Theoretical Study of structural and electronic of S-Fenoprofen drug by Density Functional Calculation

In this study is to measure and evaluate the effects of electron instability, dipole-dipole interactions on the structural and electronic properties, and the structural reactivity of the Fenoprofen drug. Quantum mechanical calculations of electron density function theory were performed to obtain the structural information and the dynamic behavior of two Fenoprofen enantiomers in the gas and solvent phases, at the B3LYP/6-31G* level of theory, and Nuclear Magnetic Resonance (NMR) shielding tensors were calculated by using the Gauge Independent Atomic Orbital (GIAO) method. Also, NBO (Natural Bond Orbital) analysis was performed to calculate the effects of electron transfer due to the interaction of electron stereo and dipole moments, reactivity indices, the energy of molecular orbitals, and bond gaps energy, the density of state (DOS), and molecular atomic charge density.According to the results of the energy calculations of both enantiomers, it was found that both Fenoprofen’s enantiomers, left-handed (S) and right-handed (R) have the same energy, and also according to the experimental studies, the S-enantiomer is more stable, so the rest of the calculations have been performed on the S-Fenoprofen enantiomer. The results of theoretical calculations at the level of B3LYP/6-31G* showed that the energy gap of the enantiomer is S-Fenoprofen (Eg =5.5265 eV). Determination of reactivity indices of S-Fenoprofen indicates high electron demand and hardness (stability) and low reactivity of this compound.