Multifunctional Ln-MOF Luminescent Probe for Efficient Sensing of Fe 3+ , Ce 3+ , and Acetone.

A new series of five three-dimensional Ln(III) metal-organic frameworks (MOFs) formulated as [Ln4 (μ6 -L)2 (μ-HCOO)(μ3 -OH)3 (μ3 -O)(DMF)2 (H2 O)4 ] n {Ln3+ = Tb3+ (1), Eu3+ (2), Gd3+ (3), Dy3+ (4), and Er3+ (5)} was successfully obtained via a solvothermal reaction between the corresponding lanthanide(III) nitrates and 2-(6-carboxypyridin-3-yl)terephthalic acid (H3 L). All of the obtained compounds were fully characterized, and their structures were established by single-crystal X-ray diffraction. All products are isostructural and possess porous 3D networks of the fluorite topological type, which are driven by the cubane-like [Ln4 (μ3 -OH)3 (μ3 -O)(μ-HCOO)]6+ blocks and μ6 -L3- spacers. Luminescent and sensing properties of 1-5 were investigated in detail, revealing a unique capability of Tb-MOF (1) for sensing acetone and metal(III) cations (Fe3+ or Ce3+ ) with high efficiency and selectivity. Apart from a facile recyclability after sensing experiments, the obtained Tb-MOF material features a remarkable stability in a diversity of environments such as common solvents, aqueous solutions of metal ions, and solutions with a broad pH range from 4 to 11. In addition, compound 1 represents a very rare example of the versatile Ln-MOF probe capable of sensing Ce3+ or Fe3+ cations or acetone molecules.