Abstract

THEORETICAL STUDY OF THE STRUCTURE AND REACTIVITY DESCRIPTORS OF SULFAMIDES DERIVATIVES (SULFACETAMIDE, SULFAGUANIDINE, SULFAMETHOXAZOLE AND SULFATHIAZOLE)

Tahar Abbaz*, Amel Bendjeddou and Didier Villemin

ABSTRACT

In this report a complete theoretical calculations of (sulfacetamide, sulfaguanidine, sulfamethoxazole and sulfathiazole) 1-4 were performed by using Density Functional Theory (DFT) method with 6- 31G (d,p) basis set. The molecular geometries and their parameters such as bond lengths, bond angles and dihedral angles of title compounds 1-4 are determined. Also, the MEP map contour shows that the negative potential sites are generally on sulfamide function as well as the positive potential sites are around the hydrogen atoms. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. In addition, the molecular properties such as ionization potential, electronegativity, chemical potential, electrophilicity have been deduced from HOMO-LUMO analysis and the results show that the compound 3 is the more reactive. The distribution of Mulliken charges of present molecules were calculated and were interrelated with the architecture of the molecular bonds. Stability of the molecules arising from hyperconjugative interactions and charge delocalization were analyzed using natural bond orbital (NBO) analysis. The results show that electron density (ED) in the 𝜎* and π* anti-bonding orbitals and second order delocalization energies (E2) confirm the occurrence of intramolecular charge transfer (ICT) within the molecules. The dipole moment (μ) and polarizability (α), anisotropy polarizability (Δα) and hyperpolarizability (β) of the molecules 1-4 have been reported and the results show that (sulfacetamide, sulfaguanidine, sulfamethoxazole and sulfathiazole) compounds are not an attractive object for future studies of nonlinear optical properties.

Keywords: Sulfamide; density functional theory; computational chemistry; quantum chemical calculations.