Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 65 , Issue 11
Showing 1-50 articles out of 57 articles from the selected issue
  • Yoshinobu Nishimura, Hirochika Sakuragi, Katsumi Tokumaru
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 2887-2893
    Published: 1992
    Released: July 29, 2006
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    Electron transfer from the triplet state of xanthene dyes (F1In2− and F1Brn2−, n = 2, 3, and 4) to methylviologen (MV2+) was investigated with a laser flash photolysis technique. Efficiency for the charge separation in aqueous organic solution to give free radical ions, F1In−• or F1Brn−• and MV+•, increased almost linearly with increasing mole fraction of added organic solvents such as acetonitrile, acetone, dioxane, ethanol, methanol, and DMSO in the decreasing order of efficiency. The effect of organic solvents on dissociation of radical ion pairs tends to increase with decrease of their hydrogen-accepting property expressed by Taft’s β value. Halogen-atom substitution in F1In2− and F1Brn2− reduced the MV+ yield, and this heavy-atom effect is associated with increase in the rate of recombination of triplet radical ion pairs accompanying spin inversion.
  • Yasuki Nakashima, Hiroyuki Kanada, Moritaka Fukunaga, Keiko Suzuki, Ke ...
    1992 Volume 65 Issue 11 Pages 2894-2900
    Published: 1992
    Released: July 29, 2006
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    The deuterium isotope effects on the 13C NMR chemical shifts of the ring carbons of aromatic heterocycles were investigated. One-bond shifts are correlated with the C–H bond lengths calculated by the MNDO MO method. Two-bond shifts are dependent on the nature of the observed sites. On the other hand, three-bond shifts are controlled by the hetero atoms existing in the pathway.
  • Haruhiko Yokoyama, Tomoko Ohta, Masayasu Iida
    1992 Volume 65 Issue 11 Pages 2901-2909
    Published: 1992
    Released: July 29, 2006
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    The conductivities for aqueous solutions of the chloride, bromide, iodide, nitrate, and perchlorate of the tris(ethylendiamine)cobalt(III) complex, [Co(en3)]3+, were measured with varying temperatures from 0 to 50 °C. The ion-association constants (KA) of the complex ion with the anions had minimum values at temperatures (tmin) characteristic of the salts. The values of tmin increased in the order Cl < Br < I < NO3 < ClO4. The order in magnitude of KA at 25 °C was ClO4 < NO3 < I < Cl < Br, but was somewhat dependent on the temperature. Both the KA and tmin values for the halides of [Co(en)3]3+ were larger than those of the hexaamminecobalt(III) complex, [Co(NH3)6]3+; the difference in KA was greatest for the iodide. The entropy and enthalpy changes in the ion association of [Co(en)3]3+ with the halide ions were smaller than those of [Co(NH3)6]3+. These results suggested that the hydration of [Co(en)3]3+ was relatively weak and its hydration water molecules in the vicinity of the methylene groups could be more easily substituted by the structure-breaker anions, compared with the water molecules around the amino groups. The KA and tmin values for the nitrate and perchlorate of [Co(en)3]3+ were smaller than those of [Co(NH3)6]3+, and both the entropy and enthalpy changes of ion association for the former salts were more positive. This was attributed to the decrease in the fraction of the contact ion pairs formed by the hydrogen bonding between the polar hydrogen atoms of the complexes and the oxygen atoms of the anions.
  • Satoshi Kawata, Hiroshi Kosugi, Hisashi Uda, Masamoto Iwaizumi, Hirosh ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 2910-2921
    Published: 1992
    Released: July 29, 2006
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    Dinuclear copper(II) complexes of 2-hydroxy-1,3-diaminopropane-, 2-hydroxy-1,4-diaminobutane-, and 3-hydroxy-1,5-diaminopentane-N,N,N′,N′-tetraacetic acids (AC3O, AC4O, and AC5O) have been investigated by potentiometric titration, EPR and other spectroscopies. It has been confirmed that two or three different kinds of dinuclear complex species are formed in every ligand system, depending on the pH. In the complexes formed in the low-pH region, the two copper ions are coordinated independently by the two iminocarboxyl groups and have a weak magnetic dipolar interaction. In all of the three ligand systems the dinuclear complexes deprotonate the alcohol OH groups at low pH values (below 6) to form μ-alkoxo between the two copper ions. For AC3O and AC4O systems, the formation of μ-alkoxo and μ-hydroxo-double bridged complexes follows as the pH increases, while the AC5O system forms a double-bridged complex at a step from the non-bridged complex at pH 5.8. These mono-μ-alkoxo bridged and double-bridged complexes have fairly strong spin exchange interactions between the paramagnetic centers through the bridges. The length of the methylene linkage plays a role in determining the complex structures and magnetic interactions between the paramagnetic centers.
  • Tadashi Hanaya, Hiroshi Yamamoto, Heizan Kawamoto, Margaret-Ann Armour ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 2922-2925
    Published: 1992
    Released: July 29, 2006
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    3-O-Benzyl-1,2-O-isopropylidene-6-O-tosyl-α-D-allofuranose was led to methyl (5R and 5S)-3-O-benzyl-5,6-dideoxy-5-[(methoxy)phenylphosphinyl]-D-ribo-hexofuranoside (9) in a 4 step sequence (55% overall yield). Methyl (5R and 5S)-2-acetamido-2,5,6-trideoxy-5-[(methoxy)phenylphosphinyl]-D-arabino-hexofuranoside (12) was prepared from 9 in 4 steps involving a C-2 inversion (62% overall yield). Compound 12 was then converted, in 2 steps, into the title compound, which was characterized as the peracetyl derivatives.
  • Minoru Hirota, Masahiro Nakada
    1992 Volume 65 Issue 11 Pages 2926-2933
    Published: 1992
    Released: July 29, 2006
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    Polychloro- and polybromobenzenes were photolyzed in acetonitrile and perfluorohexane. Photolyses of polychlorobenzenes in acetonitrile gave isomerized products in addition to dechlorinated products, which appeared exclusively in the photolyses in hexane and other solvents carrying hydrogen atoms active to hydrogen abstraction. The photolyses in perfluorohexane gave isomerized products to a lesser extent. The reaction in this solvent gave predominantly polyhalobiphenyls which are assumed to be produced through coupling.
