Indian Journal of Chemistry

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

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VOLUME 45A

NUMBER 10

October 2006

CONTENTS

Papers

 

2171

 

On electronic properties of model Type I conducting triblock polymeric superlattices

 

 

 

 

 

 

 

Swati Agrawal & A K Bakhshi*

 

 

 

Theoretical studies on quasi-one-dimensional model superlattices (AmBnCk)x and (AmCnBk)x belonging to Type I have been carried out using simple NFC method in tight binding approximation. Increasing the block size decreases the band gap while changing the arrangement of blocks does not alter the properties as long as the block size of components remains the same. Electronic properties depend mainly on the lowest band gap component.

 

 

 

2179

 

The quantum chemical investigation of the addition reactions of Br2 to homocubylidene-homocubane and its derivatives

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rıza Abbasoğlu* & Sevil Savaşkan Yılmaz

 

 

 

 

Geometry and the electronic structure
of homocubylidenehomocubane, (HC) trans-(1-methyl-
2-homocubyliden)-1-methylhomocubane (DMHC)
and trans-(1-tert-butyl-2-homocubyliden)-1-tert-butyl-homocubane (DBHC) and their molecular complexes with Br2 have been studied by DFT method. Results show that the double bond of HC molecule has a planar structure, those in DMHC and DBHC molecules are almost planar, while the stable configurations of the Br2 complexes have an axial structure. Also, the DMHC...Br2 complex is more stable than the HC...Br2 complex, while the DBHC...Br2 complex containing the bulky tert- butyl group has stability of sterically encumbered olefin-brom complex and it depends on the nature of ‘cage’ substituents on the double bond carbons.

 

 

2186

 

On the structure and properties of erythritol in its ground state and first excited state: A comparative theoretical study

 

 

 

 

 

 

 

 

 

 

 

 

D De, S Dalai & B R De*

 

 

 

 

Quantum mechanical gas phase study of the structure and properties of erythritol in its ground state and first excited triplet state have been carried out at the ab initio, AM1 and the hybrid B3LYP DFT level with complete geometry optimization and varying basis sets (3-21G, 6-31G, 6-31G* using GAMESS, MOPAC 6.00 and GAUSSIAN 03W). All the methods predict the carbon skeleton to be planar in the lowest excited triplet state.

 

 

2193

 

Effective synthesis of hexacoordinate silicates of 2,3-dihydroxynaphthalene under microwave condition and X-ray crystal structure of bis(tri-n-butylammonium) tris(2,3-dihydroxynaphthalato)-silicate

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A Suvitha, B Varghese, M N Sudheendra Rao,
G Sundararajan & B Viswanathan*

 

 

 

 

Tris (2,3-dihydroxynaphthalato)silicates with different ammonium counter cations have been synthesised both by conventional method and under microwave conditions using tetraethoxysilane. Single crystal X-ray structure of
[(n-C4H9)3NH)2][Si(C10H6O2)3] reveals a distorted octahedral geometry around silicon and only discrete hydrogen bonding interaction between the ion pairs.

 

 

 

 

2199

 

Photocatalytic studies over Ce1-xFexO2 for the degradation of azo dye

 

 

 

 

 

 

 

 

Pritam Borker & A V Salker*

 

 

 

 

Photocatalytic degradation of Naphthol Blue Black has been carried out over Ce1-xFexO2 in presence of sunlight. Effects of variation of different parameters like pH, amount of catalyst and presence of oxygen on the degradation rate have been studied.

 

 

2203

 

Synthesis, reactions, spectral and magnetic studies of chloro-{2-(o-hydroxyphenyl) benzimi-dazolato}-cobalt(II)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R K Dubey * & C M Mishra

 

 

 

 

A dimeric chloro bridged complex of cobalt(II),
[(m-Cl)2Co2{h2-(pbz)}2] has been prepared and characterized.

 

 

Notes

 

2209

 

Selective synthesis of acrylonitrile from acetonitrile and methanol over manganese modified Ba/ZrO2 catalysts

 

 

 

 

 

Leihong Zhao*, Mengfei Luo, Guangyu Liu,
Jie Song, Yongping Zhang & Qingbao Zhang

 

 

 

 

A series of Mn loaded catalysts based on Ba/ZrO2 have been prepared by impregnation method and characterized by XRD, CO2-TPD, SEM, XPS, and nitrogen physorption. The effects of Mn loading, reaction temperature and reaction time on the catalytic properties of BaxMny/ZrO2 catalysts for the synthesis of acrylonitrile from acetonitrile and methanol have been studied.

