Indian Journal of Chemistry

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

CODEN: ICACEC; ISSN: 0376-4710 (Print), 0975-0975 (Online)

 

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VOLUME 50A

NUMBER 6

JUNE 2011

CONTENTS

 

763

 

Supramolecular aggregation in alkaline earth
metal 3- and 4-hydroxybenzoates using
1,10-phenanthroline auxiliary

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Remya Korah, Laksheswar Kalita &
Ramaswamy Murugavel
*

 

 

 

Incorporation of N-donor ligands in the coordination sphere of alkaline earth metal ion hydroxybenzoate complex has been achieved. The N-donor ligands often occupy the same side of the large coordination sphere of these metal ions.

 

 

 

775

 

Synthesis, spectral and structural characterization of Cu(II) complexes of a tridentate NNO donor Schiff base carrying a pendant benzimidazolyl arm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Robin Kumar, Kuldeep Mahiya & Pavan Mathur*

 

 

 

Copper(II) in the complex [Cu(L)CH3COO] adopts a distorted square planar geometry and selectively oxidises dopamine to dopachrome  in the presence of molecular oxygen as an oxidant.

 

 

 

 

781

 

Thermoresponsive polystyrene-b-poly(N-isopropyl-acrylamide) copolymers by atom transfer radical polymerization

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vaishali S Shinde*, Madhavi R Girme &
Vishwas U Pawar

 

 

 

A well defined amphiphilic block copolymer based on styrene and N-isopropylacrylamide using ATRP technique has
been synthesized in a two-step process. This temperature-responsive block with a hydrophobic block is attractive for biomedical applications.

 

 

 

 

 

 

Notes

 

788

 

Eutectic mixture-directed kinetics of Diels-Alder reaction

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Amit S Nagare & Anil Kumar*

 

 

 

Eutectic mixtures of carbohydrates with urea and dimethyl urea are effective solvent media for bimolecular Diels-Alder reactions.

 

 

 

 

 

793

 

FT-IR and FT-Raman spectral studies and DFT calculations of tautomeric forms of benzaldehyde-N(4)-phenylsemicarbazone

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V L Siji, M R Sudarsanakumar*, S Suma,
Abraham George & P V Thomas

 

 

 

The vibrational wave numbers of the keto and enol forms of benzaldehyde-N(4)-phenylsemicarbazone have been computed using B3LYP/6-311++G** level of theory and compared with experimental FT-IR and FT-Raman data. Optimized geometrical parameters of the title compound are in agreement with the reported structures. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives. The extended π-electron delocalization over the semicarbazone moiety is responsible for the nonlinearity of
the molecule.

 

 

 

798

 

Growth of nanosized cupric sulphate–urea complex in aqueous medium and its characterization

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ishwar Das*, Shoeb A Ansari & N R Agrawal

 

 

 

Cupric sulphate-urea complex with particle diameter in the range 24-120 nm, has been synthesized and characterized.

 

 

 

 

802

 

Synthesis of crosslinked poly(vinyl alcohol) and studies on its efficiency in zinc ion uptake from aqueous solution

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P Chowdhury*, A Mukherjee & B Singha

 

 

 

 

 

 

 

 

807

 

Guide to Authors

 

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 763-774

 

Supramolecular aggregation in alkaline earth metal
 3- and 4-hydroxybenzoates using 1,10-phenanthroline auxiliary

Remya Korah, Laksheswar Kalita & Ramaswamy Murugavel*

Department of Chemistry, Indian Institute of Technology-Bombay, Mumbai 400 076, India

