Bulletin of the Chemical Society of Ethiopia

An enhanced spectrophotometric method for determination of hydrogen peroxide during vacuum ultraviolet photolysis of water

2024-12-31T10:27:50+00:00

This study re-evaluated the DPD/POD (N,N-diethyl-p-phenylenediamine/peroxidase from horseradish) spectrophotometric method for accurately detecting low-concentration hydrogen peroxide in water. It established that the absorption coefficient of the adduct product, DPD•+, at a wavelength of 320 nm was approximately two times higher than at 551 nm, indicating lower detection limits at 320 nm for H₂O₂ measurement. An optimal POD/DPD ratio of 1 was identified for effective H₂O₂ concentration determination. The effect of selected anions (chloride, sulfate, nitrate, and carbonate) on H₂O₂ determination was found to be negligible at concentrations below 1 g L^–1; however, at higher concentrations, these anions exhibited varying impacts on H₂O₂ measurement. The enhanced DPD/POD method is demonstrated as an effective tool for investigating the mechanism of vacuum ultraviolet (VUV) processes by accurately detecting low-concentration H₂O₂ formed in situ during the photolysis of water. The findings provide insights into the optimal conditions for H₂O₂ determination by this spectrophotometric method and highlight the minimal influence of inorganic anions under specific conditions. This study not only enhances the understanding of H₂O₂ measurement in VUV-induced reactions but also underscores the potential applications of the DPD/POD method in exploring the dynamics of VUV processes.

KEY WORDS: Spectrophotometric method, Hydrogen peroxide, Peroxidase from horseradish, Vacuum ultraviolet.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 397-408.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.1

Extraction and preconcentration of many metals ions by using CPE technique

2024-12-31T10:32:13+00:00

Cloud point extraction is a simple, safe, and environmentally friendly technique for preparing many different kinds of samples. In this review, we discussed the CPE method and how to apply it to our environmental sample data. We also spoke about the benefits, problems, and likely developments in CPE. This process received a great deal of attention during preconcentration and extraction. It was used as a disconnection and follow-up improvement system before the natural mixtures (nutrients, polybrominated biphenyl ethers, pesticides, polycyclic sweet-smelling hydrocarbons, polychlorinated compounds, and fragrant amines) and inorganic mixtures were examined and many metals like (silver, lead, cadmium, mercury, and so on). We also find that combining CPE with various methods can yield good results by increasing the sensitivity of analysis and eliminating the effect of interference from the sample background.

KEY WORDS: Cloud point extraction, Preconcentration of metal ions, Surfactant, Medications, Biological matrix.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 409-423.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.2

Micelle-mediated extraction combined with the adsorption onto magnetic nanoparticles for the extraction of crystal violet from wastewater

2024-12-31T10:35:01+00:00

This work describes cloud point extraction combined with the adsorption onto magnetic nanoparticles (MNPs) for separation and spectrophotometric determination of crystal violet (CV). Briefly, CV molecules were adsorbed on MNPs and transferred into the surfactant-rich phase of Triton X-114. Subsequently, the target analyte was desorbed from MNPs by acidified ethanol and detected spectrophotometrically. The impact of experimental conditions, including pH, electrolyte, amount of Triton X-114 and MNPs, incubation temperature and time, type, and volume of the eluent was investigated. The calibration curve was linear in the range of 1.5-250.0 µgL^-1 of CV. A preconcentration factor of 42.9 was obtained, and the detection limit for CV was 0.5 µgL^-1. The intra-day and inter-day relative standard deviations (RSD) for five replicate analyses of CV (100 µgL^-1) were 1.7% and 2.1, respectively. The developed approach was effectively used for quantitative analysis of CV in environmental water samples with accepted recovery (97.0-101.2%). The procedure is accurate, precise, rapid and low-cost.

KEY WORDS: Cloud point extraction, Solid phase extraction, Fe3O4 nanoparticles, Crystal violet, Wastewater samples.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 425-435.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.3

A Cu(II) coordination compound constructed by mixed ligands of 1,10-phenanthroline and carboxylic acid: Synthesis, characterization and Hirshfeld surface analysis

2024-12-31T10:37:20+00:00

Synthesis and full characterization of a new coordination compound, which was synthesized by mixed ligands under hydrothermal condition, namely [Cu(L)₂(phen)₂(H₂O)₂]·4H₂O (1) (phen = 1,10-phenanthroline, H₂L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium). Cu(II) is six-coordinated in a slightly twisted [CuN₂O₄] octahedral geometry. 1 displays 2D supramolecular layer, which is further extended into a 3D network by the π-π stacking and hydrogen bonds. 3D Hirshfeld surface analysis is combined with 2D fingerprint plots to investigate the contribution of different intermolecular interactions within the crystal. DFT calculations are also performed.

