Syntheses, structure and near-infrared (NIR) luminescence of Er2, Yb2, ErYb of homodinuclear and heterodinuclear lanthanide(iii) complexes based on salen ligand

Abstract

Three dinuclear lanthanide complexes are achieved by using H2salen or H2salen/acac ligands (H2salen = N,N′-ethylenebis(salicylideneimine), acac = acetylacetonate). They are homodinuclear [Er2(salen)3] (1), [Yb2(salen)2(acac)2] (2), and heterodinuclear geometrical [ErYb(salen)2(acac)2] (3). The structures of complexes were determined by single crystal X-ray crystallographic studies and their photophysical properties were investigated. The homonuclear Yb2 complex exhibits characteristic metal-centered NIR emission. The geometric ErYb isomer exhibits ‘dual emissions’ from both erbium(III) and ytterbium(III) ions. There was no detectable photoluminescence in the Er2 complex, not only in solid state but also in solvent.