Indian Journal of Chemistry

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

 

VOLUME 47A

NUMBER 10

October 2008

 

CONTENTS

 

 

1473

 

Stability and spectroscopic studies on oxygenated armchair SWCNTs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N Su, Q Guo & S Wu*

 

 

 

 

The energy gaps of the SWCNTs decrease with the increase in the size and length of the SWCNTs. The oxygenated SWCNTs with open structures are more stable than those with epoxy structures due to their low total energies and wide energy gaps.

 

(a) (3,3)-O(s) (C36O)       (b) (3,3)-O(v) (C36O)

 

(c) (3,3)-O(v) (C48O)                    (d) (3,3)-O(v) (C60O)

 

 

 

1480

 

Synthesis, spectroscopic and structural studies on
N-(2-hydroxyphenyl)cinnamaldimine and some bivalent metal complexes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rajib Lal De*, Mahuya Mandal, Lovely Roy, Jaydeep Mukherjee, Ruchika Bhawal &
Kamales Maiti

 

 

 

 

The bidentate Schiff base, CINOPH, obtained from the condensation of cinnamaldehyde with 2- aminophenol undergoes facile complexation reactions to form MII(CINOP)2 (M= Cu, Ni, Co and Zn), in which coordination is through imino nitrogen
(-CH=N-) and amino phenolic (-OH) oxygen.

 

 

 

1486

 

Ce(IV) oxidation of alcohols using cetyltrimethyl-ammonium ceric nitrate

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Biswa B Nayak, Sandhyamayee Sahu, Sabita Patel, Sukalyan Dash & Bijay K Mishra*

 

 

 

 

Oxidation of some primary aliphatic and alicyclic alcohols in acetonitrile medium by cetyltrimethylammonium ceric nitrate has been investigated. The decrease in the rate with increase in concentration of CTACN has been attributed to the formation of reversed micelles by the oxidant in organic medium.

 

 

 

1491

 

Solvent effects on ester linkage of 4-nitrophenyl acetate in aqueous and ethanol solutions with imidazole and hydroxide ion as nucleophiles

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Seham S Al-Terairy, Salim Basaif &
Abbas A El-Awady*

 

 

 

 

The reaction of 4-nitrophenyl acetate in aqueous and ethanol solutions with imidazole as a nucleophile has been monitored spectrophotometrically. The second order rate constants of these reactions are 10 times higher in water than in alcoholic solutions.  Base hydrolysis reaction of the ester in buffered aqueous solution with OH¯ as the nucleophile has also been studied.

 

 

 

 

1497

 

Extraction chromatographic method of preconcentration and separation of lead(II) with high molecular mass liquid cation exchanger, Versatic 10

 

 

 

 

 

 

 

 

B Mandal* & U S Roy

 

 

 

 

A selective method has been developed for the quantitative extraction chromatographic separation of lead(II) with Versatic 10 coated on silanised silica gel from 0.1M acetate buffer at the optimum pH 4.5-6.0. Lead(II) has been separated from synthetic multi-component mixtures containing its congeners of the same analytical group, e. g., Cu(II), Sn(II), Hg(II) and Cu(II), Cd(II), Bi(III). The method is effective for removal and recovery of lead(II) from industrial waste and standard alloy samples following its preconcentration.

 

Notes

1503

 

 

Computing Wiener and Kirchhoff indices of a triangulane

 

 

 

 

 

 

 

 

 

 

 

 

 

M H Khalifeh, H Yousefi-Azari & A R Ashrafi*

 

 

 

 

The Wiener and Kirchhoff indices of a triangulane molecule T[n] are computed. A dendrimer shape graph E[n] has been associated with the molecular graph and then star-delta technique has been applied to calculate the Kirchhoff index of  T[n].

