Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 70 , Issue 12
Showing 1-38 articles out of 38 articles from the selected issue
  • Masatoshi Osawa
    1997 Volume 70 Issue 12 Pages 2861-2880
    Published: 1997
    Released: June 20, 2006
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    Molecules adsorbed on evaporated thin metal films exhibit enormously strong infrared absorption. The thin metal films that exhibit the surface-enhanced infrared absorption (SEIRA) consist of metal particles much smaller than the wavelength of light. Electric field associated with the incident infrared radiation is enhanced via the excitation of localized plasmon of the particles, yielding the absorption enhancement. Preferential orientation and the change in absorption coefficient of molecules caused by chemisorption onto the metal surface provide additional enhancement. Most characteristic observations in SEIRA experiments are well explained by a simple electromagnetic theory. The infrared spectroscopy utilizing the SEIRA effect is promising as a new surface analytical tool. In particular, it is very useful for in situ studies of electrode/electrolyte interfaces. By the combined use of the attenuated-total-reflection technique, reactions and adsorption/desorption of molecules at the interfaces can be investigated at a high sensitivity without the interference from the bulk solution. The high sensitivity of this technique enables dynamic (or time-resolved) infrared monitoring of reactions and other time-dependent phenomena at the electrochemical interface at time-resolutions ranging from microseconds to milliseconds. Two-dimensional correlation analysis of time-resolved spectra highlights certain useful information that is not clearly seen in the usual one-dimensional spectra.
  • Masaaki Yoshifuji
    1997 Volume 70 Issue 12 Pages 2881-2893
    Published: 1997
    Released: June 20, 2006
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    The structures of transition metal complexes with low coordinate organophosphorus compounds are described; these compounds involve diphosphenes, phosphaethenes, phosphaallenes, phosphabutatrienes, and so on of coordination number 2. They are discussed in terms of X-ray crystallographic analysis and 31P NMR analysis.
  • Hiromichi Ohta
    1997 Volume 70 Issue 12 Pages 2895-2911
    Published: 1997
    Released: June 20, 2006
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    An enzyme sometimes provides a entirely hydrophobic chiral reaction field to a synthetic substrate. This is one of the most characteristic features of an enzyme compared to ordinary chemical catalyst. Taking advantage of being able to carry out a reaction of a prochiral compound in this special pocket, it is possible to prepare an optically active product via asymmetric protonation in an aqueous medium. Two such examples are demonstrated in this article, i.e., asymmetric hydrolysis of enol esters, and asymmetric decarboxylation of α-aryl-α-methylmalonic acid to give optically active ketones and α-arylpropionic acids, respectively. Some related reactions are described as well.
  • Amaresh Mishra, Sanjukta Patel, Rajani K. Behera, Bijaya K. Mishra, Go ...
    1997 Volume 70 Issue 12 Pages 2913-2918
    Published: 1997
    Released: June 20, 2006
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    The interaction of a number of cationic dyes (I) with a varying number of methylene groups (Cn) in the alkyl chain attached to pyridyl nitrogen with a cationic surfactant (CTAB) assembly is reported. The binding constant of the dyes (C5 to C18) with the micelle have been calculated, and are found to increase with increasing carbon chain. A plot of the binding constant vs. the chain length shows a curve with a maximum for C16, which is attributed to a compatibility factor. From studies of the electronic and emission spectra it is proposed that a micelle has a hydrophobic force field and that the dyes are localized in various pockets of the field.
  • Wataru Ishida, Yasuyuki Takenaka, Yoko Miyatake, Hirotomo Hase, Masaak ...
    1997 Volume 70 Issue 12 Pages 2919-2923
    Published: 1997
    Released: June 20, 2006
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    Fluorescence emission and cycloaddition reaction induced in 2,5-distyrylpyrazine crystal by ionizing radiation were studied by means of pulse radiolysis and 60Co γ-ray radiolysis. Lifetimes of the fluorescence in the photo-illuminated crystal were also studied for comparison by using pico-second laser photolysis techniques. The fluorescence spectrum obtained by pulse radiolysis was similar to that obtained by laser-photolysis, which led us to conclude that excimers were formed by electron beam-irradiation as well. The occurrence of [2+2] cycloaddition reaction of DSP by γ-irradiation was monitored by observing the concentration change of the olefinic double bond. The high G-value, 4—5, for the decrease of the olefinic double bond suggested efficient activation of DSP in the irradiated crystal.
