Cobalt Coordination Induced Functionalized Molecular Clefts: Isolation of {Co^III−Zn^II} Heterometallic Complexes and Their Applications in Beckmann Rearrangement Reactions

The present work shows that the Co3+ coordination to the deprotonated pyridine-amide ligands orients the noncoordinated or hanging pyridine rings, thus furnishing a cleft in which Zn2+ ions coordinate. The building block approach points out a strategy to incorporate a Lewis acidic metal center in the periphery. This strategy has been used to synthesize Co3+-centered−Zn2+-peripheral heterobimetallic complexes. These heterobimetallic complexes have been thoroughly characterized including structural studies and have been successfully shown to catalyze the Beckmann rearrangement of the aldoximes and ketoxime to their respective amides.