Synthesis, Structural, and Antibacterial Studies of Some Transition Metal Complexes Derived from Thiosemicarbazone and Semicarbazone

A series of metal complexes of Pd(II), Pt(II), Rh(III), Ir(III), and Ru(III) with thiosemicarbazone and semicarbazone of 2-acetyl thiophene have been synthesized. Their structures were determined on the basis of elemental analyses; molar conductance; magnetic susceptibility measurements; and IR, 1H NMR, and electronic spectral studies. On the basis of molar conductance, the complexes may be formulated as [M(L)2]Cl2 and [M'(L)2Cl2]Cl [where M = Pd(II), Pt(II) and M' = Rh(III), Ir(III), and Ru(III)] due to their 1:2 and 1:1 electrolytic nature. On the basis of IR, 1H NMR, and electronic spectral studies, an octahedral geometry has been assigned for Rh(III), Ir(III), and Ru(III), while square planar geometry has been assigned for the Pd(II) and Pt(II) complexes. The synthesized ligands and their complexes have been screened for bactericidal activity against several bacterial species (i.e., B. macerans, A. aureus, E. coli), and it is shown that the metal complexes act as more active antimicrobial agents than the uncomplexed ligands from which they derive.