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Indian Journal of Chemistry

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

 

VOLUME 44A

NUMBER 3

March 2005

 

CONTENTS

 

Rapid Communication

 

447

 

Synthesis and photoluminescent characteristics of yellow ZnS:Cu,Cl phosphor

 

 

 

 

Gaytri Sharma, Anita Sharma, Devender Singh, Ishwar Singh, Young-Woo Rhee & Sang-Do Han*

 

 

 

A yellow ZnS:Cu,Cl phosphor has been prepared using two firing steps. The phosphor produced after the first firing shows photoluminescence emitting light at 540 nm, but does not show any electroluminescence. Second step firing at 750C in the presence of CuSO4 and MgCl2, not only increases the photoluminescent brightness but also produces electroluminescence. The morphology of the ZnS matrix changes from wurtzite to sphalerite after second firing.

Papers

 

451

 

Spectroscopic studies on the interaction between methyl glyoxal and ascorbic acid: Some experimental and theoretical aspects

 

 

 

 

  

 

 

 

 

D Banerjee, A Koll, A Filarowski, S P Bhattacharyya & S Mukherjee*

 

 

 

456

 

Carbon (CDX-975) based Pt electrodes for direct methanol fuel cell (DMFC) applications

 

 

  

V Chidambaram*, B Srinivas & B Viswanathan

 

 

 

The use of CDX 975 for support for electrode applications in methanol fuel cell is described. Study on the effect of the extent of Pt loading and the performance of various electrodes in methanol oxidation reactions shows that 10% Pt is the optimal loading for electrode applications.

 

 

463

 

Horseradish peroxidase catalyzed and electrochemical oxidations of 2-thiouracil
A comparison

 

  

Rajendra N Goyal*, Sham M Sondhi, Anand M Lahoti & Adil A Abdulla

 

 

 

Horseradish peroxidase (type VIII) catalyzed and electrochemical oxidations of 2-thiouracil have been studied in phosphate buffer of pH 7.20 (=1.0 M) at an ambient temperature of 252C. Study shows that redox mechanisms proposed for oxidation of 2-thiouracil by enzymic and electrochemical methods are similar.

 

 

469

 

Volumetric and viscometric studies of L-glycine in binary aqueous solutions of sucrose at different temperatures

 

 

  

 

Amalendu Pal* & Suresh Kumar

 

 

 

Densities and viscosities of L-glycine have been measured at 288.15, 298.15 and 308.15 K in aqueous sucrose solutions ranging from 5 25 mass % of sucrose. Apparent molar volumes, limiting partial molar volume and relative viscosity have been evaluated from these data. The results have been discussed in terms of solute-solute and solute-solvent interactions and the structural changes of the solutes in solutions.

 

476

 

Mechanistic study of Pd(II) catalysed oxidation of maleic and crotonic acids by N-chlorosuccinimide in perchloric acid medium

 

 

 

 

 

 

 

 

 

 

 

Ashish, Chhaya Singh, Ashok Kumar Singh & Bharat Singh*

 

 

 

                                   K1

[PdCl4]2- + NCS                    [PdCl4.NCS]2-               (I)

         C1                                     C2

 

[PdCl4.NCS]2-      [PdCl3.NCS] +Cl           (II)

       C2                                 C3

[PdCl3.NCS] + S  [PdCl2(H2O)2]+2Cl
                                 + NHS + Intermediate(X)  (III)

                          (IV)

++          (V)

 

 

483

 

Substitution on [(H2O)(tap)2RuORu-(tap)2(H2O)]2+ ion with inosine at physiological pH in aqueous medium

 

 

 

 

  

Hriday Chattopadhyay & Alak Kumar Ghosh*

 

 

 

The interaction of inosine with the title complex has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand], pH and temperature at constant ionic strength. At physiological pH (7.4), the interaction with inosine shows two distinct consecutive steps, both of which are [ligand] dependent. An associative interchange mechanism is proposed for the reaction, supporting the spontaneous formation of an outer sphere association complex.

