Indian Journal of Chemistry

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

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VOLUME 49A

NUMBER 8

August 2010

CONTENTS

Advances in Contemporary Research

 

1003

 

Interaction of DNA with small molecules: Role of copper histidyl peptide complexes in DNA binding and hydrolytic cleavage

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pulimamidi Rabindra Reddy* & Addla Shilpa

 

 

 

The importance of DNA binding and cleavage and the role of  copper histidyl peptide complexes in DNA binding and hydrolytic cleavage has been reviewed.

 

 

 

 

Papers

 

1016

 

Theoretical studies on the stability and spectroscopy of C82O2 based on C82 (C3v)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Y Wang, H Zhang, S Yuan & S Wu *

 

 

 

The equilibrium geometries of the twenty possible isomers of C82O2 are studied using density function theory. The most stable isomer of C82O2 is 32,56,31,53-C82O2, where annulene-like structures with two oxygen atoms added to the 6/6 bonds on the same hexagon are formed. The energy gaps of the C82O2 isomers are basically wider than that of C82 (C3v) due to the high stability of C82O2.

 

 

 

1023

 

Structure-function mimicry of oxidized purple acid phosphatase-PAPox – A new functional model

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shobha A Waghmode*, Sadgopal K Date,
Vidya S Gupta & Sandhya Y Rane*

 

 

 

Electronic structure and spectroscopic properties of novel diiron active site of oxidized mammalian purple acid phosphatase analogues, Fe-6: [Fe2(μ-O)(μ-OAc)(4HNSQox)(ONSQox)2(H2O)4] and Fe-7: [Fe2(μ-O)(μ-OAc)(ONSQox)2(OAc)(H2O)4], are described. Only Fe-6 shows analogous physiological DNA cleavage activity on pUC19 plasmid and acts as a good model of oxidized purple acid phosphatase enzyme.

μ

 

 

 

1030

 

Electrochemical reduction of tartrazine at multi-walled carbon nanotube-modified pyrolytic graphite electrode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Y Z Song*, J M Xu, J S Lv, H Zhong, Y Ye &
J M Xie

 

 

 

The electrochemical reduction of tartrazine at a multiwalled carbon nanotube-modified pyrolytic graphite electrode is investigated by cyclic voltammetry. The relative standard deviation for the peak current based on six replicates is 1.2 %, This method has been satisfactorily applied for the determination of tartrazine in real samples in the concentration range of
2.0 – 70.0 mg L-1 and 70.0 – 230.0 mg L-1, with a detection limit of 0.5 mg L-1. On daily usage and storing under ambient conditions for 2 weeks, the MWCNT/PGE electrode retains
96.3 % of its initial peak current response for tartrazine concentration of 50.0 mg L-1.

 

Notes


 

1035

 

Solar photocatalytic degradation of Acid Black 1 with ZnO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B Krishnakumar & M Swaminathan*

 

 

 

ZnO is found to be more efficient than TiO2-P25 for degradation of AB 1 under solar light. The optimum pH and catalyst concentration for efficient removal of 2 ´ 10–4 M dye are found to be 9 and 6 g L–1, respectively.

 

 

Text Box: AB 1 remaining (%)

 

 

1041

 

Catalytic activity of enzyme in water/organic cosolvent mixtures for the hydrolysis of p-nitrophenyl acetate
and p-nitrophenyl benzoate

 

 

 

 

 

 

 

 

 

 

Santosh Kumar Verma & Kallol K Ghosh*

 

 

 

Dependence of the catalytic activity of α-chymotrypsin on the concentration of organic cosolvents (acetonitrile, dimethyl sulfoxide, dimethyl formamide, ethylene glycol, methanol, ethanol, propan-2-ol and tert-butanol) in mixed aqueous media has been studied towards hydrolysis of p-nitrophenyl acetate and p-nitrophenyl benzoate using cetyltriphenylphosphonium bromide surfactant at pH 7.75. Under the conditions employed, the reaction follows a Michaelis-Menten mechanism. The catalytic efficiency of α-chymotrypsin is enhanced in aqueous-organic media.