 

 

2215

 

Silica-supported poly-g-aminopropylsiloxane palladium (Pd2+)-transition metal (Cu2+) complex: A new catalyst system for Heck reaction

 

 

 

 

 

Shao Fen Zhao*, Ren Xian Zhou &
Xiao Ming Zheng

 

 

 

 

A new silica-supported poly-γ-aminopropylsiloxane transition metal (Cu2+) and palladium (Pd2+) catalyst has been prepared from organic silica via immobilization on fumed silica, followed by treatment with Cu(OAc)2 and PdCl2 in ethanol. The catalyst shows excellent activity for Heck arylation of aryl iodides with alkene.

 

2218

 

Kinetics and mechanism of the oxidation of some a-hydroxy acids by benzyltriethylammonium chlorochromate

 

 

 

 

 

 

 

 

 

 

 

 

 

Poonam Pohani, Anjana and & Pradeep K. Sharma*

 

 

 

 

 

 

2224

 

Synthesis, spectra, electrochemistry and single crystal X-ray structure of [Co(a-NaiEt)2(N3)2],
a-NaiEt = 1-ethyl-2-(naphthyl-a-azo)imidazole

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Debasis Banerjee & Chittaranjan Sinha*

 

 

 

 

 

 

2229

 

Solution behaviour of cetyltrimethyl-ammonium ceric nitrate(CTACN): An example of temperature-induced micellization

 

 

 

 

 

 

 

 

 

 

 

 

 

Biswa B Nayak, Mallika Panigrahi,
Sabita Patel, Sukalyan Dashb & Bijay K Mishra*a,

 

 

 

 

A temperature induced micellization has been proposed for cetyltrimethyl-ammonium ceric nitrate in aqueous medium.

 

 

2233

 

External proton-induced X-ray emission: A simple method for multi-elemental analysis of water

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P K Nayak*, T R Rautray & V Vijayan

 

 

 

 

 An accelerator based rapid method for multi-elemental analysis of water  samples has been presented using
pre-concentration  (metal ions as carbamates) techniques followed by the use of external PIXE set-up.

 

 

2238

 

Determination of trace phosphorous by energy transfer fluorescence quenching of Acridine orange-Rhodamine B

 

 

 

 

 

 

 

 

 

 

Bao-sheng Liu*, Zhi-chao Liu & Jing Gao

 

 

 

 

A new method for determination of trace phosphorous by energy transfer fluorescence quenching between Acridine orange and Rhodamine B has been developed. Effective energy transfer occurs in presence of dodecyl benzene sodium sulfonate at λexem= 450/575 nm when the fluorescence intensity of Rhodamine B increases sharply. Orthophosphate reacts with molybdate and forms molybdophosphate in hydrochloric acid medium, which diminishes the fluorescence intensity of Rhodamine B. The method is suitable for determination of phosphorous in the range of 0.05~0.70 mg l-1 with detection limit up to
15.2 µg l-1
.

 

 

2242

 

Corrigendum

 

 

 

 

Authors for correspondence are indicated by (*)

 

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2171-2178

 

On electronic properties of model Type I conducting triblock polymeric superlattices

 

Swati Agrawal & A K Bakhshi*

Received 12 July 2006; revised 25 August 2006

Theoretical studies on quasi-one-dimensional model superlattices (AmBnCk)x and (AmCnBk)x belonging to Type I have been carried out using simple NFC method in tight binding approximation. For each system, the trends in electronic properties have been studied as a function of block sizes m, n and k, composition (m:n:k) and the arrangement of blocks. Increasing the block size is found to decrease the band gap while changing the arrangement of blocks does not alter the properties as long as the block size of components remains the same. The electronic properties are found to depend mainly on the lowest band gap component. These results have also been compared with the corresponding results for periodic diblock copolymers.

