Structure, Dynamics, and Magnetic Shieldings of Permanganate Ion in Aqueous Solution. A Density Functional Study

Car−Parrinello molecular dynamics simulations have been performed for MnO 4 - in the gas phase and in aqueous solution. Dynamic averaging at ca. 300 K affords only minor changes for the mean Mn−O bond length with respect to the optimized value r e = 1.622 Å (BP86 value). Magnetic shieldings, evaluated at the GIAO-B3LYP level for snapshots along the trajectories, decrease upon going from the equilibrium values to the dynamic averages in water. For 55 Mn and 17 O, the resulting σ 300K − σ e values amount to −36 and +31 ppm, respectively. The structure of the solvation shell around permanganate ion in water is characterized by the mean number of hydrogen-bonded solvent molecules (approximately 4) and by the g MnO pair correlation function.