An azophenine radical-bridged Fe2 single-molecule magnet with record magnetic exchange coupling

Ie Rang Jeon, Jesse G. Park, Dianne J. Xiao, T. David Harris*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

121 Scopus citations


One-electron reduction of the complex [(TPyA)2Fe II2(NPhL2-)]2+ (TPyA = tris(2-pyridylmethyl)amine, NPhLH2 = azophenine = N,N′,N″,Nâ€́-tetraphenyl-2,5-diamino-1, 4-diiminobenzoquinone) affords the complex [(TPyA)2Fe II2(NPhL3-•)]+. X-ray diffraction and Mössbauer spectroscopy confirm that the reduction occurs on NPhL2- to give an S = 1/2 radical bridging ligand. Dc magnetic susceptibility measurements demonstrate the presence of extremely strong direct antiferromagnetic exchange between S = 2 FeII centers and NPhL3-• in the reduced complex, giving an S = 7/2 ground state with an estimated coupling constant magnitude of |J| ≥ 900 cm-1. Mössbauer spectroscopy and ac magnetic susceptibility reveal that this complex behaves as a single-molecule magnet with a spin relaxation barrier of Ueff = 50(1) cm-1. To our knowledge, this complex exhibits by far the strongest magnetic exchange coupling ever to be observed in a single-molecule magnet.

Original languageEnglish (US)
Pages (from-to)16845-16848
Number of pages4
JournalJournal of the American Chemical Society
Issue number45
StatePublished - Nov 13 2013

ASJC Scopus subject areas

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


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