Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 84 , Issue 10
Showing 1-20 articles out of 20 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for Young Chemists for 2008
  • Makoto Yamashita
    2011 Volume 84 Issue 10 Pages 983-999
    Published: October 15, 2011
    Released: October 15, 2011
    [Advance publication] Released: September 27, 2011
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    A series of anionic boron compounds, possessing a polarized boron–metal bond, were synthesized and structurally characterized. Detailed analyses of these boryl anions using NMR spectroscopy, X-ray crystallography, reactivity with electrophiles, and DFT calculations revealed that these compounds have anionic and nucleophilic character on the boron center in contrast to conventional boron-containing molecules with a Lewis acidic character. Some applications of boryl anions toward organic synthesis, organometallic chemistry, and main group chemistry are also described.
    A series of anionic boron compounds, possessing a polarized boron–metal bond, were synthesized and structurally characterized. Detailed analyses of these boryl anions using NMR spectroscopy, X-ray crystallography, reactivity with electrophiles, and DFT calculations revealed that these compounds have anionic and nucleophilic character on the boron center in contrast to conventional boron-containing molecules having a Lewis acidic character. Some applications of boryl anions toward organic synthesis, organometallic chemistry, and main group chemistry are also described. Fullsize Image
The Chemical Society of Japan Award for Young Chemists for 2007
  • Ryu Abe
    2011 Volume 84 Issue 10 Pages 1000-1030
    Published: October 15, 2011
    Released: October 15, 2011
    [Advance publication] Released: September 27, 2011
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    Photocatalytic water splitting using semiconductor materials has attracted considerable interest due to its potential for clean production of H2 from water by utilizing abundant solar light. The developments of water-splitting systems that can efficiently use visible light have been a major challenge for many years in order to realize efficient conversion of solar light. We have developed a new type of photocatalysis system that can split water into H2 and O2 under visible light irradiation, which was inspired by the two-step photoexcitation (Z-scheme) mechanism of natural photosynthesis in green plants. In this system, the water-splitting reaction is broken up into two stages: one for H2 evolution and the other for O2 evolution; these are combined by using a shuttle redox couple (Red/Ox) in the solution. The introduction of a Z-scheme mechanism reduces the energy required to drive each photocatalysis process, extending the usable wavelengths significantly (≈660 nm for H2 evolution and ≈600 nm for O2 evolution) from that in conventional water splitting systems (≈460 nm) based on one-step photoexcitation in single semiconductor material.
    A novel photocatalytic system that splits water into H2 and O2 under visible light was realized using a two-step photoexcitation system composed of a shuttle redox couple and two different semiconductor photocatalysts. Fullsize Image
BCSJ Award Article
  • Yuya Tsujimoto, Machiko Ie, Yasunari Ando, Taiki Yamamoto, Akihiko Tsu ...
    2011 Volume 84 Issue 10 Pages 1031-1038
    Published: October 15, 2011
    Released: October 15, 2011
    [Advance publication] Released: September 15, 2011
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    In a vortex generated by mechanical rotary stirring in an optical cell, DNA molecules in pure water temporarily align helically to the spiral flow, and dynamically display strong induced circular dichroism (CD) and linear dichroism (LD) responses. Although a sample solution without stirring provided the characteristic CD spectral pattern of DNA, an entirely different macroscopic CD spectral pattern with a much larger intensity and LD spectrum appeared upon mechanical rotary stirring of the sample solution. Clockwise (CW) and counterclockwise (CCW) stirring resulted in mirror-image CD spectral profiles and virtually the same LD profiles with different intensities. The CW stirring of the sample solution in LD spectroscopy always resulted in larger spectral intensities than CCW stirring, but the differences became negligible upon addition of NaCl or ethidium bromide. The observed CD and LD responses of the stirred sample solution decreased simultaneously as the double-stranded structure denatures with increasing temperatures. The results obtained in this study indicate that DNA, when it forms a double-stranded structure, can effectively align in the vortex flows, and show hydrodynamic preference to a right-handed vortex than to a left-handed vortex.
