Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 53 , Issue 8
Showing 1-50 articles out of 72 articles from the selected issue
  • Katsuomi Takehira, Takashi Hayakawa, Toshio Ishikawa
    1980 Volume 53 Issue 8 Pages 2103-2110
    Published: 1980
    Released: April 19, 2006
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    The liquid-phase decomposition of t-butyl hydroperoxide (t-BuOOH) has been carried out in benzene under an N2 atmosphere using a vanadium or chromium oxide, supported on γ-Al2O3 or SiO2 as the catalyst, for the purposeof clarifying the reaction mechanism of the cyclohexene oxidation. The decomposition of t-BuOOH on the supported oxide catalyst was a first-order reaction; the main products were t-butyl alcohol, di-t-butyl peroxide, and acetone, suggesting that t-BuOOH is decomposed homolytically on the catalyst by the Haber-Weiss mechanism. The effect of the vanadium–chromium binary system formation was small, but the interaction between metal oxides and the supports appeared to be important in the t-BuOOH decomposition. Tetrahedrally co-ordinated vanadium species were formed on SiO2 and showed the highest activity, followed by the chromium co-ordinated tetrahedrally on SiO2 or on γ-Al2O3, while an octahedrally co-ordinated vanadium or chromium showed low activity. Such order of the activity was in good agreement with that obtained in the liquid-phase oxidation of cyclohexene. We observed a relatively good correlation between the catalytic activity and the acidity of the supported binary metal oxides. The V2O5–SiO2 system showed an especially large acidity; here t-butyl alcohol was dehydrated into di-t-butyl ether and 2-methyl propene.
  • Midori Goto, Eiichi Asada
    1980 Volume 53 Issue 8 Pages 2111-2113
    Published: 1980
    Released: April 19, 2006
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    The A′-form of tridecanoic acid is triclinic, with the space group P\bar1 and with a=4.273(1), b=4.972(1), c=37.69(1) Å, α=90.36(2), β=109.44(2), and γ=112.43(2)°. The structure was determined by the Patterson method. Refinement by block-diagonal least-squares methods gave a final R factor of 0.071.
  • Kooji Tajima, Fumiaki Kai, Tetsuo Kawahara
    1980 Volume 53 Issue 8 Pages 2114-2119
    Published: 1980
    Released: April 19, 2006
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    The solubilities of methylmercury(II) chloride (MMC), methylmercury(II) bromide (MMB), methylmercury(II) iodide (MMI), ethylmercury(II) chloride (EMC), and ethylmercury(II) bromide (EMB) in water have been determined over the temperature range of 10–55 °C (20–40 °C for MMC and EMC). The temperature dependence of the solubilities expressed as mole fractions x2 was given by the following equations:
    & logx_2(MMC)=-1059/T+0.176 (20–40°C)
    & logx_2(MMB)=-1094/T-0.263 (10–55°C)
    & logx_2(MMI)=-463/T-3.246 (10–25°C)
    & logx_2(MMI)=5.498×10^6(1/T)^2-3.711×10^4(1/T)+57.814 (25–55°C)
    & logx_2(EMC)=-1048/T-0.612 (20–40°C)
    & logx_2(EMB)=-179/T-4.293 (10–25°C)
    & logx_2(EMB)=5.389×10^6(1/T)^2-3.603×10^4(1/T)+55.322 (25–55°C)
    The thermodynamic parameters for the transfer process from solid to saturated aqueous solution were also determined.
  • Wataru Inaoka, Shoji Harada, Tatsuya Yasunaga
    1980 Volume 53 Issue 8 Pages 2120-2122
    Published: 1980
    Released: April 19, 2006
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    The dimerization reaction of dye, Rhodamine 6G, in aqueous solution was studied spectrophotometrically and kinetically: the equilibrium constant and the rate constants were found to be K=1.6×103 M−1, kf=1.1×109 M−1 s−1, and kb=7.0×105 s−1, respectively, at 15 °C. These rate constants, and those of other dyes are discussed. The effect of the ionic strength was also studied.
  • Isao Kojima, Makoto Kiyomiya, Iwao Yasumori
    1980 Volume 53 Issue 8 Pages 2123-2127
    Published: 1980
    Released: April 19, 2006
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    The thermal desorption of hydrogen adsorbed on a clean surface of polycrystalline copper foil was studied under ultra high vacuum conditions. The presence of chemisorbed hydrogen in a dissociated state was verified in a temperature range between 193 and 573 K. During the desorption process, the adsorbed hydrogen atoms recombined into molecules; this follows second order kinetics. The activation energy for desorption was 68.6±8.0 kJ mol−1 and remained nearly constant in the range of surface coverage up to 1.6×1014 atom cm−2. The isotope effect on the desorption of deuterium was found to be straightforward. These findings showed a good agreement with the results obtained from the analysis of H2–D2 equilibration on copper powder catalyst. In addition, the necessary conditions to obtain the exact desorption spectra were inspected with the aid of computer simulation.
  • Kunimistu Morishige, Shigeharu Kittaka, Tetsuo Morimoto
    1980 Volume 53 Issue 8 Pages 2128-2132
    Published: 1980
    Released: April 19, 2006
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    The structure of the adsorbed layer of water on SnO2 was investigated by means of thermal desorption, water physisorption, and electron diffraction, using four kinds of SnO2 samples which differ in method of preparation. Two distinct peaks appear around 513 and 573 K in the thermal-desorption spectra. The peak around 513 K is due to the condensation dehydration of hydroxyls on the (100) plane of SnO2, on which the two-dimensional condensation of water occurs. The peak around 573 K is associated with that on the (101) plane, on which the physisorption of water is strong and the two-dimensional condensation of water does not occur. The portion of the (100) plane occupied by water molecules is relatively small, and the 1 : 4 ratio (H2O : OH) holds also on the surfaces on which the two-dimensional condensation of water does not occur. In conclusion, the fully hydroxylated surfaces of SnO2 are hydrophobic in the sense that they sparsely adsorb water molecules.
  • Osamu Kondo, Ko Saito, Ichiro Murakami
    1980 Volume 53 Issue 8 Pages 2133-2140
    Published: 1980
    Released: April 19, 2006
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    The thermal decomposition of methyl chloride diluted in Ar has been studied behind shock waves over the temperature range between 1680 and 2430 K and the total density range of 2.0×10−6–3.5×10−5 mol cm−3. The decomposition rate was monitored by means of the UV absorption of the CH3 radical produced. The initiation reaction was found to be the C–Cl bond fission; the process proceeded in the fall-off region under the present experimental conditions. From the fall-off data, low- and high-pressure rate constants (k0/[Ar] and k) were obtained by the application of a refined RRKM theory involving a weak collision effect. Thus, the Arrhenius expressions were given as:
    & k_0/[Ar]=10^15.56 exp(-247 kJ mol^-1/RT) cm^3 mol^-1 s^-1,
    & k_∞=10^13.86 exp(-383 kJ mol^-1/RT) s^-1.
