Synthesis of heteroatom end-functionalized polyethene with lanthanide and transition-metal catalysts

Incorporation of heteroatom functionalities in the catalytic formation of polyolefin materials can be accomplished either by copolymerization of the olefin with an olefinic substrate that has a heteroatom-containing substituent, or by using a heteroatom-containing chain-transfer agent. In the first case the functionalities introduced are located in side-groups on the polyolefin backbone, in the second case the functionality will cap the polymer on one end of the chain. The latter strategy has been applied recently using chain-transfer agents with reactive X-H bonds (X = Si, B) in conjunction with group 3 and group 4 metal catalysts. We have sought to apply the capacity of lanthanide metallocenes to perform ethene polymerization as well as C-H activation to this chemistry, using heteroatom-containing hydrocarbons with activated C-H bonds as chain-transfer agents, and to compare this with analogous cationic group 4 metallocenes