Classical chemical sciences
The title compound is formed by the air oxidation of 2-aminomethylpyridine in 95% ethanol in the presence of copper(II) nitrate with condensation of the resulting picolinamide molecules in situ to form the imide moiety. The compound crystallizes as a dihydrate (one water position is only 75% occupied) and the Cu(II) ion is 5-coordinate square-pyramidal, the basal plane being occupied by four nitrogen atoms (three from pyridine rings and the fourth being the imide N-atom) in a nearly planar array [mean deviation = 0.28(3) Å) with the Cu(II) ion slightly above the plane [0.128(9) Å]. The axial position is occupied by the carbonyl oxygen atom of a coordinated picolinamide [Cu-O = 2.273(10) Å]. The crystal is stabilized by multiple hydrogen bonding interactions with both water molecules and the amide NH2 serving as donors and the nitrate ion, imide oxygen atoms and water molecules serving as acceptors.
Keywords: Cu(II)-catalyzed autoxidation, 2-aminomethylpyridine; coordinated picolinamide; N,N-bis(picolinyl)imidate ligand
Properties, or descriptors, of artemisinin and some of its derivatives have been obtained from known solubilities and water-octanol partition coefficients. These descriptors can then be combined with already known equations to yield water-solvent partition coefficients and solubilities in a very large number of solvents, so that it is now possible to select suitable solvents for purification, etc. Combination of the descriptors with known equations for blood-tissue partitions enables partition coefficients to be estimated for partitions from blood to brain, muscle, liver, lung, kidney, heart, skin and fat. Where data on blood-tissue partitions exist, there is agreement with experiment.
Keywords: Artemisinin, linear free energy relationship, solubility, partition coefficients, blood-tissue partitions
Reactions of substituted alcohols (R-OH, where R = CH3, (CH3)2CH, SiH3CH2, NH2CH2, or FCH2) and isocyanates (X-NCO where X = CH3, CH2F, C6H5, SiH3 or SiH3CH2) were studied using B3LYP/6-31G* calculations. Activation energies of the four-membered cyclic transition complexes (TS) were calculated. In case of substituted methanols and methyl isocyanate the activation energy and Gibbs free energy was found to increase in the following order: CH3 < (CH3)2CH < SiH3CH2 < NH2CH2 < FCH2. Substituting the isocyanates changed the order with respect to the activation energy and Gibbs free energy: FCH2 < SiH3CH2 < C6H5 < CH3 < SiH3. Solvent effect was also studied for the reaction of CH3NCO with CH3OH as an example using the SCRF (CPCM) method and chlorobenzene as solvent. The activation energy was found to be very similar in an environment of a low permittivity solvent (G(sol)=38.00 kcal/mol) and in the gas phase (G(g)=37.77 kcal/mol). Vibrational frequencies and forces in transition state were calculated. Enthalpies (H) and Gibbs-free energies (G) were determined at 298.16 K and 1 atm.
Keywords: ab initio calculation, urethane bond formation, addition reaction mechanism
Chromatographic retention factor data were measured for a chemically diverse set of thirty-seven organic solutes on a 1-(2-hydroxyethyl)-3- methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([EtOHMIm]+[FAP]–) ionic liquid stationary phase at both 323 K and 353 K. The measured retention factors were combined with published gas-to-liquid partition coefficient data for solutes dissolved in ([EtOHMIm]+[FAP]–) and with published gas-to-water partition coefficient data to yield gas-to-anhydrous ionic liquid and water-toanhydrous ionic liquid partition coefficients. The three sets of partition coefficients were correlated with the Abraham solvation parameter model. The derived Abraham model correlations describe the experimental gas-to-ionic liquid and water-to-ionic liquid partition coefficient data to within an average standard deviation of 0.12 log units.
Keywords: Chromatographic retention factors, partition coefficients, ionic liquids, solvation parameter model
Fullerene C60 and C70 were discovered in 2010 by means of infrared spectroscopy in a series of astrophysical objects like for example planetary and protoplanetary nebulae and reflection nebulae. These discoveries suggest that C60 and C70 must be widespread in the interstellar medium and may contribute as neutral species or as radical cation (C60+• and C70 +•) to the DIBs, the Diffuse Interstellar Bands which are attributed to the electronic transitions of molecules and radicals. In this paper are reported the electronic absorption spectra of both C60 and C70 and of their radical cations C60+• and C70+• together with the molar extinction coefficients of all the main absorption bands. All these experimental data are key tools for the qualitative and quantitative search and recognition of these molecules and radicals in space using electronic transitions rather than infrared transition. Furthermore, the electronic absorption bands and molar extinction coefficients of hydrogenated and perdeuterated fullerenes (known as fulleranes) and higher fullerenes are reported.
