Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 67 , Issue 12
Showing 1-40 articles out of 40 articles from the selected issue
  • Tsugitoshi Ogura, Masazumi Tanoura, Kiyoshi Tatsuhara, Akio Hiraki
    1994 Volume 67 Issue 12 Pages 3143-3149
    Published: 1994
    Released: August 01, 2006
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    The behaviors and roles of anionic surfactants in highly loaded aqueous suspensions of carbon black were investigated in order to clarify how they increase the achievable concentration while maintaining the apparent viscosity of a suspension. In a suspension, organic particles and the water bound to them define the effective volume of the solid particles, which determines the relative viscosity, as formulated by the Brinkman equation. The surfactant was found to be adsorbed on the organic particles, decreasing the amount of bound water, as measured by 1H NMR. The result of the study was that a surfactant in a highly-loaded aqueous suspension plays the following three roles at the same time: (Role-1) The decrease in the bound water due to the surfactant allows an increase in the achievable solid concentration at a fixed viscosity by decreasing the effective volume fraction of solids in a suspension. (Role-2) The adsorption of the surfactant was also found to be necessary to inhibit the aggregation of dispersed particles; if, however, the amount of surfactant is insufficient, aggregation can occur even with mechanical stirring, owing to a hydrophobic interaction among the particles. (Role-3) The surfactant influences the viscosity of the suspension through the “k” factor of the Brinkman equation. Surfactants with larger molecules were found to give a larger k value, thus increasing the viscosity, probably because of their effects on the interactions between the dispersed particles.
  • Anil Kumar
    1994 Volume 67 Issue 12 Pages 3150-3152
    Published: 1994
    Released: August 01, 2006
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    The Born model is frequently used for calculating the work of solvation or free energy of ion–solvent interactions. The original Born equation does not reproduce the experimental data on solvation free energy, possibly due to the fact that the model does not take in account the changes in the structure of solvent in presence of an ion. The model also fails to account certain other experimental observations. A new derivation of the model is presented assuming the changes in the structure of solvent being analogous to surface phenomena. In addition to the successful checking its validity against experimental data, the revised expression can also yield the generalized Dupre rule for surface effects. Significance of new terms and their impact in accounting observed trends are discussed.
  • Yoshimi Sueishi, Tatsuhiko Mukai, Kazumi Matsumoto, Shunzo Yamamoto, N ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3153-3158
    Published: 1994
    Released: August 01, 2006
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    The thermal isomerizations of mercury and silver dithizonates (Hg(HDz)2 and Ag(HDz)) were followed spectrophotometrically at high pressures and in various solvents. From the pressure dependence of the rate, the activation volumes for the isomerization of Hg(HDz)2 in aprotic solvents were estimated to be about 6 cm3 mol−1, and were compared with those for Ag(HDz). The observed positive values of the activation volumes have been explained in terms of the increase in the intrinsic volume accompanying the isomerization of dithizone. Based on these results, a possible structure of the transition state for the thermal isomerization of Hg(HDz)2 in aprotic solvents was proposed. Moreover, we have followed the thermal isomerization of Hg(HDz)2 in various types of alcohols at low temperatures. The results in alcohols are discussed in terms of solvent hydrogen-bonding ability, and a reaction mechanism is proposed.
  • Yasuo Kameda, Hidekazu Ebata, Takeshi Usuki, Osamu Uemura, Masakatsu M ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3159-3164
    Published: 1994
    Released: August 01, 2006
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    A radial distribution study for aqueous 5 mol% glycine solutions was carried out involving time-of-flight neutron diffraction measurements. An isotopic substitution technique was applied to both nitrogen and hydrogen atoms of the sample in order to determine the hydration structure around the amino group of the glycine molecules in an aqueous solution. It has been clarified that there exist 3.0 ± 0.6 water molecules coordinated to the amino group of a glycine molecule with intermolecular distances of rN···O = 2.85 ± 0.05 Å and rN···D = 3.25 ± 0.05 Å. These values suggest that a hydrogen bond is formed between the amino group of a glycine molecule and the nearest-neighbor water molecules in the aqueous glycine solution.
  • Tomoo Sato, Naohide Maeda, Hideo Ohkoshi, Yoshiro Yonezawa
    1994 Volume 67 Issue 12 Pages 3165-3171
    Published: 1994
    Released: August 01, 2006
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    An aqueous silver perchlorate–sodium dodecylsulfate (SDS)–benzophenone (BP) solution was photolyzed with either UV or near-UV light. Irradiation with 253.7 nm light, which was absorbed by both BP and silver ions, brought about the formation of collidal silver and the photobleach of BP. Peptization of colloidal silver agglomerates after prolonged irradiation was ascribed to electron injection from the benzophenone ketyl radical (BPK). The formation of colloidal silver and the photobleach of BP were also caused by irradiation with 365 nm light, which was absorbed solely by BP (sensitized reaction). A simple reaction scheme was introduced and the initial rates for the sensitized photoreduction of silver ions and the photobleach of BP were expressed in closed forms. Suitable combinations of the kinetics parameters and the extinction coefficient of colloidal silver were proposed in order to interpret the dependences of the initial rates on the reactant concentrations.
