Unifying Molecular Weights of Highly Linear Polyethylene Waxes through Unsymmetrical 2,4-Bis(imino)pyridylchromium Chlorides.

By dealing CrCl∙3THF with the corresponding ligands (-), an array of fluoro-substituted chromium (III) chlorides (-) bearing 2-[1-(2,4-dibenzhydryl-6-fluoro- phenylimino)ethyl]-6-[1-(arylimino)ethyl]pyridine (aryl = 2,6-MePh , 2,6-EtPh , 2,6-iPrPh , 2,4,6-MePh , 2,6-Et-4-MePh ) was synthesized in good yield and validated via Fourier Transform Infrared (FT-IR) spectroscopy and elemental analysis. Besides the routine characterizations, the single-crystal X-ray diffraction study revealed the solid-state structures of complexes and as the distorted-octahedral geometry around the chromium center. Activated by either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the chromium catalysts exhibited high activities toward ethylene polymerization with the MMAO-promoted polymerizations far more productive than with MAO (20.