The Shastry–Sutherland lattice in two-dimensional magnetic lanthanide metal–organic frameworks†

Abstract

Two-dimensional magnetic lanthanide materials are highly sought after in the advancement of spintronic devices that feature atomically thin structures. While the Shastry–Sutherland (SS) lattice presents a promising platform for such materials, its application in metal–organic systems has been constrained by synthetic complexities. Here, we developed a highly effective method to achieve the required metal–organic compound of the SS lattice through a strategy involving dissolution–crystallization of dimer compounds, pursuant toward the distinctive conjugated dihydrazide-bridged orthogonal-dimer structure. The resulting compound, DyCl₂ (ppch)_0.5·2DMF (H₂ppch = N‘-(pyrazine-2-carbonyl)pyrazine-2-carbohydrazide, 1), exhibited a distorted SS lattice. Notably, the easy axis of the Dy(III) ion was nearly perpendicular to the two-dimensional plane, fostering the coexistence of ferromagnetic and antiferromagnetic interactions within the structure. Furthermore, the compound demonstrates complex slow relaxation of magnetization. Theoretical computations revealed that the magnetic interactions arising from the polymerization of dimers significantly affect the relaxation dynamics of 1. This work provides a novel approach for synthesizing two-dimensional magnetic compounds, thereby paving the way for advanced materials in the field.