European Journal of Chemistry

The reaction between 5-nitroisatin with S-benzyl dithiocarbazate affords a new isatindithio carbazate so-called NO₂Isadtc (Benzyl 2-(5-nitro-2-oxoindolin-3-ylidene)hydrazinecarbodi thioate) which was characterized by means of ¹H NMR, FT-IR, UV-visible and single crystal X-ray diffraction - Crystal data for C₁₆H₁₂N₄O₃S₂ (M =372.42 g/mol): triclinic space group P-1, (n°. 02), a = 6.640 Å, b = 8.256 Å, c = 15.908 Å, V = 849.6 ų, Z = 2, T = 293 K, μ(MoK_α) = 0.337 mm^-1, D_calc = 1.456 g/cm³, 27515 reflections measured (2.499° ≤ 2Θ ≤ 26.524°), 3518 unique (R_int = 0.0533, R_sigma =0.0222) which were used in all calculations. The final R₁ was 0.0367 (I > 2σ(I)) and wR₂ was 0.1045 (all data). Computational methods were applied to NO₂Isadtc and its nonsubstituted parent compound Isadtc for structure optimization, electronic distribution, and infrared calculations using B3LYP functional with 6-31G(d,p) basis set in ethanol as a polarizable continuum model. Furthermore, docking studies using human thioredoxin reductase 1 (TrxR) as enzyme target also were performed using NO₂Isadtc and the optimized structure of Isadtc. The results demonstrated that both NO₂Isadtc and Isadtc may act as inhibitors of TrxR, having different interactions detected, highlighting the contact between the NO₂ group and the S111 at the helix which is found for NO₂Isadtc.

Promoting the green technology campaign that would actualize a biorefinery establishment and would promote cleaner fuel production and air in our environment. This study carried out kinetics studies of biodiesel production over a mixed oxide, Ca-Mg-O catalyst, providing relevant kinetics parameters. This study indicated that biodiesel production is a zero-order reaction, a process independent of the concentration. The results obtained from this study confirm the activation energy, E_a, of the reaction to be 406.53 J/mol, while the pre-exponential factor A was found to be 0.01618 1/min (or 0.9 1/h). Other are kinetics models that were developed for the prediction of the reaction kinetics for the production process is also reported in this study. The findings reported in this study would go a long way to facilitate the modeling, simulation, and design of the biodiesel production process.

The synthesis and characterization of an imino-pyridyl ligand N,N'-(butane-1,4-diyl)bis(1-(pyridin-2-yl)methanimine) (L) and its Ag(I)ClO₄ complex (I) by various spectroscopic techniques and elemental analyses is presented in this study. X-ray single crystal structure of complex I revealed that in complex I, each Ag(I) ion is tetra coordinated with two pyridine N-atoms and two imine N-atoms of the ligand L, forming a macrocyclic dimeric Ag(I) grid. In the macrocyclic dimer complex I, Ag-Ag separation along the chain is 5.318 Å. The Ag-N_py average distance is 2.396 Å and that of the Ag-N_im is 2.257 Å. The macrocyclic dimer complex I is supramolecularly arranged by π-stacking interactions. Computational, Hirshfeld surface analysis and photophysical studies on ligand L and complex I have also been performed. Crystal data for C₃₂H₃₆Ag₂Cl₂N₈O₈ (M =947.33 g/mol): Triclinic, space group P-1 (no. 2), a = 9.1714(12) Å, b = 10.4373(14) Å, c = 10.8297(14) Å, α = 112.317(3)°, β = 91.391(3)°, γ = 92.353(3)°, V = 957.3(2) Å³, Z = 1, T = 293.15 K, μ(MoKα) = 1.220 mm^-1, Dcalc = 1.643 g/cm³, 10248 reflections measured (4.07° ≤ 2Θ ≤ 53.098°), 3966 unique (R_int = 0.0280, R_sigma = 0.0331) which were used in all calculations. The final R₁ was 0.0722 (I > 2σ(I)) and wR₂ was 0.2229 (all data).

