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Indian Journal of Chemistry

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

 

 

 

VOLUME 43A

NUMBER 6

June 2004

 

CONTENTS

 

Papers

 1147

Aldehyde assisted wet chemical route to synthesize gold nanoparticles

  

Sudip Nath, Sujit Kumar Ghosh, Sudipa Panigrahi & Tarasankar Pal*

 

 Evolution of stable gold nanoparticles from an aqueous solution of HAuCl4 in the absence of any stabilizer is reported. Aqueous solutions of formaldehyde and acetaldehyde have been employed as effective reducing agents for the particle preparation.

 

 1152

Studies on the multielemental uptake by thiosemicarbazide incorporated Amberlite IRC-50 using tracer packet technique

  

Kamalika Roy, S Basu, Dalia Nayak &
Susanta Lahiri*

 

 The uptake of several carrier-free radiotracers has been studied using thiosemicarbazide incorporated amberlite IRC-50.

 

 1156

Partial molar adiabatic compressibilities and viscosities of some amino acids in aqueous 1,4-dioxane solutions at 298.15 K

 

 

T S Banipal* & Gagandeep Singh

 

 Apparent molar adiabatic compressibilities (Ks,2,f) and viscosities (h) of glycine, DL-a-alanine, L-valine, L-leucine and L-phenylalanine have been determined in 2.5, 5.0, 10.0, 20.0 and 25.0 % aqueous 1,4-dioxane solution at 298.15 K. Positive  values have been observed (except very small negative value for glycine at 2.5 %) for the studied amino acids, with the magnitude increasing with increase in concentration of 1,4-dioxane.

 1167

Catalytic reduction of NOx by ammonia over nickel and lanthanum supported on zeolite

 

  

 

 

A V Salker*  & W Weisweiler

 

The effects of oxygen and water on the reduction of NO by NH3 over metal supported H-ZSM-5 catalysts have been determined. Higher NOx reduction rate is obtained over Ni/ZSM-5 as compared with La/ZSM-5 and H-ZSM-5. In presence of water vapour, the NOx rate is lower than in the absence of water vapour. Oxygen promotes SCR reaction in forming reactive intermediate species for the reduction of NO by NH3.

 1172

A study of the structural characterization and cyclohexanol dehydrogenation activity of Cu/g-Al2O3 catalysts

   

Anita Rachel, V Durga Kumari*,  R Subramanian, K V R Chary & P Kanta Rao

 

 A series of Cu/g-Al2O3 catalysts has been prepared by wet impregnation of g-Al2O3 with aqueous cupric nitrate, varying the copper content from 0.4 to 18.7 wt% followed by calcination at 400˚C in air. TPR profiles show the presence of unreducible copper species at low loadings and reducible amorphous and bulk copper species at higher loadings. XRD pattern of the catalyst containing 10.2 wt% Cu after reaction shows the presence of a-Cu confirming the oxidative dehydrogenation of cyclohexanol on unreduced catalysts.

 1181

Impedance spectroscopy of binary solutions

 

 

 

Saadi Abdul Jawad*, Hamza Abdel-Halim, Hayel Shehadeh & Awni B Hallak

 

The dielectric properties of three binary mixtures of different molar ratios have been investigated in the frequency range 1 – 106 Hz at 25°C. The variation of ac conductivity with molar ratio of acetone–chloroform is typical of that observed for ideal binary solution. For methanol–water and ethyl ether–water, a sudden change has been observed in the conductivity at 30% by mass methanol and 20% by mass ethyl ether, respectively.

1186

Aggregation in oxidation of aspartic and glutamic acids by chloramine-T in presence of surfactants: A kinetic study

Ekta Pandey, Neeti Grover,  Neelu Kambo & Santosh K Upadhyay*

 

                  … (i)

                 … (ii)

            … (iii)

S´           Product

          (nitrile+aldehyde)

 

1193

Synthesis, characterization and crystal structures of binuclear cluster compounds [Me4N]2[TS4(AgCN)] (T = Mo, W)

   

A B M Shamsur Rahman, H Boller* &
K O Klepp

 

 

Notes

 1198

 Highly efficient transport of indium in bulk liquid membranes containing D2EHPA as carrier

 

   

 

H Ebrahimzadeh & Y Yamini*

 

 

 1202

Effect of impregnation sequence on oxidation activity and desorption properties of
Ag-Pd/Ce0.8Zr0.2O2 catalyst

 

 

Meng-fei Luo*, Zong-lan Yan & Rin Lin

 

 Ce0.8Zr0.2O2 supported Ag-Pd catalysts have been prepared by the impregnation method and characterized by ethanol-TPD, CO-TPD and XRD. Catalytic activity for ethanol and CO oxidation follows the order: Ag-Pd(C)/Ce0.8Zr0.2O2 > Ag-Pd(F)/Ce0.8Zr0.2O2 > Ag(F)-Pd/Ce0.8Zr0.2O2. XRD studies show that two Ag2O phases, cubic and hexagonal, are observed for all catalysts. Hexagonal Ag2O formed in the catalyst prepared by co-impregnation is the most active species to react with ethanol or CO adsorbed on the surface of the catalyst.

 1206

Sonochemical studies of aqueous solutions of chromium and manganese in their cationic and oxo-anionic states

 

  

Pankaj* & Manju Chauhan

 

 Effect of ultrasound on the oxidation, precipitation and chemical interaction of Cr(3+ , 6+) and Mn(2+ , 7+) ions in aqueous solutions have been examined. Mn2+ precipitates in the ultrasonic field above 0.02 M (1000ppm), whereas Cr3+ remains unaffected even up to 0.1M. Diphenyl carbazide (DPC) reduces Cr6+ to Cr3+ and forms a red-violet coloured complex, which decomposes upon sonication due to re-conversion of Cr3+ to Cr6+.

 1210

 Kinetics and mechanism of platinum(IV) catalysed oxidation of some hexoses by alkaline chloramine-T

 

Neelu Kambo & Santosh K Upadhyay*

 

 The kinetics of PtIV catalysed chloramine-T oxidation of glucose, galactose and fructose in alkaline medium have been investigated. The reactions are first order in oxidant, while the order of reaction in substrate and OH- decreases from unity at higher [substrate] and [OH-], respectively. Rate of reaction is proportional to {k¢ + k² [catalyst]}, where k¢ and k² are rate constants for uncatalysed and catalysed path, respectively.

 

1216

 Selective oxidation of benzyl alcohol with monochromate in non-polar solvents

 

K Bijudas & T D Radhakrishnan Nair*

 

 [Q+HCrO4- ] H2O                 [Q+HCrO4-] org

[Q +HCrO4-] org + PhCH2OH ® [PhCH2OCrO3- Q+] org + H2O

[PhCH2OCrO3Q+] org ® PhCHO + Cr (IV) + Q+ + H+

  

 1219

 Kinetics and mechanism of oxidation of some vicinal and non-vicinal diols by quinolinium bromochromate

 

Shweta Vyas & Pradeep K Sharma*

 

 

 1224

Mechanism of peroxide reactions : Kinetics of oxidation of sulfanilic acid by peroxomonosulfuric acid

   

Radhasyam Panda* & M Purna Ch Reddy

 

 The oxidation of sulfanilic acid by peroxomonosulfuric acid (PMSA) has been investigated in the pH range
0-12.5. The reaction obeys second order kinetics, first order each in [peroxomonosulfuric acid] and [sulfanilic acid] at constant pH. The mechanism of oxidation involves the nucleophillic attack of the nitrogen lone pair of unprotonated sulfanillic acid on the electrophilic peroxo–oxygen of PMSA species.

