Indian Journal of Chemistry

Total visitors: 2,164      since 13-02-08

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

 

VOLUME 46A

NUMBER 12

December 2007

 

CONTENTS

 

 

1911

 

Theoretical studies on stable geometries of C78O6 based on C2v-C78

 

 

 

 

 

 

 

 

 

 

 

 

W Zhang, S Wu* & X Wen

 

 

 

 

Semi-empirical AM1 and INDO/CIS methods as well as density function theory have been used to study equilibrium geometries and spectroscopic properties of the possible isomers of C78O6 based on C2v-C78. The most stable geometry at the ground state of C78O6 is found to be 28, 29, 30, 31, 52, 53, 70, 71, 73, 78, 75, 76C78O6 (A).

 

 

1917

 

Electrochemical study on effect of colloidal Au on horseradish peroxidase in polypyrrole layer at prussian blue modified electrode

 

 

 

 

 

 

Yingju Liu*, Qiaoyi Hu & Bimin Lin

 

 

 

 

PPY/HRP/PB and PPY/HRP/PB/Au-colloid biosensors show a linear response to H2O2. Colloidal gold is found to enhance the current response of H2O2. The possible mechanism for this enhancement has been proposed by the electrochemical electrode reaction and enzyme reaction.

 

 

1923

 

Electrochemical characterization of composite films of polypyrrole and La1-xSrxCoO3 (0 ≤ x ≤ 0.4) for electrocatalysis of O2 reduction

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R N Singh*, M Malviya & Anindita

 

 

 

 

Sandwich-type composite films of polypyrrole and La1-xSrxCoO3 (0 ≤x≤0.4) on a conductive graphite support have been
obtained by electropolymerization for electrocatalysis of the oxygen reduction reaction. Amongst the composite electrodes studied, the G/PPy/PPy(La0.8Sr0.2CoO3)/PPy electrode in
0.5 mol dm-3 K2SO4 + 5 mmol dm-3 KOH at 25C exhibits the highest electrocatalytic activity towards the oxygen reduction reaction.

 

1929

 

Physicochemical behaviour of copper(II) complexes of chelated diamine ligands: Catalytic role of diaquabis(ethylenediamine)copper(II) perchlorate in acylal formation

 

 

 

 

P Sarmah, S Singha, R Chakrabarty, S J Bora & Birinchi K Das*

 

 

 

 

Synthesis and properties of a few copper(II) complexes containing ethylenediamine ligands are reported. [Cu(en)2(H2O)2](ClO4)2 shows good catalytic activity in acylal formation from aromatic aldehydes.

 

 

 

 

 

 

 

1938

 

Synthesis, physicochemical characterisation and chemical properties of the first nonaalkoxo-distannates and dititanates of nickel(II)

 

 

 

 

 

 

 

 

 

Neetu Agrawal & Anirudh Singh*

 

 

 

 

Heterobimetallic alkoxides of the types [Ni{M2(OR)9(m-Cl)}]2 and [Ni{M2(OR)9}2] (where M = Sn, Ti; R = Pri, Et) have been prepared by the reactions of NiCl2.xROH (R = Pri, Et) with M{M2(OR)9} (M = Na, K) in 1:1 and 1:2 molar ratios in benzene, respectively.

 

 

Notes

 

1947

 

Synthesis and crystal structure of an iron(II) dimeric complex

 

 

 

 

 

 

 

 

 

 

 

 

 

Partha Roy, Koushik Dhara, Jishnunil Chakraborty, Munirathinam Nethaji & Pradyot Banerjee*

 

 

 

 

An iron(II) complex, [Fe2(salen)2] [salen = N,N'-ethylenebis(salicylideneiminato) dianion], has been prepared and characterized by FT-IR, UV-vis spectra, thermogravimetric analysis, cyclic voltammetry and X-ray crystallography. The structural study reveals that it is a penta-coordinate Fe(II) dimeric complex.

 

 

 

1951

 

Preparation and characterization of the lanthanide complex Eu(TTA)3phen/vinyl pyrrolidone luminescent nanofiber by electrospinning

 

 

 

 

 

Liu Wei* & Wang Ce

 

 

 

Eu(TTA)3phen/vinyl pyrrolidone composite nanofibers have been prepared by electrospinning technique. The excitation of Eu(TTA)3phen/PVP systems by UV light results in a ligand-to-metal energy transfer and the emission spectra display characteristic luminescence of the central ions (5D0 7F2 for Eu3+). Photoluminescence measurements show that Eu(TTA)3phen/PVP nanofibers have higher intensity and longer lifetime than that of Eu(TTA)3phen powders.

