Although donor-acceptor alternating conjugated polymers (D-A ACPs) are highly potent organic semiconductor materials for device applications, the scope of controlled synthesis of them has been significantly limited. Herein, we report the precision syntheses of various D-A ACPs and their block copolymers were achieved through Suzuki-Miyaura catalyst-transfer polymerization (SCTP) using RuPhos Pd G3 precatalyst. Firstly, by combining medium to strong A (benzotriazole (BTz) and quinoxaline (QX)) with D (thiophene (Th), 3,4-ethylenedioxythiophene (EDOT), and selenophene (Se)), precision syntheses of four D-A ACPs (PBTzEDOT, PQXTh, PQXEDOT, and PQXSe) were obtained in controlled Mn, narrow dispersity (1.19-1.51), and high yield (&gt;87%). Also, the excellent ring-walking ability of RuPhos-Pd catalyst encouraged us to expand SCTP to a more complex target, a quateraryl monomer with diketopyrrolopyrrole (DPP; strong A) having carbonyl group, which prohibited conventional Kumada-Tamao CTP, to achieve controlled synthesis of an A1-D-A2-D terpolymer, PBTzThDPPTh (Mn = 9.2–40.0 kg/mol). Moreover, structural analysis via MALDI-TOF spectrometry and 1H NMR revealed the highly efficient external initiation followed by living chain-growth mechanism in SCTP. Furthermore, the living nature of SCTP also enabled efficient one-pot syntheses of various di(tri)block copolymers, including D-DA (P3HT-b-PQXTh), A-DA (PQX-b-PQXSe), DA-DA (PBTzEDOT-b-PQXTh), and A-D-DA (PQX-b-P3HT-b-PQXSe) via sequential addition method. Finally, optical and electrochemical analyses of the D-A ACPs showed their optical bandgap (Egopt) and highest occupied molecular orbital (HOMO) level were tunable in wide ranges (from 1.29 to 1.77 eV and from -5.57 to -4.75 eV, respectively) and their block copolymers have broad absorption ranges implying promising visible light-harvesting ability. These results highlight the superior catalyst-transfer ability of RuPhos-Pd along diverse arenes having dramatically different electronic densities and high functional group tolerance of SCTP.

Precision synthesis of various low-bandgap donor-acceptor alternating conjugated polymers via living Suzuki-Miyaura catalyst-transfer polymerization

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