Mynam Shilpa

Ruthenium(II) ethylenediamine complexes with dipyridophenazine ligands: synthesis, characterization, DNA interactions, and antiproliferative activities

Ruthenium(II) complexes, [Ru(en)2dppz]2+ (1), [Ru(en)2qdppz]2+ (2), [Ru(en)2acdppz]2+ (3), and [Ru(en)2actatp]2+ (4), have been synthesized and characterized by IR, 1H, 13C-NMR and LC–MS. The interactions of these complexes with calf thymus (CT) DNA have been investigated by absorption, emission, viscosity, thermal denaturation, and circular dichroism. These techniques reveal that the complexes bind strongly to DNA. The apparent binding constants for the complexes decrease from 1 to 4 and are in the order of 8.5 ± 0.2 × 105 M−1 (1), 7.3 ± 0.8 × 105 M−1 (2), 4.3 ± 0.3 × 105 M−1 (3), and 7.5 ± 0.5 × 104 M−1 (4). The plot of log K versus log [Na+] yield slopes of −1.47, −1.44, −1.36, and −1.24 for 1, 2, 3, and 4, respectively. These complexes promote the photocleavage of pBR322 DNA. Cytotoxicities of these complexes suggest their possible anticancer activity.

Synthesis, Characterization Luminiscence Studies and Microbial Activity of Ethylenediamine Ruthenium (II) Complexes with Dipyridophenazine Ligands

Three symmetric ligands 7-methyl dipyrido-[3,2-a;2′,3′-c]phenazine (dppz-CH3), 7-nitro dipyrido-[3,2-a;2′,3′-c]phenazine (dppz-NO2) and benzo[i]dipyrido-[3,2-a;2′,3′-c]phenazine (dppn) and their ruthenium(II) complexes [Ru(en)2(L)][ClO4]2 (en= ethylenediamine), L= dppz-CH3, dppz-NO2 and dppn have been synthesized and characterized by IR, 1H, 13C NMR and Mass spectra. The interactions of these complexes with calf thymus DNA have been investigated by spectrophotometric, spectrofluorimetric, circular dichroism, viscosity and thermal denaturation studies. As the planar extension of the intercalative ligand increases, the interaction of the complex with DNA increases, indicating that the size and shape of the intercalalative ligand has a marked effect on the strength of interaction. The plot of log K versus log [Na+] yield a slope of -1.26, -1.53, -1.60 for the complexes 1, 2 and 3 respectively. These three complexes have been found to promote the cleavage of plasmid pBR 322 DNA upon irradiation.

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: [Co(en)2(py)2]3+ and [Co(en)2(mepy)2]3+.

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity.

DNA-binding and Photocleavage Studies of Ethylenediamine Cobalt(III) and Ruthenium(II) Mixed Ligand Complexes

,(en=ethylene-diamine, pyip =(pyip = 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]phenanthroline),(aip = 2-(9-anthryl)-1H-imidazo[4,5,-f][1,10] phenanthroline) have been synthe-sized and characterized. The interaction of these complexes with calf thymus DNAwas investigated using absorption (UV/vis) and emission spectroscopy, viscositymeasurements as well as DNA melting and plasmid DNA cleavage studies. Theexperimental results show that the four complexes can bind to DNA in an intercala-tion mode. The DNA-binding affinity of complex

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: and

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity.

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: [Co(en)2(py)2]3

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity.