveld method. Two functions were used to fit the peak profiles, modified Voigt (TCHZ) and Pearson VII. The occupational factors and lattice parameters obtained by both models show that the sample does not contain relevant cationic substitutions. The interatomic distances from Ca1 to oxygens O1, O2 and O3 were adequate for a pure hydroxyapatite without defect at site Ca1. Besides, the use of multiple lines in planes (300) and (002) associated with the model Pearson VII resulted in good agreement with the TCHZ model with respect to the size-strain effects with an ellipsoidal shape of crystallites. In conclusion, the procedures adopted in the synthesis of hydroxyapatite produced a pure and crystalline material. The experimental results of transmission electron microscopy confirmed the predicted shape of crystals. (author)

  12. EVALUATION OF THE SYNTHESIS AND STRUCTURE OF NEW AZETIDIN-2-ONES OF FERULIC ACID.

    Science.gov (United States)

    Stan, Cătălina Daniela; Drăgan, Maria; Pânzariu, Andreea; Profire, Lenuţa

    2016-01-01

    To synthesize some new azetidin-2-ones of ferulic acid and to evaluate them from physicochemical and spectral point of view. The synthesis was carried out in several steps: (i) obtaining the ferulic acid chloride; (ii) obtaining the ferulic acid hydrazide with hydrazine hydrate (98%); (iii) condensation of ferulic acid hydrazide with different benzaldehydes (2-hydroxy-/2-nitro-/4-chloro-/4- fluoro-/4-bromo-benzaldehyde) in order to obtain the corresponding hydrazones; (iv) cy- clization of ferulic acid hydrazones with chloroacethyl chloride in freshly distilled toluene medium and in the presence of triethylamine, resulting in the corresponding azetidin-2-ones. Six new azetidin-2-ones of ferulic acid were synthesized. They were characterized in terms of their physicochemical properties and their structure was confirmed by IR and 1H-NMR spectroscopy. Six new azetidin-2-ones of ferulic acid were synthesized, physicochemically characterized and validated spectrally. A

  13. Synthesis and structural characterization of piperazino-modified DNA that favours hybridization towards DNA over RNA

    DEFF Research Database (Denmark)

    Skov, Joan; Bryld, Torsten; Lindegaard, Dorthe

    2011-01-01

    We report the synthesis of two C4'-modified DNA analogues and characterize their structural impact on dsDNA duplexes. The 4'-C-piperazinomethyl modification stabilizes dsDNA by up to 5°C per incorporation. Extension of the modification with a butanoyl-linked pyrene increases the dsDNA stabilization...... to a maximum of 9°C per incorporation. Using fluorescence, ultraviolet and nuclear magnetic resonance (NMR) spectroscopy, we show that the stabilization is achieved by pyrene intercalation in the dsDNA duplex. The pyrene moiety is not restricted to one intercalation site but rather switches between multiple...... sites in intermediate exchange on the NMR timescale, resulting in broad lines in NMR spectra. We identified two intercalation sites with NOE data showing that the pyrene prefers to intercalate one base pair away from the modified nucleotide with its linker curled up in the minor groove. Both...

  14. Synthesis, X-ray crystal structure and theoretical calculations of antileishmanial neolignan analogues

    International Nuclear Information System (INIS)

    Nascimento, Josenaide P. do; Santos, Lourivaldo S.; Carmo, Maria Carolina L. do; Brasil, Davi S.B.; Alves, Claudio N.; Santos, Regina Helena A.; Tozzo, Erica; Ferreira, Janaina G.

    2010-01-01

    The synthesis and X-ray crystal diffraction structure of two analogues of neolignans, 2-(4-chlorophenyl)-1-phenylethanone (20) and 2-[(4-chlorophenyl)thio]-1-(3,4-dimethoxyphenyl) propan-1-one (12) is described. The compound 12 presents activity against intracellular Leishmania donovani and Leishmania amazonensis amastigotes that cause cutaneous and visceral leishmaniasis. In addition, the density functional theory (DFT) with the B3LYP hybrid functional was employed to calculate a set of molecular descriptors for nineteen synthetic analogues of neolignans with antileishmanial activities. Afterwards, the stepwise discriminant analysis was performed to investigate possible relationship between the molecular descriptors and biological activities. Through this analysis the compounds were classified into two groups active and inactive according to their degree of biological activities, and the more important properties were charges on some key atoms, electronic affinity and ClogP. (author)

  15. Synthesis, X-ray crystal structure and theoretical calculations of antileishmanial neolignan analogues

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Josenaide P. do; Santos, Lourivaldo S.; Carmo, Maria Carolina L. do; Brasil, Davi S.B.; Alves, Claudio N., E-mail: nahum@ufpa.b [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Ciencias Exatas e Naturais; Santos, Regina Helena A.; Tozzo, Erica; Ferreira, Janaina G. [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2010-07-01

    The synthesis and X-ray crystal diffraction structure of two analogues of neolignans, 2-(4-chlorophenyl)-1-phenylethanone (20) and 2-[(4-chlorophenyl)thio]-1-(3,4-dimethoxyphenyl) propan-1-one (12) is described. The compound 12 presents activity against intracellular Leishmania donovani and Leishmania amazonensis amastigotes that cause cutaneous and visceral leishmaniasis. In addition, the density functional theory (DFT) with the B3LYP hybrid functional was employed to calculate a set of molecular descriptors for nineteen synthetic analogues of neolignans with antileishmanial activities. Afterwards, the stepwise discriminant analysis was performed to investigate possible relationship between the molecular descriptors and biological activities. Through this analysis the compounds were classified into two groups active and inactive according to their degree of biological activities, and the more important properties were charges on some key atoms, electronic affinity and ClogP. (author)

  16. Mesoporous Structure Control of Silica in Room-Temperature Synthesis under Basic Conditions

    Directory of Open Access Journals (Sweden)

    Jeong Wook Seo

    2015-01-01

    Full Text Available Various types of mesoporous silica, such as continuous cubic-phase MCM-48, hexagonal-phase MCM-41, and layer-phase spherical silica particles, have been synthesized at room temperature using cetyltrimethylammonium bromide as a surfactant, ethanol as a cosurfactant, tetraethyl orthosilicate as a silica precursor, and ammonia as a condensation agent. Special care must be taken both in the filtering of the resultant solid products and in the drying process. In the drying process, further condensation of the silica after filtering was induced. As the surfactant and cosurfactant concentrations in the reaction mixture increased and the NH3 concentration decreased, under given conditions, continuous cubic MCM-48 and layered silica became the dominant phases. A cooperative synthesis mechanism, in which both the surfactant and silica were involved in the formation of mesoporous structures, provided a good explanation of the experimental results.

  17. Synthesis and computer-aided structural investigation of potentially photochromic spirooxazines

    International Nuclear Information System (INIS)

    Chi, L.

    2000-03-01

    Quantum mechanical methods, PPP-MO and ZINDO, were used to predict the electronic spectra of the ring-opened forms and ring-closed forms respectively of a series of spirooxazines. Molecular mechanics was used to optimise the molecular geometry and to calculate the molecular final energy (steric energy) using the MM2 force field method. An all-valence-electron quantum mechanical method was employed to calculate the heats of formation using AM1 parameters, and the data were used to provide a measure of the stability of the molecules. This computer-aided structural investigation has provided an enhanced understanding of the spirooxazine system and methods with the potential to predict photochromic behaviour have emerged. The synthesis of a series of heterocyclic analogues of the well-known spironaphthoxazines based on quinolines, coumarin and pyrazolones were attempted. The properties of the compounds obtained were correlated with the results of the calculations. (author)

  18. Tungsten disilicide (WSi{sub 2}). Synthesis, characterization, and prediction of new crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Lukovic, Jelena; Zagorac, Dejan; Zagorac, Jelena; Jordanov, Dragana; Matovic, Branko [Institute of Nuclear Sciences Vinca, Materials Science Laboratory, University of Belgrade (Serbia); Materials Science Laboratory, Center for the Synthesis, Processing and Characterization of Materials for Use in Extreme Conditions, Belgrade (Serbia); Schoen, J. Christian [Materials Science Laboratory, Max Planck Institute for Solid State Research, Stuttgart (Germany); Volkov-Husovic, Tatjana [Faculty of Technology and Metallurgy, Department for Metallurgical Engineering, University of Belgrade (Serbia)

    2017-12-13

    Transition metal silicides have attracted great attention due to their potential applications in microelectronics, ceramics, and the aerospace industry. In this study, experimental and theoretical investigations of tungsten based silicides were performed. Tungsten disilicide (WSi{sub 2}) was synthesized by simple thermal treatment at 1350 C for 4 h in an argon atmosphere. These optimal synthesis conditions were obtained by variation of temperatures and times of heating, and the structure of the final synthesized compound was determined by XRPD analysis. In addition, new modifications for WSi{sub 2} were proposed and investigated using first-principles calculations within density-functional theory (DFT). Both LDA and PBE calculations show excellent agreement with experimental observations and previous calculations for the existing modifications, where available. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Isolation, Structure Elucidation and Total Synthesis of Lajollamide A from the Marine Fungus Asteromyces cruciatus

    Directory of Open Access Journals (Sweden)

    Johannes F. Imhoff

    2012-12-01

    Full Text Available The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1, along with the known compounds regiolone (2, hyalodendrin (3, gliovictin (4, 1N-norgliovicitin (5, and bis-N-norgliovictin (6. The planar structure of lajollamide A (1 was determined by Nuclear Magnetic Resonance (NMR spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1 was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1 of the l-leucine and l-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.

  20. Isolation, Structure Elucidation and Total Synthesis of Lajollamide A from the Marine Fungus Asteromyces cruciatus

    Science.gov (United States)

    Gulder, Tobias A. M.; Hong, Hanna; Correa, Jhonny; Egereva, Ekaterina; Wiese, Jutta; Imhoff, Johannes F.; Gross, Harald

    2012-01-01

    The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), 1N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the L-leucine and L-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems. PMID:23342379

  1. Trends in computerized structural analysis and synthesis; Proceedings of the Symposium, Washington, D.C., October 30-November 1, 1978

    Science.gov (United States)

    Noor, A. K. (Editor); Mccomb, H. G., Jr.

    1978-01-01

    The subjects considered are related to future directions of structural applications and potential of new computing systems, advances and trends in data management and engineering software development, advances in applied mathematics and symbolic computing, computer-aided instruction and interactive computer graphics, nonlinear analysis, dynamic analysis and transient response, structural synthesis, structural analysis and design systems, advanced structural applications, supercomputers, numerical analysis, and trends in software systems. Attention is given to the reliability and optimality of the finite element method, computerized symbolic manipulation in structural mechanics, a standard computer graphics subroutine package, and a drag method as a finite element mesh generation scheme.

  2. Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure

    Energy Technology Data Exchange (ETDEWEB)

    Rubina, M.S.; Kamitov, E.E. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russian Federation (Russian Federation); Zubavichus, Ya. V.; Peters, G.S. [National Research center «Kurchatov Institute», Moscow, 123182 Russian Federation (Russian Federation); Naumkin, A.V. [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russian Federation (Russian Federation); Suzer, S. [Department of Chemistry, Bilkent University, Ankara, 06800 Turkey (Turkey); Vasil’kov, A.Yu., E-mail: alexandervasilkov@yandex.ru [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991 Russian Federation (Russian Federation)

    2016-03-15

    Graphical abstract: - Highlights: • Biocompatible collagen-chitosan scaffolds were modified by Au and Ag nanoparticles via the metal-vapor synthesis. • Structural and morphological parameters of the nanocomposites were assessed using a set of modern instrumental techniques, including electron microscopy, X-ray diffraction, small-angle X-ray scattering, EXAFS, XPS. • Potential application of the nanocomposites are envisaged. - Abstract: Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains.

  3. Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure

    International Nuclear Information System (INIS)

    Rubina, M.S.; Kamitov, E.E.; Zubavichus, Ya. V.; Peters, G.S.; Naumkin, A.V.; Suzer, S.; Vasil’kov, A.Yu.

    2016-01-01

    Graphical abstract: - Highlights: • Biocompatible collagen-chitosan scaffolds were modified by Au and Ag nanoparticles via the metal-vapor synthesis. • Structural and morphological parameters of the nanocomposites were assessed using a set of modern instrumental techniques, including electron microscopy, X-ray diffraction, small-angle X-ray scattering, EXAFS, XPS. • Potential application of the nanocomposites are envisaged. - Abstract: Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains.

  4. Radio Frequency Plasma Synthesis of Boron Nitride Nanotubes (BNNTs) for Structural Applications. Part II

    Science.gov (United States)

    Hales, Stephen J.; Alexa, Joel A.; Jensen, Brian J.

    2016-01-01

    Boron nitride nanotubes (BNNTs) are more thermally and chemically compatible with metal- and ceramic-matrix composites than carbon nanotubes (CNTs). The lack of an abundant supply of defect-free, high-aspect-ratio BNNTs has hindered development as reinforcing agents in structural materials. Recent activities at the National Research Council - Canada (NRC-C) and the University of California - Berkeley (UC-B) have resulted in bulk synthesis of few-walled, small diameter BNNTs. Both processes employ induction plasma technology to create boron vapor and highly reactive nitrogen species at temperatures in excess of 8000 K. Subsequent recombination under controlled cooling conditions results in the formation of BNNTs at a rate of 20 g/hr and 35 g/hr, respectively. The end product tends to consist of tangled masses of fibril-, sheet-, and cotton candy-like materials, which accumulate within the processing equipment. The radio frequency plasma spray (RFPS) facility at NASA Langley (LaRC), developed for metallic materials deposition, has been re-tooled for in-situ synthesis of BNNTs. The NRC-C and UC-B facilities comprise a 60 kW RF torch, a reactor with a stove pipe geometry, and a filtration system. In contrast, the LaRC facility has a 100 kW torch mounted atop an expansive reaction chamber coupled with a cyclone separator. The intent is to take advantage of both the extra power and the equipment configuration to simultaneously produce and gather BNNTs in a macroscopic form amenable to structural material applications.

  5. Deuterated detergents for structural and functional studies of membrane proteins: Properties, chemical synthesis and applications.

    Science.gov (United States)

    Hiruma-Shimizu, Kazumi; Shimizu, Hiroki; Thompson, Gary S; Kalverda, Arnout P; Patching, Simon G

    2015-01-01

    Detergents are amphiphilic compounds that have crucial roles in the extraction, purification and stabilization of integral membrane proteins and in experimental studies of their structure and function. One technique that is highly dependent on detergents for solubilization of membrane proteins is solution-state NMR spectroscopy, where detergent micelles often serve as the best membrane mimetic for achieving particle sizes that tumble fast enough to produce high-resolution and high-sensitivity spectra, although not necessarily the best mimetic for a biomembrane. For achieving the best quality NMR spectra, detergents with partial or complete deuteration can be used, which eliminate interfering proton signals coming from the detergent itself and also eliminate potential proton relaxation pathways and strong dipole-dipole interactions that contribute line broadening effects. Deuterated detergents have also been used to solubilize membrane proteins for other experimental techniques including small angle neutron scattering and single-crystal neutron diffraction and for studying membrane proteins immobilized on gold electrodes. This is a review of the properties, chemical synthesis and applications of detergents that are currently commercially available and/or that have been synthesized with partial or complete deuteration. Specifically, the detergents are sodium dodecyl sulphate (SDS), lauryldimethylamine-oxide (LDAO), n-octyl-β-D-glucoside (β-OG), n-dodecyl-β-D-maltoside (DDM) and fos-cholines including dodecylphosphocholine (DPC). The review also considers effects of deuteration, detergent screening and guidelines for detergent selection. Although deuterated detergents are relatively expensive and not always commercially available due to challenges associated with their chemical synthesis, they will continue to play important roles in structural and functional studies of membrane proteins, especially using solution-state NMR.

  6. Synthesis of Titania-Silica Materials by Sol-Gel

    Directory of Open Access Journals (Sweden)

    Rubia F. S. Lenza

    2002-10-01

    Full Text Available In this work TiO2-SiO2 glasses containing as much as 20 mol % of TiO2 were prepared via sol-gel process using titanium and silicon alkoxides, in the presence of chlorine, in the form of titanium tetrachloride or HCl. The gels were heat-treated until 800 °C. X-ray diffraction and Fourier transform infrared spectroscopy were used to understand the structural properties of TiO2-SiO2 oxides calcined at different temperatures and to evaluate the homogeneity of these materials. The degree of the compactness of the silica network is inferred from the frequency of the asymmetric stretching vibrations of Si-O-Si bonds. Formation of Si-O-Ti bridges, as monitored by the intensity of characteristic 945 cm-1 ¾ 960 cm-1 vibration, is particularly prominent if the method of basic two-step prehydrolysis of silicon alkoxide, addition of titanium alkoxide and completion of hydrolysis was used.

  7. Dispersed metal cluster catalysts by design. Synthesis, characterization, structure, and performance

    Energy Technology Data Exchange (ETDEWEB)

    Arslan, Ilke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A. [Univ. of Alabama, Tuscaloosa, AL (United States); Gates, Bruce C. [Univ. of California, Davis, CA (United States); Katz, Alexander [Univ. of California, Berkeley, CA (United States)

    2015-09-30

    To understand the class of metal cluster catalysts better and to lay a foundation for the prediction of properties leading to improved catalysts, we have synthesized metal catalysts with well-defined structures and varied the cluster structures and compositions systematically—including the ligands bonded to the metals. These ligands include supports and bulky organics that are being tuned to control both the electron transfer to or from the metal and the accessibility of reactants to influence catalytic properties. We have developed novel syntheses to prepare these well-defined catalysts with atomic-scale control the environment by choice and placement of ligands and applied state-of-the art spectroscopic, microscopic, and computational methods to determine their structures, reactivities, and catalytic properties. The ligands range from nearly flat MgO surfaces to enveloping zeolites to bulky calixarenes to provide controlled coverages of the metal clusters, while also enforcing unprecedented degrees of coordinative unsaturation at the metal site—thereby facilitating bonding and catalysis events at exposed metal atoms. With this wide range of ligand properties and our arsenal of characterization tools, we worked to achieve a deep, fundamental understanding of how to synthesize robust supported and ligand-modified metal clusters with controlled catalytic properties, thereby bridging the gap between active site structure and function in unsupported and supported metal catalysts. We used methods of organometallic and inorganic chemistry combined with surface chemistry for the precise synthesis of metal clusters and nanoparticles, characterizing them at various stages of preparation and under various conditions (including catalytic reaction conditions) and determining their structures and reactivities and how their catalytic properties depend on their compositions and structures. Key characterization methods included IR, NMR, and EXAFS spectroscopies to identify

  8. Immobilized Cu (II)—Amino Acid Complexes as Prospective Highly Efficient Catalytic Materials: Synthesis, Structural Characterization and Catalytic Activities

    Science.gov (United States)

    Pálinkó, István; Ordasi, Adrien; Kiss, János T.; Labádi, Imre

    2008-11-01

    In this work the covalent anchoring of N-or C-protected Cu(II)—L-tyrosine complexes onto a swellable resin or surface-modified silica gel is described. Experimental conditions (solvents, the availability of ligands) of the synthesis were varied; the structures (by IR spectroscopy) and the superoxide dismutase activities of the anchored complexes were studied.

  9. Structural and Optical Properties of White Light Emitting ZnS:Mn(2+) Nanoparticles at Different Synthesis Temperatures.

    Science.gov (United States)

    Bindu, K R; Anila, E I

    2015-07-01

    We report of the synthesis and characterisation of white emitting ZnS:Mn(2+) nanoparticles. The spectroscopic properties and the crystal structure of Mn doped ZnS nanoparticles are studied here to provide a better understanding on how the luminescence emission and the crystalline composition are influenced by the synthesis temperature. The synthesis of the samples were carried out by the simple wet chemical precipitation method. The influence of synthesis temperature on structure and optical properties were studied at constant Mn concentration. The nanoparticles were structurally characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The XRD studies show the phase singularity of Mn doped ZnS particles having zinc-blende (cubic) structure at all temperatures. The band gap of the doped samples are red shifted with temperature. Electron Paramagnetic Resonance (EPR) spectra exhibited resonance signals, characteristic of Mn(2+). Incorporation of Mn in the ZnS nanoparticles was confirmed by Inductively Coupled Plasma- Atomic Emission Spectroscopic studies (ICP-AES). The samples show an efficient emission of yellow-orange light centred at 590 nm which is characteristic of Mn(2+) along with a blue emission at 435 nm due to sulfur vacancy. The overall emission is white at all temperatures with CIE co-ordinates in close agreement with achromatic white.

