Indian Journal of Chemistry

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

 

VOLUME 47A

NUMBER 11

November 2008

CONTENTS

 

1619

 

Electrochemical performance of nano-SiC prepared in thermal plasma

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ch Venkateswara Rao, S K Singh &
B Viswanathan*

 

 

 

 

Ultrafine SiC has been synthesized by thermal plasma method and used as support for Pt. The material has been characterized by X-ray diffraction, scanning electron microscopy, energy dispersive
X-ray analysis and transmission electron microscopy. Electrochemical measurements indicate that the ORR activity of the Pt/SiC is comparable to that of the commercial Pt/C (E-TEK) catalyst.

 

 

 

1626

 

Synthesis of nano sized hydroxyapatite powder using sol-gel technique and its conversion to dense and porous bodies

 

 

 

 

 

 

 

 

 

 

 

 

Iis Sopyan*, Ramesh Singh & Mohammed Hamdi

 

 

 

 

Hydroxyapatite powder has been prepared via sol-gel procedure using calcium nitrate tetrahydrate and diammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. Performance of the material has been tested by making dense and porous samples.

 

 

 

1632

 

FT-IR, FT-Raman spectra and ab initio HF and DFT calculations of 2-nitro- and 4-nitrobenzaldehydes

 

 

 

 

 

S Kalaichelvan, N Sundaraganesan* &
B Dominic Joshua

 

 

 

 

Ab initio and density functional theory calculations have been carried out on the structures and vibrational spectrum of 2-nitro- and 4-nitrobenzaldehydes. Structural parameters obtained by B3LYP are in good agreement with experimental results. Vibrational frequencies calculated by B3LYP/6-311++G(d,p) method agree very well with experimental results.

 

 

1642

 

Structural and photophysical aspects of perylene- doped anthracene crystalline powders prepared by microwave heating

 

 

 

 

 

 

 

 

 

 

 

 

 

 

M N Gharge, S L Bhattar, G B Kolekar &
S R Patil*

 

 

 

 

Microwave assisted polycrystalline luminophors of anthracene have been prepared by addition of varying amounts of perylene dopant. XRD and SEM data indicate that the mixed crystalline powders are homogeneous and fine grained. Increase in stacking fault indicates closely packed stacked structure of perylene doped anthracene. Fluorescence studies show quenching of monomer fluorescence of anthracene by the perylene dopant.

 

 

 

1649

 

Kinetics and mechanism of Ru(III) catalyzed and uncatalyzed oxidation of atenolol by chloramine-T in perchloric acid medium

 

 

 

 

 

 

 

 

 

 

 

Puttaswamy* & N Suresha

 

 

 

 

The kinetics and mechanism of chloramine-T oxidation of atenolol in aqueous perchloric acid medium has been studied at
26 0.1C in the presence and absence of Ru(III) catalyst. The Ru(III) catalyzed reactions are 2-3 times faster than the uncatalyzed reactions.

 

Notes

 

1656

 

Synthesis of a new polymorph in [Cu(pyridine-2-carboxylate)2] system

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Daipayan Dutta, Atish Dipankar Jana,
Ambarish Ray, Jaromir Marek & Mahammad Ali*

 

 

 

 

[Cu(pic)2.2H2O]n, a pseudo polymorph of [Cu(pic)2]n, has doubly carboxylated bridged polymeric chains extending along the crystallographic a axis. These are joined to the adjacent parallel chains of the lattice water resulting in a 2D sheet in the (101) plane, which are further interdigitated and glued to each other by a novel C=O π interaction, into a 3D supramolecular motif.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


1661

 

Characterization and nuclease activity of mixed ligand Ni(II) complexes

 

 

 

 

 

 

 

 

 

 

 

 

 

M S Surendra Babu, P G Krishna,
K Hussain Reddy* & G H Philip

 

 

 

 

Mixed ligand complexes having molecular formulae Ni(L)2(L′)2 [where LH = salicylaldoxime or 2-hydroxyacetophenone oxime; L′= pyridine or imidazole] have been synthesized and characterized.

