Indian Journal of Chemistry

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

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VOLUME 51A

NUMBER 8

AUGUST 2012

CONTENTS

 

1049

 

La-doped TiO2 hollow fibers and their photocatalytic activity  under UV and visible light

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shuhua Yao, Xueying Jia, Lulu Jiao, Chuang Zhu & Zhongliang Shi*

 

 

 

Higher degradation of methyl orange has been achieved with
La-doped TiO2 hollow fibers. The 0.5 mol% La-doped TiO2 fiber shows the highest photocatalytic activity.

 

 

 

 

 

 

 

1057

 

A superoxide anion electrochemical sensor based on
the direct electrochemistry of superoxide dismutase assembled layer-by-layer at the L-cysteine modified
gold electrode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yan Yang, Jiawan Zhou, Liang Wu, Xiaohua Zhang & Jinhua Chen*

 

 

 

 

 
1064

 

Soft synthesis of a metal-organic framework based on a tribarium building block

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bikshandarkoil R Srinivasan*, Santosh Y Shetgaonkar & Pallepogu Raghavaiah

 

 

 

A new metal-organic framework [Ba3(btc)2(H2O)8]·2H2O
(btc = benzene-1,3,5-tricarboxylate) has been synthesized under mild reaction conditions and structurally characterized.

 

 

 

 

 

 

 
1073

 

Two step one-electron transfer reaction of chromium(III) complex containing carbidopa and inosine with N-bromosuccinimide

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ahmed A Abdel-Khalek* & Mahmoud M Abdel-Hafeez

 

 

 

Oxidation of [CrIII(Carbidopa)(Inosine)(H2O)4]2+ by
N-bromosuccinimide proceeds through an inner-sphere mechanism involving a rapid pre-equilibrium formation of
CrIII precursor complex followed by a slow intramolecular
two step one-electron transfer in the rate determing step
giving CrIV.

 

 

 

 

 

Notes

 

1080

 

Synthesis of Ti–β zeolite membrane over porous
α–alumina tubular support

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Manickam Sasidharan & Asim Bhaumik*

 

 

 

Three-dimensional large pore titanosilicate analogue of zeolite
beta membrane has been synthesized by hydrothermal method over porous α-alumina tubular support. Crack-free continuous intergrown membranes with thickness of ~10
mm are obtained after four repeated syntheses over the same alumina support with different synthesis gels.

 

 

 

 

1085

 

Non-ionic surfactant mediated preparation of
κ-carrageenan/calcium carbonate biocomposite

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sanjay Kumar, Kamalesh Prasad* & A K Siddhanta*

 

 

 

 

 

 

1090

 

Electrical conductivity of cuprous bromide in the temperature range of 30-490 °C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Kaman Singh*,  B C Yadav & Vimalesh Kumar Singh

 

 

 

 

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp.1049-1056

 

La-doped TiO2 hollow fibers and their photocatalytic activity
under UV and visible light

 

Shuhua Yao, Xueying Jia, Lulu Jiao, Chuang Zhu & Zhongliang Shi*

School of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang 110142, China

Email: shzhl2000@163.com

Received 20 March 2012; revised and accepted 19 July 2012

A series of La-doped TiO2 photocatalytic material with a hollow fiber structure has been successfully prepared using La(NO3)3·6H2O and Ti(OC4H9)4 as precursors and cotton fiber as the template. Scanning electron microscopy, X-ray diffraction, N2 adsorption-desorption measurements, UV-vis diffuse absorption spectra and X-ray photoelectron spectroscopy have been used to characterize the morphology, crystal structure, surface structure and optical absorption properties of the samples. The photocatalytic activity of the samples with varying amounts of La-doped has been studied by photodegradation of methyl orange in water under UV and visible light. Results show that La doping restrains the growth of grain size and extends the photoabsorption edge of TiO2 hollow fiber into the visible light region. The fiber structured material shows better photocatalytic properties for the degradation of methyl orange than pure TiO2 under UV and visible light. The amount of La-doping significantly affected the catalytic property. Under the experiment conditions, the photocatalytic activity of 0.5 mol% La-doped TiO2 fiber is optimal amongst the studied samples. The prepared La-doped TiO2 fiber is a low energy consuming, high activity and green environmental-friendly catalytic material.

