ROMP polymers

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. 

Figure 4.6 Phosphoramidite coupling onto hydroxyl-functionalized ROMP polymers (Watson et al. 2001).

ROMP polymers bearing acid chloride, phosphonate, carbodiimide, phosphonyl chloride, and phosphine groups have been used as platforms in phase-switching, sequestration, capture-release, and soluble support applications. 

Future industrial prospects are suggested by the exceptionally diverse range of applications in which ROMP polymers have now been deployed. The impact of ROMPgel reagents was alluded to above. These and... 

Although a polymer prepared by this method has improved oxidative stability, the thermal stability is reduced. In general, hydrogenation increases the glass transition temperature of a ROMP polymer by about 50°C, but because of the ethylene groups located... 

For the 9-fluorenylmethoxycarbonyl (Fmoc) protection of amino acids, Chinchilla et al.36,37 prepared a similar ROMP-polymer that supports an activated. V-hydroxysuccinimide Fmoc-carbonate (Table VII, entry 31). Various Fmoc-amino acids are prepared in pure form after removal of the polymer reagent by filtration and aqueous phase separation. 

Research over the past 30 years has produced a large number of ROMP polymers, and virtually all of these polymerizations have been reviewed elsewhere. The most recent work has revolved about the living or pseudoliving nature of ROMP polymerization, and a few words regarding this chemistry are worth mentioning here. 

Figure 13 ROMP polymers of defined length. Varying the ratio of monomer (14) to catalyst (15) affords control over the average polymer 16 length ( ).

Scheme 6.11 Horner-Wadsworth-Emmons reactions using a phosphonate attached to a ROMP-polymer.

Kiessling has pioneered the use of ROMP polymers to explore a variety of protein-saccharide interactions that are critical components of diverse biological processes [59]. 

Polymers for use in 193 nm lithography are co-, ter-, and tetra-polymers of 1) methacrylates, 2) norbornenes, 3) norbornene-maleic anhydride, 4) nor-bornene-sulfur dioxide, and 5) vinyl ether-maleic anhydride (Fig. 39). While 1), 3), 4), and 5) are prepared by radical polymerization, all-norbornene polymers 2) are synthesized by transition-metal-mediated addition polymerization [166-168].Norbornenes (Fig.40) are sluggish to undergo radical [168,169] and cationic [170] polymerizations. Their ring-opening metathesis polymerization (ROMP, Fig. 40) [ 171 ] has never produced worthy resist polymers. The C=C double bonds introduced in the ROMP polymer backbone must be hydrogenated to reduce the 193 nm absorption and the ROMP polymers tend to have low Tg. However, the major problem for the ROMP polymers was their unacceptable swelling in aqueous base development. While polymethacrylate systems contain etch-resistant alicyclic structures in the ester side chain, norbornene-based systems carry the alicyclic unit in the backbone. Essentially all the 193 nm re-... 

One of the first applications of ROMP polymers such as poly(7-oxanorbomene)-2,3-dicarboxylic acids... 

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