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

Abstract A family of linear Dy 3 and Tb 3 clusters have been facilely synthesized from the reactions of DyCl 3 , the polydentate 3‐methyloxysalicylaldoxime (MeOsaloxH 2 ) ligand with auxiliary monoanionic ligands, such as trichloroacetate, NO 3 − , OH − , and Cl − . Complexes 1 – 5 contain a nearly linear Ln 3 core, with similar Ln⋅⋅⋅Ln distances (3.6901(4)–3.7304(3) Å for the Dy 3 species, and 3.7273(3)–3.7485(5) Å for the Tb 3 species) and Ln⋅⋅⋅Ln⋅⋅⋅Ln angles of 157.036(8)–159.026(15)° for the Dy 3 species and 157.156(8)–160.926(15)° for the Tb 3 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 ‐η 2 ‐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 Dy 3 and Tb 3 clusters exhibit significant ferromagnetic interactions and that the Dy 3 species behave as single‐molecule magnets, expanding upon the recent reports of the pure 4f type SMMs.