Investigation of easy-plane magnetic anisotropy in P-ligand square-pyramidal CoII single ion magnets

Abstract

In this work we report two pentacoordinated Co^II–P₄X₁ Single Ion Magnets (SIMs) based on P-donor ligands. The tetradentate ligand tris[2-(diphenylphosphino)ethyl]phosphine allows the obtention of the isostructural square pyramidal [Co(PP₃)Cl]·ClO₄ (1) and [Co(PP₃)Br]·ClO₄ (2) complexes. Consistent theoretical and experimental studies indicate that these complexes have a high spin (S = 3/2) ground state and suggest that the relaxation dynamics is governed by ground state quantum tunneling, whereas its temperature dependence is directed by optical or acoustic Raman processes.