Structural switching from paramagnetic to single-molecule magnet behaviour of LnZn2 trinuclear complexes

Abstract

Five LnZn₂ trinuclear complexes, [Ln(NO₃){Zn(L)(SCN)}₂] (H₂L is a Schiff base ligand derived from o-vanillin and ethylenediamine; Ln = Tb 1, Dy 2, La 3, Tb_0.14La_0.864, and Dy_0.21La_0.795), were synthesised in which the Zn^II–Ln^III–Zn^II array exhibits two slightly different arrangements: 1 and 2 exhibited slightly bent arrangements, whereas 3–5 exhibited more linear arrangements. These differences in the arrangements lead to a slightly different coordination geometry around Ln^III. From the detailed studies of dynamic susceptibility, 1 and 2 were found to be paramagnetic, whereas 4 and 5 were SMMs with barriers for the flipping of magnetisation with a height of 41.2(4) K and 156(4) K, respectively.