Structural studies and investigation on the antifungal activity of silver(I) complexes with 5-nitrofuran-derived hydrazones

Synthesis, characterization, PXRD studies, and theoretical calculation of the effect of gamma irradiation and antimicrobial studies on novel Pd(II), Cu(II), and Cu(I) complexes

The main objective of this study is to synthesize and characterize of a new three complexes of Pd (II), Cu (II), and Cu (I) metal ions with novel ligand ((Z)-2-(phenylamino)-N'-(thiophen-2-ylmethylene)acetohydrazide) H2LB. The structural composition of new compounds was assessed using several analytical techniques including FT-IR, 1H-NMR, electronic spectra, powder X-ray diffraction, and thermal behavior analysis. The Gaussian09 program employed the Density Functional Theory (DFT) approach to optimize the geometry of all synthesized compounds, therefore obtaining the most favorable structures and crucial parameters. An investigation was conducted to examine the impact of γ-irradiation on ligands and complexes. Before and after γ-irradiation, the antimicrobial efficiency was investigated for the activity of ligands and their chelates. The Cu(I) complex demonstrated enhanced antibacterial activity after irradiation, as well as other standard medications such as ampicillin and gentamicin. Similarly, the Cu(I) complex exhibited superior activity against antifungal species relative to the standard drug Nystatin. The docking investigation utilized the target location of the topoisomerase enzyme (2xct) chain A.

Light-Assisted Synthesis of Silver and Gold Nanoparticles by New Benzophenone Derivatives

Benzophenone derivatives were evaluated as new photoinitiators in combination with triethylamine (TEA) and iodonium salt (Iod) for very rapid and efficient formation of metal nanoparticles in an organic solvent, by which silver and gold ions were reduced under light at 419 nm (photoreactor) with an irradiation intensity of 250 microwatts/cm². The new benzophenone derivatives combined with TEA/Iod salt showed good production of metal nanoparticles (Au⁰ and Ag⁰) and a small size of nanoparticles of around 4-13 nm. The photochemical mechanisms for the production of initiating radicals were studied using cyclic voltammetry, where a negative ΔG of around -1.96 eV was obtained, which made the process favorable. The obtained results proved the formation of amine and phenyl radicals, which led to the reduction of gold III chloride or silver ions to the gold and silver NPs. The UV-vis spectroscopy technique was used as a very beneficial tool for the surface plasmon resonance band detection of metal nanoparticles. To sum up the results, we have observed that nanoparticles (NPs) were distributed differently in different photoinitiator systems and the particle size also changed by changing the system of initiation. In comparison to the system alone, not only were the nanoparticles smaller but they were also generated within a shorter period of irradiation time for the system BP\Iod\TEA. Finally, the quenching process of benzophenone fluorescence by the gold and silver nanoparticles was investigated.

Synthesis, Characterization, PXRD Studies, Theoretical Calculation, and Antitumor Potency Studies of a Novel N,O-Multidentate Chelating Ligand and Its Zr(IV), V(IV), Ru(III), and Cd(II) Complexes

A new series of Zr(IV), V(IV), Ru(III), and Cd(II) complexes with the ligand N-((5-hydroxy-4-oxo-4H-pyran-3-yl)methylene)-2-(p-tolylamino)acetohydrazide (H2L) have been prepared. FT-IR, 1H-NMR, electronic spectra, powder X-ray, and thermal behavior methods were applied to elucidate the structural composition of new compounds. Geometry optimization for all synthesized compounds was conducted using the Gaussian09 program via the DFT method, to obtain optimal structures and essential parameters. Moreover, the antibacterial and antitumor activity of the ligand and its complexes were studied, where the Cd(II) complex acquires probably the best antibacterial activity followed by the Ru(III) complex towards bacterial species than others when using ampicillin and gentamicin were used as standard drugs. The complexes exhibited interestingly antitumor potential against the MCF-7 breast cancer cell line. The cytotoxicity of the new complexes has been arranged to follow the order: Ru(III) complex > Cd(II) complex > Zr(IV) complex > V(IV) complex > ligand. Molecular docking was performed on the active site of ribosyltransferase and obtained good results. Structure-based molecular docking is used to identify a potential therapeutic inhibitor for NUDT5.