  • Kazuya Ogawa, Kou Nakata, Kazuhiko Ichikawa
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 2925-2933
    Published: 1997
    Released: June 20, 2006
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    Zinc complexes with bisbenzimidazole, [ZnL(PhCOO)2] 1, [ZnLCl2] 2, and [ZnL2]2+ 3, have been synthesized, where L = 2,2′-thiodimethylenebis(benzimidazole). Their molecular structures were determined based on X-ray crystal structure and extended X-ray absorption fine structure (EXAFS) analyses. The molecular structure of 1·1.5DMF shows a distorted tetrahedral geometry around Zn(II) coordinated by each nitrogen atom of two benzimidazolyl groups and each oxygen atom of two benzoate ions. In solutions of 2 or 3·(ClO4)2 the same chemical species, [ZnLCl2] or [ZnL2]2+, exist as in the coordination structure around zinc in each crystal. The combination of 13C NMR data with the most probable molecular structures of zinc complexes in 1, 2, and 3, determined by X-ray crystal structure and EXAFS analyses, allowed us to assign the two different chemical species, [ZnL(PhCOO)2] and [ZnL2]2+, as the major and minor components, respectively, in a solution of 1. A kinetic study of the ligand-exchange reaction between PhCOO and L was provided us with the lifetimes of the chemical species of [ZnL(PhCOO)2] and [ZnL2]2+: 66 ms and 10 ms at −10 °C, respectively. The major species produced by a zinc-assisted supramolecular process in solution is the same type of chemical species [ZnL(PhCOO)2] as in the coordination structure around zinc in the crystal of 1·1.5DMF. The ESI mass spectra of a solution of 1, 2, and 3·(ClO4)2 supported the chemical species of [ZnL(PhCOO)2], [ZnL2]2+, and [ZnLCl2] in solution.
  • Kazunari Tanzawa, Noboru Hirota, Masahide Terazima
    1997 Volume 70 Issue 12 Pages 2935-2942
    Published: 1997
    Released: June 20, 2006
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    A nonlinear optical effect due to the thermal energy after the photoexcitation of a light-absorbing chromophore or a metal ion contained in micro droplets (oil in water (O/W) and water in oil (W/O)) was investigated by the time-resolved transient grating method. The temporal profiles of the diffusive components of the thermal grating signals are very different from that observed in a homogeneous solution, and also depend on the emulsion systems. The profiles were consistently analyzed in terms of the droplet heating, thermal expansion, and subsequent cooling process. The size of the droplets determined from this analysis agrees with that from the dynamic light scattering method.
  • Akihiro Nakano, Koichi Tateishi
    1997 Volume 70 Issue 12 Pages 2943-2949
    Published: 1997
    Released: June 20, 2006
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    The phase behavior was investigated in water/phytoglycogen/water-soluble nonionic surfactant (poly(oxyethylene) type surfactant, CmEOn) systems, showing that phytoglycogen is precipitated by the addition of those surfactants. Therefore, the effect of the hydrophile–lipophile balance (HLB) on the dispersion stability of phytoglycogen (DSP) was assessed.
    At constant-temperature, phytoglycogen in a lower HLB surfactant system dispersed more stably than that in a higher HLB surfactant system. With raising the temperature, the DSP in the higher HLB surfactant system was improved, whereas phytoglycogen became to disperse unstably in a low-HLB surfactant (C12EO7) system. In the C12EO9 and C12EO10 systems, the DSP was improved over a range of lower temperatures, whereas phytoglycogen became to disperse unstably over a range of higher temperatures. We proposed a schematic representation on the phase behavior in water/phytoglycogen/nonionic surfactant systems. It was clarified that DSP in phytoglycogen and surfactant-coexisting systems depends on the HLB and the aggregation number of each surfactant. Furthermore, the characteristics of surfactant micelles in water were evaluated macroscopically from the investigation.
  • Hironobu Umemoto, Yuki Kimura, Takashi Asai
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 2951-2956
    Published: 1997
    Released: June 20, 2006
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    Ground state NH radicals could be detected as products of the reactions of N(22D) with simple alkane hydrocarbons. N(2D) was produced by two-photon dissociation of NO, while NH (X 3Σ) was detected by laser-induced fluorescence. The nascent vibrational population ratio, NH(v″ = 1)/NH(v″ = 0), was determined to be 0.6, 0.5, 0.5, and 0.5 for CH4, C2H6, C3H8, and C(CH3)4, respectively. These ratios are smaller than that for H2, 0.8, but much larger than the prior ones. The nascent rotational state distributions of NH(X 3Σ, v″ = 0) were determined for CH4, C2H6, and C3H8. The distributions were much hotter than the prior ones and showed little dependence on the complexity of the hydrocarbons. This suggests that the intermediate complexes which lead to the production of NH are short-lived and decompose before intramolecular vibrational redistribution (ivr). The yields for the production of NH(v″ = 0) for heavy alkanes were smaller than that for CH4. There must be exit channels other than NH production, such as C–C bond cleavage processes.
  • Kazuhiro Tanaka, Toshinao Kawai, Hidetoshi Kita, Kenichi Okamoto, Yasu ...
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 2957-2962
    Published: 1997
    Released: June 20, 2006
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    Positron-annihilation measurements were performed for polymer films containing quenchers of ortho-positronium (o-Ps) in order to obtain information about the migration of o-Ps. The diffusion coefficients of o-Ps, estimated from the quenching-rate constants, were (1—2) × 10−6 cm2 s−1 at 298 K, which lead to root-mean-square distances of 1.5—2.4 nm during its lifetime. o-Ps is considered to migrate through more than several free-space holes until pick-off annihilation, suggesting that the size estimated from the lifetime of o-Ps corresponds to an average size weighted to the larger size because o-Ps is more stable in larger holes. The diffusion coefficients of o-Ps were compared with those of gas molecules, leading us to conclude that the migration of o-Ps follows a different mechanism from that of the diffusion of gas molecules. The quenchers also had the effect of inhibiting o-Ps formation in the polymers, and the inhibition coefficients were determined to be 6—17 M−1, which are as high as the corresponding values in benzene solutions.
