Mixed-Ligand Approach to Palladium-Catalyzed Direct Arylation Polymerization: Highly Selective Synthesis of π-Conjugated Polymers with Diketopyrrolopyrrole Units

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• 作者：Masayuki Wakioka ; Rina Takahashi ; Nobuko Ichihara ; Fumiyuki Ozawa
• 刊名：Macromolecules
• 出版年：2017
• 出版时间：February 14, 2017
• 年：2017
• 卷：50
• 期：3
• 页码：927-934
• 全文大小：486K
• ISSN：1520-5835

文摘

The combined use of P(2-MeOC₆H₄)₃ (L1) and TMEDA as ligands effectively prevents defect formation in palladium-catalyzed direct arylation polymerization (DArP) to give donor–acceptor type alternating copolymers (DA polymers) with diketopyrrolopyrrole (DPP) units. The reaction of 3,6-bis(5-bromo-2-thienyl)diketopyrrolopyrrole (1-Br) and 3,4-dicyanothiophene (2-H) in toluene at 100 °C for 6 h in the presence of only L1 afforded a notable amount of insoluble materials via branching and cross-linking; in addition, the soluble part (M_n = 3100) included a large quantity of homocoupling defects (12.5%). In contrast, in the presence of L1 and TMEDA, the formation of insoluble materials was completely suppressed, and homocoupling defects decreased to 1.6%. Furthermore, the molecular weight of poly(1-alt-2) remarkably increased (M_n = 24 500, 97% yield). The mixed ligand catalyst using L1 and TMEDA was also effective against DArP of 1-Br with thienopyrroledione (3-H) or 3,4-propylenedioxythiophene (4-H) to afford DA polymers with DPP units in high yields (poly(1-alt-3): M_n = 36 800, 100% yield; poly(1-alt-4): M_n = 19 000, 80% yield). Thermal and optical properties of the resulting polymers are reported.