ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis, characterization and antibacterial activity studies of new 2-pyrral-L-amino acid Schiff base palladium (II) complexes

Eunice A. Nyawade, Martin O. Onani, Samantha Meyer, and Phumuzile Dube

Department of Chemistry, University of the Western Cape, Bellville, South Africa

E-mail: enyawade@jkuat.ac.ke

Received: 29 May 2019  Accepted: 30 October 2019

Abstract:

Three new 2-pyrral amino acid Schiff base palladium (II) complexes were synthesized, characterized and their activity against six bacterial species was investigated. The ligands: Potassium 2-pyrrolidine-L-methioninate (L1), Potassium 2-pyrrolidine-L-histidinate (L2) and Potassium 2-pyrrolidine-L-tryptophanate (L3) were synthesized and reacted with dichloro(1,5-cyclooctadiene)palladium(II) to form new palladium (II) complexes C1, C2 and C3, respectively. ¹H NMR, FTIR, UV–Vis, elemental analysis and conductivity measurements were used to characterize the products. The antibacterial activities of the compounds were evaluated against Gram-positive Staphylococcus aureus (S. aureus, ATCC 25923), methicillin-resistant Staphylococcus aureus (MRSA, ATCC 33591), Staphylococcus epidermidis (S. epidermidis, ATCC 12228) and Streptococcus pyogenes (S. pyogenes, ATCC 19615) and, gram-negative Pseudomonas aeruginosa (P. aeruginosa, ATCC 27853) and Klebsiella pneumoniae (K. pneumoniae, ATCC 13883) using the agar well diffusion assay and microtitre plate serial dilution method. The palladium complexes were active against the selected bacteria with the imidazole ring containing complex C2 and indole heterocyclic ring containing complex C3 showing the highest activity.

Keywords: Schiff bases; Antibacterial; Palladium; Chelates; Amino acids; Pyrrole; Imidazole; Indole

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00986-5

Chemical Papers 74 (11) 3705–3715 (2020)