  10. Non-metallocene rare-earth organometallic derivatives: synthesis, structure and application in the catalysis of transformations of unsaturated substrates

    International Nuclear Information System (INIS)

    Trifonov, A A

    2007-01-01

    The post-metallocene period of development of the chemistry of rare-earth organometallic compounds is analysed. The synthesis, structures and reactivities of complexes containing metal-carbon and metal-hydrogen bonds and stabilised by N-, P, and O-donor ligands are considered. The catalytic activities of these compounds in alkene polymerisation, hydroamination, hydrosilylation and hydroboration are discussed.

  11. Non-metallocene rare-earth organometallic derivatives: synthesis, structure and application in the catalysis of transformations of unsaturated substrates

    Energy Technology Data Exchange (ETDEWEB)

    Trifonov, A A [G.A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2007-11-30

    The post-metallocene period of development of the chemistry of rare-earth organometallic compounds is analysed. The synthesis, structures and reactivities of complexes containing metal-carbon and metal-hydrogen bonds and stabilised by N-, P, and O-donor ligands are considered. The catalytic activities of these compounds in alkene polymerisation, hydroamination, hydrosilylation and hydroboration are discussed.

  12. Non-metallocene rare-earth organometallic derivatives: synthesis, structure and application in the catalysis of transformations of unsaturated substrates

    Science.gov (United States)

    Trifonov, A. A.

    2007-11-01

    The post-metallocene period of development of the chemistry of rare-earth organometallic compounds is analysed. The synthesis, structures and reactivities of complexes containing metal-carbon and metal-hydrogen bonds and stabilised by N-, P, and O-donor ligands are considered. The catalytic activities of these compounds in alkene polymerisation, hydroamination, hydrosilylation and hydroboration are discussed.

  13. Structural and elemental influence from various MOFs on the performance of Fe@C catalysts for Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Wezendonk, T.A.; Warringa, Quirinus S E; Santos, Vera P.; Chojecki, Adam; Ruitenbeek, Matthijs; Meima, Garry; Makkee, M.; Kapteijn, F.; Gascon Sabate, J.

    2017-01-01

    The structure and elementary composition of various commercial Fe-based MOFs used as precursors for Fischer-Tropsch synthesis (FTS) catalysts have a large influence on the high-temperature FTS activity and selectivity of the resulting Fe on carbon composites. The selected Fe-MOF topologies

  14. Synthesis by irradiation and mechanism and structural characterization study of high melt strength polypropylene

    International Nuclear Information System (INIS)

    Lugao, Ademar Benevolo

    2004-01-01

    Polypropylene molecular structure is made only by linear molecules interacting by weak forces. The resulting PP has very low melt strength (MS). MS is important to make feasible to process PP by all the transformation technologies based on the free expansion of the melt. The aim of this work was to develop a new process to synthesize PP with crosslinks and/or long chain branches, known as High Melt Strength Polypropylene (HMSPP) and to characterize its structure and synthesis mechanism. HMSPP was obtained by the irradiation of PP under a crosslinking (acetylene) atmosphere or inert or oxidative one, followed by thermal treatment for radical recombination and thermal treatment for annihilation of the remaining radicals under reactive or inert atmosphere. The results from rheological characterization showed that the highest levels of MS were obtained by conducting irradiation and thermal treatments under crosslinking atmospheres. The results for the elucidation of reaction mechanism by electron spin resonance (ESR) showed that acetylene irradiation is effective in promoting the creation of double bonds, based on the formation of polyenil radicals. The results of structural unraveling showed that radiation promotes predominantly the degradation of atactic molecules or molecules with atactic defects. These results support the hypothesis of formation of branched PP molecules based on the reaction of those fragments with the double bonds created in the PP molecules. (author)

  15. Aperture synthesis observations of NH3 in OMC-1 - Filamentary structures around Orion-KL

    International Nuclear Information System (INIS)

    Murata, Yasuhiro; Kawabe, Ryohei; Ishiguro, Masato; Morita, Kohichiro; Kasuga, Takashi

    1990-01-01

    Aperture synthesis observations of the Orion molecular cloud 1 (OMC-1) have been made in NH 3 (1, 1) and (2, 2) emission at 23.7 GHz, using the Nobeyama Millimeter Array (NMA), and obtained 16 arcsec resolution maps for OMC-1 and 8 arcsec resolution maps for the Orion-KL region. Filamentary structures extending over 0.5 pc from the Orion-KL region to the north and northwest directions were found. These structures are associated with the H2 finger structures and Herbig-Haro objects which are located at the blue-shifted side of the bipolar molecular outflow. The results suggest that these filaments are ambient molecular cloudlets with shocked surfaces caused by the strong stellar wind from the Orion-KL region. The 8 arcsec resolution NH 3 (2, 2) maps show the extended features around the hot core of Orion-KL. These extended features correspond to the rotating disk and shocked shell associated with the bipolar molecular outflow. 37 refs

  16. Synthesis, structure, and optical activity of HPM-1, a pure silica chiral zeolite.

    Science.gov (United States)

    Rojas, Alex; Arteaga, Oriol; Kahr, Bart; Camblor, Miguel A

    2013-08-14

    2-Ethyl-1,3,4-trimethylimidazolium is a poor organic structure-directing agent in the synthesis of pure silica zeolites using fluoride as a mineralizer at 150 °C. Under these conditions only ill-crystallized solids are obtained after long hydrothermal treatments (several weeks). It disappoints despite its relatively large size, conformational rigidity, and intermediate hydrophilic/hydrophobic character, attributes which would qualify it as a promising structure-directing agent, according to prior investigations. By raising the crystallization temperature to 175 °C under otherwise identical conditions, crystallization is dramatically accelerated. Depending on the water/silica ratio and crystallization time, two different materials are obtained: the recently reported pure silica polymorph of the chiral STW-type zeolite, HPM-1, and the new layered organosilicate, HPM-2. Prolonged heating transforms these phases into the small-pore ITW-type zeolite, while no signs of the SOF-type zeolite (formally built from the same layers as STW) was found. A complete physicochemical and structural characterization of the as-made chiral HPM-1 zeolite is provided, and the proposed stabilization of this zeolite by polarization of the Si-O bond is supported by the observed deviation from tetrahedrality. HPM-1 is optically active, and a study of several crystallites by Mueller matrix microscopy shows that their optical activity can be individually measured and that this technique could be useful for the assessment of the enantiomeric purity of a microcrystalline powder.

  17. Using a precursor in lamellar structure for the synthesis of uniform ZnS nanocrystals

    KAUST Repository

    Xu, Xinjiang

    2011-11-12

    Uniform ZnS nanocrystals of about 15 nm were prepared through a low temperature hydrothermal approach by treating Zn-PhPO nanosheets with Na 2S aqueous solution. Both the precursor and the final product were studied by the means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The photo-luminescent spectrum of the synthesized ZnS nanocrystals showed their good crystalline nature. Based on this study, the precursor structure-controlling effect was discussed, and in addition, the relevant factors possibly affecting the particle formation and the growth possessed were applied in the discussion to interpret the transformation mechanism. Further research showed that both the structure characters of the precursors and the mass transportation which occurred during the synthesis greatly affected the morphology and organization state of the final products. This research may provide some facts on the structure-controlling approaches along with a general method for the preparation of uniform sulfide nanocrystals. © Springer Science+Business Media B.V. 2011.

  18. Radio Frequency Plasma Synthesis of Boron Nitride Nanotubes (BNNTs) for Structural Applications: Part I

    Science.gov (United States)

    Hales, Stephen J.; Alexa, Joel A.; Jensen, Brian J.; Thomsen, Donald L.

    2016-01-01

    It is evident that nanotubes, such as carbon, boron nitride and even silicon, offer great potential for many aerospace applications. The opportunity exists to harness the extremely high strength and stiffness exhibited by high-purity, low-defect nanotubes in structural materials. Even though the technology associated with carbon nanotube (CNT) development is mature, the mechanical property benefits have yet to be fully realized. Boron nitride nanotubes (BNNTs) offer similar structural benefits, but exhibit superior chemical and thermal stability. A broader range of potential structural applications results, particularly as reinforcing agents for metal- and ceramic- based composites. However, synthesis of BNNTs is more challenging than CNTs mainly because of the higher processing temperatures required, and mass production techniques have yet to emerge. A promising technique is radio frequency plasma spray (RFPS), which is an inductively coupled, very high temperature process. The lack of electrodes and the self- contained, inert gas environment lend themselves to an ultraclean product. It is the aim of this White Paper to survey the state of the art with regard to nano-material production by analyzing the pros and cons of existing methods. The intention is to combine the best concepts and apply the NASA Langley Research Center (LaRC) RFPS facility to reliably synthesize large quantities of consistent, high-purity BNNTs.

  19. The crystal structure of escherichia coli MoaB suggests a probable role in molybdenum cofactor synthesis

    International Nuclear Information System (INIS)

    Sanishvili, R.; Beasley, S.; Skarina, T; Glesne, D; Joachimiak, A; Edwards, A; Savchenko, A.; Univ. Health Network; Univ. of Toronto

    2004-01-01

    The crystal structure of Escherichia coli MoaB was determined by multiwavelength anomalous diffraction phasing and refined at 1.6 Angstrom resolution. The molecule displayed a modified Rossman fold. MoaB is assembled into a hexamer composed of two trimers. The monomers have high structural similarity with two proteins, MogA and MoeA, from the molybdenum cofactor synthesis pathway in E. Coli, as well as with domains of mammalian gephyrin and plant Cnx1, which are also involved in molybdopterin synthesis. Structural comparison between these proteins and the amino acid conservation patterns revealed a putative active site in MoaB. The structural analysis of this site allowed to advance several hypothesis which can be tested in further studies

  20. Synthesis of magnesium- and manganese-doped hydroxyapatite structures assisted by the simultaneous incorporation of strontium

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Mirna Pereira [Laboratório de Biomateriais, P" 2CEM/UFS, Av. Marechal Rondon, s/n, São Cristóvão 49100-000, Sergipe (Brazil); Dulce de Almeida Soares, Gloria [Dep. de Eng. Metal. e de Materiais, COPPE/UFRJ, CP 68505, Rio de Janeiro 21941-972 (Brazil); Dentzer, Joseph; Anselme, Karine [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS UMR7361, Université de Haute-Alsace, 15, rue Jean Starcky, BP 2488, 68057 Mulhouse (France); Sena, Lídia Ágata de; Kuznetsov, Alexei [Divisão de Metrologia de Materiais, Inmetro, Av. N. Sra. das Graças, 50, Duque de Caxias 25250-020, Rio de Janeiro (Brazil); Santos, Euler Araujo dos, E-mail: euler@ufs.br [Laboratório de Biomateriais, P" 2CEM/UFS, Av. Marechal Rondon, s/n, São Cristóvão 49100-000, Sergipe (Brazil)

    2016-04-01

    Samples of crystalline hydroxyapatite (HA) with and without the addition of individual Mg{sup 2+}, Mn{sup 2+} and Sr{sup 2+} ions and samples with the addition of all three ions simultaneously were prepared using the precipitation method in an aqueous medium. Chemical, structural, spectroscopic and thermophysical analyses of the synthesized samples were conducted. The obtained results indicate that Sr{sup 2+} ions were easily incorporated into the HA crystal structure, whereas it was difficult to incorporate Mg{sup 2+} and Mn{sup 2+} ions into the HA lattice when these ions were individually introduced into the samples. The synthesis of HA with Mg{sup 2+} or Mn{sup 2+} ions is characterized by the formation of HA with a low concentration of doping elements that is outweighed by the amount of these atoms present in less biocompatible phases that formed simultaneously. However, the incorporation of Sr{sup 2+} along with Mg{sup 2+} and Mn{sup 2+} ions into the samples allowed for the synthesis of HA with considerably higher concentrations of Mg{sup 2+} and Mn{sup 2+} in the crystal lattice. - Graphical abstract: Sr{sup 2+} ions were easily incorporated into the HA lattice, whereas Mg{sup 2+} and Mn{sup 2+} ions were hardly retained in the HA structure after heating to 1000 °C when they were individually incorporated in the samples. Nevertheless, co-substitution with Sr{sup 2+} ions allowed for better fixation of the Mg{sup 2+} and Mn{sup 2+} ions into the HA lattice. - Highlights: • Mg{sup 2+} and Mn{sup 2+} ions have a great difficulty being stabilized in the apatite lattice. • Sr{sup 2+} ions can stabilize Mg{sup 2+} and Mn{sup 2+} in the hydroxyapatite structure. • Except for Mn{sup 2+}, Sr{sup 2+} and Mg{sup 2+} obstruct the release of CO{sub 2}.

  1. Development of a Probabilistic Dynamic Synthesis Method for the Analysis of Nondeterministic Structures

    Science.gov (United States)

    Brown, A. M.

    1998-01-01

    Accounting for the statistical geometric and material variability of structures in analysis has been a topic of considerable research for the last 30 years. The determination of quantifiable measures of statistical probability of a desired response variable, such as natural frequency, maximum displacement, or stress, to replace experience-based "safety factors" has been a primary goal of these studies. There are, however, several problems associated with their satisfactory application to realistic structures, such as bladed disks in turbomachinery. These include the accurate definition of the input random variables (rv's), the large size of the finite element models frequently used to simulate these structures, which makes even a single deterministic analysis expensive, and accurate generation of the cumulative distribution function (CDF) necessary to obtain the probability of the desired response variables. The research presented here applies a methodology called probabilistic dynamic synthesis (PDS) to solve these problems. The PDS method uses dynamic characteristics of substructures measured from modal test as the input rv's, rather than "primitive" rv's such as material or geometric uncertainties. These dynamic characteristics, which are the free-free eigenvalues, eigenvectors, and residual flexibility (RF), are readily measured and for many substructures, a reasonable sample set of these measurements can be obtained. The statistics for these rv's accurately account for the entire random character of the substructure. Using the RF method of component mode synthesis, these dynamic characteristics are used to generate reduced-size sample models of the substructures, which are then coupled to form system models. These sample models are used to obtain the CDF of the response variable by either applying Monte Carlo simulation or by generating data points for use in the response surface reliability method, which can perform the probabilistic analysis with an order of

  2. Synthesis and structural studies of Na2 O–ZnO–ZnF2 –B2 O3 ...

    Indian Academy of Sciences (India)

    Wintec

    Due to this the structure of glass is expected to be diffe- rent from that of alkali borate glasses (Kim and Bray. 1974; Munia et al 1999). In the present study, we report the synthesis and structural studies of Na2O–ZnO–ZnF2–. B2O3 oxyfluoride glasses and study the role of intersub- stitution of ZnO by ZnF2. 2. Experimental.

  3. Design, synthesis, and characterization of new phosphazene related materials, and study the structure property correlations

    Science.gov (United States)

    Tian, Zhicheng

    The work described in this thesis is divided into three major parts, and all of which involve the exploration of the chemistry of polyphosphazenes. The first part (chapters 2 and 3) of my research is synthesis and study polyphoshazenes for biomedical applications, including polymer drug conjugates and injectable hydrogels for drug or biomolecule delivery. The second part (chapters 4 and 5) focuses on the synthesis of several organic/inorganic hybrid polymeric structures, such as diblock, star, brush and palm tree copolymers using living cationic polymerization and atom transfer radical polymerization techniques. The last part (chapters 6 and 7) is about exploratory synthesis of new polymeric structures with fluorinated side groups or cycloaliphatic side groups, and the study of new structure property relationships. Chapter 1 is an outline of the fundamental concepts for polymeric materials, as such the history, important definitions, and some introductory material for to polymer chemistry and physics. The chemistry and applications of phopshazenes is also briefly described. Chapter 2 is a description of the design, synthesis, and characterization of development of a new class of polymer drug conjugate materials based on biodegradable polyphosphazenes and antibiotics. Poly(dichlorophosphazene), synthesized by a thermal ring opening polymerization, was reacted with up to 25 mol% of ciprofloxacin or norfloxacin and three different amino acid esters (glycine, alanine, or phenylalanine) as cosubstituents via macromolecular substitutions. Nano/microfibers of several selected polymers were prepared by an electrospinning technique. Chapter 3 is concerned with the development of a class of injectable and biodegradable hydrogels based on water-soluble poly(organophosphazenes) containing oligo(ethylene glycol) methyl ethers and glycine ethyl esters. The hydrogels can be obtained by mixing alpha-cyclodextrin aqueous solution and poly(organophosphazenes) aqueous solution in

  4. Methanol synthesis on ZnO(0001¯). IV. Reaction mechanisms and electronic structure

    International Nuclear Information System (INIS)

    Frenzel, Johannes; Marx, Dominik

    2014-01-01

    Methanol synthesis from CO and H 2 over ZnO, which requires high temperatures and high pressures giving rise to a complex interplay of physical and chemical processes over this heterogeneous catalyst surface, is investigated using ab initio simulations. The redox properties of the surrounding gas phase are known to directly impact on the catalyst properties and thus, set the overall catalytic reactivity of this easily reducible oxide material. In Paper III of our series [J. Kiss, J. Frenzel, N. N. Nair, B. Meyer, and D. Marx, J. Chem. Phys. 134, 064710 (2011)] we have qualitatively shown that for the partially hydroxylated and defective ZnO(0001 ¯ ) surface there exists an intricate network of surface chemical reactions. In the present study, we employ advanced molecular dynamics techniques to resolve in detail this reaction network in terms of elementary steps on the defective surface, which is in stepwise equilibrium with the gas phase. The two individual reduction steps were investigated by ab initio metadynamics sampling of free energy landscapes in three-dimensional reaction subspaces. By also sampling adsorption and desorption processes and thus molecular species that are in the gas phase but close to the surface, our approach successfully generated several alternative pathways of methanol synthesis. The obtained results suggest an Eley-Rideal mechanism for both reduction steps, thus involving “near-surface” molecules from the gas phase, to give methanol preferentially over a strongly reduced catalyst surface, while important side reactions are of Langmuir-Hinshelwood type. Catalyst re-reduction by H 2 stemming from the gas phase is a crucial process after each reduction step in order to maintain the catalyst's activity toward methanol formation and to close the catalytic cycle in some reaction channels. Furthermore, the role of oxygen vacancies, side reactions, and spectator species is investigated and mechanistic details are discussed based on

  5. Structural design, synthesis and structure-activity relationships of thiazolidinones with enhanced anti-Trypanosoma cruzi activity.

    Science.gov (United States)

    Moreira, Diogo Rodrigo Magalhães; Leite, Ana Cristina Lima; Cardoso, Marcos Verissimo Oliveira; Srivastava, Rajendra Mohan; Hernandes, Marcelo Zaldini; Rabello, Marcelo Montenegro; da Cruz, Luana Faria; Ferreira, Rafaela Salgado; de Simone, Carlos Alberto; Meira, Cássio Santana; Guimaraes, Elisalva Teixeira; da Silva, Aline Caroline; dos Santos, Thiago André Ramos; Pereira, Valéria Rêgo Alves; Soares, Milena Botelho Pereira

    2014-01-01

    Pharmacological treatment of Chagas disease is based on benznidazole, which displays poor efficacy when administered during the chronic phase of infection. Therefore, the development of new therapeutic options is needed. This study reports on the structural design and synthesis of a new class of anti-Trypanosoma cruzi thiazolidinones (4 a-p). (2-[2-Phenoxy-1-(4-bromophenyl)ethylidene)hydrazono]-5-ethylthiazolidin-4-one (4 h) and (2-[2-phenoxy-1-(4-phenylphenyl)ethylidene)hydrazono]-5-ethylthiazolidin-4-one (4 l) were the most potent compounds, resulting in reduced epimastigote proliferation and were toxic for trypomastigotes at concentrations below 10 μM, while they did not display host cell toxicity up to 200 μM. Thiazolidinone 4 h was able to reduce the in vitro parasite burden and the blood parasitemia in mice with similar potency to benznidazole. More importantly, T. cruzi infection reduction was achieved without exhibiting mouse toxicity. Regarding the molecular mechanism of action, these thiazolidinones did not inhibit cruzain activity, which is the major trypanosomal protease. However, investigating the cellular mechanism of action, thiazolidinones altered Golgi complex and endoplasmic reticulum (ER) morphology, produced atypical cytosolic vacuoles, as well as induced necrotic parasite death. This structural design employed for the new anti-T. cruzi thiazolidinones (4 a-p) led to the identification of compounds with enhanced potency and selectivity compared to first-generation thiazolidinones. These compounds did not inhibit cruzain activity, but exhibited strong antiparasitic activity by acting as parasiticidal agents and inducing a necrotic parasite cell death. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Synthesis and structural features of resorcinol–formaldehyde resin chars containing nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Galaburda, M.V., E-mail: mashagayeva@yandex.ua [Chuiko Institute of Surface Chemistry, 17 General Naumov Str., Kyiv 03164 (Ukraine); Bogatyrov, V.M. [Chuiko Institute of Surface Chemistry, 17 General Naumov Str., Kyiv 03164 (Ukraine); Skubiszewska-Zięba, J. [Faculty of Chemistry, Maria Curie-Skłodowska University, Maria Curie-Sklodowska Sq.3, 20-031 Lublin (Poland); Oranska, O.I. [Chuiko Institute of Surface Chemistry, 17 General Naumov Str., Kyiv 03164 (Ukraine); Sternik, D. [Faculty of Chemistry, Maria Curie-Skłodowska University, Maria Curie-Sklodowska Sq.3, 20-031 Lublin (Poland); Gun’ko, V.M. [Chuiko Institute of Surface Chemistry, 17 General Naumov Str., Kyiv 03164 (Ukraine)

    2016-01-01

    Graphical abstract: - Highlights: • Facile synthesis of the Ni-doped carbon sorbents via carbonization of resorcinol–formaldehyde polymers/nickel(II) acetate mixtures in the inert atmosphere. • Effects of Ni content, as well as water volume and temperature treatment on the morphology and texture of the chars. • Ni/C composites are characterized by a core–shell structure with well-crystallized graphitic shells. • Ni content influences the structure of the carbon. • Nickel-doped carbon nanocomposites were used as a magnetically separable adsorbent. - Abstract: A series of meso- and microporous carbons containing magnetic Ni nanoparticles (Ni/C) with a variety of Ni loadings were synthesized by a simple one-pot procedure through carbonization of resorcinol–formaldehyde polymers containing various amounts of nickel(II) acetate. Such composite materials were characterized by N{sub 2} sorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscope (TEM). The XRD patterns reveal peaks corresponding to face centered cubic nickel with the average size of crystallites of 17–18 nm. SEM and TEM results reveal that the formation of the nanoparticles took place mainly in the carbon spheres (1–2 μm in size) and on the outer surface as well. The as-prepared composites are characterized by a core–shell structure with well-crystallized graphitic shells about 8–15 nm in thickness. The Raman spectra show that Ni content influences the structure of the carbon. It was also shown that the morphology (particle shape and sizes) and porosity (pore volume and pore size distribution) of the chars are strongly dependent on water and nickel contents in the blends. One of the applications of Ni/C was demonstrated as a magnetically separable adsorbent.

