Guest inducing fluorescence switching in lanthanide–tris((4-carboxyl)phenylduryl)amine frameworks integrating porosity and flexibility

By employing the nanosized tris((4-carboxyl)phenylduryl)amine ligand to assemble with Ln3+ ions, a series of 2-fold interpenetrating lanthanide–organic frameworks (LnOFs; Ln = Y, Eu–Yb; FIR-16 to FIR-24) and heterometallic EuxTby–LnOFs (x + y = 2; FIR-25 to FIR-27) possessing the novel (3,6)-connected topology have been generated. FIR-17 with a high surface area of 941 m2 g−1 is an interesting flexible framework. Reversible fluorescence switching upon the presence or removal of guest molecules with different sizes is observed by using FIR-17 as a promising solvent sensor. This work presents an outstanding integration of photoluminescent properties and porosity for flexible lanthanide–organic frameworks.