A Robust Luminescent Tb(III)-MOF with Lewis Basic Pyridyl Sites for the Highly Sensitive Detection of Metal Ions and Small Molecules

A new luminescent terbium–metal–organic framework [Tb₃(L)₂(HCOO)­(H₂O)₅]·DMF·4H₂O (1) (H₄L = 4,4′-(pyridine-3,5-diyl)­diisophthalic acid) has been successfully assembled by Tb³⁺ ions and an undeveloped pyridyl-tetracarboxylate. Compound 1 exhibits a 3D porous (3,8)-connected (4.5²)₂(4².5¹².6⁶.7⁵.8³) topological framework with fascinating 1D open hydrophilic channels decorated by uncoordinated Lewis basic pyridyl nitrogen atoms. In particular, the Tb-MOF (1) can detect Cu²⁺ ions with high selectivity and sensitivity, and its luminescence is nearly entirely quenched in N,N-dimethylformamide (DMF) solution and biological system. In addition, 1 still has high detection for the trace content of nitromethane with 70 ppm, which suggests that 1 is a promising example of dual functional materials with sensing copper ions and nitromethane.