Associative interactions of tert-butyl hydroperoxide with halide anions: intermolecular dynamics and NMR spectra parameters

Hydroperoxides are widely used as effective initiators of radical-chain processes. These compounds are sources of free radicals in polymerization processes and in the oxidation of organic compounds. Various catalytic systems are often used to regulate the reactivity of hydroperoxides. Quaternary ammonium salts are effective environmentally friendly catalysts for the radical decomposition of hydroperoxides and peroxides. The catalytic effect of quaternary ammonium salts in hydroperoxide decomposition reactions is due to the formation of the intermediate complex “hydroperoxide - catalyst”. The quaternary ammonium salt anion plays a key role in the chemical activation of the hydroperoxide and therefore the nature of this anion directly determines the rate of the decomposition reaction.

The paper presents the results of theoretical studies of the molecular geometry, electronic structure and NMR spectra parameters of intermediate associates of tert-butyl hydroperoxide with halide anions of quaternary ammonium salts (Cl^–, Br^–, I^–). Molecular modeling data are discussed along with corresponding experimental values. The main markers of intermolecular interactions were the bond lengths, the torsion angles of the hydroperoxide fragment as well as the chemical shift of the hydroperoxide group protons. Experimental NMR ¹Н spectra of the hydroperoxide and hydroperoxide - quaternary ammonium salt solutions were recorded on a Bruker Avance instrument (400 MHz).

The results obtained in the paper can be used to predict a more probable model of the hydroperoxide - quaternary ammonium salt complex.