48 research outputs found

    1H NMR Study of the Enantioselective Binding of λ- and Δ-[Ru(bpy)2(m-bpy-GHK)]Cl2 to the Deoxynucleotide Duplex d(5'-C1G2C3G4A5A6T7T8C9G10C11G12-3')2

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    The interaction of the diastereomeric complexes Λ- and Δ - [Ru(bpy)2(m - GHK)]Cl2, (GHK = glycine-histidine-lysine) to the deoxynucleotide duplex d(5'-CGCGAATTCGCG-3')2 was studied by means of 1H NMR spectroscopy. The diastereomers interact with the oligonucleotide duplex differently. The Δ - [Ru(bpy)2 (m - GHK)]Cl2 is characterized by major groove binding close to the central part of the oligonucleotide, with both the peptide and the bipyridine ligand of the complex involved in the binding. The λ - [Ru(bpy)2 (m - bpy - GHK)]C2 binds loosely, approaching the helix from the minor groove. The NMR analysis shows that the peptide (GHK) binding has a determinative role in the interactions of both diastereomers with the oligonucleotide

    Synthesis, characterization and antibacterial activity studies of new 2‑pyrral‑L‑amino acid Schif base palladium (II) complexes.

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    Three new 2-pyrral amino acid Schif base palladium (II) complexes were synthesized, characterized and their activity against six bacterial species was investigated. The ligands: Potassium 2-pyrrolidine-L-methioninate (L1), Potassium 2-pyrrolidine-L-histidinate (L2) and Potassium 2-pyrrolidine-L-tryptophanate (L3) were synthesized and reacted with dichloro(1,5- cyclooctadiene)palladium(II) to form new palladium (II) complexes C1, C2 and C3, respectively. 1 NMR, FTIR, UV–Vis,elemental analysis and conductivity measurements were used to characterize the products. The antibacterial activities of the compounds were evaluated against Gram-positive Staphylococcus aureus (S. aureus, ATCC 25923), methicillin-resistant Staphylococcus aureus (MRSA, ATCC 33591), Staphylococcus epidermidis (S. epidermidis, ATCC 12228) and Streptococcus pyogenes (S. pyogenes, ATCC 19615) and, gram-negative Pseudomonas aeruginosa (P. aeruginosa, ATCC 27853) and Klebsiella pneumoniae (K. pneumoniae, ATCC 13883) using the agar well difusion assay and microtitre plate serial dilution method. The palladium complexes were active against the selected bacteria with the imidazole ring containing complex C2 and indole heterocyclic ring containing complex C3 showing the highest activity

    Mixed ligand Ru(II) complexes with 2,2′-bipyridine and 2-(2′-pyridyl)quinoxaline

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    The synthesis and the physical properties of a new series of Ru(II) mixed ligand tris chelate complexes of the type [LxRu (bpy)3-x], where L = 2-(2′-pyridyl) quinoxaline and bpy = 2,2′-bipyridine, are reported. The complexes were fully characterized by NMR spectroscopic techniques, Electrospray Mass Spectroscopy, UV-visible spectra and elemental analyses. The complex [RuL3](PF6)2 probably has the mer conformation due to the bulky shape of the L on the side of quinoxaline. The complex [RuL2(bpy)](PF6)2 was isolated as a mixture of all three possible geometric isomers, while the [RuL(bpy)2](PF6)2 in only one isomer as theoretically expected. Photoinduced dissociation of one molecule of the ligand L from the complex [RuL3](PF6)2 upon exposure to room light has been studied by 1H NMR and UV-vis Spectroscopies. © 1999 Elsevier Science Ltd. All rights reserved

    Metal complexes of the Schiff base ligand L=1,2-bis (2′-pyridylmethyleneimino)benzene with Ni2, Fe2 and Cu2 and their reactions with bridged bidentate ligands. The crystal structure of the complex [NiL(H2O)2]Cl2

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    The preparation and the characterization of Ni2 and Fe2 complexes of the neutralN4 non-macrocyclic Shiff base ligandL=12-bis- (2′-pyridylmethyleneimino)benzene of formulae FeLCl2 and [NiL(H2O)2]Cl2 are reported The structure of the Ni complex[NiL(H2O)2]Cl2has been determined by X-ray diffraction methods The nickel atom has a six coordinate NiN4O2 chromophore with distorted octahedral coordination The ligand L acts as tetradentate chelatewith the ligated atoms in an essentially planar arrangement around the metal with the remaining axial coordination sites occupied by water ligands In addition a series of ligand-bridged LMCl2 oligomeric complexes of the type { [LME]Cl2}n (M=NiFeCu and E=pyrazine44′-bipyridine14-dicyanobenzene14-cyanopyridine)have been synthesized and characterized by elemental analysissolid state conductivitymagnetic susceptibility measurements and IRUV-VIS and ES-MS spectroscopic techniques Doping of these complexes with iodine exhibited conductivities in the solid state comparable to similar dimethylglyoxime derivative complexes © 1998 Elsevier Science Ltd All rights reserved
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