Focusing on specific features, the DOS bands at ~0 eV and ~3 eV are dominated by Fe contributions, reflecting the significant role of Fe orbitals in bonding interactions and charge transfer with the surface (Figure and). Furthermore, the DOS bands below -2 eV and above 3 eV are dominated by carbon contributions, indicating that these states are associated with the πsystem of the Cp rings. These π-states play a crucial role in the interaction with the metal surface, contributing to the stability and electronic modification of the adsorbed E-Fc. The band at approximately -2.5 eV in the DOS spectra of isolated E-Fc and S-Fc diminish notably upon adsorption onto the Au(111) surface in a vertical configuration (E-Fc(⏊)/Au and S-Fc(⏊)/Au).