Pure Trinuclear 4f Single-Molecule Magnets: Synthesis, Structures, Magnetism and Ab Initio Investigation

Abstract

A family of linear Dy3 and Tb3 clusters have been facilely synthesized from the reactions of DyCl3, the polydentate 3-methyloxysalicylaldoxime (MeOsaloxH2) ligand with auxiliary monoanionic ligands, such as trichloroacetate, NO3-, OH-, and Cl-. Complexes 1-5 contain a nearly linear Ln3 core, with similar Ln⋯Ln distances (3.6901(4)-3.7304(3) Å for the Dy3 species, and 3.7273(3)-3.7485(5) Å for the Tb3 species) and Ln⋯Ln⋯Ln angles of 157.036(8)-159.026(15)° for the Dy3 species and 157.156(8)-160.926(15)° for the Tb3 species. All three Ln centers are bridged by the two doubly-deprotonated [MeOsalox]2- ligands and two of the four [MeOsaloxH]- ligands through the N,O- η2-oximato groups and the phenoxo oxygen atoms (Dy-O-Dy angles=102.28(16)-106.85(13)°; Tb-O-Tb angles=102.00(11)-106.62(11)°). The remaining two [MeOsaloxH]- ligands each chelate an outer Ln III center through their phenoxo oxygen and oxime nitrogen atoms. Magnetic studies reveal that both Dy3 and Tb3 clusters exhibit significant ferromagnetic interactions and that the Dy3 species behave as single-molecule magnets, expanding upon the recent reports of the pure 4f type SMMs. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.