Theoretical study of interaction of thiazolidine-2-thione as an anti-thyroid agent with iodine

摘要

Quantum chemical calculations were used to investigate the interaction of tautomer forms of thiazolidine-2-thione (T2T) with iodine in the gas and solution phases. The calculations show that the planar complexes are more stable than the perpendicular complexes. Also in the perpendicular complexes, the thione form is more stable than the thiol form. The calculated thermodynamic parameters in the solution phase indicate that the stability of the formed complexes increases as the dielectric constant of the solvent is increased. This result is in good agreement with the experimental results. The NBO results predict that the LP(S) sigma*(II) and LP(S) sigma*(NH) charge transfer (CT) interactions are very important in the stabilizing of the planar complexes with respect to the perpendicular complexes. In all complexes, CT takes place from T2T to I-2. Therefore, it is predicted that the donor properties of T2T are the origin of its anti-thyroid action. The atoms in molecule (AIM) analysis shows that the interactions in the planar complexes are stronger than the perpendicular complexes.