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Indian Journal of Chemistry

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

 

VOLUME 42A

NUMBER 12

DECEMBER 2003

 

CONTENTS

Papers

2921

 Recoil implosion via nuclear activation for the synthesis of endohedral radiofullerenes

 

 Tibor Braun* & Henrik Rausch

 

 

 The use of nuclear recoil implosion for producing radioactive endohedral and cage-labelled fullerenes is presented, with special emphasis on the energy of chemical effects after nuclear particle capture. The different possibilities using (n,g), (n,a), (p,n), (g,an) and (g,n) nuclear reactions are described.

2925

Liquid membrane based separations of actinides and fission products

 

 P K Mohapatra & V K Manchanda*

 

 

Liquid membrane based separation studies of actinides and fission products are reviewed. Emulsion liquid membrane and hollow fibre based non-dispersive solvent extraction methods are reported to be more efficient than the solvent extraction based separation methods.

 2939

 Flow injection spectrophotometric determination of As(III) and As(V) using molybdate reagent with solid phase extraction in-valve column

 

 

 Kate Grudpan*, Ngarmnet Worakijcharoenchai, Ponlayuth Sooksamiti, Jaroon Jakmunee & Gary D Christian

 

 

 2945

 Solvent extraction separation of thallium(III) from associated elements with hexaacetyl calix(6)arene

 S M Khopkar* & C Malkhede

 

 

Trace amount of thallium has been quantitatively extracted with hexaacetyl calix(6)arene at pH 2.0 with toluene as the diluent. Thallium is stripped from organic phase with 2M hydrochloric, nitric or perchloric acid and determined spectrophotometrically.

2949

 Mediated electrocatalysis at the carbon paste electrode : The iron(III)/hydrogen peroxide model

 

 S Serradilla Razola, G Quarin & J-M Kauffmann*

 

 

Theoretical aspects of homogeneous mediated electrocatalysis have been applied to the catalytic electroreduction of dissolved Fe(III) at carbon based electrode in the presence of hydrogen peroxide. The second order rate constant obtained is in agreement with literature data at the dropping mercury electrode.

2954

Recovery of cobalt from secondary sector using extraction in Cyanex 923

 

 Bina Gupta, Akash Deep & Shiv N Tandon*

 

 

 A process for the recovery of pure Co(II) from spent
Co-Mn and Co-Mo catalysts by its extraction in Cyanex 923 is described. The metal ion is partitioned in the organic phase as H2CoCl4.2 Cyanex 923 and stripped with 1×10
-3 molL-1 H2SO4.

 2959

 Direct determination of metals in aerosols by impaction-graphite furnace atomic absorption spectrometry—An update and new application

 

 Joseph Sneddon

 

 

Selected metals have been determined in the plume or smoke from burning Venezuelan crude oil by impaction-graphite furnace atomic absorption spectrometry. The relatively volatile metals, cadmium and zinc, and medium volatile metals, lead and manganese, are removed while the non-volatile metal, vanadium, is not removed in smoke from burning oil.

 2963

 Flame atomic absorption spectrometric determination of trace amounts of cobalt in standard alloys and biological samples after preconcentration of its 1,10-phenanthroline complex on tetraphenylborate-microcrystalline naphthalene adsorbent

M A Taher & B K Puri*

 

 

A flame atomic absorption spectrometric method has been developed for the determination of trace amounts
of cobalt. Cobalt is retained quantitatively as
1,10-phenanthroline-tetraphenylborate ion-associate complex on microcrystalline naphthalene in the pH range 2.6-9.5. Alternatively, the cobalt complex can be retained on ammonium tetraphenylborate-naphthalene adsorbent packed in a column.

2968

 Disposable electrochemical sensors and biosensors for environmental and food analysis

 

 

 Serena Laschi, Ilaria Palchetti,
Giovanna Marrazza & Marco Mascini*

 

 

Disposable electrochemical sensors and biosensors applied to environmental and food analysis are presented. Screen-printed electrochemical transducers, produced by thick-film technology, have been modified to get the specificity of the devices for their target. The sensors are coupled with fast and sensitive electroanalytical techniques to obtain accurate results in a few minutes.