    Without exception the isomerized products have the structure which can be expected to be formed via 1,3-migration of chlorine atom, though it is not sure at present whether it takes place actually. The isomerization was shown to proceed intramolecularly. Some evidence and theoretical rationalization in favor of the 1,3-chlorine migration mechanism are given.
  • Yoshiharu Nakano, Seiji Niki, Shigetoshi Kinouchi, Hiroshi Miyamae, Mi ...
    1992 Volume 65 Issue 11 Pages 2934-2939
    Published: 1992
    Released: July 29, 2006
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    The condensation reaction of malononitrile with acetone was catalyzed by variously pretreated alumina (1/4 equiv based on the amount of KF) to give a 2-azabicyclo[2.2.2]octane derivative in water (in more than 90% yield). With more catalyst (1 equiv), a potassium salt of the product was formed unexpectedly. Both products released isobutylene to give the corresponding pyridine derivatives.
  • Hitoshi Takeshita, Ying-She Cui, Nobuo Kato, Akira Mori, Yoshiaki Naga ...
    1992 Volume 65 Issue 11 Pages 2940-2947
    Published: 1992
    Released: July 29, 2006
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    2-Alkenyl-6-methyl-4H-1,3-dioxin-4-ones, adducts of diketene to alkenals or alkenones, are useful synthons which are applicable to photocycloadditions to construct multiply-functionalized alicyclic compounds via stereoselective intramolecular path. Some of the cage-shaped photoproducts showed extraordinary spectroscopic features.
  • Tadamitsu Sakurai, Akihide Kageyama, Hisayoshi Hayashi, Hiroyasu Inoue
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 2948-2954
    Published: 1992
    Released: July 29, 2006
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    The reaction of α-chymotrypsin (ChT) with bromomethyl 1-naphthyl ketone (1-BNK) or with bromomethyl 2-naphthyl ketone (2-BNK) took place at the active site causing inactivation of the enzyme according to second-order kinetics. In addition to this finding, a comparison of the absorption spectrum of 2-BNK-modified ChT (2-BNK–ChT) with those of native ChT and the model dimethyl(2-naphthoylmethyl)sulfonium bromide (2-NSS) at low pH revealed that the alkylating agent, BNK, reacts with methionine-192 on ChT in a 1 : 1 stoichiometric ratio. Evidence for the existence of BNK-derived reporter groups at the enzyme active site came from the observation of (1) positive induced circular dichroism bands of these groups and of (2) pronounced absorption spectral changes of the 2-BNK–derived pendant on denaturation of the alkylated enzyme with guanidine hydrochloride at pH 7.0. From the pH dependence of the absorption spectra of the modified enzymes and the model sulfonium salts, we determined the pKa values of 1-BNK–ChT, 1-NSS, 2-BNK–ChT, and 2-NSS to be 6.6, 7.5, 5.2, and 8.4 at 25 ± 1 °C, respectively. The much larger difference in pKa between 2-BNK–ChT and 2-NSS (ΔpKa = 3.2) compared with that between 1-BNK–ChT and 1-NSS (ΔpKa = 0.9) was explained in terms of stabilization of the 2-BNK-derived ylide pendant due to a configurationally rigid hydrogen-bonding interaction between the ylide carbonyl oxygen atom with a negative charge and the serine hydroxyl group located near the substrate binding site of ChT. Supporting evidence for this interpretation was obtained from solvent effects on the absorption spectra of model compounds as well as pH effects on the remaining activity of the alkylated enzymes.
  • Michio Higashijima, Shigeo Nishimura
    1992 Volume 65 Issue 11 Pages 2955-2959
    Published: 1992
    Released: July 29, 2006
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    The catalytic hydrogenation of phenol and cresols (methylphenols) with commercial Pd on active carbon (Pd–C) and acid-treated Pd–C (Pd–C–A) has been studied kinetically in t-pentyl alcohol (t-PeOH) and cyclohexane as solvents under 5.0 MPa hydrogen pressure at 120 °C. With both of the catalysts the maximum yields of the cyclohexanone intermediates as well as the hydrogenation rates of the phenols decreased markedly in t-PeOH, compared with hydrogenation in cyclohexane. With Pd–C–A in t-PeOH the decrease in the yields of cyclo-hexanone intermediates was shown to be due only to the increase in the relative reactivity of the cyclohexanones to phenols (K). On the other hand, with Pd–C the marked decreases were attributed not only to the increases in the values of K but also to the decreases in the selectivity for the formation of the ketone intermediates (f). The rates decreased in the order phenol > m- > p- > o-cresol, irrespective of the catalysts and solvents. The relative reactivities and strengths of the adsorption of phenol to isomeric cresols were evaluated by both individual and competitive hydrogenation. It is suggested that the phenols are adsorbed on the catalysts both at the benzene nucleus and the hydroxyl group, and that the remarkable effects of alcoholic solvents over basic Pd–C result from the interaction of the hydroxyl groups as phenoxide ions with alcoholic solvents which may weaken adsorption at the phenoxide ions.
  • Michio Higashijima, Hó Soc Man, Shigeo Nishimura
    1992 Volume 65 Issue 11 Pages 2960-2965
    Published: 1992
    Released: July 29, 2006
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    Three isomeric cyclooctadienes (1,5-, 1,4-, and 1,3-COD) were hydrogenated with phenylacetaldehyde (PAA)- or carbon monoxide (CO)-treated palladium black in tetrahydrofuran at 25 °C and atmospheric pressure of hydrogen. A complete depression of the hydrogenation of cyclooctene (COE) to cyclooctane (COA) was attained with both of the poisoned catalysts. By PAA the hydrogenation of 1,5-COD to COE was not hindered and the isomerization of 1,5-COD to 1,4-COD was greatly promoted, while the rate of hydrogenation of 1,4- and 1,3-COD decreased in the presence of PAA. By CO the hydrogenation and isomerization of 1,5-COD, as well as the hydrogenation of 1,4- and 1,3-COD, was suppressed. In the hydrogenation of 1,5-COD the PAA-treated palladium was more active and selective than was the CO-treated palladium for the formation of COE. The differences in the effects of these catalyst poisons are discussed on the basis of kinetic data concerning the individual and competitive hydrogenation of the three isomeric cyclooctadienes.
