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Polymerization functionalized norbornene

A carbazole-functionalized norbornene derivative, 5-CN-carbazoyl methy-lene)-2-norbornene, CbzNB, was polymerized via ROMP using the ruthenium catalyst Cl2Ru(CHPh)[P(C6Hii)3]2 [100]. The polymerization was conducted in CH2C12 at room temperature, to afford products with polydispersity indices close to 1.3. Subsequent addition of 5-[(trimethylsiloxy)methylene]-2-norbornene showed a clear shift of the SEC trace of the initial polymer, indicating that a diblock copolymer was efficiently prepared in high yield. [Pg.54]

The first documented example of the living ROMP of a cycloolefin was the polymerization of norbornene using titanacyclobutane complexes such as (207) 510-512 Subsequent studies described the synthesis of di- and tri-block copolymers of norbornenes and dicyclopentadiene.513 However, functionalized monomers are generally incompatible with the highly electrophilic d° metal center. [Pg.29]

The earliest reported ring-opening polymerizations of functionalized norbornenes were carried out in protic solvents (alcohol, water) using iridium, ruthenium, or osmium salts. Thus, norbornenes substituted with ester (93-95), hydroxy (95), chlorine (96), alkoxy (97), and imide (93) groups have been polymerized via metathesis using noble metal catalysts. [Pg.486]

The first report of ROMP activity by a well-characterized Mo or W species was polymerization of norbornene initiated by W(CH-t-Bu)(NAr)(0-f-Bu)2 [122]. In the studies that followed, functionality tolerance, the synthesis of block copolymers, and ring-opening of other monomers were explored [30, 123]. Two important issues in ROMP concern the cis or trans nature of the double bond formed in the polymer and the polymer s tacticity. Tacticity is a consequence of the presence of two asymmetric carbons with opposite configuration in each monomer unit. The four ROMP polymers (using polynorbornene as an example) that have a regular structure are shown in Scheme 3. [Pg.26]

The living character of the ring opening metathesis polymerization described earlier in this review enables a simple preparation of functionalized norbornene-based monoliths. Adding one more in situ derivatization step that involves functional norborn-2-ene and 7-oxanorborn-2-ene monomers that react with the surface-bound initiator, the pores were provided with a number of typical functional groups such as carboxylic acid, tertiary amine, and cyclodextrin [58,59]. [Pg.98]

Functionalized norbornenes are mostly modified in the 5-posi-tion. Substituents with ester groups or other donor groups, may slow down the rate of polymerization as they form chain propa-... [Pg.41]

Chloromethyl polystyrene can be converted to a free-radical initiator by reaction with 2,2,6,6-tetramethylpipcridinc-/V-oxyl (TEMPO). Radical polymerization of various substituted alkenes on this resin has been used to prepare new types of polystyrene-based supports [123]. Alternatively, cross-linked vinyl polystyrene can be copolymerized with functionalized norbornene derivatives by ruthenium-mediated ringopening metathesis polymerization [124],... [Pg.25]

A final illustration of the effect of coordinating functionalities on the polymerization of olefins by cationic metal complexes involves norbornene derivatives. The species, [Pd(PR3)(Me)]+, generated in situ by halide abstraction from [Pd(PR3)(Me)(Cl)]2, is an extremely active catalyst for the insertion polymerization of norbornene with a rate exceeding of 1000 tons norbornene/mol Pd hour at... [Pg.309]

Because they are synthesized by Diels-Alder reaction, functionalized norbornene derivatives sold commercially consist of exo and endo isomers with the latter predominating. The drop in polymerization rate for functionalized norbornene derivatives may be ascribed to the formation of a chelate by coordination of the metal to the functionality and the C = C bond along the endo face (see Fig. 9.2). [Pg.310]

This has two detrimental effects on polymerization. First, chelation strengthens the metal-olefin interaction, thereby raising the barrier for the insertion step. Second, it forces insertion through the endo face, in sharp contrast to the known propensity for norbornene to insert into metal-carbon bonds through the less hindered exo face [3 a, 5]. Consistent with this hypothesis has been our observation of the preferential uptake of the exo isomer in the polymerization of functional norbornene derivatives by Pd(PRj)(Me). For example. Fig. 9.3 shows the uptake profile versus time for the polymerization of 5-norbornene-2-carboxyhc acid ethyl ester starting with a monomer isomer ratio of 22% exo to 78% endo. Indeed, under certain conditions a polymer can be obtained from the exo isomer but not the endo isomer [10]. [Pg.311]

