Synthesis of Chain Shuttling Organometallic Compounds Capable of Producing Triblock Polyolefins

Abstract

Organometallic oligomeric compounds with dual-headed structure R’-(M-R-)nM-R’ were developed enabling the synthesis of triblock polyolefins. The compounds comprise divalent linkers (R) derived from trivinylcyclohexane between two main group metals and norbornyl capping groups (R’). Due to the difference in steric hindrance, the chain transfer reaction in polymerization selectively involves the less hindered M–R bond, resulting in growth of polymer chains only from the R linker group with metals on both ends. The metal-terminated polymer can be further functionalized to form telechelic polymers or used in coordinative chain transfer polymerization to produce various triblock polyolefins. This paper presents the synthetic strategy and demonstrates the production of triblock polymers using the compounds in a scalable continuous solution polymerization process.