 

 

 

1047

 

Synthesis and characterization of gallosilicate halide sodalites using organic solvent

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A V Borhade* & S G Wakchaure

 

 

 

The crystallization of gallosilicate sodalite containing halides
(Cl, Br and I) in 30 % ethanol has been investigated at low temperature (373 K) using a one-pot synthesis method. The crystal structures show cubic symmetry in a space group P3n with unit cell parameter, a = 8.9502, 8.9986 and 9.0779 Ĺ for chloro, bromo and iodo sodalite respectively. The corresponding
Ga-O-Si angles are 134.453, 135.252 and 136.887°. The MAS NMR data confirm the alternating Ga and Si ordering of sodalite framework.

 

 

 

1052

 

EDXRF determination of Dy, Eu, Gd and Sm in aqueous solutions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N K Porwal, V Natarajan*, Mithlesh Kumar,
B Rajeswari, M J Kulkarni, M K Bhide,
B A Dhawale & S V Godbole

 

 

 

An EDXRF technique for the determination of four important rare earth impurities, viz., Eu, Dy, Sm and Gd, at 20-1000 mg/ml in aqueous medium as well as in the presence of uranium has been reported. The limit of detection for the analytes in aqueous solutions is found to be 20 mg/ml. In the presence of uranium at
1 mg/ml, the detection limit is higher at 75 mg/ml. By dispersing the rare earth analytes in PVA films, the limit of detection by EDXRF method improves to 5 mg/ml.

 

 

 

1056

 

Announcement

 

 

 

Authors for correspondence are indicated by (*)

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1003-1015

 

 

Interaction of DNA with small molecules: Role of copper histidyl peptide complexes in DNA binding and hydrolytic cleavage

Pulimamidi Rabindra Reddy* & Addla Shilpa

Department of Chemistry, Osmania University, Hyderabad 500 007, India

Email: rabi_pr@rediffmail.com

Received 19 March 2010; revised and accepted 17 July 2010

           Deoxyribonucleic acid is the site of storage and retrieval of genetic information through interaction with proteins and other small molecules. Hydrolysis of the phosphodiester bond of DNA is of critical importance at several stages in a cell cycle. Thus, the development of metal complexes that cleave nucleic acids hydrolytically at physiological conditions is of great interest in the field of artificial metallonucleases. Among transition metals, Cu(II) complexes have been extensively studied in promoting hydrolysis of DNA. Histidine is a biologically important ligand for Cu(II) binding in many biological systems. Since imidazole is an efficient catalyst for ester hydrolysis at neutral pH and histidine residues are often involved in neutral hydrolytic metalloenzyme active centres and have the potential to bind to DNA, an attempt is made in this review to highlight the importance of DNA binding and cleavage and the role of a few copper histidyl peptide complexes in DNA binding and hydrolytic cleavage.

Keywords: Bioinorganic chemistry, DNA cleavage, Copper, Hydrolysis, Metalloenzymes

IPC Code: Int. Cl.9 CO7F1/08

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1016-1022

 

Theoretical studies on the stability and spectroscopy of C82O2
based on C82
(C3v)

Y Wanga, b, H Zhangb, S Yuanb & S Wua, *

aDepartment of Chemistry, bDepartment of Chemical and Biochemical Engineering, Zhejiang University,
Hangzhou 310027, PR China

Email: wushi@zju.edu.cn

Received 5 May 2010; revised and accepted 12 July 2010

           The equilibrium geometries of the twenty possible isomers of C82O2 have been studied using density function theory. The most stable isomer of C82O2 has been found to be 32,56,31,53-C82O2, where the annulene-like structures are formed. The energy gaps of the C82O2 isomers are basically wider than that of C82 (C3v) due to the high stability of C82O2. The chemical shifts of the bridged carbon atoms in C82O2 have been changed upfield in contrast to those of the corresponding carbon atoms in C82 (C3v) since the electronic density around these carbon atoms increases due to the addition of the oxygen atoms. Most of the isomers with annulene-like structures of C82O2 are weakly aromatic, while those with epoxy structures are highly aromatic. The C82O2 isomers with wide energy gaps show high aromaticity.

