Recyclable heterogeneous palladium-catalyzed carbon–carbon coupling polycondensations toward highly purified conjugated polymers

• Published in: Journal of polymer research 2020, Vol.27 (1), Article 1
• Main Authors: Zou, Feihua, Yao, Fang, Liu, Limin, Cai, Mingzhong
• Format: Article
• Language: English
• Subjects: Carbon; Catalysts; Catalytic activity; Characterization and Evaluation of Materials; Chemical reactions; Chemical synthesis; Chemistry; Chemistry and Materials Science; Coupling; Industrial Chemistry/Chemical Engineering; Iron oxides; Leaching; Nanoparticles; Original Paper; Palladium; Polymer Sciences; Polymers; Reaction products; Recyclability; Silicon dioxide
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-019-1979-y

Conjugated polymers are usually synthesized by homogeneous palladium complexes-catalyzed Heck, Suzuki, and Stille coupling reactions, which suffer from the non- recyclability of expensive palladium catalysts and palladium contamination of the desired polymer due to palladium leaching. In order to overcome these drawbacks, a bidentate phosphino-modified magnetic nanoparticles-anchored palladium complex (PdCl 2 -Fe 3 O 4 @SiO 2 -2P) as a clean and efficient heterogeneous catalyst for the carbon–carbon coupling polycondensations was developed in present work. The PdCl 2 -Fe 3 O 4 @SiO 2 -2P catalyst exhibited an enhanced catalytic activity for Heck, Suzuki, and Stille coupling polymerizations, as compared with the most commonly used homogeneous Pd(PPh 3 ) 4 . Moreover, this heterogeneous palladium catalyst showed advantage of much less palladium impurity (below 13 ppm) in the isolated polymers. Importantly, PdCl 2 -Fe 3 O 4 @SiO 2 -2P can facilely be separated from the reaction products and recovered by using an external magnetic field, and recycled at least eight times with almost consistent catalytic activity.