OLEFIN POLYMERIZATION BY (CYCLOPENTADIENYL)(ARYLOXY)TITANIUM(IV) COMPLEXES-COCATALYST SYSTEMS

Various titanium(IV) complexes of the type Cp'Ti(OAr)Cl-2 (Cp' = cyclo pentadienyl; OAr = aryloxy) could be prepared in high yields from Cp'T iCl3. CpTi(O-2,6-(Pr2C6H3)-Pr-i)Me-2 (Cp* = C5Me5) could also be prep ared from CpTiMe3 with 2,6-(Pr2C6H3OH)-Pr-i in high yield(77%). These complexes showed notable catalytic activities for ethylene polymeriza tion with MAO or (AlBu3)-Bu-i-Ph3CB(C6F5)(4): CpTi(O-2,6-(Pr2C6H3)-Pr -i)X-2 [X= Cl (2b), Me (8b), CF3SO3 (9b)] showed the highest activitie s among these complexes. The effects of substituents on both cyclopent adienyl (pentamethylcyclopentadienyl) and aryloxy (2,6-diisopropylphen oxy) groups are important for the remarkable activity. The crystallogr aphic analyses of CpTi(O-2,6-(Pr2C6H3)-Pr-i)Cl-2 (Ib), CpTi(O-2,6-(Pr 2C6H3)-Pr-i)Cl-2 (2b), and (1,3-(Bu2C5H3)-Bu-t)Ti(O-2,6-(Pr2C6H3)-Pr-i )Cl-2 (6b) could be performed, and the bond angle of Ti-O-C (phenyl gr oup) for 2b (173.0 degrees) was found to be significantly different fr om those for other complexes (162.3-163.1 degrees), although no signif icant differences are observed for other bond lengths and angles among these compounds. CpTi(O-2,4,6-Me3C6H2)(2)Cl (7a) and CpTi(O-2,6-(Pr2C 6H3)-Pr-i)(2)Cl (7b) could be prepared from CpTiCl3 with the correspon ding phenol under the refluxing conditions of toluene, and the structu re of 7a could be determined by X-ray crystallography. These complexes also exhibited moderate catalytic activities for ethylene polymerizat ion in the presence of MAO, which was prepared by removing toluene and an excess amount of AlMe3, and the effect of the bulk of phenoxy liga nd on the activity was demonstrated. 2b was also found to be an effect ive catalyst precursor for ethylene/1-butene copolymerization, and the smaller r(E)r(B) values (0.25-0.36) compared to [Me2Si(C5Me4)((NBu)-B u-t)]TiCl2 (2.45) were observed by microanalysis of the resultant copo lymers.