New mixed ligand complexes of ruthenium(II) that incorporate a modified phenanthroline ligand: synthesis, spectral characterization and DNA binding

The hexafluorophosphate and chloride salts of two ruthenium(II) complexes, viz. [Ru(phen)(ptzo)2]2 and [Ru(ptzo)3]2+, where ptzo = 1,10-phenanthrolino[5,6-e]1,2,4-triazine-3-one (ptzo) - a new modified phenanthroline (phen) ligand, have been synthesised. These complexes have been characterised by infrared, UV-Vis, steady-state emission and1H NMR spectroscopic methods. Results of absorption and fluorescence titration as well as thermal denaturation studies reveal that both thebis- and tris-complexes of ptzo show moderately strong affinity for binding with calf thymus (CT) DNA with the binding constants being close to 105M-1 in each case. An intercalative mode of DNA binding has been suggested for both the complexes. Emission studies carried out in non-aqueous solvents and in aqueous media without DNA reveal that both [Ru(phen)(ptzo)2]2+ and [Ru(ptzo)3]2+ are weakly luminescent under these solution conditions. Successive addition of CT DNA to buffered aqueous solutions containing [Ru(phen)(ptzo)2]2+results in an enhancement of the emission. These results have been discussed in the light of the dependence of the structure-specific deactivation processes of the MLCT state of the metallo-intercalator with the characteristic features of its DNA interaction. In doing so, attempts have been made to compare and contrast its properties with those of the analogous phenanthroline-based complexes including the ones reported by us previously

Dehydrogenation of Isopropyl Alcohol on Zinc Molybdate (ZnMoO4)

851-85

Kinetics of Oxidation of Carbon Monoxide on Lanthanum Cobaltite

285-28

Catalytic Oxidation of Carbon Monoxide on Spinel Type Ferrites : Kinetic Characteristics

205-20

Catalytic Decomposition of Formic Acid on Zinc Molybdate

202-20

Kinetics of thermal decomposition of some metal oxalates

The thermal decomposition kinetics of oxalates of ZnII, NiII and ThIV have been studied in air by isothermal and non-isothermal thermogravimetry. The isothermal kinetic results suggest that the mechanism of decomposition of the zinc compound involves rapid nucleation followed by two dimensional growth in the acceleratory region, while in the case of thorium oxalate, the initial nucleation occurs by a chain mechanism on the surface of the reactant followed by the growth of the product from the surface towards the interior. The results on nickel oxalate could not be interpreted in an unambiguous manner. The activation energy and the frequency factor obtained from TG curves compare well with those obtained from the isothermal method. The activation energies for the dehydration of these oxalates have also been evaluated from the thermogravimetric curves

The Application of Biotechnologies to Groundnut, Arachis hypogaea L., with Special Reference to Developing Countries

Groundnut is the twelfth most important crop in the world, occupying some 19 million hectares in the warm temperate and tropical zones bounded by the 400 line of latitude. it is usually grown under rainfed conditions, but there are some areas in which it is grown under irrigation. World production in 1987 was 20 million tonnes in shell, most of which (12.8 million tonnes) was produced in Asia; of this amount, China produced 6.1 million tonnes while India produced 4.5 million tonnes. Africa produced 4.7 million tonnes. Worldwide, average yields by country range from 0.43 tonnesha to 4.60 tonnestha (FAO. 1987). Rainfed crops are often grown under low-input conditions, and even in those developing countries where fertilizers and pesticides are available on the market, many small farmers do not have sufficient resources to make use of them. There is thus a strong incentive todevelop varieties with pest and disease resistance, tolerance to poor soils, and the ability to yield under lowmoisture regimes