Dichloro-bis-(pyridine-2-yl-undecyl-amine)zinc(II), [ZnCl2(C16N2H26)2]: Synthesis,characterization and antimalarial activity

A nitrogen-based ligand (pyridine-2-yl-undecyl-amine) (1) was synthesized and used for the synthesis of a Zn(II) compound (dichloro-bis(pyridine-2-yl-undecyl-amine)zinc(II)) (2). Compound 2 was synthesized and characterized using IR, ¹H NMR, and ¹³C{¹H} NMR spectroscopy. The crystal structure of 2 was determined using single-crystal X-ray crystallography. The compound was tested for its anti-malarial activity using two methods, a semi-quantitative micro-assay and a previously self-developed quantitative in vitro method. Both methods were used to study the efficiency of 2 to inhibit the formation of the malaria pigment considered an important target of many anti-malarial drugs such as chloroquine and amodaquine. The efficiency of 2 to prevent the formation of β-hematin was 71.4%. The efficiency of amodiaquine as a standard drug was reported at 93.8%.     

Purification and identification of corn peptides that facilitate alcohol metabolism by semi‐preparative high‐performance liquid chromatography and nano liquid chromatography with electrospray ionization tandem mass spectrometry

In this study, peptides that facilitate alcohol metabolism were purified and identified from corn protein hydrolysates. The ultra‐filtered fraction with a molecular weight < 3 kDa (F3) potential activity was separated into six fractions (F3‐H1–F3‐H6) by semi‐preparative high‐performance liquid chromatography. Among the resultant six fractions, F3‐H4 and F3‐H5 exhibited the highest ability to eliminate alcohol in vivo. A total of 16 peptides with strong signal values were identified from F3‐H4 and F3‐H5 fractions by nano liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Several identified peptides were then selected and synthesized to determine their potential to facilitate alcohol metabolism. We found that Leu‐Leu and Pro‐Phe were the key structure units in Gln‐Leu‐Leu‐Pro‐Phe responsible for this peptide's ability to facilitate alcohol metabolism. However, the role of Leu‐Leu and Pro‐Phe may be affected by peptide chain length and hydrophobic properties. Our results have thus provided some insight into the study of the structure–activity relationships of corn peptides.     

The use of chloranil for spectrophotometric determination of some tranquillizers and antidepressants

Chlorpromazine hydrochloride, promethazine hydrochloride, promazine hydrochloride, perphenazine, thioridazine hydrochloride, chlorprothexine, opipramol hydrochloride, amitriptyline hydrochloride, imipramine hydrochloride and hydroxyzine hydrochloride are estimated in their pure state and in pharmaceutical formulations by means of the reaction of the free bases with chloranil in dioxan-ethanol medium to give a coloured product with maximal absorbance at 550 nm. The method is precise, accurate and specific and recommended for routine analysis for the drugs mentioned.     

Synthesis and Characterization of Heteropolynuclear Redox Active Materials[FerCuCl]4YY′; Y?=?Y′?=?O, Y?=?Y′?=?Cat and Y?=?O, Y′?=?Cat, Fer?=?N,N-dimethylaminomethylferrocene and Cat?=?3,4,5,6-tetrachlorocatecholato Ligand

This paper describes the synthesis and characterization of heteropolynuclear redox active materials [FerCuCl]₄YY′, Y = Y′ = O, Y = Y′ = Cat and Y = O, Y′ = Cat, Fer = N,N-dimethylaminomethylferrocene and Cat = 3,4, 5,6-tetrachlorocatecholato ligand. Manometric O₂ uptake measurements in PhNO₂ show that tetranuclear [FerCuCl]₄ and [FerCuCl]₄Cat give the tetranuclear oxocopper(II) products [FerCuCl]₄O₂ and [FerCuCl]₄CatO, respectively. The absence of carbonyl stretching vibrational bands in [FerCuCl]₄Cat₂ and [FerCuCl]₄CatO suggest that tetrachloro-1,2-benzoquinone (TClBQ) is reduced to the corresponding catecholete during the oxidation of copper(I) centers in [FerCuCl]₄. The near i.r. electronic spectra for [FerCuCl]₄O₂, [FerCuCl]₄CatO and [FerCuCl]₄Cat₂ exhibit broad intense split maxima in the 750–875 nm range, attributed to a minimum of three halide ligands per Cu. Room temperature solid state e.p.r. spectra for [FerCuCl]₄CatO and [FerCuCl]₄Cat₂ are of the axial type, suggesting a square pyramidal geometry around Cu^II.     

Resonant transfer of excitation between two molecules using Maxwell fields

The matrix element for the resonant transfer of excitation between two molecules possessing electric and magnetic multipole moments of arbitrary order is calculated using quantum electrodynamical response theory. A prerequisite of the method is the functional form for the lth order linear electric and magnetic multipole dependent electric displacement and magnetic field operators in the neighborhood of a molecule, whose derivation is also given. The initially unexcited species is viewed as a test body accepting energy resonantly via coupling to the Maxwell fields of the excited multipole source molecule. The generalized electric-electric multipole contribution to the matrix element is shown to agree with an earlier calculation using time-dependent perturbation theory. As an application involving both electric and magnetic terms, the rate of excitation transfer between two chiral molecules is computed and found to depend on the handedness of each species.     