 

 1228

Phenol-amide chelates of cobalt(II), nickel(II), copper(II) and zinc(II) as catalysts for hydrolysis of active esters. Part II. Kinetics and mechanism of hydrolysis of 4-nitrophenylacetate by the metal(II) chelates of 1,2-bis(2-hydroxy-benzamido) ethane and 1,3-bis(2-hydroxy-benzamido) propane

  

Mahashweta Sahu, Guru C Pradhan,
Prakash Mohanty & Anadi C Dash*

 

                Kd

ML                    M(L-H)-  +  H+

+                              +

PNPA                     PNPA

 

k1                          k2

                Product

 

                kobs

PNPA   ¾®          Product

 1233

 Synthesis, characterization and nuclease activity of copper(II), nickel(II), cobalt(II) and iron(II) complexes with oxime-thiosemicarbazones

   

K Hussain Reddy*, M Surendra Babu,
P Suresh Babu & S Dayananda

 

 

 

 

 1239

 Heteroleptic tris-complexes of ruthenium(II/III) containing one bidentate Schiff base: Synthesis, characterisation and link-up of oxidation levels

   

Habibar Chowdhury, Doyel Bose,
Rajarshi Ghosh, Sk Hafijur Rahaman &
Barindra Kumar Ghosh*

 

 Mixed-tris chelates of Ru(II) and -(III) of general formula [RuL¢L2]z+ [L¢ = N-((pyridin-2-yl)formylidene)-aniline (pfan), N-((pyridin-2-yl)benzylidene)aniline (pban),
N-((pyridin-2-yl)formylidene)benzylamine (pfba) or
N-((pyridin-2-yl)benzylidene)benzylamine (pbba); L=2,  
2
¢-bipyridine (bpy), z = 2 or 3; L = 2-(m-tolylazo)-pyridine (tap), z = 2] have been prepared. The ruthenium(II) and rutheniun(III) complexes, respectively exhibit several MLCT and LMCT charge-transfer transitions in the 200-900 nm region.

 

 1245

 Synthesis and characterisation of iron(III) complexes of 1,2-dihydro-1-phenyl-2,3-dimethyl-4-[21,41-pentanedione-31- hydrazono]pyrazol-5-one

 

 

 

Reena Ravindran

 

 

 1249

Atomic absorption spectrometric determination of trace manganese after separation and preconcentration with 1-(2-pyridylazo)-2-naphthol-naphthalene adsorbent

 

Mohammad Ali Taher

 

 An atomic absorption spectrometric method for the determination of trace amounts of manganese after adsorption of its 1-(2-pyridylazo)-2-naphthol complex on microcrystalline naphthalene has been developed. The complex is adsorbed on microcrystalline naphthalene in the pH range 8.9-10.2 from large volumes of aqueous solutions.

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1147-1151

 

Aldehyde assisted wet chemical route to
synthesize gold nanoparticles

Sudip Nath, Sujit Kumar Ghosh, Sudipa Panigrahi & Tarasankar Pal*

 

Evolution of stable gold nanoparticles from an aqueous solution of HAuCl4 in the absence of any stabilizer is reported. Aqueous solutions of formaldehyde and acetaldehyde have judiciously been employed as effective reducing agents for the particle preparation. The study indicates the differential reducing action of the aldehydes, which in turn gives an indication of the effect on the stability, size and shape of the evolved gold particles. The effect of temperature during the synthesis to have a control over the sizes has also been studied.

 

IPC Code: Int.Cl.7 B 82 B; C 22 B 11/00

 

 

 

Indian Journal of Chemistry

 Vol.  43A, June 2004, pp. 1152-1155

 

Studies on the multielemental uptake by thiosemicarbazide incorporated Amberlite IRC-50 using tracer packet technique

Kamalika Roya, S Basub, Dalia Nayaka & Susanta Lahiria*

 

Irradiation of a thick cobalt target with 16O, 7Li and 12C beams consecutively produces carrier-free radiotracers of 61Cu, 62,63Zn, 66,67Ga, 71,72As and 73Se, which are of nutritional importance and are closely related in the periodic table. A gold target irradiated with medium energy 7Li and 12C produces 197Hg, 198,199,200,201Tl, 199,200,201Pb, 204Bi and 204,205Po, which are heavy as well as toxic in the environment. A new term, ‘Tracer Packet’ has been coined for such systems. The uptake of these elements has been studied using a chelating resin, thiosemicarbazide incorporated amberlite IRC-50.

