- A lanthanide-gallium complex stabilized by the N-heterocyclic carbene group
-
The complex [Nd(L′){Ga(NArCH)2}(N″)(THF)], which exhibits the first f-element-gallium bond, is formed from the reaction between the N-heterocyclic carbene-supported neodymium complex [Nd(L′)(N″)(I)] (L′ = ButNCH2CH2{C(NCSiMe3 CHNBut)}; N″ = N(SiMe3)2) and the anionic gallium(I) heterocycle [Ga(NArCH)2][K(tmeda)] (Ar = 2,6-Pri2C6H3). The Nd-Ga bond energy is calculated to be 386 kJ mol-1. Copyright
- Arnold, Polly L.,Liddle, Stephen T.,McMaster, Jonathan,Jones, Cameron,Mills, David P.
-
-
Read Online
- ELECTROLYTIC RECOVERY OF GALLIUM FROM DILUTE SOLUTIONS EMPLOYING MICROELECTRODES.
-
The recovery of gallium from dilute solutions is known to be slow and inefficient due to competing hydrogen evolution and the limitations of mass transport. Methods used to improve the process include pulse plating, inhibition of hydrogen evoluation by su
- Paciej,Cahen Jr.,Stoner,Gileadi
-
-
Read Online
- Bis-NHC Aluminium and Gallium Dihydride Cations [(NHC)2EH2]+ (E = Al, Ga)
-
The NHC alane and gallane adducts (NHC)·AlH2I (NHC = Me2ImMe 7, iPr2Im 8, iPr2ImMe 9) and (NHC)·GaH2I (NHC = Me2ImMe 10, iPr2ImMe 11,
- Hock, Andreas,Werner, Luis,Riethmann, Melanie,Radius, Udo
-
-
Read Online
- Kinetics and mechanism of thermal decomposition of GaN
-
A scheme of dissociative evaporation of GaN with the partial evolution of nitrogen in the form of free atoms has been invoked to interpret the decomposition mechanism of GaN in vacuum or inert gas atmosphere. A critical analysis of literature data and their comparison with theoretical calculations has shown that the main kinetic characteristics of decomposition, including the absolute decomposition rate and activation energy are in full agreement with the reaction: GaN(s) → Ga(g)+0.5N+0.25N2. Condensation of the gallium vapor in the reaction zone and partial transport of condensation energy to GaN account for the features which are typical of many solid-state reactions and manifest themselves in the appearance of induction and acceleration periods in the course of the process. The low temperature decomposition of GaN in H2 according to the equilibrium reaction GaN(s)+ 1.5H2=Ga(g)+NH3 is supported by a good agreement of experimental and calculated activation energies and by the strong inhibition effect of NH3 on the GaN decomposition. As expected, condensation of Ga vapor in the Ga(l)/GaN(s) interface accelerates the reduction of GaN by H2 several hundred times. (C) 2000 Elsevier Science B.V.
- L'vov
-
-
Read Online
- Mono- and digallane complexes of a tridentate amido-diamine ligand
-
Bis(2-dimethylaminoethyl)amido gallane, H2GaN(CH 2CH2-NMe2)2, that melts at 27 °C and remains stable upon heating at 55 °C for two days, was synthesized either from the reaction of the quinuclidine adduct of monochlorogallane with the lithium salt of the corresponding amine, or from the reaction of trimethylamine gallane and the amine; the latter affords an unusual co-product with both GaH2 and GaH3 bonded to the same amido nitrogen. The Royal Society of Chemistry 2005.
- Luo, Bing,Kucera, Benjamin E.,Gladfelter, Wayne L.
-
-
Read Online
- Gallane complexes with amido-amine ligands
-
Gallane complexes bearing amido-amine ligands -N(R)CH2CMe2CH2NMe2 [R = H or SiMe3 (TMS)], {H2Ga-[N(H)CH2CMe2CH2 NMe2]}2, 1, H2/s
- Luo,Pink,Gladfelter
-
-
Read Online
- Sonochemical hydrolysis of Ga3+ ions: Synthesis of scroll-like cylindrical nanoparticles of gallium oxide hydroxide
-
The sonochemical reaction of an aqueous solution of GaCl3 led to the formation of gallium oxide hydroxide rolled up in a scroll-like layered structure to give cylinders 80-120 nm in diameter and 500-600 nm in length. Small amounts of metallic Ga were incorporated with these tubes. A mechanism for this reaction has been suggested where the reaction takes place in a shell surrounding the collapsing bubble.
- Avivi,Mastai,Hodes,Gedanken
-
-
Read Online
- In situ STM studies of Ga electrodeposition from GaCl3 in the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide
-
In the present paper the electrodeposition of Ga on Au(1 1 1) from 0.5 mol L-1 GaCl3 in the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide, [Py1,4]TFSA, has been investig
- Gasparotto,Borisenko,H?fft,Al-Salman,Maus-Friedrichs,Bocchi,Zein El Abedin,Endres
-
-
Read Online
- Electrodeposited gallium alloy thin films synthesized by solid state reactions for CIGS solar cell
-
The solid-state reactions of electroplated gallium thin films with copper, gold and molybdenum were investigated using XRD, SIMS, TEMEDS and linear strip voltammetry. Due to the low melting temperature of gallium metal, the activation energy for gallium diffusion is lower than the other metals used. Hence Ga diffuses faster and reacts to form alloy phases with the other metals investigated. In a thin film stack of Ga with another metals (Me), (Me = Cu, Au and Mo), equilibrium compounds are formed, which compounds form depends on the relative composition and diffusion time. If there is excess Ga, or excess Me, it can further react with the metastable compounds to form an equilibrium compound. In addition, TaN was found to act as an effective barrier layer to gallium diffusion.
- Ahmed,Reuter,Huang,Deligianni,Romankiw,Jaime,Grand
-
-
Read Online
- Determination of lanthanides (La, Ce, Nd, Sm) and other elements in metallic gallium by instrumental neutron activation analysis
-
This paper reports the analytical results of lanthanides and other elements in pure elemental gallium. The analyses were performed by instrumental neutron activation analysis (INAA) at the nuclear reactor IEA-R1, IPEN, S?o Paulo. INAA has the advantage of being a multi-elemental and non-destructive analytical method. After irradiation, the samples were set aside for some days before running high resolution gamma spectrometry with a hyper-pure Ge detector. Gallium was recovered from the Bayer process alkaline leach solution, named by local aluminum industry as 'weak soda', (spent liquor) with a concentration of about 150 mg l-1. As a first step, gallium was recovered from the 'weak soda' and enriched using a complexing ion-exchanger of the polyamidoxime type specially synthesized in the country for this purpose. After washing the column with water and then with pure sodium hydroxide to remove the interstitial 'spent liquor', gallium was eluted from the resin. The eluted gallium solution was made to 4 mol l-1 in NaOH and subject to electrolysis. The metal was then collected from the electrodes and given a final purification step by dilute inorganic acid stripping. The most representative lanthanide elements found and analyzed in the metallic gallium were La, Ce, Nd and Sm. One of the most recent samples exhibited the following results: (μg g-1) La (16.1), Ce (15.5), Nd (11.8) and Sm (3.6). Besides the lanthanides, the following elements were also analyzed: U, Cr, Fe, Co, Zn, Mo, Se, Sb and Ba. The results showed that the metal obtained is highly pure. The purity can be enhanced by stripping the metallic gallium with a dilute mineral acid.
