Tuning the molecular antenna effect using donor and acceptor substituents on the optical properties of the [(C₅F₅)₂ThMCp₂]²⁺ and [(C₅F₅)₂ThMCpL₂]⁺ complexes, where M = Fe, Ru and Os and L = CO and C₅H₅N

In the present work, a theoretical methodology based on DFT is used to establish the effects of the electron rearrangements on the optical properties in a series of unsupported Th-M (transition metal) complexes of the form: and where Cp = C₅H₅ ^-, Cp′′ = C₅F₅ ^-, L = CO, C₅H₅N (py) and TM = Fe, Ru, Os. The role of the [MCp(L)₂] chromophore is determined using different theoretical approaches like Morokuma-Ziegler energy decomposition analysis combined with the Extended Transition State with Natural Orbitals of Chemical Valence (ETS-NOCV). An important electron-donation and back-donation synergic interaction was found, which determines the degree of covalence of the chemical bond. Finally, the spin-orbit-ZORA calculation shows the possible Near Infra-Red (NIR) emission induced by the transition metal chromophore accomplishing the antenna effect that justifies the sensitization of the actinide complexes.