Controlled Synthesis of an Alternating Donor-Acceptor Conjugated Polymer via Kumada Catalyst-Transfer Polycondensation

Kumada catalyst-transfer polycondensation was used to synthesize poly(5,6-difluorobenzotriazole-alt-4-hexylthiophene) (PFBTzHT), an alternating donor-acceptor conjugated polymer, in a controlled manner. Through a series of kinetic studies, a linear relationship between the monomer conversion and the molecular weight of the resulting polymer was observed while maintaining narrow polydispersities (Ds ≤ 1.4). Moreover, the M_n displayed a linear relationship with the initial monomer-to-catalyst feed ratio, and polymers with M_ns up to 25 kDa were successfully synthesized. All-conjugated block copolymers containing segments of PFBTzHT and poly(3-hexylthiophene) (P3HT) were also obtained in various compositions (30-70% P3HT) via sequential monomer addition in a single vessel.