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Indian Journal of Chemistry

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

 

 

VOLUME 42A

NUMBER 10

OCTOBER 2003

 

CONTENTS

Papers

 

2463

 

Optimization of regression model for predicting physicochemical properties of alkyl ethers

 

 

Minati Kuanar, Saroj K Kuanar, Sabita Patel & Bijay K Mishra*

 

 

 

A novel set of valence topological parameters have been derived for 28 alkyl ethers and they have been used for predicting boiling point, density and refractive index of these ethers by constructing regression models.

 

2470

 

In situ isothermal reduction of FeCl3 in the nanopores of SiO2 gel matrix

 

 

 

 

 

Dilip Kumar Mandal,, Aparajita Bose, Gopes Chandra Das &
Siddhartha Mukherjee*

 

 

 

 

 

 

2475

 

Co-precipitation of a mixture of CuO and Cr2O3 through NaNO3-KNO3 eutectic mixture and its catalytic activity

 

N B Singh* & A K Ojha     

 

 

A mixture of basic copper carbonate and chromium nitrate when heated at about 570 °C gives a mixture of CuO and Cr2O3. Basic copper carbonate and chromium nitrate when heated at »270 °C yields a mixture of the same oxides. The mixture of CuO and Cr2O3 obtained through the two routes is found to be an effective catalyst for the decomposition of ammonium perchlorate.

 

2480

 

Liquid phase benzylation of o-xylene over pillared clays

 

Manju Kurian & S Sugunan*

 

 

 

Iron, aluminium and mixed iron aluminium pillared clays have been prepared by partial hydrolysis method and doped with 10% Mo, V and Cr. They have been used as catalysts for benzylation of o-xylene. The results reveal that vanadia incorporated systems show maximum acidity, Fe pillared systems exhibit maximum activity and the presence of moisture has a diminishing effect on the rate.

 

 

2487

 

Synthesis and characterisation of manganese(III) heterochelates

 

 

Ismail A Patel, Pankaj Patel, S Goldsmith &  B T Thaker*

 

 

 

Notes

 

2493

 

Density functional study of some aliphatic semidione radical ions

 

Sonia Ralhan, Piyush K Shukla & N K Ray*

 

 

 

B3LYP density functional with 6-31G* basis set has been used to estimate ESR proton hyperfine coupling constants for a series of rigid semidione radical ions. The results of these calculations are in good agreement with the experimental results.

 

 

2496

 

Observation of multiple MLCT emissions for a CuIN4 chromophore in rigid matrices

 

 

 

 

 

Subhasis Panja , Sankar Chakravorti, Shubhamoy Chowdhury & Dipankar Datta*

 

 

 

 

 

 

2501

 

Aqueous solubility of benzene-hydrocarbon binary solute vapour mixture

 

 

 

 

A Guha* & Debaprasad Panda

 

 

 

Cavity formation energy  is calculated for water at 298.15K. The solubilities of seven benzene-hydrocarbon solute vapour mixtures in water have been determined with this cavity formation energy  . The result agrees well with the experimental values of solubilities.

 

2506

 

Solvation behaviour of Cu+ and Ag+ ions in acetonitrile-rich mixtures of benzene and ethanol. A viscometric study

 

M S Chau  M S Chauhan*, K Sharma & G Kumar

 

 

 

Viscocities of Bu4NClO4, Bu4NNO3, AgNO3 and CuClO4 have been determined in acetonitrile-rich mixtures of benzene and ethanol at 25oC. The data have been analyzed in terms of Jones-Dole viscosity A and B-coefficients.

 

  

 

2509

 

Solvent and electrode kinetic effects on anodic oxidation of Br-Br3-Br2 system on some bare and platinized electrode in some dipolar aprotic solvents from cyclic voltammetric measurements

 

 

 

 

 

J Datta*, C Bhattacharya, S Sinha & K K Kundu

 

 

 

Solvent and electrode kinetic effects on the anodic oxidation of Br-Br3-Br2 system involving Br/Br3 and Br3/Br2 redox couples, have been studied on bare, platinized Pt and C surfaces by cyclic voltammetric  measurements in acetonitrile, N,N–dimethylformamide and propylene carbonate and in water on bright Pt surface. The observed ks values for both the redox couples reflect that the electrocatalytic activities of the electrodes are in the order C < Pt £ (Pt) Pt < (C)Pt

 

 

2513

 

Density and viscosity of ternary liquid mixtures of squalane with (hexane+benzene), (cyclohexane+benzene) and (hexane+cyclohexane) at 298.15 K

 

S C Bhatia*, Neelima Tripathi &
 G Prakash Dubey

 

 

 

Densities  and viscosities for three ternary mixtures of squalane with (hexane+benzene), (cyclohexane+benzene) and (hexane+cyclohexane) have been measured over the entire composition range at 298.15 K and at atmospheric pressure. The results have been discussed in terms of interactions between the components of liquid mixtures, and the effects of size and shape of the components on excess properties.

