Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 68 , Issue 3
Showing 1-50 articles out of 52 articles from the selected issue
  • Naohiko Mikami
    1995 Volume 68 Issue 3 Pages 683-695
    Published: 1995
    Released: July 05, 2006
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    Spectroscopic studies of the hydrogen-bonding clusters of phenol were reviewed with an emphasis of the characterization of the cluster structures involving the proton transfer processes. Two experimental methods which were newly developed for the spectroscopy of the size selected clusters and their ions were described. Trapped ion photodissociation spectroscopy revealed that chromophore alternation occurs in the cluster cations with various proton-accepting molecules, such as NH3 and H2O. The infrared spectroscopy combined with the ionization detection was applied to the spectra of the OH vibrations which characterized the neutral clusters of phenol with water. The spectroscopic evidence of the ion-pair form of the neutral cluster is presented and the possibility of the intracluster acid-base reaction is discussed.
  • Keitaro Yoshihara, Keisuke Tominaga, Yutaka Nagasawa
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 696-712
    Published: 1995
    Released: July 05, 2006
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    Recent theoretical and experimental progress concerning electron transfer (ET) in solution is reviewed by focusing on the mechanism of ET, which occurs much faster than solvation dynamics. Theories of ET in solution are briefly reviewed with particular emphasis placed on the relation to solvent dynamics. Experimental methods to investigate solvent polarization relaxation are described. Ultrafast intramolecular ET, which is found in back ET from the photo-induced charge-transfer state to the ground state, is described concerning highly polar betaines and mixed-valence compounds. Ultrafast intermolecular ET has been observed for the systems of various dyes in electron-donating solvents. A non-exponential process with a significant temperature dependence was observed in aniline. A faster ET with a single exponential decay as fast as 1013 s−1 was observed with no temperature dependence in a system of oxazine 1 in N,N-dimethylaniline. The ET rate constants of excited coumarins in electron-donating solvents drastically depend on the substituent groups of the coumarin. Relatively small Stokes shifts in steady-state fluorescence spectra of ultrafast reacting molecules in solution are evidence of a “chemical timing” effect; namely, the reaction occurs in a non-equilibrium configuration of the solvent. These experimental observations are explained in terms of the extended Sumi–Marcus theory, in which the effect of solvation dynamics and low- and high-frequency vibrational modes are taken into account.
  • Yasuhiro Uozumi, Kenji Kitayama, Tamio Hayashi, Kazunori Yanagi, Emiko ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 713-722
    Published: 1995
    Released: July 05, 2006
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    Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 °C in the presence of 1 × 10−3 or 1 × 10−4 molar amounts of palladium catalyst prepared in situ from [PdCl(η3-C3H5)]2 and (S)-2-diphenylphosphino-2′-methoxy-1,1′-binaphthyl ((S)-MeO-MOP) proceeded with unusual regioselectivity and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes together with a minor amount of 1-(trichlorosilyl)alkanes. Optically active alcohols, RCH(OH)CH3, were obtained by oxidation of the carbon–silicon bond. Regioselectivities for forming 2-silylalkanes over 1-silylalkanes and enantiomeric purities of alcohols are as follows: R = n-C4H9: 89/11, 94% ee (R). R = n-C6H13: 93/7 95% ee (R). R = n-C10H21: 94/6, 95% ee (R). R = PhCH2CH2: 81/19, 97% ee (S). R = PhCH2CH2CH2: 80/20, 92% ee (R). R = cyclo-C6H11: 66/34, 96% ee (R). A similar hydrosilylation of 1-alkenes, 4-pentenyl benzoate and 1,5-heptadiene gave corresponding 2-alkanols of 90% ee and 87% ee, respectively, the ester carbonyl and the internal double bond remaining intact.
  • Yasuo Miki, Yoshikazu Sugimoto
    1995 Volume 68 Issue 3 Pages 723-729
    Published: 1995
    Released: July 05, 2006
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    The selectivity of ring opening was investigated for the hydrocracking of acenaphthene under an initial hydrogen pressure of 6 MPa and in the temperature range from 390 to 450 °C. Major products were classified into the following six components: tetrahydroacenaphthylene, hexahydroacenaphthylene, perhydroacenaphthylene, ring opening products (bicyclic compounds and monocyclic compounds), alkylation products (tricyclic compounds of C13 or larger), and dimerization products (biacenaphthene and their hydrogenated compounds). Ring opening of acenaphthene proceeded via two routes: the direct ring opening of acenaphthene and ring opening after hydrogenation to hexahydroacenaphthylene. In the former reaction only 1-ethylnaphthalene was produced, while 1,8-dimethylnaphthalene and its hydrogenated products were not observed. In the latter reaction, on the other hand, two types of ring opening of a C–C bond adjacent to the benzene ring, the opening of a saturated five-membered ring to produce 1-ethyltetralin and the opening of a saturated six-membered ring to produce 1-propylindane, were observed.
  • Naader Alizadeh, Hossein Gharibi, Mojtaba Shamsipur
    1995 Volume 68 Issue 3 Pages 730-733
    Published: 1995
    Released: July 05, 2006
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    A membrane electrode selective to hexadecylpyridinum bromide was used to study the micellization of the surfactant in various methanol–water mixtures at 25 °C. There is a linear relationship between log cmc and the weight percent of methanol in solvent mixtures. The degree of counter-ion dissociation at different solvent compositions is reported. The degree of methanol attachment was found to be 2.04. The charged phase-separation model was used to express the mechanism of the mixed micelle formation.
  • Bijan Das, Dilip K. Hazra
    1995 Volume 68 Issue 3 Pages 734-737
    Published: 1995
    Released: July 05, 2006
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    The apparent and partial molar volumes (φv) of six symmetrical tetraalkylammonium perchlorates (Me4NClO4 to Hex4NClO4) have been determined in 2-methoxyethanol at 25, 35, and 45 °C. The apparent molar volumes were extrapolated to zero concentration to obtain limiting values at infinite dilution. Ionic limiting partial molar volumes have been estimated using the extrapolation method. The analysis of the data shows that the tetraalkylammonium ions are scarcely solvated and that strong ion–ion interaction exists between the oppositely charged ions in this medium. The temperature dependence of the limiting partial molar volumes have been explained on the basis of ion–solvent interactions.
  • Sadamu Yoshida, Kozo Kozawa, Tokiko Uchida
    1995 Volume 68 Issue 3 Pages 738-743
    Published: 1995
    Released: July 05, 2006
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    Photovoltaic behaviors of evaporated thin films of triphenodioxazine (TPDO) and 6,13-dichlorotriphenodioxazine (DClTPDO) were investigated with sandwich-type cells, the configurations of which were Ag/TPDO/Al and Al/DClTPDO/indium–tin oxide (ITO). The action spectra of the short-circuit photocurrent suggest that only the photons absorbed by pigments near the Ag/TPDO interface or the DClTPDO/ITO interface are effective to produce carriers for external circuits. These results mean that Schottky barriers are formed at these interfaces, and that both pigment layers act as n-type semiconductors. Observed effects of oxygen and/or hydrogen gas on the dark conductivity of these pigment films also reflect the n-type semiconducting behavior. The observed electrical behaviors are consistent with the proposed band structures for these two cells, which are estimated from the spectroscopic data.
