A structural chemistry practitioner: a fox rather than a hedgehog. Reversibility of Friedel–Crafts acyl rearrangements

Structural Chemistry - A retrospective review of reversibility revealed in Friedel–Crafts acyl rearrangements of polycyclic aromatic ketones derived from the polycyclic aromatic hydrocarbons...     

Oxidation of bis(µ-halo)-bis[(diamine)copper(I)] complexes [LCuX]2; L = TMED, X = Cl, Br or I, L = TEED or TMPD, X = Cl, with the two electron organo oxidizing agent, tetrachloro-1,2-benzoquinone(TClBQ) in aprotic media: models for intermediates in catalytic catechol oxidase

Well structurally characterized bis(μ-halo)-bis[(diamine)copper(I)] complexes [LCuX]₂; L = TMED, tetramethylethylenediamine, X = Cl, Br or I and L = TEED, tetraethylethylenediamine, or TMPD, tetramethylpropane-diamine, X = Cl, react quantitatively with tetrachloro-1,2-benzoquinone (TClBQ) as two electron oxidizing agent in O₂-free CH₂Cl₂ or PhNO₂ to form a dimeric [LCuX]₂Cat (Cat = catechol) as indicated by cryoscopic measurements. Infrared spectra was in agreement with total reduction of TClBQ to the corresponding catechol. Electronic spectra indicated a dimeric distorted five coordinate Cu(II) and EPR spectra suggested a square pyramidal arrangement around the Cu(II) centers in [LCuX]₂Cat. The ligand field strength for diamine ligand was higher for the five member chelating ring (TMED) relative to the six membered one (TMPD). Electrochemical reduction of Cu centers in [LCuX]₂Cat were irreversible and occurred at a less negative potential when X = I.     

Synthesis of novel VO (II)‐thaizole complexes; spectral,conformational characterization,MOE‐docking and genotoxicity

New VO (II)‐thaizolyl hydrazine complexes were synthesized and characterized by analytical, spectral and theoretical techniques. Bi‐nuclear complexes were suggested for all synthesizes upon neutral poly‐dentate mode of bonding. UV–Vis and EPR spectra, proposed two structural geometries as, square‐planer and octahedral. TGA confirmed the contribution of solvent molecules through physical and/or coordinate‐bonding. XRD parameters calculated, displayed outstanding nanometer‐sizes for all nano‐crystalline compounds, which suffering slight imperfections. Also, SEM images showed, spherical‐shape that observed for most topographic particulates. Conformational study executed for all new synthesizes, demonstrated their optimized structural‐forms. Furthermore, important physical parameters were computed that predict essential characteristics as, biological efficiency. Predictable parameters as softness and electrophilicity, point to priority of VO (II)‐4d complex. Genotoxic study, was already examined, for all new synthesizes, against CT‐DNA and displayed complete deterioration for DNA, by influence of most tested compounds. Moreover, MOE‐docking technique, was executed against receptors of Y‐family DNA‐polymerase (4irk) and Key‐Enzyme Linking‐Metabolic Inflammation (4cyf). This docking study displayed the following ascending order; VO (II)‐4c,4irk ? VO (II)‐4d,4cyf ? VO (II)‐4c, 4cyf ? VO (II)‐4b, 4cyf, based on scoring‐energy values. This study concluded with promising prediction of these complexes in relation to DNA‐polymerase as well as inflammation enzyme that compared with known anti‐inflammatory drug (meloxicam).     

Equivalent dynamic thermoviscoelastic modeling of ionic polymers

Ionic polymers have attracted considerable attention due to their interesting sensing and actuating behavior which make them a proper choice for use in a wide range of applications including biomimetic robots and biomedical devices. The complicated electro‐chemo‐mechanical dynamics of ionic polymer actuators is a drawback for their applications in functional devices. Therefore, establishing a mathematical model which could effectively predict the actuators' dynamic behavior is of great interest. In this paper, a mathematical model, named equivalent dynamic thermoviscoelastic (EDT) model, based on thermal analogy and beam theory is proposed for dynamic analysis of bending‐type ionic polymer actuators. Then, the developed model is extended for analyzing the performance of the actuator in finite element software. The finite element analysis of the actuator enables consideration of material and geometric nonlinearities and facilitates modeling of functional devices based on the ionic polymer actuators. The proposed modeling approach is validated using experimental data. Copyright © 2015 John Wiley & Sons, Ltd.     

Copper–acetanilide complexes: synthesis,characterization, crystal structure,computational analysis and their application as heterogeneous catalysts for biodiesel synthesis from frying waste oils

Research on Chemical Intermediates - Novel copper complexes were prepared from acetanilide derivatives and deliberately characterized. The molar ratio obtained was 1:1 through neutral bi-dentate...     

