Indian Journal of Chemistry

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

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VOLUME 49A

NUMBER 1

January 2010

CONTENTS

 

9

 

XPS and IR spectral studies on the structure
of phosphate and sulphate modified titania
A combined DFT and experimental study

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

K Joseph Antony Raj, R Shanmugam,
R Mahalakshmi & B Viswanathan*

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The structures of phosphated titania and sulphated titania are studied with a combined approach using DFT/B3LYP/Lanl2DZ and experimental studies such as XRD, XPS, and DRIFT spectra. The infrared absorptions, Mulliken charges, bond lengths, and dipole moments are investigated for the phosphated and sulphated titania structures optimized by DFT calculations. The XRD patterns obtained for both the modified titania show that the as-synthesized materials are amorphous in nature. The DRIFT spectra show the presence of bidentate complex in both sulphated titania and phosphated titania. The XPS data show the presence of Ti-O-S and Ti-O-P linkages in sulphated titania and phosphated titania respectively. The evaluation of IR absorptions obtained by DFT and DRIFT spectra reveal the most favorable structure of bridged bidentate for sulphated titania and a combination of monodentate and chelating bidentate for phosphated titania.

 

 

 

 

 

18

 

Investigation of electronic structures of model polypeptide chains using genetic algorithm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vinita Arora & A K Bakhshi*

 

 

 

 

The application of genetic algorithm for the investigation of electronic structures of aperiodic model polypeptide chains, first at the ab initio Hartree-Fock level and subsequently at the quasi particle band structure level, is illustrated. The calculations have been performed using Clementi’s basis sets and the effects of both minimal and double zeta basis sets, as well as the effect of change of secondary structure of the polypeptide chains, viz., the α-helix and β-pleated sheet structures, on the band gap values have been studied. Optimal compositions of the most conducting polypeptide chain returned by genetic algorithm are found to be in good agreement with the results obtained from systematic search.

 

 

26

 

Electrochemical investigations of prednisone using fullerene-C60-modified edge plane pyrolytic graphite electrode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rajendra N Goyal*, Sudhanshu P Singh, Sanghamitra Chatterjee & Sunita Bishnoi

 

 

 

 

Electrochemical investigation of prednisone has been carried out in phosphate buffer media using fullerene-C60-modified edge plane pyrolytic graphite electrode. The fullerene modified electrode shows excellent improvement in peak current and marked lowering in peak potential as compared to some other substrates. Voltammetric response of prednisone at acid treated (purified and super-purified) and untreated fullerene modified electrode shows that the enhanced reduction peak current is more prominent at the untreated fullerene modified electrode. The detection limit and sensitivity of prednisone have been found to be 4.8 × 10-8 M and 0.2766 µA µM-1 respectively.

 

 

 

 

34

 

Monoorganobismuth(III) thiocarboxylates: Synthesis, characterization and crystal structures of

[PhBi(SOCR)2] (R = Me or Ph)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Kamal R Chaudhari, Amey P Wadawale,
Vimal K Jain*, Neelam Yadav & Rakesh Bohra

 

 

 

Syntheses and structures of monoorganobismuth thiocarboxylates, [R'Bi(SOCR)2] [R' = Me, Ph; R = Me or Ph], have been described. The complexes are associated in the solid state acquiring either pentagonal bipyramidal (when R = Me) or distorted octahedral (when R = Ph) configuration around the bismuth atom.

 

 

 

Notes

 

39

 

Synthesis and crystal structure of a triprotonated decavanadate, [(C6H5CH2)(CH3)3N]3[H3V10O28].3H2O

 

 

 

 

 

 

 

 

 

 

 

 

 

Anindita Dewan, Dilip K Kakati & Birinchi K Das*

 

 

 

 

The triprotonated decavanadate anions in [(C6H5CH2)(CH3)3N]3[H3V10O28].3H2O form zigzag infinite chains via hydrogen bonds. Each [H3V10O28]3- anion forms six hydrogen bonds to two other adjacent anions in a (4+2) fashion. The O-H...O hydrogen bonds between the polyoxovanadate cages lead to the formation of unprecedented zigzag chains for [(C6H5CH2)(CH3)3N]3[H3V10O28] in the crystalline state.

