European Journal of Chemistry

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ISSN / EISSN : 2153-2249 / 2153-2257
Current Publisher: European Journal of Chemistry (10.5155)
Total articles ≅ 917
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European Journal of Chemistry, Volume 11, pp 298-303; doi:10.5155/eurjchem.11.4.298-303.2032

In this work, two types of azobenzene derivatives based on Disperse Yellow 7 (DY7, 4-[4-(phenylazo)phenylazo]-o-cresol) were synthesized, which are bis-azobenzenes bearing flexible functional 6-bromohexyl chain or carboxylic acid moiety. The first one was synthesized by alkylation of DY7 with an excess of 1,6-dibromohexane in the presence of a mild base (K2CO3). The second one (azo dye with carboxylic acid functionality) was obtained by the alkaline hydrolysis of the ester bond of the newly obtained DY7 derivative with the ethoxycarbonyl group. The synthesized compounds were characterized by different spectral analytical techniques such as 1H NMR, 13C NMR, FT-IR, and UV-Vis. They can be employed for the synthesis of a wide variety of azo-based materials, which may be suitable for photochromic systems and molecular electronics applications.
European Journal of Chemistry, Volume 11, pp 324-333; doi:10.5155/eurjchem.11.4.324-333.2028

A combined theoretical and experimental investigation on a pharmaceutically important binary complex 3,3'-[(3-benzimidazolyl)methylene]bis(4-hydroxy-2H-1-benzopyran-2-one): 5-methyl-1,3-thiazol-2(3H)-imine is presented in this manuscript. The compound crystallizes in the monoclinic crystal system with space group Cc with unit cell parameters: a = 19.8151(8) Å, b = 15.2804(6) Å, c = 8.3950(4) Å, β = 94.0990(10)°, V = 2535.36(19) Å3, Z = 4, T = 296(2) K, μ(MoKα) = 0.184 mm-1, Dcalc = 1.490 g/cm3, 35833 reflections measured (5.332° ≤ 2Θ ≤ 56.678°), 6168 unique (Rint = 0.0467, Rsigma = 0.0388) which were used in all calculations. The final R1 was 0.0435 (I > 2σ(I)) and wR2 was 0.1073 (all data). The crystal structure has been determined by the conventional X-ray diffraction method, solved by direct methods and refined by the full matrix least squares procedure. Intramolecular hydrogen bonding of the type C–H⋅⋅⋅O and O–H⋅⋅⋅O is present and the crystal structure stabilizes via N–H…O, C–H…N and O–H…N intermolecular interactions. The optimized structural parameters have been compared and the parameters like ionization potential, electron affinity, global hardness, electron chemical potential, electronegativity, and global electrophilicity based on HOMO and LUMO energy values were calculated at B3LYP/6-311G(d,p) level of theory for a better understanding of the structural properties of the binary complex.
Jahangir Mondal, Amit Kumar Manna , Goutam K. Patra
European Journal of Chemistry, Volume 11, pp 334-341; doi:10.5155/eurjchem.11.4.334-341.2037

Three new halide bridged copper(I)complexes [Cu2(µ-L)(µ-X)2)(PPh3)2]n {X: I (1), Br (2) and Cl (3)} have been synthesized by the reaction of Cu(I)X (X: I, Br and Cl) with PPh3 and the polydentate imino-pyridyl ligand L. Interestingly, copper(I) forms coordination polymers with the ligand L and the co-ligand PPh3. These complexes 1, 2 and 3 have been characterized by elemental analysis, IR, UV-Vis, and NMR spectroscopy. The crystal structure of the complex 2 has been determined by single-crystal X-ray analysis. Crystal data for complex 2: triclinic, space group P-1 (no. 2), a = 9.471(10) Å, b = 11.043(11) Å, c = 13.215(18) Å, α = 65.853(18)°, β = 69.94(2)°, γ = 67.350(14)°, V = 1135(2) Å3, Z = 2, T = 296.15 K, μ(MoKα) = 2.806 mm-1, Dcalc = 1.535 g/cm3, 4059 reflections measured (3.462° ≤ 2Θ ≤ 44.818°), 2639 unique (Rint = 0.0637, Rsigma = 0.1621) which were used in all calculations. The final R1 was 0.0700 (I > 2σ(I)) and wR2 was 0.2207 (all data). Hirshfeld surface analysis of the complex 2 showed H···H, N···H and Br···H interactions of 55.9, 14.4 and 4.1%, respectively. MEP of ligand L reflects the whole molecule is reddish yellow in color because of equally distributed electron density over the molecule. For this reason, the ligand is supramolecularly arranged via -{CuI2-µ-X2} rhomboid core in the complex 2. The ligand L is non-emissive at room temperature in dichloromethane, whereas the complexes 1, 2 and 3 are photoluminescent. DFT and Hirshfeld surface studies have also been performed for complex 2.
European Journal of Chemistry, Volume 11, pp 342-350; doi:10.5155/eurjchem.11.4.342-350.2045

