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Photoluminescence of Lanthanide-Titanium-Oxo Clusters Eu and Tb Based on a β-Diketone Ligand
Wei-Dong Liu1, Guan-Jun Li1, Han Xu1
1Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Abstract:
A series of acetylacetone-protected lanthanide-titanium-oxo clusters (LTOCs), formulated as [La6Ti(μ3-OH)8(acac)12(CH3O)2(CH3OH)6] (LaTi; Hacac = acetylacetone) and [Ln9Ti2(μ4-O)(μ3-OH)14(acac)17(CH3O)2(CH3OH)3] [Ln = Eu (EuTi) and Tb (TbTi)], were synthesized through the reactions of LnCl3·6H2O (Ln = La, Eu, and Tb), Hacac, Ti(OPr)4, and triethylamine in methanol. Crystal structural analysis shows that LaTi exhibits an hourglass-like structure consisting of two La3Ti cubane subunits by sharing one Ti4+ ion, while EuTi can be viewed as a combination of four Eu3Ti cubane subunits by sharing three corners and one side. The photoluminescence (PL) measurements show that TbTi exhibits excellent PL properties with a high quantum yield (QY) of 34.8%, while EuTi only has a QY of 1.4% because of the different photosensitizations of ligands to Eu3+ and Tb3+ ions in the photophysical process.
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