Indian Journal of Chemistry

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


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VOLUME 45A

NUMBER 4

April 2006

CONTENTS

Papers

 

839

 

Template synthesis and characterization of well-aligned carbon nanotubes by carbonization of polyparaphenylene

 

 

 

 

 

 

 

 

T Maiyalagan & B Viswanathan*

 

 

 

 

Well-aligned carbon nanotubes have been synthesized by pyrolysis of polyparaphenylene on alumina membrane template. Scanning electron micrographs and transmission electron micrographs reveal the hollow structure and vertically aligned features of the nanotubes. Raman spectrum shows characteristic bands at 1384 cm-1
(D-band) and 1603 cm-1 (G–band) indicating well-graphitized nanotubes. The electrochemical behavior of the synthesized carbon nanotube film coated with glassy carbon electrode shows fast electron transfer and higher current response.

 

 

845

 

Hetero-hexanuclear ruthenium-nickel complexes containing 2,2-biimidazolate dianion. Synthesis, ESI-MS and X-ray structure characterization

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sudipta Chatterjee, Kunal K Kamar,
Michael B Hursthouse, Mark E Light
& Sreebrata Goswami*

 

 

 

 

 

 

853

 

Mono- and di-nuclear Cu(II) complexes of
p-tert-butyl-calix[4]arene-1,3-diacid derivative:
A comparative study of their characterization and catecholase mimetic activity

 

 

 

 

 

 

Amjad Ali, Sunita Salunke-Gawali,
Chebrolu P Rao* & Jorge Linares

 

 

 

 

Mono- and di-nuclear Cu(II) complexes of p-tert-butyl-calix[4]arene-1,3-diacid exhibit characteristic differences.  The dinuclear complex exhibits different characteristics in its EPR and magnetic studies and shows higher catecholase mimetic activity over its mononuclear counterpart due to its Cu2O2 core.

 

 

858

 

Synthesis, spectroscopic and crystallographic studies on two copper(II) benzimidazole complexes: Supramolecular frameworks built from N–H…O, N–H…Cl and O–H…Cl hydrogen bonds

 

 

 

 

Md. Mijanuddin, Sumana Gangopadhyay*, Swastik Mondal, Monika Mukherjee & Mahammad Ali*

 

 

 

 

 

 

864

 

New hydrazinium complexes of lanthanide(III) with ethylenediaminetetraacetate: Spectral, thermal and XRD studies

 

 

 

 

 

L Vikram & B N Sivasankar*

 

 

 

 

Dihydrazinium dihydrogen ethylenediaminetetraacetate reacts with trivalent lanthanide ions to yield nine-coordinated hydrazinium lanthanum ethylenediamine-tetraacetate hydrates.

 

2(N2H5)2 H2EDTA  +  Ln(NO3)3(H2O)x   +  yH2O

N2H5 [Ln(EDTA)(H2O)3](H2O)5  +  H4EDTA
+  3N2H4.H2O  +  3HNO3  +  (x + y -11)H2O

 

872

 

Synthesis and electrochemical investigations on
2 - phenyl - 4 - [4' -(3''-ethoxy)phenylazophenyl]-
3 - thioxo - 3, 4 - dihydro - 2H, 2, 4, 9, 10 -tetraazaphenanthrene-1-one

 

 

 

 

Pratibha Sharma*, Ashok Kumar &
Manisha Sharma

 

 

 

 

A new facile method for the synthesis of 2-phenyl-4-[4'-(3''-ethoxy)phenylazophenyl]-3-thioxo-3,4-dihydro-2H, 2,- 4, 9 ,10 - tetraazaphenanthrene-1-one has been developed. The electrochemical reduction of this compound takes place in a single, two-electron transfer, diffusion- controlled, with an irreversible wave in the pH range 2.0-12.0 at dropping mercury and glassy carbon electrodes. A plausible reduction mechanism is suggested on the basis of cyclic voltammetric, polarographic and coulometric studies.

