Tailoring the Magnetic Properties of 2D Metal-Organic Networks by Harnessing the Coordination Sphere.

Achieving magnetic ordering in low-dimensional materials remains a key objective in the field of magnetism. Herein, coordination chemistry emerges as a powerful discipline to promote the stabilization of magnetism at the nanoscale. We present a thorough study of exemplary two-dimensional metal-organic nanoarchitectures synthesized on a Au(111) substrate, which are rationalized by using surface-science techniques and theoretical calculations. By tuning the stoichiometry, two distinct phases based on the same molecular linker coordinated with Co atoms are obtained, though featuring a different coordination sphere. Remarkably, our combined experimental and theoretical results suggest that for one phase the Co centers have an out-of-plane antiferromagnetic ground state, whereas for the other the Co atoms display in-plane antiferromagnetism. These results pave new avenues for designing two-dimensional (2D) metal-organic magnets and tailoring their inherent magnetic properties.