International Journal of Chemistry

International Journal of Chemistry | Vol. 11, No. 7, July 2020 | pp. 49–56

DOI: 10.46882/2020/IJC/000141

Article Type: Original Research Paper

Title: Synthesis, Time-Resolved Photoluminescence, and Trace Explosive Sensing of Novel Samarium(III) Complex Networks

Names of Authors: A. O. Balogun¹, Y. K. Tanaka²*

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria.
²Department of Applied Chemistry, Tokyo Institute of Technology, Tokyo, Japan.

Abstract: Sm(III) coordination networks display specific orange-red luminescence tracks that serve as sensitive signaling systems for modern chemical detection platforms. This study details the chemical synthesis, structural characterization, and analytical sensing validation of a novel samarium(III) complex built with acetylacetone and 2,2'-bipyridine. The elemental compositions, crystal geometries, and binding architectures were resolved using elemental microanalysis, molar conductivity, and Fourier-transform infrared (FT-IR) spectroscopy. Quantitative data confirmed a 1:3:1 metal-to-ligand stoichiometry with an empirical formula of [Sm(acac)₃(bipy)]. Conductance profiles in acetonitrile established a non-electrolytic layout. Room-temperature photoluminescence scans showed narrow, characteristic emission peaks at 563 nm, 598 nm, and 642 nm, corresponding to the ⁴G₅/₂ to ⁶H_J (J = 5/2, 7/2, 9/2) transitions of the Sm(III) core. The operational utility of the complex as a fluorimetric sensor for trace nitroaromatic chemical explosives was tested systematically in aqueous systems. The introduction of 2,4-dinitrotoluene triggered an immediate, concentration-dependent quenching of the orange emission intensity. The fluorimetric quenching curve conformed tightly to the Stern-Volmer relationship, showing a high quenching constant (Ksv) of 3.4 x 10⁴ M⁻¹ and a low limit of detection (LOD) of 0.24 μM, driven by an intermolecular photoinduced electron transfer path.

Keywords: Samarium complexes; Rare earth elements; Photoluminescence; Fluorimetric sensor; Nitroaromatic explosives; Stern-Volmer equation

Manuscript Timeline: Received: January 14, 2020; Revised: March 02, 2020; Accepted: April 12, 2020; Published: July 04, 2020.

Citation: Balogun, A. O., & Tanaka, Y. K. (2020). Synthesis, Time-Resolved Photoluminescence, and Trace Explosive Sensing of Novel Samarium(III) Complex Networks. International Journal of Chemistry, 11(7), 49–56.

International Journal of Chemistry | Vol. 11, No. 2, February 2020 | pp. 9–16

DOI: 10.46882/2020/IJC/000136

Article Type: Original Research Paper

Title: Assessing the Hydrocarbon Tolerance and Phytoremediation Trait of Glycine max L. in Kerosene Spiked Soils

Names of Authors: O. F. Olawal¹, J. de Koning²*

Authors’ Affiliations:
¹Department of Plant Biology, University of Ilorin, Ilorin, Nigeria.
²Department of Environmental Sciences, Wageningen University, Wageningen, Netherlands.

Abstract: The accidental leakage of kerosene fuel from commercial storage tanks damages agricultural soil porosity and introduces toxic aromatic hydrocarbons into arable land, demanding green restoration strategies. This controlled study investigates the growth kinetics and remediation efficiency of Glycine max L. (Soybean) cultivated in soils artificially spiked with varying concentrations of industrial kerosene oil (1.0% to 4.0% w/w). Plant structural indices, remaining soil total petroleum hydrocarbon (TPH) concentrations, and root zone microbial populations were quantified over a 90-day developmental period. Glycine max demonstrated strong physiological tolerance, maintaining high root nodulation indices across all fuel loading levels below 3.0%. Gas Chromatography (GC-FID) profiling showed a 74.2% reduction in soil TPH content within the rhizosphere of cultivated systems, compared to minimal attenuation (22.5%) in unplanted controls. Soil microbiological testing revealed a five-fold expansion of heterotrophic degradation bacteria within the legume root matrix. This confirms that root exudates and symbiotic nitrogen-fixing bacteria actively interact to stimulate microbial proliferation, accelerating the degradation of complex petroleum structures in contaminated agricultural terrains.

Keywords: Kerosene fuel; Glycine max; Total petroleum hydrocarbons; Soil phytoremediation; Rhizosphere effect; Legume symbiosis

Manuscript Timeline: Received: June 08, 2019; Revised: July 20, 2019; Accepted: August 15, 2019; Published: February 09, 2020.

