Meta-linked and para-linked water-soluble poly(arylene ethynylene)s with amino acid side chains: Effects of different linkage on Hg2+ ion sensing properties in aqueous media

Highly Sensitive Fluorescence Detection of Hg2+ Based on a Water-soluble Conjugated Polymer with Carboxylate Groups

A label-free, highly selective, and highly sensitive fluorescent sensor to detect Hg²⁺ was developed using a water-soluble conjugated polymer with carboxylate groups (poly(2,5-bis(sodium 4-oxybutyrate)-1,4-phenylethynylene-alt-1,4-phenyleneethynylene, PPE-OBS) in this work. The fluorescence of PPE-OBS would be quenched because of the effect among the unique coordination-induced aggregation and electron transfers of PPE-OBS toward Hg²⁺. The linear relationship between the fluorescence intensity and concentration of Hg²⁺ was observed within the range from 6 × 10^-8 to 8 × 10^-5 mol L^-1 (R² = 0.9985), and the limit of detection was 2.10 × 10^-9 mol L^-1. The proposed method was applied to detect Hg²⁺ in environmental water samples, and satisfactory results were obtained.

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

Novel poly(arylene ethynylene)s comprising a cinnoline core were prepared in high yields via a three-step methodology. A Richter-type cyclization of 2-ethynyl- and 2-(buta-1,3-diynyl)aryltriazenes was used for cinnoline ring formation, followed by a Sonogashira coupling for the introduction of trimethylsilylethynyl moieties and a sila-Sonogashira coupling as the polycondensation technique. The fluorescence of the cinnoline-containing polymers in THF was highly sensitive to quenching by Pd(2+) ions.