Synthesis of (bis)Silicon Complexes of [38], [37], and [36]Octaphyrins: Aromaticity Switch and Stable Radical Cation

Shin Ichiro Ishida, Jinseok Kim, Daiki Shimizu, Dongho Kim, Atsuhiro Osuka

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8 Citations (Scopus)


Silicon complexation of a [38]octaphyrin (1) was accomplished by reaction with an excess amount of MeSiCl3 in the presence of N,N-diisopropylethylamine, thus giving an aromatic [38]octaphyrin bis(silicon) complex 2. This complex was interconvertible with an antiaromatic [36]octaphyrin congener (3) by oxidation with MnO2 and reduction with NaBH4. Curiously, mild oxidation of 2 with ferrocenium hexafluorophosphate afforded a [37]octaphyrin bis(silicon) complex 4 as an stable radical cation that can be stored under ambient conditions in the solid state. Owing to the two NNNCC-five-coordinated Si atoms bearing trigonal bipyramidal geometry, these octaphyrin bis(silicon) complexes take on similar and rigid figure-of-eight structures with different consecutive numbers of conjugated π-electrons (38, 37, and 36), and are all stable.

Original languageEnglish
Pages (from-to)5876-5880
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number20
Publication statusPublished - 2018 May 14

Bibliographical note

Funding Information:
The work at Kyoto was supported by JSPS KAKENHI Grant Numbers (Nos.: 25220802 (Scientific Research (S)), 16K13952 (Exploratory Research). The work at Yonsei was supported by the Global Research Laboratory (GRL) Program funded by the Ministry of Science, ICT & Future, Korea (2013K1A1A2A02050183). The authors thank Prof. Dr. N. Aratani at the Nara Institute of Science and Technology (NAIST) for X-ray diffraction analysis and Prof. Dr. T. Ikeue and Mr. Y. Ide at Shimane University for ESR measurement. S.I. and D.S. acknowledge JSPS Fellowship for Young Scientists.

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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