Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 85 , Issue 10
Showing 1-11 articles out of 11 articles from the selected issue
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  • Ichiro Hayakawa, Takuma Takemura, Emi Fukasawa, Yuta Ebihara, Natsuki ...
    2012 Volume 85 Issue 10 Pages 1077-1092
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: September 29, 2012
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    The total synthesis of auripyrones was achieved by using a novel aldol-type reaction of γ-pyrone as a key step. From this synthetic work, we have established the stereostructure and absolute configuration of auripyrone B. Furthermore, the cytotoxicities of auripyrones against a panel of 39 human cancer cell lines (termed JFCR39) at the Japanese Foundation for Cancer Research were investigated. The patterns of the differential cytotoxicities of auripyrones were COMPARE negative, suggesting that they inhibit cancer cell proliferation through a novel mechanism.
 
  • Kazuaki Fukushima, Hideo Iwahashi, Morimitsu Nishikimi
    2012 Volume 85 Issue 10 Pages 1093-1101
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: September 29, 2012
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    The process of protein synthesis occurs in the ribosome and is an essential feature of life. The exact reaction mechanism for peptide bond formation in the peptidyl transferase center of the ribosome is, however, still unknown. We calculated a stepwise mechanism of peptide bond formation, which is catalyzed by proton shuttles through cyclic hydrogen bonds, using the ONIOM (B3LYP/6-31G(d,p):Amber) method. In order to investigate the steric and electronic effects of the ribosomal environment on the reaction, we compared the geometries and energies of two model systems obtained either by ONIOM (B3LYP/6-31G(d,p):Amber) calculations or by cluster model calculations using the B3LYP/6-31G(d,p) level of theory. The results indicate that a steric effect of the ribosomal environment destabilizes the two transition states of the peptide bond formation, but that an electronic effect of the ribosomal environment as well as the catalytic shuttling of protons lowers the activation energy for the first step of the reaction.
  • Hitoshi Kumagai, Yoshiyuki Sakamoto, Satoshi Kawata, Shinichi Matsunag ...
    2012 Volume 85 Issue 10 Pages 1102-1111
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: October 10, 2012
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    We report on the synthesis, single-crystal structures, and properties (IR, UV–vis, ESR, and TG) of a series of coordination polymers employing R4-terephthalate dianion (R4-benzenedicarboxylate dianion, R4-bdc2−: R = H, F, Cl, Br) in which halogen atoms are systematically changed and 4,4′-bipyridine (4,4′-bpy) as cobridging ligands. These compounds are synthesized under the same conditions and all display octahedral metal coordination environments. A one-dimensional coordination polymer, [Mn(µ-4,4′-bpy)(H2O)4](H4-bdc) (1) consists of Mn(II) and 4,4′-bpy was obtained by reaction of Mn(II), terephthalate and 4,4′-bpy. Uncoordinated terephthalate acts as not only counter ion but also linker to form a three-dimensional network by hydrogen-bonding and π–π interactions. When halogen atoms are introduced to a benzene ring, layers of square-grid of octahedral Mn(II) ions are obtained for [Mn(µ-F4-bdc)(µ-4,4′-bpy)(H2O)2] (2), [Mn(µ-Cl4-bdc)(µ-4,4′-bpy)(H2O)2] (3), and [Mn(µ-Br4-bdc)(µ-4,4′-bpy)(H2O)2] (4). One of the major differences of the structures is hydrogen-bonding interactions between layers. This major difference is due to the different ionic radii of halogen atoms attached to benzene rings of the ligand to give different crystal packing. Compounds 24 exhibit different thermal behavior. While the XRD pattern of 2 indicates structural change upon hydration/dehydration, XRD patterns of 4 are not globally changed in these processes.
  • Tomoyuki Mizutani, Masaru Jinguji, Hiroshi Yamataka
    2012 Volume 85 Issue 10 Pages 1112-1119
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: September 29, 2012
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    The denitrogenation reactions of fifteen differently substituted vinyl diazonium (ethenediazonium) ions were examined by MO method at MP2/6-31G*. The parent vinyl diazonium ion (1, CH2=CH–N2+) was shown to initially give the H-bridged cation via the anti-H migration transition state (TS) or the syn-H migration TS. The relative barrier for the two TSs is very small, being 1.0 kcal mol−1 favoring the anti-H migration TS in free energy. The primary open cation is located on a very shallow minimum, and is 4.4 kcal mol−1 less stable than the bridged cation in free energy. The reactions of Me- and Ph-substituted vinyl diazonium ions showed characteristic features depending on the substituent. Molecular dynamics simulations for the reactions of 1 revealed that trajectories from the reactant state mostly gave the bridged cation as expected from the MO result, but there were trajectories that directly led to the open cation without H-participation, a clear manifestation of a dynamics effect. A dynamics effect on the relative population of the bridged versus the open cation is also presented.
  • Hideo Enozawa, Takeshi Takahashi, Tohru Nishinaga, Tadashi Kato, Masas ...