  7. Synthesis, structural, optical and photocatalytic properties of CdS/ZnS core/shell nanoparticles

    Science.gov (United States)

    Reddy, Ch. Venkata; Shim, Jaesool; Cho, Migyung

    2017-04-01

    CdS, ZnS and CdS/ZnS core/shell nanoparticles were successfully synthesized via two-step synthesis method. The as-prepared CdS, ZnS and CdS/ZnS core/shell nanoparticles were used to study the structural, morphological, and optical properties by PXRD, TEM, HRTEM, UV-vis spectroscopy, N2 adsorption-desorption, FT-IR, PL and Raman spectroscopy measurements. The XRD pattern confirms the crystal structure of the prepared ZnS, CdS, and CdS/ZnS core/shell nanoparticles. The crystallinity of the as-prepared samples is confirmed by PXRD, TEM and HRTEM analysis. The BET analysis showed that the CdS/ZnS core/shell nanoparticles had larger surface area and pore diameter than CdS and ZnS. The Raman and FT-IR spectra confirm the fundamental vibrational modes of CdS and ZnS respectively. Compared to pure CdS and ZnS, CdS/ZnS core/shell nanoparticles exhibited higher photocatalytic activity for the degradation of methyl orange (MO). The enhancement of photocatalytic activity in the CdS/ZnS core/shell nanoparticles is due to the interface actions between CdS and ZnS, which greatly reduces the recombination of photogenerated electrons-holes pair. The proposed mechanism for degradation of MO dye is discussed in detail.

  8. New Diethyl Ammonium Salt of Thiobarbituric Acid Derivative: Synthesis, Molecular Structure Investigations and Docking Studies

    Directory of Open Access Journals (Sweden)

    Assem Barakat

    2015-11-01

    Full Text Available The synthesis of the new diethyl ammonium salt of diethylammonium(E-5-(1,5-bis(4-fluorophenyl-3-oxopent-4-en-1-yl-1,3-diethyl-4,6-dioxo-2-thioxohexaydropyrimidin-5-ide 3 via a regioselective Michael addition of N,N-diethylthiobarbituric acid 1 to dienone 2 is described. In 3, the carboanion of the thiobarbituric moiety is stabilized by the strong intramolecular electron delocalization with the adjacent carbonyl groups and so the reaction proceeds without any cyclization. The molecular structure investigations of 3 were determined by single-crystal X-ray diffraction as well as DFT computations. The theoretically calculated (DFT/B3LYP geometry agrees well with the crystallographic data. The effect of fluorine replacement by chlorine atoms on the molecular structure aspects were investigated using DFT methods. Calculated electronic spectra showed a bathochromic shift of the π-π* transition when fluorine is replaced by chlorine. Charge decomposition analyses were performed to study possible interaction between the different fragments in the studied systems. Molecular docking simulations examining the inhibitory nature of the compound show an anti-diabetic activity with Pa (probability of activity value of 0.229.

  9. Synthesis, structural and magnetic characterization of soft magnetic nanocrystalline ternary FeNiCo particles

    Energy Technology Data Exchange (ETDEWEB)

    Toparli, Cigdem [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey); Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf (Germany); Ebin, Burçak [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey); Nuclear Chemistry and Industrial Material Recycling, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, S-412 96 Gothenburg (Sweden); Gürmen, Sebahattin, E-mail: gurmen@itu.edu.tr [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey)

    2017-02-01

    The present study focuses on the synthesis, microstructural and magnetic properties of ternary FeNiCo nanoparticles. Nanocrystalline ternary FeNiCo particles were synthesized via hydrogen reduction assisted ultrasonic spray pyrolysis method in single step. The effect of precursor concentration on the morphology and the size of particles was investigated. The syntheses were performed at 800 °C. Structure, morphology and magnetic properties of the as-prepared products were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) studies. Scherer calculation revealed that crystallite size of the ternary particles ranged between 36 and 60 nm. SEM and TEM investigations showed that the particle size was strongly influenced by the precursor concentration and Fe, Ni, Co elemental composition of individual particles was homogeneous. Finally, the soft magnetic properties of the particles were observed to be a function of their size. - Highlights: • Ternary FeNiCo alloy nanocrystalline particles were synthesized in a single step. • Cubic crystalline structure and spherical morphology was observed by XRD, SEM and TEM investigations. • The analysis of magnetic properties indicates the soft magnetic features of particles.

  10. Structure determination of bisacetylenic oxylipins in carrots (Daucus carota L.) and enantioselective synthesis of falcarindiol.

    Science.gov (United States)

    Schmiech, Ludger; Alayrac, Carole; Witulski, Bernhard; Hofmann, Thomas

    2009-11-25

    Although bisacetylenic oxylipins have been demonstrated to exhibit diverse biological activities, the chemical structures of many representatives of this class of phytochemicals still remain elusive. As carrots play an important role in our daily diet and are known as a source of bisacetylenes, an extract made from Daucus carota L. was screened for bisacetylenic oxylipins, and, after isolation, their structures were determined by means of LC-MS and 1D/2D NMR spectroscopy. Besides the previously reported falcarinol, falcarindiol, and falcarindiol 3-acetate, nine additional bisacetylenes were identified, among which six derivatives are reported for the first time in literature and three compounds were previously not identified in carrots. To determine the absolute stereochemistry of falcarindiol in carrots, the (3R,8R)-, (3R,8S)-, (3S,8R)-, and (3S,8S)-stereoisomers of falcarindiol were synthesized according to a novel 10-step total synthesis involving a Cadiot-Chodkiewicz cross-coupling reaction of (S)- and (R)-trimethylsilanyl-4-dodecen-1-yn-3-ol and (R)- and (S)-5-bromo-1-penten-4-yn-3-ol, respectively. Comparative chiral HPLC analysis of the synthetic stereoisomers with the isolated phytochemical led to the unequivocal assignment of the (Z)-(3R,8S)-configuration for falcarindiol in carrot extracts from Daucus carota L.

  11. Chemical synthesis, 3D structure, and ASIC binding site of the toxin mambalgin-2.

    Science.gov (United States)

    Schroeder, Christina I; Rash, Lachlan D; Vila-Farrés, Xavier; Rosengren, K Johan; Mobli, Mehdi; King, Glenn F; Alewood, Paul F; Craik, David J; Durek, Thomas

    2014-01-20

    Mambalgins are a novel class of snake venom components that exert potent analgesic effects mediated through the inhibition of acid-sensing ion channels (ASICs). The 57-residue polypeptide mambalgin-2 (Ma-2) was synthesized by using a combination of solid-phase peptide synthesis and native chemical ligation. The structure of the synthetic toxin, determined using homonuclear NMR, revealed an unusual three-finger toxin fold reminiscent of functionally unrelated snake toxins. Electrophysiological analysis of Ma-2 on wild-type and mutant ASIC1a receptors allowed us to identify α-helix 5, which borders on the functionally critical acidic pocket of the channel, as a major part of the Ma-2 binding site. This region is also crucial for the interaction of ASIC1a with the spider toxin PcTx1, thus suggesting that the binding sites for these toxins substantially overlap. This work lays the foundation for structure-activity relationship (SAR) studies and further development of this promising analgesic peptide. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Thermoelectric plastics: from design to synthesis, processing and structure-property relationships.

    Science.gov (United States)

    Kroon, Renee; Mengistie, Desalegn Alemu; Kiefer, David; Hynynen, Jonna; Ryan, Jason D; Yu, Liyang; Müller, Christian

    2016-11-07

    Thermoelectric plastics are a class of polymer-based materials that combine the ability to directly convert heat to electricity, and vice versa, with ease of processing. Potential applications include waste heat recovery, spot cooling and miniature power sources for autonomous electronics. Recent progress has led to surging interest in organic thermoelectrics. This tutorial review discusses the current trends in the field with regard to the four main building blocks of thermoelectric plastics: (1) organic semiconductors and in particular conjugated polymers, (2) dopants and counterions, (3) insulating polymers, and (4) conductive fillers. The design and synthesis of conjugated polymers that promise to show good thermoelectric properties are explored, followed by an overview of relevant structure-property relationships. Doping of conjugated polymers is discussed and its interplay with processing as well as structure formation is elucidated. The use of insulating polymers as binders or matrices is proposed, which permit the adjustment of the rheological and mechanical properties of a thermoelectric plastic. Then, nanocomposites of conductive fillers such as carbon nanotubes, graphene and inorganic nanowires in a polymer matrix are introduced. A case study examines poly(3,4-ethylenedioxythiophene) (PEDOT) based materials, which up to now have shown the most promising thermoelectric performance. Finally, a discussion of the advantages provided by bulk architectures e.g. for wearable applications highlights the unique advantages that thermoelectric plastics promise to offer.

  13. Strontium substituted hydroxyapatites: Synthesis and determination of their structural properties, in vitro and in vivo performance

    Energy Technology Data Exchange (ETDEWEB)

    Kaygili, Omer, E-mail: okaygili@firat.edu.tr [Department of Physics, Faculty of Science, Firat University, 23119 Elazig (Turkey); Keser, Serhat [Department of Chemistry, Faculty of Science, Firat University, 23119 Elazig (Turkey); Kom, Mustafa [Department of Surgery, Faculty of Veterinary Medicine, Firat University, 23119 Elazig (Turkey); Eroksuz, Yesari [Department of Pathology, Faculty of Veterinary Medicine, Firat University, 23119 Elazig (Turkey); Dorozhkin, Sergey V. [Kudrinskaja square 1-155, Moscow 123242 (Russian Federation); Ates, Tankut [Department of Physics, Faculty of Science, Firat University, 23119 Elazig (Turkey); Ozercan, Ibrahim H. [Department of Pathology, School of Medicine, Firat University, 23119 Elazig (Turkey); Tatar, Cengiz; Yakuphanoglu, Fahrettin [Department of Physics, Faculty of Science, Firat University, 23119 Elazig (Turkey)

    2015-10-01

    The objective of this study is to present a detailed report related to the synthesis and characterization of strontium substituted hydroxyapatites. Based on this purpose, hydroxyapatite (HAp) bioceramics with different amounts of strontium (e.g., 0, 0.45, 0.90, 1.35, 1.80 and 2.25 at.%) were prepared using a sol–gel method. The effects of Sr substitution on the structural properties and biocompatibility of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques, in vitro and in vivo tests. All the samples composed of the nanoparticles ranging from 21 to 27 nm. The presence of Sr at low levels influenced the crystal size, crystallinity degree, lattice parameters and volume of the unit cell of the HAp. Both in vitro conditions and soaking period in simulated body fluid (SBF) significantly affected these properties. Especially, the (Ca + Sr)/P molar ratio gradually decreases with increasing soaking period in SBF. Animal experiments revealed the bone formation and osseointegration for all samples, and as compared with other groups, more reasonable, were observed for the sample with the lowest Sr content. - Highlights: • Sr content affects the structural properties of hydroxyapatite. • Bone formation and osseointegration are observed for all the samples. • In vitro conditions cause a significant change in the (Ca + Sr)/P ratio.

  14. Effect of synthesis methods and a comparative study of structural and magnetic properties of zinc ferrite

    Directory of Open Access Journals (Sweden)

    Md. Sazzad Hossain

    2017-10-01

    Full Text Available Zinc ferrite samples were prepared by two different routes which are chemical co-precipitation and standard solid state double sintering method. Structural properties of ZnFe2O4 were determined, and initial particle size was found as 5 nm in the samples prepared by chemical co-precipitation technique. The XRD patterns showed the single phase of ZnFe2O4 spinel structure and confirmed by the lattice parameter and the unmixed hkl values for both the synthesis techniques. M-H curves at room temperature showed superparamagnetic nature of the samples sintered from 200°C to 600°C, synthesized by chemical co-precipitation technique. The Mössbauer analysis at room temperature showed a doublet which is the signature of superparamagnetic nature, and it is in agreement with the acquired M-H curves. The magnetization of ZnFe2O4 synthesized by chemical co-precipitation method was found higher than the magnetization of ZnFe2O4 synthesized by the solid-state double sintering method in the sintering temperature from 1100°C to 1300°C.

  15. Synthesis, Optical and Structural Properties of Copper Sulfide Nanocrystals from Single Molecule Precursors

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    2017-02-01

    Full Text Available We report the synthesis and structural studies of copper sulfide nanocrystals from copper (II dithiocarbamate single molecule precursors. The precursors were thermolysed in hexadecylamine (HDA to prepare HDA-capped CuS nanocrystals. The optical properties of the nanocrystals studied using UV–visible and photoluminescence spectroscopy showed absorption band edges at 287 nm that are blue shifted, and the photoluminescence spectra show emission curves that are red-shifted with respect to the absorption band edges. These shifts are as a result of the small crystallite sizes of the nanoparticles leading to quantum size effects. The structural studies were carried out using powder X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS, and atomic force microscopy. The XRD patterns indicates that the CuS nanocrystals are in hexagonal covellite crystalline phases with estimated particles sizes of 17.3–18.6 nm. The TEM images showed particles with almost spherical or rod shapes, with average crystallite sizes of 3–9.8 nm. SEM images showed morphology with ball-like microspheres on the surfaces, and EDS spectra confirmed the presence of CuS nanoparticles.

  16. Synthesis of 2-monoacylglycerols and structured triacylglycerols rich in polyunsaturated fatty acids by enzyme catalyzed reactions.

    Science.gov (United States)

    Rodríguez, Alicia; Esteban, Luis; Martín, Lorena; Jiménez, María José; Hita, Estrella; Castillo, Beatriz; González, Pedro A; Robles, Alfonso

    2012-08-10

    This paper studies the synthesis of structured triacylglycerols (STAGs) by a four-step process: (i) obtaining 2-monoacylglycerols (2-MAGs) by alcoholysis of cod liver oil with several alcohols, catalyzed by lipases Novozym 435, from Candida antartica and DF, from Rhizopus oryzae, (ii) purification of 2-MAGs, (iii) formation of STAGs by esterification of 2-MAGs with caprylic acid catalyzed by lipase DF, from R. oryzae, and (iv) purification of these STAGs. For the alcoholysis of cod liver oil, absolute ethanol, ethanol 96% (v/v) and 1-butanol were compared; the conditions with ethanol 96% were then optimized and 2-MAG yields of around 54-57% were attained using Novozym 435. In these 2-MAGs, DHA accounted for 24-31% of total fatty acids. In the operational conditions this lipase maintained a stable level of activity over at least 11 uses. These results were compared with those obtained with lipase DF, which deactivated after only three uses. The alcoholysis of cod liver oil and ethanol 96% catalyzed by Novozym 435 was scaled up by multiplying the reactant amounts 100-fold and maintaining the intensity of treatment constant (IOT=3g lipase h/g oil). In these conditions, the 2-MAG yield attained was about 67%; these 2-MAGs contained 36.6% DHA. The synthesized 2-MAGs were separated and purified from the alcoholysis reaction products by solvent extraction using solvents of low toxicity (ethanol and hexane); 2-MAG recovery yield and purity of the target product were approximately 96.4% and 83.9%, respectively. These 2-MAGs were transformed to STAGs using the optimal conditions obtained in a previous work. After synthesis and purification, 93% pure STAGs were obtained, containing 38% DHA at sn-2 position and 60% caprylic acid (CA) at sn-1,3 positions (of total fatty acids at these positions), i.e. the major TAG is the STAG with the structure CA-DHA-CA. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Synthesis and structural evaluation of five coordination complexes of benzenepentacarboxylic acid with aza-donor ligands

    Science.gov (United States)

    Shimpi, Manishkumar R.; Biswas, Sharmita Nandy; Sarkar, Sohini; Pedireddi, V. R.

    2016-06-01

    Synthesis and structural features of five new coordination assemblies, [Co(bpyH)(H2O)5](BPCH)·(bpyH2)0.5·(H2O) (1a), [{Cu(H2O)3}·{Cu0.5(bpy)0.5(H2O)0.5}2(μ-BPCH)] (1b), [{Cd0.5(BPCH)}2·{Cd0.5(bpy)(H2O)2}2]·6(H2O) (1c), [Cu(BPCH2)(bpyeaH)]·2(H2O) (1d) and [Cd2 (bpyea)0.5(oxalate)0.5(μ-BPC) (H2O)]·(bpyeaH2)·2(H2O) (1e), have been reported. All the assemblies were prepared by co-crystallization of benzenepentacarboxylic acid (BPCH5) either with 4,4‧-bipyridine (bpy) or 1,2-bis(4-pyridyl)ethane (bpyea) in the presence of a transition metal ion (either Co(II), Cu(II) or Cd(II)) as the case may be. All the five compounds were synthesized by hydrothermal method and structures were determined by single crystal X-ray diffraction. All the obtained compounds, 1a-1e, exhibit distinct 3-D polymeric architectures either in the form of stacked layers or host-guest networks in which water molecules play a pivotal role providing additional stabilization by coordinate bonds as well as hydrogen bonds. Other non-covalent interactions such as C-H … π and π … π stacking also participate in the formation of exotic 3-D structures of these complexes.

