Indian Journal of Chemistry

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

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VOLUME 48A

NUMBER 5

May 2009

CONTENTS

 

623

 

Theoretical binding affinities and spectroscopy of complexes formed by cyclobis(paraquat-p-anthracene) with amino acids

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

X Ren, Y Miao, N Li & S Wu*

 

 

 

 

Electronic structures and spectroscopy of the complexes formed by cyclobis(paraquat-p-anthracene) with amino acids have been studied using the semi-empirical AM1 method and density function theory. The energy gaps of the complexes decrease due to the formation of hydrogen bonds. The stretching vibration frequencies of the C-H bonds in the IR spectra of the complexes calculated with AM1 method are red shifted as compared with those of the host. The chemical shifts of the carbon atoms adjacent to the hydrogen bonds, calculated at B3LYP/3-21G level, generally move downfield, whereas those of the carbon atoms next to the nitrogen atoms move upfield.

 

 

 

 

 

631

 

Tailoring electrically conducting copolymers using genetic algorithm

 

 

 

 

 

 

 

 

 

 

 

Avneet Kaur & A K Bakhshi*

 

 

 

 

There are different stages in the production of polymers, starting from the design of molecules, through their manufacture in reactors, and finally ending with their processing. Application of genetic algorithm in obtaining the optimal solution for a copolymer with minimum band-gap and maximum delocalization is discussed. Quasi-one-dimensional model binary polymeric superlattices belonging to Type I and Type II- staggered have been investigated using genetic algorithm.

 

 

637

 

Copper(II) catalysed oxidation of alcohols in aqueous medium

 

 

 

 

 

 

 

 

 

 

 

Purabi Sarmah, Rama K Barman,
Pratyush Purkayastha, Sanchay J Bora,
Prodeep Phukan & Birinchi K Das*

 

 

 

 

A water soluble Cu(II) chain polymer, [Cu(4-CNpy)2Cl2]n, has been prepared in excellent yield and utilized as catalyst precursor for the oxidation of alcohols in aqueous medium with TBHP(aq.) as the oxidant under atmospheric pressure.

 

 

 

645

 

Kinetics and mechanism of uncatalyzed oxidation of hydrazine with superoxide coordinated to cobalt(III)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Amit Mondal & Rupendranath Banerjee*

 

 

 

 

In the absence of any catalyzing metal ion, the bridging superoxo ligand in [(NH3)10Co2III(m-O2)]5+ ion oxidizes hydrazine to N2 through a [H+]-1 dependent path, which arises due to formation of conjugate base by the Co2III complex.

 

 

 

 

 

650

 

Refractrometric studies on molecular interactions between some bromoalkanes and nonpolar hydrocarbons

 

 

 

 

 

 

 

 

 

 

 

S S Yadava *, Aniruddh Yadav, Neetu Kushwaha & Neetu Yadav

 

 

 

 

Refractive indices of twelve binary mixtures between polar aliphatic molecules, viz., 1-bromopropane, 1-bromobutane,
1-bromopentane and nonpolar hydrocarbon molecules, viz., cyclohexane, benzene, 1,4-dimethylbenzene and 1,3,5- trimethyl-benzene for the entire concentration range have been measured at 308.15 K. Molar refraction and molecular radius and deviations from the values for ideal mixtures for these mixtures have also been evaluated.

 

Notes

 

 

658

 

Extending the phenyl-cyclopentadienyl rule

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ivan Gutman*, Svetlana Jeremic &
Vladimir Petrovic

 

 

 

 

According to the PCP rule, a six-membered ring which is connected to a five-membered ring by a single carbon-carbon bond increases the cyclic conjugation in the five-membered ring. An analogous regularity also exists in polycyclic conjugated species possessing an odd-membered ring of size greater than five.

 

 

 

663

 

Syntheses, crystal structures and antibacterial activities of two zinc complexes derived from
4-bromo-2-[(2-methylaminoethylimino)methyl]phenol

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rui-Hua Hui *, Peng Zhou & Zhong-Lu You

 

 

 

 

Reactions of the tridentate Schiff base
4-bromo-2-[(2-methylaminoethylimino)methyl]phenol with zinc acetate and zinc chloride, afford two polynuclear zinc complexes, [Zn{ZnL2-acetato-O,O)(μ2-acetato-O,O)}2] and [Zn2L2Cl2] respectively.

