An Unusally Diverse Array of Products Formed upon Carbonylation of a Dialkylniobium Complex

Abstract

The reaction of carbon monoxide with a β-diketiminato dimethyl niobium complex (BDI)Me₂Nb(N^tBu) is shown to lead to a variety of products whose distribution displays a remarkable dependence on the reaction conditions. Among these, the products of metal reduction, enediolate formation, and intramolecular C−H activation have been fully characterized. An investigation into the individual steps leading to these products points to a transient initial monoacyl complex, whose fate may be perturbed via reaction conditions to allow for control over the product distribution. Furthermore, the reaction of (BDI)Me₂Nb(NCMe₃) with XylNC (Xyl = 2,6-Me₂C₆H₃) yields the η²-ketimine complex (BDI)(Me₂C═NXyl)Nb(NCMe₃), whose characterization and reactivity enhance our understanding of the sequences involving CO.