Synthesis and selective recognition toward zinc ion of chiral poly(imine‐triazole)

A novel AB type of clickable monomer, (S)‐2‐(2‐azido‐1‐phenylethylimino)methyl]‐5‐propargyloxyphenol (AMPP) was designed and polymerized to yield a class of main‐chain chiral poly(imine‐triazole)s through the metal‐free click reaction. With the thermally induced polymerization, the desired polytriazoles can be easily prepared in high yields by a stepwise heating‐up process and have the number‐average molecular masses ranging from 5.1 × 10³ to 58.1 × 10³ (polydispersity indices = 1.38?1.68). The polymers were characterized by Fourier Transform Infrared spectroscopy (FTIR), ¹H Nuclear Magnetic Resonance (NMR), and gel permeation chromatography, and their optical properties were studied by fluorescence and circular dichroism (CD) spectroscopies. As a chemosensor, these polymers exhibited a selective “turn‐on” fluorescence enhancement response toward Zn²⁺ ion over other cations such as Na⁺, K⁺, Mg²⁺, Ca²⁺, Ag⁺, Pb²⁺, Cd²⁺, Hg²⁺, Mn²⁺, and Ni²⁺ in dimethyl sulfoxide. However, the Zn²⁺‐induced fluorescence signal was subject to serious interference by Al³⁺, Cu²⁺, Cr³⁺, and Fe³⁺ ions. Interestingly, the chiral polymer showed distinctive changes in the CD spectra on complexation with Zn²⁺, which allowed for the discrimination of this ion in the presence of other species tested including those interfering ions observed in the fluorescent detection. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2248–2257