 

 

 

45

 

Synthesis and novel fluorescence phenomenon of terbium(III) complex with N, N′, N″-tris (2-benz-imidazolmethyl) amine

 

 

 

 

 

 

 

Tianlin Yang*, Min Gao, Wenwu Qin & Jinhui Yang

 

 

 

 

A benzimidazole ligand with a tripodal structure, N, N′, N″-tris (2-benzimidazolmethyl) amine and its terbium(III) complex has been synthesized. The terbium ion is found to coordinate with the nitrogen atoms of imidazole ring and the bridgehead nitrogen atom. The luminescence of terbium complex in aqueous solutions is strongly enhanced by H+ concentration. Fluorescence enhancement on protonation of the nitrogen atoms of imidazole ring is due to the suppressed photoinduced electron transfer fluorescence quenching on addition of acid.

 

49

 

Chemoselective hydrogenation of crotonaldehyde to crotyl alcohol over Pt/CexSm1-xO2-δ catalysts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ling-Yun Jin, Li-Ping Tao, Xi-Jing Liu,
Guan-Qun Xie, Ji-Qing Lu & Meng-Fei Luo*

 

 

 

Pt/CexSm1-xO2-δ catalysts have been prepared by impregnation method using H2PtCl6 as precursor. Sm promotes the selective hydrogenation of C=O bond to crotyl alcohol due to formation of strong Lewis acidic sites. For Pt/Ce0.8Sm0.2O2-δ catalysts, with increasing reduction temperatures, the crotonaldehyde conversion decreases while the selectivity to crotyl alcohol increases. Also, during the reaction process there is carbon deposition on the catalyst surface, which results in decrease in the catalytic activity as well as selectivity.

 

 

 

54

 

 

Undoped, single phase barite BaCrO4
photocatalyst for the degradation of methylene blue under visible light

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sanjay R Thakare*, S R Patil & M D Choudhari

 

 

 

Photoassisted degradation of methylene blue has been carried out in aqueous dispersions under visible irradiation at wavelengths greater than 400 nm with BaCrO4 and bare TiO2. Spectral changes suggest that the demethylation is an initiation process of photocatalysis reaction followed by ring opening and finally mineralisation into mineral acid and water. BaCrO4 is a better photocatalyst than bare TiO2 under visible light irradiation.

 

 

 

Authors for correspondence are indicated by (*)

 

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 9-17

 

XPS and IR spectral studies on the structure of phosphate and sulphate modified titania – A combined DFT and experimental study

K Joseph Antony Raja, R Shanmugamb, R Mahalakshmib & B Viswanathana, *

aNational Centre for Catalysis Research, Indian Institute of Technology Madras, Chennai 600 036, India

Email: bvnathan@iitm.ac.in

bPG & Research Department of Chemistry, Thiagarajar College, Madurai 625 009, India

Received 30 October 2009; revised and accepted 14 December 2009

The structures of phosphated titania and sulphated titania are studied with a combined approach using DFT/B3LYP/Lanl2DZ and experimental studies such as XRD, XPS, and DRIFT spectra. The infrared absorptions, Mulliken charges, bond lengths, and dipole moments are investigated for the phosphated and sulphated titania structures optimized by DFT calculations. The XRD patterns obtained for both the modified titania show that the as-synthesized materials are amorphous in nature. The DRIFT spectra show the presence of bidentate complex in both sulphated and phosphated titania. The XPS data show the presence of Ti-O-S and Ti-O-P linkages in sulphated and phosphated titania respectively. The evaluation of IR absorptions obtained by DFT and DRIFT spectra reveal the most favorable structure of bridged bidentate for sulphated titania and a combination of monodentate and chelating bidentate for phosphated titania.

Keywords: Theoretical chemistry, Density functional calculations, Catalysts, Spectral studies, X-ray diffraction, X-ray photoelectron spectroscopy, DRIFT spectroscopy, Titania, Phosphated titania, Sulphated titania

         IPC Code: Int. Cl.9 B01J21/00

 

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 18-25

 

Investigation of electronic structures of model polypeptide chains
using genetic algorithm

Vinita Arora & A K Bakhshi*

Department of Chemistry, University of Delhi, Delhi 110 007, India

Email: akbakhshi2000@yahoo.com

Received 20 October 2009; revised and accepted 22 December 2009

The applications of genetic algorithm towards the investigation of electronic structures of aperiodic model polypeptide chains, first at the ab initio Hartree-Fock level and subsequently at the quasi particle band structure level are illustrated. The calculations have been performed using Clementi’s basis sets and the effects of both minimal and double zeta basis sets, as well as the effect of change of secondary structure of the polypeptide chains, viz., the α-helix and β-pleated sheet structures on the band gap values have been studied. The effects of electron correlation and hydration on density of states of model polypeptide chains containing glycine and alanine units have also been investigated. Optimal compositions of the most conducting polypeptide chain returned by genetic algorithm are found to be in good agreement with the results obtained from systematic search.

