2D Bipyrimidine silver(I) nitrate: Synthesis, X-ray structure, solution chemistry and anti-microbial activit

Synthesis and X-ray single crystal structure analysis of the compound {[Ag₂(μ₂-bpym)(μ-O-NO₃)₂]}_n, (1), (where bpym = 2,2′-bipyrimidine) are presented. Compound (1) has a (6,3)-2D honeycomb structure with a tetrahedral coordination geometry around the Ag(I) ion. In contrary to the solid state structural investigation, ESI-MS for (1) in solution shows a strong peak at m/z 423.0269 which indicates that the [Ag(bpym)₂]⁺ cation is dominating instead of [Ag₂(bpym)]²⁺. The anti-microbial activity of (1) was screened against 15 multi-drug resistant bacteria in comparison to silver(I) sulphadiazine and it showed a high activity against Burkholderia mallei which causes glanders; with a MIC value of 4 μg/ml

New Triazoloquinoxaline Ligand and its Polymeric 1D Silver(I) complex Synthesis, Structure, and Antimicrobial activity

The organic ligand 4-Benzyl-1-(N,N-dimethylamino)-[1,2,4]triazolo[4,3a]quinoxaline 1 (L) and its polymeric silver(I) complex, [Ag2L(NO3)2]n (2), have been synthesized and characterized. The organic ligand 1 crystallizes in the triclinic space group P¯1. The unit cell contains two parallel-stacked molecules. The complex [Ag2L(NO3)2]n (2) crystallizes in the monoclinic space group P21/n. The structure contains two different silver(I) ions. Ag(2) is coordinated by three oxygens (involving two nitrate groups) and to a nitrogen of the triazole ring of 1. These ligands form a strongly distorted tetrahedral, nearly planar coordination sphere. Ag(1) has an approximately tetrahedral geometry. It is bonded to one oxygen of a nitrate anion and a nitrogen of two different L; this aspect giving rise to an infinite chain structure. A final bond to Ag(1) involves the carbon of a phenyl group. It is more weakly bonded to the phenyl carbons on either side of this, so that the Ag(1)-phenyl bonding has aspects of an Ag-allyl bond. Ag(1) and Ag(2) participate in bonding to a common nitrate anion and alternate, the two distinct modes of bridging between them lead to a zig-zag chain structure. In addition to spectroscopic studies, the biological activities of the ligand and of the complex were scanned over a wide range of Gram positive and Gram negative flesh- and bone-eating bacteria. The results are discussed in comparison with well-known antibiotics

Induction of sporulation and antibacterial activity in the aerial mycelium negative mutants of Streptomyces nasri

Egyptian Journal of Biology Vol.3 2001: 23-3

Protective effect of squilla chitosan–silver nanoparticles for Dicentrarchus labrax larvae infected with Vibrio anguillarum

Abstract Antimicrobial nanoparticle therapy was proposed as an alternative strategy to reduce the use of antibiotics in larval-rearing systems. Antibacterial potential of the prepared squilla chitosan–silver nanoparticles and its protective effect on Dicentrarchus labrax (sea bass) larvae in the early stages were studied against Vibrio angularium. Different concentrations of squilla chitosan (Csq) and squilla chitosan–silver nanoparticles (Csq–AgNps) (1, 2, 5, 10, and 20 %) were, in vitro, tested against V.anguillarum and expressed as a role of Log10 mean. Sea bass larvae were treated using: 10 % Csq and 5 % Csq–AgNps as effective inhibitory concentrations against the pathogen either encapsulated during the feeding regime or added directly to the model system via the water from the onset of 4 weeks. The long-term administration of Csq–AgNps through enriched food for both non-infected and infected systems had survival % of 74.5 ± 1.5 and 72.5 ± 2.5, respectively. Larval clinical observations using Csq–AgNps were studied compared with the two controls. The current study found that 5 % encapsulated Csq–AgNps was enough to suppress infection and considered as an alternative to antibiotics in controlling virulent fish pathogens

New silver(I) compounds and their use in pharmaceutical compositions for the treatment, prophylaxis and prevention of infections

The present invention provides new Ag(I) complexes with derivatives of nicotinic acid, nicotinamide and related pyridine ligands, and pharmaceutical compositions comprising such Ag(I) complexes for use in the treatment, prophylaxis and prevention of infections. The invention further provides a solvent free method for the synthesis of Ag(I) complexes containing substituted pyridines, pyrazines and pyrimidines as ligands

