Abstract
In the last two decades, a tremendous amount of attention has been directed towards the design of antibacterial silver(I)-based materials, including coordination polymers (CPs) built up with a great variety of oxygen and nitrogen-containing ligands. Herein, a family of six new silver(I)-based CPs, having the general stoechiometric formula [Ag(H2DMPMB)(X)] (X = NO3, 1; CF3CO2, 2; CF3SO3, 3; BF4, 4; ClO4, 5; and PF6, 6) and incorporating the flexible ditopic pyrazolyl-type ligand 4,4′-bis((3,5-dimethyl-1H-pyrazol-4-yl)methyl)biphenyl (H2DMPMB), has been prepared by the chemical precipitation method involving the reaction of silver(I) salts with H2DMPMB in the 1:1 molar ratio, in alcohols, or acetonitrile at room temperature for two-hours. The new silver(I)-based polymeric materials were characterized by means of Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), and thermogravimetric analysis (TGA), allowing for the proposition that their structures comprise one-dimensional chains, with the silver(I) ions mostly assuming a T-shapped stereochemistry completed by the exo-bidentate ligands and counter-anions. The obtained silver(I) CPs showed a remarkable light insensitivity and stability in the air, are insoluble in water and in most common organic solvents, and possess appreciable thermal stabilities spanning the range 250–350 °C. The antibacterial activity of the obtained silver(I) CPs was tested against the Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus) using the Tetrazolium/Formazan test (TTC), by measuring the bacterial viability at different time intervals. The complete reduction of both bacterial strains occurred after 24 h of exposure to all silver(I) CPs, the bacterial viability values for S. aureus reaching 8% for compounds 3, 5, and 6 after only two-hours.
Highlights
The antibacterial activity of the obtained silver(I) Coordination polymers (CPs) was tested against the Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus) using the Tetrazolium/Formazan test (TTC), by measuring the bacterial viability at different time intervals
Coordination polymers (CPs) [1,2,3,4], and the subset of metal-organic frameworks (MOFs) [5,6,7], represent the vast class of inorganic−organic hybrid materials, which are made of metal ions or metal-based clusters and polydentate ligands connected through coordination bonds, which develop into 1-D, 2-D, and 3-D infinite structures
Compounds 1–6, having the general stoechiometric formula [Ag(H2 DMPMB)(X)] (X = NO3, 1; CF3 CO2, 2; CF3 SO3, 3; BF4, 4; ClO4, 5; and PF6, 6), hypothesized with the help of elemental analyses, have been obtained from the room temperature reaction carried out in a 2:1 molar ratio of two equivalents of silver(I) salts and one equivalent of H2 DMPMB, in alcohol for compounds 1–3, 5, and 6, and acetonitrile for compound 4. Their stoechiometry was found to be independent of the amount of silver(I) salts or ligand used in the syntheses, since the 1:1 molar ratio was always obtained, which was observed in other bis(pyrazolyl)-based silver(I) compounds, such as [Ag(H2 BPZ)(X)] (X = NO3, ClO4, BF4, PF6, CH3 SO3, CF3 SO3 ; H2 BPZ = 4,40 -bipyrazole) [54]
Summary
Coordination polymers (CPs) [1,2,3,4], and the subset of metal-organic frameworks (MOFs) [5,6,7], represent the vast class of inorganic−organic hybrid materials, which are made of metal ions or metal-based clusters and polydentate ligands connected through coordination bonds, which develop into 1-D, 2-D, and 3-D infinite structures. CPs and MOFs have gained a special place in fields of industrial, technological, economical, and environmental interest thanks to the great variety of functional properties so far achieved, ranging from gas storage and separation [8] to heterogeneous catalysis [9], luminescence [10], sensing [11], magnetism [12], conductivity [13], and biomedicine [14] For their successful construction, the most typically used organic ligands have been rationally chosen. The present paper is, aimed at synthesizing, through a simple chemical precipitation and high-yielding method, a family of six new silver(I)-based CPs incorporating the flexible ligand and high-yielding method, a family of six new silver(I)-based CPs incorporating the flexible ligand. Two photoluminescent silver nitrate 1D coordination polymers with the bitopic ligand ligand 1,1,2,2-tetra(pyrazol-1-yl)ethane were structurally characterized [63]. (S. aureus) was tested using the Tetrazolium/Formazan test (TTC), by measuring the bacterial viability at different time intervals
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call