Facile synthesis, single crystal analysis, and computational studies of sulfanilamide derivatives

• Two sulfanilamide derivatives were synthesized.
• Single crystal XRD results were compared with DFT data.
• Experimental and DFT based FT-IR analysis were performed to reconfirm hydrogen bonding.
• Noncovalent interaction are responsible for the stability of both compounds.
• Energies of FMOs were used to calculate the global reactivity parameters.

Antibacterial resistance is a worldwide problem. Sulfanilamide is widely used antibacterial. For the first time, we report here a simple method for the derivative synthesis of the title drugs, single crystal XRD and density functional theory (DFT) studies. The optimized molecular structure, natural bond orbital (NBO), frontier molecular orbitals (FMOs) molecular electrostatic potential studies (MEP) and Mulliken population analysis (MPA) have been performed using M06-2X/6-31G(d, p). The FT-IR spectra and thermodynamic parameters were calculated at M06-2X/6-311 + G(2d,p) and B3LYP/6-31G(d, p) levels respectively, while, the UV–Vis analysis was performed using TD-DFT/B3LYP/6-31G(d, p) method. The experimental FT-IR spectra of both compounds were also carried out to reconfirm H⋯O hydrogen bonds. The DFT optimized parameters exhibiting good agreement with the experimental data. NBO analysis explored the hyper conjugative interaction and stability of title crystals, especially, reconfirmed the existence of H⋯O hydrogen bonds between the dimers. The FT-IR, thermodynamic parameters, MEP and MPA also revealed the hydrogen bonding detail is harmonious to XRD data. As a matter of the fact, the hydrogen bonding is a significant parameter for the understanding and design of molecular crystals, subsequently; it can also play a vital role in the supramolecular chemistry. Moreover, the global reactivity descriptors suggest that title compounds might be bioactive.

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