theoretical thermodynamic study on the interaction between fe2+ ion and pyrazole

the interaction of fe2+ 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 acompartion between optimized structures of pyrazole molecule in aspect of thermodynamicparameters such as enthalpy (h°), gibbs free energy (g°) and entropy (s°) in presence of metallic ion(fe2+), was performed. thermodynamically analysis indicate that the relative enthalpy (h°) and gibbsfree energy (g°) are negative values but entropy (s°) is positive value for pyrazole-fe2+ complex,suggesting thermodynamic favorability for covalent attachment of pyrazole into fe2+ ion. also, theresults show with increasing dielectric constant of solvent the stability of pyrazole –fe2+ complexincreases