Mechanism for the direct oxidation of benzene by chromium oxide cluster CrO₃: A theoretical and computational approach

Abstract In this research, the oxidation process of benzene to phenol facilitated by a CrO 3 cluster was comprehensively analyzed using density functional theory calculations at the TPSSh/aug‐cc‐pVDZ level. Investigations were conducted on both singlet and triplet potential energy surfaces (PES). The differences in the stability of some of the stationary points on the PES were explained by natural bond orbital analysis and the interaction area indicator tool. The findings reveal that the primary interaction between benzene and CrO 3 involves a weak back‐donation from benzene's π‐orbital to the CrO 3 cluster. The rate‐limiting step of the reaction involves the spin crossover from the singlet to the triplet state. In the gas phase, the minimum energy crossing point (MECP) between the singlet and triplet surfaces was found to be at a slightly lower energy than those of the reactants, −0.72 kcal mol −1 . The influence of solvent polarity on this process was examined, revealing that higher polarity enhances the oxidation of benzene to phenol by CrO 3 .