Structure and bonding in NbX5 X = (F, Cl, Br and I) complexes: a molecular orbital perspective in the C-H bond activation

In the present work, theoretical studies of the reactivity and stability of the NbX5 complexes (X = F, Cl, Br and I) were carried out in the methane C-H bond activation. To study the chemical bonds formation of these complexes, an energy decomposition analysis was performed together with QTAIM calculations. The main results indicated that the interaction and binding energies are higher for NbF5 in relation to the halogen series. The niobium complexes gaps are influenced by the electron-egativity of the halogens and the Nb-X bonding lengths. According to the energy diagram, the electrons less connected to the bond are sigma Nb-I; on the other hand, the best electron acceptor is sigma*Nb-F. The QTAIM calculations confirmed stronger Nb-X chemical bonds in NbF5 complexes. Regarding the reactivity of the niobium complexes, the overall results indicate better thermodynamic and kinetic conditions for the NbF5 complex.