 

1955

 

Preparation of silica nanoparticle through coating with octyldecyltrimethoxy silane

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N Venkatathri

 

 

 

 

Silica nanoparticles have been prepared using tetraethylorthosilicate, water, aqueous ammonia, ethanol and octadecyltrimethoxy silane as constituents. The sample is amorphous with surface area of 93.54 m2/g and contains Q2, Q3 and Q4 species. TEM reveals the particles to be core shell type which is absent in octadecyltrimethoxy silane-free samples. The samples show Si-O-Si tetrahedral skeletal vibrations.

 

 

 

 

1959

 

Synthesis and crystal structure of the zinc(II) complex of 5-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-ylhydrazono) hexahydropyrimidine-2-thioxo-4,5,6-trione

 

 

 

 

 

 

 

 

 

 

 

 

V Sadasivan & M Alaudeen*

 

 

 

 

 

 

1963

 

Complexes of ruthenium(III), rhodium(III) and iridium(III) with ligands bearing 2,6-diacetylpyridine bis(S-alkylisothiosemicarbazones): Synthesis, spectral studies and structural elucidation

 

 

 

 

 

 

 

 

 

 

 

 

 

Vinod K Sharma* & Ankita Srivastava

 

 

 

 

 

 

 

1969

 

Kinetics and mechanism of visible light induced oxidation of hydrazine by peroxodisulphate in aqueous solution containing tris-(2,2-bipyridine) ruthenium(II)

 

 

 

 

 

 

 

Savita Bansal, N K Soni, C L Khandelwal & P D Sharma*

 

 

 

 

The rate of visible light induced oxidation of hydrazine by peroxodisulphate in the presence of tris-(2,2-bipyridine)-ruthenium(II) [Ru(bipy)32+] in aqueous solution is independent of the substrate concentration but increases with the intensity of light absorbed.

 

 

1972

 

Excess transport properties of binary mixtures of methanol and pyridine through ultrasonic measurements at different temperatures

 

 

 

 

 

 

 

 

 

G V Rama Rao, A Viswanatha Sarma,
D Ramachandran & C Rambabu *

 

 

 

The viscosities, densities and ultrasonic velocities of binary liquid mixtures of methanol with piperidine and morpholine and pyridine with piperidine and morpholine have been determined at 303.15-318.15K over the entire composition range. These data have been utilized to estimate the excess free volume, excess internal pressure, excess enthalpy, excess velocity, excess acoustic impedance and excess Gibbs free energy of activation of flow. Results indicate that there are intermolecular interactions among components of the binary mixtures that lead to possible hydrogen bond formation (of the type NH-O) between unlike molecules.

 

 

1979

 

Annual Index

 

 

 

 

 

Authors for correspondence are indicated by (*)


 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1911-1916

 

Theoretical studies on stable geometries of C78O6 based on C2v-C78

W Zhang,, S Wu* & X Wen

Received 20 June 2007; revised 29 September 2007

The semi-empirical AM1 and INDO/CIS methods as well as density function theory have been used to study equilibrium geometries and spectroscopic properties of the possible isomers of C78O6 based on C2v-C78. The most stable geometry at the ground state of C78O6 is found to be 28, 29, 30, 31, 52, 53, 70, 71, 73, 78, 75, 76-C78O6 (A). TheC(70)-C(71) and C(75)-C(76) bonds are opened up to form annulene-like structures, whereas the other four bonds are not broken and show epoxy features in C78O6 (A). The oxygen atoms added tend to approach the sites vacated by the previous oxygen atoms since the conjugation system in C2v-C78 is destroyed at these sites. Based on the B3LYP/6-31G optimized geometries, the main absorptions in the electronic spectra and the stretching vibrations of the C=C bonds in the IR spectra of C78O6 isomers are blue shifted as compared with those of C2v-C78 calculated using the INDO/CIS and AM1 method, respectively. The chemical shifts of the carbon atoms in the epoxy and annulene-type structures of C78O6 isomers, calculated at B3LYP/6-31G level, move upfield.

