Antimicrobial Activity of Water-Soluble Silver Complexes Bearing C-Scorpionate Ligands

The novel hydrosoluble silver coordination polymer [Ag(NO )(μ-1κ ;2 ', ″-TPM )] ( ) (TPM = tris(1 -pyrazol-1-yl)ethanol) was obtained and characterized. While single crystal X-ray diffraction analysis of compound disclosed an infinite 1D helical chain structure in the solid state, NMR analysis in polar solvents confirmed the mononuclear nature of compound in solution. Compound and the analogue [Ag(μ-1κ ;2 ', ″-TPMS)] ( ) (TPMS = tris(1 -pyrazol-1-yl)methane sulfonate) were evaluated with regard to their antimicrobial activities towards the Gram-negative , , and , the Gram-positive , and the fungal species and . Compound exhibited minimal inhibitory concentration (MIC) values ranging from 2 to 7.7 µg/mL towards the tested Gram-negative bacteria, 18 µg/mL towards the Gram-positive , and 15 and 31 µg/mL towards and , respectively. Compound was less effective towards the tested bacteria, with MIC values ranging from 15 to 19.6 µg/mL towards the Gram-negative bacteria and 51 µg/mL towards ; however, it was more effective against and , with MIC values of about 6 µg/mL towards these fungal species. The toxicity of compounds and was assessed by evaluating the survival of the model organism to concentrations of up to 100 µg/mL. The value of 50% lethality (LD ) could only be estimated as 73.2 µg/mL for compound at 72 h, otherwise LD was >100 µg/mL for both compounds and . These results indicate compounds and as novel silver complexes with interesting antimicrobial properties towards bacterial and fungal pathogens.