A luminescent and sublimable Dy(III)-based single-molecule magnet.

The reaction of [Ln(hfac)(3)]·2H(2)O and pyridine-N-oxide (PyNO) leads to isostructural dimers of the formula [Ln(hfac)(3)(PyNO)](2) (Ln=Eu, Gd, Tb, Dy). The Dy derivative shows a remarkable single-molecule magnet behavior with complex hysteresis at 1.4 K. The dynamics of the magnetization features are two relaxation regimes: a thermally activated one at high temperature (τ(0)=(5.62±0.4)×10(-11) s and Δ=(167±1) K) and a quantum tunneling regime at low temperature with a tunneling frequency of 0.42 Hz. The analysis of the Gd derivative evidences intradimer antiferromagnetic interactions (J=(-0.034±0.001) cm(-1)). Moreover, the Eu, Tb, and Dy derivatives are luminescent with quantum yield of 51, 53, and 0.1%, respectively. The thermal investigation of [Dy(hfac)(3)(PyNO)](2) shows that the dimers can be sublimated intact, suggesting their possible exploit as active materials for surface-confined nanostructures to be investigated by fluorimetry methods.