Monomers copolymerization metal containing

Well-defined nanoclusters (w 10-100 A diameter) of several metals have been prepared via the polymerization of metal-containing monomers. The synthetic approach involves the block copolymerization of a metallated norbornene with a hydrocarbon co-monomer which is used to form an inert matrix. Subsequent decomposition of the confined metal complex affords small clusters of metal atoms. For example, palladium and platinum nanoclusters may be generated from the block copolymerization of methyl tetracyclododecane (223) with monomers (224) and (225) respectively. 10,611 Clusters of PbS have also been prepared by treating the block copolymer of (223) and (226) with H2S.612 A similar approach was adopted to synthesize embedded clusters of Zn and ZnS 613,614... 

I, vinylruthenocene, 66, vinylosmocene, and the T)5-(vinylcyclopentadienyl)metal carbonyl monomers in radical-initiated polymerizations summarized in Scheme 1.1 no longer exists for anionically initiated addition polymerizations. Styrene is readily initiated by such anionic species as BuLi and Na1 Naphth. Living anionic styrene homopolymerizations and block copolymerizations have been extensively commercialized for many years (e.g., Kraton thermoplastic elastomers). However, the exceptionally electron-rich vinyl metal-containing monomers 1, 8-18, 24-30, and 66 were never successfully initiated by anionic systems in our laboratory despite many attempts. In these systems, the a-carbocations are very stable, but the a-carbanions are quite unstable. Thus, the addition of an anion to tbe vinyl function of these monomers is unfavorable. 

In essence, this is one of the variants of the copolymerization of metal-containing monomers with ethylene as analyzed above (see Chapter 4),... 

Highly interesting results are obtained from the study of polymerization and copolymerization of metal-containing monomers based on metals in different valence states (Chapter 4), but the correlation of the structure of the monomers and their reactivity is far from being understood. Also side reactions during... 

There are currently three basic approaches to the preparation of metal-containing polymers [12] as shown in Structnre 10.1 (I) reactions of metal compounds with fnnctionalized linear polymers in which the main polymer chain remains unchanged (so-called polymer-analogons conversions) (II) polycondensation of appropriate precursors, a process in which a metal ion is incorporated into the main chain, and its removal leads to destrnction of the polymer (III) polymerization and copolymerization of metal-containing monomers (recently devised approach) ... 

The incorporation of metal ions into a polymer chain—directly or via ligands— offers imique materials with properties that differ significantly from those of conventional organic polymers. The different range of coordination munbers especially of transition metal ions can allow the preparation of polymers with imusual conformational, mechanical, and morphological characteristics. All above considered types of MMCs can be also obtained by polymerization and copolymerization of metal-containing monomers. ... 

Type I A metal ion, a metal complex or metal chelate is connected with a linear or crosslinked macromolecule by covalent, coordinative, chelate, ionic or Ti-type bonds (Figure 1). This type I is realized by binding of the metal part at a linear, crosslinked polymer or at the outer or interior surface of an inorganic support. Another possibility uses the polymerization or copolymerization of metal containing monomers. 

POLYMERS OBTAINED BY COPOLYMERIZATION OF METAL-CONTAINING MONOMERS 172... 

Unfortunately, the aforementioned problems have not been adequately discussed in literature, although there is considerable interest in the preparation of structurally homogeneous macromolecular metal complexes for catalysis, photochemistry, biological applications, etc. This chapter reports on the specificity of the processes for formation of macromolecular complexes through both routes polymerlike transformations and copolymerization of metal-containing monomers. In addition, the predictive potential of reactions and the ways of preventing some of them will be discussed. 

Different valence states are also a fairly widespread type of unit variability. By analogy with macromolecular complexes (Section II), it may be expected that homopolymerization and copolymerization of metal-containing monomers would prevent or retard redox processes involving participation of metal ions. Experimental data confirm the fact that a polymeric matrix stabilizes complexes of metals in low oxidation states (e.g., Pd" ). Moreover, the stability of the Cu+ state during polymerization (including thermal polymerization) of copper acrylate controls the use of this method for the preparation of coordination compounds of Cu". The polymeric framework plays a stabilizing role, whereas the metal ions that are localized on the surface layer are oxidized to Cu +. However, polymerization of monomers that contain metal ions in high oxidation states is often accompanied by their reduction Fe + ->Fe +, and Mo + ->Mo" (scheme 14). For example, polymerization of Cu " and Fe + acrylates may be accompanied by intramolecular chain termination. This may be attributed to the relatively low standard reduction potentials of these metal ions (7io(Cu + Cu+) = 0.15, o(Fe ->Fe ) = 0.77 V). 

