Water soluble Ln(III)-based metallopolymer with AIE-active and ACQ-effect lanthanide behaviors for detection of nanomolar pyrophosphate

In this study, a polymerizable terpyridine 2-(4-(4-(4-vinylbenzyloxy)phenyl)-6-(pyridin-2-yl)pyridin-2-yl)pyridine was synthesized, with N-(2-hydroxyethyl)acrylamide (HEAA) used to obtain an amphipathic polymer (Poly) through free radical polymerization. Then, Poly was coordinated with LnCl₃ or Ln(ABM)₃(H₂O)₂ (ABM = 4,4,4-trifluoro-1-phenylbutane-1,3-dione; Ln = Eu or Gd) in an equimolar ratio and a series of terpyridine-based Ln(III)-metallopolymer Poly-Eu or Poly-Eu-ABM obtained. The results strongly suggested that Poly-Eu exhibited aggregation-induced lanthanide emission. In contrast, after the introduction of a secondary sensitizer, ABM to Poly-Eu, aggregation-caused quenching effects were observed in Poly-Eu-ABM. In addition, both Poly-Eu and Poly-Eu-ABM were applied as fluorescence sensors to selectively detect pyrophosphate (PPi) among a series of different anions and the detection limit found to be at the nanomolar scale. Furthermore, high PPi sensitivity and selectively, low toxicity, and water solubility of this metallopolymer matrix Poly-Eu-ABM were used to detect PPi in living cells.