Panneerselvam Anitha

Synthesis, characterization, DNA interaction, antioxidant and anticancer activity of new ruthenium(II) complexes of thiosemicarbazone/semicarbazone bearing 9,10-phenanthrenequinone.

A new series of octahedral ruthenium(II) complexes supported by tridentate ligands derived from phenanthrenequinone and derivatives of thiosemicarbazide/semicarbazide and other co-ligands have been synthesized and characterized. DNA binding experiments indicated that ruthenium(II) complexes can interact with DNA through non-intercalation and the apparent binding constant value (Kb) of [RuCl(CO)(PPh₃)(L₃)] (3) at room temperature was calculated to be 2.27 × 10(3)M(-1). The DNA cleavage studies showed that the complexes have better cleavage of pBR 322 DNA. Antioxidative activity proved that the complexes have significant radical scavenging activity against free radicals. Cytotoxic activities showed that the ruthenium(II) complexes exhibited more effective cytotoxic activity against selected cancer cells.

Ruthenium(II) complexes containing quinone based ligands: Synthesis, characterization, catalytic applications and DNA interaction

1,2-Naphthaquinone reacts with amines such as semicarbazide, isonicotinylhydrazide and thiosemicarbazide in high yield procedure with the formation of tridentate ligands HL(n) (n=1-3). By reaction of ruthenium(II) starting complexes and quinone based ligands HL(n) (n=1-3), a series of ruthenium complexes were synthesized and characterized by elemental and spectroscopic methods (FT-IR, electronic, (1)H, (13)C, (31)P NMR and ESI-MS). The ligands were coordinated to ruthenium through quinone oxygen, imine nitrogen and enolate oxygen/thiolato sulfur. On the basis of spectral studies an octahedral geometry may be assigned for all the complexes. Further, the catalytic oxidation of primary, secondary alcohol and transfer hydrogenation of ketone was carried out. The DNA cleavage efficiency of new complexes has also been tested.

Ruthenium(II) 9,10-phenanthrenequinone thiosemicarbazone complexes: synthesis, characterization, and catalytic activity towards the reduction as well as condensation of nitriles

The ligands 9,10-phenanthrenequinone-N4-substituted thiosemicarbazones (HL1–3) and their ruthenium(II) complexes were synthesized and characterized by elemental and spectroscopic methods. The ligands are tridentate, monobasic chelating ligands with O, N, and S as the donor sites and are in the thiol form in all the complexes. Catalytic studies showed that all the complexes displayed good catalytic activity towards the reduction of nitriles and also the condensation of nitriles with 2-aminoalcohol under solvent-free conditions. Graphical Abstract

Palladium(II) 9,10-phenanthrenequinone N-substituted thiosemicarbazone/semicarbazone complexes as efficient catalysts for N-arylation of imidazole

A series of palladium complexes, [PdCl(L1–4)] (1–4) (L1 = 9,10-phenanthrenequinone thiosemicarbazone, L2 = 9,10-phenanthrenequinone methylthiosemicarbazone, L3 = 9,10-phenanthrenequinone phenylthiosemicarbazone, and L4 = 9,10-phenanthrenequinone semicarbazone), have been synthesized and characterized by elemental analyses, UV–vis, FT-IR, 1H and 13C NMR, and ESI-Mass spectroscopic methods. The catalytic efficiency of the synthesized complexes was examined against N-arylation of imidazole. The system works well with the electron-rich, -neutral, and -deficient aryl halides to afford the products in good to excellent yields. Sterically congested aryl halides and heteroaryl halides have also been used as substrates to provide N-arylated heterocycles. In addition, this methodology can be applicable to other substrates with N-containing heterocycles. Graphical abstract Palladium(II) 9,10-phenanthrenequinone N-substituted thiosemicarbazone/semicarbazone complexes as efficient catalysts for N-arylation of imidazole

Nickel(II) complexes containing ONS donor ligands: Synthesis, characterization, crystal structure and catalytic application towards C-C cross-coupling reactions

AbstractNickel(II) complexes containing thiosemicarbazone ligands [Ni(L)2] (1-3) (L = 9,10-phenanthrenequinonethiosemicarbazone (HL1), 9,10-phenanthrenequinone-N-methylthio semicarbazone (HL2) and 9, 10-phenanthrenequinone-N-phenylthiosemicarbazone (HL3)) have been synthesized and characterized by elemental analysis and spectroscopic (IR, UV-Vis, 1H, 13C-NMR and ESI mass) methods. The molecular structures of complexes 1 and 2 were identified by means of single-crystal X-ray diffraction analysis. The analysis revealed that the complexes possess a distorted octahedral geometry with the ligand coordinating in a uni-negative tridentate ONS fashion. The catalytic activity of complexes towards some C–C coupling reactions (viz., Kumada-Corriu, Suzuki-Miyaura and Sonogashira) has been examined. The complexes behave as efficient catalysts in the Kumada-Corriu and Sonogashira coupling reactions rather than Suzuki-Miyaura coupling. Graphical AbstractNickel(II) complexes bearing 9,10-phenanthrenequinone N-substituted thiosemicarbazone ligands were synthesized and characterized. The X-ray crystal structure of the complexes revealed a distorted octahedral geometry around the metal centre. These nickel complexes exhibited better catalytic activity in Kumada-Corriu and Sonogashira cross-coupling reactions than in Suzuki-Miyaura reaction.