KEY WORDS: Cu(II), 1,10-phenanthroline, Coordination compound, Hirshfeld surface analysis, DFT calculation.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 437-446.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.4

Synthesis of novel complexes derived from methyl or benzyl 4-amino antipyrinyl dithiocarbamtes with divalent Mn(II), Co(II), Ni(II), Zn(II) and Cu(II)

2024-12-31T10:40:25+00:00

Two new ligands, methyl 4-amino antipyrinyl dithiocarbamates (MAC) and benzyl 4-amino antipyrinyl dithiocarbamates (BAC), were synthesized from 4-amino antipyrine and corresponding methyl or benzyl halides with potassium hydroxide in dimethylformamide. Then they were coordinated with five divalent transition metals: M = Mn, Co, Ni, Zn, and Cu(II) to produce ten novel complexes, [M(MAC)2]Cl₂ I(a-e) and [M(BAC)₂]Cl₂ II(a-e), which were characterized by some physical properties and spectral methods, elemental analyses, molar conductance, and magnetic susceptibility, in addition to ¹H NMR, FT-IR and UV-Vis. Spectroscopy proved that all metal complexes I(a-d) and II(a-d) have octahedral geometries, except those of copper complexes (Ie) and (IIe), which have square planer geometry (D4h). Following screening for biological activity against Gram-positive bacteria (Streptococcus pyogenes) and Gram-negative bacteria (Pseudomonas aeruginosa), the results of these novel complexes' investigations showed no effect except the complexes of [Zn(BAC)₂]Cl₂ II(a), [Zn(MAC)₂]Cl₂, I(a), [Mn(MAC)₂]Cl₂, I(b) and the ligand (MAC) are given promising data.

KEY WORDS: 4-Amino antipyrine, Dithiocarbamates, Dithiocarbamate complexes, Biological activity

Bull. Chem. Soc. Ethiop. 2025, 39(3), 447-457.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.5

Synthesis of and characterization some platinum(IV) complexes derived from substituted imides and evaluation of their biological activity

2024-12-31T10:43:38+00:00

This research paper explores preparation of furanoanthracene-12,14-dione (1) via the addition of malic anhydride to anthracene. The resultant compound was treated with urea to form the imide derivative (2). Subsequently (2) was reacted with formaldehyde, leading to the substitution of the nitrogen-bound proton with a hydroxymethyl group, yielding hydroxymethyl pyrroloanthracene (3). In the following step, various substituted anilines were reacted with (3) in the presence of triethylamine through an SN2 reaction to replace the hydroxyl group and producing substituted amino methyl-epipyrroloanthracene derivatives (4-10). Three of these derivatives (4-6) were employed as a ligands to synthesize three complexes square planer platinum(IV). The result of conductivity measurement, magnetic and C.H.N. prove the synthesis of the platinum(IV) complexes. The biological activities of the synthesized compounds were evaluated against four bacterial strains. Additionally, (4-10) were subjected to molecular docking studies against the target protein Penicillin Binding Protein (PDB ID: 3vsl), with Penicillin G serving as the control.

KEYWORDS: Platinum complexes, Imides, Molecular docking, Biological activity.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 459-472.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.6

Preparation and characterization of a mixed catalyst of cobalt and molybdenum carried on aluminum oxide prepared from bentonite ore

2024-12-31T10:46:10+00:00

The research aims to select one of the natural ores (bentonite clays) for preparing alumina (Al₂O₃) and using it as a support material for the catalyst. The components of the ore were studied using modern techniques such as energy dispersive X-ray (EDX) technique and X-ray fluorescence (XRF) technique. Then, alumina (aluminum oxide) was prepared from the bentonite ore after a series of chemical treatments were carried out on it in order to remove the components that negatively affect the effectiveness of the catalyst under study. After that, the catalyst consisting of transition elements (cobalt/molybdenum) supported on alumina was prepared and its chemical content was identified and the weight and atomic percentages were determined by measuring energy dispersive X-rays (EDX) and identifying its thermal stability by conducting thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The structure of the prepared catalyst was examined using BET technique and SEM (scanning electron microscope) measurement, in addition to X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurements to identify the percentages of the minerals composing the catalyst, and then estimate the percentage of these elements in their oxide form.

