Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Current issue
Displaying 1-15 of 15 articles from this issue
 
  • Hironori Izawa, Shota Ishisaka, Hiroyuki Saimoto, Shinsuke Ifuku
    2022 Volume 95 Issue 9 Pages 1289-1295
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    The effects of the physical properties of skin layers and substrates on drying-induced surface wrinkling are investigated with a system using chitosan films having polyion complex (PIC) skin layers. The PIC layers are fabricated with diverse anionic polymers having similar molecular weights on a chitosan (CS) film surface, and the films are dried. In all cases, surface wrinkles form but their sizes vary widely depending on the molecular structure. In particular, wrinkles formed with ligninsulfonate are much larger than those formed with the others. The skin layers differ significantly in surface hardness but not in thickness, indicating that wrinkle sizes induced by PIC skin layers are predominately determined by the hardness of the layers or by physical properties affected by hardness, such as shrinkage volume. The effects of the elastic moduli and shrinkage volume of the substrates are evaluated with higher molecular weight CS and surface-deacetylated chitin nanofiber composite CS films that have different elastic moduli but show very similar swelling–drying behaviors. The wrinkle sizes and skin layer thicknesses also suggest that wrinkle size in this system depends on the hardness of the skin layers or on the physical properties affecting the hardness.

  • Kenichi Kato, Nobuyoshi Seto, Koki Chida, Takeharu Yoshii, Motohiro Mi ...
    2022 Volume 95 Issue 9 Pages 1296-1302
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Rigid three-dimensional π-skeletons are useful building blocks for organic porous materials but only a few types of compounds are available as compared with a variety of planar building blocks. Herein, we report that hexa-aminated trinaphtho[3.3.3]propellane was readily prepared by a two-step reaction sequence from a non-functionalized propellane in moderate yield and was active toward condensation with boronic acids and aldehydes. Solvothermal condensation with terephthalaldehyde gave an amorphous polymeric solid with moderate BET surface area, different from precursor molecules. The solid displayed good adsorption capacities for hydrocarbon gases and vapors. Because of multiple CH/π interactions, the adsorption was efficient even at low-pressure for n-butane and larger alkanes, providing good selectivity over smaller alkanes.

  • Mengying Han, Shohei Tashiro, Takafumi Shiraogawa, Masahiro Ehara, Mit ...
    2022 Volume 95 Issue 9 Pages 1303-1307
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Developing catalysts comparable to natural enzymes that achieve only specific reactions has long been a key challenge in the field of molecular synthesis. Long-range olefin migration reactions have attracted great interest as molecular transformation reactions that can realize remote re-functionalization of a molecule with high atom economy. Herein we report that linear alkenyl alcohols of a certain chain length can chemically activate Pd centers precisely arranged in a porous metal-macrocycle framework (MMF), thereby promoting substrate-specific, catalytic long-range olefin migration reactions that produce aldehydes or ketones. Furthermore, MMF can be chemically activated by highly reactive alkenyl alcohol substrates, converting another olefinic substrate that normally would not react with nonactivated MMF into an olefin-migrated product at a high conversion. These reaction specificities are discussed in relation to the arrangement mode of the Pd active centers in the confined space.

CSJ Account
  • Makoto Komiyama
    2022 Volume 95 Issue 9 Pages 1308-1317
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    For these three years, COVID-19 has globally spread and caused enormous damage all over the world. Although vaccines served to reduce its infection, their effects are still limited mainly due to rapid and vigorous mutations of SARS-CoV-2 virus. In order to bring this pandemic under control, we must develop novel medicines which are easily administered when needed and very effective without undesired side-effects. In this account, the developments of specific medicines for COVID-19 are surveyed with the emphasis on the molecular mechanisms of their therapeutic actions. Most of them are inhibitors of enzymes, which are indispensable for the virus, but unnecessary for human beings. These inhibitors selectively hamper the critical steps for viral proliferation (viral entry to human cells, replication of RNA genome, production of viral proteins, and others). There have been several successful examples, which are already approved as medicines for the treatment of COVID-19. Unfortunately, however, few of them sufficiently satisfy all the requirements to overcome this unprecedented pandemic completely, and thus further innovation is necessary.