 2974

 Synthesis and characterization of a mercury selective phase of acrylamide tin(IV) phosphate hybrid ion exchanger: Separation of Hg(II) from Cd(II), Pb(II) and Sr(II)

K G Varshney* & Puja Gupta

 

 

A new thermally stable phase of hybrid inorgano-organic material has been synthesized by anchoring acrylamide tin(IV) phosphate and characterized. The material is found to be highly selective for Hg(II).

2978

Relationship between extraction properties and transport through liquid membrane of amino acids by calixarene derivatives

 Lucia Mutihac*, Hans-Jürgen Buschmann &  Radu Mutihac

 

 

 The extractability and the transport of amino acid methylesters through chloroform liquid membrane in the presence of tropaeolin 00 are controlled by the structure of calixarene, the nature of amino acid and the nature of the anion used as ion pair for cation-receptor complexes.

2982

 Thermoanalytical studies on the non-isothermal dehydration and decomposition of dl – lactates of a series of transition metals

 

 

Ranjit K Verma*, Lata Verma &
Mukesh Chandra

 

 

 The non-isothermal decomposition of a series of
dl-lactate hydrates of chromium(III), manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) are studied with dry air as the purge gas and heating rate programmed at 10 Kmin-1. The activation energy for the dehydration steps is less than 60 kJmol
-1, while the entropy of activation has a high magnitude in each case indicating appreciable degree of rearrangement.

 

 2988

Spectrofluorimetric and cyclodextrin -enhanced spectrofluorimetric methods for the determination of naphazoline in nasal and eye drops

 Jamshid L Manzoori* & Mohammad Amjadi

 

 

 A spectrofluorimetric method has been developed for the determination of naphazoline. Formation of inclusion complexes of naphazoline in the β-cyclodextrin cavity enhances the sensitivity and limit of its detection as compared to that in the absence of cyclodextrin.

 2993

 Solid phase microextraction of residues of organophosphorus pesticides from aqueous samples for their determination by gas chromatography-mass spectrometry

 Vandana Singh, Archana Jain &
Krishna K Verma*

 

 

The nature of fibre, equilibration time and the presence of sodium chloride influence significantly the extraction efficacy of organophosphorus pesticides by solid phase microextraction.

 3000

 Liquid - liquid extraction, preconcentration and trace determination of selenium with rotaxane

 

Y K Agrawal*, S K Menon & Yauvan Pancholi

 

 

A rapid and sensitive method for the extraction and spectrophotometric determination of Se(IV) with
[2]-(1,10-bis trityloxy decane)(1, 4, 7, 10, 13,16,19, 22, 25, 28 - decaoxa cyclotriacontane)rotaxane has been described. Selenium is separated and determined in the presence of tellurium.

 3006

 5-Cyano-6-(4-pyridyl)-2-thiouracil as a building block in transition metal bipyridyl chemistry

 

 L Mishra* & B Pathak

 

 

The multifunctional ligand 5-cyano-6-(4-pyridyl)-2-thiouracil has been prepared and used in the synthesis of polymeric complexes with copper and zinc. The geometry around each Cu(II) centre is found to be distorted octahedral whereas Zn(II) complexes possess octahedral geometry.

 3012

 Extraction of certain radionuclides by bipicolinamides as new extractants from nitric acid medium

 

 E A Mowafy*, A M Shalash & I M El-Naggar

 

 

The extracting ability of two new symmetrical bipicolinamides (pyridine 2,6-dicarboxamide), viz.,
N,N
¢-tetrahexyl bipicolinamide and N,N¢-tetra-
(2-ethylhexyl) bipicolinamide for U(VI), Th(IV) and Fe(III) and some selected fission products such as Cs, Sr(II), Co(II) and Eu(III) from nitric acid solutions is reported.

