Mononuclear lanthanide complexes incorporating an anthracene group: structural modification, slow magnetic relaxation and multicomponent fluorescence emissions in Dy compounds

Abstract

Four mononuclear lanthanide complexes, [Ln(hfac)₃(depma)(H₂O)] [Ln(III) = Dy (1), Gd (2)], [Dy(hfac)₃(depma)₂]₂·H₂O (3) and [Gd(hfac)₃(depma)₂]·2H₂O (4), have been obtained (hfac = hexafluoroacetylacetonate, depma = 9-diethylphosphonomethyl anthracene) by using one (for 1 and 2) or two (for 3 and 4) depma molecules to substitute coordination water molecules of Ln(hfac)₃(H₂O)₂. It was found that the number of introduced depma ligands can modify the coordination geometry of Ln(III) ions, showing a distorted biscapped triangular prism geometry in isostructural 1 and 2 and a distorted square-antiprismatic geometry in 3 and 4. Magnetic studies reveal that both 1 and 3 show field-induced slow magnetic relaxation under the applied dc field of 1000 Oe. The solid-state fluorescence measurements indicate the presence of multicomponent emissions in 1 and 3, including ligand-centered (LC) emissions from hfac and depma, and yellow emission from Dy(III) ions and only ligand-centered (LC) emissions in 2 and 4.