Generation of bis(iminoalkyl)pyridine cobalt(I) cations under metal alkyl free conditions that polymerize ethene

Treatment of the bis(iminoethyl)- or bis(iminobenzyl)pyridine cobalt dichlorides 3a,b with ″butadiene-magnesium″ (a, R = CH3) or methyllithium (b, R = Ph) yields the corresponding bis(iminoalkyl)pyridine cobalt(I) chloride complexes 7a,b. Chloride abstraction with Li[B(C6F5)4] in toluene generates the corresponding cations (9) which are low activity catalysts for the polymerization of ethene. The pyridine-stabilized [bis(iminoethyl)pyridineCo(I)(NC5H5)+] [B(C6F5)4−] salt was characterized by X-ray diffraction.