Synthesis of water-soluble, fluorescent, conjugated polybenzodiazaborole for detection of cyanide anion in water

A polymer sensor (P1) containing benzodiazaborole moieties for recognition of cyanide anion and sulfonate groups for water-solubility was synthesized by Suzuki cross-coupling polymerization, which enables cyanide detection in aqueous solution. The polymer showed visible fluorescence quenching upon exposure to cyanide anion concentrations as low as ∼2 μM. Selective detection of cyanide anions can be accomplished via fluorescence quenching, while other anions exhibited fluorescence enhancement upon exposure, mainly due to the difference in the nucleophilicity of anions, affecting benzodiazaborole group.