Lewis Pair Polymerization: Perspective on a Ten-Year Journey

Abstract

Ten years have passed since the conception of what was termed Lewis pair polymerization (LPP) that employs Lewis acid and base in pairs to not only activate monomers but also effect chain initiation, propagation, and transfer events. Compared to other polymerization methodologies, LPP's cooperative and synergistic two-component catalytic mechanism empowers several unique or advantageous features, including extraordinary tunability of catalyst/ initiator systems, compounded thermodynamic and kinetic control over comonomer sequences in one-pot LPP of monomer mixtures for highly resolved block copolymers, complete chemoselectivity in LPP of multifunctional vinyl monomers, independent tuning of polymerization activity and target polymer molecular weight, controlled heat dissipation in bulk polymerization with unactivated monomers functioning as solvent molecules, and coupled selectivity and livingness with immortality of the active species to produce ultrahigh molecular weight polymers and block copolymers with record-number (53) blocks. Focusing on four fundamental attributes of any polymerization methodologymechanism, kinetics, control, and selectivitythis Perspective narrates the growth and development of LPP, tracing each innovation back to fundamental principles so that each concept can be strategically applied, and describes new frontiers fertile for future research.

Unimolecular Anion‐Binding Catalysts for Selective Ring‐Opening Polymerization of O‐carboxyanhydrides

“…A slow initiation relative to enchainment would lead to curved profiles with gradually ascending slopes [18] . In addition, the kinetics results revealed that the monomer activation in current system was weaker than that in Lewis pairs catalytic systems, [1k] where the kinetics obeyed zero‐order of monomer concentrations due to the strong monomer activation. The theoretical deduction of the chain propagation rate law was also in keeping with the above rate law and had first‐order dependence on [ 3 b ] and [M] t (see Figure S47 and Derivation of the propagation rate law).…”

Poly(ε-lysine) and its derivatives via ring-opening polymerization of biorenewable cyclic lysine

“…We expect that the combination of lowcost metal salts and organic bases to realize efficient ROP of lysine-derived ε-lactams is promising. 80,81 It is also a feasible approach to devise some amino functional groups without deprotection and obtain derivatives with similar functions to ε-PL. Considering the structural similarity of ε-PL and poly(caprolactam), we can foresee the copolymerization of caprolactam and cyclic lysine monomers to prepare antimicrobial fibers 82 and films, 83,84 which will attract extensive attention in both academia and industry.…”

Production and Polymerization of Biobased Acrylates and Analogs

“…Another emerging field in the polymerization of (meth)acrylates is the so‐called Lewis pair polymerization, recently reviewed by the Chen group. [ 333,350 ] The concept of frustrated Lewis pairs (FLPs) was first described by Stephan in 2008, [ 351 ] and applied to polymerization two years later, as Chen and co‐workers described alane‐based Lewis adducts with various encumbered Lewis bases as extremely active systems for the polymerization of MMA. [ 352 ] LPP relies on the activation of the (meth)acrylic monomer by the Lewis acid and subsequent nucleophilic attack of the activated monomer by the Lewis base.…”