- Static observation of the interphase between NaBH4 and LiI during the conversion reaction
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To determine the synthesis conditions for NaI–NaBH4–LiI solid solutions in a single phase, the conversion reaction of NaBH4 ?+ ?LiI → NaI ?+ ?LiBH4 was investigated by preparing mixed pellets of NaBH4/LiI. The extent of the reaction was investigated under different reaction temperatures and pressures. Although it was not possible to completely suppress the conversion reaction in this study, the low temperature and high-pressure conditions were shown to be favorable to avoid the presence of LiBH4. A significant point is that the conversion reaction was investigated in a static condition in the form of pellets, whereas most of the metal borohydride-halide composites have been fabricated by ball-milling. The microstructure of NaBH4/LiI mixed pellets at different ageing times was observed by scanning electron microscope (SEM), Auger electron spectroscopy (AES), wavelength dispersive X-ray spectroscopy (WDS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The analysis revealed that the reaction interphase between NaBH4 and LiI occurs in the order of LiI/NaI/LiBH4/NaBH4. It was clearly confirmed that the growth of the NaI layer continued with time even at room temperature. In conjunction with the array of the interphase, the diffusion of Na+ in LiBH4 appears to be a necessary condition for the growth of the NaI layer. The present results suggest that a detailed investigation of the conversion reaction between other metal borohydrides and halides (for example, CeCl3/LiBH4, ZrCl4/KBH4, etc.) in the static condition would likely reveal the diffusion of the new ions in the existing compounds.
- Hihara, Takehiko,Miyagawa, Reina,Miyazaki, Reona,Onishi, Keita
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- Crystal and Electronic Structures of A2NaIO6Periodate Double Perovskites (A = Sr, Ca, Ba): Candidate Wasteforms for I-129 Immobilization
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The synthesis, structure, and thermal stability of the periodate double perovskites A2NaIO6 (A= Ba, Sr, Ca) were investigated in the context of potential application for the immobilization of radioiodine. A combination of X-ray diffraction and neutron diffraction, Raman spectroscopy, and DFT simulations were applied to determine accurate crystal structures of these compounds and understand their relative stability. The compounds were found to exhibit rock-salt ordering of Na and I on the perovskite B-site; Ba2NaIO6 was found to adopt the Fm-3m aristotype structure, whereas Sr2NaIO6 and Ca2NaIO6 adopt the P21/n hettotype structure, characterized by cooperative octahedral tilting. DFT simulations determined the Fm-3m and P21/n structures of Ba2NaIO6 to be energetically degenerate at room temperature, whereas diffraction and spectroscopy data evidence only the presence of the Fm-3m phase at room temperature, which may imply an incipient phase transition for this compound. The periodate double perovskites were found to exhibit remarkable thermal stability, with Ba2NaIO6 only decomposing above 1050 °C in air, which is apparently the highest recorded decomposition temperature so far recorded for any iodine bearing compound. As such, these compounds offer some potential for application in the immobilization of iodine-129, from nuclear fuel reprocessing, with an iodine incorporation rate of 25-40 wt%. The synthesis of these compounds, elaborated here, is also compatible with both current conventional and future advanced processes for iodine recovery from the dissolver off-gas.
- Dixon Wilkins, Malin C.,George, Jonathan,Hyatt, Neil C.,Kim, Eunja,Kirk, Cameron,Knight, Kevin S.,Montoya, Eduardo,O'Sullivan, Sarah E.,Sun, Shi-Kuan,Weck, Philippe F.
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p. 18407 - 18419
(2020/12/23)
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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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- Multistep soft chemistry method for valence reduction in transition metal oxides with triangular (CdI2-type) layers
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Transition metal (M) oxides with MO2 triangular layers demonstrate a variety of physical properties depending on the metal oxidation states. In the known compounds, metal oxidation states are limited to either 3+ or mixed-valent 3+/4+. A multistep soft chemistry synthetic route for novel phases with M2+/3+O2 triangular layers is reported.
