Catalyst-transfer polymerization of arylamines by the Buchwald–Hartwig cross-coupling

Abstract

The achievement of full control over the polymerization course of π-conjugated monomers in terms of monomer sequence, backbone length, and dispersity continues to represent a fascinating challenge in the field of polymer chemistry. Although the catalyst-transfer protocols have been successfully adapted for the obtainment of differently structured polymers employing specific monomers and reaction setups, an alternative scenario to the traditional C–C bond formation for the controlled growth of the polymer chain is thus far unexplored. In order to overcome this paradigm, we propose a synthetic protocol for the controlled polymerization of arylamines by the Buchwald–Hartwig cross-coupling, yielding poly(arylene–amine)s by the catalyst-transfer mechanism. Toward this aim, we conceived ad hoc AB-type monomers, in which the presence of suitable functional groups influences the polymerization course. The effect of these functional groups was supported by theoretical calculations, which not only ascertained the mechanistic pathway for the coordination of the monomer to the metal center but also pointed out the reductive elimination as the rate-determining step of the catalytic cycle. This study enriches the actual examples of catalyst-transfer polymerizations, paving the way for further structural diversifications of the π-conjugated backbones.