  • Takao Kobayashi, Hidenori Matsuzawa, Suehiro Iwata
    1994 Volume 67 Issue 12 Pages 3172-3178
    Published: 1994
    Released: August 01, 2006
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    The electron correlation effects for the geometry and stability of the ammonia–halogen (NH3–Cl2 and NH3–ClF) and the methylamine–halogen (CH3NH2–Cl2 and CH3NH2–ClF) are examined with ab initio molecular orbital calculations. The intermolecular distance, r(N–Cl), with the second order Møller–Presset (MP2) method are substantially shorten from the corresponding values with the self-consistent field (SCF) method. The halogen–halogen distance is slightly lengthened with the MP2 method from those determined with the SCF calculations. With the MP2 method the stabilization energies (ΔE) become large from those of the SCF calculation. Large high-frequency shifts for two intra CH3–NH2 coupled motions are found. The frequency shift and intensity change in the complex formation are mode-specific. The potential energy surfaces of the ground and low-lying excited states of NH3–ClF complex are calculated with the configuration interaction method. The first excited state is directly dissociated to NH3Cl + F. The charge-transfer excited state lies higher than the π* → σ* transition of ClF molecule, and is dissociated into NH3 + Cl + F. The NH3Cl (C3v symmetry), generated from the lowest excited states, is a stable radical. The reaction NH3Cl → NH2 + HCl is also endothermic, though the high barrier prevents the hydrogen shift to chlorine.
  • Haruhiko Yokoyama, Hiroyuki Kon, Toshiaki Hiramoto, Kazuteru Shinozaki
    1994 Volume 67 Issue 12 Pages 3179-3186
    Published: 1994
    Released: August 01, 2006
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    Conductivity measurements for aqueous solutions of sulfates of hexaamminecobalt(III) ([Co(NH3)6]3+) and tris(ethylenediamine)cobalt(III) ([Co(en)3]3+) complexes have been made at various temperatures from 0 to 50 °C. The conductivity data were analyzed to obtain the first ion-association constants, but could not be completely explained if the second ion association (triple-ion formation between ion pair and sulfate ion) was not taken into consideration. The ion-association constants had minimum values at particular temperatures and were significantly larger than those predicted by electrostatic ion-association theories. Excess thermodynamic functions for the first ion association over the theoretical prediction were estimated and explained by assuming the ion–ion and ion–water hydrogen bonding. The excess entropy and enthalpy changes were significantly increased with increasing temperature, while the Gibbs free energy change was little dependent on temperature; these results were attributed to the destruction of bulk water structure with temperature. A similar contribution of hydrogen bonding was present in the second ion association besides the electrostatic interaction between the anion and the ion pair having a large dipole moment. The difference between [Co(NH3)6]3+ and [Co(en)3]3+ in hydrogen bonding is also discussed.
  • Takehiko Mori, Yohji Misaki, Tokio Yamabe
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3187-3190
    Published: 1994
    Released: August 01, 2006
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    The title organic charge transfer salt, where EP-TTP is 2-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)-5(4,5-trimethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, has so-called β-type donor arrangement, but the Fermi surface is basically one-dimensional. This salt exhibits metallic conductivity down to 0.7 K. The thermoelectric power and ESR show simple metal-like behavior.
  • Yasuo Izumi, Masaki Hoshikawa, Ken-ichi Aika
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3191-3200
    Published: 1994
    Released: August 01, 2006
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    The effects of adsorbed hydrogen on the N2 adsorption and N2 isotope displacement rate on Ru/MgO and Ru–Cs+/MgO were investigated by FTIR. The H2 was found to be adsorbed dissociatively on on-top sites [1880w(sh), 1801w(sh), and 1717s cm−1], bridging sites [1550w and 1330w cm−1], and threefold sites [1120m and 933m cm−1] on Ru/MgO, and similarly on three kinds of adsorption sites on Ru–Cs+/MgO. The bridging hydrogen on Ru/MgO was thermally more stable than the other two. Molecular N2 could be adsorbed as an on-top form on Ru. By the small amount of preadsorbed H(a) [H(a)/Rusurf = 14%], the N2 isotope displacement rate 15N2(a) → 14N2(a) in 14N2 on Ru/MgO was largely reduced to 12%, and the reduction on Ru–Cs+/MgO was more serious (to 4%). The main factors of these reductions were interpreted as direct repulsion of H(a) and N2 on Ru/MgO and Ru-hydride dipole effect enhanced by doped Cs+ on Ru–Cs+/MgO. The common factors in N2 displacement reaction and the catalysis from N2 are discussed in terms of the hydrogen effect.
