Reversible Pressure-Magnetic Modulation in a Tetrathiafulva-lene-Based Dyad Piezochromic Dysprosium Single-Molecule Magnet

The extreme sensitivity of trivalent lanthanide ions to crystal field variations led to the emergence of single-molecule mag-netic switching under various stimuli. The use of pressure as an external stimulus instead of classic light irradiation, oxidation or any chemical reactions allows a fine tuning of the magnetic modulation. Here the well-known pure isotopically enriched [162Dy(tta)3(L)]C6H14 (162Dy) Single-Molecule Magnet (SMM) (tta- = 2-2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)-tetrathiafulvalene-2-(2-pyridyl)benzimidazole-methyl-2-pyridine) was experimentally investigated by single-crystal diffraction and squid magnetometry under high applied pressures. Both reversible piezochromic properties and pres-sure modulation of the SMM behavior were demonstrated and supported by ab initio calculations. The magnetic study of the diluted sample [162Dy0.05Y0.95(tta)3(L)]C6H14 (162Dy@Y) indicated that variations in the electronic structure have both intra- and inter-molecular origins. Quantitative magnetic interpretation concludes to a deterioration of the Orbach process for the benefit of both Raman and QTM mechanisms under applied pressure.