  • Hiroshi Ono, Shin’ichi Ishimaru, Ryuichi Ikeda, Hiroyuki Ishida
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 2963-2972
    Published: 1997
    Released: June 20, 2006
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    1H, 19F, and 14N NMR, powder X-ray diffraction, and differential scanning calorimetry (DSC) were measured in trimethylethylammonium perchlorate, hexafluorophosphate and nitrate, [(CH3)3NCH2CH3]X (X = ClO4, PF6, NO3). Three, four and four solid phases were obtained for perchlorate, hexafluorophosphate, and nitrate, respectively, in the temperature ranges from 77 K to their decomposition temperatures. X-Ray powder patterns showed that the highest-temperature solid phases of perchlorate and hexafluorophosphate are CsCl-type cubic, while that of nitrate is NaCl-type cubic. The second highest-temperature phases of perchlorate and hexafluorophosphate form tetragonal lattices. The NMR study revealed that the cations perform isotropic rotation as well as self-diffusion in the CsCl-type cubic and tetragonal phases of perchlorate. In the cubic phase of hexafluorophosphate, isotropic rotation and self-diffusion of both anion and cation were observed. In the NaCl-type cubic phase of nitrate, isotropic rotation of both ions was detected. The structures in the highest- and second highest-temperature phases of the three salts were found to be dynamically disordered. Especially, the highest-temperature phases of perchlorate and hexafluorophosphate can be classified into the ionic plastic phase of the CsCl-type structure. Activation energies of the ionic motions in these phases were evaluated. Motional modes of the ions in the lower temperature phases were also deduced.
  • Takayuki Ohmae, Shigeyuki Aono
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 2973-2979
    Published: 1997
    Released: June 20, 2006
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    The electronic structures of the Hückel- and Möbius type species are investigated in the Hückel approximation. The Green’s function approach is employed to evaluate the total energy, the charge density and the bond order of various series. The results are successfully expressed in analytical forms, which displays the Hückel 4m + 2 and the Möbius 4m rules very clearly.
  • Susumu Tanaka, Noriko Onoda-Yamamuro, Shin’ichi Ishimaru, Ryuich ...
    1997 Volume 70 Issue 12 Pages 2981-2986
    Published: 1997
    Released: June 20, 2006
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    1H NMR spin-lattice relaxation times, T1 and T1ρ, the second moment M2 of 1H NMR linewidth, 2H NMR spectra, powder X-ray diffraction, electrical conductivity, and thermal measurements have been performed on C12H25NH3Cl and C12H25ND3Cl in the range between room temperature and the melting point. From these measurements, the presence of the rotator phase was revealed above ca. 345 K, where a highly disordered structure characterized by the rapid 2-D self-diffusion as well as the axial rotation of the cations taking place in the lamellar-type double layer structure is formed. These molecular motions, the crystal structure and the thermal nature found in this phase indicate that the rotator phase is close to the plastic crystal and can be described as “a low-dimensional plastic phase”. The determined dynamic parameters of molecular motions in this phase were compared with those in the values reported in the rotator phases of short alkyl chain analogues.
  • Do Won Jin, Tomoshige Nitta, Dong-Won Park
    1997 Volume 70 Issue 12 Pages 2987-2993
    Published: 1997
    Released: June 20, 2006
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    Chromatographic and FTIR techniques were applied to a study of the absorption characteristics of acetone and benzene on a silica gel (SG800) in supercritical CO2 at 313.2 and 333.2 K. The chromatographic isotherms for acetone and benzene have a maximum at a pressure lower than the critical pressure of CO2, and then decrease with increasing pressure. When the temperature increases, the adsorption isotherms decrease in the low-pressure region, and increase in the high-pressure region, providing a crossover at a relatively high pressure. The elution curves of acetone showed tailing, even at high pressures, while those of benzene showed quasi-Gaussian curves at high pressures. The tailing curves for acetone indicate the existence of heterogeneous sites; evidence of hydrogen-bonding formation with surface silanol groups has been provided by IR spectroscopy.
  • Ashok Kumar Singh, Gurudas Bhattacharjee, Manendra Singh, Sudeshna Cha ...
