http://nopr.niscair.res.in/handle/123456789/4073 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/4105 Title: Determination of dynamic dissociation constant of chromium-poly(N-vinyl­pyrro­lidone) complex by the radiotracer technique <br/> <br/>Authors: Nayak, Dalia; Banerjee, Anupam; Ghosh, Kingshuk; Das, Ayan; Lahiri, Susanta <br/> <br/>Abstract: The binding ability of polyvinylpyrrolidone (PVP) with chromium in its different oxidation states has been investigated. The complexation of PVP towards Cr(III) and Cr(VI) labeled with ⁵¹Cr radionuclide has been studied with the dialysis technique. The stability of the complexes has been examined by measuring the dynamic dissociation constant from the slope of the plot of ln{Cr(VI)/(III)-PVP} versus time. It has been observed that both Cr(VI)-PVP and Cr(III)-PVP complexes are most stable at <i>p</i>H 7. However, the Cr(III)-PVP complex is more stable than the Cr(VI)-PVP complex at all <i>p</i>H values. This study shows the comparative stability of the complexes of the two different species of chromium with PVP, which may be useful in radiopharmaceutical sciences. <br/> <br/>Page(s): 672-675 Tue, 28 Apr 2009 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/4104 Title: Extraction chromatographic method of preconcentration and separation of cadmium(II) with high molecular mass liquid cation exchanger, Versatic 10 <br/> <br/>Authors: Mandal, B; Ghosh, N <br/> <br/>Abstract: A selective method has been developed for the extraction chromatographic separation of Cd(II) with Versatic 10 coated on silanised silica gel. The quantitative extraction has been achieved from 0.1<i style="">M</i> acetate buffer at the optimum <i style="">p</i>H of 6.0-7.5. The effects of <i style="">p</i>H, flow-rate and stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to Cd(II) has been determined. Cd(II) has been separated from synthetic binary and multi-component mixtures containing various metal ions associated with it in ores and alloy samples. The method effectively permits sequential separation of Cd(II) from synthetic quaternary mixture containing its congeners, Cu(II), Sn(II), Hg(II), Cu(II), Sn(II) and Bi(III), of the same analytical group. The method is found effective for removal and recovery of Cd(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of Cd(II) has been suggested. <br/> <br/>Page(s): 668-671 Tue, 28 Apr 2009 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/4103 Title: Syntheses, crystal structures and antibacterial activities of two zinc complexes derived from 4-bromo-2-[(2-methylaminoethylimino)- methyl]phenol <br/> <br/>Authors: Hui, Rui-Hua; Zhou, Peng; You, Zhong-Lu <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="chmetcnv"> Reactions of the tridentate Schiff base, 4-bromo-2-[(2-methylaminoethylimino)methyl]phenol with zinc acetate and zinc chloride, afford two polynuclear zinc complexes, [Zn{ZnL(μ₂-acetato-<i style="">O</i>,<i style="">O</i>)(μ₂-acetato-<i style="">O</i>,<i style="">O’</i>)}₂] (<b>1</b>), and [Zn₂L₂Cl₂] (<b style="">2</b>) respectively Complex (<b style="">1</b>) is a centrosymmetric trinuclear zinc compound, in which the two terminal Zn atoms are five-coordinate in a distorted square-pyramidal geometry, while the central Zn atom is six-coordinate in an octahedral geometry. Complex (<b style="">2</b>) is a dinuclear zinc compound, which possesses a two-fold rotation axis. In (<b style="">2</b>), one Zn atom is four-coordinate in a tetrahedral geometry, and the other one is six-coordinate in an octahedral geometry. The antibacterial activities of the Schiff base and the two complexes have also been tested. <b style=""></b> </smarttagtype> <br/> <br/>Page(s): 663-667 Tue, 28 Apr 2009 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/4102 Title: Extending the phenyl-cyclopentadienyl rule <br/> <br/>Authors: Gutman, Ivan; Jeremić, Svetlana; Petrović, Vladimir <br/> <br/>Abstract: By examining the energy effect of cyclic conjugation in individual rings of acenaphthylene- and fluoranthene-type polycyclic conjugated molecules, a peculiar regularity - named the “PCP rule” - was recently discovered [Gutman, I, Đurđević J & Balaban A T, <i>Polycycl Arom Comp</i>, 29 (2009) 3]. According to the PCP rule, a six-membered ring which is connected to the five-membered ring by a single carbon-carbon bond increases the cyclic conjugation in the five-membered ring. An analogous regularity also exists in polycyclic conjugated species possessing an odd-membered ring of size greater than five. <br/> <br/>Page(s): 658-662 Tue, 28 Apr 2009 22:58:59 GMT