European Journal of Chemistry

Fluorescence resonance energy transfer (FRET) is a powerful tool used in a wide range of applications due to its high sensitivity and many other advantages. Co-encapsulation of a donor and an acceptor in nanoparticles is a useful strategy to bring the donor-acceptor pair in proximity for FRET. A highly efficient FRET system based on BODIPY-BODIPY (BODIPY:  boron-dipyrromethene) donor-acceptor pair in nanoparticles was synthesized. Nanoparticles were formed by co-encapsulating a green emitting BODIPY derivative (FRET donor, l_max = 501 nm) and a red emitting BODIPY derivative (FRET acceptor, l_max = 601 nm) in an amphiphilic polymer using the precipitation method. Fluorescence measurements of encapsulated BODIPY in water following 501 nm excitation caused a 3.6 fold enhancement of the acceptor BODIPY emission at 601 nm indicating efficient energy transfer between the green emitting donor BODIPY and the red emitting BODIPY acceptor with a 100 nm Stokes shift. The calculated FRET efficiency was 96.5%. Encapsulated BODIPY derivatives were highly stable under our experimental conditions.

Simple, accurate, and eco-friendly spectrophotometric procedures were proposed and implemented for simultaneous determination of anticoccidial drugs from three different classes namely, amprolium hydrochloride (AMP), sulfaquinoxaline sodium (SQX) and diaveridine hydrochloride (DVD). Dual wavelength in ratio spectra procedure was proposed where the difference in amplitudes (ΔP) in the ratio spectra at 264 nm and 301.9 nm (ΔP_{264&301.9 nm}) corresponded to AMP with mean percentage recovery 100.00±0.923%, while (ΔP_{250.9&279 nm}) and (ΔP_{218&243.5 nm}) corresponded to SQX and DVD with mean percentage recoveries 99.31±1.083 and 100.64±1.219%, respectively. The dual wavelength in ratio spectra procedure was validated according to the ICH guidelines and accuracy, precision and repeatability were found to be within the acceptable limit. Multivariate chemometric approaches, namely, partial least-squares (PLS-2) and principal component regression (PCR) were also proposed with mean percentage recoveries 99.31±0.769, 98.91±1.192 and 99.04±1.245% for AMP, SQX and DVD, respectively, in PLS-2 and 99.63±1.005, 99.11±1.272 and 98.93±1.338% for AMP, SQX and DVD, respectively, in PCR. These procedures were successfully applied to the multi-ingredient veterinary formulation with mean percentage recoveries 100.75±1.238, 99.29±0.875 and 99.34±0.745% for AMP, SQX and DVD, respectively, in dual wavelength in ratio spectra procedure and 101.03±1.261, 101.48±0.984 and 101.10±1.339% for AMP, SQX and DVD, respectively, in PLS-2 and 100.22±1.204, 101.10±0.546 and 100.91±0.677% for AMP, SQX and DVD, respectively, in PCR.

Soil organic matter (SOM) is usually quantified by Walkley-Black titration method or using a spectrophotometric method. This study proposes an alternative method for quantification of SOM using digital image from scanner and mathematical algorithms to replace titration and spectrophotometry procedures. For this, after SOM oxidation by potassium dichromate, digital images were acquired. Posteriorly, extraction of RGB color histograms from images have occurred, followed by the use of multivariate calibration method: partial least squares (PLS). Six soil samples were analyzed. We used the Walkley-Black method as reference. SOM was estimated by images using the PLS tool. The new method, besides being a fast, low cost, and more operational alternative, presented statistically equal results in relation to the reference method, as assessed by the Student t-test and F-test at 95 % confidence.

The title compound, 5-chlorospiro[indoline-3,7'-pyrano[3,2-c:5,6-c']dichromene]-2,6',8'-trione was synthesized via one-pot pseudo three-component reaction between one equivalent of 5-chloroisatin and two equivalents of 4-hydroxycoumarin using mandelic acid as catalyst in aqueous ethanol at 110 °C. The synthesized compound was characterized by FT-IR, ¹H NMR, and HRMS techniques. Single crystals were grown for crystal structure determination by using single X-ray crystallography technique. It was found that the crystals are triclinic with space group P-1 and Z = 1. The crystal structure was solved by direct method and refined by full-matrix least-squares procedures to a final R-value of 0.0688 for 6738 observed reflections. The crystal structure was stabilized by elaborate system of O-H···O, N-H···O, and C-H···O interactions with the formation of supramolecular structures. 3D Hirshfeld surfaces and allied 2D fingerprint plots were analyzed for molecular interactions. Molecular docking studies have been performed to get insights into the inhibition property of this molecule for Human topoisomerase IIα.