- Blakely, Colin K.,Bruno, Shaun R.,Poltavets, Viktor V.
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supporting information
p. 2797 - 2800
(2014/03/21)
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- Origin of the thermal desorption peaks of gases in NaI above 180°C
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We analyze the origin of the water desorption peaks in NaI above the temperature stability range of the crystalline hydrate NaI ? 2H 2O. The two water desorption peaks at t ≥ 180°C are shown to arise from the decomposition of aqua complexes bas
- Sofronov,Kudin,Voloshko, A. Yu.,Kudin,Shishkin
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p. 1314 - 1318
(2010/03/25)
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- Chemical synthesis of aluminum nitride nanorods in an autoclave at 200 °C
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Hexagonal phase aluminum nitride (AlN) nanorods have been prepared via a chemical reaction from Al, I2, and NaN3 in an autoclave at 200°C. Electron microscopy investigations show that the nanorods have diameters ranging from 50 to 100nm and lengths up to several micrometers. Thermal gravimetric analysis reveals that the sample has good thermal stability below 600°C, and room-temperature photoluminescence (PL) of the sample shows a strong emission peak centered at 397 nm. Copyright
- Fu, Li,Xu, Liqiang,Duan, Junling,Li, Ting,Yang, Lishan,Qian, Yitai
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p. 622 - 623
(2011/04/21)
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- METHODS FOR SYNTHESIZING AMMONIA BORANE
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Methods of synthesizing ammonia borane are provided. The methods comprise reacting at least one amine borane with ammonia such that ammonia borane is produced. Ammonia borane has a chemical formula Of NH3-BH3 and provides a good source of storage hydrogen making it useful in a variety of applications including a potential hydrogen source for fuel cells. The methods can further comprise separating the ammonia borane from the other products of the reaction. Exemplary methods can produce ammonia borane having purity greater than about 90 percent. In further examples, the methods can produce ammonia borane having purity greater than about 95 percent or greater than about 99 percent.
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Page/Page column 4; 11; 6
(2008/06/13)
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- Sm2O2I - A new mixed-valence samarium(II,III) oxide halide
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Dark red single crystals of Sm2O2I were obtained from a reaction of SmI2 (in the presence of SmOI) and Na in a sealed tantalum ampoule at 650 °C. The title compound crystallizes in the monoclinic system (C2/m, Z = 4, a = 12.639(2), b = 4.100(1), c = 9.762(3) A, β = 117.97(2)°). The structure consists of corrugated [Sm 2+Sm3+(O2-)2]+ layers of edge and vertex-connected Sm4O tetrahedral units with I- anions separating the layers.
- Ryazanov, Mikhail,Hoch, Constantin,Mattausch, Hansjuergen,Simon, Arndt
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p. 2385 - 2388
(2008/10/09)
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- New synthesis route to and physical properties of lanthanum monoiodide
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A fast procedure to produce Lal by reduction of Lal2 or Lal 3 in a Na melt under argon at 550°C is given. The structural studies performed by means of powder X-ray diffraction as well as transmission electron microscopy are consistent with previous single-crystal results. Measurements of the electrical resistance on polycrystalline samples reveal metallic behavior for Lal in the range 10-300 K. Upon cooling, a small maximum in the resistivity has been observed at 67 K. This anomaly disappears upon heating a sample, however, yielding a hysteresis in ρ(T) above 70 K. From the Pauli susceptibility, an electron density of states at the Fermi level of about 0.3 eV-1·formula unit-1 has been estimated, as compared with a value of 1.0 eV-1·formula unit-1 derived from ab initio LMTO band structure calculations.
- Ryazanov, Mikhail,Kienle, Lorenz,Simon, Arndt,Mattausch, Hansjuergen
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p. 2068 - 2074
(2008/10/09)
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- The synthesis of a sterically hindered samarium(II) bis(amidinate) and conversion to its homoleptic trivalent congener
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The first divalent samarium bis(amidinate) has been prepared and aspects of its novel chemistry, including the preparation of a sterically hindered homoleptic Sm(III) tris(amidinate), explored. The Royal Society of Chemistry 2005.
