Theoretical study of charge transfer complexes between antithyroid thioamides and TCNE: Thermodynamics of the complex formation

•Charge–transfer complexes between antithyroid thioamides and TCNE were studied.•The calculated equilibrium constants of complex formation nicely correlate with the donor strength.•The experimental counterparts reveal practically no such correlation.•Other chemical reactions as well as radical ions formation very probably proceed along with the π-complex formation.