Theoretical thermodynamic study of Pyrazoline in the aqueoues phase at the different temperatures

The thermodynamic functions such as Enthalpy (H), Gibbs free energy (G) and Entropy (S) of Pyrazoline in the aqueous phase was theoretically studied at 5 different temperatures 25, 30, 35, 40 and 45C by using Gussian o3, software. First,the structural optimization of isolated Pyrazoline was done in the gas phase by appling the Density Functional Theory (B3LYP) level with 3-21G, 6-31G and 6-31+G(d) basis sets. Then, the calculation about the solvent effects on the stability energy of Pyrazoline were performed for water solvent using (SCRF=PCM) model at B3LYP/6-31+G(d). Moreover, vibrational frequencies were calculated in gas phase and aqueous phase on the optimized geometries at the same level of theory to obtain Enthalpy, Gibbs free energy and Entropy at 5 different temperatures. Finally the temperature effects on the thermodynamic functions were discussed.