  • Tsuyoshi Satoh, Shigeyasu Motohashi, Norio Tokutake, Koji Yamakawa
    1992 Volume 65 Issue 11 Pages 2966-2973
    Published: 1992
    Released: July 29, 2006
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    Reaction of the carbanion derived from 1-chloroalkyl aryl sulfoxides with enones gave 1,2-adducts in good yields. Treatment of the adduct with potassium benzenethiolate afforded α-phenylthio β,γ-unsaturated carbonyl compound through an α,β-epoxy sulfoxide. Oxidation of the sulfide with 2.1 equivalents of m-chloroperbenzoic acid gave α,β-unsaturated γ-phenylsulfinyloxy carbonyl compound via sulfoxide-sulfenate rearrangement. The sulfinate was easily hydrolyzed with aqueous potassium hydroxide to afford α,β-unsaturated γ-hydroxy carbonyl compound in good yield. When optically active (−)-1-chloroalkyl p-tolyl sulfoxides were used in this procedure, a synthesis of optically active α,β-unsaturated γ-hydroxy carbonyl compounds with moderate to good optical purity was realized.
  • Masaya Nakata, Tomomasa Osumi, Ari Ueno, Takenori Kimura, Tetsuro Tama ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 2974-2991
    Published: 1992
    Released: July 29, 2006
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    The first total synthesis of herbimycin A (1), the benzoquinonoid ansamycin antibiotic, is described. (2E,4S,5R,6S,8S)-5,6-Dimethoxy-9-(4-methoxybenzyl)oxy-2,4,8-trimethyl-2-nonenal (40), corresponding to the C7–C15 portion of the ansa-chain of 1, was prepared from methyl 3,4-anhydro-2-deoxy-2-C-methyl-6-O-(triphenylmethyl)-α-D-altropyranoside (16), which had been previously prepared from methyl α-D-mannopyranoside according to our developed procedure, by using a regioselective epoxide opening [bis(1,2-dimethylpropyl)borane–NaBH4] and a stereoselective hydroboration (BH3·SMe2) as the key steps. This aldehyde 40 was subjected to the Brown’s diastereo- and enantioselective allylation conditions [[(Z)-3-methoxyallyl]diisopinocampheylborane] to afford the desired syn 3-methoxy-1,5-dodecadien-4-ol derivative. Subsequent three-step conversion of this alcohol furnished the synthesis of the C5–C15 ansa-chain aldehyde, (2S,4S,5R,6S,7E,9S,10S)-9-[(t-butyldimethylsilyl)oxy]-4,5,10-trimethoxy-2,6,8-trimethyl-7,11-dodecadienal (7). Union of 7 and the lithiated aromatic chromophore, prepared from N-(triphenylmethyl)-3-bromo-2,5-dimethoxyaniline and butyllithium, provided the coupling product, which was transformed to herbimycin A (1) through elongation of the C1–C4 carbon unit and macrolactamization. This fully enantiospecific synthesis elucidates the absolute stereochemistry of 1.
  • Satoshi Minakata, Shinobu Itoh, Mitsuo Komatsu, Yoshiki Ohshiro
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 2992-2997
    Published: 1992
    Released: July 29, 2006
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    Functionalization of 1H-pyrrolo[2,3-b]pyridine (7-azaindole) was studied to provide new compounds directing toward agrochemicals and/or functional materials. Amino groups such as NH2, NH(CH2)2NH2, and NH(CH2)2NH(CH2)2NH2 were introduced onto 6-position of 7-azaindole to form multidentate agents. 6-Amino and 6-iodo derivatives were easily converted to podant-type compounds, N,N′-bis(1H-pyrrolo[2,3-b]pyridin-6-yl)-1,3-benzenedicarboxamide and bis(1H-pyrrolo[2,3-b]pyridin-6-yl)acetylene, respectively. Polyacetylene having 1H-pyrrolo[2,3-b]pyridyl group as a pendant was obtained by polymerization of 6-ethynyl-7-azaindole synthesized by ethynylation of 6-bromo derivative. As functionalization at 3-position of 7-azaindole, syntheses of 3,3′-selenobis[1H-pyrrolo[2,3-b]pyridine] and the corresponding 3,3′-thio compound, as well as 3-carboxyethenyl- and 3-vinyl-7-azaindoles were performed. Some of these products exhibited high fungicidal activity.
  • Toshikazu Ibata, Hiroyuki Suga, Yasushi Isogami, Hatsue Tamura, Xiaola ...
    1992 Volume 65 Issue 11 Pages 2998-3007
    Published: 1992
    Released: July 29, 2006
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    The reaction of substituted oxazoles with 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione (PTAD) or diethyl azodicarboxylate gave the corresponding 1,2,4-triazoline derivatives through formal [3+2] cycloaddition accompanying ring opening of oxazoles. The molecular structure of an adduct of 5-methoxy-4-methyl-2-(p-tolyl)oxazole with PTAD was determined by means of X-ray crystallography.
  • Yoshio Hori, Osamu Koga, Akiko Aramata, Michio Enyo
    1992 Volume 65 Issue 11 Pages 3008-3010
    Published: 1992
    Released: July 29, 2006
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    A nickel electrode surface during electroreduction of CO2 in phosphate buffer solution was studied by in situ infrared spectroscopy. SNIFTIRS (subtractively normalized interfacial Fourier transform infrared spectroscopy) technique showed the presence of adsorbed CO on the electrode surface between −0.4 and −0.8 V vs. NHE in CO saturated solution. The adsorbed CO was bonded to the electrode in linear and bridged fashions. Linear and bridged adsorbed CO molecules were also detected on the electrode during the electroreduction of CO2. Linear CO disappeared at relatively negative potential (−0.8 V). Since the reduction of adsorbed CO proceeds below −1.0 V, the electroactive species in the reduction of CO is presumed to be bridged type CO.