3017

 Supercritical fluid extraction of cobalt

P M Saji, I C Bhoir, A M Bhagwat &
M Sundaresan*

 

 

The parameters for the kinetically controlled extraction of PC-88A coordinated cobalt(II), using cosolvated supercritical fluid carbon dioxide, have been studied.

3021

Electrical conductance studies of ISE membranes with different compositions at different temperatures

 Vipin Agarwala & M C Chattopadhyaya*

 

 

 Electrical conductance of Aliquat perrhenate, Aliquat nitrate, Aliquat iodide, Aliquat bromide and lithium Aliquat has been measured in the temperature range
of 25-85°C. All the membranes behave like semiconductors.

3025

Determination of cadmium, lead, copper, antimony and bismuth in high purity arsenic and arsenous oxide by differential pulse anodic stripping voltammetry

 

Suvarna Sounderajan & M M Palrecha*

 

 

 

3027

 Ortho-substituted aniline-N-salicylidenes as corrosion inhibitors for zinc in sulphuric acid

 

M N Desai, J D Talati & Neesha K Shah*

 

 

The corrosion inhibiting activity of ortho-substituted aniline-N-salicylidenes for zinc in sulphuric acid is studied. The inhibitors appear to function through adsorption due to the presence of the imine group and conjugated double bonds.

 3036

 Microdetermination of anti-hypertensive drug Captopril using 2,6-dichlorophenol indophenol

 

 

 Ashutosh Srivastava*, Bindu Khare,
Rupali Argal & Sandeep Patel

 

 

A spectrophotometric method has been developed for quantitative microdetermination of the antihypertensive drug, Captopril, in vitro as well as in vivo samples, with 2,6-dichlorophenol indophenol [2,6-DCPIP]. The sulphydryl moiety of Captopril is quantitatively oxidized to its corresponding [1,1¢-dithiobis¢ (2-methyl-1-oxopropane-3,1-diyl) bis-l-proline] disulphide by
2,6-DCPIP.

 

3041

 

Synthesis of a new cesium selective calix[4]arene based chromoionophore

 

 

 

  V Arora, H M Chawla*, T Francis, M Nanda & S P Singh

 

 

 3045

 Annual Index

Authors for correspondence are indicated by (*)

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2921-2924

 

Recoil implosion via nuclear activation for the synthesis of endohedral radiofullerenes

Tibor Braun*  & Henrik Rausch

 

The use of nuclear recoil implosion for producing radioactive endohedral and cage-labelled fullerenes is presented, with special emphasis on the energy of chemical effects after nuclear particle capture. The different possibilities using (n,g, (n,a), (p,n), (g,an) and (g,an) and (g,n) nuclear reactions are treated in detail.

 

  

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2925-2938

  

Liquid membrane based separations of actinides
and fission products

P K Mohapatra & V K Manchanda*

 

Separation of actinides and fission products is a challenging task for the chemists working at various stages of the nuclear fuel cycle, the most important being the reprocessing and waste management processes involved at the tail end. Amongst the various separation techniques, liquid membrane based separation methods are getting increasingly popular due to factors such as ligand economy, high efficiency, and low in power consumption and easy scale-up due to a compact design etc. Techniques such as emulsion liquid membrane and hollow fibre based non-dispersive solvent extraction methods are reported to be more efficient than the solvent extraction based separation methods which are limited by emulsion / third phase or crude formation. The present review is a compilation of literature reports on liquid membrane based separation studies involving mainly the actinides and fission products.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2939-2944

 

Flow injection spectrophotometric determination of
As(III) and As(V) using molybdate reagent with
solid phase extraction in-valve column

Ngarmnet Worakijcharoenchai, Ponlayuth Sooksamiti, Jaroon Jakmunee,

Gary D, Christian & Kate Grudpan*

 

