The use of halogen-containing cobalt and iron(II) clathrochelates in the radical polymerization of methyl methacrylate and styrene

Islamova, Regina M.; Ishkinina, O. I.; Nazarova, Svetlana V.; Voloshin, Ya. Z.; Belov, Alexander S.; Bubnov, Yu. N.

doi:10.1134/s0012500812110067

Cited by 1 publication

(3 citation statements)

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“…The effect of macrobicyclic cobalt(II) tris-α-dioximates with alkyl, aryl, and halide side substituents 30-34 (Scheme 10) on radical polymerization of vinyl monomers has been studied in [91,92]. Regardless of the used initiator type, the introduction of cobalt(II) clathrochelates in polymerization of methyl methacrylate and styrene has led to the character of the controlled macrochain growth: complete degeneration of the gel effect, the linear dependence of M n on the monomer conversion, the decrease in the polydispersity index down to M w /M n = 1.8 at a high conversion, and overall deceleration of the process with the increased concentration of the additives.…”

Section: Methodsmentioning

confidence: 99%

“…In order to elucidate the effect of the central metal ion of the clathrochelate on radical polymerization process, iron compounds with halide substituents 35-37 (Scheme 11), similar to the cobalt complexes, has been studied [92]. The iron(II) complexes has been recognized as fairly inert towards polymerization as compared to the cobalt analogs (as reflected in the kinetic curves and the molecular mass of the products).…”

Section: Methodsmentioning

confidence: 99%

“…A new type of catalysts, ferrocenyl-containing iron(II) semi-and clathrochelates, remarkable for the presence of ferrocenyl fragment (or fragments) in the clathrochelate scaffold 20-29 (Scheme 9) has been suggested in [87][88][89][90][91][92]. The choice of such structure of the complex has been inspired by the presence of highly reactive ferrocenyl group [33,55,63] as well as by the special ligand type, macrocyclic clathrochelate with iron(II) as the central atom.…”

Section: Methodsmentioning

confidence: 99%

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Iron compounds in controlled radical polymerization: Ferrocenes, (clathro)chelates, and porphyrins

Islamova

2016

Russ J Gen Chem

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Abstract-Experimental data on the application of metal complexes in radical polymerization of vinyl monomers collected over the recent 15 years have been analyzed and generalized. Special attention has been given to (un)substituted ferrocenes, macrocyclic (clathro)chelates, and iron porphyrinates as well as to the approaches to enhance their catalytic activity in controlled synthesis of macromolecules. The mentioned systems have been compared with each other as well as with selected complexes of other transition metals. It has been shown that the electronic and spatial structures of the metal complexes are related to their efficiency in the radical polymerization reactions. Keywords: controlled radical polymerization, metallocene, (clathro)chelate, metal porphyrinate, catalytic/ initiating system Application of metal complexes opens broad prospects to control the polymerization processe and to prepare polymer materials with improved physicochemical properties. The metal complex catalysis has become of special importance in the field of controlled radical polymerization over the recent 15 years.The term "controlled radical polymerization" is generally referred to "living" or "pseudo-living" radical polymerization; its mechanism, irrespectively of the type of the catalysts/mediators applied (metal complexes [1-11], nitroxyl compounds [12-14], thioesters [15,16], etc.) is based on minimization of the probability of the interaction between the propagating radicals, resulting in the irreversible chain termination. This allows for control of molecular parameters of the prepared polymers, in particular, reduction of the polydispersity coefficient down to M w /M n = 1.1, achieving the linear behavior of the number-average molecular mass (M n ) as function of the conversion, elimination of the undesirable gel effect, and preparation of block copolymers.Atom Transfer Radical Polymerization (ATRP) [1], Transition Metal-Catalyzed Living Radical Polymerization [7], and Organometallic Mediated Radical Polymerization (OMRP) [11] are among the types of controlled radical polymerization. The first approach is based on the use of halides of organic complexes of transition metals, leading to the formation of labile terminal carbon-halogen bond (P n -Hlg). Under certain conditions, this bond is capable of dissociation to regenerate the initial or new active radical further propagating the polymer chain (Scheme 1).Here P n · stands for the propagating macroradical, М is the vinyl monomer, HlgMt x+1 /L is the metal complex halide (with L as the organic ligand), Mt is the transition metal, and k p is the rate constant of the chain propagation.The second of the listed methods uses stable radical organometallic species or diamagnetic transition metal complexes forming the carbon-metal bond P n -Mt as the regulators of the polymer chain growth [11] (Scheme 2).Due to the similarity of these two approaches their simultaneous operation is often assumed [11].Besides "living" radical polymerization, complexand/or coordination-radical polymeri...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%