Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 67 , Issue 4
Showing 1-50 articles out of 51 articles from the selected issue
  • Fulvio Corradini, Luigi Marcheselli, Andrea Marchetti, Mara Tagliazucc ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 899-905
    Published: 1994
    Released: July 13, 2006
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    For many multicomponent cosolvent systems which can be important in electrochemical studies as far as in practical applications, the relative permittivity (ε) is a continuous but nonlinear function of the solvent composition. Rational functions were applied to the 1,2-ethanediol (1) + 2–methoxyethanol (2) + water (3) ternary mixtures data at various temperatures (50 ≤ t/°C ≤ 80) instead of the more conventional polynomial regressions for ε = ε(Xi). These rational functions seem to be more adequate than the other polynomials, being reduced the number of required adjustable coefficients; in fact only a first power dependence on mole fraction (Xi) is necessary, and a computational simplicity in reproducing reliable ε values over the total mole fraction 0 ≤ X1/X2/X3 ≤ 1 range is achieved. Furthermore, the calculated excess function (εE) is always negative, confirming the existence of rather strong interaction between components, probably via hydrogen bonding networks. Changes with temperature in εE for these ternary mixtures seem to be very useful in order to depict and differentiate the experimental trend in three well distincted regions (namely MI,MII,MIII) which are likely characterized by different specific interactions between like and/or unlike species. Nevertheless, no evidence for a three component adduct was obtained.
  • Seiji Yamasaki, Hisao Tsutsumi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 906-911
    Published: 1994
    Released: July 13, 2006
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    1,3 : 2,4-Di-O-benzylidene-D-sorbitol (D-DBS) is known to be a chiral oil gelator which forms the gel state with organic solvents having a wide range of polarities. Microscopic and thermoanalytical studies on the binary system, D-DBS/ethylene glycol, were carried out. The gel of the D-DBS/ethylene glycol system showed optical anisotropy under crossed polarizers. Two kinds of mesophases have been identified in the gel state. One was the crystalline phase, by means of observing the spherulitic texture. The other was an isotropic mesophase between spherulitic textures. In the crystalline phase the supramolecular helicoidal strucrture was observed by polarized and electron microscopy. The isotropic mesophase comprized of a network-like structure. It changed to the crystalline phase below the phase transition temperature from a gel to an isotropic solution (Ti), and the crystal of D-DBS was precipitated out from ethylene glycol. It is thus concluded that the gel state of D-DBS/ethylene glycol is a metastable state and that the chirality of D-DBS affects the shape which D-DBS forms in the crystalline state.
  • Koji Saito, Emi Hattori, Munekazu Nozaki, Akihiro Yoshino, Kensuke Tak ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 912-917
    Published: 1994
    Released: July 13, 2006
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    The 1H and 13C NMR spectra of some A3A′3 spin molecules dissolved in a nematic phase of EBBA were analyzed. The relative internuclear distances, orientation parameters, and internal motions about the symmetry axes of two methyl groups were obtained and are discussed.
  • Hiroto Osaka, Takayuki Ishida, Takashi Nogami, Ritsuko Yamazaki, Masan ...
    1994 Volume 67 Issue 4 Pages 918-923
    Published: 1994
    Released: July 13, 2006
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    A series of ethylene and methanimine derivatives possessing both electron-donor and -acceptor groups were synthesized in order to obtain frequency doublers of infrared semiconductor lasers. Their second-harmonic-generation (SHG) was investigated by means of a powder method and an electric-field-induced second-harmonic method. Three ethylene derivatives were found to be SHG active without any absorption in the blue wavelength region. X-Ray crystallographic analyses were made for two of them. It was found that strong donor and acceptor substituents tend to twist the central C=C double bond, thereby resulting in smaller β-values than those expected for non-twisted molecular structures. Based on the molecular and crystal structures, some strategies are presented regarding the synthesis of SHG materials of these push-pull ethylenes and methanimines.
  • Shigeru Ohshima, Akira Uchida, Seiji Horiguchi, Atsushi Suzuki, Shoji ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 924-928
    Published: 1994
    Released: July 13, 2006
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    The photooxygenation of diphenanthro[5,4,3-abcd : 5′,4′,3′-jklm]perylene (DPP) due to visible-light irradiation was investigated by measuring the absorption spectra and applying semi-empirical molecular orbital methods. It was shown theoretically that molecular oxygen attaches to the central benzene ring of DPP to give an endo-peroxide. The oxygen gradually detaches from the endo-peroxide at room temperature, reproducing DPP. The activation energies for both the reactions of oxygen attachment and detachment were determined based on the temperature dependences of the reaction rates in benzene; 10.0 ± 5.5 kJ mol−1 for the attachment reaction and 83.8 ± 2.5 kJ mol−1 for the detachment reaction.
  • Yasuo Kameda, Hidekazu Ebata, Osamu Uemura
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 929-935
    Published: 1994
    Released: July 13, 2006
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    The Raman spectra for concentrated aqueous LiBr solutions (LiBr)x(H2O)1−x and (LiBr)x(D2O)1−x, x = 0.05—0.25, were measured in the frequency range of 30—1000 cm−1. A polarized peak intensity centered at 160—190 cm−1 in the isotropic spectrum for H2O solutions exhibits a systematic increase with increasing LiBr content. At LiBr concentrations below 15 mol%, this peak contains several shoulders at both the lower and higher frequency sides. The corresponding peak in the isotropic spectrum for D2O solutions is shifted to the lower frequency by ca. 10 cm−1. The isotropic spectra for highly concentrated H2O solutions, such as 20 and 25 mol% LiBr, have another component at 340 cm−1, which is also shifted to the lower frequency by ca. 20 cm−1 in D2O solutions. This 340 cm−1 peak in a 25 mol% LiBr solution is also shifted to the higher frequency by ca. 13 cm−1 when isotopically substituting 6Li (95.5% 6Li) for natLi (92.5% 7Li), while the position of 190 cm−1 peak remains unchanged when substituting. Consequently, the peaks centered at 160—190 cm−1 and at 340 cm−1 can, respectively, be assigned to the totally symmetric stretching vibration of tetrahedrally hydrated lithium ion, Li+(H2O)4, and that of the solvent-shared ion pair, Li+(H2O)4···Br, by taking into consideration the results of diffraction studies reported previously.