  • Hiroshi Kodama
    1992 Volume 65 Issue 11 Pages 3011-3014
    Published: 1992
    Released: July 29, 2006
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    α-Bi2O3 is a candidate material for the immobilization of radioactive iodine. The present paper discusses a method for removing radioactive iodide ion by fixing it into α-Bi5IO7 by a direct reaction with α-Bi2O3; it also reports on experimental conditions under which aqueous iodide reacts with α-Bi2O3 to form a single phase of α-Bi5IO7. α-Bi2O3 was reacted with aqueous iodide in LiI, NaI, KI, and NH4I solutions. Although a previous paper reported that the concentration of aqueous iodide ion was the most important factor to form a single phase of α-Bi5IO7, the present result shows that it is not an important factor. The α-Bi5IO7 single phase can be obtained regardless of the concentration of iodide ion when the ratio of the gram molecular number of the bismuth oxide and the gram ion number of the radioactive iodide ion is adjusted in the range 5 : 2 to 1 : 2 in a LiI solution, 4 : 1 to 1 : 2 in a NaI solution, and 4 : 1 to 1 : 4 in a KI solution. A reaction in a NH4I solution does not produce a single phase of Bi5IO7 at any ratio.
  • Ken-ichi Okamoto, Yuko Watanabe, Takumi Konno, Jinsai Hidaka
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3015-3021
    Published: 1992
    Released: July 29, 2006
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    The novel T-cage-type Se-bridged polynuclear complexes with 2-aminoethaneselenolate (aese), [{Co(aese)3}4Zn3Cl]5+, [{Co(aese)3}4Zn4O]6+, and [{Rh(aese)3}4Zn4O]6+, have been synthesized. Of these complexes, the spontaneous resolution was recognized for [{Co(aese)3}4Zn4O]Cl6 and [{Rh(aese)3}4Zn4O](NO3)6 with a “complete” [Zn4O]6+ core. The crystal structure of -[{Co(aese)3}4Zn4O](ClO4)6·4H2O was determined by the X-ray diffraction method. The crystal is cubic, space group P213, a = 19.646(2) Å, U = 7582.2(7) Å3, Z = 4, and R = 0.0725. The four octahedral fac(Se)-[Co(aese)3] subunits are bound to the tetrahedral [Zn4O]6+ core in a tetrahedral arrangement, giving an approximate T symmetrical (T-cage-type) structure. The three Se atoms in each fac(Se)-[Co(aese)3] subunit are bound to the three different Zn atoms. For the isomer, the chiral configurations are regulated to Δ for all four fac(Se)-[Co(aese)3] subunits, and S for all 12 bridging Se atoms. The electronic absorption and CD spectral behavior of the complexes are discussed in comparison with those of the related mononuclear and linear-type trinuclear complexes, and the corresponding T-cage-type S-bridged polynuclear complexes.
  • Masayuki Harada, Yasuhiko Fujii, Satoshi Sakamaki, Hiroshi Tomiyasu
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3022-3026
    Published: 1992
    Released: July 29, 2006
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    Kinetics of the fluoride exchange in uranium(VI) (uranyl) fluoro complex was studied by using 19F NMR. The 19F NMR signal of coordinated fluoride at the equatorial positions of uranyl ion was first observed at about 80 ppm down field from that of bulk F. From area measurements of the coordinated and free 19F NMR signals, penta-fluoro complex UO2F53− was confirmed to exist in aqueous solutions containing high concentration of fluoride ion. The stability constant K5 = [UO2F53−]/[UO2F42−][F] was determined to be 1.31 mol−1 kg. The rate of F exchange between coordinated and bulk F was measured by the 19F NMR line-broadening method and the observed first-order rate constant kobsd was expressed as Kobsd = (k4 + k5K5[F])[F]/(1 + k5[F]) where k4 and k5 are the exchange rate constants of F between bulk and coordinated F in UO2F42− and UO2F53−, respectively. The associative or associative interchange mechanism was proposed from the experimental results.
  • Katsuma Hiraki, Yoshio Fuchita, Hirosuke Kawabata, Koji Iwamoto, Takas ...
    1992 Volume 65 Issue 11 Pages 3027-3032
    Published: 1992
    Released: July 29, 2006
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    [RuClH(CO)(PPh3)3] (1) reacted with alkyl allyl sulfides at 10–25 °C to give insertion products, [Ru(CH2CH2CH2SR)Cl(CO)(PPh3)2] (R = CH3, 2; R = CH2C6H5, 3; and R = CH2CH=CH2, 4). Complexes 24 exhibited temperature-dependent NMR spectra above −40 °C, indicating that rapid exchange occurred between two structural isomers owing to inversion of the alkyl group upon the coordinated sulfur stom. Upon heating at 67 °C, 2 was converted into a binuclear complex, [Ru2(μ-Cl)Cl(μ-H)(μ-SCH3)(CO)2(PPh3)3], evolving propylene. Complex [RuClH(CO)(dppe)(PPh3)] (7) [dppe = 1,2-bis(diphenylphosphino)ethane] reacted with allyl methyl sulfide at 110 °C to afford [Ru2Cl2(μ-SMe)2(CO)2(dppe)2] (8), evolving propylene.
  • Saeko Kurachi, Shigeru Ohba
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3033-3041
    Published: 1992
    Released: July 29, 2006
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    Crystal structures of octahedral cobalt(III) complexes containing diamines, NH2 (CH2)n NH2 with n = 3 or 4 (abbreviations are tn and tmd, respectively), were determined by X-ray analysis. In crystals of [Co(tn)(tmd)2] Cl3, (1), the tn chelate ring takes skew-boat form, and the conformation of the complex is lel lel2. In crystals of [Co(tn)2(tmd)]Br3·2.7H2O, (2), both two independent complex cations take syn-chair2 lel configuration. Molecular mechanics calculation indicated that the six-membered tn chelate ring may take skew-boat form in a crowded system to reduce the steric repulsions between the chelate rings, although the tn chelate ring originally prefers the chair form.
  • Masakazu Kita, Masaaki Okuno, Kazuo Kashiwabara, Junnosuke Fujita
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3042-3048
    Published: 1992
    Released: July 29, 2006
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    The [Co(dtc)3−n(dmope)n]n+ (n = 1, 2) complexes were prepared, where dtc and dmope denote a dimethyldithiocarbamate ion and 1,2-bis(dimethoxyphosphino)ethane, respectively. The absorption and magnetic circular dichroism (MCD) spectra, and reduction and oxidation potentials were compared with those of the corresponding 1,2-bis(dimethylphosphino)ethane (dmpe) and related complexes. The molecular structures of [Co(dtc)(dmope)2](BF4)2 (1) and [Co(dtc)(dmpe)2] (BF4)2 (2) were determined by the X-ray diffraction method. Crystal data are; for 1, monoclinic, Cc, a = 18.154(5), b = 12.533(2), c = 14.447(3) Å, β = 101.69(2)°, V = 3219(1) Å3, Dx = 1.61, Dm = 1.60(3) g cm−3, and Z = 4, R = 0.044 for 3259 reflections; for 2, monoclinic, P21/a, a = 18.967(3), b = 10.333(1), c = 14.459(2) Å, β = 90.10(2)°, V = 2833.8(7) Å3, Dx = 1.53, Dm = 1.54(4) g cm−3, Z = 4, R = 0.052 for 5662 reflections. The average Co–P bond distance trans to S is 2.186(2) Å for 1 and 2.240(1) Å for 2, and that trans to P is 2.226(2) Å for 1 and 2.278(1) Å for 2. The Co–P distances in 1 are shorter by ca. 0.05 Å than those in 2, while the average Co–S bond distances are similar, 2.288(1) Å for 1 and 2.282(3) Å for 2.