- Cole, Marcus L.,Junk, Peter C.
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p. 2695 - 2697
(2007/10/03)
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- Reactions of sodium hydroxide with sodium iodide, iodate, and periodate
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Sodium iodide forms adducts with sodium hydroxide of the NaI·2NaOH (mp 225-230°C) and NaI·3NaOH (mp 215-220°C) compositions. Sodium iodate in the presence of NaOH disproportionates to iodide and orthoperiodate according to the reaction NaIO3 + 3NaOH → 1/4NaI + 3/4Na5IO 6 + 3/2H2O. The process begins at ~270°C and ends at ~420°C (melting of NaIO3). In the presence of NaOH, sodium meta-periodate NaIO4 decomposes (as in the pure state) at 290°C to NaIO3 and O2, but with the formation of ~5% Na 5IO6.
- Nikitina,Nikitina
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p. 945 - 947
(2008/10/08)
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- Synthesis and structures of magnesium alanate and two solvent adducts
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A synthesis and purification method for Mg(AlH4)2 is presented, which is based on a metathesis reaction of NaAlH4 and MgCl2 in diethyl ether and subsequent purification procedure leading to a high yield of the monoether adduct of Mg(AlH4)2. After removal of the solvent, the alanate has been obtained as a nanocrystalline material with a yield of 81% and a purity of 95%. Crystal structures were determined and discussed for the solvent adducts Mg(AlH4)2·4THF and Mg(AlH4)2·Et2O. A proposition is made for the structure of Mg(AlH4)2. Elsevier Science B.V. All rights reserved.
- Fichtner, Maximilian,Fuhr, Olaf
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p. 286 - 296
(2008/10/08)
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- Improved synthetic routes to layered NaxCoO2 oxides
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Improved synthetic routes to four NaxCoO2 (0.52 ≤ x ≤ 1) oxides of varying compositions and structures are presented. A combination of ceramic techniques and oxidative deintercalation reactions were used to access this series. Comparisons are made to previously reported preparative methods and differences in unit cell parameters discussed.
- Cushing, Brian L.,Wiley, John B.
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p. 1199 - 1207
(2008/10/09)
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- Strained Metallastannoxanes-Ring-Opening Polymerization versus Retention of Six-Membered-Ring Structure
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The synthesis is reported of the novel stannasiloxanes cyclo-M(OSiPh2)2O (1, M = Sn[(CH2)3NMe2]2; 2, M = Sn[(CH2)3N(Me)CH2]2; 4, M = Sn[Cp(CO)2Fe]2; 5, M = Sn[Cp-(CO)3W]2; 6, M = Sn(t-Bu)[Cp(CO)3W]) and cyclo-(Ph2SiOSnR2O)2 (3, R = (CH2)3NMe2), and of the stannagermoxane cycfo-t-Bu2Sn(OGePh2)2O (7). The molecular structures are described of 1-4, 6, and 7. The compounds exhibit reduced ring strain as a result of either intramolecular Sn-N coordination (1, 2) or electronic influence of the transition-metal fragments (4-6), and consequently they are six-membered rings in solution as well as in the solid state, whereas compound 3 is an eight-membered ring.
- Beckmann, Jens,Jurkschat, Klaus,Kaltenbrunner, Ulrich,Pieper, Nicole,Schürmann, Markus
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p. 1586 - 1595
(2008/10/08)
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- Synthesis of LiI-NaI-ScI3 Additive for Metal Halide Lamps
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A component for filling metal halide lamps was prepared by reacting metallic lithium and iodine in the presence of a homogeneous mixture of anhydrous NaI and ScI3. The use of this material allowed rejects to be reduced by 12-15%.
- Safonov,Podorozhnyi
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p. 1147 - 1148
(2008/10/08)
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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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- Homoallyl-substituted vinylcyclopropanes from α,β-unsaturated ketones and allylindium derivatives
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Simply reversing the order of addition of aqueous acid and Et2O to the Barbier intermediate 1 of the known indium-mediated allylation leads to unprecedented deoxygenative rearrangements [Eq. (a)].
