Synthesis and polymerization behavior of novel C1 and Cs titanium ansa-cyclopentadienyl-amido catalysts for ethylene and propylene polymerization

Abstract

Four titanium ansa-cyclopentadienyl-amido complexes of the general formula [C5H3RMe2SiN (2,6-Me2C6H3)]TiX2(R = H,Me,Bz,tBu;X = NMe2 or Cl) have been synthesized. The complexes polymerize both ethylene and propylene in the presence of methylaluminoxane or Ph3CB(C6F5)4-triisobutyl-aluminum and were most active at lower temperatures. In general, the smaller the substituent on the cyclopentadienyl group, the more active the catalyst. The catalysts were found to be poorly stereoselective for the polymerization of polypropylene, with the tertiary-butyl substituted catalyst giving a polymer with the greatest [mmmm] (14.2%). The structure of [C5H4Me2SiN (2,6-Me2C6H3)] Ti(NMe2)2 was determined by X-ray diffraction. The complex crystallizes in the monoclinic system space group P21/n, with a = 16.437(2), b = 8.652(3), c = 16.494(4), β = 117.54(2) and Z = 4. Copyright © 2002 John Wiley & Sons, Ltd.