Daniel Hurtado Salinas1 2 Bart Stel1 2 Ane Sarasola3 4 Andres Arnau3 5 Klaus Kern2 6 Fernando Cometto7 1 Magalí Lingenfelder1 2

1, EPFL, Lausanne, , Switzerland
2, EPFL, Lausanne, , Switzerland
3, Donostia International Physics Center (DIPC), Donostia, , Spain
4, University of the Basque Country, Bilbao, , Spain
5, University of the Basque Country, Donostia, Donostia, Spain
6, Max Planck Institute for Solid State Research, Stuttgart, , Germany
7, Universidad Nacional de Córdoba, Córdoba, , Argentina

Photosynthesis, the model system for energy conversion, uses CO2 as its starting reactant to convert solar energy into chemical energy, i.e. organic molecules or biomass. The ratedetermining step of this process is the immobilization and activation of CO2, a carboxylation reaction catalyzed by the enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase). Inspired by the active site of RuBisCO, we design nanostructures that self-assemble on solid surfaces. Here we show the fabrication of the first hybrid networks using an alkaline earth metal (Group 2): magnesium (Mg) and organic molecules of terephthalic acid (TPA) and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) by direct deposition onto clean metal substrates [Cu (100) and Mg (0001)] under Ultra High Vacuum (UHV) conditions at room temperature (RT). We track their reactivity and dynamic response to CO2 and O2 in situ by Scanning tunneling microscopy (STM) and X-Ray Photoelectron Spectroscopy (XPS), supported by density functional theory (DFT) calculations. Specific phase transformations and active sites are identified with atomic resolution upon gas exposure at RT. Our study shows that is possible to reverse the structure-function equation to design selfassembled 2D functional networks inspired in biological active centers.