Silver(I) complexes with 2,6-diacetylpyridine- bis (benzoylhydrazones): Antifungal activity and interaction with DNA

Silver(I) complexes containing bioactive salicylic acid derivatives: Synthesis, characterization, antibacterial activity, and their underlying mechanism

Recognizing that silver-metallodrugs are a potential source of novel anti-infective therapeutic agents, this work adopts the complexation of biologically active salicylic acid derivatives with inherently antibacterial silver(I) ions as a strategy for developing new antibacterial agents. The synthesized silver(I) complexes were characterized by elemental analysis, spectroscopy, and X-ray diffraction analysis. The crystallographic results indicate that the silver(I) ion in complexes [Ag(imH)2](SalH) (1) and [Ag(imH)2](DiSalH)·H2O (2) only coordinates with the imidazole nitrogen atom, while the 4-aminosalicylic acid in complex [Ag(imH)2(AmSalH)]·H2O (3) additionally coordinate with the silver(I) ion through the amino nitrogen atom. Salicylic acid molecules play an important role in the construction of the three-dimensional network structure through weak interactions. In addition, thermogravimetric analysis, stability, and silver(I) ion release experiments indicate that these complexes have good stability and slow ion release rates. Cell toxicity and antibacterial tests were conducted on selected cell lines and microorganisms using complexes 1-3, and compared with silver(I) salts, organic ligands, and antibiotic. All complexes exhibit better biocompatibility and certain anti-tumor selectivity than silver(I) salts. From the perspective of microbial toxicity, complexes 1-3 all have significant inhibitory effects on three bacteria strains, with complex 1 having the strongest antibacterial activity, exhibiting 4-6 times higher activity against certain strains than AgNO3 and chloramphenicol. Mechanism studies have shown that cell wall perforation and imbalance of intracellular ROS levels may be possible reasons for silver(I) complexes induced bacterial cell death. The biofilm removal experiment further proves the potential use of silver(I) complexes 1-3 in the treatment of bacterial infections.

Organotin(IV) complexes derived from 2,6-diacetylpyridine bis(2-hydroxybenzoylhydrazone) as prospective anti-proliferative agents: Synthesis, characterization, structures and in vitro anticancer activity

Six organotin(IV) complexes, viz., [Me2Sn(L)] (1), [n-Bu2Sn(L)] (2), [n-Oct2Sn(L)] (3), [Bz2Sn(L)]·0.5C7H8 (4), [n-BuSn(L)Cl] (5), and [PhSn(L)Cl] (6), were synthesized using a 2,6-diacetylpyridine bis(2-hydroxybenzoylhydrazone), H2L. Compounds were characterized by Fourier transform infrared (FT-IR), High-resolution mass spectrometry (HRMS), and solutions Fourier transform nuclear magnetic resonance (FT-NMR) spectroscopies. The structures 1-6 were established by single-crystal X-ray diffraction (SC-XRD) analysis. Diffraction results evidenced that complexes 1-6 were seven-coordinated mononuclear species with the equatorial plane comprising the pentagonal N3O2 chelate ring of the doubly deprotonated L and two axial ligands, either R (R = Me, n-Bu, n-Oct, Bz) or R (n-Bu or Ph) and Cl ligands. Additionally, the photophysical properties were examined due to the enhanced conjugation and rigidity of the molecules while thermogravimetric analysis was carried out to evaluate the thermal stabilities of compounds. The anti-proliferative activity of the complexes 1-6 was tested against prostate cancer cells (DU-145) and normal human embryonic kidney cells (HEK-293). Among the compounds, dibutyltin compound 2 exhibited increased anti-proliferative activity, with an IC50 value of 6.16 ± 1.56 μM. The investigation of its mechanism of action involves using AO/EB (acridine orange/ethidium bromide) and ROS (reactive oxygen species) generation assays. This likely detects apoptotic morphological alterations in the nucleus of the cells, with ROS generation ultimately leading to apoptosis and cell death. The superior activity of 2 may be attributed to the C···H contacts and respective higher de outside and di inside distances from the Hirshfeld surface. Thus, these compounds could be a promising alternative to classical chemotherapy agents.

TEMPO coordination and reactivity in group 6; pseudo-pentagonal planar (η2-TEMPO)2CrX (X = Cl, TEMPO)

The exposure of CrCl₂(THF)₂ to 1 equiv. of TEMPO and 1 equiv. [TEMPO]Na afforded (η²-O,N-TEMPO)₂CrCl (1, 67%); addition of [TEMPO]Na to 1 yielded (η²-O,N-TEMPO)₂Cr(TEMPO) (2). Both 1 and 2 exhibit pseudo-pentagonal planar (PPP) geometry, instead of myriad alternatives. Calculations and spectral studies suggest the solid-state geometry persists in solution.

Silver(i) complexes with 2-acetylpyridinebenzoylhydrazones exhibit antimicrobial effects against yeast and filamentous fungi

2-Acetylpyridinebenzoylhydrazones and their silver(i) complexes show antimicrobial effects and deserve to be investigated as antifungal drug candidates.