The Identification of the Products of the Reaction of Iron Complexes by the Vibration Spectrum by Way of Example of an Iron [Fe(OH)2(H2O)2]+ Hydroxo Cation in an Aqueous Medium

The change in the vibration spectrum of an iron [Fe(OH)₂(H₂O)₂]⁺ hydroxo cation during its interaction with peroxynitrite [NO–O₂]⁻ in an aqueous medium described by the PCM–SMD model is studied to identify the reaction products, first of all, nitrogen dioxide. The quantum chemical calculation of the complex by CASSCF is identical to that earlier used in the description of the reactions in the active site of the tubercle bacillus M. tuberculosis (trHbN). The reaction products in these processes are compared, and the most characteristic frequency of vibrations which makes it possible to detect the appearance of nitrogen dioxide is found. The energy effect in the reverse process, capture of nitrogen dioxide by an iron complex, is estimated.