Keywords: Theoretical chemistry, Fullerenes, Energy gap, Chemical shifts, Aromaticity, Density function

theory, NMR spectroscopy, Electronic structure

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1023-1029

 

Structure-function mimicry of oxidized purple acid phosphatase-PAPox –
A new functional model

Shobha A Waghmodea, *, Sadgopal K Dateb, Vidya S Guptac & Sandhya Y Raned, *

aDepartment of Chemistry, Abasaheb Garware College, Pune 411 004, India

bDepartment of Physics, University of Pune, Pune 411 007, India

cPlant Molecular Biology, National Chemical Laboratory, Pune 411 008, India

dDepartment of Chemistry, University of Pune, Pune 411 007, India

Email: syrane@chem.unipune.ernet.in

Received 27 October 2009; re-revised and accepted 21st July 2010

           Electronic structure and spectroscopic properties of the novel diiron active site of oxidized mammalian purple acid phosphatase analogues, Fe-6: [Fe2 (µ-O) (µ-OAc) (4HNSQox)(ONSQox)2(H2O)4] and Fe-7: [Fe2 (µ-O)
(µ-OAc)(ONSQox)2
(OAc) (H2O)4] are described. Magnetic susceptibility SQUID data of Fe-6 are best fitted to Heisenberg’s isotropic spin pair (S = 5/2, 3/2) model using magnetic parameters g = 2 and J = – 36.8 cm-1 with R factor = 6.4 × 10-4. The antiferromagnetic exchange establishes Fe(III)-O-Fe(III) dimeric core with Fe(III) site having two radical ligations in the naphthosemiquinone oxime form of lawsone oxime. In the model compound Fe-7 of oxidized purple acid phosphatase, bridged and terminal acetate functions are identified according to their different energies of activations, i.e, ~34 and 58 kJ mol-1 respectively. Also, the reduced naphthoquinone oxime form of ligand is characterized by its energy of activation (~15 kJ mol-1) from pyrolytic reaction. Mössbauer parameters, d = 0.4 mm s-1 and DEQ = 0.8 mm s-1, are characteristics of oxidized Fe(III) in high spin octahedral site. Only Fe-6 shows analogous physiological DNA cleavage activity on pUC19 plasmid and acts as a good model of oxidized purple acid phosphatase enzyme.

Keywords: Bioinorganic chemistry, Nuclease activity, PAPox analogues, Iron, DNA cleavage Antiferromagnetic exchange

IPC Code: Int. Cl.9 C07F15/02

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1030-1034

 

Electrochemical reduction of tartrazine at multi-walled carbon
nanotube-modified pyrolytic graphite electrode

Y Z Songa, *, J M Xua, J S Lva, H Zhonga, Y Yeb & J M Xiec

aJiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials,
School of Chemistry & Chemical Engineering, Huaiyin Normal University,
Huai An 223300, People’s Republic of China

Email: songyuanzhi@126.com

bKey Laboratory for the Synthesis and Application of Organic Functional Molecules,
Ministry of Education, Hubei University, Wuhan, 430062, People’s Republic of China

cSchool of Chemistry & Chemical Engineering, Jiangsu University,
Zhenjiang, 212013, People’s Republic of China

Received 3 June 2010; revised and accepted 23 July 2010

           The electrochemical reduction of tartrazine at a multiwalled carbon nanotube-modified pyrolytic graphite electrode is investigated by cyclic voltammetry. A simple, sensitive and inexpensive method for determination of tartrazine is proposed. The accuracy and reproducibility of the determination method have been evaluated. On using the MWCNT/PGE daily and storing under ambient conditions over a period of 2 weeks, the electrode has retained 96.3 % of its initial peak current response for a tartrazine concentration of 50.0 mg L-1. The relative standard deviation for the peak current based on six replicates is 1.2 %, This method has been satisfactorily applied for the determination of tartrazine in real samples in the concentration range of 2.0 – 70.0 mg L-1 and 70.0 – 230.0 mg L-1, with a detection limit of 0.5 mg L-1.

Keywords: Electrochemistry, Cyclic voltammetry, Carbon nanotubes, Pyrolytic graphite electrode, Reductions, Dyes, Azo compounds

IPC Code: Int. Cl.9 B82B1/00; GOIN27/00; H01M4/00

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1035-1040

 

Solar photocatalytic degradation of Acid Black 1 with ZnO

B Krishnakumar & M Swaminathan*

Department of Chemistry, Annamalai University, Annamalainagar 608 002, India

Email: chemres50@gmail.com

Received 1 June 2010; revised and accepted 26 July 2010

           The degradation of an azo dye, Acid Black 1 (AB 1) with ZnO as photocatalyst using natural solar light in aqueous solution has been investigated under different conditions. The degradation is more with solar/ZnO process than with solar/TiO2-P25 process at pH 9. The influence of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photodegradation by ZnO has been analyzed. The degradation of AB 1 follows pseudo-first order kinetics according to the Langmuir-Hinshelwood model. The intermediates formed during the photodegradation have been identified by GC-MS analysis. The mineralization of AB 1 has been confirmed by cyclic voltammetric and COD measurements.

