Organometallic Mediated Radical Polymerization

Poli, Rinaldo

doi:10.1016/b978-0-12-803581-8.01353-9

Cited by 11 publications

(18 citation statements)

References 140 publications

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“…Extensive research and development of different reversible deactivation radical polymerization (RDRP) techniques over the last two decades has enabled the facile synthesis of macromolecules with a high degree of complexity and well-defined architectures [ 4 , 5 ]. Although nitroxide-mediated radical polymerization (NMP) [ 6 ], atom transfer radical polymerization (ATRP) [ 7 ], iodine-transfer polymerization (ITP) [ 8 , 9 , 10 ] and reversible addition-fragmentation chain transfer (RAFT) polymerization [ 11 , 12 , 13 , 14 , 15 ] have been comparatively more studied, organometallic-mediated radical polymerization (OMRP) [ 16 , 17 , 18 , 19 , 20 ] has recently emerged as a potent RDRP technique for the polymerization of “less activated monomers” (LAMs), such as vinyl imidazolium salts [ 21 , 22 ] or vinyl amides (such as vinyl pyrrolidone) [ 23 ]. Indeed, for these more difficult monomers, OMRP and, in particular, cobalt-mediated radical polymerization (CMRP) [ 24 ] has proven very efficient, opening synthetic routes for homopolymers and block copolymers that could only be prepared with a lower level of control or not at all by other RDRP techniques.…”

Section: Introductionmentioning

confidence: 99%

Bis(formylphenolato)cobalt(II)-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate

et al. 2017

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Abstract:The organometallic-mediated radical polymerization (OMRP) of vinyl acetate (VAc) and its OMR copolymerization (OMRcoP) with tert-butyl 2-trifluoromethylacrylate (MAF-TBE) mediated by Co(SAL) 2 (SAL = 2-formylphenolato or deprotonated salicylaldehyde) produced relatively well-defined PVAc and poly(VAc-alt-MAF-TBE) copolymers at moderate temperature (<40 • C) in bulk. The resulting alternating copolymer was characterized by 1 H-, 13 C-and 19 F-nuclear magnetic resonance (NMR) spectroscopies, and by size exclusion chromatography. The linear first-order kinetic plot, the linear evolutions of the molar mass with total monomer conversion, and the relatively low dispersity (Đ~1.55) of the resulting copolymers suggest that this cobalt complex provides some degree of control over the copolymerization of VAc and MAF-TBE. Compared to the previously investigated cobalt complex OMRP mediators having a fully oxygen-based first coordination sphere, this study emphasizes a few peculiarities of Co(SAL) 2 : a lower ability to trap radical chains as compared to Co(acac) 2 and the absence of catalytic chain transfer reactions, which dominates polymerizations carried in the presence of 9-oxyphenalenone cobalt derivative.

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Section: Introductionmentioning

confidence: 99%

Bis(formylphenolato)cobalt(II)-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate

et al. 2017

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“…When a radical polymerization is carried out using a halide‐free L/Mt x mediator, on the other hand, no ATRP may occur and any control is solely ensured by OMRP. [3a]…”

Section: General Principlesmentioning

confidence: 99%

“…Metal complexes, however, may react with the growing radical chains in various ways, each one affecting the control of chain growth either positively or negatively. The positive interplay between ATRP and a second method of metal‐mediated radical polymerization, known as “Organometallic‐Mediated Radical Polymerization” (OMRP) has been highlighted in a number of previous contributions . This Minireview will focus on the negative impact of two specific phenomena, one of which (Catalyzed Radical Termination, CRT) was discovered recently and the second one (Reductive Radical Termination, RRT), although well‐known in stoichiometric radical reactions, was only recently shown to interfere in ATRP‐type systems.…”

Section: Introductionmentioning

confidence: 99%

Impact of Catalyzed Radical Termination (CRT) and Reductive Radical Termination (RRT) in Metal‐Mediated Radical Polymerization Processes

et al. 2019

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Atom Transfer Radical Polymerization (ATRP), a metal‐catalyzed process, is a most powerful method for macromolecular engineering, producing polymers with targeted and low‐dispersity molar masses and with high chain‐end fidelity. This is due to the persistent radical effect, which dramatically reduces the spontaneous radical terminations, prolonging the lifetime of radical chains and the concurrent growth of all polymer chains. Two additional reaction modes that involve metals and organic radicals, however, may negatively affect the controlled polymerization. These are the Catalyzed Radical Termination (CRT) and the Reductive Radical Termination (RRT) and were shown to be particularly important for the polymerization of acrylate monomers. The scope and the mechanistic investigations carried out to elucidate how these processes interplay with ATRP and with each other are outlined in this Minireview.

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“…The use of transition metal complexes as moderating species in RDRP, generating an organometallic dormant species, whether operating by the RT or by the DT approach, has been termed "organometallic-mediated radical polymerization" (OMRP) [10] and a number of reviews have previously been published [11][12][13][14][15][16][17][18][19][20]. This article will retrace a few of the leading concepts and underline the specificity of the technique on the basis of a few of the most recent results.…”

Section: Controlled Radical Polymerization Also Known As Reversible mentioning

confidence: 99%

“…Since these early reports, many other cobalt(II)/alkylcobalt(III) systems able to promote polymer chain growth in a controlled fashion with low or no impact of CCT have been reported and, to this day, continue to dominate the OMRP research activity [11]. However, several other metals, particularly iron [16] but also molybdenum, titanium, vanadium and others, have been investigated as well [11][12][13][14][15][16][17][18][19]. Scheme 3.…”

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confidence: 99%

Homolytically weak metal-carbon bonds make robust controlled radical polymerizations systems for “less-activated monomers”

Fliedel

Poli

2019

Journal of Organometallic Chemistry

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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.

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Organometallic Mediated Radical Polymerization

Cited by 11 publications

References 140 publications

Bis(formylphenolato)cobalt(II)-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate

Bis(formylphenolato)cobalt(II)-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate

Impact of Catalyzed Radical Termination (CRT) and Reductive Radical Termination (RRT) in Metal‐Mediated Radical Polymerization Processes

Homolytically weak metal-carbon bonds make robust controlled radical polymerizations systems for “less-activated monomers”

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