Rajeshwar Rai, Anup Kumar Mishra | International Journal of Analytical and Applied Chemistry | Vol 12, Issue 02 | pp. 1-7 | ISSN: 2582-5933
Abstract
Abstract
An N, O-chelating azomethine Schiff base ligand (HL), chemically identified as 2-{[(thiophen-2-yl) methylidene] amino} benzoic acid, was synthesized by an equimolar condensation reaction between thiophene-2-carbaldehyde and anthranilic acid in absolute ethanol in the presence of a catalytic amount of acetic acid. The corresponding cobalt (II) complex, formulated as [Co(L)₂] · 2H₂O, was prepared by refluxing two equivalents of the ligand with one equivalent of cobalt (II) acetate tetrahydrate in ethanol, producing a deep brown crystalline solid in good yield. The synthesized ligand and its cobalt complex were comprehensively characterized using CHN elemental analysis, molar conductivity measurements in DMF, magnetic susceptibility determination, FT-IR spectroscopy, UV–Visible spectroscopy, 1H NMR spectroscopy, and FAB-mass spectrometry. The combined analytical and spectroscopic results confirmed a 1:2 metal-to-ligand stoichiometric ratio, in which the Schiff base acts as a monoanionic bidentate ligand by coordinating through the azomethine nitrogen atom and the deprotonated carboxylate oxygen atom. The cobalt (II) complex exhibited a magnetic moment of 4.80 B.M., indicating the presence of a high-spin Co (II) ion. Furthermore, the observation of three characteristic d–d transition bands in the electronic spectrum supported a six-coordinate, slightly distorted octahedral geometry around the cobalt center, with two coordinated water molecules occupying the trans-axial positions. The antimicrobial potential of both the free ligand and its cobalt complex was evaluated by the Agar-Well diffusion method against the bacterial strains Escherichia coli and Staphylococcus aureus and the fungal strains Aspergillus niger and Candida albicans. The cobalt (II) complex exhibited significantly greater antibacterial and antifungal activities than the free ligand, which may be attributed to enhanced lipophilicity and improved membrane permeability resulting from metal chelation, consistent with Tweedy’s chelation theory.
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- Cozzi PG. Chem Soc Rev. 2004;33:410.
- Vigato PA, Tamburini S. Coord Chem Rev. 2004;248:1717.
- Singh VP, Singh S, Katiyar A. J Enzyme Inhib Med Chem. 2009;24:1078.
- Mahmoud WH, Deghadi RG, Mohamed GG. J Therm Anal Calorim. 2016;124:1071.
- Jain S, Rana M, Sultana R, Mehandi R, Rahisuddin. Polycycl Aromat Compd. 2022;42:4768.
- Elaaraj I, Raouan SER, Nakkabi A, Es-sounni B, Koraichi I, El Moualij N, et al. J Indian Chem Soc. 2022;99:100574.
- Panchal PK, Pansuriya PB, Patel MN. Toxicol Environ Chem. 2006;88:57.
- El-Asmy AA, Babaqi AS, Al-Hubaishi AA. Transition Met Chem. 1987;12:521.
- Murukan B, Mohanan K. J Coord Chem. 2007;60:1565.
- Tweedy BG. Phytopathology. 1964;55:910.
- Khan TA, Tabassum S, Azim Y, Shakir M. Synth React Inorg Met-Org Chem. 2004;34:1135.
- Bi C, Fan Y. Synth React Inorg Met-Org Chem. 2004;34:935.
- Gupta LK, Bansal U, Chandra S. Spectrochim Acta A Mol Biomol Spectrosc. 2006;65:463.
- Rana VB, Singh P, Singh DP, Teotia MP. J Inorg Nucl Chem. 1980;42:459.
- Nakamoto K. Infrared and Raman spectra of inorganic and coordination compounds. Part B. 6th ed. New York: John Wiley & Sons; 2009.
- Lever ABP. Inorganic electronic spectroscopy. 2nd ed. Amsterdam: Elsevier; 1984.
- El-Dissouky A. J Coord Chem. 2004;57:671.
- Narang KK, Singh MK, Goyle MR, Bhuvaneshwari K, Singh V. Synth React Inorg Met-Org Chem. 1996;26:33.
- Cotton FA, Wilkinson G, Murillo CA, Bochmann M. Advanced inorganic chemistry. 6th ed. New York: Wiley-Interscience; 1999.
- Geary WJ. Coord Chem Rev. 1971;7:81.
- Hashem HE, Nath A, Kumer A. J Mol Struct. 2022;1250:131915.
- Lee J, Melchakova I, Nayab S, Kim K, Ko YH, Yoon M, et al. ACS Omega. 2023;8:6016.
- Khan SW, Khan W, Shah MIA. ACS Omega. 2023;8:17620.
- Çelik F, Inan Bektaş K, Güler Hİ, Direkel Ş, Ünver Y. Russ J Gen Chem. 2023;93:409.
- Mohamed AA, El-Gedamy MS, Sadeek SA, Elshafie HS. Chem Biodivers. 2025;22:e202501117.
How to cite this article
@article{RaiR2026,
author = {Rajeshwar Rai and Anup Kumar Mishra},
title = {Synthesis, Structural Elucidation, and Antimicrobial Screening of a Cobalt (II) Coordination Compound Derived from a Thiophene-Containing Schiff Base},
journal = {International Journal of Analytical and Applied Chemistry},
year = {2026},
volume = {12},
number = {02},
pages = {1--7},
issn = {2582-5933},
url = {https://journalspub.com/publication/ijaac/article=26710}
}