Flow injection (FI) spectrophotometry for speciation of As(III) and As(V) has been investigated. As(III) in a mixture of AsO2- and AsO43- merging with IO3- will convert into As(V). The total AsO43- forms heteropoly acids with molybdate reagent. Mo(VI) is subsequently reduced to Mo(V). The compound in the stream flows into an in-valve microcolumn packing with C18 resin. The sorbed As-complex is eluted and continuously monitored by an LED colorimeter. The signal corresponds to the sum of AsO2- and AsO43-. A signal obtained without merging with IO3- is of the AsO43- alone in the mixture. Optimization for the conditions has been investigated. Single standard As(V) calibration is possible. Application to a sample free from phosphate such as water leachates of zinc ores has been demonstrated.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2945-2948

 

Solvent extraction separation of thallium(III) from associated elements with  hexa-acetyl calix(6)arene

S M Khopkar* & C Malkhede

 

Trace amount of thallium has been quantitatively extracted with hexa-acetyl calix(6)arene at pH 2.0 with toluene as the diluent. Thallium is stripped from organic phase with 2M hydrochloric, nitric or perchloric acid and determined spectrophotometrically. The 3-5 min equilibration period is adequate for complete extraction. A large number of ions are tolerated during the process of extraction. However, uranium, antimony, tin and lead show strong interference. Thallium is extracted in the presence of multi component mixtures containing thorium, bismuth, manganese, chromium and iron and separated selectively with stripping agents (mineral acids). Gallium and indium have been separated by selective extraction with oxine. The proposed method is extended for the analysis of thallium from real samples of soil, sediments and analogus products. The method is simple, rapid and selective with relative standard derivation of ±1.5%.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2949-2953

 

 

Mediated electrocatalysis at the carbon paste electrode: The iron(III)/hydrogen peroxide model

S Serradilla Razola, G Quarin & J-M Kauffmann*

 

Theoretical aspects of homogeneous mediated electrocatalysis have been studied and applied to the catalytic electroreduction of  dissolved Fe(III) at a carbon based electrode in the presence of  hydrogen peroxide. The electrocatalytic reduction of Fe(III) has been studied by cyclic voltammetry  and the kinetic constant of the rate-determining step, i.e., the reaction between Fe(II) and hydrogen peroxide has been determined. The second order rate constant obtained  (f = 70 M-1 s-1) is in agreement with literature data at the dropping mercury electrode.

 

  

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2954-2958

  

Recovery of cobalt from secondary sector using
extraction in Cyanex 923

Bina Gupta, Akash Deep & Shiv N Tandon*

 

A process for the recovery of pure Co(II) from spent Co-Mn and Co-Mo catalysts by its extraction in Cyanex 923 is described. The metal ion is partitioned in the organic phase as H2CoCl4.2 Cyanex 923 and stripped with a solution of 1×10-3 molL-1 H2SO4. The extractant is stable towards prolonged contact with HCl and shows negligible loss in extraction capacity even after recycling for twenty cycles. The partition data have been utilized for developing conditions for the separation of Co(II) from other metal ions, viz., Mo(VI), Al(III), Cr(III), Fe(III), Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II). The separation technique has been extended for the recovery of around 95% Co(II) from spent catalysts. The purity of the metal ions thus obtained approximates to 99%.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2959-2962

 

Direct determination of metals in aerosols by impaction-graphite furnace atomic absorption spectrometry—An update and new application

 Joseph Sneddon

 

Using impaction-graphite furnace atomic absorption spectrometry, the determination and concentration of selected metals in the plume or smoke from burning Venezuelan crude oil in a few seconds under controlled conditions in the laboratory are presented. Concentrations for relatively volatile (cadmium and zinc) and medium volatile metals (lead and manganese) are removed in the smoke whereas non-volatile metals (vanadium) are not removed in smoke from burning oil.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2963-2967

 

