Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 59 , Issue 6
Showing 1-50 articles out of 68 articles from the selected issue
  • Eiji Iwamatsu, Ken-ichi Aika, Takaharu Onishi
    1986 Volume 59 Issue 6 Pages 1665-1669
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The properties and reactivities of surface oxygen species including O on V2O5/SiO2 were studied in connection with the oxidative dehydrogenation of C2H6 by N2O. O was formed through N2O on reduced V2O5 supported on SiO2 which had been prepared from tetraethyl silicate, whereas it was not formed on V2O5 supported on SiO2 obtained from other sources. One mole of O on V2O5/SiO2 was found to react with one mole of C2H6 at 298K. No oxygen species other than O reacted with C2H6 at 298K. The surface reaction mechanism was discussed, and ethoxide was considered to be one of the surface intermediates. All the other surface oxygens but O reacted with C2H6 above 573K. Since a catalytic oxidative dehydrogenation reaction of C2H6 was active above 573K, the surface oxygens other than O were considered to be responsible for this reaction. The possibility of O as the reaction intermediate was also discussed.
  • Shun-ichiro Sasaki, Shigeru Tsunashima, Shin Sato
    1986 Volume 59 Issue 6 Pages 1671-1674
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Absolute cross sections for quenching NH(c1Π) by the use of several inorganic molecules were determined at room temperature by using a phase-shift method. The NH(c1Π) radicals were produced by the photolysis of HN3 using an amplitude-modulated Xe-resonance lamp. The results obtained were as follows: 0.01(He), 12(HN3), 48(NO), 49(CO), and 30(CO2) in units of 10−16 cm2. In the case of NO, the 336 nm emission was enhanced, which suggests that NO quenches NH(c1Π) to NH(A3Π). From the phase difference between the 325 and 336 nm emissions, the quenching cross-section of NO for NH(A3Π) was estimated to be 60×10−16 cm2.
  • Shun-ichiro Sasaki, Akiko Kano, Shigeru Tsunashima, Shin Sato
    1986 Volume 59 Issue 6 Pages 1675-1681
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The cross-sections for quenching NH(c1Π) and NH(A3Π) by hydrocarbons were determined at room temperature by using a phase-shift method. The NH(c1Π) was produced by the photolysis of HN3 using an amplitude-modulated Xe-resonance lamp. The apparent decay rate of the NH(c1Π) was estimated from the difference in phase angle between the excitation light and the fluorescence of NH(c1Π) at 325 nm. In the presence of Xe, the fluorescence of NH(A3Π) at 336 nm was enhanced. The difference in the phase angle between the fluorescences at 325 and 336 nm was found to correlate with the decay rate of NH(A3Π). From the decay rates obtained in the presence of hydrocarbons, the quenching cross-sections were determined.
  • Tohru Inoue, Kiyotaka Kojima, Ryosuke Shimozawa
    1986 Volume 59 Issue 6 Pages 1683-1687
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Kinetic and equilibrium measurements were carried out for the complexation reaction of nickel(II) malate and nickel(II) tartrate in an aqueous solution at 20 °C and at pressures up to 100 MPa. From the pressure dependence of the stability constant and the rate constant, the reaction volume, ΔV0, and the activation volume, ΔVf*, for the complex formation were estimated as follows: ΔV0=17.8±0.6 cm3 mol−1 and ΔVf*=13.8±0.6 cm3 mol−1 for nickel(II) malate, and ΔV0=17.8±0.5 cm3 mol−1 and ΔVf*=13.7±1.2 cm3 mol−1 for nickel(II) tartrate. Comparing the ΔV0 values with those obtained for other carboxylate ligands, it was inferred that both malate and tartrate ions form a six-membered chelate complex coordinated by carboxyl and hydroxyl oxygens. The rate-determining step of the overall complexation reaction was assigned to the first bond formation process based on the ΔVf* value with the correction for the volume change associated with the outer-sphere complex formation.
  • Reiko Saito, Yoshinori Kidani
    1986 Volume 59 Issue 6 Pages 1689-1694
    Published: 1986
    Released: June 27, 2006
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    Four 1,2-diamine ligands, (1RS,2SR)-1-methyl-1,2-cyclohexanediamine(1m-chxn), (1R,2S,3R)-3-methyl-1,2-cyclohexanediamine(R,S,R-3m-chxn), (1S,2R,4R)-4-methyl-1,2-cyclohexanediamine(S,R,R-4m-chxn), and (1R,2S,4R)-4-methyl-1,2-cyclohexanediamine(R,S,R-4m-chxn), were prepared. The mixed-ligand complexes of the [PtXL]2+ type(X=(NH3)2, 1,2-ethanediamine, meso-2,3-butanediamine, and 2,3-dimethyl-2,3-butanediamine, L=each m-chxn) were synthesized and characterized by means of their electronic, circular dichroism, and 13C NMR spectra. The chelate ring formed by S,R,R-4m-chxn was almost conformationally fixed to take a δ conformation, while the chelate rings of 1 m-chxn, R,S,R-3m-chxn, and R,S,R-4m-chxn easily interchange between δ and λ conformations. The stereochemistries of these three complexes are attributable to the conformational requirements for both the cyclohexane ring and the chelate ring, for which synchronous inversions are presumed.
  • Kiyoshi Miyaji, Kenichi Morinaga
    1986 Volume 59 Issue 6 Pages 1695-1700
    Published: 1986
    Released: June 27, 2006
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    The enthalpies of transfer from water to mixtures with acetonitrile(ΔHt°) for various anions reach maxima at a mole fraction of acetonitrile(xAN)ca. 0.3, and decrease linearly and in parallel in the intermediate region. A linear relation is found between ΔHt° at xAN 0.3 and the hydration enthalpies for halide and symmetrical ions. This finding and the parallel xAN dependence of ΔHt° in the intermediate region are interpreted on the basis of the linear relation between the solvation enthalpies and the entropies for the halide ions. The reduction in the hydrogen-bonding interaction extending beyond the primary hydration sphere(ΔHINT) for halide ions in the mixtures is estimated based on a modified Eley and Evans hydration model. At xAN 0 to ca. 0.3, ΔHINT compared with that in water agree well with the observed ΔHt°, indicating that the increase in ΔHt° is due to the reduction in the outer hydration sphere interaction. However, they split’gradually at xAN above 0.3. The adequacy of the modifications in the treatment of the solvation enthalpy cycle in the mixtures is re-evaluated from the structural viewpoint. The exothermic change in the intermediate region may be attributable to the reduction in the cavity formation energy.
