- Gel Systems for the Belousov-Zhabotinskii Reaction
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Gel systems and their advantages over an aqueous system for spatial patterns in the Belousov-Zhabotinskii reaction are investigated.Five new gel preparations are introduced in which several ferroin-type catalysts (highly hydrophobic and anionic) are immob
- Yamaguchi, T.,Kuhnert, L.,Nagy-Ungvarai, Zs.,Mueller, S. C.,Hess, B.
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- Evaluation of kinetic parameters for the thermal decomposition of γ-irradiated sodium bromate by dynamic thermogravimetry
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The thermal decomposition of γ-irradiated NaBrO3 was studied by dynamic thermogravimetry. The reaction order, activation energy, frequency factor and entropy of activation were computed using the Coats-Redfern, Freeman-Carroll and Horowitz-Metz
- Nair,Malayil, Koshy Kunju,Jacob, P.Daisamma
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- Biochar and kinetics studies on the reduction of sodium bromate by a cobaloxime in an aqueous media: How we can remove a toxic substance from our environment
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The reduction of sodium bromate (NaBrO3) by [Co(dmgBF2)2(OH2)2] (where dmgBF2 = difluoroboryldimethylglyoximato) was investigated in hydrochloric and nitric acids. Analytical studies were carried out via gravimetric analysis and UV–visible spectrophotometry. Gravimetric analysis proved that sodium bromate was reduced to from quantitative amounts of sodium bromide in the presence of hydrochloric acid. Biochar was used to sequester the complex from the reaction mixture and to neutralize the acidic media. The UV–visible data confirmed the sequestration of the complex from the reaction mixture after exposure to the biochar. The collected pH data proved a direct relationship between pH and the amount of biochar used in the form of a titration curve. Kinetic studies were also carried out to ascertain the mechanism of the oxidation of [Co(dmgBF2)2(OH2)2] by NaBrO3. The oxidation of [Co(dmgBF2)2(OH2)2] by NaBrO3 was carried out by stopped-flow spectrophotometry at 450 nm by varying temperature and over the range of 1.00 mM ≤ [HCl] ≤ 11.00 mM, at a constant ionic strength of 0.60 M (NaCl). From the data, a mechanism for the reaction was proposed. From the mechanism the following rate expression was derived, [Formula presented], where k1 was calculated to be 4.2 × 104 M?1 s?1 at 25 °C, and the activation parameters (ΔH? and ΔS?) were calculated as 57 ± 1 kJ mol?1 and 34 ± 4 J mol?1 K?1, respectively.
- Celestine, Michael J.,Holder, Alvin A.,Kumar, Sandeep,Nunez, Brianne S.,Tano, Criszcele M.,Tonsel-White, Elizabeth A.
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- Nitrogen-rich carbon nitride materials shock-synthesized from carbon tetrahalide and sodium dicyanoamide
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Shock reactions between CX4 (X=Br or I) and NaN(CN)2 were investigated to prepare carbon nitrides. The post shock samples were characterized by the powder X-ray diffraction (XRD) technique. The XRD spectrum of the product showed a peak in the range of 0.324-0.336?nm in d-value corresponding to the (002) basal plane diffraction in graphitic structure. Elemental analysis (C, H, N, O) of the product showed that the atomic ratio of nitrogen to carbon (N/C) ranged from 0.38 to 1.3. Analysis of data revealed that the d-value increased and the nitrogen content decreased with the increase of the impact velocity.
- Shibata, Kazusato,Sekine, Toshimori
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- Ion Exchange of Layered Alkali Titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with Alkali Halides by the Solid-State Reactions at Room Temperature
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Ion exchange of layered alkali titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with several alkali metal halides surprisingly proceeded in the solid-state at room temperature. The reaction was governed by thermodynamic parameters and was completed within a shorter time when the titanates with a smaller particle size were employed. On the other hand, the required time for the ion exchange was shorter in the cases of Cs2Ti5O11 than those of K2Ti4O9 irrespective of the particle size of the titanates, suggesting faster diffusion of the interlayer cation in the titanate with lower layer charge density.