  • Masanori Yasui, Shin Murata, Fujiko Iwasaki, Naomichi Furukawa
    1995 Volume 68 Issue 3 Pages 744-751
    Published: 1995
    Released: July 05, 2006
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    The crystal structures of 1-phenylsulfinyl-9-phenylthiodibenzothiophene (1), 1,9-bis(phenylthio)dibenzothiophene (2), 1,9-bis(phenylthio)dibenzoselenophene (3), and 1,9-bis(phenylseleno)dibenzoselenophene (4) have been determined by an X-ray method in order to investigate the existence of a short intramolecular S···S or Se···Se contact. The crystal data are: 1, C24H16OS3, Mw = 416.59, Monoclinic, P21/n, a = 9.980(4), b = 8.843(4), c = 21.933(9) Å, β = 92.20(4)°, V = 1934(1) Å3, Z = 4, R = 0.028, wR = 0.027 for 2899 observed reflections. 2, C24H16S3, Mw = 400.59, Monoclinic, P21/n, a = 17.862(2), b = 8.050(2), c = 13.549(2) Å, β = 95.74(1)°, V = 1938.4(5) Å3, Z = 4, R = 0.053, wR = 0.075 for 3251 refined reflections (R = 0.057 for 3256 observed reflections). 3, C24H16S2Se, Mw = 447.48, Monoclinic, P21/n, a = 17.899(4), b = 8.086(2), c = 13.631(2) Å, β = 96.33(2)°, V = 1960.8(7) Å3, Z = 4, R = 0.046, wR = 0.070 for 2818 refined reflections (R = 0.050 for 2822 observed reflections). 4, C24H16Se3, Mw = 541.27, Monoclinic, P21/n, a = 18.094(2), b = 8.1571(6), c = 13.723(1) Å, β = 96.51(1)°, V = 2012.4(3) Å3, Z = 4, R = 0.066, wR = 0.066 for 3095 refined reflections (R = 0.067 for 3096 observed reflections). The nonbonding distances between two S atoms of phenylthio groups are 3.016(1), 3.012(1), and 2.973(1) Å for 1, 2, and 3, respectively. The distance of Se···Se of 4 is 3.070(1) Å. These distances correspond to 82.0, 81.8, 80.8, and 76.8% of the sum of the van der Waals radii for 1, 2, 3, and 4, respectively. Dibenzothiophene frameworks show severe deformation based on the steric effect of the 1,9-disubstituents. The dihedral angles between the benzene rings and the thiophene/selenophene rings are 6.6—8.5°. Two S/Se atoms of the phenylthio/seleno groups deviate from the thiophene/selenophene ring by about 1 Å on the opposite sides from each other.
  • Shozo Yanagida, Tomoyuki Ogata, Akihiro Shindo, Hiroji Hosokawa, Hirot ...
    1995 Volume 68 Issue 3 Pages 752-758
    Published: 1995
    Released: July 05, 2006
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    Size-controlled CdS nanocrystallites were prepared by using thiophenol or hexanethiol as a capping reagent by controlling the ratio of Cd2+ to bis(trimethylsilyl) sulfide (S(TMS)2) as a source of the sulfide ion in reversed micelles. Their solubility and photocatalysis were examined. A series of size-controlled phenyl-capped CdS nanocrystallites catalyze the photoreduction of aromatic ketones in the presence of triethylamine as an electron donor under visible-light irradiation. The photocatalytic activity is affected by the particle size, i.e., the reducing power of the photogenerated electron on CdS nanocrystallites toward the ketones increases with decreasing the particle size. The enhancement of photocatalytic activity observed by reducing the particle size should be ascribed to not only a negative shift of the conduction band edge, but also suppression of the formation of surface defects.
  • Mitsutoshi Okano, Tsuyoshi Kugita, Daijiro Ohtani, Hiroshi Hamano
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 759-763
    Published: 1995
    Released: July 05, 2006
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    The 13C and 1H NMR spectra of the triphenylmethyl anion, which had been generated by an electrochemical reduction of triphenylmethane in dimethylformamide at −40 °C, were successfully obtained. An anion having a tetrabutylammonium counter cation had 13C chemical shifts similar to those for an anion with a lithium counter cation. An examination of the 1H NMR spectra revealed that the reaction is a one-electron reaction. Experiments conducted under temperature control showed that the anion is fairly stable below −20 °C. Decomposition of the anion above −20 °C was suggested to be hydrogen abstraction from the β-position of a tetrabutylammonium cation by a triphenylmethyl anion (Hofmann decomposition of the ammonium cation).
  • Toshiyuki Takayanagi
    1995 Volume 68 Issue 3 Pages 764-770
    Published: 1995
    Released: July 05, 2006
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    The laser-induced reaction, K + NaCl + → KCl + Na*, has been studied quantum-mechanically, with consideration of only collinear geometries. Laser-dressed equations are numerically solved by the R-matrix propagation method. Quantum reaction probabilities are dominated by many resonances corresponding to the vibrational states of the reaction complex formed in the reaction. The results obtained are compared with surface hopping trajectory calculations. The trajectory surface hopping model fails in predicting the translational energy dependence of the reaction probabilities but a Landau–Zener model is qualitatively correct in the calculation of the laser wavelength dependence of the reaction probabilities. These results suggest that the dynamics of the laser-induced reaction can be divided into two independent processes; the ground state reaction K + NaCl → KCl + Na and the non-adiabatic transition from the laser-dressed ground state to the excited state.
  • Dock-Chil Che, Tetsuya Ogawa, Hiroshi Ohoyama, Toshio Kasai, Keiji Kuw ...
    1995 Volume 68 Issue 3 Pages 771-774
    Published: 1995
    Released: July 05, 2006
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    The |JKM > state selection of a seeded CH3I/Ar supersonic beam has been achieved using a 2-m electrostatic hexapole field. Several |JKM > states were better resolved than the previous one in a CH3Cl/He supersonic beam. A voltage-modified trajectory simulation was carried out for fitting the observed focusing curve, in which the first-order approximation of the Stark effect was corrected in terms of the hexapole voltage in an empirical formula. A better agreement was found on the peak positions of the focusing curve, and the relative heights of the three peaks suggest that CH3I molecules in the present beam populate among the |JKM > states in a statistical way with a rotational temperature of 3 K.
  • Masahiro Manabe, Tetsuya Ito, Hideo Kawamura, Takumi Kinugasa, Yasushi ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 775-781
    Published: 1995
    Released: July 05, 2006
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    For the sodium l,2-bis(2-ethylhexyloxycarbonyl)ethanesulfonate (AOT)/water/dodecane system, the conductivity (κ) of the solution as well as the partial molar volume of water was determined at 25 °C as a function of the water concentration (CW) at a given concentration of AOT (CA). The value of (κ) increased stepwise through 2 peaks before water-phase separation. Each step was assigned as follows. Upon the initial additions of water at all of the CA’s studied (CA < 0.2 mol kg−1 (dodecane)), κ remained zero, indicating the formation of unionized hydrate, AOT(H2O)2. The critical composition of the solution for reversed micelle formation was estimated to be CA = ca. 0.02 and CW = ca. 0.04 mol kg−1 (dodecane). After hydrate formation, micelles were formed in equilibrium with the hydrate, at which point κ increased abruptly to the 1st peak. Coagulation of the micelles occurred above another critical composition (CA = 0.120 and CW = 0.612 mol kg−1), at which point κ increased with a steep slope up to the 2nd peak. The partial molar volume of water in the same system also indicated the formation of AOT(H2O)2.