 

 

1666

 

Mechanistic study of oxidation of sulfacetamide by diperiodatocuprate(III) in aqueous alkaline medium

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P N Naik, S D Kulkarni, S A Chimatadar &
S T Nandibewoor*

 

 

 

 

The oxidation of sulfacetamide by alkaline diperiodatocuprate(III) has been studied at 298 K and at constant ionic strength. The reaction is first order in diperiodatocuprate(III) and has less than unit order in sulfacetamide concentration. A mechanism has been proposed wherein monoperiodatocuprate(III) is the active species.

 

 

 

1671

 

Kinetics and mechanism of oxidation of formic and oxalic acids by tetrakis(pyridine) silver dichromate

 

 

 

 

P Purohit, S Kumbhani, I Shashtri,
Kalyan K Banerji * & Pradeep K Sharma*

 

 

 

 

Kinetics and mechanism of oxidation of formic and oxalic acids by tetrakis(pyridine) silver dichromate in DMSO have been studied. The reaction is first order each with respect to the dichromate and the organic acids. The reaction is acid‑catalysed and the acid dependence has the form, kobs = a + b[H+].

 

1676

 

Silver selective electrode based on liquid membrane containing N2S2O2 macrocycle as ionophore

 

 

 

 

 

 

 

 

Susheel K Mittal*, S K Ashok Kumar,
Nidhi Rani Gupta, Mirac Ocak & Ummuhan Ocak

 

 

 

 

Plasticized membrane using 5,6:17,18-dibenzo,11,12-(4-nitrobenzo)-2,3-bis(hydroxyimine)-7,16-dithia-10,13-dioxo-4, 19-diaazacyclooctadecane based ionophore has been explored as Ag+ ion-selective sensor. Optimum performance is observed with PVC: plasticizer: ionophore in the ratio of 33: 65: 2 (wt. %). The sensor works satisfactorily in the concentration range of 2.5x10-5 to 1.0x10-1 M (detection limit 7.9x10-6 M) with a Nernstian slope of 58.5 mV/decade of activity over a wide pH range (5.09.0) with fast response time (15 s), non-aqueous tolerance (up to 30%) and shelf life of three months.

 

 

1681

 

Degradation of organic effluents containing wastewater by photo-Fenton oxidation process

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Modh Azam Sheikh, Anil Kumar, Mukesh Paliwal, Rameshwar Ameta* & R C Khandelwal

 

 

 

 

Photooxidation of some organic pollutants (p-nitroaniline,
p-aminophenols and acetanilide) has been carried out with photo-Fenton reagent in the presence of CdS. Excellent removal has been obtained using photo-Fenton process assisted with artificial irradiation.

 

Fe3+ + H2O + hn Fe+2 + OH + H+

Fe3+ + H2O2 + hn Fe2+ + O2H + H+

Fe2+ + H2O2 Fe3+ + OH + OH-

OH + H2O2 O2H + H2O

Fe2+ + OH Fe3+ + OH-

Fe3+ + O2H Fe2+ + O2 + H+

OH + OH H2O2

CdS (S.C.) + hn h+ (VB) + e-(CB)

H2O2 (abs) +2h+ O2 + 2H+

h+(VB) + H2O OH + H+

Organic compound + OH Products

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1619-1625

 

 

Electrochemical performance of nano-SiC prepared in thermal plasma

Ch Venkateswara Rao, S K Singh & B Viswanathan*

Received 26 June 2008; revised 8 October 2008

 

The possibility of using SiC as support for Pt and its use as alternate electrodes for fuel cell applications has been examined. Plasma technique and hydrogen reduction method have been employed for the preparation of nano-SiC and Pt/SiC respectively. These materials are characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and transmission electron microscopy. Powder XRD patterns of SiC and Pt/SiC reveal the existence of β-phase SiC and FCC structure of Pt. SEM and TEM analyses indicate a two-dimensional network of SiC chains and spherical shaped Pt particles on SiC support. EDX confirms the presence of Si and C in SiC and Pt, Si and C in the Pt/SiC samples. The electrochemical performance of Pt/SiC has been investigated by cyclic voltammetry. Oxygen reduction measurements performed by linear sweep voltammetry indicate that the as-prepared Pt/SiC catalyst exhibits ORR activity comparable with that of commercial Pt/C (E-TEK) catalyst.