  • Ryotaro Kiyono, Masayasu Tasaka, Masanobu Nagura
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3201-3204
    Published: 1994
    Released: August 01, 2006
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    The dependence of the streaming potential across hydrogel membranes on time was measured. The gel membranes used were obtained by blending various amounts of poly(vinyl alcohol) and poly(sodium L-glutamate), which have different average molecular weights per cross-linked unit. The streaming potential increased rapidly just after applying a pressure difference and then increased gradually up to a steady-state value. The time dependence of the streaming potential was analyzed as the relaxation of the polymer chains dissolved in the liquid phase of the membrane. The relaxation for all the gel membranes consisted of a single component. The relaxation time was long if the gel had a large average molecular weight per cross-linked unit. The effects of cross-linking and the concentration of the external solution on the relaxation time are discussed.
  • Shuichi Naito, Mitsutoshi Tanimoto
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3205-3211
    Published: 1994
    Released: August 01, 2006
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    The mechanism of propene–deuterium reaction over unsupported and silica-supported ZrO2 catalysts was studied with kinetic investigation as well as microwave spectroscopic analysis of monodeuteriopropene. Unsupported ZrO2 exhibited the identical catalytic behavior for C3H6–D2 reaction with other oxide catalysts previously reported: Only propane-d2 was selectively formed in the addition process, with no hydrogen exchange in propene. By supporting on silica, the rate of C3H6–D2 reaction increased considerably, with the decrease of activation energy. Hydrogen exchange in propene proceeded simultaneously with addition via associative mechanism through propyl and isopropyl intermediates. Small particles of ZrO2 were proposed as active sites of this characteristic catalytic behavior.
  • Hiroaki Isago, Yutaka Kagaya
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3212-3215
    Published: 1994
    Released: August 01, 2006
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    The redox potentials of the titled complexes, [Bi(pc)X] (pc2− = phthalocyaninate, C32H16N8 2−, and X = Cl and Br), in N,N-dimethylformamide solutions have been determined by cyclic voltammetry for the first time as phthalocyanine complexes of group-15 elements. The voltammograms of [Bi(pc)Cl] consisted of one oxidation (E1/2 = 0.36 V vs. ferrocene/ferricinium+) and two reduction couples (ca. −1.2 and ca. −1.0 V), each of which was a quasi-reversible one-electron process. The voltammograms of [Bi(pc)Br] were quite similar to those obtained with [Bi(pc)Cl], with the exception of the appearance of an additional irreversible anodic peak at 0.30 V, which could be attributable to the oxidation of non-ligand bromide, suggesting the dissociation of [Bi(pc)Br] into [Bi(pc)]+ and Br in DMF. This is the first case in which [M(pc)X]-type (M = trivalent metal) complex dissociated into [M(pc)]+ and X in solution.
  • Abdel-Aziz Youssef El-Sayed
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3216-3223
    Published: 1994
    Released: August 01, 2006
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    The determination methods of the gold(III) and silver(I) with, 5-(4-hydroxy-3-methoxybenzylidene) rhodanine (3,4-MHBR) in the presence of benzyldimethyltetradecylammonium chloride (zephiramine), and 5(3,4-dihydroxybenzylidene) rhodanine (3,4-DHBR) in the presence of cetyltrimethylammonium bromide (CTAB) have been described. The application of first- and second-derivative spectrophotometry to simultaneous determination of gold(III) and silver(I) in their mixtures have been assayed using “zero-crossing” technique of measurement. In the pH ranges 8.8—9.8 and 9.0—10.2 the ternary 1 : 3 : 3 and 1 : 2 : 2 complexes gold(III)-3,4-MHBR-zephiramine and silver(I)-3,4-MHBR-zephiramine have been formed with molar absorptivities of 4.98 × 104 and 4.64 × 104 dm3 mol−1 cm−1 at 529 and 522 nm, respectively. The ternary 1 : 3 : 4 and 1 : 2 : 3 complexes gold(III)-3,4-DHBR-CTAB and silver(I)-3,4-DHBR-CTAB have been formed in the pH ranges 9.4—10.2 and 9.0—10.5 with molar absorptivities of 8.63 × 104 and 7.76 × 104 dm3 mol−1 cm−1 at 560 and 555 nm, respectively. The first- and second-derivative spectra of these complexes allow the determination of one metal in the presence an excess of the other. Gold(III) (0.21—3.6 μg cm−3) and silver(I) (0.12—2.63 μg cm−3) in different ratios have been determined simultaneously with good precision and accuracy using the proposed methods. The statistical analysis of the experimental results are presented. The methods have been applied to simultaneous determination of gold and silver in silicate rocks.
