Theoretical study of stability of dinitrosyl iron(i) complexes with thiocarbonyl ligands

The binding energies of thioligands L of the general formula S=CR₁R₂ in dinitrosyl iron complexes [Fe(NO)₂L₂]⁺ (DNICs) were calculated using density functional theory methods. The TPSSH functional with the def2-TZVP basis set and the PCM–SMD polarizable continuum model were used. The reactions of abstraction of 14 thioamide and thiocarbonyl ligands and their replacement with a H₂O molecule in the gas phase and aqueous medium were studied. It is found that the bond energies in the gas phase do not accurately characterize the stability of DNICs because of the high energy of reorganization of the reaction products upon their transition into the aqueous phase. Analysis of the structure—activity correlations revealed linear regression dependences of Fe—S bond energies on partial charges on S atoms and electronegativity of thioligands.