Email: rmv@chem.iitb.ac.in

Received 28 April 2011; accepted 17 May 2011

The interaction of group 2 metals with 3- and 4-hydroxybenzoic acids in presence of chelating
N-donor ligand 1,10-phenanthroline (phen) has been investigated. The 3-hydroxybenzoate derivatives
[Ca(3-hba)2(phen)2(H2O)3]n (1), [Sr(3-hba)2(phen)2(H2O)2]n (2), and [Ba(3-hba)2(phen)2(H2O)2]n (3) have been obtained by treatment of the corresponding metal carbonates with 3-hydroxybenzoic acid and
1,10-phenanthroline, while the 4-hydroxybenzoate derivatives
[Ca(4-hba)2(phen)2(H2O)] (4),
[Sr(4-hba)2(phen)2(H2O)4] (
5), [Ba(4-hba)2(phen)2(H2O)2] (6) have been prepared by a similar method using 4-hydroxybenzoic acid. The compounds have been characterized by elemental analysis, thermal analysis, and infrared and 1H NMR spectroscopic studies. The solid-state structures of (2-4) and (6) have been established by single-crystal X-ray diffraction studies. The compounds are monomeric in the solid state although they exhibit considerable variations in their molecular structures in terms of binding mode of the hba ligands and the coordination geometry around the metal ions. All the compounds form polymeric networks in the solid state with the aid of O-H×××O, C-H×××O and N-H×××O hydrogen bonding and p-p interactions.

Keywords:   Coordination chemistry, Aggregation, Supramolecular aggregation, Benzoates, Auxiliary ligands, Crystal structures

Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 775-780

 

Synthesis, spectral and structural characterization of Cu(II) complexes of a tridentate NNO donor Schiff base carrying a pendant benzimidazolyl arm

Robin Kumar, Kuldeep Mahiya & Pavan Mathur*

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

Email: pavanmat@yahoo.co.in

Received 29 November 2010; revised and accepted 16 May 2011

Three new Cu(II) complexes of a Schiff base ligand, 2-[2-(1H-benzo[d]imidazol-2-yl)ethylimino)methyl]phenol, (HL), derived from 2-aminoethylbenzimidazolyl and salicylaldehyde have been synthesized and characterized by elemental analysis and electronic and IR spectroscopy. Results show that HL acts as tridentate ligand and coordinates through the imine nitrogen of benzimidazole ring, the azomethine nitrogen and a deprotonated phenolic oxygen of the Schiff base. One of the complex with the composition [Cu(L)CH3COO] has been structurally characterized. X-ray diffraction data reveals that the compound crystallizes in monoclinic space group P21/c with cell parameters of a = 12.8602(8) Å,
b = 18.1466(10) Å, c = 8.1250(4) Å, α = 90º, β = 103.757(6) º, γ = 90º and Z = 4. The copper(II) ion adopts a distorted square planar geometry involving the N, N and O atoms of L and an O atom of acetate anion. The four bond distances are nearly equal. Kinetics of oxidation of dopamine using molecular oxygen as an oxidant and [Cu(L)CH3COO] as catalyst has also been studied spectrophotometrically. The complex catalyses the oxidation of dopamine to dopachrome or aminochrome in methanol.

Keywords: Coordination chemistry, Copper, Benzimidazoles, Schiff bases, Dopamine, Oxidase activity



Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 781-787

 

Thermoresponsive polystyrene-b-poly(N-isopropylacrylamide) copolymers by atom transfer radical polymerization

Vaishali S Shinde*, Madhavi R Girme & Vishwas U Pawar

Department of Chemistry, Garware Research Centre, University of Pune, Pune 411 007, Maharashtra, India

Email: vsshinde@chem.unipune.ac.in

Received 20 January 2011; revised and accepted 26 May 2011

Atom transfer radical polymerization has been employed for the polymerization of styrene initiated by ethyl-2-bromoisobutyrate in anisole at 100 °C with Cu(I)Br/PMDETA as the catalytic system. Kinetic investigations reveal that polymerization of styrene proceeds in a controlled manner with a first order plot of monomer consumption and with low polydispersity (Mw/Mn < 1.10). Well defined thermoresponsive diblock copolymer has been successfully synthesized using PS-Br macroinitiator. The amphilphilic behaviour of the diblock copolymers leads to phase separation resulting in two glass transition temperatures as detected by DSC. TGA analysis also shows the two-step decomposition.

Keywords: Polymerization, Atom transfer radical polymerization, Copolymers, Block copolymers, Thermoresponsive polymers, Poly(N-isopropylacrylamide), Polystyrene

 

 

Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 788-792

 

Eutectic mixture-directed kinetics of Diels-Alder reaction

Amit S Nagare & Anil Kumar*

Physical Chemistry Division, National Chemical Laboratory, Pune 411 008, India

Email: a.kumar@ncl.res.in

Received 29 April 2011; revised and accepted 18 May 2011

In the search for environmentally benign solvent media, a new class of solvents composed of mixtures of carbohydrates with urea or methylated urea has been noted to be effective in enhancing the reaction rates of a bimolecular organic reaction like the Diels-Alder reaction of cyclopentadiene with methyl acrylate. The viscosity of these media appears to be an important parameter in controlling the second order kinetics.