Novel application of modified multiwalled carbon nanotubes as a solid phase extraction adsorbent for the determination of polyhalogenated organic pollutants in aqueous solution

This paper describes a novel application of pristine and chemically modified multiwalled carbon nanotubes (MWCNTs) as the packing materials for the determination of different polyhalogenated organic pollutants, pentachlorophenol, 2,4,5-trichlorophenol, 3,3′,4,4′-tetrachlorobiphenyl and 2,2′,5,5′-tetrabromobiphenyl, from aqueous solution based on solid phase extraction. The modified MWCNTs were characterized using different techniques and the results revealed the successful modification of the MWCNTs with octadecyl amine and poly(ethylene glycol), separately. Factors that maybe influence the preconcentration efficiency, such as sample flow rate, adsorbent mass, sample pH and sample volume, were studied. Desorption of the target analytes was studied using different solvents and the results showed that acetone was the best solvent for all the analytes compared with methanol and hexane. All the results indicated that the proposed method could be used for the simultaneous determination of different pollutants in environmental water samples at trace levels.     

Construction of traveling wave solutions of the (2 + 1)-dimensional modified KdV-KP equation

Traveling wave solutions have played a vital role in demonstrating the wave character of nonlinear problems emerging in the field of mathematical sciences and engineering. To depict the nature of propagation of the nonlinear waves in nature, a range of nonlinear evolution equations has been proposed and investigated in the existing literature. In this article, solitary and traveling periodic wave solutions for the (2 + 1)-dimensional modified KdV-KP equation are derived by employing an ansatz method, named the enhanced (G′/G)-expansion method. For this continued equation, abundant solitary wave solutions and nonlinear periodic wave solutions, along with some free parameters, are obtained. We have derived the exact expressions for the solitary waves that arise in the continuum-modified KdV-KP model. We study the significance of parameters numerically that arise in the obtained solutions. These parameters play an important role in the physical structure and propagation directions of the wave that characterizes the wave pattern. We discuss the relation between velocity and parameters and illustrate them graphically. Our numerical analysis suggests that the taller solitons are narrower than shorter waves and can travel faster. In addition, graphical representations of some obtained solutions along with their contour plot and wave train profiles are presented. The speed, as well as the profile of these solitary waves, is highly sensitive to the free parameters. Our results establish that the continuum-modified KdV-KP system supports solitary waves having different shapes and speeds for different values of the parameters.     

Transport properties of alternative fuel microemulsions based on sugar surfactant

Electrical conductivity of fuel microemulsion composed of diesel, pentanol, water, and sucrose laurate as surfactant was investigated over a wide range of water contents varying from 0 to 90?wt% and temperature varying from 10°C to 50°C. Conductivity measurements were performed on samples, the composition of which lie along the one-phase channel using a conductivity meter. Activation energy of conduction flow was evaluated. The hydrodynamic radius as a function of temperature in the aqueous phase-rich region (90?wt%) was measured using the dynamic light scattering (DLS) method. The microstructure of the microemulsion was further investigated by NMR diffusometry by which the self-diffusion coefficients for water were determined at 25°C. Electrical conductivity increases with water content up to 40?wt% and the percolation threshold was observed, and then stabilizes between 40 and 80?wt% then decreases. Percolation threshold temperature at constant composition was monitored as 36°C for water contents below 80?wt% and as 34°C for water contents above that. As predicted by the conductivity measurements, the determined self-diffusion coefficients of water confirmed the structural transition from discrete W/O droplets to bi-continuous phase and finally to O/W droplet microemulsion.     

An Overview of Recent Advances in the Synthesis of Organic Unsymmetrical Disulfides

Organic unsymmetrical disulfides have been extensively applied in various academic and industrial fields including intermediates in organic synthesis, agriculture, and food science, natural materials, biochemistry, pharmaceutical and medicine chemistry, polymers, material engineering, etc. They play a crucial role in the fabrication of various biological active sulfur heterocycles. Due to broad and extensive applications, many methods have been developed for the synthesis of unsymmetrical S−S and efforts have been made to improve some issues such as cost, energy efficiency, green chemistry, avoid or minimizing waste generation. Several outstanding review articles have been previously published highlighting the advances of S−S bond formation, in general, using various reagents under different conditions in the absence or presence of oxidants/catalysts. In 2020, a review paper was published by our group focusing on recent developments since 2014 in the synthesis of organic symmetrical disulfides. However, investigations on new catalytic methods are being regularly reported and new types of unsymmetrical disulfides are synthesized. The present overview has attempted to systematically summarize recent advances in the process of unsymmetrical S−S bond formation with a major focus since 2010, highlighting mechanistic considerations, substrate scope, advantages, and limitations. The patents are not studied in this overview.