Adsorption Behavior of Metal Ions by Amidoxime Chelating Resins

In this work, the acrylonitrile (AN) – divinylbenzene (DVB) –methylacrylate (MA) resin was synthesized via suspension polymerization in the presence of toluene as diluent, and benzoylperoxide (BPO) as initiator. The effect of MA, toluene and alkaline treatment on the exchange capacity of the resin were investigated. The results showed that the anion exchange capacity decreased with an increase in the amount of MA, while alkaline treatment had no significant effect. Also, the cation exchange capacity increased with an increase in the amount of hydrophilic agent and reached a maximum point. The sorption equilibrium was achieved relatively fast within 40 mins, and the resin exhibited affinity towards lead (II), copper (II) and in particular uranium (VI). The adsorption of uranium was directly depended up on the pH value. Furthermore, the macroreticular chelating resin, containing amidoxime group had higher adsorption of uranium (VI) in comparison to other metal ions studied. Finally, the alkaline treatment enhanced the potential for much faster adsorption characteristics and the highly porous chelating resin provided a more favorable pore structure for the rapid rate of diffusion of metal ions.     

Geometrically nonlinear free vibration of shear deformable piezoelectric carbon nanotube/fiber/polymer multiscale laminated composite plates

The nonlinear free vibration of carbon nanotubes/fiber/polymer composite (CNTFPC) multi-scale plates with surface-bonded piezoelectric actuators is studied in this paper. The governing equations of the piezoelectric nanotubes/fiber/polymer multiscale laminated composite plates are derived based on first-order shear deformation plate theory (FSDT) and von Kármán geometrical nonlinearity. Halpin–Tsai equations and fiber micromechanics are used in hierarchy to predict the bulk material properties of the multiscale composite. The carbon nanotubes are assumed to be uniformly distributed and randomly oriented through the epoxy resin matrix. A perturbation scheme of multiple time scales is employed to determine the nonlinear vibration response and the nonlinear natural frequencies of the plates with immovable simply supported boundary conditions. The effects of the applied constant voltage, plate geometry, volume fraction of fibers and weight percentage of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) on the linear and nonlinear natural frequencies of the piezoelectric nanotubes/fiber/polymer multiscale composite plate are investigated through a detailed parametric study.     

Microwave-enhanced synthesis of aryl nitriles using dimeric orthopalladated complex of tribenzylamine and K4[Fe(CN)6]

The activity of palladacycle [Pd{C₆H₄(CH₂N(CH₂Ph)₂)} (μ-Br)]₂ complex was investigated in the synthesis of benzonitriles under both conventional and microwave irradiation conditions and their results were compared together. This complex is an efficient, stable, and non-sensitive to air and moisture catalyst for the cyanation reaction. The substituted benzonitriles were produced of various aryl halides in excellent yields and short reaction times using a catalytic amount of [Pd{C₆H₄(CH₂N(CH₂Ph)₂)} (μ-Br)]₂ complex and K₄[Fe(CN)₆] in DMF at 130 °C. In comparison to conventional heating conditions, the reactions under microwave irradiation gave higher yields in shorter reaction times.     

Collaboration of Ni,polyoxometalates and layered double hydroxides: synthesis,characterization, electrochemical and mechanism investigations as nano-catalyst in the Heck coupling reaction

Nickel (Ni) nanoparticles were immobilized on the surface of magnetic MgAl layered double hydroxide intercalated 10-molybdo-2-vanadophosphate (Fe–MgAl/Mo₁₀V₂–Ni) for the first time. The presence of Ni nanoparticles onthe high-surface area Fe–MgAl LDH structure in the presence of Mo₁₀V₂ makes this catalyst an ideal option in terms of efficiency and selectivity for Heck coupling reaction. Synergic effects of Mo₁₀V₂ and Ni were investigated by an electrochemical technique. Increasing of the ECSA of the catalyst compared to Fe–Mg–Al–Ni leads to enhancement of the catalytic activity and proves the synergic effect. A new catalytic mechanism was introduced for this kind of reaction. The resulting structure and its catalytic behavior were characterized by FT-IR, XRD, ICP-AES, TEM, SEM, EDX, EBSD, XPS, BET, VSM, CV, LSV and zeta potential analyses. More importantly, Fe–MgAl/Mo₁₀V₂–Ni can easily be separated from the reaction mixture using an external magnet and reused for at least four successive runs without any substantial reduction in its catalytic activity.     