  • Junichi Yamada, Haruki Hashimoto, Yoshie Inomata, Toshio Takeuchi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3224-3230
    Published: 1994
    Released: August 01, 2006
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    Eight cadmium(II) halide complexes with N-methylglycine (sarcosine, Hsar), N,N-dimethylglycine (Hdmgly), and N,N,N-trimethylglycine (betaine, Hbet) have been prepared and characterized by using their infrared absorption spectra and thermal analyses. In addition, the crystal and molecular structures of [CdCl2(Hsar)] (1) and [CdCl2(Hdmgly)(H2O)2] (2) were determined by a single-crystal X-ray diffraction method. The crystal data for these two complexes are as follows: Complex (1): monoclinic, space group P21/n, a = 7.960(2), b = 13.844(1), c = 6.917(1) Å, β = 92.42(2)°, Z = 4. Complex (2): monoclinic, space group P21/a, a = 7.696(2), b = 21.854(4), c = 6.253(2) Å, β = 103.69(2)°, Z = 4. These structures were solved by the heavy-atom method and refined by full-matrix least-square methods to final R values of 0.043 for 2533 reflections about 1 and 0.068 for 3615 reflections about 2, respectively. For 1 the structure consists of a one-dimensional polymer bridged by two chlorine atoms. The cadmium atom is hexa-coordinated, being ligated with two oxygen atoms of a carboxyl group and four chlorine atoms. For 2 the cadmium atom is in a distorted octahedral geometry, ligated by a carboxylato oxygen atom, two water molecules, and three chlorine atoms, in which one is terminal and the other two are bridging cadmium atoms to make a polymer.
  • Masanao Kato, Terunori Nakano, Toshiaki Hattori
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3231-3235
    Published: 1994
    Released: August 01, 2006
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    Adsorptions of twelve β-diketones and their copper(II) complexes onto an octadecyl-bonded silica gel from an aqueous solution were measured by a batch technique. Several equilibrium constants for the adsorption reaction were measured and compared with those for solvent extraction. Using these constants, the abundance of each chemical species containing copper(II) ion in the presence of 2,4-pentanedione was calculated with respect to both the aqueous and the ODS gel phase.
  • Bhim Bali Prasad, Sandhya Singh
    1994 Volume 67 Issue 12 Pages 3236-3244
    Published: 1994
    Released: August 01, 2006
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    The electrochemical behavior of a redox polyelectrolyte, poly[4,4′-bipyridinium-1,1′-diylcarbonyl-2,5-thiophenediyl dichloride] at mercury electrode has been examined in dimethyl sulfoxide containing different concentrations of tetrabutylammonium iodide. The techniques of sampled DC polarography, pulse polarography (normal and differential), and cyclic voltammetry have been used. All polarograms revealed three one-electron reduction waves which are found either quasi-reversible or irreversible and usually adsorption-controlled by cyclic voltammetric experiments. The results were discussed by taking into account the implications of different concentrations of supporting electrolytes and polycation conformations on the adsorption processes consisting of preceding and following chemical reactions coupled with charge transfer reactions occurring at the electrode.
  • Kisaburo Umemoto, Yutaka Nagase, Yukio Sasaki
    1994 Volume 67 Issue 12 Pages 3245-3248
    Published: 1994
    Released: August 01, 2006
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    In aprotic solvents, the reaction of hydroxide ion with electron acceptors — iodine, tetracyanoquinodimethane, Nitro Blue Tetrazolium, methylviologen, 2,3,5-triphenyltetrazolium chloride, duroquinone, anthraquinone, benzil, 9-fluorenone, perylene — gave reaction products identical to those obtained by the reduction of these electron acceptors with electron donors. The paths of reaction of these electron acceptors with hydroxide ion were found to be composed of successive one-electron reactions. The efficiency of the reaction showed a good correlation with the reduction potential of the electron acceptors; the rate of the reaction decreased with increasing the reduction potential of the electron acceptors.
  • Tomoji Ozeki, Toshihiro Yamase, Haruo Naruke, Yoshinori Sasaki
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3249-3253
    Published: 1994
    Released: August 01, 2006
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    Direct evidence for the locations of the hydrogen atoms in the dihydrogenhexaniobate anion has been obtained by a single-crystal X-ray diffraction method. Hexasodium dihydrogenhexaniobate icosahydrate (1), Na6[H2Nb6O19]·20H2O, crystallizes in triclinic form, space group , a = 10.364(2), b = 12.205(2), c = 9.026(2) Å, α = 103.21(2), β = 111.10(2), γ = 109.27(2)°, V = 924.0(5) Å3, Z = 1. The hexaniobate anion in 1 is protonated at two bridging oxygen atoms with the O–H distance of 0.69(6) Å. Due to the protonation and interactions with the Na+ counter-cations, the point symmetry of the hexaniobate anion is reduced to C2h from its possible highest symmetry of Oh.
