Highly selective and sensitive long fluorescence lifetime polyurethane foam sensor based on Tb-complex as chromophore...

Developing novel rare-earth complexes to rapidly and reliably sensing anions in pure water is highly challenging. Here, a series of long fluorescence lifetime polyurethane foam bonded Tb(BAA)₃ chromophore porous material (Tb-PUFs) have been designed and synthesized via a simple one-step co-polycondensation reaction as an efficient fluorescent sensor for H₂PO₄^- in pure water. All Tb-PUFs exhibited strong green emission and long fluorescence lifetime in water, which was ascribed to Tb-complex can be dispersed very well in polyurethane foam, effectively avoiding the emission quenching of Tb³⁺ ions caused by water molecules vibration. The titration experimental results showed that precursor Tb(BAA)₃ can effective recognize F^-, CH₃COO^-, and H₂PO₄^- in DMSO solution. Interestingly, Tb-PUFs can only selectively recognize H₂PO₄^- in pure water, this phenomenon can be explained that H₂PO₄^- is acidic, and can occur deprotonation with -NH group of ligand BAA, thus making the fluorescence quenching effect was more sensitive for H₂PO₄^- in pure water. In addition, the sensing ability of Tb-PUFs for H₂PO₄^- is highly reversible by washing them with deionized water for three times. In a word, all results implied that Tb-PUFs was an excellent candidate for H₂PO₄^- ions detection selectively in pure water.