Bivalent metal complexes having the composition M(Phen)Cl2 (where, M = Cu(II), Ni(II) and Co(II); Phen = 1,10-Phenonthroline) are reacted with 2-acetylthiophene-4-phenyl-3-thiosemicarbazone (ATPT) to produce ternary complexes with molecular formula [M(Phen)(ATPT)Cl2] H2O. The complexes are characterized using physical (molar conductivity) and spectral (mass spectra, infrared and electronic spectroscopies) methods. Electrochemical behavior of complexes was uncovered using cyclic voltammetry. DNA binding properties of the complexes are determined by using absorption UV-Visible spectrophotometry. Metal complexes are screened for their antibacterial activity by using agar well diffusion method against pathogenic bacterial strains viz. Gram–ve such as Escherichia coli, Klebsiella Pneumonia and Gram+ve such as Staphylococcus aureus, Bacillus cereus. The [Ni (Phen)(ATPT)Cl2] 0.5 H2O complex inhibits bacteria more stronger than any other complex. HIGHLIGHTS Ternary Metal Complexes with 1,10 Phenanthroline and 2-Acetylthiophene-4-phenyl-3-thiosemicarbazone are synthesized The complexes are characterized using physico-chemical, spectral and electrochemical methods DNA binding properties of the complexes are determined Metal complexes are screened for their antibacterial activity The [Ni (Phen)(ATPT)Cl2] 0.5 H2O complex inhibits bacteria more effectively GRAPHICAL ABSTRACT

Metallo-hydrazones having the formula [M(IBAH)2] (where, M = Ni(II), Cu(II) and Zn(II); IBAH = p-Isopropylbenzaldehyde acetoylhydrazone) are prepared and confirmed on the basis of physico-chemical and spectral analyses. Conductivity data revealed that the complexes are non-electrolytes. Metal-DNA interactions are investigated using absorption spectrophotometry. Binding constant (Kb) data revealed that the copper complex interact DNA more strongly than other complexes. Antibacterial activity studies indicated higher activity for complexes than the metal free hydrazone ligand. The copper compound displays higher activity. DNA binding constants are correlated with the activity of metal compounds in this article.

The hydrazone ligand, 2-formylpyridine benzoylhydrazone (FPBH) has been used to synthesize copper(II), nickel(II) and cobalt(II) complexes and characterized by elemental analyses, mass spectra, molar conductivity data IR, UV-visible spectroscopy. The complexes are found to have general formula M(FPBH)2 (where, M = Cu(II), Ni(II) and Co(II). Further the copper complex is investigated using ESR spectra. The spin Hamiltonian, orbital reduction and bonding parameters are calculated for the complex. The complex, Ni(FPBH)2 is structurally characterized based on single crystal X-ray crystallography. The complex crystallizes in monoclinic space group P21/c with a = 11.2632(2) Å, b = 8.8958(2) Å, c = 23.0834(5) Å, α = 90°, β = 90.858(2)°, γ = 90°, V = 2312.59(8) Å3 and Z = 4 with central Ni(II) ion in distorted octahedral structure coordinated by two tridentate FPBH ligand. The interactions of these complexes with calf thymus DNA have been investigated using absorption spectrophotometry. The copper complex binds more strongly than either nickel or cobalt complexes.

Heterolyptic metal complexes having the composition M(Bpy)Cl2 (where, M = Cu(II), Ni(II) and Co(II); Bpy = 2,2′-bipyridyl) were reacted with 2-acetylthiophene-4-phenyl-3-thiosemicarbazone (ATPT) to produce bivalent metal complexes with molecular formula M(Bpy)(ATPT)Cl·H2O. The complexes were characterized using physical (molar conductivity) and spectral (mass spectra, infrared and electronic spectroscopies) methods. Electrochemical behaviour of the complexes was revealed using cyclic voltammetry. The Cu(II)/Cu(I) couple complexes show a quasi-reversible cyclic voltammetric responses. The DNA binding properties of complexes were determined through absorption UV-visible spectrophotometry. Furthermore, the agar well diffusion method was used to screen the metal(II) complexes for their antibacterial activity against pathogenic bacterial strains, namely Gram negative strains such as Escherichia coli and Klebsiella pneumonia and Gram positve strains such as Staphylococcus aureus and Bacillus cereus. The synthesized Cu(Bpy)(ATPT)]Cl·H2O complex strongly inhibits bacteria compared with other complexes.

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