Novel titanium(IV) complexes stabilized by 2-hydroxybenzyl alcohol derivatives as catalysts for UHMWPE production

Abstract A series of titanium (IV) complexes ( 2, 5-7 ) stabilized by a substituted 2-hydroxybenzyl alcohols ( 1, 4 ) – were synthesized. Structures of complexes 6-7 were determined by X-ray diffraction. Titanium atom in the tetrameric complex 6 has an octahedral environment created by chlorine atom and five oxygen atoms. The main structural feature of 7 is a centrosymmetric Ti 4 O 6 cage which is built of two seco-norcubanes Ti 4 O 3 sharing a common Ti 2 O 2 -face. A coordination polyhedron around the titanium atoms is the distorted octahedron, with the long Ti─μ-O and short Ti─O bonds. All resulting complexes are moderately or highly active in ethylene polymerization in the presence of {3Et 2 AlCl + Bu 2 Mg} binary co-catalyst. Resulting polymers are linear ultrahigh molecular weight polyethylenes (up to 7.9 10 6  g/mole). Polymers are suitable for the modern processing methods – the solvent-free solid state formation of super high-strength (tensile strength over 2.0–2.4 GPa) and high-modulus (elastic modulus up to 130 GPa) oriented film tapes.