Keywords: Photocatalysis, Photodegradation, Solar light, Azo dyes, Oxides

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1041-1046

 

Catalytic activity of enzyme in water/organic cosolvent mixtures for the hydrolysis of p-nitrophenyl acetate and p-nitrophenyl benzoate

Santosh Kumar Verma & Kallol K Ghosh*

School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur (C.G.), 492 010, India

Email: kallolkghosh@yahoo.com

Received 25 June 2010; revised and accepted 26 July 2010

           The dependence of the catalytic activities of α-chymotrypsin on the concentration of organic cosolvents (acetonitrile, dimethyl sulfoxide, dimethyl formamide, ethylene glycol, methanol, ethanol, propan-2-ol and
tert-butanol
) in mixed aqueous media has been studied towards hydrolysis of p-nitrophenyl acetate and p-nitrophenyl benzoate using cetyltriphenylphosphonium bromide surfactant at pH 7.75. The temperature dependence hydrolysis of PNPA and PNPB catalyzed by α-chymotrypsin has also been reported. Under all the conditions employed, the reaction follows a Michaelis-Menten mechanism. The organic solvent influences the kcat and KM. The effect of polarity of solvent on the catalytic activity has been discussed. It is observed that the catalytic efficiency of α-chymotrypsin is enhanced in aqueous-organic media. Possible mechanism of micellar enzymology and the effect of organic co-solvents have been discussed.

Keywords: Solvent effects, Surfactants, Hydrolysis, a-Chymotrypsin

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1047-1051

 

Synthesis and characterization of gallosilicate halide sodalites using organic solvent

A V Borhade* & S G Wakchaure

Research Centre, Department of Chemistry, HPT Arts and RYK Science College, Nasik 422 005, India

Email: ashokborhade2007@yahoo.co.in

Received 23 April 2010; revised and accepted 21July 2010

The crystallization of gallosilicate sodalite containing halides (Cl, Br and I) in 30% ethanol have been investigated at low temperature (373 K) using one pot synthesis method. X-ray powder diffraction, IR, FAR IR, 29Si and 23Na MAS NMR, SEM and thermogravimetric data are used to characterize these sodalites. The crystal structures show cubic symmetry in a space group P3n. The crystal structures have been refined by Rietveld refinement method. The unit cell parameter, a = 8.9502, 8.9986 and 9.0779 Ĺ and the corresponding Ga-O-Si angle are found to be 134.453, 135.252 and 136.887o for chloro, bromo and iodo sodalite respectively. The MAS NMR data confirm the alternating Ga and Si ordering of sodalite framework. TGA analysis shows stability of guest anions in the sodalite framework.

Keywords: Gallosilicates, Sodalites, Crystallization

 

 

Indian Journal of Chemistry

Vol. 49A, August 2010, pp. 1052-1055

 

EDXRF determination of Dy, Eu, Gd and Sm in aqueous solutions

N K Porwal, V Natarajan*, Mithlesh Kumar, B Rajeswari, M J Kulkarni, M K Bhide, B A Dhawale &
S V Godbole

Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India

Email: vnatra@yahoo.co.in

Received 26 February 2010; revised and accepted 28 July 2010

An EDXRF technique for the determination of four important rare earth impurities, viz., Eu, Dy, Sm and Gd, at 20-1000 mg/ml in aqueous medium as well as in the presence of uranium has been reported. The conditions have been optimized for the simultaneous determination of these elements. The limits of detection for the analytes in aqueous solutions are determined to be 20 mg/ml. In order to achieve lower limits of detection, a novel method based on polyvinyl alcohol films containing these rare earths has been established. Four uranium oxide samples have been analysed by EDXRF as well as inductively coupled plasma–atomic emission spectrometry after chemical separation of uranium. The results are in good agreement.

Keywords:Analytical chemistry, EDXRF spectroscopy, Rare earths

IPC Code: Int. Cl.9 CO7F5/00; G01N21/00