Keywords: electronic absorption spectra; radical cation; fullerene C60; fullerene C70; molar extinction coefficient
The nucleophilic introduction of ethoxycarbonylmethylthio, 1,2,4-triazolo and azido- groups into 5-chloro-3-methyl-4-nitro-1- phenylpyrazole 1 is described. 5-Azidopyrazole 5 reacts at ambient temperature with phosphines or phosphites 6a-c to yield phosphazenes 7a-c. The use of phosphites leads to "Michaelis-Arbuzov type" rearrangement; thus 5 reacts in boiling 6c and heating of the trimethoxyphosphazene 7c in refluxing chlorobenzene gave 9. Compounds 5, 7a,b and 9 can be converted to the corresponding aminopyrazoles. The cyclization of 5 by heating with methanesulfonic acid affords 4H-pyrazolo[5,1-b]benzimidazole derivative.
Keywords: 5-chloro-3-methyl-4-nitro-1-phenylpyrazole; Michaelis-Arbuzov type rearrangement
Keywords:
The oxidation of some organic sulfides by benzyltriethylammonium chlorochromate (BTEACC) resulted in the formation of the corresponding sulfoxides. The reaction is first order with respect to both BTEACC and the sulfide. The reaction is catalysed by toluene-psulfonic acid (TsOH). The oxidation was studied in nineteen different organic solvents. An analysis of the solvent effect by Swain's equation showed that the both cation- and anion-solvating powers of the solvents play important roles. The correlation analyses of the rate of oxidation of thirty four sulfides were performed in terms of various single and multiparametric equations. For the aryl methyl sulfides, the best correlation is obtained with Charton's LDR and LDRS equations. The oxidation of alkyl phenyl sulfides exhibited a very good correlation in terms of Pavelich-Taft equation. The polar reaction constants are negative indicating an electron-deficient sulfur centre in the rate-determining step. A mechanism involving formation of a sulphenium cation intermediate in the slow step has been proposed.
Keywords: Correlation analysis, halochromate, kinetics, mechanism, oxidation, benzyltriethylammonium chlorochromate
A series of spiro[acenaphthylene-1,2′-pyrrolidine] derivatives (4a-j) were synthesized by highly efficient one-pot three-component reaction of acenaphthenequinone, sarcosine and Knoevenagel adduct in 2,2,2-trifluoroethanol as a reusable green solvent. All the synthesized compounds were screened for their ‘in vitro’ antimalarial activity against the growth of Plasmodium falciparum, the malaria causing parasite. Some of them showed antimalarial activity with IC50 values as low as 0.003 and 0.005 mg mL-1. The compounds were evaluated for their antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes and for antifungal activity against Candida albicans, Aspergillus niger, and Aspergillus clavatus. Some of the compounds exhibited excellent antibacterial activity and compounds 4c and 4e demonstrated significant antifungal activities than the standard drugs.
Keywords: Spiro[acenaphthylene-1,2’-pyrrolidines], Knoevenagel adduct, trifluoroethanol, antimalarial and antimicrobial activities
Simple, precise and accurate visible spectrophotometric procedure was developed for the quantitative determination of two antibacterials, ampicillin and cloxacillin in a fixed dose combination. The method exploits the formation of charge transfer complexes between the antibacterials and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to determine the components of the drugs in a dosage form. The effect of different variables on the development and stability of the complexes were studied and optimized. Beer’s law was obeyed. The method was successfully applied to the determination of the target analytes in different brands of the fixed dose combination.
Keywords: ampicillin, cloxacillin, charge transfer, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)
Materials and environmental chemistry
The Fe3+-doped TiO2 nanoparticles were synthesized by sol-gel method in an aqueous solution at a temperature of 160 °C. The effect of particle size, Fe3+-doping and dosage on the photocatalytic activity of the nanoparticles was investigated. The synthesized Fe3+-doped TiO2 nanoparticles were analyzed by field emission scanning electron microscopy, transmission electron microscope, powder X-ray diffraction and dynamic light scattering. The nanoparticles had irregular shapes, and the primary size of particles was approximately 100 nm. Though the Fe3+-doping did not change the crystal structure of TiO2, but it had significant affect on their photocatalytic properties. 0.5 % Fe3+-doped TiO2 had the best photocatalytic performance. The particle size of Fe3+-doped TiO2 samples also influenced its photocatalytic activity.
