An extractive spectrophotometric method has been developed for determination of molybdenum (VI) using newly synthesized reagent, N'-(2-hydroxybenzylidene)-3-(4-o-tolylpiperazin-1-yl) propanehydrazone (HTP). Molybdenum (VI) forms a yellow coloured water insoluble complex with HTP reagent in the acidic medium. The formed water insoluble complex is extractable in chloroform solvent and the complex shows maximum absorbance at max 389 nm. Under optimum conditions, Beer's law is obeyed in the range 1.918- 19.18 μg mL-1 of Molybdenum (VI). The molar absorptivity and Sandell's sensitivity for the complex is found to be 4.903 x 104 L mol-1 cm-1 and 0.02 μg. cm-2 respectively. The interference effect of various diverse ions has been studied. The complex shows 1:1 [Mo (VI): HTP] stoichiometry with stability constant of 8.29 x 106. The developed method has been employed for the determination of molybdenum (VI) in synthetic samples and in alloys.

An extraction-spectrophotometric method has been developed for determination of nickel using N'-(2-hydroxybenzylidene)-3-(4-o-tolylpiperazin-1-yl) propanehydrazide ( HTP ) as the new extractant. The reagent reacts with nickel (II) at pH = 9.0 and form a 1:1 yellow color complex, which is extracted into chloroform solvent. The complex showed maximum absorption wavelength at 382 nm. Beer’s law is obeyed in the concentration range of 1.17-12.91 μg.mL -1 with apparent molar absorptivity (0.72 x 10 4 L mol -1 cm -1 ) and Sandell’s sensitivity (0.008 μg/cm 2 /0.001 absorbance units). The tolerance limit of various foreign ions was investigated. The developed method was successfully applied for the determination of Nickel (II) in real water samples, alloy samples and Edible oil samples.

A new, slightly distorted octahedral complex of copper(II), square planar complexes of nickel(II) and palladium(II) with 2,4'-dibromoacetophenone thiosemicarbazone (DBAPTSC) are synthesized. The ligand and the complexes are characterized by FT-IR, FT-Raman, powder X-ray diffraction studies. The IR and Raman data are correlated for the presence of the functional groups which specifically helped in the confirmation of the compounds. In addition, the free ligand is unambiguously characterized by H-1 and C-13 NMR spectroscopy while the copper(II) complex is characterized by electron paramagnetic resonance spectroscopy (EPR). The g values for the same are found to be 2.246(g(1)), 2.012 (g(2)) and 2.005 (g(3)) which suggested rhombic distortions. The HOMO-LUMO band gap calculations for these compounds are found to be in between 0.5 and 4.0 eV and these compounds are identified as semiconducting materials. The synthesized ligand and its copper(II), nickel(II) and palladium(II) complexes are subjected to antitumour activity against the HepG2 human hepatoblastoma cell lines. Among all the compounds, nickel(II) complex is found to exert better antitumour activity with 57.6% of cytotoxicity. (C) 2014 Elsevier B.V. All rights reserved.

Synergistic extraction behaviour and selectivity in the separation of Zr(IV) and Hf(IV) were examined using synthesized 4-sebacoylbis(1phenyl-3-methyl-5-pyrazolone) (H2SbBP) in presence of various crown ethers (CEs), such as 18-crown-6 (18C6), dicylohexano-18crown-6 (DC18C6) and benzo-15-crown-5 (B15C5) from acidic chloride solutions.The preceding results demonstrate that Zr(IV) and Hf(IV) were synergistically extracted into chloroform with H2SbBP and crown ethers as ZrO(HSbBP)2-CE and HfO-(HSbBP)2-CE, respectively.The synergistic complexation strength of Zr(IV) and Hf(IV) was follows in order DC18C6 > 18C6 > B15C5.The addition of crown ethers to H2SbBP in chloroform not only enhance the extraction but also improves the selectivity in the separation of Zr(IV) and Hf(IV), especially, in presence of B15C5 (Zr(IV)/Hf(IV) = 13.18),where compared to H2SbBP alone (Zr(IV)/Hf(IV) =1.17) and other typical reports in literature.On the other hand the selectivity moderately decreased by the addition of DC18C6 and 18C6 to the synergistic solvent system.

