Magnetic properties of conjugated phenoxy polyradicals

Hiroyuki Nishide, Naoki Yoshioka, Eishun Tsuchida

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Formation and magnetic properties of π-conjugated phenoxy radicals bearing a porphyrin macrocycle or a polyacetylenic backbone are described. Tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphinatometals (7-M) [M = Zn(II), VO(II), and Cu(II)] were oxidized to give the corresponding stable monoradical and biradical. Magnetic properties of the radical species depend on the magnetic orbital of the central metal ion. ESR hfs structure reveals that the biradical for 7-Zn and - VO are in the triplet (S = 1) and quartet state (S = 3/2), respectively. Poly(3,5-di-t-butyl-4-hydroxyphenylacetylene) (8) and poly(p-ethynylphenylhydrogalvinoxyl) (9) with molecular weights of ~104 are characterized. ESR spectra with hyperfine structure for 8 indicate that the phenoxy radicals are conjugated with the polyacetylenic main chain over ~7 monomer units as a “neutral soliton.” Formed polyradicals for 8 and 9 are surprisingly stable, even in the solid state, due to resonance stabilization and/or steric effect of the conjugated main chain. An antiferromagnetic interaction is observed for oxidized 8 with a spin concentration above 10 mol%.

Original languageEnglish
Pages (from-to)1261-1273
Number of pages13
JournalJournal of Macromolecular Science: Part A - Chemistry
Volume27
Issue number9-11
DOIs
Publication statusPublished - 1990 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)

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