 

 

 

 

668

 

Extraction chromatographic method of preconcentration and separation of cadmium(II) with high molecular mass liquid cation exchanger, Versatic 10

 

 

 

 

 

 

B Mandal*& N Ghosh

 

 

 

 

A selective method has been developed for the extraction chromatographic separation of Cd(II) with Versatic 10 coated on silanised silica gel. Quantitative extraction has been achieved from 0.1M acetate buffer at the optimum pH of 6.0-7.5. The method is found effective for removal and recovery of Cd(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of Cd(II) has been suggested.

 

 

672

 

Determination of dynamic dissociation constant of chromium-poly(N-vinylpyrrolidone) complex by the radiotracer technique

 

 

 

 

 

 

 

Dalia Nayak, Anupam Banerjee, Kingshuk Ghosh, Ayan Das & Susanta Lahiri*

 

 

 

The binding ability of polyvinylpyrrolidone with chromium in its different oxidation states has been investigated. Both Cr(VI)-PVP and Cr(III)-PVP complexes are most stable at pH 7. However, the Cr(III)-PVP complex is more stable than the Cr(VI)-PVP complex at all pH values.

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 623-630

 

 

Theoretical binding affinities and spectroscopy of complexes formed by cyclobis(paraquat-p-anthracene) with amino acids

X Rena, b, Y Miaoa, N Lic & S Wua, *

aDepartment of Chemistry, bDepartment of Pharmacy, Zhejiang University, Hangzhou 310027, PR China

Email: wushi@zju.edu.cn

cDepartment of Chemical Engineering, Liaoning Geology Engineering Vocational College, Dandong 118008, PR China

Received 18 February 2009; accepted 31 March 2009

The electronic structures and spectroscopy of the complexes formed by cyclobis(paraquat-p-anthracene) with amino acids have been studied using the semi-empirical AM1 method and density function theory. Based on the B3LYP/3-21G optimized geometries, the energies of the complexes have been calculated at B3LYP/6-31G(d) level. The binding energies of the complexes have been obtained after the correction of basis set superposition error. The energy gaps of the complexes are decreased due to the formation of hydrogen bonds. The stretching vibration frequencies of the C-H bonds in the IR spectra of the complexes calculated with AM1 method are red shifted as compared with those of the host. The chemical shifts of the carbon atoms adjacent to the hydrogen bonds, calculated at B3LYP/3-21G level, generally move downfield, whereas those of the carbon atoms next to the nitrogen atoms move upfield. Most of the complexes are less aromatic than the host, based on the nuclear independent chemical shifts calculated at B3LYP/3-21G level.

Keywords: Theoretical chemistry, Spectroscopy, Binding affinities, Density function theory, Aromaticity, Cyclobis(paraquat-p-anthracene), Amino acids

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 631-636

 

 

Tailoring electrically conducting copolymers using genetic algorithm

Avneet Kaur & A K Bakhshi*

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

Email: akbakhshi2000@yahoo.com

Received 16 February 2009; revised and accepted 13 April 2009

In the last several years, genetic algorithm has gained wide acceptance as a robust optimization algorithm in almost all areas of science and engineering, including polymer science. There are different stages in the production of polymers, starting from the design of molecules, through their manufacture in reactors, and finally ending with their processing. In each stage, genetic algorithm can be and has been used to determine optimum solutions. The application of genetic algorithm in obtaining the optimal solution for a copolymer with minimum band-gap and maximum delocalization is discussed. Quasi-one-dimensional model binary polymeric superlattices belonging to Type I and Type II-staggered have been investigated using genetic algorithm.

Keywords: Theoretical chemistry, Genetic algorithm, Polymers, Conducting polymers, Copolymers

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 637-644

 

 

Copper(II) catalysed oxidation of alcohols in aqueous medium

Purabi Sarmah, Rama K Barman, Pratyush Purkayastha, Sanchay J Bora, Phukan & Birinchi K Das*

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

Email: Birinchi.Das@hotmail.com

Received 10 February 2009; accepted 8 April 2009

 

An environmentallly friendly, homogeneous catalytic method for the oxidation of alcohols in aqueous medium is described. The copper(II) complex, [Cu(4-CNpy)2Cl2]n, has been prepared in excellent yield and characterized by the single crystal X-ray diffraction technique. It crystallizes in the monoclinic space group P21/n with unit cell parameters a = 3.589(3), b = 25.903(6) , c = 7.116(1), b = 96.05(4), V = 657.9(6) 3, and Z = 2. The crystal structure refinement yields final R1 = 0.0604, wR2 = 0.1577 and GooF = 1.055 for all 1423 unique reflections and 105 L.S. parameters. The results of crystal structure analysis show that the copper(II) compound is a one dimensional coordination polymer containing chloride ions as the bridging ligands forming one weak [Cu-Cl = 2.870(2) ] and one strong [Cu-Cl = 2.333(1) ] coordination bond with copper(II) centres. The Cu(II) complex (2 mol%) shows very good catalytic activity towards oxidation of alcohols under homogeneous condition using aqueous TBHP as the oxidant in H2O:MeCN (5:1 v/v). Products have been isolated in moderate to high yields either as aldehydes or ketones using the above green protocol.