 

 

877

 

Kinetic and mechanistic studies on
the interaction of 2-aminopyrimidine
with dichloro[1 – alkyl – 2 - (arylazo)imidazole] - palladium(II) complexes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sushanta Saha, Tapas Majumdar &
Ambikesh Mahapatra*

 

 

 

 

 

 

882

 

Oxidation of nonionic surfactant (Tween-80) by chromium(VI) in acidic medium

 

 

 

 

 

 

 

Syed Misbah Zahoor Andrabi, Zaheer Khan* & Kabir-ud-Din

 

 

 

 

The oxidation of Tween-80 by chromium(VI) in aqueous acidic solutions has been studied at different temperatures. The rate of disappearance of chromium(VI) follows second order kinetics; first order each in [Cr(VI)] and
[Tw-80] at constant acidity. The reaction order with respect to [H+] increases from one to higher with increase in [HClO4]. The reaction is considered to proceed through the formation of a chromate ester between chromium(VI) and the primary –OH group of polyoxyethylene chain of Tw-80.

 

Notes

 

887

 

Density functional study of 1,3-hydrogen shifts in 2,4-pyronone

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Piyush K Shukla, A Singh, S K Mishra &
N K Ray*

 

 

 

 

 

891

 

Composition-dependent dynamical structures of binary mixtures of mono alkyl ethers of ethylene glycol with some polar solvents determined by microwave dielectric relaxation measurements

 

 

 

 

 

R J Sengwa*, Madhvi, Sonu Sankhla &
S
hobha Sharma

 

 

 

 

Concentration dependent values of dielectric constant and relaxation time of ethers-Gly mixtures indicate a strong H-bond heterogeneous interaction between the hydroxyl group/s of the molecules. These interactions significantly facilitate the molecular dynamics in the binary mixtures as compared to the dynamics of pure Gly molecules.

897

 

PtIV inhibition on the rate of chloramine-T oxidation of α-amino acids in alkaline medium

 

 

 

 

 

 

 

 

 

Rashmi Tripathi & Santosh K Upadhyay*

 

 

 

 

An inhibitory effect of platinum(IV) on the rate of oxidation of α-amino acids (alanine, phenylalanine and valine) by alkaline chloramine-T has been observed.

 

CAT + H2O        K1      RNHCl + OH-    fast          (i)

RNHCl + AA         k2             X             fast          (ii)

RNHCl + X            k3             product   slow        (iii)

RNHCl + PtIV         K4             Y             fast          (iv)

 

 

901

 

Kinetics and reactivity of indole-2, 3-dione ring towards alkali in dimethyl sulphoxide-water mixtures

 

 

 

 

 

 

 

 

 

 

Magda F Fathalla & Amel M Ismail*

 

 

 

 

 

905

 

A study on interaction between benzyl alcohol and cationic surfactant micelles by 1H NMR

 

 

 

 

 

 

 

Xi-Lian Wei, Bao-Lin Yin, Ji-Chun Cui,Jie Liu & De-Zhi Sun*

 

 

 

 

Solubilization of benzyl alcohol in aqueous micellar solution of 3-alkoxy-2-hydroxypropyl trimethyl ammonium bromides has been studied by high resolution 1H NMR. Results indicate that longer the hydrophobic chain of CnNBr, stronger is the tendency of benzyl alcohol to transfer from D2O to micelle phase and easier is the solubilization of benzyl alcohol in micellar solution.

 

 

909

 

Catechol (1,2-dihydroxybenzene) inside charged film on electrode surface – A new voltammetric sensor for vitamin C

 

 

 

 

 

 

 

 

 

 

 

 

Rimki Bhattacharjya & Diganta Kumar Das*

 

 

 

 

 

 

913

 

Spectrophotometric determination of hydroxylamine and its derivatives in drug formulations by the indophenol reaction

 

 

 

 

 

 

B Deepa, K S Nagaraja* & N Balasubramanian

 

 

 

 

Hydroxylamine has been determined by its reduction to ammonium sulphate in Zn/H2SO4 column and Berthelot reaction of the formed ammonium sulphate using salicylic acid, sodium hypochlorite and sodium nitroprusside to give indophenol blue. The molar absorptivity is found to be 1.9x104 l mol-1cm-1. Beer’s law is obeyed in the range 2.5 - 25 mg of hydroxylamine in 10 ml of its solution. The developed method has been applied for the determination of hydroxylamine and its derivatives after hydrolysis in drug formulations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Authors for correspondence are indicated by (*)

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 839-844

Template synthesis and characterization of well-aligned carbon nanotubes by carbonization of polyparaphenylene