  • Frode Galsbøl, Masaaki Kojima, Toshio Ishii, Shigeru Ohba, Yosh ...
    1986 Volume 59 Issue 6 Pages 1701-1707
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Two of the five possible geometrical isomers of [RhCl2(edpp)2]+ were formed by reaction of RhCl3·2H2O with edpp (edpp=(2-aminoethyl)diphenylphosphine) in 1:2 molar ratio in ethanol. The chlorides of the isomers were separated by fractional crystallization from ethanol. The structures of the more soluble (main product) and the less soluble (minor product) complexes were determined by X-ray analyses to have the trans(Cl,Cl), cis(P,P) and cis(Cl,Cl), trans(P,P) configurations, respectively. Crystal data are: for trans(Cl,Cl), cis(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH, triclinic, space group P\bar1, with a=10.024(3), b=18.865(3), c=9.833(2) Å, α=97.66(1), β=103.92(2), γ=82.30(2)°, and Z=2, and for cis(Cl,Cl), trans(P,P)-[RhCl2(edpp)2]Cl·4H2O, triclinic, space group P\bar1, with a=11.341(4), b=17.780(6), c=8.712(3) Å, α=95.60(4), β=112.31(3), γ=82.56(4)°, and Z=2. The trans influence of the P atom on the Rh–N and Rh–P bond lengths is observed. The mean Rh–N and Rh–P bond lengths (2.125(4) and 2.300(1)Å) in the trans(Cl,Cl), cis(P,P) isomer are respectively longer and shorter than those of the cis(Cl,Cl), trans(P,P) isomer (2.078(12) and 2.336(3)Å). 13C NMR and absorption spectra of the isomers were recorded and are discussed.
  • Keiichi Tsukahara
    1986 Volume 59 Issue 6 Pages 1709-1712
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A compound containing both a hydroxyamino and a nitro group in a cobalt(III) cage complex was detected and isolated in a DQ\underset.+(1,1′-ethylene-2,2′-bipyridinium radical cation) reduction of the corresponding symmetric dinitro compound, [Co(diNOsar)]3+ (diNOsar=1,8-dinitro-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane). The nitro group of this compound was reduced to the hydroxyamino group by SO2, MDQ\underset.+(1,1′-ethylene-4,4′-dimethyl-2,2′-bipyridinium radical cation), and PDQ\underset.+(1,1′-trimethylene-2,2′-bipyridinium radical cation). Rate constants for the various processes were obtained.
  • Toyonobu Asao, Noboru Morita, J\={u}ro Ojima, Masamitsu Fujiyoshi, Kaz ...
    1986 Volume 59 Issue 6 Pages 1713-1721
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    5,10-Dimethy 1-6,8-bisdehydroheptatridecafulvalene 10, 10-methy 1-6,8-bisdehydro-4,5-benzoheptatridecafulvalene 11, 6,8-bisdehydro-4,5:10,11-dibenzoheptatridecafulvalene 12, 5,10-dimethyl-6,8-bisdehydroheptapentadecafulvalene 13, 5,10,15-trimethylheptapentadecafulvalene 14, 7,12-dimethylheptaheptadecafulvalene 15, and 7,12-dimethylheptanonadecafulvalene 16 were synthesized by a reaction of 8-oxoheptafulvene 8 with the corresponding bisdehydroannulenones 17. Dibenzo derivatives of 5,10-dimethyl-6,8-bisdehydropentatridecafulvalene 23, 10-methyl-6,8-bisdehydro-4,5-benzopentatridecafulvalene 24, 6,8-bisdehydro-4,5:10,11-dibenzopentatridecafulvalene 25, 5,10-dimethylpentapentadecafulvalene 26, 5,10,15-trimethylpentapentadecafulvalene 27, 7,12-dimethylpentaheptadecafulvalene 28, and 7,12-dimethylpentanonadecafulvalene 29 were also synthesized by the reaction of 9-fluorenylidenemethanone 21 with the corresponding annulenones 17. Furthermore, a benzoannelated series of heptapentadecafulvalenes 3035 was also synthesized. The 1H NMR spectra of these hepta- and dibenzopentafulvalenes are discussed in connection with their tropicity. It can be concluded that a slight polarization of π-electrons through pinch bonds from the seven-membered rings to the many-membered rings in the heptafulvalene system and from the many-membered rings to the five-membered rings in the pentafulvalene system exist regardless of the size of the many-membered rings.
  • J\={u}ro Ojima, Kazunori Itagawa, Tetsuya Nakada
    1986 Volume 59 Issue 6 Pages 1723-1731
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    5,10-Dimethyl-6,8-bisdehydropentatridecafulvalene 11, 10-methyl-6,8-bisdehydro-4,5-benzopentatridecafulvalene 12, 6,8-bisdehydro-4,5:10,11-dibenzopentatridecafulvalene 13, 5,10-dimethyl-6,8-bisdehydropentapentadecafulvalene 14, 7,12-dimethyl-8,10-bisdehydropentaheptadecafulvalene 15, and 7,12-dimethyl-8,10-bisdehy-dropentanonadecafulvalene 16 were synthesized through the reaction of the corresponding bisdehydroannulenones 16 with cyclopentadienide. The tropic nature of these pentafulvalenes is discussed on the basis of 1H NMR and electronic spectra as well as those of the corresponding heptafulvalene derivatives.
  • Hiroshi Nishino
    1986 Volume 59 Issue 6 Pages 1733-1739
    Published: 1986
    Released: June 27, 2006
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    The oxidation of naphthalenes with tris(2,4-pentanedionato)manganese(III) in acetic acid gave diacetylmethyl derivatives in good to moderate yields. Using excess amounts of the oxidant, the acetylmethyl-substituted naphthalenes were further oxidized and 3-acetoxy-3-naphthyl-2,4-pentanediones were obtained. The similar oxidation of anthracenes also produced (diacetylmethyl)anthracenes together with diacetylmethylene derivatives which were further oxidized. It was found that this direct diacetylmethylation was effective when the ionization potential of the aromatic compound was lower than 8.12 eV, and that the diacetylmethyl radical which was generated directly by the thermolysis of tris(2,4-pentanedionato)manganese(III) has an electrophilic nature based on the result of the oxidation of substituted naphthalenes. The reaction pathway for the oxidation of anthracene is also discussed.
