Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide

Takuma Tahara, Shuichi Suzuki, Masatoshi Kozaki, Daisuke Shiomi, Kenji Sugisaki, Kazunobu Sato, Takeji Takui, Yota Miyake, Yuko Hosokoshi, Hiroyuki Nojiri, Keiji Okada

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The spin–spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, (DAA-PTZ)+-NN⋅MBr4 (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh3 followed by oxidation with the thianthrenium radical cation (TA+⋅MBr4). These salts were found to be highly stable under aerobic conditions. For the GaBr4 salt, large ferromagnetic intramolecular and small antiferromagnetic intermolecular interactions (J1/kB=+320 K and J2/kB=−2 K, respectively) were observed. The magnetic property of the Fe3+ salt was analyzed by using a six-spin model assuming identical intramolecular exchange interaction (J3/kB=+320 K) and the other exchange interactions (J4/kB=−7 K and J5/kB=−4 K). A significant color change was observed in the UV/Vis/NIR absorption spectra upon electrochemical oxidation of the doublet DAA-PTZ-NN to the triplet (DAA-PTZ)+-NN.

Original languageEnglish
Pages (from-to)7201-7209
Number of pages9
JournalChemistry - A European Journal
Volume25
Issue number29
DOIs
Publication statusPublished - 2019 May 23

Keywords

  • electronic structure
  • magnetic properties
  • radical ions
  • redox chemistry
  • structure elucidation

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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