Article history: Received on: 11/06/2013 Revised on: 29/06/2013 Accepted on: 11/07/2013 Available online: 30/07/2013 Three new chalcogenic thiosemicarbazones (3,4-difluoroacetophenone thiosemicarbazone(1), 2-bromo-4’chloroacetophenone thiosemicarbazone(2) and 2, 4’-dibromoacetophenone thiosemicarbazone(3) are synthesized by using a conventional one step processes in which the respective halo-substituted acetophenones are condensed with thiosemicarbazide to result in the formation of the product. The chalcogenic thiosemicarbazones are then characterized by the spectroscopic techniques like FT-IR, FT-Raman, UV-Vis, H and C NMR (F for 1), HRMS and LC-MS, TG-DTA. The compound 1 is unambiguously characterized by single crystal X-ray diffraction and is found to have monoclinic system. These compounds were further tested for their antimicrobial activity against some human pathogens like E. coli, B. subtilis, P. aureginosa and S. aureus. The MIC values have suggested that these are potential antimicrobial agents.

A simple, rapid, sensitive and inexpensive method has been developed for the determination of trace amounts of palladium(II) using 3,4-dihydroxybenzaldehydeisonicotinoylhydrazone (3,4-DHBINH). The metal ion gives a yellow colored complex with 3,4-DHBINH in acetate buffer of pH 3.0 with 1:1 (metal: ligand) composition. The complex shows maximum absorption at 380 nm. Beer’s law is obeyed in the range 0.5-20.0 ppm of Pd(II). The molar absorptivity, Sandell’s sensitivity and detection limit were found to be 0.53×104 L mol-1 cm-1, 0.02 μg cm-2 and 0.0948 μg mL-1, respectively. The correlation coefficient and regression coefficient of the Pd(II)-3,4-DHBINH complex were 1.08 and 0.04 respectively. Major cations and anions did not show any interference. Anti-microbial activity of the Pd(II)-3,4-DHBINH has been studied. The developed method has been successfully applied to the analysis of Pd(II) in spiked samples. Comparing the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method

Synthesized a new reagent 2, 6-Diacetylpyridine bis-4-phenyl-3-thiosemicarbazone (2, 6-DAPBPTSC) characterized and is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of molybdenum(VI) at pH 3.5 to form a yellowish orange colored 1:1 chelate complex. The absorbance was measured at a maximum wavelength, 500 nm. This method obeys Beer’s law in the concentration range 0.90–9.00 μg mL−1 and the correlation coefficient of Mo(VI)–2,6-DAPBPTSC complex is 0.954, which indicates an adequate linearity between the two variables with good molar absorptivity and Sandell’s sensitivity, 1.212 × 104 L mol−1cm−1, 0.0079 μg cm−2, respectively. The precision and accuracy of the method is checked with calculation of relative standard deviation (n = 5), 0.894% and the detection limit value is 0.0056 μg mL−1. The instability constant of the method has been calculated by Asmus’ method as 6.476 × 10–5, at room temperature. The interfering effect of various cations and anions has also been studied. The method was successfully applied for the determination of Mo(VI) in food and water samples. The validity of the present method was evaluated in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of the present method an inter comparison of the experimental values, using atomic absorption spectrometer.

