Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 68 , Issue 11
Showing 1-37 articles out of 37 articles from the selected issue
  • Noboru Hirota, Keisuke Tominaga, Seigo Yamauchi
    1995 Volume 68 Issue 11 Pages 2997-3010
    Published: 1995
    Released: July 10, 2006
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    The results of Chemically Induced Dynamic Electron Polarization (CIDEP) studies of acetone in 2-propanol and triethylamine are reviewed to show how CIDEP studies can reveal interesting details of the initial processes of photochemical reactions. After a brief description of various mechanisms that give rise to CIDEP, the following topics are discussed: a) spectral pattern and the main reacting state, b) CIDEP mechanisms and the temperature and frequency dependences of the spectra, c) direct EPR observation of the radical pair spectra in solution, d) time-developments of the CIDEP signals and spin and reaction dynamics of the initial processes of photochemical reactions, e) quantitative analyses of the magnitudes of CIDEP in terms of a stochastic Liouville equation, and f) some related applications. An overview of the remaining problems and the future outlook is also presented.
  • Kazuhiro Tanaka, Masamichi Ito, Hidetoshi Kita, Ken-ichi Okamoto, Yasu ...
    1995 Volume 68 Issue 11 Pages 3011-3017
    Published: 1995
    Released: July 10, 2006
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    The effects of CO2-conditioning, i.e. exposing a polymer film to high pressure CO2 and degassing it in vacuo, on positron annihilation and gas permeation properties of polyimides and polyethylene were investigated. Both lifetime and intensity of ortho-positronium (o-Ps) (τ3 and I3, respectively) increased for polyimides by the CO2-conditioning. The size distribution of free space holes, which was evaluated from annihilation rate distribution of o-Ps, became broader and shifted to larger size. Permeability, diffusion, and solubility coefficients of gases for polyimides increased by the CO2-conditioning. The increases in diffusion coefficient are attributed to increases in volume fraction of free space holes, VF. The increases in τ3 and in I3 were much larger than those expected from the increases in VF. This may be explained by a model based on an interplay between electron affinity and size of free space holes for Ps formation. In the CO2-conditioned films, permeability and diffusion coefficients, VF, and I3 gradually decreased with lapse of time but after five months they were still larger than those in the as-cast films, whereas τ3 remained almost constant. No effect of the CO2-conditioning was observed for polyethylene.
  • Reza Islampour, Soheila Gharanfoli
    1995 Volume 68 Issue 11 Pages 3019-3026
    Published: 1995
    Released: July 10, 2006
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    A general formulation of the nonradiative decay-rate constant of initially selected vibronic states in polyatomic molecules is developed. This method includes the effects of displacements as well as distortions of the potential-energy surfaces. The rate constant is also calculated perturbatively using the cumulant expansion technique. For a comparison of the two methods, a numerical analysis is carried out.
  • Haruto Muraishi
    1995 Volume 68 Issue 11 Pages 3027-3033
    Published: 1995
    Released: July 10, 2006
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    Amorphous silica was treated with Na2CO3–NaHCO3 and Na2CO3–NaHCO3–NaCl solutions, which are related to the alkaline brine in Lake Magadi in East Africa; its transformation was followed as a function of time under various temperatures (100—160 °C) and pHs (8—12). The reaction occurred in steps. Three kinds of sodium silicates (magadiite, kenyaite, and SiO2-X2) appeared as intermediate phases in solutions with various pH, and finally converted into quartz. The rate of formation of naturally occurring silicates and quartz (chert) was roughly estimated by extrapolating the basis of the data on the temperature dependence of the conversion rate. From those crystallization observations, the preparation conditions for obtaining well-crystallized silicates were determined, and kenyaite was synthesized, which has note yet been obtained as a highly crystallized compound.
  • Kangnian Fan, Wenning Wang, Jingfa Deng
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3035-3040
    Published: 1995
    Released: July 10, 2006
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    Chemisorption properties and vibrational behaviors of molecular oxygen on Ag (110) surface have been studied by the cluster model (CM) and dipped adcluster model (DAM) with an Ag6 cluster. Two stable states, 1A1 [] and 3A2 [001], have been found and assigned to peroxide (O22−) and superoxide (O2) species, respectively. Theoretically predicted adsorption geometries and vibrational frequencies for these states are similar to those measured in the experiments. With the DAM method, the calculated adsorption energies agree well with the experimental value. The O22− species is predicted to be more stable than the O2 species. Cluster size and basis set effects have also been investigated.
