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 NaBH4. 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. [ABSTRACT FROM AUTHOR]