A new Schiff base, N'-(pyridin-3-ylmethylene)benzenesulfonohydrazide, was synthesized and characterized by elemental analysis, IR, Mass, ¹H NMR and ¹³C NMR spectroscopy, and single-crystal X-ray determination. The asymmetric molecule crystallized in the monoclinic crystal system and P2(1)/c space group. Crystal data for C₁₂H₁₁N₃O₂S: a = 9.7547(4) Å, b = 9.8108(4) Å, c = 13.1130(5) Å, β = 109.038(2)°, V = 1186.29(8) Å³, Z = 4, μ(MoKα) = 0.270 mm^-1, Dcalc = 1.463 g/cm³, 13338 reflections measured (5.296° ≤ 2Θ ≤ 55.484°), 2790 unique (R_int = 0.0494, R_sigma = 0.0400) which were used in all calculations. The final R₁ was 0.0345 (I > 2σ(I)) and wR₂ was 0.0914 (all data). In the crystal structure of the compound C₁₂H₁₁N₃O₂S, molecules are linked in a continuous chain by intermolecular of N∙∙∙HN=N hydrogen bonds. The pyridine moiety is planar, while the benzenesulfonohydrazide group adopts a gauche conformation about C-S-N angle (105.54°). The Hirshfeld surface analysis and fingerprint plots were used to establish the presence, nature, and percentage contribution of the different intermolecular interactions, including N-H∙∙∙N, C-H∙∙∙O, C-H∙∙∙C, and π∙∙∙π interactions, with the C-H contacts having the most significant contribution. The pairwise interaction energies were calculated at the B3LYP/6-31G(d,p) level of theory, and interaction energy profiles showed that the electrostatic forces had the most significant contribution to the total interaction energies of the different molecular pairs in the crystal. In-silico technique was used to examine the compound as a possible anticancer agent. The molecule demonstrated zero violation of the criteria of Lipinski’s rule of five with a polar surface area of 116.03 Ų. The molecule displayed favorable binding interactions with ten selected validated anticancer protein targets ranging from -9.58 to -11.95 kcal/mol and -2.73 to -5.73 kcal/mol on scoring and rescoring, respectively, with London dG and Affinity dG scoring functions. Two proteins; farnesyl transferase and signaling protein, preferred interactions with the Schiff-base over their co-crystallized inhibitors according to London dG scoring. Analysis of binding poses indicated that the Schiff-base made contact with amino acid residues of the two proteins through the N-H, sulphonyl oxygen, and phenyl groups, and this could be exploited in chemical and structural modification towards activity optimization.

Simple and precise spectrophotometric methods for quantitative assay of a mixture of hydrocortisone acetate (HCA) and clioquinol (CL) were developed and validated through different mathematical manipulation pathways. The developed methods utilized ratio spectra for resolving binary mixtures including absorbance subtraction, ratio subtraction coupled with spectrum subtraction, constant multiplication, constant value, and derivative ratio. The proposed methods were proved to be specific by analysing the laboratory-prepared mixtures and were applied for the assay of topical preparation successfully. The methods were validated using ICH guidelines where accuracy, repeatability and intermediate precision were within the acceptable limits. The linearity range was found to be 2-22 for HCA and 1.5-7 µg/mL for CL in all proposed methods and 2-7 µg/mL for HCA and CL in absorbance subtraction method through using a unified regression equation. The findings were statistically evaluated with respect to the official and reported methods, demonstrating that there was no significant difference.

Caking formation in fertilizer products during handling and storage is a frequently encountered problem. Caked fertilizers become together as lumps, lose their free- flowing properties, and create inefficient applications. Several parameters such as relative humidity and temperature of the environment, pressure by pile height, and physicochemical properties of fertilizer product such as moisture content, presence of fines and chemical composition, etc. cause or accelerate caking mechanism. Internal or external anticaking products have been proved to be effective in preventing the caking of fertilizer particles. Liquid or wax anticaking agents are applied externally as coatings on the fertilizer surface. This study focuses on the performance evaluation of commercially available liquid- wax anticaking agents coated on NP 20-20-0 fertilizer, classified as three main groups: petroleum-derived, alkyl amine-fatty acid containing mixtures and bio- based composition. Caking performance of coating products are evaluated via small-bag storage test in 4 sets, according to the results, petroleum derived and alkyl amine- fatty acid containing anticaking products show similar performance, whereas bio-based products’ performance is moderate. This study focuses on a practical approach that will help fertilizer industry about which type of coating product will be effective on the anticaking properties of nitrogenous fertilizers and gives brief results of the effect of commercially available products with various ranges of chemical composition on the caking process.