  • Yoshiko Kawamura, Jun Yamauchi
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3041-3047
    Published: 1995
    Released: July 10, 2006
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    Diamagnetic bis(1,3,5-triphenylformazanato)nickel(II) was reduced or oxidized by chemical and electrochemical methods. The paramagnetic Ni(I) and Ni(III) complexes thus obtained were studied by means of ESR spectroscopy. Ni(I) complexes formed by alkali metal reductions showed remarkable changes in their g values, depending on the kinds of alkali metal used. The change of g-values, which related to the ionic radii of the alkali metal ions, was well interpreted by the axial coordination effect due to the alkali metal ions. The electrochemical formation of the Ni(I) complex showed a solvent-dependency; the nickel(II) ion was reduced in DMF solution, but not in acetonitrile. The g-components were 2.030 for g// and 2.001 for g. The relation between the two g-components gave a dx2−y2 ground state for the Ni(I) ion in the complex. Their anisotropy was very small. The Ni(II) ion oxidized by both chemical and electrochemical methods showed a dz2 ground state. The three g-components were 2.056, 2.039, and 2.000 in DMF, which are similar to those obtained from the other oxidation methods.
  • Seiichiro Nakabayashi, Masatoshi Yanagida, Kohei Uosaki
    1995 Volume 68 Issue 11 Pages 3049-3053
    Published: 1995
    Released: July 10, 2006
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    The CdS particles are irradiated by the green light from an Ar laser. The irradiation produces the electron-hole pairs and other excited states in the particle. The lifetime of the excited state is ca. 10 μs, which is extremely long compared with the recombination time of the electron and hole pairs. This long-life state forms an optical absorption band in the excitation-modulated transmission spectra. The relationship between the spectral intensity and the strength of the excitation light suggests that this absorption band is caused by the photoionization of the intervalence states and the change in the electrostatic field in the CdS particles.
  • Miyao Inoue, Toshihiro Yamase
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3055-3063
    Published: 1995
    Released: July 10, 2006
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    The acidification of aqueous solutions containing Na2MoO4·2H2O in the presence of a chiral lysine ligand (D- and L-form) gives octamolybdates coordinating two lysine ligands, Na2[Mo8O26(D-lysH2)2]·8H2O (Mo8-D) and Na2[Mo8O26(L-lysH2)2]·8H2O (Mo8-L) (where lysH2 is 2,6-diammoniohexanoato), respectively. These two compounds crystallize with triclinic symmetry in the space group P1, the cell parameters being a = 10.782(2), b = 11.241(5), c = 10.027(2) Å, α = 93.21(2), β = 102.86(2), γ = 112.98(2)°, V = 1077(1) Å3, and Z = 1 for the Mo8-D, and a = 10.783(4), b = 11.246(3), c = 10.019(4) Å, α = 93.21(3), β = 102.75(3), γ = 112.98(2)°, V = 1077(2) Å3, and Z = 1 for Mo8-L. The X-ray crystal structures of these two species have been solved by the MITHRIL direct method and refined to R = 0.0337 and 0.0312 for Mo8-D and -L, respectively. The chiral lysine ligands are coordinated via their carboxylate-oxygen atoms at the vacant sites on the two five-coordinate molybdenum for the centrosymmetric γ-[Mo8O26]4− anion to retain their configuration with a resultant formation of optically-active octamolybdate species.
  • Hideyuki Sawatari, Takeshi Toda, Tomoo Saizuka, Chisen Kimata, Akihide ...
    1995 Volume 68 Issue 11 Pages 3065-3070
    Published: 1995
    Released: July 10, 2006
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    Rare earth elements in coastal seawater were preconcentrated by using chelating resin in a batch method and determined simultaneously by inductively coupled plasma mass spectrometry (ICP-MS). In this procedure, matrix components (Na, K, Mg, and Ca) were eliminated to reduce matrix effects in ICP-MS analysis and rare earth elements were concentrated by a concentration factor of 100. The pH dependence of the recovery, resin amounts, amount of ammonium acetate for washing, and elution of adsorbed metals with nitric acid were examined in details to optimize the experimental conditions in sample pretreatment. All rare earth elements in coastal seawater were determined at the ppt or sub-ppt level successfully by the present analytical method.
  • Junichi Ishikawa, Hidefumi Sakamoto, Tamao Mizuno, Makoto Otomo
    1995 Volume 68 Issue 11 Pages 3071-3076
    Published: 1995
    Released: July 10, 2006
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    Cyclic and acyclic dithiamonoaza, tetrathiamonoaza, and tetrathiadiaza analogs of polyethers bearing a hydrazone moiety on nitrogen atom(s) were synthesized. Their acidity constants in 1,4-dioxane–water solution and stability constants of hydrazones derived from dithiamonoaza and tetrathiamonoaza analogs of polyethers for some heavy metal ions in same acidic media were measured spectrophotometrically. Hydrazones of cyclic and acyclic tetrathiamonoaza series had highly Ag+-selective complexability.
  • Masahiro Mikuriya, Keiichi Nakadera, Takanori Kotera, Tadashi Tokii, W ...