 

IPC Code: B 01 J 19/08

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1156-1166

 

Partial molar adiabatic compressibilities and viscosities of some amino acids in aqueous
1,4-dioxane solutions at 298.15 K

T S Banipal* & Gagandeep Singh

 

Apparent molar adiabatic compressibilities (Ks,2,f) and viscosities (h) of glycine, dl-a-alanine, l-valine, l-leucine and l-phenylalanine have been determined in 2.5, 5.0, 10.0, 20.0 and 25.0 % aqueous 1,4-dioxane solution at 298.15 K. These data have been used to calculate partial molar adiabatic compressibilities of transfer at infinite dilution (Dtr) and viscosity B-coefficients. Positive Dtr values have been observed (except very small negative value for glycine at 2.5 %) for the studied amino acids and their magnitude increases with increase in concentration of 1,4-dioxane. B-coefficient values for the studied amino acids in 1,4-dioxane are higher than the corresponding values in water. The activation energy for viscous flow in aqueous 1,4-dioxane solutions has been calculated from B-coefficient and partial molar volume data reported earlier. Hydration numbers, interaction coefficients and side chain contributions have also been calculated and these results have been discussed in terms of solute-cosolute interactions.

 

IPC Code:  Int. Cl.7 G 01 N

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1167-1171

 

Catalytic reduction of NOx by ammonia over nickel and lanthanum supported on zeolite

A V Salker* & W Weisweiler

 

The effects of oxygen and water on the reduction of NO by NH3 over metal supported H-ZSM-5 catalysts have been determined. The catalysts have been prepared by wet impregnation method and characterized by X-ray diffraction and BET surface area. Higher NOx reduction rate is obtained over Ni/ZSM-5 catalyst compared with La/ZSM-5 and H-ZSM-5. In presence of water vapour the NOx rate has been found to be lower than in the absence of water vapour. Oxygen promotes SCR reaction in forming reactive intermediate species for the reduction of NO by NH3.

 

IPC code: B01J 8/02; B01J 21/12

 

 

 

Indian Journal of Chemistry

Vol. 43A, June 2004, pp. 1172-1180

 

A study of the structural characterization
and cyclohexanol dehydrogenation activity of
Cu/g-Al2O3 catalysts

Anita Rachela, V Durga Kumari*a , R Subramanianb , K V R Charya, & P Kanta Raoa

 

A series of Cu/g-Al2O3 catalysts has been prepared by wet impregnation of g-Al2O3 with aqueous cupric nitrate solution varying the copper content from 0.4 to 18.7 wt% followed by calcination at 400˚C in air. These catalysts have been characterized by BET surface area, CO chemisorption, XRD, SEM, TPR and ESR. The TPR profiles show the presence of unreducible copper species at low loadings and reducible amorphous and bulk copper species at higher loadings. The ESR spectra of the unreduced and reduced Cu/g-Al2O3 catalysts clearly distinguish the Cu (II) ions in their clustered and isolated forms, giving an indication of the existence of an interaction between CuO and g-Al2O3 and also a definite change in the geometry depending on the Cu content. Catalytic activity of these catalysts has been studied for the dehydrogenation of cyclohexanol over unreduced and reduced catalysts at 200-300˚C. Structure–activity relationships of the catalysts are discussed. X-ray diffraction pattern of the catalyst containing 10.2 wt% Cu after reaction shows the presence of a-Cu confirming the oxidative dehydrogenation of cyclohexanol on unreduced catalysts.

 

IPC Code: B01J 21/04; C07B 35/04

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1181-1185

 

Impedance spectroscopy of binary solutions

 

Saadi Abdul Jawad*, Hamzeh M Abdel-Halim, Hayel M Shehadeh & Awni B Hallak

 

The dielectric properties of three binary mixtures of different molar ratios have been investigated in the frequency range 1 Hz to 106 Hz at 25°C. The variation of ac conductivity with molar ratio of acetone–chloroform is typical of that observed for ideal binary solution. For methanol–water and ethyl ether–water a sudden change has been observed in the conductivity at 30% by mass methanol and 20% by mass ethyl ether, respectively. The same phenomenon has been observed in all other electrical variables. This is attributed to the trend of the partial molar volumes of the different binary mixtures.

