DOI: https://doi.org/10.55373/mjchem.v26i5.101

Keywords: Antimicrobial activity; catalysis; dithiocarbamates; palladium complexes

Abstract

The catalytic and antibacterial activity of heteroleptic palladium (Pd) complexes bearing dithiocarbamates (DTC) moiety is described. Various spectroscopic techniques, including multinuclear nuclear magnetic resonance (NMR), Fourier Transform–Infrared (FT-IR), elemental analysis, and thermogravimetric analysis (TGA), were employed to characterize both DTC salt and heteroleptic Pd complexes. An excellent catalytic performance was observed in the C-H functionalization of benzo[h]quinoline to 10-methoxy benzo[h]quinoline in the presence of a sacrificial oxidant. The heteroleptic Pd complex provided an almost quantitative yield of product (89%) under a milder condition (50℃, 3 mol% Pd loading) and shorter reaction times (2 hrs). The antibacterial activity of DTC salt and heteroleptic Pd complexes was investigated against six bacterial strains: 4 Gram-negative [Escherichia coli, Salmonella thyphimurium, Klebsiella aerogenes, and Klebsiella pneumoniae] and 2 Gram-positive [Bacillus subtilis, and Bacillus cereus]. Herein, we highlight that the heteroleptic Pd complex exhibited more significant inhibition activity than the DTC ligand against Gram-negative bacteria as compared to Gram-positive bacteria. Further analysis showed that both tested compounds possessed moderate bacteriostatic (MIC) effects against all tested strains. The heteroleptic Pd complex's bactericidal (MBC) potency was more significant than the ligand's.