• T R Rao

      Articles written in Journal of Chemical Sciences

    • Some lanthanide metal complexes of n-isonicotinamidosalicylaldimine

      T R Rao I A Khan R C Aggarwal

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      Trivalent lanthanide complexes of the type K[ML2] whereM=La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III) and Dy(III) and H2L=N-isonicotinamidosalicyladimine, have been prepared and characterised. The nephelauxetic ratio (β), covalency (δ) and bonding parameter (b2) of K[NdL2] have been calculated. Infrared spectral studies reveal that N-isonicotinamidosalicylaldimine acts as a dibasic tridentate ligand. A coordination number six has been proposed for the lanthanide metal ions.

    • Some trivalent lanthanide complexes of I-tyrosine hydrazide

      T R Rao I A Khan

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      Tyrosine hydrazide (TH) has been found to form complexes of the types [M(TH)3Cl2]Cl [M=La(III), Pr(III), Nd(III)] and [M′(TH)2Cl2]Cl [M′=Sm(III), Eu(III), Gd(III) and Dy(III)]. The complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared, electronic and PMR spectral studies. The nephelauxetic ratio (β), covalency (δ) and bonding parameter, (b1/2) of [Nd(TH)3Cl2]Cl have been calculated. Infrared spectral studies reveal that TH acts as a neutral bidentate ligand. Coordination numbers of eight around La(III), Pr(III) and Nd(III) and six around Sm(III), Eu(III), Gd(III) and Dy(III) have been proposed in the complexes.

    • Complexes of some lanthanides with acetoneisonicotinoyl hydrazone: A synthetic and spectral study

      Genda Singh Madhu R Srivastava Pariti S S J Sastry T R Rao

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      Some trivalent lanthanide complexes of acetone isonicotinoylhydrazone (AINH), having the empirical formula Ln(AINH)3Cl3, where Ln=La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III) and Y(III) were prepared. Elemental analyses, molar conductance, magnetic susceptibility, IR, electronic,1H,13C and139La NMR spectra of the complexes have been examined. It has been found that AINH behaves as a neutral bidentate ligand coordinating through the carbonyl oxygen and azomethine nitrogen. Temperature-dependence of the molar absorptivity and the metal coordination number has been established by the electronic spectra of Nd(AINH)3Cl3 recorded over the 28–80°C range.

    • Coordinating behaviour of a tridentate Schiff-base in its normal and hemi-acetal forms towards some 3d-metal ions

      Pariti S S J Sastry T R Rao

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      Metal complexes of the empirical formula [M(Hpbzgh)2], where H2pbzgh=pyridoxalN-benzoylglycyl hydrazone and M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II), have been synthesized and their structures studied by electronic, IR,1H and13C NMR spectra. IR and NMR spectral data indicate uninegative tridentate coordinated ligand bonding through hydrazidic carbonyl/imidolic oxygen, azomethine nitrogen and phenolate oxygen with its pyridoxal moiety in hemi-acetal as well as normal forms. Magnetic and electronic spectral data suggest distorted octahedral geometry for the Mn(II), Co(II), Ni(II) and Cu(II) complexes.

    • Studies on some rare earth metal complexes: Ten- and six-coordinated complexes of an unsymmetrical aminoacid derivative

      P A Kumar T R Rao

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      2,4-Dihydroxybenzaldehyde(N-benzoyl)glycyl hydrazone, H3 dhbbgh, has been synthesized and characterized. Rare earth metal complexes of the empirical formulae, [Ln(H3dhbbgh)2Cl2]Cl.nH2O and [Ln(dhbbgh)(H2O)2], where Ln=La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III) and Y(III) have been synthesized and characterized by elemental analyses, molar conductances, magnetic susceptibilities, electronic, infrared and NMR spectral studies. Various bonding parameters (β, b1/2, %δ andη) calculated from the electronic spectra of Pr(III), Nd(III), Sm(III) and Dy(III) complexes suggest a weak covalent bond between the metal and ligand. The theoretical oscillator strengths (Pcalcd) and a set of three intensity parameters (Tλ=2,4.6) computed from the Judd-Ofelt equation are found to be in good agreement with experimental values. On the basis of the spectral profiles of the hypersensitive transitions (4I9/24G5/2,2G7/2) in the Nd(III) complexes, coordination numbers ten and six have been proposed for the Ln(III) ions in the adduct and deprotonated complexes respectively.

    • Synthesis and characterization of the complexes of some transition metals with 2-acetyl pyridine (N-benzoyl) glycyl hydrazone

      R K Lonibala T R Rao

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      Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) with 2-acetyl pyridine (N-benzoyl) glycyl hydrazone(2-ApBzGH) have been synthesized and characterized by elemental analyses, molar conductances, magnetic susceptibility, IR, electronic, ESR,1H,13C and113Cd NMR spectral and X-ray diffraction studies. IR and NMR data suggest the tridentate nature of the ligand coordinating as a neutral species in the addition complexes and as a uninegative species in the deprotonated complexes. The presence of more than one isomer of the ligand has been established by1H NMR spectra of the ligand and complexes recorded over the 298–396 K range. The X-ray powder diffraction patterns of [Cd(2-ApBzGH)Cl]Cl and [Cu(2-ApBzGH)Cl(H2O)2]Cl are indexed for orthorhombic and tetragonal crystal systems respectively.

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