 

 

2518

 

Reexamination of the reactivity of iron carbonyls with 1,2-ethanedithiol

 

 

 

 

 

S E Kabir*, A F M M Rahman, J Parvin & K M A Malik

 

 

 

 

 

2523

 

Studies on the copolymerisation of n-alkyl itaconates with styrene

 

 

 

 

Gulshan Kumar,  Saroj Aggarwal* & Veena Choudhary

 

 

 

 

 

2527

 

 

Micellar features and other solution properties of copper(II) soaps in benzene

 

 

M R K Sherwani, Rashmi Sharma*, Antima Gangwal  & Renu Bhutra

 

 

 

 

Copper soaps prepared from various vegetable oils like groundnut, mustard, sesame and soyabean have been analyzed for their micellar characteristics. The studies of various interactions suggest that solute-solvent interaction increases with the increase in content of shorter fatty acid in the composition of vegetable oil and lowering of molecular weight whereas solute-solute interaction decreases.

 

 

 

2531

 

Two pentacoordinate copper(II) complexes that display accessible Cu(III/II) couples

 

 

 

 

 

 

 

 

Michael G B Drew, Jnan P Naskar,
Shubhamoy Chowdhury & Dipankar Datta*

 

 

 

 

 

2536

 

Synthesis, biological and catalytic properties of Ru(II) benzamides Schiff base complexes

 

 

 

 

 

B S Jhaumeer-Laulloo & Minu G Bhowon*

 

 

 

 

 

 

 

2541

 

Thenoyltrifluoroacetone as a spectrophoto­metric reagent for determination of  ascorbic acid

 

Satya Prakash Arya* & Preeti Jain

 

 

 

An extractive spectrophotometric method for the determination of microamounts of ascorbic acid is described. The method is successfully used in the determination of ascorbic acid in pure vitamin C tablets, drops and multivitamin products.

 

 

Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2463-2469

 

 

Optimization of regression model for predicting physicochemical properties of alkyl ethers

 Minati Kuanar, Saroj K Kuanar, Sabita Patel & Bijay K Mishra*

 

A novel set of valence topological parameters have been derived for 28 alkyl ethers. Alongwith some connectivity and Wiener parameters, these parameters have been used for predicting boiling point (r = 0.996), density (r = 0.884) and refractive index (r = 0.978) of these ethers by constructing regression models. These models have been optimized by successive exclusion of variables.

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2470-2474

 

 

In situ isothermal reduction of FeCl3 in the nanopores of SiO2 gel matrix

Dilip Kumar Mandal, Aparajita Bose, Gopes Chandra Das & Siddhartha Mukherjee*

 

Intimately mixed FeCl3 and dextrose are distributed through out the nanometric pores of silica gel. The subsequent heat treatment in the temperature range 900 to 1000oC under nitrogen atmosphere leads to the reduction of FeCl3 to nanometric metallic iron by in situ hydrogen. The EPR analysis of the heat-treated samples shows the presence of metallic iron. The mechanism of in situ reduction kinetics of FeCl3 in silica gel is nucleation and growth type.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2475-2479

 

Co-precipitation of a mixture of CuO and Cr2O3 through NaNO3-KNO3 eutectic mixture and its catalytic activity

N B Singh & A K Ojha

 

When a mixture of basic copper carbonate and chromium nitrate in 1:1 molar ratio has been heated at about 570 °C a mixture of CuO and Cr2O3 is obtained. Further, when basic copper carbonate and chromium nitrate are mixed in 1:1 molar ratio in NaNO3-KNO3 eutectic mixture and heated at »270 °C i.e. at a much lower temperature, again a mixture of the same oxides has been obtained. The formation of the oxides is confirmed by powder X-ray diffraction technique. The mixture of CuO and Cr2O3 obtained through the two routes is found to be an effective catalyst for the decomposition of ammonium perchlorate.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2480-2486

 

Liquid phase benzylation of o-xylene over pillared clays

Manju Kurian & S Sugunan*

 

Iron, aluminium and mixed iron aluminium pillared clays have been prepared by partial hydrolysis method and doped with 10% Mo, V and Cr. The samples have been characterised by XRD, FTIR and surface area and pore volume measurements. The surface acid site distribution has been determined by temperature programmed desorption of ammonia. Vanadia incorporated systems show maximum acidity. Benzylation of o-xylene has been done as probe reaction to test catalytic activity. Benzyl chloride is a superior benzylating agent compared to benzyl alcohol in activity and selectivity. Cent percent selectivity towards monobenzylated product is obtained in all the cases. Fe pillared systems exhibit maximum activity. The catalytic activities of the systems can be correlated with the amount of strong acid sites. The effects of various reaction variables on the reaction have been studied. Presence of moisture has a diminishing effect on the reaction rate.