New silver(I) compounds and their use in pharmaceutical compositions for the treatment, prophylaxis and prevention of infections

The present invention provides new Ag(I) complexes with derivatives of nicotinic acid, nicotinamide and related pyridine ligands, and pharmaceutical compositions comprising such Ag(I) complexes for use in the treatment, prophylaxis and prevention of infections. The invention further provides a solvent free method for the synthesis of Ag(I) complexes containing substituted pyridines, pyrazines and pyrimidines as ligands

Synthesis, Crystal Structure, Quantum Chemical Calculations, DNA Interactions, and Antimicrobial Activity of [Ag(2-amino-3-methylpyridine)2]NO3 and [Ag(pyridine-2-carboxaldoxime)NO3]

[Ag(2-amino-3-methylpyridine)2]NO3 (1) and [Ag(pyridine-2-carboxaldoxime)NO3] (2) were prepared from corresponding ligands and AgNO3 in water/ethanol solutions, and the products were characterized by IR, elemental analysis, NMR, and TGA. The X-ray crystal structures of the two compounds show that the geometry around the silver(I) ion is bent for complex 1 with nitrate as an anion and trigonal planar for complex 2 with nitrate coordinated. ESI-MS results of solutions of 2 indicate the independent existence in solution of the [Ag(pyridine-2-carboxaldoxime)]+ ion. The geometries of the complexes are well described by DFT calculations using the ZORA relativistic approach. The compounds were tested against 14 different clinically isolated and four ATCC standard bacteria and yeasts and also compared with 17 commonly used antibiotics. Both 1 and 2 exhibited considerable activity against S. lutea, M. lutea, and S. aureus and against the yeast Candida albicans, while 2-amino-3-methylpyridine is slightly active and pyridine-2-carboxaldoxime shows no antimicrobial activity. In addition, the interaction of these metal complexes with DNA was investigated. Both 1 and 2 bind to DNA and reduce its electrophoretic mobility with different patterns of migration, while the ligands themselves induce no change

Effects of Different Substituents on the Crystal Structures and Antimicrobial Activities of Six Ag(I) Quinoline Compounds

The syntheses and single crystal X-ray structures of [Ag­(5-nitroquinoline)₂]­NO₃ (<b>1</b>), [Ag­(8-nitroquinoline)₂]­NO₃·H₂O (<b>2</b>), [Ag­(6-methoxy-8-nitroquinoline)­(NO₃)]_<i>n</i> (<b>3</b>), [Ag­(3-quinolinecarbonitrile)­(NO₃)]_<i>n</i> (<b>4</b>), [Ag­(3-quinolinecarbonitrile)₂]­NO₃ (<b>5</b>), and [Ag­(6-quinolinecarboxylic acid)₂]­NO₃ (<b>6</b>) are described. As an alternative to solution chemistry, solid-state grinding could be used to prepare compounds <b>1</b> and <b>3</b>, but the preparation of <b>4</b> and <b>5</b> in this way failed. The Ag­(I) ions in the monomeric compounds <b>1</b>, <b>2</b>, <b>5</b>, and <b>6</b> are coordinated to two ligands via the nitrogen atoms of the quinoline rings, thereby forming a distorted linear coordination geometry with Ag–N bond distances of 2.142(2)–2.336(2) Å and N–Ag–N bond angles of 163.62(13)°–172.25(13)°. The 1D coordination polymers <b>3</b> and <b>4</b> contain Ag­(I) centers coordinating one ligand and two bridging nitrate groups, thereby forming a distorted trigonal planar coordination geometry with Ag–N bond distances of 2.2700(14) and 2.224(5) Å, Ag–O bond distances of 2.261(4)–2.536(5) Å, and N–Ag–O bond angles of 115.23(5)°–155.56(5)°. Hirshfeld surface analyses of compounds <b>1</b>–<b>6</b> are presented as <i>d</i>_norm and curvedness maps. The <i>d</i>_norm maps show different interaction sites around the Ag­(I) ions, i.e., Ag···Ag interactions and possible O–H···O, C–H···O, C–H···N, and C–H···C hydrogen bonds. Curvedness maps are a good way of visualizing π–π stacking interactions between molecules. The antimicrobial activities of compounds <b>1</b>, <b>2</b>, and <b>6</b> were screened against 15 different multidrug-resistant strains of bacteria isolated from diabetic foot ulcers and compared to the antimicrobial activities of the clinically used silver sulfadiazine (SS). Compound <b>2</b> showed activity similar to SS against this set of test organisms, being active against all strains and having slightly better average silver efficiency than SS (5 vs 6 μg Ag/mL). Against the standard nonresistant bacterial strains of Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, and Streptococcus pyogenes, compound <b>1</b> performed better than silver nitrate, with an average MIC of 6 μg Ag/mL versus 18 μg Ag/mL for the reference AgNO₃. Electrospray ionization mass spectrometry (ESI-MS) analyses of compounds <b>3</b> and <b>6</b> in DMSO/MeOH confirm the two-coordinated Ag⁺ complexes in solution, and the results of the ¹H NMR titrations of DMSO solutions of 5-nitroquinoline and 8-nitroquinoline with AgNO₃ in DMSO suggest that 5-nitroquinoline is more strongly coordinated to the silver ion

