Stable hydrocarbon diradical, an analogue of trimethylenemethane

Andrzej Rajca, Kouichi Shiraishi, Matthew Vale, Hongxian Han, Suchada Rajca

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43 Scopus citations


Hydrocarbon diradical 1, a new stable, 3-fold symmetric analogue of trimethylenemethane (TMM) with no heteroatom perturbation, is prepared and studied. Such diradicals should provide new building blocks for high-spin hydrocarbon polyradicals with very strong net ferromagnetic coupling. Magnetic studies (SQUID) and EPR spectroscopy indicate that 1 in tetrahydrofuran-d 8 (THF-d8) possesses a triplet (S = 1) ground state, with strong ferromagnetic coupling. After annealing at room temperature, the EPR spectra of 1 (∼0.02 M in frozen THF-d8) consist of a single narrow resonance (ΔHpp < 1 G), and intermolecular antiferromagnetic coupling is increased by 1 order of magnitude. This behavior is consistent with the presence of exchange narrowing, thus suggesting aggregation of 1 in THF-d8. Blue solutions of 1 in THF-d8 possess a strong UV-vis absorption band at λmax ≈ 640 nm. Diradical 1 in THF-d8 is stable (or persistent) at room temperature, with no detectable decomposition for at least 2 days.

Original languageEnglish (US)
Pages (from-to)9014-9020
Number of pages7
JournalJournal of the American Chemical Society
Issue number25
StatePublished - Jun 29 2005

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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