Ligand-Mediated Modulation of Energy Transfer in a Dy-Based MOF for Ratiometric Discrimination of Tetracyclines and Proton Conduction

Lanthanide metal−organic frameworks (Ln-MOFs) integrate the characteristic f−f luminescence of rare-earth ions with high chemical stability, structural diversity, and functional tunability, rendering them promising platforms for multifunctional applications including luminescence sensing and proton conduction. Herein, we report the hydrothermal synthesis of a Dy-based MOF, denoted as Dy-TPTZ-MOF, constructed via a dual-ligand strategy employing tris(o-carboxyphenyl)phosphine oxide [tri-(o-H3BPO)] and 2, 4, 6-tri(2-pyridyl)-1, 3, 5-triazine (TPTZ) as coligands. In contrast to the Dy-MOF assembled solely from Tri-(o-H3BPO), the Dy-TPTZ-MOF exhibits dual-channel luminescence, which arises from the antenna effect of the TPTZ ligand, enabling efficient ligand-to-metal energy transfer and sensitization of Dy3+ centers. Benefiting from the synergistic contributions of the aggregation-caused quenching and absorption enhancement effects, the Dy-TPTZ-MOF enables highly selective and sensitive ratiometric luminescence detection of tetracycline antibiotics. Furthermore, principal component analysis demonstrates that the material can effectively discriminate tetracycline antibiotics from structurally related antibiotics. In addition, the framework and abundant hydrogen-bonding interactions endow the material with excellent proton conductivity, reaching 5.60 × 10−3 S·cm−1 at 343 K and 98% relative humidity. This work provides a general strategy for the rational design of multifunctional Ln-MOFs with integrated sensing and proton-transport properties.