Solvent orientation in the crystal lattice producing distinct magnetic dynamics in two binuclear Dy(iii) polymorphs with a polydentate Schiff base ligand

Abstract

Two Dy(III) polymorphs, [Dy(Clapi)]₂·(CH₂Cl₂)₂ (H₃Clapi = 2-(2′-hydroxy-5′-chlorophenyl)-1,3-bis[3′-aza-4′-(2′′-hydroxy-5′′-chlorophenyl)prop-4′-en-1′-yl]-1,3-imidazolidine), have been obtained, crystallizing in space groups P2₁/c (1a) and C2/c (1b), respectively. Both 1a and 1b have an identical eight-coordinated Dy(III) configuration with D_4d symmetry; their only difference is the lattice orientation of the solvent molecule CH₂Cl₂. Alternating current (ac) magnetic susceptibility measurements reveal that they exhibit distinct magnetic behaviours. Theoretical calculations indicate that the exchange interactions play a vital role in the magnetic behavior of the polymorphs. This work presents a rational model to explore the magneto-structural relationship in both experimental and theoretical aspects of Dy(III) single-molecule magnets.