Synthesis And Fluorescent Properties Of Chiral Polymer Sensors

Many investigations have been focused on the fluorescence sensor design and its application. The detection guest of fluorescence sensor includes neutral small molecules, chiral molecules, bio-molecules, some important cations and anions. The advantage of this method is its easy-operating, high sensitivity and selectivity. The advantage of polymer-based fluorescence sensors over small molecules lies in its signal amplification effect due to their rigid configuration and repeating unit in the backbone. Fluorescence polymers are designed for chiral molecules or metal ions detection, which serves as an important part for this paper.Section2:We designed and synthesized a versatile chiral polymer P1and P2based on (R,R)-1,2-diaminocyclohexane. We talked about the structures of the polymers according the CD spectra. Importantly. P2could play as a "turn-off" fluorescence sensor toward Cu(II), and the in situ generated (R,R)-Cu(Ⅱ)-P2can exhibit remarkable "turn-on" fluorescent enhancement response and considerable enantioselectivities toward Z-phenylglycinol via a ligand displace mechanism. This work can be applied for direct detection of phenylglycinol enantiomers by a simple, rapid, visual, sensitive and selective method.Section3:We have developed a novel BINAM-based helical chiral polymer, which exhibited remarkable "turn-on" fluorescence enhancement response toward trivalent metal cations (M3+, M=Al, Cr, Fe) over mono-and divalent metal cations. The solution of the polymer turns on bright blue fluorescence color upon the addition of trivalent metal cations under a commercially available UV lamp, this change can be clearly observed by the naked eyes for direct visual discrimination at low concentration. More importantly, the addition of trivalent metal cations lead to the most pronounced change of CD spectra indicating this kind chiral polymer can be used as a sole probe for selective recognition of trivalent metal cations according to CD spectra. Further study on the mechanism announced that the different fluorescence and CD response of the chiral polymer between trivalent metal cations and other metal cations due to the higher hydrolyzing ability of the M3+in water and the H+may play an important role in the recognition progress.