Schiff bases: facile synthesis, spectral characterization and biocidal studies.

A family of Schiff bases was synthesized by the reactions of o-aminobenzoic acid and Knovenegal condensate of β-ketoesters in 1:1 ratio. The newly synthesized Schiff bases were characterized by Elemental analyses and spectral (FT-IR, UV–Vis and 1H-NMR) studies and the structures have been proposed tentatively. These compounds were subjected to study their biocidal efficacy against S. epidermidis, E. coli, B. cinerea and A. niger.

Ruthenium (II) complexes: Physico-chemical, spectroscopic, redox, microbial and DNA binding studies.

An octahedral ruthenium(II) Schiff base complexes of the type [Ru(CO)(Py)L] (L = dianion of the Schiff bases derived from acetoacetanilide with o-phenylenediamine and salicylaldehyde/ohydroxyacetophenone/ o-vanillin/2-hydroxy-1-naphthaldehyde) have been synthesized from the reactions of equimolar ratio of [Ru(CO)(PPh3)2(Py)] and Schiff bases in benzene. The formation of the Schiff base ligands and its complexes have been envisaged from IR, UV-VIS, 1H, 13C, 31P NMR, High resolution mass and Powder XRD studies. These spectral studies confirm an octahedral environment around the metal ion. The redox behaviour of the complexes has also been determined. The ligands, metal precursors and the complexes were tested for their efficiency towards antimicrobial activity. DNA binding studies (Herring Sperm DNA) were carried out for the complexes [Ru(CO)(Py)L1] and [Ru(CO)(Py)L2] using biochemical techniques such as UV-VIS, cyclic voltammetry and differential pulse voltammetry. These techniques paved the way to probe the details of their DNA binding abilities. Intrinsic binding constant have been estimated and it showed a moderate intercalative interactions than the other classical intercalators.

Synthesis and characterization of organosoluble ruthenium(ii) complexes bearing schiff base ligands: efficient reusable catalyst for the hydrogenation reactions.

Six new organosoluble ruthenium(II) complexes bearing dibasic tetradentate Schiff base ligands of the general formula [Ru(CO)(PPh3)(L)] (where L = dibasic tetradentate Schiff base ligands derived by condensing actetoacetanilide/acetoacetotoludide with o-aminophenol/oaminothiophenol/ o-aminobenzoic acid in 1:2 molar ratio in ethanolic medium) have been synthesized by reacting [RuHCl(CO)(PPh3)3] with the respective Schiff base ligands in 1:1 molar ratio. The complexes were characterized by physico-chemical and spectroscopic methods. An octahedral structure has been proposed tentatively for all the complexes. These ruthenium(II) complexes possess N2O2/N2S2 metal binding sites and act as a potential catalyst for the hydrogenation reactions. Organosoluble ruthenium(II) complexes have been used as catalysts in the hydrogenation of methoxy benzene and benzaldehyde. From the results it was observed that all the new six complexes proved to be better catalyst in the hydrogenation. All the ruthenium(II) complexes decomposes completely to form ruthenium metal, which in turn forms a active ruthenium hydride in the hydrogenation reaction. The reusability of the ruthenium catalysts have also been evaluated up to six consecutive runs, which does not show much variation in the conversion of the substrate.

Ruthenium (II) schiff base: Complexes, physico-chemical, spectrometric, microbial and dna binding and cleaving studies.

Stable ruthenium(II) carbonyl complexes having the general composition [Ru(CO) (PPh3)(py)(L)] (where L= bianion of tridentate Schiff bases (H2L1, H2L2 and H2L3)) were synthesized from the reaction of [RuHCl(CO)(PPh3)2(py)] with bidentate Schiff base ligands derived from condensation of isatin with o-aminophenol / o-aminothiophenol / o-aminobenzoic acid. The new complexes were characterized by elemental analysis, Mass spectra, IR, UV-Vis and 1H, 13C and 31P - NMR spectral data. The redox property of the complexes were studied by cyclic voltammetric technique. An octahedral geometry has been assigned tentatively for all the complexes. In all the above reactions, the Schiff bases replaces a hydride and chloride ion and PPh3 from the starting complexes, which indicate that the Ru–N bonds present in the complexes containing heterocyclic nitrogen bases are stronger than the Ru–P. These complexes were also subjected to study their biocidal activity against S. epidermidis and E. coli. Some of the complexes show higher efficiency when compared with the standard (Ciprofloxacin and Co-trimoxazole). DNA (Herring Sperm) binding behaviour of the complex [Ru(L1)(CO)(PPh3)(py)] has been studied by electronic spectra, cyclic voltammetric, differential pulse voltametric (DPV), circular dichorism and gel electrophoresis techniques.