Spontaneous Formation of an Air-Stable Radical upon the Direct Fusion of Diphenylmethane to a Triarylporphyrin

Kenichi Kato; Wonhee Cha; Juwon Oh; Ko Furukawa; Hideki Yorimitsu; Dongho Kim; Atsuhiro Osuka

doi:10.1002/anie.201602683

Spontaneous Formation of an Air-Stable Radical upon the Direct Fusion of Diphenylmethane to a Triarylporphyrin

Angew Chem Int Ed Engl. 2016 Jul 18;55(30):8711-4. doi: 10.1002/anie.201602683. Epub 2016 Jun 3.

Authors

Kenichi Kato¹, Wonhee Cha², Juwon Oh², Ko Furukawa³, Hideki Yorimitsu⁴, Dongho Kim⁵, Atsuhiro Osuka⁶

Affiliations

¹ Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
² Spectroscopy Laboratory of Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul, 120-749, Korea.
³ Center for Instrumental Analysis, Niigata University, Nishi-ku, Niigata, 950-2181, Japan. kou-f@chem.sc.niigata-u.ac.jp.
⁴ Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan. yori@kuchem.kyoto-u.ac.jp.
⁵ Spectroscopy Laboratory of Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul, 120-749, Korea. dongho@yonsei.ac.kr.
⁶ Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan. osuka@kuchem.kyoto-u.ac.jp.

PMID: 27257973
DOI: 10.1002/anie.201602683

Abstract

The direct fusion of a diphenylmethane segment to a Ni(II) 5,10,15-triarylporphyrin with three linkages furnished an air- and moisture-stable neutral radical through unexpected and spontaneous oxidation. This radical was demetalated by treatment with H2 SO4 and CF3 CO2 H to provide the corresponding free-base radical. These porphyrin radicals are very stable owing to spin delocalization and have been fully characterized through UV/Vis/NIR absorption spectroscopy, X-ray crystallographic analysis, magnetic susceptibility measurements, electrochemical studies, laser-based ultrafast spectroscopic studies, and theoretical calculations. They were chemically oxidized and reduced to the corresponding cation and anion but did not react with hydrogen-atom donors.

Keywords: aromaticity; fused-ring systems; porphyrinoids; radical; redox chemistry.

Publication types

Research Support, Non-U.S. Gov't