Probing the hydrogen bond network in the crystal structure of a sulfonamide derivative: A quantum chemical approach

A novel sulfonamide derivative, N-[2-[(5-bromo-2-chloro-4-pyrimidinyl)thio]-4-methoxyphenyl] benzene sul-fonamide, was synthesized and characterized using spectroscopic techniques. Single crystal X-ray diffraction analysis determined that the compound crystallizes in the monoclinic crystal system with the space group P21/c with Z = 8. The crystal packing of the compound was found to be largely influenced by N-H center dot center dot center dot O intermolecular interactions. Hirshfeld surface analysis with fingerprint plots was performed to visualize the intermolecular interactions present in the crystal structure. Density functional theory (DFT) studies were employed to obtain the electronic structure of the compound, including frontier molecular orbitals and their energy gap, molecular electron densities, and electrostatic potential maps. The stability of the molecule, resulting from hyper-conjugative interactions and charge delocalization, was analyzed using Natural Bond Orbital (NBO) analysis. Quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG) analysis were conducted to explore the weak interactions present in the molecule. Overall, this study provides insight into the hydrogen bonding interactions and crystal packing of sulfonamide derivatives, which have important implications for their properties in various fields such as medicinal chemistry, agrochemicals, and material science.