Structural and biological studies of mononuclear palladium(II) complexes containing N-substituted thiosemicarbazones

New complexes of Pd(II) with N-substituted thiosemicarbazone (1)–(3) have been synthesised and characterised by elemental analyses, IR, electronic, 1H NMR spectroscopies. The electrochemical behaviour of the complexes has been tested by using cyclic voltammetry. The crystal structures of the complexes have been determined by single crystal X-ray diffraction technique. In all the complexes the thiosemicarbazone ligand is coordinated to palladium through ONS mode. The complex 1 crystallises in the monoclinic space group P21/c with two molecules per unit cell, has the dimensions of a = 9.4390(19) Å, b = 10.645(2) Å, c = 13.668(3) Å, α = 90°, β = 91.43° and γ = 90°. The complex 3 crystallises in the monoclinic space group P21/c with four molecules per unit cell, has the dimensions of a = 14.119(3) Å, b = 11.155(2) Å, c = 18.503(4) Å, α = 90°, β = 112.02° and γ = 90°. The new complexes have been tested for their antibacterial activity against various pathogenic bacteria. From this study, it was found out that the activity of the complex 2 almost reaches the effectiveness of the conventional bacteriocide Streptomycin.

Graphical abstractThe crystal structures of the complexes of the type [Pd(L)(PPh3)] (L = tridentate bibasic thiosemicarbazone ligand) have been determined by single crystal X-ray diffraction technique. In all the three complexes the ligands are coordinated in ONS fashion. All the new complexes have been screened for their antibacterial activities against various pathogenic bacteria.Figure optionsDownload full-size imageDownload as PowerPoint slide