  18. Novel synthesis and structural analysis of zinc oxide nanoparticles for the non enzymatic glucose biosensor.

    Science.gov (United States)

    Dayakar, T; Venkateswara Rao, K; Bikshalu, K; Rajendar, V; Park, Si-Hyun

    2017-06-01

    A non-enzymatic glucose biosensor was developed by utilizing the zinc oxide nanoparticles (ZnO NPs) synthesized by a novel green method using the leaf extract of Ocimum tenuiflorum. The structural, optical and morphological properties of ZnO NPs characterized by means of X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, and transmission electron microscopy (TEM). The XRD analysis revealed that the ZnO NPs were crystalline and had a hexagonal wurtzite structure. The crystallite size measured by XRD was the same as that measured using SEM and TEM. The UV-vis absorption spectrum estimates the band gap of ZnO NPs present in the range of 2.82 to 3.45eV. The reduction and formation of ZnO NPs mainly due to the involvement of leaf extract bio-molecular compounds analyzed from the FTIR spectra. The SEM result confirms the morphology of the NPs responsible from the various concentration of leaf extract in the synthesis process. HRTEM analysis depicts the spherical structure of ZnO NPs. The synthesized NPs have the average size ranges from 10 to 20nm. The fabricated GCE/ZnO glucose sensor represents superior electro catalytic activity that has been observed for ZnO NPs with a reproducible sensitivity of 631.30μAmM -1 cm -2 , correlation coefficient of R=0.998, linear dynamic range from 1-8.6mM, low detection limit of 0.043μM (S/N=3) and response time<4s. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Synthesis, structural, DFT studies, docking and antibacterial activity of a xanthene based hydrazone ligand

    Science.gov (United States)

    Naseem, Saira; Khalid, Muhammad; Tahir, Muhammad Nawaz; Halim, Mohammad A.; Braga, Ataualpa A. C.; Naseer, Muhammad Moazzam; Shafiq, Zahid

    2017-09-01

    Herein, we present the synthesis of novel xanthene-based hydrazone (1). The chemical structure of 1 was resolved using spectroscopic techniques such as NMR, FT-IR, UV-VIS and X-ray crystallographic approaches. X-ray diffraction analysis shows that the compound (1) crystallizes in triclinic crystal lattice with the Pbar1 space group and diffused to form multi-layered structure due to non-covalent interactions such as intramolecular hydrogen bonding (H.B). In addition to experimental investigation, density functional theory (DFT) calculation with M06-2X/6-31G(d,p) and B3LYP/6-31G(d,p) level of theories was performed on compound (1) to obtain optimized geometry, spectroscopic and electronic properties. DFT optimized geometry shows good agreement with the experimental XRD structure. The hyper conjugative interactions and hydrogen bonding network are responsible for the stability of compound (1) as revealed by natural bond orbital (NBO) calculation. Moreover, hydrogen bonding network in the dimer is confirmed by FT-IR and thermodynamic studies showing excellent agreement with XRD and NBO findings. TD-DFT/UV-VIS analysis provides insight that maximum excitation is found in 1 which shows good agreement with experimental UV-VIS result. The global reactivity parameters are calculated using the energies of frontier molecular orbitals also disclosed that the compound is more stable might be due to hydrogen bonding network. Experimental and molecular docking studies indicated that this compound has anti-bacterial and anti-diabetic properties. The binding affinity of this compound against the multidrug efflux pump subunit AcrB OS=Escherichia coli (strain K12) and Human Pancreatic Alpha-Amylase is -9.2 and -10.00 kcal/mol which are higher than the control drugs. Pi-Pi, Pi-anaion, amide-pi and pi-alkyl bonds play key role in drug-protein complexes.

  20. Vascular wall proteoglycan synthesis and structure as a target for the prevention of atherosclerosis

    Directory of Open Access Journals (Sweden)

    Peter J Little

    2007-03-01

    Full Text Available Peter J Little1, 2, 3, Mandy L. Ballinger1, Narin Osman1,31Cell Biology of Diabetes Laboratory, Baker Heart Research Institute, Melbourne, Australia; Monash University, Departments of 2Medicine and 3Immunology, Central and Eastern Clinical School, Alfred Hospital, Melbourne, AustraliaAbstract: Atherosclerosis is the underlying pathology of most cardiovascular disease and it represents the major cause of premature death in modern societies. Current therapies target risk factors being hypertension, hypercholesterolemia, hypertriglyceridemia and hyperglycemia when diabetes is present however the maximum efficacy of these strategies is often 30% or less. Areas of vascular biology that may lead to the development of a complementary vascular wall directed therapy are: inflammation, oxidation, endothelial dysfunction, diabetes-specific factors —hyperglycemia and advanced glycation endproducts and lipid retention by vascular matrix specifically proteoglycans. The major structural features of proteoglycans that determine low-density lipoprotein (LDL binding are the length and sulfation pattern on the glycosaminoglycan (GAG chains. Emerging data discussed in this review indicates that these structural properties are subject to considerable regulation by vasoactive substances possibly using novel signaling pathways. For example, GAG elongation stimulated by platelet-derived growth factor is not blocked by the receptor tyrosine kinase antagonist, genistein suggesting that there may be a previously unknown signaling pathway involved in this response. Thus, modifying proteoglycan synthesis and structure may represent a prime target to prevent LDL binding and entrapment in the vessel wall and thus prevent the development and progression of atherosclerosis.Keywords: proteoglycans, signaling, lipoproteins, atherosclerosis

  1. A Better Understanding of Protein Structure and Function by the Synthesis and Incorporation of Selenium- and Tellurium Containing Tryptophan Analogs

    Energy Technology Data Exchange (ETDEWEB)

    Helmey, Sherif Samir [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Belmont Univ., Nashville, TN (United States). Dept. of Chemistry and Physics; Rice, Ambrose Eugene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Belmont Univ., Nashville, TN (United States). Dept. of Chemistry and Physics; Hatch, Duane Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Belmont Univ., Nashville, TN (United States). Dept. of Chemistry and Physics; Silks, Louis A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division; Marti-Arbona, Ricardo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Bioscience Division

    2016-08-17

    Unnatural heavy metal-containing amino acid analogs have shown to be very important in the analysis of protein structure, using methods such as X-ray crystallography, mass spectroscopy, and NMR spectroscopy. Synthesis and incorporation of selenium-containing methionine analogs has already been shown in the literature however with some drawbacks due to toxicity to host organisms. Thus synthesis of heavy metal tryptophan analogs should prove to be more effective since the amino acid tryptophan is naturally less abundant in many proteins. For example, bioincorporation of β-seleno[3,2-b]pyrrolyl-L-alanine ([4,5]SeTrp) and β-selenolo[2,3-b]pyrrolyl-L-alanine ([6,7]SeTrp) has been shown in the following proteins without structural or catalytic perturbations: human annexin V, barstar, and dihydrofolate reductase. The reported synthesis of these Se-containing analogs is currently not efficient for commercial purposes. Thus a more efficient, concise, high-yield synthesis of selenotryptophan, as well as the corresponding, tellurotryptophan, will be necessary for wide spread use of these unnatural amino acid analogs. This research will highlight our progress towards a synthetic route of both [6,7]SeTrp and [6,7]TeTrp, which ultimately will be used to study the effect on the catalytic activity of Lignin Peroxidase (LiP).

  2. Microwave-assisted hydrothermal synthesis of CePO4 nanostructures: Correlation between the structural and optical properties

    International Nuclear Information System (INIS)

    Palma-Ramírez, D.; Domínguez-Crespo, M.A.; Torres-Huerta, A.M.; Dorantes-Rosales, H.; Ramírez-Meneses, E.; Rodríguez, E.

    2015-01-01

    Highlights: • An enhancement in the hydrothermal synthesis for obtaining of CePO 4 is presented. • Microwave energy can replace the energy by convection for obtaining CePO 4 . • CePO 4 demonstrates to be an option to increase the optical properties of polymers. • Adjusting the pH, the sintering process is not necessary to obtain the desire phase. • CePO 4 morphologies undergo evolution from nanorods to semispherical nanoparticles. - Abstract: In this work, the microwave-assisted hydrothermal method is proposed as an alternative to the synthesis of cerium phosphate (CePO 4 ) nanostructures to evaluate the influence of different synthesis parameters on both the structural and optical properties. In order to reach this goal, two different sets of experiments were designed, varying the reaction temperature (130 and 180 °C), synthesis time (15 and 30 min) and sintering temperature (400 and 600 °C), maintaining a constant pH = 3. Thereafter, two experimental conditions were selected to assess changes in the properties of CePO 4 nanopowders with pH (1, 5, 9 and 11). The crystal structure and morphology of the nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Diffuse reflectance properties of CePO 4 with different microstructures were studied. The results demonstrated that by using the microwave-assisted hydrothermal method, the shape, size and structural phase of CePO 4 can be modulated by using relatively low synthesis temperatures and short reaction times, and depending on pH, a sintering process is not needed to obtain either a desired phase or size. Under the selected experimental conditions, the materials underwent an evolution from nanorods to semispherical nanoparticles, accompanied by a phase transition from hexagonal to monoclinic

  3. Microwave-assisted hydrothermal synthesis of CePO{sub 4} nanostructures: Correlation between the structural and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Palma-Ramírez, D. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Domínguez-Crespo, M.A., E-mail: mdominguezc@ipn.mx [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Torres-Huerta, A.M. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Dorantes-Rosales, H. [Instituto Politécnico Nacional, ESIQIE, Departamento de Metalurgia, C.P. 07300 México D.F. (Mexico); Ramírez-Meneses, E. [Universidad Iberoamericana, Departamento de Ingeniería y Ciencias Químicas, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, C.P. 01219 México D.F. (Mexico); Rodríguez, E. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico)

    2015-09-15

    Highlights: • An enhancement in the hydrothermal synthesis for obtaining of CePO{sub 4} is presented. • Microwave energy can replace the energy by convection for obtaining CePO{sub 4}. • CePO{sub 4} demonstrates to be an option to increase the optical properties of polymers. • Adjusting the pH, the sintering process is not necessary to obtain the desire phase. • CePO{sub 4} morphologies undergo evolution from nanorods to semispherical nanoparticles. - Abstract: In this work, the microwave-assisted hydrothermal method is proposed as an alternative to the synthesis of cerium phosphate (CePO{sub 4}) nanostructures to evaluate the influence of different synthesis parameters on both the structural and optical properties. In order to reach this goal, two different sets of experiments were designed, varying the reaction temperature (130 and 180 °C), synthesis time (15 and 30 min) and sintering temperature (400 and 600 °C), maintaining a constant pH = 3. Thereafter, two experimental conditions were selected to assess changes in the properties of CePO{sub 4} nanopowders with pH (1, 5, 9 and 11). The crystal structure and morphology of the nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Diffuse reflectance properties of CePO{sub 4} with different microstructures were studied. The results demonstrated that by using the microwave-assisted hydrothermal method, the shape, size and structural phase of CePO{sub 4} can be modulated by using relatively low synthesis temperatures and short reaction times, and depending on pH, a sintering process is not needed to obtain either a desired phase or size. Under the selected experimental conditions, the materials underwent an evolution from nanorods to semispherical nanoparticles, accompanied by a phase transition from hexagonal to monoclinic.

  4. On the synthesis of vanadium containing molecular sieves by experimental design from a VOSO4.5H2O.Al(iPrO)3.Pr2NH.H2O gel: occurrence of VAPO-41 as a secondary structure in the synthesis of VAPO-11

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Frunza, L.; Voort, P. van der; Vansant, E.F.; Schoonheydt, R.A.

    2000-01-01

    An experimental design was applied to the hydrothermal synthesis of VAPO-11 molecular sieve (AEL structure)from a VOSO4.5H2O.Al(iPrO)3.Pr2NH.H2O gel. The influence of five synthesis parameters (synthesis temperature, synthesis time, vanadium content, water content and template content) on the

  5. Titanium Dioxide Nanoparticles: Synthesis, X-Ray Line Analysis and Chemical Composition Study

    OpenAIRE

    Chenari,Hossein Mahmoudi; Seibel,Christoph; Hauschild,Dirk; Reinert,Friedrich; Abdollahian,Hossein

    2016-01-01

    TiO$_{2}$ nanoparticleshave been synthesized by the sol-gel method using titanium alkoxide and isopropanolas a precursor. The structural properties and chemical composition of the TiO$_{2}$ nanoparticles were studied usingX-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy.The X-ray powder diffraction pattern confirms that the particles are mainly composed of the anatase phase with the preferential orientation along [101] direction.The physical parameters suc...

  6. Controlled synthesis and structure characterization of nanostructured MnWO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Hu, W.B., E-mail: w.hu@tom.com [Hubei Institute for Nationalities, Enshi 445000 (China); Nie, X.L.; Mi, Y.Zh. [Hubei Institute for Nationalities, Enshi 445000 (China)

    2010-01-15

    Using Mn to partly substitute the W in W{sub 18}O{sub 49} nanowires, the synthesis of MnWO{sub 4} hubnerite nano-cocoons is described in this paper, by using mixed MnCl{sub 2} and WCl{sub 6} as the precursors and cyclohexanol as the solvent, in a simple solvothermal process. Detailed characterization of the resulting products, using electron microscopy and spectroscopy, has shown that the gradual increase of MnCl{sub 2} concentration changes the long W{sub 18}O{sub 49} nanowires to cocoon-like nanomaterials of stable MnWO{sub 4} phase. The driving force for such transformations is attributed to the Mn{sup 2+} inclusion within the W{sub 18}O{sub 49}. At low Mn{sup 2+} concentration, internal stresses would be introduced to the W{sub 18}O{sub 49} nanowires; whilst at high Mn{sup 2+} concentration close to the stoichiometric composition of MnWO{sub 4}, the formation of the nano-cocoons is triggered by the intrinsic crystalline feature of the hubnerite. It is believed that a combination of the initial nanowire nucleation and competing growth, and of self-assembly of neighboring parallel nanowires, leads to the final structure.

  7. Controlled synthesis and structure characterization of nanostructured MnWO4

    International Nuclear Information System (INIS)

    Hu, W.B.; Nie, X.L.; Mi, Y.Zh.

    2010-01-01

    Using Mn to partly substitute the W in W 18 O 49 nanowires, the synthesis of MnWO 4 hubnerite nano-cocoons is described in this paper, by using mixed MnCl 2 and WCl 6 as the precursors and cyclohexanol as the solvent, in a simple solvothermal process. Detailed characterization of the resulting products, using electron microscopy and spectroscopy, has shown that the gradual increase of MnCl 2 concentration changes the long W 18 O 49 nanowires to cocoon-like nanomaterials of stable MnWO 4 phase. The driving force for such transformations is attributed to the Mn 2+ inclusion within the W 18 O 49 . At low Mn 2+ concentration, internal stresses would be introduced to the W 18 O 49 nanowires; whilst at high Mn 2+ concentration close to the stoichiometric composition of MnWO 4 , the formation of the nano-cocoons is triggered by the intrinsic crystalline feature of the hubnerite. It is believed that a combination of the initial nanowire nucleation and competing growth, and of self-assembly of neighboring parallel nanowires, leads to the final structure.

  8. Influence of the synthesis conditions of gold nanoparticles on the structure and architectonics of dipeptide composites

    Energy Technology Data Exchange (ETDEWEB)

    Loskutov, Alexander I., E-mail: ailoskutov@yandex.ru [Moscow State Technological University STANKIN (Russian Federation); Guskova, Olga A. [Leibniz Institute of Polymer Research Dresden (Germany); Grigoriev, Sergey N.; Oshurko, Vadim B. [Moscow State Technological University STANKIN (Russian Federation); Tarasiuk, Aleksei V. [Russian Academy of Medical Sciences, FSBI “Zakusov Institute of Pharmacology” (Russian Federation); Uryupina, Olga Ya. [Russian Academy of Sciences, Frumkin Institute of Physical Chemistry and Electrochemistry (Russian Federation)

    2016-08-15

    A wide variety of peptides and their natural ability to self-assemble makes them very promising candidates for the fabrication of solid-state devices based on nano- and mesocrystals. In this work, we demonstrate an approach to form peptide composite layers with gold nanoparticles through in situ reduction of chloroauric acid trihydrate by dipeptide and/or dipeptide/formaldehyde mixture in the presence of potassium carbonate at different ratios of components. Appropriate composition of components for the synthesis of highly stable gold colloidal dispersion with particle size of 34–36 nm in dipeptide/formaldehyde solution is formulated. Infrared spectroscopy results indicate that dipeptide participates in the reduction process, conjugation with gold nanoparticles and the self-assembly in 2D, which accompanied by changing peptide chain conformations. The structure and morphology of the peptide composite solid layers with gold nanoparticles on gold, mica and silica surfaces are characterized by atomic force microscopy. In these experiments, the flat particles, dendrites, chains, mesocrystals and Janus particles are observed depending on the solution composition and the substrate/interface used. The latter aspect is studied on the molecular level using computer simulations of individual peptide chains on gold, mica and silica surfaces.

  9. Synthesis of adsorbent with zeolite structure from red mud and rice husk ash and its properties

    Science.gov (United States)

    Quyen, Dinh Thi Ngoc; Loc, Luu Cam; Ha, Huynh Ky Phuong; Nga, Dang Thi Hang; Tri, Nguyen; Van, Nguyen Thi Thuy

    2017-09-01

    There are many researches in the modification of red mud as adsorbent for treatment of wastewater or waste gases. Yet, most of them have to face up with a thorny problem caused by remaining alkali in red mud. In this study, the material with zeolite structure was synthesized by fusion method using red mud with the remaining alkali and rice husk ash as raw materials. It comprised alkaline fusion followed by hydrothermal treatment with step - change of synthesis temperature. The synthesized materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET and CO2 adsorption capacity. The influences on the quality of these materialswere investigated under various calcination temperatures, calcination times and the ratios of raw materials (based on SiO2/Al2O3 ratio). The optimum reaction parameters were determined. The results depicted that the sample treated at 600 °C for 2 hours with the ratio of SiO2/Al2O3 of 1.8 had the best adsorption capacity and total specific surface area compared with the others.

  10. Solid-solid synthesis and structural phase transition process of SmF3

    Science.gov (United States)

    Yan, Qi-Cao; Guo, Xing-Min

    2018-04-01

    Mazes of contradictory conclusions have been obtained by previous researches about structural phase transition process of SmF3. In this paper, the single crystals of SmF3 (hexagonal and orthorhombic) were prepared by solid-solid synthesis, which have shown gradual changes in crystal growth modes with the increase temperature and holding time. Furthermore, we propose the phase transition process of in SmF3. Hexagonal symmetry of SmF3 (space group Pnma) was prepared firstly by heating Sm2O3 and NH4HF2 over 40 min at 270 °C. And then orthorhombic symmetry of SmF3 (space group P63mc) was obtained by heating hexagonal symmetry over 10 h at 650 °C. The reaction of SmF3 (hexagonal) = SmF3 (orthorhombic) is extremely sluggish at a low temperature (less than 650 °C), which was seen as a Mixed Grown Region.

  11. Synthesis, structure, and antiproliferative activity of selenophenfurin, an inosine 5'-monophosphate dehydrogenase inhibitor analogue of selenazofurin.

    Science.gov (United States)

    Franchetti, P; Cappellacci, L; Sheikha, G A; Jayaram, H N; Gurudutt, V V; Sint, T; Schneider, B P; Jones, W D; Goldstein, B M; Perra, G; De Montis, A; Loi, A G; La Colla, P; Grifantini, M

    1997-05-23

    The synthesis and biological activity of selenophenfurin (5-beta-D-ribofuranosylselenophene-3-carboxamide, 1), the selenophene analogue of selenazofurin, are described. Glycosylation of ethyl selenophene-3-carboxylate (6) under stannic chloride-catalyzed conditions gave 2- and 5-glycosylated regioisomers, as a mixture of alpha- and beta-anomers, and the beta-2,5-diglycosylated derivative. Deprotected ethyl 5-beta-D-ribofuranosylselenophene-3-carboxylate (12 beta) was converted into selenophenfurin by ammonolysis. The structure of 12 beta was determined by 1H- and 13C-NMR, crystallographic, and computational studies. Selenophenfurin proved to be antiproliferative against a number of leukemia, lymphoma, and solid tumor cell lines at concentrations similar to those of selenazofurin but was more potent than the thiophene and thiazole analogues thiophenfurin and tiazofurin. Incubation of K562 cells with selenophenfurin resulted in inhibition of IMP dehydrogenase (IMPDH) (76%) and an increase in IMP pools (14.5-fold) with a concurrent decrease in GTP levels (58%). The results obtained confirm the hypothesis that the presence of heteroatoms such as S or Se in the heterocycle in position 2 with respect to the glycosidic bond is essential for both cytotoxicity and IMP dehydrogenase inhibitory activity in this type of C-nucleosides.

  12. Synthesis, structural and spectroscopic studies of 2-oxoacenaphthylen-1(2H)-ylidene nicotinohydrazide.

    Science.gov (United States)

    Henriques, M S C; Del Amparo, R; Pérez-Álvarez, D; Nogueira, B A; Rodríguez-Argüelles, M C; Paixão, J A

    2017-02-05

    The synthesis of a new hydrazone, 2-oxoacenaphthylen-1(2H)-ylidene nicotinohydrazide, and its structural and spectroscopic characterization is reported. The obtained powder was recrystallized from DMSO and ethanol that afforded small crystals used for single-crystal X-ray diffraction studies. The compound was found to crystallize in two polymorphs, depending on the crystallization conditions. One of the polymorphs (form I) crystallizes in the centrosymmetric P2 1 /c monoclinic space group, the other (form II) crystallizes in the non-centrosymmetric, but achiral, orthorhombic space group P2 1 2 1 2 1 . Conformation of the molecules is similar in both polymorphs, but the network of weak intermolecular interactions determining the crystal packing is different. In form II an additional C-H⋯O bond connects molecules related by the screw-axis running parallel to the a-axis. Crystals of both polymorphs were also screened by FT-IR and Raman microscopy; a detailed analysis of the spectra and comparison with those of the isolated molecule calculated by ab-initio HF/MP2 and DFT/B3LYP methods using a correlation consistent cc-pVDZ basis set is presented. In addition, UV-vis and NMR studies were performed in solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Combustion synthesis by reaction and characterization of structural Ni-Zn ferrite doped with copper

    International Nuclear Information System (INIS)

    Dantas, J.; Santos, J.R.D.; Cunha, R.B.L.; Feitosa, C.A.; Costa, A.C.F.M.

