European Journal of Chemistry
ISSN / EISSN : 2153-2249 / 2153-2257
Current Publisher: European Journal of Chemistry (10.5155)
Total articles ≅ 934
Latest articles in this journal
European Journal of Chemistry, Volume 12, pp 1-12; doi:10.5155/eurjchem.12.1.1-12.2031
A new spectrofluorimetric reagent N-(pyridin-2-yl)-quinoline-2-carbothioamide (PQTA) has been synthesized and characterized. A very simple, ultra-sensitive, and highly selective, and non-extractive new spectrofluorimetric method for the determination of molybdenum at pico-trace levels using PQTA has been developed. This novel fluorimetric reagent PQTA, becomes oxidized in a slightly acidic (0.0025-0.05 M H2SO4) solution with molybdenum (VI) in absolute ethanol to produce a highly fluorescent oxidized product (λex = 300 nm; λem= 377 nm). Constant and maximum fluorescence intensities were observed over a wide range of acidity (0.0025-0.0500 M H2SO4) for the period between 2 min and 24 h. Linear calibration graphs were obtained for 0.001-600 μg/L of Mo having a detection limit of 0.15 ng/L; the quantification limit of the reaction system was found to be 1.5 ng/L and the RSD was 0-2%. A large excess of over 60 cations, anions, and complexing agents like chloride, phosphate, azide, tartrate, oxalate, and SCN- etc. do not interfere in the determination. The developed method was successfully used in the determination of molybdenum in several Certified Reference Materials (Alloys, steel, serum, bovine liver, drinking water, soil, and sediments) as well as in some environmental waters (Potable and polluted), biological fluids (Human blood, urine, hair, and milk), soil samples and food samples (Vegetables, rice, and wheat) solutions containing both molybdenum (VI) and molybdenum (V) ions. The results of the proposed method for assessing biological, food and vegetable samples were comparable with ICP-OES and AAS were found to be in excellent agreement.
European Journal of Chemistry, Volume 12; doi:10.5155/eurjchem.12.1.iii-vi.2112
European Journal of Chemistry, Volume 12, pp 52-55; doi:10.5155/eurjchem.12.1.52-55.2077
Since street drugs are frequently and rapidly modified, in order to circumvent the current laws that make them illicit, it is necessary to fully identify them by single crystal X-ray diffraction; subsequently, ideal powder patterns are computed for rapid identification of additional confiscations, which are mostly available in powder form. Monoacetyl morphine is found in samples of heroin as a by-product of incomplete synthesis, or from degradation of diacetyl morphine caused by heat, humidity, or pH changes. It is formed by the hydrolysis of the acetyl function on the benzene moiety of the morphine ring, thereby inserting an OH moiety at that site. This compound, 6-monoacetyl morphine, is the primary and active metabolite of heroin, rapidly hydrolyzed in the user’s blood. Herein, we describe the structure of 6-monoacetyl morphine, IUPAC name: [(4R,4aR,7S,7aR,12bS)-9-hydroxy-3-methyl-2,4,4a,7,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-7-yl] acetate (A), as the trihydrated hydrochloride, whose structure has not been described previously. Our crystals belong in space group P212121 with cell parameters of a = 6.9367(2), b = 13.0374(3), c = 21.9856(6) Å, V = 1988.30 (9) Å3; its composition is C19H22NO4Cl·3H2O, and Z = 4.0. A full sphere of data was collected at 100 K using CuKα radiation (λ = 1.54178 Å), yielding 3594 unique reflections measured and a final R-factor = 4.1%, with a Flack parameter = 0.05(1).
European Journal of Chemistry, Volume 12; doi:10.5155/eurjchem.12.1.i-ii.2111
European Journal of Chemistry, Volume 12, pp 18-22; doi:10.5155/eurjchem.12.1.18-22.2036
A rapid UPLC-ESI-MS method was developed for simultaneous determination of caffeine and taurine in beverages (energy drinks and soft drinks). The molecular ions of caffeine and taurine were identified in single ion recording mode at m/z 194.98 and 125.86, respectively. The mass spectrometer parameters were optimized as: capillary voltage 3.0 kV, cone voltage 35 V, extractor 3 V, RF Lens 0.1 V, source temperature 150 °C, desolvation temperature 350 °C, nitrogen 600 L/h, LMR1 7.9, HMR1 15.2, IE1 0.30. The mobile phase comprising methanol (0.1% formic acid) (A) and water (5 mM ammonium acetate) (B) was used in gradient mode. The mobile phase components A and B were pumped in 80:20 (v:v) ratio from 0-0.44 min, and then 100% of component A was pumped between 0.45-0.68 min, and at 0.69 min the composition was returned to 80:20 (v:v) ratio of A and B till 2.0 min. Caffeine and taurine were eluted at 0.46 and 0.43 min, respectively. The samples of energy drinks and soft drinks were diluted in a solvent system comprising methanol and water in 80:20 (v:v) ratio. Our investigations showed that soft drinks SD1 and SD2 have 88.8±4.2% and 110.7±3.6% (w:w) caffeine of their labeled claim. The caffeine content in energy drink brands ED1, ED2, ED3, and ED4 was 76.9±2.5, 65.6±3.4, 88.1±12.6, and 89.1±2.8% (w:w) of labeled claims, respectively. While taurine content in ED1, ED2, ED3, and ED4 was 86.5±8.4, 81.3±27.5, 101.9±4.8, and 97.1±0.3% (w:w) of labeled claim, respectively.
