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

Complexes of the type trans-[PdCl2(HL)(PPh3)], where HL = pyrazole (1); 3,5-dimethylpyrazole (2); 4-nitropyrazole (3); 4-iodopyrazole (4) and PPh3 = triphenylphosphine, were synthesized and characterized by elemental analyses, infrared and 1H NMR spectroscopies. Single-crystal X-ray diffraction determination on 3·0.9 CHCl3 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.

Graphical abstractNew compounds of the type trans-[PdCl2(HL)(PPh3)] {HL = pyrazole (1); 3,5-dimethylpyrazole (2); 4-nitropyrazole (3); 4-iodopyrazole (4); PPh3 = triphenylphosphine} were synthesised, characterized and had their antimycobacterial activity evaluated. Compound 4 was the most active against Mycobacterium tuberculosis (MIC = 7.61 ± 2.18 μM).Figure optionsDownload full-size imageDownload as PowerPoint slide