Single-molecule magnetism in {Co_2~(III) Dy_2~(III)}-aminepolyalcohol- acetylacetonate complexes: effects of ligand replacement at the Dy~(III) sites on the dynamics of magnetic relaxation

摘要

The synthesis of three new tetranuclear heterometallic Co~(III)–Dy~(III) planar butterfly coordination complexes is reported of molecular formulae [Dy_2~(III) Co_2~(III) (OH)2(teaH)2(acac)6]·MeCN (3), [Dy_2~(III)Co_2~(III) (OH)2(bdea)2(acac)6]·2H2O(4) and [Dy_2~(III)Co_2~(III) (OH)2(edea)2(acac)6]·2H2O·4MeCN (5) (teaH3 = triethanolamine, bdeaH2 = N-n-butyldiethanolamine, edeaH2 = N-ethyldiethanolamine and acacH = acetylacetone) each of which display singlemolecule magnet (SMM) behaviour. Importantly these new compounds are related to several {Co_2~(III) Dy_2~(III)} SMM compounds allowing for the study of the effect that the subtle changes in structure have on the SMM properties. Ab initio calculations are performed on 3–5, as well as on the related structural derivatives in order to gain insight on the effect the structural changes have on the dynamic magnetic behaviour.