Kotha Laxma Reddy

Synthesis, characterization, DNA-binding, and DNA-photocleavage properties of [Co(bpy)2(7-NO2-dppz)]3+, [Co(dmb)2(7-NO2-dppz)]3+, and [Co(phen)2(7-NO2-dppz)]3+ complexes: (7-nitro-dppz = 7-nitro dipyrido[3,2-a:2'-3'-c]phenazine; bpy = 2,2'-bipyridine; dmb = 4,4'-dimethyl-2,2'-bipyridine; phen = 1,10-phenanthroline) and their toxicity on different microorganisms.

The polypyridyl ligand 7-Nitro dipyrido[3,2-a:2′-3′-c]phenazine (7-Nitro-dppz) and its complexes [Co(bpy)2(7-NO2-dppz)]3+(1) (bpy = 2,2′-bipyridine), [Co(dmb)2(7-NO2-dppz)]3+(2), (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)2(7-NO2-dppz)]3+(3) (phen = 1,10-phenanthroline) were synthesized and characterized by UV/VIS, IR, elemental analysis, 1H and 13C-NMR, and mass spectra. The binding properties of the three complexes to CT-DNA were investigated by different spectroscopic methods and viscosity measurements and DNA cleavage assay. The experimental results suggest that these complexes bind to CT-DNA through an intercalative mode. Also, the three complexes promote the photocleavage of plasmid pBR-322 DNA under irradiation. Toxicological effects of the selected complexes were estimated with different microorganisms.

DNA-binding and photocleavage properties of Ru(II) polypyridyl complexes with DNA and their toxicity studies on eukaryotic microorganisms.

Four Ru(II) polypyridyl complexes, [Ru(bpy)2(7-NO2-dppz)]2+, [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(phen)2(7-NO2-dppz)]2+, and [Ru(phen)2(7-CH3-dppz)]2+ (bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), (7-Nitro-dppz = 7-Nitro dipyrido[3,2-a:2′-3′-c]phenazine, 7-CH3-dppz = 7-Methyl dipyrido[3,2-a:2′-3′-c]phenazine), have been synthesized and characterized by IR, UV, elemental analysis, 1H NMR, 13C-NMR, and mass spectroscopy. The DNA-binding properties of the four complexes were investigated by spectroscopic and viscosity measurements. The results suggest that all four complexes bind to DNA via an intercalative mode. Under irradiation at 365 nm, all four complexes were found to promote the photocleavage of plasmid pBR 322 DNA. Toxicological effects of the selected complexes were performed on industrially important yeasts (eukaryotic microorganisms).

Synthesis, characterization, and DNA binding of ruthenium(II) complexes with 2-benzo[b] furan-2-yl-1H-imidazo[4,5f][1,10]phenanthroline as an intercalative ligand

DNA-binding properties of a number of ruthenium complexes with different polypyridine ligands are reported. The new polypyridine ligand BFIP (=2-benzo[b] furan-2-yl-1H-imidazo[4,5-f][1,10]phenanthroline) and its ruthenium complexes [Ru(bpy)2BFIP]2+ (bpy = 2,2′-bipyridine), [Ru(dmb)2BFIP]2+ (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Ru(phen)2BFIP]2+ (phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, mass spectra, IR, UV-Vis, 1H- and 13C-NMR, and cyclic voltammetry. The DNA binding of these complexes to calf-thymus DNA (CT-DNA) was investigated by spectrophotometric, fluorescence, and viscosity measurements. The results suggest that ruthenium(II) complexes bind to CT-DNA through intercalation. Photocleavage of pBR 322 DNA by these complexes was also studied, and [Ru(phen)2BFIP]2+ was found to be a much better photocleavage agent than the other two complexes.

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.

Synthesis, DNA Binding, DNA Photocleavage and Antimicrobial Activity of [Co(bpy)2DMHBT]3+, [Co(dmb)2DMHBT]3+ and [Co(phen)2DMHBT]3+ Complexes

ABSTRACT Cobalt(III) polypyridyl complexes of the type [Co(bpy)2DMHBT]3+, [Co(dmb)2DMHBT]3+ and [Co(phen)2DMHBT]3+ (where DMHBT = 11,13-dimethyl-13H-4,5,9,11,14-hexa aza-benzo[b] triphenylene-10,12-dione; bpy = 2,2′-bipyridine; dmb = 4,4′-dimethyl-2,2′-bipyridine; phen = 1,10-phenanthroline) have been synthesized and fully characterized by elemental analysis, IR, UV-Visible spectra, 1H, 13C-NMR and Mass spectra. The results of absorption and emission titrations as well as thermal temperature and Viscosity measurement studies reveal that [Co(bpy)2DMHBT]3+, [Co(dmb)2DMHBT]3+, and [Co(phen)2DMHBT]3+ are moderate to strong binders of Calf Thymus DNA. An experimental result indicates that the three complexes can intercalate in to DNA base pairs. Under the identical conditions the super-coiled pBR 322 DNA photo-cleavage activities of these three cobalt(III) complexes follow the order:[Co(phen)2DMHBT]3+ > [Co(bpy)2DMHBT]3+ > [Co(dmb)2DMHBT]3+. These complexes are also found to have good antimicrobial activity.

