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Copolymerization of ethylene (E) with 2-methyl-1-pentene (2M1P) took place with rather efficient 2M1P incorporation by using the Cp*TiCl2(O-2,6- i Pr2C6H3) (1)−MAO catalyst system, whereas the 2M1P incorporations by the Cp2ZrCl2, [Me2Si(C5Me4)(N t Bu)]TiCl2, Cp‘TiCl2(NC t Bu2) [Cp‘ = Cp (3), Cp* (4)], and Cp*TiCl3−MAO catalyst systems were negligible under the same conditions. The effects of substituents in both the cyclopentadienyl and the aryloxide ligands toward the catalytic activities and the 2M1P incorporations were explored, and use of both Cp* and 2,6-diisopropylphenoxy ligands was found to be important to obtain poly(ethylene-co-2M1P)s with rather efficient and uniform 2M1P incorporations as well as with notable catalytic activities. No distinct differences in the 2M1P incorporations were seen in the copolymerization by 1 in the presence of various cocatalysts [methylaluminoxane (MAO), methylisobutylaluminoxanes (MMAOs), borates], and the nature of ligands directly affects the 2M1P incorporation. Copolymerizations of ethylene with 7-methyl-1,6-octadiene (MOD) by 1,3,4−MAO catalyst systems proceeded at remarkable rates with efficient exclusive incorporation of monoolefins (without incorporating trisubstituted olefin), affording high molecular weight unsaturated poly(ethylene-co-MOD)s with high MOD contents. The MOD contents in the resultant copolymers in the ethylene/MOD copolymerization by 1,3,4−MAO catalyst systems were thus closely related to those in the ethylene/1-octene copolymerizations under similar conditions.

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Copolymerizations of ethylene with vinylcyclohexene (VCHen) by using Cp′TiCl2(X) [X = O-2,6- i Pr2C6H3, Cp′ = Cp* (1); X = NC t Bu2, Cp′ = Cp* (2) and Cp (3)] catalyst systems with MAO have been explored. The copolymerizations proceeded via vinyl addition/insertion affording high molecular weight copolymers containing cyclohexenyl side chains (with uniform compositions as well as with unimodal molecular weight distributions) accompanied with certain degree of side reaction (intramolecular cyclization after VCHen insertion). Degree of the side reaction (cyclization) was dependent upon the catalyst employed, polymerization temperature, but was not affected by the time course, the Al/Ti molar ratios. The Cp−ketimide analogue (3) showed the best catalyst performance in terms of both the catalytic activity and the selectivity (lowest degree of the subsequent intramolecular cyclization) in the copolymerization. Quantitative epoxidation of the olefinic double bonds in the resultant copolymer has been achieved by using m-chloroperbenzoic acid under mild conditions; a facile, precise synthesis of functionalized polyolefin has thus been demonstrated by adopting this approach.