  • Tsugitoshi Ogura, Masazumi Tanoura, Kiyoshi Tatsuhara, Akio Hiraki
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 936-941
    Published: 1994
    Released: July 13, 2006
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    The flow properties of montmorillonite, one of the main clay components in coal, were studied in water suspensions to clarify the origins of the Bingham flow properties of coal water slurry (CWM) in the presence of a surfactant. The addition of anionic surfactants, such as sodium poly(isoprenesulfonate) and sodium polycarbonate, significantly decreased the apparent viscosity and Bingham yield value of the montmorillonite suspension, although the latter value never became zero, even when a large quantity of surfactant was added. The amount of water bound to montmorillonite particles, measured using 1H NMR, was found to increase with the addition of a surfactant. The Bingham yield value and the relative viscosity of the montmorillonite suspension were described by Michaels’ equation, τB = A(SφSφ0)3 (Eq. 6), and by the modified Brinkman’s equation, ηr = (1 − )k (Eq. 8), respectively. In both equations, the sum volume of montmorillonite particles and its bound water () is correlated to the flow properties through constants A and k. A reduction of both A and k suggests two different actions of the anionic surfactants in the montmorillonite suspension. A decrease in the A value indicates a reduction of the strength of the aggregate networks of montmorillonite at a low shear rate, while a decrease in the k value shows that the shape of the effective montmorillonite particle becomes more spherical due to an increase of bound water.
  • Taishi Kuri, Yushi Oishi, Tisato Kajiyama
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 942-947
    Published: 1994
    Released: July 13, 2006
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    The area-creep mechanism for the crystalline monolayer of stearic acid on the water surface was discussed on the basis of area-creep measurements and transmission electron microscopic observations. The area-creep behaviors of the crystalline monolayer at a high surface pressure region (≥ 15 mN m−1) was apparently different from those at a low one (≤ 10 mN m−1). At a high surface pressure region, the area-creep behavior of the monolayer was mainly classified into the two processes in shorter and longer creep time regions with respect to around 1 × 102 s. The area strain in a short creep time region was small and increased linearly with the creep time, that might be attributed to rearrangement of molecules in the crystalline monolayer during the area-creep (molecular creep). On the other hand, the area strain in a long creep time region increased remarkably owing to collapse of the monolayer (geometrical aggregation creep). Also at a low surface pressure region, the area strain was small and became almost constant at around 1 × 104 s after the area-creep experiment started. In the case of the area-creep of the crystalline monolayer at a low surface pressure, rearrangement of molecules in the crystalline monolayer and/or filling in vacancies of molecular level in the interfacial regions among the crystalline monolayer domains were proceeded with a creep time, and then, the crystallographical regularity in the monolayer was increased owing to molecular rearrangement and/or sintering at an interfacial region among crystalline monolayer domains (molecular creep).
  • Takashi Kuboki, Koji Araki, Masaki Yamada, Shinsaku Shiraishi
    1994 Volume 67 Issue 4 Pages 948-955
    Published: 1994
    Released: July 13, 2006
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    New Cu(II), Ni(II), Co(II), and Pd(II) complexes of higher alkanoyl derivatives of 6,6′-diamino-2,2′-bipyridine were synthesized and their mesogenic properties were investigated. The Cu(II) complexes appear to exhibit a smectic C structure in their mesophase state.
  • Yasuo Kameda, Ryuji Takahashi, Takeshi Usuki, Osamu Uemura
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 956-963
    Published: 1994
    Released: July 13, 2006
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    Time-of-flight (TOF) neutron-diffraction measurements for 10 mol% NaSC14N and NaSC15N solutions in D2O were carried out in order to investigate the hydration structure around the thiocyanate ion, SCN. There are 1.8 ± 0.2 water molecules coordinated to SCN with an intermolecular distance of r(N···D) = 2.16 ± 0.02 Å, suggesting that the hydrogen bond is formed between SCN and the nearest-neighbor water molecules. It has also been indicated by pairing the neutron-diffraction and X-ray diffraction results that the angle between the molecular axis of SCN and the hydrogen bond, ∠C–N··· H2O, is ca. 120° in 10 and 20 mol% NaSCN aqueous solutions. Furthermore, details concerning the local structure around Na+ in these concentrated solutions have been proposed based on the results of a least-squares fitting between the observed and structural model functions.
  • Junko Takahashi, Takamasa Momose, Tadamasa Shida
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 964-977
    Published: 1994
    Released: July 13, 2006
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    The electronic structures of the phenoxyl radical in the electronic ground and excited states are studied by ab initio MO calculations. The geometries are optimized by the CAS-MCSCF procedure with the Huzinaga–Dunning DZV basis set. The electronic excitation energies and transition dipole moments are calculated by the CI procedure. According to the result of the calculation the observed absorption bands at about 600, 400, and 300 nm are assigned as , respectively. In order to analyze the vibrational character of the absorption band at about 400 nm the force constants, the potential energy distributions, the normal modes, and the Franck–Condon integrals are calculated for the three states, . The force constants are scaled by referring to the experimental resonance Raman, Trapped Ion Photodissociation (TIP), and the matrix-isolated electronic absorption spectra. The strongest vibrational band of the TIP and the absorption spectra is assigned to the 0–0 band of the transition and the second strongest, at a higher energy of 1110 cm−1, to the 0–0 band of the transition. The theoretical vibronic absorption and Raman spectra are reproduced and compared favorably with the experimental spectra.
  • Kazuo Sueoka
    1994 Volume 67 Issue 4 Pages 978-984
    Published: 1994
    Released: July 13, 2006
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    The magnetic susceptibilities of a number of liquids dissolving oxygen have been determined by an improved viscometer method at 298.15 K and 105.3 kPa; it has been confirmed that they are nicely expressed using the Wiedemann’s additivity law, and it is found that they are perfectly linear with the volume fraction of oxygen in the atmosphere in contact with liquids: a new-type law of susceptibility. It is shown that the effects of dissolved air are not canceled out unless the susceptibility of an oxygen-free liquid is used as the reference value, even when the solubilities of oxygen in the sample and the reference liquids are equal, causing a real error to an extent as much as 1.7%.
