The recent developments in organoborane initiated C1 polymerization (chain grows by one atom at a time) of ylides opens unique horizons towards well-defined/perfectly linear polymethylenes (equivalent to polyethylenes, PE) and PE-based complex macromolecular architectures. The general mechanism of C1 polymerization (polyhomologation) involves the formation of a Lewis complex between a methylide (monomer) and a borane (initiator), followed by migration/insertion of a methylene into the initiator and after oxidation/hydrolysis to afford OH-terminated polyethylenes. This review summarizes efforts towards conventional and newly discovered borane-initiators and ylides (monomers), as well as a combination of polyhomologation with other polymerization methods. Initial efforts dealing with C3 polymerization and the synthesis of the first C1/C3 copolymers are also given. Finally, some thoughts for the future of these polymerizations are presented.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the King Abdullah University of Science and Technology (KAUST) Professor Nikos Hadjichristidis would like to thank the former group members Postdoctoral fellow Dr Hefeng Zhang (currently, Assoc. Professor at Shantou University, China) and PhD student Nazeeha Alkayal (currently Assist. Professor, King Abdulaziz University, Saudi Arabia) for their contribution to the polyhomologation project. The help of Martyn Merriees, internship student from the University of Strathclyde, Glasgow, in the Lab is gratefully acknowledges.