Keywords: Photocatalytic property, Titanium dioxide, Iron doping, Acid red, Nanoparticles
The present research work deals with the assessment of water pollution due to shipbreaking activities and its impact on the coastal zone of Chittagong, Bangladesh. In order to study the different physicochemical parameters, water samples from thirty Ship-breaking yards were collected and analyzed during the hydrological year 2011-2012. The laboratory findings were compared with the recommended values set by Department of Environment (DoE), and standard calculated on the BSTI and WHO value. Some parameters recorded as higher value compare to the international permissible limits in water. The study reveals that pollutants due to ship-breaking are highly toxic in nature. This affects not only the aquatic environment and human beings of the surroundings but also poses a serious threat to ground and surface water resources of the adjoining areas and the coastal environment of Chittagong region. Also it is indicated that the water of ship breaking yards are continuously polluting the Bay of Bengal and the rivers of Chittagong, especially the water of Karnafuli River is being polluted greatly. The polluted water of the Karnafuli River may affect the biodiversity of the Halda River. Though Ship-breaking has earned a good reputation for being a profitable industry in developing countries it could be said that, the ship breaking operation involves serious environmental and human health hazards. It is one of the manmade hazards in the coastal region of Bangladesh.
Keywords: Physicochemical assessment, water pollution, ship-breaking activities, Chittagong region
The physicochemical assessment study was carried out to assess the soil quality in Ship-breaking yards of Chittagong region, Bangladesh. In order to study the different physicochemical parameters, soil samples from thirty Ship-breaking yards were collected and analyzed during the period 2011-2012. Collected soil samples were analyzed for the following parameters: pH, EC, soil salinity, nitrogen, potassium, chloride, phosphate, nitrate, nitrite, cadmium, chromium, arsenic, cobalt, copper, iron, lead, manganese, nickel, silver and zinc using the procedure outlined in the standard methods. The laboratory findings were compared with the recommended values set by the control area and standard calculated on the World Scale. The ranges of different physicochemical parameters obtained are as follows: pH: 4.17-6.92, EC: 1722-5600 μS cm-1, soil salinity: 16651.7-54152, N: 115-1205 mg kg-1, K: 693.75-812.45 mg kg-1, chloride: 1900-7500 mg kg-1, phosphate: 8.36-34.84 mg kg-1, nitrite: 0.03-8.41 mg kg-1, nitrate: 0-74.05 mg kg-1, iron: 1250-10057 mg kg-1, manganese: 0-158.90 mg kg- 1, chromium: 0.6-65.2 mg kg-1, cobalt: 5.75-24.45 mg kg-1, nickel: 16.30-162.2 mg kg-1, copper: 0-295.65 mg kg-1, zinc: 33.25-305.10 mg kg-1, silver: 4.60-132.45 mg kg-1, cadmium: 0.55-3.95 mg kg-1, lead: 0-137.05 mg kg-1, arsenic: 0.0152-0.9505 mg kg-1. Soil nutrients like N, K were found in the level below that of the control area and standard calculated on the World Scale. Trace and heavy metals like Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were found very much higher than the control area and standard values set by World Scale. The anion like nitrate, nitrite, phosphate for which no standard values are recommended by World Scale are also not in good conditions and the concentration of chloride was very higher than the control area and the standard. From Pearson Correlation program, significant positive and negative correlations were found for different parameters. These assessment data indicated that the soil of Ship-breaking yards in Chittagong region are highly polluted which are continuously polluting the Coastal Zone, sea and the rivers of Chittagong, especially the water of Karnafuli River is being polluted greatly. The polluted water of the Karnafuli River may affect the biodiversity of the Halda River. Results from this study show that discharges from the broken Ships are highly toxic in nature. This affects not only the soil, aquatic environment and human beings of the surroundings but also poses a serious threat to ground and surface water resources of the adjoining areas and coastal zone of Chittagong, Bangladesh.
Keywords: Physicochemical assessment, soil pollution, Ship-breaking area in Chittagong region, Bangladesh
In the present study, agricultural waste Zea maize leaves powder (MLP) was used for the removal of cadmium (II) from the aqueous solutions. The adsorption characteristics of maize leaf as a function of pH (2-7), adsorbent dose (0.2-0.5 g), temperature (20-30oC), contact time (0-120 min) and initial metal concentration (1-15 mg L-1) were studied. The biosorption of cadmium (II) on MLP was dependent on pH, adsorbent dose, temperature, contact time and initial metal concentration .The experimental results were analyzed in terms of Langmuir and Freundlich isotherm models. The Fourier Transform Infrared (FTIR) measurements reveal that the presence of hydroxyl, amino and carboxylic functional groups on the surface of MLP which provide the major biosorption sites for the metal binding. The results obtained could be useful for the application of agricultural wastes for heavy metal removal from the industrial waste water.
Keywords: Bioremediation; Cadmium (II); Agricultural wastes; Adsorption isotherms; FT-IR; Wastewater
Nano coatings are materials that are produced by shrinking the material at the molecular level to form a denser product. Nano coatings have several advantages such as better surface appearance, good chemical resistance, better thermal and electrical conductivity and better corrosion resistance. Incorporation of nanoparticles enhance the corrosion resistance of zeolite coatings, epoxy coatings and antimicrobial coatings.
