S = 1 Tetraazacyclophane Diradical Dication with Robust Stability: A Case of Low-Temperature One-Dimensional Antiferromagnetic Chain

Wenqing Wang, Chao Chen, Chan Shu, Suchada Rajca, Xinping Wang, Andrzej Rajca

Research output: Contribution to journalArticle

8 Scopus citations


One-dimensional (1D) spin-1 (S = 1) chain of organic radicals with low local magnetic anisotropy may provide a better understanding of the low-dimensional magnetism. We report solid-state studies, including single crystal X-ray crystallography, of air-stable tetraazacyclophane diradical dication salt 1 2·2+ ·2[Al(OC(CF 3 ) 2 CH 3 ) 4 ] - with a triplet ground state (ΔE ST ≈ 0.5 kcal mol -1 ). The magnetic behavior for 1 2·2+ at low temperature is best modeled by 1D spin S = 1 Heisenberg chain with intrachain antiferromagnetic coupling of J′/k = -5.4 K, which is associated with the interaryl C···C contacts, including π-π interactions. Zero-field splitting value, |D/hc| ≈ 5.6 × 10 -3 cm -1 , for 1 2·2+ is rather small; thus, the 1D chains are characterized by the high degree of isotropicity |D/2J′| ≈ 7.5 × 10 -4 . The diradical dication salt possesses extraordinary stability with onset of decomposition at temperature of about 180 °C (∼450 K), based on thermogravimetric analysis and EPR spectroscopy.

Original languageEnglish (US)
Pages (from-to)7820-7826
Number of pages7
JournalJournal of the American Chemical Society
Issue number25
StatePublished - Jun 27 2018


ASJC Scopus subject areas

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

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