Citation :

Datta A. Patil, Rajkumar U. Pokalwar, "Synthesis and Characterization of New Cu(II) Complexes of ((2-Chloroquinolin-3-yl)Methylene)-3 Methoxyaniline," International Journal of Chemical Engineering Research, vol. 13, no. 1, pp. 1-6, 2026. Crossref, https://doi.org/10.14445/IJCER-V13I1P101

Abstract

A simple and efficient synthetic process was developed for preparing copper(II) complexes derived from the Schiff base ligand ((2-chloroquinolin-3-yl)methylene)-3-methoxyaniline. The ligand was synthesized through the condensation of equimolar 2-chloroquinolin-3-carbaldehyde and 3-methoxyaniline in ethanol under mild conditions. The obtained product has high purity within one hour. Subsequent reaction with copper(II) chloride in ethanol produced air-stable coordination complexes exhibiting various metal-to-ligand stoichiometries. Formation and purity were rigorously confirmed by multiple spectroscopic techniques, ¹H NMR verified the characteristic –CH=N– imine linkage via proton shifts; IR spectroscopy displayed bands indicative of C=N bond stretching and metal-ligand coordination vibrations; HRMS confirmed molecular structures through observed mass fragmentations ions. These outcomes highlight the method’s simplicity, high efficiency, and reproducibility.

Keywords

2-Chloroquinoline-3-carbaldehyde, Copper complexes, ((2-chloroquinolin-3-yl)methylene)-3-methoxyaniline, 3-methyoxyaniline.

