Structural Characterization, Antimicrobial Activity and BSA/DNA Binding Affinity of New Silver(I) Complexes with Thianthrene and 1,8-Naphthyridine

Abstract

Three new silver(I) complexes [Ag(NO3)(tia)(H2O)]n (Ag1), [Ag(CF3SO3)(1,8-naph)]n (Ag2) and [Ag2(1,8-naph)2(H2O)1.2](PF6)2 (Ag3), where tia is thianthrene and 1,8-naph is 1,8-naphthyridine, were synthesized and structurally characterized by different spectroscopic and electrochemical methods and their crystal structures were determined by single-crystal X-ray diffraction analysis. Their antimicrobial potential was evaluated against four bacterial and three Candida species, and the obtained results revealed that these complexes showed significant activity toward the Gram-positive Staphylococcus aureus, Gram-negative Pseudomonas aeruginosa and the investigated Candida species with minimal inhibitory concentration (MIC) values in the range 1.56–7.81 μg/mL. On the other hand, tia and 1,8-naph ligands were not active against the investigated strains, suggesting that their complexation with Ag(I) ion results in the formation of antimicrobial compounds. Moreover, low toxicity of the complexes was detected by in vivo model Caenorhabditis elegans. The interaction of the complexes with calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) was studied to evaluate their binding affinity towards these biomolecules for possible insights into the mode of antimicrobial activity. The binding affinity of Ag1–3 to BSA was higher than that for DNA, indicating that proteins could be more favorable binding sites for these complexes in comparison to the nucleic acids.

Copper(ii) and silver(i) complexes with dimethyl 6-(pyrazine-2-yl)pyridine-3,4-dicarboxylate (py-2pz): the influence of the metal ion on the antimicrobial potential of the complex

“…2B). 37,[57][58][59] When the cyclic voltammogram was recorded in the cathodic direction, two reduction peaks I c,1 and I c,2 were observed, which can be attributed to the Ag(II) / Ag(I) and Ag(I) / Ag(0) processes, respectively (Fig. 2B), in accordance with the other silver(I) complexes which electrochemical behavior was previously reported.…”

“…2B), in accordance with the other silver(I) complexes which electrochemical behavior was previously reported. 37,[57][58][59] Computational results…”

Silver(i) complexes bearing heterocyclic thioamide ligands with NH2 and CF3 substituents: effect of ligand group substitution on antibacterial and anticancer properties

“…Considering the high biological efficacy of 1-3, we investigated their potential to interact with this biomolecule 69,70 and their mode of interaction. 43,44,71 The interaction of 1-3 with CT-DNA was initially studied by UV-Vis absorption spectroscopy. In particular, we followed the changes in specific UV absorption bands of the three complexes in DMSO solutions, upon addition of increasing amounts of CT-DNA.…”

Digold(I) Thianthrenyl Complexes. Effect of Diphosphine Ligands on Molecular Structures in the Solid State and in Solution

“…Thus, we attempted the synthesis of digold­(I) complexes with polyaromatic ligands in order to stabilize the U-shaped structure by the π–π interaction of the two aromatic ligands. Thianthrene has been reported to form complexes with Ag­(I), Au­(I), and Pd­(II) as neutral S-ligands. − Pd complexes containing a phosphine ligand bearing a thianthrenyl substituent have been reported to form a cyclic compound with a Pd–S bond . An Fe complex with η 6 -coordinated thianthrene has also been prepared and reported to show electrochemical responses from the ligand and Fe centers .…”