- Ogawa, Makoto,Saothayanun, Taya Ko,Sirinakorn, Thipwipa Tip
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p. 4024 - 4029
(2020/04/08)
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- Nitryl cyanide, NCNO2
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The elusive nitryl cyanide, NCNO2, has been synthesized and characterized. It was prepared in good yield, isolated by fractional condensation, characterized by NMR and vibrational spectroscopy, and studied by theoretical calculations. Nitryl cyanide holds promise as a high energy density material (HEDM) and might also prove useful as a HEDM building block. The simplicity and inherent stability of nitryl cyanide, together with the known multitude of nitriles in interstellar space, suggest that the compound might also be a potential candidate for observations in atmospheric and interstellar chemistry. Small yet feisty: The elusive small molecule nitryl cyanide, NCNO2, has been synthesized and characterized. It has a high kinetic stability, is extremely energetic, has a perfect oxygen balance with respect to combustion to CO2 and N2, and has potential as a building block for other energetic materials. Nitryl cyanide might also be of interest for atmospheric and interstellar chemistry. Isp=specific impulse.
- Rahm, Martin,Belanger-Chabot, Guillaume,Haiges, Ralf,Christe, Karl O.
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supporting information
p. 6893 - 6897
(2014/07/08)
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- Synthesis, characterization, and catalytic behavior of methoxy- and dimethoxy-substituted pyridinium-type ionic liquids
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Synthesis of methoxy-substituted pyridinium-type ionic liquids from a nontoxic and easy method is described. Catalytic behaviors of synthesized ionic liquids were investigated with various concentrations for the Mannich reaction. We have observed that methoxy- and dimethoxy-substituted pyridinium bromides showed better catalytic behavior than other ionic liquids.
- Manikandan, Chitrarasu,Ganesan, Kilivelu
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p. 3362 - 3367
(2014/12/11)
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- PROCESS FOR THE PREPARATION OF CONCENTRATED SOLUTIONS OF STABILIZED HYPOBROMITES
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The invention is a process for the preparation of stabilized aqueous solutions of alkali hypobromites at low temperatures, which comprises reacting a concentrated alkali hydroxide aqueous solution with bromine, and adding to the reaction product, which is a non-stabilized solution, an aqueous solution of a sulfamic compound, such as sodium sulfamate, thus forming a stabilized alkali hypobromite solution.
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(2009/06/27)
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- METHODS FOR PRODUCING PERFLUOROALKANEDI(SULFONYL CHLORIDE)
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Novel methods for preparing perfluoroalkanedi(sulfonyl chloride) are disclosed as are uses for these compounds. In one aspect, a method comprising reacting dibromoperfluoroalkane with Na2S2O4 followed by treating with chlorine, an organic compound, and then chlorine to form perfluoroalkanedi(sulfonyl chloride) is provided. Novel perfluoroalkanedi(sulfonyl bromide) compounds are also disclosed.
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Page/Page column 9
(2009/05/29)
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- Alkyl-terminated crystalline Ge nanoparticles prepared from NaGe: Synthesis, functionalization and optical properties
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High purity NaGe was directly prepared by a low-temperature reaction of NaH and Ge. The product was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. This material is a useful starting reagent for the preparation of Ge nanoparticles. Hydrogen-terminated germanium (Ge) nanoparticles were prepared by reaction of NaGe with NH4Br. These Ge nanoparticles could be prepared as amorphous or crystalline nanoparticles in quantitative yields and with a narrow size distribution. The nanoparticles were functionalized via thermally initiated hydrogermylation with 1-eicosyne, CH3(CH2)17C≡CH to produce alkyl-terminated Ge nanoparticles. The modified Ge nanoparticles were characterized by powder XRD, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and Raman spectroscopy, and photoluminescence (PL) spectroscopy. The alkyl-functionalized Ge nanoparticles can be expected to have promising applications in many technological and biological areas.
- Ma, Xuchu,Wu, Fengyi,Kauzlarich, Susan M.
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p. 1628 - 1633
(2009/02/02)
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- PROCESS FOR THE RECOVERY OF MATERIALS FROM A DESULFURIZATION REACTION
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Disclosed herein is an improved method for regenerating materials from a desulfurization/demetallation reaction. The desulfurization/demetallation reaction preferably has products including one or more of an alkali sulfide, polysulfide or hydrosulfide, or alkali earth sulfide, polysulfide, or hydrosulfide. The method includes the steps of reacting the desulfurization/demetallation products with a halogen, liberating and removing sulfur from the product, and then electrolyzing the halogenated products to separate the halogen from the alkali metal or alkali earth metal.
