European Journal of Chemistry
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Metal(II) triazole complexes: Synthesis, biological evaluation, and analytical characterization using machine learning-based validation
Get PDFThe synthesis of many transition metal complexes containing 3,5-diamino-1,2,4-triazole (Hdatrz) as a ligand with different counter anions Br⎺, Cl⎺, ClO4⎺ and SO42- has been studied extensively, but the chemistry of transition metal nitrate and acetate compounds and their reactivity are relatively unexplored. In this research work, two new series of metal(II) complexes (M = Ni, Co, and Zn) {[Ni3(Hdatrz)6(H2O)6](NO3)6 (1), [Co3(Hdatrz)6(H2O)6](NO3)6 (2), [Zn3(Hdatrz)6(H2O)6](NO3)6 (3), [Ni3(Hdatrz)6(H2O)6](OAc)6 (4), [Co3(Hdatrz)6(H2O)6] (OAc)6 (5) and [Zn3(Hdatrz)6(H2O)6](OAc)6 (6)} have been synthesized. These synthesized complexes were characterized by various physicochemical techniques such as UV-vis spectroscopy, Fourier transform infrared spectroscopy, and magnetic susceptibility measurements. All six complexes were found to be trinuclear and bridged through the Hdatrz ligand. Spectral data suggested a distorted octahedral environment around the central metal ions in these complexes. It also revealed that the NH and OH groups are involved in hydrogen bonding. These complexes were tested against the fungal strains Colletotrichum gloeosporioides and Aspergillus niger. These synthesized complexes have not been observed to have antifungal activities. The machine learning K-nearest neighbours evaluates the analytical characteristics and solubility behavior of the metal complexes. Machine learning models provide results with 75% precision
Synthesis of coumarin-3-carboxylic acids in waste curd water: A green approach
Get PDFAn efficient and green protocol has been developed for the synthesis of derivatives of coumarin-3-carboxylic acid using waste curd water as a catalytic solvent. Curd water successfully catalyzes the reaction of 2-hydroxybenzaldehydes with dimethyl malonate under ultrasonic irradiation (40 °C) to construct different scaffolds of coumarin-3-carboxylic acid, with good to outstanding yields. The use of biodegradable solvents, sustainability, low reaction duration, mild reaction conditions without metals and Lewis acids, excellent yields, and compatibility with a wide range of electronically diverse substrates are all advantages of this synthesis process. Acidic curd water, which acts as a biological catalyst as well as a solvent for the reaction under ultrasonic irradiation, may be a better green alternative to some standard methods for synthesizing coumarin-3-carboxylic acids
Evaluation of Coulomb integrals with various energy operators to estimate the correlation energy in electronic structure calculations for molecules
Get PDFUsing energy operators RC1-nRD1-m, RC1-nr12-m, and r12-nr13-m with small (n, m) values is fundamental in electronic structure calculations. Analytical integrations of the cases (n, m) = (1, 0) and (0, 1) are based on the Laplace transformation with the integrand exp(-a2t2), the other cases are based on the Laplace transformation with the integrand exp(-a2t) and the two-dimensional version of the Boys function. These analytic expressions, with Gaussian function integrands, are useful for manipulation with higher moments of interelectronic distances, for example, in correlation calculations. The equations derived help to evaluate the one-, two-, and three-electron Coulomb integrals, òρ(1)RC1-nRD1-mdr1, òρ(1)ρ(2)RC1-nr12-mdr1dr2, and òρ(1)ρ(2)ρ(3)r12-nr13-mdr1dr2dr3, wherein ρ(i) is the one-electron density describing the electron clouds in molecules, solids, or any media or ensemble of materials. Analytical solutions to integrals are more useful than numeric solutions; however, the former is not available in many cases. We evaluate these integrals numerically, even more so, the òf(ρ(1))dr1 to òf(ρ(1),ρ(2),ρ(3))dr1dr2dr3 with the analytical function f. For this task, the commonly used density functional theory numerical integration scheme has been elaborated to 6 and 9 dimensions via Descartes product. More importantly, this numerical integration scheme works not only for Gaussian type but also for Slaterian types. Analogy is commented on in terms of the powerful empirical correction between quantum potential energy correction and the empirically corrected Newton’s universal law of gravity in the explanation of dark matter and energy, as well as its relation to Hartree-Fock and Kohn-Sham formalisms
QSAR study of benzofuran and indole derivatives to predict new compounds as histone lysine methyl transferase inhibitors
Get PDFInitiation and progression of several diseases by post-translational histone modifications are considered a worldwide problem. Enhancer of Zeste Homologue 2 (EZH2), which belongs to the histone-lysine N-methyl transferase (HKMT) family, has been emphasised as a promising target for cancer therapy. It is a major challenge for the scientific community to find novel approaches to treating this disease. In this study, a series of 51 derivatives of the benzofuran and indole families, previously experimentally evaluated against HKMT, was used to develop the best model with promising anticancer activity. The multiple linear regression (MLR) method, implemented in QSARINS software, was used with a genetic algorithm for variable selection. According to QSARINS, the model with two descriptors (minHBint4 and Wlambdal.unity) was found to be the best and its parameters fit