Objective: to conduct quantum chemical modeling of a sulfur mustard molecule in an aqueous medium in the built–in parameter mode and in the mode of added molecules. After optimization by thermodynamic parameters, to study possible molecular and structural changes of mustard gas in the composition of the medium.
Methods. The Gaussian software package with the GaussView visualizer was used to construct and visualize the structure of the sulfur mustard molecule and its interaction with the aquatic environment. To carry out the calculation (calculation tipe FREQ), the standard Gaussian ab initio – Hartley-Fock (RHF) and post-Hartley-Fock (MP2) methods were chosen, which alternated with calculations based on the theory of the density function (DFT): B3LYP and B3LYP-FC. The semiempirical RPM6 method is used as a boundary factor.
Results. It is shown that only a comprehensive analysis of the state of the molecule makes it possible to identify the specific contribution of each type of interaction to the structure and properties of the molecule. In an aqueous environment, the mustard gas molecule has a high stability potential, but exposure to a real molecular environment leads to a change in polarizability, atomic charge, and dipole moment vector, and in the excited state of the molecule, one of the C1-Cl1 bonds is maximally activated, practically doubling its length.
Conclusions. Despite the very poor solubility of mustard gas in water, its intermolecular interaction with the medium leads to a redistribution of energy characteristics and the formation of a nonequilibrium polarizable state of the mustard molecule in the structure of the aquacomplex, possible further destruction with the formation of toxic products, including onium cations. Further development of the obtained results will make it possible to justify the choice of conditions for targeted activation of the mustard gas molecule for detoxification in aqueous media and body fluids.