Synthesis of poly (acrylamide-co-aconitic acid) adsorbents by gamma-irradiation,characterization, adsorption studies and application for cationic dyes removal

In this study, acrylamide (AAm)/aconitic acid (ACA) copolymers were prepared with two different mol% of aconitic acid 4%, 17% and were irradiated with gamma irradiation at different irradiation doses (4 - 25kGy). The percent yield was assigned by gravimetrical method. The effect of irradiation dose, pH and involved amounts of monomers (AAm/ACA) in hydrogels on swelling properties were investigated. The conversion of monomers to hydrogels was 100% at 25kGy. Poly(acrylamide-co-aconitic acid) P(AAm/ACA) hydrogels have been used for the adsorption of some aqueous solutions of dyes such as Methylene Blue (MB) and Safranine-O (S). The hydrogels were swollen in distilled water at pH 3, 5, 7, 8 and in aqueous solutions of dyes. The initial swelling rates of hydrogels are increased by increasing of pH. The effects of concentration of the aqueous solutions of dye and hydrogel composition on the adsorption were investigated. The adsorption is increased and changed depending on the structure of dye and composition of hydrogel.     

Relative pKa of some anilinium derivatives in methanol,acetonitrile, and tetrahydrofurane solvents

In this study, the relative pK_a values of nine anilinium derivatives in methanol (MeOH), acetonitrile (AN), and tetrahydrofurane (THF) solutions were successfully calculated with mean absolute deviations of 0.63, 0.68, and 0.75 pK_a units, respectively. To this aim, their gas‐phase basicities were computed using the CBS‐QB3 composite method. Also, conductor‐like polarizable continuum model (CPCM) with UAHF, UAKS and UA0 cavities and SM8 solvation models at HF/6‐31+G(d) level of theory were applied for the calculation of the solvation Gibbs free energies. The obtained results indicate that there is reliable correlation between the experimental and computed pK_a values in the studied solutions. Therefore, to extend the pK_a database for anilines, correlation equations were used to predict the pK_a values in the investigated solvents.     

Palladium supported on modified magnetic nanoparticles: a phosphine‐free and heterogeneous catalyst for Suzuki and Stille reactions

An efficient magnetic nanoparticle‐supported palladium (Fe₃O₄/SiO₂‐PAP‐Pd) catalyst is reported for the Suzuki cross‐coupling and Stille reactions. This method provides a novel and much improved modification of the Suzuki and Stille coupling reactions in terms of phosphine‐free catalyst, short reaction time, clean reaction and small quantity of catalyst. Another important feature of this method is that the catalyst can be easily recovered from the reaction mixture and reused with no loss of its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Syntheses,Characterization and X‐Ray Structures of the first Copper(I) and Silver(I) Complexes with ATT (ATT = 6‐Aza‐2‐thiothymine)

The reaction of copper(I) chloride with 6‐aza‐2‐thiothymine (ATT, 1 ) and triphenylphosphane in methanol/chloroform gives [(ATT)CuCl(PPh₃)] ( 2 ) as a neutral complex. [(ATT)Ag(NO₃)(PPh₃)₂]·MeOH ( 3 ) can be obtained by the reaction of 1 with silver(I) nitrate and triphenylphosphane in methanol/chloroform in excellent yields and the single crystals of 3 can be obtained from acetonitril solution. Both complexes were characterized by infrared spectroscopy, elemental analyses as well as by X‐ray diffraction studies. Crystal data for 2 at —80 °C: space group I2/a with a = 1859.3(1), b = 1143.2(1), c = 2208.2(1) pm, β = 104.84(1)°, Z = 8, R₁ = 0.0355 and for 3 at —80 °C: space group P2₁/c with a = 1344.1(1), b = 1553.6(1), c = 1977, 3(3) pm, β = 105.26(1)°, Z = 4, R₁ = 0.0436.     

Synthesis,characterization, cytotoxic activity and DNA-binding studies of cobalt (II) mixed-ligand complex containing pyridine-2,6-dicarboxylate ion and 2-aminopyrimidine

Treatment of pyridine-2,6-dicarboxylic acid and 2-aminopyrimidine with Co(NO₃)₂?6H₂O under hydrothermal conditions led to a new Co (II) complex [Co(amp)(pydc)(H₂O)₂]?H₂O (1), which was characterized by infrared spectroscopy, elemental analysis as well as X-ray diffraction studies. The DNA-binding behavior of the complex has been studied by UV–Vis absorption and fluorescence spectroscopic titration, viscosity measurements, thermal denaturation and circular dichroism (CD). The experimental results indicated that Co (II) complex was bound to DNA by an intercalative mode. The intrinsic binding constant of Co (II) complex with DNA was (3.80 ± 0.02) × 10⁴ M^?1. The biological effects of the Co (II) complex were also studied by MTT assay in MCF-7 and HT-29 cancer cell lines. Treatment of MCF-7 and HT-29 cells with Co (II) complex resulted in a concentration-dependent cell growth inhibition.     

Synthesis of new di‐ and tetraazadibenzosulfoxide macrocycolic compounds

Novel macrocyclic di and tetraamide compounds have been synthesized by the reaction of 2‐2′‐sulfoxide‐bis‐(4‐methyl phenoxy) aceticester or aceticacid chloride) (obtained from corresponding bisphenol) with appropriate diamines. Also the results of the presence of base as template are discussed and compared.     

A Facile Synthesis of New Pyrazolo[3,4‐d]pyrimidine Derivatives via a One‐Pot Four‐Component Reaction with Sodium Acetate Supported on Basic Alumina as Promoter

An efficient one‐pot procedure for the synthesis of 3‐amino‐6‐aryl‐2‐phenylpyrazolo[3,4‐d]pyrimidine derivatives, through the reaction of aldehydes, malononitrile, benzamidine hydrochloride, and hydrazine hydrate in the presence of basic alumina‐supported sodium acetate (AcONa/Al₂O₃) under reflux conditions, is reported. This protocol has some advantages, including the use of a simple and one‐pot synthetic approach to attain pyrazolo[3,4‐d]pyrimidine directly from four readily available starting materials, simple workup, high overall yields of the products, and the simultaneous conversion of a NO₂ to an amino group, offering an opportunity to synthesize more complex structures.     

Simultaneous trace-levels determination of Hg(II) and Pb(II) ions in various samples using a modified carbon paste electrode based on multi-walled carbon nanotubes and a new synthesized Schiff base

A modified carbon paste electrode based on multi-walled carbon nanotubes (MWCNTs) and 3-(4-methoxybenzylideneamino)-2-thioxothiazolodin-4-one as a new synthesized Schiff base was constructed for the simultaneous determination of trace amounts of Hg(II) and Pb(II) by square wave anodic stripping voltammetry. The modified electrode showed an excellent selectivity and stability for Hg(II) and Pb(II) determinations and for accelerated electron transfer between the electrode and the analytes. The electrochemical properties and applications of the modified electrode were studied. Operational parameters such as pH, deposition potential and deposition time were optimized for the purpose of determination of traces of metal ions at pH 3.0. Under optimal conditions the limits of detection, based on three times the background noise, were 9.0 × 10⁻⁴ and 6.0 × 10⁻⁴ μmol L⁻¹ for Hg(II) and Pb(II) with a 90 s preconcentration, respectively. In addition, the modified electrode displayed a good reproducibility and selectivity, making it suitable for the simultaneous determination of Hg(II) and Pb(II) in real samples such as sea water, waste water, tobacco, marine and human teeth samples.