    The collision efficiency factor, βc, was obtained as 0.02 at the mean temperature of the experiment by comparing the low-pressure rate constant with the strong collision-rate constant. The high-pressure rate constant was well explained by the maximum free-energy criterion presented by Quack and Troe.
  • Gunzi Saito, John P. Ferraris
    1980 Volume 53 Issue 8 Pages 2141-2145
    Published: 1980
    Released: April 19, 2006
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    Current theories on the origin of high electrical conductivity in TCNQ-based materials emphasize the need for incomplete charge transfer as well as segregated stacks of donor and acceptor molecules and uniform spacing within the stacks. The requirements for an “organic metal” are discussed in terms of partial charge transfer. An examination of 61 structurally related TTF–TCNQ, based complexes suggests that the combinations with the redox potential −0.02≤E1(D)−E1(A)≤0.34 V have a high possibility of being “organic metals.” A method to arrange the complex by the difference between the electrochemical half-wave potentials of the donor and the acceptor molecule is proposed to predict electrical properties of the complex.
  • Yukio Matsuoka, Kiwamu Yamaoka
    1980 Volume 53 Issue 8 Pages 2146-2151
    Published: 1980
    Released: April 19, 2006
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    The long-wavelength bands of the absorption spectra of 10-methylacridinium (MeAcr), Acridine Orange (AO), and Acridine Yellow (AY) in the poly(vinyl alcohol) film were investigated by the linear dichroism method. The parallel- and perpendicular-dichroic spectra of each dye were resolved into the long-axis and short-axis polarized absorption components. From these component bands the isotropic spectrum was reconstituted and the reduced dichroism spectrum was simulated by computer with a new technique which utilizes a general expression for the reduced dichroism of planar molecules with the multiple band structure. A weak absorption band (or bands) hidden in a strong one could be revealed by reproducing the observed isotropic and linear-dichroic spectra. The vibrational sub-bands of MeAcr were shown to have the average intervals of ca. 1.5×103 cm−1 for the short-axis polarized 1La band and of ca. 0.7×103 cm−1 for the long-axis polarized 1Lb band. In the visible region of the isotropic spectrum, the weak 1La band of AO was clearly shown to consist of the fine structure with a regular energy separation, although it is overlapped with the intense 1Lb band which is also composed of a vibrational structure. The same spectral feature was observed for AY. The dichroic results are discussed under considerations of (1) the overlap of the mutually orthogonal transition moments, whose angles were determined relative to the long axis of the C2v-symmetric dye molecule, (2) the angle between the orientation axis and the long axis of the molecular plane, and (3) the average degree of orientation of dye molecules in the film.
  • Kimihiko Hirao
    1980 Volume 53 Issue 8 Pages 2152-2158
    Published: 1980
    Released: April 19, 2006
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    The orbital ambiguity in the Hartree-Fock theory is removed in such a way as to improve the convergence property of the configuration interaction calculation. A practical proposal is made to obtain efficient orbitals for use in construction of wavefunctions. These orbitals are called the zeroth-order natural orbitals and their partner orbitals. It is also demonstrated by an illustrative calculation that use of partner orbitals rather than SCF orbitals gives much more rapid convergence and greater physical insight.
  • Masamichi Yamada, Haruo Kuroda
    1980 Volume 53 Issue 8 Pages 2159-2162
    Published: 1980
    Released: April 19, 2006
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    A sample-holding device to study the photoelectron take-off angle dependence of XPS spectrum is described. The take-off angle dependence was studied on a silicon surface covered with an oxide layer and a contamination carbon layer, and the (thickness)/(electron attenuation length) ratio of each layer was determined from the analysis of the angular dependence of the Si2p, O1s, and C1s peak intensities.
  • Toshihiro Amano, Yoshihiro Osamura, Eiko Kai, Kichisuke Nishimoto
    1980 Volume 53 Issue 8 Pages 2163-2166
    Published: 1980
    Released: April 19, 2006
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    The geometry of benzyl radical, nitrobenzene anion-, benzaldehyde anion-, aniline cation-, and phenol cationradicals is optimized by means of the energy gradient method in the framework of the CNDO/2 method, and used for the calculation of spin densities by the INDO-UHF method. The geometrical change from a neutral molecule to the ion radical can be understood by considering the shape of particular MO’s. It was found that the molecular structure of benzyl radical is not a regular hexagon, the contraction of C1–C7 bond being remarkable. The correct order of the spin densities on ortho(ρ2)- and para (ρ4)-positions is obtained by the full geometry optimization. The structure of the deformed ring of benzyl radical is discussed in terms of the orbital mixing rule.
  • Tadashi Kato, Nobuyuki Ito, Tsunetake Fujiyama
    1980 Volume 53 Issue 8 Pages 2167-2172
    Published: 1980
    Released: April 19, 2006
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    The concept of a “moving unit”—a group of molecules which move together for the time much longer than the velocity auto-correlation time, τ—was introduced in order to obtain information about cooperative translational motions of molecules in associated solution. The mutual diffusion coefficient was theoretically expressed in terms of the self diffusion coefficients and the number of moving units. The theoretical results were applied to the study of the mutual diffusion coefficients for methanol–carbon tetrachloride and ethanol–carbon tetrachloride solutions measured by Rayleigh scattering. It was shown that the mean number of alcohol molecules which constitute a moving unit is much smaller than the mean association number of alcohol, especially in the high concentration range of alcohol. This indicates that the hydrogen-bonded polymer of alcohol molecules cannot move without changing the polymer shape within the time τ.
  • Tadashi Kato, Toru Nakanishi, Tsunetake Fujiyama
    1980 Volume 53 Issue 8 Pages 2173-2180
    Published: 1980
    Released: April 19, 2006
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    Light scattering spectra were observed for carbon tetrachloride solutions of methanol, ethanol, and 1-propanol. The Rayleigh intensities were reduced to concentration fluctuations. The observed concentration dependence of the concentration fluctuation was analyzed by using two distinct models: an ideal associated complex (IAC) model and a polymer chain (PC) model. In the IAC model, a group of hydrogen-bonded alcohol molecules is treated as a complex whose size is independent of the association number, l. In the PC model, on the other hand, the group of hydrogen-bonded molecules is treated as a linear polymer whose length is proportional to l. It was shown that the PC model can explain both the concentration fluctuation and the heat of mixing data, while the IAC model cannot be applied to the present systems. The mean association number obtained by the IAC model was discussed on the basis of the relation between the concentration fluctuation and the spatial correlation of microscopic density.