  • Yasuko Kamochi, Tadahiro Kudo
    1992 Volume 65 Issue 11 Pages 3049-3054
    Published: 1992
    Released: July 29, 2006
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    Aromatic and aliphatic carboxylic acids were rapidly reduced with samarium diiodide by the addition of base in the presence of protic solvent at room temperature to the corresponding alcohols. Sodium benzoate was similarly reduced with samarium diiodide in the presence of H2O in a good yield. In the similar reactions of benzoic acid derivatives bearing carboxyl, formyl, carbamoyl, methoxyl, and chloro groups, these functional groups were also reduced to the corresponding alcohol or amine derivatives. Interestingly, the carboxyl and formyl groups of benzoic acids were partly reduced into the methyl group.
  • Hironobu Hojo, Saburo Aimoto
    1992 Volume 65 Issue 11 Pages 3055-3063
    Published: 1992
    Released: July 29, 2006
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    Using partially protected peptide thioesters as building blocks, we synthesized HU-type DNA-binding protein of Bacillus stearothermophilus. Four peptide segments, Boc–[Lys(Boc)3]–HBs(1–15)–SCH2CH2CONH2, iNoc–[Lys(Boc)18,19,23,38]–HBs(16–39)–SCH2CH2CONH2, iNoc–[Lys(Boc)41,59]–HBs(40–60)–SCH2CH2CONH2, [Lys(Boc)75,80,83,86,90]–HBs(61–90) were prepared using peptides obtained by a solid-phase method. A partially protected peptide thioester was condensed to a peptide with a free amino group by converting the thioester to the corresponding active ester in the presence of silver ions and N-hydroxysuccinimide. Finally, highly pure synthetic HBs(1–90) was obtained.
  • Shigeru Nishiyama, Tomio Inagaki, Shosuke Yamamura, Koji Hasegawa, Jun ...
    1992 Volume 65 Issue 11 Pages 3064-3067
    Published: 1992
    Released: July 29, 2006
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    Related to raphanusanins, light-induced growth inhibitors of radish seedlings, syntheses of trans- and cis-3-methoxy-4-methylthio-2-piperidinethiones provided the structural revision of the natural products. During syntheses of several piperidinethione derivatives, the dihydropyridinethione derivative was found to possess twentyfold stronger inhibitory activity than the natural products.
  • Akira Sera, Toshihiro Tsuzuki, Eishi Satoh, Kuniaki Itoh
    1992 Volume 65 Issue 11 Pages 3068-3071
    Published: 1992
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    The reaction of substituted dicyanoalkenes with aqueous titanium(III) chloride was examined. The dicyanoalkenes, which showed irreversible reduction characteristics on cyclic voltammograms, (typically, 2-cyano-3-phenylpropenenitrile), afforded cyclized and/or uncyclized hydrodimers, while those characterized by reversible reduction behavior, (typically, 2-cyano-3,3-diphenylpropenenitrile), yielded the corresponding saturated dinitriles. The reduction mechanism has been rationalized by taking account of the electron transfer from the Ti(III) species to the dicyanoalkenes, followed by protonation, or dimerization and cyclization.
  • Mizue Fujio, Naomi Goto, Tetsuro Dairokuno, Mutsuo Goto, Yoshihiro Sae ...
    1992 Volume 65 Issue 11 Pages 3072-3079
    Published: 1992
    Released: July 29, 2006
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    The solvolysis rates of threo-2-aryl-1-methylpropyl brosylates were determined for a series of substituents in acetic acid and 80% aq ethanol. The nonlinear substituent effect on the total rate was dissected with excellent precision into two linear LArSR relationships, each for the aryl-assisted (FkΔ) and unassisted (ks) processes. The use of the Brown σ+ for the dissection of the kΔ-correlation of this system failed to give any satisfactory results. The intermediate resonance demand of the kΔ solvolyses must be far beyond the scope of the Brown σ+ treatment with a fixed resonance demand of unity. The ρΔ and rΔ values for the kΔ process of thero-2-aryl-1-methylpropyl solvolysis were given to be −3.36 and 0.56 in AcOH, and −3.71 and 0.54 in 80% aq EtOH, respectively; they were identical to those for other aryl-assisted solvolyses, such as the neophyl system. Regardless of the structures of the reaction site, the resonance demands of β-aryl-assisted solvolysis of an identical mechanism all fall within a narrow range of 0.5–0.6 in the r scale of the continuous spectrum of resonance demands in aryl-conjugating carbocation solvolyses. The resonance demand of the aryl-assisted kΔ mechanism can be characterized in terms of this intermediate r value.
  • Hitoshi Mazaki, Tadashi Watanabe, Terumi Takahashi, Andreas Struck, Hu ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3080-3087
    Published: 1992
    Released: July 29, 2006
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    Kinetic and equilibrium features of the epimerization in six C132-epimer pairs of chlorophyllous pigments, namely chlorophyll (Chl) a/a′, Chl b/b′, pheophytin (Pheo) a/a′, Pheo b/b′, C20-chlorinated Chl (Cl–Chl) a/a′, and Cl–Pheo a/a′, catalyzed by bases (triethylamine, pyrrolidine, and piperidine) and by Lewis acids (magnesium acetylacetonate and magnesium chloride), have been studied in diethyl ether and methanol. A significant difference was noted in the epimerization rate and equilibrium epimeric composition among the pigment systems. The difference in the rate constants was rationalized in terms of the ease in C132-proton detachment, affected by the ring π-electron density which in turn depends on the electron donation or withdrawal by the central metal and/or ring substituents. For Lewis acid-catalysis, a dominant factor appears to be the stabilization of the C131-enolate anion via formation of a loose complex with extraneous Mg2+. A synergistic action of a base (triethylamine) and a Lewis acid (Mg2+) was observed for the epimerization or enolization of Pheo a/a′ in methanol.
