Synthesis of mono- and bis- benzimidazolin-2-iminato titanium complexes and their catalytic performances in ethylene homo- and co- polymerizations

Abstract A series of mono- and bis- benzimidazolin-2-iminato titanium complexes (Ti1–Ti6) were synthesized herein. All the complexes were isolated in high yields and confirmed by 1H and 13C NMR spectra. Molecular structures of complexes Ti1, Ti3, and Ti4 were further determined by single-crystal X-ray diffraction, which gave comprehensive bond properties as well as structural differences with the previously reported imidazolin-2-iminato titanium analogs. Being activated by methylaluminoxane (MAO), all the complexes showed moderate activities for ethylene homopolymerization and copolymerization with α-olefins. In all the cases, the resultant polymers had narrow molecular weight distributions. The catalysts still possessed acceptable polymerization activities even at a temperature of 90 °C, implying the uniqueness of the benzimidazolin-2-iminato ligand.