KEYWORDS: Catalyst, Bentonite, Cobalt, Molybdenum.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 473-482.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.7

Antibacterial and antioxidant activity of plant-mediated green synthesized silver nanoparticles using Cissus quadrangularis aqueous extract

2024-12-31T10:48:54+00:00

Plant-based green-synthesized silver nanoparticles (AgNPs) are valuable because of their advantages over traditional methods. This study examines the environment-friendly synthesized AgNPs using Cissus quadrangularis (CQ) stem aqueous extract. The optimum parameters for AgNP synthesis were a volume of plant extract (15 mL), aq. AgNO₃ concentration (0.10 mM), AgNO₃ volume (20 mL), reaction time (10 min), pH (11), and temperature (45 ^oC). The synthesized AgNPs at optimum conditions were characterized through UV-Visible spectroscopy, FTIR, XRD, and SEM. In colloidal solutions, the occurrence of CQ-AgNP was studied through the color change measured by the UV-visible spectrum, which confirms the developed AgNPs with a typical resonance spectrum (at 430 nm). The percentage yield of synthesized AgNPs was also estimated as 94.32%. The FTIR spectra exhibit the availability of CQ phytochemicals responsible for the reduction, capping, and stabilization of Ag⁺ of CQ-AgNP. The XRD pattern and SEM results show that the generation of highly crystalline spherical shapes of AgNPs has a mean diameter of 8.68 nm. Also, CQ-AgNPs had significant antibacterial activity against S. aureus and E. coli. The CQ-AgNPs had better antioxidant activity compared to the ascorbic acid standard. Thus, this study recommends that the presently studied CQ-AgNPs may be used as a remedial agent for biomedical applications.

KEY WORDS: Antibacterial, Antioxidant, Cissus quadrangularis, Green synthesis, Silver nanoparticles.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 483-502.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.8

Towards the comparison synthesis of Fe3O4 nanocatalysts using two different systems in Fischer–Tropsch process

2024-12-31T10:51:40+00:00

Two types of nanocatalyst were synthesized using two different catalytic systems Fe₃O₄/ paraffin/polymethyl methacrylate (Fe₃O₄/pr/PMMA) and Fe₃O₄/paraffin/urotropine (Fe₃O₄/Pr/Uro) in Fischer–Tropsch synthesis (FTS) and downloaded in the slurry-bed reactor (SBR), their effect in the FTS performance and liquid hydrocarbons productivity were studied. The thermal decomposition method was used to prepare the nanoiron oxide nanocatalysts using the two systems. The results show that the two different systems affect the sizes of particle and gave nanoparticles with various sizes. The Fe₃O₄/paraffin/polymethyl methacrylate system nanocatalysts show good adsorption of syngas (CO:H₂), with high activity as compared to Fe₃O₄/paraffin/urotropin in the FTS system. In addition, the polymethyl methacrylate polymer has enhanced the interaction between Fe₃O₄ NPs and CO:H₂ molecule, leading improved syngas chemical adsorption and the formation of liquid hydrocarbons at all experimental temperatures, but with urotropin the conversion of CO was reduced when heated over 260 °C, and leading to lower the liquid hydrocarbons formation.

KEY WORDS: Fischer–Tropsch synthesis, Iron oxide nanoparticles, Polymethyl methacrylate, Urotropin.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 503-514.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.9

Impact of graphene oxide integration with ZnO nanoparticles on its photocatalytic, antimicrobial, and antioxidant activities