 

490

 

Triosmium clusters containing bridging dppm and PhSe ligands: X-ray crystal structure of
[(m-H)Os3(CO)8(m-SePh)(m-dppm)]

 

 

 

 

 

  

Noorjahan Begum, Md. Manjur Hassan & Shariff E Kabir*

 

 

 

497

 

Solvent extraction, separation and recovery of lanthanum(III) and cerium(IV) from monazite sand by N-phenylbenzo-18-crown-6 hydroxamic acid

 

 

 

 

 

 

 

Y K Agrawal*, S B Vora & G Shah

 

 

 

A new N-phenylbenzo-18-crown-6-hydroxamic acid is reported for the separation of lanthanum(III) and cerium(IV) from monazite. La(III) gives a colourless complex with molar absorptivity of 9.0 x 103 L mol-1cm-1 at 385 nm. Ce(IV) forms a red colour complex with lmax 450 nm and molar absorptivity 6.5 x 103 L mol-1 cm-1. The proposed method of preconcentration and analysis of La(III) and Ce(IV) is not adversely affected by highly ionic media, rendering the method suitable for their trace determination in sea water.

Notes

 

504

 

Synthesis, spectral and kinetic studies of copper(II) thiocarboxylates as molecular precursor for metal sulfide

 

 

 

 

Tarkeshwar Gupta & B P Baranwal*

 

 

 

A series of binary and ternary copper(II) complexes of thiocarboxylic acids and straight chain fatty
acids with general formula Cu(SOCR)2(EtOH) and Cu(SOCR)(OOCR)(EtOH) [where R = CH3 or C6H5 and R = C7 H15, C11H23 or C13H27] have been synthesized and characterized. The binary copper(II) complexes have the potential to act as precursors for metal sulfido species.

 

511

 

Molecular interactions in binary mixtures of anisole with benzyl chloride, chlorobenzene and nitrobenzene at 303.15 K: An ultrasonic, volumetric, viscometric and refractive index study

 

 A Ali*, A K Nain, D Chand & B Lal

 

 

 

The variations of excess properties like excess molar volume, excess free energy of activation, etc. with composition suggest that the strength of interactions in anisole binary mixtures follow the order: benzyl chloride > nitrobenzene > chlorobenzene.

 

 

516

 

Ruthenium(I) complexes with 4-ethoxy-phenyl tellurol: X-ray crystal structure of complex [Ru2(CO)4(m-TeC6H4OCH2CH3-4)2 (m-dppm)] (dppm=Ph2PCH2PPh2)

 

 

 

  

 

Noorjahan Begum, Md Iqbal Hyder, Shahidul Islam, Shariff E Kabir, Kalipada Kundu* & K M Abdul Malik*

 

 

 

521

 

Ruthenium complexes containing bridging dppm and benzene-1,2-dithiolato ligands: X-ray crystal structure of [Ru2(CO)4{m-S(C6H4)S}(m-dppm)]

 

 

  

 

 

 

Noorjahan Begum, Md. Iqbal Hyder, Shariff E Kabir* & Kalipada Kundu

 

 

 

526

 

Kinetic determination of traces of Al(III) ion by its catalytic effect on oxidation of 4-hydroxycoumarin by potassium permanganate

 

 

 

 

R P Igov, R M Simonović, T G Pecev* & B B Veselinović

 

 

 

Oxidation of 4-hydroxycoumarin by potassium permanganate in acid media of acetate buffer is catalyzed by Al(III) ions. Under the optimum conditions, Al(III) has been determined at 525 nm in the range 50-1000 ng/ml with probable relative error of 15.6 - 5.1 % and detection limit of 20 ng/ml. Appropriate kinetic equations for both catalytic and noncatalytic processes have been derived and the mechanism of catalytic effect of Al(III) investigated.