 

 

1508

 

Synthesis of multidentate ligands via reduction of Schiff base-zinc(II) complex and their use for in situ synthesis of potentially biomimetic Type I copper complexes

 

 

 

 

 

 

 

 

 

Harmeet Dhillon, Urvasini Singh, Pooja &
Sunita Kumbhat*

 

 

 

 

Novel nitrogen-sulphur multidentate ligands with highly asymmetric coordination environment have been synthesised. Subsequent in situ complexation with Cu(II) yields potentially biomimetic Cu(II) complexes.

 

 

 

 

1512

 

Twist grain boundary and blue phase in binary system of liquid crystalline materials

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Monika Gupta, Ranjana Vaid, Vandana Gupta & Rajinder K Bamezai*

 

 

 

 

 

 

1516

 

Fluorescence quenching of 2-naphthol by methyl acrylate in micellar medium

 

 

 

 

Sachita Sahu & Pradipta Kumar Behera*

 

 

 

 

Compartmentalisation of 2-naphthol and methyl acrylate affects the quenching process. Methyl acrylate is found to be more partitioned in the micellar phase and tunes the collisional quenching due to availability of the fluorophore in the micelle.

 

 

1520

 

Kinetics and mechanism of oxidation of some thioacids by benzyltrimethylammonium chlorobromate

 

 

 

 

 

 

 

 

 

Vandana Tiwari, S Kumbhani, I Shastri &
Vinita Sharma*

 

 

 

 

The oxidation of some thioacids, viz., thioglycollic, thiolactic and thiomalic acids, by benzyltrimethylammonium chlorobromate  has been studied in acetic acid.

 

 

 

1524

 

Effect of inorganic ions on surface properties of a non-ionic surfactant at various temperatures in aqueous medium

 

 

 

 

 

Ram Partap*  & O P Yadav

 

 

 

Studies on surface tension of the non-ionic surfactant, TX-100, in water and in the presence of aqueous Na2SO4 and Na3PO4 are reported at 288, 293 and 298 K. The micellization process appears to be endothermic in nature, while negative values of DG0m and positive values of DS0m support its spontaneity.

 

 

1528

 

Solid phase extraction of cerium(IV) with crosslinked poly(acrylic acid) coated on silica gel

 

 

 

 

 

Pranesh Chowdhury*, Susanta K Pandit & Bhabatosh Mandal*

 

 

 

 

A method has been developed for selective extraction and separation of Ce(IV) with the high molecular mass crosslinked poly(acrylic acid), coated on silanized silica gel. The effectiveness of the proposed method has been judged by analyses of several minerals, e. g., monazite, bastnasite and Al-Ce alloy.

 

 

1533

 

A rapid spectrophotometric method for the determination of molybdenum using ferron in industrial and environmental samples

 

 

 

 

 

Anil Kumar* & Rameshwar Dass

 

 

 

 

In presence of a large number of cations, anions and complexing agents, molybdenum(V) forms a yellow complex with ferron that is quantitatively extracted into tri-n-octylamine-chloroform from 1 M H2SO4 medium. The complex is stable for at least 24 h and shows an absorption maximum at 425 nm with molar absorptivity and Sandell’s sensitivity of 3.96×103 l mol-1 cm-1 and
0.02525 mg cm-2 Mo(V), respectively. The method obeys Beer’s law up to 31 mg ml-1 Mo(V).

 

 

 

Authors for correspondence are indicated by (*)


Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1473-1479

 

Stability and spectroscopic studies on oxygenated armchair SWCNTs

N Su, Q Guo & S Wu *

Received 23 January 2008; revised 20 August 2008

Theoretical studies on the electronic structures and spectroscopy of oxygenated armchair single-walled carbon nanotubes have been carried out using semi-empirical AM1 and INDO/CIS methods as well as density function theory. Based on the B3LYP/3-21G optimized geometries, the energies of the oxygenated SWCNTs have been calculated at B3LYP/6-31G(d) level. The energy gaps of SWCNTs decrease due to the addition of the oxygen atom. The oxygenated SWCNTs, in which the oxygen atoms are located on the vertical bonds relative to the main axis of SWCNTs are more stable than those in which the oxygen atoms are added on the sloping bonds. The first and strongest absorptions in the electronic spectra of the oxygenated SWCNTs computed using INDO/CIS method are red shifted in comparison with those of SWCNTs. The main absorptions in the IR spectra of the oxygenated SWCNTs calculated with AM1 method are blue shifted as compared with those of SWCNTs. These two kinds of oxygenated SWCNTs can be distinguished using the chemical shifts of the bridged carbon atoms calculated at B3LYP/3-21G level.

