The Dithiirane–Thiosulfine Equilibrium Revisited—A Computational Study of Structure, Thermodynamics and Kinetics

ABSTRACT Thiosulfines as reactive S ‐centered 1,3‐dipoles undergoing (3 + 2)‐cycloadditions are still of interest in the chemistry of sulfur‐rich heterocycles. The dithiirane–thiosulfine equilibrium has been revisited to elucidate possible stabilizing effects of solvents and noncovalent interactions on formation of thiosulfines. For our study, we chose compounds that have been described by various research groups. Geometries and transition states in combination with explicit and implicit solvation models have been calculated by means of DFT calculations using the r 2 ‐Scan‐3c functional and compared to experimental results. Thermodynamic and kinetic properties have been investigated utilizing canonical variational transition state theory. Additionally, electronic structure properties have been considered to underline kinetic parameters. The first consideration of London dispersion and steric repulsion based on HFLD/ADLD calculations in the dithiirane–thiosulfine system in a solvation cluster is of special interest.