    1995 Volume 68 Issue 11 Pages 3077-3083
    Published: 1995
    Released: July 10, 2006
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    Tetranuclear manganese(III) complexes with 2,6-bis(salicylideneaminomethyl)-4-methylphenol (H3L), [Mn4(L)2(O)2(CH3COO)2]·2CH3CN (1) and [Mn4(L)2(O)2(C6H5COO)2]·2CH3OH (2), have been synthesized and characterized by infrared and electronic spectra, cyclic voltammetry, and temperature dependence of magnetic susceptibilities (4—300 K). The molecular structure of 1 was determined by single-crystal X-ray structure analysis. Complex 1 has a tetranuclear structure, in which two incomplete cubanes are sharing faces by the oxo-bridges. The magnetic susceptibility data show an overall antiferromagnetic interaction.
  • Kazutoshi Endo, Shukuro Igarashi
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3085-3090
    Published: 1995
    Released: July 10, 2006
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    The characteristics of coproporphyrin III (Copro III) as a chelating agent, a chromogenic agent, and a luminescence agent for metal ions were studied. Copro III forms 1 : 1 complexes with Co(II), Cu(II), Mn(II), Ni(II), Pd(II), and Zn(II). Copper, palladium, and zinc complexes exhibit phosphorescence at liquid nitrogen temperature (77 K), and the intensity of the palladium complex (λPdmax = 659 nm) is 10 and 13 times larger than that of the copper and zinc complexes (λCumax = 685 nm, λZnmax = 702 nm), respectively. Based on these facts, a low-temperature phosphorimetric determination of the 10−8 mol dm−3 level of palladium was developed. The detection limit (S/N = 3 using a 150 W xenon arc lamp as a light source) was 8 × 10−9 mol dm−3, and the relative standard deviation was 2.8% for 6 × 10−7 mol dm−3 Pd(II) (7 determinations). Interference from many metal ions was avoided by selective extraction of palladium(II) as an ion-pair of the bromo complex with H2SO4-tetrabutylammonium bromide-methyl isobutyl ketone systems, followed by back extraction with acetate buffer solution (pH 5.0).
  • Yuko Hasegawa, Takeshi Ohyama, Shoichi Katsuta
    1995 Volume 68 Issue 11 Pages 3091-3094
    Published: 1995
    Released: July 10, 2006
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    The extraction behavior of lanthanoids(III) with 1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedione (TTA) and benzoic or phenylacetic acid from 0.1 M sodium perchlorate media into chloroform has been examined at 298 K. The extraction curves are interpreted by the extraction of the adducts of the TTA chelates accompanied with two molecules of the carboxylic acids at maximum as well as the extraction of the TTA chelate. The adduct formation constants decrease generally with the atomic number, but in the middle of the series, they change only slightly, then decrease more rapidly for the heavy elements. Such a trend indicates a change of the coordination number in the middle of the series.
  • Kazuhiko Tsukagoshi, Kai Yu Yu, Mizuo Maeda, Makoto Takagi, Tohru Miya ...
    1995 Volume 68 Issue 11 Pages 3095-3103
    Published: 1995
    Released: July 10, 2006
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    In accordance with the concept of Surface Imprinting, as proposed by the present authors, a Cu(II)-imprinted microsphere was studied in detail in order to obtain information about the origin of the imprinting effect. Unimprinted and Cu(II)-imprinted microspheres were prepared under several pH (4.0, 5.0, 5.6, or 6.0) conditions in second-step polymerization. The obtained microspheres were characterized regarding particle form, size-distribution pattern, average diameter, Cu(II) adsorption behavior, and so on. During preparation at pH 4.0—5.6 in the second-step polymerization, imprinted microspheres adsorbed Cu(II) more effectively than did unimprinted microspheres in this pH range, indicating a clear metal-imprinting effect. On the other hand, the imprinting effect was not observed during preparation at pH 6.0, because of the formation of copper(II) hydroxide precipitates. The maximum imprinting effect was provided by microspheres obtained at pH 5.6. Spectroscopic studies were made on Cu(II)-loaded microspheres. The FT-IR spectra suggested that carboxyl groups on the microsphere surface participated in the Cu(II) binding in their ionized carboxylate forms. An FE-SEM (ångstrom SEM) observation of the microsphere indicated a smooth surface structure at the 10 nm level. The collected data indicate that the origin of the imprinting effect on a Cu(II)-imprinted microsphere is the interaction between Cu(II) and the carboxylate group at the aqueous-organic interface, supporting the concept of Surface Imprinting.
  • Akira Takadate, Toshinobu Masuda, Chiyomi Murata, Toshiharu Tanaka, Sh ...
    1995 Volume 68 Issue 11 Pages 3105-3110
    Published: 1995
    Released: July 10, 2006
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    Three coumarin reagents carrying crown-ether moieties as catalytic sites for the fluorescence derivatization of carboxylic acids were designed and synthesized. The catalytic abilities of these reagents were evaluated based on the stability constants (Ks) for complexation with metal acetates in methanol. The derivatization reactions of carboxylic acids with these reagents proceeded self-catalytically without crown-ether catalysts, and gave the corresponding coumarin esters in good yields. It was found that their reactivities significantly depended upon the metal-binding ability of the reagent molecules from kinetic treatments of the reactions. The derivatized products showed remarkably high fluorescence quantum yields of above 0.8 in methanol. These results suggested that the functionalization of reagents was a quite useful approach for the development of new-type analytical reagents.
