Indian Journal of Chemistry 

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

Total visitors:1,431 since 13-09-05

VOLUME 44A

NUMBER 8

AUGUST 2005

 

Papers

 

1545

 

Simplified molecular input line entry system (SMILES) as an alternative for constructing quantitative structure-property relationships (QSPR)

 

 

Andrey A Toropov, Alla P Toropova,
Dilya V Mukhamedzhanova & Ivan Gutman*

 

 

 

Flexible descriptors calculated with correlation weights of fragments in the SMILES notation of molecular systems have been used as a tool for modeling normal boiling points of acyclic carbonyl compounds. Four variants of the optimization of correlation weights of SMILES fragments   have been examined.

 

 

1553

 

Mathematical representation of the density of liquid mixtures at various temperatures using Jouyban-Acree model

 

 

 

A Jouyban*, A Fathi-Azarbayjani,
M Khoubnasabjafari & W E Acree Jr

 

 

 

Applicability of a quantitative relationship of density with mixture composition and temperature of liquid mixtures is shown using 98 density data at various temperatures. An equation for correlating the density of binary liquid mixtures with mixture composition and temperature is proposed as:

 

 

1561

 

Synthesis and structure of a dinuclear nickel(II) complex with an unusual type of double [NAr2] bridges

 

 

 

 

 

 

 

 

Srijit Das, Shie-Ming Peng, Gene-Hsiang Lee & Sreebrata Goswami*

 

 

 

 


 

1565

 

Synthesis, structure and properties of [Co(L)(NO3)]ClO4.2H2O  (L = tetradentate Schiff bases): Example of chelating nitrate

 

Habibar Chowdhury, Sk Hafijur Rahaman, Rajarshi Ghosh, Tian-Huey Lu &
Barindra Kumar Ghosh*

 

 

 

Synthesis and characterization of three mononuclear cobalt(II) complexes of the type [Co(L)(NO3)]ClO4.2H2O
[L= N,N
˘-(bis(pyridin-2-yl)alkylidene)butane-1,4-diamine]  are described. These complexes show nitrate binding in (O,O) chelating fashion. In [Co(bpfd)(NO3)]ClO4.2H2O, the mononuclear units are engaged in intermolecular C-H…O and O-H…O hydrogen bonding leading to a 2D sheet.

 

 

1571

 

Synthesis and characterization of some cationic ruthenium(II) complexes based on polypyridyl ligand

 

 

 

 

 

 

 

 

 

 

Sanjeev Sharma, Manoj Trivedi &
Daya Shankar Pandey*

 

 

 

Reaction of the precursor [Ru(η5-arene)(EPh3)2Cl]  with
2,3-bis(2-pyridyl)pyrazine in 1:1 molar ratio in methanol affords new cationic complexes in excellent yield.

 

 

1576

 

Magnetic and spectroscopic characterization of copper(II) chlorobenzoate adducts with substituted piperidines

 

 

B S Manhas, S B Kalia*, A K Sardana &
G Kaushal

 

 

 

 

 

1582

 

Effect of temperature on the partial molar volumes of some bivalent transition metal nitrates and magnesium nitrate in DMF + water mixtures

 

 

 

 

M L Parmar* & D S Banyal

 

 

 

Partial molar volumes of some bivalent transition metal nitrates have been determined in their aqueous solutions and aqueous mixtures with DMF from solution density measurements at various temperatures and electrolyte concentrations.  All the electrolytes have been found to act as structure breakers in aqueous as well as in aqueous DMF mixtures.

 

 

1589

 

Volumetric studies of l-valine and l-leucine in aqueous solutions of NaBr at 298.15 K

 

 

 

 

 

Amalendu Pal* & Suresh Kumar

 

 

 

Densities of the amino acids, l-valine and l-leucine, in aqueous solutions of sodium bromide have been measured at 298.15 K and apparent molar volumes and partial molar volumes of the amino acids at infinite dilution have been evaluated. The trends of transfer volumes have been interpreted in terms of solute-cosolute interactions on the basis of a cosphere overlap model. Pair and triplet interaction coefficients have also been calculated from the transfer parameters.

