Fig. 3: Theoretical insights into the reactivity of the tpy-Co sites.
From: On-surface synthesis of tailored organic platforms for single metal atoms
a Binding energies of several gases to the cobalt site of the tpy-Co system and of a reference Co-porphyrin. Optimized structures on A(111) obtained by DFT with periodic boundary conditions are sketched in the middle and right panels. The PBE exchange correlation functional is used with vdW corrections as proposed by Grimme (see “Methods”). These values were obtained by calculating the energy difference between the structure with the gas molecule interacting with the cobalt sites and adsorbed on the bare Au(111) surface. Multiple adsorption geometries were considered for the gas molecules, and the lowest energy were taken into account. b DFT-optimized gas phase molecular structure of a model tpy-Co system, which represents the lateral extensions of the 1D polymers synthesized herein. c PDOS for the tpy-Co, where positive (negative) values in the y-axis correspond to the spin-up (spin-down) channel. The highest occupied molecular orbital (HOMO) levels are indicated by the gray dashed lines. d Energy diagram of the frontier molecular orbitals of the tpy-Co. e DFT-optimized gas-phase molecular structure of a Co-porphyrin. f PDOS of the Co-porphyrin. g Energy diagram of the frontier molecular orbitals of the Co-porphyrin system. Isovalues for the probability densities in d,g are 0.012 bohr-3. The PBE0 functional with the def2-TZVP basis set was used in the gas-phase calculations.
