Synthesis,characterization and cytotoxicity of new 2‐isonicotinoyl‐N‐phenylhydrazine‐1‐carbothioamide and its metal complexes

The reaction of the newly synthesized ligand, 2‐isonicotinoyl‐N‐phenylhydrazine‐1‐carbothioamide (H₃L), with acetate salt of Co (II), Cu (II),Ni (II) and Zn (II) led to isolation of four solid complexes. The ligand and complexes structure elucidation were based on elemental analyses, spectral analyses (IR, UV–Visible, ¹H and¹³C‐NMR, MS and ESR), TGA, molar conductivity and magnetic moments measurements. The results indicated that the ligand exists in the thioketo form, while on coordination to the metal ions; it behaves as mono‐negative bidentate chelate and exists in enol form. The optical band gap measurements of the ligand and its metal complexes are in the range 3.83–4.48 eV indicating their semi‐conducting character. The cytotoxicity examination of H₃L and its Zn (II) complex showed that the ligand have very strong cytotoxicity against both HCT‐116 and HEPG‐2 cell lines while, Zn (II) complex has moderate activity.     

Determination of primordial radionuclide concentrations in UAE groundwater using high-resolution gamma-ray spectrometry

Journal of Radioanalytical and Nuclear Chemistry - Groundwater is the most valuable resource in arid regions, such as UAE. Estimations of natural radionuclide concentrations are important to...     

Synthesis and Absorption Properties of Some 4-Thioaryl-1,8-naphthalimides and 4-Thioaryl-7H-benzimidazo-[2,1-a]-benz-[d,c]-isoquinolin-7-one Derivatives

A series of novel 4-thioaryl-1,8-naphthalimide derivatives were synthesized using 4-chloro-1,8-naphthalic anhydrid and arylthioles as starting materials. 4-thioaryl-1,8-naphthalic anhydride was treated with different primary amines and o-phenylene diamine or 1,2-diaminoethene to produce 4-thioaryl-1,8-naphthalimides and 4-thioaryl-7 H-benzimidazo-[2,1-a]-benz-[d,c]-isoquinolin-7-one derivatives, respectively. The UV/VIS absorption properties are discussed.     

A Simple and Highly Efficient One-Pot Procedure for the Synthesis of Amides via Beckmann Rearrangements Using 1-Tosylimidazole (TsIm)

A facile and highly efficient method for one-pot Beckmann rearrangement of ketoximes into N-substituted amides using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, ketoximes are refluxed with TsIm and Cs₂CO₃ in the presence of SiO₂ as a recyclable catalyst in DMF affording the corresponding amides in high yields. This methodology is highly efficient and regioselective for various structurally diverse ketoximes including symmetrical and unsymmetrical as well as cyclic oximes. The results of quantum mechanical studies used to rationalize the experimental outcomes are discussed.     

Spectral and Thermal Studies of Some New Metal Complexes Derived from N-[(Phenylamino)Thioxomethyl] Hydrazinocarbonyl Methyl Pyridinium Chloride (PTHMPC)

New metal complexes derived from the reaction of N-[(phenylamino)thioxomethyl] hydrazino carbonyl methyl pyridinium chloride (H₂L; PTHMPC) with some metal salts of the general formula MX₂ [(X = Cl^? and/or CH₃COO^?; M = Cd(II), UO₂(II), Mn(II) and Zr(IV)] were synthesized and characterized by elemental analyses, spectral analyses (IR, UV-vis., ¹H NMR), thermal analyses (TGA, DTG), and conductance and magnetic measurements. The results showed that the ligand exists in metal complexes either in the keto form or in the enol form. Moreover, the IR spectral data suggest that the acetate ion behaves in a monodentate manner. Semi-empirical calculations ZINDO/1, PM3, and AM1 have been used to study the molecular geometry and the harmonic vibrational spectra of the ligand and its metal complexes with the purpose of assisting the experimental assignment of the complexes. Generally, there is an agreement between the observed and the calculated spectra. Finally, the thermodynamic parameters (ΔE*, ΔH, ΔG, and ΔS) have been calculated from the data of thermal analyses (TGA and DTG).

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

The First Mitsunobu Protocol for Efficient Synthesis of α-Acyloxyphosphonates Using 4,4′-Azopyridine

Abstract

This is the first report on applying the Mitsunobu protocol for the synthesis of various α-acyloxyphosphonates using 4,4′-azopyridine and PPh₃ with diverse aromatic and aliphatic carboxylic acids. Under these conditions, diethyl azodicarboxylate (DEAD) as the traditional reagent for Mitsunobu reaction is not efficient. The insoluble pyridine hydrazine byproduct can be simply isolated and recycled to its azopyridine by an oxidation reaction and reused again.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Characterization data of compounds 3a–3z2 and NMR spectra.]