  • Daisuke Hashizume, Hidehiro Uekusa, Yuji Ohashi, Rikiya Matsugawa, His ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 985-993
    Published: 1994
    Released: July 13, 2006
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    The achiral N-isopropyl-N-methylphenylglyoxylamide molecule forms 1 : 2 host–guest complexes with the two kinds of the chiral host molecules derived from tartaric acid. The guest molecules in both of the clathrate crystals, I and II, are converted to the chiral β-lactam and oxazolidinone on exposure to a Hg lamp. The crystal structures of I and II, which are very similar to each other, were determined by X-rays: (I) Bis[(R,R)-(−)-trans-2,3-bis(diphenylhydroxymethyl)-1,4-dioxaspiro(4.4)nonane]N-isopropyl-N-methylphenylglyoxylamide, (C33H32O4)2·(C12H15NO2), fw = 1190.49, a = 10.404(2), b = 34.056(3), c = 9.434(3) Å, β = 94.87(2)°, V = 3331(1) Å3, Final R became 0.056. (II) Bis[(R,R)-(−)-trans-2,3-bis(diphenylhydroxymethyl)-1,4-dioxaspiro(4.5)decane]N-isopropyl-N-methylphenylglyoxylamide, (C34H34O4)2·(C12H15NO2), fw = 1218.54, a = 10.4616(5), b = 34.358(2), c = 9.469(4) Å, β = 94.798(3)°, V = 3391.4(3) Å3, Final R became 0.052. The guest molecule in each crystal is hydrogen bonded to the two host molecules. The absolute configurations of the chiral products seem to depend on the conformations of the guest molecules in I and II.
  • Tsuguo Ishihara, Katsuhisa Tanaka, Kazuyuki Hirao, Naohiro Soga
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 994-998
    Published: 1994
    Released: July 13, 2006
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    Transparent glass-ceramics containing LiGa5O8:Co2+ have been prepared by heat treatment of glass with a composition of 13Li2O·23Ga2O3·64SiO2·xCoO (0.1, 0.2, 0.5, 1.0) (mol%). The microstructure and the optical properties have been examined by using X-ray diffraction (XRD), transmission electron microscopy (TEM), and optical absorption measurements. XRD analyses indicated that LiGa5O8 microcrystals with a crystallite size of 5 to 10 nm precipitated in the specimens heat-treated at temperatures between 750 and 850 °C. Above 850 °C, LiGaSi2O6 crystals also precipitated. Heat treatment below 850 °C successfully yielded transparent glass-ceramics. The optical absorption spectra at room temperature indicated that the absorption band due to the 4A24T1(P) transition of Co2+ ions in tetrahedral sites showed three peaks (520, 586 and 686 nm) for the glass and three peaks (560, 597, and 646 nm) for the glass-ceramics. This difference in the spectra suggests that some Co2+ ions replaced the Ga3+ ions in tetrahedral sites of the LiGa5O8 microcrystals.
  • Rameshwar Dass, Jaswant Ram Mehta
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 999-1001
    Published: 1994
    Released: July 13, 2006
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    3-Hydroxy-2-(4-methoxyphenyl)-6-methyl-4H-chromen-4-one (HL) behaved as a sensitive spectrophotometric reagent for molybdenum(VI). The metal ion formed a yellow complex with the reagent in acetic acid medium. The complex was extractable into 1,2-dichloroethane and the absorbance values remained unchanged for more than one week. Spectral data showed the formation of 1 : 2 species with λmax value at 411 nm. Beer’s law was obeyed over the concentration range of 0—2.3 ppm. The molar absorptivity and Sandell’s sensitivity were calculated to be 5.61 × 104 dm3 mol−1 cm−1 and 0.0017 μg Mo cm−2 respectively, at 411 nm. The effect of as many as 41 cations and 28 anions and complexing agents was studied. Out of these only Sn(II), Ce(IV), citrate, oxalate, disodium dihydrogen ethylenediaminetetraacetate, and hydrogen peroxide interfered seriously. For ten replicate determinations of 1 μg Mo cm−3 the standard deviation was 0.008 with a relative mean error of ±0.09%. The method is simple, selective, precise and rapid. It has been applied satisfactorily to the determination of molybdenum in steels, waters and flue dust samples.
  • Tohru Saitoh, Manabu Okuyama, Tamio Kamidate, Hiroto Watanabe, Kensaku ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1002-1006
    Published: 1994
    Released: July 13, 2006
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    Lanthanoids(III) and yttrium(III) were extracted with N-(2,2-dimethylvaleryl)-N-phenylhydroxylamine (DV-PHA) having a tertiary alkyl group attached to the carbonyl group. The distribution ratio of a lanthanoid(III) ion between the carbon tetrachloride and the aqueous phases was measured as functions of the pH and DV-PHA concentration at 298 K and an ionic strength of 0.1 (NaNO3). The aqueous phase involved sodium tartrate (1.0 × 10−2 mol dm−3). Lanthanoids(III) were extracted as a self-adducted chelate, ML3(HL)3, with DV-PHA (HL). The separation factors for pairs of Yb/Eu and Yb/Y were considerably greater than those of bis(2-ethylhexyl)hydrogenphosphate. The excellent selectivity of DV-PHA was attributable to a greater inductive effect of the tertiary alkyl group than those of the primary and secondary alkyl groups.
  • Chitra Saxena, Ran Vir Singh, Suresh Chand Joshi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1007-1012
    Published: 1994
    Released: July 13, 2006
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    Stereochemical and biochemical aspects of some difluoroboron complexes of the types BF2(NS) and BF2(NO) with ligands having (NS) and (NO) donor systems have been described. Based on IR, 1H NMR, 13C NMR, 19F NMR, and 11B NMR spectral studies, a tetracoordinated state of boron has been established. In order to assess their growth inhibiting potency the ligands and their fluoroboron complexes have been tested in vitro against a number of pathogenic fungi and bacteria at different concentrations and were found to possess remarkable fungicidal and bactericidal properties. The testicular morphology, testicular sperm density, sperm motility, density of cauda epididymal spermatozoa, and fertility in mating trails and biochemical parameters of reproductive organs with 2-acetylthiophene thiosemicarbazone, 2-acetylnaphthalene semicarbazone, and their fluoro complexes in vivo have also been examined and discussed.