  • Hiroshi Yesaka, Takayoshi Kobayashi, Kaoru Suzuki, Saburo Nagakura
    1980 Volume 53 Issue 8 Pages 2181-2184
    Published: 1980
    Released: April 19, 2006
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    The time dependence of fluorescence intensity after picosecond laser excitation and the steady-state fluorescence intensity were measured in order to study the mechanism of fluorescence quenching of anthracene by maleic anhydride in 1,4-dioxane. The nonlinear relationship between the reciprocal of steady-state fluorescence intensity and quencher concentration was observed for this system and interpreted in terms of the transient effect in the quenching process. The kinetic study by picosecond laser photolysis supports this interpretation. The reaction radius (R) and the sum of diffusion constants of both reactants (D) at various temperatures were determined by applying the diffusion model of Andre et al. The observed values are R=7.2 Å, D=1.46×10−5 cm2 s−1 (22 °C), 1.87×10−5 cm2 s−1 (50 °C), 2.42×10−5 cm2 s−1 (75°C). Studies of the main path in the quenching process by nanosecond laser photolysis suggest the existence of an extra path in the quenching process which overwhelms the fluorescent exciplex formation, the photoionization, the triplet anthracene formation, and the adduct formation.
  • Yoshiya Takenoshita, Robert C. Dunbar
    1980 Volume 53 Issue 8 Pages 2185-2187
    Published: 1980
    Released: April 19, 2006
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    Photodissociation spectra were observed for t-butylbenzene cation (m/e 134) and its daughter ion (m/e 119). Photoproduction spectra of the ions at m/e 119 and m/e 91 were observed in the visible region. It was shown that the photodissociation of m/e 134 yields m/e 119 almost 100% at wavelengths above 450 nm. Below 450 nm m/e 91 and m/e 57 appear as light-produced species. From pressure dependence and double resonance results, it was concluded that m/e 91 is a direct photoproduct from m/e 119, and that m/e 57 is produced in an ion-molecule reaction of m/e 91 with neutral t-butylbenzene. The photodissociation spectrum of m/e 119 is very similar to that of m/e 105 obtained by protonation of styrene, and it is reasonable to assume that m/e 119 has the protonated methylstyrene structure.
  • Hiromitsu Sagae, Masamichi Fujihira, Katsutaro Komazawa, Henning Lund, ...
    1980 Volume 53 Issue 8 Pages 2188-2194
    Published: 1980
    Released: April 19, 2006
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    The reaction of halogenonitrobenzenes (XNBs) with electrogenerated superoxide ion in N,N-dimethylformamide was studied electrochemically using cyclic voltammetry (CV) and controlled potential macro-electrolysis. It was shown in the CV that electro-generated superoxide ion reacts with all of the o- and p-isomers of iodo-, bromo-, and chloronitrobenzene in the dissolved oxygen medium. However the superoxide ion did not react with the other XNBs during CV. Controlled potential macro-electrolysis of oxygen in the presence of o- and p-bromonitrobenzene yielded the corresponding nitrophenols as the main products. The reaction mechanism via nucleophilic attack of the superoxide ion on the XNB, in the preference to an electron-transfer mechanism, is proposed.
  • Nagao Kobayashi, Masamichi Fujihira, Tetsuo Osa, Theodore Kuwana
    1980 Volume 53 Issue 8 Pages 2195-2200
    Published: 1980
    Released: April 19, 2006
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    The preparation and properties of a water soluble porphyrin having functional groups, α,β,γ,δ-tetrakis[1-(2-hydroxyethyl)pyridinium-4-yl]porphine, are described. This porphyrin is water soluble from below pH 0 to above pH 14. Acid-base titration revealed the diprotonated diacid-monocation equilibrium (pK4=1.0) and the monocation-free base equilibrium (pK3=1.9) in the acidic range and the free base-monoanion equilibrium (pK2=13.0±0.2) in the basic region. The zinc, iron, and cobalt derivatives of the porphyrin were also synthesized and purified. Catalytic properties of the iron and cobalt complexes for reduction of molecular oxygen in water are reported in terms of cyclic voltammetry. The electrochemical reduction utilizing these complexes was interpreted to proceed via electrochemical catalytic regeneration mechanism as had been observed for tetrakis(1-methylpyridinium-4-yl)orphinatoiron(III). The apparent rate constants for electron transfer from the iron and cobalt porphyrins to oxygen were estimated to be 3–4×107 and 1×107 dm3 mol−1 s−1, respectively.
  • Hisaharu Hayashi
    1980 Volume 53 Issue 8 Pages 2201-2204
    Published: 1980
    Released: April 19, 2006
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    Intermolecular biradical formation between the benzophenone triplet state with cis-3-methyl-2-pentene was studied by a ns laser-photolysis technique, the fourth harmonic (266 nm) of a Q-switched Nd : YAG laser being used as an exciting light source. We succeeded for the first time in observing the transient absorption due to the 1,4-biradical in the 380–300 nm region. Its lifetime was determined to be 25±4 μs (in acetonitrile), 15±4 μs (in methanol), and 6±2 μs (in cyclohexane). Quenching experiments with methyl viologen dication were also carried out in order to assign the observed transient absorptions.
  • Mitiko Miura, Yuji Shiro, Hiromu Murata
    1980 Volume 53 Issue 8 Pages 2205-2211
    Published: 1980
    Released: April 19, 2006
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    In treating the lattice dynamics strictly, it is important to separate the short-range forces into various kinds according to their characters: covalent-bond, characteristic repulsive, and van der Waals. The purpose of this paper is to describe a method of separation and an appropriate treatment which is applicable to any crystal with any properties. For the repulsive and the van der Waals interactions, we apply the Jones-type potential function, varying as an inverse power of the distance. The results indicate that the repulsive force serves to emphasize the ionicity in the crystal-force field and that the covalent-bond force cannot be represented reasonably by the use of the valence force to such a crystal as the wurtzite structure, forming a coordination lattice.
  • Koichiro Miyajima, Hiromitsu Yoshida, Yoshihiro Kuroda, Masayuki Nakag ...
