| Abstract
| - Cp*TiCl2[N(Me)R1] [R1 = Me (1), Et (2), Cy (3), Cp* = C5Me5, Cy = cyclohexyl], and (1,3-Me2C5H3)TiCl2[N(Cy)R2] [R2 = Me (4), Cy (5)] have been prepared from the reaction of Cp‘TiCl3 (Cp‘ =cyclopentadienyl) with the corresponding lithium amide in toluene or n-hexane. The structures for 3, 4,and 5 have been determined by X-ray crystallography. The catalytic activity for ethylene polymerizationin the presence of d-MAO [prepared by removing toluene and AlMe3 from ordinary methylaluminoxane(MAO) solution] increased in the order: 3 (4540 kg-PE/mol-Ti·h, in toluene, ethylene 6 atm, 25 °C, 10min) ≫ 5 (2000 kg-PE/mol-Ti·h) > 2 (1680), 1 (1600), and 4 (1520). In particular, 3 exhibited the highestcatalytic activity, suggesting both electronic and steric factors play a role. On the other hand, 4 exhibitedthe highest catalytic activity for syndiospecific styrene polymerization, and the results clearly show thatefficient catalyst for the desired polymerization can be modified only by replacing the substituent on Cp‘.3 exhibited better 1-hexene incorporation than 1, affording poly(ethylene-co-1-hexene) with high molecularweight. 4 exhibited both the highest catalytic activity and efficient 1-hexene incorporation, and the1-hexene incorporation as well as the monomer sequence distributions were affected by the substituentson both cyclopentadienyl and amide ligands. On the other hand, Cp*TiCl2[N(2,6-Me2C6H3)(SiMe3)] (6)showed poor 1-hexene incorporation under the same conditions, affording the copolymer with relativelylow molecular weight. The resultant rErH values by 3 and 4 were 0.38−0.48, which showed that thesecopolymerizations did not proceed in a random manner that can be seen in ordinary metallocene andlinked half-metallocene catalysts.
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