Discriminatory Photoactivation of Diastereomeric RAFT Agents

• DOI: 10.1021/acs.macromol.9b01534
• Publication Date: 2019-09-16T17:23:56Z
• Authors: Shiyang Lin; Lei Zhang; Zixuan Huang; Priyank V. Kumar; Jiangtao Xu
• Keywords: Raft; Chain transfer; Diastereomer; Living polymerization

Reversible deactivation radical polymerization (RDRP) techniques regulate free through a process of reversible activation/deactivation propagating radicals, which thus provides dormant polymer chains with unique capping moieties (alkoxyamine, halogen, thiocarbonylthio, etc.) as chain ends. The ends are the reactive sites initiation, propagation, and termination, therefore their chemical structures crucial for mechanism kinetics RDRP. investigation stereochemical effects is challenging due to limited models that highly accessible able represent long chains. Herein, we employ single unit monomer insertion (SUMI) technology prepare ideal (oligomeric macro-RAFT agents) effect on photoactivation. Two diastereomeric agents were prepared in high yield by SUMI, then photoactivated photoinduced electron/energy transfer-reversible addition- fragmentation chain-transfer (PET-RAFT) under visible light. Discriminatory activation was observed one diastereomer much faster than other. mechanistic explanation such interesting behavior suggested aid quantum calculations. Higher C–S bond dissociation energy greater stability contributed slower photoactivation RAFT compared