    1980 Volume 53 Issue 8 Pages 2212-2216
    Published: 1980
    Released: April 19, 2006
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    The quadrupole relaxation of 14N nucleus of guanidinium bromide has been measured in aqueous ternary solutions containing symmetrical tetraalkylammonium salts by the 1H NMR method. By means of Pople’s line shape analysis and the Debye-Einstein equation, it has been confirmed that no complex formation takes place in the aqueous ternary solution containing symmetrical tetraalkylammonium salts. The rotational correlation time of the guanidinium ion is linearly related to the absolute viscosity of the solutions containing the homologous series of alkylammonium salts. A similar relationship was obtained for the ternary solutions with sugars or polyethylene glycols. This suggests that the correlation time depends on the microviscosity around the guanidinium ion.
  • Kinsi Motomura, Masaki Ikematsu, Yoshiteru Hayami, Hirosi Matuo, Ryohe ...
    1980 Volume 53 Issue 8 Pages 2217-2220
    Published: 1980
    Released: April 19, 2006
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    The surface pressure of mixed monolayers of octadecylammonium chloride and tetradecanoic acid has been measured as a function of mean area per film molecule at various compositions and temperatures. It has been observed that the transition pressure from expanded to condensed state of either constituent decreases with the addition of the other one. This behavior has been called a negative azeotropy in the two-dimensional state in contrast to the positive azeotropy observed for the ethyl heptadecanoate–tetradecanoic acid system. By applying the thermodynamic treatment, the phase diagram has been constructed and the apparent molar entropy and energy associated with the phase transition have been calculated. The results support the view that the negative azeotropic transformation in the mixed monolayer is brought about by the mutual interaction between octadecylammonium chloride and tetradecanoic acid molecules which is stronger than that between the same kind of molecules.
  • Takayoshi Kawai, Shin-ichi Ishiguro, Hitoshi Ohtaki
    1980 Volume 53 Issue 8 Pages 2221-2227
    Published: 1980
    Released: April 19, 2006
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    The hydrolytic reactions of lead(II) ions were studied at 25 °C by means of potentiometric titrations by using a glass electrode in water and dioxane–water mixture (dioxane contents: 0.1 and 0.2 mol fractions) containing 3 mol dm−3 LiClO4 as a constant ionic medium. Four complexes, Pb3(OH)33+, Pb4(OH)44+, Pb3(OH)42+, and Pb6(OH)84+ were found in the solvent systems examined at pH\lesssim8, and the formation constant *βpq for the reaction, qPb2++pH2O=Pbq(OH)p(2qp)++pH+, was determined. The autoprotolysis constants Ki in the same solvent systems were also obtained by use of a hydrogen electrode. The formation constant βpq(=*βpq/Kip) for the reaction, qPb2++pOH=Pbq(OH)p(2qp)+ was evaluated by combining the formation constants *βpq and the autoprotolysis constants obtained. The free energy change of transfer from water to a dioxane-water mixture for the reaction could be estimates as ΔGpqt=−RTln{βpq(mix)⁄βpq(aq)}. The values (1/p)ΔGpqt of hydroxo complexes of various metal ions such as lead(II), copper(II), nickel(II), beryllium(II), and cadmium(II) ions were approximately independent of the complexes at a given concentration of dioxane. This result suggested that the formal charge per metal ion of the complex, z′ (=zp/q; z: charge of a metal ion), rather than the total charge of the complex, zqp, is essential for the interactions between the hydroxo complexes and solvent molecules.
  • Sadaaki Murakami, Kotaro Ogura, Takashi Yoshino
    1980 Volume 53 Issue 8 Pages 2228-2235
    Published: 1980
    Released: April 19, 2006
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    The complex formation equilibria between several bivalent metal ions and 3,3′-bis[N,N′-bis(carboxymethyl)aminomethyl]-o-cresolsulfonphthalein (XO) have been investigated potentiometrically and spectrophotometrically. The metal ions studied here were Co(II), Ni(II), Cu(II), Zn(II), Pb(II), and Cd(II). The formation constants and visible-absorption-spectrum parameters of these metal complexes have been determined. It has been found that all these metal ions form 1:1 and 2:1 (metal: XO) complexes with XO. Moreover, the complex of each composition changes into one of several protonated ones depending on the pH of the solution. The probale structures of the complexes in solution are discussed.
  • Shin-ichi Nishikiori, Toschitake Iwamoto, Yukichi Yoshino
    1980 Volume 53 Issue 8 Pages 2236-2240
    Published: 1980
    Released: April 19, 2006
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    Novel clathrate compounds, Hofmann-pn type Cd(pn)Ni(CN)4·3/2G (G=C4H5N, C4H4S, or C6H6) and pn-Td type Cd(pn)Cd(or Hg)(CN)4·3/2C6H6, have been prepared. Their host structures are analogous to those of the known Hofmann-en type Cd(en)Ni(CN)4·2G and en-Td type Cd(en)Cd(or Hg)(CN)4·2C6H6. The propylenediamine (pn: 1,2-diaminopropane) molecule ambidently bridges six-coordinate Cd atoms, as the en (ethylenediamine) does in the latter types of clathrates. The guest molecules occupy at random three quarters of the cavities in the host structures: every remaining cavity contains two methyl groups of the pn molecules. The crystal structure of Cd(l-pn)Ni(CN)4·3/2C4H5N has been analyzed in order to demonstrate the structural features. The crystal is tetragonal with the space group P422, a=7.575(2) and c=7.742(2) Å, and Z=1. The degree of disorder is extremely high with regard to the arrangement and orientation of the l-pn molecule.
  • Taitiro Fujinaga, Satoshi Okazaki, Tsutomu Nagaoka
    1980 Volume 53 Issue 8 Pages 2241-2247
    Published: 1980
    Released: April 19, 2006
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    Ion association of 1,2-naphthosemiquinone with the alkali metal cations in acetonitrile has been comprehensively studied by the use of ESR, absorption spectroscopy, polarography and with MO calculation. A continuous flow electrolysis system with a glassy carbon column electrode has been developed for the rapid quantitative preparation of organic free radicals, whose ESR spectrum or absorption spectrum was observed in situ. The formation constants of the ion pair with K+, Na+, and Li+ were estimated as 103.2, 104.5, and 108.0, respectively. By the addition of alkali metal cations, the half-wave potentials shifted to more positive potential in the order of K+<Na+<Li+. The proton hyperfine splitting constants in the ESR also varied in this order. This column electrolysis method is considered to be a powerful technique, particularly for the study of short lived free radicals, because the quantitative electrolysis is performed rapidly even in a solution of extremely diluted supporting electrolyte, such as 0.1 mM (mmol/dm3).
