Theoretical Study of New Derivative of Cefotaxime-Amic Acid as a Corrosion Inhibitor

PM3 and DFT quantum mechanical calculations were employed to give further insight into the inhibition efficiency of the newly prepared cefotaxime amic acid derivative. The calculated physical properties and quantum chemical parameters correlated to the inhibition efficiency such as EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), the energy gap (ΔE(HOMO-LUMO)), hardness (η), softness (S), dipole moment (μ), electron affinity (EA), ionization potential (IE) and active site absorption..…etc., all studied and discussed at equilibrium geometry in the gas phase and at its right symmetry (C1). Experimentally the newly prepared cefotaxime derivative could be absorbed on carbon steel surface with good inhibition efficiency by offering electrons from rich hetero-atoms such as nitrogen and oxygen to unoccupied d-orbitals of Fe metal and forming antibonding orbital-feedback bonds.