AUTHOR=Lefeuvre Bertrand , Galangau Olivier , Gonzalez Jessica Flores , Montigaud Vincent , Dorcet Vincent , Ouahab Lahcène , Le Guennic Boris , Cador Olivier , Pointillart Fabrice 

TITLE=Field-Induced Dysprosium Single-Molecule Magnet Based on a Redox-Active Fused 1,10-Phenanthroline-Tetrathiafulvalene-1,10-Phenanthroline Bridging Triad

JOURNAL=Frontiers in Chemistry

VOLUME=6

YEAR=2018

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2018.00552

DOI=10.3389/fchem.2018.00552

ISSN=2296-2646

ABSTRACT=<p>Tetrathiafulvalene and 1,10-phenanthroline moieties present, respectively remarkable redox-active and complexation activities. In this work, we investigated the coordination reaction between the bis(1,10-phenanthro[5,6-b])tetrathiafulvalene triad (<bold>L</bold>) and the Dy(hfac)<sub>3</sub>·2H<sub>2</sub>O metallo precursor. The resulting {[Dy<sub>2</sub>(hfac)<sub>6</sub>(<bold>L</bold>)]·CH<sub>2</sub>Cl<sub>2</sub>·C<sub>6</sub>H<sub>14</sub>}<sub>3</sub> (<bold>1</bold>) dinuclear complex showed a crystal structure in which the triad <bold>L</bold> bridged two terminal Dy(hfac)<sub>3</sub> units and the supramolecular co-planar arrangement of the triads is driven by donor-acceptor interactions. The frequency dependence of the out-of-phase component of the magnetic susceptibility highlights three distinct maxima under a 2000 Oe static applied magnetic field, a sign that <bold>1</bold> displays a Single-Molecule Magnet (SMM) behavior with multiple magnetic relaxations. <italic>Ab initio</italic> calculations rationalized the Ising character of the magnetic anisotropy of the Dy<sup>III</sup> ions and showed that the main anisotropy axes are perpendicular to the co-planar arrangement of the triads. Single-crystal rotating magnetometry confirms the orientation of the main magnetic axis. Finally combining structural analysis and probability of magnetic relaxation pathways through Quantum Tunneling of the Magnetization (QTM) vs. excited states (Orbach), each Dy<sup>III</sup> center has been attributed to one of the three observed magnetic relaxation times. Such coordination compound can be considered as an ideal candidate to perform redox-magnetic switching.</p>