Chemistry Letters
Online ISSN : 1348-0715
Print ISSN : 0366-7022
ISSN-L : 0366-7022
最新号
選択された号の論文の33件中1~33を表示しています
Letter
Vol. 50 Commemorative Highlight Review
  • Jenna K. Buchanan, Paul G. Plieger
    2021 年 50 巻 2 号 p. 227-234
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Ligands which incorporate second-sphere intramolecular hydrogen bonding show potential for enhancing selectivity and binding strength for beryllium. In this highlight review, recent advances in the design of tetradentate ligands to selectively bind beryllium are discussed, as is the use of electrospray ionization mass spectrometry (ESI-MS) and 9Be nuclear magnetic resonance (NMR) spectroscopy as tools for the analysis of beryllium coordination compounds.

    Ligands which incorporate second-sphere intramolecular hydrogen bonding show potential for enhancing selectivity and binding strength for beryllium. In this highlight review, recent advances in the design of tetradentate ligands to selectively bind beryllium are discussed, as is the use of electrospray ionization mass spectrometry (ESI-MS) and 9Be nuclear magnetic resonance (NMR) spectroscopy as tools for the analysis of beryllium coordination compounds. Fullsize Image
     
Letter
Vol. 50 Commemorative Highlight Review
  • Kazuo Tanaka, Yoshiki Chujo
    2021 年 50 巻 2 号 p. 269-279
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    In this manuscript, we will illustrate a new idea for narrowing energy gaps between frontier molecular orbitals (FMOs) by selectively perturbing the levels of highest occupied molecular orbitals (HOMOs) and/or lowest unoccupied molecular orbitals (LUMOs). Initially, the basic concept of the isolated FMOs is explained by employing pentaazaphenalene (5AP) derivatives. It was found that electronic structures of the isolated LUMO of 5AP can be preserved even when incorporated into polymer chains if the connecting points are separated from the isolated LUMO. The mechanism and their unique electronic properties are summarized. Next, conversely, isolated HOMO and LUMO can be perturbed by conjugation effects independently. On the basis of this fact, near infrared (NIR)-absorbing molecules can be obtained by selectively elevating HOMO and lowering LUMO energy levels. We also mention strategies for enhancing luminescent properties of 5AP derivatives. Finally, we demonstrate that the isolated LUMO can be found in commodity luminescent dyes, such as boron dipyrromethene (BODIPY). By selectively lowering the LUMO energy level through the aza-substitution at the skeletal carbon where the isolated LUMO is distributed, NIR-emissive polymers can be obtained. Versatility of the isolated FMOs for obtaining optoelectronic organic materials is explained in this review.

    Near-infrared (NIR)-absorbing and emissive materials have attracted attention as a platform for constructing advanced optoelectronic materials. In this review, we will illustrate the new idea for narrowing energy gaps between frontier molecular orbitals (FMOs), which are essential electronic structures for constructing NIR materials, by selectively perturbing the levels of one of FMOs. Fullsize Image
     
Vol. 50 Commemorative Highlight Review
Award Highlight Review
  • Takehiko Tosha, Raika Yamagiwa, Hitomi Sawai, Yoshitsugu Shiro
    2021 年 50 巻 2 号 p. 280-288
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Nitric oxide (NO) is generated in some biological systems. Due to its radical character, it exhibits high reactivity, but biological system can manage NO without sustaining any damage to bio-compounds in the cell. As a model system to understand how the NO dynamics is controlled in the cell, we have been studying denitrification of microbial respiration, in which NO is generated as an intermediate product. In denitrification, it was found that NO produced by the NO-generating enzyme (NiR: nitrite reductase) can be smoothly transferred to the NO-decomposing enzyme (NOR: nitric oxide reductase) by making a complex of the two enzymes. The chemical mechanism of the NO decomposition by NOR was also revealed by the time-resolved spectroscopic techniques.