 

 

529

 

Pulse polarographic determination of organoisothiocyanates and a method for the analysis of Ditrapex

 

 

 

 

B C Verma*, Chetan Chauhan, Lata Thakur & D K Sharma

 

 

 

In acetonitrile medium, n-butylamine transforms organoisothiocyanates quantitatively into the corresponding thiourea derivatives which show well-defined diffusion controlled anodic waves in the presence of aqueous sulphuric acid and potassium perchlorate. The method has been successfully adapted for the analysis of Ditrapex, an insecticide formulation containing methyl isothiocyanate.

 

 

531

 

Separation of gold and silver using a chelating
resin-thiosemicarbazide incorporated Amberlite IRC-50

 

 

 

Kamalika Roy & S Basu*

 

 

 

A thiosemicarbazide group incorporated into a weakly acidic resin, Amberlite IRC-50, can selectively entrap gold and silver. The newly formed resin has a satisfactory exchange capacity for Au(III) and Ag(I) and can be utilized for the separation of these noble metals from different complex matrices.

 

 

Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 447-500

 

Synthesis and photoluminescent characteristics of yellow ZnS:Cu,Cl phosphor

 Gaytri Sharma, Anita Sharma, Devender Singh, Ishwar Singh, Young-Woo Rhee & Sang-Do Han*

 

A yellow ZnS:Cu,Cl phosphor has been prepared using two-firing steps. Firing ZnS in the presence of activator CuSO4 and the flux BaCl2, MgCl2 and NaCl in the mole percentage ratio of 13.8: 39.9:46.2 at 1150C for 5 h in N2 atmosphere produces a wurtzite structure of the ZnS matrix with the particle size above 25 m. The phosphor shows photoluminescence emitting light at 540 nm, but does not show any electroluminescence property at this stage. Second step firing at 750C in the presence of CuSO4 and MgCl2, not only increases the photoluminescent brightness but also produces electroluminescence. The morphology of the ZnS matrix changes from wurtzite to sphalerite after second firing. Sphalerite structure for ZnS:Cu,Cl phosphor is essential for producing electroluminescence.

IPC Code: Int.Cl.7 C09K11/54

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 451-455

 

Spectroscopic studies on the interaction between methyl glyoxal and ascorbic acid: Some experimental and theoretical aspects

D Banerjee, A Koll, A Filarowski, S P Bhattacharyya & S Mukherjee*

 

The interaction between methyl glyoxal (MG) and ascorbic acid (AA) has been studied both theoretically and experimentally using NMR and Raman spectroscopic techniques. A plausible explanation for the spectral changes has been suggested on the basis of hydrogen bonding interaction between the interacting species. The energetics of the interaction between MG and AA has been studied at the AM1 level of approximation. The HO distance in the -CH2OHO=C- fragment of the hydrogen bonded complex turns out to be quite small (2.22 ). Ab initio calculations with DFT B3LYP/6/31G(d,p) basis sets have been used to get confirmative evidences about the hydrogen bonded complex.

IPC Code: Int. Cl.7 G01J3/44; G01R33/20

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 456-462

 

Carbon (CDX-975) based Pt electrodes for direct methanol fuel cell applications

V Chidambaram*, B Srinivas & B Viswanathan

 

Normally, carbon materials, especially, Vulcan XC 72 are used as supports for Pt for the electrodes in fuel cells. The use of CDX 975 (a product of Columbian Chemical Company, Georgia) for support for electrode applications in methanol fuel cell is described here. The effect of the extent of Pt loading and the performance of various electrodes in methanol oxidation reactions has been studied. It is shown that 10% Pt is the optimal loading for electrode applications.

