A Luminescent and Sublimable DyIII-Based Single-Molecule Magnet

• Published in: Chemistry : a European journal 2012-09, Vol.18 (36), p.11379-11387
• Main Authors: Yi, Xiaohui, Bernot, Kevin, Pointillart, Fabrice, Poneti, Giordano, Calvez, Guillaume, Daiguebonne, Carole, Guillou, Olivier, Sessoli, Roberta
• Format: Article
• Language: English
• Subjects: Chemistry; lanthanides; luminescence; magnetic properties; single-molecule magnets; thermal stability
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201201167

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. Single‐molecule detection: [Ln(hfac)3(PyNO)]2 presents a family of luminescent and sublimable, antiferromagnetically coupled dimers. The DyIII derivative (see figure) shows a remarkable single‐molecule‐magnet behavior (τ0=(5.62±0.4)×10−11 s and Δ=(167±1) K). At low temperature, a quantum tunneling regime governs its relaxation and a butterfly hysteretic behavior is visible at 1.4 K.