  • Keiji Kobayashi, Hideyuki Tukada, Koichi Kikuchi, Isao Ikemoto
    1986 Volume 59 Issue 6 Pages 1741-1746
    Published: 1986
    Released: June 27, 2006
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    The hindered rotation about the C–N bond in dimethyldiselenocarbamates Me2N–CSe–SeR has been investigated by variable temperature NMR spectroscopy. The barrier to the rotation was almost independent of the partial structure of R (R=–Me, –CSe–NMe2), being 19 kcal mol−1* at around 93 °C. However, for bis(dimethylselenocarbamoyl) triselenide (R=–Se–Se–CSe–NMe2) (1), no splitting of N-methyl signals was observed in the 1H and 13C NMR spectra at subambient temperature. The equivalence of the methyl groups is discussed in terms of the bond switch between C=Se and C–Se moieties. The existence of the bond switch in 1 was also suggested by the XPS studies; the binding energy of the four selenium atoms was found to lie between those of C=Se and –Se–types of the selenium atoms, indicating that 1 takes an intramolecular coordination structure rather than a linear triselenide structure in the solid state, thereby facilitates the bond switch in solution.
  • Hidenori Chikashita, Kazuyoshi Itoh
    1986 Volume 59 Issue 6 Pages 1747-1752
    Published: 1986
    Released: June 27, 2006
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    The reduction of a variety of α,β-unsaturated carbonyl compounds, except for α,β-unsaturated aldehyde, to the corresponding saturated carbonyl compounds was effectively performed by using 1,3-dimethyl-2-phenylbenzimidazoline (DMBI) as a reducing agent with the aid of AlCl3. The reduction is discussed on the basis of the hydride-donating ability of DMBI, together with the role of AlCl3 as an electrophilic activator for the substrates. The catalytic efficiency of Lewis acids was found to be proportional to the efficiency to form a complex with a carbonyl group. The reduction of 2-cinnamoylpyridine with 2-deuterated DMBI revealed that in the reduction product, a deuterium atom was located at the β-position with respect to the carbonyl group. On the other hand, the reduction of the same substrate with DMBI followed by quenching with D2O gave a reduced product which contained a deuterium label at the α-position. These results were interpreted in terms of a mechanism involving an enolate intermediate produced by either a one-step hydride transfer or a sequential transfer of an electron (e) and a hydrogen atom (H·) from the reducing agent to the substrate.
  • Osamu Sakanaka, Takashi Ohmori, Shuji Kozaki, Tetsuo Suami, Toshio Ish ...
    1986 Volume 59 Issue 6 Pages 1753-1759
    Published: 1986
    Released: June 27, 2006
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    Ezomycins were discovered in a fermentation beer of Streptomyces species as antibiotics, which consisted of aminoocturonic acid, aminoglucuronic acid and base. As a part of a total synthesis of ezomycins, the title compounds have been synthesized. A KF-catalyzed Henry reaction between a nitropentose and a glyceraldehyde derivative gave a nitro alcohols mixture. Hydrogenation of the intact mixture, followed by N-acetylation afforded three diastereomers. The absolute configurations of the newly-introduced chiral centers were established by chemical methods and a X-ray crystal structure analysis.
  • Makoto Onaka, Motomitsu Kawai, Yusuke Izumi
    1986 Volume 59 Issue 6 Pages 1761-1765
    Published: 1986
    Released: June 27, 2006
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    Zeolite-promoted benzylation of alcohols with benzyl chloride has been investigated. By use of a series of cation-exchanged zeolites, which have the same crystalline structure but different acid and base properties, it is confirmed that the cooperative function of acid sites and base sites of zeolite is required for the effective benzylation of alcohols although both acid and base strengths are low. It is also found that alcohols show different reactivities in zeolite from those in solution depending on their molecular structures because the benzylation is promoted inside the narrow cavities of zeolite.
  • Misuzu Naora (nee Namikawa), Tatsushi Murae, Takahiko Tsuyuki, Takeyos ...
    1986 Volume 59 Issue 6 Pages 1767-1776
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    As authentic samples for identification of 29-norlanostane derivatives isolated from plant fossil, 29-norlanostan-24-one and -23-one, 29-norlanost-9(11)-en-24-one, -23-one, and -3-one, 29-norlanost-7-en-3-one, and 29-norlanostan-3-one were synthesized from a commercial lanosterol containing dihydrolanosterol.
  • Kazuhiro Maruyama, Seiji Tai, Hiroshi Imahori
    1986 Volume 59 Issue 6 Pages 1777-1780
    Published: 1986
    Released: June 27, 2006
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    2-Oxoalkylated 1,4-naphthoquinones were obtained in the photochemical reactions of 2,3-dichloro-1,4-naphthoquinone with 2-trimethylsiloxy-1-alkenes. Application of this method afforded a wide variety of functionalized 2-oxoalkylated 1,4-naphthoquinones. The photochemical reactions of 2,3-dichloro-1,4-naphthoquinone with 1-alkyl-2-(trimethylsiloxy)ethylenes gave naphthol derivatives. However, 1,1-dialkyl-2-(trimethylsiloxy)ethylenes gave none of products.
  • Mitsuo Sekine, Narihiro Masuda, Tsujiaki Hata
    1986 Volume 59 Issue 6 Pages 1781-1789
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Fully protected building units for oligodeoxyribonucleotide synthesis in the phosphoramidite approach were prepared in high yields by the 5′-dimethoxytritylation of N-[4,4′,4″-tris(benzoyloxy)trityl]deoxyribonucleosides followed by the 3′-phosphitylation with methoxymorpholinochlorophosphine. The solid phase synthesis of oligodeoxyribonucleotides on a controlled pore glass gel using the amidite units was examined. The efficiency of condensation was discussed in detail. The 4,4′,4″-tris(benzoyloxy)trityl (TBTr) group was removed rapidly from a protected tetramer synthesized on the controlled pore glass gel to give dGpCpApT.
  • J\={u}ro Ojima, Yasuhiro Yagi, Emiko Ejiri, Shuichi Ishizaka, Tadahito ...
