Core-First Synthesis of Three-Armed Star-Shaped Polymers by Rare Earth Metal-Mediated Group Transfer Polymerization

Abstract

Addressing polymer topologies is one of the key methods for tailoring polymer properties. Herein, we report for the first time on the core-first synthesis of three-armed star-shaped polymers with adjustable molecular weights via rare earth metal-mediated group transfer polymerization (REM-GTP). Based on the versatility of REM-GTP, enabling polymerization of a broad variety of functional monomers not accessible via conventional techniques, a novel and fast method toward directed polymeric structures was established. Therefore, the trinuclear catalyst was synthesized by 3-fold C–H bond activation of 1,3,5-tris(3,5-dimethyl-4-pyridinyl)benzene using Cp2YCH2TMS(THF) as precursor complex. Kinetic investigations in comparison to monometallic Cp2Y(sym-collidinyl) on the polymerization of diethyl vinylphosphonate (DEVP) and 2-isopropenyl-2-oxazoline (IPOx) evidenced activity of all three metal centers. However, in REM-GTP generally occurring incomplete initiation provoked by the interaction of initiators and mono...