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 2995-2999
    Published: 1997
    Released: June 20, 2006
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    A new 14-membered macrocyclic ligand containing nitrogen donor atoms was prepared and characterized. The macrocycle behaves as a selective chelating ion exchanger for some metal ions. The PVC-based membrane electrode of the macrocycle shows a Nernstian response for nickel(II) ions over a wide concentration range (0.294 to 58.69 × 102 mg dm−3) between pH 3.0 to 7.0. The electrode is found to possess adequate stability and specific selectivity with a response time of 10 s. The sensor can also be used in a partially nonaqueous medium having a 35% (v/v) nonaqueous content. The membrane exhibits excellent selectivity for nickel(II) ions, and no disturbance is observed by normal interferents like Cu2+, Cd2+, Co2+, Pb2+, Zn2+, Mg2+, and Hg2+ ions. The electrode has been successfully used for estimating Ni2+ ions in milk powders, chocolates, and hydrogenated vegetable oils. Small amounts (≤5.0 × 10−5 mol dm−3) of hexadecyltrimethylammonium bromide do not disturb the functioning of the membrane sensor.
  • Shinya Hayami, Takashi Matoba, Shuichi Nomiyama, Takahiko Kojima, Susu ...
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3001-3009
    Published: 1997
    Released: June 20, 2006
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    Several iron(III) complexes with the different hexadentate Schiff-base ligands of N4O2 donor sets were synthesized; these are 1 : 2 condensation products of linear tetramines (3,3,3-, 3,2,3-, 2,3,2- or 2,2,2-tetramine) and salicylaldehyde, acetophenone or benzophenone derivatives. Their crystal structures, Mössbauer spectra, magnetic susceptibilities, electronic spectra and cyclic voltammetry of the complexes were examined. The X-ray structures of the single crystals of [Fe(3,2,3-sal2tet)]NO3 (1), [Fe(3,2,3-sal2tet)]BPh4 (2), [Fe(3,2,3-mpk2tet)]PF6 (3), [Fe(2,3,2-sal2tet)]ClO4 (4), [Fe(2,3,2-3MeO-sal2tet)]ClO4 (5), [Fe(2,3,2-mpk2tet)]ClO4 (6), [Fe(2,3,2-bpk2tet)]ClO4 (7), and [Fe(2,2,2-bpk2tet)]ClO4·EtOH (8) were determined.

    The moieties of the iron atoms of (1), (2), and (3) with 3,2,3-tetramine, and (7) with 2,3,2-tetramine were pseudo octahedral with trans-FeN4O2 geometry. Those of (4), (5), and (6) with 2,3,2-tetramine, and (8) with 2,2,2-tetramine were cis-FeN4O2 geometry. The iron(III) complexes (1), (2), (3), and (7) were in the low-spin state, and the iron(III) complexes (4), (5), (6), and (8) were in the high-spin state.
    In the electronic spectra, the wave lengths of the LMCT bands for the low-spin complexes were longer than those for the high-spin complexes. The values of redox potentials for the low-spin states were suggested to be 0.12 V more negative than those for the high-spin states.

    (Remark: This summary is partially truncated in the html because it exceeds the limit of the system (4000 characters per note). The complete text is given in the pdf.)
  • Mayumi Danjo, Yukari Mizuguchi, Yukari Yagita, Kazuyo Kakiguchi, Tomom ...
    1997 Volume 70 Issue 12 Pages 3011-3015
    Published: 1997
    Released: June 20, 2006
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    The intercalation of nucleic acid-related compounds which have the pyrimidine structure into the layered titanium phosphate, Ti(H2PO4)(PO4)·2H2O (γ-TiP), was examined. The intercalation of cytosine derivatives such as anticancer agent cytarabine was successful. In addition, cytarabine release tests from the obtained cytarabine intercalation compound of γ-TiP were performed in various kinds of solutions containing sodium ions. The release of cytarabine became slower by intercalation into the layered phosphate. Cytarabine release was strongly influenced by the pH value and the concentration of sodium ions in the test solution. In the reaction in aqueous solutions with higher concentrations of sodium ion and/or higher pH values, the ion-exchange of Na+ and protonated cytarabine in the intercalation compound and the disintegration of the layered structure of γ-TiP occurred. On the other hand, in the solutions with the lower sodium ion concentration and the lower pH value, the layered structure of γ-TiP was disintegrated and cytarabine in the interlayer region rearranged.
  • Takayuki Kohiruimaki, Keizo Matsuda
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3017-3023
    Published: 1997
    Released: June 20, 2006
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    The purpose of this study is to synthesize strontium sulfite crystals with characteristic forms by a metasilicate gel-growth method and to determine the optimum conditions for synthesis of the crystals. Strontium ions were diffused into metasilicate gel including sulfite ions in order to synthesize strontium sulfite crystals. The crystals were synthesized in the pH range of 4.0 to 11.0, at a diffusion temperature between 5 and 40 °C, in the following concentration ranges: sodium sulfite, 0.2 to 1.5 mol dm−3, and strontium chloride, 0.2 to 3.0 mol dm−3. As a result, strontium sulfite crystals were obtained in the following four forms: spherical, poly-spherical, ellipsoidal, and spindle. The cause of the crystal form change was found to be a difference in the growth side by comparison of X-ray diffraction patterns. In addition, the optimum conditions which controlled the crystal form were influenced by the pH value in the gel and the temperature.