well, and its validation was well established. The applicability domain was also validated for this model. Furthermore, its robustness (R2 = 0.9328), stability (Q2LOO = 0.9212, Q2LMO = 0.9187), and good predictive power (R2ext = 0.929) were also verified. Hence, this model was assumed to have predictive HKMT anticancer activity for designing active compounds. Molecular docking was also performed to identify binding interactions, and new molecules with better predicted biological activity (pIC50) were designed. The binding energy of the three designed compounds demonstrated higher binding activity at the target receptor, followed by complex stability, determined by a 100 ns molecular dynamics simulation and binding free energy calculation. Density functional theory (DFT) and pharmacokinetic analyses also confirmed their drug-like properties. Finally, it can be declared that the proposed tools allow rapid and economical identification of potential anti-HKMT drugs (anticancer drugs) for further development
Comparison of the performance of an organic acid and an inorganic acid pretreatment by means of enzymatic hydrolysis of coffee husk
Get PDFThe study of different lignocellulosic materials for second-generation biofuels is one of the trending topics today because of the high demand for fuels for transportation and electricity generation. Coffee husk is presented as one study option considering that only 10% of the coffee fruit is used for coffee production. The pretreatment of the coffee husk with sulfuric acid (3 or 6%) and citric acid (6 or 12%) was compared using two methodologies. The first had reaction condition time (50, 70, 90, and 1440 min) and temperature (70 and 90 °C), while the second had autoclave conditions (121 °C, 14.696 psi, 60 min). The comparison was made to find the best methodology for acid pretreatment before enzymatic hydrolysis. The best result of the reduction of sugars (17.017%) and glucose yield (3.882%) was found with 6% C6H8O7 in autoclaving (121 °C, 14.696 psi, 60 min) with hydrolysis conditions of 72 h, 150 rpm, 50 °C, and using cellulases from Trichoderma reesei
Magnetically recoverable nanocatalyst for the synthesis of pyranopyrazoles: CoFe2O4@SiO2-HClO4
Get PDFThe multiheterocyclic ring system shows valuable pharmaceutical and biological activities. In the present study, a microwave-assisted three-component reaction between aryl aldehyde, malononitrile, and 5-methyl-2,4-dihydro-3H-pyrazole-3-one led to the synthesis of pyrano[2,3-c]pyrazoles has been described. The reaction was carried out under solvent-free conditions in the presence of a new magnetically recoverable nanocatalyst (CoFe2O4@SiO2-HClO4). The reported protocol offers several advantages such as being environmentally benign, being rapid, inexpensive, having high atom and step economy, and being facile. The simple method of catalyst preparation, easy magnetic recovery, and reusability of the catalyst for four runs are notable features of the nanocatalyst. Antibacterial activity of all synthesized compounds was tested against Escherichia coli and Staphylococcus aureus. All synthesized compounds showed promising biological activity and may be used as a potential antibacterial candidate in biological science
Computational insights into the corrosion inhibition potential of some pyridine derivatives: A DFT approach
Get PDFIn the present investigation, the corrosion inhibition potency of five pyridine derivatives was computationally simulated and investigated by utilizing the Density Functional Theory (DFT) technique using a basis set of B3LYP/6-31++G (d,p). The predicted corrosion inhibition capacity was shown to improve in the order of 6-(trifluoromethyl) nicotinic acid > 4-(trifluoromethyl) nicotinic acid > N-methyl-4-chloropyridine-2-carboxamide > 2-chloro-6-trifluoromethylnicotinic acid > methyl 2-aminopyridine-4-carboxylate. Anticorrosion potentials were predicted using quantum chemical variables such as energy gap (∆E) i.e. HOMO-LUMO, ionization potential (I), electron affinity (A), proportion of electrons transmitted (∆N), hardness (η), softness (σ) and electronegativity (χ) of chemical species. It was often observed that the corrosion inhibiting rate improved with enhancement of EHOMO, σ, and reduced ELUMO, ∆E and η. Additionally, the electrostatic potential (ESP) mapping revealed that the heteroatoms, including the oxygen and nitrogen atoms, were the regions of anticipated electrophilic attack. This meant that atoms of oxygen and nitrogen could form bonds between the metallic substrate atoms and the investigated inhibitors. With the findings obtained, 4-methyl-2-aminopyridine-4-carboxylate showed the highest EHOMO (-0.23167 eV), softness (12.40694 eV-1) and the lowest ELUMO (-0.7047 eV), energy gap (0.1612 eV) and hardness (0.15107 eV), therefore revealed the excellent corrosion inhibiting attribution for several crucial metals and alloys, including aluminum, mild steel, stainless steel, zinc, brass, copper, etc
Organic contaminants in the groundwater of the Kerio Valley water basin, Baringo County, Kenya