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1917-1922

 

Electrochemical study on effect of colloidal Au on horseradish peroxidase in polypyrrole layer at prussian blue modified electrode

Yingju Liu, *, Qiaoyi Hu & Bimin Lin

Received 12 November 2006; revised 12 October 2007

Cyclic voltammetry and current-time curve have been used to investigate the Au-colloid function on the horseradish peroxidase biosensor response. Firstly Prussian blue is deposited on the electrode, and then the polypyrrole (PPY)/HRP biosensor is constructed by electrochemical oxidization of pyrrole in the solution containing horseradish peroxidase and pyrrole.. The colloidal Au is then immobilized on the electrode. Cyclic voltammograms show higher current in the presence of Au-colloid as compared to that in the absence of the colloid. The PB/PPY/HRP and PB/PPY/HRP/Au-colloid biosensors exhibit linear current-time response to hydrogen peroxide over a concentration range of 210-6 M 1.810-4 M. , Michaelis-Menten constants of the two biosensors are 0.63 and 0.35 mM, respectively. The dependence of current responses on applied voltage has been discussed, and the mechanism has been proposed. The results show that colloidal Au enhances the current response and decreases the energy -barrier of electron transfer reaction on the electrode. The interference of foreign substances has also discussed.

IPC Code: Int. Cl.8 B01J; C25B3/02

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1923-1928

 

Electrochemical characterization of composite films of polypyrrole and La1-xSrxCoO3 (0 ≤ x ≤ 0.4) for electrocatalysis of O2 reduction

R N Singh*, M Malviya & Anindita

Received 18 April 2007; revised 22 October 2007

Sandwich-type composite films of polypyrrole (PPy) and La1-xSrxCoO3 (0 ≤x≤0.4) on a conductive graphite support (G) have been obtained by electropolymerization for electrocatalysis of the oxygen reduction reaction (ORR). The composite films have been characterized by SEM, EDAX, cyclic voltammetry, impedance and Tafel polarization techniques. The studies show that the composite electrodes are greatly active for the ORR than the non-composite one. The higher Sr substitutions (>0.2 mol) have an adverse effect on the electrocatalytic activity. The rate for the ORR at the composite film has been found to decrease with decreasing pH of the electrolyte. Among all the four composite electrodes studied, the G/PPy/PPy(La0.8Sr0.2CoO3)/PPy electrode in 0.5 mol dm-3 K2SO4 plus 5 m moldm-3 KOH at 25C exhibits the highest electrocatalytic activity towards the ORR.

IPC Code: Int. Cl.8 B01J23/00; C25D

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1929-1937

 

Physicochemical behaviour of copper(II) complexes of chelated diamine ligands: Catalytic role of diaquabis(ethylenediamine)copper(II) perchlorate in acylal formation

Purabi Sarmah, Sunita Singha, Rajesh Chakrabarty, Sanchay J Bora & Birinchi K Das*

Received 18 September 2007; revised 2 November 2007

Preparation and properties of a few chelated diamine complexes of copper(II) are reported. The compounds, [Cu(en)2(H2O)2](ClO4)2 (1), [Cu(tmen)2(H2O)2](ClO4)2 (2), [Cu2(en)2Cl4]n (3) and [Cu2(en)2(SO4)2(H2O)4].2H2O (4) have been prepared in moderate to excellent yields and characterized by various physicochemical techniques. The structure of [Cu2(en)2Cl4]n (3) has been determined by single crystal X-ray diffraction. Complex 3 crystallizes in monoclinic space group P21/m, with unit cell parameters a = 6.7850 (14) , b = 5.7600(12), c = 8.2240(16), b = 93.75(3), V = 320.7(1)3. The structure has been solved by direct method and refined by full-matrix least squares to final R1 = 0.0460, wR2 = 0.1249 and GooF = 1.135 for all 818 reflections. Each copper atom in complex 3 is present in a distorted octahedral environment created by a chelating ethylenediamine ligand and four chlorine atoms. Two adjacent parallel CuClCu chains joined by short CuCl bonds give rise to a zigzag ribbon-like polymer. Complex 1 has been studied as a catalyst for the conversion of aromatic aldehydes to acylals under solvent-free conditions at room temperature.