  • Yoshinori Ihara, Tomomi Sakino, Mieko Ishikawa, Takanori Koyata
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3025-3029
    Published: 1997
    Released: June 20, 2006
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    The solid-phase thermal reactions of trans-diaquabis(diamine)nickel(II) complexes (trans-[Ni(diamine)2(H2O)2]X2) were investigated by means of TG/DTA and DSC, and high-temperature electronic spectrometry, where the diamine is an optically active diamine such as (1S,2S)-1,2-diphenyl-1,2-ethanediamine or (S)-4-methyl-1,2-pentanediamine, and X is Cl, Br, or NO3. Several complexes were peculiarly transformed into cis-[NiX2(diamine)2] upon thermal deaquation-anation, and then isomerized to trans-[NiX2(diamine)2] upon further heating. The results were in contrast to the reactions of the complexes with the corresponding racemic diamines which underwent a simple deaquation-anation, retaining an original trans configuration. The differences must come from a slight difference in the conformation of diamine ligands between trans-[Ni(R-diamine)(S-diamine)(H2O)2]X2 which is obtained for the rac-diamines and trans-[Ni(R- or S-diamine)2(H2O)2]X2 which is obtained for the optically active diamines.
  • Kan Kanamori, Kaori Yamamoto, Takako Okayasu, Naoto Matsui, Ken-ichi O ...
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3031-3040
    Published: 1997
    Released: June 20, 2006
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    Several dinuclear vanadium(III) complexes were prepared using a heptadentate dinucleating ligand containing a bridging alkoxo group. The structures of [V2(dpot)(m-hbza)(H2O)2]·H2O (1b), [V2(bza)(OH)(tphpn)(H2O)2]Cl3·8H2O (2), and [V2(hpnbpda)2]·12H2O (3a) were determined by X-ray crystallography (dpot: 2-oxo-1,3-diaminopropane-N,N,N′,N′-tetraacetate, m-hbza: m-hydroxybenzoate, bza: benzoate, tphpn: N,N,N′,N′-tetrakis(2-pyridylmethyl)-2-oxo-1,3-propanediamine, hpnbpda: N,N′-bis(2-pyridylmethyl)-2-oxo-1,3-propanediamine-N,N′-diacetate). Each vanadium(III) center of 1b adopts a distorted octahedral structure, and the two vanadium centers are bridged by an alkoxo group of dpot and a carboxylato group of m-hbza bridge. Each vanadium center of 2 and 3a, however, takes a heptacoordinate structure. The coordination polyhedron of 2 can be regarded as a capped octahedron, while that of 3a as a pentagonal bipyramid. The two vanadium(III) centers are ferromagnetically coupled in 1b (J = 23.7 cm−1) and 2 (J = 14.6 cm−1), whereas in 3a they are antiferromagnetically coupled (J = −35.2 cm−1). The electrochemistry of the dpot and hpnbpda complexes has also been investigated.
  • Kanji Kubo, Nobuo Kato, Tadamitsu Sakurai
    1997 Volume 70 Issue 12 Pages 3041-3046
    Published: 1997
    Released: June 20, 2006
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    N,N′-Bis(1-pyrenylmethyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (1) and N-(1-pyrenylmethyl)-1,4,7,10,13-pentaoxa-16-azacyclooctadecane (2) were synthesized and found to display unique photophysical properties in the presence of the guest-metal salts. The binding of metal ions to the diazacrown ether 1 cavity inhibited the exciplex formation and changed the distance between two pyrenyl groups. This caused not only an emission-intensity enhancement, but also a large change in the monomer/excimer fluorescence-intensity ratio. The change resulted from the coordinated structure and exchange process between the free host 1 and its metal salt complex in the ground state.
  • Tadashi Endo, Yoshihiro Aono, Takashi Yazawa, Munetoshi Hayashi, Yuuic ...
    1997 Volume 70 Issue 12 Pages 3047-3053
    Published: 1997
    Released: June 20, 2006
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    Oxidation of a pair of associating thiols (1 and 2), each having the binding site [–C(=O)NHC(=O)NH–] and the recognition site (R1 or R2), is examined at several temperatures in alcohols (MeOH, EtOH, n-PrOH, and i-PrOH) and water. The selectivity (r), a measure of molecular recognition of 1 by 2 (or of 2 by 1), in the oxidation is defined as the logarithmic ratio of the yield of an unsymmetrical disulfide (4) to twice that of a symmetrical one (3). It is found that the selectivity in the alcohols each decreases markedly with increasing temperature except for one case, whereas that in water increases with increasing temperature. Correlation of the observed selectivity with factors affecting the selectivity (e.g., intermolecular association, physicochemical properties of solvents, and hydrophobic interaction) is discussed.
