Chiral mononuclear lanthanide complexes and the field-induced single-ion magnet behaviour of a Dy analogue

Abstract

Three pairs of homochiral mononuclear lanthanide complexes, with the general formula [LnH₄L_{RRRRRR/SSSSSS}(SCN)₂](SCN)₂·xCH₃OH·yH₂O(Ln = Dy (R/S-Dy₁), Ho (R/S-Ho₁) and Er (R/S-Er₁)), have been obtained via self-assembly between chiral macrocyclic ligands and the respective thiocyanates, all of which show a saddle-type conformation with seven-coordinated metal ions. Magnetic measurements revealed that the Dy complex shows field-induced single-ion magnet behaviour, which is rarely reported in a seven-coordinated lanthanide-based SIM encapsulated in a macrocyclic ligand. The absolute configuration of all enantiomers was determined by single crystal X-ray crystallography and confirmed by electronic CD and VCD spectra.