Synthesis of Semicrystalline Polyolefin Materials: Precision Methyl Branching via Stereoretentive Chain Walking

We report the discovery
of C2-symmetric
nickel catalysts capable of the regio- and isoselective polymerization
of 1-butene to produce isotactic 4,2-poly­(1-butene), a new semi-crystalline
polyolefin. The catalyst exhibits enantioface selectivities as high
as 84% and the resulting polymers display melting temperatures up
to 86 °C. This system marks a rare example of preserving stereochemistry
through a chain walking polymerization process.