三叔丁基膦亚胺苯氧钛配合物及其乙烯聚合性能

Tritertbutylphosphinimine phenoxy titanium complexes (t-Bu₃)PNTi(OAr)Cl₂ [Ar=C₆H₅(4a), 2,6-Me₂C₆H₃ (4b), 2,6-i-Pr₂C₆H₃ (4c) and 2,6-t-Bu₂C₆H₃ (4d)] were synthesized via the reaction of corresponding substituted phenol lithium salts with tritertbutylphosphinimine trichloride titanium (3). The compounds were characterized by means of ¹H NMR, ¹³C NMR, ³¹P NMR spectroscopic and elemental analyses, and the molecular structures of 3, 4b and 4d were further confirmed by single-crystal X-ray diffraction analysis. When activated with methylaluminoxane (MAO), 4a~4d displayed not only high catalytic activities, but also increasing performances on ethylene polymerization with increasing the sterical hindrance of substituents. Furthermore, 4c depicted a good thermal stability, with which the polyethylene products of different molecular weights and molecular weight distributions can be obtained by tuning the polymerization conditions.