Introduction of Highly Tunable End-Groups in Polyethylene via Chain-Transfer Polymerization using a Cobalt(III) Catalyst

Highly tunable end-functionalized polyethylene molecules are directly synthesized via chain-transfer polymerization of ethylene with silanes as chain-transfer agents catalyzed by a pentamethyl cyclopentadienyl cobalt phosphite alkyl catalyst. A series of polymerizations and kinetic studies of the different elementary steps involved in the catalytic cycle were performed to establish the methodology and to gain a deeper understanding of the reaction mechanism. The rate of the chain transfer, and thus the polymer length, can be tuned independently by varying the silane concentration or substituents. The combination of a chain-transfer methodology with a late transition-metal-based catalyst makes this system more compatible to polar functionality. This is highlighted by the introduction of an organic dye as end group to yield a colored polyethylene material.