          Keywords: Theoretical chemistry, Genetic algorithms, Electronic structures, Polypeptides

 

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 26-33

 

 

Electrochemical investigations of prednisone using fullerene-C60-modified edge plane pyrolytic graphite electrode

Rajendra N Goyal*, Sudhanshu P Singh, Sanghamitra Chatterjee & Sunita Bishnoi

Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, India

Email: rngcyfcy@iitr.ernet.in

Received 5 November 2009; accepted 15 December 2009

Electrochemical investigation of prednisone has been carried out in phosphate buffer media using fullerene-C60-modified edge plane pyrolytic graphite electrode. The reduction occurs as a single well-defined pH dependent peak. The fullerene modified electrode shows excellent improvement in peak current and marked lowering in peak potential as compared to the various substrates such as fullerene modified glassy carbon electrode and indium tin oxide, gold and basal plane pyrolytic graphite electrodes. A comparative study of the voltammetric response of prednisone at acid treated (purified and super-purified) and untreated fullerene modified electrode shows that the enhanced reduction peak current is more prominent at the untreated fullerene modified electrode. The product corresponding to 2e, 2H+ reduction has been isolated and characterized. The detection limit and sensitivity of prednisone have been found to be 4.8 × 10-8 M and 0.2766 µA µM-1 respectively. The practical application of the studies is demonstrated by the determination of prednisone in real samples and good agreement with results obtained by HPLC is observed.

Keywords:   Electrochemistry, Prednisone, Edge plane pyrolytic graphite electrode, Fullerene,

                     Embedded metallic impurities

           IPC Code: Int. Cl.9 G01N27/00

 

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 34-38

 

Monoorganobismuth(III) thiocarboxylates: Synthesis, characterization and crystal structures of [PhBi(SOCR)2] (R = Ph or Me)

Kamal R Chaudharia, Amey P Wadawalea, Vimal K Jaina, *, Neelam Yadavb & Rakesh Bohrab

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

Email: jainvk@barc.gov.in

bDepartment of Chemistry, Rajasthan University, Jaipur 302 004, India

Email: rkbohra@sifymail.com

Received 3 September 2009; revsied and accepted 11 December 2009

The reactions of methylbismuth dichloride in the presence of triethylamine and triphenylbismuth with thiocarboxylic acids, RC(O)SH (R = Ph or Me) in 1:2 ratio in benzene affords monoorganobismuth thiocarboxylates, [R’Bi(SOCR)2] [R’ = Me, Ph; R = Ph or Me]. These complexes have been characterized by elemental analyses and NMR (1H, 13C{1H}) spectroscopy. Molecular structures of [PhBi(SOCR)2] [R = Ph or Me] have been established by single crystal X-ray analyses. The complexes are associated in the solid state acquiring either pentagonal bipyramidal (when R = Me) or distorted octahedral (when R = Ph) configuration around bismuth atom.

Keywords: Coordination chemistry, X-ray structure, Bismuth, Carboxylates

           IPC Code: Int. Cl9 C07F9/00

 

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 39-44

 

Synthesis and crystal structure of a triprotonated decavanadate, [(C6H5CH2)(CH3)3N]3[H3V10O28].3H2O

Anindita Dewan, Dilip K Kakati & Birinchi K Das*

Department of Chemistry, Gauhati University
Guwahati 781 014, Assam, India

Email: Birinchi.Das@hotmail.com

Received 26 October 2009; accepted 18 December 2009

The title compound, [(C6H5CH2)(CH3)3N]3[H3V10O28].3H2O, has been obtained by treating V2O5 with H2O2 in presence of benzyltrimethylammonium chloride and characterised. The crystal structure of the compound has been determined. The protonation sites on the cage surface of the decavanadate [H3V10O28]3- anion have been clearly identified. Intermolecular O-H...O hydrogen bonds involving the surface protons leads to the formation of an unprecedented zigzag chain of the [H3V10O28]3- anions.