    Developments of specific medicines for COVID-19 are surveyed with emphasis on the molecular mechanisms of their therapeutic actions. Most of them are inhibitors of enzymes, which are responsible for the replication of RNA genome, production of viral proteins, or viral entry to human cells. Fullsize Image
     
 
  • Yoshiaki Nishijima, Saulius Juodkazis
    2022 Volume 95 Issue 9 Pages 1318-1324
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    We have demonstrated the coupling of metasurface resonance with a molecular vibration from weak to strong. Metal-insulator-metal (MIM) metasurfaces using various polymers as the insulator layer (I-layer) were fabricated and characterised. The strength of coupling between MIM metasurface and molecular absorbance in the I-layer of organic nano-film depends on the dipole mode of the molecular vibration and the molecular number density. In the case of strong coupling, when Rabi-splitting is observed at the molecular absorption band, the coupling efficiency reaches several percent of the particular molecular vibration modes in the volume below nanodisks of the MIM metasurface.

  • Joseph Y. M. Chan, Yusuke Okada, Satsuki Yoshida, Takahiro Kawata, Nag ...
    2022 Volume 95 Issue 9 Pages 1325-1331
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    A series of metal-free and metallo-diazaporphyrin analogues embedded with a 1,10-phenanthroline unit were synthesized and characterized. The molecular structure of the Ni(II) complex determined by single-crystal X-ray diffraction analysis confirmed its monocationic character in which the metal center adopts a typical square planar geometry binding with the pyrrole and phenanthroline nitrogen atoms. The spectroscopic and electrochemical studies, as well as molecular orbital calculations suggested that the metal complexes can be classified as 4nπ non-aromatic compounds.

Award Account
The Chemical Society of Japan Award for Creative Work for 2021
  • Kazuya Yamaguchi, Xiongjie Jin, Takafumi Yatabe, Kosuke Suzuki
    2022 Volume 95 Issue 9 Pages 1332-1352
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Our design strategies for multifunctional heterogeneous catalysts based on nanosized metal oxides and metal nanoparticles as well as the development of several novel dehydrogenative oxidation reactions unique to these heterogeneous catalysts are summarized in this review article. We established a methodology for the precise design of nanosized crystalline oxides in organic solvents and developed new reactions that can be realized only with heterogeneous catalysts designed by this method; for example, we realized oxidative amidation of primary alcohols and other substrates using O2 and NH3 by using nanocrystalline manganese oxides. We discovered the particular dehydrogenation abilities of Au, Pd, and their binary nanoparticles, and successfully developed several new reactions that effectively utilize them. Using designed supported Au nanoparticle catalysts, we have successfully developed various environmentally benign reactions involving dehydrogenation, such as formal amine oxygenation, cross dehydrogenative coupling, and flavonoid synthesis. Furthermore, dehydrogenative aromatization reactions with H2 production were realized using a Pd nanoparticle-based catalyst design. We believe that the reactions we have developed are environmentally benign and that the results of our research will have substantial practical implications in addition to academic ones, such as providing new methodologies for catalyst design and pioneering new reactions.

    We have designed multifunctional heterogeneous catalysts based on nano-sized metal oxides and metal nanoparticles. Using these multifunctional heterogeneous catalysts, several novel dehydrogenative oxidation reactions unique to the heterogeneous catalysts was successfully developed; for example, oxidative amidation of primary alcohols, formal α-oxygenation of amines, and acceptorless dehydrogenative aromatization of six-membered carbocyclic compounds. Fullsize Image
     
 
  • Risa Sawada, Masayuki Gon, Yoshiki Chujo, Ryo Inoue, Yasuhiro Morisaki
    2022 Volume 95 Issue 9 Pages 1353-1359
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Optically active V-shaped and X-shaped molecules consisting of stacked five-ringed para-phenylene-ethynylenes (PPEs) were prepared using planar chiral [2.2]paracyclophanes as chiral building blocks. Despite having the same absolute configurations, the V- and X-shaped molecules exhibited opposite circular dichroism (CD) and circularly polarized luminescence (CPL) signals. For example, the (Sp)-isomer of the V-shaped molecule and (Sp)-isomers of the X-shaped molecules exhibited negative and positive CPL emissions, respectively. Simulations using time-dependent density-functional theory calculations indicated that the lowest unoccupied molecular orbital (LUMO) of the V-shaped molecule in the S1 state was localized in one of the stacking PPEs, whereas the LUMOs of the two X-shaped molecules in the S1 state were delocalized in both PPEs via the [2.2]paracyclophane moieties. The theoretical results were reproduced and explained the CD and CPL behaviors well.