  • Toshikazu Ibata, Hirofumi Nakano
    1992 Volume 65 Issue 11 Pages 3088-3093
    Published: 1992
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    The rhodium(II) acetate-catalyzed reaction of various α-diazocarbonyl compounds with alkyl, phenyl, and benzoyl isothiocyanates gave 2-imino-1,3-oxathioles in good yields. 2(3H)-Oxazolethione was obtained as a by- product only in the reaction of diazodimedone with methyl isothiocyanate. The mechanism through thiocarbonyl ylide and azomethine ylide was proposed for these reactions, and preferable formation of thiocarbonyl ylide was explained by heat of formation and frontier molecular orbital calculations.
  • Yukito Murakami, Yoshio Hisaeda, Hiroshi Kohno, Teruhisa Ohno, Takuya ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3094-3102
    Published: 1992
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    Hydrophobic vitamin B12 derivatives bearing a chiral binaphthyl moiety, hexamethyl 71-decarboxy-71-[(R)-2′-methoxy-1,1′-binaphthyl-2-carboxymethyl]cobyrinate perchlorate [B12–BINAP(R)] and hexamethyl 71-decarboxy-71-[(S)-2′-methoxy-1,1′-binaphtyl-2-carboxymethyl]cobyrinate perchlorate [B12–BINAP(S)], were prepared from cyanocobalamin. These complexes were characterized by means of electronic and circular dichroism spectroscopy as well as by cyclic voltammetry in comparison with those data for a hydrophobic vitamin B12 without a binaphthyl moiety. The enantioselective alkylation of hydrophobic vitamin B12 derivatives at the β-axial site was examined in methanol with various 3-bromo-2-methylpropionic esters by means of 1H NMR spectroscopy. All the hydrophobic vitamin B12 derivatives used here, the one bearing methoxycarbonyl groups as peripheral substituents without a binaphthyl moiety, B12–BINAP(R), and B12-BINAP(S), were found to bind (S)-2-methylpropionates more favorably than the corresponding R-enantiomers; the highest S-selectivity was observed with the latter two derivatives, 65% e.e. The cause of such S-enantioselectivity was discussed with attention to stereochemical configurations of the peripheral substituents placed in the corrin ring.
  • Hiroshi Sasaki, Setsuo Kobayashi, Kishiroo Iwasaki, Shuichi Ohara, Tet ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3103-3107
    Published: 1992
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    The thermal stability of intramolecular coupling products from three kinds of p-xylylenebis(anthrylcarboxylate)s are evaluated. Upon near-UV irradiation, two anthracene moieties in each derivative react at the 9–9′ and 10–10′ positions. The derivatives then from intramolecular coupling products. These coupling products are identified by means of 1H NMR and a linear combination of the atomic orbital coefficients for the highest occupied molecular orbital and the lowest unoccupied molecular orbital from analogues of each derivative. After keeping for 1000 h at a temperature of 60 °C, the coupling products from 2 species of p-xylylenebis(anthrylcarboxylate)s do not revert to the original p-xylylenebis(anthrylcarboxylate)s and are thermostable. However, these thermostable coupling products are reversed to the p-xylylenebis(anthrylcarboxylate)s by UV (260 nm) irradiation. The thermal stability of these coupling products can be explained on the basis of the magnitude of the relative distortion energy.
  • Masafumi Yoshida, Noriyuki Sakamoto, Kimiyoshi Ikemi, Shizuo Arichi
    1992 Volume 65 Issue 11 Pages 3108-3111
    Published: 1992
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    The conformation of poly(4-vinylpyridine) (P4VP) in aqueous solutions of sulfuric acid was studied by light scattering and viscosity measurements at 25 °C. Comparing the experimental intramolecular particle scattering factor (P(θ)) and Debye’s theory, it was confirmed that in the Θ-state where the apparent second virial coefficient is zero, the conformation of P4VP is characterized as a Gaussian chain. The intrinsic viscosities of P4VP in aqueous solutions of sulfuric acid of various concentrations were analyzed according to the theoretical equation of Tanaka. The value of the characteristic ratio (C) increased with increasing H2SO4 concentration.
  • Shunzo Yamamoto, Minoru Suzuki, Yoshimi Sueishi, Norio Nishimura, Yo-i ...
    1992 Volume 65 Issue 11 Pages 3112-3117
    Published: 1992
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    The thermal decomposition of γ-butyrolactone was studied in a static system at temperatures from 690 to 833 K and pressures from 70 to 4300 Pa. The major products were CO, CO2, ethylene, propylene, and cyclopropane. The first-order rate constant for the apparently homogeneous formation of CO is described in terms of Arrhenius parameters log A (s−1) = 16.44 ± 0.04 and Ea = 310.0 ± 4.2 kJ mol−1. Under the same conditions the ratio of CO2/CO increased with decreasing temperature, corresponding to an activation energy of about 294 kJ mol−1 for CO2 formation and a frequency factor of about 60-times lower than that for CO formation. The decomposition induced by a pulsed CO2 laser was also studied; the same decomposition products were observed and the dependences of their yields on the fluence were examined.
  • Yoshimi Sueishi, Masahiro Kuzukawa, Shunzo Yamamoto, Norio Nishimura
    1992 Volume 65 Issue 11 Pages 3118-3121
    Published: 1992
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    The rate constants (kex) for the spin exchange of various types of nitroxides were determined from the concentration dependence of the ESR line-broadening. The exchange integral (J) and the steric factor (fs) for the spin exchange were estimated from the pressure dependence of kex. The estimated J-values are about 1011 s−1 and are almost independent of the radical species. For nitroxides having –OH or –NH2 in acetone and nitroxides having long-chain in acetone and toluene, the fs-values are about 0.3, while for other nitroxides in hexane and pentane, the fs-values are about 0.5. The results are discussed in terms of the solute–solvent interaction as well as the steric effect.