Keywords: Nano particles, nano coatings, Zeolite coatings, epoxy coatings, antimicrobial coatings, corrosion inhibition
Biochemistry, molecular biology and biotechnology
The present study was aimed to integrate genotoxicity test with routine toxicity test in 28 days repeated dose oral toxicity of Marrakesh’s wastewater in mice. Wastewater was administered at the dose of 25%, 50% and 75% per oral repeatedly for 28 days in mice. The endpoints of evaluation for routine toxicity testing included body weight (BW), organ weight (OW), food intake (FI), water intake (WI), hematology (HE) and histology (HI), while for the genotoxicity testing micronucleus (MN) and chromosomal aberration (CA) assay were used. The body weight (BW) significantly decreased at the highest dose of wastewater treatment as compared to the control group. Histological data (HI) revealed morphological alterations in the liver and lung cells at the highest dose of wastewater treatment. Micronucleus (MN) assay results indicated that the highest dose of wastewater led to a significant increase as compared to the control group. Chromosomal aberration (CA) assay results indicate significant DNA damage in different organs induced by wastewater as compared to the control group. Integration of a genotoxicity test with routine toxicity test would reduce the cost of additional animals and test items, while also providing further information at an early stage of product development.
Keywords: wastewater; DNA; mitosis; micronucleus cell; genotoxicity
Selenium plays important roles in antioxidant defence systems, prevents cell damage and is necessary for growth, fertility, and immune system in farm animals. Recently, nano-elemental Se has attracted wide spread attention due to its high bioavailability and low toxicity, because nanometer particulates exhibit novel characteristics, such as great specific surface area, high surface activity, a lot of surface active centres, high catalytic efficiency and strong adsorbing ability and over and above the character of low toxicity of Se0. Nano-Se had similar or higher bioavailability and much less toxicity in broiler chicken and goat as compared to selenite, while in contrast some studies suggested that nano-Se was more toxic than selenite to Medaka fish. Feeding trials have proven that nano-Se supplementation had a positive impact on the growth, feed efficiency of the rumen, fertility and on the antioxidant status of the animals. However, the bioactivity of nano-Se depends on the size, while heat treatment has measurable effect on the size, structure, and bioactivity of selenium nanoparticles. This suggests that if extensive heat exposure is unavoidable during the feed processing, smaller sized selenium nanoparticles should be used. A basic understanding of the absorption, distribution, and clearance and the whole metabolic pathways and mechanisms of nano-Se should be modelled and next to this the understand of negative effects should be investigated and demonstrated in parallel with the novel, promising characteristics as well before using it in common in the animal nutrition.
Keywords: nano-elemental selenium, selenite, farm animals, selenium toxicity
Understanding of the mechanisms lying in the changes of the cardiomyocyte (CMC) subsarcolemma (SS) will give opportunities for searching the medicaments assuring maximal protection of cells. In this study, for the first time, we demonstrated coronary arterial disease (CAD) and mitral valve defect (MVD) influence on the myocardium leading to the alterations of CMC SS cytoskeleton thickness. The alterations of SS structures as well as the mitochondria of cells could be one of the main reasons leading to postsurgical damages of cardiomyocytes.
Keywords: Transmission electron microscopy (TEM), coronary arterial disease, mitral valve defect, subsarcolemmal structures, cytoskeleton
Industrial and engineering chemistry
A detailed analysis was undertaken to determine the physico-chemical characteristics and pollution level in the sample collected from one of the distillery situated in the area of Unnao, India. The samples were collected from a fixed spot of the distillery in one year duration from Jan 2011 to Dec. 2011 at monthly interval. Presence of high chemical load like iron, calcium, magnesium, carbonate, bicarbonate, chloride, BOD, COD etc. were observed in the discharged effluent of the above stated distillery. High variations were observed according to monthly level and results showed that there are certain relationships between physico- chemical characteristics of effluents of both positive and negative.
Keywords: characterization of distillery effluents, chemical and biological oxygen demand (BOD, COD), total dissolved solids (TDS) content, wastewater analysis, pollution level, correlation of wastewater parameters
The corrosion inhibition of a inhibitor namely nickel complex of 1-(8-hydroxyquinolin-2yl-methyl)thiourea (Ni-HTF) in controlling corrosion of mild steel immersed in aqueous solution containing 60 ppm Cl- has been investigated electrochemically and weight loss method. The formulation consisting of 60 ppm of Cl- and 50 ppm of Ni-HTF offers good inhibition efficiency of 80 %. AC impedance spectra reveal that a protective film is formed on the metal surface. Fluorescence spectral analysis was used to detect the presence of ironinhibitor complex. The surface morphology has been analyzed by FTIR spectroscopy.
Keywords: Corrosion inhibition, mild Steel, AC impedance, FTIR, fluorescence, transition metal complex