    1986 Volume 59 Issue 6 Pages 1791-1799
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    14-Ethoxy-2,5,10-trimethyl-6,8-bisdehydroaza[14]annulene, 14-ethoxy-2-ethyl-5,10-dimethyl-6,8-bisdehydroaza[14]annulene, 2-ethoxy-3,11-dimethyl-5,6-benzo-7,9-bisdehydroaza[14]annulene, and 2-ethoxy-1 1,14-dimethyl-5,6-benzo-7,9-bisdehydroaza[14]annulene were synthesized. Influence of α-alkyl substitution and benzannelation upon the skeleton of the bisdehydroaza[14]annulene ring system is discussed on the basis of 1H NMR and UV spectra of these azaannulenes and their α-alkyl unsubstituted ones.
  • J\={u}ro Ojima, Yasuhiro Yagi, Sumio Manaka, Tetsuya Nakada, Yasunao S ...
    1986 Volume 59 Issue 6 Pages 1801-1807
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Syntheses of 2-ethoxy-3,6,11 -trimethyl-7,9-bisdehydroaza[16]annulene, 2-ethoxy-6,11,16-trimethyl-7,9-bis-dehydroaza[16]annulene, and 18-ethoxy-2,7,12-trimethyl-8,10-bisdehydroaza[18]annulene are described. It was found that the molecular skeletons of these α- or β-methylated aza[16]- and -[18]annulene are less planar than those of α- or β-methyl unsubstituted aza[16]- and aza[18]annulene, from examination of their 1H NMR and electronic spectra.
  • Otohiko Tsuge, Kazunori Ueno, Shuji Kanemasa, Kiyotaka Yorozu
    1986 Volume 59 Issue 6 Pages 1809-1824
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    N-(Cyanomethyl)- and N-(α-cyanobenzyl)imines derived from a variety of aldehydes and ketones can tautomerize into N-protonated azomethine ylides which undergo cycloadditions with olefinic dipolarophiles. These cycloadditions are often accompanied by the elimination of HCN, mostly in a stereospecific manner, showing these imines to be synthetic equivalents of nonstabilized nitrile ylides. Stereoselectivity of the cycloadditions is discussed.
  • Yoshinori Ihara, Yutaka Fukuda, Kozo Sone
    1986 Volume 59 Issue 6 Pages 1825-1827
    Published: 1986
    Released: June 27, 2006
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    Ten octahedral anionobis(C-substituted ethylenediamine)nickel(II) complexes were obtained by thermal reactions of corresponding diaqua salts, and their electronic and IR spectra were examined to see whether they are cis or trans. Most of them were found to be trans, but [Ni(NO3)(m-bn)2](NO3) and [NiCl2(i-bn)2] were cis.
  • Yutaka Tamaura
    1986 Volume 59 Issue 6 Pages 1829-1832
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    When solutions containing Fe(II), Ni(II), and SO42− ions were oxidized by a mixed gas of air and nitrogen at pH 7.1 (25 °C), a Ni(II)-bearing green rust II (GR-II), which is a uniform crystalline precipitate with a definite chemical composition, was formed. The Ni(II) content in the Ni(II)-bearing GR-II increased with an increase in the Ni(II) concentration in the reaction solution. The Ni(II)-bearing GR-II was spontaneously transformed into Ni(II)-bearing ferrite under a nitrogen atmosphere without any oxidant. The metal mole ratio of [Ni(II)/ Fe(III)]fer in the ferrite increased linearly with an increase in that of [Ni(II)/Fe(III)]grn in the Ni(II)-bearing GR-II (slope=0.193). From this relationship, the spontaneous transformation reaction was described as
    2(Ni2+)x(Fe2+)2−x(Fe3+)(SO42−)(OH)5→Ni0.39xFe3−0.39xO4+(2−1.61x)Fe2++1.61xNi2++Fe(OH)2+2SO42−+4H2O.
    This equation shows that Fe(II) ion in the GR-II is more readily incorporated into the ferrites than Ni(II) ion.
  • Tadashi Hara, Takashi Ebuchi, Akihiro Arai, Masakatsu Imaki
    1986 Volume 59 Issue 6 Pages 1833-1838
    Published: 1986
    Released: June 27, 2006
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    Since the catalytic activity of copper(II) for the chemiluminescent reaction between 1,10-phenanthroline and hydrogen peroxide decreased in the presence of protein, this phenomenon was applied to the determination of protein. The determination of protein was carried out by a flow-injection method, and the conditions for the determination of protein were established. The catalytic activity of copper(II) was enhanced by using an amino acid instead of the conventional biuret reagent. Similar calibration curves were obtained for human serum albumin, bovine serum albumin, human serum γ-globulin, bovine serum γ-globulin, and ovalbumin. According to the present flow-injection method using a chemiluminescent reaction, a small amount of protein could be conveniently and economically determined over a wide range of concentrations, 5.0×10−6 g dm−3–1.0×10−1 g dm−3 at the rate of about 20 samples per hour, with the detection limit of 250 pg as the injected amount and the coefficient of variation of 5.9% (n=9). The sensitivity of the present method was about 40 times that of the previous luminol-hydrogen peroxide system.
  • Yoshihisa Matsuda, Toshihiko Takaki, Yukito Murakami
    1986 Volume 59 Issue 6 Pages 1839-1844
    Published: 1986
    Released: June 27, 2006
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    Photochemical reduction of oxomolybdenum(V) complexes of 5,10,15,20-tetra-p-tolylporphine, [Mov(X)(ttp)], was investigated under irradiation with the visible light in benzene, where X stands for an axial ligand placed trans to the oxo group. Irradiation of [MovO(X)(ttp)] resulted in a homolytic cleavage of the Mo–X bond to afford [MoIVO(ttp)] and a radical species generated from the axial ligand (X). The reduction rate was controlled by the nature of the Mo–X bond, and a complex with less ionic character of the axial bond was more reactive in the homolysis process. The bulkiness of the axial alkoxo ligands may provide two different effects which are opposite to each other on the reactivity: (i) The repulsive interaction between an axial ligand and the equatorial ttp accelerates the homolysis of the Mo–X bond; (ii) the diffusion rate of the radical species, generated by the photochemical cleavage of the axial coordinate bond, from the coordination sphere is progressively retarded as the bulkiness of the alkoxo ligand increases. The second effect seems to be more pronounced for the present photochemical reaction. The photochemical reduction of [MoVO(X)(ttp)] is essentially composed of two sequential steps, photochemical cleavage of the Mo–X bond and diffusion of the radical species from the coordination sphere. Reoxidation of [MoIVO(ttp)] under aerobic irradiation conditions afforded [MoVO(OH)(ttp)] and [(MoVO(ttp))2O] via the postulated intermediate formation of [MoV(OO·)(ttp)].
