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

A tetranuclear complex and a 1-D coordination polymer with a ladder-like topology have been obtained by connecting [(NiDyI)-Dy-II-I-II] nodes with dicarboxylato ligands: [Ni-2(valpn)(2)Dy-2(III)(pdca)(2)(NO3)(H2O)(6)](NO3)center dot 4H(2)O 1, and(infinity) (1)[Ni-2(H2O)(2)(valpn)(2)Dy-2(tfa)(3)]center dot 4CH(3)CN 2 (valpn(2-) = the dianion of the Schiff base resulting from reacting o-vanillin with 1,3-propanediamine; pdca(2-) = the dianion of 2,6-pyridinedicarboxylic acid; tfa(2-) = 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).