- Figueiredo,Avristcher,Masini,Diniz,Abr?o
-
-
Read Online
- Low-pressure Photochemical Vapour Deposition of Gallium Metal from an Iodide Precursor
-
A study has been carried out of the low-pressure photochemical vapour deposition of gallium thin films from a gallium triiodide vapour stream, as a function of temperature, precursor partial pressure and illumination intensity.Deposition was found to take place through the photodissociation of adsorbed GaI molecules derived from the thermal decomposition of the triiodide.The reaction system was essentially oxygen-free, as shown by negligible dark deposition rates over the experimental temperature range of 673-873 K.The deposition rate was modelled using thermodynamic d ata in conjunction with the deBoer and B.E.T. adsorption theories.The resulting gallium films, which oxidized ex situ on exposure to the atmosphere, were characterised by ellipsometry, profilometry measurements of thickness, and EDX analysis for film composition.The possible growth of GaAs by this method was investigated by introducing molecular arsenic or arsenic triiodide into the system.The negligible incorporation of arsenic into the film, even at high arsenic partial pressures, is consistent with the presence of a stable GaI monolayer covering the gallium surface; this layer is taken to inhibit the formation of GaAs.Film growth was found to be consistent with photodeposition from a submonolayer of GaI adsorbed onto the iodine monolayer covering the gallium surface.The deposition of other Group IIIb metals by this method should be practical.
- Lane, Stephen J.,Green, Mino
-
-
Read Online
- Monochlorogallane: Synthesis, Properties, and Structure of the Dimer H2Ga(μ-Cl)2GaH2 in the Gas Phase as determined by Electron Diffraction
-
Monochlorogallane, synthesised by methathesis involving gallium(III) chloride and thrimethylsilane, has been characterised by its spectroscopic and chemical properties; electron diffraction has established the structure of the dimer H2Ga(μ-Cl)2GaH2, the p
- Goode, Michael J.,Downs, Anthony J.,Pulham, Colin R.,Rankin, David W. H.,Robertson, Heather E.
-
-
Read Online
- On the chemistry of gallium: Part 19. Synthesis and crystal structure analysis of novel complexes containing Ga-FeCp(CO)2-fragments
-
The gallium subhalides Ga2Cl4·2dioxane and sonochemically prepared GaI were reacted with the carbonyl ferrate K[Cp(CO)2Fe] and the iron carbonyl dimer [Cp(CO)2Fe]2, respectively. In all the reactions
- Linti, Gerald,Li, Guangming,Pritzkow, Heinz
-
-
Read Online
- Catalytic deoxygenation of benzaldehyde over gallium-modified ZSM-5 zeolite
-
The deoxygenation of benzaldehyde has been investigated over gallium-modified ZSM-5 catalysts. In the absence of H2, Ga/HZSM-5 catalyzes benzaldehyde decarbonylation resulting in benzene and CO. The active sites for this reaction are the strong
- Ausavasukhi, Artit,Sooknoi, Tawan,Resasco, Daniel E.
-
-
Read Online
- On the preparation of calcium gallohydride
-
The reaction of CsGaH4 or RbGaH4 with CaI2 in THF produced calcium gallohydride CaHGaH4 ? THF (I). DTA showed that compound I decomposes with an endotherm in the range 116-130°C. CaHGaH4 ? THF is well soluble in diglyme. In the IR spectrum of compound I, there is a strong band at 1780 cm-1, which is intrinsic to the Ga-H stretching vibrations.
- Bakum,Kuznetsova
-
-
Read Online
- Reactions of Gallium Hydrides with 1,4-Di-t-butyl-1,4-diazabutadiene: Subvalent and Hydrometallation Products
-
Reaction of LiGaH4 and gallium metal with 1,4-di-t-butyl-1,4-diazabutadiene (dbdab) in diethyl ether at room temperature yields the monomeric, formally gallium(II) species , (1), previously prepared using metal vapours, and GaH3*NMe3 with dbda
- Henderson, Mark J.,Kennard, Colin H. L.,Raston, Colin L.,Smith, Graham
-
-
Read Online
- New very shy intermetallic compound: AgGa
-
A new, intermetallic compound AgGa (with B2 structure) was found by differential thermal analysis and X-ray diffraction. It is stable below 305°C but decomposes peritectically very quickly under pressure above 26°C, producing a gallium-rich liquid phase and the Hume-Rothery Ag3Ga compound (26-32 at.%GA).
- Feschotte,Bass
-
-
Read Online
- Reactions of a gallium(ll)-diazabutadiene dimer, [(([(H)C(BU t)N]2)GaI)2], with [MESiMe3J 2] (M = Li or Na; e = N, P, or As): Structural, EPR, and ENDOR characterization of paramagnetic gallium(lll) pnictide complexes
-
The reactions of the paramagnetic gallium(ll) complex [((Bu t-DAB)Gal)2] (But-DAB = {(Bu tNC(H)}2) with the alkali metal pnictides [ME(SiMe 3)2] (M = Li or Na; E = N, P, or As) have been carried out under a range of stoichiometries. The 1:2 reactions have led to a series of paramagnetic gallium(III)-pnictide complexes, [(But-DAB) Ga{E(SiMe3)2}I] (E = N, P, or As), while two of the 1:4 reactions afforded [(But-DAB)Ga{ E(SiMe3) 2}2] (E = P or As). In contrast, treatment of [{(Bu t-DAB)Gal)2] with 4 equiv of [NaN(SiMe3) 2} resulted in a novel gallium heterocycle coupling reaction and the formation of the diradical species [(But-DAB)Ga{N(SiMe 3)2){[CC(H)N2(But) 2]Ga[N(SiMe3J2]CH3)]. The mechanism of this unusual reaction has been explored, and evidence suggests it involves an intramolecular transmethylation reaction. The X-ray crystal structures of all prepared complexes are reported, and all have been characterized by EPR and ENDOR spectroscopies. The observed spin Hamiltonian parameters provide a detailed picture of the distribution of the unpaired spin density over the molecular frameworks of the complexes.
- Antcllff, Karen L.,Baker, Robert J.,Jones, Cameron,Murphy, Damien M.,Rose, Richard P.
-
-
Read Online
- Hydrogallation of alkynes: Syntheses of carbon-gallium cages possessing heteroadamantane structures
-
A study was performed on hydrogallation of alkynes. The synthesis of carbon-gallium cages processing heteroadamantane structures was reported. The heteroadamantane-type compounds (GaR)6(CR′)4 were formed in which the positions of the methylene bridges of the carbon skeleton in adamantane were occupied by coordinatively unsaturated, tricoordinate gallium atoms.
