| Institution: | 1. Université Européenne de Bretagne (France), INSA, SCR, UMR 6226, F-35708 RENNES, 20 av.des buttes de Coësmes CS70839, 35708 Rennes Cedex (France);2. Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, 263 Avenue du Général Leclerc, 35042 Rennes Cedex (France);3. Università degli Studi “Guglielmo Marconi”, Via Plinio 144, 00193 Rome (Italy)
University of Florence, “Ugo Schiff” Chemistry Department and INSTM Research Unit, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Florence (Italy);4. University of Florence, “Ugo Schiff” Chemistry Department and INSTM Research Unit, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Florence (Italy) |
| Abstract: | The reaction of Ln(hfac)3] ? 2 H2O 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 (τ0=(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. |
