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Oxovanadium(IV) complexes have been synthesized and characterized the general composition [VOL(A)], where H2L = salicylidene-o-aminothiophenol A1 = bis(benzylidene)ethylenediamine, A2 = bis(acetophenone)ethylenediamine, A3 = 2,2'-bipyridylamine, A4 = bis(benzylidene) - 1,8-diaminonaphthalene, A5 = thiophene-o-carboxaldeneaniline and A6 = thiophene-o-carboxaldene-p-anisidine. Spectral studies indicate that the oxovanadium(IV) complexes assume a six-coordinate octahedral geometry. The antibacterial activities of the complexes against Salmonella typhi, Escherichia coli and Serratia mercescens are higher as compared to the free ligands, vanadyl sulphate, and the control (DMSO) but of moderate activity as compared to the standard drug (tetracycline).

*Seven new copper(II) complexes of type [Cu(A)(L)]ÁH 2 O (A = sparfloxacin, ciprofloxacin, levofloxacin, gatifloxacin, pefloxacin, ofloxacin, norfloxacin; L = 5-[(3-chlorophenyl)diazenyl]-4-hydroxy-1,3-thiazole-2(3H)-thione) were synthesized and characterized using elemental and thermogravimetric analyses, and electronic, electron paramagnetic resonance (EPR), Fourier transform infrared and liquid chromatography-mass spectroscopies. Tetrahedral geometry around copper is assigned in all complexes using EPR and electronic spectral analyses. All complexes were investigated for their interaction with herring sperm DNA utilizing absorption titration (K b = 1.27-3.13 × 10 5 M À1) and hydrodynamic volume measurement studies. The studies suggest the classical intercalative mode of DNA binding. The cleavage reaction on pUC19 DNA was monitored by agarose gel electrophoresis. The results indicate that the Cu(II) complexes can more effectively promote the cleavage of plasmid DNA. The superoxide dismutase mimic activity of the complexes was evaluated by nitroblue tetrazolium assay, and the complexes catalysed the dismutation of superoxide at pH = 7.8 with IC 50 values in the range 0.597-0.900 μM. The complexes were screened for their in vitro antibacterial activity against five pathogenic bacteria. All the complexes are good cytotoxic agents and show LC 50 values ranging from 5.559 to 11.912 μg ml À1. All newly synthesized Cu(II) complexes were also evaluated for their in vitro antimalarial activity against Plasmodium falciparum strain (IC 50 = 0.62-2.0 μg ml À1).

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A series of 1,3,5-trisubstituted pyrazolines based homoleptic Ru(III) complexes of type [Ru(L 1-7 ) 3 ]$(PF 6 ) 3 (L 1-7 ¼ pyrazoline ligands) have been synthesized and characterized by elemental analysis, electronic spectroscopy, conductance measurements, thermogravimetric analysis (TGA), electron paramagnetic resonance (EPR), fourier transform infrared (FT-IR) spectroscopy and liquid chromatography mass spectroscopy (LC-MS). Octahedral geometry around ruthenium has been assigned in all complexes using EPR and electronic spectral analysis. All complexes have been investigated for their interaction with Herring Sperm (HS) DNA utilizing an absorption titration (K b ¼ 2.42-6.07 Â 10 5 M À1 ) and viscosity measurement study. The studies suggest the classical intercalative mode of binding. The DNA-binding property of the Ru(III) complexes was also investigated theoretically using a molecular docking study and suggests an intercalation binding mode between the complex and nucleotide base pairs. A cleavage study on pUC19 DNA has been performed by agarose gel electrophoresis. The results indicated that the Ru(III) complexes can more effectively promote the cleavage of plasmid DNA. The free ligands and their complexes have been evaluated for cytotoxicity activity against S. pombe cells at a cellular level. A comparative study of cellular level cytotoxicity values of the all compounds indicates that the metal complexes show better activity against S. pombe cells compared to the pyrazoline ligands. The complexes have been screened for their in vitro antibacterial activity against two Gram(+ve) and three Gram(Àve) microorganisms. Ru(III) complexes are good in vitro cytotoxic agents and 50% lethal concentration (LC 50 ) values are in range of 5.296-7.925 mg mL À1 . All newly synthesized Ru(III) complexes have been also evaluated for their in vitro antimalarial activity against Plasmodium falciparum strain [inhibition concentration (IC 50 ) ¼ 0.54-0.92 mg mL À1 ].