    In a vortex generated by mechanical rotary stirring in an optical cell, DNA molecules in pure water temporarily align helically to the spiral flow, and dynamically display strong induced circular dichroism and linear dichroism responses. DNA, when it forms a double-stranded structure, can effectively align in the vortex flows, and shows hydrodynamic preference for a right-handed vortex over a left-handed vortex. Fullsize Image
 
  • Jun Li, Kazunari Yoshizawa
    2011 Volume 84 Issue 10 Pages 1039-1048
    Published: October 15, 2011
    Released: October 15, 2011
    [Advance publication] Released: October 06, 2011
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    A reaction mechanism for the hydrogenation of CO2 to formate catalyzed by an Ir(III)–pincer trihydride complex has been investigated with density functional theory calculations. Two routes for the formation of formate were considered: (I) the insertion of CO2 into the Ir–H bond with the assistance of the metal center, and (II) the direct addition of hydride to CO2 via nucleophilic attack. Route II is energetically more favorable than route I. Molecular orbital and natural bond orbital analyses showed that this trihydride complex consists of two kinds of hydrides with distinct Ir–H bond properties, and the hydride in the plane vertical to the pyridine moiety is highly active. The whole catalytic cycle for CO2 hydrogenation to formate is exothermic by 30.3 kcal mol−1, and the rate-limiting step is the regeneration of the active complex, which involves a barrier of 15.6 kcal mol−1. The theoretical results are in good agreement with and give a reasonable explanation to the experimental observations. Moreover, the results imply that the type of a metal–hydride bond might determine which route the CO2 insertion takes, route I or route II.
  • Hirotaka Kojima, Takehiko Mori
    2011 Volume 84 Issue 10 Pages 1049-1056
    Published: October 15, 2011
    Released: October 15, 2011
    [Advance publication] Released: October 06, 2011
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    The herringbone structure is a representative molecular packing in organic semiconductors, but there are some modifications with largely different dihedral angles ranging from 40 to 130°. Dihedral angle θ dependence of the transfer integrals is systematically investigated on the basis of the molecular orbital calculations for various organic semiconductors including pentacene, picene, oligothiophene, fused thiophene, tetrathiafulvalenes (TTF), and benzothienobenzothiophene (BTBT). In the conventional organic semiconductors such as pentacene and oligothiophene, the transfer integral is a monotonously decreasing function of θ starting from the stacking geometry, and smaller θ provides more two-dimensional bands. When the molecules are slipped along the molecular long axis D, these compounds show characteristic oscillating structure of the transfer integrals depending on D, which is called D-modulation. Contrarily, TTF derivatives show oscillating structure of the transfer integrals depending on θ (θ-modulation) due to interaction at the side position. BTBT exhibits a pattern much different from the conventional organic semiconductors, and a considerable magnitude of transfer integrals is expected in the large θ region. These systematic investigations demonstrate that the θ-dependence of the charge transport largely depends on the original molecular orbital symmetry.
  • Taichi Kano, Akihiro Yamamoto, Sunhwa Song, Keiji Maruoka
    2011 Volume 84 Issue 10 Pages 1057-1065
    Published: October 15, 2011
    Released: October 15, 2011
    [Advance publication] Released: October 06, 2011
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    Catalytic asymmetric synthesis of various isoxazoline-N-oxides having a tetrasubstituted carbon has been accomplished by asymmetric phase-transfer conjugate addition of bromomalonate to nitroolefins and subsequent ring-closing O-alkylation. The obtained isoxazoline-N-oxide was readily converted to the corresponding oxime, isoxazoline, and lactam without loss of optical purity.
  • Tsuyoshi Nitami, Akiko Sekine, Hidehiro Uekusa, Yuji Ohashi
    2011 Volume 84 Issue 10 Pages 1066-1074
    Published: October 15, 2011
    Released: October 15, 2011
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    When a crystal of [(S)-1-cyclohexylethylamine]bis(dimethylglyoximato)[(S)-1-(ethoxycarbonyl)ethyl]cobalt(III) was irradiated with a halogen lamp, the absolute configuration of the (S)-1-(ethoxycarbonyl)ethyl group gradually changed from S to R with retention of the single crystal form. After 24 h exposure, the change became within experimental error and the S:R ratio of the 1-(ethoxycarbonyl)ethyl group was found to be 18:82 by X-ray crystal structure analysis. The crystals with the (R)- and (racemic)-1-(ethoxycarbonyl)ethyl groups instead of the (S)-enantiomer have isomorphous structures to the crystal with the (S)-enantiomer. Both of the crystals were also changed to the same structure as that with the (S)-enantiomer on exposure to the halogen lamp. This marvelous ratio of 18:82 was clearly explained with the shape of the reaction cavity for the photoreactive 1-(ethoxycarbonyl)ethyl group in each crystal structure. A pseudo-isomorphous crystal of the complex with the (S)-enantiomer was obtained under the same conditions but it contains a water molecule as solvate. The (S)-1-(ethoxycarbonyl)ethyl group in the crystal gradually changed to the disordered racemate with retention of the single-crystal form. The different reaction pathway between the pseudo-isomorphous crystals with and without a water molecule was explained with not only the size but also the shape of the reaction cavity for the photoreactive group.