IPC Code: Int. Cl.8 B82B1/00

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1480-1485

 

Synthesis, spectroscopic and structural studies on
N-(2–hydroxyphenyl)cinnamaldimine and some bivalent metal complexes

 

Rajib Lal De*, Mahuya Mandal, Lovely Roy, Jaydeep Mukherjee, Ruchika Bhawal & Kamales Maiti

Received 29 April 2008; revised 10 September 2008

The bidentate Schiff base, CINOPH, obtained from the condensation of cinnamaldehyde with 2-aminophenol undergoes facile complexation reactions to form MII(CINOP)2 (M= Cu, Ni, Co and Zn). In these complexes coordination is through imino nitrogen (-CH=N-) and amino phenolic (-OH) oxygen as revealed by the results of their elemental analyses, spectral, magnetic and electrochemical properties and single crystal X-ray crystallographic structure analysis performed on CINOPH (monoclinic, C2/c; Z, 8) and Cu(CINOP)2( monoclinic, C2/c; Z, 4).

IPC Code: Int. Cl.8 CO7C251/02; CO7F1/08; CO7F3/06; CO7F15/04; CO7F15/06

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1486-1490

 

Ce(IV) oxidation of alcohols using cetyltrimethylammonium ceric nitrate

Biswa B Nayak, Sandhyamayee Sahu, Sabita Patel, Sukalyan Dash & Bijay K Mishra*

Received 9 May 2008; revised 28 August 2008

Cetyltrimethylammonium ceric nitrate (CTACN) has been used to oxidize some primary aliphatic and alicyclic alcohols in acetonitrile medium and the reaction kinetics have been investigated by spectrophotometric method. The decrease in the rate with increased concentration of CTACN has been attributed to the formation of reversed micelles by the oxidant in organic medium. An asymptotic decrease in rate with increase in [CTAB] supports the reversed micellization in the reaction medium. The plots of rate constants with [substrate] reflect the partitioning of the substrate in the reversed micellar system of CTACN. The kinetic isotope effect (kH/kD) of 1.97 has been attributed to the dehydrogenation mechanism for the oxidation of alcohols.

IPC Code: Int. Cl.8 C07B33/00

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1491-1496

 

Solvent effects on ester linkage of 4-nitrophenyl acetate in aqueous and ethanol solutions with imidazole and hydroxide ion as nucleophiles

 

Seham S Al-Terairy, Salim Basaif & Abbas A El-Awady*

Received 1 January 2008; revised 28 August 2008

The reaction of 4-nitrophenyl acetate in aqueous and ethanol solutions with imidazole as a nucleophile has been monitored spectrophotometrically. The second order rate constants of these reactions are 10 times higher in water than in alcoholic solutions. This is attributed to better solvation of the initial state and less solvation of the excited state in the alcohol medium. The entropy of activation in water is more negative indicating the greater structuredness of the excited state in water. In addition to the above, the base hydrolysis reaction of the ester using OH- as a nucleophile in buffered aqueous solutions has been followed spectrophotometrically as a function of pH. The observed pseudo first order rate constant obeys the relationship kobs=ko+kOH [OH-] where ko represents the water reactions and the buffer dependent rate constant, and kOH is the rate constant for the OH- catalyzed (specific base) reaction. For both cases, a mechanism involving a tetrahedral intermediate and in which the nucleophile attacks at the electrophillic carbon of the ester C=O is proposed.