Orthohydroxypropiophenoneisonicotinoylhydrazone (OHPINH) is proposed as a new sensitive reagent for the spectrophotometric determination of aluminum(III). OHPINH formed a greenish-yellow colored complex with aluminum(III) in buffer solutions of pH 1 to 3. The color in pH 2 was stable for more than 48 h. The complex solution has given maximum absorbance at 390 nm when the reagent was chosen as blank and the absorbance of the reagent at this wavelength is negligible; the molar absorptivity and Sandell’s sensitivity being 0.6371 ×104 L mol − 1 cm − 1 and 4.234 ×10 − 3 μg cm − 2, respectively. The system obeys Beer’s law in the range of 0.5–3.5 μg mL − 1 with excellent linearity in terms of the correlation coefficient value of 0.999. Most of the common metal ions generally found associated with aluminum(III) do not interfere. The repeatability of the method was checked by finding the relative standard deviation. The developed method has been successfully employed for the determination of aluminum(III) environmental matrices like medicinal and leafy samples, alloys, and synthetic mixtures.

N-Ethyl-3-cabazolecarboxaldehydethiosemicarbazone (ECCT) is proposed as a new, sensitive and selective complexing reagent for the separation and extractive spectrophotometric determination of palladium(II) at pH: 4.0 to form a yellowish orange colored 1:1 chelate complex, which is very well extracted in to n-butanol. The absorbance was measured at a maximum wavelength, 410 nm. This method obeys Beer’s law in the concentration range 0.0–6.6 μg mL−1 and the correlation coefficient of Pd(II)-ECCT complex is 0.998, which indicates an excellent linearity between the two variables with good molar absorptivity and Sandell’s sensitivity, 1.647 × 104 l mol−1cm−1, 6.49 × 10−3 μg cm−2, respectively. The instability constant of complex calculated from Edmond’s method, 2.724 × 10−5 was in good agreement with the value calculated from Asmus’ method 2.624 × 10−5, at room temperature. The precision and accuracy of the method is checked with calculation of relative standard deviation (n = 5), 0.839. Edmond’s method was observed to be a more selective method in the presence of EDTA, oxalate and phosphate ions. The method was successfully applied for the determination of Pd(II) in water samples, synthetic mixtures and hydrogenation catalysts, employing an atomic absorption spectrometer for comparing these results.

N-ethyl-3-carbazolecarboxaldehyde-3-thio- semicarbazone (ECCT) as an new analytical reagent used for the development of a highly sensitive extractive spectrophotometric method for the determination of copper(II). The ECCT forms a greenish-yellow colored 1:1 (M:L) complex with copper(II) at pH 3.0, which is well extracted into n-butanol and shows maximum absorbance at 380nm. The color of the complex is stable for more than forty eight hours. The system obey Beer's law in the range 0.4–3.6 with 2.243 × 104lmol−1cm−1, 2.83 × 10-3μgcm−2 molar absorptivity and Sandell's sensitivity respectively. The regression coefficient is 0.412 with 0.99 correlation coefficient. The precision and accuracy of the method was checked by finding the relative standard deviation (0.422%). This developed method has been successfully employed for the determination of copper(II) in environmental and pharmaceutical samples. The method is evaluated by analyzing samples from the bureau of analyzed samples (BCS 233, 266, 216/1, 207 and 179) and by inter comparison of experimental values using AAS.

N-ethyl-3-carbazolecarboxaldehyde-3-thiosemicarbazone (ECCT) is proposed as a new sensitive reagent for the extractive spectrophotometric determination of zinc(II). The ECCT forms yellow colored species of zinc(II) at pH range 3.0–5.5 and the complex was extracted into benzene. The Zn(II)–ECCT complex shows maximum absorbance at 420nm with molar absorptivity and Sandell’s sensitivity being 1.55×104litmol−1cm−1 and 4.212×10−3μgcm−2, respectively. The system obeys Beer’s law in the range of 0.4–6.0mg/l, with an excellent linearity in terms of correlation coefficient value of 0.999. Most of the common metal ions generally found associated with zinc do not interfere. The repeatability of the method was checked by finding relative standard deviation (RSD). The developed method has been successfully employed for the determination of zinc(II) in foods. Various certified reference materials (NIST 1573, NBS 1572 and NIST SRM 8435) have been tested for the determination of zinc for the purpose of validation of the present method.