    2012-01-01

    The present stud aims to evaluate the effect of doping with Cu 2+ ions concentrations of 0.0, 0.1, 0.2, 0.3 and 0.4 mol in the synthesis and structure of Ni-Zn ferrite. Samples were synthesized by the method of the combustion reaction and characterized by measuring the temperature as a function of reaction time, X-ray diffraction (XRD) and infrared spectroscopy in Fourier transform (FTIR). The combustion temperature and time were 646, 900, 989, 975 and 735°C and 210, 175, 220, 210 and 110 seconds for the sample doped with 0.0, 0.1, 0.2, 0.3 and 0.4 mol of copper, respectively. XRD results show that all concentrations of copper evaluated, there was only a training phase inverse spinel ferrite and Ni-Zn FTIR spectra show absorption bands below 1000cm -1 , which are characteristics of the spinel type AB 2 O 4- (author)

  14. Synthesis, effect of capping agents, structural, optical and photoluminescence properties of ZnO nanoparticles

    International Nuclear Information System (INIS)

    Singh, A.K.; Viswanath, V.; Janu, V.C.

    2009-01-01

    Zinc oxide nanoparticles were synthesized using chemical method in alcohol base. During synthesis three capping agents, i.e. triethanolamine (TEA), oleic acid and thioglycerol, were used and the effect of concentrations was analyzed for their effectiveness in limiting the particle growth. Thermal stability of ZnO nanoparticles prepared using TEA, oleic acid and thioglycerol capping agents, was studied using thermogravimetric analyzer (TGA). ZnO nanoparticles capped with TEA showed maximum weight loss. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for structural and morphological characterization of ZnO nanoparticles. Particle size was evaluated using effective mass approximation method from UV-vis spectroscopy and Scherrer's formula from XRD patterns. XRD analysis revealed single crystal ZnO nanoparticles of size 12-20 nm in case of TEA capping. TEA, oleic acid and thioglycerol capped synthesized ZnO nanoparticles were investigated at room temperature photoluminescence for three excitation wavelengths i.e. 304, 322 and 325 nm, showing strong peaks at about 471 nm when excited at 322 and 325 nm whereas strong peak was observed at 411 for 304 nm excitation.

  15. Nanoscale Hollow Spheres: Microemulsion-Based Synthesis, Structural Characterization and Container-Type Functionality

    Directory of Open Access Journals (Sweden)

    Marcus Roming

    2010-08-01

    Full Text Available A wide variety of nanoscale hollow spheres can be obtained via a microemulsion approach. This includes oxides (e.g., ZnO, TiO2, SnO2, AlO(OH, La(OH3, sulfides (e.g., Cu2S, CuS as well as elemental metals (e.g., Ag, Au. All hollow spheres are realized with outer diameters of 10-60 nm, an inner cavity size of 2-30 nm and a wall thickness of 2-15 nm. The microemulsion approach allows modification of the composition of the hollow spheres, fine-tuning their diameter and encapsulation of various ingredients inside the resulting “nanocontainers”. This review summarizes the experimental conditions of synthesis and compares them to other methods of preparing hollow spheres. Moreover, the structural characterization and selected properties of the as-prepared hollow spheres are discussed. The latter is especially focused on container-functionalities with the encapsulation of inorganic salts (e.g., KSCN, K2S2O8, KF, biomolecules/bioactive molecules (e.g., phenylalanine, quercetin, nicotinic acid and fluorescent dyes (e.g., rhodamine, riboflavin as representative examples.

  16. Synthesis, characterization, and structural analyses of two cyanide-bridged bimetallic complexes

    Science.gov (United States)

    Kautz, J. A.; Mullica, D. F.; Cunningham, B. P.; Combs, R. A.; Farmer, J. M.

    2000-05-01

    The crystal structures of two bimetallic cyanide-bridged lanthanide (Ln) complexes were obtained by means of three-dimensional single-crystal X-ray diffraction techniques. The isostructural complexes (DMF)4(H2O)3LaFe(CN)6·H2O (I) and (DMF)4(H2O)3CeFe(CN)6·H2O (II) crystallize in the monoclinic system with Z=4 having respective lattice constants of a=17.660(2), 17.633(4); b=8.952(1), 8.920(2); c=20.017(2), 19.950(4) Å; and β=95.68(1), 95.72(3). In each complex, the coordination about the central lanthanide ion is eight in a square antiprism arrangement while the coordination about the iron(III) ion is six, oriented octahedrally. Molecules in the crystal lattice of each complex are held together by normal van der Waals forces and a network of hydrogen bonding. Characterization includes physical property determinations, conoscopic studies, thermal gravimetric analyses (TGA), and IR spectrometric identifications. Select geometric parameters are tabulated and a synthesis of these compounds is presented.

  17. Synthesis, photodynamic activity, and quantitative structure-activity relationship modelling of a series of BODIPYs.

    Science.gov (United States)

    Caruso, Enrico; Gariboldi, Marzia; Sangion, Alessandro; Gramatica, Paola; Banfi, Stefano

    2017-02-01

    Here we report the synthesis of eleven new BODIPYs (14-24) characterized by the presence of an aromatic ring on the 8 (meso) position and of iodine atoms on the pyrrolic 2,6 positions. These molecules, together with twelve BODIPYs already reported by us (1-12), represent a large panel of BODIPYs showing different atoms or groups as substituent of the aromatic moiety. Two physico-chemical features ( 1 O 2 generation rate and lipophilicity), which can play a fundamental role in the outcome as photosensitizers, have been studied. The in vitro photo-induced cell-killing efficacy of 23 PSs was studied on the SKOV3 cell line treating the cells for 24h in the dark then irradiating for 2h with a green LED device (fluence 25.2J/cm 2 ). The cell-killing efficacy was assessed with the MTT test and compared with that one of meso un-substituted compound (13). In order to understand the possible effect of the substituents, a predictive quantitative structure-activity relationship (QSAR) regression model, based on theoretical holistic molecular descriptors, was developed. The results clearly indicate that the presence of an aromatic ring is fundamental for an excellent photodynamic response, whereas the electronic effects and the position of the substituents on the aromatic ring do not influence the photodynamic efficacy. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Hydrothermal synthesis of zeolite T from kaolin using two different structure-directing agents

    Science.gov (United States)

    Arshad, Sazmal E.; Lutfor Rahman, M.; Sarkar, Shaheen M.; Yusslee, Eddy F.; Patuwan, Siti Z.

    2018-01-01

    Zeolite T was synthesized from the molar chemical composition of 1SiO2:0.04Al2O3:0.26Na2O:0.09K2O:14H2O in the form of a homogenous milky solution in the presence of the two different structure-directing agents TMAOH and TEAOH respectively. Modification of the composition of silica was undertaken using metakaolin from calcined kaolin at 750 °C for 4 h, while the molar composition of each different SDA was variated from 0.05, 0.10, 0.15, 0.20 and 0.25. The homogenous mixture was left at room temperature for 24 h before undergoing hydrothermal synthesis at 100 °C for 168 h. The synthesized samples were filtered and aged at 120 °C for 2 h and each sample was calcined at high temperatures (545 °C for TMAOH and 520 °C for TEAOH) for template removal before characterization using XRD and SEM. Crystallization of the zeolite T in its major form only took place at a molar ratio of 0.10 of TMAOH, while TEAOH showed the species evolution of zeolite T into zeolite L and W for other molar ratios.

  19. Synthesis and crystal structures of gold nanowires with Gemini surfactants as directing agents.

    Science.gov (United States)

    Xu, Feng; Hou, Hao; Gao, Zhinong

    2014-12-15

    The preparation of crystalline gold nanowires (NWs) by using gemini surfactants as directing agents through a three-step seed-mediated method is reported. Unlike the nanorods with relatively low aspect ratios (typically below 20) obtained by using cetyltrimethylammonium bromide as a directing agent, the NWs obtained in this investigation can reach up to 4.4 μm, and the largest aspect ratio is calculated to be 210. For this, each of seven different gemini surfactants are utilized as directing agents, and the length and/or aspect ratio of the NWs can be tuned by varying the hydrocarbon chain lengths of the gemini surfactants. Both single and twinned crystalline structures are elucidated by selected-area electron diffraction and high-resolution transmission electron microscopy studies. The use of gemini surfactants not only advances the synthesis of gold nanostructures, but improves the understanding of the growth mechanism for seed-mediated growth. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Synthesis, Crystal Structure and in vitro DNA Binding Studies of Combretastatin A-4 Analogue

    Directory of Open Access Journals (Sweden)

    Masood Ahmad Rizvi

    2015-12-01

    Full Text Available Synthesis of a novel Combretastatin A-4 analogue using Schiff’s reaction of benzil and 4-aminoantipyrine has been achieved under solvent free conditions. The structure of compound was examined spectroscopically and confirmed from single crystal diffraction studies. The synthesized Combretastatin A-4 analogue was investigated for its DNA binding ability as the plausible mechanism for its antitumor activity. The binding propensity of the synthesized compound with calf-thymus (CT DNA was monitored with absorption and emission spectrophotometric titrations. The calculations predict a binding constant of 7.24×104 for the complex of the synthesized compound with CT DNA which is comparable in magnitude to that of DNA binding of bactericidal drug enoxacin and typical intercalation indicator ethidium bromide (EB. Competitive binding studies of the synthesized compound with EB using fluorescence titration reveal that it displaces the DNA-bound EB and binds in intercalative mode which was further supported by circular dichroism (CD spectroscopy. The probable site and binding energy of the compound with DNA was further theoretically investigated by molecular docking studies. The significant DNA binding ability of the synthesized Combretastatin A4 analogue as revealed from this study could be related to the anticancer activity of the Combretastatin A4.

  1. Synthesis, Molecular Structure and Spectroscopic Investigations of Novel Fluorinated Spiro Heterocycles

    Directory of Open Access Journals (Sweden)

    Mohammad Shahidul Islam

    2015-05-01

    Full Text Available This paper describes an efficient and regioselective method for the synthesis of novel fluorinated spiro-heterocycles in excellent yield by cascade [5+1] double Michael addition reactions. The compounds 7,11-bis(4-fluorophenyl-2,4-dimethyl- 2,4-diazaspiro[5.5] undecane-1,3,5,9-tetraone (3a and 2,4-dimethyl-7,11-bis (4-(trifluoromethylphenyl-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone (3b were characterized by single-crystal X-ray diffraction, FT-IR and NMR techniques. The optimized geometrical parameters, infrared vibrational frequencies and NMR chemical shifts of the studied compounds have also been calculated using the density functional theory (DFT method, using Becke-3-Lee-Yang-Parr functional and the 6-311G(d,p basis set. There is good agreement between the experimentally determined structural parameters, vibrational frequencies and NMR chemical shifts of the studied compounds and those predicted theoretically. The calculated natural atomic charges using NBO method showed higher polarity of 3a compared to 3b.The calculated electronic spectra are also discussed based on the TD-DFT calculations.

  2. Synthesis, electronic structure, elastic properties, and interfacial behavior of icosahedral boron-rich solids

    Energy Technology Data Exchange (ETDEWEB)

    Hunold, Oliver

    2017-08-01

    Boron-rich solids are commonly characterized by icosahedral clusters, where 12 B atoms form an icosahedron, giving rise to outstanding mechanical and transport properties. However, broader applications are limited due to the high synthesis temperature required to obtain the icosahedra-based crystalline structure. Utilizing high power pulsed magnetron sputtering (HPPMS), the deposition temperature may be lowered as compared to direct current magnetron sputtering by enhanced surface diffusion. Therefore, HPPMS was utilized to investigate the influence of the substrate temperature on the structural evolution of B-rich Al-Y-B thin films. The formation of the intended AlYB{sub 14} phase together with the (Y,Al)B{sub 6} impurity phase, containing 1.8 at.% less B than AlYB{sub 14}, was observed at a growth temperature of 800 C and hence 600 C below the bulk synthesis temperature. Based on density functional theory (DFT) calculations it is inferred that minute compositional variations may lead to formation of competing phases, such as (Y,Al)B{sub 6}. Furthermore, 800 C still limits the usage significantly. Therefore, quantum mechanical material design was applied to identify phases with even higher phase stabilities compared to AlYB{sub 14}. Phase stability of T{sub 0.75}Y{sub 0.75}B{sub 14} (T= Sc, Ti, V, Y, Zr, Nb, Si) critically depends on the exact magnitude of charge transferred by T and Y to the B icosahedra. The highest phase stabilities have been identified for Sc{sub 0.75}Y{sub 0.75}B{sub 14}, Ti{sub 0.75}Y{sub 0.75}B{sub 14}, and Zr{sub 0.75}Y{sub 0.75}B{sub 14}. ln combination with Young's modulus values up to 517 GPa these phases are very interesting from a wear-resistance point of view. Still high synthesis temperatures limit the use of such systems onto technologically relevant substrate materials. However, amorphous B-rich solids, which can be synthesized without additional heating, exhibit attractive mechanical and electrical properties. Within these

  3. Halogen derivatives of benzo- and dibenzocrown ethers: synthesis, structure, properties and application

    International Nuclear Information System (INIS)

    Pluzhnik-Gladyr, S M

    2016-01-01

    Methods of synthesis of halogenated benzo- and dibenzocrown ether derivatives are surveyed: halogenation of benzo- and dibenzocrown ethers with molecular halogens, N-halosuccinimides in the solid phase and different media (water, ethanol, halohydrocarbons) and hypohalites in water, as well as the 'assembly' method. Reactions of these compounds are considered: synthesis of phosphorus-containing crown ethers, organometallic synthesis, the Heck and Sonogashira reactions, synthesis of acetylene derivatives and other reactions. Special attention is focused on the complexing properties of halogenated benzocrown ethers with respect to ionic guests and neutral organic molecules. The possibility of synthesis of complexes of such compounds in the solid phase is demonstrated. The extraction and sorption properties of halogenated benzo- and dibenzocrown ethers are considered. Examples of practical use of these compounds are presented. The bibliography includes 203 references

  4. Synthesis, characterization and nano-structuration of poly-thiophene derivatives for organic photovoltaic solar cells

    International Nuclear Information System (INIS)

    Berson, S.

    2007-10-01

    This work is devoted to the synthesis of poly-thiophene derivatives with low bandgap and preserving high oxidation potential. Disubstituted thiophenes and 'Donor-Acceptor' bi-thiophenes were synthesized and then polymerized. The side chains of these polymers, donor or acceptor, were modified in order to tune the properties of material as well from the optical point of view as electrochemical. These polymers were also tested in blend with PCBM in bulk-heterojunction photovoltaic cells. Voc delivered by the devices showed a linear dependence according to the potential of oxidation of the polymers. Copolymers containing cyano-thiophene and alkyl- or alkoxy-thiophene showed values of 0.8 V. However, in spite of power conversion efficiency of 1 %, these performances remain lower than the one obtained with the P3HT. Optimizations in terms of morphology are certainly necessary. Indeed, the morphology of the active layer plays a key role in obtaining high power conversion efficiency. An original technique of nano-structuration of the polymer on a nano-metric scale was developed during this work, leading to the development of fibrillar P3HT. These nano-structures, presenting an important degree of order, are formed spontaneously in solution. Their rate compared to amorphous material is perfectly controllable and adjustable in solution and in solid state. Measurements of mobilities show a strong improvement of the transport of load within these fibrillar layers compared to a traditional film of P3HT obtained without annealing. Power conversion efficiencies of 3.6% on glass and 3.3 % on plastic were reached without annealing. (author)

  5. Synthesis, characterization and nano-structuration of poly-thiophene derivatives for organic photovoltaic solar cells

    International Nuclear Information System (INIS)

    Berson, S.

    2007-10-01

    This work is devoted to the synthesis of poly-thiophene derivatives with low bandgap and preserving high oxidation potential. Di-substituted thiophenes and 'Donor-Acceptor' bi-thiophenes were synthesized and then polymerized. The side chains of these polymers, donor or acceptor, were modified in order to tune the properties of material as well from the optical point of view as electrochemical. These polymers were also tested in blend with PCBM in bulk-heterojunction photovoltaic cells. Voc delivered by the devices showed a linear dependence according to the potential of oxidation of the polymers. Copolymers containing cyano-thiophene and alkyl- or alkoxy-thiophene showed values of 0.8 V. However, in spite of power conversion efficiency of 1 %, these performances remain lower than the one obtained with the P3HT. Optimizations in terms of morphology are certainly necessary. Indeed, the morphology of the active layer plays a key role in obtaining high power conversion efficiency. An original technique of nano-structuration of the polymer on a nano-metric scale was developed during this work, leading to the development of fibrillary P3HT. These nano-structures, presenting an important degree of order, are formed spontaneously in solution. Their rate compared to amorphous material is perfectly controllable and adjustable in solution and in solid state. Measurements of mobilities show a strong improvement of the transport of load within these fibrillary layers compared to a traditional film of P3HT obtained without annealing. Power conversion efficiencies of 3.6 % on glass and 3.3 % on plastic were reached without annealing. (author)

  6. Structural design, synthesis and pharmacological evaluation of thiazoles against Trypanosoma cruzi.

    Science.gov (United States)

    de Oliveira Filho, Gevanio Bezerra; Cardoso, Marcos Veríssimo de Oliveira; Espíndola, José Wanderlan Pontes; Oliveira E Silva, Dayane Albuquerque; Ferreira, Rafaela Salgado; Coelho, Pollyanne Lacerda; Anjos, Pâmela Silva Dos; Santos, Emanuelle de Souza; Meira, Cássio Santana; Moreira, Diogo Rodrigo Magalhaes; Soares, Milena Botelho Pereira; Leite, Ana Cristina Lima

    2017-12-01

    Chagas disease is one of the most significant health problems in the American continent. benznidazole (BDZ) and nifurtimox (NFX) are the only drugs approved for treatment and exhibit strong side effects and ineffectiveness in the chronic stage, besides different susceptibility among T. cruzi DTUs (Discrete Typing Units). Therefore, new drugs to treat this disease are necessary. Thiazole compounds have been described as potent trypanocidal agents. Here we report the structural planning, synthesis and anti-T. cruzi evaluation of a new series of 1,3-thiazoles (7-28), which were designed by placing this heterocycle instead of thiazolidin-4-one ring. The synthesis was conducted in an ultrasonic bath with 2-propanol as solvent at room temperature. By varying substituents attached to the phenyl and thiazole rings, substituents were observed to retain, enhance or greatly increase their anti-T. cruzi activity. In some cases, methyl at position 5 of the thiazole (compounds 9, 12 and 23) increased trypanocidal property. The exchange of phenyl for pyridinyl heterocycle resulted in increased activity, giving rise to the most potent compound against the trypomasigote form (14, IC 50trypo  = 0.37 μM). Importantly, these new thiazoles were toxic for trypomastigotes without affecting macrophages and cardiomyoblast viability. The compounds were also evaluated against cruzain, and five of the most active compounds against trypomastigotes (7, 9, 12, 16 and 23) inhibited more than 70% of enzymatic activity at 10 μM, among which compound 7 had an IC 50 in the submicromolar range, suggesting a possible mechanism of action. In addition, examination of T. cruzi cell death showed that compound 14 induces apoptosis. We also examined the activity against intracellular parasites, revealing that compound 14 inhibited T. cruzi infection with potency similar to benznidazole. The antiparasitic effect of 14 and benznidazole in combination was also investigated against trypomastigotes and

  7. Actinide oxides synthesis in molten chloride. Structural studies and reaction mechanisms

    International Nuclear Information System (INIS)

    Vigier, J.F.