  • Kazuhiko Honda, Kazuo Kitaura, Kichisuke Nishimoto
    1992 Volume 65 Issue 11 Pages 3122-3134
    Published: 1992
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    Monte Carlo (MC) simulations for liquid hydrogen fluoride (HF) were carried out using a new type of intermolecular potential function. The bonding energy distribution function was found to have three peaks corresponding to the distributions of molecules which have one, two, and three hydrogen bonds with neighbors. A partition function of liquid HF was derived referring to the results of MC simulations, where a simple Hamiltonian consisting of harmonic oscillators and hydrogen bond energies was employed. The thermodynamic properties calculated by the partition function reasonably reproduced the experimental data. Moreover, the effects of hydrogen bondings on various thermodynamic properties were revealed based on the partition function.
  • Michio Kobayashi, Yoshinori Kato, Norio Koma, Naobumi Taki, Kazunori M ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3135-3140
    Published: 1992
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    Polarized electronic absorption spectra of a nematic liquid crystal (4-butyl-4′-ethoxyazobenzene, BEAB) were measured in sandwich-type cells to which no rubbing treatment was applied. These polarized spectra were utilized to evaluate the mean squares of the direction cosines of the transition moment, those of the molecular orientation axis, and the three-dimensional absorption components as a function of the cell gap. It has been shown that the inclinations of the transition moment for the 354 nm band (long-axis polarized) and the molecular orientation axis to the cell plane increase with the decrease in the cell gap while the absorption component for the 354 nm band normal to the cell plane decreases. These observations provide a quantitative support for the molecular orientation model proposed previously that the molecular long axis tends to be oriented parallel to the cell plane in the interface region and perpendicular in the bulk region. The thickness of the interface region has been estimated to be about 0.02 μm by a model calculation based on a discrete model for the orientation of the BEAB molecules in the cell.
  • Kumao Hamanoue, Toshihiro Nakayama, Hideyuki Sasaki, Koichiro Ikenaga, ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3141-3148
    Published: 1992
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    In toluene and ethanol containing triethylamine (TEA), a reaction of the lowest excited triplet state [3AQ(T1)] of anthraquinone (AQ) with ground-state TEA gave rise to the formation of an exciplex [3(AQ–TEA)*] which converted into a contact ion pair between the AQ radical anion (AQ·) and the TEA radical cation (TEA+·). By an intramolecular proton transfer, this contact ion pair yielded anthrasemiquinone radical followed by the formation of 9,10-anthracenediol (AQH2); in ethanol, the monoanion (AQH) of AQH2 was also produced. In ethanol/TEA, moreover, not only the decay rate constant of 3(AQ–TEA)* but also the quantum yield for the photoreduction of AQ were affected by the change of TEA concentration. This was interpreted in terms of the existence of a rapid interconversion between 3(AQ–TEA)* and atriplex [3(AQ–TEA2)*] of 3AQ(T1) with ground-state TEA. In contrast to the exciplex formation in ethanol and toluene, free AQ· (and TEA+·) and 3(AQ–TEA)* [or a contact (or solvent-separated) ion pair between AQ· and TEA+·] were produced in acetonitrile via the second and lowest excited triplet states of AQ, respectively: In the submicrosecond time regime, 3(AQ–TEA)* or the contact (or solvent-separated) ion pair dissociated into the radical ions (AQ· and TEA+·) followed by their second-order reaction yielding finally AQH2 and AQH.
  • Yasushi Yamamoto, Shinji Kato, Hiroshi Yamashita, Takashi Maekawa
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3149-3152
    Published: 1992
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    The optical resolutions of phenylalanine and mandelic acid were performed by complex formation with Cu2+. D- and L-mandelic acids were completely resolved by forming a complex with L-phenylalanine, while the maximum optical purity of D- and L-phenylalanine by using D-mandelic acid was about 65%. The mole ratio of Cu2+ to phenylalanine and/or mandelic acid in the complexes was 0.5. These results were interpreted in terms of the relative stability of the complexes, i.e., the optical absorption energies in the aqueous media.
  • Tomozo Koh, Yasunobu Yonemura, Hiroaki Kanai
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3153-3156
    Published: 1992
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    A simple method for the determination of thiocyanate has been proposed, based on the oxidation of thiocyanate to sulfate with iodate in a sulfuric acid medium and on the spectrophotometric measurement of the iodine as triiodide at 350 nm, formed from the excess iodate with iodide added. The complete oxidation of thiocyanate to sulfate using iodate was achieved in a medium containing varying amounts of sulfuric acid at 30 °C. Thiocyanate reacted with iodate with a mole ratio of 1 : 1 under the conditions employed here. The proposed method is approximately 20-fold more sensitive than the conventional method using iron(III) and can be applied to the determination of thiocyanate in the concentration range 5.6 × 10−7−5.2 × 10−5 mol dm−3 (0.31–30.2 μg of SCN in 10 cm3). The relative standard deviation (n = 1) was 0.44% at the 3 × 10−5 mol dm−3 thiocyanate (17.4 μg of SCN in 10 cm3) level.
  • Tomoko Sotomatsu, Masao Shigemura, Yoshiyuki Murata, Toshio Fujita
    1992 Volume 65 Issue 11 Pages 3157-3162
    Published: 1992
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    The pKa values of 10 benzoic acids occupied simultaneously at the 2- and 6-positions by various substituent combinations were newly measured in water at 25 °C. The effects of the substituents were analyzed quantitatively with regression analysis and free-energy-related parameters of the Hammett–Taft type. The results were compared with those of the analysis of the pKa of mono-ortho-substituted acids cited in the literature. The resonance effect of substituents in di-ortho-substituted compounds was insignificant, but the electronic effect of the through-space inductive type in terms of the Charton σI and the steric effect in terms of the Taft–Kutter–Hansch Es were not. The overall effects were additive for two substituents. In mono-ortho-substituted acids, a “regular” electronic effect of ortho substituents similar to that of the corresponding para substituents including the resonance effect component was indicated to work in addition to the steric and the through-space inductive effects. The steric and through-space inductive effects of a substituent were almost unchanged regardless of whether the substituent was involved in mono- or di-ortho substitution. A possible rationale integrating the results for mono- and di-ortho-substituted acids was to assume an intermediate formation for the dissociation process in which the carboxyl group is partly ionized and more easily twisted than the nonionized carboxyl group in the initial state.
