Pyrazolyl Pd(II) complexes containing triphenylphosphine: Synthesis and antimycobacterial activity

Abstract

Abstract Complexes of the type trans-[PdCl<inf>2</inf>(HL)(PPh<inf>3</inf>)], where HL = pyrazole (1); 3,5-dimethylpyrazole (2); 4-nitropyrazole (3); 4-iodopyrazole (4) and PPh<inf>3</inf> = triphenylphosphine, were synthesized and characterized by elemental analyses, infrared and ¹H NMR spectroscopies. Single-crystal X-ray diffraction determination on 3·0.9 CHCl<inf>3</inf> and 4 showed that the coordination geometry around Pd(II) is nearly square-planar, with the chloro ligands in a trans configuration. In vitro antimycobacterial evaluation demonstrated that compound 4 displayed a minimum inhibitory concentration (MIC) of 7.61 ± 2.18 μM, being superior to the values observed for some commonly used antituberculosis drugs and other metal-based complexes.