European Journal of Chemistry, Volume 12, pp 60-63; doi:10.5155/eurjchem.12.1.60-63.2089
The synthetic leucite silicate framework mineral analogues Cs2XSi5O12 (X = Cu, Cd, Zn) were prepared by high-temperature solid-state synthesis. The results of Rietveld refinement, using 18 keV synchrotron X-ray powder diffraction data collected at low temperatures (8K X = Cu, Zn; 10K X = Cd) show that the title compounds crystallize in the space group Pbca and are isostructural with the ambient temperature structures of these analogues. The structures consist of tetrahedrally coordinated SiO4 and XO4 sharing corners to form a partially substituted silicate framework. Extraframework Cs cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetrahedrally coordinated sites (T-sites).
European Journal of Chemistry, Volume 12, pp 56-59; doi:10.5155/eurjchem.12.1.56-59.2070
Schiff bases are versatile ligands, synthesized via condensation of primary amines with carbonyl compounds. In this study, equimolar amounts of 4-imidazolecarboxaldehyde and thiosemicarbazide were combined and the Schiff base 4-imidazolecarboxaldehyde thiosemicarbazone was prepared as a new bidentate complexing agent. The synthesized ligand was reacted with palladium (II) and platinum (II) ions yielding air-stable complexes. For characterization purpose, infrared spectra, mass spectra, electronic spectra, thermal analysis, proton nuclear magnetic resonance and 13-carbon nuclear magnetic resonance spectra studies were carried out on the obtained complexes and ligand. The characterization data showed that the ligand acts as a bidentate coordinate to the metal ions through azomethine nitrogen and sulfur atoms. An in vitro antimicrobial investigation was also carried out for the free ligand and its metal complexes against four bacteria; Bacillus cereus, Staphylococcus aureus (Gram-positive), Escherichia coli and Salmonella typhimurium (Gram-negative) and one Fungi; Candida albicans, to assess their antimicrobial properties by disc diffusion technique. Antimicrobial activity of the prepared complexes showed higher activity than the free ligand.
European Journal of Chemistry, Volume 12, pp 32-36; doi:10.5155/eurjchem.12.1.32-36.2051
Senegal is affected by a relatively high prevalence of iodine deficiency disorders, which compromises its social and economic development. To address this situation, the Universal Salt Iodization strategy was adopted by the Senegalese Government. The monitoring of salt iodine status is crucial to the success of such a program. Therefore, this study aimed to evaluate the iodine concentration of table salt from Senegalese households. A total of 1575 samples collected in urban and rural areas were analyzed using the iodometric method. The powdered salt samples showed higher mean iodine content (18.99 ppm) and lower percentage of non-compliance (58.4%) than the other salt types (p = 0.02). Most of the samples collected from urban area were found with iodine content between 15 and 39.9 ppm, whereas, in rural areas, the situation was significantly different (p = 0.01). Iodine levels of most samples were lower than 5 ppm in the rural producing area or varied between 5 to 14.9 ppm in the rural non-producing area. A percentage of 37.3% of adequately iodized salt samples was obtained at a national scale with a significant disparity between urban and rural areas. Therefore, improvements in quality control procedures in tandem with the iodization process are necessary and an information, education and communication strategy should be adopted.
European Journal of Chemistry, Volume 12, pp 77-80; doi:10.5155/eurjchem.12.1.77-80.2068
Several studies have reported the presence of amine and imine tautomeric forms for hydrogenated 1,3-thiazine derivatives. However, identification of their tautomeric forms by UV, FTIR and mass-spectral methods does not yield expected results. Here, we report the synthesis of 2-phenylaminodihydro-1,3-thiazine and 2-phenyliminotetrahydro-1,3-thiazine and the analysis of their UV, FTIR and NMR (1H and 13C) spectral data. An identical picture of UV spectra was recorded for both compounds. However, distinctive characteristics were found in the FTIR, 1H and 13C NMR spectra. The C=N band of amine form was observed in higher frequency region relative to imine form. The signal of C2 carbon of amine form in 13C NMR spectrum was occurred in more downfield (δ 165.3 ppm) relative to C2 signal of imine form (δ 152.1 ppm). In addition, the difference between C2 and C8 carbon signals of amine form was very high (Δδ = 30.6 ppm) relative to imine form (δ 5.4 ppm). The position of C2 and C8 signals and the difference between them in 13C NMR spectrum was found to be more promising in identification of tautomeric forms in case of hydrogenated 1,3-thiazine derivatives.
European Journal of Chemistry, Volume 12, pp 13-17; doi:10.5155/eurjchem.12.1.13-17.2035
The development of highly effective and low-toxicity nonsteroidal anti-inflammatory drugs (NSAIDs) is one of the important challenges facing modern pharmacology. To overcome this problem, many studies have been conducted on compounds containing a five-membered heterocycle containing three nitrogen atoms. The pharmacodynamics of these compounds are mainly due to their anti-inflammatory effect. Therefore, it is important to synthesize new derivatives of 1,2,3-triazoles, to determine their structure and to look for substances with anti-inflammatory activity on their basis. For the first time, the corresponding derivatives of 4-(4-(exchangeable)-1H-1,2,3-triazole-1-yl)-benzoic acid were synthesized by cycloaddition of propargyl esters of saturated carboxylic acids and para-azidobenzoic acid in the presence of copper (I) iodide. The structure of the obtained substances was analyzed by IR, 1H NMR, and MS techniques. It is proved that under the action of the catalyst in the reaction, only 1,4-isomers are formed. Factors affecting the course of the reaction were identified. Only one isomer is formed in the reaction of cyclic addition under the action of a catalyst and the effect of temperature, duration of time, and nature of the solvent on the reaction yield was studied.