Flame atomic absorption spectrometric determination of trace amount of cobalt in standard alloys and biological samples after preconcentration of its 1,10-phenanthroline complex on tetraphenylborate – microcrystalline naphthalene adsorbent

 M A Taher &B K Puri*

 

A rapid, simple and sensitive method has been developed for determination of trace amount of cobalt using flame atomic absorption spectrometry. Cobalt is quantitatively retained as 1,10-phenanthroline-tetraphenylborate ion-associate complex on microcrystalline naphthalene in the pH range 2.6-9.5 from a large volume of its aqueous solutions of various standard alloys and biological samples. After filtration, the solid mass consisting of the cobalt complex and naphthalene is dissolved in 5 mL of dimethylformamide (DMF) and the metal is determined using flame atomic absorption spectrometry by measuring the absorbance at 240.7 nm. Cobalt-1,10-phenanthroline complex can alternatively be quantitatively retained on ammonium tetraphenylborate-naphthalene adsorbent packed in a column at a flow rate of 2 mL/min under the same conditions and determined similarly. In this case, 1.0 mg of cobalt is concentrated in a column from 400 mL of its aqueous sample, where its concentration is as low as 2.5 ppb. Eight replicate determinations of 4.0 ppm cobalt gives a mean absorbance of 0.120 with a relative standard deviation of 1.8%. The sensitivity for 1% absorption is 147 ppb. The conditions have been optimized and utilized for trace determinationof cobalt in various standard samples.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2968-2973

 

Disposable electrochemical sensor and biosensor for environmental and food analysis

Serena Laschi, Ilaria Palchetti, Giovanna Marrazza & Marco Mascini*

 

Disposable electrochemical sensors and biosensors applied to the environmental and food analysis are presented. For this purpose screen-printed electrochemical transducers, produced by thick-film technology, have been modified in order to get the specificity of the devices for their target. The sensors are coupled with fast and sensitive electroanalytical techniques such as differential pulse voltammetry (DPV), square wave voltammetry (SWV), chronopotentiometry at constant current, or chronoamperometry to obtain accurate results in few minutes. Applications to heavy metal, DNA damage and polychlorinated biphenyls (PCB) detection have been reported.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2974-2977

 

Synthesis and characterization of a mercury selective phase of acrylamide tin(IV) phosphate hybrid ion exchanger: Separation of Hg(II) from Cd(II), Pb(II) and Sr(II)

K G Varshney* & Puja Gupta

 

A new thermally stable phase of hybrid inorgano-organic material has been synthesized by anchoring organic moiety, acrylamide tin(IV) phosphate and characterized by IR, TGA, DTA and XRD studies in addition to its ion-exchange studies such as determination of ion-exchange capacity, elution, pH titration and distribution behaviour. The distribution behaviour towards several metal ions in different media/concentration have also been studied and the material is found to be highly selective for Hg(II). Some binary separations of the metal ions have been performed on a column of this material. The X-ray studies reveal the amorphous nature of the material.

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2978-2981

 

Relationship between extraction properties and transport through liquid membrane of amino acids by
calixarene derivatives

Lucia Mutihac*, Hans-Jürgen Buschmann & Radu Mutihac

 

The relationship between the extraction ability of p-tert-butylcalix[n, n=6,8]arenes upon some amino acid methylesters and their transport through chloroform liquid membrane in the presence of tropaeolin 00 ([4-(4¢-anilinophenylazo)benzene sulphonic acid]) at pH = 5.0 has been investigated. Our results highlighted that both the extractability and the transport of amino acid methylesters are essentially controlled by the structure of calixarene, the nature of amino acid, and the nature of the anion used as ion pair for cation-receptor complexes. Also the relationship between the extractibility of these complexes and the structure of amino acids under study have been discussed.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2982-2987

 

Thermoanalytical studies on the non-isothermal dehydration and decomposition of dl- lactates of a series of transition metals

Ranjit K Verma*, Lata Verma & Mukesh Chandra

 

