Homolytically weak metal-carbon bonds make robust controlled radical polymerizations systems for “less-activated monomers”
Résumé
This article is an account of work, mostly carried out in the authors' laboratory, on the use of organometallic compounds with homolytically fragile metal-carbon bonds as dormant species in the controlled radical polymerization of a variety of monomers in what is now universally called "organometallic-mediated radical polymerization" (OMRP). The article retraces a brief history of OMRP, shows how it can potentially intervene in every radical polymerization process based on atom transfer (ATRP), which is a more popular controlling method where the metal plays a catalytic role, and how it can be in competition with another catalyzed process involving chain transfer to monomer (CCT). It highlights the challenges of controlled radical polymerization in the area of the "less activated monomers" (LAMs) and particularly the problem of the monomer addition errors, demonstrating how ligand engineering and coordination chemistry constitute additional handles, not available to other moderating species, providing acceptable ad hoc solutions. It details how OMRP could achieve unsurpassed levels of control for two specific monomers: vinyl acetate (VAc) and vinylidene fluoride (VDF). Finally, it lays the principles for the development of efficient chain transfer catalysts for less activated monomers.
Origine : Fichiers produits par l'(les) auteur(s)
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