Synthesis, Characterization, and Antimicrobial Activity oF The Ligand 3-Methylpyrazole- 4-Carboxaldehyde Thiosemicarbazone and Its Pd(II) Complex

Abstract

The synthesis and characterization of a new palladium(II) complex [Pd(MePhPzTSC)₂] and its corresponding ligand 3-methylpyrazole-4-carboxaldehyde thiosemicarbazone (MePhPzTSC) are described. The bidentate ligand is coordinated to Pd(II) through the azomethine nitrogen atoms and sulfur in the form of thiol by deprotonation of the NH-C = S. The antimicrobial activity of these new compounds was evaluated against gram-negative (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus and Bacillus thuringiensis) bacteria and two yeast strains (Candida albicans and Saccharomyces cerevisiae). Coordination of the ligand to the metallic ion showed improved antimicrobial activity compared to the free ligand. For the gram-positive bacteria the antimicrobial activity of the complex was higher than that of the positive control used.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the following free supplemental files: Additional figures and tables]

GRAPHICAL ABSTRACT

Keywords:

• Thiosemicarbazone
• palladium complexes
• antimicrobial activity

Acknowledgments

The authors thank the Dirección de Investigación Sede Bogotá (DIB, Bogota Research Directorate) for funding this project (code number 201010016735) and the Vicerrectoría de Investigación for financial support for the translation of this manuscript through the “Convocatoria Nacional Fortalecimiento de la Visibilidad de Producción Académica mediante el apoyo para traducción de estilo de artículos de investigación 2011–2012,” both from the National University of Colombia. We also thank Professor Milton Crosby, Faculty of Science in the Department of Pharmacy at the National University of Colombia, for providing the strains used for the bioassays.