IPC Code: Int. Cl.8 B01J21/00; B01J27/224; C25; H01M4/86; H05H1/00

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1626-1631

 

 

Synthesis of nano sized hydroxyapatite powder using sol-gel technique and its conversion to dense and porous bodies

Iis Sopyan*, Ramesh Singh & Mohammed Hamdi

Received 13 May 2008; revised 20 October 2008

Hydroxyapatite powder has been prepared via sol-gel procedure using calcium nitrate tetrahydrate and diammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. XRD measurement shows that the powder contains hydroxyapatite crystals with b-TCP and calcium oxide as secondary phases. Hydroxyapatite powder of higher purity, i. e., the correct Ca/P ratio, has been obtained by adding an appropriate amount of diammonium hydrogen phosphate and heating with stirring. Morphological evaluation by SEM measurement shows that the particles of the HA are tightly agglomerated and globular in shape with an average size of 1-2 mm. The primary particulates have average diameters of 50-200 nm, as detected by SEM and nanoparticle sizer. Purity (almost 100%) of the obtained hydroxyapatite has been confirmed by XRD analysis. Its performance has been tested by making dense and porous samples.

IPC Code: Int Cl.8 B82B3/00; C01B25/45; C01F11/00

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1632-1641

 

 

FT-IR, FT-Raman spectra and ab initio HF and DFT calculations of 2-nitro- and 4-nitrobenzaldehydes

 

S Kalaichelvan, N Sundaraganesan * & B Dominic Joshua

Received 9 May 2008; revised 10 October 2008

Combined experimental and theoretical studies on molecular and vibrational structure of 2-nitrobenzaldehydeand 4-nitrobenzaldehydes are reported. The Fourier transform infrared and Fourier transform Raman spectra of 2NB and 4NB has been recorded in the solid phase. The optimized geometry has been calculated by HF and B3LYP methods with 6-311++G(d,p) basis set. The harmonic vibrational frequencies of the title compounds have been performed at the same level of theories. The scaled theoretical wave numbers show very good agreement with the experimental values. The thermodynamic functions of the title compounds have also been computed at HF/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels of theory. A detailed interpretation of the infrared and Raman spectra of 2NB and 4NB is reported. The theoretical FT-IR spectra of the title molecules have also been constructed.

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1642-1648

 

 

Structural and photophysical aspects of perylene- doped anthracene
crystalline powders prepared by microwave heating

M N Gharge, S L Bhattar, G B Kolekar & S R Patil*

Received 25 March 2008; revised 25 September 2008

The microwave assisted polycrystalline luminophors of anthracene have been prepared by addition of varying amounts of perylene dopant. The crystallanity and homogeneity of mixed crystals have been examined by scanning electron microscopy. The structural parameters such as grain size, microstrain, dislocation density and stacking fault in mixed crystal growth have been estimated as a function of perylene concentration. The mixed crystalline powders are fine grained. Increase in stacking fault indicates closely packed stacked structure of perylene-doped anthracene. The fluorescence studies show quenching of monomer fluorescence of anthracene by perylene dopant. Higher concentration of perylene generates exciplex in the excited state, which is observed in the form of a broad, structureless, red shifted band. The fluorescence quenching and exciplex formation have been explained on the basis of excitation energy transfer and molecular interaction between anthracene and perylene. The fluorescence characteristics of mixed crystals are described using Stern-Volmer kinetics. The fluorescence results are correlated with structural parameters.