BCSJ Award Article
  • Ryosuke Masuda, Satoru Kuwano, Shohei Sase, Marco Bortoli, Andrea Mada ...
    2022 Volume 95 Issue 9 Pages 1360-1379
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Although much attention has been paid to chemical elucidation of the catalytic cycle of glutathione peroxidase (GPx), it has been hampered by instability of selenocysteine selenenic acid (Sec–SeOH) intermediates. In this study, not only chemical processes of the canonical catalytic cycle but also those involved in the bypass mechanism, including the intramolecular cyclization of a Sec–SeOH to the corresponding five-membered ring selenenyl amide were demonstrated experimentally by utilizing selenopeptide model systems in which reactive intermediates can be stabilized by a nano-sized molecular cradle. The resulting cyclic selenenyl amide exhibited higher durability under oxidative conditions than in the state of a Sec–SeOH, corroborating its role as the protective form of GPx. The cyclization of Sec–SeOHs of the Sec-Gly-Thr and Sec-Gly-Lys models, which mimic the catalytic site of isozymes GPx1 and GPx4, respectively, was found to proceed at lower temperature than in the Sec-Gly-Gly model, which corresponds to the generalized form of the tripeptides in the catalytic site of GPx. The role of the hydrogen-bond accepting moieties in the cyclization process was elucidated by DFT calculation. It was indicated that, if the selenocysteine centers are incorporated in appropriate microenvironments, the bypass mechanism can function efficiently.

    The protective bypass mechanism in the catalytic cycle of glutathione peroxidase (GPx), i.e., the cyclization of selenocysteine selenenic acids (Sec–SeOHs) to the corresponding cyclic selenenyl amides, was investigated using NMR-observable Sec–SeOHs modeling the tripeptides in the active site of GPx. Depending on the neighboring amino acid residue, the cyclization was found to proceed efficiently. Fullsize Image
     
 
  • Jian Luo, Hui Chen, Ran An, Xingguo Liang
    2022 Volume 95 Issue 9 Pages 1380-1388
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Preparation of adenylated DNA, which has wide applications, is a great challenge because the obtained AppDNA is usually quickly ligated to the 3′-OH at the nick. Here, by using an Aid-DNA with a mini-hairpin structure at its 3′ terminal, involving a 3–4-bp stem and a 3-nt loop, high adenylation yield (>90%) for most target sequences is obtained with no ligation by-products. The 5′ side of the Aid-DNA is complementary to the DNA to be adenylated, and forms a pseudo-nick after hybridization. T4 DNA ligase, the most popular ligase, can complete the adenylation. By investigating the effects of stem lengths, types of mismatched base pairs, and reaction conditions, we found that both a short stem and the mismatched base pair at 3′ end are essential to avoid ligation. More interestingly, the adenylation can be efficiently carried out even when another mismatched base pair flanks the 5′ side of the nick, and the ligation is completely inhibited. Thus, adenylation of a DNA becomes simple just by changing the Aid-DNA sequence at the 5′ side. This approach is also proved applicable for RNA adenylation, although the DNA ligase is used. Our finding is also helpful for understanding detailed mechanism of DNA ligation.

  • Karolina Lament, Jolanta Nieszporek, Wojciech Piasecki
    2022 Volume 95 Issue 9 Pages 1389-1395
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    This study aims at establishing how metal oxides (TiO2, Fe2O3, SiO2, and Al2O3) influence electrochemical activity of Fe2+ ions in solutions of different pH. Above pH 6.5 almost total uptake of Fe2+ ions from solution was reported for all oxides due to adsorption and oxidation of ferrous ions manifested by the reversal of the redox potential (Eh) trend. TiO2 and Fe2O3 revealed the strongest Fe2+ affinity and Al2O3 the weakest. X-ray photoelectron spectroscopy (XPS) indicated the transformation of precipitated Fe(OH)3 into FeOOH above pH 6.5. Square wave voltammetry (SWV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) have been used in experimental measurements applying the gold electrode. The changes in Ra (activation resistance of the Fe2+ electrooxidation) confirmed the beneficial effect of Fe2O3 and TiO2 on the rate of Fe2+ electrooxidation on the electrode. The linear relationship between the anodic peak current and the square root of the scanning rate proves that in the absence of oxides, the Fe2+ oxidation process is determined by the diffusion of the depolarizer to the electrode surface. In the presence of oxides, the relationships Ip = f (√v) are non-linear, and therefore the electrooxidation of Fe2+ ions is controlled by their adsorption on gold.