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(2010/02/13)
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- PREPARATION OF CONCENTRATED BROMINE SOLUTIONS AND HIGH ACTIVITY BROMINE SOLIDS
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The invention includes convenient methods of preparing: (1) highly concentrated liquid bromine-containing biocidal solutions, (2) highly concentrated mixed halogen liquid bromine and chlorine-containing biocidal solutions, and (3) high-activity bromine containing biocidal solids, all having excellent physical and chemical stability. One method yields solutions that have concentrations of bromine in excess of 18% as Br2 (8% as C12) in which the mole ratio of hydroxide ion to hydrogen ion source is at least 1.9: 1. Another method employs elemental bromine in conjunction with a solid organic or inorganic halogenating agent to yield halogen solutions at concentrations greater than 22.9% as Br2 (10.2% as C12). This method can be performed under conditions that exceed the solubility of the active ingredient such that it crystallizes and is recovered as a hydrated or anhydrous salt in good yield.
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Page/Page column 23-24; 31-32; 40-41
(2008/06/13)
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- Methods for the preparation of concentrated aqueous bromine solutions and high activity bromine-containing solids
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The invention includes convenient methods of preparing: (1) highly concentrated liquid bromine-containing biocidal solutions, (2) highly concentrated mixed halogen liquid bromine and chlorine-containing biocidal solutions, and (3) high-activity bromine-containing biocidal solids, all having excellent physical and chemical stability. One method yields solutions that have concentrations of bromine in excess of 18% as Br2 (8% as Cl2) in which the mole ratio of hydroxide ion to hydrogen ion source is at least 1.9:1. Another method employs elemental bromine in conjunction with a solid organic or inorganic halogenating agent to yield halogen solutions at concentrations greater than 22.9% as Br2 (10.2% as Cl2). This method can be performed under conditions that exceed the solubility of the active ingredient such that it crystallizes and is recovered as a hydrated or anhydrous salt in good yield.
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Page/Page column 7; 10; 12
(2008/06/13)
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- Cathepsin cysteine protease inhibitors
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This invention relates to a novel class of compounds which are cysteine protease inhibitors, including but not limited to, inhibitors of Cathepsins K and L. These compounds are useful for treating diseases in which inhibition of bone resorption is indicated, such as osteoporosis.
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- Bromite ion catalysis of the disproportionation of chlorine dioxide with nucleophile assistance of electron-transfer reactions between ClO2 and BrO2 in basic solution
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The rate of ClO2 conversion to ClO2- and ClO3- is accelerated by BrO2-, repressed by ClO2-, and greatly assisted by many nucleophiles (Br- > PO43- > HPO42- > CO32- > Cl- ~ OH- > CH3COO- ~ SO42- C5H5N ? H2O). The kinetics (at p[H+] = 9.3-12.9) show that the first step of the mechanism is an electron transfer between ClO2 and BrO2- (k1 = 36 M-1 s-1) to give ClO2- and BrO2. This highly reversible reaction (k1/k-1 = 1 × 10-6) accounts for the observed inhibition by ClO2-. The second step is an electron transfer between ClO2 and BrO2 to regenerate BrO2- and form ClO3-. A novel aspect of the second step is the large kinetic contribution from nucleophiles (kNu) that assist the electron transfer between ClO2 and BrO2. The kNu (M-2 s-1) values at 25.0 °C vary from 2.89 × 108 for Br- to 2.0 × 104 for H2O.
- Wang, Lu,Nicoson, Jeffrey S.,Huff Hartz, Kara E.,Francisco, Joseph S.,Margerum, Dale W.
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p. 108 - 113
(2008/10/08)
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- The thermodynamic properties of CoCl2-NaBr and CoCl2-KBr melts
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Boiling temperatures were measured at different pressures for CoCl2-NaBr and CoCl2-KBr melts of various compositions by the method of boiling points under isobaric conditions. The experimental data were described by the equation log p = B - A/T. Dependences with negative deviations from the Raoult law were obtained. The thermodynamic properties of the melts were calculated.
