Robust high-spin Fe2+ centers in 2D TCNQ-based metal–organic frameworks

Abstract

Two-dimensional metal–organic frameworks (2D MOFs) are atomically thin materials that combine the properties of organic molecules with the structural characteristics of crystalline inorganic solids. Their unique magnetic and electronic properties arise from the interaction between transition metal centers and organic linkers. This study focuses on the high-spin Fe²⁺ centers in a 7,7,8,8-tetracyanoquinodimethane (TCNQ)-based 2D MOF, where hybridization between Fe 3d states and π-symmetric orbitals of TCNQ ligands stabilizes regularly spaced magnetic centers. X-ray magnetic circular dichroism (XMCD) measurements confirm the robustness of these magnetic properties across various substrates, including graphene and gold.