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2487-2492

 

Synthesis and characterisation of manganese(III) heterochelates#

Ismail A Patel, Pankaj Patel, S Goldsmith & B T Thaker*

 

Manganese(III) complexes of the type: (i) [Mn(Sal-o-phen)Bzp].2H2O, (ii) [Mn(Bzp-o-phen)Sal].2H2O, (iii) [Mn(Acp-en) 1, 10 phen]ClO4 and (iv) [Mn(Acp-en) 2, 2¢ dipy]ClO4 (where, Sal-o-phen and Bzp-o-phen are the Schiff bases derived from salicylaldehyde and 1-phenyl-3-methyl-4-benzoyl-2-pyrazoline-5-one and o-phenylenediamine respectively; Acp-ethylene is a Schiff base derived from 1-phenyl-3-methyl-4-acetyl-2-pyrazoline-5-one and ethylenediamine; 1, 10 phen = 1, 10 phenanthroline and 2, 2¢ dipy = 2, 2¢ dipyridyl) have been prepared and their physico-chemical properties studied. The former two complexes are non-electrolytes and the later two are 1:1 electrolytes in solution. Magnetic moment values close to 4.9 B.M. indicate the presence of Mn(III) complexes with four unpaired electrons and lack of any kind of exchange interaction. On the basis of analytical and physical data a tetragonally distorted octahedral structure is suggested for all of the complexes. The complexes were treated for TGA and DTA studies. From the TGA curves, thermo-kinetic parameters such as activation energy (E), order of reaction (n), pre-exponential factor (A) and entropy change (DS) have been calculated using different methods suggested by Horowitz-Metzger, Freeman-Carroll, Coats-Redfern and Sharp-Wentworth.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2493-2495

 

 

Density functional study of some
aliphatic semidione radical ions

 Sonia Ralhan, Piyush K Shukla & N K Ray*

 

B3LYP density functional with 6-31G* basis set has been used to estimate ESR proton hyperfine coupling constants for a series of rigid semidione radical ions. The calculated estimates are in excellent agreement with experimental results. Single- point UB3LYP calculations have also been made using UHF/3-21G and UAM2 optimized geometries. Interestingly, the results of these computationally cheaper calculations are also in good agreement with the experimental results.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2496-2500

 

Observation of multiple MLCT emissions for a CuIN4 chromophore in rigid matrices

Subhasis Panja , Sankar Chakravorti, Shubhamoy Chowdhury & Dipankar Datta*

 

 [CuL2]ClO4 (1), where L is a 1:2 condensate of ethylenediamine and benzophenone, displays four MLCT emissions with maxima lem = 617, 583, 549 and 494 nm in poly(methyl methacrylate) matrix at room temperature. Three of these emissions are observed for 1 in methanol glass at 77 K with lem = 473, 440 and 412 nm. The origins of these emissions are investigated by Extended Hückel calculations on [CuL2]+ at the crystallographically determined geometry.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2501-2505

 

 

Aqueous solubility of benzene-hydrocarbon binary solute vapor mixture

 A Guha* & Debaprasad Panda

 

Cavity formation energy (CFE) which is equivalent to the free energy cast of insertion of a hard sphere solute in a hard sphere solvent is calculated for water at 298.15K. The solubilities of seven benzene-hydrocarbon solute vapor mixtures in water has been determined with this CFE. The result agrees well with the experimental values of solubilities. The method has also been used to calculate physico-chemical properties of solvent and solute molecules. The calculation shows the importance of cavity formation energy in determining the solubility and other physico-chemical properties.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2506-2508

 

 

Solvation behaviour of Cu+ and Ag+ ions in acetonitrile-rich mixtures of benzene and ethanol. A viscometric study

M S Chauhan*, K Sharma & G Kumar

 

Viscocities of Bu4NClO4, Bu4NNO3, AgNO3 and CuClO4 have been determined in acetonitrile-rich mixtures of benzene and ethanol at 25oC. The data have been analyzed in terms of Jones-Dole viscosity A and B-coefficients. Ionic contributions B± values were obtained on the basis of Bu4NBPh4 assumption. Effective ionic radii (Ri) of ClO4-, NO3-, Cu+ and Ag+ have been calculated from the relation: B± = 2.5 (4¤3)p Ri3 N/3000. An examination of Ri values as a function of solvent composition suggests the existence of specific ion-solvent interactions in the case of Cu+ and Ag+ ions. A contribution due to hydrogen bond formation is however observed in acetonitrile-ethanol mixture in case of ClO4- and NO3- anions. A reasonably good agreement in respect of Ri values of all ions with those obtained earlier from conductance measurements is attributed to the fact that the solvated ionic species exist as rigid spherical entities during the viscous flow process.

