Mixed-Ligand Approach to Palladium-Catalyzed Direct Arylation Polymerization: Synthesis of Donor–Acceptor Polymers with Dithienosilole (DTS) and Thienopyrroledione (TPD) Units

Abstract

This paper reports the synthesis of an alternating copolymer consisting of dithienosilole (DTS) and thienopyrroledione (TPD) units via palladium-catalyzed direct arylation polymerization (DArP). Although DArP has recently attracted much attention as an easy synthetic method of π-conjugated polymers without the need for prepreparation of organometallic monomers, there are two major problems that must be eliminated. One is homocoupling producing structural defects in the polymer chain, and the other is byproduction of insoluble materials. In this study, we have found that the combined use of P­(2-MeOC6H4)3 and P­(2-Me2NC6H4)3 ligands effectively prevents these side reactions, resulting in poly­(DTS-alt-TPD) (M n GPC = 15000, M w/M n = 2.57) with good solubility in high yield (84%).

Balanced Ambipolar Poly(diketopyrrolopyrrole‐alt‐tetrafluorobenzene) Semiconducting Polymers Synthesized via Direct Arylation Polymerization

“…In addition, an extra peak at 7.41 ppm, which may possibly originate from M1–M1 homocoupling, was observed in the 1 H‐NMR spectra of both P1–3 and P1–5 (Figure S3, Supporting Information). Similar structural defects of homocoupling was also reported by other research groups in direct arylation polymerization of thiophene‐based monomers …”

Analysis of diverse direct arylation polymerization (DArP) conditions toward the efficient synthesis of polymers converging with stille polymers in organic solar cells

“…Due to being synthesized via Route X, we can reason that increased amounts of CBr/CBr homocouplings occurred. The mechanistic details of these homocoupling reactions is not fully understood but these may occur from the reduction of CBr bonds to CH bonds promoted by the palladium catalyst or disproportionation of the catalyst to form dimers . A1, generated at the lowest temperatures, showed the lowest content of homocoupling defects in class A. A3 had the most homocoupling defects, consistent with the highest catalyst loading (4%).…”

“…Lastly, the final two DArP conditions continue to feature phosphine ligands but from protocols derived from Ozawa et al Both Leclerc et al and Ozawa et al have shown success with P( o ‐NMe 2 Ph 3 ) 3 as an effective ligand for the synthesis of defect‐free copolymers . Through the incorporation of two ligands, P( o ‐NMe 2 Ph 3 ) 3 and P( o‐ anisyl) 3 , Ozawa et al produced copolymers based on dithienosilole and thienopyrroledione without defects . Despite the success of the dual ligand approach, P( o‐ anisyl) 3 has been successfully incorporated into different catalytic systems as the lone ligand .…”

“…This is advantageous because, as previously mentioned, the monomer purification for Route Y is easier and thus more suitable for large‐scale polymer synthesis. For these remaining studies, entry C1 is based on a study from Ozawa et al and was run in toluene with 0.5% Pd 2 (dba) 3 ·CHCl 3 loading, P( o‐ anisyl) 3 , NDA, and Cs 2 CO 3 . The phosphine:catalyst ratio was 8:1 and the monomer concentration was 0.40 M in toluene and reacted for 48 h at 100 °C.…”

Direct arylation polymerization toward efficient synthesis of benzo[1,2‐c:4,5‐c'] dithiophene‐4,8‐dione based donor‐acceptor alternating copolymers for organic optoelectronic applications

“…In the last decade, an alternative coupling method known as direct arylation has been extensively developed for a variety of building blocks to facilitate the direct polymerization of halogenated (bromo‐, iodo‐) and CH active aromatic monomers, thereby providing a synthetically facile and eco‐friendly alternative to conventional polymerizations . π‐Conjugated polymers synthesized by direct arylation polymerization (DAP) have shown impressive performance in optoelectronics as well .…”