Voltammetric analysis of Cu (II), Cd (II) and Zn (II) complexes and their cyclic voltammetry with several cephalosporin antibiotics

Both osteryoung square wave voltammetry and cyclic voltammetry have been utilized to elucidate and confirm the possible complexation reaction that occur between the various cephalosporin antibiotics and either the toxic, non-essential metal ion, viz. Cd (II), or the essential but toxic (when their concentration exceeds certain level in serum) metal ions, viz. Cu (II) and Zn (II). Voltammetric measurements indicated the existence of 1:1 metal-to-ligand ratio (as in cephalexin and cephapirin complexes), 1:2 ratio (such as in cefamandole, cefuroxime and cefotaxime complexes) and 2:1 ratio in case of ceftazidime complexes. Adsorption behavior was evidenced for Cu (II)-cefuroxime or ceftazidime complexes as well as for those for Zn (II)-cephalexin or cephapirin. This phenomenon could be used for the determination of either the antibiotic or the metal ion using adsorptive stripping voltammetry. Detection limits down to 7x10(-10) M have been easily achieved.     

Thermodynamics of uranium extraction from nitric acid solution by TBP loaded on inert supporting material

Thermodynamic investigation of the extraction of both uranium(VI) and uranium(IV) from nitric acid solutions using tri-n-butyl phosphate (TBP) loaded on polyacrylic acid polymer (SM-7) as an inert supporting material has been done using batch technique. The effect of temperature on the equilibrium extraction values has been utilized to evaluate the change in standard thermodynamic quantities (viz. DH, DS, and DG). The Freundlich isotherm was successfully applied to the extraction data of both metal ions. The Dubinin-Radushkevich (D-R) isotherm was found to be valid only in case of U(IV) extraction. Based on the D-R expression, the maximum extraction capacity of loaded TBP and the mean free energy of U(IV) extraction have been determined.     

Fluorometric determination of some thioxanthene derivatives in dosage forms

A simple, highly sensitive method is presented for the determination of five pharmaceutically important thioxanthene derivatives, namely chlorprothixene, thiothixene, methixene hydrochloride, clopenthixol hydrochloride and flupentixol hydrochloride. The method involves the use of hexaamminecobalt(III) tricarbonatocobaltate(III) (HCTC) as an oxidant in aqueous sulphuric acid medium to induce fluorescence. The proposed method has been further applied to the determination of the five compounds in their dosage forms. The results compare favourably with those obtained by the official methods.     

Mesoporous cadmium sulfide nanoparticles derived from a new cadmium anthranilato complex: Characterization and induction of morphological abnormalities in pathogenic fungi

A cadmium complex of the general formula Cd(C₁₃H₉O₂NCl)₂(H₂O)₂ {C₁₃H₉O₂NCl = 2-(4-chlorophenylamino)benzoate} was synthesized and characterized regarding its CHN data, solution molar conductivity and spectroscopic (UV–Vis. and IR) properties. Cadmium sulfide nanoparticles (CdS NPs) were grown form the microcrystalline complex and thiourea via a hydrothermal route. The as-prepared NPs were assigned based on X-ray powder diffraction (PXRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and Brunauer – Emmett – Teller (BET) surface area measurements. The CdS absorption and emission spectra were also recorded that revealed an energy gap of 2.47 eV and large Stokes shift of 130 nm. For the as-prepared NPs, the measurements have also indicated a mesoporous structure and an average particle size of 20–28 nm associated with an average pore diameter of 11.21 nm. The as-synthesized CdS NPs acted as antifungal controlling agent against human and plant pathogenic fungi of serious environmental and health concerns. The NPs at concentration of 200 ppm inhibited several fungi with inhibition efficiency of 100% against Aspergillus ustus Au-28. The nanoparticles induced morphological abnormalities in fungal mycelia, conidia and vesicle. Additionally, they inhibited the conidia septum formation, accelerated the chlamydospores generation and enlarged the yeast cells.     

New Polymer Syntheses Part 60: A Facile Synthetic Route to Polyamides Based on Thieno[2,3-b]thiophene and Their Corrosion Inhibition Behavior

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer 1 a with different kinds of diacid chlorides(including oxalyl, adipoyl, sebacoyl, isophthaloyl,terephthaloyl, 4,4′-azodibenzoyl, 3,3′-azodibenzoyl, p-phenylene diacryloyl) in the presence of Li Cl and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy(including ~1H-NMR and ~(13)C-NMR) and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis(TGA), wide-angle X-ray diffraction analysis(WAXD) and scanning electron microscopy(SEM). Also, the corrosion inhibition behavior of selected examples of polyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol·L~(-1) HCl was studied using potentiodynamic polarization(PDP) and electrochemical impedance spectroscopy(EIS) methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency(P, %) was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer.The adsorption of these polymers was found to obey Langmuir adsorption isotherm.     

