ABSTRACT

A novel polymerization method, living coordinative chain transfer polymerization (CCTP), was recently developed with monocyclopentadienyl monoamidinate (CpAm) Group 4 metal complexes, which were previously applied for the traditional living coordination polymerization (TLCP) and stereomodulated degenerative transfer living (SDTL) coordination polymerization. In addition to a CpAm precatalyst and a cocatalyst, a chain transfer agent (CTA) was also added to the CCTP system. The CTA undergoes a rapid and reversible chain transfer with the Group 4 metal catalyst, which results in chain growth on an inexpensive main group metal alkyl. This new CCTP technique provides a practical solution towards the intrinsic problem, one chain per catalytic center, for a TLCP polymerization process. The first example of living CCTP was provided with ZnEt2 via (η5-C5Me5)HfMe2[N(Et)C(Me)N(Et)] (35) activated by [PhNHMe2][B(C6F5)4] (01). It was very efficient for the polymerization of ethene, propene, higher α-olefins and α,ω-nonconjugated dienes, and copolymerization of these monomers. The (co)polymers obtained possess very narrow polydispersity (PDI 1.03-1.10) an