Citation: Olawal, O. F., & de Koning, J. (2020). Assessing the Hydrocarbon Tolerance and Phytoremediation Trait of Glycine max L. in Kerosene Spiked Soils. International Journal of Chemistry, 11(2), 9–16.

International Journal of Chemistry | Vol. 11, No. 4, April 2020 | pp. 25–32

DOI: 10.46882/2020/IJC/000138

Article Type: Original Research Paper

Title: Electrochemical Properties and Charge Storage Profiles of Polyaniline-Graphene Hydrogel Supercapacitor Electrodes

Names of Authors: U. B. Aliyu¹, K. Y. Lee²*

Authors’ Affiliations:
¹Department of Chemistry, Ahmadu Bello University, Zaria, Nigeria.
²Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore.

Abstract: Fabricating highly efficient electrochemical energy storage units requires the development of hybrid polymer electrodes that exhibit high specific capacitance and fast ion diffusion kinetics. This research details the synthesis and electrochemical characterization of polyaniline-graphene hydrogel (PANI-GH) self-assembling nanocomposites prepared via in situ chemical oxidative polymerization pathways. The surface topology and morphological features of the hybrid gels were analyzed using field emission scanning electron microscopy (FESEM), FT-IR, and Raman spectroscopy. FESEM imaging confirmed that a highly porous three-dimensional polyaniline layer was uniformly deposited across the conductive graphene skeletal network. Electrochemical performance was investigated via cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) loops in a 1.0 M H₂SO₄ electrolyte system. The optimized PANI-GH hybrid electrode delivered a maximum specific capacitance of 485 F/g at a current density of 1.0 A/g, which was substantially higher than standalone pure polyaniline films (215 F/g). Electrochemical impedance spectroscopy (EIS) data showed a very low charge-transfer resistance of 0.28 ohms, confirming accelerated ionic transport across the polymeric interface. Cyclic stability evaluations proved that the composite material retained 91.2% of its capacitive profile after 2000 continuous cycles.

Keywords: Polyaniline; Graphene hydrogel; Energy storage; Supercapacitors; Cyclic voltammetry; Specific capacitance

Manuscript Timeline: Received: July 22, 2019; Revised: August 25, 2019; Accepted: September 18, 2019; Published: April 02, 2020.

Citation: Aliyu, U. B., & Lee, K. Y. (2020). Electrochemical Properties and Charge Storage Profiles of Polyaniline-Graphene Hydrogel Supercapacitor Electrodes. International Journal of Chemistry, 11(4), 25–32.

International Journal of Chemistry | Vol. 11, No. 3, March 2020 | pp. 17–24

DOI: 10.46882/2020/IJC/000137

Article Type: Original Research Paper

Title: Mechanochemical Properties and Microstructural Performance of Fly Ash-Based Geopolymer Grout Reinforced with Nano-Titania Particles

Names of Authors: T. S. Ani¹, M. F. de Oliveira²*

Authors’ Affiliations:
¹Department of Electronic and Chemical Engineering, Enugu State University of Science and Technology, Enugu, Nigeria.
²Department of Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal.

Abstract: Developing high-performance geopolymer grouts from industrial wastes decreases production carbon footprints, though enhancing mechanical integrity requires structural optimization via reactive nanomaterial additives. This research tracks the structural development and mechanical profiles of geopolymer cements synthesized from fly ash integrated with nano-titania (nano-TiO₂) particles at dosages from 0% to 3.0% by weight. Alkaline activation was executed utilizing structural mixtures of sodium silicate and 12 M sodium hydroxide solutions. Hardening kinetics and microstructural phases were analyzed using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and Scanning Electron Microscopy (SEM). FT-IR spectra demonstrated the formation of a rigid aluminosilicate network, indicated by the prominent framework stretching bands shifting to 1012 cm⁻¹. Compressive strength experiments showed that grout cubes prepared with 2.0% nano-titania substitution reached a maximum compressive value of 58.4 MPa after 28 days of curing at room temperature, outperforming pure fly ash controls. SEM characterization revealed a highly dense matrix featuring intense structural crosslinking of aluminosilicate gel structures, which significantly reduces internal cracking.

Keywords: Geopolymer grout; Fly ash activation; Nano-titania; Compressive strength; Microstructure; Aluminosilicate networks

Manuscript Timeline: Received: July 14, 2019; Revised: August 18, 2019; Accepted: September 12, 2019; Published: March 05, 2020.