Enhancing the Photo and Biomedical Activity of ZnO by Incorporation with Zinc Silicate Nanocomposites

Highly active and non-toxic ZnO incorporated with zinc silicate (zinc silicate/ZnO) nanocomposites are synthesized via a simple and low-cost hydrothermal method followed by heat treatment. Different molar ratios from Si to Zn [1:20], [1:10], [1:8] and [1:6] are used to prepare different zinc silicate/ZnO nano composite materials which are assigned to ZS1, ZS2, ZS3 and ZS4 samples, respectively. The effect of calcination times and temperatures have been investigated on the crystallographic and morphological properties of the synthesized nano composite materials. The XRD analysis show that at very low molar ratios, zincite (ZnO) is the most predominant phase. However, at higher molar ratios, there are two phases coexist; hemimorphite (Zn₄Si₄O₇) and zincite. The TEM images show a uniform nanoplate-like shaped morphology from ZnO with well dispersed Zn₂SiO₄ nanoparticles. The S_BET is remarkably increased from 18.14 to 176.5 m².g⁻¹ by calcination up to 400 °C and then decreased to 72.2 m². g⁻¹ by further increasing in the calcinations temp up to 1,000 °C. The bio and photocatalytic activities of the composite nanomaterials have been investigated. Compared with the pure ZnO, the nano composites have been demonstrated as better photocatalysts for the degradation of Levafex golden yellow (LGY) dye as a model of organic dye pollutant under simulated sunlight irradiation. Moreover, the nano composites were evidenced to possess better and non-toxic antitumor activity towards hepatocellular carcinoma cell lines with (IC₅₀ = 11.2 μg.ml⁻¹ and LD₅₀ ˃ 50 mg. Kg⁻¹).     

Synthesis of Thiazolidine and Thiophene Derivatives for Evaluation as Anticancer Agents

The non-isolated adducts (3a,b) were used as key intermediates to synthesize some novel thiazolidine and thiophene derivatives. Compound (4) exhibited a remarkable antitumor activity against EAC cells compared with the Doxorubicin as a positive control.     

Flow-injection chemiluminometric determination of some thioxanthene derivatives in pharmaceutical formulations and biological fluids using the [Ru(dipy)3(2+)]-Ce(IV) system.

A flow-injection (FI) methodology using tris(2,2'-dipyridyl)ruthenium(II), [Ru(dipy)3(2+)], chemiluminescence (CL) was developed for the rapid and sensitive determination of three thioxanthene derivatives, namely zuclopenthixol hydrochloride, flupentixol hydrochloride and thiothixene. The method is based on the CL reaction of the studied thioxanthenes with [Ru(dipy)3(2+)] and Ce(IV) in a sulfuric acid medium. Under the optimum conditions, calibration graphs were obtained over the concentration ranges 0.002-6 migrograms/ml for zuclopenthixol hydrochloride, 0.5-15 micrograms/ml for flupentixol hydrochloride and 0.05-7.5 micrograms/ml for thiothixene. The limits of detection (s/n = 3) were 4.2 x 10(-9) mol/l zuclopenthixol hydrochloride, 2 x 10(-8) mol/l flupentixol hydrochloride and 4.5 x 10(-8) mol/l thiothixene. The method was successfully applied to the determination of these compounds in dosage forms and biological fluids.     

Optical band gap and refractive index dispersion parameters of As x Se70Te30−x (0≤x≤30 at.%) amorphous films

Amorphous As _x Se₇₀Te_30?x thin films with (0≤x≤30 at.%) were deposited onto glass substrates by using thermal evaporation method. The transmission spectra T(λ) of the films at normal incidence were measured in the wavelength range 400–2500 nm. A straightforward analysis proposed by Swanepoel based on the use of the maxima and minima of the interference fringes has been used to drive the film thickness, d, the complex index of refraction, n, and the extinction coefficient, k. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple and DiDomenico model (WDD). Increasing As content is found to affect the refractive index and the extinction coefficient of the As _x Se₇₀Te_30?x films. With increasing As content the optical band gap increases while the refractive index decreases. The optical absorption is due to allowed indirect transition. The chemical bond approach has been applied successfully to interpret the increase of the optical gap with increasing As content.