T Maiyalagan & B Viswanathan*

Received 18 January 2005; revised 20 February 2006

The synthesis of well-aligned carbon nanotubes by pyrolysis of polyparaphenylene on alumina membrane template is described here. The prepared nanotubes have been characterized by electron microscopic analyses, Raman spectroscopy and cyclic voltammetry. Scanning electron micrographs and transmission electron micrographs reveal the hollow structure and vertically aligned features of the nanotubes. The surface morphology of the nanotubes has been studied by atomic force microscopy. Raman spectrum shows characteristic bands at 1384 cm-1 (D-band) and 1603 cm-1 (G–band) indicating well-graphitized nanotubes. The electrochemical behavior of the synthesized carbon nanotube film coated with glassy carbon electrode shows fast electron transfer and higher current response. The well-aligned carbon nanotube arrays can have potential applications in lithium-ion battery and other fields.

IPC Code: Int. Cl.8 B82B; C01B31/02

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 845-852

Hetero-hexanuclear ruthenium-nickel complexes containing 2,2¢-biimidazolate dianion. Synthesis, ESI-MS and X-ray structure characterization

Sudipta Chatterjee, Kunal K Kamar, Michael B Hursthouse, Mark E Light & Sreebrata Goswami*

Received 29 September 2005; revised 20 February 2006

Efficient and direct synthesis of hexametallic complexes, [{(pap)2Ru(biim)}4M2](ClO4)4 (pap = 2-(phenylazo) pyridine, M = Ni [2a] and Cu [2b]) based on the reaction of hydrated MCl2 and [{(pap)2Ru(biim)}2Ag2](ClO4)2 is elaborated. Synthesis of the 2,2´-bipyridine (bpy) analogue of [2a] is also described. Electrospray mass spectra of the complexes are analyzed which fully corroborate with their formulations. X-ray structure of a representative complex [{(bpy)2Ru(biim)2}4Ni2](ClO4)4, [3a] is reported. The structure consists of four octahedral [(bpy)2Ru(biim)] units arranged around the Ni2-moiety in a propeller type arrangement. The separation between the two nickel (II) ions in this complex is 2.803(7) Å. The dependence of network topology on counteranions is also reported, which ultimately gives rise to a 2D sheet structure. The two nickel complexes [2a] and [3a] are diamagnetic and display resolved 1H NMR spectra in dmso-d6. These are intensely coloured and their visible range spectra are dominated by an intense transition (e, 37,000-38,000 M-1 cm-1) due to Ru dπ→π* (ligand) transition. These complexes display multiple cyclic voltammetric responses, of which the responses at anodic potentials are ascribed to oxidations of the ruthenium centres.

IPC Code: Int. Cl.8 C07F15/00

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 853-857

 

Mono- and di-nuclear Cu(II) complexes of p-tert-butyl-calix[4]arene-1,3-diacid derivative: A comparative study of their characterization and
catecholase mimetic activity

Amjad Ali, Sunita Salunke-Gawali, Chebrolu P Rao* & Jorge Linares

Received 22 September 2005; revised 14 February 2006

Reaction of copper(II) perchlorate with p-tert-butyl-calix[4]arene-1,3-diacid gives mono-nuclear complex in acetonitrile and dinuclear complex in methanol which have been isolated as their pyridine bound adducts. The dinuclear complex exhibits different characteristics in its EPR and magnetic studies. The reactivity studies clearly indicate that the dinuclear complex has higher catecholase mimetic activity over its mononuclear counterpart owing to its coordination favourability.

IPC Code: Int. Cl.8 C07F1/08

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 858-863

Synthesis, spectroscopic and crystallographic studies on two copper(II)
benzimidazole complexes: Supramolecular frameworks built from
N–H…O, N–H…Cl and O–H…Cl hydrogen bonds

Md. Mijanuddin, Sumana Gangopadhyay*, Swastik Mondal, Monika Mukherjee & Mahammad Ali*

Received 31 May 2005; revised 30 January 2006

The tridentate ligands 2,6-bis(benzimidazole-2′-yl)pyridine (L1) and N,N-bis(benzimidazole-2′-yl-methyl)amine (L2) with N3 donor set form the corresponding mononuclear [Cu(L1)(ClO4)(Cl)].H2O] (1) and [Cu(L2)(Cl2)].H2O (2) complexes, which have been characterized by elemental analysis, UV-Vis spectra, IR, EPR and magnetic moment studies. Single crystal X-ray structure studies for both the complexes show that coordination geometries around the copper centre are best described as distorted square pyramidal with three nitrogen atoms of tridentate ligand and a chloride ion defining the equatorial planes. The apical positions in the complexes are occupied by a perchlorate O atom in 1 and a chloride ion in 2. Metal directed assembly of infinite two-dimensional supramolecular network stabilizes the crystal structures of both complexes in the solid state. The global magnetic interactions in complexes 1 and 2 are found to be paramagnetic with meff values of 1.65 BM and 1.63 BM, respectively, which are typical for a Cu(II) d9 system.