IPC Code: Int. Cl.8 C07F1/08

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1938-1946

 

Synthesis, physicochemical characterisation and chemical properties of the first nonaalkoxo-distannates and dititanates of nickel(II)

Neetu Agrawal & Anirudh Singh*

Received 2 May 2007; revised 24 October 2007

Heterobimetallic alkoxides of the types [Ni{M2(OR)9(m-Cl)}]2 (1)-(4)and [Ni{M2(OR)9}2] (5)-(8) (where M = Sn, Ti; R = Pri, Et) have been prepared by the reactions of NiCl2.xROH (R = Pri, Et) with M{M2(OR)9} (M = Na, K) in 1:1 and 1:2 molar ratios in benzene, respectively. The chloro complexes (1)-(4) on reactions with appropriate alkali metal alkoxides yield alkoxo analogues: [Ni{Sn2(OPri)9}(m-OPri)]2 (10), [Ni{Sn2(OEt)9}(m-OEt)]2 (11), [Ni{Ti2(OPri)9}(m-OPri)]2 (12), [Ni{Ti2(OEt)9}(m-OEt)]2 (13), [Ni{Sn2(OPri)9}(m-OCH2CH2OCH3)]2 (14), [Ni{Sn2(OEt)9}(m-OCH2CH2 OCH3)]2 (15), [Ni{Sn2(OPri)9} (m-OCH2CH2OC2H5)]2 (16), [Ni{Sn2(OEt)9}(m-OCH2CH2OC2H5)]2 (17), [Ni{Sn2 (OPri)9}(m-OCH2CH2NHCH3)]2 (18), and [Ni{Sn2(OEt)9}(m-OCH2CH2NHCH3)]2 (19). All these complexes have been characterized by elemental analyses, spectroscopic (UV-vis, and IR) and magnetic studies as well as by molecular weight measurements.

IPC Code: Int. Cl.8 C0F15/04

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1947-1950

 

Synthesis and crystal structure of an iron(II) dimeric complex

Partha Roy, Koushik Dhara, Jishnunil Chakraborty, Munirathinam Nethaji & Pradyot Banerjee*

Received 27 July 2007; accepted 30 October 2007

An iron(II) complex, [Fe2(salen)2] has been prepared by the reaction of [FeIII(salen)Cl] with copper(II) malonate dihydrate [salen = N,N-ethylenebis(salicylideneiminato) dianion] in N,N-dimethylformamide-water mixture. The complex has been characterized by FT-IR spectroscopy, UV-vis spectra, thermogravimetric analysis, cyclic voltammetry and X-ray crystallography. The iron(II) complex 1 crystallizes in the monoclinic, space group C2/c, a = 26.664(5) , b = 6.9943(11) , c = 14.727(2) , β = 97.498(3), and Z = 8. The structural study reveals that it is a penta-coordinate Fe(II) dimeric complex.

IPC Code: Int Cl.8 C07F15/02

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1951-1954

 

Preparation and characterization of thelanthanide complex Eu(TTA)3phen / vinylpyrrolidone luminescent nanofiberby electrospinning

Liu Wei * & Wang Ce

Received 15 January 2007; revised 12 October 2007

Eu(TTA)3phen/vinyl pyrrolidone (PVP) composite nanofibers have been prepared by electrospinning technique. The spectral properties of Eu(TTA)3phen/PVP composite nanofibers have been studied, as compared to that of Eu(TTA)3phen powders. The excitation of Eu(TTA)3phen/PVP systems by UV light results in a ligand-to-metal energy transfer and the emission spectra display characteristic luminescence of the central ions (5D07F2 for Eu3+). Photoluminescence measurements show that Eu(TTA)3phen/PVP nanofibers have higher intensity and longer lifetime than that of Eu(TTA)3phen powders because of the influence of PVP on the coordinative environment of lanthanide ions.

IPC Code: Int. Cl.8 B82B; C07F5/00

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1955-1958

 

Preparation of silica nanoparticle through coating with octyldecyltrimethoxy silane

N Venkatathri

Received 13 March 2007; revised 29 October 2007

Silica nanoparticles have been prepared using tetrethylorthosilicate, water, aqueous ammonia, ethanol and octadecyltrimethoxy silane as constituents. Kinetics studies have been carried out to characterize the material by analyzing the yield, which follows an S type curve. At the eighth hour, the yield reaches maximum in time (hours) versus yield (%) plot. In conventional synthesis, a part of the product particles is small in size (100 nm, 80%) while the remaining is bigger in size (300 nm, 20%). The particle size is normalized on addition of octadecyltrimethoxy silane and is increased to a small extent(400 nm). The sample has been analyzed by XRD, SEM, TEM,E-DAX, FT-IR, N2 adsorption and 28Si MASNMR techniques. The sample is amorphous with surface area of 93.54 m2/g and contains Q2, Q3 and Q4 species. TEM reveals the particles to be core shell type which is absent in ODTS-free samples. The samples show Si-O-Si tetrahedral skeletal vibrations.

