Synthesis and photophysical behaviors of a blue fluorescent copolymer as chemosensor for protons and Ni~(2+) ion in aqueous solution

摘要

An acrylic monomer bearing couamrin moiety, 7-hydroxy-4-methyl-8-(4'-acryloylpipera-zin-1'-yl) methylcoumarin (Ac-HMPC) was synthesized from 7-hydroxy-4-methyl-8-(4'-piperazin-1'-yl)methyl coumarin (HMPC) and acryloyl chloride (Ac) in the presence of triethylamine in dry dichloromethane (CH_2Cl_2) under 0℃. The synthesized Ac-HMPC was identified by FTIR, MS and ~1H NMR spectra, respectively. Then it was copolymerized with acrylamide (AM) using AIBN as initiator in THF under 70 ℃. The main photophysical properties of the fluorescent copolymer (poly(Ac-HMPC-co-AM)) were determined viewing its sensor for protons and metal cations. The fluorescent polymer displayed "on-off" switching in its fluorescence intensity over a wide pH scale. In addition, it was found the fluorescence enhancement of poly(Ac-HMPC-co-AM) in the presence of Ni~(2+) ion. The results suggest that copolymer may offer potential as a reusable polymer for sensor protons and Ni~(2+) ion in aqueous solution.