Formation of Ground State Triplet Diradicals from Annulated Rosarin Derivatives by Triprotonation

Shunichi Fukuzumi, Kei Ohkubo, Masatoshi Ishida, Christian Preihs, Bo Chen, Weston Thatcher Borden, Dongho Kim, Jonathan L. Sessler

研究成果: Contribution to journalArticle査読

19 被引用数 (Scopus)


Annulated rosarins, β,β′-bridged hexaphyrin( derivatives 1-3, are formally 24 π-electron antiaromatic species. At low temperature, rosarins 2 and 3 are readily triprotonated in the presence of trifluoroacetic acid in dichloromethane to produce ground state triplet diradicals, as inferred from electron paramagnetic resonance (EPR) spectral studies. From an analysis of the fine structure in the EPR spectrum of triprotonated rosarin H333+, a distance of 3.6 Å between the two unpaired electrons was estimated. The temperature dependence of the singlet-triplet equilibrium was determined by means of an EPR titration. Support for these experimental findings came from calculations carried out at the (U)B3LYP/6-31G∗ level, which served to predict a very low-lying triplet state for the triprotonated form of a simplified model system 1.

ジャーナルJournal of the American Chemical Society
出版ステータス出版済み - 8 12 2015

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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