Modulating the Magnetic Interaction in New Triple-Decker Dysprosium(III) Single-Molecule Magnets

摘要

A new type of dinuclear dysprosium(III) complex based on phthalocyanine and salicylaldehyde derivatives (HL-R), [Dy_(2)(Pc)_(2)(L-R)_(2)(H_(2)O)]·2THF (R = OCH_(3) ( 1 ), OC_(2)H_(5) ( 2 ); H_(2)Pc = phthalocyanine; HL-OCH_(3) = 2-hydroxy-3-methoxybenzaldehyde; HL-OC_(2)H_(5) = 3-ethoxy-2-hydroxybenzaldehyde), was successfully synthesized and structurally characterized. Complex 1 features a sandwich-type triple-decker structure, where two coplanar L-OCH_(3) ligands lie in the middle layer shared by two eight-coordinated Dy~(III) ions and two Pc ligands are located in the outer layer. In 2 , the introduction of an ethoxy group generates a noncoordination mode for the O_(alkoxy) atom. Magnetic studies indicate that complex 1 behaves as a zero-field single-molecule magnet with a higher energy barrier, while 2 exhibits a fast tunneling relaxation process. Theoretical calculations revealed that changes in the ligand field environment around Dy~(III) ions can significantly affect the arrangement of the main magnetic axes and further result in distinct magnetic interactions as well as different relaxation behaviors.