Synthesis, Spectroscopic and Antimicrobial Studies of Lead (II) Complexes of Schiff Bases Derived From Amino Acids and Isatins

ABSTRACT

A new series of lead (II) complexes have been synthesized with Schiff bases derived from isatins and amino acids. These ligands act as bidentate species and coordinate to the metal atom through the azomethine nitrogen and carboxylate oxygen atom via deprotonation. The synthesized complexes have been characterized by elemental analysis, conductance measurements, and molecular weight determinations. The mode of bonding of the complexes has been suggested on the basis of infrared, UV-visible, and ¹H- and ¹³C-NMR spectroscopy, and probable structures have been assigned to these complexes. Few representative ligands and metal complexes have also been screened for their antifungal and antibacterial activities. Molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compound, [Pb(L³)₂], to substantiate the proposed structures.

KEYWORDS:

• amino acids
• antimicrobial activity
• isatins
• lead (II) complexes
• Schiff base
• spectral studies

ACKNOWLEDGMENTS

The authors are thankful to the dean of Faculty of Engineering & Technology, Mody Institute of Technology and Science, Deemed University, Lakshmangarh, Sikar, for providing necessary facilities and financial support. The authors are also thankful to the head of SAIF, Panjab University, Chandigarh, for providing elemental analysis and NMR facilities.

Notes

s = singlet, d = doublet, t = triplet, m = multiplet.

^a See Table 1 for identities of ligands L¹H–L³H and their corresponding lead (II) complexes.