A series of trinuclear Cu^IILn^IIICu^II complexes derived from 2,6-di(acetoacetyl)pyridine: Synthesis, structure, and magnetism

A series of trinuclear Cu^IILn^IIICu^II complexes with the bridging ligand 2,6-di(acetoacetyl)pyridine have been prepared by one-pot reaction with Cu(NO₃)₂·3H ₂O and Ln(NO₃)₃·nH₂O in methanol. X-ray crystallographic studies for all the complexes indicate that two L^2- ligands selectively sandwich two Cu(II) ions with the 1,3-diketonate entities and one Ln(III) ion with the 2,6-acetylpyridine entity to form a trinuclear CuLnCu core bridged by the enolate oxygen atoms. Cryomagnetic properties of the complexes are studied with respect to the electronic structure of the Ln ion.