Coordination compounds of chromium (+3) and vanadium (+3) and (+5) with 2,6-bis(diphenylhydroxymethyl)pyridyl ligand: Synthesis and study of catalytic activity in the polymerization of ethylene

Coordination compounds of chromium (III) and vanadium (III) and (V) with 2,6-bis(diphenylhydroxymethyl)pyridine have been synthesized. Composition and properties of the obtained complexes have been evaluated by NMR, IR spectroscopy, X-ray diffraction, and elemental analysis. Depending on the nature of the metal and the synthesis conditions, there are various types of coordination state of the terdentate pyridine ligand in the obtained complexes: it can bind either as a dianionic, bisalkoxide, terdentate (compounds 5, 7, 8, 9), monoanionic, alkoxide/alkohol, terdentate (compounds 4, 6) or as a neutral, bisalkohol, terdentate ligand (compound 3). Coordination compounds of chromium were found to be incapable of catalytic polymerization of ethylene. Catalytic activity of vanadium (III) and (V) complexes in this reaction varied between 85 and 578 kg PE/mol V h after activation with diethylaluminum chloride, depending on the V/Al ratio.