Synthesis, characterization, and catalytic activities in syndiospecific polymerization of styrene for half-sandwich titanium complexes with non-Cp tridentate dianionic ligands MeN(CH2CR2O−)2
摘要:
New half-titanocenes, Cp*TiCl[(OCR(2)CH(2))NMe(CH(2)CR(2)' O)] [R,R ' = H (1), R,R ' = Me, H, (2), R,R ' = Me (3)], were prepared from Cp*TiCl(3) (4) with the corresponding alcohols in the presence of triethylamine. X-ray analysis shows that 1 has slightly distorted trigonal bipyramidal geometry around Ti. These complexes exhibited moderate catalytic activities for syndiospecific styrene polymerization in the presence of MAO and the activity increased in the order: 2 > 1 > 4 > 3 (at 50 degrees C), 1 > 2 > 4 > 3 (at 70 degrees C and 90 degrees C). (C) 2008 Elsevier B.V. All rights reserved.
New half-sandwich metallocene catalysts for polyethylene and polystyrene
作者:Youngjo Kim、Yonggyu Han、Youngkyu Do
DOI:10.1016/s0022-328x(01)01105-6
日期:2001.9
A new type of half-sandwich metallocene catalysts for the polymerization of ethylene and styrene, Cp*MCl(DEA-R) (DEA = (OCH2CH2)(2)N, R = Me, M = Ti (1); R = Me M = Zr (2); R = n-Bu, M = Ti (3)), was prepared by the reaction of corresponding N-alkyl-N,N-diethanolamine with Cp*MCl3 in the presence of triethylamine. Compounds 1-3 are slightly air-sensitive and thermally unstable. All catalyst systems show moderate activities in ethylene polymerization and especially the 2/MMAO system gives PE with broad molecular weight distribution at all polymerization temperatures. In addition, 1/MMAO and 3/MMAO show fairly good activities in sPS polymerization in the order 3/MMAO > 1/MMAO. (C) 2001 Elsevier Science B.V. All rights reserved.