Slow Magnetic Relaxation in Lanthanide Complexes with Chelating Nitronyl Nitroxide Radical

Two rare-earth radical complexes [Ln(hfac)<sub>3</sub>NIT-2Py]·0.5C<sub>7</sub>H<sub>16</sub> [Ln = Tb (<b>1</b>), Dy (<b>2</b>)] have been synthesized and characterized structurally as well as magnetically. Both complexes are isomorphous, in which the NIT-2Py radical is coordinated to the Ln<sup>III</sup> ion in a chelating manner. Magnetic studies reveal that complex <b>1</b> shows a frequency-dependent, alternating-current magnetic susceptibility typical of a single-molecule magnet, whereas slow magnetic relaxation is observed in <b>2</b> under an applied direct-current field.