Chemistry Letters
Online ISSN : 1348-0715
Print ISSN : 0366-7022
ISSN-L : 0366-7022
Volume 49, Issue 5
Displaying 1-32 of 32 articles from this issue
Letter
Highlight Review
  • Keishiro Tahara, Masaaki Abe
    2020 Volume 49 Issue 5 Pages 485-492
    Published: May 05, 2020
    Released on J-STAGE: May 05, 2020
    JOURNAL RESTRICTED ACCESS

    Mixed valency is a well-known phenomenon in which charge distributions can change via intervalence charge transfer. In addition, there are many other ubiquitous phenomena for charges such as proton transfer, zwitterionization, charge separation, and some supramolecular interactions. However, a basic understanding of the interface between mixed valency and other charge-involved phenomena remains poor. Recent progress is described in creating mixed-valence subspecies by introducing stimuli-responsiveness to conventional mixed-valence frameworks and interplay between mobile charges and charges introduced via light and ions.

    Mixed valency is a well-known phenomenon in which charge distributions change via intervalence charge transfer. A basic understanding of the interface between mixed valency and other charge-involved phenomena remains poor. This Highlight Review describes new mixed-valence subspecies with stimuli-responsiveness and interplay between mobile charges and charges newly introduced by light and ions. Fullsize Image
     
Letter
Highlight Review
  • Yuta Kondo, Hiroyuki Morimoto, Takashi Ohshima
    2020 Volume 49 Issue 5 Pages 497-504
    Published: May 05, 2020
    Released on J-STAGE: May 05, 2020
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    Benzophenone imine and its derivatives are useful ammonia equivalents for synthesizing primary amines, readily achieving the selective formation of primary amines and obtaining easily deprotectable imines as the product. These advantages have led to the development of various C–N bond-forming reactions in recent years. In this Highlight Review, we summarize the progress related to their reaction patterns.

    Benzophenone imine and its derivatives are useful ammonia equivalents for synthesizing primary amines, readily achieving the selective formation of primary amines and obtaining easily deprotectable imines as the product. These advantages have led to the development of various C-N bond-forming reactions in recent years. In this Highlight Review, we summarize the progress related to their reaction patterns. Fullsize Image
     
Letter
Editor's Choice
  • Kenichi Kato, Atsuhiro Osuka
    2020 Volume 49 Issue 5 Pages 517-520
    Published: May 05, 2020
    Released on J-STAGE: May 05, 2020
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    NiII-2,18-dibromo-20-chloroporphyrin was fused with N1,N3,N5-triaryl-1,3,5-benzenetriamine via t-BuONa-promoted one-pot reaction to give a helically twisted nitrogen-doped fused porphyrin dimer with high selectivity instead of a trimeric porphyrin. The dimer shows a red-shifted and broad electronic absorption spectrum and negatively shifted multi-stage oxidation behavior owing to the significant electronic effect of the embedded amine-type nitrogen atoms and inter-porphyrinic interaction. Bis-NiII-dimer was successfully converted to the corresponding bis-ZnII-complex, which exhibits fluorescence at around 650–700 nm.

Letter
Editor's Choice
Letter
Highlight Review
  • Yosuke Sumiya, Satoshi Maeda
    2020 Volume 49 Issue 5 Pages 553-564
    Published: May 05, 2020
    Released on J-STAGE: May 05, 2020
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    This paper reviews the rate constant matrix contraction (RCMC) method, a kinetics-based graph clustering approach developed for the network of paths of chemical reaction elementary steps. First, fundamentals of the transition state theory and the concept and algorithm of the RCMC method are introduced. Next, the RCMC method is explained for kinetic simulation and kinetics-based navigation of automated reaction path search. The RCMC-based kinetic simulation enables quick evaluation of population of chemical species involved at a specific time without explicit time-evolution of the rate equations. The kinetics-based navigation combined with the single component artificial force induced reaction (SC-AFIR) method dramatically reduces the cost of SC-AFIR searches by restricting the search areas to those that are kinetically accessible from the initial structure under a given reaction temperature and timescale. These approaches are presented together with some example applications.

    This paper reviews the rate constant matrix contraction (RCMC) method, a kinetic method developed for the network of paths of chemical reaction elementary steps. RCMC enables quick evaluation of population of chemical species involved at a specific time without explicit time-evolution of the rate equations. RCMC is also utilized in the kinetics-based navigation which dramatically accelerates the automated reaction path search. Its theoretical backgrounds and application examples to various chemical reactions are presented. Fullsize Image
     
  • Masashi Kunitake, Shinobu Uemura
    2020 Volume 49 Issue 5 Pages 565-573
    Published: May 05, 2020
    Released on J-STAGE: May 05, 2020
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    Several fabrication technologies for molecular level ultra-thin films, from organic to organic–inorganic hybrids, are introduced using the surface imaging technology of scanning probe microscopy (SPM). Electrochemical scanning tunneling microscopy (EC-STM), atomic force microscopy (AFM) and related techniques enable the observation of the surface of 2D materials in near real-time and in real-space. The combination of 2D materials and SPM technology opens up a new avenue of surface and material science, despite its many restrictions.

    Several fabrication technologies for molecular level ultra-thin films, from organic to organic-inorganic hybrids, are introduced using the surface imaging technology of scanning probe microscopy (SPM). Electrochemical scanning tunneling microscopy (EC-STM), atomic force microscopy (AFM) and the related techniques enable the observation of the surface of 2D materials in near real-time and in real-space. The combination of 2D materials and SPM technology opens up a new avenue of surface and material science, despite its many restrictions. Fullsize Image
     
  • Takeharu Haino, Takehiro Hirao
    2020 Volume 49 Issue 5 Pages 574-584
    Published: May 05, 2020
    Released on J-STAGE: May 05, 2020
    JOURNAL RESTRICTED ACCESS

    Head-to-tail dipole-dipole arrays of isoxazole rings lead to supramolecular helical assemblies where the assembly and disassembly are regulable based on temperature and solvent properties. The cooperative supramolecular polymerization characterized by a two-step polymerization consisting of nucleation and elongation is driven by the multiple dipole array as well as the induced dipoles in the supramolecular organization. The helical supramolecular assemblies are fabricated with the aid of multiple dipole–dipole interactions. The chiroptical properties, such as CD and CPL, are determined by the right-handed and left-handed helicities of the supramolecular organizations, which are directed by the stereogenic side chains. The AIE and AIEE are established in the supramolecular assemblies. The AIE feature of the platinum complex is inherent in the supramolecular assemblies, which results in luminogenic micelles. Emissive supramolecular micelles are fabricated. In this review, these aspects are briefly described, emphasizing the importance of the intermolecular dipole-dipole interactions in supramolecular chemistry.

    Head-to-tail dipole-dipole arrays of isoxazole rings lead to supramolecular helical assemblies. The cooperative supramolecular polymerization characterized by a two-step polymerization consisting of nucleation and elongation is driven by the multiple dipole array as well as the induced dipoles in the supramolecular organization. The helical supramolecular assemblies are fabricated with the aid of multiple dipole-dipole interactions. The chiroptical properties, such as CD and CPL, are determined by the right-handed and left-handed helicities of the supramolecular organizations. The AIE and AIEE features of the platinum complex are inherent in the supramolecular assemblies, which results in luminogenic micelles. In this review, these aspects are briefly described, emphasizing the importance of the intermolecular dipole-dipole interactions in supramolecular chemistry. Fullsize Image
     
Letter
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