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Organometallic-Mediated Radical Polymerization
Published in Samir H. Chikkali, Metal-Catalyzed Polymerization, 2017
Daniel L. Coward, Benjamin R. M. Lake, Michael Shaver
More recent work has focussed on using cobalt-mediated radical polymerization to synthesize poly(ionic liquid)s, a type of polyelectrolyte. Two different methods were used to polymerize various N-vinyl-3-alkylimidazolium-type monomers (Figure 6.8).48 The first method used 9 as a macroinitiator. The second method used [Co(acac)2] itself, along with tert-butylhydroperoxide (t-BuOOH) as initiator. In both cases, relatively low temperatures (30°C–50°C) were used with water as the solvent.
Organometallic-mediated radical polymerization using well-defined Schiff base cobalt(II) complexes
Published in Journal of Coordination Chemistry, 2018
Yan F. Silva, Beatriz A. Riga, Victor M. Deflon, Jhonathan R. Souza, Leonardo H. F. Silva, Antonio E. H. Machado, Pedro Ivo S. Maia, Carvalho-Jr Valdemiro P., Beatriz E. Goi
Schiff base complexes have been used as highly efficient catalysts for cyclopropanation, oxidation, epoxidation, Diels-Alder, and polymerization reactions [4, 12–21]. In particular, Schiff base cobalt complexes are an interesting class of compounds for mediating the polymerization of polar monomers including VAc (vinyl acetate) due to their less oxophilic nature relative to early transition metals. This monomer can be polymerized exclusively via a radical mechanism [22], so its “living” polymerization may only be considered using modern “living”/controlled radical polymerization (CRP) methodologies based on the reversible equilibrium between growing radicals and dormant species [23–27]. N2O2 Schiff base cobalt-mediated radical polymerization has been extended to VAc [28–30]. In a recent report, Peng and coworkers described the cobalt-mediated radical polymerization (CMRP) of both vinyl acetate and methyl acrylate using a Schiff base cobalt complex as controlling agent [29]. They reported a good control over the two polymerizations with the formation of polymers with low dispersities. Debuigne and coworkers replace the bidentate acac ligand for a tetradentate Salen type ligand in a one-pot process for improving the block copolymerization of vinyl acetate and n-butyl acrylate [31].