Online ISSN : 2186-2451
Print ISSN : 1344-3542
ISSN-L : 1344-3542
Volume 76 , Issue 6
Showing 1-10 articles out of 10 articles from the selected issue
  • Yasushi KANZAKI, Noriko SUZUKI
    2008 Volume 76 Issue 6 Pages 402-411
    Published: June 05, 2008
    Released: March 22, 2012
    Solid NMR was used to elucidate the lithium accommodation/extraction reaction in various transition metal oxides. The first study was the lithium ion exchange reaction of titanium antimonic acid (TiSbA). The effect of hydration on the selectivity of lithium ion in the solid phase was examined using 7Li NMR. The second study was the irreversible ion exchange behavior of HNbO3. The selectivity for the lithium ion and the irreversible behavior were examined using 1H and 7Li NMR. The third study was the isotope separation between 6Li and 7Li in various inorganic ion exchangers. The high isotope separation coefficient was ascribed to the degree of dehydration during the ion exchange reaction. The degree of dehydration was examined by 1H and 7Li NMR studies. The last study was determining the mechanism of the lithium accommodation/extraction reaction of λ-MnO2 in an aqueous solution. The different paths between the accommodation and extraction and the formation of MnO4 during the accommodation were determined by chemical analysis. The Knight shift in the 7Li MAS-NMR spectra of Li0.5MnO2 suggested the localization of the electron density on the lithium nuclei. An XPS study also suggested the presence of an electron density on the lithium nuclei. A pH-independent redox couple was assumed to account for the accommodation/extraction reaction of lithium ions, such as Li(I)/Li(0).
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  • Kazuhiro YAMADA, Mitsutoshi OKANO
    2008 Volume 76 Issue 6 Pages 412-417
    Published: June 05, 2008
    Released: March 22, 2012
    Diphenylgermyl anion (Ph2GeH) was successfully generated and accumulated in the cathode compartment at −50°C by typically 1 F mol−1 electrolysis of diphenylgermane in DMF using tetrabutylammonium tetrafluoroborate as the supporting electrolyte. Similarly, diphenylgermyl dianion (Ph2Ge=) was successfully generated and accumulated at −50°C by typically 3 F mol−1 electrolysis of diphenylgermane. Accumulation of the anion species was confirmed by NMR spectroscopy of the corresponding electrolyte solutions and observation of alkylated products in reactions with various haloalkanes. The anion and the dianion gave the alkylated and dialkylated products in 20–30% yields upon reactions with various haloalkanes, respectively. Stability of the anions were also examined by NMR spectroscopy and it was found that the both anions were almost stable at −40°C, but they slowly decomposed at −20°C, and rapidly decomposed at the room temperature. A typical anion character, one electron transfer ability, was evaluated by measuring their oxidation potentials. Diphenylgermyl anion and diphenylgermyl dianion showed similar oxidation potentials. However, that of diphenylgermyl dianion needs verification by future measurements.
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