Group 4 metal alkoxide complexes as catalysts for olefin polymerization

Abstract

The complexation of 3-tert-butyl-2-hydroxy-5-methylbenzaldehyde I with titanium or zirconium tetrachloride yielded two classes of complexes containing either one or two didentate alkoxide ligands. The structures of three monomeric, six-co-ordinate complexes, cis-dichlorobis(3-tert-butyl-5-methyl-2-oxobenzoyl)titanium(IV)1, cis-dichlorobis(3-tert-butyl-5-methyl-2-oxobenzoyl)zirconium(IV)2 and mer-trichloro(3-tert-butyl-5-methyl-2-oxobenzoyl)(tetrahydrofuran)zirconium(IV)3 were characterized by single-crystal X-ray diffraction. Compounds I and 3 crystallize in the monoclinic space group P21 with Z= 2, compound 1 in Cc with Z= 4 and compound 2 in orthorhombic space group Pbca with Z= 8. In the presence of methylaluminooxane complexes 1–3 give homogeneous catalysts, which for the polymerization of ethylene produced high molecular weight polyethylene with a broad molecular weight distribution.