Synthesis and characterization of pyrene-labeled poly(ethylenimine)
Synthesis and characterization of pyrene-labeled poly(ethylenimine)
复制标题
DOI：
10.1021/ma980672y
复制
发表时间：
1998-09
期刊：
影响因子：
5.5
通讯作者：
M. Winnik;and Simon M. Bystryak;Zhaoqing Liu;J. Siddiqui
中科院分区：
文献类型：
--
作者：
M. Winnik;and Simon M. Bystryak;Zhaoqing Liu;J. Siddiqui
通过1-芘甲醛还原胺化聚乙烯亚胺（PEI），制备了不同芘含量的PEI。芘标记的PEI（PEI-Py）的水溶液表现出典型的芘单体和激基缔合物发射，并且激基缔合物与单体的比率IE/IM随着大分子中Py含量的降低而降低。激基缔合物发射来自于预缔合芘聚集体。单体和激基缔合物的发射强度都随溶液pH值的降低而增加。溶液的pH从pH = 10降低至pH = 1.5导致IM增加约100倍，而IE仅增加2至3倍。该系统的一个主要特征是Py荧光被PEI的氨基猝灭。这种猝灭取决于这些基团的质子化程度。芘甲醇的模型实验表明，三乙胺在水中作为猝灭剂的效率是二乙胺的20倍，这意味着PEI中的大部分猝灭是在水中进行的。
Pyrene-labeled poly(ethylenimine) (PEI) containing different amounts of pyrene per polymer were prepared by reductive amination of PEI with 1-pyrenecarboxaldehyde. Aqueous solutions of the pyrene-labeled PEI (PEI−Py) exhibit typical pyrene monomer and excimer emission, and the excimer-to-monomer ratio IE/IM decreases with decreasing Py content of the macromolecule. The excimer emission arises from preassociated pyrene aggregates. Both the monomer and excimer emission intensities increase with decreasing pH of the solution. A decrease in pH of the solution from pH = 10 to pH ≈ 1.5 led to approximately a 100-fold increase in IM, whereas IE increased just 2- to 3-fold. A major feature of this system is the quenching of the Py fluorescence by amino groups of the PEI. This quenching depends on the degree of protonation of these groups. Model experiments with pyrenemethanol show that triethylamine is 20 times more effective as a quencher than diethylamine in water, implying that most of the quenching in PEI is ...