Kim Jeongeun, Kang Eun-Hye, Choi Tae-Lim
Department of Chemistry, Seoul National University, Seoul 151-747, Korea.
ACS Macro Lett. 2012 Aug 21;1(8):1090-1093. doi: 10.1021/mz300250b. Epub 2012 Aug 13.
Recently, the importance of Meldrum's acid has been reinvestigated because it serves as a great precursor for ketene generation by thermolysis. In this study, we synthesized conjugated polymers containing Meldrum's acid via controlled cyclopolymerization using a third-generation Grubbs catalyst. To avoid the solubility issue, copolymerization with soluble monomers was successfully used to provide various random and block copolymers containing Meldrum's acid in the conjugated backbone. Interestingly, when a polyacetylene derivative containing Meldrum's acid was incorporated into the second block of the diblock copolymers, highly stable core-shell supramolecules spontaneously formed during the polymerization via in situ nanoparticlization of conjugated polymer. This direct fabrication of nanostructures without requiring any post-treatments was due to the strong π-π interactions and the insolubility of the polyacetylene segment leading to the formation of core in situ. Moreover, thermolysis of Meldrum's acid to generate ketene in the conjugated polymer core was monitored by IR, and its consecutive cycloaddition to afford the cross-linked core improved the stability of the supramolecules.
最近，丙二酸亚异丙酯的重要性已被重新研究，因为它是通过热解生成乙烯酮的优质前体。在本研究中，我们使用第三代格拉布催化剂通过可控环聚合反应合成了含有丙二酸亚异丙酯的共轭聚合物。为避免溶解性问题，成功采用与可溶性单体共聚的方法，以提供在共轭主链中含有丙二酸亚异丙酯的各种无规共聚物和嵌段共聚物。有趣的是，当将含有丙二酸亚异丙酯的聚乙炔衍生物引入二嵌段共聚物的第二个嵌段时，在聚合过程中通过共轭聚合物的原位纳米颗粒化自发形成了高度稳定的核壳超分子。这种无需任何后处理即可直接制备纳米结构的方法，是由于强π-π相互作用以及聚乙炔链段的不溶性导致原位形成核。此外，通过红外光谱监测了共轭聚合物核中丙二酸亚异丙酯热解生成乙烯酮的过程，并且其连续的环加成反应以提供交联核提高了超分子的稳定性。
