Iridium-catalyzed direct C-H amidation polymerization to give fluorescent polysulfonamides
- 자연과학대학 화학부
- Issue Date
- 서울대학교 대학원
- C-H activation; C-H amidation; polymerization; polysulfonamides; fluorescence; excited-state intramolecular proton transfer
- 학위논문 (석사)-- 서울대학교 대학원 자연과학대학 화학부, 2017. 8. 최태림.
- Polymerization methods via C-H activation have attracted great attention in recent years to synthesize various polymers such as polythiophenes, polycarbazoles, and rigid ladder polymers. The main advantages of them are reducing the undesired byproducts and the number of synthetic steps. However, conventional polymerizations via C-H activation are limited to C-C bond formation, and polymerization method for C-N bond formation via C-H activation has remained unexplored to date. We report a iridium-catalyzed direct C-H amidation polymerization (DCAP) that enables atom-economical, green method to synthesize polysulfonamides. It was discovered that reactive directing groups, additives, silver salts, concentrations, and reaction temperatures are key to optimize DCAP through model studies and optimizations. This polymerization allowed high molecular-weight (up to 149 kDa) and defect-free polysulfonamides using amides and various readily accessible bis-sulfonyl azides. Furthermore, these polymers emit blue light with large stokes shifts and high quantum yields due to excited-state intramolecular proton transfer (ESIPT) although these polymers have different structures from conventional fluorescent conjugated polymers. Notably, this research demonstrates an important lesson that the new polymerization can lead directly to the discovery of novel materials.