摘要
Three mono-cyclopentadienyl metal complexes, [C_6H_4O_2]CpTiCl (Ⅰ),[C_(12)H_8O_2]CpTiCl (Ⅱ), and [C_(20)H_(12)O_2] CpTiCl (Ⅲ), were prepared via the reactions ofcyclopentadienyl titanium trichloride with catechol, 2,2i-bisphenol, and 2,2'-bisnaphthol,respectively. In the presence of a moderate amount of methylaluminoxane (MAO), the complexesexhibited catalytic activities for ethylene polymerization. Complex Ⅰ showed the highest activityat Al/Ti molar ratio of 500 at the temperature of 30℃. With increasing of polymerizationtemperature, catalytic activities and molecular weight of the obtained polyethylene tended todecrease, and molecular weight distribution of polyethylene became narrower. With the molecularsimulation method, the charges on titanium atoms of complexes Ⅰ, Ⅱ, and Ⅲ, and the bond anglesformed by Ti and bisphenoxy ligands were calculated. It was concluded that the smaller the netcharge on Ti and the smaller the angle of O1―Ti―O2, the higher the activity of the complex.
Threemono-cyclopentadienyl metal complexes, [C6H4O2]CpTiCl (Ⅰ), [C12H8O2]CpTiCl (Ⅱ), and [C20H12O2]and 2,2'-bisnaphthol, respectively. In the presence of a moderate amount of methylaluminoxane (MAO), thecomplexes exhibited catalytic activities for ethylene polymerization. Complex I showed the highest activity atAl/Ti molar ratio of 500 at the temperature of 30 ℃. With increasing of polymerization temperature, catalyticactivities and molecular weight of the obtained polyethylene tended to decrease, and molecular weight distri-bution of polyethylene became narrower. With the molecular simulation method, the charges on titanium atomsof complexes Ⅰ, Ⅱ, and Ⅲ, and the bond angles formed by Ti and bisphenoxy ligands were calculated. It wasconcluded that the smaller the net charge on Ti and the smaller the angle of O 1-Ti-32, the higher the activity of the complex.
基金
The work is supported by Special Funds for State Major Basic Research Projects of China(No.G1999064801)