  • Joichi Ueda, Natsuko Yamazaki
    1986 Volume 59 Issue 6 Pages 1845-1848
    Published: 1986
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Using the coprecipitation method with hafnium hydroxide, the flameless atomic-absorption spectrometric and the differential-pulse polarographic determinations of cadmium have been studied. The collecting ability of hafnium hydroxide for cadmium is excellent; from 0.01 to at least 1000 μg of cadmium in 50–400 cm3 of a sample solution is coprecipitated quantitatively. The presence of hafnium hydroxide does not interfere with either method of determining cadmium. Of the diverse ions examined, there are no ions which interfere with the flameless atomic-absorption spectrometric determination, even if they are present in a concentration of at least 5000 times that of cadmium; as for the differential-pulse polarographic determination, only indium interferes when present in small amounts. The linear calibration curves through the point of origin were obtained over the range of 0.4–4 ng cm−3 of cadmium for the former method and 0.04–40 μg cm−3 for the latter method. In the proposed methods, the flameless atomic-absorption spectrometric determination was successfully applied to the analysis for trace amounts of cadmium in river-water samples.
  • Takayuki Komatsu, Minoru Ohira, Masaaki Yamada, Shigetaka Suzuki
    1986 Volume 59 Issue 6 Pages 1849-1855
    Published: 1986
    Released: June 27, 2006
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    Ultrasonic irradiation of alkaline luminol solution produces intense light emission (sonic chemiluminescence) as a result of the reaction of luminol with reactive species which are generated ultrasonically from water molecule. For the analytical application of ultrasound-induced luminescence, the sonic chemiluminescence of luminol is first utilized for the determination of ultratraces of cobalt(II) by flow injection and continuous flow methods. This novel method is based on the measurement of sonic chemiluminescence enhanced by the presence of cobalt(II); it provides analytical characteristics comparable to those for the conventional luminol chemiluminescence method using hydrogen peroxide as an oxidizing agent. The limit of detection is 0.06 pg(10-μl sample injection) or 0.06 pg ml−1 (continuous sample flow), the linear dynamic range is 3 orders of magnitude (10-μl sample injection), the sampling rate is 120 h−1, and the relative standard deviation is 3.9% for 6 pg Co(II) (n=10). The method is successfully applied to real samples. Possible explanation of sonic chemiluminescence is also presented; the mechanism involving superoxide anion radical is proposed for the cobalt(II)-catalyzed sonic chemiluminescence.
  • Setsuko Kudo, Akio Iwase
    1986 Volume 59 Issue 6 Pages 1857-1861
    Published: 1986
    Released: June 27, 2006
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    The electrolyte effect on the homogeneous chemical equilibria of Ni(bfac)2, Ni(ftac)2, and Ni(ttac)2 in dimethyl sulfoxide has been studied by means of polarographic and ultraviolet spectral measurements, where bfac, ftac, and ttac represent the enolate anions of benzoyltrifluoroacetone, 2-furoyltrifluoroacetone, and 2-thenoyltrifluoroacetone respectively. The chemical equilibria of these complexes in 0.05 mol dm−3 TBAP solutions found previously:
    Ni(bi-L)2\ ightleftharpoonsNi(bi-L)(uni-L)\ ightleftharpoonsNi(bi-L)++L\ ightleftharpoonsNi(uni-L)++L
    shifted more to the right in the presence of one of the electrolytes (NaClO4, KClO4, RbClO4, CsClO4, TMAP, or TEAP) at the same concentrations as TBAP; bi- and uni- mean that the ligands coordinate to the metal as bidentate and unidentate respectively. Under the conditions of [NiL2]=1 mmol dm−3 and [MClO4]=0.05 mol dm−3, the molar fractions of the species of the Ni(bi-L)2 type decreased with an increase in the inverse of the cationic radii. Such a tendency was explained mainly in terms of the interaction between the π-electron system of Ni(bi-L)2 and those cations. For the same metal perchlorates, except NaClO4, the stability of Ni(bi-L)2 decreased in the order of: bfac>ftac>ttac.
  • Kikuo Terada, Madoka Hamano, Kazuhisa Komura, Ken Matsumoto
    1986 Volume 59 Issue 6 Pages 1863-1868
    Published: 1986
    Released: June 27, 2006
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    The distribution and characterization of 137Cs in shallow water sediments are investigated. The concentration of 137Cs in surface sediments which have been collected from the 10–20 m depth of Tsukumo Bay, Noto Peninsula, tends to decrease with an increase in the distance from the inner part of the bay to the outer part. Vertically, 137Cs contents gradually decrease to the 10 cm depth and then steeply decrease beyond this depth, until at the 15 cm depth no activity is observed. A sequential extraction technique with several kinds of extractants has been employed to survey the chemical form of the nuclide in the sediments. 137Cs is completely extracted with an ammonium nitrate solution suggesting that the nuclide is strongly adsorbed in the crystal lattice of some clay minerals and is exchangedly desorbed from the sediment phase by ammonium ions in a high concentration. A core sample has been elutriated in five components of different grain sizes, and the contents of sodium, potassium, and 137Cs have been determined. It has been revealed that a unit amount of the finest component contains about three times as much of the nuclide as that of the coarsest one. On the contrary, the potassium contents slightly decrease with the decrease in the particulate size.
  • Shuji Kanemasa, Hirohiko Sakoh, Eiji Wada, Otohiko Tsuge
    1986 Volume 59 Issue 6 Pages 1869-1876
    Published: 1986
    Released: June 27, 2006
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    A cross-conjugated triene, trans-3-methylene-1,4-hexadiene, is accessible from the Grignard reagent of chloroprene and methyloxirane via 1-methyl-3-methylene-4-pentenyl tosylate. The diene-transmissive Diels–Alder reaction of the triene and the stepwise sequence of double Diels–Alder reaction of the tosylate are investigated. Stereo- and regioselectivity of these reactions in the presence or absence of Lewis acid catalyst are discussed.
  • Tadashi Suehiro, Seiichi Masuda, Takaaki Tashiro, Ryuichi Nakausa, Mas ...