Accelerated Heck reaction using ortho‐palladated complex in a nonaqueous ionic liquid with controlled microwave heating

The activity of {Pd[C₆H₂(CH₂CH₂NH₂)‐(OMe)₂,3,4] (µ‐Br)}₂ complex was investigated in the Heck–Mizoroki C C cross‐coupling reaction under conventional heating and microwave irradiation conditions in molten salt tetrabutylammonium bromide as the solvent and promoter at 130 °C. This complex in these conditions is an active and efficient catalyst for the Heck reaction of aryl iodides, bromides and even chlorides, and also arenesulfonyl chlorides. Copyright © 2011 John Wiley & Sons, Ltd.     

Spectral and molecular docking studies of nucleic acids/protein binding interactions of a novel organometallic palladium (II) complex containing bioactive PTA ligands: Its synthesis,anticancer effects and encapsulation in albumin nanoparticles

The organometallic palladium complex with nitrogen-containing heterocycles is a potent antitumor agent. Coordination of phosphorus ligands to organometallic complexes increases their hydrophilicity, promotes ligand−DNA interactions and damage level to cancer cells, and blocks division in target cells. In this study, a phosphaadamantane palladium complex ([Pd{(C,N)- (C₁₂H₈NH₂)} (PTA) Cl], PTA = 1,3,5-Triaza-7-phosphaadamantane) ( 2 ) was synthesized via the reaction of biologically active PTA with binuclear palladacycles [Pd₂{(C,N)-(C₁₂H₈NH₂)}₂(μ-Cl)₂] ( 1 ). In vitro studies of the complex with DNA (calf-thymus) explored by UV–Vis, emission titration, circular dichroism and helix melting methods showed that the complex interacts with DNA via an intercalative mechanism. Furthermore, competitive binding studies using warfarin, digoxin and ibuprofen site markers containing definite binding sites revealed the binding of the complex to site I on bovine serum albumin. The in vitro release mechanism of the palladium complex exhibited a biphasic pattern characterized by an initial burst release followed by a slower sustained release. Ultimately, in vitro evaluation of cytotoxicity and cell death showed that the complexes were able to decrease the viability of human cancer cell lines (MCF-7 and Jurkat) in a dose-dependent manner, but lower decreases were observed in the viability of normal fibroblast cells ASF-4 at the dosages evaluated. Finally, the order of in vitro anticancer activities was found to be consistent with the DNA-binding affinities.     

Synthesis and characterization of polyvinylpyrrolidone immobilized on magnetic nanoparticles modified by ionic liquid as a novel and recyclable catalyst for the three‐component synthesis of amidoalkyl naphthols

In this study, an efficient and green procedure is explained for the preparation of 1‐amidoalkyl‐2‐naphthols applying one‐pot condensation reaction of 2‐naphthol, amide and aromatic nanoparticles (Fe₃O₄@SiO₂@IL‐PVP) as a novel solid acid catalyst under solvent‐free conditions. The remarkable features of this method are short reaction time, high conversions, and high yield of product, easy workup procedures and solvent‐free conditions. The Fe₃O₄@SiO₂@IL‐PVP catalyst was characterized via Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction patterns (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and energy‐dispersive X‐ray spectroscopy (EDS). Also, nanocatalysts could be easily recovered by a simple magnet and reused for the next reactions without significant loss of its catalytic activity.     

(BeDABCO)2Pd2Cl6 as an efficient homogeneous catalyst for copper‐free Sonogashira cross‐coupling reaction

An efficient catalytic system using 1‐benzyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride and palladium chloride ((BeDABCO)₂Pd₂Cl₆) was developed for the Sonogashira reaction. In the presence of a catalytic amount of this efficient, stable homogeneous catalytic system that is non‐sensitive to air and moisture, various aryl halides were efficiently coupled with phenylacetylene in good yields in H₂O at 50°C under copper‐free conditions. Benzyl dabco as an efficient ligand and also a quaternary ammonium salt had an efficient stabilizing effect on the Pd(0) species. Copyright © 2014 John Wiley & Sons, Ltd.