Antibacterial silver and gold complexes of imidazole and 1,2,4-triazole derived N-heterocyclic carbenes

Abstract

A series of gold(I) (4a – 4h, 5a – 5b) and silver(I) (3a – 3h) complexes of 1,2,4-triazolylidene and imidazolylidene based N-heterocyclic carbene ligands were prepared and the antibacterial activities...

Anionic N-Heterocyclic Carbene Gold(I) Complexes from Sydnones as a Precarbenic Unit: A Comprehensive Study of the Au–C sp2 Bond Stability Compared to Its “Relative” Imidazole

“…Next, DFT methods were employed to identify correlations between experimental stability or catalytical activity and electronical properties of the complexes. The optimized geometries of the calculated complexes are in agreement with theoretical and experimental ,, results of closely related compounds, and the computational methods were proven to perform well in these systems. , …”

Silver Organometallics that are Highly Potent Thioredoxin and Glutathione Reductase Inhibitors: Exploring the Correlations of Solution Chemistry with the Strong Antibacterial Effects

“…In contrast to the promising results with the Gram-negative strains, a poor antibacterial activity against the two Gram-positive strains was determined for all silver complexes. Such observations are in line with previous reports, where Gram-positive bacteria have been shown to be less sensitive toward silver salts and their complexes. ,,, …”

“…As the biological effects of silver are attributed to the release of Ag + ions, the identification of robustly coordinated ligands is crucial for silver metallodrug development, in order to enhance bioavailability, improve targeting, and optimize binding to molecular drug targets. N-heterocyclic carbenes (NHCs) are ligands that form highly stable organometallic complexes with many transition metals and are therefore nowadays widely employed in bioinorganic medicinal chemistry. , Youngs and co-workers have pioneered the field of antibacterial silver NHC complexes and confirmed the antibacterial efficacy of this type of complexes in vitro and in vivo (see Figure for 1 as a representative example). − The rapidly increasing number of reported silver NHC complexes with antibacterial activity confirms the recognized potential of such complexes for drug discovery. − For example, complex 2 , developed by Tacke and colleagues, represents a promising example of a silver drug candidate, for which detailed proteomic responses have been recorded, and the inhibition of bacterial thioredoxin reductase was demonstrated. ,− Notably, silver NHC complexes have also been described as antiviral and cytotoxic agents. − …”

“…Such observations are in line with previous reports, where Gram-positive bacteria have been shown to be less sensitive toward silver salts and their complexes. 11,26,51,52 Effect of Growth Media on the Antibacterial Activity. The importance of the culture medium used in antibacterial assays has been pointed out for antibiotics and in particular for silver.…”

Synthesis and biological evaluation of ruthenium complexes bearing the 1,2,4-triazole group as potential membrane-targeting antibacterial agents towards Staphylococcus aureus

“…Complexes of gold and 1,2,4-triazole derivatives, as reported, have shown effective antimicrobial activity against Gram-positive bacteria. 32 Additionally, the complexation of 1,2,4-triazole fungicides with Cu( ii ) exhibited superior activity and lower toxicity than their ligands. 33 Although complexes of transition metals and 1,2,4-triazole derivatives have shown potential value in the field of antimicrobials, studies on the antibacterial properties of these complexes need to be promoted, and studies on the antibacterial activity of 1,2,4-triazole with ruthenium are scarce.…”