2024-12-31T10:56:05+00:00

Zinc oxide nanoparticles (ZnO-NPs) are a type of nanomaterial that is biodegradable and has low toxicity and high compatibility with biological systems. They appear to have great potential for biomedical and photocatalysis applications, especially when compared to other metal oxide nanomaterials. Moreover, ZnO-NPs exhibit strong ultraviolet (UV) absorption properties, are cost-effective, and are easy to synthesize. However, pure ZnO-NPs have several limitations, including a wide energy bandgap, high excitation binding energy, poor photocatalytic activity in the visible range, and significant electron-hole recombination, which restrict their applications. To address these limitations, this study successfully incorporated graphene oxide (GO) into ZnO-NPs. Adding 4% GO reduced the energy band gap from 2.87 eV to 2.20 eV, significantly enhancing their activities. As a result of the integration, their photocatalytic activity enhanced, degrading 98% of methylene blue dye after 80 minutes of visible light exposure. Furthermore, GO incorporation boosted their antioxidant activity, increasing their half-maximal inhibitory concentrations (IC₅₀) from 38.38% to 51.60%. The nanocomposite exhibited superior antimicrobial activity compared to the pure ZnO-NPs and GO, indicating enhanced antimicrobial effects through GO integration. These enhancements are attributed to the improved band gap, stability, surface functionality, and nanocomposite morphology, as confirmed by various characterization methods.

KEY WORDS: Antimicrobial, Antioxidant, Dye degradation, GO/ZnO nanocomposite, Reactive oxygen species.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 515-534.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.10

Larvicidal and adulticidal effect of green synthesis copper oxide nanoparticles using Achillea fragrantissima and its biological and ultra-structural impact on Culex pipiens

2024-12-31T10:59:35+00:00

Chemical pesticides are often applied indiscriminately to control vectors, which led to development and unfavorable effects on beneficial organisms. Worldwide, phytochemicals and plant extracts have a multitude of medical uses and may be employed to remove a wide range of germs and pests. Environmentally friendly nanoparticle manufacturing and nanotechnology are the newest trends in a number of sectors. Utilizing a green method, Achillea fragrantissima extract (AcF) was employed to prepare copper oxide nanoparticles (CuONPs@AcF). Copper oxide nanoparticle was characterized using zeta potential, DLS and transmission electron microscope (TEM). During the study of the AcF extract effect against larvicidal and adulticidal, we found that the effect of AcF extract was less than CuONPs@AcF. Also, we studied the effect of AcF and CuONPs@AcF against the female mosquito's fertility. The effect of the tested substances on the female Culex pipiens ovary was improved by the ultrastructure.

KEY WORDS: Nanoparticles green synthesis, Copper oxide, Mosquito, Achillea fragrantissima extract.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 535-546.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.11

Exploration of the antioxidant and anticancer properties of methanolic extracts derived from five different Jasminum species, alongside an analysis of the phytoconstituent profile using GC-MS

2024-12-31T11:04:21+00:00

Several bioactive constituents found in conventional medicine possess antioxidant and anti-cancer effects and may be useful in the treatment of a variety of diseases, so the current study sought to conduct a thorough investigation of their potential use as a potent antioxidant and anticancer agent for five Jasminum species. The preliminary phytochemical analysis in a methanol extract of Jasminum indicated the existence of numerous bioactive secondary metabolites. More accurately, we discovered many novel compounds such deoxyspergualin, gentamicin B, cefazolin, cytidine, cycloheptanone oxime, folinic acid, 1-dodecene, epoxynonane derivative, dl-citrulline, thiocyanic acid, limonene 5,3',4'-trihydroxyflavone and 4-fluoro histidine. The results demonstrated that the plants have therapeutic values, since the extracts' antioxidant impact was examined using radical 2,2-diphenyl-1-picrylhydrazyl. The methanolic extract displayed varying half-maximal inhibitory concentration values slightly above the standard, indicating the significance of the bioactive metabolites present in the plant. Additionally, investigation was conducted on the potential anticancer properties targeting a specific liver cancer cell line and we revealed that J. azoricum was the powerful plant would effectively inhibit cancer cell lines at both 10 and 100 µg/mL.

