Department of Materials and Chemistry and Biochemistry, Center for Polymers and Organic Solids, University of California, Santa Barbara, California 93106, United States.
J Am Chem Soc. 2011 Aug 17;133(32):12600-7. doi: 10.1021/ja202877q. Epub 2011 Jul 27.
Water-soluble conjugated polymers with controlled molecular weight characteristics, absence of ionic groups, high emission quantum yields, and end groups capable of selective reactions of wide scope are desirable for improving their performance in various applications and, in particular, fluorescent biosensor schemes. The synthesis of such a structure is described herein. 2-Bromo-7-iodofluorene with octakis(ethylene glycol) monomethyl ether chains at the 9,9'-positions, i.e., compound 4, was prepared as the reactive premonomer. A high-yielding synthesis of the organometallic initiator (dppe)Ni(Ph)Br (dppe = 1,2-bis(diphenylphosphino)ethane) was designed and implemented, and the resulting product was characterized by single-crystal X-ray diffraction techniques. Polymerization of 4 by (dppe)Ni(Ph)Br can be carried out in less than 30 s, affording excellent control over the average molecular weight and polydispersity of the product. Quenching of the polymerization with [2-(trimethylsilyl)ethynyl]magnesium bromide yields silylacetylene-terminated water-soluble poly(fluorene) with a photoluminescence quantum efficiency of 80%. Desilylation, followed by copper-catalyzed azide-alkyne cycloaddition reaction, yields a straightforward route to introduce a wide range of specific end group functionalities. Biotin was used as an example. The resulting biotinylated conjugated polymer binds to streptavidin and acts as a light-harvesting chromophore to optically amplify the emission of Alexa Fluor-488 chromophores bound onto the streptavidin. Furthermore, the biotin end group makes it possible to bind the polymer onto streptavidin-functionalized cross-linked agarose beads and thereby incorporate a large number of optically active segments.
具有受控分子量特性、不存在离子基团、高荧光量子产率和能够进行广泛范围选择性反应的末端基团的水溶性共轭聚合物，对于提高它们在各种应用中的性能是理想的，特别是荧光生物传感器方案。本文描述了这种结构的合成。2-溴-7-碘芴与 9,9'-位的八（乙二醇）单甲醚链，即化合物 4，被制备为反应性前体。设计并实施了高产率的有机金属引发剂（dppe）Ni（Ph）Br（dppe=1,2-双（二苯基膦基）乙烷）的合成，所得产物通过单晶 X 射线衍射技术进行了表征。4 通过（dppe）Ni（Ph）Br 的聚合可以在不到 30 s 内完成，从而可以极好地控制产物的平均分子量和多分散性。用[2-（三甲基甲硅烷基）乙炔基]溴化镁对聚合进行猝灭，得到荧光量子效率为 80%的硅烷乙炔端基水溶性聚芴。脱硅烷化，然后进行铜催化的叠氮-炔环加成反应，提供了一种直接引入广泛范围的特定末端基团功能的方法。生物素被用作例子。所得的生物素化共轭聚合物与链霉亲和素结合，并作为光收集发色团，光学放大结合在链霉亲和素上的 Alexa Fluor-488 发色团的发射。此外，生物素末端基团使得能够将聚合物结合到链霉亲和素功能化的交联琼脂糖珠上，并从而掺入大量光学活性片段。
