Síntese, aspectos moleculares e supramoleculares e avaliação antibacteriana de um polímero de coordenação de prata(I) e do bloco construtor trimesato de amônio

Abstract

The search for new materials that display antimicrobial properties is a response to an increase in bacterial strains that are resistant to antibiotics. In this context, coordination polymers are a uniquely apt class of compound to investigate for this purpose. As a hybrid material containing metal ions and organic ligands, its potential functions are dependent on the appropriate choice of precursors materials used in the synthetic process. In this work, we report the synthesis of two new materials, a silver(I) coordination polymer of formula {[Ag(bipy)]3·(trim)·8(H2O)·(CH3OH)}n (A) and the ammonium trimesate salt, (NH4)3(trim)·2H2O (B), a potential building block for the synthesis of supramolecular structures. Compounds A and B were characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy (IR), thermogravimetric analysis (TG), and Hirshfeld surface analysis. The analysis of the crystal structure of the coordination polymer A revealed a cationic polymeric chain based on silver(I) and 4,4’-bypiridine, a trimesate counterion, eight water molecules, and one methanol molecule. In B, the charge of the trimesate anion is balanced by three ammonium counterions, and the unit cell still has two crystallization water molecules. The structural data showed that the hydrogen bonds are the main non-covalent interaction that holds the supramolecular architectures of A and B. Antibacterial activity was tested using broth macro dilution assay against Gram-positive Staphylococcus aureus (S. aureus) and Gramnegative Escherichia coli (E. coli) bacteria. Compound A has displayed bactericide properties for both Gram-positive (S. aureus, MIC: 16 mg L-1 and MBC: 128 mg L-1) and Gram-negative (E. coli, MIC: 32 mg L-1 and MBC: 64 mg L-1) bacteria, while compound B did not present antimicrobial activity. Compound B is a potential building block of analogous supramolecular structures of A and is already being used in our research group.