Elucidating the Role of Catalyst Steric and Electronic Effects in Controlling the Synthesis of π-Conjugated Polymers

Kumada catalyst transfer polymerization (KCTP) has been widely adopted to synthesize π-conjugated polymers for various electronic and biological applications. However, the scope of monomers that can be polymerized with control is generally limited to small electron-rich (hetero)cycles. Because control over polymer molecular weight, dispersity, and end-groups is intrinsically linked to intramolecular catalyst transfer, improved catalysts are necessary to broaden the scope of this important polymerization technique. In this study, we present a computational investigation of how ligand bite angle, steric substituent effects, and electronic substituent effects of Ni(phosphine) catalysts influence KCTP. Density functional theory is utilized to model the catalytic cycle, and catalyst design rules are proposed based on how specific ligand variations individually and cooperatively affect the fundamental steps of oxidative addition, transmetalation, reductive elimination, and ring walking. Recommendations are made...