- Kritskaya,Burylev,Moisov,Kostenko
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p. 911 - 914
(2007/10/03)
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- Synthesis and thermolysis of tris(triethoxysiloxy)aluminum and its complexes with potassium and sodium triethoxysilanolates
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Reaction of potassium (or sodium) triethoxysilanolate with AlBr 3 in benzene in a 3:1 or 4:1 ratio yields, respectively, tris(triethoxysiloxy)aluminum Al[OSi(OEt)3]3 or potassium (or sodium) tetrakis(triethoxysiloxy)alumin
- Shcherbakov,Basova,Khorshev,Malysheva,Domrachev
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p. 394 - 397
(2007/10/03)
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- Observation of Na223Πg-13Σ +u bound-free emissions generated from Na(3p) in a reactive oxidation process
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The chemiluminescent reaction products of the (Na,Na2)+Br halogenation system at concentrations in excess of 1012 cm-3 are considered. In a purely reaction driven environment evidence is obtained for the formation of the Na2 23Πg excited state and bound-free emission associated with the 23Πg-13Σu+ band system.
- Grantier,Gole
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p. 417 - 422
(2008/10/08)
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- Synthesis and characterization of novel octahedral cobalt(III) complexes
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The novel octahedral cobalt(III) complexes [Co(HL)BrL′]ClO4 have been prepared by the reaction of (E,E)-3,9-dimethyl-5,7-di-oxa-4,8-diaza-3,8-undecadiene-2,10-dione dioxime (H2L) and CoBr2.6H2O. The complexes of H2L have a metal : ligand ratio of 1:1 and the ligand coordinates through the N atoms, as in most oximes, with axial ligation by substitued pyridines (L′) and bromide ion. The cobalt complexes have been characterized by 1H NMR, IR, MS spectral and elemental analysis data.
- Karaboecek, Nevin,Goek, Yasar
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p. 1723 - 1731
(2008/10/09)
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- Thermochemistry of the NaBr-NaI solid solution at 750 K - A knudsen effusion mass spectrometric study
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The excess molar Gibbs energy and partial pressures at a temperature of 750 K for the solid phase of the NaBr-Nal system were determined by Knudsen effusion mass spectrometry. The parameters of the Redlich-Kister equation for GmE resulted in kJ mol-1 as B1=6.46 and B2=-1.12. The thermodynamic data obtained from the molecular ion intensities of NaBr+ and NaI+ and those obtained from the fragment ion intensities of Na2Br+ (from Na2Br2) and Na2I+ (from Na2I2) agree well. The results of this work are discussed with respect to those reported by other authors. WILEY-VCH Verlag GmbH, 1998.
- Miller, Miroslaw,Hilpert, Klaus
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p. 1370 - 1375
(2008/10/08)
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- Studies on Synthetic and Structural Aspects of Unsymmetrical Tetraorganoarsonium and stibonium Halides, Pseudohalides and Carboxylates : Electrophilic Cleavage of M-Allyl Bond
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Triphenylarsine and triphenylstibine react with allyl bromide to give the corresponding allyltriphenylarsonium and stibonium laclides. The metal-allyl bond is readily cleaved by electrophiles, such as Br2, I2, ICI and IBr. Metathetical reactions involving allyltriphenytarsonium and stibonium halides and the appropriate metal salts, M'X(M' = Na, K, Ag; X = NCS, NCO, N3, CH3COCO, CCl3COO, C6H5COO) have been employed to yield a series of new compounds. The compounds are monomeric in beazine solution and 1 : 1 electrolyte in nitromethane.
- Singh Raizada, Meenu,Srivastava
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p. 646 - 649
(2008/10/09)
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- Reactions of Ground-State and Electronically Excited Sodium Atoms with Methyl Bromide and Molecular Chlorine
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The reactions of ground- and excited-state Na atoms with methyl bromide (CH3Br) and chlorine (Cl2) have been studied by using the crossed molecular beams method.For both reactions, the cross sections increase with increasing electronic energy.The product
- Weiss, P. S.,Mestdagh, J. M.,Schmidt, H.,Covinsky, M. H.,Lee, Y. T.