  • Yusuke Fuchiwaki, Hidenori Nagai, Masato Saito, Eiichi Tamiya
    2011 Volume 84 Issue 10 Pages 1075-1081
    Published: October 15, 2011
    Released: October 15, 2011
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    Flow-through PCR devices for performing rapid and small-volume DNA amplification on a single chip have attracted great interest. Flow-through DNA amplification was performed by moving PCR solution as a liquid plug through three individual temperature zones. Since precise control of the temperature setting is the most important technique for successful DNA amplification, real-time temperature analyses of the moving fluid were investigated using a polyolefin pressure-sensitive adhesive (PPSA) film to cover the microchannel. The temperature profile at 20 °C during annealing phase was the closest to the recommended conditions for PCR compared to the profile from 55 to 20 °C, and it showed the highest amplification of the tested regimes. The microchannel design was optimized using an infrared (IR) thermal imager to significantly increase the fluorescence intensity of the amplified products. A flow time of five to six seconds per cycle resulted in a temperature profile close to the recommended thermal gradient. These studies resulted in effective findings for simple and rapid amplification by moving a PCR solution as liquid-plug on a single chip.
  • Saori Takahashi, Mami Murase, Hiroaki Hagiwara, Naohide Matsumoto, Mas ...
    2011 Volume 84 Issue 10 Pages 1082-1089
    Published: October 15, 2011
    Released: October 15, 2011
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    Three SmIII complexes with tripod heptadentate N7 ligands containing three imidazole groups, [Sm(H3L2-Me)(ac)](ClO4)2·2MeOH·H2O (1), [Sm(H3L2-Me)(ac)](ClO4)2·2EtOH (2), and [Sm(H3L4-Me)(ac)](ClO4)2·MeOH (3), were synthesized and the crystal structures were determined, where H3L2-Me and H3L4-Me are the 1:3 condensation products of tris(2-aminoethyl)amine and either 2-methyl-4-formylimidazole and 4-methyl-5-formylimidazole, respectively, and ac denotes acetate ion. Each SmIII ion is coordinated by a tripod heptadentate N7 ligand and two oxygen atoms of the acetate ion. Due to the screw coordination arrangement of the achiral tripod ligand to the SmIII ion, the complex-cation [SmIII(H3L2- or 4-Me)(ac)]2+ gives Δ- and Λ-enantiomorphs. In compounds 1 and 2, two adjacent [Sm(H3L2-Me)(ac)]2+ species with the same chirality are linked by an intermolecular imidazole···acetate hydrogen bond to form a homochiral 1D chain structure. Adjacent chains with the same chirality are stacked to give a conglomerate crystal in 1, while adjacent chains with opposite chiralities are stacked to give a racemic crystal in 2. In compound 3, two adjacent [Sm(H3L4-Me)(ac)]2+ species with the opposite chiralities are doubly bridged by two intermolecular imidazole···acetate hydrogen bonds to form a heterochiral dimer and the adjacent dimers are connected by ClO4 ion through the hydrogen bonds to form a racemic crystal.
  • Natsuko Kojima, Shigenobu Hayashi
    2011 Volume 84 Issue 10 Pages 1090-1095
    Published: October 15, 2011
    Released: October 15, 2011
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    We have studied the state of adsorbed dichloromethane molecules not removed by evacuation in several H-type zeolites, ZSM5, mordenite, β, and Y, by means of solid-state NMR. The amount of undesorbed dichloromethane was determined by quantitative analysis of 1H MAS NMR spectra. The strength and the amount of Brønsted acid sites could not explain the amount of the undesorbed dichloromethane. The channel size is the most probable to determine the amount. The 1H and 13C MAS NMR spectra as well as the 2H static NMR spectra demonstrated that undesorbed dichloromethane is rather mobile.