Anti-arthritic activity of Tin oxide-Chitosan-Polyethylene glycol carvacrol nanoparticles against Freund’s adjuvant induced arthritic rat model via the inhibition of cyclooxygenase‑2 and prostaglandin E2

Rheumatoid arthritis (RA) results in increased rate of mortality in millions of people worldwide. Research utilizing Tin oxide – Chitosan- Polyethylene glycol Carvacrol (SCP-CAR) nanocomposites has gained increased attention because of its multipotent properties and application in diverse fields including medicinal preparations. The aim of the investigation was to synthesize and to examine the anti-arthritic ability of SCP-CAR nanocomposites against CFA -induced RA in rats. Arthritis induction was done by injecting 0.1 ml of Complete Freund’s adjuvant (CFA) intradermally. Body weight, weight of organs, hind paw volumes and arthritis score was assessed and the levels of inflammatory modulators such as IL-6, IL-1β, IL-10, TNF-α, PGE2 and COX-2 was examined using assay kits. Lipid peroxidation status, antioxidant enzyme activities and levels of liver function enzymes were evaluated using standard procedures. Histopathological changes observed in hind limb of experimental animals were viewed under microscope using H& E staining. The SCP-CAR nanocomposites treated arthritic animals showed increased bodyweight and reduced hind paw volume, organ weight and arthritis score together with elevated antioxidants status and depleted proinflammatory cytokines. Histopathological observation also showed reduction in bone destruction and penetration of inflammatory cells following treatment with SCP-CAR nanocomposites. Thus, together the findings depict the anti-arthritic and anti-inflammatory potential of SCP-CAR nanocomposites suggesting that it could be used as potent therapeutic agent to treat animals against arthritis induced by CFA.     

Quantification of Aluminum Gallium Arsenide (AlGaAs) Wafer Plasma Using Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS)

In this work, we report the results of the compositional analysis of an aluminum gallium arsenide (AlGaAs) sample using the calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique. The AlGaAs sample was doped with three various concentrations of gallium (Ga), arsenic (As), and aluminum (Al), as reported by the manufacturer, and the CF-LIBS technique was employed to identify the doping concentration. A pulsed Q-switched Nd: YAG laser capable of delivering 200 and 400 mJ energy at 532 and 1064 nm, respectively, was focused on the target sample for ablation, and the resulting emission spectra were captured using a LIBS 2000+ spectrometer covering the spectral range from 200 to 720 nm. The emission spectra of the AlGaAs sample yielded spectral lines of Ga, As, and Al. These lines were further used to calculate the plasma parameters, including electron temperature and electron number density. The Boltzmann plot method was used to calculate the electron temperature, and the average electron temperature was found to be 5744 ± 500 K. Furthermore, the electron number density was calculated from the Stark-broadened line profile method, and the average number density was calculated to be 6.5 × 10¹⁷ cm⁻³. It is further observed that the plasma parameters including electron temperature and electron number density have an increasing trend with laser irradiance and a decreasing trend along the plume length up to 2 mm. Finally, the elemental concentrations in terms of weight percentage using the CF-LIBS method were calculated to be Ga: 94%, Al: 4.77% and As: 1.23% for sample-1; Ga: 95.63%, Al: 1.15% and As: 3.22% for sample-2; and Ga: 97.32%, Al: 0.69% and As: 1.99% for sample-3. The certified concentrations were Ga: 95%, Al: 3% and As: 2% for sample-1; Ga: 96.05%, Al: 1% and As: 2.95% for sample-2; and Ga: 97.32%, Al: 0.69% and As: 1.99% for sample-3. The concentrations measured by CF-LIBS showed good agreement with the certified values reported by the manufacturer. These findings suggest that the CF-LIBS technique opens up an avenue for the industrial application of LIBS, where quantitative/qualitative analysis of the material is highly desirable.     

Visualisation of electrochemical processes at optically transparent carbon nanotube ultramicroelectrodes (OT-CNT-UMEs)

Optically transparent ultramicroelectrodes (OT-UMEs) comprising carbon nanotube (CNT) networks on quartz, are introduced and used to monitor quantitatively the interfacial concentration of tris(2,2'-bipyridine)ruthenium(II) during cyclic voltammetry. The OT-CNT-UMEs combine the attractive properties of small-scale electrodes, e.g., high diffusion rates and good signal-to-noise, with the ability to probe electrochemical processes optically, from the rear of the electrode. This enables optical measurements of the solution, close to the electrode surface, without significant interference from absorption or scattering processes.     

Investigation of Epithermal Molecular Formation and Hyperfine Interaction Effects on Kinetics of μCF

The role of epithermal effects in muon catalyzed fusion specially in the H/D/T mixture is investigated by Monte Carlo method. The results of the Monte Carlo simulation are used in the kinetics of CF in the steady-state condition. For this purpose we determine the values of thermalization rate (_th) and the probability of the dt molecular formation by epithermal t atoms during thermalization processes ( parameter). We have shown that including the epithermal effects in the kinetics of CF in different concentrations of hydrogen isotopes, increases the fusion yield per muon and it is not ignorable even in the D/T mixture. The reduction of the CF efficiency due to increasing the protium concentration is definitely confirmed here, even though the important effects such as the epithermal molecular formation, Ramsauer–Townsend effect and the hyperfine interactions are taken into account. We have shown that the epithermal effects disappear rapidly, whereas the unfavorable effects due to increasing protium, such as highly sticking probability in the pd and pt cycles, affect the fusion yield for a longer period of time. Recent experimental results at JINR in the H/D/T mixture are compatible with our conclusions.