  • Takayoshi Suzuki, Mette Rude, Kim P. Simonsen, Mitsuo Morooka, Hitoshi ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1013-1023
    Published: 1994
    Released: July 13, 2006
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    The iridium(III) complexes containing (2-aminoethyl)dimethylphosphine (edmp) or (2-aminoethyl)diphenylphosphine (edpp) were prepared. Crystal structures of fac-[Ir(edmp)3]Cl3·5H2O (2), trans(Cl,Cl),cis(P,P)-[IrCl2(edpp)2]BF4 (3), and Δ(lel3)- and Λ(ob3)-[Ir(R,R-chxn)3](NO3)3·3H2O (4 and 5; chxn = trans-1,2-cyclohexanediamine) were determined by single-crystal X-ray diffraction. Crystal data and final R values are: for 2, FW = 703.7, triclinic, , a = 11.718(2), b = 13.199(1), c = 9.482(1) Å, α = 91.44(1), β = 105.86(1), γ = 90.53(1)°, V = 1410.0(2) Å3, Dx = 1.66 Mg m−3, and Z = 2, R = 0.039 for 5410 reflections. For 3, FW = 808.5, triclinic, , a = 11.465(1), b = 13.694(1), c = 10.049(1) Å, α = 94.764(6), β = 92.197(8), γ = 102.807(8)°, V = 1530.5(2) Å3, Dx = 1.75 Mg m−3, and Z = 2, R = 0.035 for 5978 reflections. For 4, FW = 774.9, hexagonal, P63, a = 13.005(1), c = 10.221(2) Å, V = 1497.1(3) Å3, Dm = 1.71(2), Dx = 1.72 Mg m−3, and Z = 2, R = 0.020 for 1063 reflections. For 5, hexagonal, FW = 774.9, P63, a = 13.359(1), c = 9.848(2) Å, V = 1522.0(3) Å3, Dm = 1.70(2), Dx = 1.69Mg m−3, and Z = 2, R = 0.015 for 1105 reflections. The average Ir–N bond length of 2.167(6) Å in 2 is longer by 0.077(6) Å than those in 4 and 5. The structural data of the corresponding cobalt(III) and rhodium(III) complexes show that the order of the strength of the trans influence of the –PMe2 group in edmp is CoIII < IrIII < RhIII. In 3, the elongation of the metal–nitrogen bond length by the trans influence of the –PPh2 group in edpp is smaller than that of the –PMe2 group in 2, and the elongation is nearly the same as those in the corresponding cobalt(III) and rhodium(III) complexes. The absorption spectra of the two series of complexes, fac-[M(edmp)3]3+ and trans(Cl,Cl),cis(P,P)-[MCl2(edpp)2]+ (M = CoIII, RhIII, and IrIII) are compared and Shimura’s spectrochemical parameters for iridium(III) are discussed.
  • Kunihiro Watanabe, Kazuaki Demura, Kazuo Fueki
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1024-1028
    Published: 1994
    Released: July 13, 2006
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    Capillary-tube isotachophoresis was conducted to determine the average valence of thallium in high-temperature Tl-Ba-Ca-Cu-O superconductor samples. A superconductor sample (5—7 mg) was dissolved in 2.5 ml of 0.3 M (M = mol dm−3) HCl. The solution was diluted to 25 ml with distilled water. By injection of a 50 μl sample solution into the analyzer, thallium(I) was determined at 0.05—5 μg with a relative standard deviation of 3.3%. Hydrochloric acid (5.0 × 10−3 M) and LiCl (1.0 × 10−2 M) were selected as leading and terminating electrolytes, respectively. The order of the mobility of the metal ions was Tl+ > Ba2+ > Ca2+ > Cu2+. Thallium(III) ion was not detected as a zone. The total of thallium was determined after the reduction of Tl3+ to Tl+ with ascorbic acid. The average valence values of thallium in the superconductors were 2.93—2.97. The interference of the Tl3+ ion in the determination of the average valence of copper was examined. When the valence of copper was determined with KI by extraction-spectrometry, the Tl3+ ion was found to affect the absorbance of the ion-pair complex extracted into chloroform. The effect of this ion was eliminated by a suitable selection of the wavelength.
  • Makoto Sakurai, Makoto Watanabe
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1029-1032
    Published: 1994
    Released: July 13, 2006
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    Hydrated tetrasodium tetra-μ-imido-cyclo-tetraphosphate, (NaPO2NH)4·2.5H2O, has been prepared by hydrolyzing 2,2,4,4,6,6,8,8-octachloro-2λ5,4λ5,6λ5,8λ5-cyclotetraphosphaza-1,3,5,7-tetraene in an aqueous sodium acetate solution. The tetra-μ-imino-cyclo-tetraphosphate reorganized to produce trisodium tri-μ-imido-cyclo-triphosphate and then changed to make chain and ring condensed phosphates containing imino groups upon heating above 180 °C in air according to the following reactions:

    All kinds of the imidopolyphosphates were finally converted to sodium cyclo-triphosphate above 550 °C by the substitution of imino groups for bridging oxygens and reorganization of the thermal products.
  • Nobuyoshi Shinohara, Makoto Iwasawa, Takashi Akiyama
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1033-1040
    Published: 1994
    Released: July 13, 2006
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    The chain decomposition of the bis(oxalato)peroxotitanate(IV) complex [Ti(O2)(ox)2]2− (ox = C2O42−) is initiated by the addition of a very small amount of reducing agent, such as Ti(III), Cr(II) or V(II). The chain length increases with increasing the concentrations of added [TiO(ox)2]2− and oxalate ion; the maximum chain length was 600 under the experimental conditions. The decomposition reaction gave 2 mol of CO2 per 1 mol of decomposed [Ti(O2)(ox)2]2−. Ti(III), Cr(II), and V(II) reductions of [Ti(O2)(ox)2]2− produced ·OH, identified by the spin-trapping technique using a 5,5-dimethyl-1-pyrroline-N-oxide radical trap. Oxygen is an inhibitor of the chain reaction in this system. The chain-decomposition mechanism is discussed.
