Spectral and quantum-chemical investigation of interactions in supra-molecular systems: cucumin - decametoxin - silica in aqueous solutions

The peculiarities of the interaction in the supramolecular system: the natural hydrophobic polyphenol curcumin - the antiseptic cationic surface-active substance decamethoxin - highly dispersed silica was revealed by the spectrophotometric method. It was established that significant changes in the spectral characteristics of curcumin in aqueous solutions and on the surface of the sorbent depend on the concentration of this cationic surfactant, which can exist in the solution in the form of monomers, associates, and micelles. The PM7 method and the COSMO solvation model, implemented in the MOPAC2016 software package were used to determine the mechanism of adsorption of the supramolecular complex of curcumin (in ketone or enol form) with decamethoxine on the silica surface. The distribution of electrostatic and hydrophobic potentials of the studied molecules, calculated by the FieldView 2.0.2 method (Flare software package), indicates a significant contribution of hydrophobic interactions in the formation of supramolecular complexes of curcumin with decamethoxin in solution and on the surface of silica. The obtained results are of practical importance and can be used in the development of new more effective drugs containing bioactive curcumin, antiseptic decamethoxine and enterosorbent silicon dioxide.