Study of the interaction between ruthenium(II) complexes and CT-DNA: synthesis, characterisation, photocleavage and antimicrobial activity studies

Two polypyridyl ligands 6-fluro-3-(1H-imidazo [4,5-f] [1,10]-phenanthroline-2-yl)-4H-chromen-4-one (FIPC), 6-chloro-3-(1H-imidazo [4,5-f] [1,10]-phenanthroline-2-yl)-4H-chromen-4-one (ClIPC) polypyridyl ligands and their Ru(II) complexes [Ru(bipy)2FIPC]2+(1), [Ru(dmb)2FIPC]2+(2), [Ru(phen)2FIPC]2+(3), [Ru(bipy)2ClIPC]2+(4), [Ru(dmb)2ClIPC]2+(5) and [Ru(phen)2ClIPC]2+(6) ((bipy = 2,2′-bipyridine, dmb = 4,4′-dimethyl-2,2′-bipyridine and phen = 1,10-phenanthroline) have been synthesised and characterised by elemental analysis, Mass spectra, IR, 1H and 13C-NMR. The DNA-binding of the six complexes to calf-thymus DNA (CT-DNA) has been investigated by different spectrophotometric, fluorescence and viscosity measurements. The results suggest that 1–6 complexes bind to CT-DNA through intercalation. The variation in binding affinities of these complexes is rationalised by a consideration of electrostatic, steric factors and nature of ancillary ligands. Under irradiation at 365 nm, the three complexes have also been found to promote the photocleavage of plasmid pBR 322 DNA. Inhibitor studies suggest that singlet oxygen (1O2) plays a significant role in the cleavage mechanism of Ru(II) complexes. Thereby, under comparable experimental conditions [Ru(phen)2FIPC]2+(3), [Ru(phen)2ClIPC]2+(6) cleaves DNA more effectively than 1, 2, 4 and 5 complexes do. The Ru(II) polypyridyl complexes (1–6) have been screened for antimicrobial activities.

Synthesis, characterization, photocleavage, antimicrobial activity and DNA binding of [Co(bpy)2MHPIP]3+, [Co(dmb)2MHPIP]3+, and [Co(phen)2MHPIP]3+ complexes

4-Methyl-2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline) (MHPIP) and its complexes [Co(bpy)2MHPIP]3+ (1) (bpy = 2,2′-bipyridine), [Co(dmb)2MHPIP]3+ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)2MHPIP]3+ (3) (phen = 1,10-phenanthroline) have been synthesized and characterized by UV/VIS, IR, EA, 1H, 13C-NMR, and mass spectra. The binding of the three complexes with calf-thymus-DNA (CT-DNA) has been investigated by absorption and emission spectroscopy, DNA-melting techniques, viscosity measurements, and DNA cleavage assay. The spectroscopic data and viscosity results indicate that these complexes bind to CT-DNA via an intercalative mode. The complexes also promote photocleavage of plasmid pBR322 DNA and were screened for antimicrobial activity.

Synthesis, DNA Binding, and DNA Photocleavage of the Cobalt(III) Complexes [Co(bpy)2MDPPZ]3+, [Co(dmb)2MDPPZ]3+, and [Co(phen)2MDPPZ]3+and their Antimicrobial Activity

The ligand 7-methyl dipyrido[3,2-a:2′-3′-c]phenazine (MDPPZ) and its complexes [Co(bpy)2MDPPZ]3+(1) (bpy = 2,2′-bipyridine), [Co(dmb)2MDPPZ]3+ (2), (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)2MDPPZ]3+(3) (phen = 1,10-phenanthroline) have been synthesized and characterized by UV-VIS, IR, EA, 1H, and 13C-NMR and mass spectra. The interactions of the three complexes with CT-DNA have been investigated by absorption and emission spectroscopy, DNA melting, viscosity measurements, and DNA cleavage assay. The experimental results suggested that these complexes bind to CT-DNA through an intercalative mode. Three complexes have also been found to promote the photo cleavage of plasmid pBR-322 DNA under irradiation. The inhibition studies suggest that the oxygen species are mainly responsible for the photocleavage by these complexes. Further, all the three Co(III) complexes synthesized were screened for their antimicrobial activity.

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.