  • Debasis Das, Ashutosh Ghosh, Nirmalendu Ray Chaudhuri
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3254-3259
    Published: 1994
    Released: August 01, 2006
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    [NiL3]I2·2H2O [L = N–methylethane–1,2–diamine (meen) and 2-methylpropane-1,2-diamine (ibn)], [NiL3]I2 [L = ethane–1,2–diamine (en), N-ethylethane-1,2-diamine (eten), N-propylethane-1,2-diamine (pren), and propane-1,2-diamine (pn)], [NiL2(H2O)2]I2 (L = meen and eten), and [Ni2L2]I2 [L = N-isopropylethane-1,2-diamine (ipren) and ibn] have been synthesized from solution and characterized. [NiL2I2] (L = en, meen, eten, and pren] and [Ni(ibn)2]I2 have been isolated in the solid state from their corresponding parent tris(diamine) complex by temperature arrest technique. [NiL2(H2O)2]I2 (L = meen and eten) upon heating undergo deaquation-anation reaction. All the diamine species excepting [Ni(ipren)2]I2 and [Ni(ibn)2]I2 which possess square-planar geometry, are octahedral and both the diaqua and diiodobis(diamine) species possess trans-octahedral geometry showing variation only in [Ni(en)2I2], which is having cis-octahedral geometry. [Ni(meen)2I2] and [Ni(eten)2I2] show irreversible endothermic phase transitions (160—190 °C; ΔH = 5.65 kJ mol−1 and 204—225 °C; ΔH = 4.23 kJ mol−1, respectively) without any visual color change with retention of trans-octahedral configuration. In case of [Ni(eten)2I2] the post phase species reverts to the original diaqua species, [Ni(eten)2(H2O)2]I2 on keeping in open atmosphere whereas the rehydrated species of its meen analogue, [Ni(meen)2(H2O)2]I2 after deaquation does not show the phase transition. On the other hand, corresponding pren analogue shows reversible endothermic phase transition (68—111 °C; ΔH = 2.42 kJ mol−1 for heating and 98—77 °C; ΔH = −1.4 kJ mol−1 for cooling). The occurrence of this type of phase transition is due to the conformational changes in the diamine chelate rings. The square-planar [Ni(ibn)2]I2 undergoes time dependent reversible phase transition (232—248 °C; ΔH = 5.99 kJ mol−1) without any visual color change retaining the original geometry. Here also conformational changes in chelate rings are assumed to be responsible for this transition.
  • Hiroshi Kawamoto, Hideyuki Itabashi, Kiyomi Urano
    1994 Volume 67 Issue 12 Pages 3260-3262
    Published: 1994
    Released: August 01, 2006
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    A synergistic extraction of iron(II) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TTA) and pyridine base was studied in order to clarify the effect of light and shade on the extraction. The extraction constant obtained at a shady place was larger than that obtained at a light place when pyridine or 4-methylpyridine was used as an additive. The stability constants for synergistic adducts at both places were almost the same, and hence it was concluded that the light and shade effect occurs in bonds between the central iron(II) and TTA anions.
  • Masahiro Mikuriya, Fumiya Adachi, Hirofumi Iwasawa, Makoto Handa, Masa ...
    1994 Volume 67 Issue 12 Pages 3263-3270
    Published: 1994
    Released: August 01, 2006
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    Manganese(II) complexes with 2-[(2-aminoethyl)amino]ethanethiol (HLa), 2-[(3-aminopropyl)amino]ethanethiol (HLb), 2-[(2-pyridylmethyl)amino]ethanethiol (HLc), and 2-[[2-(2-pyridyl)ethyl]amino]ethanethiol (HLd)–[Mn(La)Cl]n (1), [Mn{Mn(Lb)2}2]Cl2·2CH3OH (2), [Mn(Lc)Cl]n (3), and [Mn(Ld)Cl(CH3OH)]n (4) have been synthesized and characterized by elemental analyses, infrared and electronic spectroscopies, and magnetic susceptibilities (80—300 K). The crystal structures of all these complexes were determined by the single-crystal X-ray diffraction method. Complexes 1 and 3 have a thiolate-bridged polymeric chain structure in which each manganese atom is five-coodinated in a trigonal bipyramid. Complex 2 is a thiolate-bridged trinuclear manganese(II) complex displaying a linear arrangement of the three manganese atoms with the two Mn–Mn interactions being equidistant [3.420(1) Å]. Complex 4 is a thiolate-bridged polymeric infinite chain showing a distortion in the octahedral geometry around each manganese atom. The magnetic properties are discussed in relation to the crystal structures.
  • Kohtaro Osakada, Takakazu Yamamoto
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3271-3275
    Published: 1994
    Released: August 01, 2006
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    [Rh(PMe3)4]Cl reacts with HSPh to give cationic hydrido(benzenethiolato)rhodium complex, cis-[RhH(SPh)(PMe3)4]Cl (1). The NMR (1H, 31P{1H}, and 13C{1H}) spectra as well as elemental analyses of 1 indicate the octahedral coordination with a hydrido and an SPh ligand at mutually cis positions. Reaction of [Rh(PMe3)4]Cl with HSPh in the presence of NEt3 gives a mixture of mer-RhCl(H)(SPh)(PMe3)3 (2) (38%) and [Rh2(μ-SPh)2(PMe3)4] (3) ( < 20%). X-Ray crystallography has revealed the molecular structure of 2, which has slightly distorted octahedral coordination around the Rh center with three PMe3 ligands at meridional coordination sites. The hydrido ligand, which is at a distance of 1.52 Å from the Rh center, is at trans position to Cl and cis position to the SPh ligand. Complex 1 reacts with equimolar MeI to give MeSPh in 86% yield.