Get PDFCurrently, groundwater is largely becoming the main source of fresh water in most developing countries. However, various deleterious impacts resulting from anthropogenic activities beneath the earth’s surface have significantly affected groundwater quality, as evidenced in several areas endowed with mineral and hydrocarbon deposits, agricultural activities, and industrial processes. The possible etiological impacts may include cancer and genetic aberrations which result from the toxic effects of organic waterborne contaminants ingested by humans and animals over time. The motivation behind this study was to identify and determine the concentration profiles of various organic pollutants in the wells located along the Kerio Valley water basin near the exploratory wells for hydrocarbons and mining activities. Therefore, this study is necessary in unraveling the level of organic contaminants in the sampled borehole water, which can then be extrapolated to cover other boreholes within the Kerio Valley basin. The study was carried out during the dry season of December 2022. The water samples from the boreholes were extracted using a solid phase extraction procedure and characterized using a gas chromatograph interfaced with a mass selective detector. The findings indicate that benzene derivatives which were mainly xylenes, 1,3,5-trimethylbenzene, 1-ethyl-3-methylbenzene, 1-methyl-2-propylpentylbenzene and polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene, fluoranthene, azulene, and pyrene were found in most of the boreholes sampled. Furthermore, long-chain hydrocarbons were present in all groundwater samples with varying concentrations. The concentration of benzene derivatives ranged from 2.84 to 20.47 ppm. However, polycyclic hydrocarbons exhibited the highest concentrations of all organic pollutants, with pyrene giving a concentration of 23.14 ppm, fluoranthene (18.54 ppm), phenanthrene (14.13 ppm) and anthracene (11.06 ppm). According to the findings reported in this study, most of the borehole water in the Kerio Valley basin is contaminated and may be unsafe for drinking. Most of the reported concentration levels were several times higher than the standards of the U.S. Environmental and Protection Agency. However, it is necessary to develop a policy framework on the assessment and monitoring of water quality in the region and propose urgent measures to ensure a clean water supply for the benefit of residents
Composition, antioxidant and anti-inflammatory activities of different polarity extracts of Artemisia nilagirica collected from hilly areas in the Himalayan terrain of Uttarakhand
Get PDFThe plant Artemesia nilagirica, collected from the terrain of the Himalayan region in Uttarakhand, India, was evaluated for its phytochemical composition, antioxidant and anti-inflammatory activities in vitro. The different polarity extracts of the plant were prepared and subjected to GC-MS analysis for their phytochemical composition. Twenty-six compounds were identified in the hexane extract of Artemisia nilagirica that represents 73.30% of the total area. The main compounds were tetracontane (15.21%), heneicosane (6.52%), and phytyl tetradecanoate (5.11%). The methanol extract yielded 26 compounds, accounting for 83.78% of the total compounds detected. The main compounds were palmitic acid (13.25%), alpha-linolenic acid (10.32%), oleamide (9.41%), phytol (8.58%), muco-inositol (7.27%), and neophytadiene (5.05%). The hexane and methanol extracts showed significant metal chelating activity having IC50 values of 2.23±0.01 and 2.41±0.02 µg/mL, respectively, with standard EDTA having an IC50 value of 2.22±0.01 µg/mL. The methanol extract showed a better anti-inflammatory property having an IC50 value of 2.97±0.03 µg/mL compared to the standard diclofenac potassium having an IC50 value of 3.79±0.01 µg/mL. The hexane extract showed better antioxidant activity in terms of metal chelating activity and reducing power activity than the methanol extract. The anti-inflammatory activity of both hexane and methanol extracts showed better results than the standard marketed drug diclofenac potassium. The current study reveals that Artemisia nilagirica plant extracts have potent antioxidant and anti-inflammatory activities. The effective biological compounds of plant extracts, such as phenols and flavonoids, can be potential alternatives to standard pharmaceuticals
Heavy metal concentrations in drinking water in the region north-east of Jhunjhunu, Rajasthan, India
Get PDFGroundwater is contaminated by undesirable elements that are introduced directly or indirectly into a natural water reservoir supplied by human activity, thus changing its physico-chemical properties. The north-east of Jhunjhunu in Rajasthan state of India was chosen as the study area due to the lack of research evidence in the past. The heavy metal content of a total of 42 water samples was analysed using an atomic absorption spectrometer. The copper and iron content in the groundwater of the study area is revealing a spatial distribution range of 1.75 to 4.01 mg/L for copper and 0.44 to 1.22 mg/L for iron. The obtained result was compared with Buero of Indian Standard (10500:2012), Indian Council of Medical Research, and World Health Organisation. There are iron and copper mining facilities in the studied area. Therefore, the concentration of both minerals was observed in the groundwater of all sampling stations. The iron and copper content are much higher in groundwater than the permissible limit of Buero of Indian Standard and World Health Organisation. The manganese content was not detected at all sampling sites. Both iron and copper elements are trace elements, and their higher concentration has proven to be a major problem and there are many health risks associated with it. These observed concentrations indicate a hazardous risk to human health. The official authorities should take the necessary measures in this regard