    Biological systems can manage cytotoxic NO without giving any damage to biocompounds in the cell. As a model system to understand how the NO dynamics is controlled in the cell, we have been studying microbial denitrification, in which NO is generated as an intermediate product. We found that NO produced by the NO-generating enzyme (NiR: nitrite reductase) can be smoothly transferred to the NO-decomposing enzyme (NOR: nitric oxide reductase) by forming a complex. The NO decomposition mechanism by NOR was also revealed by time-resolved spectroscopic techniques. Fullsize Image
     
Letter
Editor's Choice
Vol. 50 Commemorative Highlight Review
  • Yasuyuki Yokota, Yousoo Kim
    2021 年 50 巻 2 号 p. 297-304
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Microscopic studies on electrolyte solution/electrode interfaces provide the most fundamental information not only for understanding the electric double layer formed at the interfaces but also for designing sophisticated electrochemical devices. Various types of in situ techniques, performed without taking the electrode out of electrolyte solutions, have become indispensable tools. Among them, electrochemical tip-enhanced Raman spectroscopy (EC-TERS) is considered as an ultimate tool because of simultaneous measurements of electrochemical scanning tunneling microscopy (EC-STM) and Raman spectroscopy just underneath the EC-STM tip. On the other hand, ex situ techniques, where the electrode is emersed from the solution to perform precise measurements, have been still useful because the detailed information not easy to obtain by in situ techniques is available just by combining conventional instruments, such as photoelectron spectroscopy (PES) for the analysis of electronic states. In this highlight review, we present our recent progresses with in situ (EC-TERS) and ex situ (PES combined with electrochemistry) experiments for elucidating the microscopic properties of electric double layers. Current issues and future perspective of both techniques are also discussed in detail.

    Combining electrochemical scanning tunneling microscopy (EC-STM) and tip-enhanced Raman spectroscopy (TERS) makes it possible to obtain information on the chemical species directly under the STM tip (EC-TERS). If the electrode is pulled up from the solution with keeping the electrochemical interfaces, precise and detailed measurements in vacuum such as photoelectron spectroscopy (PES) become available. Fullsize Image
     
  • Yuya Oaki
    2021 年 50 巻 2 号 p. 305-315
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Exfoliation of layered materials provides nanosheets, such as monolayers and few-layers. In recent years, nanosheets have attracted much interest as two-dimensional (2D) materials for their diverse properties and applications originating from the anisotropic characteristic structures. Exfoliation methods have been developed depending on the types of interactions between the layers, such as van der Waals and electrostatic interactions. The present review focuses on exfoliation chemistry based on rigid and soft natures of the layered materials. The rigid inorganic layered compounds are converted to the soft layered materials with interaction of organic guests. The surface-functionalized nanosheets are obtained by exfoliation of the soft layered composites with dispersion in organic media. The exfoliation behavior is governed by the flexibility of the precursor layered materials, i.e. interaction between the interlayer guest and dispersion medium. Although exfoliation is generally an uncontrollable top-down process, materials informatics on our own experimental small data assists elucidation of the control factors toward tailored 2D materials. The exfoliation schemes are applied to a variety of layered materials. The present review shows potential new insights for exfoliation chemistry of soft layered materials.

    Exfoliation of layered materials provides nanosheets, such as monolayers and few-layers. The present review focuses on new exfoliation chemistry based on soft layered materials and materials informatics. Although exfoliation is generally an uncontrollable top-down process, the present approach has potentials for control of the exfoliation behavior. Fullsize Image
     
Letter
Vol. 50 Commemorative Highlight Review
  • Naoki Ousaka, Eiji Yashima
    2021 年 50 巻 2 号 p. 320-330
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    A wide variety of synthetic molecular machines has been designed and synthesized to construct nanometer-scale assemblies whose molecular motions can be precisely controlled by external stimuli. A helical structure is one of the most intriguing structural motifs to realize such molecular machines, because of its unique spring-like shape that enables reversible extension and contraction motions. This short review highlights the recent progress in the synthesis, structures, and functions of synthetic molecular springs based on single- and multi-stranded helical structures.

