Group 4 complexes derived from o-carborane: synthesis, structures and ethylene polymerization properties

Abstract

Nine thermally stable complexes (eta(5)-CP*)[eta(5)-(C5H4)CMe2CB10H10CR]MCl2 (R=H and Me) and (eta(5)-Cp*)[eta(5); eta(5)- (C5H4)CMe2(CB10H10C)]MCl have been prepared via metathesis reactions Of CP*MCl3 (M = Ti, Zr and Elf, Cp* = pentamethylcyclopentadienyl) with monolithium salts Of (C5H5)CMe2(CB10H10CR) (R=H and Me) and with dilithium salt of (C5H5)CMe2(CB10H10CH), respectively. These compounds have been fully characterized by various spectroscopic methods and elemental analyses. All of the compounds except (eta(5)-Cp*)[eta(5)-(C5H4)CMe2CB10H10CMe]HfCl2 were additionally characterized by a single crystal X-ray diffraction study, establishing their monomeric bent metallocene structural feature with carborane acting as a substituent or an ancillary ligand. The titanium and zirconium complexes produce high-density polyethylenes with the activity range of about 10(3)-10(4) g PE per mol of M bar h in the presence of modified methylaluminoxane cocatalyst. (C) 2003 Elsevier Science B.V. All rights reserved.