 

Notes


 

1594

 

The effect of 18–crown-6 on the solubility and thermodynamic parameters of Li2CO3, Na2CO3, NaCl, CH3COONa and KCl in methanol and ethanol

 

 

 

 

 

F I El-Dossoki

 

 

 

The effect of different concentrations of a cyclic polyether 18 – crown – 6 (18C6) on the solvation parameters of some alkali metal salts has been studied. The molal solubilities of Li2CO3, Na2CO3, NaCl, CH3COONa and KCl have been determined in the absence and in presence of different concentrations of 18C6 in methanol and ethanol at 20, 25, 30 and 35oC. The solvation thermodynamic parameters (the free energy, the enthalpy and the entropy) have been calculated. Also, the effects of different concentrations of 18C6, temperature, anion, ionic radius and solvent on the parameters have been discussed.

 

 

1597

 

Redox linked protonation/deprotonation on the carboxylate of [Fe4S4(SCH2CH2COO-)4]6- in aqueous micellar solutions

 

 

 

 

 

 

Raben Ch. Roy & Diganta Kumar Das*

 

 

 

 

 

 

1602

 

Speciation of dimethyltin(IV) and trimethyltin(IV) cations with some biologically important ligands in aqueous medium: A potentiometric investigation

 

 

 

 

 

 

 

M Nath*, R Jairath, G N Mukherjee & A Das

 

 

 

The coordination of Me2Sn(IV)2+ and Me3Sn(IV)+ to uracil, thymine, 5-fluorouracil, thymidine and l-ascorbic acid in aqueous solution has been investigated by potentiometric titration. The ligands with potential oxygen donor groups such as thymidine and l-ascorbic acid interact more strongly with Me2Sn(IV)2+ and Me3Sn(IV)+ as compared to those with potential nitrogen donor groups, viz., uracil, thymine and 5-fluorouracil.

 

1608

 

Thermodynamic stabilities and thermodynamic parameters of metal-substituted thiosemicarbazide complexes

 

 

 

 

 

 

Shailey Gupta & M N Ansari*

 

 

 

The stability constants of complexes of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) with 2-amino-4-benzamido-thiosemicarbazide have been found to be proportional to their ionic strengths and inversely proportional to the temperature. Negative values of DG° and DH° show spontaneous and exothermic reactions between the metals and the ligand. Positive DS° values have been observed in all the cases except in the case of Fe(III) complex.

 

 

1610

 

Electrochemical studies on polystyrene based membrane of zirconium(IV) antimonoarsenate

 

 

 

 

 

 

 

Susheel K Mittal* & Harish Kumar Sharma

 

 

 

Electrochemical studies have been carried out on heterogeneous ion exchange membranes of zirconium(IV) antimonoarsenate using polystyrene as a binder. Transport number, permselectivity and fixed charge density of the exchanger membrane and halide salts of some alkali and alkaline earth metals as electrolytes have been determined. The membrane potential data conform to the Kobatake theoretical treatment of irreversible processes.

 


 

1615

 

Biosorption of europium radionuclide by calcium alginate beads

 

 

 

 

Dalia Nayak

 

 

 

Adsorption behavior of 152Eu with calcium alginate beads has been studied. High removal is achieved in a wide pH range of 2-8. Nearly 98% europium removal has been attained at pH 3. Recovery of europium radionuclide has also been achieved using HCl. It has been observed that 95% of adsorbed 152Eu is removed with 1 M HCl.

 

 

1619

 

Determination of mercury in geological samples by cold vapour atomic absorption spectrometric technique

 

 

 

 

 

Ramavati Mathur*, V Balaram & S Suresh Babu

 

 

 

A method for determination of total mercury in geological samples using acid digestion and subsequent measurement by cold vapor atomic absorption spectrometric technique is described. The detection limit of mercury is found to be
5 ng when 1 ml of 1% sample solution is utilized. Enhanced extraction is observed in several cases while using closed vessel digestion.

 

 

1625

 

Extraction spectrophotometric determination of micro amounts of palladium(II) in catalysts

 

 

 

 

 

S H Gaikwad, T N Lokhande & M A Anuse*

 

 

 

A new reagent, 4-(2´-furalideneimino)-3-methyl-5-mercapto-1,2,4-triazole has been synthesized and used as a chromogenic reagent for palladium(II). Palladium(II) has been extracted as a yellow complex (lmax 410 nm) from an aqueous solution at pH 5.4 with FIMMT in n-butanol. The molar extinction coefficient and Sandell’s sensitivity are 1.4´103 L mol-1 cm-1 and 0.073 µg cm-2, respectively.