Keywords: Cycloaddition, Diels-Alder reaction, Solvent effects, Kinetics, Reaction rates, Viscosity, Carbohydrates, Urea, Dimethylurea

 

 

 

 

Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 793-797

 

FT-IR and FT-Raman spectral studies and DFT calculations of tautomeric forms of benzaldehyde-N(4)-phenylsemicarbazone

V L Sijia, M R Sudarsanakumara, *, S Sumab, Abraham Georgec & P V Thomasd

 aDepartment of Chemistry, Mahatma Gandhi College, Thiruvananthapuram, Kerala 695 004, India

Email: sudarsanmr@gmail.com

 bDepartment of Chemistry, SN College, Chempazhanthy, Thiruvananthapuram, Kerala, 695 587, India

cDepartment of Chemistry, Mar Ivanios College, Thiruvananthapuram, Kerala 695 015, India

 dDepartment of Physics, Mar Ivanios College, Thiruvananthapuram, Kerala 695 015, India

Received 6 September 2010; re-revised and accepted 26 May 2011

The vibrational wave numbers of the keto and enol forms of benzaldehyde-N(4)-phenylsemicarbazone have been computed using B3LYP/6-311++G** level of theory and compared with experimental FT-IR and FT-Raman data. Optimized geometrical parameters of the title compound are in agreement with the reported structures. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies on non-linear optics. The extended π-electron delocalization over the semicarbazone moiety is responsible for the nonlinearity of the molecule.

Keywords: Theoretical chemistry, Vibrational spectroscopy, Raman spectroscopy, Density functional calculations, Hyperpolarizability, Semicarbazones

 

Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 798-801

 

Growth of nanosized cupric sulphate–urea complex in aqueous medium
 and its characterization

Ishwar Dasa, *, Shoeb A Ansarib & N R Agrawalb

aChemistry Department, DDU Gorakhpur University, Gorakhpur 273 009, India

Email: ishwar_das@rediffmail.comb

Chemistry Department, St. Andrew’s College, Gorakhpur 273 001, India

Received 28 March 2011; revised and accepted 23 May 2011

Cupric sulphate-urea complex has been prepared in aqueous medium and growth morphologies of complex and reactants have been compared. Morphology of the complex is different as compared to those of the individual reactants. UV-vis spectra of pure cupric sulphate and aqueous solutions of complex prepared in different cupric sulphate and urea ratio show the maximum shift in λmax when the molar ratio of cupric sulphate and urea is 1:2. Detailed investigation of the 1:2 complex has been carried out by IR, powder X-ray diffraction, thermogravimetry, differential thermal analysis and electron spin resonance studies. Surface topology of the complex has been studied by atomic force microscopy and the particle diameter observed by transmission electron microscopy. Nanosized complex is formed with particle diameter in the range 24-120 nm, while the average thickness of the particle is in the range of 634 -1260 nm.

Keywords: Crystal growth, Growth morphology, Nanomaterials, Cupric sulphate, Urea

 

 

 

 

 

 

Indian Journal of Chemistry

Vol. 50A, June 2011, pp. 802-806

 

Synthesis of crosslinked poly(vinyl alcohol) and studies on its efficiency in zinc ion uptake from aqueous solution

P Chowdhury*, A Mukherjee & B Singha

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

Email: pranesh_02@yahoo.co.in

Received 3 September 2010; revised and accepted 16 May 2011

Crosslinking of polyvinyl alcohol by methylene bis acrylamide has been carried out for binding Zn(II) cations from aqueous solution. Metal ion uptake capacity of the crosslinked polymer has been evaluated in the light of varying pH, temperature, time and concentration by batch equilibrium procedure. The polymer has been characterized by chemical, TGA and FTIR data. Surface morphology has been studied with the help of SEM images. Zn(II) has been isolated quantitatively from various synthetic mixtures containing metal ions (Ni(II), Cd(II) and Cu(II)) commonly found in the effluent of galvanization industry. The method has also been tested by analyzing real alloy samples.

Keywords: Analytical Chemistry, Crosslinked polymers, Solid phase extraction, Zinc