GRAPHICAL ABSTRACT      

Silicon-Containing Condensation Polymers Derived from Long-Chain Fatty Acids

Silicon-containing condensation polymers were prepared starting from difunctional silicon-containing carboxylic acids or diols derived from long-chain fatty acids. Polyesters were synthesized by reaction of diacids containing siloxane linkages with diols, and diols containing siloxane linkages with various diacids. 1,3-Bis (10-carboxydecyl)tetramethyldisiloxane was condensed with various diamines to yield polyamides. 1,3-Bis(11-hydroxyundecyl)tetramethyldisiloxane and 1,3-bis [9(10)-hydroxyoctadecyl]tetramethyldisiloxane were condensed with diisocyanates to yield polyurethanes. Polycarbonates were synthesized by reacting the diols containing siloxane linkages with ethyl chloroformate. Some polybenzimidazols were synthesized by heating the diesters of the silicon-containing carboxylic acids with 3,3′ -diaminobenzidine. Some of the polyurethanes and polybenzimidazoles were thermally stable up to 300°C as indicated by TGA.     

A computational investigation of the electronic properties of Octahedral Al n N n and Al n P n cages (n = 12, 16, 28, 36, and 48)

Density functionla theory (DFT) calculations are performed to characterize geometric and electronic features of the octahedral Al _n N _n and Al _n P _n cages (n = 12, 16, 28, 32, and 48). Toward this aim, ¹⁵N, ²⁷Al, and ³¹P chemical shielding (CS) tensors as well as natural charge analyses are calculated for the optimized structures. CS parameters detect three distinct electronic environments for atoms within the Al _n N _n and Al _n P _n cages. The chemical shifts of N2 sites belonging to a hexagon and surrounded by three hexagons and a square obtained are different from those of N3 sites belonging to a hexagon that is surrounded only by hexagons—due to different curvatures exerted at the sites with different local structures. In addition, there is an increasing tendency in the Δσ values of the three local structures, Δσ (N1) > Δσ (N2) > Δσ (N3), N1 sites belonging to four-membered rings. The chemical shieldings of those Al and P sites belonging to a hexagon that is surrounded only by hexagons in the cages (360.7–366.7 and 496.5–514.7 ppm) are close to those previously reported for AlP nanotubes. Three distinct electrostatic environments around the N, Al, and P nuclei are also confirmed by the calculated natural charges. It should be noted that the positively charged Al atoms on the cages turn out to be the available sites for adsorption of H2 molecules.     

Preconcentration and determination of methyl methacrylate by dispersive liquid–liquid microextraction

This article describes the preconcentration of methyl methacrylate in produced water by the dispersive liquid–liquid microextraction using extraction solvents lighter than water followed by gas chromatography. In the present experiments, 0.4 mL dispersive solvent (ethanol) containing 15.0 μL extraction solvent (toluene) was rapidly injected into the samples and followed by centrifuging and direct injection into the gas chromatograph equipped with flame ionization detector. The parameters affecting the extraction efficiency were evaluated and optimized including toluene (as extraction solvent), ethanol (as dispersive solvent), 15 μL and 0.4 mL (as the volume of extraction and dispersive solvents, respectively), pH 7, 20% ionic strength, and extraction's temperature and time of 20°C and 10 min, respectively. Under the optimum conditions, the figures of merits were determined to be LOD = 10 μg/L, dynamic range = 20–180 μg/L, RSD = 11% (n = 6). The maximum recovery under the optimized condition was determined to be 79.4%.     

In vitro surface biocompatibility of high-content silicon-substituted calcium phosphate ceramics

The present work investigates surface biocompatibility of silicon-substituted calcium phosphate ceramics. Different silicon-substituted calcium phosphate ceramic bodies were prepared from co-precipitated powders by sintering at 1300°C. The in vitro bioactivity of the ceramics was assessed in simulated body fluid (SBF) at 37°C for periods up to 4 weeks. The changes in the surface morphology and composition were determined by scanning electron microscopy (SEM) coupled with electron probe microanalysis and energy dispersive spectrometer (EDX). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to observe the change in ionic concentration of SBF after removal of the samples. The bioactivity of the ceramics increased with an increasing silicate ion substitution in a systematic way. The surface of ceramics with 2.23% silicon substitution was partially covered with apatite layer after one week, while ceramics with 8.1% silicon substitution were completely covered with apatite in the first week. The porous microstructure of high-concentration Si-substituted ceramics helps the dissolution of surface ions and the leaching process. This allows SBF to reach supersaturation in a short time and accelerate the deposition of apatite layer.