    1986 Volume 59 Issue 6 Pages 1877-1886
    Published: 1986
    Released: June 27, 2006
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    Aryldiazenyl radicals were formed at −104–−116°C by photoirradiation of cyclopropane solutions of 1-aryl-2-(arylthio)diazenes and of l-aryl-3,3-dimethyltriazenes in the presence or absence of olefins, and also by irradiation of cyclopropane solutions of substituted 1,2,3-benzothiadiazoles in the presence of di-t-butyl peroxide. The ESR spectra were analyzed and the hfs constants were assigned by reference to the spectra of methyl, 2H, and 15N-labelled aryldiazenyl radicals and to the results of CINDO calculations. Aryldiazenyl radicals are relatively persistent and the –N=N group rotates about the C–N2 bond axis. The preferred conformations of the radicals were considered.
  • Katsumi Fujimoto, Yuji Iwano, Koichi Hirai
    1986 Volume 59 Issue 6 Pages 1887-1896
    Published: 1986
    Released: June 27, 2006
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    An effective method for (R)-1-hydroxyethylation of benzyl bis(phenylseleno)penicillanate is described. The hydroxyethylated product was transformed into the 4-methylsulfonyl- and 4-phenylsulfonyl-2-azetidinone derivatives. These monocyclic compounds were reacted with potassium cyanide under two-phase conditions to give the 4-cyano-2-azetidinone derivative (C1-unit introduction) in high yield. The cyano group was then converted into the iodomethyl group. Using the 4-iodomethyl-2-azetidinone derivative an isopenam derivative was synthesized. Furthermore, carbapenam derivative were also constructed by a novel [3+2] cyclization reaction between 4-iodomethyl-2-azetidinone and dimethyl 2-methylthio- and 2-phenylthiofumarate.
  • Mitsuaki Kodama, Usman S. F. Tambunan, Tetsuto Tsunoda, Shô It&o ...
    1986 Volume 59 Issue 6 Pages 1897-1900
    Published: 1986
    Released: June 27, 2006
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    (−)-Vitrenal, the enantiomer of the natural sesquiterpene aldehyde isolated from a liverwort, has been synthesized starting from (+)-3-carene, and its activity as a plant-growth regulator has been tested.
  • Yasuji Ihara, Eiji Nakanishi, Mamoru Nango, Joichi Koga
    1986 Volume 59 Issue 6 Pages 1901-1905
    Published: 1986
    Released: June 27, 2006
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    The rate constants for hydrolysis of the enantiomers of amino acid nitrophenyl esters have been determined at pH 9.00 and pH 10.0 in the presence of α- or β-cyclodextrin. α- and β-Cyclodextrins cause stereoselective acceleration in the hydrolysis of m-substituted enantiomers. On the other hand, less stereoselectivity is observed in the hydrolysis of p-substituted enantiomers. The stereoselective properties are discussed in the light of cyclodextrin-ester dissociation constants and thermodynamic parameters of the reaction.
  • Shinobu Itoh, Yutaka Kitamura, Yoshiki Ohshiro, Toshio Agawa
    1986 Volume 59 Issue 6 Pages 1907-1910
    Published: 1986
    Released: June 27, 2006
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    Kinetic studies on the oxidative deamination of amines by coenzyme PQQ are carried out under anaerobic conditions. The reaction is first-order in the appearance of the reduced PQQ and in the total amine concentrations. A large kinetic isotope effect (kHkD=7.24) in the oxidation of α,α-dideuteriobenzylamine indicates that the C–H bond cleavage is a rate-determining step. From the results of formation of two types of reduced PQQ (quinol and aminophenol) and low reactivities of secondary and tertiary amines, we propose the mechanism via covalent addition of the amine to the quinone followed by rate-limiting α-proton removal.
  • Shinobu Itoh, Yoshiki Ohshiro, Toshio Agawa
    1986 Volume 59 Issue 6 Pages 1911-1914
    Published: 1986
    Released: June 27, 2006
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    Reduced PQQ (PQQH2) is prepared by the reaction of PQQ with thiophenol, 1-benzyl-1,4-dihydronicotinamide (BNAH), sodium dithionite, or sodium borohydride. Oxidation of PQQH2 to PQQ by molecular oxygen in aqueous solutions is investigated kinetically. The oxidation is accelerated gradually with proceeding of the reaction, which may be attributed to the side reaction of PQQH2 and H2O2 produced by the reaction of PQQH2 and O2. As in fact, the yield of H2O2 is found to be 50% based on PQQH2. Initial rate is first-order in oxygen concentration. The pH-rate profile suggests that an active species in the reaction is PQQH. Autocatalysis of O2\ ewdot and PQQ itself is scarcely detected in this reaction. The mechanism of the oxidation is also discussed.
  • Kaoru Okamoto, Tadao Kondo, Toshio Goto
    1986 Volume 59 Issue 6 Pages 1915-1919
    Published: 1986
    Released: June 27, 2006
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    2-Amino-3,4-dihydro-4-oxo-7-(β-D-arabinofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine-5-carboxylic acid, an analogue of cadeguomycin, has been synthesized via glycosylation of 3-methoxymethyl-5-methyl-2-methylthio7H-pyrrolo[2,3-d]pyrimidin-4(3H)-one with 2,3,5-tri-O-benzyl-D-arabinofuranosyl chloride.
  • Sei Tsuboyama, Tosio Sakurai, Kaoru Tsuboyama, Kozo Doi
    1986 Volume 59 Issue 6 Pages 1921-1924
    Published: 1986
    Released: June 27, 2006
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    The molecular structure of naematolin 3-p-bromobenzoate has been determined by X-ray diffraction analysis. Unlike known caryophyllene derivatives isolated so far, the stereochemistry of the ring juncture is cis (1S,9S) form. The absolute configurations of five chiral centers of this compound are 1S,2S,3R,6R, and 9S, and the geometry of endocyclic double bond is E mode. This is the first example of a cis-fused 1S,9S-caryophyllane sesquiterpenoids confirmed by X-ray structure determination. Crystal data and the final R factor are: Mr=491.36, orthorhombic, space group P212121, a=10.650(2), b=20.650(6), c=10.526(2) Å, U=2315(1) Å3, Z=4, Dc=1.410 Mg m−3, μ=1.791 mm−1, R=0.084 for 1666 observed unique reflections.
