Theoretical investigation of molecular and electronic structure changes of the molecular magnet Mn₁₂ cluster upon super-reduction

Density functional theory calculations on the neutral [Mn₁₂]⁰ molecular magnet and super-reduced [Mn₁₂]^8- cluster were employed to investigate the experimental geometrical changes observed during discharging in a molecular cluster battery. It was found that for relevant low-spin states the eight electrons added in [Mn₁₂]^8- are mainly added to the outer eight Mn atoms, causing elongation of the bonds between outer Mn and their surrounding O atoms, while the inner Mn₄ cluster is less affected by the reduction. Schematic representation of the spin density of the neutral [Mn₁₂]⁰ cluster and its super-reduced state [Mn₁₂]^8-, for which several possible spin states were found.