  • Katsuhiko Nakamura, Yong-Zhong Da, Takahiro Jikihara, Hideaki Fujiwara
    1995 Volume 68 Issue 3 Pages 782-786
    Published: 1995
    Released: July 05, 2006
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    The thermochemical aspects of partition have been measured for multiply-substituted benzoic acids with the intention of disclosing the mode of change of the proposed novel hydrophobic parameters on multiple substitution in the phenyl ring. The substituent hydrophobic parameter (π) has been separated into two terms of enthalpic and entropic nature (πH and πS). It is necessary to take into account the effect of solvation around the hydrogen-bond-participating groups, such as OH, OCH3, and NO2, besides the benzoic CO2H in interpreting the substituent dependency of π, πH and πS. Some Hammett sigma parameters, such as σo(→OH) and σo(→OCH3), which mean the ortho substituent effect to the functional OH and OCH3 groups, respectively, act in a compensating manner to πH and πS, resulting in a vanishing effect on π. These trends are in good conformity with the enthalpy–entropy compensation rule in chemical thermodynamics.
  • Yasuyuki Takeda, Tatsuya Ezaki, Yoshihiro Kudo, Hiroaki Matsuda
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 787-790
    Published: 1995
    Released: July 05, 2006
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    In order to determine the standard ion-transfer potentials () of protonated amino acids (HA+) from water to an organic solvent of moderate dielectric constant, new theoretical equations were derived. Various theoretical predictions were verified experimentally by the solvent extraction of D- and L-amino acids with perchloric and nitric acid from water to nitrobenzene at 25 °C. Furthermore, the distribution constants (KD,A) of the electroneutral D- and L-amino acids (A) between water and nitrobenzene were determined at 25 °C. The amino acids were Ala, Val, Ile, Leu, Met, Phe, Thr, Asn, and Gln. The KD,A values of the D- and L-form of the same amino acid are equal. The same is true for the values. The hydrophilicity of A decreases in the following order: Asn > Thr > Gln > Ala > Val > Met > Ile ≥ Leu > Phe. The same order of decreasing hydrophilicity was also observed for HA+. All of the A and HA+ are much more soluble in water than in nitrobenzene. The A is more lipophilic than the corresponding HA+. Contributions of a methylene group to the distribution Gibbs-free energies of A were compared with those of HA+.
  • Kikuko Hayamizu, Shuji Okada, Takanori Doi, Hajime Kawanami, Naoto Kik ...
    1995 Volume 68 Issue 3 Pages 791-802
    Published: 1995
    Released: July 05, 2006
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    The effects of monomer alignment on the solid-state polymerizations of five octatetraynes and a butadiyne to produce polydiacetylenes were studied. Structural relaxations of the resulting polymers were found to occur over long time intervals. Solid-state high-resolution 13C NMR spectra were observed for six symmetrical monomers having alkyl chains (C14H29) and side chains containing either urethane or p-toluenesulfonate and the derived polydiacetylenes (PDA’s). The spin-lattice relaxation times (T1) of the PDA’s were also measured. The alignment and mobility of the monomers, which are closely related to the solid-state polymerizability and structure of the resulting polymers, are reflected in the solid-state 13C NMR spectra of the monomers.
    The PDA’s with urethane side chains were found to have slow structural relaxation. When the number of spacer methylenes between the acetylenic carbon and the urethane moiety is odd, a planar main-chain structure was assumed. It was found that PDA-4A’s having an odd number of spacer methylenes achieved a more homogeneous structure after long-term relaxation than a PDA-4A with an even number of spacer methylenes.
  • Takayuki Miyamae, Takehiko Mori, Kazuhiko Seki, Jiro Tanaka
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 803-809
    Published: 1995
    Released: July 05, 2006
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    The electrical conductivities of perchlorate-doped highly oriented polyacetylene films were measured from 290 to 1.5 K. The conductivity and its anisotropy were significantly enhanced by stretching. The value of the conductivity was 18000 S cm−1 at 190 K, and remained at 14000 S cm−1, even at 1.5 K. The extraordinary high conductivity at very low temperature showed that the film is really metallic. The temperature dependence of the conductivity could be expressed as the sum of two terms : One is almost a temperature-independent term, which may be due to a very weakly localized free carrier; the other is due to a three-dimensional variable-range hopping mechanism of a more localized carrier. The conduction mechanism is discussed in terms of the polson model of doped polyacetylene.
  • Ryotaro Kiyono, Yoshiharu Niimi, Masayasu Tasaka
    1995 Volume 68 Issue 3 Pages 810-815
    Published: 1995
    Released: July 05, 2006
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    The dependence of the electric potential difference on time under a pressure gradient across hydrogel membranes, obtained by esterification of poly(vinyl alcohol) and poly(acrylic acid), was measured. At the moment when a pressure difference was applied, a sharp spike of the electric potential difference was observed. The overall variation of the electric potential difference on time consisted of two different processes. One of them, which gradually increased with time, and finally reached a steady-state value, reflects a relaxation of polymer chains dissolved in the liquid phase of the gel membrane under the pressure difference. The other, which showed a sharp inverse spike just after applying the pressure difference, and reached zero immediately, may have been caused by a transformation of the membrane matrix due to a sudden change in pressure before the migration of the water, that is, by compaction of the membrane matrix. When hydrogen molecules of the carboxyl groups in the gel membrane were exchanged with potassium ions, the gel membrane expanded. The relationship between the magnitude of the electric potential difference for each of the forms and the properties of the membranes is discussed.
  • Sushil Chandra Tiwari, K. N. Sharma, Hemlata Mohabey
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 816-818
    Published: 1995
    Released: July 05, 2006
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    A new reagent N-hydroxy-N-(o-chlorophenyl)-N′-(p-methoxyphenyl)benzamidine hydrochloride, has been synthesized and is characterized on the basis of mp, elemental analysis, IR and UV spectra. The reactions of the reagent with metal ions suggest that new methods can be developed for gravimetric and extraction spectrophotometric determination of metal ions. The reagent has been successfully used for the extraction-spectrophotometric determination of vanadium(V) in presence of phenol. Many common ions including Co2+, Zn2+, Ag+, Mn2+, etc. do not interfere in the determination. The method has been applied for the determination of vanadium in steel samples.
