Synthesis and Fluorescent Properties of a Chiral Conjugated Polymer Based on (<i>S</i>)-2,2′-Binaphtho-20-crown-6
作者:Hui Huang、Qian Miao、Yixiong Kang、Xiaobo Huang、Jinqian Xu、Yixiang Cheng
DOI:10.1246/bcsj.81.1116
日期:2008.9.15
Linear conjugated polymer was obtained by the polymerization of 2,3-dibutoxy-1,4-diethynylnaphthalene (M-1) and (S)-5,5′-dibromo-6,6′-dibutyl-2,2′-binaphtho-20-crown-6 (S-M-2) via Pd-catalyzed Sonogashira reaction. The conjugated polymer shows strong green-blue fluorescence due to the extended π-electronic structure between the chiral repeating unit (S)-6,6′-dibutyl-2,2′-binaphtho-20-crown-6 and the conjugated linker 2,3-dibutoxynaphthyl group via acetylene bridge. The responsive properties of the chiral polymer on K+, Pb2+, Hg2+, and AsIII were investigated by fluorescent spectra. The results show that Hg2+ and AsIII can cause effective fluorescent quenching of the polymer, whereas, K+ and Pb2+ do not produce obvious changes in the polymer fluorescence. The obvious fluorescent influence shows that the 2,2′-binaphtho-20-crown-6 moiety plays an important role in fluorescent recognition for Hg2+ and AsIII due to the effective photoinduced electron transfer (PET) and charge transfer (PCT) between the conjugated polymer backbone and receptor species.
2,3- 二丁氧基-1,4-二乙炔基萘(M-1)和(S)-5,5′-二溴-6,6′-二丁基-2,2′-联萘-20-冠醚-6(S-M-2)通过钯催化的 Sonogashira 反应聚合而成线性共轭聚合物。由于手性重复单元(S)-6,6′-二丁基-2,2′-联萘-20-冠醚-6 与共轭连接体 2,3-二丁氧萘基之间通过乙炔桥具有扩展的 π 电子结构,因此共轭聚合物显示出强烈的绿蓝色荧光。通过荧光光谱研究了手性聚合物对 K+、Pb2+、Hg2+ 和 AsIII 的响应特性。结果表明,Hg2+ 和 AsIII 能有效淬灭聚合物的荧光,而 K+ 和 Pb2+ 则不会使聚合物的荧光发生明显变化。明显的荧光影响表明,2,2′-联萘-20-冠-6 分子在 Hg2+ 和 AsIII 的荧光识别中发挥了重要作用,这是由于共轭聚合物骨架与受体物种之间有效的光诱导电子转移(PET)和电荷转移(PCT)所致。