A preliminary study to provides insight into the kinetic and thermodynamic assessment of the reaction mechanism involved in the non-oxidative dehydrogenation (NOD) of propane to propylene over Cr2O3, using a density functional theory (DFT) approach, has been undertaken. The result obtained from the study presents the number of steps involved in the reaction and their thermodynamic conditions across different routes. The rate-determining step (RDS) and a feasible reaction pathway to promote propylene production were also identified. The results obtained from the study of the 6-steps reaction mechanism for dehydrogenation of propane into propylene identified the first hydrogen abstraction and hydrogen desorption to be endothermic. In contrast, other steps that include propane’s adsorption, hydrogen diffusion, and the second stage of hydrogen abstraction were identified as exothermic. The study of different reaction routes presented in the energy profiles confirms the Cr-O (S1, that is, the reaction pathway that activates the propane across the Cr-O site at the alpha or the terminal carbon of the propane) pathway to be the thermodynamically feasible pathway for the production of propylene. The first hydrogen abstraction step was identified as the potential rate-determining step for defining the rate of the propane dehydrogenation process. This study also unveils that the significant participation of Cr sites in the propane dehydrogenation process and how the Cr high surface concentration would hinder the desorption of propylene and thereby promote the production of undesired products due to the stronger affinity that exists between the propylene and Cr-Cr site, which makes it more stable on the surface. These findings thereby result in Cr-site substitution suggestion to prevent deep dehydrogenation in propane conversion to propylene. This insight would aid in improving the catalyst performance.
Amadou Diop , Serigne Omar Sarr , Awa Boubou Sall, Ousmane Niass , Bara Ndiaye, Yerim Mbagnick Diop
European Journal of Chemistry, Volume 11, pp 364-369; doi:10.5155/eurjchem.11.4.364-369.2046

Cucurbits are largely grown in tropical and subtropical areas for nutritional and medicinal purposes. In Senegal, two species, watermelon (Citrullus lanatus) and pumpkin (Cucurbita pepo), are cultivated and their use include consumption of flesh or the whole fruit. In general, people don’t give importance to seeds which can have nutritional properties of great interest. Hence, the relevance of this study whose objective is to assess the nutritional and therapeutic properties of seeds. For that purpose, the seeds of watermelon and pumpkin were air-dried, manually shelled, ground, and subjected to assays including physicochemical determination, characterization of oils, phytochemical screening and antioxidant analysis. Proteins (28.46 - 32.85 %), fat (36.3 - 39.7 %) and carbohydrates (23.6 - 13.9 %) were the main chemical components found in watermelon and pumpkin seeds. Micro-elements such as potassium, magnesium, phosphorous, calcium, and iron were also found with potassium showing the highest levels as 1026.07 and 635.00 mg/100 g for watermelon and pumpkin, respectively. Magnesium and phosphorous were the following minerals in terms of level content. The unsaturated fatty acids (UFAs) were predominant in seed oils with the linoleic acid most representative as 73.01 and 35.90% for watermelon and pumpkin, respectively. From the saturated fatty acids (SFAs), the palmitic acid was the most important. Phytochemical components in seeds include the presence of alkaloids, cardiac glycosides, flavonoids, and tannins in the ethanolic extracts of pumpkin and watermelon seeds. Regarding to the radical scavenging activity, relatively close values have been obtained for fractions from the ethanolic watermelon extract, the aqueous fraction showing the highest antioxidant activity (26.82%). For pumpkin, the highest values were registered for ethyl acetate and aqueous fractions as 36.17 and 35.36%, respectively. Therefore, seeds from watermelons and pumpkin cultivated in Senegal exhibited interesting nutritional and antioxidant properties which argue in favor of their use to overcome malnutrition issues.
European Journal of Chemistry, Volume 11, pp 370-376; doi:10.5155/eurjchem.11.4.370-376.2048