  • Koichi Shibata, Oyo Mitsunobu
    1992 Volume 65 Issue 11 Pages 3163-3173
    Published: 1992
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    The reactions of 2-(2-oxoalkylseleno)benzothiazoles with allylic Grignard reagents in the presence of BF3·OEt2 gave the corresponding 2-[(2-alkyl-2-hydroxy-4-pententyl or 2-alkyl-2-hydroxy-4-methyl-4-pentenyl)seleno]benzothiazoles which, on treatment with Ph3P and NaH, afforded 1,4-dienes in good to excellent yields.
  • Shiro Koseki, Akihiko Ishitani
    1992 Volume 65 Issue 11 Pages 3174-3176
    Published: 1992
    Released: July 29, 2006
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    SiH2Cl2 decomposition into SiCl2 and H2, SiCl2 insertions into NH3 and SiH4, and 1,1-HCl elimination from SiHCl2NH2, which seem to occur in chemical vapor deposition processes of the silicon-nitride film growth, were theoretically investigated using second-order Moller–Plesset perturbation theory based on ab initio restricted Hartree–Fock method. The calculated results suggest that the Cl atoms create an energy barrier larger in Si–Si bond formation and facilitate the growth of stoichiometrically better films.
  • Kenichi Nakabayashi, Setsuo Takamuku
    1992 Volume 65 Issue 11 Pages 3177-3179
    Published: 1992
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    The mechanism of valence isomerization between methyl 5-(4-biphenylyl) tetracyclo [3.2.0.2,70.4,6] heptane-1-carboxylate (1) and methyl 3-(4-biphenylyl)bicyclo[2.2.1]hepta-2,5-diene-2-carboxylate (2) under the triplet sensitization in benzene was studied by γ-radiolysis and pulse radiolysis. As an intermediate for the isomerization, an equilibrium state between a 1,3-biradical intermediate and a triplet state with the structure of norbornadiene has been estimated. The triplet energy levels of 1 and 2 were determined to be 59 and 57 kcal mol−1, respectively. The energy difference between the ground states of 1 and 2 was determined to be 18 kcal mol−1.
  • Takahiro Ueda, Nobuo Nakamura
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3180-3182
    Published: 1992
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    The crystal of 2,2′-[oxybis(ethyleneoxy)] diethanol (tetraethylene glycol or TEG) complex of sodium tetraphenylborate, [Na(C8H18O5)]B(C6H5)4, is triclinic, Pl, with the unit cell dimensions: a = 1.1730 (2), b = 1.3212 (3), c = 1.1408 (2) nm, α = 108.83 (1), β = 112.40 (1), and γ = 67.42° (2), Z = 2. This compound contains binucear metal complex, ion, [Na(C8H18O5)]22+ The sodium ion is coordinated highly asymmetrically by six oxygens in two TEG.
  • Yoshiharu Usui, Shigeharu Takebayashi, Manabu Takeuchi
    1992 Volume 65 Issue 11 Pages 3183-3185
    Published: 1992
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    Photochemical nitration of p-hydroxybenzoate, HBA, initiated by UV irradiation to sodium nitrate of sodium nitrite was observed in aqueous solutions. 4-Hydroxy-3-nitrobenzoate was formed, with maximum quantum yields of 0.007 and 0.09 for NaNO3 and NaNO2, respectively. From the dependence of the yields on the pH and concentrations of oxygen and OH-scavengers, we propose a mechanism involving the addition of OH· to the aromatic ring of HBA and electron abstraction NO2 by the OH· adduct for the photonitration.
  • Akito Ishida, Kazuki Yamamoto, Setsuo Takamuku
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3186-3188
    Published: 1992
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    Pulse radiolysis of 2-methylbenzophenone (MBP) in benzene gave the triplet excited state (3MBP*) which rapidly decayed by intramolecular hydrogen abstraction resulting in the photoenol. Successive laser flash photolysis elucidated the photochemical formation of dihydroanthrone from the photoenol.
  • Wasuke Mori, Shinnichiro Suzuki, Yasuo Nakao, Tsukasa Nishimura, Akio ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3189-3191
    Published: 1992
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    Mixed ligand dinuclear copper(II) complexes bridged by one deprotonated oximato and one hydroxo or two acetato were prepared and characterized according to their magnetic susceptibilities, electric conductivities, visible absorption spectra, and cyclic voltammograms. A very strong antiferromagnetic interaction between two copper(II) ions in hydroxo-bridged complexes has been observed (coupling constants J = −520 – −530 cm−1, H = −2JS1·S2). Two acetato-containing complexes comprise triply (one deprotonated oximato and two acetato) bridged coppers, which are characterized by J = −130 – −235 cm−1.
  • Emiko Kaneko, Hitoshi Hoshino, Takao Yotsuyanagi, Ritsuko Watabe, Tosh ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 11 Pages 3192-3194
    Published: 1992
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    An ion-pair reversed-phase partition high-performance liquid chromatography-spectrophotometric detection system with 2,2′-dihydroxyazobenzene has been successfully applied to the determination of μg dm−3 level of aluminium in natural waters. The detection limit is 0.2 μg dm−3 in pure solution, and 1 μg dm−3 for total aluminium in water sample. The relationship between the aluminium concentration and pH value of the ground waters is also discussed.
  • Wongsiri Sankhavasi, Keiki Kishikawa, Shigeo Kohmoto, Makoto Yamamoto, ...
    1992 Volume 65 Issue 11 Pages 3195-3197
    Published: 1992
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    A noncatalyzed conjugate addition reaction of alkylaluminium compounds to 1,3-dibenzyl-5-methylene-2,4-imidazolidinedione 1 led to the exclusive formation of single and double conjugate adducts (2 and 3, respectively). The ratio of 2 : 3 depended on the reaction temperature and the concentration of 1.
  • Yoshikazu Sugihara, Junji Saito, Ichiro Murata
    1992 Volume 65 Issue 11 Pages 3198-3199
    Published: 1992
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    1-Formyl-4-[2,4,6-cycloheptatrienyl)(phenylsulfinyl)methyl] azulene (8b) was thermolyzed at 65 °C for 100 min to give 7,12a-dihydro-2-formyldicyclohept[cd,g]indene (9b), which was isomerized to 1,10-dihydro-2-formyldicyclohept[cd,g]indene (10b), upon heating at the higher temperature.
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