文献类型：期刊文献

英文题名：Preparation of conjugated polyphenylenes from maleimide-based enediynes through thermal-triggered Bergman cyclization polymerization

作者：Sun, Shiyuan[1];Zhu, Chuanchuan[1];Song, Depeng[1];Li, Fei[1];Hu, Aiguo[1]

机构：[1]E China Univ Sci & Technol, Sch Mat Sci & Engn, Shanghai Key Lab Adv Polymer Mat, Shanghai 200237, Peoples R China

年份：2014

卷号：5

期号：4

起止页码：1241

外文期刊名：POLYMER CHEMISTRY

收录：;EI(收录号：20140517252528);WOS:【SCI-EXPANDED(收录号:WOS:000331343100016)】；

基金：The support from National Natural Science Foundation of China (91023008), Ph. D. Programs Foundation of Ministry of Education of China (20100074110002), the Fundamental Research Funds for the Central Universities, and Shanghai Leading Academic Discipline Project (B502) is gratefully acknowledged. AH thanks Dr Ting Wu for her valuable comments on MALDI-TOF analysis.

语种：英文

外文关键词：Electron spin resonance spectroscopy - Conjugated polymers - Mass spectrometry - Cyclization - Nuclear magnetic resonance spectroscopy - Spectrum analysis

摘要：Several maleimide-based enediynes are synthesized through Sonogashira coupling reactions between 3,4-diiodo-N-benzylmaleimide (3) and para-substituted phenylacetylenes (5). All these enediynes undergo thermal-triggered Bergman cyclization at elevated temperature (130-160 degrees C) as revealed by DSC analysis. Conjugated polyphenylenes (7) are obtained by simply heating these enediynes (6) under vacuum. The occurrence of Bergman cyclization is evidenced by IR and NMR spectroscopy. The conjugated polyphenylenes are further characterized by UV-vis and MALDI-TOF mass spectroscopy (MS). Isotope pattern analysis on the MS spectra of the conjugated polyphenylenes shows that the chain ends of the polymers consist of a considerable amount of unmasked free radicals. EPR spectroscopy of the conjugated polyphenylenes confirms the existence of free radicals, which slowly fade away probably by removing active atoms (like hydrogen or halogen) from the environment.