Chiral discrimination of enantiomers based on different interactions with alterable chiral oligomer

Series of chiral oligomer ((S)-1-(S)-7)) based on the different proportions of achiral fluorophore unit (9, 9-dipropyl alkynyl fluorene (1a)) and chiral unit ((S)-2-(4-isopropyl-4, 5-dihydrooxazol-2-yl)-2-(prop-2-yn-1-yl) pent-4-ynenitrile (1b)) via Glaser coupling method were synthesized. The results showed that the fluorescent probe can be applied to the recognition of different enantiomers by changing the ratio of fluorophore to chiral group in the oligomer. The hydrogen bonding between chiral units and enantiomers in oligomers and large steric hindrance of rigid achiral units on conformation of the polymers may be the reasons for the different recognition abilities of oligomer with different ratios.