Syntheses, characterization and in vitro antiamoebic activity of new Pd(II) complexes with 1-N-substituted thiocarbamoyl-3,5-diphenyl-2-pyrazoline derivatives

Reaction of neutral NS bidentate ligands, 1-N-substituted thiocarbamoyl-3,5-diphenyl-2-pyrazolines, isolated by cyclization of chalcone with N-4-substituted thiosemicarbazide of aromatic amines (1-8), with [Pd(DMSO)(2)Cl-2] (DMSO = dimethylsulfoxide) leads to the formation of new complexes of the type [Pd(L)Cl-2] (1a-8a). The structures of the compounds were elucidated by UV, IR, H-1 NMR, C-13 NMR and ESI-MS spectral data and thermogravimetric analysis and their purities were confirmed by elemental analyses. The antiamoebic activity of these complexes was evaluated by microdilution method against HM1:1MSS strain of Entameoba histolytica and the results were compared with the standard drug, metronidazole. Generally palladium complexes showed better activity than their corresponding ligands. Compound 3a showed better IC50 = 0.05 mu M as compared to metronidazole IC50 = 1.82 mu M. (c) 2006 Published by Elsevier Masson SAS.