Stability of single-atom iron complexes on graphene double vacancy

Abstract

The equilibrium and spatial structure of the polycyclic aromatic hydrocarbon C96H24, chosen as a model of the graphene plane, as well as the systems obtained from it by removing the diatomic molecule C2 (C94H24) and then replacing four carbon atoms with four nitrogen atoms (C90N4H24) have been studied by the DFT method (B3LYP) in the 6-31G** basis using Grimme corrections to account for dispersion interactions. In the same approximation, the energetics of the formation of a complex of an iron atom in zero oxidation degree (Fe0) with C90N4H24 ([C90N4H24Fe]0) in the square planar field of the ligand has been studied. The types of molecular orbitals of the ligand, which correspond to the symmetry of the atomic d-orbitals of the Fe atom, have been determined. Interaction diagrams of the d-orbitals of the Fe atom with some molecular orbitals of the ligand C90N4H24 of the corresponding symmetry are constructed. It is concluded that the binding of the transition metal atom on the double vacancy of the graphene plane can be rationally described based on the local symmetry of the coordination center and molecular orbitals of the ligand and the formed complex.