          Keywords: Coordination chemistry, Supramolecular chemistry, Polyoxometallates, Triprotonated decavanadate, Protonated compounds, Hydrogen-bonded chains, X-ray diffraction, Crystal          structure, Vanadium

        IPC Code: Int. Cl.9 C07F9/00

 

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 45-48

 

Synthesis and novel fluorescence phenomenon of terbium(III) complex with N, N′, N″-tris (2-benzimidazolmethyl) amine

Tianlin Yanga, *, Min Gaoa, Wenwu Qinb & Jinhui Yanga

aKey Laboratory of Energy Sources and Chemical Engineering, College of Chemistry and Chemical Engineering,
Ningxia University, Yinchuan, 750021, PR China

Email: yang_tl@nxu.edu.cn

bKey Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, PR China

Received 27 October 2009; revised and accepted 17 December 2009

A benzimidazole ligand with a tripodal structure, N, N′, N″-tris (2-benzimidazolmethyl) amine, and its terbium (Ⅲ) complex has been synthesized. The complex has been characterized by element analysis, IR spectra, mass spectra, thermal analysis and molar conductivity. The terbium ion is found to coordinate with the nitrogen atoms=N-of imidazole ring and the bridgehead nitrogen atom. The fluorescence properties of the complex in aqueous solutions have been studied. Under excitation of UV light, the complex exhibits characteristic fluorescence of terbium ion. The luminescence of terbium complex in aqueous solutions is strongly enhanced by H+ concentration. This phenomenon makes the new complex favorable for use in fluorescence switches and sensors. The mechanism of the fluorescence enhancement by protonation of the nitrogen atoms-NH-of imidazole ring is due to the suppressed photoinduced electron transfer fluorescence quenching on addition of acid.

Keywords: Coordination chemistry, Fluorescence, Luminescence, Terbium, Benzimidazoles

           IPC Code:  Int. Cl.9 C07B5/00; C09K11/77

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 49-53

 

Chemoselective hydrogenation of crotonaldehyde to crotyl alcohol over Pt/CexSm1-xO2-δ catalysts

Ling-Yun Jin, Li-Ping Tao, Xi-Jing Liu, Guan-Qun Xie,
Ji-Qing Lu & Meng-Fei Luo*

Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry
Zhejiang Normal University, Jinhua 321004, China

Email: mengfeiluo@zjnu.cn

Received 6 November 2009; accepted 16 December 2009

Pt/CexSm1-xO2-δ catalysts have been prepared with impregnation method using H2PtCl6 as precursor. The selective vapor-phase hydrogenation of crotonaldehyde to crotyl alcohol over the catalysts has also been studied. It is found that introduction of Sm promotes the selective hydrogenation of C=O bond to crotyl alcohol due to formation of strong Lewis acidic sites. For Pt/Ce0.8Sm0.2O2-δ catalysts, with increasing reduction temperatures, the crotonaldehyde conversion decreases while the selectivity to crotyl alcohol increases. Also, during the reaction process there is carbon deposition on the catalyst surface, which results in decrease, both in the catalytic activity as well as selectivity.

   Keywords: Catalyst, Supported catalysts, Hydrogenation, Chemoselective hydrogenation,  Selective

                     hydrogenation,  Alcohols, Unsaturated alcohols, Aldehydes, Platinum

 

       IPC Code: Int. Cl.9 B01J21/00

 

Indian Journal of Chemistry

Vol. 49A, January 2010, pp. 54-58

 

Undoped, single phase barite BaCrO4 photocatalyst for the degradation of methylene blue under visible light

 

Sanjay R Thakarea, *, S R Patilb & M D Choudharib

a Department of Chemistry, Science College, Congress Nagar, Nagpur 400 012, India

Email: sanjythakare@yahoo.co.uk

b Department of Applied Chemistry, B D College of Engineering, Seagram, Dist Wardha 442 102, India

Email: patil_subhashchandra@yahoo.co.in

Received 26 February 2009; re-revised and accepted 23 December 2009

The photoassisted degradation of a phenothiazine dye, methylene blue, has been examined in aqueous dispersions under visible irradiation at wavelengths greater than 400 nm with BaCrO4 and bare TiO2. Spectral changes during the photocatalytic degradation of methylene blue suggest that the de-methylation is an initiation process of photocatalysis reaction followed by ring opening and finally mineralisation into mineral acid and water. Comparative study shows that BaCrO4 is a better photocatalyst than bare TiO2 under visible light irradiation. COD analysis suggests that the degradation of methylene blue is due to photocatalysis and not due to any other reason. Catalytic poisoning is observed for both the photocatalysts.

         Keywords:     Photocatalysis, Degradations, Dyes, Phenothiazines, Barite, Titania, Methylene blue,

                                 Organic pollutants    

        IPC Code: Int. Cl.9 BO1J21/00; C09B