Alternating Copolymerizations of Polar and Nonpolar Cyclic Olefins by Ring-Opening Metathesis Polymerization

English (OpenAlex)

The results from copolymerizations of polar 2,3-difunctionalized 7-oxanorbornene derivatives with a series of nonpolar cyclic olefins cyclooctene, cyclooctadiene, cyclopentene, and norbornene using catalysts RuCl 2 ( CHPh)(PCy 3 ) 2 ( 1 ) and its mono-1,3-dimesitylimidazolidine-2-ylidene derivative ( 2 ) are reported. The resulting polymer microstructures have been analyzed by 1 H, 13 C, and 1 H− 1 H COSY NMR spectroscopies. Highly alternating structures were observed for the copolymerizations of endo - N -ethyl-7-oxanorbornene-2,3-dicarboxylimide ( endo - 3 ), exo,exo -7-oxanorbornene-2,3-dimethylester ( exo - 4 ), or exo -7-oxanorbornene-2,3-dicarboxylic anhydride ( exo- 5 ) with cyclooctene using catalyst 1 . The rates of homopolymerizations of endo - 3, exo- 5, and cyclooctene were determined. Comparison with the rate of the copolymerization of endo - 3 with cyclooctene reveals a rate faster than the homopolymerization of endo - 3 but slower than the homopolymerization of cyclooctene. The rate of the copolymerization of exo- 5 with cyclooctene was observed to be greater than the rate of homopolymerization of either monomer. The use of catalyst 2 resulted in lower levels of alternation with a tendency toward random polymerization.