Dimers and chains of {3d–4f} single molecule magnets constructed from heterobimetallic tectons

Abstract

A tetranuclear complex and a 1-D coordination polymer with a ladder-like topology have been obtained by connecting [Ni^IIDy^III] nodes with dicarboxylato ligands: [Ni₂(valpn)₂Dy₂^III(pdca)₂(NO₃)(H₂O)₆](NO₃)·4H₂O 1, and _∞¹[Ni₂(H₂O)₂(valpn)₂Dy₂(tfa)₃]·4CH₃CN 2 (valpn²⁻ = the dianion of the Schiff base resulting from reacting o-vanillin with 1,3-propanediamine; pdca²⁻ = the dianion of 2,6-pyridinedicarboxylic acid; tfa²⁻ = the dianion of the terephthalic acid). The magnetic measurements show a ferromagnetic interaction between Ni^II and Dy^III, and that both compounds behave like SMM with strong tunnelling. The barrier of 2 (17.4 K) is higher than that of 1 (13.6 K).