This study reports on the chemical compositions of the essential oil of Rosmarinus officinalis L. (Rosemary) grown in Mersin, Turkey. The essential oil of rosemary was obtained by hydrodistillation method, and the yield of rosemary oil was found to be about 1.2 % (v:w). The hydrodistilled volatile oil was analyzed by gas chromatography and mass spectrometry techniques. Forty-five components were identified in the essential oil of R. officinalis, which represented 100% of the total essential oils. The oxygenated monoterpenes content possessed the highest value, 64.78% of the oil, among which eucalyptol (33.15%) and camphor (10.31%) were the most abundant components. In addition, the oil contained mainly monoterpene hydrocarbons, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and diterpenes. The least amount of diterpenes were found in the content of the oil. Isopimara-9 (11),15-diene (0.14%) and α-springene (0.06%) were two compounds determined as diterpene compounds.
European Journal of Chemistry, Volume 11; doi:10.5155/eurjchem.11.4.i-ii.2052

European Journal of Chemistry, Volume 11, pp 280-284; doi:10.5155/eurjchem.11.4.280-284.2010

Ziprasidone (ZPR) is an antipsychotic agent having less solubility. It is used for the treatment of schizophrenia. Complexation of hydrophobic drugs with cyclodextrins leads to enhanced solubility and dissolution. In this study, inclusion complexes were prepared by different methods, using ZPR, β-cyclodextrin (β-CD), and different auxiliary agents like hydrophilic polymer and hydroxy acid (1:1:0.5) to improve the aqueous solubility. The characterization of the ternary complexes was carried out using solubility study, Differential scanning calorimetry (DSC), Powder X-ray diffraction (PXRD), Fourier transformation infrared spectroscopy (FT-IR) and in vitro dissolution studies. DSC, XRD, and FT-IR studies showed interaction in drug, cyclodextrin, and auxiliary agents which are confirmed by enhancement of solubility and dissolution. Spray-dried dispersion showed less crystallinity and higher solubility as compared to the kneading method for both citric acid and Lutrol® F-68. Thus, the investigation concludes that the presence of the auxiliary agent has a synergistic action on complexation with cyclodextrin, which helps to modify the physicochemical properties of the drug.
European Journal of Chemistry, Volume 11, pp 285-290; doi:10.5155/eurjchem.11.4.285-290.2023