IPC Code: Int. Cl.8  C07F1/08

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 864-871

 

New hydrazinium complexes of lanthanide (III) with ethylenediaminetetraacetate: Spectral, thermal and XRD studies

 

L Vikram & B N Sivasankar*

Received 22 November 2005; revised 23 January 2006

             Diammonium and dihydrazinium salts of ethylenediaminetetraacetic acid have been prepared by neutralization reaction between ammonia or hydrazine hydrate and H4EDTA in 2:1 ratio. Ammonium hydrazinium salt has also been prepared using a mixture of the two bases and the salts have been characterized by chemical analyses, elemental analyses, infrared spectra and thermal studies.   Dihydrazinium salt, (N2H5)2H2EDTA has been used as a ligand to prepare hydrazinium lanthanum EDTA hydrates, N2H5[Ln(EDTA)(H2O)3](H2O)5 (where Ln= La, Ce, Pr, Nd, Sm). These complexes have been characterized by chemical and elemental analyses, conductivity and magnetic moment measurements and electronic and infrared spectral studies. TG and DTA traces indicate that these complexes undergo multi-step degradation to yield respective oxides and Ln2O3 as the final residue. The metal analyses, infrared spectra and X-ray powder techniques have been used to confirm the end product.

IPC Code: Int. Cl.8 C07F5/00

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 872-876

Synthesis and electrochemical investigations on 2-phenyl-4-[4´-(3´´-ethoxy)-phenylazophenyl]-3-thioxo-3,4-dihydro-2H,2,4,9,10-tetraazaphenanthrene-1-one

Pratibha Sharma*, Ashok Kumar & Manisha Sharma

Received 12 August 2004; revised 26 January 2006

A new facile method for the synthesis of 2-phenyl-4-[4´-(3´´-ethoxy)phenylazophenyl]-3-thioxo-3,4-dihydro-2H,2,4,9,10-tetraazaphenanthrene-1-one has been developed. The electrochemical reduction of this compound takes place in a single, two-electron transfer, diffusion-controlled, irreversible wave in the pH range 2.0-12.0 at dropping mercury and glassy carbon electrodes. A plausible reduction mechanism is suggested on the basis of cyclic voltammetric, polarographic and coulometric studies. Kinetic parameters, i.e., charge transfer coefficient (an) and forward rate constant (K0f,h) have also been calculated.

IPC Code: Int.Cl.8  G01R

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 877-881

Kinetic and mechanistic studies on the interaction of 2-aminopyrimidine with dichloro[1-alkyl-2-(arylazo)imidazole]palladium (II) complexes

Sushanta Saha, Tapas Majumdar & Ambikesh Mahapatra*

Received 24 August 2005; revised 16 February 2006

Nucleophilic substitution of Pd(RaaiR/)Cl2 [(RaaiR/=1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N=N-C3H2NN-1-R/; where R = H(a)/Me(b)/Cl(c) and R/ = Et(1)/Bz(2)] with 2-aminopyrimidine (2-NH2-Pym) in MeCN at 303 K, to form [Pd2(2-NH2-Pym)2Cl4], has been studied spectrophotometrically under pseudo-first-order conditions. The results obtained support a nucleophilic association path. The reaction follows the rate law, Rate = {k0 + k [2-NH2-Pym]0}[Pd(RaaiR/)Cl2], first order each in Pd(RaaiR/)Cl2 and 2-NH2-Pym. The rate increases as follows: Pd(RaaiEt)Cl2 < Pd(RaaiBz)Cl2 and Pd(MeaaiR/)Cl2 < Pd(HaaiR/)Cl2 < Pd(ClaaiR/)Cl2. External addition of Cl- (LiCl) suppresses the rate inversely. The reactions have been studied at different temperatures (298-313 K) and activation parameters, DH° and DS° of the reactions have been calculated from the Eyring plot. The data support the proposed mechanism.