Ruthenium(II) complexes containing both 1,10-phenanthroline (Phen) and carbonyl (CO) ligands are important molecules for various applications including catalysis. In this work, the molecular structure of [Ru(Phen)₂(CO)₂]²⁺ was determined via X-ray diffraction analysis for the first time. The complex exhibits substitutional disorder of one of counter-anions in the asymmetric unit, with different occupancies for CF₃SO₃^- (0.72) and PF₆^- (0.28). The ruthenium atom is coordinated in a distorted octahedral environment by two carbonyl carbon atoms and four nitrogen atoms from bis-Phen ligands. The cation displays a cis configuration of the carbonyl ligands. Several hydrogen bonds and π-π interactions are present in the crystal. In addition to structural characterization, IR spectral data for the complex is compared with calculated values. These results provide fundamental data for understanding various properties of related ruthenium complexes.

The synthesis, characterization, and theoretical studies of a novel hydrazine, N,N’-bis-(3-quinolylmethylene)diphenylethanedione dihydrazone (1) has been reported. The molecular structure has been characterized by room-temperature single-crystal X-ray diffraction which reveals that two quinoline moieties are disposed nearly perpendicularly around the central C-C bond giving a ‘L’ shape of the molecule. This particular geometry gives rise to the hydrogen-bonded supramolecular rectangle of two self-complementary molecules. These supramolecular units are further assembled by π-π interaction. The Hirshfeld surface analysis of compound 1 shows that C···C, C···H, H···H, and N···H interactions of 13.1, 9.9, 52.3, and 7.4%, respectively, which exposed that the main intermolecular interactions were H···H intermolecular interactions. Crystal data for C₃₄H₂₄N₆: Triclinic, space group P-1 (no. 2), a = 10.885(3) Å, b = 11.134(3) Å, c = 12.870(3) Å, α = 90.122(6)°, β = 114.141(6)°, γ = 110.277(5)°, V = 1316.1(6) Å³, Z = 2, T = 100(2) K, μ(MoKα) = 0.080 mm^-1, Dcalc = 1.304 g/cm³, 7309 reflections measured (3.518° ≤ 2Θ ≤ 39.276°), 2318 unique (R_int = 0.0527, R_sigma = 0.0565) which were used in all calculations. The final R₁ was 0.0416 (I > 2σ(I)) and wR₂ was 0.1074 (all data).

In this study, the spectroscopic characterization, frontier molecular orbital analysis, and natural bond orbital analysis (NBO) analysis were executed to determine the movement of electrons within the molecule and the stability, and charge delocalization of the 4H-1,2,4-triazol-4-amine (4-AHT) through density functional theory (DFT) approach and B3LYP/6-311++G(d,p) level of theory. Surface plots of the hybrids’ Molecular Electrostatic Potential (MEP) revealed probable electrophilic and nucleophilic attacking sites. The discussed ligand were observed to be characterized by various spectral studies (FT-IR, UV-Vis). The calculated IR was found to be correlated with experimental values. The UV-Vis data of the molecule was used to analyze the visible absorption maximum (λ_max) using the time-dependent DFT method. Since the principle of drug-likeness is usually used in combinatorial chemistry to minimize depletion in pharmacological investigations and growth, drug-likeness and ADME properties were calculated in this research to establish 4-AHT molecule bioavailability. Furthermore, molecular docking studies were carried out. Molecular docking analysis was performed for the title ligand inside the active site of the Epidermal Growth Factor Receptor (EGFR). The title compound’s anti-tumor activity against the cancer cell, in which EGFR is strongly expressed, prompted us to conduct molecular docking into the ATP binding site of EGFR to predict whether this molecule has an analogous binding mode to the EGFR inhibitors (PDB: ID: 1M17).

Benzodiazepines are widely used to treat anxiety, insomnia, agitation, seizures, and muscle spasms. It works through the GABA_A receptors to promote sleep by inhibiting brainstem monoaminergic arousal pathways. It is safe and effective for short-term use, and arises some crucial side effects based on dose and physical condition. In this investigation, physicochemical properties, molecular docking, and ADMET properties have been studied. Density functional theory with B3LYP/6-311G+(d,p) level of theory was set for geometry optimization and elucidate their thermodynamic, orbital, dipole moment, and electrostatic potential properties. Molecular docking and interaction calculations have performed against human GABA_A receptor protein (PDB ID: 4COF) to search the binding affinity and effective interactions of drugs with the receptor protein. ADMET prediction has performed to investigate their absorption, metabolism, and toxic properties. Thermochemical data suggest the thermal stability; the docking result predicts effecting bindings and ADMET calculation disclose non-carcinogenic and relatively harmless phenomena for oral administration of all drugs.