  • Toru Ozeki, Yoshihiro Kinoshita, Hirohiko Adachi, Shigero Ikeda
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1041-1047
    Published: 1994
    Released: July 13, 2006
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    The dissolved structures of mono- and dinuclear chromate species, CrO42−, HCrO4, H2CrO4, and Cr2O72− in aqueous solution were estimated by optimizing their structure models so that UV-vis absorption spectra reproduced from molecular orbital calculation DV-Xα fitted to the experimentally obtained component spectra. It is demonstrated that bond order obtained by Mulliken’s population analysis gives useful information to explain why dimerization reaction of HCrO4 to form Cr2O72− proceeds easily.
  • Sen-ichi Aizawa, Shigenobu Funahashi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1048-1053
    Published: 1994
    Released: July 13, 2006
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    The dissociation rates of the sodium(I) cryptates of 4,7,13,16,21-pentaoxa-1,10-diazabicyclo[8.8.5]tricosane (C221) and 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (C222) in ethylenediamine have been measured at various temperatures and pressures by the 23Na NMR line-broadening method. The dissociation rate constant at 298 K (kd298), activation enthalpy (ΔH), activation entropy (ΔS), and activation volume (ΔV) are as follows: kd298 = 7.2 s−1, ΔH = 45.9 ± 1.8 kJ mol−1, and ΔS = −74.5 ± 5.4 J mol−1 K−1 for Na+C221, and kd298 = 272 s−1, ΔH = 43.2 ± 1.1 kJ mol−1, ΔS = −53.6 ± 3.7 J mol−1 K−1, and ΔV = 8.9 ± 0.4 cm3 mol−1 for Na+C222. The large positive value of ΔV for Na+C222 indicates the dissociative transition state accompanied by the expansion of the cavity of C222. The electrostatic interaction of the sodium cation with ethylenediamine in the transition state has been discussed in connection with the other solvents by comparison of the values of ΔH.
  • Wei-hsien Wang, Ching-chih Cheng
    1994 Volume 67 Issue 4 Pages 1054-1057
    Published: 1994
    Released: July 13, 2006
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    The kinetics of general base catalyzed proton exchange in N,N′-dimethylurea and a series of secondary amides were studied. Kinetic data were determined by NMR line-shape analysis. A good linear correlation was observed for nine amides by plotting log kOH for RCONHCH3 vs. pKa of RCOOH. For amides with N–H more acidic than water (pKa < 15.7), general base catalysis is observed, the Brønsted β is unity, and the reaction with hydroxide is diffusion-controlled. It is concluded that general base catalysis is inoperative in proteins or polypeptides.
  • Shoichiro Ozaki, Yasuji Koga, Lei Ling, Yutaka Watanabe, Yuichi Kimura ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1058-1063
    Published: 1994
    Released: July 13, 2006
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    Some biologically interesting inositol poly(phosphate) derivatives, 2-O-(p-aminobenzoyl)-myo-inositol 1,3,4,5-tetrakis(phosphate), 2-O-(4-aminocyclohexylcarbonyl)-myo-inositol 1,3,4,5-tetrakis(phosphate), myo-inositol 1,3,4,5,6-pentakis(phosphate), and its 2-substituted analogs, were synthesized. Inositol tetrakis(phosphate) and pentakis(phosphate) affinity columns were also prepared. The inositol 1,3,4,5-tetrakis(phosphate) affinity column was found to be effetive in isolating the binding proteins from bovine cardiac membranes.
  • Michio Kondo, Kouji Okamoto, Ichiro Nishi, Makoto Yamamoto, Masood Jel ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1064-1068
    Published: 1994
    Released: July 13, 2006
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    NMR spectroscopy is a versatile method for the conformational analysis of peptides and proteins. The hydrogen–chlorine exchange of amide NH protons is detected by 1H NMR and used as a method to distinguish between intramolecularly hydrogen-bonded and solvent-exposed NH moieties. The method has been applied to hydrogen bond detection in naturally occurring antibiotic peptides, such as gramicidin S, and CH3CONH–X (X = alkyl- or aryl-) derivatives. The deuterium exchange method was compared with this method in parallel experiments. In the case of chlorine exchange, in contrast to deuterium exchange, the hydrogen-bonded amide protons are replaced much faster than their solvent-exposed counterparts and the duration of the experiments is considerably less. It is highly possible that the hydrogen–chlorine exchange reaction under the present experimental conditions, in the dark and at room temperature, proceeds through an electrophilic polar mechanism.
  • N. Sukumar, M. N. Ponnuswamy, J. C. Thenmozhiyal, R. Jeyaraman
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1069-1073
    Published: 1994
    Released: July 13, 2006
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    The structures of the title compounds, 2,6-di-2-furyl-3,5-dimethyl-4-piperidinone (DFMP) and its N-nitroso derivative (DFMPNO), have been investigated in solution and the solid state by NMR and X-ray methods, respectively. Both of the structures were solved by direct methods of X-ray analysis and were refined to an R-factor of 0.059 and 0.057, respectively. The piperidine ring adopts a chair conformation in DFMP and a boat conformation in DFMPNO. Both of the furan rings are in an equatorial orientation in DFMP, whereas in DFMPNO one ring is in the axial position and the other ring is in the equatorial position. The nitroso group is in the perpendicular orientation in DFMPNO. The angle between the best plane of the piperidine ring and the nitroso group is 142.1(4)°. The interaction between the molecules are van der Waals in nature in both structures.
