Synthesis, Characterization and Antimicrobial Studies of Copper Salophen Complex

• Dr.R.Jeevi Esther Rathnakumari

  english

  Author

The continuous emergence of antimicrobial-resistant pathogens has intensified the search for novel metal-based therapeutic compounds with improved biological activity and pharmacological efficiency. In this study, a Schiff base Salophen ligand and its Copper(II) salophen complex were synthesized, structurally characterized, and evaluated for their antimicrobial potential against selected pathogenic microorganisms. The Salophen ligand was prepared through the condensation reaction of salicylaldehyde and 1,2-benzenediamine in ethanolic medium, followed by complexation with Copper sulfate to obtain the corresponding Copper salophen complex. The synthesized ligand and metal complex were characterized using Fourier Transform Infrared (FT-IR) spectroscopy and Electrospray Ionization Mass Spectrometry (ESI-MS). Spectral analysis confirmed the formation of the Schiff base and coordination of azomethine nitrogen and phenolic oxygen atoms with the Copper ion. The FT-IR spectra exhibited characteristic ν(C=N) stretching vibrations within the range of 1601–1620 cm⁻¹, while mass spectral data validated the molecular composition of the synthesized compounds. The antimicrobial activity of the synthesized compounds was investigated by agar well diffusion technique against Gram-positive bacteria (Staphylococcus spp. and Enterococcus spp.), Gram-negative bacteria (Klebsiella spp. and Escherichia coli), and fungal species (Aspergillus spp.). Experimental results demonstrated that the Copper salophen complex exhibited enhanced antimicrobial activity compared with the free ligand. The Copper complex showed moderate antibacterial activity against Enterococcus spp. with a zone of inhibition of 15 mm, whereas the Salophen ligand exhibited 12 mm inhibition. Antifungal studies also revealed slight inhibitory activity of the Copper complex against Aspergillus spp. with a 4 mm zone of inhibition.

The enhanced biological activity of the Copper complex may be attributed to chelation effects, increased lipophilicity, and improved penetration through microbial cell membranes according to Overtones concept and Tweedy’s chelation theory. The findings indicate that Copper salophen complexes possess promising antimicrobial properties and may serve as potential candidates for the development of new metal-based antimicrobial agents against resistant microbial pathogens.

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