Unearth the Luminescence Potential of Metal–Organic Frameworks: Adopting a Feasible Strategy to Fabricate One Ratiometric Fluorescence Sensor for Monitoring Both 1-Hydroxypyrene and Cu2+

In this work, a novel luminescent hybrid material with double emission centers (Eu(TTA)0.2@9-1-UMOF) is successfully prepared, adopting a feasible design strategy. Initially, the second ligand 1,2,4-benzenetricarboxylic acid (H3BTC) is encapsulated based on a solid solution approach, which effectively improves the ligand-based emission intensity of the original LMOF and provides functional sites for introducing the second luminescent center; then, Eu3+ as the red emission source is loaded into the frameworks through a coordination post-synthetic modification method; finally, to balance the emission intensity at 613 nm (Eu3+) and 465 nm (1,4-naphthalenedicarboxylic acid (H2NDC)), 2-thenoyltrifluoroacetone (TTA) as a powerful antenna is introduced. Given the outstanding luminescence properties and structural stability of Eu(TTA)0.2@9-1-UMOF, it is further developed as a ratiometric sensor for detecting 1-hydroxypyrene (1-HP, the biomarker of polycyclic aromatic hydrocarbons (PAHs)) and Cu2+, which promotes the pre-diagnosis of human health. Notably, Eu(TTA)0.2@9-1-UMOF exhibits excellent selective recognition ability for both 1-HP and Cu2+ with high sensitivity (LOD = 4.06 × 10-6 mg/mL, 3.85 × 10-7 mol/L, respectively) and fast response speed. In addition, Eu(TTA)0.2@9-1-UMOF as a fluorescent probe shows great potential for the determination of 1-HP and Cu2+ in actual samples. More importantly, this work widens the road for the development of dual/multiple LMOF-based sensors for analytical applications.