Enhanced Cooperativity in Supported Spin-Crossover Metal-Organic Frameworks

The impact of surface deposition on cooperativity is explored in Au(111)-supported self-assembled metal-organic frameworks (MOFs) based on Fe(II) ions. Using a thermodynamic model, we first demonstrate that dimensionality reduction combined with deposition on a metal surface is likely to deeply enhance the spin-crossover cooperativity, going from gamma(3D) = 16 K for the bulk material to gamma(supp)(2D) = 386 K for its 2D supported derivative. On the basis of density functional theory, we then elucidate the electronic structure of a promising Fe-based MOF. A chemical strategy is proposed to turn a weakly interacting magnetic system into a strongly cooperative spin-crossover monolayer with gamma(Au(111))(MOF) = 83 K. These results open a promising route to the fabrication of cooperative materials based on SCO Fe(II) platforms.