https://journalirjpac.com/index.php/IRJPAC <p style="text-align: justify;"><strong>International Research Journal of Pure and Applied Chemistry (ISSN: 2231-3443)</strong> aims to publish original research articles, review articles and short communications in all aspects of pure and applied chemistry including analytical chemistry, biochemistry, medicinal chemistry, molecular biology and genetics, inorganic chemistry, organometallic chemistry, materials chemistry, chemistry of solids, liquids, polymers and interfaces between different phases, neurochemistry, nuclear chemistry, modern transmutation, organic chemistry, physical chemistry, phytochemistry, polymer chemistry, supramolecular and macromolecular chemistry, chemical thermodynamics, chemical kinetics, electrochemistry, statistical mechanics, spectroscopy, astrochemistry and cosmochemistry, quantum chemistry and theoretical chemistry, sonochemistry, agrochemistry, atmospheric chemistry, chemical engineering, chemical biology, chemo-informatics, electrochemistry, femtochemistry, geochemistry, green chemistry, histochemistry, immunochemistry, marine chemistry, mechanochemistry, nanotechnology, natural product chemistry, oenology, petrochemistry, pharmacology, photochemistry, radiochemistry, synthetic chemistry, kinetics and mechanisms of chemical reactions, thermochemistry, chemistry in industry and interactions between chemistry and environment. </p> en-US [email protected] (International Research Journal of Pure and Applied Chemistry) [email protected] (International Research Journal of Pure and Applied Chemistry) Mon, 03 Aug 2026 10:16:30 +0000 OJS 3.3.0.21 http://blogs.law.harvard.edu/tech/rss 60 https://journalirjpac.com/index.php/IRJPAC/article/view/1021 <p>A new zinc(II) complex, ZnCl(SCN)(H₂L)₂, derived from the Schiff base ligand N′-[(E)-(2-hydroxy)methylidene]pyridine-4-carbohydrazide (H₂L), was synthesised and structurally characterised by single-crystal X-ray diffraction. The complex crystallises in the orthorhombic space group Ama2, with unit-cell parameters a = 26.0306(2) Å, b = 16.0094(1) Å, and c = 6.840(1) Å. The asymmetric unit comprises two neutral H₂L ligands coordinated to the Zn²⁺ ion through their pyridine nitrogen atoms, one thiocyanate anion (SCN⁻) coordinated through nitrogen, one chloride anion, and one lattice water molecule. The zinc centre adopts a distorted tetrahedral geometry, with Zn–N bond lengths of 1.979(4) and 2.052(3) Å, a Zn–Cl bond length of 2.1919(12) Å, and bond angles that depart markedly from the ideal tetrahedral value (103–125°). To complement the structural study, the redox behaviour of the related copper(II) complex [Cu(H₂L)Cl·H₂O]Cl (L-4) was investigated by cyclic voltammetry in acetonitrile containing 0.1 M TEATFB, using a Pt disk working electrode (r = 2 mm), a stainless-steel wire counter electrode, and an Ag/AgCl reference electrode. Over the potential range −1.0 to +1.0 V versus SCE and at scan rates of 10–50 mV s⁻¹, the voltammograms displayed a single quasi-reversible redox couple, characterised by a sharp cathodic peak at −0.75 V and a broader anodic peak at −0.45 V versus SCE. The observation of a single redox wave indicates a uniform Cu(II) coordination environment, consistent with the structural and spectroscopic data obtained for the complex.</p> Ousmane Sall, Moussa Faye, Alassane Saïdou Diallo, Abdoul Sall, Farba Bouyagui Tamboura, Ibrahima Elhadj Thiam, Moussa Dieng, Mohamed Gaye Copyright (c) 2026 Author(s). The licensee is the journal publisher. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. https://journalirjpac.com/index.php/IRJPAC/article/view/1021 Mon, 03 Aug 2026 00:00:00 +0000 https://journalirjpac.com/index.php/IRJPAC/article/view/1022 <p>Chitosan is a biopolymer obtained by deacetylating chitin and is commonly produced from crustacean shell waste. This study compared the extraction and characterisation of chitosan from crab (<em>Callinectes amnicola</em>) and periwinkle (<em>Tympanotonus fuscatus</em>) shells under identical chemical conditions. The shell powders were subjected to demineralisation with 1.25 M HCl, deproteinisation with 2.5% NaOH, and deacetylation with 25% NaOH. The products were assessed for percentage yield, degree of deacetylation (DDA) by potentiometric titration, solubility, and functional groups by Fourier-transform infrared spectroscopy. Crab shells produced a chitosan yield of 18.4% and a DDA of 80.3%. The corresponding FTIR spectrum showed characteristic amine and polysaccharide bands and no residual carbonate peaks, indicating effective demineralisation and deacetylation. In contrast, periwinkle shells produced a lower yield of 10.9%, while the resulting product had a DDA of &lt;10% and poor solubility. Its FTIR spectrum showed strong carbonate bands and an absence of characteristic amine bands, indicating incomplete demineralisation and deacetylation. The periwinkle-derived product was therefore predominantly chitin rather than chitosan under the applied conditions. These findings show that identical processing conditions do not yield equivalent products from crustacean and molluscan shell matrices. Source-specific optimisation, particularly more intensive demineralisation and deacetylation for periwinkle shells, is required to improve conversion to chitosan.</p> Chioma K. Anyiam, Jovita A. Daniel Copyright (c) 2026 Author(s). The licensee is the journal publisher. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. https://journalirjpac.com/index.php/IRJPAC/article/view/1022 Wed, 12 Aug 2026 00:00:00 +0000