Aqueous nanodispersion of acetylene tethered, quinoxaline-containing conjugated polymer as fluorescence probe for Ag+

Abstract

A type of carbazole-based, quinoxaline-containing conjugated polymer with tethered acetylene groups, P-2, was successfully synthesized through the desilylation of triisopropylsilyl (TIPS) protected precursor polymer. A nanodispersion of P-2 in water was prepared by reprecipitation treatment and displays acceptable quantum efficiency (QE, 0.20). Optical properties of P-2 in THF solution and nanodispersion state were characterized by UV-vis and photoluminescence (PL) analyses. Specific binding with Ag⁺ of P-2 was validated by UV-vis and PL analyses against other metal ions. The corresponding results suggest that P-2 possesses selectivity and sensitivity toward Ag⁺. Around 82% of the PL intensity of P-2 was quenched when the concentration of Ag⁺ in the probing mixture reached ∼5.1 × 10⁻⁴ M. The detection limit for Ag⁺ was evaluated as ∼64 nM (S/N = 3). The synergic effect of the tethered acetylenes and N atoms in the quinoxaline segments interacting with Ag⁺ is the possible reason for the specific response of P-2 for Ag⁺.