  • Ingeborg Csöregh, Olga Gallardo, Edwin Weber, Susan A. Bourne, No ...
    1995 Volume 68 Issue 11 Pages 3111-3120
    Published: 1995
    Released: July 10, 2006
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    9-Phenylfluoren-9-ol (1), 2,7-dibromo-9-phenylfluoren-9-ol (2), and 9-phenylethynylfluoren-9-ol (3) enclathrate different six-membered heterocyclic guests involving piperidine, thioxane, dioxane, and morpholine. X-Ray crystal structure determinations of corresponding inclusion compounds [1·piperidine (1 : 1), 1·thioxane·dioxane (2 : 2 : 1), 2·morpholine (1 : 2), and 3·morpholine (1 : 1)] are reported, showing remarkable variety in the packing relations. Host compound 1 forms H-bonded 1 : 1 host : guest units with both piperidine and thioxane, but in the latter case additional dioxane guests are incorporated in the crystal, thus yielding a ternary complex. Host compound 3 is capable of forming closed loops of hydrogen bonds with full hydrogen bond saturation in its inclusion compound with morpholine, whereas in the related morpholine complex of 2 H-bonded 1 : 2 associates are created without maximal saturation of the hydrogen bonds, and with different binding modes for the two guests of the stoichiometric unit. In the crystals, the various H-bonded host-guest units are linked together by Van der Waals’ forces, occasionally supported by weak electrostatic interactions. The stabilities of the four different inclusion compounds were studied by thermal analysis indicating complex decomposition modes.
  • Nobuhiro Itoh, Haruo Matsuyama, Masato Yoshida, Nobumasa Kamigata, Mas ...
    1995 Volume 68 Issue 11 Pages 3121-3130
    Published: 1995
    Released: July 10, 2006
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    Both enantiomers of (S)- and (R)-4-phenyl-1,5-diazacyclooctan-2-ones (7) were synthesized stereoselectively with good optical purity by the asymmetric conjugate addition of pyrazolidine to optically active vinyl sulfoxides, t-butyl (E)-2-[(R)- and (S)-p-tolylsulfinyl]cinnamates, respectively. Starting from 7, a synthesis of optically active homaline was achieved.
  • Mohsen Abdel-Motaal Gomaa
    1995 Volume 68 Issue 11 Pages 3131-3135
    Published: 1995
    Released: July 10, 2006
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    Benzylideneanilines react with 2,3-dichloro-1,4-naphthoquinone and 2,3-dicyano-1,4-naphthoquinone to give 2-arylamino-3-chloro-1,4-naphthoquinones and 2-arylamino-3-cyano-1,4-naphthoquinones respectively together with the corresponding aldehydes. Similarly benzylideneanilines react with 2-(dicyanomethylene)-1,3-indandione to give 2-arylamino-2-(1,3-dioxo-2-indanylidene)acetonitriles.
  • Yasumasa Sakakibara, Hiroji Enami, Hiroshi Ogawa, Shinpei Fujimoto, Hi ...
    1995 Volume 68 Issue 11 Pages 3137-3143
    Published: 1995
    Released: July 10, 2006
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    The cyanation of β-bromostyrenes catalyzed by Ni(PPh3)n, which was generated in situ from NiBr2(PPh3)2–Zn–PPh3 (Ni : Zn : P = 1: 3 : 2 molar ratio), was at first examined with various MCN (M = K, Na)-dipolar aprotic solvent systems by several procedures. The presence of excess cyanide ion inhibited the reaction. However, when the KCN–DMF system with some intermediate cyanide solubility was used, the nitriles were obtained in high yields and high stereoselectivity at 50 °C by almost all of the procedures attempted. On the contrary, the KCN–HMPA and KCN–MeCN systems with low cyanide solubilities accelerated the coupling of the halides to inhibit the cyanation, and in general the NaCN–DMF and NaCN–HMPA systems with high cyanide solubilities needed to reduce Ni(II) before adding MCN in order to make the catalytic reaction start. Vinyl halides such as 1- and 2-halo (Cl, Br)-1-alkenes, 2-bromo-2-butenes, 3-bromo-3-hexenes, and 1-chlorocyclohexene were also cyanated using suitable procedures and MCN–solvent systems to give the corresponding nitriles in high yields and fair-to-good stereoselectivities. However, with (Z)-2-ethoxy-1-bromoethene the (E)-nitrile, though its selectivity markedly varied with the reaction temperature, was obtained as the main product. The cyanation of ethyl (Z)-β-bromoacrylate and ethyl α-bromoacrylate was unsuccessful due to polymerization.