IPC Code: Int. Cl.7: C04B35/52; H01M8/00

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 463-468

 

Horseradish peroxidase catalyzed and electrochemical oxidations of 2-thiouracilA comparison

 Rajendra N Goyal*, Sham M Sondhi, Anand M Lahoti & Adil A Abdulla

 

Horseradish peroxidase (type VIII) catalyzed and electrochemical oxidations of 2-thiouracil have been studied in phosphate buffer of pH 7.20 (=1.0 M) at an ambient temperature of 252C. The peroxidase catalyzed oxidation has been initiated by using hydrogen peroxide and electrooxidation carried out at pyrolytic graphite electrode. The UV-absorbing intermediates generated in both the oxidations have been characterized by voltammetry, spectrophotometry and by kinetics of decay and are found identical. Products of enzymic and electrochemical oxidations have been characterized by using GC-MS stuides. A tentative redox scheme has been proposed for the enzymic oxidation of 2-thiouracil and compared with that of electrooxidation and has also been found similar. Thus, it has been concluded that oxidation of 2-thiouracil by enzymic and electrochemical methods are, in a chemical sense, identical.

IPC Code: Int.Cl.7 C25B3/02; C07B33/00

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 469-475

 

Volumetric and viscometric studies of glycine in binary aqueous solutions of sucrose at different temperatures

 Amalendu Pal* & Suresh Kumar

 

Densities and viscosities of glycine have been measured at 288.15, 298.15 and 308.15 K in aqueous sucrose solutions ranging from 5 to 25 mass % of sucrose. The viscosity data have been analyzed using the Jones-Dole equation. Apparent molar volumes, limiting partial molar volume and relative viscosity have been evaluated from the density and viscosity data. Transfer volumes and limiting partial molar expansibilities have also been calculated from the temperature dependence of limiting partial molar volumes. The results have been discussed in terms of solute-solute and solute-solvent interactions and the structural changes of the solutes in solutions.

IPC Code: Int.Cl.7 G01N

 

Indian Journal of Chemistry

Vol. 44, March 2005, pp. 476-482

 

Mechanistic study of Pd(II) catalysed oxidation of maleic and crotonic acids by N-chlorosuccinimide in perchloric acid medium

 Ashish, Chhaya Singh, Ashok Kumar Singh & Bharat Singh*

 

The kinetics of oxidation of maleic and crotonic acids by N-chlorosuccinimide (NCS) in perchloric acid are presented. Analysis of the results shows that the observed rates of oxidation indicate zero order in [substrate] and [H+]. First order dependence of the reactions on NCS at its lower concentrations tends to zero order in its higher concentration range. The reaction rate increases with increase in [Pd(II)] but the order in [Pd(II)] is less than unity. The initial addition of Cl and five fold excess of added succinimide (NHS) do not affect the rate significantly. Increase in ionic strength has negligible effect on the rate while increase in acetic acid content in reaction medium decreases the rate. Mechanistic steps are discussed on the basis of kinetic observations and products analysis.

IPC Code: C07B33/00

 

 

 

Indian Journal of Chemistry

Vol. 44, March 2005, pp. 483-489

 

 Substitution on [(H2O)(tap)2RuORu(tap)2(H2O)]2+ ion with inosine at physiological pH in aqueous medium

Hriday Chattopadhyay & Alak Kumar Ghosh*

 

The interaction of inosine with the title complex has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand], pH and temperature at constant ionic strength. At physiological pH (7.4) the interaction with inosine shows two distinct consecutive steps; both the processes are [ligand] dependent. An associative interchange mechanism is proposed; the activation parameters calculated from Eyring plots are: DH1 = 12.5 1.1 kJ mol-1, DS1 = -259 3 JK-1 mol-1, DH2 = 28.9 1.1 kJ mol-1 and DS2 = -230 3 JK-1 mol-1. From temperature dependence of the outer sphere association complex formation equilibrium constant, the thermodynamic parameters calculated are: DH1 = 12.1 1.0 kJ mol-1, DS1 = 100 3 J K-1 mol-1 and DH2 = 7.6 0.3 kJ mol-1, DS2 = 70 1 JK-1 mol-1, which gives a negative DG at all temperatures studied, supporting the spontaneous formation of an outer sphere association complex.