KEY WORDS: Jasminum, Phytoconstituents, Anticancer, Antioxidant activity, GC-MS.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 547-560.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.12

Antioxidant constituents from the leaves of Piper crassipes Korth ex Miq. growing in Malaysia

2024-12-31T11:07:47+00:00

The genus Piper, belonging to the Piperaceae family, includes over 2,000 species, many of which are widely recognized for their significant economic and medicinal value. This study aimed to investigate the phytochemicals isolated from the leaf extract of Piper crassipes. Soxhlet extraction of the dried powdered leaves was employed to extract the phytochemicals using a polarity gradient of hexane, dichloromethane, and methanol. The phytochemicals were obtained using chromatography techniques and their structures were confirmed by spectroscopic analysis (IR, NMR, and MS) and comparison with the literature. Furthermore, the isolated phytochemicals were evaluated for their DPPH free radical scavenging activity. The isolation successfully led to the identification of ten phytochemicals: asaricin (1), chavibetol (2), dillapiole (3), β-sitosterol (4), 5,7-dimethoxyflavone (5), 4',5,7-trimethoxyflavone (6), N-(3-phenylpropanoyl)pyrrole (7), chavicol (8), N-isobutyl-(2E,4E,14Z)-eicosatrienamide (9), and 4-allyl resorcinol (10). Among the isolated phytochemicals, compounds (8) and (10) showed the highest DPPH radical scavenging activity, with IC₅₀ values of 189.3 and 195.8 µmol/L, respectively. This study offers important insights into the antioxidant potential of P. crassipes constituents, highlighting further opportunities to explore their nutraceutical and pharmaceutical applications.

KEY WORDS: Piperaceae, Piper crassipes, Constituent, Phenylpropanoid, Antioxidant.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 561-570.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.13

N-Doped activated carbon derived from water hyacinth for ultra-stable metal-free bifunctional electrode for zinc-air battery

2024-12-31T11:11:22+00:00

Activated N-doped carbon derived from water hyacinth leaves (WHL) was prepared and investigated as metal-free bi-functional catalyst for oxygen reduction and evolution (ORR/OER) in zinc-air batteries (ZABs). Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) methods were used to examine the morphology, elemental composition and the specific surface area of the samples, respectively. Linear sweep voltammetry (LSV) at rotating disk electrodes (RDEs) and rotating ring-disk electrodes (RRDEs) were employed to characterize the electrocatalytic activities. The electrochemical studies reveal that N-doped porous carbon from N-WHLs exhibited remarkable electrocatalytic activity for ORR, with an onset potential of 0.95 V and half-wave potential of 0.88 V comparable to commercial Pt/C catalyst. It also displays promising activity towards OER, with an overall potential of 1.86 V versus RHE to reach a current density of 10 mAcm^, resulting in an oxygen electrode activity (OEA) value of 0.98 V. The percentage of hydrogen peroxide produced was significantly low, with average electron transfer number value of 3.94 at 0.8 V for N-WHL. Furthermore, the ZAB using N-WHL catalysts as an air cathode displayed a power density of 84 mW cm⁻² and superior stability over 450 hours.

KEY WORDS: Bifunctional catalyst, Oxygen reduction reaction, Oxygen evolution reaction, Water hyacinth, Zinc-air battery.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 571-584.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.14

Computational details of molecular structure, spectroscopic properties, DFT calculations and molecular docking study of some 1,4-disubstituted-1,2,3-triazole derivatives derived from 4-aminobenzen sulfonic acid

2024-12-31T11:17:31+00:00

In the current study, structural optimization, electronic, vibrational properties and molecular docking simulation were investigated for two 1,4-disubstituted-1,2,3-triaozle derivatives (A and B). The theoretical spectroscopic analytical results of IR, NMR and UV–Vis were obtained using DFT methods, and the predicted results were compared to the experimental results reported in the literature. To forecast the highly electron-dense locations of the compounds, the molecular electrostatic surface potential, (MEP) was analyzed; and the quantum and chemical characteristics were computed. A thorough discussion of topological analysis using the reduced density gradient (RDG) was conducted. Moreover, to predict (in silico) the antiviral behavior of the reported heterocyclic compounds A and B, the crystal structures of the viral hepatitis C (6UE3 and 8DK6) were subjected to molecular docking simulation. The binding affinity between the heterocyclic ligands and the target proteins was investigated using molecular docking. The results showed that the triaozle derivatives have a good binding energy toward the virus target 8DK6 (-7.16 and -7.03 kcal/mol) for compound A and B, respectively. Herein, we introduce two triazole derivatives as potential anti-HCV.

KEYWORDS: 1,2,3-Triazole, Computational study, DFT, In silico, Molecular docking, HCV.

Bull. Chem. Soc. Ethiop. 2025, 39(3), 585-600.

DOI: https://dx.doi.org/10.4314/bcse.v39i3.15