Citation: Ani, T. S., & de Oliveira, M. F. (2020). Mechanochemical Properties and Microstructural Performance of Fly Ash-Based Geopolymer Grout Reinforced with Nano-Titania Particles. International Journal of Chemistry, 11(3), 17–24.

International Journal of Chemistry | Vol. 10, No. 6, June 2019 | pp. 41–48

DOI: 10.46882/2019/IJC/000128

Article Type: Original Research Paper

Title: Development and Validation of a Spectrophotometric Method for Quantitative Determination of Ganciclovir in Pharmaceutical Formulations

Names of Authors: E. O. Effiong¹, J. M. S. Cardoso²*

Authors’ Affiliations:
¹Department of Chemistry, University of Uyo, Uyo, Nigeria.
²Department of Pharmacy, University of Coimbra, Coimbra, Portugal.

Abstract: Developing rapid, low-cost analytical protocols is essential for routine quality monitoring and the detection of substandard antiviral formulations in clinical testing laboratories. This paper describes the development and validation of a simple UV-Vis spectrophotometric method for the quantification of ganciclovir in pharmaceutical injections. The analytical procedure relied on the reaction of ganciclovir with 1,2-naphthoquinone-4-sulfonate in an alkaline medium, generating a highly stable orange-colored derivative monitored spectrophotometrically at its absorption maximum of 460 nm. Method validation parameters followed the International Council for Harmonisation (ICH) guidelines. Excellent linearity was established over a concentration range of 2.0 to 25.0 mg/L with a correlation coefficient (R²) of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were determined to be 0.08 mg/L and 0.24 mg/L, respectively. Precision assessments yielded relative standard deviations (RSD) below 1.8%. The validated method was successfully applied to screen commercial brands of ganciclovir formulations, producing recovery percentages between 98.6% and 101.4% with no interference from common excipients, making it suitable for routine quality control setups.

Keywords: UV-Vis spectrophotometry; Ganciclovir; Chemical derivation; Method validation; Pharmaceuticals; Quality control

Manuscript Timeline: Received: June 12, 2018; Revised: July 25, 2018; Accepted: August 18, 2018; Published: June 03, 2019.

Citation: Effiong, E. O., & Cardoso, J. M. S. (2019). Development and Validation of a Spectrophotometric Method for Quantitative Determination of Ganciclovir in Pharmaceutical Formulations. International Journal of Chemistry, 10(6), 41–48.

International Journal of Chemistry | Vol. 10, No. 7, July 2019 | pp. 49–56

DOI: 10.46882/2019/IJC/000129

Article Type: Original Research Paper

Title: Synthesis, Computational Docking, and Enzymatic Screening of Novel Indole-Linked Hydrazone Compounds

Names of Authors: O. M. Kolawole¹, E. R. Watson²*

Authors’ Affiliations:
¹Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria.
²Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.

Abstract: Inhibiting alpha-glucosidase represents a critical therapeutic target for managing postprandial hyperglycemia in type 2 diabetes mellitus. In this work, five novel indole-linked hydrazone derivatives were synthesized via the condensation of indole-3-carboxaldehyde with various substituted benzohydrazides in the presence of catalytic glacial acetic acid. The molecular frameworks of the synthesized targets were verified using elemental analysis, FT-IR, and ¹H-NMR spectroscopy. In vitro alpha-glucosidase enzyme inhibition assays revealed that compound 3c, bearing a p-nitro substituent, possessed the highest inhibitory potency, showing an IC50 value of 12.4 μM, compared to the acarbose clinical standard (IC50 = 38.2 μM). To investigate specific binding configurations, in silico molecular docking simulations were run inside the catalytic domain of alpha-glucosidase using AutoDock Vina software. The computational docking models demonstrated that the indole core forms stable hydrogen bonds with Asp214 and Arg315 residues. The aromatic ring extensions fit well into the hydrophobic pocket, engaging in significant pi-pi stacking interactions with Phe178. These structural contacts stabilize the ligand-protein topology, explaining the sub-micromolar inhibition constants and presenting a potential scaffold for further antidiabetic drug design.

Keywords: Indole; Hydrazones; Alpha-glucosidase; Enzyme inhibition; Molecular docking; Antidiabetic drug design

Manuscript Timeline: Received: July 20, 2018; Revised: August 28, 2018; Accepted: September 15, 2018; Published: July 08, 2019.

Citation: Kolawole, O. M., & Watson, E. R. (2019). Synthesis, Computational Docking, and Enzymatic Screening of Novel Indole-Linked Hydrazone Compounds. International Journal of Chemistry, 10(7), 49–56.