A novel metal-chain extension reaction: synthesis of (X)[Os(CO)3(CN-t-Bu)]nMn(CO)5 (X = Cl, Br, I; n = 1, 2, 3)

2002 ◽  
Vol 80 (3) ◽  
pp. 281-291 ◽  
Author(s):  
Faming Jiang ◽  
Hilary A Jenkins ◽  
David F Green ◽  
Glenn PA Yap ◽  
Roland K Pomeroy
Keyword(s):  
Room Temperature ◽  
Chain Extension ◽  
Reverse Direction ◽  
Mechanism Of Formation ◽  
Carbonyl Ligand ◽  
Major Isomer ◽  
Metal Metal ◽  
Halide Ligand ◽  
Metal Chain

Complexes of formula (X)[Os(CO)3(CN-t-Bu)]nMn(CO)5 (X = Cl, Br, I; n = 1, 2, 3) have been prepared by the reaction of Os(CO)4(CN-t-Bu) with Mn(CO)5(X) in hexane at room temperature. The characterization of the complexes included the crystal structures of compounds with X = I, n = 1, 3 and X = Cl, Br, n = 2 (2ClA and 2BrB). The trinuclear products were isolated as two isomers. The major isomer (2XA) has an isocyanide ligand attached to each osmium atom, whereas the minor isomer (2XB) has both of these ligands bound to the terminal Os atom. The structures contain OsnMn chains with unbridged Os—Mn bonds (range of lengths are 2.870(1)–2.9245(8) Å) and for compounds with n = 2 or 3 Os—Os bonds (range of lengths are 2.8812(4)–2.8928(5) Å). The mechanism of formation is believed to involve replacement of a CO ligand with the 18e- ligand Os(CO)4(CN-t-Bu) at the metal with the coordinated halide, followed by a rearrangement in which the halide ligand migrates to the donor Os atom with concomitant migration in the reverse direction of a carbonyl ligand. The preparation of (OC)4(t-BuNC)OsMn(CO)4(Cl) with an Os–Mn dative bond is also reported along with the (OC)4(t-BuNC)OsRe(CO)4(X) analogues.Key words: manganese–osmium, rhenium–osmium, dinuclear, metal chain, dative metal–metal bond.

Dicarbonylcyclopentadienyliridium, (η-C5H5)Ir(CO)2, as a ligand

1999 ◽  
Vol 77 (8) ◽  
pp. 1327-1335 ◽  
Author(s):  
Faming Jiang ◽  
Kumar Biradha ◽  
Weng Kee Leong ◽  
Roland K Pomeroy ◽  
Michael J Zaworotko
Keyword(s):  
Crystal Structures ◽  
Time Scale ◽  
Room Temperature ◽  
Donor Ligand ◽  
Carbonyl Ligands ◽  
Metal Bond ◽  
Metal Metal

The following complexes, in which CpIr(CO)2 acts as a 2e donor ligand, have been prepared: Cp(OC)2IrW(CO)5 (1), Cp(OC)2IrRu(CO)3(SiCl3)2, Cp(OC)2IrOs(CO)3(GeCl3)(Cl) (2), Cp(OC)2IrOs(CO)3(X)2 (X = Cl, Br (3), I). The characterization of the complexes included the crystal structures of 1, 2, and 3, which reveal that all contain an unbridged metal-metal bond. The carbonyl ligands of 1 in solution undergo exchange on the NMR time scale above -40°C. With the exception of 2, all the complexes dissociate in solution at room temperature, some rapidly so. Only in the case of 3 is an equilibrium with the dissociation products established. The results indicate that CpIr(CO)2 is a weak ligand.Key words: tungsten, osmium, iridium, binuclear.

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

scholarly journals Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13245-13255
Author(s):  
Mehdi Davoodi ◽  
Fatemeh Davar ◽  
Mohammad R. Rezayat ◽  
Mohammad T. Jafari ◽  
Mehdi Bazarganipour ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnesium Aluminate ◽  
Synthesis And Characterization ◽  
Magnesium Aluminate Spinel ◽  
Adsorption Behaviour ◽  
Zeolitic Imidazolate Framework ◽  
Simple Method

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios.

Processing by Pulsed Laser Deposition and Structural, Morphological and Chemical Characterization of Bi-Pb-Sr-Ca-Cu-O and Bi-Pb-Sb-Sr-Ca-Cu-O Thin Films

2010 ◽  
Vol 75 ◽  
pp. 202-207
Author(s):  
Victor Ríos ◽  
Elvia Díaz-Valdés ◽  
Jorge Ricardo Aguilar ◽  
T.G. Kryshtab ◽  
Ciro Falcony
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Chemical Characterization ◽  
Laser Deposition ◽  
Nominal Composition ◽  
Deposition Parameters ◽  
The Relationship

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) and Bi-Pb-Sb-Sr-Ca-Cu-O (BPSSCCO) thin films were grown on MgO single crystal substrates by pulsed laser deposition. The deposition was carried out at room temperature during 90 minutes. A Nd:YAG excimer laser ( = 355 nm) with a 2 J/pulse energy density operated at 30 Hz was used. The distance between the target and substrate was kept constant at 4,5 cm. Nominal composition of the targets was Bi1,6Pb0,4Sr2Ca2Cu3O and Bi1,6Pb0,4Sb0,1Sr2Ca2Cu3OSuperconducting targets were prepared following a state solid reaction. As-grown films were annealed at different conditions. As-grown and annealed films were characterized by XRD, FTIR, and SEM. The films were prepared applying an experimental design. The relationship among deposition parameters and their effect on the formation of superconducting Bi-system crystalline phases was studied.

scholarly journals Synthesis and Characterization of Lithium-Ion Conductive LATP-LaPO4 Composites Using La2O3 Nano-Powder

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3502
Author(s):  
Fangzhou Song ◽  
Masayoshi Uematsu ◽  
Takeshi Yabutsuka ◽  
Takeshi Yao ◽  
Shigeomi Takai
Keyword(s):  
Room Temperature ◽  
Conduction Mechanism ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Nano Powder ◽  
Powder Addition

LATP-based composite electrolytes were prepared by sintering the mixtures of LATP precursor and La2O3 nano-powder. Powder X-ray diffraction and scanning electron microscopy suggest that La2O3 can react with LATP during sintering to form fine LaPO4 particles that are dispersed in the LATP matrix. The room temperature conductivity initially increases with La2O3 nano-powder addition showing the maximum of 0.69 mS∙cm−1 at 6 wt.%, above which, conductivity decreases with the introduction of La2O3. The activation energy of conductivity is not largely varied with the La2O3 content, suggesting that the conduction mechanism is essentially preserved despite LaPO4 dispersion. In comparison with the previously reported LATP-LLTO system, although some unidentified impurity slightly reduces the conductivity maximum, the fine dispersion of LaPO4 particles can be achieved in the LATP–La2O3 system.

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