 

IPC Code: Int. Cl.7 C07F15/00

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 490-496 

Triosmium clusters containing bridging dppm and PhSe ligands: X-ray crystal structure of [(m-H)Os3(CO)8(m-SePh)(m-dppm)]

Noorjahan Begum, Md. Manjur Hassan & Shariff E Kabir*

 

Treatment of [(m-H)Os3(CO)8{Ph2PCH2P(Ph)C6H4}] 2 with phenylselenol at room temperature gives [(m-H)Os3(CO)8(m-SePh)(m-dppm)] 3 and [(m-H)Os3(CO)8(m-SePh)(h1-SePh){Ph2PCH2P(Ph)C6H4}] 4 in 49 and 6% yields, respectively. The reaction of [Os3(CO)10(m-dppm)] 1 with phenylselenol at 110C gives 3 in 27% yield. When irradiated (UV) under an atmosphere of CO, 3 eliminates benzene and is transformed to [Os3(CO)7(m3-CO)(m-Se)(m-dppm)] 5. Compound 3 reacts with excess CF3COOH to give the cationic hydrido derivative [(m-H)2Os3(CO)8(m-SePh)(μ-dppm)]+ 6, isolated as PF6 salts in good yield. All the compounds have been characterized by spectroscopic data, including an X-ray structure determination for 3. Compound 3 crystallizes in the triclinic space group P-1 with a=11.5354(2), b=12.6493(2), c=15.1523(2) , a=112.9239(6), b=91.4324 (7), g=106.4148(6), V=1902.90(5) 3 and Z=2. The compound consists of an isosceles triangle of osmium atoms, one edge of which is simultaneously bridged by a SePh group and a hydride ligand while one of the other edges is spanned by the dppm ligand.

IPC Code: Int. Cl.7 C07F15/00; G01N23/00; C07C391/02

 

 

 

Indian Journal of Chemistry

 Vol. 44A, March 2005, pp. 497-503

 

Solvent extraction, separation and recovery of lanthanum(III) and cerium(IV) from monazite sand by N-phenylbenzo-18-crown-6 hydroxamic acid

Y K Agrawal*, S B Vora & G Shah

 

A new N-phenylbenzo-18-crown-6-hydroxamic acid is reported for the separation of lanthanum(III) and cerium(IV) from monazite. Lanthanum(III) and cerium(IV) have been extracted and separated in presence of thorium, uranium and other associated cations at pH 8.8 and 9.5, respectively, in dichloromethane. Lanthanum(III) gives a colourless complex with the reagent which is extracted into dichloromethane and has molar absorptivity of 9.0 103 L mol-1 cm-1 at 385 nm. Cerium(IV) forms a red colour complex with the reagent extracted in dichloromethane with lmax 450 nm and molar absorptivity 6.5 103 L mol-1 cm-1. For trace determination, the extracts are inserted directly into the plasma for ICP-AES measurements of La(III) and Ce(IV) in the range of 4-80 ng mL-1 and 8-120 ng mL-1, respectively with the detection limit of 0.5 ng mL-1. The complexes of lanthanum(III) and cerium(IV) are very stable, (log b2k 20.20 and 20.50, respectively) as compared to those of thorium (1.60), uranium (1.80), and other related cations. The proposed method of preconcentration and analysis of La(III) and Ce(IV) is not adversely affected by highly ionic media, rendering the method suitable for their trace determination in sea water.