 

IPC Code: Int. Cl.7 G 01 R 27/02

 

 

 

Indian Journal of Chemistry

 Vol. 43A, July 2004, pp. 1186-1192

 

Aggregation in oxidation of aspartic and glutamic acids by chloramine-T in presence of surfactants:
A kinetic study

Ekta Pandey, Neeti Grover,  Neelu Kambo & Santosh K Upadhyay*

 

The kinetics of oxidation of aspartic and glutamic acids by chloramine-T in HClO4 medium have been investigated in the absence and presence of anionic (sodium lauryl sulphate), cationic (cetyltrimethylammonium bromide) and non-ionic (Brij 35) surfactants. In the absence of surfactant the rate of oxidation may be represented as,

where k and K are constants.

The presence of a small amount of surfactant (below its critical micelle concentration) strongly enhances the rate of oxidation and the observed rate constant attains constancy at higher surfactant concentration. Using Piszkiewicz's cooperativity model, the cooperative index n has been calculated for these reactions to be between 1-3, indicating the existence of catalytically productive submicellar aggregates. The values of n have been used to calculate the binding constants of reactants with the surfactant using Raghvan and Srinivasan's model proposed for biomolecular micellar catalysed reactions. The evaluated binding constants are in good agreement from those obtained by Piszkiewicz's model. The formation of aggregate is further supported by the enhancement of rate in presence of a common hydrotrope, namely, sodium benzoate.

 

IPC Code: Int. Cl.7 C 07 B 33/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1193-1197

 

Synthesis, characterization and
crystal structures of binuclear cluster compounds [Me4N]2[TS4(AgCN)] (T = Mo, W)

A B M Shamsur Rahmana, H Boller* & K O Klepp

 

Red-brown and orange-yellow crystals of [Me4N]2[MoS4(AgCN)] and [Me4N]2[WS4(AgCN)], respectively, have been obtained from the reactions of tetramethyl ammonium thiomolybdate and tungstate, [Me4N]2[TS4] (T = Mo, W), with AgCN in acetonitrile at room temperature. The complex anions have been characterized by infrared and mass spectroscopy. The crystal structures were determined from single crystal diffractometer data. The two compounds are isostructural, with space group P21. The lattice parameters are: a = 6.287(2) Å, b = 7.3740(7) Å, c = 20.602(8) Å, b = 92.59(2)°° (molybdenum complex), and a = 6.313(4) Å, b = 7.384(4) Å, c = 20.592(1) Å, b = 92.60(2)°° (tungsten complex). The crystal structures are characterized by a pseudo-hexagonal packing of stacks of the binuclear complex anions, [TS4(AgCN)]2-. The influence of the packing on the silver coordination is discussed.

 

IPC Code: C01B 31/00; C01C 3/08

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1198-1201

 

Highly efficient transport of indium in bulk liquid membranes containing D2EHPA as carrier

H Ebrahimzadeh & Y Yamini*

 

Bis(2-ethylhexyl) phosphoric acid (D2EHPA) has been used as a highly efficient carrier for the transport of indium ions through a carbon tetrachloride bulk liquid membrane. Using 5M HCl in the receiving phase, the amount of indium transported across the liquid membrane, after 2.5 hours was 96 ± 2%. The selectivity and efficiency of indium transport from acidic solution containing a competing ion has been investigated. Results showed that the interfering effect of the various ions tested on transport of indium ion was negligible.

