Nuclear Magnetic Shielding and Aromaticity of [18]Annulene and Its Quasi-Möbius-Type Analogues

• Hirotaka Tanimura

  Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University

• Yasushi Honda

  Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University

• Ken-ichi Sugiura

  Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University

• Masahiko Hada

  Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University

抄録

We presented a series of quantum-chemical calculations of [18]annulene (C18H18) and its analogues which are helically distorted open-chain molecules and which we call “quasi-Möbius-type” molecules in this paper. We discussed the proton magnetic shielding constants, the chemical shifts, and the nucleus-independent chemical shift (NICS) of these molecules. The calculated nuclear magnetic shielding constants were decomposed into the diamagnetic and paramagnetic terms using a conventional manner. As we expected, a shielding–deshielding reversal occurs in C18H18 and quasi-Möbius-type C18H20. Moreover, we showed a predictive demonstration that the magnetic shielding constants can be controlled by inserting a small molecule such as CH3− or H2C=CH2 into the terminal π-orbitals of quasi-Möbius-type C18H20 or C16H18. Aromaticity and antiaromaticity are discussed with magnetic features of molecules.

収録刊行物

• Bulletin of the Chemical Society of Japan

  Bulletin of the Chemical Society of Japan 84 (8), 845-854, 2011-07-30

  Oxford University Press (OUP)

キーワード

• General Chemistry

詳細情報

• CRID: 1360846644026929664
• NII論文ID: 130004152955
• DOI: 10.1246/bcsj.20100257
• ISSN: 13480634
• ISSN: 00092673
• Web Site: https://academic.oup.com/bcsj/article-pdf/84/8/845/56272750/bcsj.20100257.pdf
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