Synthesis of carbazole-based dendritic conjugated polymer: a dual channel optical probe for the detection of I- and Hg2.

Abstract

A new type of carbazole-based blue-emitting dendritic conjugated polymer, poly[(9,9-dioctyl)-2,7-fluorene-co-4,4',4"-triphenylamine-co-9-(4-(9H-carbazol-9-yl)butyl)-3,6-carbazole](P), was successfully synthesized by Suzuki coupling reaction. Chemical structures of monomers and polymer were verified by FI-IR and ¹HNMR characterizations. We found that polymer showed a special selectivity and high sensitivity for I^-. With the addition of I^-, the fluorescent polymer solution was obviously quenched. The polymer showed a special detection effect on I^-. However, the fluorescent polymer was obviously restored when Hg²⁺ was added to the P/I^- system due to the large complexation between I^- and Hg²⁺. The anti-interference experiments of probe P/I^- showed that other background cations have a slight influence on detecting Hg²⁺, and the calculated detection limit of Hg²⁺ reached 9.7 × 10^-8 M, which could be a potential application for a two-channel cyclic detection of I^- and Hg²⁺. Additionally, it was found that the theoretical values were in agreement with the experimental data.