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2179-2185

 

The quantum chemical investigation of the addition reactions of Br2 to homocubylidenehomocubane and its derivatives

 

Rıza Abbasoğlu* & Sevil Savaşkan Yılmaz

Received 11 April 2005; rerevised 2 August 2006

The electronic and geometric structures of homocubylidenehomocubane (HC), trans- (1-methyl-2-homocubyliden)–1–methylhomocubane (DMHC) and trans-(1-tert-butyl-2-homocubyliden)–1-tert-butylhomocubane (DBHC) molecules have been investigated by B3LYP/6-311G* method. These results agree with X-ray results and show that the double bond of HC molecule has a planar structure, while the double bonds in DMHC and DBHC molecule are almost planar. The complexes (1:1 p complexes) of the molecules with Br2 have been investigated by B3LYP/6-311+G* method and it is observed that the stable configurations have an axial structure. The electronic and the steric factors affecting the structure and the stability of the molecular complexes have been studied. It is observed that the DMHC...Br2 complex is more stable than HC...Br2 complex. The DBHC...Br2 complex containing the bulky tert-butyl group has stability of sterically encumbered olefin-brom complex and it depends on the nature of ‘cage’ substituents on the double bond carbons. The bridged bromonium cation is the more stable cation among the cationic intermediates formed in the addition reaction of bromine to HC and the reaction occurs via this cation. The nucleophilic attack by bromide ion is not sterically prevented to HC-Br+ bridged bromonium cation and as a result, normal 9, 9'-dibromide product is formed. The nucleophilic attack by bromide ion is sterically prevented to AD-Br+ bridged bromonium cation.

 

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2186-2192

On the structure and properties of erythritol in its ground state and first excited state: A comparative theoretical study

D De, S Dalai & B R De*

Received 29 October 2005; accepted 31 August 2006

Quantum mechanical gas phase study of the structure and properties of erythritol in its ground state and first excited triplet state have been carried out at the ab initio, AM1 and the hybrid B3LYP DFT level with complete geometry optimization and varying basis sets (3-21G, 6-31G, 6-31G* using GAMESS, MOPAC 6.00 and GAUSSIAN 03W) to have a first hand information of the molecule. The calculated geometry is not i-symmetry which is in complete disagreement with the observed results, which demands condensed phase calculations. All the methods predict the carbon skeleton to be planar in the lowest excited triplet state. The calculated charge density on O-atoms supports the reported experimental findings. The studies show that neutral erythritol can coordinate with various transition metal ions both in ground state and in excited triplet state, which is in excellent agreement with the experimental findings. The B3LYP-DFT using 3-21G basis set has been found to be the best in respect of reliability, computation time and agreement with some of the experimental findings.

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2193-2198

Effective synthesis of hexacoordinate silicates of
2,3-dihydroxynaphthalene under microwave condition and X-ray crystal structure of bis(tri-n-butylammonium)tris
(2,3-dihydroxynaphthalato)silicate

A Suvitha, B Varghese, M N Sudheendra Rao, G Sundararajan* & B Viswanathan *

Received 9 April 2006; revised 16 August 2006

The synthesis of tris(2,3-dihydroxynaphthalato)silicate with different ammonium counter cations has been achieved both by conventional method and under microwave conditions using tetraethoxysilane. The compounds have been characterized using elemental analysis, IR, NMR (1H, 13C and 29Si), and MALDI-TOF-MS techniques. Single crystal X-ray structure of [(n-C4H9)3NH)2][Si(C10H6O2)3] reveals a distorted octahedral geometry around silicon and only discrete hydrogen bonding interaction between the ion pairs.

IPC Code: Int. Cl.8 H05B6/64; B01J19/12

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2199-2202

 

Photocatalytic studies over Ce1-xFexO2 for the degradation of azo dye

Pritam Borker & A V Salker*

Received 9 February 2005; revised 5 August 2006

Photocatalytic degradation of textile diazo dye Naphthol Blue Black with Ce1-xFexO2 (x = 0, 0.1, 0.2, 0.3 and 1.0) has been carried out in presence of sunlight. The effects of variation of different parameters like pH, amount of catalyst, presence of oxygen, etc., on the rate of degradation of dye have been studied. Solid state properties such as surface area, magnetic susceptibility, ESR and electrical resistivity have been correlated with the photocatalytic activities.

