33 research outputs found

    Mixed valency in cerium oxide crystallographic phases: Determination of valence of the different cerium sites by the bond valence method

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    We have applied the bond valence method to cerium oxides to determine the oxidation states of the Ce ion at the various site symmetries of the crystals. The crystals studied include cerium dioxide and the two sesquioxides along with some selected intermediate phases which are crystallographically well characterized. Our results indicate that cerium dioxide has a mixed-valence ground state with an f-electron population on the Ce site of 0.27 while both the A- and C-sesquioxides have a nearly pure f^1 configuration. The Ce sites in most of the intermediate oxides have non-integral valences. Furthermore, many of these valences are different from the values predicted from a naive consideration of the stoichiometric valence of the compound

    Novel Pd(II)-salen complexes showing high in vitro anti-proliferative effects against human hepatoma cancer by modulating specific regulatory genes

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    Item does not contain fulltextWe have reported the synthesis of a novel salen ligand and its mononuclear Pd-salen complexes derived from 2-{[2-hydroxy-3-{[(E)-(2-hydroxyphenyl)methylidene]amino}propyl)imino]methyl}phen ol. The newly synthesized and isolated Pd(II) complexes have been identified and fully characterized by various physico-chemical studies viz., elemental analyses, IR, UV-Vis, (1)H, (13)C NMR spectroscopy, electron spray ionization mass spectrometry (ESI-MS) and TGA/DTA studies. The molecular structure of the salen ligand has been ascertained by single-crystal XRD and it is coordinated to Pd(II) ion through two nitrogen and two oxygen atoms. The UV-Vis data clearly suggest a square-planar environment around both the Pd(II) ions. The DNA binding studies of the synthesized compounds has been investigated by electron spectroscopy and fluorescence measurements. The results suggest that Pd(II) complexes bind to DNA strongly as compared to the free ligand. The free salen ligand and its Pd(II) complexes have also been tested against human hepatoma cancer cell line (Huh7) and results manifested exceptional anti-proliferative effects of the Pd(II) complexes. The anti-proliferative activity of Pd(II) complexes has been modulated by specific regulatory genes
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