Synthesis, structural characterization and magnetic behaviour of a family of [Co III2Ln III2] butterfly compounds

Abstract

We have successfully prepared and structurally characterized a family of butterfly-like [Co^III₂Ln^III₂] complexes where all magnetic properties are due to the Ln(III) ions. The complexes with Ln = Tb(1), Dy(2), Ho(3), Er(4) and Yb(5) are iso-structural. An exception is the complex with Ln = Gd(6) which strings in a one dimensional chain. The structural similarity together with the high tendency of the crystallites to align under an applied magnetic field allowed an overall DC magnetic data treatment to extract phenomenological crystal field parameters and hence to determine the ground state multiplet energy level splitting. The Dy(III) member is the only one showing slow relaxation of magnetization under zero DC applied field, while all the others need a small DC applied field.