Effects of Different Substituents on the Crystal Structures and Antimicrobial Activities of Six Ag(I) Quinoline Compounds

The syntheses and single crystal X-ray structures of [Ag­(5-nitroquinoline)₂]­NO₃ (<b>1</b>), [Ag­(8-nitroquinoline)₂]­NO₃·H₂O (<b>2</b>), [Ag­(6-methoxy-8-nitroquinoline)­(NO₃)]_<i>n</i> (<b>3</b>), [Ag­(3-quinolinecarbonitrile)­(NO₃)]_<i>n</i> (<b>4</b>), [Ag­(3-quinolinecarbonitrile)₂]­NO₃ (<b>5</b>), and [Ag­(6-quinolinecarboxylic acid)₂]­NO₃ (<b>6</b>) are described. As an alternative to solution chemistry, solid-state grinding could be used to prepare compounds <b>1</b> and <b>3</b>, but the preparation of <b>4</b> and <b>5</b> in this way failed. The Ag­(I) ions in the monomeric compounds <b>1</b>, <b>2</b>, <b>5</b>, and <b>6</b> are coordinated to two ligands via the nitrogen atoms of the quinoline rings, thereby forming a distorted linear coordination geometry with Ag–N bond distances of 2.142(2)–2.336(2) Å and N–Ag–N bond angles of 163.62(13)°–172.25(13)°. The 1D coordination polymers <b>3</b> and <b>4</b> contain Ag­(I) centers coordinating one ligand and two bridging nitrate groups, thereby forming a distorted trigonal planar coordination geometry with Ag–N bond distances of 2.2700(14) and 2.224(5) Å, Ag–O bond distances of 2.261(4)–2.536(5) Å, and N–Ag–O bond angles of 115.23(5)°–155.56(5)°. Hirshfeld surface analyses of compounds <b>1</b>–<b>6</b> are presented as <i>d</i>_norm and curvedness maps. The <i>d</i>_norm maps show different interaction sites around the Ag­(I) ions, i.e., Ag···Ag interactions and possible O–H···O, C–H···O, C–H···N, and C–H···C hydrogen bonds. Curvedness maps are a good way of visualizing π–π stacking interactions between molecules. The antimicrobial activities of compounds <b>1</b>, <b>2</b>, and <b>6</b> were screened against 15 different multidrug-resistant strains of bacteria isolated from diabetic foot ulcers and compared to the antimicrobial activities of the clinically used silver sulfadiazine (SS). Compound <b>2</b> showed activity similar to SS against this set of test organisms, being active against all strains and having slightly better average silver efficiency than SS (5 vs 6 μg Ag/mL). Against the standard nonresistant bacterial strains of Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, and Streptococcus pyogenes, compound <b>1</b> performed better than silver nitrate, with an average MIC of 6 μg Ag/mL versus 18 μg Ag/mL for the reference AgNO₃. Electrospray ionization mass spectrometry (ESI-MS) analyses of compounds <b>3</b> and <b>6</b> in DMSO/MeOH confirm the two-coordinated Ag⁺ complexes in solution, and the results of the ¹H NMR titrations of DMSO solutions of 5-nitroquinoline and 8-nitroquinoline with AgNO₃ in DMSO suggest that 5-nitroquinoline is more strongly coordinated to the silver ion