Silver(I) complexes with phenolic Schiff bases: Synthesis, anti-bacterial evaluation and interaction with biomolecules

Novel Ag(I) complexes (2a–2c) with phenolic Schiff bases were synthesized using 4,6-di-tert-butyl-3-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)benzene-1,2-diol (1a), 4,6-di-tert-butyl-3-(((4-mercaptophe­nyl­)­imino)­methyl)benzene-1,2-diol (1b), and 4,6-di-tert-butyl-3-(((3-mercaptophenyl)imino)methyl)­benzene-1,2-diol (1c). They were examined by elemental analysis, FT-IR, UV-Vis, 1H-NMR spectroscopy, XRD, cyclic voltammetry, conductivity measurements, and biological methods. The complexes are characterized by distorted geometry of the coordination cores AgN2S2 (2c), AgNS (2b) and AgS2 (2a). These stable complexes were not typified by the intramolecular redox reaction in organic solvents resulting in the formation of silver nanoparticles (AgNPs). Antibacterial activity of 1a–1c and 2a–2c was evaluated in comparison with AgNPs and commonly used antibiotics. All the complexes were more active than the ligands against the bacteria tested (14), but they were less active than AgNPs and commonly used antibiotics. Both 1a–1c and their complexes 2a–2c exhibited the capability for the bovine heart Fe(III)-Cyt c reduction. The ligands 1b and 1c were characterized by the highest reduction rate among the compounds under study, and they showed a higher reducing ability (determined by cyclic voltammetry) as compared with that of their Ag(I) complexes 2b and 2c

Cyclic voltammetry as a sensitive method for in situ probing of chemical transformations in quantum dots

The application of electrochemical methods for the characterization of colloidal quantum dots (QDs) attracts considerable attention as these methods may allow for monitoring of some crucial parameters, such as energetic levels of conduction and valence bands as well as surface traps and ligands under real conditions of colloidal solution. In the present work we extend the applications of cyclic voltammetry (CV) to in situ monitoring of degradation processes of water-soluble CdTe QDs. This degradation occurs under lowering of pH to the values around 5, i.e. under conditions relevant to bioimaging applications of these QDs, and is accompanied by pronounced changes of their photoluminescence. Observed correlations between characteristic features of CV diagrams and the fluorescence spectra allowed us to propose mechanisms responsible for evolution of the photoluminescence properties as well as degradation pathway of CdTe QDs at low pH

Synthesis, Characterization and Biological Activity of Hydrazones and Their Copper(II) Complexes

The fundamental importance of copper as a redox-active metal essential to the functioning of several metabolic enzymes provides a wide range of its biological activity pathways. Copper(II) coordination compounds are known to exhibit potent antiproliferative, antibacterial, nuclease, anti-inflammatory and antimycobacterial activities. Hydrazones are organic ligands commonly used for complexation with copper(II) that possess antibacterial, antiviral and antifungal properties. Copper–ligand interaction might facilitate charge delocalization and increase net hydrophobicity of the system, resulting in its enhanced pharmacological activity. Coordination compounds of Cu(II) with 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde derived hydrazone, nitrofurantoin and ftivazide have been synthesized, characterized by means of elemental and XRD analysis, FT-IR, UV-Vis and NMR spectroscopy and tested for antibacterial activity in vitro on Gram-positive and Gram-negative bacteria

Synthesis, Characterization and Biological Activity of Hydrazones and Their Copper(II) Complexes

The fundamental importance of copper as a redox-active metal essential to the functioning of several metabolic enzymes provides a wide range of its biological activity pathways. Copper(II) coordination compounds are known to exhibit potent antiproliferative, antibacterial, nuclease, anti-inflammatory and antimycobacterial activities. Hydrazones are organic ligands commonly used for complexation with copper(II) that possess antibacterial, antiviral and antifungal properties. Copper–ligand interaction might facilitate charge delocalization and increase net hydrophobicity of the system, resulting in its enhanced pharmacological activity. Coordination compounds of Cu(II) with 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde derived hydrazone, nitrofurantoin and ftivazide have been synthesized, characterized by means of elemental and XRD analysis, FT-IR, UV-Vis and NMR spectroscopy and tested for antibacterial activity in vitro on Gram-positive and Gram-negative bacteria

Phase Formation, Microstructure, and Mechanical Properties of Ni-Cu Bimetallic Materials Produced by Electron Beam Additive Manufacturing

The paper presents the results of applying wire-feed electron beam additive manufacturing technology to produce bimetallic samples of CuCr1 copper alloy and Udimet 500 nickel-based superalloy. Different printing strategies were used to obtain samples with a defect-free structure and high mechanical properties in the transition zone, not inferior to the strength of copper alloy. Two types of samples were fabricated with a sharp and smooth CuCr1/Udimet 500 interface. The printing strategies of type I and II samples differed in the combination and arrangement of nickel and copper alloy layers. Structural studies in the transition zone revealed mechanical mixtures of initial copper and nickel alloy components and solid solutions based on nickel, copper, and chromium. Despite the presence of defects and structural heterogeneities in the experimental samples, the mechanical properties of the main components are at a high level, corresponding to the typical properties of copper and nickel alloys. The strength of the transition zone in type II samples is between the strength of Udimet 500 and CuCr1