Next Generation Living Coordinative Chain Transfer Polymerization for Functional Materials and Molecules

Abstract

Polyolefins (POs) are the most widely produced plastic in the world due to the large range of applications that can be met by materials derived from such a small set of olefin monomers like propene and ethylene. Over the last quarter century, the Sita group has contributed to the field of polymer chemistry with their processes of living coordinative polymerization (LCP) and living coordinative chain transfer polymerization (LCCTP) of α-olefins and α,ω-nonconjugated dienes. The latter process utilizes a small set of cyclopentadienyl, amidinate (CPAM) group 4 metal pre-initiators of the form (η5-C5R5)[κ2-(N,N)-N(R1)C(R2)N(R3)]MMe2 that are used in combination with a main group metal alkyl chain transfer agent (CTA). This small arsenal has shown itself to be powerful in its range of polyolefin materials it can produce, showing tremendous control over molar mass, tacticity, and select end group incorporation. However, challenges in the production of some select materials and molecules exist that cannot be met by the technology of the current generation. This document will serve to showcase the next generation of LCP and LCCTP that provide access to new polyolefins and polyolefin derivatives by making use of newly developed pre-initiators and CTAs. It will be shown that end group functionalized POs can be produced through LCP initiated by novel hafnium-phenyl bond insertion. Additionally, the reduction of non-bonded steric interactions within the supporting CPAM ligand environment will prove to be beneficial for LCP and LCCTP with challenging metals and monomers. Lastly, the realization of a new polymerization technique, living ternary chain transfer telomerization (LTCTT), has given access to valuable molecules through versatile and scalable green chemistry.