Synthesis of half-metallocene complexes ([O

N]CpTiCl2) containing 8-hydroxy-quinoline ligand is described. The results indicate that [O

N]CpTiCl2 is active for ethylene polymerization at 30℃ and 0.1 mPa with MAO activation

and exhibits much higher activity than CpTiCl3．The results show that when there is an electrondonor substituent next to N

such as a methyl

the activity of [O

N]CpTiCl2 increases greatly；however

if there is an electron-acceptor substituent

such as nitro in the benzene ring

it is inactive．For the [O

N]CpTiCl2／MAO system

the polymerization rate is “up and down” type with increasing the Al／Ti molar ratio．The activity reaches its maximum at molar ratio of Al／Ti=500

which is over 1×105 gPE/molTi·h．The activity decreases as the polymerization time is longer．The polyethylene obtained is characteristic of narrow molecular distribution with molecular weight Mw around 40×104 and molecular weight ratio Mw／Mn=2.8．