Computational chemistry study of sulfide oxidation mediated by peroxo complexes of MO and w

Abstract

Sulfide oxidation is a very important chemical process for the synthesis of sulfoxides and sulfones as well as for the oxidative desulfurization of transportation fuels. In particular, the process of oxidation of sulfides by Mimoun-type peroxo complexes of formula MO(O2)2L1L2 ou MO(O2)2L1-L2 (M = Mo ou W; L1, L2 are donor ligands; L1-L2 is a bidentate ligand) has been significantly reported because it is considered a efficient, selective, and ecologically benign method. However, so little is known about the molecular mechanism of oxygen atom transfer from Mimoun`s complexes to sulfurous compounds. The main aim of this research project is to investigate by means of electronic structure calculations the molecular mechanism of sulfide oxidation mediated by Mimoun´s complexes. It is expected to establish the origin of the reactivity, if any, of theses complexes in terms of their own electronic and structural properties. For this purpose will be scrutinized relationships (linear free energy relationships) between calculated thermodynamic and kinetic parameters of the reaction (via transition state theory) and the calculated electronic and structural properties of the reactants such as bond distance, orbital composition, orbital energy, charge distribution, electrophilicity, etc. Molecular properties will be calculated by using recognized theoretical approaches, namely, charge decomposition analysis (CDA), topological analysis of the electron localization function (ELF), conceptual density functional theory (global and local reactivity descriptors such as electronegativity, hardness, softness, electrophilicity, etc), among others. It would be pointed out that this project is closely connected to a strong scientific collaboration maintained with the computational chemistry group of Professor Juan Andres (Universitat Jaume I, Spain) and with the experimental research group of Dr. Quezia Cass (DQ/UFSCar). (AU)