  • Hisashi Okawa, Yoshihiko Numata, Ayako Mio, Sigeo Kida
    1980 Volume 53 Issue 8 Pages 2248-2251
    Published: 1980
    Released: April 19, 2006
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    Cobalt(III) complexes, [Co(l-mop=aa)2] and [Co(cop=aa)2] (aa=ala, val, leu, phe), where H2(l-mop=aa) and H2(cop=aa) denote amino acid-Schiff bases of l-menthyl 3-(o-hydroxybenzoyl)propionate and cholesteryl 3-(o-hydroxybenzoyl)propionate, respectively, were prepared in solution. The intensity of the CD peak induced at 520 nm changes with the solvent used for preparation of the complex, decreasing in the order: ethanol, methanol, dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile. Since the order corresponds to the increasing order of the CH···π-interaction between the solvent and benzene, it seems that the CH···π-interaction between the chiral group and the aromatic nucleus in the ligand plays an important role in determining the configuration of the complexes.
  • Shoji Nakada, Mutsuo Yamada, Tasuku Ito, Masatoshi Fujimoto
    1980 Volume 53 Issue 8 Pages 2252-2256
    Published: 1980
    Released: April 19, 2006
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    Reversible thermochromisms of copper(II) complexes with 3,3′-bis[bis(carboxymethyl)aminomethyl]thymol-sulfonphthalein (Methylthymol Blue; MTB) and 3,3′-bis[bis(carboxymethyl)aminomethyl]-p-xylenolsulfonphthalein (Methylxylenol Blue; MXB) were studied in aqueous solutions. The thermochromisms of these complexes were primarily ascribed to the temperature-dependence of the protolytic equilibria between a complex species AH having an uncoordinated free phenolic hydroxyl group and a complex species A having a coordinated phenolate group: AH\ ightleftarrowsA+H. The equilibrium constants K of the reactions at 25 °C were determined to be p(K/mol dm−3)=4.66 for Cu(II)–MTB and 4.78 for Cu(II)–MXB. The thermodynamic parameters ΔH and ΔS for the reactions were calculated to be 26±2 kJ mol−1 and −6±3 J K−1 mol−1 (298 K) for both complexes, respectively. The rate constants of the proton dissociation of the phenolic hydroxyl group in the complexes AH were estimated to be 1.6×105 and 1.8×105 s−1 for Cu(II)–MTB and Cu(II)–MXB, respectively. The thermodynamic and kinetic data are discussed in terms of the effects of the substituents in the ligand molecules on the thermochromism.
  • Minahiro Okabayashi, Ken-ichi Okamoto, Jinsai Hidaka
    1980 Volume 53 Issue 8 Pages 2257-2261
    Published: 1980
    Released: April 19, 2006
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    ((2S,S′-1,1′-Trimethylenedipyrrolidine-2,2′-dicarboxylato)(α-amino carboxylato)cobalt(III) complexes were prepared and characterized, where the α-amino carboxylate ligand is glycinate, (R)- or (S)-alaninate, (R)- or (S)-valinate, sarcosinate, N-ethylglycinate, (R)-prolinate, or (S)-pipecolate ((S)-2-piperidinecarboxylate). Of the three possible isomers, only the Λ-uns-mer form was prepared for each of the complexes except for the glycinato complex. The (R)-prolinato and (S)-pipecolato complexes were stereoselectively prepared by using (RS)-proline or (RS)-pipecolic acid. The pipecolate ion coordinated selectively was assigned to S(C) configuration on the basis of the CD measurement of the 2,4-dinitrophenyl-pipecolic acid. The nitrogen atom of the sarcosinate, N-ethylglycinate, (R)-prolinate, or (S)-pipecolate ion, which coordinated stereoselectively to Co(III) ion, took the R(N) configuration. The stereoselectivity in this work was discussed on the basis of the electronic absorption, CD, and PMR spectra.
  • Kazunori Sakata, Mamoru Hashimoto, Noriyoshi Tagami, Yukito Murakami
    1980 Volume 53 Issue 8 Pages 2262-2270
    Published: 1980
    Released: April 19, 2006
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    The oxovanadium(IV), nickel(II), copper(II), and palladium(II) complexes of 5,14-dihydrodibenzo[b,i][1,4,8,1l]tetraazacyclotetradecine and 7,8,15,16,17,18-hexahydrodibenzo[b,j][1,4,8,1l]tetraazacyclotetradecine have been synthesized, and studied by electronic, vibrational, NMR, ESR, and ESCA spectroscopy. The absorption bands appearing in the energy region greater than 16800 cm−1 were attributed to π→π* transitions within a ligand molecule and metal to ligand charge-transfer transitions. The ligand-field bands were not assigned for the present complexes, because all the ligand-field bands were obscured by the π→π* and charge-transfer bands of high intensity. The metal complexes assume the square-planar configurations since no significant absorption band was detected in the region below 17000 cm−1. A strong band appearing at ca. 1620 cm−1 was assigned to the C=N stretching mode, and this band was shifted to lower frequency upon metal coordination. A V=O streching band was observed at ca. 950 cm−1 for the oxovanadium complexes. The oxovanadium, nickel, copper, and palladium complexes showed a single nitrogen Is peak by ESCA spectroscopy, whereas the metal-free ligand, 5,14-dihydrodibenzo[b,i][1,4,8,1l]tetraazacyclotetradecine, revealed double nitrogen Is peaks. ESR spectra were measured in xylene–benzene (2: 1 v/v) as well as in the corresponding ligand matrices at room temperature. Judging from g tensors, the copper complexes were confirmed to have D2h coordination symmetry with an unpaired electron in the dxy orbital. On the other hand, vanadium(IV) is in C4v coordination symmetry with an unpaired electron in the dx2−y2.
  • Hiromitsu Araki, Young Hong Ryoo, Motonori Eguchi, Ryoko Matsuzaki, Yu ...
    1980 Volume 53 Issue 8 Pages 2271-2274
    Published: 1980
    Released: April 19, 2006
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    The reaction products obtained by heating a mixture of α-Fe2O3 and carbon in a SO2 stream at various temperatures were examined. The possible reactions during the above process were also examined. The solid products obtained by heating a mixture of α-Fe2O3 and carbon in a SO2 stream were Fe3O4 at 500–700 °C, pyrrhotite and Fe3O4 at 750 °C , and pyrrhotite (Fe0.88S) alone at 800 °C. Sulfur was obtained outside the heating zone throughout the temperature range. The process of the formation of pyrrhotite by the reaction between α-Fe2O3 and SO2 in the presence of carbon can be represented as follows: The reaction between carbon and SO2 occurs even at 350 °C to form sulfur, and the reaction proceeds markedly above ca. 700 °C. Above ca. 500 °C, the reductions of α-Fe2O3 with carbon and sulfur occur to form Fe3O4. Above ca. 750 °C, pyrrhotite is formed by the reaction between Fe3O4 and sulfur. These results were supported by the thermodynamical consideration based on the chemical potential diagram for the Fe–S–C–O system.
