Bis‐aroylhydrazone based on 2,2′‐bis substituted diphenylamine for synthesis of new binuclear organotin (IV) complexes: Spectroscopic characterization,crystal structures,in vitro DNA‐binding,plasmid DNA cleavage,PCR and cytotoxicity against MCF7 cell line

New dinuclear organotin (IV) complexes, Me₄Sn₂L, Ph₄Sn₂L and Bu₄Sn₂L, have been synthesized from reaction of R₂SnCl₂ (R = Me, Ph and Bu) with a 2,2′‐bis‐substituted diphenylamine arοylidene hydrazone, H₄L. The synthesized compounds were investigated by elemental analysis and infrared, ¹H‐NMR and ¹¹⁹Sn‐NMR spectroscopy. The structures of H₄L, Me₄Sn₂L and Bu₄Sn₂L were also confirmed by X‐ray crystallography. H₄L molecules adopt (E)‐configuration and keto‐tautomeric form in the solid state. In all complexes, the bis‐hydrazone acts as a tetra‐anionic ligand with two contiguous ONO tridentate domains that coordinate the two R₂Sn moieties in the enolate form. The coordination environments of both tin centers are five‐coordinate. DNA‐binding studies were performed by UV–Vis spectroscopy, and the results indicate that the synthesized compounds significantly interact with calf thymus‐DNA in the intercalative mode. The results of polymerase chain reaction assay show that all the compounds affect on amplification of DNA, and complexes are more effective than ligands. The in vitro cytotoxicity against the human breast cancer line (MCF7) was determined using the MTT assay, and H₄L and the dibutytin complex showed higher activity.     

Type II c-Met inhibitors: molecular insight into crucial interactions for effective inhibition

The c-Met tyrosine kinase plays an important role in human cancers. Preclinical studies demonstrated that c-Met is over-expressed, mutated and amplified in a variety of human tumor types and design of more potent c-Met inhibitors is a priority. In this study, 14 molecular dynamics simulations of potent type II c-Met inhibitors were run to resolve the critical interactions responsible for high affinity of ligands towards c-Met considering the essential flexibility of protein–ligand interactions. Residues Phe1223 and Tyr1159, involved in pi-pi interactions were recognized as the most effective residues in the ligand binding in terms of binding free energies. Hydrogen bond interaction with Met1160 was also found necessary for effective type II ligand binding to c-Met.

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Polymeric ionic liquid material‐anchored Mn–porphyrin anion: Heterogeneous catalyst for aerobic oxidation of olefins

P(APTMACl)‐[Mn(TPPS)(OAc)] heterogeneous catalyst system comprised of anionic [Mn(tetrakis(4‐sulfonatophenyl)porphyrin)(OAc)] ([Mn(TPPS)(OAc)]) embedded within cationic cross‐linked polymeric ionic liquid (poly[(3‐acrylamidopropyl)trimethylammonium chloride], p(APTMACl)) hydrogel matrices was used for the selective aerobic oxidation of olefins. P(APTMACl)‐[Mn(TPPS)(OAc)] hydrogel was synthesized by radical polymerization in a solution of cationic APTMACl as an ionic liquid monomer, N,N′‐methylenebisacrylamide as cross‐linking agent, ammonium persulfate as initiator and N,N,N′,N′‐tetramethylmethylenediamine as accelerator in the presence of anionic [Mn(TPPS)(OAc)]. P(APTMACl)‐[Mn(TPPS)(OAc)] was characterized using Fourier transform infrared, diffuse reflectance UV–visible and atomic absorption spectroscopies and scanning electron microscopy. Differential scanning calorimetry was used for measuring the glass transition temperature. Catalytic activity of p(APTMACl)‐[Mn(TPPS)(OAc)] was investigated in the aerobic oxidation of olefins with emphasis on the effect of various parameters such as temperature, catalyst amount, substituent effect, etc. The catalyst was easily recovered from the reaction medium and could be re‐used for another seven runs without significant loss of activity.     

A new method for electrocatalytic oxidation of ascorbic acid at the Cu(II) zeolite-modified electrode

A new method is developed for the catalytic oxidation of ascorbic acid at graphite zeolite-modified electrode, doped with copper(II) (Cu²⁺A/ZCME). Copper(II) exchanged in zeolite type A acts as catalyst to oxidize ascorbic acid. The modified electrode lowered the overpotential of the reaction by ∼400 mV. First, the electrochemical behavior of copper(II), incorporated in the zeolite type A modified electrode, was studied. The results illustrate that diffusion can control the copper(II)/copper(0) redox process at the Cu²⁺A/ZCME. Then, the behavior of electrocatalytic oxidation reaction for ascorbic acid was researched. The electrode was employed to study electrocatalytic oxidation of ascorbic acid, using cyclic voltammetry and chronoamperometry as diagnostic techniques. The diffusion coefficient of ascorbic acid was equal to 1.028 × 10⁻⁵ cm² s⁻¹. A linear calibration graph was obtained over the ascorbic acid with a concentration range of 0.003-6.00 mmol L⁻¹. The detection limit (DL) of ascorbic acid was estimated as 2.76 × 10⁻⁷ mol L⁻¹. The relative standard deviations of 10 replicate measurements (performed on a single electrode at several ascorbic acid concentrations between 3.0 and 200 μmol L⁻¹) were measured between 1.0 and 2.4%.     

Phantom-Like Effects on Warped DGP Brane

We study phantom-like effect on the DGP brane embedded in a five-dimensional AdS bulk. We show that this effect can be realized without phantom matter on this warped DGP brahe. We investigate the role played by the bulk cosmological constant on the phantom-like effect on the brane and we show that it tends to reduce this effect. Also, warped compactification of the bulk manifold increases the values of the effective and total equation of state parameters of the model relative to the case with Minkowski bulk. We extend our study to the ease that induced curvature on the brahe is modified in the spirit of the f（R）-gravity.     

Secondary amines immobilized inside magnetic mesoporous materials as a recyclable basic and oxidative heterogeneous nanocatalyst for the synthesis of trisubstituted pyrimidine derivatives

Research on Chemical Intermediates - A novel magnetic MCM-41 nanocomposite-based catalyst is reported for the first time in the multicomponent synthesis of trisubstituted pyrimidines in which...     

Solvent Effects on Protonation Constants of Imatinib in Different Aqueous Solutions of Methanol at T = 298.15 K

Russian Journal of Physical Chemistry A - Imatinib (Gleevec) is a drug that is applied to treat cancer. It inhibits the Bcr-Abl tyrosine-kinase and therefore, it can slow growth or result in...     

Highly selective iodide membrane electrode based on a cerium salen.

A highly selective PVC membrane electrode based on a cerium-salen complex was prepared. The sensor displays an anti-Hofmeister selectivity sequence with a preference for iodide ion over many common organic and inorganic anions. The proposed electrode exhibits a near-Nernstian behavior over a wide concentration range (5.0 x 10(-2) - 8.0 x 10(-6) M) with a slope of 57.5 mV per decade, and a detection limit of 6.0 x 10(-6) M. The electrode has a very fast response time and can be used in the pH range of 3.0 - 1 1.0. It was applied, as an indicator electrode, in potentiometric titration of Ag+ ions.