GREMMLENZ UNICAMP

The sulfonamide drug Silver Sulfadoxinate (SFX) underwent a reaction with Ag+ ions in an aqueous medium, leading to the formation of a novel silver(I) complex, denoted as AgSFX. The comprehensive characterization of AgSFX involved chemical, spectroscopic, and structural methods. Elemental, ESI-TOF mass spectrometric, and thermal analyses collectively suggested the empirical formula [Ag(C12H13N4O2S)]. Infrared spectroscopic measurements revealed ligand coordination to Ag(I) through the nitrogen atoms of the deprotonated sulfonamide group and the pyrimidine ring, as well as through oxygen atom(s) of the sulfonamide group.

The coordination hypothesis was supported by 13C and 15N SS-NMR spectroscopy, along with an unconventional structural characterization based on X-ray powder diffraction data. The latter unveiled AgSFX’s crystallization as centrosymmetric dimers with a robust Ag⋯Ag interaction (2.7435(6) Å), facilitated by exo-bidentate N,N′ bridging ligands and the formation of an eight-membered ring with a [AgNCN]2 sequence, nearly planar. The involvement of oxygen atoms from sulfonamide residues resulted in a 1D coordination polymer, contributing to the complex’s limited solubility in common solvents.

Beyond the analytical, spectroscopic, and structural details, the antibacterial properties of AgSFX were evaluated using disc diffusion methods against Escherichia coli, Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive) bacterial strains. AgSFX exhibited notable activity against both Gram-positive and Gram-negative bacterial strains, comparable to the activities of silver sulfadiazine.

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