A rare case is copolymerization of several different MCMs. Ihe resulting polymers can contain mixed units of various types. This is particularly true for the development of high-temperature superconducting (HTSC) ceramics that are based on synthesized prepolymers. One of the methods that is used is the copolymerization of MCM acrylates (and perhaps maleinates) or acrylamide complexes ofY, Ba, or Cu and the synthesis of superconducting bismufli cuprates (e.g., Bi2Sr2Ca -i Cu 02n+4-5 where n = l-3) by copolymerization of the corresponding metal-containing monomers. Thermolysis of these polymeric precursors affords a finely... 

Vinylferrocene is one of the few transition-metal-containing monomers that will both homopolymerize and copolymerize with other vinyl monomers in the presence of free-radical initiators. 

Andrianov and Zhdanov have developed a method for the synthesis of polymers containing heterochain and carbon-chain units by free-radical copolymerization of metal-containing polyorganosiloxanes bearing a pendant vinyl group with vinyl monomers. The copolymers thus obtained display increased thermal stability and can be used for the production of laminated plastics, adhesives and other valuable materials 53),... 

Ionomer-type elastomers, containing small amounts (less than 5%) of metal carboxylate or sulfonate groups, have potential as a new class of thermoplastic elastomers. Carboxylic acid groups are introduced into polymers such as polybutadiene by copolymerization with a monomer such as acrylic or methacrylic acid. 

The high electron richness of vinylferrocene as a monomer is illustrated in its copolymerization with maleic anhydride, where 1 1 alternation copolymers are formed over a wide range of monomer feed ratios and ri -2 = 0.003. Subsequently, a large number of detailed copolymerization studies have been undertaken using metal-containing vinyl monomers. 

T he free radical initiated polymerization of polar monomers containing pendant nitrile and carbonyl groups—e.g., acrylonitrile and methyl methacrylate—in the presence of metal halides such as zinc chloride and aluminum chloride, is characterized by increased rates of polymerization (2, 3, 4, 5,10, 30, 31, 32, 33, 34, 53, 55, 65, 66, 75, 76, 77, 87). Imoto and Otsu (30, 33, 34) have attributed this effect to the formation of a complex between the polar group and the metal halide. The enhanced reactivity of the complexed monomer extends to copolymerization with uncomplexed monomers, such as vinylidene chloride, which are readily responsive to... 

In reeent years, methods for synthesizing such catalysts through copolymerization of cluster-containing monomers with common monomers have been elaborated (see Chapter 4). In these cases the exact ratio metal-functional group is determined during the catalyst preparation stage. High activity and selectivity in the action of such catalysts may be expected. 

If a mesogenic monomer is copolymerized with a nonmesogenic monomer, the mesophase is observed above a minimum concentration of the mesogenic monomer. For example, neither poly (methyl meth-acrylate)-co-[6-[4 -(4"-cyanophenylazo)-phenoxy]hexyl methacrylate]) DP 35, pdi =1.35) nor poly (methyl methacry late)-co-[6-[4 -(4"-n-butoxyphenoxycarbonyl)-phenoxy]hexyl methacrylate] DP 69, pdi =1.12) (Scheme 36) prepared by metal-loporphyrin-initiated copolymerizations and containing 18-20 mol% of the mesogenic monomer exhibit the SmA mesophase of the corresponding SCLCPs [90]. 

Cqpolymerization of MCM with traditional monomers is the main technique of metal insertion into a polymer chain, and it is more widely used than their homopolymerization. However, ocpolymerization laws in such systems are difficult to analyze because of their raultiparameter dependence of the kinetics and copolymerization characteristics on the process, parameters such as pH, solvent nature and even concentration ratio (30). The metal-containing giroup in MCM is, as a rule, an electron-donor substituent (scheme Q-e). The copolymerization yields complexes of different comonomers, effecting the polymer composition and structure. In our view, the most remarkable one is cqpolymerization of transition metal diacrylates with MMA, styrene, etc. (37), as well as vinylpyridine and vinylimidazole MX complexes and formation of ternary copolymers of the following composition (38) ... 

Metal-containing polymers are also applied to the catalysis of other processes such as polymerization and copolymerization of butadiene and isoprene (see, e.g., ref. (64)), oopolymerization of diene and olefin monomers and polymerization conversions of acetylene-type monomers (65). Such investigations are likely to be oriented both theoretically and practically. Metallopolymers can be used as advantage in some other catalytic processes (54), among them hydrogenation of imsaturated carpounds, oxidative conversions of hydrocarbons, in hydroformylation, polycondensation and other processes, etc. (Table 4). Catalysis of almost all reactions obeys the same or similar principles as in the case of polymerization. The position of metallopolymers in catalysis and their links with traditional catalysts can be illustrated as follows ... 

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