IPC Code: Int. Cl.8 C09B; G01N21/00

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2203-2208

 

Synthesis, reactions, spectral and magnetic studies of chloro-{2-(o-hydroxyphenyl)-benzimidazolato}-cobalt (II)

R K Dubey * & C M Mishra

Received 30 January 2006; revised 24 July 2006

A new and novel (chloro) complex of cobalt (II), [(m-Cl)2Co2{h2-(pbz)}2], (1) where pbz={2-(o-hydroxyphenyl)} benzimidazole, h2 = number of connectivity sites involved in bounding the metal, has been synthesized quantitatively by the interaction of an aqueous ethanolic solution of cobalt(II) chloride with hot ethanolic solution of {2-(o–hydroxyphenyl)} benzimidazole, (pbzH) in equimolar ratio. This derivative is insoluble in common organic solvents and can form adduct, when treated with tetrahydrofuran. Further, complex 1 upon treating with sodium salts of Schiff bases, Na(smab) and Na(sap), alkoxo Na (OPri)], aryloxo Na(OAr) and tetraisopropoxyaluminate Na{Al(OPri)}4 in equimolar ratio in benzene/THF medium, produces derivatives of the types: [{h2-(smab)} Co{h2-(pbz)}] 2, [(sap) Co{h2-(pbz)}]3, [(m-OPri)2Co2 {h2-(pbz)}2] 4, [(m-OAr)2 Co2 {h2-(pbz)}2] 5, and [(m-OPri)2 {Al(OPri)2} Co {h2-(pbz)}] 6. All these complexes have been characterized by elemental analysis, IR, UV-vis, FAB-mass and magnetic studies to explore the possibility of structural elucidations.

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

 

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2209-2214

 

Selective synthesis of acrylonitrile from acetonitrile and methanol over manganese modified Ba/ZrO2 catalysts

Leihong Zhao*, Mengfei Luo, Guangyu Liu, Jie Song, Yongping Zhang & Qingbao Zhang

Received 23 January 2006; revised 26 August 2006

A series of different Mn loaded catalysts based on Ba/ZrO2 have been prepared by impregnation methods and characterized by XRD, CO2-TPD, SEM, XPS, and nitrogen physorption. Compared with the Ba0.5/ZrO2 catalyst, the manganese modified Ba0.5/ZrO2 has a BaMnO3 phase, a similar surface area, more basicity and smaller particle size. For the synthesis of acrylonitrile from acetonitrile and methanol, the effects of Mn loading, reaction temperature and reaction time on the catalytic properties of BaxMny/ZrO2 have been studied. At the optimum reaction conditions, the conversion of acetonitrile and selectivity of acrylonitrile are 14.7% and 93.8%, respectively.

IPC Code: Int. Cl.8 B01J23/34; C07C255/08

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2215-2217

 

Silica-supported poly-g-aminopropylsiloxane palladium (Pd2+)-transition metal (Cu2+) complex: A new catalyst system for Heck reaction

Shao Fen Zhao *, Ren Xian Zhou & Xiao Ming Zheng

 

Received 6 January 2006; revised 25 July 2006

A new silica-supported poly-γ-aminopropysiloxane transition metal (Cu2+) and palladium (Pd2+) catalyst has been prepared from organic silica via immobilization on fumed silica, followed by treatment with Cu(OAc)2 and PdCl2 in ethanol. The catalyst is efficient for Heck arylation of aryl iodides with alkene. The effects of reaction temperature and Pd2+ content on catalytic properties have also been studied. Pd2+ has been found to improve the catalytic performance, reducing the reaction temperature (70°C) and the induction period. It provides an economic way to synthesize unsymmetrical trans-stilbenes.

IPC Code: Int. Cl.8 B01J37/00; B01J23/44; B01J23/72

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2218-2223

 

Kinetics and mechanism of the oxidation of some a-hydroxy acids by
benzyltriethylammonium chlorochromate

Poonam Pohani, Anjana and & Pradeep K. Sharma*

Received 27 January 2006; revised 4 August 2006

The oxidation of glycollic, lactic, malic and a few substituted mandelic acids by benzyltriethylammonium chlorochromate (BTEACC) in dimethyl sulphoxide (DMSO) leads to the formation of the corresponding oxoacids. The reaction is first order each in BTEACC. Michaelis-Menten type of kinetics is observed with respect to the hydroxy acids. Reaction failed to induce pPolymerisation of acrylonitrile is not induced in this reaction. The oxidation of a‑deuteriomandelic acid showsed primary kinetic isotope effect (kH/kD = 5.51 at 298 K). The reaction does not exhibit the solvent isotope effect. The reaction is catalysed by hydrogen ions. and The hydrogen ion dependence has the form: kobs = a + b [H+]. Oxidation of p-methyl mandelic acid has been studied in 19 different organic solvents. The solvent effect has been analysed by using Kamlet’s and Swain’s multiparametric equations. A mechanism involving a hydride ion transfer via a chromate ester is proposed.

