Molecules (Jun 2020)

Synthesis of Nitroxide Diradical Using a New Approach

  • Pavel Fedyushin,
  • Tatyana Rybalova,
  • Nargiz Asanbaeva,
  • Elena Bagryanskaya,
  • Alexey Dmitriev,
  • Nina Gritsan,
  • Maxim Kazantsev,
  • Evgeny Tretyakov

DOI
https://doi.org/10.3390/molecules25112701
Journal volume & issue
Vol. 25, no. 11
p. 2701

Abstract

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A new synthetic pathway to diradical organic systems is proposed. The effectiveness of this approach was exemplified by the synthesis of a new nitroxide diradical. An interaction of perfluorobiphenyl with lithium tert-butylamide, followed by oxidation of the thusly formed N4,N4′-di-tert-butyl-2,2′,3,3′,5,5′,6,6′-octafluorobiphenyl-4,4′-diamine with meta-chloroperoxybenzoic acid, led to the polyfluorinated nitroxide diradical, N,N′-(perfluorobiphenyl-4,4′-diyl)bis(N-tert-butyl(oxyl)amine), with a good total yield. The polyfluorinated diradical is stable and can be isolated in free form and completely characterized. The structure of the nitroxide diradical was proved by single-crystal X-ray diffraction analysis. According to the X-ray diffraction data, the diradical is considerably twisted: dihedral angles between the planes of the nitroxide groups and aromatic cycles are 65.1° and 69.5°, and between aromatic cycles 52.6°. Quantum chemical calculations predict well-balanced size of both intramolecular and intermolecular exchange interactions with J from −2.65 to −1.14 cm−1.

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