Theoretical thermodynamic study on the interaction between Mn2+ ion and Pyrazole

The interaction of Mn2+ ion with Pyrazole was theoretically studied by Gussian 03, software at HF/ (LanL2DZ+6-31G) and HF/ (LanL2DZ+6-31G (d)) levels in gas phase and solution. In this study a comparison between optimized structures of Pyrazole molecule in aspect of thermodynamic parameters such as enthalpy (H), Gibbs free energy (G) and entropy (S) in presence of metallic ion (Mn2+), was performed. Thermodynamically analysis indicate that the relative enthalpy (H) and Gibbs free energy (G) are negative values but entropy (S) is positive value for Pyrazole-Mn2+ complex, suggesting thermodynamic favorability for covalent attachment of Pyrazole into Mn2+ ion. Also, the results show with increasing dielectric constant of solvent the stability of Pyrazole –Mn2+ complex increases.

Keywords:

Pyrazole-Mn2+ complex , Thermodynamic parameters , Solvent effects