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Keywords:

  • Sulfur heterocycles;
  • Lanthanides;
  • Redox chemistry;
  • Magnetic properties;
  • Single-molecule magnets

Abstract

The association of the two 4,5-bis(thiomethyl)-4′-carboxytetrathiafulvalene (HL1) and 4,5-bis(thiomethyl)-4′-(2-pyridyl-N-oxide)carbamoyltetrathiafulvalene (L2) with the metalloprecursor [Dy(tta)3]·2H2O (tta = 2-thenoyltrifluoroacetonate) leads to the formation of the dinuclear complex of formula [Dy(tta)2(L1)(L2)]2·2CH2Cl2. Static magnetic measurements highlight significant ferromagnetic interactions between the DyIII ions, and dynamic magnetic measurements demonstrate single-molecule-magnet behaviour with an energy barrier of 20 cm–1 and a relaxation time of 8.6(9) × 10–6 s. The thermal dependence of the magnetic susceptibility was evaluated by using a crystal field approach (Stevens operators), which confirmed the Ising character of the system. Finally, electrochemistry shows a complex multiredox system with the successive oxidations of the two tetrathiafulvalene (TTF) ligands.