IPC Code: Int. Cl.8 C07B33/00

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2224-2228

 

Synthesis, spectra, electrochemistry and single crystal X-ray structure of [Co(a-NaiEt)2(N3)2], a-NaiEt = 1-ethyl-2-(naphthyl-a-azo)imidazole

Debasis Banerjee & Chittaranjan Sinha*

Received 12 May 2006; revised 25 August 2006

Reaction of 1-alkyl-2-(naphthyl-a-azo)imidazoles [a-NaiR, (1) where R = Me (a), Et (b), Bz (c)] with cobalt(II) acetate and NaN3 in methanol solution results in bis-chelated, azido complex, [Co(a-NaiR)2(N3)2] (2). The X-ray structure shows distorted octahedral CoN6 coordination sphere with trans-trans-trans (ttt) 2b with reference to sequence of coordination pairs of azido-N, azo-N and imidazole-N. The structure is a first example of ttt type configuration in 3d metal complexes of azoimine function. Redox properties of the complexes have been examined by cyclic voltammetry and show high potential Co(III)/Co(II) couple along with ligand reductions.

IPC Code: Int. Cl.8 C07F15/06

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2229-2232

 

Solution behaviour of cetyltrimethyl-ammonium ceric nitrate(CTACN): An example of temperature-induced micellization

Biswa B Nayak, Mallika Panigrahi, Sabita Patel, Sukalyan Dash & Bijay K Mishra *a,

Received 27 February 2006; revised 21 August 2006

Conductance, viscosity, surface tension and density of the aqueous solution of cetyltrimethylammonium ceric nitrate (CTACN) have been measured at different temperatures. and sSurface excess concentration, apparent molar volume, and degree of association have been calculated. An increased ionic association with increasing temperature has been observed. It This is attributed to a temperature induced micellization phenomenon. The resultant thermodynamic parameters derived from specific conductance also support the micellization process, wherein the dissociation of large ceric counter ion assists the aggregation.

IPC Code: Int. Cl.8 G01N9/00; G01N11/00; G01N13/02

Indian Journal of Chemistry
Vol. 45A, October 2006, pp. 2233-2237

 

External proton-induced X-ray emission: A simple method for multi-elemental analysis of water

P K Nayak*, T R Rautray & V Vijayan

Received 25 November 2004; rerevised 25 July 2006

An accelerator based rapid method for multi-elemental analysis of water samples has been presented using pre-concentration (metal ion as carbamates) technique followed by the use of external PIXE set-up. The problems regarding time required in creating vacuum and the irradiation of number of specimens (usually four to six numbers in a single run) in conventional vacuum-PIXE technique has been successfully overcome. The method is expected to be useful for multi-elemental analysis of various liquid samples on routine basis.

IPC Code: Int. Cl.8 G01N23/221

Indian Journal of Chemistry

Vol. 45A, October 2006, pp. 2238-2241

Determination of trace phosphorous by energy transfer fluorescence quenching of Acridine orange-Rhodamine B

Bao-sheng Liu*, Zhi-chao Liu & Jing Gao

Received 7 September 2005; revised 4 September 2006

A new method for determination of trace phosphorous by energy transfer fluorescence quenching between Acridine orange and Rhodamine B has been developed. Effective energy transfer occurs between the two in presence of dodecyl benzene sodium sulfonate at λexem= 450/575 nm and the fluorescence intensity of Rhodamine B increases sharply. Orthophosphate reacts with molybdate and forms molybdophosphate in hydrochloric acid medium, which diminishes the fluorescence intensity of Rhodamine B. The detection limit is up to 15.2 µg l-1. The method is suitable for determination of phosphorous in the range, 0.05~0.70mg l-1 and relative standard deviation is 1.75–3.12%. The recovery of phosphorous is 95.1~112.3%. The method has been applied to the determination of phosphorous in soil samples with satisfactory results.

IPC Code: Int. Cl.8 G01N21/64; C09B