Searching for novel antimicrobial agents among hydrazide-hydrazones of 4-iodosalicylic acid

Searching for novel antimicrobial agents is up to day topic for many group of researchers due to the fact that each year the number of bacterial strains resistant to currently used medicines increases. Special attention in the scientific literature among various groups of bioactive organic compounds is focused on the antimicrobial activity of hydrazide-hydrazones. Due to this fact presented study is focused on the design, synthesis and in vitro antimicrobial properties of novel hydrazide-hydrazones of 4-iodosalicylic acid. Target compounds were synthesized by the condensation reaction of the hydrazide of 4-iodosalicylic acid with substituted (hetero)aromatic aldehydes. Chemical structure of obtained molecules was confirmed by spectral methods (¹H NMR and ¹³C NMR). Bioactivity screening results revealed interesting antimicrobial properties of tested compounds against reference Gram-positive bacteria and fungi belonging to Candida spp. Especially, hydrazide-hydrazones 3-5 showed very strong or strong bactericidal effect towards some cocci and bacilli (MIC = 7.81-15.62 µg/mL).

Updated Information on Antimicrobial Activity of Hydrazide-Hydrazones

Hydrazide-hydrazones possess a wide spectrum of bioactivity, including antibacterial, antitubercular, antifungal, anticancer, anti-inflammatory, anticonvulsant, antidepressant, antiviral, and antiprotozoal properties. This review is focused on the latest scientific reports regarding antibacterial, antimycobacterial, and antifungal activities of hydrazide-hydrazones published between 2017 and 2021. The molecules and their chemical structures presented in this article are the most active derivatives, with discussed activities having a hydrazide-hydrazone moiety as the main scaffold or as a side chain. Presented information constitute a concise summary, which may be used as a practical guide for further design of new molecules with antimicrobial activity.

Water-soluble silver(i) complexes with N-donor benzimidazole ligands containing an imidazolium core: stability and preliminary biological studies

Herein, we report the synthesis, characterisation and preliminary biological evaluation of two novel silver(i) complexes of type [AgL₂](NO₃)₃ (3 and 4) with ionic N-donor benzimidazoles. The complexes have been synthesized by the reaction of 1.5 equivalents of silver nitrate and N-donor benzimidazoles containing an imidazolium core at the 2-position (1 and 2) in ethanol. The X-ray analysis of 4 shows that it has two free imidazolium cores and the charge is balanced with three nitrate anions. A study by the combination of NMR, IR, LC-MS and elemental analysis techniques also suggests that the complexes have this structure both in the solid-state and solution. The complexes are highly soluble and stable in water. Cytotoxicity evaluation against four cancerous human cells and one non-cancerous human cell revealed that the complexes have no significant anti-growth effect. However, the complexes showed a remarkable antimicrobial effect at normalized minimum inhibitory concentrations (normalized MICs) in the range of 33-268 μM against a panel of microorganisms consisting of Gram-negative and Gram-positive bacteria, and fungi.

Mixed Organometallic-Organic Hybrid Assemblies Based on the Diarsene Complex [Cp2 Mo2 (CO)4 (μ,η2 -As2 )], AgI Salts and N-Donor Organic Molecules