  • Michiharu Mitani, Shigenori Hujita
    1997 Volume 70 Issue 12 Pages 3055-3060
    Published: 1997
    Released: June 20, 2006
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    Allyltrimethylsilane reacted with polyhalogen compounds in the presence of copper species, such as copper(I) chloride, copper(II) chloride or metallic copper, to form polyhalo compounds containing an allyl group. Other allylsilane derivatives than allyltrimethylsilane were also subjected to a reaction with carbon tetrachloride. 3-Chloro- or 3-bromo-3-trimethylsilyl-1-propene gave 4,4,4-trichloro-1-trimethylsilyl-1-butene. Ethyl 1-trimethylsilylallyl carbonate afforded ethyl 4,4,4-trichloro-1-butenyl carbonate along with a hydrotrichloromethylation product. 2-Methyl-3-trimethylsilyl-1-propene yielded a product based on the addition of a trichloromethyl group followed by hydrogen-elimination from a 2-methyl group.
  • Akihiro Yamada, Hitomi Kitamura, Kaori Yamaguchi, Seketsu Fukuzawa, Ch ...
    1997 Volume 70 Issue 12 Pages 3061-3069
    Published: 1997
    Released: June 20, 2006
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    The chemical substances which regulate biofilm formation were examined, and a bioassay system which uses marine bacteria with adhering properties was developed. This bioassay system is suitable for screening crude extracts from marine organisms. Using this system, those substances which regulate biofilm formation were isolated from marine organisms. For example, bis(deacetyl)solenolide D was obtained from the marine sponge Psammaplysilla purpurea. Novel nitroalkanes were also isolated from the Okinawan sponge Callyspongia sp. Ethyl N-(2-phenylethyl)carbamate isolated from the marine bacteria SCRC3P79 (Cytophaga sp.) inhibited biofilm formation. Furthermore, the N,N-dichloro, isocyanide, isothiocyanate, and dithiocarbamate derivatives of 2-(4-nitrophenyl)ethylamine, significantly inhibited the growth of marine attaching bacteria. Interestingly, most of the marine sponges examined contained anti-biofilm compounds, such as benzoic acid, aeroplysinin-I, and bromoageliferin.
  • Shih-Jue Lin, Shuan-Ya Jiang, Tian-Chyuan Huang, Cheng-Shyan Dai, Pai- ...
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3071-3074
    Published: 1997
    Released: June 20, 2006
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    A photolysis of 2-diazo-1,3-dicyanoazulen-6(2H)-one in the presence of azulene derivatives in anhydrous ethyl acetate solution afforded 1,2′-biazulene derivatives, which are otherwise difficult to obtain, in good yields, nearly 90% or more. Accompanying by-products, 1,3-dicyanoazulen-6-ol and 2,5′-biazulene derivatives, were also characterized.
  • Tomoya Sawaki, Ken Endo, Kenji Kobayashi, Osamu Hayashida, Yasuhiro Ao ...
    1997 Volume 70 Issue 12 Pages 3075-3079
    Published: 1997
    Released: June 20, 2006
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    5,5′-(9,10-Anthracenediyl)diresorcinol (1) (host) and a terpenoid aldehyde citronellal (2, guest) form a 1 : 2 adduct 1·2(2), in which the guest molecules hydrogen-bonded to the host are closely packed in an extended conformation in the microporous crystal structure of the host. When heated in vacuo, the 1 : 2 adduct loses ca. 1 molecule of the guest to give a 1 : 1 adduct 1·2. The guest 2 included in both adducts undergoes a facilitated intra-adduct ene reaction to afford isopulegol as the main product. Such a reaction in the 1 : 1 adduct occurs smoothly and in a highly stereoselective (ca. 98%) manner. The reaction in the 1 : 2 adduct is less stereoselective and exhibits a sigmoidal progression curve having a significant “induction period”. The present ene reaction of citronellal (2) as either a neat liquid or in a cyclohexane solution is catalyzed by host 1 in the solid state. The allosteric cooperativity observed is discussed in view of a big conformational change associated with the present cyclization reaction.
  • Mizue Fujio, Hiroshi Morimoto, Hyun-Joong Kim, Yuho Tsuno
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3081-3090
    Published: 1997
    Released: June 20, 2006
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    The solvolysis rates of 2,2,2-trifluoro-1-(3-chlorophenyl)-1-(substituted phenyl)ethyl and 2,2,2-trifluoro-1-(3,5-dichlorophenyl)-1-(substituted phenyl)ethyl tosylates or bromides were conductimetrically measured at 25.0 °C in 80% aqueous ethanol. The 3-chlorophenyl-fixed series showed a bilinear Yukawa–Tsuno correlation with ρ = −4.81 and r = 1.41 for substituents more deactivating than 3,5-dimethyl, and with ρ = −6.19 and r = 1.57 for the substituent range more activating than 4-methyl. The bilinear correlation was interpreted in terms of the changing coplanarity of the two aryl rings. The 3,5-dichlorophenyl-fixed substrates gave an excellent linear Yukawa–Tsuno correlation for the substituents ranging from 4-MeO to 4-Cl with ρ = −5.95 and r = 1.69. The variable aryl rings in this series show the largest extent of resonance interaction with the extraordinary deactivated carbenium ion center by α-CF3 and α-(3,5-dichlorophenyl) groups in the transition state. The optimization of the geometries of 2,2,2-trifluoro-1,1-diphenylethyl cation and some ring-substituted derivatives was performed at the RHF/6-31G* level. The symmetric diaryl cations have equivalently twisted conformations, while in unsymmetric ones the more stabilizing aryl group is less twisted from the plane of the positive sp2 carbon. The observed variation of r and ρ parameters is accommodated by geometrical changes of the incipient cation.