  • Kazuo Kashiwabara, Kazuhiro Hanaki, Junnosuke Fujita
    1980 Volume 53 Issue 8 Pages 2275-2280
    Published: 1980
    Released: April 19, 2006
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    Four chiral diphosphines, (R,R)-1,2-bis[N-methyl(diphenylphosphino)arnino]cyclohexane, (R,R)-1,2-bis[(diphenylphosphino) amino] cyclohexane, (R)-1,2-bis[N-methyl(diphenylphosphino)amino]propane, and (R)-1,2-bis[(diphenylphosphino)amino] propane have been prepared from the corresponding optically active diamines. The cationic 1,5-cyclooctadiene rhodium(I) complexes with these diphosphines act as effective homogeneous catalysts for the stereoselective hydrogenation of α-acylaminoacrylic acids. The optical yields and the absolute configurations of the products depend on the kind of diphosphine ligands. The (R,R)-1,2-bis[N-methyl(diphenylphosphino)amino]cyclohexane complex catalyst yields N-benzoyl-(S)-leucine, N-benzoyl-(S)-phenylalanine, and N-acetyl-(S)-phenylalanine in 94, 92, and 89% e.e., respectively. The other three catalysts are less effective (6–74% e.e.). The aminophosphine complexes with methyl groups on the nitrogen atoms always give (S)-amino acids, those with no methyl group (R)-amino acids. Such a difference in the chiral recognition has been discussed on the basis of circular dichroism spectra and Dreiding molecular models of the rhodium(I) complexes.
  • Juzo Nakayama, Toshiro Takemasa, Masamatsu Hoshino
    1980 Volume 53 Issue 8 Pages 2281-2284
    Published: 1980
    Released: April 19, 2006
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    2-(p-Bromophenacylthio)-1,3-dithiolylium bromide, when treated with triethylamine, gave 2-(p-bromophenacylidene)-1,3-dithiole (17%) and bis[(p-bromobenzoyl)(1,3-dithiol-2-ylidene)methyl] disulfide (72%). Treatment of 2-phenacylthio-1,3-dithiolylium bromide with triethylamine also gave similar results. On the other hand, 2-(p-bromophenacylthio)-1,3-dithiolanylium bromide yielded 1-(p-bromophenyl)-2-(1,3-dithiolan-2-yl)-2-thioxoethanone (12%) in addition to 2-(p-bromophenacylidene)-1,3-dithiolane (49%) contrary to the reported results. These results can best be rationalized by 1,3-cyclization of thiocarbonyl ylide intermediates to the valence tautomeric episulfides.
  • Hiroshi Suginome, Tsutomu Uchida, Kazuhiko Kizuka, Tadashi Masamune
    1980 Volume 53 Issue 8 Pages 2285-2291
    Published: 1980
    Released: April 19, 2006
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    D-Nor-5α-androstan-16-one was prepared via seven steps from 16-diazo-3β-hydroxyandrost-5-en-17-one. The major products of the photolysis of its acetylhydrazone in dioxane containing oxygen were the parent ketone and 17-oxa-5α-androstan-16-one, accompanied by low yields of three isomeric lactams: 17-aza-5α-androstan-16-one, 16-aza-5α-androstan-17-one, and 17-aza-5α,13α-androstan-16-one. These three are the same lactams formed in the photo-Beckmann rearrangement of the corresponding oxime, D-nor-5α-androstan-16-one oxime. Their formation from the acetylhydrazone may have some mechanistic significance with regard to the path of the formation of lactams in the photolysis of 5α-androstan-17-one acetylhydrazone in the presence of oxygen reported previously. The mass spectrometric fragmentations of fifteen D-nor-5α-androstanes with functional groups at their C-16 positions are described.
  • Hiroshi Suginome, Tsutomu Uchida
    1980 Volume 53 Issue 8 Pages 2292-2296
    Published: 1980
    Released: April 19, 2006
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    Irradiation of D-nor-5α-androstan-16-one oxime in methanol leads to a mixture of seco-nitriles; D-nor-13,16-seco-5α-androst-13(18)-ene-16-nitrile (3), D-nor-13,16-seco-5α-androst-12-ene-16-nitrile (7), 13ξ-methoxy-D-nor-13,16-seco-5α-androstane-16-nitrile (8), and 15-hydroxy-D)-nor-15,16-seco-5α-androstane-16-nitrile (9). These result from ionic α-fissions at either of the α-bonds. Low yields of three lactams, 17-aza-5α-androstan-16-one (6), 17-aza-5α,13α-androstan-16-one (11), and 16-aza-5α-androstan-17-one (5), resulting from photo-Beckmann rearrangement, are also formed. The formation of 11 is the second proven example of a photo-Beckmann rearrangement in which a chirality of the migrating carbon center is not retained in the product lactam and an intervention of a ring-opened intermediate must be involved. It was found that direction of the α-cleavage of this excited four-membered cyclic ketone oxime was not governed only by the stability of cleaved ions, since seco-nitrile 9 resulting from α-fission to a less stable primary carbonium ion was formed together with seco-nitriles 3, 7, and 8 from a more stable tertiary carbonium ion. The Beckmann rearrangement of the mixture of syn and anti oximes with thionyl chloride afforded the two expected lactams 5 and 6 together with the products of Beckmann fission 3 and D-nor-13,16-seco-5α-androst-13(14)-ene-16-nitrile resulting from a cleavage to tertiary carbonium ion.
  • Takashi Tatsumi, Kazuhiko Sekizawa, Hiroo Tominaga
    1980 Volume 53 Issue 8 Pages 2297-2303
    Published: 1980
    Released: April 19, 2006
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    Reactions of some dpe(dpe=Ph2PCH2CH2PPh2) complexes of molybdenum with nitrosyl hexafluorophosphate (NOPF6) have been investigated. The reaction of MoH4(dpe)2 with NOPF6 in benzene-methanol affords two types of complexes, a protonated species, trans-[MoF(HNO)(dpe)2]PF6 (1a) and a non-protonated species, trans-MoF(NO)(dpe)2·1/2C6H6. From the nitroxyl complex 1a, a series of nitrosyl complexes has been obtained. Some nitrosyl complexes exhibit cis-trans isomerism. Reactions of the nitrosyl complexes with protonic acids afford the corresponding nitroxyl complexes or the anion substitution products. Cationic nitrosyl complexes are obtained by the reactions of Mo(CO)L(dpe)2 (L=N2 or C2H4) and Mo(C2H4)2(dpe)2 with NOPF6. Attempts were also made to prepare nitrosyl complexes of molybdenum by use of other nitrosylating agents.