  • Morio Yashiro, Makoto Komiyama, Kana Kuroda, Shuji Miura, Sadao Yoshik ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3276-3281
    Published: 1994
    Released: August 01, 2006
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    Cobalt(III) complexes containing an optically active 14-membered cyclic tetraamine (R,R-Me6[14]aneN4, 7(R), 14(R)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) and a bidentate ligand (glycinato, S-alaninato, or oxalato), in which the tetraamine takes the folded cis-type configuration, were prepared and characterized by elementary analyses, 1H and 13C NMR spectroscopy, and circular dichroism spectroscopy. Electronic absorption and 59Co NMR spectroscopies indicate that stereochemical modification of the 14-membered cyclic ligand with C-methyl groups causes an unusual decrease in the ligand field strength of the complex. Rapid dissociation of the chelated alaninato ligand from the cobalt(III) complex, which is generally inert, was observed for the [Co(S-alaninato)(R,R-Me6[14]aneN4)]2+ complex system. The dependence of the dissociation of the alaninato chelate on the ligand field strength is strongly suggested.
  • Yozo Miura, Yuichi Kitagishi, Sadaharu Ueno
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3282-3288
    Published: 1994
    Released: August 01, 2006
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    Three N-(Arylthio)-2,4,6-tris(4-methylphenyl)-, three N-(arylthio)-2,4,6-tris(3-chlorophenyl)-, and five N-(arylthio)-2,4,6-tris(4-chlorophenyl)phenylaminyl radicals have been generated by PbO2 oxidation of the corresponding N-(arylthio)-2,4,6-triarylanilines and their isolation has been carried out. When electron-donating methyl groups were substituted at the p-positions of the 2,4,6-triphenyl groups, the aminyls were less stable, and only one could be isolated as radical crystals. On the other hand, when chloro atoms were substituted at the m- or p-positions of the 2,4,6-triphenyl groups, the aminyls were more stable and most were isolated. The isolated radical crystals were stable for a long period without any decomposition. The spin density distributions in the radicals are discussed on the basis of the ESR parameters.
  • Sukalyan Dash, Bijay K. Mishra
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3289-3296
    Published: 1994
    Released: August 01, 2006
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    The oxidation of N-alkyl substituted styrylpyridinium bromides in both KMnO4 and cetyltrimethylammonium permanganate (CTAP) results in the formation of corresponding substituted benzaldehydes. The oxidation in aqueous medium is catalyzed by acid whereas in chloroform medium the reaction proceeds at neutral condition. However, the reaction proceeds through the same mechanism in both the media. The faster rate of oxidation in aqueous medium by KMnO4 than that in chloroform medium by CTAP has been rationalized through hydrophobic effect. The overall rate equation can be represented as rate = k[Substrate]1.5[Oxidant]−0.75 in aqueous medium and rate = k[Substrate]0.5[Oxidant]−1 in chloroform medium. From the substituent effect a transition state with low electron density at the olefinic carbon has been proposed.
  • Yasushi Yokoyama, Tetsushi Inoue, Masato Yokoyama, Takakazu Goto, Take ...
    1994 Volume 67 Issue 12 Pages 3297-3303
    Published: 1994
    Released: August 01, 2006
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    Furylfulgides with different sizes of alkyl substituents were synthesized and their photochromic properties were examined. While the quantum yield of coloring reaction increased and the quantum yield of the E-to-Z isomerization decreased as the steric bulkiness of the alkyl substitutent on the 2,5-dimethyl-3-furylmethylidene moiety increased, the bleaching quantum yield increased as the isopropylidene group was replaced by an adamantylidene group. Both effects worked independently, and a furylfulgide with an isopropyl group on the furylmethylidene moiety and an adamantylidene group in one molecule showed the coloring quantum yield of 0.51 (366 nm) and the bleaching quantum yield of 0.26 (492 nm) in toluene.
  • Toshiaki Itozawa, Hideo Kise
    1994 Volume 67 Issue 12 Pages 3304-3308
    Published: 1994
    Released: August 01, 2006
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    The effects of alcohol structure and reaction conditions on the horse liver alcohol dehydrogenase-catalyzed reduction of cyclohexanone were investigated with in situ regeneration of NADH by alcohols. The rate of coupled reduction of cyclohexanone was much more strongly affected by the structure of alcohols than the reduction rate of NAD measured in the absence of cyclohexanone. Diols such as 1,4-butanediol or 1,5-pentanediol were the reductants of choice in terms of reaction rate and the yield of cyclohexanol. The effects of pH and buffer concentration on coupled reduction of cyclohexanone were parallel to the effects on NAD reduction. However, the dependency of coupled reduction of cyclohexanone on reaction temperature reflected the temperature-dependency of cyclohexanone reduction by NADH in the absence of alcohols. These results were discussed in terms of the difference of sensitivity to the reaction conditions of each oxidoreduction and of coupled oxidoreductions.
