Norbomenes homopolymerization

Here, we report norbomene-ethylene copolymerization in the presence of specific nickel catalysts. Furthermore, we present some unpublished results concerning norbomene homopolymerization. 

Late transition metal catalysts, which are more tolerant of polar functional groups than early transition metal catalysts, are most suitable and highly active for norbomene homopolymerizations or copolymerization with other cycloolefins. A range of tailor-made homo-, co-, and terpolymers based on substituted norbomenes for applications in electronic materials are produced and commercialized, but they need further development to be efficiently used in olefin-cycloolefin copolymerizations. 

The resulting complexes can be effectively employed as single component catalysts to homopolymerize ethylene or copolymerize ethylene with acrylates [50, 51] and a variety of other polar monomers including vinyl ethers, [51,52] vinyl fluoride [53], iV-vinyl-2-pyrrolidinone, and AMsopropylacrylamide [54], In fact, the resulting catalysts are so robust that they can be used as single component catalysts in aqueous emulsion homo-polymerization of ethylene and copolymerization of ethylene with norbomenes and acylates [55]. 

For 5- or 5,6-substituted norbomenes the exo-isomer is usually rather more reactive than the ewrfo-isomer. An extreme case is provided by the exo- and mfo-isomers of 190 where the exo-isomer polymerizes first, followed much more slowly by the endo-isomer see Section Vm.C.12. In other cases the endo-isomer will not polymerize but will copolymerize to some extent with its exo-isomer, as with the isomers of 197531. Other examples of this kind, where M2 will not homopolymerize using a particular catalyst, are the copolymerization of norbomene (Mi), (i) with cyclopentene (M2), catalysed by Ru(OTs)2(OH2)6597, (ii) with 192, catalysed by WClg/Me4Sn526 and (iii) with cyclohexene (M2), catalysed by WCl6/Me4Sn358,359. 

Metallocene-based Ziegler-Natta catalysts are capable of polymerizing cyclic monomers without ringopening reactions that are characteristic of heterogeneous Ziegler-Natta catalysts. Kaminsky reported the homopolymerization of cyclic monomers such as cyclobutene, cyclopentene, norbomene, and dimetha-nooctahydronaphthalene (Scheme 22) with MAO-activated zirconocene catalysts. Cyclobutene was approximately 5 times more reactive than cyclopentene, which was more reactive than norbomene. ... 

Half-sandwich complexes of titanium, when activated by a cocatalyst such as MAO, are even more active for the homopolymerization of norbomene than metallocenes. Heitz and Peucker found that chromium-based half-sandwich complexes can also be activated to produce PNBs and E/NB copolymers. Nevertheless, detailed investigations on half-sandwich complexes for the addition polymerization of norbomene do not appear in the literature. 

Myagmarsuren G, Lee Ki-Soo, Jeong O-Yong, Ihm Son-Ki (2005) Homopolymerization of 5-alkyl-2-norbornenes and their copolymerization with norbomene over novel Pd(acac)2/PPh3/Bp30Et2 catalyst system. Polymer 46 3685-3692... 

Diamanti, S.J., Ghosh, P, Shimizu, E., and Bazan, G.C. (2003) Ethylene homopolymerization and copolymerization with functionalized 5-norbomen-2-yl monomers by a novel nickel catalyst system. Macromolecules, 36,9731-9735. 

Electrochemically active materials can be accessed as metals and ions are well tolerated. For example, the homopolymerization of a norbomene monomer modified to include ferrocene linked through an alkyl qrratemary ammonirrm salt affords... 

A benefit of functionalized homopolymers is the ability to perform postpolymerization modifications. A norbomene bearing a methacroyl isocyanate efficiently underwent homopolymerization via ROMP to yield a cross-linked homopolymer, which upon ligand exchange with poly(methyl methacrylate) afforded a material with enhanced thermal stability over the original poly(methyl methacrylate). The preparation of an oxanorbomene derivative bearing a 1,2-bis (3-thienyl)cyclopentene photochrome followed by ROMP accessed a polymer capable of the same reversible photoisomerization as the monomer. 

A number of conjugated ferrocene-based polymers have been synthesized via ROMP of ferrocenophanes that possess bridging olefinic units.Buretea and Tilley reported the homopolymerization of ansa-vinyleneferrocene and its copolymerization with norbomene. While the homopolymers were insoluble materials that had a conductivity of 10 0 cm , the copolymer had and values of 21,000 and... 

The f22 values are in general lower than those obtained for propene or other a-olefms, in agreement with the low homopolymerization activity of norbomene. The f22 value for catalyst 1-5 is much greater than ri2 this shows the tendency of this catalyst to insert a third norbomene after the second one. It was clear that the next-to-last E or norbomene monomer unit exerts an influence on the reactivity of the propagating Mt-E or Mt-N species, which depends upon the catalyst stmc-ture. The second-order Markov model must be used to describe E-N copolymerizations promoted by metallocenes I-l, 1-2, and IV-1. A third-order or a more complex model may be required to fit the experimental data obtained with catalyst 1-6, where more sterically hindered indene substitutions are dominant. At higher norbomene concentrations, copolymers with all catalysts may need more complex models. These results allowed the conclusion that E-N copolymerization is dominated by the bulkiness of the norbomene monomer and of the copolymer chain. 

Homopolymerization of monomer 2 (Scheme 3) was carried out by using 2" generation Grubbs catalyst at room temperature in dry CDCljUnd CD3OD (9 1 v/v %) solvent system and monitored by HNMR. New peaks were observed at 5 5-5.3 ppm, and norbomene olefmic protons were disappeared at 5 6.6 ppm indicating the formation of the product. The stretching... 

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