Isotopically enriched polymorphs of dysprosium single molecule magnets

A triclinic polymorph Dy(t) and a monoclinic polymorph Dy(m) of [Dy(tta)(3)(L)] with L = 4-[6-(1,3-benzothiazol-2-yl) pyridin-3-yl]-4',5'-bis(methylthio) tetrathiafulvene behave as Single-Molecule Magnets with hysteresis loops opened at zero field. Magnetic properties were enhanced through magnetic dilution and Dy-164 isotopic enrichment which definitively support the importance of isotopes for the control of quantum magnets.