Carbonohydrazide was used for synthetizing a new dissymmetrical bis-substituted Schiff base 1-(2'-hydroxybenzylidene)-5-(1'-pyridylethylidene)carbonohydrazone (2). A mono substituted compound (1-(pyridin-2-yl)ethylidene)carbonohydrazide (1) was firstly prepared by condensation reaction of carbonohydrazide and 2-acetylpyridine in 1:1 ratio. Secondly, compound 2 was obtained by condensation reaction of compound 1 and salicylaldehyde in 1:1 ratio. The prepared compounds were characterized by elemental analysis, infrared and 1H and 13C NMR spectroscopy techniques, and the structure of compound 2 was determined by single-crystal X-ray diffraction study. The compound 2 (C15H15N5O2) crystallises in the monoclinic space group P21/c with the following unit cell parameters: a = 8.3683(3) Å, b = 13.9986(4) Å, c = 12.1610(4) Å, β = 97.512(3)°, V = 1412.37(8) Å3, Z = 4, T = 100(2) K, μ(MoKα) = 0.098 mm-1, Dcalc = 1.398 g/cm3, 6057 reflections measured (5.708° ≤ 2Θ ≤ 54.962°), 6057 unique (Rsigma = 0.0395) which were used in all calculations. The final R1 was 0.0474 (I > 2σ(I)) and wR2 was 0.1971 (all data). The oxygen atom O1 and the azomethine nitrogen atom N5 adopt cis-configuration relative to the C8-N4 bond, while O1 adopts trans-configuration with the azomethine nitrogen atom N2 relative to C8-N3 bond. The crystal packing of compound 2 is stabilized by intramolecular O(phenol)–H···N(carbohydrazide) and intermolecular N (carbohydrazide)–H···O (carbo-hydrazide) hydrogen bonds which form layers parallel to [010] axis. Additional C–H···O hydrogen bond consolidate the structure. The carbonohydrazide moiety C=N–N–C(O)–N–N=C fragment and the phenyl ring are almost coplanar; with an angle of 1.73(1)° between their means plans. The dihedral angle between the mean planes of the phenyl and the pyridine rings is 22.267(2)°.
European Journal of Chemistry, Volume 11, pp 261-275; doi:10.5155/eurjchem.11.4.261-275.2020

2-Chloro-3-tosyl-5,5-dimethyl-2-cyclohexenone was subjected to a series of regiospecific Suzuki-Miyaura cross-coupling reactions in suspensions of nine different substituted boronic acids, Pd(OAc)2, P(Ph3)3, K3PO4 and 1,4-dioxane solvent, under sealed tube conditions. The regiospecific substitution of the tosyl-group by the aryl group in preference over the chloride- group was observed. A comparison between the bromo- and tosylate group’s reactivities is highlighted. Using the methodology, the products: 2-chloro-3-aryl-5,5-dimethyl-2-cyclohexenones were isolated in greater than 85% yields. Good quality crystals of three representative compounds were obtained by slow evaporation technique and subjected to single crystal XRD studies, Hirshfeld surface analysis, 3-D energy framework, and molecular docking studies. Crystal data for compound 3; C15H17ClO4S: monoclinic, space group P21/c (no. 14), a = 8.8687(3) Å, b = 10.5537(4) Å, c = 16.6862(7) Å, β = 89.807(3)°, V = 1561.78(10) Å3, Z = 4, T = 290 K, μ(MoKα) = 0.390 mm-1, Dcalc = 1.398 g/cm3, 13623 reflections measured (6.716° ≤ 2Θ ≤ 54.962°), 3570 unique (Rint = 0.0467, Rsigma = 0.0512) which were used in all calculations. The final R1 was 0.0452 (I > 2σ(I)) and wR2 was 0.1019 (all data). Crystal data for compound 5e; C20H18O2FCl: monoclinic, space group P21/c (no. 14), a = 6.4900(5) Å, b = 18.6070(13) Å, c = 14.2146(11) Å, β = 102.324(2)°, V = 1677.0(2) Å3, Z = 4, T = 296(2) K, μ(MoKα) = 0.239 mm-1, Dcalc = 1.309 g/cm3, 25575 reflections measured (6.262° ≤ 2Θ ≤ 52.224°), 3283 unique (Rint = 0.0494, Rsigma = 0.0307) which were used in all calculations. The final R1 was 0.0875 (I > 2σ(I)) and wR2 was 0.2056 (all data). Crystal data for compound 5h; C12H13OSCl: triclinic, space group P-1 (no. 2), a = 6.7517(6) Å, b = 8.8376(9) Å, c = 12.6049(12) Å, α = 109.538(3)°, β = 98.597(3)°, γ = 90.417(3)°, V = 699.52(12) Å3, Z = 2, T = 290 K, μ(MoKα) = 0.410 mm-1, Dcalc = 1.376 g/cm3, 28754 reflections measured (6.114° ≤ 2Θ ≤ 59.288°), 3898 unique (Rint = 0.0544, Rsigma = 0.0349) which were used in all calculations. The final R1 was 0.1101 (I > 2σ(I)) and wR2 was 0.2481 (all data).
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