  • Katsuyuki Ogura, Akio Kayano, Motohiro Akazome
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3091-3101
    Published: 1997
    Released: June 20, 2006
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    High 1,2-asymmetric induction was realized by the addition of a 1-hydroxy-1-methylethyl radical to conformationally flexible (E)-γ-hydroxy α,β-unsaturated carboxylic esters and sulfones (1 and 2, respectively). Upon the irradiation (> 290 nm) of (E)-1 and benzophenone in 2-propanol, the 1-hydroxy-1-methylethyl radical was generated in situ and added to (E)-1 with high anti-stereoselectivity. The bulkier is the γ-alkyl group of (E)-1, the higher does the selectivity become. Similarly, a radical addition to the acetates of (E)-1 and (E)-2 proceeded stereoselectively in an anti fashion, whereas (Z)-2 exhibited syn-stereoselectivity. The mechanism for these stereoselective radical additions is discussed.
  • Ken-ichiro Imamura, Yoshinori Yamamoto
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3103-3110
    Published: 1997
    Released: June 20, 2006
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    Sugar-part modified closo-carboranyluridines, 5-(o-carboran-1-yl)-2′,3′-dideoxy-3′-thiauridine 5 and 5-(o-carboran-1-yl)-2′,3′-dideoxy-2′α-phenylthiouridine 6, were synthesized. These newly synthesized closo-carboranyluridines, 5 and 6, and previously synthesized 5-(o-carboran-1-yl)uridine 1 were converted to the corresponding nido-carboranyluridines 18, 19, and 17, respectively. Water-solubility of nido-type 17 was about 100 times higher than that of its closo-counterpart 1. Water-solubilities of sugar modified nido-types 18 and 19 were about 1000 times higher than those of their closo-counterparts 5 and 6 . Cytotoxicities of the nido-types (17 and 19) were about 10 times lower than those of the corresponding closo-counterparts (1 and 6, respectively). Cellular uptake of the nido-types (17 and 19) was in the level similar to that of the closo-counterparts (1 and 6, respectively), although it is often believed that cellular uptake of hydrophilic carboranes (nido-forms) is much lower than that of lipophilic closo-carboranes.
  • Hitomi Suzuki, Toyomi Takeuchi, Tadashi Mori
    1997 Volume 70 Issue 12 Pages 3111-3115
    Published: 1997
    Released: June 20, 2006
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    A combination of nitrogen dioxide and water has been found to provide a new agent for the transformation of various alkyl methyl ethers 1 (R = Me) to carbonyl compounds 2 under mild conditions. The oxidation can be achieved successfully in dichloromethane, but hexafluoro-2-propanol was found to be most satisfactory as the solvent. The reaction was generally clean, and simple evaporation gave the expected oxidation product 2 in moderate to good yield. In the presence of ozone, but without water, the similar oxidation was observed only after prolonged reaction time, suggesting that some initial minor reaction with a strong oxidant, possible nitrogen trioxide, afforded an acidic promoter, which then worked as a catalyst similar to that involved in the reaction with a nitrogen dioxide and water system.
  • Motohiro Sonoda, Fumitoshi Kakiuchi, Naoto Chatani, Shinji Murai
    1997 Volume 70 Issue 12 Pages 3117-3128
    Published: 1997
    Released: June 20, 2006
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    To obtain further insight into the new ruthenium-catalyzed reaction of carbon–hydrogen bonds in aromatic ketones with olefins, the effect of various substituents at the aromatic ring is examined. Reaction of o-methylacetophenone with triethoxyvinylsilane (2) in the presence of [Ru(H)2(CO)(PPh3)3] (3)as the catalyst gave the 1 : 1 addition product in quantitative yield. Similarly, the ketone having an o-CF3 group gave the coupling product 9 in 92% yield. However, ortho substituents such as OMe, F, and CN, seem to react with and kill the catalyst so that no efficient reaction was attained. In the cases of the reactions of p-methoxy- and p-fluoroacetophenones with 2, the corresponding 1 : 2 addition products were obtained as the major products. In the cases of m-substituted acetophenones, two different C–H bonds at the ortho positions are available. The C–C bond formation preferentially occurred at the sterically less congested positions. Exceptions are the reactions of m-methoxy- and m-fluoroacetophenones, in which the C–C bond formation took place preferentially at the more congested position. This may be due to the coordination of oxygen or fluorine atom to ruthenium. The factors controlling these selectivities are discussed.
  • Isao Shiihara
    1997 Volume 70 Issue 12 Pages 3129-3136
    Published: 1997
    Released: June 20, 2006
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    This paper concerns the hardening mechanism of urushi lacquer. The author wished to propose an entirely new mechanism for the room-temperature hardening of urushiol in this natural resin. An investigation of the unit reactions correlated to the mechanism indicated that the catechol moiety of urushiol and metalhydroxides play an important role in hardening.
