Tuning the Ferrotoroidic Coupling and Magnetic Hysteresis in Double-Triangle Complexes {Dy3MIIIDy3} via the MIII-linker

We present the syntheses, structures, magnetic data and theoretical analyses for two families of heptanuclear clusters, wherein two staggered dysprosium(III) triangles are linked by various M(III) d-/p-block ions. The families differ in the counter-anion and are of formulae [(Dy6MIII)-M-III(OH)(8)(o-tol)(12)(MeOH)(5)(NO3)] . 4MeOH and [(Dy6MIII)-M-III(OH)(8)(o-tol)(12)(MeOH)(6)]Cl . 6MeOH (M=Cr, Mn, Fe, Co, Al; o-tol=o-toluate). We find that variation of the central metal ion M is crucial in tuning the toroidal moments on the triangular units, with diamagnetic M linking ions enhancing the ferrotoroidic coupling. By detailed simulation and analysis of various magnetic measurements, including sub-kelvin microSquid hysteresis loops, we identified the specific signature of the M linking ions' modulation of toroidal properties, including the mechanism whereby anisotropic, paramagnetic M ions lead to hysteresis profiles with larger remnant magnetisations and broader coercive fields.

Automated summary

The study focuses on two families of heptanuclear clusters, where two staggered dysprosium(III) triangles are linked by different M(III) d-/p-block ions, showing that varying the central metal ion M is crucial in tuning the toroidal moments on the triangular units. The use of diamagnetic M linking ions enhances the ferrotoroidic coupling, leading to specific modulation of toroidal properties.