A New Chiral Binaphthalene‐Based Fluorescence Polymer Sensor for the Highly Enantioselective Recognition of Phenylalaninol

A new ( S )‐binaphthalene‐based polymer ( P ‐ 1 ) was 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)‐3,3′‐diamine ( M ‐ 2 ) through the formation of a Schiff base; the corresponding chiral polymer ( P ‐ 2 ) could be obtained by the reduction of polymer P ‐ 1 with NaBH 4 . Chiral polymer P ‐ 1 exhibited a remarkable “turn‐on” fluorescence‐enhancement response towards ( D )‐phenylalaninol and excellent enantioselective recognition behavior with enantiomeric fluorescence difference ratios ( ef ) as high as 8.99. More importantly, chiral polymer P ‐ 1 displays a bright blue fluorescence color change upon the addition of ( D )‐phenylalaninol under a commercially available UV lamp, which can be clearly observed by the naked eye. On the contrary, chiral polymer P ‐ 2 showed weaker enantioselective fluorescence ability towards the enantiomers of phenylalaninol.