Dimensional Transformation of Molecular Magnetic Materials.

Two-dimensional (2D) magnetic layered materials have revolutionized size dependent magnetism to manipulate spin-based devices. However, it has been challenging to artificially create 2D magnetic materials from three-dimensional (3D) crystal structures with a variety of material groups. Here, we present the dimensionality manipulation via cation exchange of a 3D Prussian blue analogue [RbMnFe(CN)] toward a 2D magnetic sheet [(K,Rb)(V,Mn)(Cr,Fe)(CN)] with the magnetic ordering temperature rising from 12 to 330 K. Such a 2D magnetic sheet achieves crystalline V-Cr coordination in the Prussian blue lattice with pronounced anisotropy and stimuli responsiveness. The pressure dependent magnetic tunability of such 2D networks is predicted using first-principles calculations and demonstrated using the phase transitions of the hydrogel. This previously unobserved phenomenon of dimensional manipulation of a bulk crystal structure provides a rational strategy to expand the diversity and chemical compositions of 2D molecular magnetic material libraries.