- Uhl, Werner,Cuypers, Lars,Neumüller, Bernhard,Weller, Frank
-
-
Read Online
- Ga9(CMe3)9, an important new building block in the structural chemistry of the alkylelement(I) compounds EnRn (E = B - In)
-
A simple preparative method has been employed for the synthesis of the novel cluster compound Ga9 (CMe3)9, which contains a tricapped trigonal prism of monovalent gallium atoms. Electron transfer processes, were observed similar to those of polyboranes, leading to the reversible formation of the corresponding radical anion.
- Uhl, Werner,Cuypers, Lars,Harms, Klaus,Kaim, Wolfgang,Wanner, Matthias,Winter, Rainer,Koch, Rainer,Saak, Wolfgang
-
-
Read Online
- Optical characteristics of GaInP/GaP double-heterostructure core-shell nanowires embedded in polydimethylsiloxane membranes
-
The authors report on the optical properties of GaInP/GaP double-heterostructure (DH) core-shell nanowires (NWs) embedded in polydimethylsiloxane (PDMS) membranes. Self-catalyzed NW structures are grown on Si (111) substrates by initiating with the formation of Ga droplets as a catalyst which is followed by the growth of GaP core and GaInP DH shells. Optical characteristics of GaInP/GaP DH core-shell NWs transferred from Si substrates into PDMS membranes show enhanced 77 K light emission at 630 nm. The signal at 775 nm from the surface states of NWs can be mitigated by embedding the NWs in a PDMS membrane that acts as a surface state passivant.
- Tatebayashi,Mariani,Lin,Hicks,Huffaker
-
-
Read Online
- Synthesis and catalytic properties of nanoparticulate intermetallic Ga-Pd compounds
-
A two-step synthesis for the preparation of single-phase and nanoparticulate GaPd and GaPd2 by coreduction of ionic metal-precursors with LiHBEt3 in THF without additional stabilizers is described. The coreduction leads initially to the formation of Pd nanoparticles followed by a Pd-mediated reduction of Ga3+ on their surfaces, requiring an additional annealing step. The majority of the intermetallic particles have diameters of 3 and 7 nm for GaPd and GaPd 2, respectively, and unexpected narrow size distributions as determined by disk centrifuge measurements. The nanoparticles have been characterized by XRD, TEM, and chemical analysis to ensure the formation of the intermetallic compounds. Unsupported nanoparticles possess high catalytic activity while maintaining the excellent selectivity of the ground bulk materials in the semihydrogenation of acetylene. The activity could be further increased by depositing the particles on α-Al2O3.
- Armbruester, Marc,Wowsnick, Gregor,Friedrich, Matthias,Heggen, Marc,Cardoso-Gil, Raul
-
-
Read Online
- Synthesis and structures of gallium amido imido phenyl clusters (PhGa)4(NHiBu)4(NiBu)2 and (PhGa)7(NHME)4(NMe)5
-
The phenylgallium-containing clusters constructed with bridging imido and amido ligands, (PhGa)4(NHiBu)4(NiBu)2 (1) (51% yield) and (PhGa)7(NHMe)4(NMe)5 (2) (31% yield), were synthesized from the room-temperature reactions of bis(dimethylamido)phenylgallium, [PhGa(NMe2)2]2, with isobutylamine and methylamine, respectively. The reaction of [PhGa(NMe2)2]2 in refluxing isobutylamine (85°C) afforded (Ph2GaNHiBu)2 as one of the products, while the reaction of [PhGa(NMe2)2]2 with methylamine at 150°C afforded compound 2 in only 9% yield. Compound 1 possessed an admantane-like Ga4N6 core, whereas compound 2 had a novel Ga7N9 core constructed with both chair- and boat-shaped Ga3N3 rings. The presence of several isomers of compounds 1 and 2 in solution is discussed along the structural similarities with other known gallium-nitrogen clusters and with gallium nitride.
- Luo, Bing,Gladfelter, Wayne L.
-
-
Read Online
- Unexpected formation of gallium-gallium single bonds by irradiation of the hydride [(Me3C)2GaH]3
-
Di(tert-butyl)gallium hydride 1 dismutates partially in solution forming tri(tert-butyl)gallium 2 and the sesquihydride [(Me3C)2GaH]2[H2GaCMe 3]2 (3). The loss of tert-butyl radicals upon irradiation of this mixture with day light or an UV lamp gave the hexagallium compound (Me3CGaGaCMe3)2(μ-H)2[μ-H 2Ga(CMe3)2]2 (4), which possesses two Ga-Ga single bonds. These Ga2 groups are bridged by two hydrogen atoms to give a six-membered Ga4H2 heterocycle. Couples of opposite gallium atoms of this heterocycle are bridged via Ga-H-Ga 3c-2e bonds by two H2Ga(CMe3)2 ligands, which are situated above and below the molecular plane. Compound 4 may be described as a hypho-hexagallane(14) cluster compound.
- Uhl, Werner,Cuypers, Lars,Geiseler, Gertraud,Harms, Klaus,Neumueller, Bernhard
-
-
Read Online
- Chemistry of C-trimethylsilyl-substituted heterocarboranes. 22. Synthetic, spectroscopic, structural, and bonding studies on half- and full-sandwich gallacarboranes of 2,3- and 2,4-C2B4 carborane ligand systems
-
The reaction of the TMEDA-solvated group 1 salts of the carborane dianions [2,n-(SiMe3)2-2,n-C2B4H 4]2- (n = 3, 4) with GaC13 in a 2:1 carborane-to-GaCl3 molar ratio gave the corresponding full-sandwich gallacarboranes [2,2′,n,n′-(SiMe3) 4-1,1′-commo-Ga(1,2,n-GaC2B4H 4)2]- (n = 3 (I), 4 (II)) in 36% and 38% yields, respectively. Lowering the carboraneto-GaCl3 molar ratio to 1:1 produced the half-sandwich chlorogallacarboranes 1-(TMEDA)-1-Cl-2,n-(SiMe3)2-1,2,n-GaC2B 4H4 (n = 3 (III), 4 (IV)) in 51% and 41% yields, respectively. Compounds I-IV were characterized on the basis of1H, 11B, and 13C NMR spectra, IR spectra, and single-crystal X-ray analyses. The structures of the gallacarboranes show that the gallium atoms are not equally bonded to the atoms in the C2B3 faces of the carboranes but are slipped toward the more boron rich sides of the faces. Slippages in I and II are such that maximum differences in the Ga-C2B3 distances were 0.34 ? in I and 0.45 ? in II. The distortions were much larger in III and IV such that the carboranes are better described as being η3- and η2-bonded, respectively.
- Hosmane, Narayan S.,Lu, Kai-Juan,Zhang, Hongming,Maguire, John A.
-
-
Read Online
- Liquid gallium columns sheathed with carbon: Bulk synthesis and manipulation
-
It is impossible to fabricate isolated gallium nanomaterials due to the low melting point of Ga (29.8?°C) and its high reactivity. We report the bulk synthesis of uniform liquid Ga columns encapsulated into carbon nanotubes through high-temperature chemical reaction between Ga and CH4. The diameter of filled Ga liquid columns is a??25 nm, and their length is up to several micrometers. The thickness of the carbon sheaths is a??6 nm. Simultaneous condensation of a Ga vapor and carbon clusters results in the generation of Ga-filled carbon nanotubes. A convergent 300 kV electron beam generated in a field emission high-resolution electron microscope is demonstrated to be a powerful tool for delicate manipulation of the liquid Ga nanocolumns: they can be gently joined, cut, and sealed within carbon nanotubes. The self-organization of a carbon sheath during the electron-beam irradiation is discussed. The electron-beam irradiation may also become a decent tool for Ga-filled carbon nanotube thermometer calibration. ? 2005 American Chemical Society.
- Zhan, Jinhua,Bando, Yoshio,Hu, Junqing,Golberg, Dmitri,Nakanishi, Haruyuki
-
-
Read Online
- Collisional quenching of Ga(5p) atoms by H2, D2 and CH4
-
Collisional quenching of Ga(5p) atoms by H2, D2 and CH4 has been studied. The gallium atoms were generated by photolysis of trimethyl gallium using a KrF laser. The Ga(5p) state was populated by two-photon excitation from the ground state and cascade fluorescence from Ga(5s) atoms was analyzed to extract quenching rate constants for Ga(5p) atoms. The apparent quenching rate constants for Ga(5p) atoms are (4.6±0.3)×10-10, (3.4±0.3)×10-10 and (7.8±0.2)×10-11 cm3 molecule-1 s-1 by H2, D2 and CH4, respectively. It is found that the predominant process for the large quenching rate constants for Ga(5p) atoms by H2 and D2 is the energy transfer for Ga(5s) formation.
- Lee,Son,Bae,Ku
-
-
Read Online
- Enhanced GaN decomposition in H2 near atmospheric pressures
-
GaN decomposition is studied at metallorganic vapor phase epitaxy pressures (i.e., 10-700 Torr) in flowing H2. For temperatures ranging from 850 to 1050°C, the GaN decomposition rate is accelerated when the H2 pressure is increased a
- Koleske,Wickenden,Henry,Twigg,Culbertson,Gorman
-
-
Read Online
- Electrodeposition of GaAs from aqueous electrolytes
-
Gallium arsenide films were electrodeposited from both alkaline and acid aqueous electrolytes. Compared to other conventional methods of preparing gallium arsenide films, electrodeposition from aqueous solution has the advantages of low operating and equipment costs, relatively easy control of film properties, and no toxic volatile raw material. The cathodic deposits from an alkaline electrolyte generally were thick, porous, and powdery. With an acid electrolyte, the deposits were thinner and more compact and adherent. The effects of the following operating parameters have been characterized: applied potential, current density, electrolyte composition, cathode material, deposition temperature, pH, additives, and agitation. Secondary ion mass spectroscopy confirmed oxidation states and x-ray diffraction patterns indicated that the as-deposited films were microcrystalline GaAs which became more crystalline on annealing. Mixtures of the deposited elements of gallium and arsenic yielded crystalline gallium arsenide after annealing. Energy dispersive spectroscopy and Auger electron spectroscopy showed that the deposited films contained some oxygen. The source of the oxygen, particularly in the acid electrolytes, is discussed. A mechanistic study confirmed conditions under which arsine is formed and reacts with gallate in the alkaline solution.
- Yang,Landau,Angus
-
-
Read Online
- Shape cycle of Ga clusters on GaAs during coalescence growth
-
GaAs(1 0 0) was heated above its decomposition temperature of 585 °C bringing it into a phase separation regime where the thermodynamic favoured state is liquid Ga clusters on the surface. Varying the annealing times and temperatures provided an overview of the clustering at all stages from transitioning ripening at lower temperatures to coalescence at higher temperatures. We observed a shape cycle between round and rectangular shaped clusters during the growth. This cycle is driven by subcluster etching where pits are formed under clusters during the growth due to preferential loss of As through the liquid Ga cluster. The newly observed shape cycle is compared to a shape cycle observed previously in In on InP illustrating that shape cycles are a common feature of the decomposition of Group III-V semiconductors.
- Shorlin,Zinke-Allmang
-
-
Read Online
- Metal-Drug Interactions: Synthesis and Spectroscopic Characteristics, Surface Morphology, and Pharmacological Activity of Ephedrine–HCl Complexes with Mo(V), Nb(V), Ga(III), and Ge(IV)
-
Four new Mo(V), Nb(V), Ga(III), and Ge(IV) ephedrine complexes, [Mo(Eph)2(Cl)4].Cl, [Nb(Eph)2(Cl)3], [Ga(Eph)2(Cl)3], and [Ge(Eph)2(Cl)2] are synthesized and characterized. Composition and coordination behavior of ephedrine drug towards Mo(V), Nb(V), Ga(III), and Ge(IV) ions are deduced from microanalysis, IR spectra, molar conductance, magnetic and thermal analysis data. These support coordination of the eph ligand in its neutral state. Ephedrine has two powerful chelating sites, OH and NH, that determine its uni- or bidentate mode of action. IR spectra indicate that Mo(V) and Ga(III) coordinate to ephedrine via nitrogen atom of the NH group as a unidentate chelator with six and five coordination geometry, respectively. On the other hand, Eph ligand behaves as a monoanionic bidentate no chelating agent via the NH and deprotonated OH groups in Nb(V) and Ge(IV) complexes. Mo(V) complex demonstrates electrolytic properties, the other complexes are non-electrolytes in DMSO solutions. TG/DTG analysis makes it possible to calculate the number of solvent molecules in and outside the coordination sphere, and estimate stability of the synthesized complexes. The Eph complexes are screened in vitro for antibacterial (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus) and antifungal (Aspergillus flavus and Candida albicans) activities. Anti-cancer action of the Mo(V) and Ga(III) complexes is assessed against the human hepato cellular carcinoma (HepG-2) tumor cell line (IC50 >1000 μg/mL).
- El-Habeeb,Refat
-
p. 2163 - 2169
(2018/12/11)
-
- REDUCTANT AND METHOD FOR PRODUCING METAL USING THE SAME
-
PROBLEM TO BE SOLVED: To provide a novel reductant that can reduce metal ions by a reduction reaction in solvent, and a method for producing metal using the reductant. SOLUTION: A reductant comprises a compound represented by the general formula (where X1 and X2 are the same or different to represent a nitrogen atom or a methine group, R1, R2, R3, R4, R5 and R6 are the same or different to represent a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group or a tert-butyl group). There is also provided a method for producing metal by bringing the reductant into contact with a metal ion source in solvent. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
- -
-
Paragraph 0037
(2017/03/25)
-
- Salt-Free Reduction of Nonprecious Transition-Metal Compounds: Generation of Amorphous Ni Nanoparticles for Catalytic C-C Bond Formation
-
A salt-free procedure for the generation of a wide variety of metal(0) particles, including Fe, Co, Ni, and Cu, was achieved using 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (1), which reduced the corresponding metal precursors under mild conditions. Notably, Ni particles formed in situ from the treatment of Ni(acac)2 (acac=acetylacetonate) with 1 in toluene exhibited significant catalytic activity for reductive C-C bond-forming reactions of aryl halides in the presence of excess amounts of 1. By examination of high-magnification transmission electron microscopy images and electron diffraction patterns, we concluded that amorphous Ni nanoparticles (Ni aNPs) were essential for the high catalytic activity.
- Yurino, Taiga,Ueda, Yohei,Shimizu, Yoshiki,Tanaka, Shinji,Nishiyama, Haruka,Tsurugi, Hayato,Sato, Kazuhiko,Mashima, Kazushi
-
supporting information
p. 14437 - 14441
(2016/01/25)
-
- Low valent and hydride complexes of NHC coordinated gallium and indium
-
The reactions of the N-heterocyclic carbene 1,3-dimesitylimidazol-2-ylidene (IMes) with Ga[GaCl4], "GaI", InCl2 and GaBr3 have been examined. All reactions using a low valent gallium or indium starting material led to species of the form [{MX2(IMes)} 2], where M = Ga, X = Cl (1), I (2); M = In, X = Cl (3), with disproportionation and loss of gallium metal in the case of 2. Reaction of IMes with gallium tribromide yields the air and moisture stable complex [GaBr 3(IMes)] (4), which has been used as a precursor to the mixed bromohydrides [GaBrH2(IMes)] (5) and [GaBr2H(IMes)] (6) by (i) ligand redistribution with [GaH3(IMes)], (ii) hydride-bromide exchange with triethylsilane, and (iii) alkylation with nbutyllithium followed by β-hydride elimination (6 only). Attempts to prepare 1, or monovalent analogues such as [{GaCl(IMes)}n], by thermally induced reductive elimination of dihydrogen from the chlorohydride congeners of 5 and 6 resulted in isolation of the known compounds [IMesCl][Cl] (IMesCl = 1,3-dimesityl-2-chloroimidazolium), and/or 1,3-dimesityl-2-dihydroimidazole, and gallium metal. Preliminary photochemical NMR spectroscopy and catalytic studies of 5 and 6 aimed at reductive dehydrogenation under milder conditions are reported. Compounds 1 and 4 have been characterised by single crystal X-ray structure determination.
- Ball, Graham E.,Cole, Marcus L.,McKay, Alasdair I.
-
p. 946 - 952
(2012/03/22)
-
- Electrodeposition and characterization of Fe80Ga20 alloy films
-
Due to its high magnetostriction and good mechanical properties Fe 80Ga20 is interesting for magnetostrictive microactuators and sensors. Here we use electrodeposition to grow Fe-Ga films onto Au and Pt coated Si substrates by potentiostatic and pulse potential deposition. Composition, microstructure and structure are analysed. The desired composition of Fe80Ga20 was obtained at -1.4 VSCE and -1.5 VSCE, respectively. The origin of low reproducibility and high oxygen content up to 50 at.% is investigated. Optimum deposition conditions to achieve dense, homogeneous films with low oxygen content are identified. In these films the saturation magnetization reaches a maximum value of 1.7 T confirming the high quality of electrodeposited films.
- Iselt,Gaitzsch,Oswald,F?hler,Schultz,Schl?rb
-
p. 5178 - 5183
(2011/09/13)
-
- Tandem OLED having an organic intermediate connector
-
A tandem OLED includes an anode and a cathode. The OLED also includes at least two electroluminescent units disposed between the anode and the cathode, wherein each of the electroluminescent units includes at least one hole-transporting layer and one organic light-emitting layer. An intermediate connector is disposed between adjacent electroluminescent units, wherein the intermediate connector includes an n-doped organic layer and an electron-accepting layer, the electron-accepting layer being disposed closer to the cathode than the n-doped organic layer, and wherein the electron-accepting layer includes one or more organic materials, each having a reduction potential greater than ?0.5 V vs. a Saturated Calomel Electrode, and wherein the one or more organic materials constitute more than 50% by volume of the electron-accepting layer.
- -
-
-
- ORGANIC ELECTROLUMINESCENT DEVICE HAVING AN AZATRIPHENYLENE DERIVATIVE
-
Azatriphenylene derivatives and their use in the electron-transporting layer of an electroluminescent device that comprises an anode, a spaced-apart cathode, and at least one electron-transporting layer disposed between the spaced-apart anode and cathode. Such EL devices provide lower drive voltage, improved power efficiency, and longer operational lifetime.
- -
-
-
- A decagallane(6) cluster Ga10[Si(CMe3) 3]6 with an unprecedented structure
-
The decagallane(6) Ga10R′6 [R′ = Si(CMe3)3] adopts a quite unusual structure, which might be described as being derived from a pentagonal bipyramidal core, which is threefold capped. An alternative description is that of a conjuncto-cluster. The structure of the anionic cluster [Ga10R′6] - as well as that of Ga10R″6 [R″ = Si(SiMe3)3] are described as being built of fused octahedra. Thus, this family of decagallanes is unique in showing structural isomers in the cluster core, giving hints to the pathways of formation of these clusters, too. The novel cluster compound is characterized by X-ray crystallography. Isomeric decagallanes(6) and structural changes on reduction are studied by DFT methods.
- Linti, Gerald,Seifert, Annekathrin
-
p. 3688 - 3693
(2009/02/01)
-
- Transition metal-catalyzed dissociation of phosphine-gallane adducts: Isolation of mechanistic model complexes and heterogeneous catalyst poisoning studies
-
Attempts to induce the catalytic dehydrocoupling of the phosphine-gallane adduct Cy2PH·GaH3 (Cy = cyclohexyl) (1) by treatment with ca. 5 mol % of either the Rh(I) complex [{Rh(μ-Cl)(1,5-cod)} 2] (cod = cyclooctadiene) or the Rh(0) species Rh/Al 2O3 and [Oct4N]Cl-stabilized colloidal Rh led to catalytic P-Ga bond cleavage to generate the phosphine, H2, and Ga metal. Interestingly, subsequent treatment of the reaction mixtures with Me2NH·BH3 failed to lead to the formation of [Me2N-BH2]2 via Rh-catalyzed dehydrocoupling, which suggested that catalyst deactivation was taking place. Poisoning studies involving the treatment of the active Rh(0) catalyst with Cy2PH, PMe3, or GaH3·OEt2 showed that deactivation indeed occurred as the dehydrocoupling of Me2NH· BH3 either dramatically decreased in rate or did not take place at all. The X-ray photoelectron spectroscopy analysis of colloidal Rh(0) that had been treated with Cy2PH and PMe3 confirmed the presence of phosphorus on the catalyst surface in each case, consistent with catalyst poisoning via phosphine ligation. A mechanism for the Rh-catalyzed P-Ga bond cleavage reaction of 1 and Me3P·GaH3 (2) is proposed and involves the initial reaction of Ga-H bonds with the Rh colloid surface, which weakens and ultimately breaks the P-Ga bond. The reasonable nature of this mechanism is supported by a model reaction between the zerovalent group 9 complex Co2(CO)8 and 2 which afforded Me 3P·Ga[Co(CO)4]3 (3). Consistent with the elongated and thus weakened P-Ga bond in 3, solutions of this species in Et2O subsequently form the known complex [(Me3P)Co(CO) 3]2 (4) and Ga metal after 4 h at 25°C.
- Clark, Timothy J.,Jaska, Cory A.,Turak, Ayse,Lough, Alan J.,Lu, Zheng-Hong,Manners, Ian
-
p. 7394 - 7402
(2008/10/09)
-
- The reactions of dialkylgallium hydrides with tert-butylethynylbenzenes - A systematic investigation into the course of hydrogallation reactions
-
The reactions of bis- and tris(tert-butylethynyl)benzenes with dialkylgallium hydrides afforded two different types of products. 1,4-Di(tert-butylethynyl)benzene and dialkylgallium hydrides R2GaH bearing relatively small substituents (R = Et, nPr) gave the expected addition products with each CC triple bond inserted into a Ga-H bond. The intact GaR 2 groups are attached to those carbon atoms which are in α-position to the benzene rings, and intermolecular Ga-C interactions led to the formation of one-dimensional coordination polymers. In contrast secondary reactions with the release of the corresponding trialkylgallium derivatives GaR3 (R = Et, nPr, iPr, CH2tBu, tBu) were observed for all hydrogallation reactions involving the trisalkyne 1,3,5-tris(tert-butylethynyl) benzene. A similar reaction was observed upon treatment of the 1,4-bisalkyne with a dialkylgallium hydride bearing a relatively bulky substituent (R = neopentyl). Cyclophane type molecules are formed in all these cases with two or three gallium atoms in the bridging positions between both benzene rings. The Royal Society of Chemistry.
- Uhl, Werner,Claesener, Michael,Haddadpour, Sima,Jasper, Beate,Hepp, Alexander
-
p. 417 - 423
(2008/01/27)
-
- In situ TEM observation of synergistic electronic-excitation-effects of phase stability in III-V binary compound nanoparticles
-
Electronic-excitation-effects of phase stability in III-V binary compound nanoparticles have been studied by TEM. When GaSb particles were excited by 75 keV electrons, the compound transforms to a two-phase consisting of an antimony core and a gallium shell or an amorphous phase, or remains the original crystalline phase, depending on particle size and/or temperature. It is suggested that such nonlinear responses of the phase stability may arise from synergistic effects of bond instability under excited states, formation of high density of excited states, chemical equilibrium under excited states and temperature dependence of defects mobility. EDP Sciences/Societa? Italiana di Fisica/Springer-Verlag 2007.
- Yasuda,Tanaka,Usui,Mori,Lee
-
p. 177 - 180
(2008/10/09)
-
- The [Ga2(C5Me5)]+ ion: Bipyramidal double-cone structure and weakly coordinated, monovalent Ga +
-
(Figure Presented) Partial protolysis of GaCp* with [H-(OEt 2)2]+[BArF]- afforded the GaI compound [Ga2Cp*]+[BAr F]- (see structure). Experimental and computational studies confirm the mainly ionic structure of the cation, in which the Ga + ions are only weakly covalently stabilized by a bridging Cp* ligand. Initial experiments point to the interesting synthetic potential of this compound as a source for Ga+ in solution.
- Buchin, Beatrice,Gemel, Christian,Cadenbach, Thomas,Schmid, Rochus,Fischer, Roland A.
-
p. 1074 - 1076
(2007/10/03)
-
- Hydrodesulfurization of dibenzothiophene and 4,6-dimethyl-dibenzothiophene: Gallium effect over NiMo/Al2O3 sulfided catalysts
-
The influence of gallium on alumina-supported NiMo catalysts was investigated by correlating their physicochemical properties with the hydrodesulfurization (HDS) activity of model molecules. The Ga-γ-Al 2O3 supports were prepared by
- Altamirano, Efrain,De Los Reyes, Jose Antonio,Murrieta, Florentino,Vrinat, Michel
-
p. 403 - 412
(2008/10/09)
-
- Decomposition of monochlorogallane, [H2GaCl]n, and adducts with amine and phosphine bases: Formation of cationic gallane derivatives
-
Thermal decomposition of monochlorogallane, [H2GaCl] n, at ambient temperatures results in the formation of subvalent gallium species. To Ga[HGaCl3], previously reported, has now been added a second mixed-valence solid, Ga4-[HGaCl3] 2[Ga2Cl6] (1), the crystal structure of which at 150 K shows a number of unusual features. Adducts of monochlorogallane, most readily prepared from the hydrochloride of the base and LiGaH4 in appropriate proportions, include not only the 1:1 molecular complex Me 3P·GaH2Cl (2), but also 2:1 amine complexes which prove to be cationic gallane derivatives, [H2Ga(NH2R) 2]+Cl-, where R = tBu (3a) or sBu (3b). All three of these complexes have been characterized crystallographically at 150 K.
- Tang, Christina Y.,Downs, Anthony J.,Greene, Tim M.,Marchant, Sarah,Parsons, Simon
-
p. 7143 - 7150
(2008/10/09)
-
- Kinetics and mechanism of free-surface vaporization of groups IIA, IIIA and IVA nitrides analyzed thermogravimetrically by the third-law method
-
The purpose of this work was to re-measure the enthalpy ΔrHT° of free-surface vaporization of hexagonal (h) Mg3N2, AlN, GaN, InN and Si3N4 and cubic (c) BN by the third-law method and by comparing them with the enthalpies calculated from thermodynamics to deduce the composition of primary products (bN and cN2) for the generalized decomposition reaction: MaNb+2c ? aM + bN + cN2. In addition to these nitrides, the literature data were used for the investigation of vaporization of h-Be3N2 and c-AlN and c-GaN. The relative standard deviation in determination of ΔrHT° values is ≤1% and in determination of b/(b + 2c) ratio is better than 2-4%. As a result of this study, some important features in the decomposition mechanism of different nitrides were revealed: the identity in composition of primary products for h-Be3N2 and h-Mg 3N2 (b/(b + 2c) = 0.75) and h-AlN and h-GaN (b/(b + 2c) = 0.42) and the release of only molecular nitrogen in cases of c-BN, c-AlN and c-GaN (b/(b + 2c) = 0). The last feature that was observed earlier for cubic metal oxides [B.V. L'vov, V.L. Ugolkov, F.F. Grekov, Kinetics and mechanism of free-surface vaporization of zinc, cadmium and mercury oxides analyzed thermogravimetrically by the third-law method, Thermochim. Acta 411 (2004) 187-193.] supports the effect of crystal symmetry on the decomposition mechanism. The distance between the closest atoms (NN) in a crystalline lattice has a secondary or no effect on the composition of primary products. These features might be useful for the development/improving of appropriate technologies (including nano-technologies) for production of solid materials by the chemical vapour deposition.
- L'vov, Boris V.,Ugolkov, Valery L.
-
-
- Group(III)-metal-hydrides with a guanidino-type ligand
-
A compound of formula (I) wherein X is aluminium, gallium or indium; each Y, which may be the same or different, is nitrogen or phosphorus; R1and R2, which may be the same or different, are hydrogen, halogen or alkyl; and R3to R7, which may be the same or different, are hydrogen or a saturated group, or R3and R4, or R5and R6together represent a saturated divalent link thus completing a ring.
- -
-
Page column 3-4
(2008/06/13)
-
- Dehydrogenative Ga-Ga coupling and hydrogallation in gallium hydride complexes of 3,5-dimethylpyridine
-
The 2:1 complex of 3,5-dimethylpyridine (L′) and dichlorogallane, (L′)2GaHCl2, undergoes dehydrogenative Ga-Ga coupling in boiling toluene to give high yields of (L′)Cl 2Ga-GaCl2(L′). The structure of the dinuclear product (which has C2h symmetry) has been determined [Ga-Ga′ 2.4000(8) A]. By contrast, the 1:1 complex of L′ and gallium trihydride, (L′)GaH3, on prolonged standing at 20°C or when treated with excess ligand L′, is converted into the hydrogallation product, (L′)(L′H)GaH2. In this product, the gallium atom is attached to a pyridine donor ligand L′ and a 4-hydropyridyl substituent, as proven by a crystal structure determination and by NMR and IR spectral studies. The Ga-N bond length is very significantly shorter for the hydropyridyl as compared to the pryridine group, and the carbon atom C 4 of the former has become the center of an aliphatic CH2 group with its 1H and 13C resonances shifted into the corresponding upfield regions. The C3-C4 and C 4-C5 linkages have been converted into single bonds, with double bonds localized at C2-C3 and C5-C 6 of the (L′H) heterocycle. While the N-Ga-N angle is very small at only 103(1)°, the H-Ga-H angle is exceedingly large at 127(2)°, indicating a strong steric pressure of the seemingly small hydride ligands and that hydride functions thus are to be considered as bulky substituents.
- Nogai, Stefan D.,Schmidbaur, Hubert
-
p. 5877 - 5880
(2008/10/09)
-
- Molten gallium as a catalyst for the large-scale growth of highly aligned silica nanowires
-
The vapor-liquid-solid (VLS) process is a fundamental mechanism for the growth of nanowires, in which a small size (5-100 nm in diameter), high melting point metal (such as gold and iron) catalyst particle directs the nanowire's growth direction and defines the diameter of the crystalline nanowire. In this article, we show that the large size (5-50 μm in diameter), low melting point gallium droplets can be used as an effective catalyst for the large-scale growth of highly aligned, closely packed silica nanowire bunches. Unlike any previously observed results using gold or iron as catalyst, the gallium-catalyzed VLS growth exhibits many amazing growth phenomena. The silica nanowires tend to grow batch by batch. For each batch, numerous nanowires simultaneously nucleate, grow at nearly the same rate and direction, and simultaneously stop growing. The force between the batches periodically lifts the gallium catalyst upward, forming two different kinds of products on a silicon wafer and alumina substrate. On the silicon wafer, carrot-shaped tubes whose walls are composed of highly aligned silica nanowires with diameters of 15-30 nm and length of 10-40 μm were obtained. On the alumina substrate, cometlike structures composed of highly oriented silica nanowires with diameters of 50-100 nm and length of 10-50 μm were formed. A growth model was proposed. The experimental results expand the VLS mechanism to a broader range.
- Pan, Zheng Wei,Dai, Zu Rong,Ma, Chris,Wang, Zhong L.
-
p. 1817 - 1822
(2007/10/03)
-
- Chemical transport in control over the composition of nonstoichiometric crystals
-
We show that the composition of low-volatility two-component compounds (gallium selenides) can be governed by chemical transport (CT) without the crystals being destroyed. Given a sufficiently prolonged annealing, the set composition of phases is controlled by the temperatures of hot and cold zones and the nature of the precursors. The composition is presented as a function of hot-zone and cold-zone temperatures. The role of transport agents (here, gallium iodides) in chemical transport is discussed. The possibility of expanding the method to other binary systems with low-volatility intermediate phases is considered.
- Zavrazhnov,Turchen,Goncharov,Zlomanov
-
p. 497 - 506
(2008/10/08)
-
- Synthesis and X-ray crystal structure of [Me2GaBi(SiMe3)2]3
-
[Me2GaBi(SiMe3)2]3 (1) was synthesized in high yield by the equimolar reaction of Me2GaH and Bi(SiMe3)3 and characterized by mass and multinuclear NMR spectroscopy and by single-
- Thomas, Florian,Schulz, Stephan,Nieger, Martin
-
p. 2793 - 2795
(2008/10/08)
-
- Physiologically acceptable foamable formulation and foam
-
There is described a foamable formulation comprising a foamable carrier and an active ingredient which may be admixed with the carrier or packaged separately and dispersed into the carrier during the foaming process. Alginate gel is a preferred foamable carrier. The foam produced from such a formulation, and a foam sheet produced by drying the foam, also form part of the invention. The formulation, foam and foam sheet are especially useful for medical applications, for example in treating burns. As apparatus to store the components of the formulation and to generate the foam is also described.
- -
-
-
- Synthesis and structure of a Ga84R204- cluster - A link between metalloid clusters and fullerenes?
-
New record size! The reaction of Li[N(SiMe3)2] with a metastable solution of GaBr leads to good yields of [Ga84{N(SiMe3)2}20]4- (see picture), the largest Group 13 metalloid cluster that has been structurally characterized to date. On the basis of its highly symmetrical structure elements with predominantly covalent bonds, it is classified between the metalloid Al77 cluster and the fullerenes with respect to its bonding character.
- Schnepf, Andreas,Schnoeckel, Hansgeorg
-
p. 712 - 715
(2007/10/03)
-
- Some chemical properties of monochlorogallane: Decomposition to gallium(I) trichlorogallate(III), Ga+[GaCl3H]-, and other reactions
-
Thermal decomposition of monochlorogallane, [H2GaCl]n, at ambient temperatures releases H2 and results in the formation of gallium(I) species, including the new compound Ga[GaHCl3], which has been characterized crystallographically at 100 K (monoclinic P21/n, a = 5.730(1), b = 6.787(1), c = 14.508(1) A, β = 97.902(5)°) and by its Raman spectrum. The gallane suffers symmetrical cleavage of the Ga(μ-Cl)2Ga bridge in its reaction with NMe3 but unsymmetrical cleavage, giving [H2Ga(NH3)2]+Cl-, in its reaction with NH3. Ethene inserts into the Ga-H bonds to form first [Et(H)GaCl]2 and then [Et2GaCl]2.
