Half-titanocene 5-t-butyl-2-(1-(arylimino)methyl)quinolin-8-olate chlorides: Synthesis, characterization and ethylene (co-)polymerization behavior

•Newly synthesized half-titanocene 5-t-butyl-2-(1-(arylimino)methyl)quinolin-8-olate chlorides.•Catalytic systems formed by activated with either MAO or MMAO.•Good activity for ethylene polymerization.•Good activity for the co-polymerization of ethylene with 1-hexene or 1-octene.•Unimodel polyethylenes with high molecular weights.

A series of half-titanocene chloride complexes bearing 5-t-butyl-2-(1-(arylimino)methyl)quinolin-8-olate ligands (L), CpTiLCl2, has been synthesized in acceptable yields by the stoichiometric reaction of CpTiCl3 with the respective potassium 5-t-butyl-2-(1-(arylimino)methyl)quinolin-8-olate. All half-titanocene complexes were fully characterized by elemental analysis and NMR spectroscopy, and the molecular structures of the representative complexes C1 and C2 were confirmed as pseudo octahedral at titanium by single-crystal X-ray diffraction. When activated with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all titanium complexes exhibited good activities (up to 4.8 × 105 g mol−1(Ti) h−1) towards ethylene polymerization. The obtained polyethylene exhibited ultra-high molecular weight (up to 11.82 × 105 g mol−1) with narrow polydispersity. Furthermore, effective co-polymerization of ethylene with 1-hexene or 1-octene was achieved with several percentages of co-monomer incorporation in the resultant polyethylenes.

Graphical abstractA series of half-titanocene 5-t-butyl-2-(1-(arylimino)methyl)quinolin-8-olates chlorides was synthesized and well characterized. When activated with MAO or MMAO, all titanium complexes exhibited good activities towards (co-)polymerization of ethylene and produced polyethylenes with high molecular weight.Figure optionsDownload full-size imageDownload as PowerPoint slide