Keywords: Coordination polymers, Homogeneous catalysis; Catalysis, Oxidations, TBHP oxidations;

Alcohol oxidations, Copper, Aqueous solvents

IPC Code: Int. Cl.8 C07B33/00; C07F1/08

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 645-649

 

 

Kinetics and mechanism of uncatalyzed oxidation of hydrazine with

superoxide coordinated to cobalt(III)

Amit Mondal & Rupendranath Banerjee*

Department of Chemistry, Jadavpur University, Kolkata 700 032, India

Email : rupenju@yahoo.com

Received 10 December 2008; revised and accepted 1 April 2009

Hydrazine, in deoxygenated aqueous solutions at moderate pH 3.8-6.1, quantitatively reduces [(NH3)5CoIII(m-superoxo)CoIII(NH3)5]5+ (I) to the corresponding peroxo complex, [(NH3)5CoIII(m-peroxo)CoIII(NH3)5]4+ (II) which, instead of reacting with another molecule of hydrazine quickly decomposes to Co2+ according to the overall stoichiometry: 4(I) + N2H5+ + 35H+ = 8Co2+ + 40NH4+ + N2 + 4O2. The reaction is dramatically catalyzed by Cu2+, to the degree that impurity levels of Cu2+ are sufficient to mask the direct reaction such that the direct oxidation process is inaccessible, though the reaction is not catalyzed by any of the other usual transition metal centers. Dipicolinic acid is a very effective inhibitor of this trace metal ion catalysis, and with 0.10 mM dipicolinic acid, the direct oxidation can be studied, which reveals an inverse [H+] dependence of reaction rate for the direct reaction. This has been ascribed to the formation of a conjugate base, [(NH3)4(NH2)CoIII(m-superoxo)CoIII(NH3)5]4+ as the kinetically active species. Change in buffer concentration has no effect on the rate, neither is there any observable kinetic solvent isotope effect. Enthalpy of activation has a moderate value while the entropy of activation is moderately negative. A reaction scheme consistent with these kinetic and stoichiometric observations has been proposed.

Keywords: Kinetics, Oxidations, Superoxides, Hydrazines, Cobalt

IPC Code: Int. Cl.8 CO7B33/00

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 650-657

 

 

Refractrometric studies on molecular interactions between some bromoalkanes and nonpolar hydrocarbons

S S Yadava*, Aniruddh Yadav, Neetu Kushwaha & Neetu Yadav

Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273 009, India

Email: ssyadava1@rediffmail.com

Received 13 March 2009; accepted 8 April 2009

Refractive indices of the twelve binary mixtures between polar aliphatic molecules, viz., 1-bromopropane, 1-bromobutane, 1-bromopentane and nonpolar hydrocarbon molecules, viz., cyclohexane, benzene, 1, 4-dimethylbenzene and 1, 3, 5- trimethylbenzene for the entire concentration range have been measured at 308.15 K. Deviation in refractive indices from that for ideal mixture, molar refraction, deviation in molar refraction from ideal mixture values, molecular radius and deviation in molecular radius from the values for ideal mixtures for these mixtures have also been evaluated. The results are discussed in terms of molecular interactions between the components of the binary mixtures.

Keywords: Refractive indices, Molecular interactions, Bromoalkanes, Hydrocarbons

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp.658-662

 

 

Extending the phenyl-cyclopentadienyl rule

Ivan Gutman*, Svetlana Jeremić & Vladimir Petrović

Faculty of Science, P.O. Box 60, 34000 Kragujevac, Serbia

Email: gutman@kg.ac.rs

Received 26 February 2009; accepted 8 April 2009

By examining the energy effect of cyclic conjugation in individual rings of acenaphthylene- and fluoranthene-type polycyclic conjugated molecules, a peculiar regularity - named the PCP rule - was recently discovered [Gutman, I, Đurđević J & Balaban A T, Polycycl Arom Comp, 29 (2009) 3]. According to the PCP rule, a six-membered ring which is connected to the five-membered ring by a single carbon-carbon bond increases the cyclic conjugation in the five-membered ring. An analogous regularity also exists in polycyclic conjugated species possessing an odd-membered ring of size greater than five.

