Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10-phenanthroline family of ligands: DNA binding and photocleavage studies

DNA binding and photocleavage characteristics of a series of mixed-ligand complexes of the type [M(phen)2LL]n+ (where M = Co(III), Ni(II) or Ru(II), LL = 1,10-phenanthroline (phen), phenanthroline-dione (phen-dione) or dipyridophenazine (dppz) andn = 3 or 2) have been investigated in detail. Various physico-chemical and biochemical techniques including UV/Visible, fluorescence and viscometric titration, thermal denaturation, and differential pulse voltammetry have been employed to probe the details of DNA binding by these complexes; intrinsic binding constants (Kb) have been estimated under a similar set of experimental conditions. Analysis of the results suggests that intercalative ability of the coordinated ligands varies as dppz>phen>phen-dione in this series of complexes. While the Co(II) and Ru(II) complexes investigated in this study effect photocleavage of the supercoiled pBR 322 DNA, the corresponding Ni(II) complexes are found to be inactive under similar experimental conditions. Results of detailed investigations carried out inquiring into the mechanistic aspects of DNA photocleavage by [Co(phen)2(dppz)]3+ have also been reported

Antimicrobial activity and corrosion inhibition property of Schiff bases derived from Imidazole

311-318Schiff base ligands such as methyl 4-[(2-butyl-4-chloro-5-formyl-1H-imidazol-1-yl)methyl]benzoate thiosemicarbazone (L1) and 2-butyl-4-chloro-5-formylimidazole 2,4-dinitrophenylhydrzone (L2) are designed and synthesized via the reaction between methyl 4-[(2-butyl-4-chloro-5-formyl-1H-imidazol-1-yl)methyl]benzoate & thiosemicarbazide for L1and 2-butyl-4-chloro-5-formylimidazole & 2,4-dinitrophenylhydrazine for L2.Schiff bases are characterized by FT-IR, UV-visible, mass spectrometry,1H and 13C-NMR spectral studies. These ligands are individually tested for their antimicrobial activities for both gram positive and gram negative to examine their inhibition potential by well diffusion method. The corrosion inhibition property of all the three ligands L1, L2 & L3 on mild steel in 0.5 N HCl solution has been investigated at different concentrations and different temperatures by weight loss method. The biological activity of L2 has shown better activity against gram negative bacteria such as E-coli, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa and gram positive bacteria Staphylococcus aureus when compared to standard ligand L3. All the three ligands exhibit good corrosion inhibition property on mild steel in 0.5N HCl solution even at 0.1% concentration level and the rate of corrosion of mild steel is increased with increase of temperature of corrosion medium

Effect of Divalent Metal Dopant on the Structural and optical Properties of Tio 2 Quantum Dots

Abstract: In search of efficient materials for photo anode for DSSC, we made an attempt to prepare pure and transition metal (Zn 2+ , Cd 2+ and Ni 2+ ) doped Tio 2 simple microwave irradiated solvothermal method. The samples were characterized by structural and optical measurements. The particle size increased as the addition of dopant in the host TiO 2 lattices was increased in accordance with the crystallite size obtained by XRD analysis.UV-Vis spectral measurement suggests that addition of dopants in the host TiO 2 lattices helping to tune the optical band gap energy.The presence of small amount of dopants (5 mole % of Zn 2+ , Cd 2+ and Ni 2+ ) greatly affects the PL intensity of thehost TiO 2 nanocrystals. The doped nanocrystals(TiO 2 :Zn 2+ , TiO 2 :Cd 2+ and TiO 2 :Ni 2+ ) leads to strong enhancement in photoluminescence yield compared to pure TiO 2 and consequently to new useful materials for photonic applications

Oxidation of methionine by N-chloroacet-amide- Catalytic effect of formaldehyde

275-277Oxidation of -methionine(Met) by N-chloroacetamide (NCA) in buffered medium (pH ~ 7) in the presence and absence of formaldehyde is first order each in [NCAland [Met] and first order in [HCHO] when present. The observed rate constant shows a complex dependence on [H+]. The catalytic behaviour of HCHO could be explained by the fact that the rehybridization of sulphur atom from tetrahedral to trigonal bipyramidal structure is influenced by HCHO. The derived rate laws are consistent with the observed kinetics