  • Tadahiro Kato, Akira Hiraide, Miki Suda, Takuro Kanbe, Tetsuo Nozoe
    1995 Volume 68 Issue 11 Pages 3145-3149
    Published: 1995
    Released: July 10, 2006
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    The oligoethylene glycol derivatives having tropolonoid moieties at both terminals were synthesized. The diethylene to pentaethylene glycol derivatives formed Zn complex in an intramolecular fashion, which extracted metal picrates from the aqueous solution. The larger cooperativity was observed in the extractions of alkaline earth metal ions as compared with those of alkaline metal ions.
  • Chung-gi Shin, Yutaka Nakamura, Yasuhiro Yamada, Yasuchika Yonezawa, K ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3151-3160
    Published: 1995
    Released: July 10, 2006
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    The stereoselective synthesis of an amino acid component called Fragment D, N,O-diprotected 2-[(1S,3S)-1-amino-3-carboxy-3-hydroxypropyl]thiazole-4-carboxylic acid of a macrobicyclic peptide antibiotic nosiheptide, was achieved by two routes. The dipeptide, Fragment B-C, 2-[(Z)-1-(N,O-isopropylidene-L-threonylamino)-1-propenyl]thiazole-4-carboxylic acid was also synthesized by the thiazole ring formation from (Z)-2-(N,O-diprotected L-threonylamino)-2-butenethioamide with ethyl bromopyruvate. The coupling of two components by using a condensing agent gave the expected tripeptide 2, which is an important partial skeleton of the nosiheptide.
  • Michio Kondo, Hiroshi Kitajima, Teruo Yasunaga, Hiroaki Kodama, Tommas ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3161-3167
    Published: 1995
    Released: July 10, 2006
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    Based on increased affinity and selectivity of dimeric enkephalin analogs for opioid receptors, divalent interactions have been demonstrated between opioid peptides and receptors. To explore the receptor multivalency suggested by fluorescent microscopic studies, a novel type of tetrameric enkephalin analog was designed and synthesized. The tetrameric enkephalin comprises four [D-Ala2, Leu5]enkephalin molecules coupled with the amino groups of the gem-diamino derivative of cystine, which was derived from cysteinamide by a Hofmann-type rearrangement, causing an amide-to-amine conversion. By the reduction of the gem-cystine disulfide bond in the tetramer, two dimeric analogs with a free or p-methoxybenzyl-protected mercapto group were also prepared. The receptor binding characteristics of these tetramer and dimers for the δ and μ receptors were analyzed in an NG108-15 cell and rat-brain membranes. The affinity of the tetrameric analog for the δ receptors was about equal to that of the dimers, but 2—4-fold lower for the μ receptors. The dimers were 5—8-fold δ-selective, and, thus, the tetramer exhibited a high selectivity for the δ receptors. A divalent interaction mechanism was considered between the tetrameric ligand and the δ opioid receptors.
  • Masahide Yasuda, Tomoko Wakisaka, Ryuji Kojima, Kimiko Tanabe, Kensuke ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3169-3173
    Published: 1995
    Released: July 10, 2006
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    The photoadditions of ammonia and alkylamines (RNH2) to 5-hydroxy- and 5-alkoxy-5H-dibenzo[a,d]cycloheptene derivatives (2) occurred at the C10–C11 double bond upon the irradiation of 2 with RNH2 in the presence of p-dicyanobenzene. The resulting 5-substituted 10-alkylamino-10,11-dihydro-5H-dibenzo[a,d]cycloheptenes were converted to 5-substituted N-alkyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imines by a treatment with AcOH.
  • Takashi Tsuno, Kunio Sugiyama
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3175-3188
    Published: 1995
    Released: July 10, 2006
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    The Photochemistry of 5-[2-(1,2-propadienyl)-substituted alkylidene]-2,2-dimethyl-1,3-dioxane-4,6-diones has been studied. These acylals formed an intramolecular charge-transfer (CT) complex between the 1,2-propadienyl and vinyl moieties in acetonitrile and in hexane, the direct photolyses of which gave (1-alkenylidene)cyclopropanes as the main products, and the intramolecular [2+2] cycloadducts, 3-alkylidene-2′,2′,5,5-tetramethylspiro[bicyclo[2.1.0]pentane-2,5′-[1,3]dioxane]-4′,6′-diones as minor products. The (1-alkenylidene)cyclopropanes were produced from the enol intermediate via a preferred 1,5-hydrogen transfer of a diradical, which was formed via an intramolecular CT excited state. On the other hand, the acetone-sensitized photolyses afforded mainly the intramolecular [2+2] cycloadducts. It is considered that the lowest triplet energies of these acylals in acetonitrile were estimated to lie in the range of 250—290 kJ mol−1, and that these energies were near to the values of the reported triplet energies of α,β-unsaturated esters, because the allene underwent a [2+2] cycloaddition to the triplet vinyl moiety, excited by triplet sensitization.
