Tuning quantum tunnelling of magnetization through 3d–4f magnetic interactions: an alternative approach for manipulating single-molecule magnetism

Abstract

The magnetic relaxation and magnetization blocking barriers of butterfly complexes, [Dy₂Zn₂(L)₄(NO₃)₂(CH₃OH)₂] (1), [Dy₂Mn₂(L)₄(NO₃)₂(DMF)₂] (2) and [Dy₂Co₂(L)₄(NO₃)₂(DMF)₂]·2DMF (3) (H₂L = (E)-2-ethoxy-6-(((2-hydroxyphenyl)imino)methyl)phenol), were systematically investigated. The change of SMM behavior originating from the purposeful replacement of two Zn^II sites in 1 with Mn^II and Co^II was elucidated by a combined experimental and theoretical study. The quantum tunnelling of magnetization (QTM) was observed in 1. Contrarily, it was quenched in 2 and 3 by spin–spin exchange. A detailed comparative study on these closely-related model complexes reveals the remarkable changes of the ligand field splitting, anisotropy of the Dy-coordinated moiety and the total exchange spectrum due to the replacement of Zn^II with Co^II and Mn^II.