Synthesis, crystal structure and sulphide ion sensing study of a Cu(II) complex of aroyl hydrazone

• Published in: Polyhedron 2025-01, Vol.265, p.117294, Article 117294
• Main Authors: Chakraborty, Moumita, Mondal, Antu, Ghosh, Anwesha, Mahapatra, Alakananda, Mondal, Tapan Kumar, Chattopadhyay, Shyamal Kumar
• Format: Article
• Language: English
• Subjects: Benzoyl hydrazone; Crystal structure; Cu(II) complexes; Pyridoxal; Sulphide sensing
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2024.117294

A novel Cu(II) complex of formula [CuII(HL)(H2O)2]Cl (H3L = (4-((2-benzoylhydrazineylidene)methyl)-3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-1-ium chloride) is described. The complex is found to be capable of detecting S2− with a L.O.D. of 6.9 × 10−7 M. [Display omitted] Herein, we report a Cu(II) complex {[CuII(HL)(H2O)2]Cl} of a benzoylhydrazone Schiff base ligand (4-((2-benzoylhydrazineylidene)methyl)-3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-1-ium chloride) (H2L). The molar conductance in solution, magnetic susceptibility, ESI-MS and EPR spectroscopy have been performed to justify the structure of the complex. The solid-state structure of the complex has also been solved by single crystal X-ray diffractometry. Cu(II) centre is penta-coordinated with imine-N, phenoxide-O and deprotonated amide-O donor of the ligand and two H2O molecules occupying the coordination sphere forming a distorted square pyramidal geometry (τ = 0.32). We have studied the anion sensing property of the complex by monitoring the changes in the UV–Vis and fluorescence spectra of the complex in aqueous Tris-HCl buffer medium with incremental addition of various anions as tetrabutylammonium/sodium salts. The complex shows appreciable sensitivity toward sulphide ion, among various other anions, with association constant (Kb) for binding of the complex with S2− and lowest detection limit (L.O.D) value of 6.87 × 104 M−1 and 6.9 × 10−7 M, respectively. Thus, the complex can be used as an efficient S2− probe. The mechanism of sensing is found to be displacement of the fluorescent ligand from the Cu(II) complex by the sulphide ion.