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

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)] (1) crystallizes in monoclinic system with space group P21/c and Z = 4, while [Cu(smz)2(pyridine)2]·H2O (2) crystallizes in triclinic system with space group P-1 and Z = 2. X-ray analysis revealed that silver in 1 is four-coordinate exhibiting distorted tetrahedral geometry, while copper in 2 is coordinated to six nitrogens leading to a highly distorted octahedral geometry. The molecular structures of both 1 and 2 are stabilized by N–H⋯O and C–H⋯π intermolecular and C–H⋯O intramolecular interactions. Water plays a significant role in crystal packing by forming strong N–H⋯Owater intramolecular as well as Owater–H⋯N intermolecular interactions in 2. The results of IR, UV–vis, 1H NMR spectral data and thermal analysis for 1 and 2 suggest that the binding of silver and copper to the sulfonamidic nitrogen is in agreement with the crystal structure determination. Antimicrobial activities of silver (1) and copper (2) complexes of sulfamethazine are studied by the dilution method against Staphylococcus aureus and Escherichia coli strains.