This research work describes the synthesis of a new series of heterocyclic compounds, namely sulfonamide derivatives. Sulfonamides are a diverse class of organic compounds having significant and potent biological activities. Diverse synthetic methods have been engaged to build up its various derivatives for different biological functions. In this study, the production of novel pyridine-based heterocyclic compounds having sulfonamide moieties has been elaborated. The obtained sulfonamide-based pyridine scaffold was used to investigate their alpha-amylase inhibition activity. The structures of freshly prepared compounds were described using ¹H NMR, ¹³C NMR, and IR spectroscopic techniques. The molecular docking of sulfonamides performed against porcine pancreatic alpha-amylase using PDB file 1LP was used for generation of grid. All the new synthesized compounds were shown notable anti-diabetic activity.

Caffeine is naturally present in tea and coffee giving the pleasant and stimulant effect. Several different types of teas, black, green, and white teas bought in market were analysis for caffeine content. The boiled sample tea was filtered through filter paper. Lead(II) acetate was used to separate tannins from caffeine followed by filtration through filter paper with a black ribbon. The liquid-liquid extraction was carried out using dichloromethane (3×5 mL) and sodium sulfate as a drying agent. The TLC method was performed on Merck precoated silica gel plates 5×10 cm (60F₂₅₄, 200 μm) using either methanol or dichloromethane as solvents and the mobile phases were glacial acetic acid and ethyl acetate (95:5, v/v), while the second one was consisted of ethyl acetate and ethanol (80:20, v/v), respectfully. The R_f values were 0.36 and 0.86 for the first and the second mobile phase, respectively, in comparison to the standard caffeine. The values for pH of boiled sample teas were in the range from 4.85 to 5.80. The most abundant tea sample for caffeine was determined in green tea bought in the grocery store for health nutrition (2.04 %). The yield for tea samples from green market, white tea and two tea black samples were 0.06, 0.71, 0.07, and 0.05%, respectively. The developed TLC method can be used for determination of caffeine content in tea samples.

Caffeine is a refractory pollutant of emerging concern that evades conventional waste-water treatment techniques. Here, we report the synthesis of visible light responsive perovskite structured LaMnO­₃ photocatalyst using modified Pechini method and utilized it as an efficient photocatalyst for caffeine degradation. XRD, BET, UV-Vis, NH₃-TPD, and SEM were used to characterize the photocatalyst. Response surface methodology using Central composite design was used to investigate the effect of three operational variables; catalyst dosage, initial caffeine concentration and pH on the caffeine photocatalytic degradation efficiency. The functional relationship between these operational variables and caffeine photocatalytic degradation efficiency was established be a second order polynomial model. The results of the response surface analysis indicate caffeine degradation efficiency is most significantly affected by catalyst dosage and pH. The optimal values of operational obtained by response surface optimization were found be 3.5 g/L for catalyst dosage, 7.9 and 44.6 mg/L for pH and initial caffeine concentration respectively given the caffeine degradation efficiency of 93.9%.

The crystal structures can reveal detailed information about the overall structure, active site structure, and functional mechanism of enzymes. This study focused on the crystallization of 3-hexulose-6-phosphate synthase from Methylomonas aminofaciens 77a, to produce higher resolution crystals for precise structural characterization. 3-Hexulose-6-phosphate synthase is from Methylomonas aminofaciens 77a (EC 4.1.2.43). It belongs to the orotidine 5'-monophosphate decarboxylase superfamily, and acts as a key enzyme for a ribulose-monophosphate cycle of formaldehyde fixation and detoxification. 3-Hexulose-6-phosphate synthase catalyzes the aldol condensation of formaldehyde with D-ribulose-5-phosphate. For the maximum activity, 3-hexulose-6-phosphate synthase requires Mg²⁺ or Mn²⁺ as ligands. MaHPS crystallized at the concentration of 7 mg/mL and conditions consisting of 0.2 M MgCl₂, 18% PEG 3350 at pH = 7.0.

The compound 2-(4-fluorophenoxy) acetic acid was synthesized by refluxing, 4-fluoro-phenol as a starting material with ethyl chloroacetate in acetone as solvent. The compound crystallizes in the monoclinic crystal system with the space group P2₁/c. Crystal data for C₈H₇FO₃, a = 13.3087(17) Å, b = 4.9912(6) Å, c = 11.6018(15) Å, β = 104.171(4)°, V = 747.21(16) ų, Z = 4, T = 293(2) K, μ(CuKα) = 1.142 mm^-1, Dcalc = 1.512 g/cm³, 8759 reflections measured (13.72° ≤ 2Θ ≤ 130.62°), 1246 unique (R_int = 0.0528) which were used in all calculations. The final R1 was 0.0458 (>2sigma(I)) and wR2 was 0.1313 (all data). The structure was stabilized by C-H···O and C-H···Cg interactions. The intermolecular interactions in the crystal were studied using Hirshfeld surface analysis. 3D energy frameworks were computed to visualize the packing modes. DFT calculations were performed. The FMOs were studied to estimate the kinetic stability and reactivity of the molecule. The MEP surface was generated to investigate the charge distribution and chemical reactive sites in the molecule.

