Er Magnetic and Luminescent Compounds
The development of the multifunctionality approach towards lanthanoid-based materials has proven to be a challenge. Based on the search for dual-function (luminescent and magnetic) materials, the studies of several Er3+ complexes have been pursued including the investigation of a new Er3+ homodinuclear complex bridged by an aromatic molecule, [Er2(nd)6(μ-bpm)], in which nd = 2,4-nonanedione and bpm = 2,2′-bipyrimidine. The Lewis base allows indirect exchange between lanthanide magnetic moments, either promoting antiferro- or ferromagnetic interactions. The complex displayed NIR luminescence when excited in the UV region (360-375 nm), after a ligand-to-lanthanide energy transfer and showed slow relaxation of magnetization only when a small DC field was applied. Some persistence of a relaxation by quantum tunnelling via the ground state and the first excited state was explained by the lack of a perfect axial g-tensor, allowing a small mixing between the ground and excited states, as elucidated by the ab-initio calculations.