Magnetic Exchange Interactions in Symmetric Lanthanide Dimetallics

We report the synthesis and characterization of two symmetric homo-dimetallic lanthanide complexes based on methyl-substituted 8-hydroxy-8-quinoline (HMeQ). The aryloxo-bridged core gives rise to weak magnetic coupling between pairs of ErIII and YbIII ions, as revealed by magnetic and EPR studies. EPR of magnetically dilute species, coupled with CASSCF-SO calculations, allows modelling of the EPR spectra of the exchange coupled species and the magnetic data simultaneously. This work adds to the database of exchange coupled {Ln}2 molecules which have been thoroughly characterised by EPR spectroscopy and modelled using an Seff = 1/2 approach to describe the interaction of ground Kramer’s states, and highlights the differences between centro-symmetric and asymmetric dimetallics.