Photoluminescence of Lanthanide-Titanium-Oxo Clusters and Based on a β-Diketone Ligand.

A series of acetylacetone-protected lanthanide-titanium-oxo clusters (LTOCs), formulated as [LaTi(μ-OH)(acac)(CHO)(CHOH)] (; Hacac = acetylacetone) and [LnTi(μ-O)(μ-OH)(acac)(CHO)(CHOH)] [Ln = Eu () and Tb ()], were synthesized through the reactions of LnCl·6HO (Ln = La, Eu, and Tb), Hacac, Ti(OPr), and triethylamine in methanol. Crystal structural analysis shows that exhibits an hourglass-like structure consisting of two LaTi cubane subunits by sharing one Ti ion, while can be viewed as a combination of four EuTi cubane subunits by sharing three corners and one side. The photoluminescence (PL) measurements show that exhibits excellent PL properties with a high quantum yield (QY) of 34.8%, while only has a QY of 1.4% because of the different photosensitizations of ligands to Eu and Tb ions in the photophysical process.