  • Mitsunobu Nakamura, Koichi Sawasaki, Yoshiki Okamoto, Setsuo Takamuku
    1995 Volume 68 Issue 11 Pages 3189-3197
    Published: 1995
    Released: July 10, 2006
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    Upon UV irradiation in acetonitrile, tri-1-naphthyl phosphate and di-1-naphthyl methylphosphonate underwent intramolecular rearrangement and ipso-coupling to give 1,2′-binaphthalen-1′-ol and 1,1′-binaphthalene, respectively. In the photolyses of tris(4-methoxy-1-naphthyl) phosphate and bis(4-methoxy-1-naphthyl) methylphosphonate in methanol, 4,4′-dimethoxy-1,1′ -binaphthalene, 1′,4,4′-trimethoxy-1,2′-binaphthalene, and 2,4,4′-trimethoxy-1,1′-binaphthalene were generated. Tri-9-anthryl phosphate and di-9-anthryl methylphosphonate underwent intramolecular (4+4) photocycloaddition between two anthryl groups. The fluorescence spectra of the naphthyl derivatives had two emission bands ascribed to an intramolecular excimer and a monomer, but the fluorescence spectra of the anthryl derivatives had only a monomer emission band. These photoluminescence behaviors are closely related to the reactivities of the compounds.
  • Masaaki Mishima, Kiyoshi Arima, Hiroki Inoue, Satoshi Usui, Mizue Fuji ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3199-3208
    Published: 1995
    Released: July 10, 2006
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    Relative chloride ion affinities of 48 carbocations have been measured by the chloride ion transfer equilibrium of benzyl chlorides in the gas phase. The substituent effects on the chloride affinity of benzyl cation have been analyzed in terms of the LArSR Eq., giving a ρ = −14.0 and an r+ = 1.29. The r+ value higher than the corresponding value of unity for the α-cumyl(2-phenyl-2-propyl) cation clearly indicates that the benzyl cation has an enhanced resonance demand in the intrinsic carbocation stability compared with that of the α-cumyl one. Most importantly, the unique r+ value of 1.29 for the gas-phase benzyl cation stability has been found to be identical with the value observed for the kc ionization process of the solvolysis of the activating substituent range of benzyl tosylates. The identity of the r + value, which is consistent with previous observations for the relevant benzylic carbocation systems, suggests that the intramolecular charge-delocalization in the transition state of the kc solvolysis should be quite close to that of the carbocation intermediates. It is concluded that the exalted r+ value observed for the kc solvolysis of benzyl tosylates is not a correlational artifact arising as a result of the non-linearity caused by the kcks mechanistic transition but is due to the enhanced resonance stabilization of the benzyl cation compared with the α-cumyl cation.
  • Hiroshi Uyama, Hideharu Kurioka, Junji Sugihara, Izuru Komatsu, Shiro ...
    1995 Volume 68 Issue 11 Pages 3209-3214
    Published: 1995
    Released: July 10, 2006
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    Enzymatic oxidative polymerization of cresols has been performed by using peroxidase catalyst in two types of polymerization solvent: an aqueous organic solution and a reverse micellar solution, to produce polymeric materials. Peroxidases derived from horseradish and soybean were employed as catalyst. The resulting polymers were partly soluble in DMF and DMSO, but, insoluble in water and other common organic solvents. The molecular weight of the DMF-soluble part was measured by GPC as ca. 5000. The solubility and molecular weight were dependent upon the polymerization condition and monomer structure. From IR and UV analyses, the polymer was found to be composed of a mixture of phenylene and oxyphenylene units. The polymer possessed no clear glass transition or melting points. TG analysis exhibited that the present polymers have relatively high thermal stability. The stability of the polymer from o- and m-cresols was better than that from the p-isomer. The polymer remained in around 40 weight % yield at 1000 °C under nitrogen.
  • Akira Sekiguchi, Masaaki Ichinohe, Tetsuo Nakanishi, Chizuko Kabuto, H ...
    1995 Volume 68 Issue 11 Pages 3215-3220
    Published: 1995
    Released: July 10, 2006
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    Phenyl- and silyl-substituted ethylene dianion dilithiums, [1-phenyl-1,2,2-tris(trimethylsilyl)ethylene]{bis[(dimethoxyethane)lithium(I)]} (2) and [1,1-diphenyl-2,2-bis(trimethylsilyl)ethylene][tris(tetrahydrofuran)dilithium(I)] (4), were prepared and characterized by X-ray crystallography as well as NMR spectra. The crystal structures of 2 and 4 revealed interesting structural features. One of the lithium cations was located near to the two central carbon atoms, ipso and ortho carbons of the phenyl ring, while the other one was found above the benzene ring. The central C–C bond is twisted by ca. 90° for 2 and ca. 70° for 4.
