C.N. Sudhamani

Synthesis, DNA binding and cleavage studies of Ni(II) complexes with fused aromatic N-containing ligands

The three Ni(II) complexes of fused aromatic N-containing ligands such as [Ni(bnp)(3)](PF(6))(2) (1), [Ni(phen)(2)(bnp)](PF(6))(2) (2) and [Ni(bpy)(2)(bnp)](PF(6))(2) (3) (where bnp=dibenzo(b)1,8-naphthpyridine, phen=1,10-phenanthroline and bpy=bipyridine) were synthesized and structurally characterized. Elemental analysis, magnetic and spectroscopic data suggested octahedral geometry for all the complexes. Binding of these complexes with (ds)DNA were analyzed by absorption spectra, viscosity and thermal denaturation studies. Detailed analysis revealed that the metal complexes intercalates into the DNA base stack as intercalator. The oxidative cleavage activities of the complexes were studied with supercoiled (SC)pUC19 DNA by using gel electrophoresis, and the results show that complexes have potent nuclease activity.

Novel complexes of Co(III) and Ni(II) containing peptide ligands: Synthesis, DNA binding and photonuclease activity

The new cobalt(III) and nickel(II) complexes of the type [M(L)2(H2O)2](n)(+) (where M = Co(III) or Ni(II) ion, n = 3 for Co and 2 for Ni, L = peptides Fmoc. Ala-val-OH (F-AVOH), Fmoc-Phe-Leu-Ome (F-PLOMe) and Z-Ala-Phe-CONH2 (Z-APCONH2)) were synthesized and structurally characterized by FTIR, (1)H NMR, elemental analysis and electronic spectral data. An octahedral geometry has been proposed for all the synthesized Co(III) and Ni(II) metal complexes. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. Detailed analysis revealed that the metal complexes intercalates into the DNA base stack as intercalator. The photo induced cleavage studies shows that the complexes possess photonuclease property against pUC19 DNA under UV-Visible irradiation.

Synthesis, DNA binding, and cleavage studies of Co(III) complexes with fused aromatic NO/NN-containing ligands.

Four new Co(III) complexes, namely [Co(cq)3](PF6)3, [Co(phen)2(cq)](PF6)3, [Co(bnp)3] (PF6)3, and [Co(phen)2(bnp)](PF6)3 (where cq = chromeno[2,3-b]quinoline, phen = 1,10-phenanthroline and bnp = dibenzo[b,g][1,8]naphthyridine), were synthesized and structurally characterized. Spectroscopic data suggested an octahedral geometry for all the complexes. Binding studies of these complexes with double-stranded (ds)DNA were analyzed by absorption spectra, viscosity, and thermal denaturation studies. The results revealed that the metal complex intercalates into the DNA base stack as intercalator. The oxidative cleavage activities of the complexes were studied with supercoiled pUC19 DNA using gel electrophoresis and the results show that the complexes have potent nuclease activity.

Synthesis of Functionalized Iron Oxide Nanoparticle with Amino Pyridine Moiety and Studies on Their Catalytic Behavior

Aim: The main objective of this paper is to study the synthesis of functionalized iron oxide nanoparticle and its reactivity towards chromene synthesis Study design: Functionalized iron oxide nanoparticle study. Place and duration of study: Department of Studies and Research in Industrial Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta, between December 2009 and July 2010. Methodology: This paper describes synthesis of stable functionalized iron oxide nanoparticles through surface modification of magnetic iron oxide nanoparticles by amino pyridine. Iron oxide nanoparticles were synthesized by co-precipitation method and the surface modification process was achieved by treating the nanoparticles with (chloro propyl trimethoxy silane) CPTS and aminopyridine. The developed functionalized iron oxide nanoparticle was evaluated as the catalyst for synthesis of chromones under MW irradiation conditions. Results: The catalysts were magnetically recovered and reusable without significant loss of their catalytic efficiency. To receive morphological and structural information on the obtained functionalized nanoparticle, the samples were analyzed by X-ray diffraction (XRD) measurements, FTIR and scanning electron microscopy (SEM) imaging. All synthesized chromene derivatives were characterized using analytical techniques such as IR, H NMR, and mass spectroscopy. Also the identity of these compounds was easily established by comparison of their melting point with those of reported samples. Conclusion: In summary, we have developed a new magnetically recyclable and Research Article American Chemical Science Journal, 1(3): 97-108, 2011 98 efficient functionalized magnetic nano catalyst for the chromene synthesis. Magnetic nanoparticle catalyst achieves a simple separation of catalyst without filtration including high yield in product.

Novel iron phenanthroline-based photosensitizers for antimicrobial PDT: synthesis, DNA binding and photo-induced DNA cleavage activity

The chemistry of Fe(II) complexes showing efficient light-induced DNA cleavage activity, binding propensity to calf thymus DNA and antibacterial photodynamic therapy has been summarized in this article. Complexes of formulation [Fe(mqt)(B)2](PF6)(1)–(3), where mqt is 2-thiol-4-methylquinoline and B is N,N-donor heterocyclic base, viz. 1,10-phenanthroline, dipyrido[3,2-d:2′,3′-f]quinoxaline and dipyrido[3,2-a:2′,3′-c]phenazine have been prepared and characterized. The DNA-binding behaviors of these three complexes were explored by absorption spectra, viscosity measurements and thermal denaturation studies. The DNA binding constants for complexes (1), (2) and (3) were determined to be 1.9 × 103, 3.4 × 104 and 8.1 × 104 M−1, respectively. The experimental results suggest these complexes interact with DNA through groove-binding mode. The complexes show significant photocleavage of supercoiled DNA proceeds via a type-II process forming singlet oxygen as the reactive species. Antimicrobial photodynamic therapy was studied using photodynamic antimicrobial chemotherapy assay against Escherichia coli and all complexes exhibited significant reduction in bacterial growth on photoirradiation.

Synthesis, Characterization, DNA Binding, and Cleavage Activity of New Co(III) and Ru(II) Complexes of Substituted Quinolines

The cobalt(III) and ruthenium(II) complexes of the type [M(L)2]n+ (M = Co(III) or Ru(II) ion, n = 3 for Co and 2 for Ru, L = 2-thiol/seleno 4-methylquinoline) were synthesized and structurally characterized. The spectral and magnetic data suggested octahedral geometry for all the complexes. DNA binding behaviors of these complexes with calf thymus DNA (CT-DNA) have been investigated by absorption spectra, viscosity, and thermal denaturation methods. The metal complexes intercalates into the DNA base stack. The oxidative cleavage activities of the complexes shows that the complexes act as potent nucleases.