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Hf27Si6P10, a novel metal-rich compound with P2 groups
2000
The new ternary metal rich compound Hf27Si6P10 has been synthesized by reduction of HfP with Hf and Si; Hf27Si6P10 crystallizes in a new structure type, a characteristic and unexpected feature of which is the presence of P2 groups; the structural results are interpreted with the aid of high-level band structure calculations.
A Cation-Captured Palladium(0) Anion: Synthesis, Structure, and Bonding of [PdBr(PPh3)2]− Ligated by an N-Heterocyclic Phosphenium Cation
2009
Unsaturated N-heterocyclic phosphenium cations (uNHP) stabilize the [Pd0(PR3)2X]− anion proposed over the past decade to be the crucial but elusive intermediate in palladium-catalyzed cross-coupling reactions (X = halide). Insertion of metal into the P−Br bond of the precursor mesityl-substituted bromophosphine gives the structurally characterized Pd(0)-phosphenium complex (uNHPMes)Pd(PPh3)2Br, which features a long Pd−Br bond (2.7240(9) A) and the shortest known Pd−P bond (2.1166(17) A). The reaction is proposed to proceed by an associative pathway involving a Pd-bromophosphine complex that undergoes P-to-Pd bromide transfer.
Synthesis, Structure, and Electrical Properties of Ta 4 FeTe 4
1995
Ta4FeTe4 has been synthesized and its structure determined by single-crystal X-ray methods. It crystallizes in the ortho-rhombic space group Pbam with Z = 4 and a = 10.514(5), b = 18.275(7), and c = 4.815(1) A. Ta4FeTe4 has a chain structure built up by Fe-centered Ta8-square antiprisms sharing common square faces. The resistivity of Ta4FeTe4 has been measured by a two-point method. Ta4FeTe4 shows metallic behavior. The structure of Ta4FeTe4 is discussed in relation to other early transition metal cluster compounds. A rational approach to the synthesis of related compounds is proposed.
Synthesis of μ-C2S44− Cobalt Complexes by Activation of the 1,3,4,6-tetrathiapentalene-2,5-dione, and Electrochemical Study of [(Cp*Co)2(μ-C2S4)]
2002
The bimetallic complex [Cp(*)Co)2(μ-C2S4)] in which the two metal centres are linked by an ethylenetetrathiolate C2S44− unit, was synthesized in high yield by oxidative addition of 1,3,4,6 tetrathiapentalene-2,5-dione to [Cp(*)Co(CO)2]. The X-ray crystal structure of the intermediate product Cp*Co(dmid) (dmid2− = 4,5-disulfanyl-1,3-dithiol-2-onate) is presented. The electrochemical behaviour of the [(Cp*Co)2(μ-C2S4)] complex was studied in detail in the oxidative range. This study has shown that the nature of the product obtained after oxidation depends on the presence of complexing agent in the solution. The mechanism has been elucidated in a CH2Cl2 solution in the presence of P(OMe)3. In …
Ferrocenyl-functionalized tetranuclear gold(I) and gold(I)-copper(I) complexes based on tridentate phosphanes
2013
Tetranuclear AuI–FeII dimetallic and AuI–CuI–FeII trimetallic complexes bearing ferrocenyl (Fc) groups have been assembled by using two triphosphane ligands, namely, (PPh2CH2)2PPh (dpmp) and (PPh2)3CH (tppm). The compositions and structural type of the clusters are dependent on the stereochemistry of the P donor ligands. The complexes [tppmAu3Cu(C2R)3]PF6 [R = Fc (1) and 4-C6H4-Fc (2)] adopt a trigonal pyramidal {Au3Cu} arrangement of the coordinating metal core, whereas for the compounds with the linear triphosphane [Au4(dpmp)2(C2R)2](PF6)2 [R = Fc (3) and 4-C6H4-Fc (4)], a planar rhomboidal {Au4} framework was found. Clusters 1–4 were characterized by NMR spectroscopy and ESI-MS measureme…
ChemInform Abstract: Modular Metal Chalcogenide Chemistry: Secondary Building Blocks as a Basis of the Silicate-Type Framework Structure of CsLiU(PS4…
2012
The new title compound is synthesized from a mixture of U, P2S5, Li2S, Cs2S, and S in the molar ratio 2:2:1:1:4 (sealed silica tube, 700 °C, 3 d).
Determination of metal inventory and current efficiency in commercial aluminum reduction cells
1971
A method for the determination of the metal inventory in commercial aluminum reduction cells, based on radioisotope dilution, has been developed, employing a198Au tracer. By taking a large number of samples from the cells, the current efficiency is evaluated from the slope of the cumulative metal inventory vs time data. The method allows a determination of the current efficiency over a period of 2 to 3 days with a relative precision of approximately 1 pct. The paper gives a thorough discussion of the sources of error inherent in the procedure suggested.
Catalytic conversion of glucose to 5-hydroxymethylfurfural over biomass-based activated carbon catalyst
2020
Abstract Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been widely explored research problem recently, especially from the perspective of more sustainable heterogeneous catalysts. In this study, activated carbon was first produced from a lignocellulosic waste material, birch sawdust. Novel heterogeneous catalysts were then prepared from activated carbon by adding Lewis or Bronsted acid sites on the carbon surface. Prepared catalysts were used to convert glucose to HMF in biphasic water:THF system at 160 °C. The highest HMF yield and selectivity, 51% and 78%, respectively, were obtained in 8 h with a catalytic mixture containing both Lewis and Bronsted a…
Atomistic Modeling of a New Storage
2008
It was observed that Me/Li2O and Me/LiF nanocomposites (Me is a metal that does not alloy with lithium) are able to exhibit an extra Li storage typically beyond the uptake of stoichiometric Li in the potential window 1.2 0.02 V, with pseudo-capacitive behavior and high-rate performance. Among the composites, the Ru/Li2O exhibits a high extra Li storage at this low potential. Moreover, the Li2O matrix allows one a higher storage in contact with transition metal than the LiF matrix [1,2]. To clarify the mechanism of the Li interfacial storage anomaly, we have performed comparative first principles calculations on the atomic and electronic structure of polar Ti/Li2O(111) and nonpolar Cu/LiF(00…
cis-Diazido[bis(diphenylphosphino)methane-κ2P,P′]ruthenium(II) dichloromethane 0.42-solvate
2006
Submitted by António Freitas (amsf@uma.pt) on 2019-06-13T13:44:22Z No. of bitstreams: 1 cis-Diazidobis(diphenylphosphino)methane-j2PP000ruthenium(II) dichloromethane 0.42-solvateJoãoRodrigues.pdf: 167616 bytes, checksum: 2ba0b7a76027be3eda26ce11d43fec66 (MD5) Made available in DSpace on 2019-06-13T13:44:22Z (GMT). No. of bitstreams: 1 cis-Diazidobis(diphenylphosphino)methane-j2PP000ruthenium(II) dichloromethane 0.42-solvateJoãoRodrigues.pdf: 167616 bytes, checksum: 2ba0b7a76027be3eda26ce11d43fec66 (MD5) Previous issue date: 2006 info:eu-repo/semantics/publishedVersion