IPC Code: Int. Cl.8 B82B3/00

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1959-1962

 

Synthesis and crystal structure of the zinc(II) complex of 5-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-ylhydrazono) hexahydropyrimidine -2-thioxo-4,5,6-trione

V Sadasivan & M Alaudeen*

Received 6 March 2007; revised 24 October 2007

Arylazo barbituric acid prepared by coupling diazotized 4-aminoantipyrine with 2-thiobarbituric acid is tautomerised to its hydrazone form, 5-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-ylhydrazono)hexahydropyrimidine-2-thioxo-4, 5, 6-trione [HTB-AAP] and acts as a tridentate monovalent ligand towards zinc(II) as evidenced by IR, 1H-NMR and electronic spectra. The single crystal X-ray study of [Zn(TBAAP)(H2O)2]NO3.DMSO reveals that the coordinating sites are the azomethine nitrogen and the two carbonyl oxygen atoms on the pyrazolone and the thiobarbituric acid rings. The zinc(II) ion is five coordinated and nitrate is in the ionic state. Thermal studies support the presence of two coordinated water molecules. XRD investigations confirm the presence of one molecule DMSO as solvate in the complex.

IPC Code: Int. Cl.8 C07F5/00

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1963-1968

 

Complexes of ruthenium(III), rhodium(III) and iridium(III) with ligands bearing 2,6-diacetylpyridine bis(S-alkylisothiosemi-carbazones): Synthesis, spectral studies and structural elucidation

Vinod K Sharma* & Ankita Srivastava

Received 27 November 2006; revised 5 November 2007

Reactions of the ligands, 2,6-diacetylpyridine bis(S-methylisothiosemicarbazone) and 2,6-diacetylpyridine bis(S-butylisothiosemicarbazone) with ruthenium(III), rhodium(III) and iridium(III) have been studied and their structures have been proposed based on elemental analyses, molar conductance, magnetic moment, spectral data (IR, 1H NMR, FAB mass) and thermal investigations. The ligands behave as pentacoordinated and give acyclic complexes of the general formula [M(H2L)Cl2]Cl and macrocyclic complexes, [M(L)Cl2]ClH2O, which are formed by template condensation by using β-diketones. Pentagonal bipyramidal geometries are observed for acyclic and macrocyclic complexes. In both types of complexes, the ligands coordinate in their amino form. The thermal stability and mode of decomposition of the various complexes have been studied by TGA techniques. Conductance measurements reveal 1:1 electrolytic nature of the complexes.

IPC Code: Int. Cl.8 CO7F15/00

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1969-1971

 

Kinetics and mechanism of visible light induced oxidation of hydrazine by peroxodisulphate in aqueous solution containing tris-(2,2-bipyridine) ruthenium(II)

Savita Bansal, N K Soni, C L Khandelwal & P D Sharma*

Received 8 December 2006; revised 1 October 2007

The rate of visible light induced oxidation of hydrazine by peroxodisulphate in the presence of tris-(2,2-bipyridine)-ruthenium(II) [Ru(bipy)32+] in aqueous solution is independent of the substrate concentration but increases with the intensity of light absorbed as follows:

where ki is the initial rate and other the terms have their usual meaning.

IPC Code: Int. Cl.8 C07B33/00

 

Indian Journal of Chemistry

Vol. 46A, December 2007, pp. 1972-1978

 

Excess transport properties of binary mixtures of methanol and pyridine through ultrasonic measurements at different temperatures

G V Rama Rao, A Viswanatha Sarma, D Ramachandran & C Rambabu*

Received 1 August 2006; revised 3 October 2007

The viscosities, densities and ultrasonic velocities of binary liquid mixtures of methanol with piperidine and morpholine and pyridine with piperidine and morpholine have been determined at 303.15 to 318.15K over the entire composition range. These data have been utilized to estimate the excess free volume, excess internal pressure, excess enthalpy, excess velocity, excess acoustic impedance and excess Gibbs free energy of activation of flow. The results obtained have been discussed in the light of existing theories of molecular interaction involved and chemical constitution of the liquid components. Analysis of these parameters indicates that there are intermolecular interactions among components of the binary mixtures that lead to possible hydrogen bond formation (of the type NH-O) between unlike molecules.