    This review highlights the recent progress in synthesis, structures, and functions of stimuli-responsive synthetic molecular springs based on single- and multi-stranded helical structures. Fullsize Image
     
  • Yoshiaki Furukawa
    2021 年 50 巻 2 号 p. 331-341
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Cu/Zn-superoxide dismutase (SOD1) is a metalloenzyme that catalyzes the disproportionation of superoxide. This review summarizes intracellular processes for metal binding and disulfide formation in SOD1, both of which are essential to stabilization of the protein structure as well as its enzymatic function. Also, failure of those processes as a possible cause of a neurodegenerative disease through protein misfolding will be described.

    Cu/Zn-superoxide dismutase (SOD1) is a metalloenzyme that catalyzes the disproportionation of superoxide. This review summarizes intracellular processes for metal binding and disulfide formation in SOD1, both of which are essential to stabilization of the protein structure as well as its enzymatic function. Also, failure of those processes as a possible cause of a neurodegenerative disease through protein misfolding will be described. Fullsize Image
     
Letter
Highlight Review
  • Hiroki Miura, Tetsuya Shishido
    2021 年 50 巻 2 号 p. 346-352
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    The PdAu random alloy nanoparticle catalyst shows excellent catalytic activity for heterogeneous molecular formations, whereas monometallic Pd or Au catalysts were ineffective. The Pd/Au ratio in the alloy had a significant impact on its catalytic performance, and the catalyst with a low Pd concentration exhibited excellent activity. The concerted catalysis of Pd and Au adjacent on the alloy surface is responsible for the specific catalytic performance.

    The PdAu alloy nanoparticle catalyst shows excellent catalytic activity for heterogeneous molecular formations, whereas monometallic Pd or Au catalysts were ineffective. The Pd/Au ratio in the alloy had a significant impact on its catalytic performance, and the catalyst with a low Pd concentration exhibited excellent activity. The concerted catalysis of Pd and Au adjacent on the alloy surface is responsible for the specific catalytic performance. Fullsize Image
     
  • Tomohiro Watanabe, Seigo Shima
    2021 年 50 巻 2 号 p. 353-360
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Ferredoxin is a type of electron carrier protein involved in many biological redox reactions and also incorporated as an electron transfer domain and subunit in redox enzyme complexes. MvhB-type polyferredoxin is an iron-sulphur protein composed of three to seven 2[4Fe-4S]-ferredoxin domains. In this short review, we introduce the structure and function of MvhB-type polyferredoxin modules in methanogenic enzymes and then discuss the possible physiological function of the putative MvhB-like polyferredoxins identified in microbial genomes.

    MvhB-type polyferredoxin is an iron-sulphur protein composed of three to seven 2[4Fe-4S]-ferredoxin domains. In this short review, we introduce the structure and function of MvhB-type polyferredoxin in methanogenic archaea and then discuss the possible physiological function of the putative MvhB-like polyferredoxins identified in microbial genomes. Fullsize Image
     
Vol. 50 Commemorative Highlight Review
  • Satoshi Nakamura, Hideyuki Mitomo, Kuniharu Ijiro
    2021 年 50 巻 2 号 p. 361-370
    発行日: 2021/02/05
    公開日: 2021/02/15
    ジャーナル 認証あり

    Inorganic nanoparticles are an attractive material that shows unique properties that differ from their bulk counterparts. Assembly of nanoparticles with soft materials is an effective approach to leverage their unusual properties for the fabrication of functional devices. Among the various soft materials, polymer brushes are expected to offer exciting opportunities due to their unique conformational properties. Here, we review research progress in the assembly and active control of gold nanoparticles with polymer brushes as a scaffold.

    Inorganic nanoparticles are an attractive material that shows unique properties that differ from their bulk counterparts. Assembly of nanoparticles with soft materials, in particular polymer brushes, is an effective approach to leverage their unusual properties for the fabrication of functional devices. In this highlight review, research progress in the assembly and active control of gold nanoparticles with polymer brushes as a soft scaffold is introduced. Fullsize Image
     
Letter
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