 

 

Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1545-1552

 

Simplified molecular input line entry system (SMILES) as an alternative for constructing quantitative structure-property relationships(QSPR)

Andrey A Toropov, Alla P Toropova, Dilya V Mukhamedzhanova & Ivan Gutman*

Received 7 April 2005; revised 7 June 2005

Flexible descriptors calculated with correlation weights of fragments in the SMILES notation of molecular systems have been used as a tool for modeling normal boiling points of acyclic carbonyl compounds. Four variants of the Optimization of Correlation Weights of SMILES Fragments (OCWSF) have been examined. The difference between them is in the number of symbols in the SMILES fragments. Thus, fragments involving one-, two-, three-, and four-symbols have been examined.  Correlation weights for three calculable features of SMILES are used in the OCWSF scheme: number of oxygen atoms (NO), number of double bonds (NDB), and (NO - NDB +10). In order to take into account the hydrogen bond interactions, correlation weights of these three features have been included in the OCWSF scheme. The best OCWSF model is based on three-symbol fragments together with the mentioned three features of the SMILES notation. Its statistical characteristics are: n=100, r2=0.9795, s=5.35 °C, F=4673 (training set); n=100, r2=0.9764, s=5.38 °C, F=4055 (test set).

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1553-1560


Mathematical representation of the density of liquid mixtures at various temperatures using Jouyban-Acree model

A Jouyban* , A Fathi-Azarbayjani, M Khoubnasabjafari & W E Acree Jr

Received 31 January 2005; revised 23 May 2005

Applicability of a quantitative relationship of density with mixture composition and temperature of liquid mixtures is shown using 98 density data at various temperatures, with an overall average percentage deviation (OAPD) as accuracy criterion. The OAPD of the Jouyban-Acree model is also compared with those of three previously published equations and the OAPD (±SD) of the proposed and previous equations are 0.05 ± 0.06, 0.12 ± 0.15, 0.16 ± 0.22 and 0.15 ± 0.22, respectively. The differences between OAPD of the Jouyban-Acree model with those of previous models are statistically significant (p<0.0005). The prediction capability of the proposed model is also compared with that of the best reported correlative equation and the proposed model provides more accurate predictions.

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1561-1564


Synthesis and structure of a dinuclear nickel(II) complex with an unusual type of double [NAr2] bridges

Srijit Das, Shie-Ming Peng, Gene-Hsiang Lee & Sreebrata Goswami*

Received 22 March 2005; revised 20 May 2005

The reaction of equimolar quantities of Ni(ClO4)2∙6H2O, NaN3 and a deprotonated tetradentate bridging N-donor ligand, [L2]-, HL2=2-[2-(pyridylamino)phenylazo]pyridine, produces a novel di-metallic Ni2-complex having double [NAr2] bridges. The complex has been isolated and suitable X-ray quality crystals grown through slow evaporation of the concentrated acetonitrile solution of the compound. The complex has been characterized fully using its physicochemical properties as well as single crystal X-ray data analysis. Its structure reveals that the two deprotonated secondary amine nitrogens, viz. N(4) and N(9) of two [L2]- bind two Ni(II) centers simultaneously forming planar Ni2N2 arrangement. The complex is paramagnetic and its solution exhibits blue colour, which shows charge-transfer transitions near 600 nm.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1565-1570


Synthesis, structure and properties of [Co(L)(NO3)]ClO4.2H2O (L = tetradentate Schiff bases): Example of chelating nitrate

Habibar Chowdhury, Sk Hafijur Rahaman, Rajarshi Ghosh, Tian-Huey Lu & Barindra Kumar Ghosh*