The crystal structure investigation of the title compound 4-((pyrrolidin-1-ylsulfonyl) methyl)aniline (PSMA) C₁₁H₁₆N₂O₂S shows that the molecule is essentially coplanar with a dihedral angle of 26.70(14)°between the pyrrolidine and the benzene rings. A pair of strong N-H···O hydrogen bonds produces continuous two-dimensional sheets with R₂²(18) ring motifs. The crystal structure also features a weak C-H···π interaction resulting in a three-dimensional network. Density functional theory (DFT) calculations reveal that the experimental and calculated geometric parameters of the molecule are nearly the same. Hirshfeld surface analysis has been carried out to study the various intermolecular interactions responsible for the crystal packing. Theoretical calculations indicate an excellent correlation between the experimental and the simulated UV spectra.

The effect of HIV-1 on a human’s immune system cannot be ignored. This is the virus that reduces the power of the immune system to fight against any disease. Of course, many anti-HIV drugs are available, and many computational studies have been done to find out their mechanism of action, but the computational study regarding the chemistry behind the mechanism of action was not done yet. Therefore, the main objective of the study was to clarify the chemistry behind the mechanism of action of commercially available anti-HIV drugs. The drugs taken in the presented study were Entry Inhibitors (EIs) and Non-nucleoside reverse transcriptase inhibitors. First, literature data was evaluated computationally to ensure the reliability of the software used for the presented study. It was found that interaction-based experimental results and computationally evaluated results of the literature data were the same. After that, by following the same procedure, a docking study was done on the drugs taken in the current study. In addition, the residues involved in the interactions of EIs and NNRTIs with their receptors were studied to determine the chemistry that acts behind the action of both. It was found that EIs and NNRTIs work differently. It was also predicted that the derivatization of both drugs could make them more effective and active. Therefore, the presented study will be very helpful in the field of medicinal science.

N-(2-Chlorophenylcarbamothioyl)cyclohexanecarboxamide was characterized by a single crystal X-ray diffraction study. Crystal data for this compound, C₁₄H₁₇ClN₂OS; Monoclinic, space group P2₁/n with Z = 4, a = 5.2385(10) Å, b = 17.902(4) Å, c = 15.021(3) Å, β = 90.86(3)°, V = 1408.5(5) Å³, T = 153(2) K, μ(MoKα) = 0.413 mm^-1, Dcalc = 1.400 g/cm³, 9840 reflections measured (7.082° ≤ 2Θ ≤ 50.378°), 2519 unique (R_int = 0.0406, R_sigma = 0.0335) which were used in all calculations. The final R₁ was 0.0397 (I > 2σ(I)) and wR₂ was 0.0887 (all data). The puckering parameters (q₂ = 0.019(3) Å, q₃ = 0.578(3) Å, θ = 1.0(3)° and φ = 51(8)°) of the title compound show that the cyclohexane ring adopts a chair conformation. The molecular conformation of the title compound is stabilized by intramolecular hydrogen bonds (N2-H2⋅⋅⋅Cl1, N2-H2⋅⋅⋅O1, and C2-H2A⋅⋅⋅S1) and intermolecular hydrogen bonds (N1-H1⋅⋅⋅S1ⁱ and C9-HA⋅⋅⋅S1ⁱi: 2-x, 2-y, 1-z). The intramolecular hydrogen bonds (N2-H2⋅⋅⋅O1 and C2-H2A⋅⋅⋅S1) are also form two pseudo-six-membered rings. Density functional theory optimized structure in the gaseous phase at B3LYP/6-311G(d,p) level of theory has been compared with the experimentally defined molecular structure. The molecular orbitals HOMO and LUMO with the energy gap for the title compound are calculated and the estimated energy gap (ΔE) between the HOMO and LUMO energies levels of the title compound is 3.5399 eV, which implies that the title molecule is very reactive. The Hirshfeld surface analysis reveals that the most important contributions to crystal packing are from H···H (49.0%), H···C/C···H (12.5%), H···Cl/Cl···H (10.9%), and H···S/S···H (10.0%) interactions. The energy-framework calculations are used to analyze and visualize the three-dimensional topology of the crystal packing. The intermolecular energy analysis confirmed a significant contribution of dispersion to the stabilization of molecular packings in the title compound.