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p. 3005 - 3011
(2007/10/02)
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- Syntheses of dinuclear carbonylates of the iron subgroup: [M2(CO)8]2- (M = Ru, Os) and [FeRu(CO)8]2-. Structures of [PPh4]2[FeRu(CO)8]·CH3CN and [PPh4]2[Fe2(CO)8]·2CH 3CN
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The homonuclear dianions [Ru2(CO)8]2- and [Os2(CO)8]2-are prepared by a procedure that involves the reductive disproportionation of CO2 in its reaction with an alkali-metal salt of [M(CO)4]2- (M = Ru, Os) to form M(CO)5, which then reacts with additional [M(CO)4]2- in situ to give [M2(CO)8]2-. The dianion [FeRu(CO)8]2- is prepared by a procedure with two distinct steps: (1) [Ru(CO)4]2- reacts with CO2 in a 1:2 molar ratio to form Ru(CO)5; (2) [Fe(CO)4]2- is then added to the system, and it reacts with Ru(CO)5 to form [FeRu(CO)8]2-. The dinuclear dianions are isolated as the tetraphenylphosphonium salts. They are air- and moisture-sensitive. From a single-crystal X-ray analysis, the structure of [PPh4]2[FeRu(CO)8]·CH3CN has been determined. The dianion [FeRu(CO)8]2- has a structure which closely resembles that of [Ru2(CO)8]2-; however, there is disorder at the metal atom sites. The structure consists of a trigonal-bipyramidal fragment, M(CO)4 (M = 0.78 Ru, 0.22 Fe), bound at an equatorial site to a four-sided-pyramidal fragment, M′(CO)4 (M′ = 0.78 Fe, 0.22 Ru), bound at a basal site. For the purpose of comparing dianion structures with a common countercation, the structure of [PPh4]2[Fe2(CO)8]·2CH 3CN has been determined from a single-crystal X-ray analysis. The structure of [Fe2(CO)8]2- is in agreement with that previously obtained by Bau from [(Ph3P)2N]2[Fe2(CO) 8]·CH3CN. It consists of two Fe(CO)4 units, trigonal-bipyramidal fragments joined at apical sites in a staggered configuration. Crystal data for [PPh4]2[FeRu(CO)8]·CH3CN: space group Cc, monoclinic, a = 19.233 (3) A?, b = 16.535 (3) A?, c = 16.251 (4) A?, β = 98.81 (2)°, V = 5107 A?3, mol wt 1100.8, ρcalcd = 1.416 g cm-3 for Z = 4. μ = 6.8 cm-1 for Mo Kα. A total of 4646 unique reflections were collected at -50°C over the range 4 ≤ 2θ ≤ 50° with 3359 reflections ≥2σ(I) used in the final refinement. RF = 0.049 and RwF = 0.047. Crystal data for [PPh4][Fe2(CO)8]·CH3CN: space group P1, triclinic, a = 9.389 (3) A?, b = 12.086 (6) A?, c = 12.931 (11) A?, α = 71.37 (4)°, β = 76.75 (4)°, γ = 69.83°, V = 1293.4 A?3, mol wt 1096.6, ρcalcd = 1.351 g cm-3 for Z = 1. μ = 6.7 cm-1 for Mo Kα. A total of 4534 unique reflections were collected at -50°C over the range 4 ≤ 2θ ≤ 50° with 3168 reflections ≥3σ(I) used in the final refinement. RF = 0.030 and RwF = 0.044.
- Bhattacharyya, Nripendra K.,Coffy, Tim J.,Quintana, William,Salupo, Terese A.,Bricker, Jeffery C.,Shay, Timothy B.,Payne, Martin,Shore, Sheldon G.
