A Highly Efficient Catalyst for the Synthesis of Alternating Copolymers with Thieno[3,4-c]pyrrole-4,6-dione Units via Direct Arylation Polymerization

详细信息    查看全文

• 作者：Masayuki Wakioka ; Nobuko Ichihara ; Yutaro Kitano ; Fumiyuki Ozawa
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：January 28, 2014
• 年：2014
• 卷：47
• 期：2
• 页码：626-631
• 全文大小：334K
• ISSN：1520-5835

文摘

蟺-Conjugated polymers with a donor鈥揳cceptor (DA) combination of repeating units possess a narrow HOMO鈥揕UMO gap, thus resulting in a high device performance in solar cells. This paper reports an improved catalytic system for the synthesis of DA polymers containing 5-(2-hexyldecyl)-5H-thieno[3,4-c]pyrrole-4,6-dione-1,3-diyl (TPD) group as the acceptor unit via palladium-catalyzed direct arylation polymerization. Although a related study has been reported ( Angew. Chem. Int. Ed. 2012, 51, 2068), we attempted to reduce the catalyst loading because the palladium residue in 蟺-conjugated polymers has been known to produce a detrimental effect on device performance. As a result, the amount of palladium could be reduced to 1/8 by using PdCl₂(MeCN)₂ and P(C₆H₄-o-OMe)₃ (L1) as catalyst precursors. The polymerization smoothly proceeds at 100 掳C in THF in the presence of pivalic acid and Cs₂CO₃ to afford TPD-based DA polymers 3a鈥?b>3d containing the following donor units in almost quantitative yields: 4,4鈥?dioctyl-2,2鈥?bithiophene-5,5鈥?diyl (3a, M_n = 36800, M_w/M_n = 2.20), 4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b鈥瞉dithiophene-2,6-diyl (3b, M_n = 31100, M_w/M_n = 2.44), 3,4-(2,2鈥?dioctylpropylenedioxy)thiophene-2,5-diyl (3c, M_n = 68200, M_w/M_n = 3.04), and 2,5-bis(2-ethylhexyloxy)-1,4-phenylene (3d, M_n = 65500, M_w/M_n = 2.21). A detailed analysis of the structure of 3a is reported.