Synthesis of polyhydroxybenzoxazole-based colorimetric chemosensor for anionic species

Poly[2-(2′-hydroxyphenyl)benzoxazole] is prepared by the two step procedures of Suzuki coupling polymerization with corresponding monomers followed by the deprotection of benzyl group. The polymer in dimethylformamide (DMF) solution is applicable to colorimetric sensing fluoride anion, which shows a color change from colorless to yellow. High sensitivity to fluoride anion compared to other anions such as phosphate, chloride, and sulfate is ascribed to the high coordination ability of the 2-(2′-hydroxyphenyl)benzoxazole moiety in the polymer chain.