  • Masaru Tada, Hideki Hirano, Atsushi Suzuki
    1980 Volume 53 Issue 8 Pages 2304-2308
    Published: 1980
    Released: April 19, 2006
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    The syn-anti isomerization of acetylbenzocrown ether oximes was stimulated by the complex-formation with sodium ion. The photolysis of these oximes gave mother ketones and amides through an oxaziridine intermediate. The photolysis of the oximes was depressed by the formation of host-guest complexes. Reactivity in the photolysis of the crown ether oximes corresponds to that of 3,4-dimethoxyacetophenone oxime, whereas the reactivity of the complexed crown ether oxime with sodium ion corresponds to that of p-cyanoacetophenone oxime. Such behavior is explained by the change of the electronic properties of excited states of acetophenone oxime chromophore, which enhances the intersystem crossing.
  • Yuzuru Uchida, Yukinobu Hashimoto, Seizi Kozuka
    1980 Volume 53 Issue 8 Pages 2309-2314
    Published: 1980
    Released: April 19, 2006
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    Several N,O-diacyl-N-t-butylhydroxylamines and O-acyl-N-t-butylhydroxylamines were prepared, and their thermal decompositions were studied. The thermal decompositions of N,O-diacyl-N-t-butylhydroxylamines in tetralin gave substituted N-t-butylbenzamides, carboxylic acids, 1,1′-bitetralyl, and 1,2-dihydronaphthalene as the major products, together with small amounts of carbon dioxide, t-butylamine, and benzanilides. In the thermal decompositions of O-acyl-N-t-butylhydroxylamines, the products were t-butylamine, carboxylic acids, substituted N-t-butylbenzamides, 1,1′-bitetralyl, and 1,2-dihydronaphthalene.
  • Chung-gi Shin, Yasuchika Yonezawa, Katsumi Ajisaka, Juji Yoshimura
    1980 Volume 53 Issue 8 Pages 2315-2317
    Published: 1980
    Released: April 19, 2006
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    The configuration of the ethyl 2-bromo-3-nitro-2-alkenoate formed by the elimination of hydrogen bromide from ethyl 2,3-dibromo-3-nitroalkanoate was determined to be (Z) by the examination of the 13C NMR spectra.
  • Syun-ichi Kiyooka, Tsukasa Kodani, Kojiro Suzuki
    1980 Volume 53 Issue 8 Pages 2318-2321
    Published: 1980
    Released: April 19, 2006
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    The conformations of sodium enolate anions, derived from diethyl malonate and diethyl alkylmalonates (alkyl=methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and s-butyl), have been determined to be Z,Z-type by the analysis of their 1H-NMR spectra in DMSO. In the case of diethyl t-butylmalonate, such a Z,Z type contributes to the lesser extent to the conformations of the sodium enolate anion because of repulsion between the t-butyl substituent and the two ethoxyl groups, which exist in three types (Z,Z, Z,E, E,E) of conformation, as is evident in the 1H-NMR spectra. The IR spectra of sodium diethyl malonate in DMSO showed two characteristic absorption bands at 1679 and 1556 cm−1. The IR isotope shifts upon the use of the enolates of diethyl malonate-2-13C and diethyl malonate-1,3-13C2 suggested that these two bands are attributable to the C··O and C··C··C bonds. All sodium diethyl alkylmalonates except for the t-butyl derivative have two characteristic IR bands in the region of 1500–1700 cm−1, the bands on the high-frequency side of which have nearly equal wave numbers, while those on the low-frequency side have a good correlation with the substituent constant, σ*.
  • Tohru Sakakibara, Akinori Seta, Yoshifusa Tachimori, Rokuro Sudoh
    1980 Volume 53 Issue 8 Pages 2322-2326
    Published: 1980
    Released: April 19, 2006
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    Reaction of the title compound with acetylacetone in the presence of a catalytic amount of sodium hydroxide afforded the 2-C-diacetylmethyl and 2-C-acetylmethyl derivatives having the altro, gluco, and manno configurations. The 2-C-diacetylmethyl derivative with the altro configuration exceptionally exists in a skew boat form. The product ratio depends on solvent and the amount of THF.
  • Nobuyuki Hamanaka, Hisao Nakai, Masayasu Kurono
    1980 Volume 53 Issue 8 Pages 2327-2329
    Published: 1980
    Released: April 19, 2006
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    A report is given on the synthesis of a spiro prostaglandin analog via triketone obtained by the double Michael addition of 1,3-cyclopentanedione to 1,4-pentadien-3-one.
  • Makoto Komiyama, Shohei Inoue
    1980 Volume 53 Issue 8 Pages 2330-2333
    Published: 1980
    Released: April 19, 2006
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    Cleavages of p- and m-nitrophenyl 1-adamantanecarboxylates (1 and 2) were carried out in the presence of α-, β-, and γ-cyclodextrins at 16 °C. The complex formation of 1 with α-, β-, and γ-cyclodextrins decelerated its cleavage by 3.2, 28, and 13 fold, respectively, in the 99 : 1 (v/v) mixture of 0.1 mol dm−3 NaOH aqueous solution and acetonitrile. All α-, β-, and γ-cyclodextrins showed decelerations of the cleavages of 1 and 2 also in the 66 : 34 mixture of 0.1 mol dm−3 NaOH aqueous solution and acetonitrile, although the magnitudes of the rate effects were smaller. The decelerations of the cleavages of 1 and 2 by cyclodextrins were markedly in contrast with the accelerations of the cleavages of other phenyl esters by cyclodextrins previously reported, and were ascribed to the formation of the complexes, in which 1 and 2 were protected sterically and/or electrostatically by cyclodextrins.