The non-isothermal decomposition of a series of dl-lactate hydrates of chromium (III), manganese (II), iron (II), cobalt (II), nickel (II), copper (II) and zinc (II) have been studied with dry air as the purge gas and heating rate programmed at 10 Kmin-1. The a-T plots obtained from the TG data of none of the purely dehydration steps and the decomposition steps of cobalt (II) and zinc (II) compounds show any induction period indicating no physical desorption, nucleation or branching while the a-T plots of the other decomposition phenomena show a period of induction thus indicating that physical desorption and nucleation are taking place. The TG data of the dehydration steps have also been analyzed using various differential, difference-differential, and integral methods viz. Freeman-Carroll, Horowitz-Metzger, Coats- Redfern, Zsako, Fuoss-Salyer-Wilson and Karkhanavala-Dharwadkar methods. Values of activation entropy, Arrhenius factor, activation entropy and order of reaction have been approximated and compared. All the values of activation energy (E) for the dehydration steps are less than 60 kJmol1as expected for removal of weakly bound water of crystallization from such compounds. The entropy of activation (DS#) values have high magnitude in each case (<-150 JK-1mol-1) indicating appreciable degree of rearrangement.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2988-2992

 

Spectrofluorimetric and cyclodextrin-enhanced spectrofluorimetric methods for the determination of naphazoline in nasal and eye drops

Jamshid L Manzoori* & Mohammad Amjadi

 

A spectrofluorimetric method has been developed for the determination of naphazoline based on its fluorescence activity. This method allows the determination of 0.1-3 mg ml-1 naphazoline in aqueous solution with excitation and emission wavelengths of 281 and 330 nm respectively. The complexation between naphazoline and b-cyclodextrin gives a 1:1 complex.  A cyclodextrin-enhanced spectrofluorimetric method has also been developed which has better sensitivity and limit of detection (15 ng ml-1) as compared to that in the absence of cyclodextrin. Both methods have been applied satisfactorily to the determination of naphazoline in pharmaceutical preparations.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 2993-2999

 

Solid phase microextraction of residues of organophosphorus pesticides from aqueous samples for their determination by gas chromatography-mass spectrometry

Vandana Singh, Archana Jain & Krishna K Verma*

 

While studying the individual parameters on the extraction efficacy of organophosphorous pesticides (OPPs) in aqueous samples by solid phase microextraction, the nature of fibre, equilibration time and the presence of salt (sodium chloride used) show significant influence on the process. Polyacrylate (PA) fibre, 85 mm, has been found  to be considerably more effective than polydimethylsiloxane (PDMS), not only in the optimum recovery but also in the extraction of all eleven tested OPPs as compared to six by 100 mm PDMS and two by 7 mm PDMS. Optimum equilibration is reached in 60 min at 26oC with PA fibre. Salt concentration significantly decreases the extraction while other parameters such as desorption time (5 min or longer) and sample pH (5-7.5) do not have any influence. GC-MS has been carried out in the scan mode (m/z 45-450) and quantitation by selected ion extraction. Rectilinear calibration graph is obtained in the range 0.05-50 mg l–1 OPPs, the correlation coefficient (r) being between 0.9982 and 0.9999. The RSD in the analysis of 2 mg l–1 OPPs ranges from 2.5 to 4.6%, and the limit of detection is found to be 14-62 ng l–1. The method could be used for the analysis of OPPs in natural aqueous samples, and one example of its application to vegetable extract has been demonstrated.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3000-3005

 

Liquid-liquid extraction, preconcentration and trace determination of selenium with rotaxane

 Y K Agrawal*, S K Menon & Yauvan Pancholi

 