- Hoeppe, Henning A.,Lloyd-Jones, Guy C.,Murray, Martin,Peakman, Torren M.,Walsh, Kenneth E.
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p. 1545 - 1547
(2007/10/03)
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- X-ray structure, EPR, and magnetic susceptibility of gallium(III) tris(3,5-di-tert-butyl-1,2-semibenzoquinonate), a main group triradical complex
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The compound Ga(TBSQ?)3 (TBSQ? = 3,5-di-tert-butyl-1,2-benzosemiquinonate anion) has been prepared by two synthetic routes and its structure determined by X-ray analysis. The crystals are rhombohedral, with a = 16.408(6) ?, c = 13.898(4) ?, V = 3240(2) ?3, Z = 3, and space group R3(h); R = 0.050; T = 23°C. The molecule has a distorted octahedral GaO6 kernel, with bidentate TBSQ?- ligands. The compound and its solutions in noncoordinating solvents are stable for months, even when exposed to air. Frozen solution EPR spectra display evidence for the thermal occupation of both quartet, S = 3/2, and doublet, S = 1/2, states. A triradical should have both states, and comparison of theoretical simulations of the triradical EPR spectrum with the experimental spectrum reveals that the energy separation of the quartet and two doublet states is greater than 0.8 cm-1 and less than 20 cm-1. Ga(TBSQ?)3 reacts with pyridine to give Ga(TBSQ?)(TBC)(py)2 (TBC = 3,5-di-tert-butylcatecholate dianion). Magnetic susceptibility was measured for solid Ga(TBSQ?)3 from 2 to 296 K and for the toluene solution at 296 K. The low-temperature susceptibilities show that the ground state is the doublet states of the triradical, and the high-temperature susceptibilities can only be explained by postulating another thermally accessible doublet state, which is close in energy to the triradical states. This state is postulated to be Ga(TBSQ?)(TBC)(TBQ) (TBQ = 3,5-di-tert-butyl-1,2-benzoquinone).
- Ozarowski, Andrzej,McGarvey, Bruce R.,El-Hadad, Ahmed,Tian, Zhigang,Tuck, Dennis G.,Krovich, Daniel J.,DeFotis, Gary C.
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p. 841 - 847
(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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- 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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- 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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- Medication for pain relief in joints of humans
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A medication for the treatment and relief from pain of the joints of humans is provided said medication consisting of a compound comprised of iodine, sodium iodine, potassium iodine, alcohol and lemon extract.
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- Reactions of boron hydrides with the iminium salt [Me2NCH2]I. Synthesis and characterization of 1-X-μ-(Me2NCH2)B5H7 (X = H, C2H5, Br), a new class of bridge-substituted pentaborane derivatives
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Reactions of [Me2NCH2]I (1) with salts of the B5H8-, 1-(C2H5)B5H7-, and 1-BrB5H7- anions produce the μ-((dimethylamino)methyl)pentaborane derivatives μ-(Me2NCH2)B5H8, 1-(C2H5)-μ-(Me2NCH2)B 5H7, and 1-Br-μ-(Me2NCH2)B5H7, respectively, in good yields. A structure for these compounds is proposed in which a bridging hydrogen atom of B5H9 has been replaced by a C-N two-atom bridge, the Me2NCH2 group. These clusters are analogues of the arachno-B5H10- anion, and there is no evidence of direct bonding between the Me2NCH2-bridged boron atoms. Reaction of 1 with NaBH4 forms Me3N·BH3, while reaction with [Me4N][B3H8] produces a variety of products including Me3N·BH3, Me3N·B3H7, B2H6, and B5H9. Attack of 1 on B5H9 occurs slowly at 65°C, forming Me3N·BH3 and Me3N·B3H7.
- Gaines, Donald F.,Coons, Darrell E.
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p. 364 - 367
(2008/10/08)
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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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