Single-Molecule-Magnet Behavior in the Family of [Ln(OETAP)2] Double-Decker Complexes (Ln=Lanthanide, OETAP=Octa(ethyl)tetraazaprophyrin)

Double-decker complexes of lanthanide cations can be readily prepared with tetraazaporphyrins (porphyrazines). We have synthesized and characterized a series of neutral double-decker complexes [Ln(OETAP)₂] (Ln=Tb³⁺, Dy³⁺, Gd³⁺, Y³⁺; OETAP=octa(ethyl)tetraazaporphyrin). Some of these complexes show analogous magnetic features to their phthalocyanine (P_c) counterparts. The Tb³⁺ and Dy³⁺ derivatives exhibit single-molecule magnet (SMM) behavior with high blocking temperatures over 50 and 10 K, respectively. These results confirm that, in double-decker complexes that involve Tb or Dy, the (N₄)₂ square antiprism coordination mode has an important role in inducing very large activation energies for magnetization reversal. In contrast with their P_c counterparts, the use of tetraazaporphyrin ligands endows the presented [Ln(OETAP)₂] complexes with extraordinary chemical versatility. The double-decker complexes that exhibit SMM behavior are highly soluble in common organic solvents, and easily processable even through sublimation.