A multifunctional metal-organic framework showing excellent fluorescence sensing and sensitization

Abstract Luminescent metal-organic frameworks (LMOFs) have been widely used as sensors and sensitizers for some chemical species due to their functional sites and porosity. In this work, a new metal–organic frameworks, [Cd 2 (H 2 L) 2 (H 2 O) 5 ] . 5H 2 O . 2DMF ( 1 ), has been successfully synthesized using 2,5-bis-(3,5-dicarboxyphenyl)thiopheneamide (H 4 L) under solvothermal condition. Single crystal X-ray diffraction analysis reveals that 1 has a basic tetranuclear unit, in which H 4 L is incompletely deprotonated. Furthermore, the basic tetranuclear units are connected into 3D supramolecular network by hydrogen bonds and π-π stacking interactions. As expected, the participation of the fluorescent ligand H 4 L endows 1 with a strong fluorescence emission. Thus, we systematically explored the fluorescence sensing responses of 1 to small organic molecules and metal ions. Notably, complex 1 can act as a potential multifunctional fluorescence material for sensing of p -nitroaniline and Fe 3+ ion with high stability, selectivity and sensitivity. In addition, complex 1 also protects Eu 3+ cations from solvent quenching and sensitizes encapsulated Eu 3+ hydrates emitting in the UV–vis region. This work highlights the practical application of luminescent MOFs as sensors and sensitizers.