Vanadium (V) and titanium (IV) compounds with 2-[hydroxy (diaryl)methyl]-8-hydroxyquinolines: Synthesis, structure and catalytic behaviors to olefin polymerization

A series of oxovanadium (V) and titanium (IV) complexes stabilized by [ONO](2-) type ligands-2-[hydroxy(diaryl)methyl]-8-hydroxyquinolines (2-3) were synthesized in high yields and characterized by elemental analysis, NMR-, IR spectroscopy and mass spectrometry. The molecular structures of the representative complexes 4 and 7 were confirmed by single-crystal X-ray diffraction, and revealed distorted octahedral geometry at Ti and tetragonal pyramid in V complex. Titanium-based catalytic systems were found to be active in the ethylene and 1-hexene polymerization and copolymerization, but only in the presence of a binary co-catalyst Et2AlCl/Bu2Mg. Vanadium-based systems were active in the same reactions in the presence of Et3Al2Cl3 or Et2AlCl mixed with CCl3CO2Et reactivator. The amount of co-monomer incorporated by these systems have reached 23 mol%. When applied in the presence of aliphatic solvents vanadium complexes catalyze 1-hexene oligomerization yielding dimers and trimers. When the same process is carried out in toluene, the solvent got alkylated by monomers and light oligomers (Friedel-Crafts reaction). (C) 2016 Elsevier Ltd. All rights reserved.