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p. 2368 - 2374
(2008/10/08)
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- Benzyltitanium and -zirconium cobalt carbonyls. Preparation and spectroscopic characterization
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Tetrabenzyltitanium (1a) and -zirconium (1b) react with equimolar HCo(CO)4 (2) to give the corresponding tribenzylmetal-cobalt tetracarbonyl (M = Ti, 5a; M = Zr, 5b) derivatives. Compounds 5 also can be obtained from (PhCH2)3/s
- Bartik, Tamás,Happ, Berit,Sorkau, Angela,Thiele, Karl-Heinz,Pályi, Gyula
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p. 558 - 560
(2008/10/08)
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- Influence of π-donation on N-methyl group exchange in zirconocene N,N-dimethyldithiocarbamates and N,N-dimethylthiocarbamates
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The kinetics of N-methyl group exchange in zirconocene N,N-dimethyldithiocarbamates, Cp2ZrX(Me2dtc) (X = Cl, Br, I, Me, CH2SiMe3, CH2CMe2Ph, CH2Ph, OPh, Opy (4-hydroxypyridinate), OXyl (2,6-dimethylphenoxide)), and N,N-dimethylthiocarbamates, Cp2ZrX(Me2mtc) (X = Cl, Opy), have been studied by variable-temperature 1H NMR spectroscopy. For the Cp2ZrX(Me2dtc) complexes, rates and activation parameters are relatively independent of the nature of the monodentate ligand when X = halide or alkyl (k(25°C) = 1-25 s-1; ΔH? = 14-17 kcal/mol), but there is a dramatic increase in rate as the π-donating ability of X varies in the order Cl 4 s-1 and ΔH? = 9.8 kcal/mol when X = OPh. No dramatic increase in exchange rate is observed for Cp2ZrX(Me2mtc) as X varies from Cl to Opy. Except for the aryloxy dithiocarbamate complexes, rates and activation parameters are similar to those for related organic dithiocarbamates and thiocarbamates, strongly suggesting a mechanism involving rotation about the C=N bond. Cp2ZrX(Me2dtc) (X = OPh, Opy) is believed to exchange methyl groups by a Zr-S bond-rupture mechanism. This mechanism, which is promoted by the π-donor properties of the aryloxy ligands, is inaccessible in aryloxythiocarbamate complexes because it would give a higher energy, unobserved stereoisomer. Preparative methods for the Cp2ZrX(Me2dtc) and Cp2ZrX(Me2mtc) complexes and the Cp2Zr(X)Cl intermediates are described.
- Femec, Douglas A.,Silver, Michael E.,Fay, Robert C.
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p. 2789 - 2796
(2008/10/08)
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- Thermal reactions of CdCl2 and CdBr2 in NaNO3-KNO3 eutectic melt
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CdCl2 and CdBr2 dissolve in NaNO3-KNO3 eutectic melt.When these melts are heated, cadmium halides undergo decomposition reaction, CdBr2 reacting with a faster rate as compared with CdCl2.The two reactions obey second order kinetics.In the case of CdCl2 eutectic system, CdO, NaCl, KCl, NO2 and O2 are obtained as the end products.However, in the case of CdBr2-eutectic system, CdO, NaBr, KBr, Br2, NO2 and O2 are obtained as the reaction products.The kinetics of the reactions have been followed by isothermal thermogravimetry and the solid residues identified by X-ray diffraction technique.The gaseous products have been analysed in the usual manner.Mechanisms of reactions have been explored by DTA technique also.
- Singh, N. B.,Kumar, P.,Pandey, S.P.
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p. 645 - 648
(2007/10/02)
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- Sodium atom Reactions with the Bromochloromethanes: Branching Ratios and Relative Reaction Rates
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Branching ratios into bromide and chloride products have been measured for the reaction of atomic sodium with BrCCl3, BrCHCl2 and BrCH2Cl.The bromide to chloride product ratios are 0.55, 1.83, and 4.00, respectively.The experiments were performed in a lin
- Jayne, J. T.,Davidovits, P.
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p. 3574 - 3579
(2007/10/02)
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- Gas-Phase Dimerization of Sodium Halides and Formation of Mixed Sodium/Phenyl Iodides
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The formation of dimers and oligomers of the monomeric sodium halides NaCl, NaBr and NaI were studied in a flow reactor at a pressure of 300 Pa and temperature of 623 and 645 K.The reactions propynyl chloride/bromide + Na vapour were used to generate the gaseous NaCl and NaBr while the sodium iodide monomer was formed via the reaction Na + CH3I.The rate constants for the dimerizations of NaCl, NaBr and NaI were found to be 8.0E13, 5.0E13 and 5.0E12 cm3*mol-1*s-1, respectively.Under the experimental conditions the dimerizations were near their high-pressure limits.NaCl oligomers up to 5 were detected while the detection of NaBr oligomers was limited by the accessible mass range to 3. - In the system Na + Phenyliodide (PhI) mixed Na/Phenyliodides were formed but hardly any NaI.Disodium-phenyliodide was a main product.Higher compounds such as Na3Ph2I and Na3PhI2 were also detected in lower concentrations.In addition, diphenyl was a product of a homogeneous reaction while benzene was formed both by a heterogeneous and a homogeneous reaction.The reaction mechanism is discussed on the basis of an intermediate complex Na + PhI --> NaPhI. - Keywords: Chemical Kinetics / Elementary Reactions / Mass Spectrometry / Radicals
- Alkemade, U.,Homann, K. H.
