Precision Synthesis of Various Low‐Bandgap Donor–Acceptor Alternating Conjugated Polymers via Living Suzuki–Miyaura Catalyst‐Transfer Polymerization

Abstract

Herein, we demonstrate that living Suzuki-Miyaura catalyst-transfer polymerization (SCTP) using a RuPhos Pd G3 precatalyst is a versatile method for the precision synthesis of various donor-acceptor alternating conjugated polymers (DA ACPs). First, the living SCTP of biaryl monomers with combinations of both medium to strong A and D were optimized to produce DA ACPs with controlled number average molecular weight (M n ), narrow dispersity (Ð, 1.05-1.29), and high yield (> 87 %). Moreover, its expansion to controlled polymerization (M n = 9.2-40.0 kg mol À 1 ) of an A 1 -D-A 2 -D quateraryl monomer containing diketopyrrolopyrrole (DPP; strong A) was successful. The living SCTP also enabled the efficient one-pot synthesis of various diblock and triblock copolymers. Lastly, the DA ACPs showed tunable optical band gap (E g opt , from 1.29 to 1.77 eV) and highest occupied molecular orbital (HOMO) level (from À 5.57 to À 4.75 eV), while their block copolymers exhibited broad absorption ranges and promising visible light-harvesting properties.

Highly Efficient Preparation of Length and Width-Controllable Donor–Acceptor Nanoribbons via Polymerization-Induced Crystallization-Driven Self-Assembly of Fully Conjugated Block Copolymers

“…39 An intriguing observation was the emergence of a vibrational shoulder at 617 nm, suggesting the formation of some self-assembled structures driven by π−π interactions of thiophene rings. 24 Also, dynamic light scattering (DLS) analysis of an in situ aliquot from the polymerization solution revealed a sharp peak at D h = 342 nm, (10,20), (10,30), (20,20), (20,30), (20,40), and (30, 30) (Table 1, entries 7−13). Their absorption spectra shown in Figure 2d revealed two distinct peaks at 381 and 482 nm, corresponding to PQX and P3PT blocks, respectively.…”

“…One major barrier to the CDSA of D–A BCP has been the lack of a versatile living polymerization method for their synthesis. To be specific, conventional chain-growth polymerizations of CPs, such as Kumada catalyst-transfer polymerization, were not effective to achieve living polymerization of various acceptor-type monomers, although they are excellent for donor units like thiophene or fluorene. − To solve this issue, our group recently established a universal Suzuki–Miyaura catalyst-transfer polymerization (SCTP) by employing Buchwald-type precatalysts and boronate tuning strategies, thereby significantly expanding the scope and applicability. , As a result, the living polymerization of both donor and acceptor monomers became possible to give even complex microstructures such as alternating or BCPs, − thereby offering the access to key BCPs for the CDSA of D–A nanostructures.…”