  • Masayuki Nakagaki, Shoko Yokoyama
    1986 Volume 59 Issue 6 Pages 1925-1930
    Published: 1986
    Released: June 27, 2006
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    Base-catalyzed hydrolysis of acetylcholine chloride (Ach) in the presence of anionic and nonionic surfactants was investigated. The rate of hydrolysis was determined by measuring the rate of disappearance of Ach with a spectrophotometer. At a constant pH of 9.0, addition of heptaethylene glycol dodecyl ether (HED) at concentrations above the critical micelle concentration (cmc) results in a slight increase in the apparent rate, υ, which is expressed by two reaction rates, υf and υm, in the aqueous and micellar phases, respectively. The increase in the apparent rate is due to increase in υm. In the presence of sodium dodecyl sulfate (SDS), the apparent rate constant, kapp, is approximately constant at concentrations below the cmc, and kapp decreases above the cmc. In the presence of SDS–HED mixed micelles, kapp decreases with the mole fraction of SDS. In these cases, the decrease in the apparent rate is due to the decrease in both υf and υm. These two kapp decreases are due, respectively, to the decrease in Ach in the aqueous phase and the electrostatic repulsion between OH and DS at the micelle surface in conformity with the Gouy-Chapman theory.
  • Susumu Okazaki, Hirofumi Jouhouji
    1986 Volume 59 Issue 6 Pages 1931-1936
    Published: 1986
    Released: June 27, 2006
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    Vapor phase-isomerization of o-chlorotoluene was somewhat promoted by H-mordenite (HM). The catalytic activity was appreciably enhanced by treatment with CF3Cl and other chlorofluorocarbons such as CF2ClCF2Cl and CF2ClCF3. In particular, maintenance of the HM catalyst activity was remarkably improved by CF3Cl treatment. The CF3Cl-treated HM also promoted vapor phase isomerizations of p- and m-chlorotoluene. The catalytic activity was relatively long-lasting for the isomerization of p-chlorotoluene. Enlargement of the HM pore size on treatment with CF3Cl and other chlorofluorocarbons may contribute to increasing the catalytic activity and then maintaing it.
  • Kosaku Suga, Shigeru Aoyagui
    1986 Volume 59 Issue 6 Pages 1937-1939
    Published: 1986
    Released: June 27, 2006
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    Cyclic voltammograms of p-benzoquinone and its methyl derivatives are measured in a strongly alkaline aqueous solution. All of them have shown one reversible or quasi-reversible wave corresponding to the reduction of the quinones. Except for the 2,3,5,6-tetramethyl-p-benzoquinone (duroquinone), they have all also shown one or two additional small waves corresponding to the reduction of the OH adducts of the quinones. Their main waves can reasonably be explained by the calculated values of E1° and E2°, which have been determined by the two-electron reduction potential and the several equilibrium constants of the quinones. The differences in the E1° and E2° values for these quiones are very small (0.007–0.046 V) in contrast to those in an aprotic solvent.
  • Yukio Yoshida, Sadakatsu Nishikawa
    1986 Volume 59 Issue 6 Pages 1941-1945
    Published: 1986
    Released: June 27, 2006
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    Ultrasonic absorption has been measured in an aqueous solution of s-butylamine over the frequency range 6.5–220 MHz and the concentration range 0.0115–3.18 mol dm−3 at 25 °C. The single relaxational phenomenon observed in a range less than 1 mol dm−3 was found to be associated with a perturbation of the equilibrium; R-NH3++OH (Remark: Graphics omitted.) R-NH3+···OH. The rate constants of the forward and backward reactions, k12 and k21, have been determined to be 2.1×1010 s−1 mol−1 dm−3 and 1.8×108 s−1, respectively. It was also determined that the next step, R-NH3+···OH (Remark: Graphics omitted.) R-NH2+H2O, which had been thought to have a considerable influence on the first step, was not very effective regarding the ultrasonic absorption observed in the MHz frequency range. The equilibrium constant in the second step, K32, has been determined to be 3.5×10−2. The standard volume change of the reaction has been calculated to be 26 cm3 mol−1 from the concentration dependence of the maximum excess absorption per wavelength. The relaxation observed in a range greater that 1 mol dm−3 has been estimted to be associated with a molecular aggregation reaction. An ultrasonic study in an aqueous solution of butylamine has also been performed in order to determine the rate constants associated with a proton-transfer reaction at 25 °C.
  • Shin-ichi Ohno, Katsutoshi Furukawa, Takeshi Soga
    1986 Volume 59 Issue 6 Pages 1947-1951
    Published: 1986
    Released: June 27, 2006
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    Decomposition of crystalline potassium nitrate due to He+-, Ar+-, and Xe+- ion bombardment was studied in the energy range from 20 to 100keV. The cross sections for producing nitrite ions were for the first time determined to be 5.7×10−20m2, 12.6×10−20, and 22.0×10−20m2 for 100keV He+, Ar+, and Xe+ ion, respectively. Comparing the values of these cross sections with the rate of an elastic and inelastic energy loss of these incident ions, which were calculated on the basis of the theory of Lindhard et al., it may be concluded that inelastic energy is about five times more efficient than elastic energy for the decomposition of the solid potassium nitrate.
  • Hiroshi Sasaki, Akihiko Ueno, Jun-ichi Anzai, Tetsuo Osa
    1986 Volume 59 Issue 6 Pages 1953-1956
    Published: 1986
    Released: June 27, 2006
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    Benzocrown ether-linked spirobenzopyran (1) and its analogue (2) which has no crown ring were synthesized. The binding abilities of 1 for alkali metal cations (Na+, K+, Rb+, Cs+) were found to change by UV light irradiation, while 2 did not bind these cations before and after UV light irradiation. The plasticized poly(vinyl chloride) (PVC) membrane entrapping 1 or 2 showed photoinduced potential changes reversibly by UV and visible light irradiation. In the membranes of both 1 and 2 showed normal photochromism of spirobenzopyran. In the case of 1, the magnitude of the photoinduced potential change depended upon kind and concentration of alkali metal cations. However, the magnitude of photoinduced potential change of the membrane entrapping 2 was hardly affected by kind and concentration of alkali metal cations. The results are explained in terms of cooperative action of both crown ether and spiropyran.
