Polydiacetylenevesicles functionalized with N-heterocyclic ligands for metal cation binding
作者:D. Amilan Jose、Burkhard König
DOI:10.1039/b918452j
日期:——
Self assembled poly diacetylene (PDA) based blue vesicles LS-Terpy, LS-DPA, LS-DP and LS-DEA with metal chelating sites have been prepared and characterized. Their response to the presence of metal cations in buffered aqueous solution has been investigated by monitoring changes of colour, UV-Vis absorption and emission. The addition of zinc, manganese, cadmium, mercury or silver salts to solutions of the vesicles induces a colour change from blue to red observable by the naked eye, while the addition of other metal salts, containing ions like Li+, Na+, K+, Mg2+, Ca2+, Cr2+, Ni2+, Fe2+, Co2+, Cu2+ or Pb2+, failed to show any changes. The metal ion coordination selectivity of the ligands is slightly different for the vesicle surface immobilized ligands compared to the reported metal cation binding of the corresponding ligands in solution, which may be due to the special environment at the lipid–solution interface. The vesicles aggregate upon metal ion coordination to the embedded ligands as shown by dynamic light scattering (DLS) particle size analysis. The functionalized PDA vesicles retain their response to the presence of aqueous solutions of metal ions if immobilized in transparent polyvinyl alcohol films or on paper.
自组装的聚二乙炔(PDA)基蓝色囊泡LS-Terpy、LS-DPA、LS-DP和LS-DEA已被制备并表征。这些囊泡对缓冲水溶液中金属阳离子的存在反应的研究是通过监测颜色、紫外-可见吸收和发射的变化进行的。向囊泡溶液中添加锌、锰、镉、汞或银盐时,观察到颜色从蓝色变化为红色,这种变化是肉眼可见的;而添加其他金属盐(如锂离子、钠离子、钾离子、镁离子、钙离子、铬离子、镍离子、铁离子、钴离子、铜离子或铅离子)则未表现出任何变化。相对于溶液中对应配体与金属阳离子的结合,固态囊泡表面固定的配体对金属离子的配位选择性略有不同,这可能是由于脂质-溶液界面的特殊环境。囊泡在金属离子与嵌入的配体配位后发生聚集,动态光散射(DLS)颗粒大小分析显示了这一点。功能化的PDA囊泡在透明的聚乙烯醇薄膜或纸上固定后,仍然对金属离子的水溶液保持反应。