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1497-1502

 

Extraction chromatographic method of preconcentration and separation of lead(II) with high molecular mass liquid cation exchanger, Versatic 10

B Mandal* & U S Roy

Received 1 May 2008; revised 2 September 2008

A selective method has been developed for the extraction chromatographic separation of lead(II) with Versatic10 (liquid cation exchanger) coated on silanised silica gel. Its quantitative extraction has been achieved from 0.1M acetate buffer at the optimum pH 4.5-6.0. The effects of pH, flow-rate, stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to lead(II) has been determined. The extraction equilibrium constant (Kex) and different standard thermodynamic parameters have also been calculated by temperature variation method. The effect of pH on Rf values in ion exchange paper chromatography has been investigated. Lead(II) has been separated from synthetic multi-component mixtures containing various metal ions associated with it in ores and alloy samples. The method effectively permits sequential separation of lead(II) from synthetic quaternary mixture containing its congeners Cu(II), Sn(II), Hg(II) and Cu(II), Cd(II), Bi(III) of the same analytical group. The method is found effective for removal and recovery of lead(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of lead(II) has been suggested.

IPC Code: Int. Cl.8 B01D15/04; G01N30/96

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1503-1507

 

Computing Wiener and Kirchhoff indices of a triangulane

 

M H Khalifeh, H Yousefi-Azari & A R Ashrafi*

Received 19 June 2008; revised 6 July 2008

The Wiener index of a triangulane molecule T[n] has been computed and then a dendrimer shape graph has been associated with this molecular graph by which it is possible to calculate the Kirchhoff index of the triangle molecule under consideration.

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1508-1511

 

Synthesis of multidentate ligands via reduction of Schiff base-zinc(II) complex and their use for in situ synthesis of potentially biomimetic Type I copper complexes

Harmeet Dhillon, Urvasini Singh, Pooja & Sunita Kumbhat*

Received 12 May 2008; revised 14 August 2008

In an attempt to simulate the properties of blue copper proteins three low molecular weight and low symmetric solid copper(II) complexes have been synthesized. Ligands with highly asymmetric coordination environment have been prepared in two steps. The first step involves synthesis of zinc-coordinated Schiff base of benzothiazolines, which are then subjected to reduction followed by removal of the metal ion from these reduced complexes. The free ligands thus generated are then used for in situ complexation with Cu(II). These complexes exhibit an intense SCu(II) charge transfer band at 600 nm with high extinction values, which is characteristic of Type I copper complexes. The conductivity, magnetic susceptibility and IR studies also support the assigned structures to the complexes.

IPC Code: Int. Cl.8 C07C251/02; C07F1/08; C07F3/06

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1512-1515

 

Twist grain boundary and blue phase in binary system of
liquid crystalline materials

Monika Gupta, Ranjana Vaid, Vandana Gupta &
Rajinder K Bamezai*

Received 9 January 2008; revised 8 September 2008

The behaviour of one chiral mesogenic material with another mesogen in a mixed system has been investigated The mixture of chiral component having smectic Q phase and chiral antiferroelectric smectic C phase and non-chiral component having nematic and smectic C phases exhibits some interesting mesophases like blue phase, twist grain boundary phase, smectic A phase and smectic C phase, both on cooling the isotropic melt as well as on heating the crystalline material. The appearance of twist grain boundary phase and blue phase, which is studied by optical microscope, lies in a very narrow temperature and composition range. These phases are illustrated by their optical textures. Twist grain boundary and blue phase in binary system of liquid crystalline materials.

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1516-1519

 

Fluorescence quenching of 2-naphthol by methyl acrylate in micellar medium

Sachita Sahu & Pradipta Kumar Behera*

Received 26 March 2008; revised 8 September 2008

The fluorescence quenching of 2-naphthol in presence of methyl acrylate has been studied in different concentrations of anionic (sodium lauryl sulphate) and cationic (cetyl trimethyl ammonium bromide) micelles. It is found that compartmentalization of 2-naphthol and methyl acrylate affects the quenching process. Increase of accommodation of the probe and the quencher in the micelles affects the Stern-Volmer quenching constant (KSV) for 2-naphthol and 2-naphtholate.