Keywords: Photocatalysts, Titania, Lanthanum doping, Fiber templates, Photocatalytic activity, Methyl orange

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp. 1057-1063

 

A superoxide anion electrochemical sensor based on the direct
electrochemistry of superoxide dismutase assembled layer-by-layer
at the L-cysteine modified gold electrode

Yan Yang, Jiawan Zhou, Liang Wu, Xiaohua Zhang & Jinhua Chen*

State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering,
Hunan University, Changsha, 410082, PR China

Email: chenjinhua@hnu.edu.cn

Received 1 May 2012; revised and accepted 16 July 2012

A superoxide anion (O2) biosensor has been developed based on layer-by-layer assembled poly-(diallyldimethylammonium) (PDDA) and superoxide dismutase (SOD) on the L-cysteine (Cys) modified gold (Au) electrode. In 25 mM phosphate buffer solution (pH 7.2), the {SOD/PDDA}n/Cys/Au electrode shows a pair of well-defined and nearly reversible peak at ~ 84 mV vs SCE, confirming the direct electrochemistry of SOD. Based on the bifunctional enzymatic catalytic activities of SOD to the oxidation and reduction of O2, the developed {SOD/PDDA}5/Cys/Au electrode exhibits good analytical characteristics in the detection of O2, such as low detection limit, good stability, reproducibility, selectivity and particularly a wide linear range (0.5 ~ 546 mM).

Keywords: Superoxide anion, Superoxide dismutase, Electrochemistry, Poly-(diallyldimethylammonium), Sensors, Modified electrodes, Layer-by-layer assembly

 

 

 

 

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp. 1064-1072

 

Soft synthesis of a metal-organic framework based on a
tribarium building block

Bikshandarkoil R Srinivasana, *, Santosh Y Shetgaonkara & Pallepogu Raghavaiahb

aDepartment of Chemistry, Goa University, Goa 403 206 India

Email: srini@unigoa.ac.in

bNational Single Crystal X-ray Diffractometer Facility, School of Chemistry,

University of Hyderabad, Hyderabad 500 046 India

Received 16 May 2012; revised and accepted 18 July 2012

Reaction of MCO3 (M = Ba or Ca) with benzene-1,3,5-tricarboxylic acid (H3btc) in aqueous medium at room temperature affords in good yields the metal-organic framework material [Ba3(btc)2(H2O)8]·2H2O (1) or the layer compound [Ca3(btc)2(H2O)12] (2). The structure of (1) is a three-dimensional polymer based on a tribarium building unit. In the trinuclear building block, the central Ba(II) situated on an inversion centre exhibits ten coordination, while the symmetry equivalent terminal Ba(II) ions are eight coordinated. The μ6-heptadentate bridging binding mode of the unique btc ligand in (1) results in a 3-D structure with two water molecules situated in the pores. Compound (2) exhibits a two-dimensional structure, unlike the compositionally similar d-block compounds [M3(btc)2(H2O)12] (M = Co, Ni, Zn) which are one-dimensional. A comparative study of several compounds containing the {M3(btc)2} unit is described.

Keywords: Coordination chemistry, Metal-organic framework, Coordination polymers, Barium, Calcium, Trinuclear compounds, Benzene-1,3,5-tricarboxylic acid

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp. 1073-1079

 

Two step one-electron transfer reaction of chromium(III) complex containing carbidopa and inosine with N-bromosuccinimide

Ahmed A Abdel-Khaleka, * & Mahmoud M Abdel-Hafeezb

aChemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef City, Egypt

Email: ahmed41_chem40@yahoo.com

bForensic Medicine Authority, Ministry of Justice, Cairo, Egypt

Received 8 December 2011; revised and accepted 14 June 2012

Oxidation of [CrIII(CD)(Ino)(H2O)4]2+ (where CD = carbidopa, Ino = inosine) with N-bromosuccinimide (NBS) was studied kinetically in aqueous media over varying ranges of concentrations of complex (1.0-5.0) × 10-4 mol dm-3  and NBS (0.5-5.0) × 10-2 mol dm-3, pH, ionic strength and temperature. The reaction is first order with respect to [CrIII] and [NBS]. The rate of reaction increases with increasing pH over the studied range (6.76-7.84). The anionic surfactant, sodium dodecyl sulphate is found to increase the rate of the oxidation in the range (0.0-1.0) × 10-3 mol dm-3. Thermodynamic activation parameters have also been calculated. The rate of oxidation obeys the equationd[CrVI]/dt = {k3 + k2 (1/[H+])}[NBS][[CrIII(CD)(Ino)(H2O)4]2+]. The experimental rate law is consistent with the proposed mechanism in which the protonated and deprotonated species are involved in the rate determing step. It is proposed that a two step one-electron transfer takes place via an inner sphere mechanism.