    2012-01-01

    Pyrochemical processes are studied as potential alternatives to hydrochemical processes for spent nuclear fuel treatment. The CEA pyrochemical process led to a molten LiCl-CaCl 2 (30-70% mol) salt at 700 C with solubilized actinides at the oxidation state (III). The study developed in this thesis concerns actinide oxides synthesis in this media for nuclear fuel re-fabrication. This synthesis was done by wet argon sparging. First, this conversion method is described for neodymium (III) and cerium (III) co-conversion. The conversion rates are around 99.9%. The obtained powders contain mixed oxychloride Ce 1-x Nd x OCl as main component, with a small amount of mixed oxide Ce 1-x Nd x O 2-0,5x for the high cerium ratio. A second oxychloride CeIV(Nd 0.7 Ce 0.3 ) III O 3 Cl is obtained in specific conditions and in very low quantity. The structure of this oxychloride is described in this study. The partially oxidative property of the conversion method induces the oxidation of a part of cerium (III) to oxidation state (IV). In the case of uranium (III) conversion by wet argon sparging, all the uranium is oxidized and give the oxide UO 2 as single compound. The conversion rate for this element is over 99.9% in the molten chloride, but significant amount of uranium is lost by volatilization during the conversion. The study shows the oxygen sensitivity of uranium during the conversion, inducing oxidation over the oxidation state (IV), and giving UO 2+x or uranate CaUO 4 . As a consequence, oxygen led to calcium pollution in the precipitate. Finally, the U(III) and Pu(III) co-conversion study shows the highest precipitation sensitivity of uranium (III) in comparison with plutonium (III), responsible of a successive conversion of the two elements, giving an oxide mixture of UO 2 et PuO 2 with quantitative conversion rate. Surprisingly, the conversion of Pu(III) in the same conditions led to a mixture of PuO 2 and PuOCl, characteristic of a partial oxidation from Pu (III) to Pu

  8. High-pressure synthesis, crystal structure and magnetic properties of TlCrO3 perovskite.

    Science.gov (United States)

    Yi, Wei; Matsushita, Yoshitaka; Katsuya, Yoshio; Yamaura, Kazunari; Tsujimoto, Yoshihiro; Presniakov, Igor A; Sobolev, Alexey V; Glazkova, Yana S; Lekina, Yuliya O; Tsujii, Naohito; Nimori, Shigeki; Takehana, Kanji; Imanaka, Yasutaka; Belik, Alexei A

    2015-06-21

    TlMO(3) perovskites (M(3+) = transition metals) are exceptional members of trivalent perovskite families because of the strong covalency of Tl(3+)-O bonds. Here we report on the synthesis, crystal structure and properties of TlCrO(3) investigated by Mössbauer spectroscopy, specific heat, dc/ac magnetization and dielectric measurements. TlCrO(3) perovskite is prepared under high pressure (6 GPa) and high temperature (1500 K) conditions. The crystal structure of TlCrO(3) is refined using synchrotron X-ray powder diffraction data: space group Pnma (no. 62), Z = 4 and lattice parameters a = 5.40318(1) Å, b = 7.64699(1) Å and c = 5.30196(1) Å at 293 K. No structural phase transitions are found between 5 and 300 K. TlCrO(3) crystallizes in the GdFeO(3)-type structure similar to other members of the perovskite chromite family, ACrO(3) (A(3+) = Sc, In, Y and La-Lu). The unit cell volume and Cr-O-Cr bond angles of TlCrO(3) are close to those of DyCrO(3); however, the Néel temperature of TlCrO(3) (TN≈ 89 K) is much smaller than that of DyCrO(3) and close to that of InCrO(3). Isothermal magnetization studies show that TlCrO(3) is a fully compensated antiferromagnet similar to ScCrO(3) and InCrO(3), but different from RCrO(3) (R(3+) = Y and La-Lu). Ac and dc magnetization measurements with a fine step of 0.2 K reveal the existence of two Néel temperatures with very close values at T(N2) = 87.0 K and T(N1) = 89.3 K. Magnetic anomalies near T(N2 )are suppressed by static magnetic fields and by 5% iron doping.

  9. Nanoparticles of the superconductor MgB2: structural characterization and in situ study of synthesis kinetics

    International Nuclear Information System (INIS)

    Cui Chunxiang; Liu Debao; Shen Yutian; Sun Jinbin; Meng Fanbin; Wang Ru; Liu Shuangjin; Greer, A.L.; Chen, S.K.; Glowacki, B.A.

    2004-01-01

    Single-crystal MgB 2 nanoparticles, with diameters in the range 20-100 nm, have been synthesized in situ in the sample chamber of an X-ray diffractometer. The reaction kinetics are analyzed and related to the atomic-level structure of the particles as observed by high-resolution electron microscopy. Synthesis conditions may have a significant influence on microstructure and superconducting properties

  10. One-pot synthesis of Fe-Co nanospheres by modified polyol process and their structural, magnetic studies

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, G; Babu, D Rajan [Advanced Materials Research Centre, Crystal Growth and Crystallography Division, School of Advanced Sciences, VIT University, Vellore-632 014 (India); Saravanan, P, E-mail: drajanbabu@vit.ac.in [Advanced Magnetics Group, Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India)

    2011-04-01

    Fe-Co nanoparticles stabilized by polyvinylpyrrolidone (PVP) have been prepared using modified polyol process. When 5 mmol of PVP was used, aggregated nanoparticles with irregular shapes were resulted; whereas on increasing the PVP concentration to 10 mmol, highly spherical nanoparticles were obtained. In the present work, the influence of non-ionic stabilizer viz. PVP on the synthesis of spherical nanoparticles and their structural, macromagnetic properties have been reported.

  11. Synthesis, properties, structure and thermochemistry of hexa-aqua-tris (N,N-dimethylformamide) lanthanide tri fluoro methane sulfonates

    International Nuclear Information System (INIS)

    Araujo Melo, D.M. de.

    1989-01-01

    Addition compounds between several lanthanide salts and dimethylformamide (DMF) have been described in the literature. This thesis reports the synthesis and characterization of the compounds of general composition Ln (C H 3 SO 3 ) 3 . 3 DMF.6 H 3 O) (Ln = La - Ho) and Ln (C H 3 SO 3 ) 3 DMF.6 H 2 O (Ln = Er - Lu). The structure of the neodymium compound, isomorphous with the series, is also described. The enthalpy variations were determined by solution calorimetry. (author)

  12. Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis

    Directory of Open Access Journals (Sweden)

    Zheng Yang

    2016-02-01

    Full Text Available Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3, were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473, one of important cancer drugs target.

  13. Comparison among structural characteristics of Ce1-xCuxO2 nanocatalysts obtained by two methods of distinct synthesis

    International Nuclear Information System (INIS)

    Neiva, L.S.; Bispo, A.; Santos, P.T.A.; Costa, A.C.F.M.; Gama, L.; Mascarenhas, A.J.S.

    2009-01-01

    The objective this work is to synthesize nano catalysts Ce 1-x Cu x O 2 type by the synthesis methods of the combustion reaction and Pechini. The value of the concentration (x) of the element dope (Cu) varies between 0,1 and 0,5 mols. It intends evaluate that form the synthesis method influences in the physical structural characteristics of this material. nano catalysts were characterized by ray- X diffraction. The results showed nano catalysts formation with a formed structure for the most part by the phase CeO 2 , as it was expected, since this is the hostess matrix of the element dope (Cu). Nano catalysts obtained by the method Pechini presents crystallinity larger deg, according with patterns of ray-X. Thus, it was concluded that synthesis employee method the kind in the methodology, as well as the value of the concentration of the element dope has influence on the final structural characteristics of the developed material. (author)

  14. Synthesis, characterization and single crystal structures of chiral Schiff base and its tetranuclear palladium complex with Pdsbnd Osbnd Pd bridging and Pdsbnd Pd bonds

    Science.gov (United States)

    Rajegowda, H. R.; Kumar, P. Raghavendra; Hosamani, Amar; Butcher, R. J.; Naveen, S.; Lokanath, N. K.

    2018-03-01

    A new chiral Schiff base ligand 2-{N-[(2S)-(1-hydroxy-3-phenylpropan-2-yl]ethanimidoyl} phenol ((S)sbnd H2L) was obtained by acid catalyzed condensation of (2S)-(-)-2-amino-3-phenyl-1-propanol with 2‧-hydroxyacetophenone. The palladium complex was prepared by treating a solution of (S)sbnd H2L in acetone with a solution of Na2PdCl4 in water in 1:1 M ratio. The new ligand and its complex were characterized by FT-IR, 1H, 13C{1H} NMR spectroscopy, polarimetry and elemental analysis and their molecular structures were determined by single crystal X-ray diffraction. Both the compounds crystallizes in monoclinic system in the space group P21. There exists an intra [Osbnd H ⋯N (1.62(5) Å)] and intermolecular [Osbnd H ⋯O (1.53(5) Å) and Csbnd H ⋯O (2.59 Å)] hydrogen bonding and secondary interactions in the crystal of (S)sbnd H2L. The structure of the palladium complex was found very interesting wherein the ligand coordinated to metal center as tridentate dianionic (O-, N, O-) fashion, (S)-L, resulting in a tetranuclear palladium cluster, [Pd4((S)-L)4]. In these supramolecular structures phenolate oxygen coordinated to Pd(II) ion as Pdsbnd O terminal bonds [1.934(12) - 1.977(11) Å] and the alkoxide oxygen coordinated as Pdsbnd Osbnd Pd bridging bonds [1.993(11) - 2.012(12) Å]. The Pdsbnd N bond lengths found were in the range of 1.949(13) to 1.919(12) Å. There exists two asymmetric tetranuclear complex molecules in its crystal lattice. There exists very strong metal-metal bond interaction, Pd(2)sbnd Pd(3) [3.0410(18) Å] and Pd(6)sbnd Pd(7) [3.0517(19) Å] respectively in the two asymmetric units.

  15. Facile and tunable synthesis of hierarchical mesoporous silica materials ranging from flower structure with wrinkled edges to hollow structure with coarse surface

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Nanjing, E-mail: nanjing.hao@dartmouth.edu [Dartmouth College, Thayer School of Engineering (United States); Li, Laifeng; Tang, Fangqiong, E-mail: tangfq@mail.ipc.ac.cn [Chinese Academy of Sciences, Technical Institute of Physics and Chemistry (China)

    2016-11-15

    Mesoporous silica materials have attracted great attention in many fields. However, facile and tunable synthesis of hierarchical mesoporous silica structures is still a big challenge, and thus the development of them still lags behind. Herein, well-defined mesoporous silica flower structure with wrinkled edges and mesoporous silica hollow structure with coarse surface were synthesized simply by using poly(vinylpyrrolidone) and hexadecylamine as cotemplates in different water/ethanol solvent systems. The shape evolution from flower to hollow can be easily realized by tuning the volume ratio of water to ethanol, and the yields of both materials can reach gram scale. The formation mechanisms of mesoporous silica flower and hollow structures were also experimentally investigated and discussed. These novel hierarchical structures having unique physicochemical properties may bring many interesting insights into scientific research and technological application.

  16. Synthesis, Internal Structure, and Formation Mechanism of Monodisperse Tin Sulfide Nanoplatelets

    NARCIS (Netherlands)

    de Kergommeaux, Antoine; Lopez-Haro, Miguel; Pouget, Stéphanie; Zuo, Jian-Min; Lebrun, Colette; Chandezon, Frédéric; Aldakov, Dmitry; Reiss, Peter

    2015-01-01

    Tin sulfide nanoparticles have a great potential for use in a broad range of applications related to solar energy conversion (photovoltaics, photocatalysis), electrochemical energy storage, and thermoelectrics. The development of chemical synthesis methods allowing for the precise control of size,

  17. Nonenzymatic synthesis of RNA and DNA oligomers on hexitol nucleic acid templates: the importance of the A structure

    Science.gov (United States)

    Kozlov, I. A.; Politis, P. K.; Van Aerschot, A.; Busson, R.; Herdewijn, P.; Orgel, L. E.; Bada, J. L. (Principal Investigator); Dolan, M. (Principal Investigator)

    1999-01-01

    Hexitol nucleic acid (HNA) is an analogue of DNA containing the standard nucleoside bases, but with a phosphorylated 1,5-anhydrohexitol backbone. HNA oligomers form duplexes having the nucleic acid A structure with complementary DNA or RNA oligomers. The HNA decacytidylate oligomer is an efficient template for the oligomerization of the 5'-phosphoroimidazolides of guanosine or deoxyguanosine. Comparison of the oligomerization efficiencies on HNA, RNA, and DNA decacytidylate templates under various conditions suggests strongly that only nucleic acid double helices with the A structure support efficient template-directed synthesis when 5'-phosphoroimidazolides of nucleosides are used as substrates.

  18. The in vitro synthesis of β-galactosidase induced in a subcellular structure of Escherichia coli (1961)

    International Nuclear Information System (INIS)

    Nisman, B.; Kayser, A.; Demailly, J.; Genin, C.

    1961-01-01

    Isopropyl-thio-galactoside (IPTG), an inducer of 3-galactosidase, makes it possible to synthesise this enzyme in vitro with the subcellular structure (P 1 ). The enzyme is isolated from the bacteria Escherichia coli K 12 which are inductive but not induced. The incorporation of radioactive amino-acids, which is stimulated by the presence of an inducer, was studied during the course of the enzyme synthesis. Saccharose suppresses the induction of β-galactosidase. The presence of a specific inhibitor in the structure studied is considered. (authors) [fr

  19. Synthesis and structure verification of the vaccine adjuvant QS-7-Api. Synthetic access to homogeneous Quillaja saponaria immunostimulants.

    Science.gov (United States)

    Deng, Kai; Adams, Michelle M; Gin, David Y

    2008-05-07

    QS-7-Api is an exceedingly potent immuno-adjuvant isolated from the bark of Quillaja saponaria. It is significantly less toxic than QS-21, a related saponin that is currently the favored adjuvant in anticancer and antiviral vaccine clinical trials. Tedious isolation/purification protocols and uncertainty in its structural constitution have hindered the clinical development of QS-7. A chemical synthesis of QS-7-Api is described, providing structural verification of the adjuvant. A novel semisynthetic sequence to QS-7-Api has also been established, greatly facilitating access to QS-7 for preclinical and clinical evaluation.

  20. One-pot reverse microemulsion synthesis of core-shell structured YVO4:Eu3+@SiO2 nanocomposites

    Science.gov (United States)

    Liu, Lina; Yue, Surong; Zhang, Yongsheng; Qin, Ruifei; Liu, Lishuang; Zhang, Dongmei; Sun, Ruirui; Chen, Linfeng

    2015-01-01

    Core-shell structured YVO4:Eu3+@SiO2 nanocomposite particles were synthesized using a one-pot reverse microemulsion method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV absorption spectra, and photoluminescent spectra. The nanocomposite particles are well-dispersed and about 20 nm in average size. The synthesis method is of one-pot, simplifying the preparation of this kind of core-shell structured nanocomposites. The formation process of these nanocomposite particles is suggested and the photoluminescence properties of them are studied and compared with those of uncoated YVO4:Eu3+ sample.

  1. Liquid phase low temperature method for production of methanol from synthesis gas and catalyst formulations therefor

    Science.gov (United States)

    Mahajan, Devinder

    2005-07-26

    The invention provides a homogenous catalyst for the production of methanol from purified synthesis gas at low temperature and low pressure which includes a transition metal capable of forming transition metal complexes with coordinating ligands and an alkoxide, the catalyst dissolved in a methanol solvent system, provided the transition metal complex is not transition metal carbonyl. The coordinating ligands can be selected from the group consisting of N-donor ligands, P-donor ligands, O-donor ligands, C-donor ligands, halogens and mixtures thereof.

  2. Semisynthetic macrolide antibacterials derived from tylosin. Synthesis and structure-activity relationships of novel desmycosin analogues.

    Science.gov (United States)

    Mutak, Stjepan; Marsić, Natasa; Kramarić, Miroslava Dominis; Pavlović, Drazen

    2004-01-15

    A series of 20-O-substituted and 3,20-di-O-substituted derivatives of desmycosin were synthesized and their biological properties were evaluated. In particular, we have synthesized numerous side chain modified analogues of desmycosin as well as some analogues possessing a combination of modified side chain and alternative C-3 substituents. Thus, alpha,beta-unsaturated analogues of desmycosin (2), tylosin (1), 10,11,12,13-tetrahydrotylosin (11), and 2,3-didehydrodesmycosin (13) were prepared from the corresponding aldehydes by a Wittig reaction with the stabilized ylides (a-d), generating a trans-double bond, followed by modified Pfitzner-Moffat oxidation of the C-3 hydroxyl group. To evaluate the importance of the C-3 position of desmycosin for biological activity, the C-3 substituted derivatives were synthesized by a standard sequence of protective group chemistry followed by Wittig reaction and esterification as the key steps. For the attachment of the C-3 ester functionality, a mixed anhydride protocol was adopted. Reaction proceeded smoothly to give corresponding esters in yields ranging from 70 to 80%. Base- and acid-catalyzed rearrangement products including desmycosin 8,20-aldols (24a and 24b) and desmycosin 3,19-aldol (25) are also described. Parallel array synthesis and purification techniques allowed for the rapid exploration of structure-activity relationships within this class and for the improvement in potency. In vitro evaluation of these derivatives demonstrated good antimicrobial activity against Gram-positive bacteria for most of the compounds. The present derivatives of 16-membered macrolides were active against MLS(B)-resistant strains that were inducibly resistant, but not those constitutively resistant to erythromycin.

  3. A base-free thorium-terminal-imido metallocene: synthesis, structure, and reactivity.

    Science.gov (United States)

    Ren, Wenshan; Zi, Guofu; Fang, De-Cai; Walter, Marc D

    2011-11-04

    The synthesis, structure, and reactivity of a base-free thorium terminal-imido metallocene have been comprehensively studied. Treatment of thorium metallocenes [{η(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)ThMe(2)] and [{η(5)-1,3-(Me(3)C)(2)C(5)H(3)}(2)ThMe(2)] with RNH(2) gives diamides [{η(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)Th(NHR)(2)] (R=Me (7), p-tolyl (8)) and [{η(5)-1,3-(Me(3)C)(2)C(5)H(3)}(2)Th(NH-p-tolyl)(2)] (9), respectively. Diamides 7 and 9 do not eliminate methylamine or p-toluidine, but sublime without decomposition at 150 °C under vacuum (0.01 mmHg), whereas diamide 8 is converted at 140 °C/0.01 mmHg into the primary amine p-tolyl-NH(2) and [{η(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)Th=N(p-tolyl)] (10), which may be isolated in pure form. Imido metallocene 10 does not react with electrophiles such as alkylsilyl halides; however, it reacts with electron-rich or unsaturated reagents. For example, reaction of 10 with sulfur affords the metallacycle [{η(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)Th{N(p-tolyl)S-S}]. Imido 10 is an important intermediate in the catalytic hydroamination of internal alkynes, and an efficient catalyst for the trimerization of PhCN. Density functional theory (DFT) studies provide a detailed understanding of the experimentally observed reactivity patterns. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. A base-free thorium-terminal-imido metallocene: synthesis, structure, and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Wenshan; Zi, Guofu; Fang, De-Cai [Department of Chemistry, Beijing Normal University (China); Walter, Marc D. [Institut fuer Anorganische und Analytische Chemie, Technische Universitaet Braunschweig (Germany)

    2011-11-04

    The synthesis, structure, and reactivity of a base-free thorium terminal-imido metallocene have been comprehensively studied. Treatment of thorium metallocenes [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}ThMe{sub 2}] and [{η"5-1,3-(Me_3C)_2C_5H_3}{sub 2}ThMe{sub 2}] with RNH{sub 2} gives diamides [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th(NHR){sub 2}] (R=Me (7), p-tolyl (8)) and [{η"5-1,3-(Me_3C)_2C_5H_3}{sub 2}Th(NH-p-tolyl){sub 2}] (9), respectively. Diamides 7 and 9 do not eliminate methylamine or p-toluidine, but sublime without decomposition at 150 C under vacuum (0.01 mmHg), whereas diamide 8 is converted at 140 C/0.01 mmHg into the primary amine p-tolyl-NH{sub 2} and [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th=N(p-tolyl)] (10), which may be isolated in pure form. Imido metallocene 10 does not react with electrophiles such as alkylsilyl halides; however, it reacts with electron-rich or unsaturated reagents. For example, reaction of 10 with sulfur affords the metallacycle [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th{N(p-tolyl)S-S}]. Imido 10 is an important intermediate in the catalytic hydroamination of internal alkynes, and an efficient catalyst for the trimerization of PhCN. Density functional theory (DFT) studies provide a detailed understanding of the experimentally observed reactivity patterns. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. New strategies for the synthesis of naphthoquinones employing Cu(II) complexes: Crystal structures and cytotoxicity

    Science.gov (United States)

    Azeredo, Nathália F. B.; Souza, Fabrícia P.; Demidoff, Felipe C.; Netto, Chaquip D.; Resende, Jackson A. L. C.; Franco, Roberto W. A.; Colepicolo, Pio; Ferreira, Ana M. C.; Fernandes, Christiane

    2018-01-01

    The syntheses, physico-chemical characterization and cytotoxicity toward three human cell lines (standard and resistant sarcoma cells, and fibroblast) of a new copper(II) complex [Cu(HBPA)(L1)Cl]·3H2O 2 are reported. Complex 2 was obtained through the reaction between the ligand stilbene-quinone (HL1) and Cu[HBPA]Cl21, where HBPA = 2-hydroxybenzyl-2pyridylmethylamine. The synthesis of HL1 was performed in high yield through Heck reaction on PEG-400. X-ray diffraction and solution studies (UV-Vis, EPR, ESI(+)-MS and ESI(+)-MS/MS) were performed for complex 2, in which the copper(II) center is coordinated to the quinone in its deprotonated form, to the ligand HBPA and to a chloro ligand. Similar reaction employing CuCl2·2H2O, instead of Cu[HBPA]Cl21 and HL1, has resulted in the obtainment of a furano-o-naphtoquinone (L2) with 99% selectivity, suggesting a new methodology to cyclize the ligand HL1. In order to obtain the analogous para-isomer (L3), and to evaluate the isomerism influence on cytotoxicity activity, a cyclization reaction of HL1 with NBS (N-bromosuccinimide) was also performed, which resulted in the obtainment of L2 (8%) and L3 (13%). X-ray diffraction studies were performed for L2 and complex 2, and the description of their structure elucidated. Results from MTT assay revealed that complex 2 is more active against sarcoma cell lines (MES-SA/Dx5 and MES-SA) than both the free ligand HL1 and complex 1, reducing cell viability to less than 50 μmol L-1. L2 was the most active in the series, presenting cytotoxicity against resistant MES-SA/Dx5 and its standard MES-SA cell line, respectively, three and ten times higher than the current drug doxorubicin.

