NOPR Collection:

Studies on synergistic extraction of Pd (II) using thiosemicarbazone derivative of 2-OHʹ naphthaldehyde and neutral donors

2013-08-21T16:42:29Z

Title: Studies on synergistic extraction of Pd (II) using thiosemicarbazone derivative of 2-OHʹ naphthaldehyde and neutral donors Authors: Banerjee, S; Basu, S Abstract: The synergistic extraction of Pd(II) from aqueous hydrochloric acid medium, using thi osemicarbazone derivative of 2-OHʹ naphthaldehyde in ethyl acetate has been investigated in the presence of various neutral donors like amines (TOA, Amberlite LA-2 and Adogen-464) and phosphorus oxides (TOPO, phosphonate, TBPO, TPPO and TBP). The overall equilibrium constant (log K) for the ternary species [Pd(A)CIS], where S is donor and A is the ligand, has been calculated for various systems. The values of synergistic co-efficient and adduct formation constant in organic phase (β) for the amine donors are found to be greater than those for the phosphorus oxide donors. Among the amines, the trend is found to be quarternary> tertiary> secondary and among the phosphorus oxide donors, it is phosphonate > trioctyl phosphine oxide (TOPO) > tributyl phosphine oxide (TBPO) > triphenyl phosphine oxide (TPPO) >tributyl phosphate (TBP). Effects of pH variation and nature of various diluents on the synergistic extraction of Pd (II) have also been studied. The procedure has been applied to the estimation of Pd (II) in rock samples. Page(s): 1914-1917

Poly(vinyl chloride) membrane containing zirconium(IV)selenomolybdate inorganic ion exchanger as dysprosium(III)ion selective electrode

2013-08-22T16:41:16Z

Title: Poly(vinyl chloride) membrane containing zirconium(IV)selenomolybdate inorganic ion exchanger as dysprosium(III)ion selective electrode Authors: Gupta, A P; Verma, G L; Agarwal, Himanshu Abstract: Poly(vinyl chloride) supported tetracycline sorbed zirconium(IV) selenomolybdate chelating inorganic exchange membrane has been employed for the determination of dysprosium(III) ion. The membrane electrode shows a Nernstain response for Dy(III) over a wide concentration range (l.0×10^-1 M - 5×10^-5 M) with a slope of 18.3 mV per decade of concentration. The detection limit is 3.8×10^-5 M. The electrode is found to possess adequate stability and specific selectivity for Dy(III) over the other closely trivalent lanthanide metal ions with a response time of ~15 s. The sensor can also be used in partially non-aqueous medium, e.g., acetone/alcohol having 5- 10% (v/v) contents. Its working pH range is 2-9. It is successfully applied for the direct determination of Dy³⁺ in meta borate rock and as an indicator electrode in potentiometric titrations of dysprosium ion with 2-4 % experimental error. Page(s): 1910-1913

Synthesis, spectral and magnetic studies of some polynuclear, mixed-ligand complexes of iron and cobalt with 3-mercaptopropionic acid

2013-08-21T16:42:21Z

Title: Synthesis, spectral and magnetic studies of some polynuclear, mixed-ligand complexes of iron and cobalt with 3-mercaptopropionic acid Authors: Baranwal, B P; Gupta, Tarkeshwar; Singh, Atresh K Abstract: Some mixed-ligand, trinuclear complexes of mixed-valence iron (III, III, II) and dinuclear cobalt(II) have been synthesized by enforced substitution of acetate ions from their respective acetate complexes. The isolated products of the types [Fe₃O(OOCR)₃(OOCR'SH)₃] and [Co(OOCR)(OOCR'SH)]₂(where R = C₇H₁₅, C₁₁H₂₃ or C₁₅H₃₁ and R' = -CH₂CH₂-) are mixed (carboxylato)(mercaptocarboxylato) complexes. These have been characterized by microanalytical data and infrared, UV visible and Mossbauer spectra. Non-electrolytic behaviour and polynuclear nature of the complexes have been assessed from their low conductance and high molecular weight data. The octahedral environment around both the metals has been suggested on the basis of UV-visible and magnetic moment data. Mossbauer studies reveal two resolved quadrupole doublets due to Fe(II) and Fe(III) confirming the valence-localised classification of the iron compounds. Page(s): 1905-1909

Heterobi nuclear cobalt-oxomoI ybdenumthiocyanate complexes of dithiocarbamates or 8-quinolinol

2013-08-22T16:41:11Z

Title: Heterobi nuclear cobalt-oxomoI ybdenumthiocyanate complexes of dithiocarbamates or 8-quinolinol Authors: James, S; Nagaraja, K S Abstract: The heterobinuclear complexes of [CoMoO₂(NCS)(L)₃(H₂O)](L=diethyldithiocarbamate, 4-morpholinyldithiocarbamate or 8- quinolinol) are prepared by the interaction of ammonium molybdate with ammonium thiocyanate in the presence of hydrazinium sulphate and cobalt (II) nitrate with the respective ligands in DMF. The magnetic moment, EPR and PES data suggest the presence of molybdenum(V) and low-spin cobalt(III).The crystal field splitting parameters have been evaluated from the electronic spectral data. The infrared spectra suggest the presence of N-bonded thiocyanate ligand (2040 and 780 cm^-1)dithiocarbamate ligands (1500 and 960 cm^-l) and (Mo=O) (910cm^-l) in the molecule. The extensive splitting in each peak observed in the ¹H NMR spectra of the complexes indicate the restricted rotation of the alkyl side chain of the bidentate dithiocarbamate groups. The redox behaviour of the complexes in DMF is discussed from the cyclic voltammetry data. The thermal decomposition and infrared spectral studies confirm the presence of coordinated water molecule. The proposed structure consists of an octahedral cobalt(III) and an octahedral oxomolybdenum(V) bridged by an oxo and a thiocyanate groups. Page(s): 1900-1904