- Johnsen,Downs,Goode,Greene,Himmel,Mueller,Parsons,Pulham
-
p. 4755 - 4761
(2008/10/08)
-
- Preparation and properties of gallaborane, GaBH6: Structure of the gaseous molecule H2Ga(μ-H)2BH2 as determined by vibrational, electron diffraction, and ab initio studies, and structure of the crystalline solid at 110 K as determined by X-ray diffraction
-
Gallaborane (GaBH6, 1), synthesized by the metathesis of LiBH4 with [H2GaCl]n at ca. 250 K, has been characterized by chemical analysis and by its IR and 1H and 11B NMR spectra. The IR spectrum of the vapor at low pressure implies the presence of only one species, viz. H2Ga(μ-H)2BH2, with a diborane-like structure conforming to C2ν symmetry. The structure of this molecule has been determined by gas-phase electron diffraction (GED) measurements afforced by the results of ab initio molecular orbital calculations. Hence the principal distances (rα in A) and angles (∠α in deg) are as follows: r(Ga···B), 2.197(3); r(Ga-Ht), 1.555(6); r(Ga-Hb), 1.800(6); r(B-Ht), 1.189(7); r(B-Hb), 1.286(7); ∠Hb-Ga-Hb, 71.6(4); and ∠Hb-B-Hb, 110.0(5) (t = terminal, b = bridging). Aggregation of the molecules occurs in the condensed phases. X-ray crystallographic studies of a single crystal at 110 K reveal a polymeric network with helical chains made up of alternating pseudotetrahedral GaH4 and BH4 units linked through single hydrogen bridges; the average Ga···B distance is now 2.473(7) A. The compound decomposes in the condensed phases at temperatures exceeding ca. 240 K with the formation of elemental Ga and H2 and B2H6. The reactions with NH3, Me3N, and Me3P are also described.
- Downs,Greene,Johnsen,Brain,Morrison,Parsons,Pulham,Rankin,Aarset,Mills,Page,Rice
-
p. 3484 - 3497
(2008/10/08)
-
- Vaporization of Sr- and Mg-Doped Lanthanum Gallate and Implications for Solid Oxide Fuel Cells
-
Vaporization of the La0.85Sr0.15Ga0.85Mg0.15O 2.85, and La0.90Sr0.10Ga0.80Mg0.20O 2.85 perovskite phases was investigated by the use of Knudsen e
- Kuncewicz-Kupczyk, Wioletta,Kobertz, Dietmar,Miller, Miroslaw,Singheiser, Lorenz,Hilpert, Klaus
-
p. E276-E281
(2008/10/08)
-
- Influence of temperature and of structure of antimony substrate on gallium diffusion into the GaSb semiconductor compound
-
The diffusion coefficient of Ga electrodeposits on Sb electrodeposited thin films, either amorphous or crystalline, was investigated to determine the influence of the morphology and structure of the antimony substrates on the diffusion and reaction process. The Ga/Sb bilayer was studied by SEM-EDS and X-ray diffraction before and after heating at temperatures of 50, 75 and 100 °C. The formation of the GaSb semiconductor compound was particularly considered and the activation energy and frequency factor of the process was determined. At these temperatures, Ga was at least partially molten and the diffusion coefficient showed that the geometrical factor was prevailing over the structural one. For example, at 75 °C, the values of the diffusion coefficient were 1.5×10-17 and 6.3×10-17 m2 s-1 for the amorphous and crystalline antimony, respectively. On the contrary, at 20 °C, a temperature at which Ga is in the solid state, the structural factor prevailed over the geometrical one and values were obtained lower by around three orders of magnitude. The prevailing influence at 20 °C was identical to that previously observed for In diffusion into amorphous and crystalline Sb with InSb formation. The experimental results, both at low and high temperatures, are discussed also taking the behaviour of the In-Sb system into account.
- Kozlov, Valentin M.,Peraldo Bicelli, Luisa
-
p. 161 - 167
(2008/10/08)
-
- Gas Transport in the Ga-Se-I System and the Possibility of Controlled Synthesis of Gallium Selenides
-
The processes of chemical transport in the Ga-Se-I system are investigated. It is found that the starting GaSe disproportionates when the temperature difference has a critical value of ΔT. The possibility of controlling the composition of gallium selenide samples in the GanSem(S)-Ga(1)-V(Gal+GaI3) system is demonstrated. The processes investigated, which permit one to control the composition of low-volatility compounds, can be expanded to other systems.
- Zavrazhnov,Turchen,Goncharov,Prigorodova
-
-
- Reaction of decamethylsilicocene with group 13 element halides: Insertions, rearrangements, and eliminations
-
In the reaction of decamethylsilicocene (1; (Me5C5)2Si) with halides or organohalides of trivalent boron, aluminum, gallium, and indium, quite different and sometimes very complex pathways are observed which include adduct formation, 1,2-halide or -alkyl shifts, 1,2-dyotropic rearrangements, and reductive elimination and oxidative addition reactions. Cp*BCl2 (Cp* = pentamethylcyclopentadienyl), BCl3, and BBr3 reacted with 1 to form the pentacarba-nido-hexaboronium salts [Cp*SiCl2BCp*]+[Cp*BCl3]- (3a) and [Cp*SiX2BCp*]+-[BX4]- (3b, X = Cl; 4, X = Br). A second product (5b) of composition Cp*3Si2Br4B with an arachno-cluster framework was isolated from the reaction with BBr3. With AlCl3 and AlBr3 metathesis reactions gave the ionic compounds [Cp*2Al]-[AlX4]- (6a,b, X = Cl, Br), respectively. The formation of 6a,b is the result of a Lewis-base-catalyzed dismutation of Cp*AlX2 in which 1 is the base, as proved by separate experiments. The compound Cp*Al-(Me)Cl (7) was formed in the reaction of 1 with Me2AlCl. Silicocene 1 functioned as a dehalogenating agent in its reactions with GaCl3, GaBr3, Cp*GaBr2, InCl3, and InBr3, giving the corresponding monovalent, metastable ( GaCl , GaBr ) or stable (Cp*Ga, InCl, InBr) species. All new compounds were characterized by NMR (1H, 13C, 11B, 29Si) and mass spectrometry. The solid-state structures of 3a and 5b were determined by X-ray diffraction analysis.
- Holtmann, Udo,Jutzi, Peter,Kühler, Thorsten,Neumann, Beate,Stammler, Hans-Georg
-
p. 5531 - 5538
(2008/10/08)
-