  • Yuki Takayama, Midori Taketa-Sato, Hirofumi Komori, Kumiko Morita, Su- ...
    2011 Volume 84 Issue 10 Pages 1096-1101
    Published: October 15, 2011
    Released: October 15, 2011
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    Cytochrome c3 possesses four hemes in a compact configuration and exhibits extremely low reduction potentials. Besides the well-characterized factors contributing to the reduction potentials, the aromatic rings have been suggested to be involved. To elucidate its mechanism, the effect of mutations at conserved and noncoordinated aromatic residues on the reduction/oxidation properties of heme irons was investigated on the basis of crystal structures, NMR spectra of coordinated His, and reduction potentials. Phe20 parallel to heme 1 is the most conserved residue. On its mutation, the change in each coordination structure was subtle in the crystal structures despite of significant changes in the NMR spectra and reduction potentials. Significant increases in the reduction potentials of heme 1 led to the conclusion that the aromatic ring of Phe20 stabilizes the polarization of the π-electron density induced by the oxidized iron in the same heme. Furthermore, the reduction potential of heme 2 was also affected by the mutation at Phe20, revealing that the electrostatic interaction between the π-electron system of the porphyrin and a distant iron contributes to the iron reduction potential. This kind of interaction provides new insight into the role of the heme architecture in regulation of the reduction potentials.
  • Yen-Ju Tseng, Zhi-Hong Wen, Chi-Hsin Hsu, Chang-Feng Dai, Jyh-Horng Sh ...
    2011 Volume 84 Issue 10 Pages 1102-1106
    Published: October 15, 2011
    Released: October 15, 2011
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    Two new metabolites, crassumolides H and I (2 and 3), and crassumolide G (1) which was discovered for the first time from natural sources, were isolated from the ethyl acetate extract of a Taiwanese soft coral Lobophytum crassum, along with three known metabolites 46. The structures of metabolites 13 were elucidated by extensive spectroscopic analysis and comparison of the NMR data with those of known compounds. Compounds 13 were found to inhibit the accumulation of the pro-inflammatory iNOS and COX-2 proteins at 10 µM in LPS-stimulated RAW264.7 marcophage cells.
  • Atsushi Sato, Hulin Tai, Shigenori Nagatomo, Kiyohiro Imai, Yasuhiko Y ...
    2011 Volume 84 Issue 10 Pages 1107-1111
    Published: October 15, 2011
    Released: October 15, 2011
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    We determined the oxygen (O2) binding properties of the individual subunits of intact human adult hemoglobin (Hb A) through the combined use of 1H NMR and conventional spectrophotometric methods. We found that the O2 affinities of the α and β subunits of Hb A are almost indistinguishable in the absence of an allosteric effector, inositol hexaphosphate (IHP), and lower by factors of ≈8.4 and ≈10, respectively, in the presence of IHP at pH 7.40, as judged from the estimated P50 values, which represent the partial O2 pressure required to achieve 50% oxygenation of the individual subunits. These results demonstrated that the binding of IHP to the protein resulted in remarkable enhancement of the degree of nonequivalence in functional properties between the constituent subunits, which could be relevant to its cooperative ligand binding. This finding provides novel insights for elucidation of the molecular mechanisms responsible for the cooperativity in this allosteric protein.
  • Hossein Naeimi, Khadijeh Rabiei
    2011 Volume 84 Issue 10 Pages 1112-1117
    Published: October 15, 2011
    Released: October 15, 2011
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    In this research, rapid and efficient preparation of 1,3-diaryl-2,2-dichloroaziridines through the reaction of Schiff base compounds with dichlorocarbene yielded in situ in the presence of cetyltrimethylammonium bromide (CTAB) as phase-transfer catalyst under ultrasonic irradiation is described. The advantages of this reaction are very short reaction times, excellent product yields, simplicity of the method, and high purity of products.
  • Hideto Nakajima, Makoto Yasuda, Kenji Shimizu, Naomi Toyoshima, Yasuno ...