  • Takafumi Miyanaga, Hideto Sakane, Iwao Watanabe
    1995 Volume 68 Issue 3 Pages 819-824
    Published: 1995
    Released: July 05, 2006
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    The EXAFS (Extended X-Ray Absorption Fine Structure) spectra of hydrated transition metal complexes were measured to investigate the relation between the Debye–Waller factor in EXAFS, σ2, and their ligand exchange reaction rate constant, k1, in aqueous solution. A good correlation between these two factors was obtained for various transition metal ions. The relation between σ2 and log k1 is studied theoretically using the Arrhenius theory. The introduction of an anharmonic Morse function as the interaction potential was found to lead to a simple expression connecting σ2 and log k1, which is in accordance with the experimental results. It is also found that k1 correlates not only with σ2 but also a third order cumulant in EXAFS, C3; the greater the k1 value, the greater the increase in C3 with temperature. The behavior of C3 implies that the anharmonicity in the potential of the metal–oxygen interaction must be taken into consideration for the study of the ligand exchange reaction.
  • Shoichi Aizawa, Hideo Akaiwa
    1995 Volume 68 Issue 3 Pages 825-830
    Published: 1995
    Released: July 05, 2006
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    The distribution and the mode of occurrence of fluorine in Holocene (mainly high-Mg calcite), Pleistocene (low-Mg calcite), and Paleozoic (low-Mg calcite) limestones of Yoron-jima Island were investigated, and the geochemical behavior of F during the formation of Pleistocene limestones is discussed. The average F contents of Holocene (n = 3), Pleistocene (n = 20), and Paleozoic (n = 8) limestone samples are 680, 99, and 45 ppm, respectively, showing a marked decrease of this element during early diagenetic processes of marine carbonates. A positive correlation between the F and Mg contents of Pleistocene limestones indicates that F might have been removed together with Mg2+ from high-Mg calcite into interstitial waters during these processes. A main mode of occurrence of F (about 50%) in Pleistocene limestones is confirmed to be carbonate fluorapatite (francolite), and the rest is thought to be fluorite.
  • Akira Hanaki
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 831-837
    Published: 1995
    Released: July 05, 2006
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    Kinetic studies on a role of dioxygen in the copper-catalyzed autoxidation of cysteine in glycylglycine-phosphate buffers have been carried out. The rate of autoxidation was obtained by measuring the consumption of cysteine. It has been revealed that cysteine is oxidized by a “sequential mechanism”. The reaction pathway can be shown by Eqs. 1, 2, 3, and 4; cysteine is oxidized not only by copper(II) species, but also by copper(I)–O2 adducts:

    Here, L represents ligands including cysteine. The oxidation step (4) catalyzed by the Cu(I)–O2 species was proposed to be rate-determining.
  • Isao Kawafune, Gen-etsu Matsubayashi
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 838-842
    Published: 1995
    Released: July 05, 2006
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    The kinetics of the oxygen-atom transfer reactions of α-[NBun4]3[PMo12O40] (abbreviated PMo12) and of A-β-[NBun4]3[PMo3W9O40] (abbreviated PMo3W9) with PPh3 were investigated in acetonitrile at 23—82 °C. Each reaction is first order in both the heteropolyanion salt and PPh3. The second-order rate constants at 23 °C are k2 = 6.53 × 10−4 and 4.58 × 10−5 (dm3 mol−1 s−1) for the reduction of PMo12 and PMo3W9, respectively. The difference in the k2 values is attributed to the number of active sites for oxygen transfer; PMo3W9 has only three corner-sharing oxygen atoms in the Mo(VI)–O–Mo (VI) bonds, whereas there are twelve corner-sharing and twelve edge-sharing oxygen atoms in PMo12. The activation parameters are, however, almost identical for both reactions: ΔH = 43.6 and 43.4 (kJ mol−1) and ΔS = −158 and −181 (J K−1 mol−1) for the reduction of PMo12 and PMo3W9, respectively. These results suggest a similar transition state in the oxygen-atom transfer reactions via the Mo–O–Mo sites of PMo12 and PMo3W9.
  • Hiromasa Kurosaki, Sayuri Koga, Masafumi Goto
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 843-851
    Published: 1995
    Released: July 05, 2006
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    Mono N-ethylethanediamine and N-benzylethanediamine complexes of Co(III), Fe(II), and Fe(III) with four cyano or ammine groups were prepared. Their 1H NMR spectra were measured to determine the conformation of N-ethyl and N-benzyl groups. These N-alkyl groups take pseudo-equatorial orientation at the coordinated secondary amine. The most preferred conformation is that the methyl and phenyl groups are anti with respect to the central metal ions. The crystal structure parameters of [Co(NH3)4(N-benzylethanediamine)](NO3)3·1.5H2O were determined: P21, Z = 2, a = 8.639(3), b = 21.240(3), c = 10.897(2) Å, β = 94.11(1)°. The crystallographically independent Co complex cations had opposite absolute configuration around coordinated secondary amine sites and the benzyl groups are anti to the cobalt atom.
  • Mutsuo Kodama, Eiichi Kimura
    1995 Volume 68 Issue 3 Pages 852-857
    Published: 1995
    Released: July 05, 2006
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    The complex formation reactions of aluminum ions with polyamino polycarboxylic macrocycles (DOTA, TETA, PEPA, and HEHA) in an aqueous solution were investigated using a potentiometric method. At a pH higher than 5.00 the tetradecamer, [Al14(OH)34]8+, was found to be the most consistent uncomplexed Al(III) species based on our experimental data. Under the experimental conditions employed, aluminum ions form solely 1 : 1 ratio complexes with all of the ligands studied. Polyaza rings of the ligands may act simply as a frame to constrain the carboxylate groups into a nearly spherical arrangement; DOTA, TETA, PEPA, and HEHA act as tetra-, penta-, and hexa-dentate ligands, respectively, wrapping themselves around the aluminum(III) ion.
  • Eiko Toyota, Keisuke Umakoshi, Yoshihisa Yamamoto
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 858-865
    Published: 1995
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    The title complexes of cis-β1-(RR,SS)-, cis-β1-(RS,SR)-, cis-β2-(RR,SS)-, and cis-β2-(RS,SR)-[Co(A)(trien)]Cl·nH2O and cis-β1-(RR,SS)-, cis-β1-(RS,SR)-, and cis-β2-(RR,SS)-[Co(B)(trien)]Cl2 have been obtained from a reaction mixture of cis-α-[CoCl2(trien)]Cl, Ag2O, and salicylaldoxime (Chart 1).