 

 

 

 

 

 

Indian Journal of Chemistry 

Vol. 42A, October 2003, pp. 2509-2512

 

 

Solvent and electrode kinetic effects on
anodic oxidation of Br-Br3-Br2 system on some bare and platinized electrode in some dipolar aprotic solvents from cyclic voltammetric measurements

 J Datta*, C Bhattacharya, S Sinha & K K Kundu

 

Solvent and electrode kinetic effects on the anodic oxidation of Br-Br3-Br2 system involving Br/Br3 and Br3/Br2 redox couples, have been studied on bare and platinized Pt and C surfaces by cyclic voltammetric (CV) measurements in some dipolar aportic solvents like acetonitrile, N,N–dimethylformamide and propylene carbonate and in water on bright Pt surface. The rate constants (ks) have been evaluated by Shain and Nicholson’s formulations as appropriate to the irreversible and quasi-reversible CV waves observed in different cases. Kinetic solvent effects on both the redox reactions on Pt surface in different solvents have been analyzed in the light of initial and transition state (TS) solvation using the previously determined solvation free energies of Br, Br3 and Br2 in the respective solvents. The observed ks values for both the redox couples reflect that the electrocatalytic activities of the electrodes are in the order C < Pt £ (Pt) Pt < (C)Pt, as are expected from the combined effects of geometric and electronic characters of the involved electrode surfaces.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2513-2517

 

 

Density and viscosity of ternary liquid mixtures of squalane with (hexane+benzene), (cyclohexane+benzene) and (hexane+cyclohexane) at 298.15 K

S C Bhatia*, Neelima Tripathi & G Prakash Dubey

 

Densities (r) and viscosities (h) for three ternary mixtures of squalane with (hexane+benzene), (cyclohexane+benzene) and (hexane+cyclohexane) have been measured over the entire composition range at 298.15 K and at atmospheric pressure. The excess molar volumes,  and viscosity deviations, dh have been calculated from experimental measurements. The results have been discussed in terms of interactions between the components of liquid mixtures, and the effects of size and shape of the components on excess properties.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2518-2522

 

 

Reexamination of the reactivity of iron carbonyls with
1,2-ethanedithiol

S E Kabir*, A F M M Rahman, J Parvin & K M A Malik

 

The reactions of 1,2-ethanedithiol with [Fe3(CO)12], Na2[Fe(CO)4], Na2[Fe2(CO)8] and Fe(CO)5 afforded the previously reported dinuclear compound [Fe2(CO)6(µ-SCH2CH2S)] 1. The reactions of Na2[Fe(CO)4] with 1,2- ethanedithiol in presence of [Cp2TiCl2] both at room temperature and at 68oC also gave 1. Treatment of [CpFe(CO)2]2 with 1,2- ethanedithiol at 110oC yielded 1a, which is cocrystallized with ferrocene (2:1 ratio), formed from the same reaction. Spectroscopic data and single crystal X-ray diffraction studies of 1a are reported.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2523-2526

 

 

Studies on the copolymerisation of n-alkyl itaconates
with styrene

Gulshan Kumar, Saroj Aggarwal* & Veena Choudhary

 

The synthesis and characterization of n-hexyl itaconate (HI) and n-octyl itaconate (OI) monomers and their homopolymeri­sation and copolymerisation with styrene in bulk using azobisiso­butyronitrile (AIBN) as an initiator have been reported. Copolymer composition has been determined from 1H-NMR by taking the ratio of intensities of signals due to -OCH2 protons of itaconates (δ =3.9 ppm) and aromatic protons of styrene (δ =6.8-7.2 ppm). The intensity of signal due to -OCH2 proton increases with increasing mole fraction of itaconate monomers in the feed. The reactivity ratios are found to be r1 = 1.2 (styrene), r2 = 0.75 (HI) and r1 = 1.38 (styrene), r2 = 0.62 (OI). All the samples have high moleculer weight, i.e., Mn in the range of 40 ×103 to 62 ×103 and Mw in the range of 43 ×103 to 113 ×103 with polydispersity index in the range of 1.64 - 1.85. Intrinsic viscosity [h] of the copolymers decreases with increasing amount of itaconate in the copolymers. Inspite of having very high molecular weight (77,000-78,000) the homopolymers (PHI, POI) have a very low value of [h] (4±0.5 ml/g). These low values of [h] may be due to the presence of long branches in itaconates showing comb type structure. Thermal studies of the copolymers show all the samples to be stable up to 300oC.