  • Masaru Tada, Ritsuko Nagasaka
    1995 Volume 68 Issue 11 Pages 3221-3225
    Published: 1995
    Released: July 10, 2006
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    Photolysis or thermolysis of (phenylseleno)cobaloxime gives a pair of radicals: phenylseleno radical and cobaloxime radical, which are considered to be equilibrated with the ion pair by a single electron transfer. The radical addition on the acetylenic moiety takes place when the 2-propynyl derivatives have weak leaving groups (OH, OPh, OAc). On the other hand, the ionic substitution with phenylseleno anion takes place on bromides and tosylates.
  • Toshikazu Ibata, Xin-Zhuo Zou, Tetsuo Demura
    1995 Volume 68 Issue 11 Pages 3227-3232
    Published: 1995
    Released: July 10, 2006
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    The reaction of 2,3,5,6-tetrachloronitrobenzene with ethylenediamine under high pressure gave mainly a 1 : 1-product and a bridged 2 : 1-product by the substitution of a nitro group and/or an o-chlorine atom. The ratio of the products varied depending upon the amount of amine used. Other diamines, such as 1,4-butanediamine cis-and trans-1,2-cyclohexanediamines, m-xylylenediamine, and o-phenylenediamine, gave similar results. On the other hand, N,N′-dimethylethylenediamine and N,N′-dimethyl-1,3-propanediamine gave cyclization products through successive substitutions of an ortho-chlorine atom and a nitro group by the two methylamino groups of a molecule of diamine. N-Methylethylenediamine afforded a 1 : 1-product through the substitution of a nitro group by a primary amino group together with a cyclic 1 : 1-product through substitutions of an o-chlorine atom and a nitro group by secondary and primary amino groups, respectively.
  • Masanori Wada, Tetsuya Watanabe, Satoko Natsume, Hisashi Mishima, Kats ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3233-3240
    Published: 1995
    Released: July 10, 2006
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    Triarylmethanols of type (4-YC6H4)Φ2COH {Φ = 2,6-(MeO)2C6H3; Y = MeO, Cl, Me2N} were prepared. The methanol, (4-MeOC6H4)Φ2COH, reacted with acids in a variety of solvents to give the triarylcarbenium salts, [(4-MeOC6H4)Φ2C]X or [(4-HOC6H4)Φ2C]X, or 4-bis(2,6-dimethoxyphenyl)methylene-2,5-cyclohexadienone, O=C6H4=CΦ2, depending on the conditions. These carbenium salts further reacted in alcohols, ROH, to give the triarylmethanes, (4-ROC6H4)Φ2CH (R = Me, Et), where the para-substituent, MeO or HO, was substituted by the solvent, accompanied by a reduction at the central carbon. The methanol, (4-ClC6H4)Φ2COH, also reacted with acid to give the carbenium salt or the triarylmethane, depending on the conditions. While the methanol, (4-Me2NC6H4)Φ2COH, also gave the carbenium salt, [(4-Me2NC6H4)Φ2C]X, it was inert against the formation of the triarylmethane under analogous conditions. It reacted with aqueous sodium hydroxide to give O=C6H4=CΦ2 rather than the original methanol. The para-substituent of [(4-MeOC6H4)Φ2C]X was substituted by di- and monoalkylamines, RR′NH, to give [(4-RR′ NC6H4)Φ2C]X (R,R′ = Me,Me; Et,Et; Me,H; Et,H; Bu,H). While [(4-ClC6H4)Φ2C]X reacted with the dialkylamines to give [(4-RR′NC6H4)Φ2C]X, it reacted with monoalkylamines, RNH2, to give [(4-ClC6H4)Φ2C–NRH2]X. [(4-Me2NC6H4)Φ2C]X was hydrolyzed in the presence of diethylamine to give O=C6H4=CΦ2, but reacted with monoalkylamines to give RN=C6H4=CΦ2.
  • Takushi Nagata, Kiyomi Imagawa, Tohru Yamada, Teruaki Mukaiyama
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3241-3246
    Published: 1995
    Released: July 10, 2006
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    Enantioselective aerobic oxidation of sulfides into optically active sulfoxides was achieved by using pivalaldehyde in the presence of a catalytic amount of optically active β-oxo aldiminatomanganese(III) complexes. An acylperoxomanganese complex, formed from the original manganese complex, molecular oxygen, and pivalaldehyde, was supposed to be a key intermediate in the present oxidation. The crystal structure of chloro-{N,N′-bis[3-oxo-2-(2,4,6-trimethylbenzoyl)butylidene]-(1S,2S)-1,2-diphenylethylenediaminato}manganese(III) was determined by X-ray diffraction methods, which suggested that the bulkiness of the substituents in β-oxo aldimine ligand had played an important role in controlling the approach of sulfides to the manganese complex. Kinetic resolution took place during the subsequent oxidation process of sulfoxide into the corresponding sulfone, and the optical purity of the remaining sulfoxide increased.