 

IPC Code: C22B 58/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1202-1205

 

Effect of impregnation sequence on oxidation activity and desorption properties of Ag-Pd/Ce0.8Zr0.2O2 catalyst

Meng-fei Luo*, Zong-lan Yan & Rui Lin

 

Ce0.8Zr0.2O2 supported Ag-Pd catalysts have been prepared by the impregnation method and characterized by ethanol-TPD, CO-TPD and XRD. The effect of different impregnation sequences on catalytic activity for ethanol and CO oxidation has been investigated. The experimental results show that impregnation sequence has definite effect on the activity for ethanol and CO oxidation. Catalytic activity for ethanol and CO oxidation follows the order: Ag-Pd(C)/Ce0.8Zr0.2O2 > Ag-Pd(F)/Ce0.8Zr0.2O2 > Ag(F)-Pd/Ce0.8Zr0.2O2, and it corresponds with the temperature and intensity of the CO2 desorption peak in the CO-TPD process. Ethanol oxidation activity of the catalysts with different impregnation sequences correspond with the temperature and intensity of the desorption peak in ethanol-TPD process. XRD measurements show that there two Ag2O phases, cubic and hexagonal are observed for all catalysts. Only hexagonal Ag2O may favor the oxidation of ethanol or CO. Hexagonal Ag2O formed in the catalyst prepared by co-impregnation is the most active to react with ethanol or CO adsorbed on the surface of the catalyst.

 

IPC Code: B01J 21/06; B01J 23/07

 

 

 

Indian Journal of Chemistry

Vol. 43A, June 2004, pp.1206-1209

 

Sonochemical studies of aqueous solutions of chromium and manganese in their cationic and oxo-anionic states

Pankaj*  & Manju Chauhan

 

Effect of ultrasound on the oxidation, precipitation and chemical interaction of Cr(3+ , 6+) and Mn(2+ , 7+) ions in aqueous solutions has been examined. Mn2+ precipitates in the ultrasonic field above 0.02 M (1000ppm) concentration whereas Cr3+ remains unaffected even up to 0.1M concentration. Diphenyl carbazide (DPC) reduces Cr6+ to Cr3+ and forms a red-violet coloured complex, which decomposes upon sonication due to re-conversion of Cr3+ to Cr6+. Oxidative nature of Mn7+ for conversion of Cr3+ to Cr6+ is enhanced four folds under the experimental conditions. The decolourisation of the solution of this complex is only due to cavitation produced during sonication process.

IPC Code: Int Cl7. B01J19/10

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1210-1215

 

Kinetics and mechanism of platinum(IV) catalysed oxidation of some hexoses by alkaline chloramine-T

Neelu Kambo & Santosh K Upadhyay*

 

The kinetics of PtIV catalysed chloramine-T oxidation of glucose, galactose and fructose in alkaline medium have been investigated. The reactions are first order in oxidant, while the order of reaction in substrate and OH- decreases from unity at higher [substrate] and [OH-], respectively. Rate of reaction is proportional to {k¢ + k² [catalyst]}, where k¢ and k² are rate constants for uncatalysed and catalysed path, respectively. A positive effect of Cl- at lower [Cl-] and ionic strength has also been observed on the rate of oxidation. An evidence for the formation of 1:1 complex between PtIV and hexose has been obtained and a mechanism consistent with the kinetic data has been proposed.

 

IPC Code: Int. Cl.7 C 07 B 33/00; B 01 J 23/42

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1216-1218

 

Selective oxidation of benzyl alcohol with monochromate in non-polar solvents

K Bijudas & T D Radhakrishnan Nair*

 

Kinetics of the oxidation of benzyl alcohol in non-polar media has been carried out using potassium dichromate under phase transfer catalysis (PTC) using tetrabutylphosphonium bromide (TBPB) and tetrabutylammonium bromide (TBAB) as phase transfer catalysts (PT catalysts). The reaction is first order each in [benzyl alcohol] and [chromate ions]. The oxidation is selective in the product formation. Benzaldehyde is formed in quantitative yield and no traces of benzoic acid has been detected. The reaction mixture fails to induce the polymerization of added acrylonitrile which rules out involvement of any radical intermediate. The energy of activation is significantly low in the range 29-31 kJmol-1.