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p. 434 - 439
(2007/10/02)
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- REACTION OF SALTS OF HYPOPHOSPHOROUS ACID WITH ALKYLHALIDES
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Alkali salts of hypophosphorous acid undergo an exchange reaction with alkyl halides.From the interaction between potassium hypophosphite and allyl bromide or 3-chloro-1,2-propanediol phosphonous acids are formed.A mechanism of the interaction, a variant of the Michaelis-Becker reaction, is proposed.
- Devedjiev, I.,Ganev, V.,Stefanova, R.,Borissov, G.
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p. 261 - 266
(2007/10/02)
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- Synthesis of hexacarbonyl derivatives of group 5 metals and electron-transfer processes. Crystal and molecular structure of tetracarbonyl(1,2-bis(diphenylphosphino)ethane)iodotantalum
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Vanadium, niobium, and tantalum hexacarbonylmetalate(-I) derivatives of several heterocyclic nitrogen bases, RnB[M(CO)6]n (R = H, Me; n = 1, 2), have been synthesized. In some cases an electron transfer from the hexacarbonylmetalate to the protonated or methylated BRnn+ cation has been observed. Pyridinium halides react with Na[M(CO)6] (M = Nb, Ta) in the presence of 1 equiv of 1,2-bis(diphenylphosphino)ethane (diphos) to give high yields of the halo tetracarbonyl derivatives MX(CO)4(diphos). The red-orange TaI(CO)4(diphos) complex has been studied by X-ray diffraction methods. Crystal data: space group P21/n; Mr 818.3; a = 14.864 (10) ?, b = 9.875 (7) ?, c = 19.335 (13) ?; β = 105.61 (2)°; U = 2733 (3) ?3; Z = 4; Dcalcd = 1.988 g cm-3; F(000) = 1568; μ(Mo Kα) = 52.4 cm-1. The geometry of the seven-coordinate tantalum atom is best described as a capped trigonal prism with the iodide ligand in the capping position. By reaction of Na[Ta(CO)6] with 1 equiv of hydrogen chloride and diphos in toluene, the hydride TaH(CO)4(diphos) has been isolated in good yield.
- Calderazzo, Fausto,Pampaloni, Guido,Pelizzi, Giancarlo,Vitali, Francesca
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p. 1083 - 1092
(2008/10/08)
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- Coordination compounds containing a novel tridentate pyrazolylgallate ligand. X-ray structures of Me2Ga(μ-OH)(μ-Me2pz)GaMe2.HOCH2Me2pz and 2Ni (pz=N2C3H3)
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The syntheses of the novel anionic tridentate dimethyl(pyrazol-1-y1)(1-oxymethylpyrazolyl)gallate ligand and representative transition metal complexes thereof are reported.The direct reaction of Me3Ga with 1-hydroxymrthyl-3,5-dimethylpyrazole leads to the isolation of Me2Ga(μ-OH)(μ-Me2pz)GaMe2.HOCH2Me2pz.Crystals of (μ-hydroxy)(μ-3,5-dimethylpyrazolyl)bis(dimethylgallium) 1-hydroxymethyl-3,5-dimethylpyrazole solvate are monoclinic, a=33.105(2), b=7.3048(7) c=8.8336(6) Angstroem, β=97.474(7) deg, Z=4, space group P21/n, and those of bis2,N2',O>nickel(II) are monoclinic, a=9.6345(3), b=14.2731(6), c=18.6356(7) Angstroem, β=99.660(3) deg, Z=4, space group P21/c.Both structures were solved by conventional heavy atom methods and were refined by full-matrix least-squares procedures to R=0.044 and 0.037 for 2660 and 3904 reflections with I>/=3?(I), respectively.Mean bond lengths in Me2Ga(μ-OH)(μ-Me2pz)GaMe2.HOCH2Me2pz are Ga-O = 1.918(11), Ga-N = 2.001(5), and Ga-C = 1.955(5) Angstroem.Fac-2Ni crystallizes as an all-cis isomer with normal bond lengths and angles at Ga and Ni-O = 1.918(3) and 1.927(3), Ni-N = 2.030(4) Angstroem.The coordination geometry about Ni is irregular pseudo-octahedral with evidence of both steric and structural trans effects.