Received 6 April 2005; accepted 10 June 2005

The synthesis and characterization of three mononuclear cobalt(II) complexes of the type [Co(L)(NO3)]ClO4.2H2O [L = N,N˘-(bis(pyridin-2-yl)formylidene)butane-1,4-diamine (bpfd), 1; N,N˘-(bis(pyridin-2-yl)methylidene)butane-1, 4-diamine (bpmd), 2; and N,N˘-(bis(pyridin-2-yl)benzylidene)butane-1,4-diamine (bpbd), 3] are described here. In IR, the presence of n(NO3) band at ~1380 cm-1 with distinct splittings is strongly suggestive of coordination of nitrate instead of its simple counter anionic view. X-ray diffraction studies of [Co(bpfd)(NO3)]ClO4.2H2O (1), has been made for the exact knowledge of its coordination sphere. Structural analysis reveals cobalt(II) centre in a distorted octahedral environment with a CoN4O2 chromophore ligated by four N atoms of the tetradentate Schiff base along with two O atoms of nitrate in a chelating fashion. The tetradentate chelator is folded in the butylenic part. The mononuclear units in 1 are engaged in intermolecular C-H…O and O-H…O hydrogen bondings leading to a 2D sheet. Electrochemical electron transfer studies in MeCN solutions show an oxidative response presumably due to cobalt(III)-cobalt(II) couple. All the complexes display intraligand 1(p-p*) fluorescence and intraligand 3(p-p*) phosphorescence in glassy solutions (MeOH at 77 K).

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1571-1575


Synthesis and characterization of some cationic ruthenium(II) complexes based on polypyridyl ligand

Sanjeev Sharma, Manoj Trivedi & Daya Shankar Pandey*

Received 21 February 2005; accepted 14 June 2005

The cationic mononuclear complexes [Ru(η5-arene)(k2-dpp)(EPh3)]+ 5-arene = C5H5 (1), C5Me5 (2)C9H7(3);E=P(1a, 2, 3), As (1b); dpp = 2,3-bis(2-pyridyl) pyrazine) resulting from the reactions of [Ru(η5-arene)(EPh3)2Cl] with dpp in equimolar ratio in methanol under refluxing conditions, containing both group 15 donor and a planar polypyridyl ligand are reported here. These complexes have been isolated as their hexafluorophosphate salts and fully characterized by elemental analyses and spectral techniques, viz. IR, 1H and 31P NMR, FAB-MS and electronic spectral studies.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1576-1581


Magnetic and spectroscopic characterization of copper(II) chlorobenzoate adducts with substituted piperidines

B S Manhas, S B Kalia*, A K Sardana & G Kaushal

Received 17 January 2005; revised 25 May 2005

Copper(II) chlorobenzoates react with substituted piperidines in an organic medium to give solid complexes having general formula [Cu(OOCR)2(L)] (R = 2-,3- or 4-ClC6H4 and L = 1-methyl, 1-ethyl and 2,6-dimethylpiperidine). All the complexes with copper(II) chlorobenzoates are of 1:1 stoichiometry irrespective of the amount of the ligand added and have been shown by physico-chemical methods to be binuclear, containing bidentate bridging carboxylate group except [Cu(OOCC6H4Cl-4)2(2,6-Me2Pipd)] for which polymeric square pyramidal structure has been proposed. All the complexes show antiferromagnetic behaviour with the exception of [Cu(OOCC6H4Cl-4)2(2,6-Me2Pipd)] which is paramagnetic. The spin exchange parameter, -2J, for two of the complexes has been evaluated from magnetic susceptibility measurements at different temperatures, which corresponds to axial binuclear copper(II) complexes with S = 1.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1582-1588

 

Effect of temperature on the partial molar volumes of some bivalent transition metal nitrates and magnesium nitrate in DMF + water mixtures

M L Parmar* & D S Banyal

Received 23 December 2004; revised 14 June 2005

Partial molar volumes of some bivalent transition metal nitrates viz; manganese nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, and magnesium nitrate have been determined in aqueous and aqueous mixtures of dimethylformamide (5, 10, 15, 20 and 25% by weight of dimethylformamide) from solution density measurements at various temperatures and electrolyte concentrations.  The data were evaluated by using Masson equation and the obtained parameters interpreted in terms of ion-solvent and ion-ion interactions.  The partial molar volumes vary with temperature as a power series of temperature.  Structure making/breaking capacities of the electrolytes have been inferred from the sign of [2fv0/T2]p, i.e. second derivative of partial molar volume with respect to temperature at constant pressure.  All the electrolytes have been found to act as structure breakers in aqueous as well as in aqueous dimethyl formamide mixtures.