IPC Code: Int. Cl.8 C05B6/64; C09K11/06

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1649-1655

 

 

Kinetics and mechanism of Ru(III) catalyzed and uncatalyzed oxidation of atenolol by chloramine-T in perchloric acid medium

Puttaswamy* & N Suresha

Received 20 April 2008; revised 7 October 2008

The kinetics and mechanism of chloramine-T (CAT)-oxidation of atenolol (ATN) in aqueous perchloric acid medium have been studied at 26 0.1oC in the presence and absence of Ru(III) catalyst. Under identical experimental conditions, the reaction shows a first-order dependence on [CAT]0, a zero-order dependence on [ATN]0 and an inverse fractional-order dependence on [H+] for both the Ru(III) catalyzed and uncatalyzed reactions. The order with respect to Ru(III) is unity. Variation of ionic strength and addition of p-toluenesulfonamide or chloride ion have no effect on the rate. Decrease in dielectric constant of the reaction medium decreases the rate constant in both cases. Activation parameters have been computed. The stoichiometry of the reaction is found to be 1:4 and the main oxidation products are identified as 4-acetamidobenzeneoxyacetic acid and isopropyl amine. Based on the kinetic data, the conjugate acid, CH3C6H4SO2NHCl, is assumed to be the reactive oxidizing species in both cases. The Ru(III) catalyzed reactions are 2-3 times faster than the uncatalyzed reactions. Mechanisms consistent with the observed rate laws have been proposed.

IPC Code: Int. Cl.8 C07B33/00

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1656-1660

 

 

Synthesis of a new polymorph in [Cu(pyridine-2-carboxylate)2] system

Daipayan Dutta , Atish Dipankar Jana , Ambarish Ray , Jaromir Marek & Mahammad Ali *

Received 13 May 2008; revised 15 October 2008

Single crystal X-ray studies on a doubly carboxylate bridged {[Cu(pic)2].2H2O}n (1) (pic = pyridine-2-carboxylate) polymeric chains extending along the crystallographic a axis reveal that adjacent polymeric chains are joined by the lattice water chains running parallel to the polymeric chain leading to a 2D sheet in the (101) plane. The successive sheets are interdigitated and glued to each other by a novel C=Oπ interaction into a 3D supramolecular motif. The complex (1) can be regarded as a pseudo-polymorph of [Cu(pic)2]n which has been realized in two forms, violet (2) and blue-violet (3) from methanol

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1661-1665

 

 

Characterization and nuclease activity of mixed ligand Ni(II) complexes

M S Surendra Babu, P G Krishna, K Hussain Reddy * & G H Philip

Received 24 April 2008; revised 10 October 2008

Mixed ligand complexes having molecular formulae Ni(L)2(L)2 [where LH = salicylaldoxime(SAO) or 2-hydroxy-acetophenone oxime (HAO); L= pyridine or imidazole] have been synthesized and characterized by elemental analysis, molar conductivity, magnetic susceptibility, UV-vis and IR spectra. The magnetic moment and UV data suggest square planar geometry for parent complexes and octahedral geometry for mixed ligand complexes. Electrochemical studies have been carried out by cyclic voltammetry. The active signals are assignable to the NiII/I redox couple. Binding of metal complexes with calf thymus DNA is revealed by absorption spectrophotometry. The cleavage activity of complexes has been carried out on a double stranded pBR 322 circular plasmid DNA by using gel electrophoresis in the presence and in the absence of oxidant (H2O2).

IPC Code: Int Cl.8 C07F15/04

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1666-1670

 

 

Mechanistic study of oxidation of sulfacetamide by diperiodatocuprate(III) in aqueous alkaline medium

P N Naik, S D Kulkarni, S A Chimatadar & S T Nandibewoor*

Received 15 July 2008; revised 15 October 2008

The oxidation of sulfacetamide, a sulfonamide drug, by alkaline diperiodatocuprate(III) has been studied at 298 K and at constant ionic strength. The reaction is first order in diperiodatocuprate(III) and has less than unit order in sulfacetamide concentration. The rate constants increase with increase in alkali concentration and decrease with increase in periodate concentration. A mechanism has been proposed wherein monoperiodatocuprate(III) is the active species. The reaction constants involved in the different steps of the mechanism and the activation parameters for the slow step have been computed.