 

 

 

  

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2527-2530

 

 

Micellar features and other solution properties of
copper(II) soaps in benzene

M R K Sherwani , Rashmi Sharma*, Antima Gangwal    & Renu Bhutra

 

Copper soaps prepared from various vegetable oils have been analyzed for their micellar characteristics. Density of copper surfactants of groundnut, mustard, sesame and soyabean oils in benzene has been measured and using density data, molar volume and apparent molar volume have been evaluated. These parameters show a change at cmc suggesting the micellar behaviour of the soaps. The critical micelle concentration are found to decrease with increase in average molecular weight of the soap. The apparent molar volume has been examined in terms of Masson equation. The limiting apparent molar volume (фvo) has been interpreted in terms of solute-solvent interaction while limiting slope (sv) in terms of solute-solute interaction. The studies of various interactions suggest that solute-solvent interaction increases with the increase in content of shorter fatty acid in the composition of vegetable oil and lowering of molecular weight whereas solute-solute interaction decreases.

 

 

 

 

Indian Journal of Chemistry

 Vol. 42A, October 2003, pp. 2531-2535

 

 

Two pentacoordinate copper(II) complexes that display accessible Cu(III/II) couples

 Michael G B Drew, Jnan P Naskar, Shubhamoy Chowdhury & Dipankar Datta*

 

Two copper(II) complexes of the type CuL2.imidazole (1) and Cu2L4(4,4¢-bpy).2H2O.C6H14 (2), where LH = 1-nitroso-2-naphthol and 4,4¢-bpy = 4,4¢-bipyridine, are characterised by X-ray crystallography. In 2, the two copper atoms are linked by 4,4¢-bpy. In both the complexes, copper is found to have a distorted square pyramidal N3O2 coordination sphere. The axial position in 1 is occupied by an oxygen atom while those in 2 by the nitrogen atoms of 4,4¢-bpy. The two complexes display quasireversible Cu(III/II) couples around 0.68 V vs. saturated calomel electrode in cyclic voltammetry in dichloromethane.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2536-2540

 

Synthesis, biological and catalytic properties of Ru(II) benzamides Schiff base complexes

B S Jhaumeer-Laulloo & Minu G Bhowon*

 

A few Schiff bases (p-chlorobenzaldehyde)-benzylimine 1, (salicylaldehyde)-p-toluidiimine 2, bis(p-anisaldehyde)-ethylenediimine 3, bis(1-naphthaldehyde)-p-phenylenediimine 4, bis(m-nitrobenzaldehyde)-p-phenylenediimine 5, and bis(salicylaldehyde)-o-phenylenediimine 6 have been synthesized and reacted with Ru2Cl2(DNBH)(H2O)4 (TR1) to yield six binuclear ruthenium complexes 1a-6a. All the complexes are characterized by spectroscopic, elemental and magnetic susceptibility data. The coordination is found to be through carbonyl oxygen of amide, phenolic oxygen and azomethine nitrogen of the Schiff bases in the octahedral environment of the metal. All the metal complexes show antibacterial and catalytic activity.

 

 

 

 

Indian Journal of Chemistry

Vol. 42A, October 2003, pp. 2541-2544

 

Thenoyltrifluoroacetone as a spectrophoto­metric reagent for determination of ascorbic acid

Satya Prakash Arya* & Preeti Jain

 

An extractive spectrophotometric method for the determination of microamounts of ascorbic acid is described. 1-[Thenoyl- (2¢)-3,3,3-trifluoro-acetone] (HTTA) is found to react with iron (III) in strongly acidic medium giving a red coloured complex. The method is based on the proportionate decrease in the colour intensity of Fe(III)-HTTA complex with the addition of ascorbic acid at 405 nm. Linear calibration curve is observed in the range 1.0-5.0 mg/mL of ascorbic acid. The molar absorptivity and Sandell’s sensitivity are 5.3´104 L/mol/cm and 0.003µg/cm2, respectively. The interference of sugars, vitamins, amino acids, mineral salts, sweetening agents etc. has been studied. The method is successfully used in the determination of ascorbic acid in pure vitamin C tablets, drops and multivitamin products.