Keywords:Theoretical chemistry, Graph theory, PCP rule, Energy effects, Cyclic conjugation, Polycyclic conjugation

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 663-667

 

 

Syntheses, crystal structures and antibacterial activities of two zinc complexes derived from 4-bromo-2-[(2-methylaminoethylimino)- methyl]phenol

Rui-Hua Hui a, *, Peng Zhoub & Zhong-Lu Youb

aDepartment of Chemistry, Anshan Normal University, Anshan 114007, PR China

Email: ruihua_hui@126.com

bDepartment of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, PR China

Received 9 February 2009; revised and accepted 6 April 2009

Reactions of the tridentate Schiff base, 4-bromo-2-[(2-methylaminoethylimino)methyl]phenol with zinc acetate and zinc chloride, afford two polynuclear zinc complexes, [Zn{ZnL2-acetato-O,O)(μ2-acetato-O,O)}2] (1), and [Zn2L2Cl2] (2) respectively Complex (1) is a centrosymmetric trinuclear zinc compound, in which the two terminal Zn atoms are five-coordinate in a distorted square-pyramidal geometry, while the central Zn atom is six-coordinate in an octahedral geometry. Complex (2) is a dinuclear zinc compound, which possesses a two-fold rotation axis. In (2), one Zn atom is four-coordinate in a tetrahedral geometry, and the other one is six-coordinate in an octahedral geometry. The antibacterial activities of the Schiff base and the two complexes have also been tested

Keywords: Coordination chemistry, Schiff bases, Polynuclear complexes, X-ray crystallography, Zinc

IPC Code: Int. Cl.8: C07C251/02, CO7F3/06

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 668-671

 

 

Extraction chromatographic method of preconcentration and separation of cadmium(II) with high molecular mass liquid cation exchanger, Versatic 10

B Mandal* & N Ghosh

Department of Chemistry, Visva-Bharati, Santiniketan 731 235, India

Email: bhabatosh_mandal@yahoo.co.in

Received 15 July 2008; revised and accepted 31 March 2009

A selective method has been developed for the extraction chromatographic separation of Cd(II) with Versatic 10 coated on silanised silica gel. The quantitative extraction has been achieved from 0.1M acetate buffer at the optimum pH of 6.0-7.5. The effects of pH, flow-rate and stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to Cd(II) has been determined. Cd(II) has been separated from synthetic binary and multi-component mixtures containing various metal ions associated with it in ores and alloy samples. The method effectively permits sequential separation of Cd(II) from synthetic quaternary mixture containing its congeners, Cu(II), Sn(II), Hg(II), Cu(II), Sn(II) and Bi(III), of the same analytical group. The method is found effective for removal and recovery of Cd(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of Cd(II) has been suggested.

Keywords: Analytical chemistry, Chromatography, Ion exchanger, Cation exchanger, Liquid cation exchanger, Cadmium, Versatic 10, Extraction chromatography

IPC Code: Int. Cl.8 B01D15/04; B01D15/08; B01J39/00; G01N30/02

 

 

Indian Journal of Chemistry

Vol. 48A, May 2009, pp. 672-675

 

 

Determination of dynamic dissociation constant of chromium-
poly(N-vinylpyrrolidone) complex by the radiotracer technique

Dalia Nayaka, Anupam Banerjeea, Kingshuk Ghoshb,
Ayan Dasb & Susanta Lahiria, *

aChemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India

Email: susanta.lahiri@saha.ac.in

bDepartment of Chemistry, University of Kalyani, Kalyani, Nadia 741 235, India

Received 23 December 2008; revised and accepted 20 April 2009

The binding ability of polyvinylpyrrolidone (PVP) with chromium in its different oxidation states has been investigated. The complexation of PVP towards Cr(III) and Cr(VI) labeled with 51Cr radionuclide has been studied with the dialysis technique. The stability of the complexes has been examined by measuring the dynamic dissociation constant from the slope of the plot of ln{Cr(VI)/(III)-PVP} versus time. It has been observed that both Cr(VI)-PVP and Cr(III)-PVP complexes are most stable at pH 7. However, the Cr(III)-PVP complex is more stable than the Cr(VI)-PVP complex at all pH values. This study shows the comparative stability of the complexes of the two different species of chromium with PVP, which may be useful in radiopharmaceutical sciences.

 

Keywords: Solution chemistry, Dissociation constants, Binding ability, Stability, Radiotracer technique, Chromium