  • Toshiyuki Urano, Kim-Oanh Nguyen, Hideki Nagasaka, Masaaki Tsuchiyama, ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1074-1077
    Published: 1994
    Released: July 13, 2006
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    Sensitization mechanisms of two systems of (dialkylamino)styryl-type dyes with a radical-generating reagent, 2-[p-(diethylamino)styryl]-, and 2-[2-(9-julolidinyl)vinyl]naphtho[1,2-d]thiazole with 3,3′,4,4′-tetrakis(t-butyldioxycarbonyl)benzophenone, in poly(methyl methacrylate) film have been investigated by laser flash photolysis using a total reflection cell.
  • Kensaku Morihara, Michie Takiguchi, Toyoshi Shimada
    1994 Volume 67 Issue 4 Pages 1078-1084
    Published: 1994
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    Chiral amines, (R)- and (S)-N-benzyl-α-methylbenzylamine, served as templates in a molecular imprinting we developed. They formed “molecular footprint” cavities on a silica (alumina) gel surface, which showed catalytic activities toward transacylation of benzoic anhydride. The catalyses were susceptible to enantioselective inhibitions by the rebinding of the chiral template amines. This finding proved that the cavities could show chiral recognition through their chirally marked cavity structures.
  • Masahiro Kohno, Yukio Mizuta, Masako Kusai, Toshiki Masumizu, Keisuke ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1085-1090
    Published: 1994
    Released: July 13, 2006
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    A quantitative analysis of superoxide anion radical (·O2) and hydroperoxyl radical (·OOH) generated in the hypoxanthine–xanthine oxidase (HPX–XOD) reaction system in the presence of dimethyl sulfoxide (DMSO) was explored by a spin-trapping method using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) combined with electron spin resonance spectroscopy (ESR). ·O2 and/or ·OOH was detected by ESR spectra of the spin adduct, DMPO–O2 (or DMPO–OOH). The concentration of DMPO–O2 was increased up to three times by the addition of DMSO. The half-life of DMPO–O2, which is the time period to reduce to one-half of the initial intensity, also became about 70 times longer than that in the system without DMSO. These results suggest that the short half-life of DMPO–O2 that has been reported is attributable to the partial reaction of hydroxyl radical (·OH) with DMPO–O2. Consequently quantitative analysis of ·O2 was possible in the presence of DMSO (>0.35 M). Under these conditions, kinetic approaches show that the generation of ·O2 in the HPX-XOD reaction is a first-order reaction and that its rate constant is 6.9 × 10−8 M s−1. Finally, the competitive reaction of DMPO and SOD toward ·O2 was shown to be one unit of superoxide dismutase (Cu/Zn– SOD) scavenging ·O2 by the rate constant of 7.0 × 10−6 M min−1. This method, which can be used for measurement of SOD-like and SOD-minic activity, should be called the superoxide anion scavenging activity method.
  • Jitender Mohan Khurana, Abhijit Ray, Prabhat Kumar Sahoo
    1994 Volume 67 Issue 4 Pages 1091-1093
    Published: 1994
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    A simple and convenient procedure for the deoximation with 0.5 M aqueous hypochlorite at ambient temperature is reported. Ketoximes yielded ketones quantitatively and aldoximes yielded aldehydes only at pH 5—7 or mixture of aldehydes and carboxylic acids at pH 10—11.
  • Akira Mori, Kanji Kubo, Hitoshi Takeshita
    1994 Volume 67 Issue 4 Pages 1094-1099
    Published: 1994
    Released: July 13, 2006
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    5,8,11,14,17-Pentaoxa-2,20-dithiabicylco[19.4.1]hexacosa-21,23,25-trien-26-one and its homologues gave, via remote substitution, 8,8-dicyanoheptafulvene-incorporated dithio-crown-ether derivatives upon heating with malononitrile in acetic anhydride. This means that 7-acetoxy-7-dicyanomethyl-1,3,5-cycloheptatrienes, ipso-attacked intermediates of malononitrile to acetoxytropylium derivatives, were not formed on a steric ground. These dithio-crown-ethers efficiently extract and reversibly transport mercury(II) ion.
  • Suketaka Ito, Akikazu Kakehi, Keiichi Tabata
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1100-1106
    Published: 1994
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    Thermolysis of aryl azidometyl ketone N-methyl-N-phenylsulfonylhydrazones gave aryl 4-aryl-2-imidazolyl ketone N-methyl-N-phenylsulfonylhydrazones and arylglyoxal bis(N-methyl-N-phenylsulfonylhydrazone)s, the formation of which can be interpreted in terms of the insertion of nitrene into the α-methylene C–H bond of the original azidomethyl ketone hydrazones and the formation of an azo intermediate from the nitrene precursor, respectively. The sturctures of these products have been confirmed by an X-ray diffraction method.
  • Kyoko Takahashi, Makoto Shibagaki, Hideyuki Kuno, Hajime Matsushita
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1107-1112
    Published: 1994
    Released: July 13, 2006
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    The reduction with 2-propanol as a hydrogen source over hydrous tin(IV) oxide has proved to be successful. Hydrous tin(IV) oxide was prepared from stannic(IV) chloride by precipitation with aqueous ammonia, followed by drying and calcination at 300 °C for 5 h. The specific surface area was 150 m2 g−1. The reductions were carried out in the vapor phase at temperatures of from 300 to 330 °C. The reduction of aliphatic carboxylic acids gives the corresponding alcohols. Aromatic carboxylic acids and their derivatives were further reduced, and the corresponding hydrocarbons were obtained. The reductions of aromatic ketones and the derivatives of benzyl alcohol also gave hydrocarbons. In the reaction of alkyl halides, reductive dehalogenation proceeded and the corresponding hydrocarbon was produced.
  • Shuntaro Mataka, Guo-Bin Liu, Tsuyoshi Sawada, Masayoshi Kurisu, Masas ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1113-1119
    Published: 1994
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    Tri- and dibromination of methyl-, dimethyl-, and trimethylbenzenes with N-bromosuccinimide were accomplished by photothermal reaction with a tungsten lamp in carbon tetrachloride or benzene. (Dibromomethyl)arenes and (tribromomethyl) derivatives were produced depending upon a solvent used and a substituent on the benzene ring. In the bromination of methylbenzenes without a substituent on the ortho-position, (tribromomethyl)benzenes were formed. On the other hand, ortho-substituted methylbenzenes gave (dibromomethyl)benzenes. α,β-Dibromo-1,2-diarylstilbenes were formed via the debrominative carbon–carbon coupling reaction of (tribromomethyl) benzenes upon irradiation with a tungsten lamp.
