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

Abstract 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 Et 2 AlCl/Bu 2 Mg. Vanadium-based systems were active in the same reactions in the presence of Et 3 Al 2 Cl 3 or Et 2 AlCl mixed with CCl 3 CO 2 Et 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).