Vinyl organometallic monomers

A large number of vinyl organometallic monomers have been prepared, homopolymer-ized, and copolymerized with classic vinyl monomers by Pittman and others. These include polymers containing Mo, W, Fe, Cr (structure 11.33), Ir, Ru, Ti (structure 11.34), Rh (structure 11.35), and Co. 

NEW VINYL ORGANOMETALLIC MONOMERS SYNTHESIS AND POLYMERIZATION BEHAVIOR... 

High-Performance Polymers Aromatic Heterocyclic Monomers Thermally Stable Polymers High-Performance Composites Reactive Oligomers Aromatic Polyformals Star and Comb Shape Copolymers Polymers in Phase Transfer Catalysis Organometallic Polymers Poljmiers in Medical Applications Nitrogen-Containing Polymers Vinyl Organometallic Monomers Functionalized Polymers Anionic Copolymerizations Macromers... 

Liquid-crystalline polysiloxanes containing 1,3- or l,l -disubstituted ferrocene moieties in their sidechains were also synthesized through a reaction of vinyl organometallic monomers with preformed polysiloxanes. " The synthesis of one such liquid-crystalline metal-containing polysiloxane 55 is shown in scheme 17. 

Pittman built on the premise that vinyl organometallic monomers might be styrene-like. Special metal-containing vinyl monomers were developed. Thus, acrylates and methacrylates of ferrocene were prepared and their homo- and copolymerizations... 

Two major approaches to the formation of materials of this type have involved the derivatization of preformed organic polymers with organometallic functions and the synthesis and polymerization of organometallic monomers that contain vinyl substituents For the transition metals, condensation polymerizations have also been investigated. However, the reactions have generally been conducted at elevated temperatures, and the resulting products have often not... 

In this study the relationship between the structure of organometallic compounds and their ability to polymerize vinyl monomers and olefins will be examined. The objective is to identify methods of synthesis for polymerization catalysts that are more selective and more active than the systems currently available. 

The molecular design of stereospecific homogeneous catalysts for polymerization and oligomerization has now reached a practical stage, which is the result of the rapid developments in early transition metal organometallic chemistry in this decade. In fact, Exxon and Dow are already producing polyethylene commercially with the help of metallocene catalysts. Compared to the polymerization of a-olefins, the polymerization of polar vinyl, alkynyl and cyclic monomers seems to be less developed. 

Related organometallic monomers, such as the cyclopentadienylchromium complexes, shown as 6.7 and 6.8, have also been homo- and copolymerized, using free radical initiation.7 Here, too, the transition metal in 6.7 generates an electron-rich vinyl group which deactivates the monomer. 

Kuran, W., Polar Vinyl Monomer Polymerization and Copolymerization with Olefins Promoted by Organometallic Catalysts , Polimery, 42, 604-609 (1997). 

The importance of the electrophilic character of the cation in organo-alkali compounds has been discussed by Morton (793,194) for a variety of reactions. Roha (195) reviewed the polymerization of diolefins with emphasis on the electrophilic metal component of the catalyst. In essence, this review willattempt to treat coordination polymerization with a wide variety of organometallic catalysts in a similar manner irrespective of the initiation and propagation mechanisms. The discussion will be restricted to the polymerization of olefins, vinyl monomers and diolefins, although it is evident that coordinated anionic and cationic mechanisms apply equally well to alkyl metal catalyzed polymerizations of polar monomers such as aldehydes and ketones. 

A number of organometallic polymers containing metallocenes and metallocene analogues has been well-known for some time2. Because of the features of high-temperature stability and radiation resistance of the ferrocene nucleus, ferrocene-containing polymers are of special interest. Basically, these polymers may be divided into two classes the metallocene moiety is either located in a pendant group or in a backbone of the polymer chain. The former polymers have been synthesized by vinyl polymerization of vinyl metallocene monomers such as vinylferrocene. The latter polymers have been prepared by polycondensation of l,l -disubstituted metallocenes or metallocene dihalides with a.w-disubstituted monomers, and fell into two main types, (A) and (B). 

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