Rearrangement of Imidazolidine to Piperazine Rings in the Presence of DyIII

The formation of imidazolidines from secondary amines and aldehydes is well known. This small cycle can act as a nitrogen donor, and it is usually stable when it coordinates to metal ions. Sometimes, imidazolidines acting as ligands undergo breaking of the C-N bond when coordinating to the metal center, yielding related amines. However, the reorganization of the imidazolidine into a piperazine ring is quite an unusual process. In this work, we describe the transformation of a zinc complex with a ligand containing two imidazolidine moieties into a zinc complex with a piperazine fragment as donor, in the presence of a dysprosium salt.