Synthesis of donor-acceptor conjugated polymers based on benzo[1,2-b:4,5-b′]dithiophene and 2,1,3-benzothiadiazole via direct arylation polycondensation : towards efficient C-H activation in nonpolar solvents

• Main Authors: Wang, Xiaochen, Wang, Mingfeng
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Chemistry::Organic chemistry::Polymers
• Online Access: https://hdl.handle.net/10356/103451; http://hdl.handle.net/10220/24513
• Institution: Nanyang Technological University

This article describes the synthesis of donor–acceptor (D–A) type copolymers based on benzo[1,2-b:4,5-b′]dithiophene and 2,1,3-benzothiadiazole via direct-arylation cross-coupling polycondensation. To achieve high performance polymerization, we have systematically investigated the reaction factors including catalysts, solvents, ligands, bases, additives, concentration of reactants and phase transfer agents. In particular, 1,2-dimethylbenzene (ODMB), as a nonpolar high boiling point solvent, is a superior medium to perform this direct-arylation polymerization. In this nonpolar aromatic solvent, Pd2dba3/(o-MeOPh)3P, accompanied with a base potassium carbonate and an additive pivalic acid, serves as an efficient catalyst system to obtain high-quality polymers. Our optimized condition gave the polymer with a weight-average molecular weight (Mw) as high as 60 kg mol−1 in nearly quantitative yield and excellent C–H selectivity.