  • Yamato Fujihira, Hiroto Iwasaki, Yuji Sumii, Hiroaki Adachi, Takumi Ka ...
    2022 Volume 95 Issue 9 Pages 1396-1406
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Hydrofluorocarbons (HFCs) are widely used as cooling agents in refrigerators and air conditioners and as solvents in industrial processes. However, their application has been restricted by their high global warming potential. Thus, strategies for HFC decomposition and effective utilization are urgently required. Herein, we describe a method for the chemical transformation of two HFCs, viz. HFC-23 and HFC-125, based on the continuous-flow perfluoroalkylation of esters to synthesize the pharmaceutically and agrochemically vital trifluoromethyl and pentafluoroethyl ketones. The combination of a potassium base and a glyme solvent system is found to be the most effective. The proposed method is attractive for industrial use because it allows the consumption of a large volume of HFCs, promotes the synthesis of high-value medicinal compounds, and serves as an ideal alternative to the current HFC decomposition processes like thermal plasma treatment.

  • Hidetoshi Miyazaki, Katsumi Yamada
    2022 Volume 95 Issue 9 Pages 1407-1410
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Praseodymium oxide nanoparticle-embedded composite films were prepared using praseodymium nitrate and transparent urethane resin. The prepared films were further irradiated with ultraviolet (UV) light, and subsequently, their microstructure and optical properties were investigated. The color of the composite films turned from pale green (close to the precursor color) to reddish brown owing to UV irradiation. Pr6O11 particles were found to be present in the obtained films, and the particle size in the films increased upon increasing the UV irradiation time. The films obtained after UV irradiation showed absorption peaks at 444, 468, 483, 592, and 1020 nm, which were attributed to 3H43P2, 3P1, 3P0, 1D2, and 1G4, respectively, corresponding to the 4f-4f transition of Pr3+. The composite films exhibited photoluminescence with a peak at 605 nm corresponding to the 1D23H4 transition of Pr3+ up on excitation with 444 nm light.

  • Yoshiaki Nishijima, Saulius Juodkazis
    2022 Volume 95 Issue 9 Pages 1411-1418
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    The coupling between light and molecular vibrational modes is dependent on the efficiency of molecular absorption. Here, we demonstrate a method to control the coupling between molecular mid-infrared absorption/emission in the chemical fingerprinting spectral window and a metasurface using SiO2 as an absorber/emitter and CaF2 as a spacer to optimize the strength of coupling. The use of inorganic dielectric I-spacers in metal–insulator–metal (MIM) metasurfaces opens applications in narrow-band emitters for a mid-infrared spectral window at elevated temperatures (>350 °C), where polymer/organic I-spacers degrade.

  • Toshiki Ito, Masafumi Ueda, Masahiro Fujisaki, Aya Yoshimura, Takashi ...
    2022 Volume 95 Issue 9 Pages 1419-1427
    Published: September 15, 2022
    Released on J-STAGE: September 16, 2022
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    Several derivatives of 1,3-dithiole[3]dendralene with one thiophene spacer (1) were newly prepared. X-ray structure analysis of the hexamethyl-1 (1Aa) revealed that 1Aa adopts a structure with significant distortion between the central 1,3-dithiole (DT) ring and the thiophene ring. Cyclic voltammograms of all the derivatives were composed of three pairs of one-electron redox waves in correspondence with the presence of three redox-active DT rings. The results of cyclic voltammetry and spectroelectrochemistry indicated that a positive charge in 1Aa•+ is mainly delocalized on the vinyl-extended tetrathiafulvalene (TTF) moiety, while two positive charges in 1Aa2+ are mainly distributed on the thiophene-inserted TTF moiety. X-ray structure analysis revealed that two-electron oxidation of 1Aa with (4-BrC6H4)3N•+SbCl6 gradually facilitated the formation of a dicationic species of its chlorinated product.

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