The reaction of the organometallic diarsene complex [Cp2 Mo2 (CO)4 (η2 -As2 )] (1) with Ag[Al{OC(CF3 )3 }4 ] (Ag[TEF]) yielded the AgI monomer [Ag(η2 -1)3 ][TEF] (2). This compound exhibits dynamic behavior in solution, which allows directed selective synthesis of unprecedented organometallic-organic hybrid assemblies upon its reaction with N-donor organic molecules by a stepwise pathway, which is supported by DFT calculations. Accordingly, the reaction of 2 with 2,2'-bipyrimidine (L1) yielded the dicationic molecular compound [{(η2 -1)2 Ag}2 (μ-L1)][TEF]2 (3) or the 1D polymer [{(η2 -1)Ag}(μ-L1)]n [TEF]n (4) depending on the ratio of the reactants. However, its reactions with the pyridine-based linkers 4,4'-bipyridine (L2), 1,2-bis(4-pyridyl)ethylene (L3) and 1,2-bis(4-pyridyl)ethyne (L4) allowed the formation of the 2D polymers [{(η2 -1)Ag}2 (μ-Lx)3 ]n [TEF]2n [Lx=L2 (5), L3 (6), L4 (7), respectively]. Additionally, this concept was extended to step-by-step one-pot reactions of 1, [Ag(CH3 CN)3 ][Al{OC(CF3 )2 (CCl3 )}4 ] ([Ag(CH3 CN)3 ][TEFCl ]) and linkers L2-L4 to produce the 2D polymers [{(η2 -1)Ag}2 (μ,Lx)3 ]n [TEFCl ]2n [Lx=L2 (8), L3 (9), L4 (10), respectively].

Self-Assembly by Tridentate or Bidentate Ligand: Synthesis and Vapor Adsorption Properties of Cu(II), Zn(II), Hg(II) and Cd(II) Complexes Derived from a Bis(pyridylhydrazone) Compound

Four complexes, [Cu₄L₂(OCH₃)₂(CH₃OH)₂]·2H₂O (1), [Zn₂L₂Cl₄]·2H₂O·2CH₃OH (2), [Hg₂L₂Br₄]·4CH₃OH (3), and {[CdL₂Cl₂]·4H₂O·4CH₃OH}_n (4), have been synthesized and characterized from a bis(pyridylhydrazone) ligand (L) with copper(II), zinc(II), mercury(II) or cadmium(II), respectively. Complex 1 exists as a centrosymmetric tetranuclear dimer with L as deprotonated tridentate ligand. Complexes 2 and 3 exist as centrosymmetric metallamacrocycles with L as bidentate ligand. Complex 4 exists as a 1D looped-chain coordination polymer. The thermal stabilities and vapor adsorption properties of the four complexes were investigated as well.

The Potential of the Diarsene Complex [(C5 H5 )2 Mo2 (CO)4 (μ,η2 -As2 )] as a Connector Between Silver Ions

The reaction of the organometallic diarsene complex [Cp₂Mo₂(CO)₄(μ,η²‐As₂)] (B) (Cp = C₅H₅) with Ag[FAl{OC₆F₁₀(C₆F₅)}₃] (Ag[FAl]) and Ag[Al{OC(CF₃)₃}₄] (Ag[TEF]), respectively, yields three unprecedented supramolecular assemblies [(η²‐B)₄Ag₂][FAl]₂ (4), [(μ,η¹:η²‐B)₃(η²‐B)₂Ag₃][TEF]₃ (5) and [(μ,η¹:η²‐B)₄Ag₃][TEF]₃ (6). These products are only composed of the complexes B and Ag^I. Moreover, compounds 5 and 6 are the only supramolecular assemblies featuring B as a linking unit, and the first examples of [Ag^I]₃ units stabilized by organometallic bichelating ligands. According to DFT calculations, complex B coordinates to metal centers through both the As lone pair and the As−As σ‐bond thus showing this unique feature of this diarsene ligand.

Novel Copper Photoredox Catalysts for Polymerization: An In Situ Synthesis of Metal Nanoparticles

The copper II complex (HLCuCl) carrying 2,4 dinitrophenylhydrazone (L) is synthesized and evaluated as a new photoredox catalyst/photoinitiator in combination with triethylamine (TEA) and iodonium salt (Iod) for the radical polymerization of ethylene glycol diacrylate during exposure to visible light using a photoreactor at 419 nm. The copper complex reactivity with TEA/Iod salt/gold chloride showed a good production and stability of gold nanoparticles. Finally, the high performance of Cu (II) complex for radical photopolymerization incorporating gold nanoparticles is provided. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry. Polymer nanocomposites containing gold nanoparticles (Au NPs) in situ photogenerated during the irradiation process were prepared. The formation of Au NPs inside the polymer matrix was through UV-Vis and EDS/SEM analyses.