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1589-1593


Volumetric studies of l-valine and l-leucine in aqueous solutions of NaBr at 298.15 K

Amalendu Pal* & Suresh Kumar

Received 4 November 2004; revised 23 May 2005

Densities (r) of the amino acids, l-valine and l-leucine, in aqueous solutions of sodium bromide (0.05-1.0 mol kg-1) have been measured at 298.15 K. From these densities, apparent molar volumes (Vf) and partial molar volumes of the amino acids (Vf0) at infinite dilution have been evaluated. The data have been combined with the known values of Vf0 of glycine, and l-alanine in aqueous NaBr solutions at 298.15 K in order to determine the group contributions. The trends of transfer volumes (DVf0) have been interpreted in terms of solute-cosolute interactions on the basis of a cosphere overlap model. Pair and triplet interaction coefficients have also been calculated from transfer parameters.

Indian Journal of Chemistry

Vol. 44A, August 2005, pp.1594-1596


The effect of 18-crown-6 on the solubility and thermodynamic parameters of Li2CO3, Na2CO3, NaCl, CH3COONa and KCl in methanol and ethanol

F l El-Dossoki

Received 19 September 2004; revised 8 June 2005

The effect of different concentrations of a cyclic polyether 18-crown-6 (18C6) on the solvation parameters of some alkali metal salts has been studied . The molal solubilities of Li2CO3, Na2CO3, NaCl, CH3COONa and KCl have been determined experimentlly (using volumetric and precipitation titrations) in the absence and in presence of different concentrations of 18C6 in methanol and ethanol at 20, 25, 30 and 35oC. From the experimental results , the solvation thermodynamic parameters (the free energy, the enthalpy and the entropy) have been calculated and discussed. Also the effects of different concentrations of 18C6, temperature, anion, ionic radius and solvent on the parameters have been discussed.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1597-1601


 

Redox linked protonation/deprotonation on the carboxylate of [Fe4S4(SCH2CH2COO-)4]6- in aqueous micellar solutions

Raben Ch. Roy & Diganta Kumar Das*

Received 9 February 2005; revised 6 June 2005

[Fe4S4(SCH2CH2COO-)4]6-, which acts as active center analogue of ferredoxin, demonstrates a proton coupled electron transfer phenomenon  with  pKaOx at 3.0, 2.5, and 3.2 and pKaRed at 4.7, 4.3, and 4.8, in 3% (w/v) aqueous SDS, TX-100 and CTAB micelles. When the operating pH is between pKaOx and pKaRed, the observed redox Bohr effect exhibits a 60 to 70 mV per pH unit slope indicating one proton per electron coupled event. These low pKa values arise because of the protonation/deprotonation of one of the four carboxylates. Also, protonation of the carboxylate leads to 120-140 mV positive shift in the mid-point potential. Formation of H bonding between the carboxylate and the neighbouring protonated core S is proposed as reason for the very low pKa.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1602-1607


Speciation of dimethyltin(IV) and trimethyltin(IV) cations with some biologically important ligands in aqueous medium: A potentiometric investigation

M Nath*, R Jairath, G N Mukherjee & A Das

Received 8 September 2004; revised 16 June 2005

The coordination of Me2Sn(IV)2+ and Me3Sn(IV)+ to uracil, thymine, 5-fluorouracil, thymidine and L-ascorbic acid in aqueous solution has been investigated by means of potentiometric titration. The concentration distribution of the various complex species in solution has been evaluated as a function of pH. It has been found that the ligands (L) with potential oxygen donor groups such as thymidine and L-ascorbic acid interact more strongly with Me2Sn(IV)2+ and Me3Sn(IV)+ as compared to those with potential nitrogen donor groups, viz. uracil, thymine and 5-fluorouracil at pH 7. The complexes are water soluble in the pH range 2-11. Thymidine forms ~28% of Me2SnL and ~60% of Me3SnLH, whereas, L-ascorbic acid forms ~60% Me2SnL(OH) and ~60% Me3SnL with Me2Sn(IV)2+ and Me3Sn(IV)+, respectively, at physiological pH. On the other hand, the nucleic acid bases, viz., uracil, thymine and 5-fluorouracil have been found to form only small amount of Me2SnL(OH) (~10-20%) and Me3SnL (~10-15%) under similar conditions. Significant amounts of hydroxo species, viz. Me3SnOH and Me2Sn(OH)2, are also formed at pH 7.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1608-1609