- Mar, Arthur,Rettig, Steven J.,Storr, Alan,Trotter, James
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p. 101 - 108
(2007/10/02)
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- Reactions of Pentafluorophenyl(ylide)-silver(I) or-gold(I) complexes with Chlorobis(pentafluorophenyl)thallium(III)
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Chlorobis(pentafluorophenyl)tallium(III) reacts with silver-ylide complexes (ER3 = PPh3, PPh2Me, PPhMe2, or AsPh3) to give AgCl and , whereas the reactions with gold-ylide complexes, , lead to gold(III0 complexes of the types trans- and which have been isolated and characterized.
- Uson, Rafael,Laguna, Antonio,Laguna, Mariano,Uson, Alfredo,Gimeno, M. Concepcion
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p. 701 - 704
(2007/10/02)
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- Synthesis and photochemical behavior of μ-p-xylene-α,α'-diyldimolybdenum(II) complex
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Reaction of Na (cp = η5-cyclopentadienyl) with α,α'-dibromo-p-xylene afforded 2(μ-CH2C6H4CH2-p)> which reacts with PMe2Ph to give a mono-acyl, and then finally a bis-acyl complex.Photolysis of the μ-p-xylene-α,α'-diyl complex induces homolytic cleavage of the Mo-C bond to produce radical intermediates, which are converted, via p-quinodimethane, to p-xylene and its polymers.
- Isobe, Kiyoshi,Tero-Kubota, Shozo,Tanaka, Hisao,Nakamura, Yukio,Okeya, Seichi,Saito, Kazuo
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p. C21 - C24
(2007/10/02)
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- Addition compounds of alkali metal hydrides. 22. Convenient procedures for the preparation of lithium borohydride from sodium borohydride and borane-dimethyl sulfide in simple ether solvents
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The preparation of LiBH4 in various ether solvents from the readily available reagents NaBH4 and lithium halides is described. The reactivity of lithium halides toward the metathesis reaction generally follows the order LiBr > LiI > LiCl. The heterogeneous reactions proceed satisfactorily with vigorous magnetic stirring. However, attempting to increase the scale of the preparations utilizing mechanical stirrers resulted in incomplete reactions and decreased yield. On the other hand, when the heterogeneous mixture was stirred with mechanical stirrers fitted with Teflon paddles and a mass of glass beads, the rate of the reaction increased considerably, producing quantitative yields of LiBH4 in greatly decreased reaction times. The ease of conversion of NaBH4 into LiBH4 in various solvents follows the order isopropylamine > 1,3-dioxolane > monoglyme > tetrahydrofuran ≈ ether. The isolation of solvent-free LiBH4 from the various solvates was attempted under different conditions. In most cases, normal distillation at 100 or 150°C produced a strong 1:1 solvate, LiBH4·solvent. Only in the case of ethyl ether is the solvent of solvation readily removed at 100°C at atmospheric pressure. In the other cases, both higher temperatures, up to 150°C, and lower pressures, down to 0.1 mm, are required to produce the unsolvated material. Thus the ease of isolating unsolvated LiBH4 is ethyl ether > IPA > THF > 1,3-D ≈ MG. Consequently, ethyl ether is the medium of choice for the preparation of LiBH4 by the metathesis of NaBH4 and LiBr. LiBH4 can also be conveniently prepared by the reaction of LiH with H3B·SMe2 in ethyl ether. Dimethyl sulfide is readily removed, along with ethyl ether of solvation, at 100°C (atmospheric pressure). These procedures make LiBH4 readily available.
- Brown, Herbert C.,Choi, Yong Moon,Narasimhan
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p. 3657 - 3661
(2008/10/08)
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