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 882-886

Oxidation of nonionic surfactant (Tween-80) by chromium(VI) in acidic medium

Syed Misbah Zahoor Andrabi & Zaheer Khan*, Kabir-ud-Din

Received 31 January 2005; revised 13 February 2006

The oxidation of Tween-80 by chromium(VI) in aqueous acidic solutions has been studied at different temperatures (30-60 °C). The rates of disappearance of chromium(VI) absorbance follow second order kinetics; first order each in [Cr(VI)] and [Tw-80] at constant acidity. The reaction order with respect to [H+] increases from one to higher with increase in [HClO4]. Interestingly, Tw-80 is not oxidised in absence of acid. The reaction is considered to proceed through the formation of a chromate ester between the chromium(VI) and primary –OH group of polyoxyethylene chain of Tw-80. The activation parameters calculated using Arrhenius and Eyring equations are: Ea = 46 kJ mol–1, ΔH# = 44 kJ mol–1 and
ΔS# = – 200 JK–1 mol–1. A mechanism consistent with the results obtained has been proposed with the following rate equation:

 (k1Kes1Ka1[H+] + k2Kes2Ka2 Ka1[H+]2) [Tw-80]

d[CrVI]/dt =

(1+Ka1[H+] + Ka1Ka2[H+]2)

IPC Code: Int. Cl.8 C07B33/00

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 887-890

 

Density functional study of 1,3-hydrogen shifts in 2,4-pyronone

Piyush K Shukla, A Singh, S K Mishra & N K Ray*

Received 27 July 2005; revised 14 February 2006

Density functional calculations have been performed to study 1,3 hydrogen shifts in 2,4-pyronone. In pyronone, two
1,3-hydrogen shift reaction paths are possible. Path I leads to the formation of 4-hydroxy-a-pyrone and Path II gives 2-hydroxy-g-pyrone. Diketo form is found to be the most stable form followed by 4-hydroxy-a-pyrone and 2-hydroxy-g-pyrone. Activation energy for Path I is lower than that for Path II. Both the reactions are predicted to be endothermic. Inclusion of electron correlation lowers the energy barrier and makes the reaction less endothermic. Variation of descriptors like chemical hardness and electrophilicity along the two different pathways has also been investigated. Effect of solvent on barrier heights has also been examined. Effect of different substituents (fluoro, methyl and phenyl) at position 6 of pyronone has also been studied.

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 891-896

 

Composition–dependent dynamical structures of binary mixtures of mono alkyl ethers of ethylene glycol with some polar solvents determined by microwave dielectric relaxation measurements

R J Sengwa*, Madhvi, Sonu Sankhla & Shobha Sharma

Received 12 September 2005; revised 10 February 2006

The formation of H-bond heterogeneous structures and their dynamics in the binary mixtures of the homologous series of mono alkyl ethers of ethylene glycol with glycerol (Gly), dimethyl sulphoxide (DMSO) and dimethyl formamide (DMF) have been investigated from dielectric constant and microwave dielectric relaxation measurements at 25°C using Time Domain Reflectometry technique. The concentration dependent values of dielectric constant and relaxation time of ethers–Gly mixtures indicate a strong H-bond heterogeneous interaction between the hydroxyl group/s of the molecules, and these interactions significantly facilitate the molecular dynamics in the binary mixtures as compared to the dynamics of pure Gly molecules. The dielectric relaxation values of ethers–DMSO and ethers–DMF mixtures also confirm the complex formation in these systems over the entire concentration range. Further, the effect of molecular size of the ether molecules on the nature of heterogeneous interaction with different polar solvents and hindrance to the molecular dynamics in the binary mixtures has been recognized from the comparative values of measured dielectric parameters.

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 897-900

PtIV inhibition on the rate of chloramine-T oxidation of α-amino acids in
alkaline medium

Rashmi Tripathi & Santosh K Upadhyay*

Received 17 November 2005; revised 14 February 2006

An inhibition effect of platinum(IV) on the rate of oxidation of α-amino acids (alanine, phenylalanine and valine) by alkaline chloramine-T (CAT) has been observed. The kinetic results may be represented by the following rate law,

 

                d[CAT]               2k[CAT]T [AA]

         __     ____________    =   ___________________________

                    dt                  K[AA] +K’’ [PtIV]

 

where AA represents α-amino acid and k, K and K’’ represent constants.