This study was aimed to assess the antibacterial and antifungal activities of Balanites aegyptiaca seed oil and characterize the physicochemical properties. Seeds were collected from the local central market, Khartoum-Sudan (2019). The samples were dried under shade and grinded, then the oil was extracted with a Soxhlet extractor using n-hexane. The percentage yield of the extract was found to be 25.64%. The seed oil was tested against Pseudomonas aeruginosa (G-), Escherichia coli (G-), Bacillus subtilis (G+), Staphylococcus aureus (G+), and Candida albicans to assess their antimicrobial properties. The extract of B. aegyptiaca seed oil has antimicrobial activity against most of the organisms tested. The fatty acid profile of the B. aegyptiaca seed oil was analyzed by GC/MS. The results revealed that the presence of five fatty acids, including saturated linoleic acid, oleic acid, and unsaturated palmate and stearic acids, also a unique antioxidant compound butylated hydroxytoluene. The physiochemical properties of the seed oil showed that the oil contained kinetic viscosity (57 cp), density (0.917 g/cm³), refractive index (1.472), acid value (49.96 mg/kg), saponification value (248.75 mg/g), ester number (234.79 mg/kg) and peroxide number (0.02 mg/kg). Through physiochemical analysis, it was found that oil can be used for human consumption due to the percentage yield of unsaturated acids (81%). In addition, the results of the antioxidant activity of the seeds oil showed that the seed oil had moderate antioxidant activity.

The Schiff base compound, N-((2-ethoxynaphthalen-1-yl)methylene)-4-fluoroaniline, has been synthesized and characterized by X-ray diffraction method. The title compound, C₁₉H₁₆FNO, crystallizes in triclinic, space group P-1 (no. 2), a = 10.6343(9) Å, b = 11.4720(10) Å, c = 13.8297(13) Å, α = 102.466(7)°, β = 104.763(7)°, γ = 98.972(7)°, V = 1552.7(2) Å³, Z = 4, T = 293(2) K, μ(MoKα) = 0.086 mm^-1, Dcalc = 1.255 g/cm³, 24355 reflections measured (3.16° ≤ 2Θ ≤ 51°), 5779 unique (R_int = 0.0794, R_sigma = 0.0696) which were used in all calculations. The final R₁ was 0.0373 (I > 2σ(I)) and wR₂ was 0.0763 (all data). The title compound contains two molecules with a similar structure in the asymmetric unit cell. The packing of the crystal structure is determined by weak C–H···F and C-H···N intermolecular hydrogen bonds. The contributions of these weak interactions in the crystal structure were calculated by the Hirshfeld surfaces and examined by the intermolecular interactions within the structure. The existence, nature and percentage contribution of different intermolecular interactions H···H, C···H, N···H, and F···H were determined using Hirshfeld surface analysis and fingerprint plots.

This study is composed of X-ray diffraction and Density Functional Theory (DFT) based molecular structural analyses of 2-phenyl-4-(prop-2-yn-1-yl)-2,4-dihydro-3H-1,2,4-triazol-3-one (2PPT). Crystal data for C₁₁H₉N₃O: Monoclinic, space group P2₁/c (no. 14), a = 7.8975(2) Å, b = 11.6546(4) Å, c = 11.0648(3) Å, β = 105.212(2)°, V = 982.74(5) Å³, Z = 4, T = 296.15 K, μ(MoKα) = 0.091 mm^-1, Dcalc = 1.346 g/cm³, 13460 reflections measured (5.174° ≤ 2Θ ≤ 64.72°), 3477 unique (R_int = 0.0314, R_sigma = 0.0298) which were used in all calculations. The final R₁ was 0.0470 (I > 2σ(I)) and wR₂ was 0.1368 (all data). The experimentally determined data was supported by theoretically optimized calculations processed with the help of Hartree-Fock (HF) technique and Density Functional Theory with the 6-311G(d,p) basis set in the ground state. Geometrical parameters (Bond lengths and angles) as well as spectroscopic (FT-IR, ¹H NMR, and ¹³C NMR) properties of 2PPT molecule has been optimized theoretically and compared with the experimentally obtained results. Hirshfeld surface analysis with 2D fingerprinting plots was used to figure out the possible and most significant intermolecular interactions. The electronic characterizations such as molecular electrostatic potential map (MEP) and Frontier molecular orbital (FMO) energies have been studied by DFT/B3LYP approach. The MEP imparted the detailed information regarding electronegative and electropositive regions across the molecule. The HOMO-LUMO energy gap as high as 5.3601 eV was found to be responsible for the high kinetic stability of the 2PPT.