IPC Code: Int. Cl.7 G01N; C07C 59/00; C22B 59/00

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 504-510 

Synthesis, spectral and kinetic studies of copper(II) thiocarboxylates as molecular precursor for metal sulfide

Tarkeshwar Gupta & B P Baranwal*

 

A series of binary and ternary copper(II) complexes of thiocarboxylic acids and straight chain fatty acids with general formula Cu(SOCR)2(EtOH) and Cu(SOCR)(OOCR)(EtOH) [where R = CH3 or C6H5 and R = C7 H15, C11H23 or C13H27] have been synthesized and characterized. The binary copper(II) complexes have been investigated for their potential to act as precursors for the formation of metal sulfide materials. These species are expected to undergo thiocarboxylic anhydride elimination to give stoichiometric metal sulfides and remove the organic supporting ligands cleanly. The complexes are characterized by elemental and thermo gravimetric analyses, spectral  (IR, UV/Visible and ESR) and molar conductivity studies, molecular weight and magnetic moment measurements. The spectroscopic and analytical data have been found to be consistent with the identified formulae and the compounds are dimeric with bridging mode of coordination of the ligands. Magnetic data and ESR studies suggest strong antiferromagnetic coupling between two copper atoms. Thermal decomposition of binary copper(II) complexes in the solid state results in the formation of CuS at low temperature as seen by powder X-ray diffraction studies. The kinetic parameters of these complexes have been investigated on the basis of the respective thermal curves. The values of the activation energy (Ea) of thermal decomposition, reaction order (n), frequency factor (A) and velocity constant (k) (in the Arrhenius kinetic equation), have been established from the thermal data. The preliminary studies reveal the great potential of this highly tailorable chemical system as precursors to metal sulfido species.

 

IPC Code: C07F1/08

 

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 511-515 

Molecular interactions in binary mixtures of anisole with benzyl chloride, chlorobenzene and nitrobenzene at 303.15 K: An ultrasonic, volumetric, viscometric and refractive index study

A Ali*, A K Nain, D Chand & B Lal

 

Densities, ultrasonic speeds, viscosities, and refractive indices of binary mixtures of anisole with benzyl chloride, chlorobenzene and nitrobenzene, including those of the pure liquids, have been measured at 303.15 K over the entire composition range. Using these experimental data, the deviations in isentropic compressibility, ultrasonic speed, viscosity and refractive index, excess molar volume, excess free energy of activation of viscous flow, excess rheochore, partial molar compressibility and volume of benzyl chloride, chlorobenzene and nitrobenzene in anisole at infinite dilution, have been calculated. The variations of these properties with composition suggest that the strength of interactions in these mixtures follow the order: benzyl chloride > nitrobenzene > chlorobenzene.

IPC Code: Int. Cl.7 G01N; B01J 19/10

 

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 516-520 

Ruthenium (I) complexes with 4-ethoxy-phenyl tellurol: X-ray crystal structure of complex [Ru2(CO)4(m-TeC6H4OCH2CH3-4)2 (m-dppm)] (dppm=Ph2PCH2PPh2)

 Noorjahan Begum, Md Iqbal Hyder, Shahidul Islam, Shariff E Kabir, Kalipada Kundu* & K M Abdul Malik*

 

The reaction of [Ru3(CO)10(m-dppm)] (dppm=Ph2PCH2PPh2) with two molar equivalents of Te2Ar2 (Ar = C6H4OCH2CH3-4) in refluxing THF for 6 h gave the known complex [Ru2(CO)4 (m-TeAr)2(m-dppm)] 11 together with two new complexes [Ru2(CO)6(m-TeAr)2] 2 and cis-[Ru(CO)4(h1-TeAr)2] 3. Complex 1 has been structurally characterized by X-ray crystallography. Both Ru atoms are in highly distorted octahedral geometry. For each Ru, two CO groups in cis positions, the other bonded Ru atom and the Te atom of a bridging TeAr ligand occupy equatorial sites, and the Te atom of the other bridging TeAr ligand and a P atom of the bridging dppm ligand are in trans positions. Thus, in complex 1, the Te atom of one TeAr group lies in the Ru2P2 plane while that of the second TeAr group at a point nearly perpendicular to this plane, making the two TeAr groups non-equivalent but keeping the two P atoms of the bridging dppm ligand in equivalent positions.

