Tetrathiafulvalene-Based Helicene Ligand in the Design of a Dysprosium Field-Induced Single-Molecule Magnet.

The design of a coordination complex that involves a ligand combining both a tetrathiafulvalene core and a helicene fragment was achieved thanks to the reaction between the new 2-{1-[2-methyl[6]helicene]-4,5-[4,5-bis(propylthio)tetrathiafulvalenyl]-1 H-benzimidazol-2-yl}pyridine ligand (L) and the Dy(hfac)3·2H2O metalloprecursor. Magnetic investigations showed field-induced single-molecule-magnet (SMM) behavior under an applied magnetic field of 1000 Oe for [Dy(hfac)3(L)]·0.5CH2Cl2, while experimentally oriented single-crystal magnetic measurements allowed for determination of the magnetic anisotropy orientation. The magnetic behavior was rationalized through ab initio CASSCF/SI-SO calculations. This redox-active chiral-field-induced SMM paves the way for the design of switchable-multiproperty SMMs.