1-Hexene Homopolymerization and Copolymerization with Polar ω-Halo-α-alkenes by (Benz)imidazolin-2-iminato Scandium and Yttrium Complexes
Wenpeng Zhao, Beibei Wang, Bo Dong, Heng Liu, Yanming Hu, Moris S. Eisen, Xuequan Zhang
Abstract
The synthesis and characterization of (benz)imidazolin-2-iminato scandium and yttrium complexes (Sc1–Sc3, Y1, and Y2) are reported herein. All of the complexes were isolated in high yields, and from single-crystal X-ray diffraction analysis, extremely short N–Mt bonds were revealed, indicating the highly nucleophilic nature of the ligands. In the presence of [Ph3C][B(C6F5)4] and Al(i-Bu)3, scandium complexes showed medium to high activities for 1-hexene polymerization, revealing the trend Sc1 > Sc3 > Sc2. More importantly, the scandium complex Sc1 was active in the copolymerization of 1-hexene with polar ω-halo-α-alkenes, demonstrating the good heteroatom tolerance of the cationic lanthanide metals that is caused by the strong electron-donating ability of these ligands. The influence of different types of comonomers on the polymerization behaviors and the microstructure of the resultant copolymer products were investigated in detail.