  6. Constitutional Isomers of Dendrimer-like Star Polymers: Design, Synthesis and Conformational and Structural Properties

    Energy Technology Data Exchange (ETDEWEB)

    Pople, John A

    2001-03-22

    The design, synthesis and solution properties of six constitutional isomers of dendrimer-like star polymers is described. Each of the polymers have comparable molecular weights ({approx} 80,000 g/mol), narrow polydispersities (< 1.19) and an identical number of branching junctures (45) and surface hydroxyl functionalities (48). The only difference in the six isomers is the placement of the branching junctures. The polymers are constructed from high molecular weight poly(e-caprolactone) with branching junctures derived from 2,2'-bis(hydroxylmethyl) propionic acid (bis-MPA) emanating from a central core. The use of various generations of dendritic initiators and dendrons coupled with the ring opening polymerization of e-caprolactones allowed a modular approach to the dendrimer-like star polymer isomers. The most pronounced effects on the physical properties/morphology and hydrodynamic volume was for those polymers in which the branching was distributed throughout the sample in a dendrimer-like fashion. The versatility of this approach has provided the possibility of understanding the relationship between architecture and physical properties. Dynamic light scattering and small angle X-ray scattering techniques were used to determine the hydrodynamic radius Rh and radius of gyration Rg respectively. The relationship between Rg and molecular weight was indicative of a compact star-like structure, and did not show advanced bias towards either the dense core or dense shell models. The radial density distribution of the isomers was therefore modeled according to a many arm star polymer, and good agreement was found with experimental measures of Rh/Rg.

  7. Bourbaki's structure theory in the problem of complex systems simulation models synthesis and model-oriented programming

    Science.gov (United States)

    Brodsky, Yu. I.

    2015-01-01

    The work is devoted to the application of Bourbaki's structure theory to substantiate the synthesis of simulation models of complex multicomponent systems, where every component may be a complex system itself. An application of the Bourbaki's structure theory offers a new approach to the design and computer implementation of simulation models of complex multicomponent systems—model synthesis and model-oriented programming. It differs from the traditional object-oriented approach. The central concept of this new approach and at the same time, the basic building block for the construction of more complex structures is the concept of models-components. A model-component endowed with a more complicated structure than, for example, the object in the object-oriented analysis. This structure provides to the model-component an independent behavior-the ability of standard responds to standard requests of its internal and external environment. At the same time, the computer implementation of model-component's behavior is invariant under the integration of models-components into complexes. This fact allows one firstly to construct fractal models of any complexity, and secondly to implement a computational process of such constructions uniformly-by a single universal program. In addition, the proposed paradigm allows one to exclude imperative programming and to generate computer code with a high degree of parallelism.

  8. Structural characterization of birnessite: influence of the way of synthesis; Caracterisation structurale de la birnessite: influence du protocole de synthese

    Energy Technology Data Exchange (ETDEWEB)

    Gaillot, A.C.

    2002-01-15

    Birnessite is a lamellar manganese oxide whose layers are built up of edge sharing MnO{sub 6} octahedra. The presence of hetero-valent Mn cations and/or of vacant sites in these layers leads to a charge deficit compensated for by the presence of hydrated cations in the interlayer space. Because of their high specific area and of their strong oxidative character, these ubiquitous manganese oxides play a fundamental role in the fate of organic and metallic pollutants in the environment, but our imperfect knowledge of their structure limits the understanding and the modeling of this impact. This study aimed at classifying all different kinds of birnessite obtained using existing synthesis protocols according to two relevant criteria: layer symmetry and layer stacking mode, and at determining the structure of several essential varieties using X-ray and electron diffraction. Layers of hydrothermal birnessite contain vacant sites and, as a result, possess an hexagonal symmetry. Their stacking mode is 3R. In high-temperature birnessites, adjacent layers have an opposite orientation, which results in a two-layer polytype. The symmetry of these layers, linked to the origin of the layer charge deficit, depends on the temperature of synthesis. At 800 C the presence of vacant sites results in an hexagonal symmetry (2H polytype). At 1000 C, the layer charge deficit originates from the presence of Mn{sup 3+} cations in the layer lowering the layer symmetry (2O polytype). A variety of chemical and structural heterogeneities was also described in these samples, along with the occurrence of a new type of structural disorder. Finally we proved both the fundamental link between the origin of the layer charge and the layer symmetry, and the influence of physico-chemical parameters during synthesis (temperature, average manganese oxidation degree, nature of the interlayer cation) on the structure of the obtained compound. The chemical and thermal stabilities of these birnessites are

  9. Template-free synthesis of sub-micrometric cobalt fibers with controlled shape and structure. Characterization and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Lakhdar, Allagui [Laboratoire de Physique des Matériaux Lamellaires et Nano-Matériaux Hybrides, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Bizerte (Tunisia); Borges, Joao P. [i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Ben Haj Amara, Abdesslam [Laboratoire de Physique des Matériaux Lamellaires et Nano-Matériaux Hybrides, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Bizerte (Tunisia); Dakhlaoui-Omrani, Amel, E-mail: dakhlaoui_amel@yahoo.fr [Department of Chemistry, Faculty of Sciences and Arts-Khulais, University of Jeddah, Khulais, P. O. Box 355, Postal Code 21921 (Saudi Arabia); Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopôle de Bordj Cedria, BP 73, 8027 Soliman (Tunisia)

    2017-03-01

    Sub-micrometric Co fibers were prepared via a modified polyol process at 90 °C under an external magnetic field of about 550 Oe, using ethelyne glycol as solvent and hydrazine as reducing agent. The structure, the size and the morphology of the as-elaborated products were highly controlled through properly monitoring the synthesis parameters (amount of NaOH added, the amount of the reducing agent, precursor’ concentration and precursors mixing protocol). The XRD characterization confirmed the formation of pure cobalt powders with either hexagonal compact (hcp) or face-centered-cubic (fcc) structure depending on the concentration of the metal precursor and sodium hydroxide. The scanning electron microscopy observations of the powders shows sub-micrometric fibers with about 0.4–0.6 µm in diameter and a length that could reach 15 µm. Fibers prepared at high reducing ratio were constituted of flower-like spheres that coalesce in the direction of the applied magnetic field. For their high contact surface, these fibers offer new opportunities for catalysis applications. The hysteresis loop measurements show an enhancement of the Hc of the as-obtained fibers compared to their bulk counterparts and permit to confirm the relationship between the structure and the magnetic properties of the materials. - Highlights: • Template free synthesis of cobalt sub-micrometric fibers. • High control of the structure the structure, the size and the morphology of the products through properly monitoring the synthesis parameters. • cobalt sub-micrometric fibers with enhanced magnetic properties compared to bulk cobalt.

  10. Synthesis of C-di-saccharidic compounds by radical cyclisation. Study of biological, structural and dynamic properties

    International Nuclear Information System (INIS)

    Rubinstenn, Gilles

    1996-01-01

    The synthesis of carbohydrate mimics and particularly of C-disaccharides, molecules in which the inter-glycosidic oxygen atom has been replaced by a methylene group, has become, this past two decades, an important challenge in organic chemistry. In the first chapter we present the synthesis of C-disaccharides from the neutral series by a silaketal tethering. The key step of this C-glycosylation is a radical macro-cyclisation. This strategy is applied to the synthesis of two analogues of natural, biologically active, products, the lactose and the Lewis x tri-saccharide. The biological activity of this mimetics is then evaluated. A new tethering strategy, based on the use of phosphorus III compounds, is applied, in the second chapter, to the building of C-disaccharides of the 2'-amino 2'- deoxy series. The third chapter deals with the structural and dynamics study of the C-glycosides prepared in chapter 1 by Nuclear Magnetic Resonance. A new methodology, studying the dipolar relaxation along an effective field, generated through an off-resonance RF field, allowed the precise measurement of longitudinal and transverse cross-relaxation rates. Structural and dynamics parameter thus derived are used as restraints for molecular modeling. The results of this study are then compared to those of the biological tests. (author) [fr

  11. Synthesis and Structure Characterization of Phenol-Urea-Formaldehyde Resins in the Presence of Magnesium Oxide as Catalyst

    Directory of Open Access Journals (Sweden)

    Dong-Bin Fan

    2014-08-01

    Full Text Available The objective of this research was to provide a useful approach of polymer synthesis for accelerating the fast cure of phenol-urea-formaldehyde (PUF resin as wood adhesive by optimizing its structure and composition. The PUF resins containing high contents of very reactive groups such as para-methylol groups were synthesized by reacting methylolurea, phenol, and formaldehyde in the presence of magnesium oxide (MgO as catalyst. The effects of synthesis parameters including F/(P + U, OH/P, and MgO/P mole ratios on the structure, composition, curing characteristics, and their relationships of PUF resins were investigated. The results indicated that MgO seemed to be an efficacious catalyst for PUF resin synthesis and promote its faster cure. The increase in the F/(P + U mole ratio or/and OH/P mole ratio appeared to be beneficial for the formation of para-methylol groups and cocondensed methylene linkages between phenolic methylol groups and urea units, and for the removal of unreacted urea. In case of Catalyst/P mole ratio, an appropriate dosage of added metal-ion was very important for synthesizing the high-content reactive groups of PUF resins, otherwise leading to the reverse effects.

  12. Total chemical synthesis, refolding, and crystallographic structure of fully active immunophilin calstabin 2 (FKBP12.6).

    Science.gov (United States)

    Bacchi, Marine; Jullian, Magali; Sirigu, Serena; Fould, Benjamin; Huet, Tiphaine; Bruyand, Lisa; Antoine, Mathias; Vuillard, Laurent; Ronga, Luisa; Chavas, Leonard M G; Nosjean, Olivier; Ferry, Gilles; Puget, Karine; Boutin, Jean A

    2016-12-01

    Synthetic biology (or chemical biology) is a growing field to which the chemical synthesis of proteins, particularly enzymes, makes a fundamental contribution. However, the chemical synthesis of catalytically active proteins (enzymes) remains poorly documented because it is difficult to obtain enough material for biochemical experiments. We chose calstabin, a 107-amino-acid proline isomerase, as a model. We synthesized the enzyme using the native chemical ligation approach and obtained several tens of milligrams. The polypeptide was refolded properly, and we characterized its biophysical properties, measured its catalytic activity, and then crystallized it in order to obtain its tridimensional structure after X-ray diffraction. The refolded enzyme was compared to the recombinant, wild-type enzyme. In addition, as a first step of validating the whole process, we incorporated exotic amino acids into the N-terminus. Surprisingly, none of the changes altered the catalytic activities of the corresponding mutants. Using this body of techniques, avenues are now open to further obtain enzymes modified with exotic amino acids in a way that is only barely accessible by molecular biology, obtaining detailed information on the structure-function relationship of enzymes reachable by complete chemical synthesis. © 2016 The Protein Society.

  13. Multistep continuous-flow synthesis in medicinal chemistry: discovery and preliminary structure-activity relationships of CCR8 ligands.

    Science.gov (United States)

    Petersen, Trine P; Mirsharghi, Sahar; Rummel, Pia C; Thiele, Stefanie; Rosenkilde, Mette M; Ritzén, Andreas; Ulven, Trond

    2013-07-08

    A three-step continuous-flow synthesis system and its application to the assembly of a new series of chemokine receptor ligands directly from commercial building blocks is reported. No scavenger columns or solvent switches are necessary to recover the desired test compounds, which were obtained in overall yields of 49-94%. The system is modular and flexible, and the individual steps of the sequence can be interchanged with similar outcome, extending the scope of the chemistry. Biological evaluation confirmed activity on the chemokine CCR8 receptor and provided initial structure-activity-relationship (SAR) information for this new ligand series, with the most potent member displaying full agonist activity with single-digit nanomolar potency. To the best of our knowledge, this represents the first published example of efficient use of multistep flow synthesis combined with biological testing and SAR studies in medicinal chemistry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Solid-phase synthesis and structural characterization of highly substituted hydroxyproline-based 2,5-diketopiperazines

    DEFF Research Database (Denmark)

    Bianco; Sonksen; Roepstorff

    2000-01-01

    Two general solid-phase methods for the synthesis of a new class of 2,5-diketopiperazines (DKPs) containing the trans-4-hydroxy-L-proline amino acid residue (Hyp) have been developed. An N-protected hydroxyproline methyl ester was linked through the hydroxyl function to the Ellman resin. The synt......Two general solid-phase methods for the synthesis of a new class of 2,5-diketopiperazines (DKPs) containing the trans-4-hydroxy-L-proline amino acid residue (Hyp) have been developed. An N-protected hydroxyproline methyl ester was linked through the hydroxyl function to the Ellman resin....... The alkylation of hydroxyproline alpha CH was performed without control of the diastereoselectivity. During the final alkylation of the backbone, amide bond epimerization at the alpha-carbon atoms of the two amino acid residues was observed. The structures of representative DKPs were elucidated...

  15. Synthesis and structural data of a Fe-base sodium metaphosphate compound, NaFe(PO33

    Directory of Open Access Journals (Sweden)

    Xinghao Lin

    2015-09-01

    Full Text Available This data article contains the synthesis and structure information of a new Fe-base sodium metaphosphate compound, which is related to the research article entitled ‘Synthesis, structural, magnetic and sodium deinsertion/insertion properties of a sodium ferrous metaphosphate, NaFe(PO33’ by Lin et al. [1]. The research article has reported a new Fe-base metaphosphate compound NaFe(PO33, which is discovered during the exploration of the new potential electrode materials for sodium-ion batteries. In this data article, the synthesized process of this metaphosphate compound and the morphology of the obtained sample will be provided. The high-power XRD Rietveld refinement is applied to determine the crystal structure of this metaphosphate compound and the refinement result including the main refinement parameters, atomic coordinate and some important lattace parameters are stored in the cif file. Also, the refined structure has be evaluated by checkcif report and the result is also provided as the supplementary materials.

  16. Organosilane with gemini-type structure as the mesoporogen for synthesis of hierarchical porous ZSM-5 zeolite

    KAUST Repository

    Zhu, Haibo

    2016-02-08

    A new kind of organosilane (1,6-bis (diethyl(3-trimethoxysilylpropyl)ammonium) hexane bromide) with a gemini-type structure was prepared and used as a mesoporogen for the synthesis of hierarchical porous ZSM-5 zeolite. There are two quaternary ammonium centers along with double hydrolysable -RSi(OMe)3 fragments in the organosilane, which results in a strong interaction between this mesoporogen and silica-alumina gel. The organosilane can be easily incorporated into ZSM-5 zeolite structure during the crystallization process, and it was finally removed by calcination leading to secondary pores in ZSM-5. The synthesized ZSM-5 has been systematically studied by XRD, nitrogen adsorption, SEM, TEM, TG and solid-state one-dimensional (1D) and two-dimensional (2D) NMR, which reveals information on its detailed structure. It has a hierarchical porosity system, which combines the intrinsic micropores coming from the crystalline structure and irregular mesopores created by the organosilane template. Moreover, the mesoposity including pore size and volume within ZSM-5 can be systematically tuned by changing the organosilane/TEOS ratios, which confirms this organosilane has high flexibility of using as template for the synthesis of hierarchical porous zeolite.

  17. The Role of Template Structure and Synergism between Inorganic and Organic Structure Directing Agents in the Synthesis of UTL Zeolite

    Czech Academy of Sciences Publication Activity Database

    Shvets, O. V.; Kasian, N.; Zukal, Arnošt; Pinkas, Jiří; Čejka, Jiří

    2010-01-01

    Roč. 22, č. 11 (2010), s. 3482-3495 ISSN 0897-4756 R&D Projects: GA ČR GA203/08/0604; GA ČR GA104/07/0383 Institutional research plan: CEZ:AV0Z40400503 Keywords : UTL zeolite * synthesis * zeolite molecular sietes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.400, year: 2010

  18. Glucuronidated Flavonoids in Neurological Protection: Structural Analysis and Approaches for Chemical and Biological Synthesis.

    Science.gov (United States)

    Docampo, Maite; Olubu, Adiji; Wang, Xiaoqiang; Pasinetti, Giulio; Dixon, Richard A

    2017-09-06

    Both plant and mammalian cells express glucuronosyltransferases that catalyze glucuronidation of polyphenols such as flavonoids and other small molecules. Oral administration of select polyphenolic compounds leads to the accumulation of the corresponding glucuronidated metabolites at μM and sub-μM concentrations in the brain, associated with amelioration of a range of neurological symptoms. Determining the mechanisms whereby botanical extracts impact cognitive wellbeing and psychological resiliency will require investigation of the modes of action of the brain-targeted metabolites. Unfortunately, many of these compounds are not commercially available. This article describes the latest approaches for the analysis and synthesis of glucuronidated flavonoids. Synthetic schemes include both standard organic synthesis, semisynthesis, enzymatic synthesis and use of synthetic biology utilizing heterologous enzymes in microbial platform organisms.

  19. Nanometric solid solutions of the fluorite and perovskite type crystal structures: Synthesis and properties

    Directory of Open Access Journals (Sweden)

    Snežana Bošković

    2012-09-01

    Full Text Available In this paper a short review of our results on the synthesis of nanosized CeO2, CaMnO3 and BaCeO3 solid solutions are presented. The nanopowders were prepared by two innovative methods: self propagating room temperature synthesis (SPRT and modified glycine/nitrate procedure (MGNP. Different types of solid solutions with rare earth dopants in concentrations ranging from 0–0.25 mol% were synthesized. The reactions forming solid solutions were studied. In addition, the characteristics of prepared nanopowders, phenomena during sintering and the properties of sintered samples are discussed.

  20. Anionic polymerization of acrylates. Synthesis of (meth)acrylate di- and triblock copolymers using the Li ester-enolate/tert-alkoxide initiating system

    Czech Academy of Sciences Publication Activity Database

    Vlček, Petr; Otoupalová, Jaroslava; Janata, Miroslav; Látalová, Petra; Kurková, Dana; Toman, Luděk; Masař, Bohumil

    2004-01-01

    Roč. 37, č. 2 (2004), s. 344-351 ISSN 0024-9297 R&D Projects: GA ČR GA203/01/0513; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : ligated anionic polymerization * block copolymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.898, year: 2004

  1. Synthesis of silver nanoparticles by chemical reduction at various fraction of MSA and their structure characterization

    Energy Technology Data Exchange (ETDEWEB)

    Diantoro, Markus, E-mail: m-diantoror@yahoo.com; Fitrianingsih, Rina, E-mail: m-diantoror@yahoo.com; Mufti, Nandang, E-mail: m-diantoror@yahoo.com; Fuad, Abdulloh, E-mail: m-diantoror@yahoo.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang (UM), Jl. Semarang No. 5 Malang 65145 (Indonesia)

    2014-03-24

    Nanosilver is currently one of the most common engineered nanomaterials and is used in many applications that lead to the release of silver nanoparticles and silver ions into aqueous systems. Nanosilver also possesses enhanced antimicrobial activity and bioavailability that may less environmental risk compared with other manufactured nanomaterials. Described in this research are the synthesis of silver nanoparticle produced by chemical reduction from silver nitrate (AgNO{sub 3}) solution. As a reducing agent, Sodium Borohydride (NaBH{sub 4}) was used and mercaptosuccinic Acid (MSA) as stabilizer to prevent the nanoparticle from aglomerating. It was also used two kinds of solvent, they are water and methanol. In typical experiment MSA was dissolve in methanol with a number of variation of molarity i.e. 0,03 M, 0,06 M, 0,12 M, 0,15 M, and the mixture was kept under vigorous stirring in an ice bath. A solution of silver nitrate of 340 mg in 6,792 ml water was added. A freshly prepared aqueous solution of sodium borohydride (756,6 mL in 100 mL of water) was added drop wisely. The solution was kept for half an hour for stirring and were allowed to settle down in methanol. The obtained samples then characterized by means of x-ray diffractometer, and scanning electron microscopy, as well as transmission electron microscopy to obtain their structures of silver nanoparticles, morphology, and sizes. It is shown that diameter of silver nanoparticle sized about 24.3 nm (Ag@MSA 0.03 M), 20.4 nm (Ag@MSA 0.06 M), 16.8 nm (Ag@MSA 0.12 M), 16.9 nm (Ag@MSA 0.15 M) which was calculated by Scherrer formula by taking the FWHM from fitting to Gaussian. The phases and lattice parameter showed that there is no significant change in its volume by increasing molarity of stabilizer. In contrast, the size of particles is decreasing.