  • Yasuhiro Mazaki, Kiyoshi Mutai
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3247-3254
    Published: 1995
    Released: July 10, 2006
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    X-Ray crystallographic analysis of the Acceptor-(CH2)2-Donor type compounds, p-O2NC6H4OCH2CH2OAr (Ar = m- and p-Me2NC6H4, and m-Et2NC6H4) and p-O2NC6H4OCH2CH2N(CH3)C6H4OMe-p, has been carried out. Among these, only m-dimethylamino derivative (1) gives dark red prisms in which a close arrangement of the electron-donor and acceptor groups is observed. With regard to the central C–C bond in ArO–C–C–OAr′ or ArO–C–C–NAr′, three of the above-mentioned four compounds show gauche conformation: 1 is the exception. The preference of the gauche , probably characteristic of O–C–C–O (or –N) group, is suggested to be due to a small energy difference between the trans and gauche forms by using the MM2 and the PM3 approximation. Charge-transfer interaction energy in 1 as an intermolecular force is estimated to be barely large enough to make the trans conformation favorable over the gauche.
  • Atsuhiro Osuka, Satoshi Shinoda, Shinji Marumo, Hiroko Yamada, Tetzuya ...
    1995 Volume 68 Issue 11 Pages 3255-3268
    Published: 1995
    Released: July 10, 2006
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    Fucoxanthin-pyropheophorbide dyads, 3c and 4c, and zeaxanthin-pyropheophorbide dyads, 3d and 4d, were prepared as the first example of natural carotenoid-linked pyropheophorbide. Singlet–singlet energy transfer from carotenoid to pyropheophorbide is more efficient in fucoxanthin-pyropheophorbide dyads than the corresponding zeaxanthin-pyropheophorbide dyads, while the singlet excited state of the pyropheophorbide is quenched more strongly in the zeaxanthin-linked molecules. Marked differences in carotenoid-pyropheophorbide singlet excited-state interactions between fucoxanthin and zeaxanthin strongly suggest their different roles in vivo; antenna function for fucoxanthin and energy-dissipation for zeaxanthin. Both carotenoids similarly quench the triplet excited state of the pyropheophorbide through triplet–triplet energy transfer with rates which depend on temperature and the linkage.
  • Tomoshige Kobayashi, Hirokazu Suda, Hiroki Takase, Ryozo Iriye, Hirosh ...
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3269-3275
    Published: 1995
    Released: July 10, 2006
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    2-Phenyl- and 2-(p-tolyl)-4,7-dihydro-4,7-methano-2H-isoindole were synthesized by treatment of 3-(diethoxymethyl)bicyclo[2.2.1]hepta-2,5-diene-2-carbaldehyde with aniline or p-toluidine, followed by reduction with sodium borohydride and acid-catalyzed cyclization. It was concluded that the previous claim of the synthesis of methanoisoindole derivatives was incorrect. 4,7-Dihydro-4,7-methanoisobenzofuran was prepared by the reduction of the norbornadiene-monocarbaldehyde with sodium borohydride and subsequent treatment with Amberlyst-15. The p-tolylmethanoisoindole reacted with dimethyl acetylenedicarboxylate to give a novel 1 : 3 adduct. On the other hand, in the reaction of the methanoisobenzofuran with N-phenylmaleimide, spontaneous oxidation of the Diels–Alder cycloadduct took place to give exclusively its epoxide.
  • Yoshirou Tokimitsu, Norio Ise, Naoki Tanaka, Shigeru Kunugi
    1995 Volume 68 Issue 11 Pages 3277-3282
    Published: 1995
    Released: July 10, 2006
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    Oxidation of uric acid was catalyzed by Cu(II) complexes of polylysines. The presence of the polylysine as the second ligand (in addition to the first ligand; the substrate) showed an enhancement of the intrinsic catalytic activity of Cu(II) ions. Accounting for the apparent substrate inhibition phenomenon, due to the absorbance interference by the intermediate, approximate Km value for the model systems were determined to be around 30—40 μM, which are better than that of the free Cu(II) system, 60—80 μM, and comparable or even better than the Km values for some enzymatic reactions. From the CD spectrum the conformation of the polymer ligands is known to influence the catalytic activity. A preference of partly ordered structure is implied.
  • Atsushi Adachi, Akihiko Kudo, Tadayoshi Sakata
    Type: Accounts
    Subject area: AI
    1995 Volume 68 Issue 11 Pages 3283-3288
    Published: 1995
    Released: July 10, 2006
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    An electrodeposition technique was employed to synthesize CdS and SnS thin films. The optical and photoelectrochemical properties of these films were studied. Red emission peaks of as-deposited CdS thin films were observed around 650—700 nm at 77 K. Anodic photocurrents were observed for the CdS thin films used as semiconductor electrodes. Lowering current densities for the deposition increased both the photoluminescence intensity and the photocurrents. SnS thin films were prepared by a pulsed electrodeposition technique. The films had a large absorption coefficient of 105 cm−1 order. Stirring the electrolyte solution had a drastic effect on the film growth. This suggests that the diffusion of elemental sulfur which reacts with electrochemically formed Sn is the rate determining step of the SnS formation.
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