    Separations of the A- and B-type complexes, and of the geometrical isomers of cis-β1 and β2, as well as those of the diastereoisomers of (RR,SS) and (RS,SR) were attempted by using Dowex 50W-X2 column chromatography. The B-type complexes were obtaind from the reaction mixture of the corresponding A-type complexes and hydrochloric acid. The structure of cis-β1-(RS,SR)-[Co(A)(trien)]Cl·(CH3COCH3)·2H2O has been confirmed by an X-ray analysis. Crystal data: CoC16H33N5O5Cl, orthorhombic, Pb21a, a = 14.091(2), b = 22.385(3), c = 7.011(2) Å, V = 2211.5(6) Å3, Z = 4, and R = 0.076. A property between A- and B-type complexes has been compared in the IR, NMR spectra, and electric conductivity in aqueous solution; i.e., the CH=N streching vibrations (ca. 1590 cm−1) of A-type complexes have a lower wavenumber than those (ca. 1600 cm−1) of B-type complexes. The chemical shifts (δ = 148—150) of the CH=N carbon signal of A-type complexes are at a higher field than those (δ = 160—162) of B-type complexes in D2O. The chemical shifts (δ = 7.9—8.0) of the CH=N proton signal of A-type complexes are at a higher field than those (δ = 8.2—8.4) of B-type complexes in D2O. The electric conductivities in aqueous solutions of A- and B-type complexes were ca. 120 and ca. 220 S cm2 mol−1, respectively. The absorption spectra of cis-β-(RS,SR)-isomers and the corresponding (RR,SS)-isomers showed two peaks at around 350 and 540 nm and three peaks at around 350, 470, and 540 nm, respectively.
  • Masanobu Tsuchimoto, Yasuhiro Ito, Junnosuke Fujita
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 866-873
    Published: 1995
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    Five new macrocyclic ligands which form a large (10—15) chelate ring upon coordination (1,4,8,11-tetraazacyclooctadecane(232N410), -cyclononadecane(232N411), -cycloicosane (232N412), -cyclohenicosane(232N413), and -cyclotricosane(232N415)), and the Co(III) complexes, trans-[CoCl2(232N4x)]+ (x = 7—13, 15) were prepared and characterized. Of six isomers arising from the combination of four chiral nitrogen donor atoms in this type of complex, three and two isomers were obtained, respectively, for complexes with x = 7 and 8, and x = 9—13 and 15. The ligand field parameter of the nitrogen donor atom (Δ(N)) of 232N4x decreases largely from x = 6 to 7, and then shows a small fluctuation with a small decrease at x = even-numbers and a small increase at x = odd-numbers, while a smaller change is observed for the parameter of the chloride ion (Δ(Cl)). The reduction potential for the Co(III)/Co(II) couple (E1/2) shifts to the positive side from the complex with x = 6 to those with x = 7 and 8, and then shows a small change depending on the ring members. The ΔEp(EpaEpc) values of complexes with x = 8—11 are large, indicating an instability of the medium-sized chelate Co(II) complexes.
  • Hiroshi Kawaguchi, Miyuki Yoshida, Toshiaki Yonemura, Tomoharu Ama, Ke ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 874-882
    Published: 1995
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    Some cobalt(III) complexes with Co–C σ-bond have been prepared by photodecarboxylation reactions of the complexes containing ethylenediamine-N,N′-dipropionate (eddp) or its analogs. The crystal structure of α-[Co(Me2eedmp-C,N,N′,O)(en)]+ (Me2eedmp: CH2CH2N(CH3)(CH2)2N(CH3)(CH2)2COO), which is the photolysis product of α-[Co(Me2eddp)(en)]+ (Me2eddp: {CH2N(CH3)(CH2)2COO}2), was determined by the X-ray diffraction method. The crystal is monoclinic, space group P21/n, a = 9.013(2), b = 13.420(1), c = 14.754(4) Å, β = 92.75(1)°, V = 1782.5(6) Å3, Z = 4, and R = 0.038. The coordination of C atom to Co center results in elongation of the Co–O bond located in the trans position of the C atom, compared with usual Co–O bonds. The photolysis products of optically active isomers (Λ-α, Λ-β(1), and Λ-β(2)) of [Co(eddp)(en)]+ were studied on the basis of the absorption, CD, and 13C NMR spectral data. The photolysis of Λ-β(1) provided Δ-α-[Co(eedmp-C,N,N′,O)(en)]+ (eedmp; CH2CH2NH(CH2)2NH(CH2)2COO), while the photolysis of Λ-β(2), which is a conformational diastereomer of Λ-β(1), provided (−)CD543-β-[Co(eedmp-C,N,N′,O)(en)]+ (major product) and Λ-α-[Co(eedmp-C,N,N′,O)(en)]+. Optically active (+)CD553-β-[Co(etnmp-C,N,N′,O)(en)]+ (etnmp: CH2CH2NH(CH2)3NH(CH2)2COO) was obtained by the photolysis of Δ-(−)CD505-β-[Co(tndp)(en)]+ (tndp: CH2{CH2NH(CH2)2COO}2).
  • Kazuo Kashiwabara, Masakazu Kita, Hideki Masuda, Saeko Kurachi, Shiger ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 883-888
    Published: 1995
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    The crystal structures of trans-[Co(acac)2(PMePh2)2]PF6 (acac = 2,4-pentanedionate ion) (1), trans-[Co(acac)2(H2O)(PMePh2)]ClO4 (2), and trans(P,P)-[Co(acac)(CN)2(PMePh2)2] (3) were determined by the X-ray diffraction method. Complex 1 crystallizes in the monoclinic, space group P2/n, with two molecules in a unit cell of dimensions a = 17.151(2), b = 10.347(2), c = 10.996(2) Å, β = 107.84(1)°, V = 1857.6(6) Å3. Complex 2 crystallizes in the monoclinic, space group P21/c, with four molecules in a unit cell of dimensions a = 10.161(3), b = 17.291(5), c = 14.938(3) Å, β = 91.76(2)°, V = 2623(1) Å3. Complex 3 crystallizes in the monoclinic, space group C2/c, with four molecules in a unit cell of dimensions a = 21.628(1), b = 8.974(1), c = 16.203(1) Å, β = 106.396(2)°, V = 3012.9(1) Å3. The Co–P bond length for complex 1, 2.329(1) Å, is significantly longer than those for complexes 2 (2.213(1) Å) and 3 (2.2698(4) Å). These lengths are discussed with the hydrolytic properties.
  • Hiroki Oshio, Etsuo Ino, Tasuku Ito, Yonezo Maeda
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 889-897
    Published: 1995
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    Metal complexes with TCNQ as ligands, [MnIII(salen)(TCNQ)0.5][MnIII(salen)(TCNQ)0.5(CH3OH)]CH3OH·H2O (1) and [FeII(CH3OH)4(TCNQ)2]TCNQ·2CH3CN (2) (where TCNQ and H2salen represent tetracyanoquinodimethane and quadridentate schiff base N,N′-disalicylideneethylenediamine, respectively) were prepared, and crystal structures and magnetic properties were studied. Complex 1 crystallizes in the triclinic space group with cell constants a = 12.000(6), b = 19.986(7), c = 9.494(6) Å, α = 100.67(5), β = 100.01(5), γ = 81.50(4)°, V = 2188(2) Å3, and Z = 2. In 1, two distinct six-coordinate [MnIII(salen)]+ chromophores are bridged by two kinds of TCNQ2− anions (A and B) in μ2 and μ4 fashions to form a one-dimensional structure. Complex 2 crystallizes in the triclinic space group with cell constants a = 10.523(1), b = 14.008(2), c = 8.062(1) Å, α = 94.96(1), β = 111.11(1), γ = 79.96(1)°, V = 1091.3(3) Å3, and Z = 1. In 2, mono-anionic and neutral TCNQ molecules (C and D, respectively) stacks to form columns (···DCCD···), which are linked by the coordination of the nitrile group to [FeII(CH3OH)4]2+. Temperature dependent magnetic susceptibility measurements revealed that magnetic interactions between metal centers in 1 and 2 are very small.
