2-Phosphanylphenolate Nickel Catalysts for the Polymerization of Ethylene

The previously unknown methallylnickel 2‐diorganophosphanylphenolates (RPh, cHex) were synthesized and found to catalyze the polymerization of ethylene. To explore the potential for ligand‐tuning, a variety of P‐alkyl‐ and P‐phenyl‐2‐phosphanylphenols was synthesized and allowed to react with [Ni(cod)2] (cod=1,5‐cyclooctadiene) or with NiBr2⋅DME and NaH. The complexes formed in situ with [Ni(cod)2] are generally active as ethylene polymerization catalysts with all the ligands tested, whereas the latter systems are inactive when 2‐dialkylphosphanylphenols are applied. Mw values, ranging from about 1000 to about 100 000 g mol−1, increase for various R2P groups in the order RPh