A rapid and sensitive method for the extraction and spectrophotometric determination of Se(IV) with [2]-(1,10-bis trityloxy decane)(1, 4, 7, 10, 13,16,19, 22, 25, 28-decaoxa cyclotriacontane)rotaxane (TDDCR), has been described. Selenium forms a colourless complex with TDDCR which is extracted in chloroform (molar absorptivity 3.18´103 l mol-1 cm-1) and obeys Beer’s Law in the range of 0.62-16.25 ppm for Se(IV). The extract is directly inserted in the plasma for ICP-AES measurement of selenium which enhances the sensitivity several folds with the detection limits of 1.5 ppb. The overall formation (b2K′) and distribtution (Ke) constants calculated are 11.56±0.03 and 2.0±0.05´10-8, respectively. Selenium has been separated and determined in presence of tellurium.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3006-3011

 

5-Cyano-6-(4-pyridyl)-2-thiouracil as a building block in transition metal bipyridyl chemistry

L Mishra* & B Pathak

 

Multifunctional ligand 5-cyano-6-(4-pyridyl)-2-triiouracil (LH2) has been prepared and used in the synthesis of polymeric complexes. The general compositions of the complexes (M bpyLH2 Cl2)n. [M=Cu(II) and Zn(II)] have been assigned on the basis of their elemental analysis and spectroscopic (IR, NMR, UV-visible and EPR) data. FAB mass data recorded upto 1000 range also support higher composition of the complexes. Powder X-ray diffraction, optical microscopic and scanning electron microscopic (SEM) studies have also been carried out. Force field calculations have been carried out to simulate the energy minimized structures of the dimeric unit of the complexes. The geometry around each Cu(ll) centre has been found to be distorted octahedral whereas Zn(ll) complexes possess octahedral geometry. Solid state conductance has also been measured at room temperature as well as at higher temperatures.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3012-3016

 

Extraction of certain radionuclides by bipicolinamides as a
new extractants from nitric acid medium

E A Mowafy*, A M Shalash & I M El-Naggar

 

Two new symmetrical bipicolinamides (pyridine2,6-dicarboxamide), viz., N, N'-tetrahexyl bipicolinamide (THBPA) and N, N'-tetra-(2-ethylhexyl) bipicolinamde (TEHBPA) have been synthesized and characterized. The extracting ability of these extractants for U(VI), Th(IV) and Fe(III) and some selected fission products such as Cs, Sr(II), Co(II) and Eu(III) from nitric acid solutions have been compared with that of the two parallel structure monoamides(pyridinr4-carboxamide), viz., N,N'-dihexyl isonicotainamide (DHINA) and N,N'-di-(2-ethylhexyl)-isonicotainamide (DEHINA). TEHBPA shows higher extraction efficiency for U(VI), Th(VI) and Fe(III) than THBPA. A systematic investigation has been carried out on the extraction behavior of U(VI) with the two newly prepared bipicolinamides. The stoichiometry of the extracted species of U(VI) conforms to UO2(NO3)2.2 (bipicolinamides). The extraction behavior of U(VI), Th(IV) and Fe(III) with gamma-irradiated bipicolinamides and monoamides has been studied as a function of absorbed doses.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3017-3020

  

Supercritical fluid extraction of cosolvated, cobalt with PC88A

P M Saji, I C Bhoir, A M Bhagwat & M Sundaresan*

 

Cosolvated supercritical fluid carbon dioxide has been investigated for its potential for the kinetically controlled extraction of coordinated cobalt ions with 2-ethyl hexyl 2-ethyl hexyl phosphonic acid as the complexing agent. Hexamine has been used as the coordinating agent and heptane as the cosolvent. A mixture of cobaltous chloride and hexamine with a small quantity of water was made to react dynamically with the complexing agent in heptane in the medium of supercritical fluid carbon dioxide (SCF CO2). Extraction efficiencies have been found as a function of time and the optimum pressure-temperature regime established. The study has implications for the end purification of cobalt from nickel and may serve as a role model for the refining and purification of one rare earth element from its other rare earth impurities.