  • Hideyuki Sawatari, Takaaki Asano, Xincheng Hu, Tomoo Saizuka, Akihide ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 898-904
    Published: 1995
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    The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4—30 ng ml−1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides.
  • Fathy Mohamed Abdel Aziz El-Taweel, Salah Zaki Ahmed Sowellim, Abdel G ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 905-910
    Published: 1995
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    Whereas 2H-pyrano[3,2-c]quinoline-2,5(6H)-dione (2a) or 3-acetyl-1-methyl-2(1H)-quinolinone (3a) reacted with the benzylidenenitriles 1af or a mixture of either malononitrile or ethyl cyanoacetate and aromatic aldehydes in ethanol/piperidine to give 4H-pyran derivatives 8, the reaction of 2b,c or 3b,c with the same reagents afforded 4,6-dihydro-5H-pyrano[3,2-c]quinolin-5-ones 11. Compounds 11 were also prepared from 1af and 3d,e,f. Reaction of pyrano[3,2-c]coumarin 2d with 1a yielded 6H,11H-[2]benzopyrano[4,3-c][1]benzopyran-6,11-dione (15). Treatment of 17 with aqueous potassium cyanide or hydroxylamine afforded the 2(1H)-quinolinone derivatives 19 and 20 respectively.
  • Takanori Shibata, Yuji Koga, Koichi Narasaka
    1995 Volume 68 Issue 3 Pages 911-919
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    Intramolecular allene–alkyne coupling reactions proceed in the presence of Fe(CO)4(NMe3) under photoirradiation conditions to provide various bicyclic dienones through η3-allyl iron complexes. Various 4-methylene-2-cyclopenten-1-ones could be prepared by intermolecular allene–alkyne coupling reaction under the same reaction conditions.
  • Takashi Karatsu, Akihide Kitamura, Hualing Zeng, Tatsuo Arai, Hirochik ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 920-928
    Published: 1995
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    On triplet sensitization, 1-styrylanthracene (1SA) undergoes adiabatic cis → trans one-way isomerization (3c*3t*) similarly to 2-anthrylethylenes. However, upon direct irradiation, cis-1SA in the singlet excited state mostly undergoes cyclization to a dihydrophenanthrene-type product (DHP), 4a,4b-dihydrobenzo[b]chrysene, competing with an inefficient intersystem crossing to 3c* followed by one-way isomerization. The produced DHP, in deaerated benzene, is reverted to cis-1SA by a thermal (Ea = 14.9 kcal mol−1) or a photochemical pathway; however, under an oxygenated atmosphere DHP gives benzo[b]chrysene. A failure in the production of a cyclized product upon the excitation of trans-1SA shows that the isomerization really takes place in a one-way fashion.
  • Reda M. El-Shishtawy, Koushi Fukunishi
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 929-934
    Published: 1995
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    The synthesis of long chain malachite green leuco base (LMGH) is reported. The absorption spectra of LMGH in different solvents seem to be independent of the solvent polarity (dielectric constant), while the emission spectra are dependent on it. Slight fluorescence self-quenching of LMGH in methanolic solution appears at a concentration of ca. 4 × 10−5 mol dm−3 and it becomes the dominant factor above 2 × 10−4 mol dm−3. The effect of the long chain on the basicity of LMGH relative to that of malachite green leuco base (MGH) can be revealed by the fluorescence quenching of both compounds by Fe3+. The quenching process obeys a static type of mechanism, which is followed by an electron transfer of LMGH to Fe3+. The fluorescence quenching efficiency of micellized LMGH by Fe3+ is very dependent on the charge of the micelle, and is most effective in sodium dodecyl sulfate (SDS) micelle. The color appearance of the dye from LMGH upon mixing with Fe3+, is easily observed in methanol, but not in SDS micelle. The critical micelle concentrations (cmc) of anionic (SDS) and cationic (hexadecyltrimethylammonium chloride, CTAC) micelles have been estimated using LMGH as a probe.
  • Hidetoshi Tokuyama, Hiroyuki Isobe, Eiichi Nakamura
    1995 Volume 68 Issue 3 Pages 935-941
    Published: 1995
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    Vinylcarbene species generated by thermolysis of cyclopropenone acetal (CPA) reacts with C60 in a [1 + 2] and a [3 + 2] manner to afford, at 80 °C, methano- and propanofullerene derivatives as a 10 : 1 mixture. The periselectivity depends on the reaction temperature; the ratio of the [1 + 2] and [3 + 2] cycloadducts changed to 2 : 1 and to 7 : 93 in the reaction at 100 and 140 °C, respectively. Temperature dependence was also observed in the reaction of phenyl-substituted CPA. The reactions of ethyl- and trimethylsilyl-substituted CPAs, which proceeded only at 150—170 °C, afforded propanofullerenes as a sole product. The reaction of the substituted CPAs proceeded exclusively via a terminally substituted vinylcarbene species.
  • Kaoru Inami, Tadashi Teshima, Hideaki Miyashita, Tetsuo Shiba
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 942-949
    Published: 1995
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    A chemical synthesis was performed of an octapeptide with a phosphonic ester linkage, which corresponds to a variation of the partial sequence of a gene product of erb B-2. The phosphonic ester linkage was successfully prepared through a coupling reaction of magnesium salt of the hydroxypeptide with phosphonochloridate, without damage of the peptide bond. The free aminophosphonic peptide as the final product gave a single peak on the ODS column, and a reasonable ratio of the component amino acids. The reaction series exploited here might be useful as a general procedure for preparation of the phosphonic peptide.
  • Chan Sik Cho, Yasuharu Yoshimori, Sakae Uemura
    1995 Volume 68 Issue 3 Pages 950-957
    Published: 1995
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    Triarylbismuthines react with carbon monoxide (CO) at atmospheric pressure in acetonitrile at 25 °C in the presence of a catalytic amount of a rhodium compound such as [RhCl(CO)2]2, RhCl3·3H2O, and [RhCl(COD)]2 to give the corresponding diaryl ketones in high yields. If methanol is used as the solvent, methyl benzoates are also produced. When similar reactions are carried out in methanol in the presence of a catalytic amount of palladium(II) acetate together with potassium carbonate in place of the rhodium compound, methyl benzoates are formed as the sole carbonylation products. The oxidative addition of a carbon–bismuth bond to rhodium(I) and palladium(0) is proposed as the key step of these carbonylation reactions.
  • Sachiko Tojo, Kazuhiro Morishima, Akito Ishida, Tetsuro Majima, Setsuo ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 958-966
    Published: 1995
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    The reaction of the stilbene radical cation formed by pulse radiolysis or γ-radiolyses is explained based on neutralization as well as the formation of a π-type stilbene dimer radical cation (π-St2+•), converting to the σ-type St2+• (σ-St2+•). The r-1,c-2,t-3,t-4-tetraphenylcyclobutane radical cation generated in a rigid matrix at 77 K which converted to σ-St2+• upon warming. Both r-1,c-2,t-3,t-4- and r-1,t-2,c-3,t-4-tetraphenylcyclobutane radical cations underwent photochemical cycloreversion to π-St2+• upon irradiation at wavelengths longer than 390 nm at 77 K, and converted to σ-St2+• upon warming. It is suggested that π-St2+• has overlapping arrangements of π-electrons, while σ-St2+• has radical and cation centers on the 1- and 4-positions of the C4 linkage.
