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 unsubstituted 2,2′-bithiophene units. When only L1 is used as a ligand, the reaction of 5,6-difluoro-4,7-bis[5-bromo-4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5]thiadiazole (1a-Br) with 2,2′-bithiophene (2-H) in toluene at 100 °C forms a notable amount of insoluble materials via branching and cross-linking. In contrast, in the presence of L1 and TMEDA, the formation of insoluble materials is completely suppressed, and PffBT4T [poly(1a-alt-2)] with a well-controlled structure and high molecular weight is obtained (M_n = 88100). Similarly, the reaction of 5,10-bis[5-bromo-4-(2-decyltetradecyl)thiophene-2-yl]naphtho[1,2-c:5,6-c′]bis[1,2,5]thiadiazole (1b-Br) with 2-H in toluene at 110 °C forms PNTz4T[poly(1b-alt-2)] with M_n = 43800. The resulting polymers function as good components of bulk-heterojunction type organic solar cells (OSCs) using PC₇₁BM. In particular, PNTz4T performs the best of all the DArP polymers reported so far (PCE = 9.0(1)%).

中文翻译：

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钯催化的直接芳基化聚合的混合配体方法：包含未取代的联噻吩单元的给体-受体聚合物的合成

P（2-MeOC ₆ H ₄）₃（L1）和TMEDA作为配体的组合使用可有效防止钯催化的直接芳基化聚合（DArP）中的缺陷形成，从而生成具有未取代2的供体-受体型交替共聚物（DA聚合物） ，2'-联噻吩单元。当仅L1用作配体时，5,6-二氟-4,7-双[5-溴-4-（2-辛基十二烷基）噻吩-2-基]苯并[ c ] [1,2， 5]噻二唑（1a-Br）与2,2'-联噻吩（2-H）在甲苯中的温度在100°C下通过支化和交联形成大量不溶物。相反，在存在L1的情况下与TMEDA一起，完全抑制了不溶物的形成，得到了结构良好且分子量高的PffBT4T [poly（1a - alt - 2）]（M _n＝ 88100）。类似地，5,10-双[5-溴-4-（2-癸基十四烷基）噻吩-2-基]萘[1,2- c：5,6- c ']双[1,2,5噻二唑（1b-Br）与2-H在甲苯中于110°C形成PNTz4T [poly（1b - alt - 2）]，其中M _n=43800。使用PC ₇₁ BM ，所得聚合物可作为体异质结型有机太阳能电池（OSC）的良好成分。特别是，到目前为止，PNTz4T在所有DArP聚合物中表现最佳（PCE = 9.0（1）％）。