A new spectrophotometric reagent, salicylaldehyde-orthoaminophenol (Sal-OAP) has been synthesized and characterized for the determination of selenium through novel reaction techniques. Also, a new highly selective, and sensitive spectrophotometric method for the nano-trace determination of selenium using salicylaldehyde-orthoaminophenol (Sal-OAP) has been developed. Sal-OAP undergoes reaction in a slightly acidic solution (0.0001-0.0002 M H₂S0₄) with selenium (IV) to give an orange-red chelate, which has an absorption maximum at 379 nm. The reaction is instantaneous and absorbance remains stable for over 24 h. The average molar absorption co-efficient and Sandell’s sensitivity were found to be 6.4×10⁵ L/mol.cm and 1.0 ng/cm² of, respectively. Linear calibration graphs were obtained for 0.001-40.000 mg/Lof Se having detection limit of 0.1 µg/L and RSD 0-2 %. The stoichiometric composition of the chelate is 1:2 (Se:Sal-OAP). A large excess of over 60 cations, anions and some common complexing agents, such as chloride, azide, tartrate, EDTA, SCN¯etc., do not interfere in the determination. The developed method was successfully used in the determination of selenium in several Certified Reference Materials (Alloys, steels, human urine, bovine liver, drinking water, tea, milk, soil, and sediments) as well as in some environmental waters (Potable and polluted), biological fluids (Human blood, urine, hair, and milk), soil samples, food samples (Vegetables, rice, and wheat) and pharmaceutical samples (Tablet and syrup) and solutions containing both selenium (IV) and selenium (VI) as well as complex synthetic mixtures. The results of the proposed method for assessing biological, food and vegetables and soil samples were comparable with ICP-OES and AAS were found to be in excellent agreement. The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L).

Plasmodium falciparum is one of the most common resistant Plasmodium species responsible for high rates of morbidity and mortality in malaria patients. Clinical guidelines for the management of Plasmodium falciparum include the use of a dose of primaquine phosphate resulting intolerable side effects. Therefore, the aim of this work was to formulate primaquine phosphate-loaded PLGA nanoparticles by using a nanoprecipitation method in order to increase its bioavailability to minimize drug intake. This leads to reduced toxicity and better therapeutic efficacy of the drug. The synthesized nanoparticles were characterized by using dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (XRD). TEM analysis revealed the presence of smooth spherical-shaped nanoparticles. The drug DLS analysis confirmed the presence of negatively charged nanoparticles with particle size in the range of 100-400 nm. The drug release study was performed to analyses different kinetic models like zero-order model, first-order model, Higuchi model, Hixson-Crowell model, and Korsmeyer-Peppas model.

Zebrafish (Danio rerio) is a vertebrate animal used in animal model research with complex brains and behaviors similar to humans and associate with low coast become a model attractive for the academic community to seek zebrafish for scientific research. Studies on diseases of the central nervous system (CNS) have advanced and news therapeutic agents were developed for treatment these disorders. Reports suggest that the zebrafish model supports the neurodegenerative studies due functional conservation between human genes implicated in neurodegenerative disorders. The discovery of therapeutic compounds for CNS using the zebrafish model allows to show a neuroprotective action or neurotoxicity that might alter the behavioral changes. Neurotoxicity tests might perform in zebrafish’s embryos into 96 multi-well plates, which reduces the amount of substances used and cost. The bioactive compounds able to penetrate the blood-brain barrier (BBB) have important role physicochemical properties that might be desirable pharmacological effects and zebrafish trials allow if the substances might penetrate BBB and to exert central activity. The assays zebrafish are used to analyze nanoparticles that are small molecules used to explore variety applications in human health. Gold nanoparticles (AuNPs) has important properties which are extremely interest for pharmaceutical area such as drug delivery, cellular imaging, diagnostics, and therapeutic agents. Gold nanoparticles enhances Parkinson symptoms and improved neuroinflammation. Some studies show zebrafish might use to evaluate gold nanoparticles for human health hazard and toxicity studies. There is enormous potential for zebrafish in preclinical assays due to predict pharmacological and toxicity effects. Specific guidelines focused on methodologies in the zebrafish are needed to ensure adequate reproducible trials.

Herein we report crystallographic comparison of some geometrical and structural features for a series of biologically relevant bis-indole derivatives. Selected bond distances and bond angles of interest in a series of bis-indole derivatives have been discussed in detail. The biological activity of the substances has been correlated with based the structure-activity relationships (SAR) base which provides the different possibility of activity (Pa) and possibility of inactivity (Pi). For a better understanding of the packing interactions existing among these derivatives, an overview of crystal structure analysis with emphasis on the intramolecular hydrogen bonding in some bis-indole derivatives is presented. The role of hydrogen bonding in the crystal structure assembly of bis-indole derivatives has been found to be predominant and this observation reveals significant impact of hydrogen bonding in high value of drug-likeness of these bio-molecules.