 

 

  

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3021-3024

  

Electrical conductance studies of ISE membranes with different compositions at different temperatures

Vipin Agarwala  & M C Chattopadhyaya*

 

Electrical conductance of different polymer coated membranes, namely, Aliquat perrhenate, Aliquat nitrate, Aliquat iodide, Aliquat bromide and lithium Aliquat has been measured in the temperature range of 25°-85°C. The studies indicate that the membranes behave like semiconductors.

 

  

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3025-3026

 

 

Determination of cadmium, lead, copper, antimony and bismuth in high purity arsenic and arsenous oxide by differential pulse anodic stripping voltammetry

 

Suvarna Sounderajan & M M Palrecha

 

A simple and rapid differential pulse anodic stripping method for simultaneous determination of cadmium, lead, copper, antimony and bismuth in high purity arsenic and arsenous oxides described. 2 M HCl was found to be the most suitable supporting electrolyte. This method is suitable for the determination of Cd, Sb, Bi (0.1 mg g-1), Cu(0.3 mg g-1) and Pb(0.5 mg g-1) (with about 100mg as sample) with a relative standard deviation of 15-20%.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3027-3035

 

 

Ortho-substituted aniline-N-Salicylidenes as corrosion inhibitors for zinc in sulphuric acid

M N Desai, J D Talati & Neesha K Shah*

 

The corrosion of zinc in sulphuric acid containing different o-substituted aniline-N-salicylidenes has been studied with respect to inhibitor and acid concentration, period of exposure and temperature. All the five compounds show high (95-97%) inhibitive efficiency. At 0.5% inhibitor concentration in 0.5 M acid, the order of efficiency is: o-HNS (95.5%) < o-CNS (96.8%) < o-AnNS (99.7%) ≤ o-TNS (99.8%) ≤ ANS (99.9%). The activation energies are higher in inhibited than in uninhibited acid. It appears that an efficient inhibitor is characterized by a relatively greater decrease in the free energy of adsorption. Galvanostatic polarization studies indicate that these are mixed type inhibitors with predominant action on the local cathodes. Cathodic protection in the presence of these inhibitors has been studied. The inhibitors appear to function through adsorption due to the presence of the imine (-C=N-) group and conjugated double bonds.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3036-3040

 

Microdetermination of anti-hypertensive drug Captopril using 2,6 diclorophenol indophenol

Ashutosh Srivastava*, Bindu Khare, Rupali Argal & Sandeep Patel

 

A method has been developed for quantitative microdetermination of antihypertensive drug Captopril in vitro as well as in vivo samples, spectrophotometrically using 2,6-dichlorophenol indophenol [2,6DCPIP]. The sulphydryl moiety, of the Captopril is quantitatively oxidized to its corresponding [1,1¢ dithiobis’(2 methyl-1-oxopropane-3,1 diyl)bis-L-proline]disulphide by 2,6DCPIP exhibiting stoichiometry of 2:1. The reaction product has been characterized by FTIR and NMR spectral studies. The method is rapid, accurate with high precision and can be applied for determining drugs in pharmaceutical preparations as well as in-vivo samples.

 

 

 

Indian Journal of Chemistry

Vol. 42A, December 2003, pp. 3041-3044

 

Synthesis of a new cesium selective calix[4]arene based chromoionophore

V Arora, H M Chawla*, T Francis, M Nanda & S P Singh

 

A novel azo-pyridyl calix[4]arene, (5,11,17,23-tetrakis(4¢-azopyridyl)-25,26,27,28-tetrahydroxycalix[4]arene), has been synthesized in the 1,3-alternate conformation by coupling debutylated calix[4]arene with a diazotized solution of 4-aminopyridine. The synthesized chromoionophore gives a large bathochromic shift (119 nm) with an increase in the intensity of absorption on addition of a methanolic solution of Cs2CO3. The selectivity coefficients for Cr3+ and Ni2+ has been determined to be KCr3+, Cs+ = 6.6 and KNi2+, Cs+ = 66, while other alkali and alkaline earth metal ions do not interfere. The synthesized calixarene derivative has the potential to be used for development of ionic filters.