Bis(imino)pyridine Complexes of the First-Row Transition Metals: Alternative Methods of Activation

The use of AlEt3 (TEA) in combination with [Ph3C][Al((OBuF)-Bu-t)(4)] (TA) for the activation of a range of bis(imino)pyridine complexes of vanadium, chromium, iron, and cobalt is reported. It is shown that this activator combination successfully replaces MMAO, in some cases showing improvements in terms of activity and productivity. Furthermore, when activities and productivities are considered in terms of the aluminum center (MMAO vs TEA), the true cost driver in the commercialization of most catalyst systems, then in nearly all cases a significant improvement is seen.