Synthesis, spectroscopic characterization, antimicrobial activity and crystal structure of silver and copper complexes of sulfamethazine

<div><p>Silver(I) and copper(II) complexes of 4-amino-N-(4,6-dimethyl-2-pyrimidinyl) benzenesulfonamide (smz) have been synthesized and characterized by elemental analysis and infrared (IR), ¹H NMR, and UV–vis spectroscopy. [Ag(smz)(pyridine)] (<b>1</b>) crystallizes in monoclinic system with space group <i>P2</i>_<i>1</i>/<i>c</i> and <i>Z</i> = 4, while [Cu(smz)₂(pyridine)₂]·H₂O (<b>2</b>) crystallizes in triclinic system with space group <i>P-1</i> and <i>Z</i> = 2. X-ray analysis revealed that silver in <b>1</b> is four-coordinate exhibiting distorted tetrahedral geometry, while copper in <b>2</b> is coordinated to six nitrogens leading to a highly distorted octahedral geometry. The molecular structures of both <b>1</b> and <b>2</b> are stabilized by N–H⋯O and C–H⋯<i>π</i> intermolecular and C–H⋯O intramolecular interactions. Water plays a significant role in crystal packing by forming strong N–H⋯O_water intramolecular as well as O_water–H⋯N intermolecular interactions in <b>2</b>. The results of IR, UV–vis, ¹H NMR spectral data and thermal analysis for <b>1</b> and <b>2</b> suggest that the binding of silver and copper to the sulfonamidic nitrogen is in agreement with the crystal structure determination. Antimicrobial activities of silver (<b>1</b>) and copper (<b>2</b>) complexes of sulfamethazine are studied by the dilution method against <i>Staphylococcus aureus</i> and <i>Escherichia coli</i> strains.</p>