48 research outputs found

    Insights into the strong in-vitro anticancer effects for bis(triphenylphosphane)iminium compounds having perchlorate, tetrafluoridoborate and bis(chlorido)argentate anions

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    Three new compounds containing the bis(triphenylphosphane)iminium cation (PPN+) with ClO4−, BF4− and [AgCl2]− as counter anions have been synthesized and structurally characterized. The two derivatives with ClO4− and BF4− were found to be isostructural by single crystal X-ray diffraction. Interestingly, the three compounds show extremely potent antiproliferative effects against the human cancer cell line SKOV3. To gain insights into the possible mechanisms of biological action, several intracellular targets have been considered. Thus, DNA binding has been evaluated, as well as the effects of the compounds on the mitochondrial function. Furthermore, the compounds have been tested as possible inhibitors of the seleno-enzyme thioredoxin reductase

    On the influence of Si:Al ratio and hierarchical porosity of FAU zeolites in solid acid catalysed esterification pretreatment of bio-oil

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    A family of faujasite (FAU) zeolites with different Si:Al ratio, and/or hierarchical porosity introduced via post-synthetic alkaline desilication treatment, have been evaluated as solid acid catalysts for esterification pretreatments of pyrolysis bio-oil components. Acetic acid esterification with aliphatic and aromatic alcohols including methanol, anisyl alcohol, benzyl alcohol, p-cresol and n-butanol was first selected as a model reaction to identify the optimum zeolite properties. Materials were fully characterised using N2 porosimetry, ICP, XRD, XPS, FT-IR, pyridine adsorption, NH3 TPD, In-situ ATR and inverse gas chromatography (IGC). IGC demonstrates that the surface polarity and hence hydrophobicity of FAU decreases with increased Si:Al ratio. Despite possessing a higher acid site loading and acetic acid adsorption capacity, high Al-content FAU possess weaker acidity than more siliceous catalysts. Esterification activity increases with acid strength and decreasing surface polarity following the order FAU30>FAU6>FAU2.6. The introduction of mesoporosity through synthesis of a hierarchical HFAU30 material further enhances esterification activity through improved acid site accessibility and hydrophobicity. Methanol was the most reactive alcohol for esterification, and evaluated with HFAU30 for the pretreatment of a real pyrolysis bio-oil, reducing the acid content by 76% under mild conditions

    Synthesis, characterization and antibacterial activity studies of new 2‑pyrral‑L‑amino acid Schif base palladium (II) complexes.

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    Three new 2-pyrral amino acid Schif base palladium (II) complexes were synthesized, characterized and their activity against six bacterial species was investigated. The ligands: Potassium 2-pyrrolidine-L-methioninate (L1), Potassium 2-pyrrolidine-L-histidinate (L2) and Potassium 2-pyrrolidine-L-tryptophanate (L3) were synthesized and reacted with dichloro(1,5- cyclooctadiene)palladium(II) to form new palladium (II) complexes C1, C2 and C3, respectively. 1 NMR, FTIR, UV–Vis,elemental analysis and conductivity measurements were used to characterize the products. The antibacterial activities of the compounds were evaluated against Gram-positive Staphylococcus aureus (S. aureus, ATCC 25923), methicillin-resistant Staphylococcus aureus (MRSA, ATCC 33591), Staphylococcus epidermidis (S. epidermidis, ATCC 12228) and Streptococcus pyogenes (S. pyogenes, ATCC 19615) and, gram-negative Pseudomonas aeruginosa (P. aeruginosa, ATCC 27853) and Klebsiella pneumoniae (K. pneumoniae, ATCC 13883) using the agar well difusion assay and microtitre plate serial dilution method. The palladium complexes were active against the selected bacteria with the imidazole ring containing complex C2 and indole heterocyclic ring containing complex C3 showing the highest activity

    A comprehensive examination of physical characteristic of ternary halide perovskites AgXBr3 (X= Ca, Sr, and Ba) towards optoelectronic and photovoltaic applications

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    The present paper investigates and explains a computational study of the physical characteristics of the silver compound AgXBr3 (X = Ca, Ba, and Sr) perovskites. The calculations are determined by WIEN2K code within DFT by considering (GGA) and hybrid functional (HSE) approximations. Optimization of the lattice constants of the three compounds shows a suitable concord with the available theoretical literature. Moreover, the electronic properties indicate that these compounds behave as semiconductors, exhibiting an indirect band gap. Elastic and mechanical characteristics are studied for the first time, indicating the stability of materials under investigation. The optical properties show that these perovskites are promising candidates for photovoltaic and optoelectronic applications due totheir superior absorption coefficient and modest reflectivity. Furthermore, the thermodynamic and thermoelectric attributes suggest that the perovskite materials investigated hold promise for implementation in thermoelectric technology, showcasing a favourable figure of merit at ambient temperature