  • Yoo Tanabe
    1994 Volume 67 Issue 12 Pages 3309-3313
    Published: 1994
    Released: August 01, 2006
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    Various 1-alkynes were converted to 1-alkoxy-3-chloro-2-alkenes using alkoxymethyl esters and dichlorobis(trifluoromethanesulfonato)titanium(IV) [TiCl2(OTf)2, titanium(IV) bis(triflate)]. This carbon homologation proceeded in the case of not only simple 1-alkynes but also for several 3- or 4-dimethylcarbamoyloxy-, 5-benzoyloxy-, 5-phenoxycarbonyloxy-, and 5-methoxycarbonyloxy-1-alkynes. Among them, 3- and 4-dimethylcarbamoyloxy-1-butynes underwent the reaction without loss of their functionalities compared with the other oxy substrates. The stereoselectivity was Z predominant, especially in the case of the above mentioned 3-, 4-, and 5-oxy substituted 1-alkynes. Addition of TiCl4 to this system was somewhat effective for enhancing the Z ratios. Titanium(IV) bis(triflate) was the only effective catalyst among several Lewis acids such as AlCl3, TiCl4, SnCl4, ZnCl2, and Sn(OTf)2. As a functionalization of the obtained vinyl chloride, 3-chloro-4-dimethylcarbamoyloxy-1-methoxy-2-pentene was converted into the corresponding ketone using Hg(OCOCF3)2.
  • Kohji Ishihara, Nobuyoshi Nakajima, Sadao Tsuboi, Masanori Utaka
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3314-3319
    Published: 1994
    Released: August 01, 2006
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    An α-acetoxy ketone reducing enzyme has been purified and characterized from the cell-free extract of bakers’ yeast (Saccharomyces cerevisiae). Only one NADPH-dependent dehydrogenase that catalyzed the reduction of α-acetoxy ketone was found in bakers’ yeast. The molecular weight of the enzyme was estimated to be 36 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme was composed of a single polypeptide chain. The enzyme had reducing activity for both aliphatic and aromatic α-acetoxy ketones, although no reducing activity toward α-chloro ketones and α-hydroxy ketones was found. The enzyme catalyzed the reduction of not only α-acetoxy ketones, but also β-keto esters. Studies on the chromatographic behavior and stereospecificity indicated that the enzyme was identical with one of the β-keto ester reductases purified from bakers’ yeast.
  • Hla Ngwe, Hideki Kinoshita, Katsuhiko Inomata
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3320-3326
    Published: 1994
    Released: August 01, 2006
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    Diethyl 3,4-disubstituted 1,5-dihydro-5-oxo-2H-pyrrol-2-ylphosphonates were regioselectively prepared by acidic hydrolysis of diethyl 3,4-disubstituted 5-bromo-2-pyrrolylphosphonates. The resulting 1,5-dihydro-2H-pyrrol-2-ones readily underwent the coupling reaction with various aldehydes to afford the corresponding 1,5-dihydro-5-methylene-2H-pyrrol-2-ones including pyrromethenone derivatives in good yields. A series of these reactions was successfully applied to the synthesis of C/D-rings component of phycocyanobilin.
  • Ichiro Yamamoto, Koichi Narasaka
    1994 Volume 67 Issue 12 Pages 3327-3333
    Published: 1994
    Released: August 01, 2006
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    (+)-Paniculide A, a highly oxidized sesquiterpene, has been synthesized enantioselectively starting from a cycloadduct, which was prepared from 3-(3-borylpropenoyl)-1,3-oxazolidin-2-one and 1-acetoxy-3-methyl-1,3-butadiene by a catalytic asymmetric Diels–Alder reaction.
  • N. John Jebarathinam, M. Eswaramoorthy, V. Krishnasamy
    1994 Volume 67 Issue 12 Pages 3334-3338
    Published: 1994
    Released: August 01, 2006
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    NiCr2O4, ZnCr2O4, CuCr2O4, CuAl2O4, and CuFe2O4 were prepared and characterized by XRD, DRS, and IR and by measurements of surface area, acidity, and electrical conductivity. XRD analysis indicates, that chromites, aluminate, and ferrite have normal, partially inversed, and inversed spinel structure, respectively. Electrical conductivity measurements show the existence of pair localized ions which are positive in chromites and negative both in aluminate and ferrite. The catalytic activity of chromites and aluminate are comparable and higher than that of ferrite in the conversion of ethylbenzene under all experimental conditions. However selectivity to styrene formation follows in the following order: ferrite > chromites > aluminate. The ratio of B/T (benzene/toluene) is more than unity over aluminate and less than unity over chromites and ferrite. Evolution of CO2 remains constant while that of C2H4 increased with increase in temperature keeping its formation always higher over aluminate. Measurements of acidity and basicity by TGA show the presence of basic sites on chromites, acidic sites on aluminate, and both sites on ferrite which influence the conversion of ethylbenzene to various products. The XRD pattern of spent catalysts indicate the appearance of metallic copper phase over CuCr2O4, CuFe2O4, and CuAl2O4. In the case of NiCr2O4 and ZnCr2O4 no significant difference is observed.