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1520-1523

 

Kinetics and mechanism of oxidation of some thioacids by benzyltrimethylammonium chlorobromate

Vandana Tiwari, S Kumbhani, I Shastri & inita Sharma*

Received 8 February 2008; revised 28 August 2008

The oxidation of some thioacids, viz., thioglycollic, thiolactic and thiomalic acids by benzyltrimethylammonium chlorobromate   (BTMACB) has been studied in acetic acid. The reaction is first order with respect to BTMACB. Michaelis‑Menten  type  of kinetics have been observed  with respect to the  reductants. The reaction has been studied in solvents of different compositions of acetic acid and water.  The solvent composition effect has been analysed using Grunwald-Weinstein equation.  A mechanism involving the formation of an intermediate complex in the pre-equilibrium and its subsequent decomposition in slow step has been proposed.

IPC Code: Int. Cl.8 C07B33/00

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1524-1527

 

Effect of inorganic ions on surface properties of a non-ionic surfactant at various temperatures in aqueous medium

 

Ram Partap* & O P Yadav

Received 14 December 2007; revised 6 June 2008

Studies on surface tension of iso-octyl phenoxy polyethoxy ethanol in water and in the presence of aqueous Na2SO4 and Na3PO4 salts having varying anion valency at 288, 293 and 298 K are reported. The values of critical micelle concentration, maximum surface excess concentration and minimum area per molecule of the surfactant at air-liquid interface have been evaluated. Thermodynamic parameters of micellization and those of adsorption have also been evaluated. The micellization process appears to be endothermic in nature while negative values of DG0m and positive values of DS0m support its spontaneity.

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1528-1532

 

Solid phase extraction of cerium(IV) with crosslinked
poly(acrylic acid) coated on silica gel

 

Pranesh Chowdhury*, Susanta K Pandit & Bhabatosh Mandal*

Received 5 October 2007; revised 22 August 2008

A selective method has been developed for extraction and separation of Ce(IV) with the high molecular mass crosslinked poly(acrylic acid), coated on silanized silica gel. The coated materials act as stationary phase for the extraction. The structure and thermal stability of crosslinked poy(acrylic acid) has been elucidated with the help of FTIR and TGA. Ion exchange and breakthrough capacity of the exchanger have been measured. Surface morphology of the exchanger has been studied by SEM. Ce(IV) has been separated quantitatively from various synthetic mixtures containing metal ions commonly present in thorium and uranium ores, minerals and fission products. The developed method has been tested for some real samples. A plausible mechanism for Ce(IV) extraction and elution has been suggested.

IPC Code: Int. Cl.8 B01D53/81

 

 

Indian Journal of Chemistry

Vol. 47A, October 2008, pp. 1533-1536

 

A rapid spectrophotometric method for the determination of molybdenum using ferron in industrial and environmental samples

 

Anil Kumar* & Rameshwar Dass

Received 18 February 2008; revised 22 August 2008

Ferron has been used as an analytical reagent for the extractive spectrophotometric determination of molybdenum(V) obtained from the reduction of molybdenum(VI) with ascorbic acid. Molybdenum(V) in presence of a large number of cations, anions and complexing agents forms a yellow complex with ferron that is quantitatively extractable into tri-n-octylamine-chloroform from 1 M H2SO4 medium. The complex is stable for at least 24 h and shows an absorption maximum at 425 nm with molar absorptivity and Sandell’s sensitivity of 3.96×103 l mol-1 cm-1 and 0.02525 mg cm-2 Mo(V), respectively. The method obeys Beer’s law up to 31 mg ml-1 Mo(V). For ten replicate determinations of 10 mg ml-1 Mo(V), the relative standard deviation is found to be 0.54%. The method is simple, selective, precise and rapid, and has been satisfactorily applied to the determination of molybdenum in aqueous, synthetic and technical samples of diverse matrices.

IPC Code: Int Cl.8 G01N21/25