Metal complexes having the composition M(Bipy)Cl2 (where, M = Cu(II), Ni(II) and Co(II); Bipy = 2,2-bipyridyl) are reacted with 2-acetylthiophene thiosemicarbazone (ATT) to produce heteroleptic transition metal complexes with molecular formula [M(Bipy)ATT]. The complexes are characterized by mass spectra, molar conductivity, infrared and electronic spectra. Electrochemical behaviour of these metal complexes was investigated by cyclic voltammetric studies. The metal complexes show quasi reversible cyclic voltammetric responses for the Cu(II)/Cu(I) couple. The binding properties of these complexes with calf-thymus DNA have been investigated by using absorption spectrophotometry. Metal complexes are screened for their antibacterial activity by using agar well diffusion method against pathogenic bacterial strains viz. Escherichia coli and Staphylococcus aureus. Antibacterial activity of the present complexes are comparable with the activity of ciprofloxacin. The Cu(Bipy)Cl2 complex inhibits bacteria more strongly than any other complex. The Ni(Bipy)ATT complex shows more activity than the parent complex, Ni(Bipy)Cl2.
A series of new 2,2` -bipyridine/1,2-dithiolate transition metal complexes has been synthesised and characterised. As 1,2-dithiolate ligands 1,2-dithiooxalate (dto) and 1,2-dithiosquarate (dtsq) were used. It follows from the IR spectra that the multidentate dithiolate ligands coordinate exclusively via their sulfur atoms forming an MN2S2 coordination sphere. The central metal ions (M) are Cu2+, Ni2+, Pd2+, Pt2+, and Zn2+. The complex [CuII(bpy)(dto)] could be studied by EPR spectroscopy and was measured as powder, diamagnetically diluted in the isostructural [NiII(bpy)(dto)] host structure. The spin density contribution calculated from the experimental parameters is compared with the electronic situation in the frontier orbitals, namely in the semi-occupied SOMO of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT).