Ligand effects on the structural dimensionality and antibacterial activities of silver-based coordination polymers

Abstract

Four Ag-based coordination polymers [Ag(Bim)] (1), [Ag₂(NIPH)(HBim)] (2), [Ag₆(4-NPTA)(Bim)₄] (3) and [Ag₂(3-NPTA)(bipy)_0.5(H₂O)] (4) (HBim = 1H-benzimidazole, bipy = 4,4′-bipyridyl, H₂NIPH = 5-nitroisophthalic acid, H₂NPTA = 3-/4-nitrophthalic acid) have been synthesized by hydrothermal reaction of Ag(I) salts with N-/O-donor ligands. Single-crystal X-ray diffraction indicated that these coordination polymers constructed from mononuclear or polynuclear silver building blocks exhibit three typical structure features from 1-D to 3-D frameworks. These compounds favour a slow release of Ag⁺ ions leading to excellent and long-term antimicrobial activities, which is distinguished by their different topological structures, towards both Gram-negative bacteria, Escherichia coli (E. coli) and Gram-positive bacteria, Staphylococcus aureus (S. aureus). In addition, these compounds show good thermal stability and light stability under UV-vis and visible light, which are important characteristics for their further application in antibacterial agents.