(S)-Binaphthalene-based fluorescence polymer sensors for direct and visual F− detection

(S)-binaphthalene-based polymer sensors P-1 and P-2 could be synthesized by the polymerization of 5,5′-((2,5-dibutoxy-1,4-phenylene)bis(ethyne-2,1-diyl))bis-(2-hydroxy-3-(piperidin-1-ylmethyl) benzaldehyde (M-1) with (S)-2,2′-dimethoxy-(1,1′-binaphthalene)- 6,6′-diamine (M-2) and (S)-2,2′-dimethoxy-(1,1′-binaphthalene)-3,3′-diamine (M-3) via nucleophilic addition–elimination reaction. The fluorescence emission of P-1 and P-2 could exhibit gradual enhancement behavior upon the addition of F−. Compared with other anions, such as Cl−, Br−, I−, HSO 4 − , ClO 4 − , H 2 PO 4 − , AcO−, and NO3−, F− could lead to the most remarkable fluorescence enhancement as high as 3.67-fold for P-1 and 12.85-fold for P-2, respectively. More importantly, both two polymer sensors P-1 and P-2 can display a bright yellow fluorescence color change for F− under a commercially available UV lamp, which could be clearly observed by the naked eyes for direct visual detection of F−.