    2011 Volume 84 Issue 10 Pages 1118-1129
    Published: October 15, 2011
    Released: October 15, 2011
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    The control of photoluminescence wavelength is important for the design of emitting materials, and compounds bearing aryl–aryl bonds are considered to be useful candidates for the synthesis of these materials. However, the biaryl system lacks an efficient linkage of independent conjugated moieties because of a structure that, rather than planar, is made up of almost perpendicular dihedral angles due to steric effect. In this paper, we report a novel method to link independent π-systems in biaryl compounds. The oxy-substituents at the peri-position in 1-arylnaphthalene systems, which are biaryl compounds, showed interesting and unexpected photophysical properties of a bathochromic shift of emission. In particular, peri-OH-substituted arylnaphthalenes showed a large bathochromic shift that was induced by polarization based on intramolecular OH–aryl interaction. Quantum chemical (TDDFT) calculations accurately reproduced the large bathochromic shifts of peri-OH-substituted arylnaphthalenes. The through-space interaction between the peri-substituted OH and aryl groups generated an unexpected extended conjugation system. The substituting position of OH in 1-arylnaphthalenes is quite critical, because the hydroxy group mediates the independent π-systems to expand conjugation. Based on this concept, 1,3,5-tris(peri-hydroxynaphthyl)benzene had characteristic photophysical properties, giving an unexpected blue emission.
  • Jin Matsumoto, Yusuke Yoshinaga, Akiko Hamasaki, Tomohiro Kawasaki, To ...
    2011 Volume 84 Issue 10 Pages 1130-1132
    Published: October 15, 2011
    Released: October 15, 2011
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    Photosensitized nucleophilic additions of 2,5-dimethyl-2,4-hexadiene and 2,3-dimethyl-2-butene were performed in a microchannel reactor using phenanthrene and p-dicyanobenzene as a redox pair. The quantum yields for the formation of photo-NOCAS products were remarkably enhanced at lower temperatures. The exciplex formation disturbed the reaction at higher temperatures.
  • Ikuhide Fujisawa, Daiki Takeuchi, Ryo Kato, Kazutaka Murayama, Katsuyu ...
    2011 Volume 84 Issue 10 Pages 1133-1135
    Published: October 15, 2011
    Released: October 15, 2011
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    Resorcin[4]arene and tetramethylated resorcin[4]arene form complexes with L-carnitine, whose crystal structures were determined. Each complex contains two carnitine ligands in the asymmetric unit, each of which is incorporated into the cavity of the macrocyclic receptor through cation–π interactions between the trimethylammonium moiety of the ligand and π–rings of the receptor.
  • Satoshi Inagaki, Kenzo Onodera, Kensaku Tani, Yoshihiro Kubota
    2011 Volume 84 Issue 10 Pages 1136-1143
    Published: October 15, 2011
    Released: October 15, 2011
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    Various microwave-heated heterogeneous catalytic reactions can be accelerated by choice of the catalyst supports and solvents. In this work, heterogeneous Pd catalysts supported on ordered mesoporous carbon CMK-3 and related catalysts were prepared. In the presence of these catalysts, the effect of microwave heating on Pd-catalyzed Suzuki–Miyaura coupling as a probe reaction was investigated. The CMK-3 worked efficiently as a “carbon nanoflask” under microwave irradiation, especially in nonpolar solvents such as toluene and o-xylene with a lower ratio of dielectric constant (ε′) to dielectric loss (ε′′) (=tan δ).
  • Yukihisa Okumura, Satoshi Yabushita, Aya Watanabe
    2011 Volume 84 Issue 10 Pages 1144-1146
    Published: October 15, 2011
    Released: October 15, 2011
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    Giant lipid membrane vesicles (GVs) were immobilized onto the surface of Sephacryl S-1000 gel particles chemically modified to possess hydrophobic moieties. The immobilization was firm but not efficient. Strong preference of the immobilization for small lipid aggregates enabled their removal from GV preparation by repeated incubation with the gel.
  • Yukihisa Okumura, Yuuichi Iwata
    2011 Volume 84 Issue 10 Pages 1147-1149
    Published: October 15, 2011
    Released: October 15, 2011
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    Electroformation of giant vesicles (GVs) on the negative electrode of dc (static and pulsed) was identical to ac. The negative phase of ac mainly drives the formation. The mechanical oscillation of lipid had little effects. At higher frequency, electroformation with ac deteriorated, while dc pulses still yielded GVs.
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