Thermodynamic stabilities and thermodynamic parameters of metal-substituted thiosemicarbazide complexes

Shailey Gupta & M N Ansari*

Received 19 July 2004; revised 20 May 2005

The stability constants of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes with 2-amino-4-benzamidothiosemicarbazide have been found to be proportional to their ionic strengths and inversely proportional to the temperature. Negative values of ΔG° and ΔH° show spontaneous and exothermic reactions respectively between the metals and the ligand. Positive ΔS° values have been observed in all the cases except in case of Fe(III).

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1610-1614


Electrochemical studies on polystyrene based membrane of zirconium(IV) antimonoarsenate

Susheel K Mittal* & Harish Kumar Sharma

Received 4 November 2004; revised 24 May 2005

Electrochemical studies have been carried out on heterogeneous ion-exchange membranes of zirconium(IV) antimonoarsenate using polystyrene as a binder. Electrical characteristics like transport number, permselectivity and fixed charge density of the exchanger membrane and halide salts of some alkali and alkaline earth metals as electrolytes have been determined. The membrane potential data conforms to the Kobatake theoretical treatment of irreversible processes. The effect of electrolyte concentration on transport numbers and permselectivity has also been studied. Results indicate that the membrane is permselective for counterions and possesses weak electrical character.

Indian Journal of Chemistry

Vol. 44A, August. 2005, pp. 1615-1618


Biosorption of europium radionuclide by calcium alginate beads

Dalia Nayak

Received 21 June 2004; revised 8 June 2005

Studies on adsorption behaviour of 152Eu have been carried out with calcium alginate beads. High removal is achieved in a wide pH range 2-8. Nearly 98% europium removal has been attained at pH 3. Recovery of europium radionuclide has also been achieved using HCl. It has been observed that 1 M HCl could remove 95% of adsorbed 152Eu.

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1619-1624


Determination of mercury in geological samples by cold vapour atomic absorption spectrometric technique

Ramavati Mathur*, V Balaram & S Suresh Babu

Received 13 April 2004; revised 8 June 2005

A method for determination of total mercury in geological samples using acid digestion and subsequent measurement by cold vapour atomic absorption spectrometric technique is described. Sample digestion has been carried out using a combination of hydrochloric and nitric acids followed by reduction of mercury (II) in the extract to its elemental form by stannous chloride. The absorption signal at 253.7 nm has been monitored with a mercury analyzer. The method is simple, cost effective and gives reliable results as indicated by the data obtained on a few international geochemical reference samples, analyzed in this study. Precision of the measurements is within 5% RSD for closed vessel digestion. The detection limit of mercury is found to be 5 ng when 1 ml of 1% sample solution is utilized. Comparison of data obtained for the same set of standards using both open vessel and closed Savillex pressure decomposition vessel digestions demonstrates enhanced extraction in several cases while using closed vessel digestion. Results indicate that the method can be applied for determination of low levels of mercury in a variety of geological samples for exploration studies.

 

Indian Journal of Chemistry

Vol. 44A, August 2005, pp. 1625-1630

Extraction spectrophotometric determination of micro amounts of palladium(II) in catalysts

S H Gaikwad, T N Lokhande & M A Anuse*

Received 5 December 2003; revised 24 March 2005

A new reagent, 4-(2´-furalideneimino)-3-methyl-5-mercapto-1,2,4-triazole, has been synthesized and used as a chromogenic reagent for palladium(II). Palladium(II) has been extracted as a yellow complex (lmax 410 nm) from an aqueous solution at pH 5.4 with FIMMT in n-butanol. The molar extinction coefficient and Sandell’s sensitivity are 1.4 ´103 L mol-1 cm-1 and 0.073 µg cm-2, respectively. The effects of pH, reagent concentration, solvent, shaking time and stability of the complex have been studied. The complex system confirms to Beer’s law over the range 5-50 ppm of palladium(II) with optimum range 17-50 ppm of the metal as evaluated from Ringbom’s plot. The tolerance limit for many metal ions has been determined. The method has been applied successfully for the determination of palladium(II) in synthetic mixtures corresponding to alloys and palladium(II) in various hydrogenation catalysts.