Electronic structures and energetic of metal(II)-superoxo species: a DFT exploration.

Metal-superoxo species are supposed to be a key intermediate in metalloenzyme to carry out catalytical reactions. Some biomimetic metal-superoxo species have been synthesized and characterized such as chromium/iron/nickel-superoxo species. Density functional theory (DFT) studies on metal with + 3 oxidation state superoxo species are already reported whereas less exploration encountered with + 2. Inspired from here, we have modeled metal(II)-superoxo having 14-TMC (1,4,8,11-tetramethyl-1,4,8,11- tetraazacyclotetradecane) ligand with V, Cr, Mn, Fe, Co, and Ni. Here, we have performed DFT calculations using B3LYP-D2 functional for the possible spins of all the six species and predicted the ground state. We have also computed the frontier molecular orbitals and elaborated isodensity over the molecules. Electrostatic potential maps are also drawn for studying the charge energy distribution over the species. Our calculations also reveal that a significant spin density and charge on the distal oxygen may activate the C-H/O–H bond of organic substrates. [ABSTRACT FROM AUTHOR]