Slow Magnetization Relaxation in a Family of Triangular {Co Ln } Clusters: The Effect of Diamagnetic Co Ions on the Ln Magnetic Dynamics.

The first use of the Schiff base chelate N-naphthalidene-o-aminophenol (naphH ) in Co/Ln chemistry has afforded a family of isostructural [Co Ln (OMe) (naph) (O CMe) (MeOH) ] (Ln=Tb, Dy and Er) complexes, revealing a rare {Co Ln(μ -OMe)} triangular core composed of two diamagnetic Co ions and a 4f-ion with slightly distorted square antiprismatic geometry. Alternating current (ac) magnetic susceptibility studies revealed that {Co Dy}, and its magnetic diluted analogue {Co Dy Y }, behave as mononuclear single-molecule magnets (SMMs) with similar energy barriers for the magnetization reversal, U , of ~85-90 K. SMM properties were also detected for {Co Er}, with the compound exhibiting a U of 18.7 K under an applied magnetic field of 800 Oe. To interpret the experimental magnetic results, ab initio CASSCF/RASSI-SO and DFT calculations were performed as a means of exploring the single-ion characteristics of Ln ions and comprehend the role of the diamagnetic Co ions in the magnetization relaxation of the three heterometallic compounds.