IPC Code: Int. Cl.7 C0715/00; G01N23/00

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 521-525 

Ruthenium complexes containing bridging dppm and benzene-1,2-dithiolato ligands: X-ray crystal structure of [Ru2(CO)4{m-S(C6H4)S}(m-dppm)]

Noorjahan Begum, Md. Iqbal Hyder, Shariff E Kabir* & Kalipada Kundu

 

The reaction of benzene-1,2-dithiol with [Ru3(CO)10(m-dppm)] 1 in refluxing THF afforded two new compounds [Ru2(CO)4{m-S(C6H4)S}(m-dppm)] 2 and [Ru3(CO)8{m-S(C6H4)S}(m-dppm)] 3 which were characterized by elemental analysis, infrared, 1H and 31P{1H} NMR and mass spectra. The structure of  2 was determined by single crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P21/n, with a=10.3133(2), b=16.9806(3), c=19.5605(3) , a=90, b=100.2298(11), g=90, V=3371.10(10) 3 and Z=4. Both Ru atoms are in distorted octahedral geometry. For each ruthenium, two CO groups in cis positions, one bridged S atom and the other bonded Ru atom occupy the equatorial sites, and the other bridged S atom and a P atom of the bridging dppm ligand are in trans positions on the meridional axis. Of the two S atoms, one lies in the Ru2P2 plane while the other is perpendicular to this plane, thus making them nonequivalent but keeping the two P atoms of the bridging dppm ligand identical. The 50-electron compound 3 contains a doubly briddging dithiolato and a bridging dppm ligand. Protonation of 2 with trifluroacetic acid results in the formation of the cationic hydrido species [(m-H)Ru2(CO)4{m-S(C6H4)S}(m-dppm)]+ which has been characterized by spectroscopic data.

 

IPC Code: C07F15/00; G01N23/00

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 526-528

 

 Kinetic determination of traces of Al(III) ion by its catalytic effect on oxidation of 4-hydroxycoumarin by potassium permanganate

R P Igov, R M Simonović, T G Pecev* & B B Veselinović

 

Oxidation of 4-hydroxycoumarin by potassium permanganate in acid media of acetate buffer is catalyzed by Al(III) ions, which is the basis of the proposed new homogeno-catalytic method for determination of Al(III) in solutions. Under the optimum conditions, Al(III) has been determined at 525 nm in solutions containing analyte at 50-1000 ng/ml with probable relative error of 15.6-5.1 % and detection limit of 20 ng/ml. Appropriate kinetic equations for both catalytic and noncatalytic processes have been derived and the mechanism of catalytic effect of Al(III) investigated. Interference studies show that most of the common cations and anions do not interfere.

IPC Code: Int. Cl.7: C07B33/00

 

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 529-530 

Pulse polarographic determination of organoisothiocyanates and a method for the analysis of Ditrapex

B C Verma*, Chetan Chauhan, Lata Thakur & D K Sharma

 

Pulse polarographic analysis shows that in acetonitrile medium, n-butylamine transforms organoisothiocyanates quantitatively into the corresponding thiourea derivatives which yield well-defined diffusion controlled anodic waves in the presence of aqueous sulphuric acid (pH 2-3) and potassium perchlorate (supporting electrolyte). The method has been successfully adapted for the analysis of Ditrapex, an insecticide formulation containing methyl isothiocyanate.

IPC Code: Int. Cl.7 G01N27/48

 

 

Indian Journal of Chemistry

Vol. 44A, March 2005, pp. 531-534

 

Separation of gold and silver using a chelating resin Thiosemicarbazide incorporated Amberlite IRC-50

Kamalika Roy & S Basu*

 

A thiosemicarbazide group incorporated into a weakly acidic resin, Amberlite IRC-50 can selectively entrap two noble metals, gold and silver. The exchange capacity of the newly formed resin for Au(III) and Ag(I) is satisfactory. The resin can be utilized for the separation of these noble metals from different complex matrices.

IPC Code: Int. Cl.7: B01J39/00; C22B11/00