  • Hiromi Sakai, Shinji Takeoka, Yuriko Seino, Eishun Tsuchida
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1120-1125
    Published: 1994
    Released: July 13, 2006
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    The suppression of methemoglobin (metHb) formation by glutathione (GSH) is difficult because GSH is oxidized not only by the reduction of metHb, but also by oxygen to generate active oxygen species, such as superoxide (O2−•) and hydrogen peroxide (H2O2), which contribute to metHb formation. An effective nonenzymatic reduction of metHb was achieved at a high concentration of Hb (40 wt%, 2.48 × 10−2 M subunits (1 M = 1 mol dm−3)) because the reduction of metHb was accelerated, and at a low partial pressure of oxygen (pO2 = 40 Torr (1 Torr = 133.322 Pa)) because the oxidation of GSH was effectively suppressed. Hb-vesicles, which encapsulate concentrated Hb (40 wt%, 2.48 × 10−2 M subunits), transport oxygen in the blood stream at relatively low pO2 (110 Torr in artery and 40 Torr in venous, 58 Torr in average). The rate of metHb formation in Hb-vesicles was effectively decreased from 3.8 × 10−7 to 1.6 × 10−7 M s−1 by coencapsulating GSH at 58 Torr.
  • Shuki Araki, Masafumi Yamada, Yasuo Butsugan
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1126-1129
    Published: 1994
    Released: July 13, 2006
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    The organoindium reagent, derived from indium metal and bromoacetonitrile, reacted with carbonyl compounds in the presence of chlorotrimethylsilane to give, after hydrolysis, β-hydroxy nitriles. The coupling proceeded with high chemoselectivity, though the diastereoselectivity was low.
  • Eisuke Kaji, Yumiko Osa, Keiko Takahashi, Motoko Hirooka, Shonosuke Ze ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1130-1140
    Published: 1994
    Released: July 13, 2006
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    The title β-D-ManNAcA-donor, the α-bromide of methyl 2-benzoyloxyimino-2-deoxy-D-arabino-hexopyranuronate 9, has been prepared from D-glucuronolactone in an overall yield of 21% for the seven steps required, all intermediates being securable in crystalline form. Key compounds were the 2-acetoxy-D-glucuronal ester 6 and its hydroxylaminolysis product, the 1,5-anhydro-D-fructuronate oxime 7, the latter elaborating 9 on O-benzoylation (→8) and photobromination. —The utility of 9 as a suitable β-D-ManNAcA donor rests on two ensuing reactions: first, Koenigs-Knorr type glycosidations, with N-blocked 2-aminoethanols as spacer substrates, or with the 6-OH of an otherwise protected glucoside (16), produce β-selectivities of 20 : 1 or better, and second, the oxime reduction of the β-glycosides, thus obtained, proceeds in an essentially stereospecific manner to yield, upon N-acetylation, the 2-acetamido-2-deoxy-β-D-mannosiduronates. —The methodology elaborated was used to prepare some novel artificial glycolipids, e.g. the (myristoylamino)ethyl 6-O-(2-acetamido-2-deoxy-β-D-mannopyranosyluronic acid)-α-D-glucopyranoside (25) and its (stearoylamino)ethyl analog (26), that are being evaluated as recognition markers for liposomes.
  • Morio Asaoka, Katsuhiro Kobayashi, Hisashi Takei
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1141-1146
    Published: 1994
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    Starting from optically active 5-trimethylsilyl-2-cyclohexen-1-one derivatives, the title dienes were synthesized by using silicon-mediated 1,4-elimination as a key step. A straightforward synthesis of the unnatural enantiomer of (−)-dictyopterene C′ utilizing the method was also carried out.
  • Miwa Hirai, Kazuo Shinozuka, Hiroaki Sawai, Shojiro Ogawa
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1147-1155
    Published: 1994
    Released: July 13, 2006
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    A copper complex of a macrocylcic compound consisting of two 1,10-phenanthroline molecules bridged by two sulfur atoms, [Cu(smc)], was synthesized. The interaction of [Cu(smc)] with DNA was examined by UV-vis absorption spectroscopy, circular dichroism spectroscopy, and viscometry. The binding constant of [CuI(smc)] with DNA is 4.2 × 104 M−1, which is almost identical with that of bis(1,10-phenanthroline)copper, [CuI(phen)2]. A viscosity measurement indicates that [CuI(smc)] binds to DNA by an intercalative mode. [Cu(smc)] cleaves DNA in the presence of a reducing agent under an aerobic condition. In this process ·OH plays an important role.
  • Koichi Narasaka, Hidehiro Sakurai, Changqing Liu
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1156-1160
    Published: 1994
    Released: July 13, 2006
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    Reactions of tricarbonyl(η6-triisopropylsilyl(TIPS)benzene)chromium(0) complex 1b with various alkyllithiums proceed regioselectively, giving para-substituted TIPSbenzenes in high yield after oxidation with iodine. Vinyllithiums also react with the TIPSbenzenechromium complex to give para-TIPSstyrenes in good yield. In the reaction with phenyllithium, although the para-substituted product is obtained as a main product, deprotonation of the aryl group of the chromium complex also occurs competitively to afford bisTIPSbiphenyls as a by-product. Alkynyllithium, however, attacks the TIPS group to yield alkynylsilane and TIPSbiphenyl.