The adsorption energy of the BMSF-BENZ adsorbed complexes was investigated to understand the non-local dispersion interactions, with many other chemical parameters related to this subject like HOMO and LUMO, energy gap, and the time needed for the BMSF-BENZ to be desorbed from the nanotube (recovery time). Our study reveals that Al-CNT is a promising adsorbent for this drug as E_ads of BMSF-BENZ/Al-CNT complexes are -22.09, -38.68, -12.89, -31.01, -27.31, -21.90, and -21.42 kcal/mol in the gas phase on the active atoms of the BMSF BENZ (Br, N₈, N₉, N₅₈, O₃₅, O₄₁, and S), respectively. In addition, the spontaneous and favorable interaction between the BMSF BENZ and all nanoparticles was confirmed by investigating Gibbs free energy and quantum theory of atoms in molecule analysis (QTAIM) so that it can be used as an electrochemical sensor or biosensor. Furthermore, to more visualize the nature of intermolecular bonding and the strength of interaction between the BMSF-BENZ drug molecule and the nanotube, QTAIM has been widely studied in the case of drug delivery purposes.  Al-CNT (4,0) can be extended as a drug delivery system and the work function type sensor.

This study reports an organic salt prepared from an antibacterial drug, levofloxacin and antioxidant γ-resorcylic acid. A simple preparation method leads to a crystal with disordered structure. The idea is to prepare an organic salt comprising of pharmaceutically acceptable acidic and basic components. The salt is characterised by IR, solid state NMR, and single crystal XRD. Crystal data for C₂₅H₂₆N₃O₈F: triclinic, space group P-1 (no. 2), a = 7.0037(8) Å, b = 12.764(3) Å, c = 13.909(3) Å, α = 104.821(4)°, β = 92.039(4)°, γ = 95.334(4)°, V = 1194.6(4) Å³, Z = 2, T = 296(2) K, μ(MoKα) = 0.113 mm^-1, Dcalc = 1.433 g/cm³, 16879 reflections measured (5.048° ≤ 2Θ ≤ 54.186°), 5139 unique (R_int = 0.0663, R_sigma = 0.0975) which were used in all calculations. The final R₁ was 0.1121 (I>2σ(I)) and wR₂ was 0.2505 (all data). SC-XRD analysis shows that the crystal packing is stabilized by strong H-bonding of type N-H···O and comparatively weak interactions of type C-H···O, C-H···π and off-set π···π stacking.

Nanocomposite hydrogels, made by incorporating nanoparticles into a hydrogel matrix, have been developed to fulfill the need for materials with enhanced and predictable mechanical properties and functionality. This review breaks down the process of preparing and characterizing nanocomposite hydrogels and looks at the various applications they can be used for. Through careful selection of the nanoparticle and hydrogel types, as well as the preparation method, the degree of crosslinking and the strength of the intermolecular interactions between the nanoparticles and the hydrogel matrix can be controlled. Once the nanomaterial is prepared, the morphology, gel content, thermal stability, and mechanical properties are investigated. By varying the concentrations of nanoparticles within the hydrogel matrix, nanocomposite hydrogels with optimal functionality and mechanical properties are produced. The optimized nanomaterial can then be used for its intended application(s); here the focus is on applications in the biomedical and dye adsorption fields. With further research, it is predicted that nanocomposite hydrogels will fulfill their potential to be used in practical, everyday applications.

Considering the highly important biological and medicinal properties of naphthofurans, the synthesis of these heterocycles has attracted the interest of medicinal and organic chemists. This review aims to describe the different strategies developed so far for the synthesis of naphthofurans and their applications and the literature reports for the period of 2000 to early 2020. After a brief introduction of the types of naphthofurans and their biological activities, the different synthetic approaches such as chemical and photochemical, methods are described and organized on the basis of the catalysts and the other reagents employed in the syntheses. Some of the reactions have been applied successfully to the synthesis of biologically important compounds.

Retraction notice to “The chemistry of group-VIb metal carbonyls” [Eur. J. Chem. 2012, 3(3), 367-394, doi: 10.5155/eurjchem.3.3.367-394.604]