Structural and Electronic Analysis of Sulfonamide Coordination with Platinum: A Density Functional Theory Study

Metallopharmaceuticals are compounds that contain metals and are designed for therapeutic purposes. They can be used as anticancer, antimicrobial or anti-inflammatory agents, as can sulfonamides and their complexes, which consist of a set of organic molecules containing the sulfonamide functional group (SO₂NH) and were pioneered as synthetic drugs with antibacterial activity. In this context, density functional theory was used to investigate possible descriptors for coordination and structural properties and stereoelectronic effects the of sulfonamides with Platinum. Some analyzes were carried out, including the analysis of the frontier molecular orbitals, the molecular electrostatic potential, the reactivity indices, and the evaluation of the structural and topological properties. Through analysis of the molecular electrostatic potential and frontier orbitals, it was agreed that the best region for platinum coordination is the nitrogen present in the functional amine group. The study of structural parameters prevented evaluating the behavior of sulfonamides before and after complexation with platinum, in which there was an increase in N–H and N–C bonds and a reduction in S=O and S–C bonds in the DMSO ligand, which could generate distortions in the structure of sulfonamide ligands. Based on topological properties, it was found that non-complexed sulfonamides (ligands) have stronger bonds (N–H and N–C) than in complexes. S=O and S–C bonds were stronger in complexes compared to DMSO isolated and the results obtained for the Pt–S, Pt–N, Pt–Cl and Pt–I bonds showed their partially covalent characters.