Chemical Review and Letters

Abstract

Abstract The corrosion inhibition efficiency of (3-(4-chlorophenyl isoxazole-5-yl) methanol (CPIM) and (3-(2,4 dichlorophenolisoxazole-5-yl) methanol (DCPIM) for mild steel in 1 M HCl has been studied using electrochemical methods at 40 and 50 °C. Polarization studies showed that the inhibitors are efficient mixed-type corrosion inhibitors, and their inhibition performance increased with the rise of inhibitor concentration and decrease of temperature. The result of EIS measurements was analyzed through an appropriate equivalent circuit model to model the corrosion inhibition.

Abstract < p>Cultivated fishes are major protein and microelement sources for all sorts of people in Bangladesh due to its availability and affordability. Since heavy metals are persistent in the aquatic environment, these metals can accumulate in the food chain. Cultivated fishes containing heavy metals can cause a carcinogenic and non-carcinogenic risk to human as it biologically accumulates heavy metals from commercial feeds. This study was designed to access the content of heavy metals in the flesh of some cultivated fish species through consuming commercial fish feeds available in Bangladesh and potential health risk calculation for consumers due to intake daily. The concentration (mg/kg, dry weight) range of heavy metals like; Pb (4.56- 7.08), Cd (0.23- 1.28), Cr (4.00-7.08), Cu (11.23- 20.62), As (0.08- 0.34), Hg (0.05- 0.34) in selected commercial fish feeds and Pb (4.35-8.03), Cd (0.87- 1.35), Cr (4.71-8.98), Cu (14.00- 31.80), As (0.17- 0.28), Hg (0.08- 0.41) in fishes were accessed by inductive coupled plasma optical emission spectroscopy (ICP-OES). The recorded concentration value for selected metals in fish tissues and feeds were also compared with the safe limit proposed by World health organization (WHO, 1995), Food and Agricultural Organization (FAO, 1983), European Union (EU, 2001). This study also estimated the carcinogenic and non- carcinogenic risk due to daily consumption of these cultivated fishes for a certain age.

Abstract The new derivatives of S-aryl (trichloroacetyl) carbamothioate were prepared from a two-component reaction of 2-naphthalenethiol or thiophenol derivatives and trichloroacetyl isocyanate in CH2Cl2 at room temperature at high yields. The reaction was a simple and efficient procedure with high yield and available stating materials in a short time for the synthesis of these compounds that no side reactions were observed. The structures of the products were confirmed by IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis. Quantum theoretical calculations for the three structures of compounds (3a, 3b and 3c) were performed using the G3MP2, LC-ωPBE, MP2, and B3LYP methods with the 6-311+G(d,p) basis set. Geometric parameters of optimized the structures were compared with the experimental measurements. The structures of the products were confirmed by IR, 1H NMR, 13C NMR, and elemental analysis. IR spectra data and 1H NMR and 13C NMR chemical shifts computations of the compounds were calculated. Frontier molecular orbitals (FMOs), total density of states (DOS), thermodynamic parameters and molecular electrostatic potentials (MEP) of the title compounds were investigated by theoretical calculations. Molecular properties such as the ionization potential (I), electron affinity (A), chemical hardness (η), electronic chemical potential (μ) and electrophilicity (ω) were investigated for the structures. Consequently, there was an excellent agreement between experimental and theoretical results.

Abstract An efficient and environment friendly valuable synthon of 1, 5 benzodiazepine derivatives were synthesized having unique physical and medicinal properties. This reaction is performed by mesoporous binary mixed metal oxide SiO2-Al2O3 which is synthesized by hydrothermal method at high temperature. This mesoporous material is investigated by XRD, SEM, EDS, TEM, TPD and BET surface area. Present method offers several remarkable advantages such as non-toxic, noncorrosive and easy work-up procedure for the purification of product with non-chromatographic method, ecofriendly reaction condition.

Abstract 1, 4-Diazabicyclo[2.2.2]octanium diacetate supplies an environmentally friendly procedure for the synthesis of 2,4,5-trisubstituted imidazoles through one-pot multicomponent condensation of benzyl or benzoin and ammonium acetate with various aldehydes. These compounds were obtained in high yields and short reaction times. The catalyst could be easily recovered and reused for five cycles with almost consistent activity. All of synthesized compounds were characterized by their physical constant, comparison with authentic samples, IR, 1H NMR, 13C NMR spectroscopy and elemental analysis.

Abstract The present study aims to assess the potentials of immobilized bacteria in the remediation of anions within the effluents by determining the levels of the anions before and after the remediation. Industrial Effluents Samples from Gashash Tanneries (TAN1), Larabee Tannery Industry (TAN2) and Z Tannery Industries (TAN3) in Kano State, Nigeria were collected monthly for six months (August 2017 to January 2018). Bacteria were isolated from the effluents and immobilized on agar-agar. The effluent samples were analyzed for the anions before and after the treatment using DR/2010 HACH portable data logging spectrophotometer. Different masses (5 g, 10 g, 15 g, 20 g, and 25 g) of the bacteria were used in the treatment of 250 ml of the effluents for ten days in a shaker incubator (Gallenkamp-OC-4364-L) at the temperature 30 °C and speed of 60 rpm. Pre-treatment analysis of the effluents for nitrate (NO-3), Sulphate (SO2-4), Phosphate (PO3-4) and Chloride (Cl-) give the following results; NO-3 ranged (25.35±17.16-28.12±10.72 mg/l); SO2-4 (67.00±5.93-114.83±53.20 mg/l); PO3-4 (26.16±22.93-34.17±16.73 mg/l) and Cl- (22.57±9.64-26.00a±4.86 mg/l). No statistical difference (p ≤ 0.05) was observed for all the anions among the different industries. The bacterial isolates were identified as Neisseria spp, Bacillus cereus, and Staphylococcus aureus, in TAN1, TAN2, and TAN3, respectively. After treatment of the effluents with the different masses of the isolated bacteria, the mean level of NO-3 were found to range as (6.17±6.67-20.78±7.76); SO2-4 (25.73±17.84-46.00±46.81); PO3-4 (11.45±12.02-28.19±9.09) and Cl-(0.38±1.83-15.36±13.58). The results of Post-treatment analysis showed that there is an overall decrease in the levels of the anions determined when compared with that of the pre-treatment. The overall percentage reduction of the immobilized bacteria in the treatment of the respective effluents was in the order TAN3 (57%)>TAN1 (49%)>TAN2 (47%). Therefore, the immobilized bacteria are having higher potentials for the treatment of the anions in the effluents.

Abstract < p>In this work, the interaction between Flutamide (FLU) anticancer drug with nucleobases such as cytosine, thymine, uracil, and adenine was studied by density functional theory (DFT) methods from a thermodynamic point of view. The Gibbs free energy (ΔG) and enthalpy (ΔH) of C-FLU, T-FLU, U-FLU and A-FLU complexes were computed and demonstrate that the stronger interaction between cytosine and FLU and the adsorption of the drug on the bases proceeds spontaneously. The negative value of ΔH indicates that the adsorption of FLU drug on the cytosine, thymine and uracil bases are exothermic, these results confirmed ΔE results. During the interaction of Flutamide drug with nucleobases, the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were significantly changed. The values of the energy gap (Eg) reduced during the adsorption of the FLU drug onto bases which confirmed that the reactivity of the resulted complex increase upon adsorption. On the other hand, as a result of theoretical calculations, the values of the Eg for the Base-FLU structures in water solution are decreased in comparison to the corresponding values in the gas phase, indicating more the reactivity of the studied complexes in the aqueous medium.