Chiral sensing of Eu(III)-containing achiral polymer complex from chiral amino acids coordination induction.

ABSTRACT The β-diketonate-based achiral polymer P-1 could be synthesized by the polymerization of 3,7-dibromo-2,8-dimethoxy-5,5-dioctyl-5 H-dibenzo[b,d]silole ( M1) with ( Z)−1,3-bis(4-ethynylphenyl)−3-hydroxyprop-en-1-one ( M2) via typical Sonogashira coupling reaction. The β-diketonate unit in the main chain backbone of P-1 can further coordinate with Eu(TTA) x [TTA− = 4,4,4-trifluoro-1-(thiophen-2-yl)butane-1,3-dionate anion, X = 1, 2, 3] to afford corresponding Eu(III)-containing polymer complexes. The resulting achiral polymer complex P-2 ( X = 2) can exhibit strong circular dichroism (CD) response toward both N-Boc- l and d-proline enantiomers. The CD signal was preliminarily attributed to coordination induction between chiral N-Boc-proline and the Eu(III) complex moiety. The linear regression analysis of CD sensing shows a good agreement between the magnitude of molar ellipticity and concentration of chiral N-Boc- l or d-proline, which indicates this kind Eu(III)-containing achiral polymer complex can be used as a chiral probe for enantioselective recognition of N-Boc- l or d-proline enantiomers based on Cotton effect of CD spectra. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3080-3086 [ABSTRACT FROM AUTHOR]