  • Masaya Nakata, Takashi Ishiyama, Shinichi Akamatsu, Youichi Hirose, Hi ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 967-989
    Published: 1995
    Released: July 05, 2006
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    The oligomycin B spiroketal portion, [2S,2(2R),3S,6R,8S,8(3R),9S,10R,11S]-2-[2-(t-butyldiphenylsilyloxy)propyl]-8-[3-(hydroxymethyl)pentyl]-3,9,11-trimethyl-1,7-dioxaspiro[5.5]undecane-5,10-diol (2), and polypropionate portion, ethyl (2E,4S,5R,6R,7S,8S,9R,10S,12R,13S,14R,16E)-5-(t-butyldimethylsilyloxy)7,9-(isopropylidenedioxy)-12,13-(4-methoxybenzylidenedioxy)-4,6,8,10,12,14-hexamethyl-11-oxo-18-phenylsulfonyloctadeca-2,16-dienoate (3), have been synthesized. The C19-C21 Wittig salt, [(2S,3R)-2-ethyl-3,4-(isopropylidenedioxy)butyl]triphenylphosphonium iodide (6), prepared from 2-butene-1,4-diol via Sharpless epoxidation, was coupled with the C22-C27 aldehyde, benzyl 2,4-dideoxy-3-O-(4-methoxybenzyl)-2,4-di-C-methyl-α,β-L-galacto-hexodialdopyranoside-(1,5) (7), prepared from (Z)-2-butene-1,4-diol via Sharpless epoxidation and the Brown’s crotylboration. The resulting coupling product was transformed to the C19-C27 lactone, [3S,4R,5R,6S,6(3R,4R)]-6-[3-ethyl-4,5-(isopropylidenedioxy)pentyl]-4-(4-methoxybenzyloxy)-3,5-dimethyl-3,4,5,6-tetrahydro-2H-pyran-2-one (4). The C28-C34 organostannane compound, (2R,4S,5S,7RS)-2-(t-butyldiphenylsilyloxy)-5-methyl-7-(tributylstannyl)-4-(triethylsilyloxy)-7-[(2-trimethylsilylethoxy)methoxy]heptane (5b), was prepared from (R)-methyl 3-hydroxybutyrate via the Brown’s crotylboration and the Still’s stannylation. After lithiation of 5b with butyllithium, the resulting α-alkoxy organolithium compound was coupled with 4 and the product was converted to the C19-C34 spiroketal, [2S,2(2R),3S,6R,8S,8(3R,4R),9S,10R,11S]-2-[2-(t-butyldiphenylsilyloxy)propyl]-8-[3-ethyl-4,5-(isopropylidenedioxy)pentyl]-10-(4-methoxybenzyloxy)-3,9,11-trimethyl-1,7-dioxaspiro[5.5]undecan-5-ol (37). The synthetic 2, derived from 37, was identical to the oligomycins (A, B, C mixture) degradation product in all respects, which elucidates the absolute stereochemistry of oligomycin B (1b). The C3-C9 aldehyde, (2-trimethylsilylethoxy)methyl 2,4,6-trideoxy-3-O-(4-methoxybenzyl)-2,4,6-tri-C-methyl-D-glycero-α-L-ido-heptodialdopyranoside-(1,5) (9), was prepared from (2S)-3-(t-butyldimethylsilyloxy)-2-methylpropanal via Keck’s crotylstannane addition and Brown’s crotylboration. The aldol coupling between the zinc enolate of the C10-C16 ketone, t-butyldimethylsilyl 2,3,7,8-tetradeoxy-4-O-(4-methoxybenzyl)-3,5-di-C-methyl-α-L-xylo-octopyranosid-6-ulose (10), prepared from methyl (R)-(+)-lactate via Brown’s crotylboration and a metallated methoxyallene addition, and aldehyde 9 gave the C8-C9 syn, C9-C10 syn product, which was transformed to the oligomycin B polypropionate portion 3 through elongation of the C1-C2 and C17-C18 carbon units.
  • Yoshiharu Nakamura, Akio Tanaka, Satoko Okubayashi, Hidemi Tera, Teruo ...
    1995 Volume 68 Issue 3 Pages 990-996
    Published: 1995
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    Conjugated oxidoreductase reactions across membranes prepared from PVA or polyurethane containing amino components were driven between systems of glucose 6-phosphate dehydrogenase (G6PD)/glucose 6-phosphate (G6P)/NADP+ and glutathione reductase (GR)/glutathione oxidized form (GSSG)/NADPH. In order to obtain the optimum reaction system, membranes were prepared, while considering the membrane composition, membrane thickness, and membrane density. The kinetics and the mechanism of the conjugated transmembrane reaction systems have been discussed.
    Consequently, it has been found that the coenzyme molecules adsorbed in the membrane can act as electron carriers, and that the used hydrogel membrane should be as dense as possible and positively charged.
  • Hideo Nakamura, Hiromi Matsuhashi
    1995 Volume 68 Issue 3 Pages 997-1000
    Published: 1995
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    The oxidizing reagents in a heterogeneous system were obtained by impregnating Zr(OH)4 with NH4VO3 and (NH4)2CrO4 followed by calcination in air at 773 K. These materials (V2O5/ZrO2 and CrO3/ZrO2) converted alcohols into their corresponding aldehydes or ketones at moderate temperatures in a solvent with very high selectivity. Changes in the oxidation states of vanadium and chromium were investigated by a temperature-programmed reduction method (TPR). A linear relation was found between the yield of cyclohexanone formed from cyclohexanol and the amount of reduced vanadium or chromium, determined by TPR. It was confirmed that the active species of V(V) and Cr(VI) were reduced to V(II) and Cr(IV), respectively, in the oxidation process.
  • Jiachang Yao, Hisatomo Yonehara, Chyongjin Pac
    1995 Volume 68 Issue 3 Pages 1001-1005
    Published: 1995
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    High-yield synthesis of pure oxo(phthalocyaninato)titanium(IV) was conveniently achieved by heating a mixture of 1,2-dicyanobenzene, titanium(IV) butoxide, urea, and 1-octanol at 150 °C. It is suggested that a key pathway of the efficient condensation reaction is the complex formation of titanium(IV) butoxide with ammonia generated by the nucleophilic attack of 1-octanol to urea. Applicabilities of this method were investigated for condensation reactions of 1,2-dicyanobenzene with other metal alkoxides.
  • Joo Eun Chung, Hiromi Sakai, Shinji Takeoka, Hiroyuki Nishide, Eishun ...