  • Masaru Sato, Keiko Inaba, Seiji Ebine, Josuke Tsunetsugu
    1980 Volume 53 Issue 8 Pages 2334-2339
    Published: 1980
    Released: April 19, 2006
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    1,2-Dimethoxybiphenylene reacted with dichlorocarbene to give three chloro(methoxy)-6H-benzo[3,4]cyclobuta[1,2]cyclohepten-6-one derivatives, two chloro(methoxy)fluorenones and two dimethoxyfluorenones. The reaction with dibromocarbene gave similar products. The formation of these products serves as unequivocal chemical evidence for bond fixation of 1,2-dimethoxybiphenylene. The chloro(methoxy)-6H-benzo[3,4]cyclobuta-[1,2]cyclohepten-6-one was led to 9-chloro-5-hydroxy-6H-benzo[3,4]cyclobuta[1,2]cyclohepten-6-one, the first tropolone analogue of biphenylene. This compound was shown to exist in only one of the two possible tautomers in contrast with general monocyclic tropolones.
  • Yumihiko Yano, Yoshiharu Tamura, Yutaka Hoshino, Waichiro Tagaki
    1980 Volume 53 Issue 8 Pages 2340-2343
    Published: 1980
    Released: April 19, 2006
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    The oxidation of 2-(α-hydroxybenzyl)- and 2-(1-hydroxyethyl)thiazolium ions with 3-methyllumiflavin was studied kinetically in an aqueous buffer solution. The results indicate that the rate-determining step is carbanion formation followed by rapid oxidation. The carbanion formation was subjected to general base catalysis.
  • Takashi Sugimoto, Sadao Matsuura, Toshiharu Nagatsu
    1980 Volume 53 Issue 8 Pages 2344-2347
    Published: 1980
    Released: April 19, 2006
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    The synthesis of biopterin, D(and L)-erythro-neopterins, and their derivatives having a substituent at the 2-amino group via the 2-methylthio analogues is described. The 2-(methylthio)pteridines were synthesized by condensation of 4,5-diamino-6-hydroxy-2-(methylthio)pyrimidine with 5-deoxy-L-arabinose and D(and L)-arabinose phenylhydrazones, followed by oxidation with K3[Fe(CN)6] and O2 in the presence of KI in an acidic solution, respectively. Aminolysis of these thioethers with ammonia and other amines in the presence of acetic acid gave the title compounds.
  • Takashi Ando, Junko Yamawaki, Yoshimasa Saito, Yoshio Takai, Hiroshi Y ...
    1980 Volume 53 Issue 8 Pages 2348-2356
    Published: 1980
    Released: April 19, 2006
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    Trifluoroacetolysis rates and products were determined for eleven 4-(m- and p-substituted phenyl) butyl 6-methyl-2-naphthalenesulfonates. Most substrates solvolyze predominantly or even exclusively with aryl assisted (kΔ) pathway. Dissection of kΔ into Ar1-5 and Ar2-6 components was performed by means of quantitative 13C NMR study of suitably labeled p-methyl and p-fluoro derivatives; the results were 32.4% Ar1-5 and 67.6% Ar2-6 for the former and 43.3% Ar1-5 and 56.7% Ar2-6 for the latter. For other substrates the dissection was carried out by postulating two independent linear free energy relationships (LFER) for the two pathways determined by the above four partial rates. Ar2-6 is much prefered over Ar1-5 through the series; for the unsubstituted derivative 90.6% Ar2-6 vs. 9.4% Ar1-5 was determined. A completely different approach by means of non-linear regression analysis of kΔ as a sum of two independent LFER gave fairly different and rather unsettled results, limitations of such an approach being suggested. The characteristics of remote aryl participation are discussed based on the above data.
  • Akira Itoh, Shuji Ozawa, Koichiro Oshima, Shizuka Sasaki, Hajime Yamam ...
    1980 Volume 53 Issue 8 Pages 2357-2362
    Published: 1980
    Released: April 19, 2006
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    The reaction of cis- or trans-5-isopropenyl-2-methyl-2-cyclohexenyl diethyl phosphate (1) with Me2AlX (X=OPh, SPh, NHPh) in hexane results in substitution of the –O–PO(OEt)2 group with X under predominant inversion. In contrast, treatment of cis- or trans-1 with trialkylaluminum produces predominantly the allyl-nonallyl couplingproducts of the same (thermodynamically more stable) configuration. Similar alkylation of endo- and exo-2-acetoxynorcarane gave endo-2-methylnorcarane, exclusively.
  • Sivasankaran nair Janardhanan, Chatty Kalidas
    1980 Volume 53 Issue 8 Pages 2363-2365
    Published: 1980
    Released: April 19, 2006
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    The selective solvation of Ag(I) bromate and iodate was studied in dimethyl sulfoxide–water mixtures at 30 °C by solubility and EMF measurements. The solubility of silver bromate decreases down to XDMSO=0.2 and thereafter increases with addition of dimethyl sulfoxide, the solubility of silver iodate continuously decreasing under the same conditions. The transfer free energy of silver cation decreases while that of halate ions increases with the addition of dimethyl sulfoxide. The solvent transport number, Δ, passes through a maximum around XDMSO=0.5 in both cases. These results were interpreted in terms of a heteroselective solvation of both the salts, the silver ion being preferentially solvated by dimethyl sulfoxide and the halate ions selectively hydrated by water in the mixtures.
  • Ganesh Prasad Panigrahi, Radhasyam Panda
    1980 Volume 53 Issue 8 Pages 2366-2370
    Published: 1980
    Released: April 19, 2006
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    The kinetics of oxidation of dialkyl sulfides by peroxomonophosphate in aqueous medium at 308 K and μ=0.4 mol dm−3 follow the rate expressions (i) −d[peroxomonophosphate]/dt={k1[H2PO5]+k2[HPO52−]}[sulfide] in the pH region 6.8–8.7 where k1 and k2 values are 336.5 and 0.95, 69.7 and 0.254, and 27.5 and 0.126 dm3 mol−1 s−1 for dimethyl, diethyl and dipropyl sulfides, respectively, (ii) −d[peroxomonophosphate]/dt=k2[HPO52−]·[sulfide] in the pH region 8.5–12.5, where the average k2 values are 0.86, 0.247, and 0.128 dm3 mol−1 s−1 for dimethyl, diethyl, and dipropyl sulfides, respectively, and (iii) −d[peroxomonophosphate]/dt={k2[HPO52−]+k3·[PO53−]}[sulfide] in the pH region 12.5–13.7, the k2 and k3 values being 0.947 and 0.107, and 0.233 and 0.018 dm3 mol−1 s−1 for dimethyl, and diethyl sulfides, respectively. The mechanism of the reaction is in line with a nucleophilic attack of the sulfide-sulfur on the peroxo oxygen, giving rise to SN 2-type transition states which undergo oxygen-oxygen bond fission to give the corresponding sulfoxide and phosphate.
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