    Efficient Ni–Mo hydrodesulfurization catalyst prepared through Keggin polyoxometalate

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    NiMo/SiO2 hydrodesulfurization catalyst prepared through the polyoxometalate route using Keggin type phosphomolybdates has high activity in HDS of thiophene at 350–400 °C and 1 bar pressure. The NiMo/SiO2 pre-catalyst retains intact Keggin structure of phosphomolybdic polyoxometalate, which transforms on stream into a NiMo sulfidic active phase. The pre-catalyst also possesses Brønsted and Lewis acidity, which is lost during the HDS reaction. This catalyst undergoes faster sulfidation and shows higher thiophene conversion and higher butene selectivity than conventional industrial NiMo/Al2O3 catalyst with similar Mo loading. The polyoxometalate catalyst preparation route is therefore considered to be a performance enhancement methodology for HDS catalysis

    Synthesis, structure and spectroscopic properties of bis(triphenylphosphane)iminium (chlorido)(cyanido) argentates(I)

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    Four new compounds containing the (chlorido)((2-x))(cyanido)(x)argentate(I) anion (x = 2, 1.63, 1 and 0.5) are reported. Their solid-state structures with the monocation PPN, bis(triphenylphosphane) iminium, are described; in a few cases the products also contain solvent molecules. The compounds have the formula (PPN)(2)[Ag2Cl3(CN)], (PPN)[Ag(CN)Cl](CH2Cl2) and (PPN)[Ag(CN)(1.63)Cl-0.37](hexane)(0.5) and (PPN)[Ag(CN)(2)] (CH2Cl2). Apart from the molecular structures and the synthetic process, also the solid-state luminescence has been studied.In the case of (PPN)(2)[Ag2Cl3(CN)], the silver ions are pseudo-trigonally coordinated, with 2 chloride bridges between the Ag+ ions. The terminal Cl and terminal CN ligands are disordered over two positions, but only a single C-13 NMR signal is observed for the cyanide ligands of this compound. The compound (PPN)[Ag(CN)(2)] serves as a reference compound and contains the linear [Ag(CN)(2)] unit.The compound with CN/Cl = 1.0 shows disorder of the [AgCl(CN)] unit, and also in the compounds with other CN/Cl ratios, disorder among the Cl - and CN - ligands is seen. The Ag+ ion is linearly coordinated by two ligands in these two cases, and for cyanides normal Ag-C bond lengths are observed in both cases (1.97-1.99 angstrom). The [Ag(CN)(2)] anion is linear and uneventful. The PPN cation has normal bond lengths in all 4 compounds and no short contacts with other atoms in the lattice are observed. The luminescence properties of the new compounds were explored as solid powders. Only one of the compounds (compound 2, with x = 1) shows luminescence under excitation. The other three compounds do not show emission when irradiated at 320 nm, 350 nm or 380 nm. (C) 2015 Elsevier B. V. All rights reserved.Metals in Catalysis, Biomimetics & Inorganic Material

    Exo double left right arrow Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

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    The exo double left right arrow endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp(2)-sp(2) single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV-Vis., optical energy gap, FTIR, and H-1-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric-derivative thermogravimetric analysis, indicating its stability up to 95 degrees C

    Sol-Gel Synthesized Nickel-Oxide-Based Fabrication of Arsenic (As<sup>3+</sup>) Sensor

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    Heavy metal ions can have a negative impact on human health when they are present in the environment and diet. In order to enhance healthcare globally, simple, dependable, sensitive, rapid, and accurate technologies for their detection must be created. Herein, we report a sol-gel preparation of nickel oxide (NiO) nanoparticles. The prepared NiO nanoparticles are extensively characterized by PXRD, SEM, and EDS approaches. The obtained SEM results showed that NiO has a nanosphere-shaped surface morphology. The surface area of a gold electrode (Au) was fabricated with NiO nanoparticles via the drop-casting method. The fabricated electrode with NiO nanoparticles (NiO/Au) was applied as an arsenic sensor. The NiO/Au exhibits decent sensitivity of 3.10 µA/ppb and a limit of detection of 1.94 ppb. The NiO/Au also shows good sensing performance for arsenic detection, which includes good stability, repeatability, and selectivity. So far, this is the first report which adopted two electrochemical techniques (cyclic voltammetry and linear sweep voltammetry) for the detection of arsenic using NiO/Au
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