    1995 Volume 68 Issue 3 Pages 1006-1011
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    Solid hemoglobin (Hb) films were prepared by casting from a mixed solution of human hemoglobin and maltose (wt ratio of Hb/maltose is 60/40). The behavior of O2 and CO in coordinating to Hb in the films was then observed. The coordination equilibrium constants of both ligands were smaller by about an order of magnitude, and the rate constants (kon and koff) were smaller by about 13 orders of magnitude, than those of aqueous solutions of Hb. Interestingly, O2 and CO saturation was limited to 52% and 86%, respectively, under a partial pressure of 760 Torr (1 Torr = 133.322 Pa) of each gas, in spite of the one-to-one ligand binding ratio in aqueous solutions. This is due to the restraint of the structural change from a tense to a relaxed state in the solid phase. The limited saturation of the coordination in the solid phase was found to increase to 100% when a small amount (5.9%) of water was added; a significant structural change from the tense to the relaxed states followed.
  • Shigeru Kunugi, Yuuji Hayashi, Akira Koyasu, Naoki Tanaka, Makoto Shir ...
    1995 Volume 68 Issue 3 Pages 1012-1018
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    In order to understand the effect of the structures of the surrounding medium on biocatalytic reactions, hydrolytic catalysis by subtilisin Carlsberg in a ternary system containing octyl β-D-glucopyranoside (β-OG), water, and octanol (OcOH) was studied, with special reference to the enzyme reactivity and the morphology of the surfactant aggregates.
    First, the effect of β-OG and other alkyl D-glucopyranosides (AG) on the subtilisin reaction was studied in the surfactant/water binary system; all four surfactants tested were found to inhibit the subtilisin catalysis.
    Then, a detailed phase diagram of β-OG/water/octanol was determined and several liquid crystalline phases were found.
    When the subtilisin reactions were measured in several compositions in the phase diagram, the maximum of the apparent rate was observed in reversed micells as well as in the reversed hexagonal phase at a certain [water]/[surfactant] ratio (wo). The apparent optimal wo was calculated to be around 5—6. These results were compared with the results in another ternary system of Aerosol OT/water/isooctane.
  • Shigeru Kunugi, Noriko Suzuki, Akira Sakamoto, Masumi Yoshida
    1995 Volume 68 Issue 3 Pages 1019-1023
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    The effect of an organic solvent on the thermolysin-catalyzed peptide condensation reaction from acylamino acid and amino acid amide was investigated. Profiles of the apparent equilibrium yield were roughly divided into three regions: precipitation-driven (mostly low to medium organic-solvent concentration), clear and homogeneous (middle to rather high concentration), and inactivated conditions (very high (>80%) concentration).
    In the second, homogeneous region (70%(v/v) DMSO), the kinetics of the condensation reaction were followed by taking into account the simultaneous, solvent-induced gradual inactivation of the enzyme. The dependence on the carboxyl component concentration gave apparent Km and kcat parameters for Cbz–Phe and Cbz–Trp; we found that even at 70% DMSO, thermolysin had similar rate parameters and activity to those in 10% DMSO [Wayne and Fruton, Proc. Natl. Acad. Sci. U.S.A., 80, 3241 (1983)]. The amine-component concentration dependence showed distinct substrate-inhibition profiles for both LeuNH2 and PheNH2.
  • Masaki Okazaki, Nobuhiko Uchino, Nobuharu Nozaki, Kazumi Kubo
    1995 Volume 68 Issue 3 Pages 1024-1029
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    A weak absorption of laser light by a nonlinear optical crystal causes a noticeable temperature rise in the crystal. Such absorption may undesirably shift the reflactive indices (some optical characteristics) of the crystal. 3,5-dimethyl-1-(4-nitrophenyl)pyrazole [DMNP], an excellent nonlinear optical material, was deuterated in order to suppress its absorption in the 1 μm wavelength region.
    Three deuterated deriatives were synthesized; their crystal structures were identical with that of DMNP. The deuteration of the pyrazole part including the two methyl moieties proved to be more effective than deuteration of the phenyl part (benzene ring) with regard to a reduction of the IR absorption.
    A good correlation was confirmed between the temperature elevation under laser irradiation and IR absorption.
  • Shinichi Hirano, Naoya Shigemoto, Shinichi Yamada, Hiromu Hayashi
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 3 Pages 1030-1035
    Published: 1995
    Released: July 05, 2006
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    A modified chemical-absorption method capable of cyclic fixed-bed operations under moist conditions for the recovery of carbon dioxide from flue gases has been proposed employing K2CO3-on-carbon. Deliquescent potassium carbonate was favorably supported on activated carbon as well as on bound carbon dioxide in the presence of water vapor by the following reaction:

    After breakthrough, the entrapped carbon dioxide was released by the decomposition of hydrogencarbonate at a higher temperature above 150 °C to shift the reaction in reverse by steam, which could be condensed by cooling to afford high-purity carbon dioxide. An effective use of the pore space as microtanks for aqueous potassium carbonate was verified with XRD evidence under a very humid condition of 7.3% H2O, as anticipated. The amount of CO2 uptake was very small under a dry condition, but increased abruptly in the presence of moisture. Potassium carbonate on carbon was crystalline 2K2CO3·3H2O, even when in contact with moisture of 1.7% H2O; this revealed that it is not necessary for K2CO3 to be in the aqueous phase. Illustrative cyclic fixed-bed operations for the recovery of carbon dioxide under a condition close to the actual flue gas of 13.8% CO2 with 10% H2O at 100 °C under atmospheric pressure were demonstrated up to 10 cycles.
  • Takayuki Suzuki, Yuji Soejima, Hiroyuki Nishide, Eishun Tsuchida
    1995 Volume 68 Issue 3 Pages 1036-1041
    Published: 1995
    Released: July 05, 2006
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    Oxygen transport was facilitated in polymer membranes bonded with new derivatives of [meso-α,α,α,α-tetrakis(o-pivalamidophenyl)porphyrinato]cobalt (CoPs). The oxygen-binding reactivity of fixed CoPs strongly influenced the facilitated oxygen transport. CoP having a larger cavity structure showed a more rapid reactivity and achieved a higher oxygen permeability in the membrane. There existed correlations of the oxygen-binding and -dissociation rate constants with the diffusion constant of oxygen via CoPs fixed in the membrane.
  • Masaki Matsui, Shigeru Kondoh, Katsuyoshi Shibata, Hiroshige Muramatsu
    1995 Volume 68 Issue 3 Pages 1042-1051
    Published: 1995
    Released: July 05, 2006
    JOURNALS RESTRICTED ACCESS
    The reactions of 1,4-benzo-, naphtho-, and 9,10-anthraquinones with bis(perfluoroalkanoyl) peroxides gave the corresponding perfluoroalkylated derivatives. Those of 2-methyl- and 2-[4-(chloroanilino)]-1,4-naphthoquinones with bis(oxaperfluoroalkanoyl) peroxides afforded the dichloromethyl and trifluoromethyl derivatives, respectively. Absorption bands of the perfluoroalkylated naphtho- and anthraquinone dyes showed a slight hypsochromic shift. The solubilities of the perfluoroalkylated anthraquinone dyes into hexane were much more higher than those of the non-perfluoroalkylated ones.
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