IPC Code: Int. Cl.8  CO7B33/00

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp.901-904

Kinetics and reactivity of indole-2,3-dione ring towards alkali in dimethyl sulphoxide-water mixtures

Magda F Fathalla & Amel M Ismail*

Received 24 May 2005; revised 24 January 2006

Kinetics of alkaline hydrolysis of indole-2,3-dione (isatin) and indole-2,3-dione (N-methyl isatin) have been carried out at different percentages of DMSO-H2O mixtures and at different temperatures in the range 30-45°C. The reaction proceeds according to pesudo first-order kinetics. The presence of an electron releasing substituent methyl group attached to nitrogen atom accelerates the reaction rate. Thermodynamic activation parameters DH#, DS# and DG# have been determined. The negative values of entropy of activation and the non-linear relation between log rate constant and reciprocal of dielectric constant suggest selective solvation by the higher polar water solvent molecules.

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 905-908

A study on interaction between benzyl alcohol and cationic surfactant micelles by 1H NMR

Xi-Lian Wei, Bao-Lin Yin, Ji-Chun Cui, Jie Liu & De-Zhi Sun*

Received 18 April 2005; revised 20 February 2006

Solubilization of benzyl alcohol in aqueous micellar solution of 3-alkoxy-2-hydroxypropyl trimethyl ammonium bromides (CnH2n+1OCH2CH(OH)CH2N(CH3)3+ Br-, abbreviated as CnNBr, (n=8, 12, 14, 16) has been studied by high resolution 1H NMR. Results indicate that the alkyl chain length of the surfactant affects the solubility of benzyl alcohol in the micellar solution. The peak of methylenes in long chain surfactant splits into an upfield signal and a downfield signal when the solubilization system is at high molar ratio of benzyl alcohol to sufactant. The solubility of benzyl alcohol in micelle solutions of different surfactants (n=8, 12, 14, and 16) at the same concentration (3.00×10-2mol·L-1) are 0.1125, 0.1470, 0.1755 and 0.2100 mol L-1, respectively. The transfer free energy of benzyl alcohol from aqueous phase to micellar phase is –18.45, -18.59, -18.72 and -18.80 kJ·mol-1 for n = 8, 12, 14 and 16, respectively.

 

Indian Journal of Chemistry
Vol. 45A, April 2006, pp. 909-912

 

Catechol (1,2-dihydroxybenzene) inside charged film on electrode surface¾ A new voltammetric sensor for vitamin C

Rimki Bhattacharjya & Diganta Kumar Das*

Received 9 February 2005; revised 14 February 2006

Catechol shows good reversible cyclic voltammograms inside negative SDS, positive CTAB and zwitterionic phospholipid film on glassy carbon disc electrode in tris buffer (pH 7.0). The mid-point potential values with respect to Ag-AgCl reference electrode are found to be +120 mV, +90 mV and +135 mV, respectively. While inside the SDS film, catechol interacts with vitamin C in solution and the anodic current decreases with increasing concentration of vitamin C without any change in cathodic peak current and position. Although no interaction with vitamin C is observed when catechol is inside CTAB film, the mid-point potential of catechol inside lipid film is found to shift in negative direction when encapsulated in lipid film.

IPC Code: Int. Cl.8 G01N27/00

Indian Journal of Chemistry
Vol. 45A, April. 2006, pp. 913-916

 

Spectrophotometric determination of hydroxylamine and its derivatives in drug formulations by the indophenol reaction

B Deepa, K S Nagaraja* & N Balasubramanian

Received 18 April 2005; revised 7 February 2006

Hydroxylamine has been determined by its reduction to ammonium sulphate in Zn/H2SO4 column and Berthelot reaction of the formed ammonium sulphate using salicylic acid, sodium hypochlorite and sodium nitroprusside to give indophenol blue which is measured spectrophotometrically at 648 nm. The molar absorptivity is found to be 1.9´104 l mol-1cm-1. Beer’s law is obeyed in the range 2.5 - 25 mg of hydroxylamine in 10 ml of its solution. For the determination of 1.5 μg/ml of hydroxylamine, the RSD is 2.8% (n=10). The developed method has been applied for the determination of hydroxylamine and its derivatives after hydrolysis in drug formulations. The results obtained by the present method compare well with those obtained by the available reference method and with the standard addition of hydroxylamine.

IPC Code: Int. Cl.8 G01N21/00