Back Cover: Theoretical investigation of molecular and electronic structure changes of the molecular magnet Mn 12 cluster upon super‐reduction (Phys. Status Solidi RRL 6/2014)

Quantum chemical investigations of the neutral [Mn 12 O 12 (CH 3 COO) 16 (H 2 O) 4 ] 0 molecular magnet cluster (abbreviated as [Mn 12 ] 0 ) are complicated by the energetic multitude of spin states due to weak spin–spin couplings between the twelve Mn centers. The situation becomes even more serious for this cluster in its super‐reduced [Mn 12 ] 8– state, which was recently introduced by the Awaga group [Wang et al., Chemistry – Asian J. 6 , 1074 (2011)] as the cathode‐active material of the molecular cluster battery (MCB). In their work on pp. 517–521 , Nishimoto et al. theoretically investigate the geometrical changes observed experimentally during discharging in the MCB using standard geometry optimization and direct first principles molecular dynamics simulations to include temperature effects. The spin‐polarized, broken‐symmetry density functional theory (DFT) calculations on 15 candidate electronic states suggest that for relevant low‐spin states the eight electrons added in [Mn 12 ] 8– are mainly, but not completely transferred to the outer eight Mn atoms, causing elongation of the bonds between outer Mn and their surrounding O atoms, while the inner Mn 4 O 4 cluster is less affected by the reduction (only one electron can be picked up in the lowest‐energy spin state).