Keywords: Kinetics, Reaction mechanisms, Carbidopa, Inosine, Chromium, Electron transfer

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp. 1080-1084

 

Synthesis of Ti–β zeolite membrane over porous α–alumina tubular support

Manickam Sasidharana & Asim Bhaumikb, *

aLaboratory for Membrane Chemistry, AIST Tohoku, 4-2-1 Nigatake, Miyagino-ku, Sendai 983-8551, Japan

bDepartment of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India

Email: msab@iacs.res.in

Received 16 August 2011; revised and accepted 17 July 2012

Three-dimensional large-pore titanosilicate analogue of zeolite Beta membrane has been synthesized for the first time through hydrothermal method over porous α-alumina tubular support. Crack-free continuous intergrown membranes are obtained after four repeated syntheses over the same alumina support but with different synthesis gels. The thickness of the calcined Ti–β membrane is found to be ≈9 ± 2 μm. The calcined composite membranes have been characterized by powder X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray analysis, UV-visible diffuse reflectance spectroscopy and elemental analysis by inductively coupled plasma studies. The XRD patterns of composite membrane and powder sample collected from the reactor suggest the formation of pure crystalline titanium Beta phase. The UV-visible spectrum confirms the presence of titanium predominantly in the tetrahedral position. The gas permeability of the membranes at room temperature at different inlet pressure is of the order of 10–8. Prior to calcination, the composite membranes do not show any gas permeability indicating high compactness of the synthesized membrane.

Keywords: Metallosilicates, Titanosilicates membranes, Zeolite membranes, Microporous membranes, Hydrothermal synthesis, Pore structures, Gas permeation, Alumina tubes

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp.1085-1089

 

Non-ionic surfactant mediated preparation of κ-carrageenan/calcium carbonate biocomposite

Sanjay Kumar, Kamalesh Prasad* & A K Siddhanta*

Marine Biotechnology and Ecology Discipline, CSIR-Central Salt & Marine Chemicals Research Institute,
GB Marg, Bhavnagar 364 002, Gujarat, India

Email: kamlesh@csmcri.org (KP)/ aks@csmcri.org (AKS)

Received 19 December 2011; revised and accepted 14 July 2012

Non-ionic surfactants mediated biocomposites of k-carrageenan have been prepared by incorporating CaCO3 particles generated in situ under microwave heating. The CaCO3 particles generated in presence of a sugar surfactant (SUC-PEO) has near spherical shape in comparison to that prepared in presence of Brij 35. The products have been characterized for their thermal stability, swellability in aqueous medium, crystallinity and microstructures. Reasonable degree of porosity is introduced in the biocomposites by chelating out CaCO3 particles using EDTA.

Keywords: Composites, Biocomposites, Calcium carbonate, Surfactants, Thermal stability, Swellability, Microstructures, Porosity

 

Indian Journal of Chemistry

Vol. 51A, August 2012, pp. 1090-1094

 

Electrical conductivity of cuprous bromide in the temperature range of 30-490 °C

Kaman Singha, *, †, B C Yadavb & Vimalesh Kumar Singha

aDepartment of Chemistry, University of Lucknow 226 007, India

bDepartment of Physics, University of Lucknow 226 007, India

Email: drkamansingh@yahoo.com

Received 28 August 2011; revised and accepted 19 July 2012

The electrical conductivity (dc) of solid CuBr has been determined employing the cell configuration Cu/CuBr/Cu over a wide range of temperature (30 – 490 °C) which allowed the phase transformations: γ-CuBr ↔ β-CuBr and β-CuBr ↔ α-CuBr. With the measured conductivities, activation energy and pre-exponential factors have been evaluated over the studied range of temperature. Transport properties in the respective phases are discussed and compared with those reported in the literature. Though the order of magnitude of observed conductivity is same as that reported in literature, the observed values are higher than those reported earlier. The electrical conductivity of γ-CuBr increases rapidly with temperature, from 2.51 × 10-3-1 m-1 at 50 °C to 16.08 Ω-1 m-1 at 400 °C. After the first phase transition of γ-CuBr ↔ β-CuBr, the electrical conductivity attains a value of 148 Ω-1m-1 and increases further with increase in temperature. The conductivity increases by about 30 % on β-phase ↔ α-phase transition (maximum value 377.60 Ω-1m-1 at 487 °C). Activation energies for conduction of γ-CuBr are found to be 85.58 kJ mol-1 (30-225 °C) and 145.35 kJ mol-1 (320-380 °C) whereas for β-CuBr it is 22.45 kJ mol-1 and for the superionic α-phase it is 2.38 kJ mol-1.

Keywords: Conductivity, Cuprous bromide, Activation energy, Phase transformations