IPC Code: Int. Cl.8 C07B33/00

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1671-1675

 

 

Kinetics and mechanism of oxidation of formic and oxalic acids by tetrakis(pyridine) silver dichromate

P Purohit , S Kumbhani , I Shashtri, & Kalyan K Banerji *, & Pradeep K Sharma *

Received 15 July 2008; revised 8 October 2008

Kinetics and mechanism of oxidation of formic and oxalic acids by tetrakis(pyridine) silver dichromate (TPSD) in DMSO have been studied. The main product of oxidation is carbon dioxide. The reaction is first order each with respect to TPSD and the organic acids. The reaction is acid‑catalysed and the acid dependence has the form, kobs = a + b[H+]. The oxidation of a-deuterioformic acid exhibits a substantial primary kinetic isotope effect (kH/kD = 5. 65 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 cyclic transition state in the rate determining step. Suitable mechanisms have been proposed.

IPC Code: Int. Cl.8 CO7B33/00

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1676-1680

 

 

Silver selective electrode based on liquid membrane containing N2S2O2 macrocycle as ionophore

Susheel K Mittal *, S K Ashok Kumar , Nidhi Rani Gupta , Mirac Ocak & Ummuhan Ocak

 

Plasticizedmembraneusing5,6:17,18-dibenzo,11,12(4-nitrobenzo)-2, 3-bis(hydroxyimine)-7,16-dithia-10, 13-dioxo-4, 19-diaazacyclooctadecane (N2S2O2) based ionophore has been explored as Ag+ ion-selective sensor. Optimum performance is observed with membrane having composition of PVC, plasticizer and ionophore in the ratio of 33: 65: 2 (wt. %). Stability constants for different metal ions have been determined by conductometric titrations. The sensor works satisfactorily in the concentration range of 2.510-5 to 1.010-1 M (detection limit 7.910-6 M) with a Nernstian slope of 58.5 mV/decade of activity. Wide pH range (5.09.0), fast response time (15 s), non-aqueous tolerance (up to 30%) and adequate shelf life (3 months) indicate the vital utility of the proposed sensor. The proposed electrode shows good selectivity for Ag+ ion with respect to alkali, alkaline earth, transition and rare earth metal ions and can be used for its determination in binary mixtures. Determination of chloride contents in samples of Vitamin B1 and tap water has also been made by using the proposed electrode.

IPC Code: Int. Cl.8 G01N27/33

 

 

Indian Journal of Chemistry

Vol. 47A, November 2008, pp. 1681-1684

 

 

Degradation of organic effluents containing wastewater by photo-Fenton oxidation process

Modh Azam Sheikh, Anil Kumar, Mukesh Paliwal, Rameshwar Ameta* & R C Khandelwal

Received 17 June 2008; revised 16 October 2008

Photooxidation of someorganic pollutants(p-nitroaniline, p-aminophenols and acetanilide) has been carried out in the presence of photo-Fenton reagent. The effect of various parameters like pH, concentrations of organic compounds, ferric ions and hydrogen peroxide and light intensity, etc. on the reaction rate has been studied. The degradation is found to be pseudo first order. The optimum pHs for the degradation of p-aminophenol, p-nitroaniline and acetanilide are found to be 3.0, 3.5 and 2.5, respectively while the rate degradations of the three compounds are found to be comparable. The study shows that the photo-Fenton process are more effective and faster than Fenton's reagent in oxidation of organic compounds, and that the organic compounds are completely oxidized and degraded into CO2 and H2O. A tentative mechanism has been proposed. Excellent removal has been obtained using photo-Fenton process assisted with artificial irradiation. This study demonstrates that the use of photo-Fenton process on organic effluents wastewater treatment is very promising, especially when solar light is used.

IPC Code: Int. Cl.8 C02F1/72; C02F101/30; C02F103/34; C09B