References

1. Otto Meth-Cohn, Bramha Narine, and Brian Tarnowski, “A Versatile New Synthesis of Quinolines and Related Fused Pyridines, Part 5. The Synthesis of 2-Chloroquinoline-3-Carbaldehydes,” Journal of the Chemical Society, Perkin Transactions 1, pp. 1520-1530, 1981.
   [CrossRef] [Google Scholar] [Publisher Link]
2. Kirandeep Kaur et al., “Quinolines and Structurally Related Heterocycles as Antimalarials,” European Journal of Medicinal Chemistry, vol. 45, no. 8, pp. 3245-3264, 2010.
   [CrossRef] [Google Scholar] [Publisher Link]
3. Rizk Elsayed Khidre, Bakr Fathy Abdel-Wahab, and Farid Abdel-Rehem Badria, “New Quinoline-based Compounds for Analgesic and Anti-inflammatory Evaluation,” Letters in Drug Design & Discovery, vol. 8, no. 7, pp. 640-648, 2011.
   [Google Scholar] [Publisher Link]
4. Wafaa M. Abdou, Rizk E. Khidre, and Azza A. Kamel, “Elaborating on Efficient Anti‐Proliferation Agents of Cancer Cells and Anti‐Inflammatory‐Based N‐Bisphosphonic Acids,” Archiv der Pharmazie, vol. 345, no. 2, pp. 123-136, 2012.
   [CrossRef] [Google Scholar] [Publisher Link]
5. Brahmam Medapi et al., “Design and Synthesis of Novel Quinoline–Aminopiperidine Hybrid Analogues as Mycobacterium Tuberculosis DNA GyraseB Inhibitors,” Bioorganic & Medicinal Chemistry, vol. 23, no. 9, pp. 2062-2078, 2015.
   [CrossRef] [Google Scholar] [Publisher Link]
6. N.C. Desai, G.M. Kotadiya, and A.R. Trivedi, “Studies on Molecular Properties Prediction, Antitubercular and Antimicrobial Activities of Novel Quinoline based Pyrimidine Motifs,” Bioorganic & Medicinal Chemistry Letters, vol. 24, no. 14, pp. 3126-3130, 2014.
   [CrossRef] [Google Scholar] [Publisher Link]
7. Rajkumar U. Pokalwar et al., “Synthesis and Antibacterial Activities of α-Hydroxyphosphonates and α-Acetyloxyphosphonates Derived from 2-Chloroquinoline-3-Carbaldehyde,” Arkivoc, pp. 196-204, 2006.
   [CrossRef] [Google Scholar] [Publisher Link]
8. Shreelekha Adsule et al., “Novel, Schiff base Copper Complexes of Quinoline-2-Carboxaldehyde as Proteasome Inhibitors in Human Prostate Cancer Cell,” Journal of Medicinal Chemistry, vol. 49, no. 24, pp. 7242-7246, 2006.
   [CrossRef] [Google Scholar] [Publisher Link]
9. Rangappa S. Keri, and Siddappa A. Patil, “Quinoline: A Promising Antitubercular Target,” Biomedicine & Pharmacotherapy, vol. 68, no. 8, pp. 1161-1175, 2014.
   [CrossRef] [Google Scholar] [Publisher Link]
10. Ambika Srivastava, Mrityunjay K. Singh, and R.M. Singh, “Pyrazolo-fused Quinoline Analogues: Synthesis of 1H-pyrazolo [3, 4-b] Quinolines and 3-Amino-1H-Pyrazolo [3, 4-b] Quinolines from 3-Formyl and 3-cyano-2-Chloroquinolines,” Indian Journal of Chemistry. Sect. B: Organic Chemistry, Including Medical Chemistry, vol. 45, no. 1, pp. 292-296, 2006. [Google Scholar]
11. P. Sah, S.P. Garg, and S.R. Nautiyal, “Some New Biologically Active Quinoline Analogues,” Indian Journal of Heterocyclic Chemistry, vol. 7, no. 3, pp. 201-204, 1998.
    [Google Scholar]
12. Nafees Ahmed et al., “Synthesis and Anti-HIV Activity of Alkylated Quinoline 2, 4-Diols,” Bioorganic & Medicinal Chemistry, vol. 18, no. 8, pp. 2872-2879, 2010.
    [CrossRef] [Google Scholar] [Publisher Link]
13. Heinz H. Pertz, H. Christian Milhahn, and Eckart Eich, “Cycloalkanecarboxylic Esters Derived from Lysergol, Dihydrolysergol-I, and Elymoclavine as Partial Agonists and Antagonists at Rat 5-HT2A Receptors:  Pharmacological Evidence that the Indolo[4,3-fg]quinoline System of the Ergolines Is Responsible for High 5-HT2A Receptor Affinity,” Journal of Medicinal Chemistry, vol. 42, no. 4, pp. 659-668, 1999.
    [CrossRef] [Google Scholar] [Publisher Link]
14. Vladimir V. Kouznetsov et al., “Target-Oriented Synthesis of Antiparasitic 2-Hetaryl Substituted Quinolines based on Imino Diels-Alder Reactions,” Letters in Drug Design & Discovery, vol. 4, no. 4, pp. 293-296, 2007.
    [CrossRef] [Google Scholar] [Publisher Link]
15. Kazuhiko Nakatani, Shinusuke Sando, and Isao Saito, “Improved Selectivity for the Binding of Naphthyridine Dimer to Guanine–Guanine Mismatch,” Bioorganic & Medicinal Chemistry, vol. 9, no. 9, pp. 2381-2385, 2001.
    [CrossRef] [Google Scholar] [Publisher Link]
16. Emon Barua et al., “Characterization of Mechanical and Micro-architectural Properties of Porous Hydroxyapatite Bone Scaffold using Green Microalgae as Binder,” Arabian Journal for Science and Engineering, vol. 44, pp. 7707-7722, 2019.