Polymer 149, prepared by ring-opening polymerization (ROMP) of the corresponding functionalized norbornene, provides a clear illustration of the potential of this kind of materials. This resin catalyzes (12% molar) the reaction of linear aliphatic aldehydes with unsaturated ketones to provide 1,4-dicarbonyl compounds (153, Scheme 10.23) and was used for four consecutive cycles without any detectable decrease in performance [358]. A similar dimethylthiazolium structure supported on 2% cross-linked PS-DVB (150) was studied as catalyst for the acyloin condensation of a large variety of aldehydes [364], Catalyst 150 is used in 10 mol.% and the reaction takes place in ethanol at room temperature, with triethylamine as the base, to afford the corresponding a-hydroxyketones in excellent yields. Remarkably, the catalyst can be reused 20 times without losing its activity. [Pg.294]

Ring-opening metathesis polymerization was also used recently for the preparation of amphiphilic star-block copolymers [25]. Mo (CH-f-Bu) (NAr) (0-f-Bu)2 was used as the initiator for sequential polymerization of norbornene-type, unfunctionalized and functionalized, monomers. The living diblocks were reacted with endo-ris-endo-hexacyclo- [ 10.2.1.1.3/115>8.02>l 1. O 1-9] heptadeca-6,13-diene, a difunctional monomer in a scheme analogous to the use of DVB in anionic polymerization, to form the central core of the star (Scheme 10). [Pg.13]

Cationic and radical polymerizations of norbornene yield only low molecular weight oligomers [169,170]. Ring-opening metathesis polymerization (ROMP) of strained cyclic olefins was first reported in the 1950s [171] and is of industrial importance. Attempts were made to prepare 193 nm resist polymer by ROMP of functionalized norbornenes and tetracyclododecenes (Fig. 75) [168,251]. Hydrogenation of the unsaturated backbone was necessary to afford ther-mooxidative stability and to reduce OD at 193 nm. Use of tetracyclododecene... [Pg.114]

J.P Mathew, A. Reinmuth, J. Melia, N. Swords, and W. Risse, (ti AUyl)palladium(II) and palla dium(II) nitrile catalysts for the addition polymerization of norbornene derivatives with functional groups, Macromol. 29, 2755 (1996) W. Risse and S. Breunig, Transition metal catalyzed vinyl addition polymerizations of norbornene derivatives with ester groups, Makromol. Chem. 193, 2915 (1992). [Pg.368]

Until now, a large variety of functional norbornenes, norbornadienes, and other cyclic olefins has been polymerized by different transition-metal alkyl-idenes. For convenience, a summary of the... [Pg.136]

NHC)-Pd complexes and their uses in organic syntheses, ranging from C-C coupling to olefin polymerizations [88]. In this work, different (NHC)-Pd complexes active for co/polymerization of acyclic as well as cychc monomers were discussed, with particular interest in functionalized norbornene polymerizations. [Pg.128]

RuCls hydrate is known to be a metathesis initiator since many years [170-172] and it is used in combination with HCl in butanol for the polymerization of norbornene in industrial scale (see Section VII) [81]. Its advantage is the tolerance towards functional groups, however, the induction periods are long and only a small amount of the employed Ru becomes catalytically active [100,171]. [Pg.399]

In addition, classical catalysts, e.g.. Mo- and W-based systems can also polymerize the OCOR functionalized norbornenes [22,446]. Monomers containing 5- and 6-substituents and bearing a OCOR-group have also been prepared and polymerized [23,123,438]. [Pg.418]

The endo-COOMQ functionalized norbornene can also be polymerized with the same catalyst [153]. [Pg.419]

Hydroxy functionalized norbornenes have been polymerized by ring-opening metathesis polymerization using various catalysts. Some selected compounds which undergo ROMP are listed in Table 19. [Pg.420]


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See also in sourсe #XX -- [ Pg.104 ]




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