Toward Defect Suppression in Polythiophenes Synthesized by Direct (Hetero)Arylation Polymerization

Abstract

In this study, we have investigated different reaction conditions for defect suppression in polythiophene derivatives synthesized by direct (hetero)arylation polymerization (DHAP). The well-known PQT12 polymer was used as a model due to its simple structure which facilitated analysis. 2-Bromo-3,4′-didodecyl-2:2′,5′:2″,5″:2‴-quaterthiophene and 2-bromo-3″,4‴-didodecyl-2:2′,5′:2″,5″-2‴-quaterthiophene monomers allowed the analysis of both homocoupling defects and β-branching defects due to their asymmetric structure as well as the effect of β-protection. The properties of the resulting polymers were analyzed using sizeexclusion chromatography, differential scanning calorimetry, UV− visible absorption spectroscopy, and 1 H NMR spectrometry. Some model compounds were synthesized to help with end-groups analysis, revealing debromination as the main obstacle to chain growth. The highest quality polymer was obtained when using toluene as a solvent, Pd 2 dba 3 as a palladium(0) catalyst, neo-decanoic acid (NDA) as a carboxylic acid additive, and a dual-ligand system with diamine TMEDA and phosphine P(o-OMePh) 3 . This study also revealed the importance of the choice of the monomers for the preparation of well-defined conjugated polymers.

Direct Heteroarylation Guidelines for Well-Defined Thiophene-Based Conjugated Molecules

“…Generally, we believe the results described here provide key insight into direct (hetero)­arylation reactions and will be tested for different polymerization systems. Interestingly, another study performed by our group on direct (hetero)­arylation polymerization came to a similar conclusion regarding optimized reaction conditions …”

“…Interestingly, another study performed by our group on direct (hetero)arylation polymerization came to a similar conclusion regarding optimized reaction conditions. 32 ■ EXPERIMENTAL SECTION General Information. All reagents and chemicals compounds were purchased from Aldrich and used without any further purification.…”

Direct Arylation Polycondensation of Thiophene‐Based C−H Monomers†

“…recently conducted further research on two C−H monomers of M A5 and M A6 , which are the isomers of M A3 and M A4 , respectively. [ 61 ] M A5 has an alkyl chain on the β ‐position next to the bromine atom, whereas this alkyl chain is installed on the other side of the β ‐position for M A6 (closing to the C—H bond). Even though using N,N,N′,N′ ‐tetramethyl ethylenediamine (TMEDA) as the co‐ligand, bulky carboxylate additive NDA as the acid additive and Pd(0) pre‐catalyst Pd 2 (dba) 3 instead of Pd(II) pre‐catalyst in the catalytic system to avoid homo‐coupling and β ‐branching defects, the DArP of M A6 only yielded oligomers.…”

“…As shown in Figure 9, steric repulsion between the carboxylate ligand and the solubilizing alkyl side chains reduces the reactivity of undesired C—H bonds relative to the sterically accessible target C−H sites. This approach has been successfully employed for the syntheses of branching‐free PThs [ 54,57,60‐61,92‐95 ] and D‐A polymers. [ 122‐123 ]…”

Polyconjugated Materials for Printed (Opto)Electronics: Introducing Sustainability

“…57 Direct arylation methods are becoming increasingly competitive with Stille and SM, also for the manufacturing of polyconjugated molecules and polymers. [136][137][138][139][140][141][142] We exploited the direct (hetero)arylation polymerization (DHAP) approach for the synthesis of a polymeric latent pigment derivative, aimed at mimicking the transport properties of the very popular electron-transporting material poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2). [143][144][145][146][147] Scheme 4 Synthetic pathway leading to the luminescent radicals PyPBTM, Py-PNBTM, and PyPhBTM…”