 

IPC Code: Int Cl.7 C 07 B 33/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1219-1223

 

Kinetics and mechanism of oxidation of some vicinal and non-vicinal diols by quinolinium bromochromate

Shweta Vyas & Pradeep K Sharma*

 

Kinetics of oxidation of four vicinal, four non‑vicinal diols and two of their monoethers by quinolinium bromochromate (QBC) have been studied in dimethyl sulphoxide (DMSO). The main product of oxidation is the corresponding hydroxycarbonyl compound. The reaction is first order each in QBC and the diols. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence is taking the form: kobs = a + b[H+]. The oxidation of [1,1,2,2‑2H4] ethanediol exhibits a substantial primary kinetic isotope effect (kH/kD = 5.83 at 298 K). The reaction has been studied in nineteen different organic solvents and the solvent effect has been analysed using Taft's and Swain's multiparametric equations. The temperature dependence of the kinetic isotope effect indicates the presence of a symmetrical transition state in the rate‑determining step. A suitable mechanism has been proposed.

 

IPC Code: Int. Cl7 C07B 33/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1224-1227

 

Mechanism of peroxide reactions : Kinetics of oxidation of sulfanilic acid by peroxomonosulfuric acid

Radhasyam Panda* & M Purna Ch. Reddy

 

The oxidation of sulfanilic acid by peroxomonosulfuric acid (PMSA) has been investigated in the pH range 0-12.5. The reaction obeys second order kinetics, first order each in [peroxomonosulfuric acid] and [sulfanilic acid] at constant pH. The observed bell–shaped pH–rate profile with a rate maximum at pH » 5.96 has been rationalised invoking various PMSA species and the unprotonated form of sulfanilic acid as the reactiing species, and their reactivities have been estimated. The mechanism of oxidation involves the nucleophillic attack of the nitrogen lone pair of unprotonated sulfanillic acid on the electrophilic peroxo–oxygen of PMSA species.

 

IPC Code: Int. Cl.7 C 07 B 33/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1228-1232

 

Phenol-amide chelates of cobalt(II), nickel(II), copper(II) and zinc(II) as catalysts for hydrolysis of active esters. Part IIa. Kinetics and mechanism of hydrolysis of
4-nitrophenylacetate by the metal(II) chelates of
1,2-bis(2-hydroxybenzamido)ethane and 1,3-bis(2-hydroxybenzamido)propane

Mahashweta Sahu, Guru C Pradhan, Prakash Mohanty & Anadi C Dash*

 

The hydrolysis of 4-nitrophenyl acetate (PNPA) has been studied using mononuclear chelates (ML) of cobalt(II), nickel(II), copper(II) and zinc(II) with 1,2-bis(2-hydroxybenzamido)-ethane(L1)  and 1,3-bis(2-hydroxybenzamido)-propane(L2) at 26.5 ± 0.2oC, I=0.5 mol dm-3, 8.1 £ pH £ 9.4 (tris buffer), 0.25 £ 103[ML]T/mol dm-3 £ 3.0.and 35.0% MeOH + water. The ionized species [M(L-H)]- (due to metal ion promoted amide deprotonation) are found to be reactive species for catalysis of PNPA  hydrolysis.

IPC Code: Int.Cl.7 C 07 B 41/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 12  

 

and nuclease activity of copper(II), nickel(II), cobalt(II) and iron(II) complexes with oxime-thiosemicarbazones

K Hussain Reddy*, M Surendra Babu, P Suresh Babu & S Dayananda

 

A novel ligand viz. 1-phenyl-1,2-propanedione-2-oxime thiosemicarbazone (PPDOT) has been synthesized and characterized. Complexes of copper(II), nickel(II), cobalt(II) and iron(II) with PPDOT have been synthesized and characterized by molar conductance, magnetic moments, electronic, IR and ESR spectroscopy. Electrochemical behaviour of these complexes is investigated by cyclic voltammetric studies. The nuclease activity of these complexes has been carried out on double stranded pBR 322 plasmid DNA by using gel electrophoresis experiments in absence and in the presence of oxidant (H2O2). Metal complexes of diacetylmonoxime thiosemicarbazone (DAMOT) are also investigated for better comparison

 

IPC Code: C01G 51/00; C01G 3/00; C01G 53/00; C01G 49/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp. 1239-1244