    According to the results, the structure of one component of urushiol as “acetone powder”, obtained from raw urushi sap, was clearly determined. On this basis, it is disclosed that the polymerization of urushiol does not depend on the opening of the sesquiterpene double bond, but is mainly associated with a new type of inorganic ionomer bonding, such as silanolate and carbohydroperoxide–calcium hyroxide, –magnesium hydroxide or –other metal hydroxide combinations’ hydrogen bonding bridges with the urushiol matrix.
  • Hisashi Tanaka, Akiko Kobayashi, Hayao Kobayashi
    Type: Accounts
    Subject area: AI
    1997 Volume 70 Issue 12 Pages 3137-3152
    Published: 1997
    Released: June 20, 2006
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    A series of cation radical salts of bis(ethylenedithio)tetrathiafulvalene (ET) and bis(ethylenedithio)tetraselenafulvalene (BETS) as donors and bis(dithiosquarato)metalate ([M(dts)2]n) as anions were synthesized. The electrical resistivities of most of these salts ((BETS)2[Pd(dts)2] (1), (BETS)2[Pd(dts)2]·2(1,1,2,2-TCE) (2) (1,1,2,2-TCE = 1,1,2,2-tetrachloroethane), (BETS)[Au(dts)2] (4), (ET)2[Pd(dts)2] (5), (ET)2[Pt(dts)2] (6), and (ET)[Au(dts)2] (7)) were semiconductive. However, one of the BETS salts with [Pd(dts)2], whose donor : anion ratio was 5 : 1. (BETS)x[Pd(dts)2] (x ≈ 5.0) (3), showed a metallic behavior down to 4 K. Although the crystal structure of these semiconducting salts was a kind of mixed stacks, many short contacts within the sum of the van der Waals radii were seen between chalcogens of the donors, and between chalcogens of the donor and anion. In addition, four terminal oxygen atoms of bis(dithiosquarato)metalate anion had C–H···O hydrogen bonds with terminal ethylene groups of ET and BETS, which was one of the factors determining the conformation of the terminal ethylene groups in these crystals.
  • Masaki Matsui, Ritsu Kawase, Kazumasa Funabiki, Hiroshige Muramatsu, K ...
    1997 Volume 70 Issue 12 Pages 3153-3158
    Published: 1997
    Released: June 20, 2006
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    4-Perfluoroalkylsulfonyl (RfSO2)-substituted azo nonlinear optical chromophores (NLOphores) showed enhanced second-order nonlinear coefficients (d33) and improved relaxation behavior compared with the corresponding nitro compound (Disperse Red 1 (DR 1)) in both doped poly(methylmethacrylate) (PMMA) and pendanted methylmethacrylate (MMA) copolymer.
  • Hidekatsu Yokoyama, Toshiyuki Sato, Hiroaki Ohya-Nishiguchi, Hitoshi K ...
    1997 Volume 70 Issue 12 Pages 3159-3162
    Published: 1997
    Released: June 20, 2006
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    Microelectrode-detected ESR (MEDESR) spectroscopy is a technique that is employed to observe magnetic resonance on the basis of an impedance change of electrodes. The characteristics of MEDESR for nitroxide radicals in electrolyte solutions were analyzed. MEDESR signals were obtained at zero bias-current, suggesting that modulation of the bias-current derived from ESR would not generate MEDESR signals. A good linear relationship between the MEDESR signal intensity and the applied power over a range of up to 150 mW was obtained. The frequency characteristics of the magnetic field modulation indicated that a simple thermal phenomenon would not cause an impedance change in MEDESR. When the radical was distributed on only the electrode surface, no signals were detected. The MEDESR spectra of a nitroxide solution, located outside the electrolytic cell, was detectable. These findings suggest that since MEDESR signals are irrelevant to the radicals in an electrical double layer, they are derived from some changes in the microwaves in the whole resonator. It is speculated, however, that the detecting mechanism of MEDESR is not a simple process of rectifying detection of a microwave change by resonant absorption like in conventional ESR, because the signal intensity of MEDESR is proportional to the irradiation power, and not to the square root as in the conventional ESR.
  • Hiroaki Okamoto, Hiroshi Murai, Shunsuke Takenaka
    1997 Volume 70 Issue 12 Pages 3163-3166
    Published: 1997
    Released: June 20, 2006
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    This paper describes the liquid-crystalline properties of alkyl 4-[2-(perfluorooctyl)ethoxy]benzoates (1) and bromo (2) and nitro (3) substituted compounds. For 1, the lower members show a smectic A phase; also the smectic A-isotropic transition temperatures and the latent heats decrease with increasing the carbon number of the hydrocarbon chain. An X-ray examination indicated that the smectic A phase has an interdigited arrangement of molecules. The results are discussed in terms of inter- and intra-layer fluorophilic interactions around the perfluorooctyl groups.
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