Water‐soluble hyperbranched polyelectrolytes with high fluorescence quantum yield: Facile synthesis and selective chemosensor for Hg²⁺ and Cu²⁺ ions

Abstract

Abstract New water‐soluble hyperbranched polyfluorenes bearing carboxylate side chains have been synthesized by the simple “A2 + B2 + C3” protocol based on Suzuki coupling polymerization. The linear polyfluorene analogue LPFA was also synthesized for comparative investigation. The optical properties of the neutral precursory polymers in CHCl 3 and final carboxylic‐anionic conjugated polyelectrolytes in buffer solution were investigated. The obtained hyperbranched polyelectrolyte HPFA2 with lower content of branch unit (2%) showed excellent solubility and high fluorescence quantum yield (ϕ F = 89%) in aqueous solution. Fluorescence quenching of HPFA2 by different metal ions was also investigated, the polyelectrolyte showed high selectivity for Hg 2+ and Cu 2+ ions relative to other various metal ions in buffer solution. The Stern‐Volmer constant K sv was determined to be 0.80 × 10 6 M −1 for Hg 2+ and 3.11 × 10 6 M −1 for Cu 2+ , respectively, indicating the potential application of HPFA2 as a highly selective and sensitive chemosensor for Hg 2+ and Cu 2+ ions in aqueous solution. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3431–3439, 2010