Metal-Free Hydrosilylation Polymerization by Merging Photoredox and Hydrogen Atom Transfer Catalysis

Organosilicon compounds and polymers have found wide applications as synthetic building blocks and functional materials. Hydrosilylation is a common strategy toward the synthesis of organosilicon compounds and polymers. Although transition-metal-catalyzed hydrosilylation has achieved great advances,...

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Veröffentlicht in:Journal of the American Chemical Society 2021-11, Vol.143 (45), p.19167-19177
Hauptverfasser: Huang, Zhujun, Chen, Zhe, Jiang, Yuan, Li, Ning, Yang, Shicheng, Wang, Guowei, Pan, Xiangcheng
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Sprache:eng
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Zusammenfassung:Organosilicon compounds and polymers have found wide applications as synthetic building blocks and functional materials. Hydrosilylation is a common strategy toward the synthesis of organosilicon compounds and polymers. Although transition-metal-catalyzed hydrosilylation has achieved great advances, the metal-free hydrosilylation polymerization of dienes and bis­(silane)­s, especially the one suitable for both electron-rich and electron-deficient dienes, is largely lacking. Herein, we report a visible-light-driven metal-free hydrosilylation polymerization of both electron-rich and electron-deficient dienes with bis­(silane)­s by using the organic photocatalyst and hydrogen atom transfer (HAT) catalyst. We achieved the well-controlled step-growth hydrosilylation polymerizations of the electron-rich diene and bis­(silane) monomer due to the selective activation of Si–H bonds by the organic photocatalyst (4CzIPN) and the thiol polarity reversal reagent (HAT 1). For the electron-deficient dienes, hydrosilylation polymerization and self-polymerization occurred simultaneously in the presence of 4CzIPN and aceclidine (HAT 2), providing the opportunity to produce linear, hyperbranched, and network polymers by rationally tuning the concentration of electron-deficient dienes and the ratio of bis­(silane)­s and dienes to alter the proportion of the two polymerizations. A wide scope of bis­(silane)­s and dienes furnished polycarbosilanes with high molecular weight, excellent thermal stability, and tunable architectures.
ISSN:0002-7863
1520-5126
DOI:10.1021/jacs.1c09263