Theoretical Study of Some Physical and Thermodynamic Properties for some Diclofenac Derivatives by using Semi-Empirical Calculations (PM3 Method)

Abstract

Nidaa A. Jasim

In this study , a Gaussian (09) program was selected using semi-experimental calculations (PM3 Method Where some thermodynamic properties were calculated, along with some kinematic properties At equilibrium Thermodynamic of the inhibitors - acetic acid] 2-(2,6- Dichloro- phenylamino)-phenyl ] acetic acid Shown the results of theoretical calculations that (COOH-R-CH2COOCH3) has the highest values of thermodynamic functions H0, G0, A0, CV ,CP ,S0) compared to the rest of the study compounds COOH-R-CH2COOC R-CH2COOCH3 COOH-R-CH2COOH , R-CH2COOH) , Where some physical properties were calculated such as orbital energies (EHOMO , ELUMO in eV), ( dipole moment μ in Debye ) , orbital energies (EHOMO , ELUMO in eV), IP (in e V) , (measurement stability ΔE ) , hardness ɳ and Electron Affinity EA ) . Plus, its formation enthalpy (ΔHr0) of these compounds were calculated by using (semi-empirical method model in AM1 MOPAC). The results showed that the compound (COOH-R- CH2COOH) Have the least value of the formation enthalpy (the more Stability) Compared to other compounds At the same time it has the most reduced value (EHOMO, ELUMO, ΔE ) , that is implies it's the most elevated active between the Studied compounds and have highest IP. Also The results showed that compound [R- CH2COOCH3] have lower electronegativity ,higher hardness(η), lower energy gap (ΔE), and lower dipole moment which might be clarified the highest anti-inflammatory The reason for this discrepancy in the results is due to the nature of the replaced group