A Comparative Computational Study of the Structural and Electronic Properties of Paracetamol and its Alkyl and Sulfate Derivatives
Abstract
In this paper , there is a comparative analysis of the computations in chemistry about the structures and properties of paracetamol (S1) and its two series of derivatives: alkyl derivatives such as phenacetin (S2), N-(4-propoxyphenyl)acetamide (S3), and N-(4-butoxyphenyl)acetamide (S4), along with the sulfate derivative, 4-acetamidophenyl hydrogen sulfate (S5). The objective was to find the conformational Minimum Energy of the structures, in addition to the calculation of total electronic energy, dipole moment, HOMO-LUMO values, chemical stability, chemical hardness, and energy gap ΔE (Egap). The results showed that the increase in the chain length of the hydrocarbon group (S1 to S4) caused the gap between the energies of HOMO and LUMO to reduce. In the case of phenacetin (S2), the energy gap was the highest and the chemical hardness, making it the most stable compound and least polarizable within the alkylated set of compounds. Paracetamol (S1), on the other hand, had the lowest energy gap and the least chemical hardness, making it highly reactive. A change in the electronic nature of the molecule has been noted. The electronic energy of the molecule is greatly reduced to -1050.72 {Hartree}, owing to the effect of the electron-withdrawing ability of sulfur and oxygen and the stabilization of charge density through resonance. Moreover, the LUMO orbital of S5 has been raised to a positive energy level (+0.056 Hartree).