    [CrossRef] [Google Scholar] [Publisher Link]
17. Gajendra S. Thakur et al., “Traditional and Sustainable Methods for the Synthesis of Quinoline Derivatives as Anticancer Agents (2019–Present): A Comprehensive Review,” Anti-Cancer Agents in Medicinal Chemistry, 2026.
    [CrossRef] [Google Scholar] [Publisher Link]
18. Mahdiyeh Davoodi, Mahnaz Farahi, and Moeteza Shiri, “Ni-Schiff base Complex Supported on FSM-16 as a Novel Efficient Nanocatalyst to Synthesize Quinolone-3-Carbonitrile Derivatives,” Journal of Molecular Structure, 2026.
    [CrossRef] [Google Scholar] [Publisher Link]
19. Sandeep Yadav et al., “Synthesis, Properties, and Applications of Aminoquinoline-Derived Schiff Bases and Their Metal Complexes,” Russian Journal of Bioorganic Chemistry, vol. 52, 2026.
    [CrossRef] [Google Scholar] [Publisher Link]
20. A. Elmali, M. Kabak, and Y. Elerman, “The Rapid Synthesis of Schiff's bases without Solvent under Microwave Irradiation,” Journal Molecular Structure, 2000.  
    [Google Scholar]
21. P.R. Patel, B.T. Thaker, and S. Zele, “Preparation and Characterisation of Some Lanthanide Complexes Involving a Heterocyclic Beta-diketone,” Indian Journal of Chemistry. Section A: Inorganic, Bio-inorganic, Physical, Theoretical and Analytical Chemistry, vol. 38, no. 6, 1999.
    [Google Scholar] [Publisher Link]
22. Carol M. Metzler, Allen Cahill, and David E. Metzler, “Equilibriums and Absorption Spectra of Schiff Bases,” Journal of the American Chemical Society, vol. 102, no. 19, pp. 6075-6082, 1980.
    [CrossRef] [Google Scholar] [Publisher Link]
23. Gerald O. Dudek, and Emily Pitcher Dudek, “Spectroscopic Study of Keto–enol Tautomerization in Phenol Derivatives,” Chemical Communications (London), vol. 19, pp. 464-466, 1965.
    [CrossRef] [Google Scholar] [Publisher Link]
24. Nursen Sari et al., “Antibacterial Activites of Some New Amino Acid-Schi Bases,” Gazi University Journal of Science, vol. 16, no. 2, pp. 283-288, 2010.  
    [Google Scholar]
25. Manjusha Verma et al., “Anticonvulsant Activity of Schiff bases of Isatin Derivatives,” Acta Pharmaceutica, vol. 54, no. 1, pp. 49-56, 2004.
    [Google Scholar] [Publisher Link]
26. Sulekh Chandra, “EPR and Electronic Spectral Studies on Copper,” Journal of the Indian Chemical Society, vol. 81, no. 3, pp. 203-206, 2004.
    [Google Scholar]
27. Anish Mohindru, Joyce M. Fisher, and Marco Rabinovitz, “Bathocuproine Sulphonate: A Tissue Culture-compatible Indicator of Copper-mediated Toxicity,” Nature, vol. 303, pp. 64-65, 1983.
    [CrossRef] [Google Scholar] [Publisher Link]
28. S.N. Pandeya et al., “Synthesis and Screening for Anti-HIV Activity of Some N-Mannich Bases of Isatin Derivatives,” Chemotherapy, vol. 45, no. 3, pp. 192-196, 1999.
    [CrossRef] [Google Scholar] [Publisher Link]
29. Dr. Wolfgang Sawodny, and Manfred Riederer, “Addition Compounds with Polymeric Chromium (II)‐Schiff base Complexes,” Angewandte Chemie International Edition in English, vol. 16, no. 12, pp. 859-860, 1977.
    [CrossRef] [Google Scholar] [Publisher Link]
30. A. Bottcher et al., “Irreversible Enzymatic Inhibition by Cobalt Chelate Complexes,” Journal of Inorganic Biochemistry, vol. 59, noi. 2-3, pp. 221-221, 1995.
    [Google Scholar]
31. George J.P. Britovsek et al., “Imine Versus Amine Donors in Iron‐based Ethylene Polymerisation Catalysts,” European Journal of Inorganic Chemistry, vol. 2001, no. 2, pp. 431-437, 2001.
    [CrossRef] [Google Scholar] [Publisher Link]
32. Sulekh Chandra, and Rajiv Kumar, “Synthesis and Spectral Studies on Mononuclear complexes of Chromium(III) and Manganese(II) with 12-Membered Tetradentate N2O2, N2S2 and N4 Donor Macrocyclic Ligands,” Transition Metal Chemistry, vol. 29, pp. 269-275, 2004.
    [CrossRef] [Google Scholar]  [Publisher Link]
33. Raziyeh Arab Ahmadi, and Saeid Amani, “Synthesis, Spectroscopy, Thermal Analysis, Magnetic Properties and Biological Activity Studies of Cu(II) and Co(II) Complexes with Schiff Base Dye Ligands,” Molecules, vol. 17, no. 6, pp. 6434-3448, 2012.
    [CrossRef] [Google Scholar] [Publisher Link]
34. Mohammad Shakir et al., “Template Synthesis and Physicochemical Studies of 14-Membered Functionalized Pendant Arm Schiff-Base Macrocyclic Complexes of Co(II), Ni(II), Cu(II), and Zn(II): DNA Binding Studies on a Cu(II) Complex,” Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, vol. 41, no. 8, pp.1056-1062, 2011.
    [CrossRef] [Google Scholar] [Publisher Link]