Slow Magnetic Relaxation in a Redox-Active Tetrathiafulvalene-Based Ferromagnetic Dysprosium Complex

Fabrice Pointillart (1) , Stéphane Golhen (1) , Olivier Cador (1) , Lahcène Ouahab (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

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.

Mots clés: Sulfur heterocycles; Lanthanides; Redox chemistry; Magnetic properties; Single-molecule magnets

Domaines: Chimie

Fabrice Pointillart, Stéphane Golhen, Olivier Cador, Lahcène Ouahab. Slow Magnetic Relaxation in a Redox-Active Tetrathiafulvalene-Based Ferromagnetic Dysprosium Complex. European Journal of Inorganic Chemistry, 2014, 2014 (27), pp.4558-4563. ⟨10.1002/ejic.201402181⟩. ⟨hal-01120071⟩