  • Mark V. Sigalov, Shinji Toyota, Michinori Oki, Boris A. Trofimov
    1994 Volume 67 Issue 4 Pages 1161-1169
    Published: 1994
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    Topomerization observed for the isopropyl-methyls in the title compounds was reinvestigated with use of the total line shape analysis of NMR spectra. It was found that deprotonation from the pyrrolium cation preceded and was an independent step from the topomerization but the former strongly affects kinetic parameters for the latter process in the presence of excessive hydrogen halide. The extent of the excessiveness of hydrogen halide in the system also affects the reaction rates and the effects were discussed on the standpoint of activation parameters. The rates of topomerization of the isopropyl-methyls were found to be identical with the rates of enantiomerization at the 1-substituent in 1-(1-bromopropyl)-3-isopropyl-2-phenylpyrrolium ion to suggest that the topomerization in other compounds was also attributed to the ionization at the 1-substituent. The results suggest that a 1-pyrrolyl group assists ionization of 1-pyrrolylmethyl halide more effectively than a phenyl group in benzyl halide. This was reproduced by ab initio calculations.
  • Jun-ichi Tateiwa, Ikuo Aoki, Masakazu Suama, Sakae Uemura
    1994 Volume 67 Issue 4 Pages 1170-1177
    Published: 1994
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    Friedel–Crafts transannular alkylation of aromatic compounds with nonconjugated cyclic dienes such as (Z,Z)-1,5-cyclooctadiene (1,5-COD), bicyclo[2.2.1]hepta-2,5-diene (norbornadiene), and 1,4-cyclohexadiene was studied. The five to six isomers of phenylbicyclooctanes were produced in the alkylation of benzene with 1,5-COD in the presence of either Brönsted acid or Lewis acid as the catalyst. The isomer ratios depended on the nature and the amount of catalyst, the reaction time, and the reaction temperature. In the AlCl3-catalyzed reaction of 1,5-COD with toluene it was disclosed that an initial para-rich isomer distribution of the products shifted to a meta-rich one in a prolonged reaction. With norbornadiene a transannular cyclized compounds was obtained, while with 1,4-cyclohexadiene no transannular cyclization was observed.
  • Hiroyuki Saimoto, Jiro Ueda, Hitoshi Sashiwa, Yoshihiro Shigemasa, Tam ...
    1994 Volume 67 Issue 4 Pages 1178-1185
    Published: 1994
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    A general approach is established for the synthesis of phenolic compounds having terpenoid side chains: (1) protection of the phenolic hydroxyls in the aromatic precursor by ether formation, (2) coupling the aromatic part with a terpenoid bromide, and (3) deprotection to regenerate the hydroxyl groups. This strategy was successfully applied to the synthesis of colletochlorins B and D and grifolin. Some of the colletochlorin derivatives were found to inhibit the cell growth of P388.
  • Toshio Okuhara, Changwen Hu, Masato Hashimoto, Makoto Misono
    1994 Volume 67 Issue 4 Pages 1186-1188
    Published: 1994
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    UV spectrophotometry of a Hammett indicator revealed that the acid strength of the Keggin-type heteropolyacids having W as addenda atoms increased as the valency of the central atom increased (Co < B < Si, Ge < P). The catalytic activity for the decomposition of isobutyl propionate in a homogeneous system was correlated well with the acid strength.
  • Haruo Sekizaki, Chisako Chinen, Eiko Toyota, Yoshihisa Yamamoto
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1189-1192
    Published: 1994
    Released: July 13, 2006
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    The cis-α, cis-β1, and cis-β2-isomers of (2-oxidephenylacetato)(triethylenetetramine)cobalt(III) chloride hydrate, [Co(opa)(trien)]Cl·nH2O (opa = 2–oxidephenylacetato, trien = triethylenetetramine), have been prepared and characterized by means of analytical and spectroscopic methods. The cis-α and cis-β1-isomers of this complex were more stable than those of the salicylato- or thiosalicylato(triethylenetetramine)cobalt(III) complexes in basic aqueous solution.
  • Tadashi Hara, Hisashi Nishida, Syuji Kayama, Riichiro Nakajima
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1193-1195
    Published: 1994
    Released: July 13, 2006
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    To improve the sensitivity of on-line chemiluminescence dectection of proteins separated by capillary zone electrophoresis, rhodamine B isothiocyanate has been used as a dye-stuff for labeling proteins. By the present method, bovine serum albumin (BSA) in the concentration range of 7 × 10−8—7 × 10−6 M (1 M = 1 mol dm−3) could be determined with a lower detection limit of 5 × 10−8 M (absolute amounts : 1 fmol).
  • Hironao Takada, Seiji Takagi, Hiromu Kawakubo
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1196-1197
    Published: 1994
    Released: July 13, 2006
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    The Pseudomonas cepacia lipase-catalyzed enantioselective hydrolysis of trans-2-(t-butoxycarbonyl)-aminocyclohexyl acetate was readily accomplished to provide a practical method for the industrial preparation of enantiomerically pure (1R,2R)- and (1S,2S)-2-aminocyclohexanols.
  • Nagashige Kimbara, Shunsuke Izumi, Toshifumi Hirata
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1198-1200
    Published: 1994
    Released: July 13, 2006
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    Disulfite was found to be an excellent oxidizing reagent for a gentle and stereoselective reaction to produce trans-diols via corresponding epoxides from the cyclohexenes, such as 1-p-menthen-8-yl acetate, 1,8-p-menthadiene, and 2-pinene.
  • Kenichi Nakabayashi, Kyouko Ohashi, Setsuo Takamuku
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 4 Pages 1201-1203
    Published: 1994
    Released: July 13, 2006
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    The photochemical cistrans isomerization and cycloaddition of methyl trans-3-arylpropenoates in benzene via triplet state were investigated. The results of triplet sensitized cistrans isomerization clearly indicated that the most stable conformation for methyl 3-phenylpropenoate is a twisted form while methyl 3-(4-biphenylyl)propenoate and methyl 3-(2-naphthyl)propenoate are in the equilibrium states between the trans-planar triplet and twisted form. Photoirradiation of these methyl 3-arylpropenoates in relatively high concentrated benzene solutions gave two isomeric cyclodimers of dimethyl t-3, t-4-diaryl-r-1, c-2-cyclobutanedicarboxylate and dimethyl c-3, t-4-diaryl-r-1, t-2-cyclobutanedicarboxylate as main products. The reactivities of cycloaddition are relatively high where the most stable conformation is twisted form.
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