  2. Synthesis, structure combined with conformational analysis, biological activities and docking studies of bis benzylidene cyclohexanone derivatives

    Directory of Open Access Journals (Sweden)

    Gehad Lotfy

    2017-07-01

    Full Text Available We report the synthesis and biological evaluation of bis benzylidne cyclohexanone derivatives 2,6-di(4-fluorobenzylidenecyclohexanone 3a and (2E,6E‐2,6‐bis({[4‐(trifluoromethylphenyl]methylidene}cyclohexanone 3b. Compound 3b crystallized in the monoclinic space group P21/n with unit cell parameters a = 29.3527(12 Å, b = 8.3147(3 Å, c = 32.7452(14 Å, β = 112.437(2°, and V = 7386.8(5 Å3, Z = 16, and Rint = 0.072 at T = 100 K. The asymmetric unit contains four independent molecules, each of which has slight differences in the bond lengths and angles. One non-classical C11D–H11F⋯F3A hydrogen bond connects the molecules. Density functional theory was used to optimize the structures and calculate the natural charges, dipole moments, frontier molecular orbitals, and NMR and UV–Vis spectroscopic properties, which are discussed and compared with the experimental data. The synthetic derivatives were evaluated for α-glucosidase inhibitory activity, and we found that compound 3a (IC50 = 96.3 ± 0.51 μM is a potent α-glucosidase inhibitor, showing superior activity to the standard drug acarbose (IC50 = 841 ± 1.73 μM. Compound 3b (IC50 = 7.92 ± 1.3 μg/mL was found to be a potent antileishmanial compound, especially compared to the antileishmanial drugs pentamidine (IC50 = 5.09 ± 0.04 μM and amphotericine B (IC50 = 0.29 ± 0.05 μg/mL. In addition, 3a and 3b have cytotoxic effects against PC3 (prostate cancer, HeLa (cervical cancer, and MCF-3 (breast cancer cell lines. Docking study for compounds activity was performed with Openeye software in order to understanding their pose of interaction in the target receptors.

  3. One dimensional CuO nanocrystals synthesis by electrical explosion: A study on structural, optical and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Shutesh, E-mail: shutesh.k@onsemi.com [Department of Mechanical Engineering University of Malaya, 50603 Kuala Lumpur (Malaysia); ON Semiconductor Package Innovation and Development Center, 70450 Seremban (Malaysia); Haseeb, A.S.M.A.; Johan, Mohd Rafie [Department of Mechanical Engineering University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-02-15

    Highlights: • One-dimensional CuO nanoflakes were synthesized by novel wire explosion technique. • A physical synthesis method capable of producing high aspect ratio (1:16) nanocrystals. • Most energy efficient and eco-friendly synthesis of low-dimensional transition metal oxide nanocrystals. -- Abstract: One-dimensional (1D) copper oxide (CuO) nanocrystals were synthesized using a novel wire explosion in de-ionized (DI) water without any chemical additives. Highly crystalline 1D CuO nanocrystals with 1:16 aspect ratio were successfully synthesized using this technique. The chemical nature and physical structure of the nanocrystals were controlled by simply modulating the exploding medium temperature. The results showed that nanocrystals produced at explosion temperatures 65 °C and 95 °C are pure CuO with optical band-gap energy of 2.38 eV. High Resolution Transmission Electron Microscope analysis (HRTEM) indicates that the CuO nanocrystals are with growth in [1{sup ¯}11] and [1 1 1] directions. The epitaxial crystal growth kinetics of the 1D nanostructure by aggregation was discussed. The incorporation of microstructural features like edge dislocations and porosity in the growth mechanism was examined. X-ray photoelectron spectroscopy (XPS) characterization indicates the formation of high purity CuO nanocrystals with valence state +2. This study provides an energy efficient and eco-friendly synthesis method of 1D transition metal oxide nanocrystals for electronic applications.

  4. 6-Pyruvoyltetrahydropterin synthase orthologs of either a single or dual domain structure are responsible for tetrahydrobiopterin synthesis in bacteria.

    Science.gov (United States)

    Kong, Jin Sun; Kang, Ji-Youn; Kim, Hye Lim; Kwon, O-Seob; Lee, Kon Ho; Park, Young Shik

    2006-09-04

    6-Pyruvoyltetrahydropterin synthase (PTPS) catalyzes the second step of tetrahydrobiopterin (BH4) synthesis. We previously identified PTPS orthologs (bPTPS-Is) in bacteria which do not produce BH4. In this study we disrupted the gene encoding bPTPS-I in Synechococcus sp. PCC 7942, which produces BH4-glucoside. The mutant was normal in BH4-glucoside production, demonstrating that bPTPS-I does not participate in BH4 synthesis in vivo and bringing us a new PTPS ortholog (bPTPS-II) of a bimodular polypeptide. The recombinant Synechococcus bPTPS-II was assayed in vitro to show PTPS activity higher than human enzyme. Further computational analysis revealed the presence of mono and bimodular bPTPS-II orthologs mostly in green sulfur bacteria and cyanobacteria, respectively, which are well known for BH4-glycoside production. In summary we found new bacterial PTPS orthologs, having either a single or dual domain structure and being responsible for BH4 synthesis in vivo, thereby disclosing all the bacterial PTPS homologs.

  5. Synthesis and crystal structure of the quaternary compound AgFe{sub 2}GaTe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Gerzon E., E-mail: gerzon@ula.ve [Laboratorio de Cristalografía, Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101 (Venezuela, Bolivarian Republic of); Quintero, Eugenio; Tovar, Rafael; Grima-Gallardo, Pedro; Quintero, Miguel [Centro de Estudio de Semiconductores, Departamento de Física, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101 (Venezuela, Bolivarian Republic of)

    2014-11-15

    Highlights: • New quaternary compound. • Synthesis from solid state reaction. • Crystal structure. • Rietveld refinement. - Abstract: The crystal structure of the quaternary compound AgFe{sub 2}GaTe{sub 4}, belonging to the system I–II{sub 2}–III–VI{sub 4}, was characterized by Rietveld refinement using X-ray powder diffraction data. The powder pattern was composed by 84.5% of the principal phase AgFe{sub 2}GaTe{sub 4} and 15.5% of the secondary phase FeTe. This material crystallizes with stannite structure in the tetragonal space group I-42m (N° 121), Z = 2, unit cell parameters a = 6.3409(2) Å, c = 12.0233(4) Å, V = 483.42(3) Å{sup 3}, and is isostructural with CuFe{sub 2}InSe{sub 4}.

  6. Synthesis and characterization of alumina-coated aluminum sponges manufactured by sintering and dissolution process as possible structured reactors

    Energy Technology Data Exchange (ETDEWEB)

    Méndez, Franklin J., E-mail: fmendez@ivic.gob.ve [Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado Postal 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Rivero-Prince, Sayidh [Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado Postal 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Facultad de Ingeniería, Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of); Escalante, Yelisbeth; Villasana, Yanet [Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado Postal 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Brito, Joaquín L., E-mail: joabrito@ivic.gob.ve [Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado Postal 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of)

    2016-03-01

    Al{sub 2}O{sub 3}–Al sponges were manufactured by sintering and dissolution process with the aim of using these materials as structured catalytic reactors. For this purpose, several synthesis conditions were examined for the design of the cellular material, such as: particle size of NaCl, weight fraction of Al, compaction pressure, and sintering temperature or time. An alumina layers was grown on top of the aluminum surfaces during both: sintering and thermal treatment. The obtained results showed that the synthesized materials could be promising as structured reactors for endothermic or exothermic reactions. - Highlights: • An efficient method for manufactured of aluminum sponges is reported. • Methods for productions of superficial Al{sub 2}O{sub 3} are studied. • Al{sub 2}O{sub 3}–Al sponges could be used as structured reactors.

  7. Synthesis of CdS hollow/solid nanospheres and their chain-structures by membrane technique

    International Nuclear Information System (INIS)

    Duan Shumin; Wu Qingsheng; Jia Runping; Liu Xinbo

    2008-01-01

    CdS hollow/solid nanospheres and their chain-structures were successfully synthesized through supporting liquid membrane (SLM) system with bio-membrane. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy, and photoluminescence (PL) spectroscopy have been used for the characterization of the products. The average diameters of CdS solid/hollow spheres are about 10, 40 nm, respectively. The wall of the hollow spheres is about 5 nm. CdS products are all cubic face-centered structure with the cell constant a = 5.830 A. We also explore the morphology, structure and possible synthesis mechanism. A possible template mechanism has been proposed for the production of the hollow CdS nanocrystals, that is, CdS nanoparticles grow along the non-soakage interface between CHCl3 and reactant solution. During this process, the organic functional groups were crucial to the control of crystal morphologies

  8. Synthesis of Framework Isomer MOFs Containing Zinc and 4-Tetrazolyl Benzenecarboxylic Acid via a Structure Directing Solvothermal Approach

    Directory of Open Access Journals (Sweden)

    Carlos Ordonez

    2015-04-01

    Full Text Available The solvothermal synthesis of framework isomers was carried out using the hybrid carboxylate and tetrazolate functional ligand, 4-tetrazolyl benzenecarboxylic acid (H2TBC, TBC = 4-tetrazolyl benzenecarboxylate and zinc. H2TBC was also synthesized with the solvothermal approach, and is referred herein as structure 1. Using single-crystal X-ray diffraction, we found that the tetrazolate groups of TBC show an unusual “opposite-on” coordination mode with zinc. Three previously characterized metal-organic frameworks (MOFs were obtained by systematically changing the solvents of the H2TBC-Zn reaction, (1 ZnTBC, 2, which has a non-porous structure; (2 Zn2(TBC2(H2O, 3, which has an amphiphilic pore structure and (3 Zn2(TBC2{guest}, 4, which is porous and has channels containing uncoordinated N heteroatoms. Fluorescence spectra of 4 reveal a strong blue emission mainly from the TBC ligands.

  9. Synthesis and structure assignment of 2-(4-methoxybenzyl)cyclohexyl beta-D-galactopyranoside stereoisomers

    Czech Academy of Sciences Publication Activity Database

    Šaman, David; Wimmerová, Martina; Wimmer, Zdeněk

    2006-01-01

    Roč. 71, č. 8 (2006), s. 1186-1198 ISSN 0010-0765 R&D Projects: GA MŠk(CZ) OC D29.001 Institutional research plan: CEZ:AV0Z40550506 Keywords : Koenigs-Knorr synthesis * alkyl beta-D-galactopyranoside * juvenogens Subject RIV: CC - Organic Chemistry Impact factor: 0.881, year: 2006

  10. Synthesis and structural characterization of (C14H16N2)3 ...

    Indian Academy of Sciences (India)

    2. Experimental. 2.1 Materials and methods. Commercially available Molybdenum trioxide MoO3, tolidine C14H16N2, lithium perchlorate LiClO4, dimй- thylformamide sulfoxide DMSO, were used without further purification. Hydrothermal synthesis has been carried out using a 23 mL Teflon-lined autoclave. IR. 1769 ...

  11. Synthesis, electrochemical, structural and theoretical study of new derivatives of OABAN and OABAO heterocycles

    Czech Academy of Sciences Publication Activity Database

    Mikysek, T.; Kvapilová, Hana; Doušová, H.; Josefík, F.; Šimůnek, P.; Růžičková, Z.; Ludvík, Jiří

    2017-01-01

    Roč. 455, č. 2 (2017), s. 465-472 ISSN 0020-1693 R&D Projects: GA MŠk LD14129 Institutional support: RVO:61388955 Keywords : boron heterocycles * synthesis * electrochemistry Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 2.002, year: 2016

  12. Structure elucidation and stereoselective total synthesis of pavettamine, the causal agent of gousiekte

    CSIR Research Space (South Africa)

    Bode, ML

    2010-03-01

    Full Text Available data of the acetonide derivative. The absolute stereochemistry was established by total synthesis from (2S)-malic acid using chiral sulfoxide methodology as (2S,4R,8R,10S)-1,11-diamino-6-aza-undecane-2,4,8,10-tetraol....

  13. Synthesis and structure assignment of 2-(4-methoxybenzyl)cyclohexyl beta-D-glucopyranoside enentiomers

    Czech Academy of Sciences Publication Activity Database

    Šaman, David; Kratina, Pavel; Moravcová, J.; Wimmerová, Martina; Wimmer, Zdeněk

    2006-01-01

    Roč. 71, č. 10 (2006), s. 1470-1483 ISSN 0010-0765 R&D Projects: GA MŠk(CZ) OC D29.001 Institutional research plan: CEZ:AV0Z40550506 Keywords : Koenigs-Knorr synthesis * alkyl glukosid * enantiomer Subject RIV: CC - Organic Chemistry Impact factor: 0.881, year: 2006

  14. Lucifensin, a Novel Insect Defensin of Medicinal Maggots: Synthesis and Structural Study

    Czech Academy of Sciences Publication Activity Database

    Čeřovský, Václav; Slaninová, Jiřina; Fučík, Vladimír; Monincová, Lenka; Bednárová, Lucie; Maloň, Petr; Štokrová, Jitka

    2011-01-01

    Roč. 12, č. 9 (2011), s. 1352-1361 ISSN 1439-4227 R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptide * disulfide bridge * lucifensin * solid phase synthesis Subject RIV: CC - Organic Chemistry Impact factor: 3.944, year: 2011

  15. Palladium(II)-Stabilized Pyridine-2-Diazotates: Synthesis, Structural Characterization, and Cytotoxicity Studies.

    Science.gov (United States)

    Tskhovrebov, Alexander G; Vasileva, Anna A; Goddard, Richard; Riedel, Tina; Dyson, Paul J; Mikhaylov, Vladimir N; Serebryanskaya, Tatiyana V; Sorokoumov, Viktor N; Haukka, Matti

    2018-02-05

    Well-defined diazotates are scarce. Here we report the synthesis of unprecedented homoleptic palladium(II) diazotate complexes. The palladium(II)-mediated nitrosylation of 2-aminopyridines with NaNO 2 results in the formation of metal-stabilized diazotates, which were found to be cytotoxic to human ovarian cancer cells.

  16. Total Synthesis of (-)-Doliculide, Structure-Activity Relationship Studies and Its Binding to F-Actin

    NARCIS (Netherlands)

    Matcha, Kiran; Madduri, Ashoka V. R.; Roy, Sayantani; Ziegler, Slava; Waldmann, Herbert; Hirsch, Anna K. H.; Minnaard, Adriaan J.

    2012-01-01

    Actin, an abundant protein in most eukaryotic cells, is one of the targets in cancer research. Recently, a great deal of attention has been paid to the synthesis and function of actin-targeting compounds and their use as effective molecular probes in chemical biology. In this study, we have

  17. From mechanical loading to collagen synthesis, structural changes and function in human tendon

    DEFF Research Database (Denmark)

    Kjær, Michael; Langberg, Henning; Heinemeier, Katja

    2009-01-01

    The adaptive response of connective tissue to loading requires increased synthesis and turnover of matrix proteins, with special emphasis on collagen. Collagen formation and degradation in the tendon increases with both acute and chronic loading, and data suggest that a gender difference exists...

  18. Synthesis, structure-activity relationship, and pharmacological profile of analogs of the ASIC-3 inhibitor A-317567.

    Science.gov (United States)

    Kuduk, Scott D; Di Marco, Christina N; Bodmer-Narkevitch, Vera; Cook, Sean P; Cato, Matthew J; Jovanovska, Aneta; Urban, Mark O; Leitl, Michael; Sain, Nova; Liang, Annie; Spencer, Robert H; Kane, Stefanie A; Hartman, George D; Bilodeau, Mark T

    2010-01-20

    The synthesis, structure-activity relationship (SAR), and pharmacological evaluation of analogs of the acid-sensing ion channel (ASIC) inhibitor A-317567 are reported. It was found that the compound with an acetylenic linkage was the most potent ASIC-3 channel blocker. This compound reversed mechanical hypersensitivity in the rat iodoacetate model of osteoarthritis pain, although sedation was noted. Sedation was also observed in ASIC-3 knockout mice, questioning whether sedation and antinociception are mediated via a non-ASIC-3 specific mechanism.

  19. The synthesis and structure of new transition metal lithium calcium nitride compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hunting, Janet L., E-mail: jhunting@ithaca.edu [Department of Chemistry, Cornell University, Baker Laboratory, Ithaca, New York 14853 (United States); Department of Chemistry, Ithaca College, 953 Danby Road, Ithaca, New York 14850 (United States); Szymanski, Marta M. [Department of Chemistry, Cornell University, Baker Laboratory, Ithaca, New York 14853 (United States); Kowalsick, Amanda L. [Department of Chemistry, Ithaca College, 953 Danby Road, Ithaca, New York 14850 (United States); Downie, Craig M.; DiSalvo, Francis J. [Department of Chemistry, Cornell University, Baker Laboratory, Ithaca, New York 14853 (United States)

    2013-01-15

    Three new nitrides, Li{sub 3}Ca{sub 2}V{sub 0.79}Nb{sub 0.21}N{sub 4}, Li{sub 2}Ca{sub 2.67}Nb{sub 0.33}N{sub 3} and Li{sub 12}Ca{sub 9}W{sub 5}N{sub 20}, were synthesized in sealed niobium tubes using lithium nitride as a flux at temperatures ranging from 800 Degree-Sign C to 1050 Degree-Sign C. In all of these compounds, the transition metals are coordinated tetrahedrally by nitrogen; these tetrahedra are isolated from each other. Bullet Li{sub 3}Ca{sub 2}V{sub 0.79}Nb{sub 0.21}N{sub 4}, space group P2{sub 1}/m (no. 11), cell parameters a=5.7669(8) A, b=6.9123(9) A, c=6.0116(12) A, {beta}=90.727(9) Degree-Sign , Z=2, has a shared vanadium/niobium tetrahedral position which shares vertices with the tetrahedrally-coordinated lithium position. Bullet Li{sub 2}Ca{sub 2.67}Nb{sub 0.33}N{sub 3}, space group Req /o(3, Macron )m (no. 166), cell parameters a=3.6311(2) A, c=29.459(3) A, Z=3, contains a disordered tetrahedral calcium/niobium position, an octahedral calcium position and a triangularly coordinated lithium position. Bullet Li{sub 12}Ca{sub 9}W{sub 5}N{sub 20}, space group C2/c (no. 15), cell parameters a=27.7347(19) A, b=8.6652(6) A, c=10.7685(7) A, {beta}=110.314(2) Degree-Sign , Z=4, contains three crystallographically different tungsten positions as well as one disordered lithium position. - Graphical abstract: Crystal structure of Li{sub 3}Ca{sub 2}V{sub 0.79}Nb{sub 0.21}N{sub 4} depicting the chains of edge-sharing LiN{sub 4} (light hatching) and (V/Nb)N{sub 4} (dark hatching) tetrahedra viewed approximately along the [100] direction. Calcium atoms are shown as open circles and nitrogen atoms are colored black. Highlights: Black-Right-Pointing-Pointer Three new lithium calcium nitrides are synthesized. Black-Right-Pointing-Pointer Lithium nitride flux used in synthesis. Black-Right-Pointing-Pointer Structures contain isolated tetrahedrally coordinated transition metals. Black-Right-Pointing-Pointer Li{sub 12}Ca{sub 9}W{sub 5}N{sub 20} contains three

  20. Morphology, structure and optical properties of sol-gel ITO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stoica, T.F.; Teodorescu, V.S.; Blanchin, M.G.; Stoica, T.A.; Gartner, M.; Losurdo, M.; Zaharescu, M

    2003-08-15

    The alkoxidic route and the spinning deposition were used to prepare monolayer sol-gel indium tin oxide (ITO) films. The morphology and crystalline structure were investigated by cross-section transmission electron microscopy (XTEM) and atomic force microscopy (AFM). The ITO sol-gel mono-layer contains three regions of different porosities. The basic crystalline structure is that of the In{sub 2}O{sub 3} lattice. The optical properties have been studied by optical transmission and spectroscopic ellipsometry.