Lanthanide-Coordinated Porous Polymer Organic Frameworks as Highly Luminescent Probes for Selectively Sensing of Alternaria Toxins

Although the rational design of multifunctional lanthanide-based frameworks and exploration of their emission mechanisms have long been research hotspots in the field of material science, they remain challenging issues that are critical to the development of optical sensing tools. Herein, a novel terbium-functionalized polymer organic framework (BTH-PHEN-POF@Tb) was successfully fabricated with benzene-1,3,5-tricarbohydrazide (BTH) and 1,10-phenanthroline-2,9-dicarbaldehyde (PHEN) as the building blocks. The as-prepared POF featured abundant imine bonds and nitrogen atoms allowing efficient coordination with Tb 3+ ions, which could activate a unique target-triggered synergistic antenna effect for Tb 3+ and effectively reduce solvent-induced nonradiative quenching, leading to a distinct and adjustable fluorescence enhancement. Density functional theory (DFT) calculations and frontier molecular orbital analysis were adopted for the explanation of fluorescence enhancement mechanism. A reliable fluorescent probe was developed for dual targets sensing of typical mycotoxins, tenuazonic acid (TeA) and alternariol monomethyl ether (AME). This detection method exhibited a wide linear range, high sensitivity (limits of detection = 1.51 for TeA and 0.15 ng mL −1 for AME), and rapid response (<30 s) along with excellent probe stability. Our results created new possibilities for the fabrication and application of multifunctional lanthanide-based frameworks in analytical chemistry, particularly for the optical sensing of harmful substances.