  • Shigeru Sugiyama, Takashi Ookubo, Kazuaki Shimodan, Hiromu Hayashi, Jo ...
    1994 Volume 67 Issue 12 Pages 3339-3345
    Published: 1994
    Released: August 01, 2006
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    The oxidative coupling of benzene has been compared with that of methane on La2O3, CeO2, Pr6O11, and Sm2O3. At temperatures greater than 1048 K, the gas phase oxidative coupling of benzene appears to be predominant, while the oxidation occurs catalytically at 873 K. The conversion of benzene and of methane at 873 K follows the order of Sm2O3 > La2O3 > Pr6O11 > CeO2, suggesting that the abstraction of hydrogen from the aromatic and the saturated compounds depends primarily on the nature of the catalyst but not the reactant. Ancillary information has also been obtained from the results of XPS analyses of both fresh catalysts and those previously used in one of the reactions.
  • Yoshio Sugiyama, Yasushi Suzuki, Shuichi Mitamura, Yugen Kawamoto, Mak ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3346-3348
    Published: 1994
    Released: August 01, 2006
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    The second-order optical nonlinearities and transparencies of eight substituted styrenes containing at least one sulfonyl group at the β-position, as the electron-withdrawing group, were examined. Oxidation at a sulfur atom (SMe → SOMe → SO2Me) brings about increases in the β and λmax values.
  • Tapash K. Barman, Babul C. Paul, Kochi Ismail
    1994 Volume 67 Issue 12 Pages 3349-3351
    Published: 1994
    Released: August 01, 2006
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    Visible absorption spectra of Methyl Red in buffered benzene–water microemulsions (MEs) stabilized by sodium dodecyl sulfate and 1-butanol were recorded at 25 °C and at various pH values. Three compositions of the ME were used with R = 24, 32, and 48 where R is the water (aqueous buffer)-to-surfactant molar ratio. pKaof Methyl Red is found to be 6.12, 6.38, and 6.6 in MEs of R = 24, 32, and 48, respectively. The effective dielectric constant of the ME is estimated to be about 45 ± 3.
  • Kimiharu Endo, Yoshiyuki Sugahara, Kazuyuki Kuroda
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3352-3355
    Published: 1994
    Released: August 01, 2006
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    In this study, n-alkyltrimethylammonium ions ([CnH2n+1N(CH3)3]+; n = 12,14,16,18) were intercalated in the interlayer space of layered sodium octosilicate (Na2Si8O17·nH2O) via an ion-exchange reaction. The interlayer space was further modified by grafting of the trimethylsilyl groups via a reaction between a dodecyltrimethylammonium–octosilicate intercalation compound and chlorotrimethylsilane.
  • Bunji Uno, Noriko Okumura, Satoshi Kawai
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3356-3359
    Published: 1994
    Released: August 01, 2006
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    In a reversed-phase high-performance liquid-chromatographic analysis phthalic acid and terephthalic acid were observed as two clearly separated peaks with a mobile phase of pHs around the second pKa values involving the monoanion and dianion species.
  • Shuji Emori, Chikako Date
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3360-3362
    Published: 1994
    Released: August 01, 2006
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    Copper(II) compounds: CuCl2[C5H5NCH2COO]·3H2O, CuCl2[C5H5N(CH2)nCOO]·2H2O (n = 2, 3), and CuCl2[C5H5N(CH2)nCOO]2 (n = 1—3) were prepared. Then they were characterized by means of magnetic susceptibility and IR spectroscopy. The equilibria between mono- and dinuclear species in their aqueous solutions were studied using magnetic susceptibility measurements. The tendency for adopting dinuclear species in water increased in the order: pyridinioacetate < 3-pyridiniopropionate < 4-pyridiniobutyrate.
  • Seiji Iwama, Shigeo Katsumura
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3363-3365
    Published: 1994
    Released: August 01, 2006
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    The reaction of (S)-4-tosyloxymethyl-2-oxazolidinone, which was synthesized from (R)-glycidol through (R)-4-benzoyloxymethyl-2-oxazolidinone, with various lithium dialkylcuprate(I)s in THF proceeded smoothly to afford the corresponding protected amino alcohol derivatives in good yield.
  • Tyo Sone, Yoshitomo Kobori, Yuji Ando, Yoshihiro Ohba
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 12 Pages 3366-3369
    Published: 1994
    Released: August 01, 2006
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    Acyclic phenol–formaldehyde tetramer and hexamer analogs containing 2,2′-dihydroxybiphenyl or 2,2′-dihydroxy-1,1′-binaphthyl unit as a central building block were synthesized. The tetramer analogs preferentially formed crystalline inclusion complexes with aromatic guests as the parent p-t-butylphenol–formaldehyde tetramer; those with the binaphthol unit were superior for complexation.
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