SYNTHESIS OF NOVEL THIOPHENEDIMETHYLENE BRIDGED HOMOBINUCLEAR METALLOCENES AND THEIR CATALYTIC PROPERTIES FOR ETHYLENE POLYMERIZATION

By treating disodium(thiophenedirnethylene)dicyclopentadienide C_4H_2S(CH_2C_5H_4Na)_2 with two equivalent of CpTiCl_3 or CpZrCl_3 DME at 0℃ in THF,two new thiophenedimethylene bridged binuclear metallocenes [Cl_2MC_5H_5][C_5H_4CH_2C_4H_2SCH_2C_5H_4][C_5H_5MCl_2](M=Ti 3,M=Zr 4)were synthesized in high yield and their structures were characterized by ~1H-NMR.These complexes were used as catalysts for ethylene polymerization in the presence of methylaluminoxane(MAO).The effects of polymerization temperature,time,concentration of catalyst,molar ratio of MAO/Cat on polymerization were studied in detail.The catalytic activities of thiophenedimethylene bridged binuclear metallocene catalysts(3,4)reached 2.44×10~5 g PE mol~(-1)·cat~(-1)·h~(-1),9.61×10~5 g PE mol~(-1)·cat~(-1)·h~(-1) respectively,which are higher than that of pheneyldimethylene bridged binuclear metallocene catalysts and much higher than that of corresponding mononuclear metallocenes(Cp_2TiCl_2 and Cp_2ZrCl_2).The molecular weight distribution curves of polyethylenes produced by binuclear metallocene catalysts(3,4)and by mononuclear metallocene catalyst have only single peak,but the former(MWD=3.5-4.7)is obviously broader than the latter(MWD=2.0-2.2).

Synthesis of Novel Thiophenedimethylene Bridged Homobinuclear Metallocenes and Their Catalytic Properties for Ethylene Polymerization

By treating disodium(thiophenedimethylene)dicyclopentadienide C4H2S(CH2C5H4Na)2 with two equivalent of CpTiCl3 or CpZrCl3 DME at 0℃ in THF, two new thiophenedimethylene bridged binuclear metallocenes [Cl2MC5H5][C5H4CH2C4H2SCH2C5H4][C5H5MCl2] (M = Ti 3, M = Zr 4) were synthesized in high yield and their structures were characterized by 1H-NMR. These complexes were used as catalysts for ethylene polymerization in the presence of methylaluminoxane (MAO). The effects of polymerization temperature, time, concentration of catalyst, molar ratio of MAO/Cat on polymerization were studied in detail. The catalytic activities of thiophenedimethylene bridged binuclear are higher than that of pheneyldimethylene bridged binuclear metallocene catalysts and much higher than that of corresponding mononuclear metallocenes (Cp2TiCl2 and Cp2ZrCl2). The molecular weight distribution curves of polyethylenes produced by binuclear metallocene catalysts (3, 4) and by mononuclear metallocene catalyst have only single peak, but the former (MWD = 3.5-4.7) is obviously broader than the latter (MWD = 2.0-2.2).