  • Ryoko Tabeta, Misako Aida, Hazime Saitô
    1986 Volume 59 Issue 6 Pages 1957-1966
    Published: 1986
    Released: June 27, 2006
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    We have recorded static and magic angle spinning (MAS) 23Na NMR spectra of a variety of inorganic salts, solvent complexes, and complexes with small ligand molecules and ionophores in the solid state, in order to obtain the 23Na chemical shifts of the ion–ion, ion–solvent, and ion–ligand interactions, respectively. In all cases, MAS resulted in considerable reduction of the linewidths. The observed 23Na chemical shifts were corrected by subtracting the displacements by the quadrupole interaction when the quadrupole coupling constants cannot be ignored. We found that the range of the 23Na chemical shifts found in the solid state is about 60 ppm and the 23Na chemical shift of NaBPh4 appears at the highermost region (−52 ppm). The 23Na NMR chemical shifts of these complexes exhibited their characteristic peak positions, depending on variety of ligand molecules (H2O, ether, or carbonyl) and Na–O interatomic distances but independent of the type of counterion. Finally, an attempt was made to relate the 23Na chemical shifts to the magnitude of electron transfer from the ligand molecules to 3p orbital of Na+ ion, by means of an ab initio molecular orbital method.
  • Yoshiharu Matsuda, Masayuki Morita, Fumitsugu Tachihara
    1986 Volume 59 Issue 6 Pages 1967-1973
    Published: 1986
    Released: June 27, 2006
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    Electrolytic conductivities of LiClO4 and LiPF6 have been investigated in the mixed systems of the high permittivity solvents and low viscosity solvents. Propylene carbonate (PC), sulfolane (S), and dimethyl sulfoxide (DMSO) were used as the high permittivity solvents, and 1,2-dimethoxyethane (DME) and tetrahydrofuran (THF) as the low viscosity solvents. The conductivity of 1 mol dm−3 LiClO4 has a miximum in the mixed solvent with 40–80 m/o ether for every system. The conductance improvement by solvent-blending was qualitatively described in terms of a favorable combination of high permittivity and low viscosity of each component. The maximum conductivity of 1 mol dm−3 LiClO4 increased in the order of S<PC<DMSO for the systems containing THF. The difference in the order of maximum conductivity between DME and THF was interpreted by ion-solvent interactions, whose measure is generally expressed by the donor and acceptor properties of the solvent. The LiPF6 solutions had much higher conductance than those of LiClO4, especially in high DME concentration regions.
  • Harumichi Kobashi, Tadashi Okada, Noboru Mataga
    1986 Volume 59 Issue 6 Pages 1975-1979
    Published: 1986
    Released: June 27, 2006
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    Mechanism and kinetics of hydrogen atom transfer reaction from mesitylene (M) to triplet chloranil (3CA) in 1,2-dichloroethane (DCE) at room temperature have been studied by means of picosecond (ps) and nanosecond (ns) laser flash photolysis techniques. It was found that the hydrogen transfer resulting in the formation of chloranil semiquinone radical (CAH·) proceeded through a partial charge-transfer (CT) triplet complex between 3CA and M as an intermediate. No ion-pair formation was observed. The triplet complex showed transient absorption bands in the visible and near infrared regions. The association constant (KT=28 dm3 mol−1) and lifetime (τC=32 ns) of the complex were estimated from a kinetic analysis for 3CA quenching. From these results, combined with those of the quantum yield of CAH· formation, the first order rate constants for the hydrogen transfer and intersystem crossing in the triplet complex were estimated to be (1.7 and 1.4)×107 s−1, respectively.
  • Setsuko Sato, Ryuichi Ikeda, Daiyu Nakamura
    1986 Volume 59 Issue 6 Pages 1981-1989
    Published: 1986
    Released: June 27, 2006
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    The temperature dependences of 1H spin-lattice relaxation times were determined at 20 MHz for [(CH3)4N]2CdCl4, [(CH3)4N]2CdBr4, and [(CH3)4N]2CdI4. For the last two complexes, the frequency dependence of the relaxation time was observed above room temperature. 1H NMR second moments were observed for the bromide complex. At room temperature, the first two complexes were found to be isomorphous with the iodide complex which forms orthorhombic crystals. Differential thermal analysis experiments revealed that these complexes undergo four, one, and one solid-solid phase transitions in the above order between ca. 80 and 430 K. Two 1H T1 minima were clearly observed at lower temperatures for the chloride and bromide complexes, whereas at least three 1H T1 minima partly overlapped with each other were detected at lower temperatures for the iodide complex. For the former two complexes, the 1H T1 data were well analyzed by the general method already reported. For the bromide and iodide complexes, 1H T1 curves observed showed a maximum above room temperature. Motions of the cation activated in these complexes are discussed in relation to the crystal field experienced by the cation.
  • Takeshi Sakaizumi, Kazuyuki Iida, Osamu Ohashi, Ichiro Yamaguchi
    1986 Volume 59 Issue 6 Pages 1991-1995
    Published: 1986
    Released: June 27, 2006
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    The microwave spectra of two isotopic species (80Se and 78Se) of ethyl isoselenocyanate were measured in the frequency region of 10–28 GHz. Only a-type R-branch transitions in the ground vibrational state were identified. The rotational constants in MHz were obtained; A=15140±23, B=1090.443±0.016, and C=1029.261±0.016 for 80Se species and A=15112±28, B=1099.865±0.012, and C=1037.745±0.012 for 78Se species. The plausible structure of ethyl isoselenocyanate has deduced from the observed rotational constants to be the synperiplanar form with a plane of symmetry.
  • Yutaka Nigara, Bernard Cales
    1986 Volume 59 Issue 6 Pages 1997-2002
    Published: 1986
    Released: June 27, 2006
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    The direct thermal decomposition of carbon dioxide CO2 to produce carbon monoxide CO have been studied as a mean of conversion and storage of a thermal energy, such as the solar heat, into a gaseous fuel. The process under investigation consists to displace the dissociation equilibrium of carbon dioxide by a selective pumping of oxygen at high temperature through a semipermeable membrane. Large amounts of carbon monoxide have been produced after the extraction of the oxygen arising from the CO2 dissociation with the aid of a membrane made of calcia-stabilized zirconia. The variations of the flow of CO evolved from the reactor vs. temperature and oxygen partial pressure are in good agreement with the theoretical variations that may be deduced from the general equations of electrochemical transport in stabilized zirconia. Thereby, the efficiency of this process appears to be directly limited by the low oxygen permeation rate through the material used as oxygen selective membrane.
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