Fully-water-soluble BODIPY containing fluorescent polymers prepared by RAFT method for the detection of Fe3+ ions

Abstract

The development of water-soluble polymer dyes is of great practical and scientific significance. In this article, small fluorescent molecule boron-dipyrromethene (BODIPY) bearing C=C bond was synthesized first. And then, via Suzuki reaction, recognition groups were introduced into the 2, 6 positions of BODIPY. Thus polymerizable fluorescent monomers were prepared. Finally, methacrylic acid (MAA) was copolymerized with the as-prepared small molecular fluorescent monomers via reversible addition-fragmentation chain transfer (RAFT) polymerization methodology. Four fully-water-soluble polymer sensors with BODIPY moieties in the end of the polymer chain were obtained eventually. In the presence of long PMAA chain, and by the assistance of it, BODIPY could be dissolved totally in water. These polymer sensors exhibited sensitive and selective recognition ability to Fe3+. Even the content rate of BODIPY was as low as 0.5% of the polymer (calculated from element analysis), the detection limit could reach 1.2 μM. The sensors with two recognition groups in one BODIPY unit were more sensitive than that with one recognition groups in each BODIPY unit. The sensing mechanism was investigated as well. By endowing the water solubility to organic sensors, the application scope could be greatly enlarged in sensing metal ions in aqueous environments. This work provides a method to develop water soluble high performance polymer sensors.