 

Heteroleptic tris-complexes of ruthenium(II/III) containing one bidentate Schiff base: Synthesis, characterisation and link-up of oxidation levels

Habibar Chowdhury, Doyel Bose, Rajarshi Ghosh, Sk Hafijur Rahaman &

Barindra Kumar Ghosh*

 

A series of mixed-tris chelates of ruthenium(II) and -(III) of general formula [RuL¢L2]z+ [L¢ = N-((pyridin-2-yl)formylidene)- aniline (pfan), N-((pyridin-2-yl)benzylidene)aniline (pban), N-((pyridin-2-yl)formylidene)benzylamine (pfba) or N-((pyridin-2-yl)benzylidene)benzylamine (pbba); L = 2,2¢-bipyridine (bpy), z = 2 or 3; L = 2-(m-tolylazo)pyridine (tap), z = 2] have been prepared, isolated as their perchlorates and characterised by physicochemical, magnetic and spectroscopic methods. The ruthenium(II) and rutheniun(III) complexes, respectively exhibit several MLCT and LMCT charge-transfer transitions in the 200-900 nm region. In MeCN solutions all the compounds exhibit ruthenium(III)-ruthenium(II) couple, and additionally bpy complexes show ruthenium(IV)-ruthenium(III) response. The stability of metal oxidation levels is discussed in terms of the electrochemical results and correlated to the p-acceptor properties of these ligands. On the negative side of SCE successive ligand reductions are observable involving diimine/azoimine group.

 

IPC Code: C 01 G 55/00; C 07 C 251/02

 

 

 

Indian Journal of Chemistry

Vol. 43A, June 2004, pp. 1245-1248

 

Synthesis and characterisation of iron(III) complexes of 1,2-dihydro-1-phenyl-2,3-dimethyl-4-[2¢,4¢-pentanedione-3¢- hydrazono]pyrazol-5-one

Reena Ravindran

 

A novel heterocyclic ligand, 1,2-dihydro-1-phenyl-2,3-dimethyl-4-[2¢,4¢-pentanedione-3¢-hydrazono]pyrazol-5-one, [AAPAAC], and its complexes with iron(III) in the presence of chloride, bromide, nitrate and perchlorate anions, have been synthesised and characterised using elemental analyses, conductance measurements, magnetic susceptibility and infrared, electronic and Mossbauer spectral studies. The ligand shows neutral bidentate and tridentate behaviour in the complexes. Spectral studies confirm an octahedral geometry around iron(III) in all the complexes.

IPC Code: C 01 G 49/00

 

 

 

Indian Journal of Chemistry

 Vol. 43A, June 2004, pp.1249-1252

 

Atomic absorption spectrometric determination of trace manganese after separation and preconcentration with
1-(2-pyridylazo)-2-naphthol-naphthalene adsorbent

Mohammad Ali Taher

 

An atomic absorption spectrometric method for the determination of trace amounts of manganese after adsorption of its 1-(2-pyridylazo)-2-naphthol complex on microcrystalline naphthalene has been developed. This complex is adsorbed on microcrystalline naphthalene in the pH range 8.9-10.2 from large volumes of aqueous solutions of various alloys and biological samples. After filtration, the solid mass consisting of the manganese complex and naphthalene is dissolved with 5 ml of dimethylformamide and the metal determined by flame atomic absorption spectrometry. Manganese can alternatively be quantitatively adsorbed on [1-(2-pyridylazo)-2-naphthol]-naphthalene adsorbent packed in a column and determined similarly. About 0.05 mg of manganese can be concentrated in a column from 500 ml of aqueous sample where its concentration is as low as 0.1 ng ml-1. Eight replicate determinations of 0.2 mg ml-1 of manganese gave a mean absorbance of 0.086 with a relative standard deviation of 1.6%. The sensitivity for 1% absorption was 11 ng ml-1. The interference of a large number of anions and cations has been studied and the optimized conditions developed were utilized for the trace determination of manganese in various standard samples.

 

IPC Code: G 01 J 3/42