Arylimido zirconium and titanium complexes: characteristic structures and application in ethylene polymerization

Abstract

Dimeric anilidolithium (ArHNLi·Et2O)2 (Ar=2,6-iPr2C6H3) reacted with zirconium tetrachloride in THF to give the heterometallic zirconium–lithium complex [(Et2O)2Li(μ-Cl)2(ArHN)(ArN=)Zr(μ-Cl)]2 (C1) and with titanium tetrachloride in toluene to give the titanium complex [(ArN=)TiCl2·(Et2O)2] (C2) each in good isolated yields. Their molecular structures in the solid state were confirmed by X-ray diffraction analysis. Upon activation with methylaluminoxane, both arylimido zirconium and titanium complexes exhibited good catalytic activities toward ethylene polymerization.

Recent advancements in N-ligated group 4 molecular catalysts for the (co)polymerization of ethylene

“…At 50 °C and the ethylene pressure at 10 atm, 47/MAO reached a maximum activity of 1.47 × 105 g•mol-1•h-1 with an Al:Zr molar ratio of 2000:1. The arylimido zirconium-lithium complex 51 and arylimido titanium complex 52 were synthesized and characterized and showed some differences in nuclearity, coordination and geometry (Figure 20) [137,138]. Notably in 51, each zirconium center in the dimer was sixcoordinate while the single titanium center in 52 was five-coordinate.…”