    2012 Volume 85 Issue 10 Pages 1120-1137
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: October 10, 2012
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    Multifunctional dodecadehydrotris(tetrathiafulvaleno)[18]annulenes 1b1d, which have six peripheral butylthio substituents or six ester substituents, were synthesized together with the corresponding [12]annulene 2c. The [18]annulenes 1b1d easily formed stacked dimers and higher oligomers in solution via nanoscopic phase separation among the π-frame, ester or alkylthio substituents, and inner sphere to show solvatochromism and thermochromism. Furthermore, the strong self-aggregation of their oxidized radical cations in solution resulted in electrochromism depending on the formation of various types of mixed-valence states and π-dimers. Interestingly, self-aggregation of the [18]annulenes 1b1d in amphiphilic media such as THF–H2O either produced fibrous structures in the case of the hexabutylthio derivative 1b and hexabutyl ester 1c or resulted in the temperature hysteresis of the color, UV–vis absorptions, and 1H NMR signals obtained in solution in the case of the hexaoctyl ester 1d which forms no fiber and precipitate under similar conditions. It is noted that fibers of the hexabutyl ester 1c can be aligned in a magnetic field using the large diamagnetic response of the [18]annulene frame for the driving force. A small difference in the substituents of 1b1d causes a remarkable change in either their solvato- and electrochromism or nanostructure formation of 1b1d based on the self-assembling nature both in solution and in the solid state.
  • Marlon Martínez-Reina, Eliseo Amado-González, Yonny Maur ...
    2012 Volume 85 Issue 10 Pages 1138-1144
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: October 10, 2012
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    The extraction of toluene from hydrocarbons (hexane, heptane, and cyclohexane) was analyzed by liquid extraction with 1-ethyl-3-methylimidazolium ethylsulfate [EMim][EtSO4] ionic liquid, as a solvent. The experimental liquid + liquid equilibrium (LLE) data were determined at T = 308.15 K and atmospheric pressure. Selectivity and distribution coefficient, derived from the tie-lines, were used to determine the ability of [EMim][EtSO4] as solvent for the separation of toluene from its mixtures with alkanes and cycloalkane. The degree of consistency of the experimental LLE data was ascertained using the Othmer–Tobias equation. The experimental data for LLE of the ternary systems were correlated with the nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) thermodynamic models.
  • Harsh Kumar, Chanda Chadha
    2012 Volume 85 Issue 10 Pages 1145-1154
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: October 10, 2012
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    Densities, ρ, and speeds of sound, u, of cyclopentane with 2-methyl-1-propanol, 3-methyl-1-butanol, and 2-methyl-2-butanol binary liquid mixtures have been measured over the whole composition range at atmospheric pressure at temperatures: 288.15, 298.15, and 308.15 K. Excess molar volumes VmE, isentropic compressibility κS, and their excess counterpart excess isentropic compressibility KS,mE have been calculated from experimental densities and speeds of sound. Apparent molar volume, Vφ,i partial molar volume, Vi, and apparent molar compressibilities have been calculated from the experimental density and speeds of measurements.
  • Keitaro Yoshihara, Yoshiki Takatori, Yoshizumi Kajii
    2012 Volume 85 Issue 10 Pages 1155-1159
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: October 10, 2012
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    We report water aerosol formation upon irradiation of wet air with a KrF laser at 248 nm. It occurred at temperatures ranging from 0 to 50 °C and at relative humidity values from ca. 10% to 100%. Aerosols were detected either by light scattering or by differential mobility analyses, and particle growth from 10 nm to sub-micrometers was observed. Photodissociation of oxygen was proposed as the initial step of the reactions leading to formation of the final stable molecule of hydrogen peroxide as a nucleus with a low vapor pressure. Simulations of the chemical kinetics by considering wet air revealed that the amount of the final product could be controlled by laser operational conditions such as laser repetition rates and pulse energies. KrF laser light can reach a few kilometers in the atmosphere owing to a small absorption cross section of oxygen and yet can produce water aerosol.
  • Keiko Kihara, Takayoshi Suzuki, Masakazu Kita, Yukinari Sunatsuki, Mas ...
    2012 Volume 85 Issue 10 Pages 1160-1166
    Published: October 15, 2012
    Released: October 15, 2012
    [Advance publication] Released: October 10, 2012
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    A series of cobalt(III) complexes containing 2-cyanoethylphosphines, [Co(Me2dtc)2{P(CH2CH2CN)nPh3−n}2]BF4 {Me2dtc: N,N-dimethyldithiocarbamate; n = 1 (1), 2 (2), and 3 (3)} have been prepared, and their molecular structures in the crystals and in solution have been characterized. X-ray analysis revealed that all complexes isolated as single-crystals were the trans-isomers. The Co–P bond lengths for the 2-cyanoethylphosphines in complexes 13 are almost invariant to the number of 2-cyanoethyl substituent groups. Unlike related complexes with other monodentate P-donor ligands, complexes 13 in solution showed dissociation and isomerization equilibriums, which were achieved immediately after dissolving the crystals. These characteristic features of the complexes would result from the weak σ-donor and π-acceptor abilities of 2-cyanoethylphosphines. Furthermore, mixing of complex 1 and NaN3 in acetonitrile gave cis-[Co(Me2dtc)2(N3){P(CH2CH2CN)Ph2}] quantitatively, and refluxing the mixture resulted in the phosphine–tetrazolate complex, [Co(Me2dtc)2(Ph2PCH2CH2CN4-κ2P,N1)] (4).
  • Przemysław Wyrebek, Stanisław Ostrowski
    2012 Volume 85 Issue 10 Pages 1167-1174
    Published: October 15, 2012
    Released: October 15, 2012
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    meso-Tetrakis(pentafluorophenyl)porphyrin reacts at higher temperature with unstable iminonitriles (R–C≡N+–N–Ar), affording pyrazoline-fused chlorins, according to dipolar [3 + 2]-cycloaddition pathway. The respective iminonitriles were in situ generated from the corresponding functionalized α-halogenohydrazine derivatives by 1,3-elimination of HX in the presence of base (NEt3, DABCO). This method allows synthesis of very attractive moieties which may be of potential use as sensitizers in photodynamic therapy (PDT).
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