Influence of Metal Identity and Complex Nuclearity in Kumada Cross-Coupling Polymerizations with a Pyridine Diimine-Based Ligand Scaffold

作者：Andrew J. King, Jiashu Wang, Tianchang Liu, Adharsh Raghavan, Neil C. Tomson, Aleksandr V. Zhukhovitskiy · 发表于：ACS Polymers Au · 年份：2023 · DOI：10.1021/acspolymersau.3c00022 · 被引用次数：2 · 研究领域：Organoboron and organosilicon chemistry、Catalytic Cross-Coupling Reactions、Organometallic Complex Synthesis and Catalysis

High Resolution Image Download MS PowerPoint Slide Cross-coupling polymerizations have fundamentally changed the field of conjugated polymers (CPs) by expanding the scope of accessible materials. Despite the prevalence of cross-coupling in CP synthesis, almost all polymerizations rely on mononuclear Ni or Pd catalysts. Here, we report a systematic exploration of mono- and dinuclear Fe and Ni precatalysts with a pyridine diimine ligand scaffold for Kumada cross-coupling polymerization of a donor thiophene and an acceptor benzotriazole monomers. We observe that variation of the metal identity from Ni to Fe produces contrasting polymerization mechanisms, while complex nuclearity has a minimal impact on reactivity. Specifically, Fe complexes appear to catalyze step-growth Kumada polymerizations and can readily access both Csp 2 –Csp 3 and Csp 2 –Csp 2 cross-couplings, while Ni complexes catalyze chain-growth polymerizations and predominantly Csp 2 –Csp 2 cross-couplings. Thus, our work sheds light on important design parameters for transition metal complexes used in cross-coupling polymerizations, demonstrates the viability of iron catalysis in Kumada polymerization, and opens the door to novel polymer compositions.