Indian Journal of Chemistry

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

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

 

 

 

 

 

VOLUME 54A

NUMBER 1

JANUARY 2015

 

CONTENTS

 

 

9

 

Designing of novel donor-acceptor-donor framework based low band gap copolymers using an artificial intelligence approach

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Priyanka Thakral & A K Bakhshi*

 

 

 

Novel binary D-A-D copolymers have been designed using the PSO algorithm. The donor moieties considered are thiophene, pyrrole and furan with >C-(CN)2 and >C=O acceptor groups. A higher relative percentage of PPYCO in a copolymer is highly desirable for designing low Eg materials. PPYCO-PFUCN copolymer is found to have the lowest band gap.

 

 

 

 

 

 

 

20

 

Synthesis of Y2Ti2O7-xNy with visible light responsive photocatalytic activity

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G Ravi, Saleh Mansouri, Suresh Palla & M Vithal*

 

 

 

Nitrogen doped Y2Ti2O7 is prepared by a facile solid state method using urea as a source of nitrogen. It is a visible light responsive photocatalyst and degrades organic pollutants such as methylene blue, rhodamine B and 4-chlorophenol under visible light irradiation.

 

 

 

 

 

 

 

27

 

Ultrafast radiationless decay mechanisms through conical intersections in cytosine: Computational insight and topological analysis of the charge density distributions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rifaat Hilal*, Saadullah G Aziz, Abdulrahman O Alyoubi & Shaaban A Elroby

 

 

 

Contour plots and relief maps have been analyzed for regions of valence shell charge concentrations and depletions in the ground state and the two CI structures of cytosine. NBO analysis reveals that the conformational and overall stability of the studied cytosine conformations are facilitated by the competitive conjugative and the lone-pair interactions.

 

 

 

Notes

 

35

 

A two-component co-crystal of Cu(II) complex of
p-tolyl-terpyridine

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dibyendu Bhattacharya

 

 

 

The two-component co-crystal, [Cu(L)(NO3)2][Cu(L)(NO3)-(CH3OH)](NO3)∙H2O (L = p-tolyl-terpyridine) crystallizes in the triclinic system (space group P) and comprises two mononuclear Cu(II) moieties, one cationic and the other neutral. While one of the Cu(II) centres furnishes a five-coordinated distorted square pyramidal geometry (CuN3O2), the other Cu(II) centre displays a four-coordinate distorted square planar geometry (CuN3O).

 

 

 

 

 

40

 

Kinetic and physicochemical analysis of structurally different bis-pyridinium oximes against pesticide inhibited AChE

 

 

 

 

 

 

 

 

 

 

 

 

Arvind Kumar Sahu, Bhanushree Gupta,
Rahul Sharma, Yama Singh, Kamil Musilek,

Kamil Kuca & Kallol K Ghosh
*

 

 

 

The effect of functional group on the second pyridinium ring of
bis-pyridinium oximes for the reactivation of paraoxon inhibited AChE is studied. Reactivation studies show that K250 is the most efficient reactivator among all the investigated oximes, although it could not surpass the reactivity of standard oximes against paraoxon.

 

 

 

46

 

Synthesis of β-MnO2 nanowires and their electrochemical capacitive behavior

 

 

 

 

 

 

 

 

 

 

 

 

 

Indra B Singh* & Su-Moon Park

 

 

 

Well-defined γ-MnOOH and β-MnO2 nanowires are synthesised using hydrothermal process. The synthesized γ-MnOOH nanowires are transformed to β-MnO2 nanowires (20-30 nm in width and >5 m in length) which show nearly three times higher specific capacitance (404 F/g) as compared to commercial grade MnO2. The present synthesis process indicates that
β-MnO2 can be prepared in large scale.

 

 

 

 

 

52

 

Influence of hydrogen bonding on the conformational stability of calix[4]crown-4 ether

 

 

 

 

 

 

 

 

 

 

 

 

Satish Kumar*, K M Mathew, Neelam, P R Sahoo & Arun Kumar

 

 

 

Influence of non-covalent interactions on the conformational stability of calix[4]crown-4 ether is investigated using various quantum mechanical methods. The relative stability of the conformers follows the order: cone > partial cone > 1,3-alternate.

 

 

59

Guide to Authors

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

 

 

 

 

 

 


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Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 9-19

 

 

Designing of novel donor-acceptor-donor framework based low band
gap copolymers using an artificial intelligence approach

Priyanka Thakrala & A K Bakhshia, b, *

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

bTertiary Education Commission (TEC), Reduit, Mauritius

Email: akbakhshi2000@yahoo.com

Received 12 September 2014; revised and accepted 11 December 2014

Donor-acceptor strategy is employed for designing low band gap hetero-aromatic copolymers using an artificial intelligence mechanism, viz., particle swarm optimization. The investigated structures include hetero-aromatic donor moieties, viz., pyrrole, thiophene and furan in combination with carbonyl and dicyanomethylene acceptor groups. The electronic properties of all the possible donor and acceptor combinations have been compared using the band structure results derived from ab initio Hartree Fock crystal orbital calculations. Of the studied copolymer combinations, the pyrrole-carbonyl donor-acceptor polymeric packaging is found to be most effective due to efficient push-pull effect in the polymer backbone. The pattern of optimized outcomes shows the significant influence of heteroatom on the electronic structures of the copolymers and provides judicious choice of donor and acceptor groups for molecular tailoring of low band gap materials.

Keywords: Theoretical chemistry, Computational chemistry, Copolymerization, Donor-acceptor polymerization, Particle swarm optimization, Conducting polymers, Band gap, Hetero-aromatic polymers

 

Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 20-26

 

 

Synthesis of Y2Ti2O7-xNy with visible light responsive
photocatalytic activity

G Ravi, Saleh Mansouri, Suresh Palla & M Vithal*

Department of Chemistry, University College of Science, Osmania University, Hyderabad 500 007, India

Email: muga_vithal@rediffmail.com

Received 10 June 2014; revised and accepted 22 December 2014

Nanosized pyrochlores, Y2Ti2O7 (YTO) and N-doped Y2Ti2O7 (YTON), have been prepared by sol-gel and solid state methods respectively with urea used as a source of nitrogen for N-doping. Both of these pyrochlores were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy, energy dispersive spectra, Brunauer-Emmett-Teller surface area, Fourier transform infrared spectroscopy, and UV-visible diffuse reflectance spectroscopy. YTON crystallizes in a cubic lattice with space group . N doping in YTO lattice is substantiated by X-ray photo electron spectroscopic studies of the YTON sample. The bandgap energy of both pristine and N-doped materials is found to be 3.56 and 2.98 eV respectively from their UV-visible DRS profiles. The photocatalytic activity has been investigated by degradation of methylene blue, rhodamine B and 4-chlorophenol in aqueous solution in the presence of YTON under visible light irradiation.

Keywords: Photocatalysts, Photodegradation, Sol-gel method, Nitrogen doping, Dye degradation, Pyrochlores, Visible light

 

 

 

Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 27-34

 

 

Ultrafast radiationless decay mechanisms through conical intersections
in cytosine: Computational insight and topological analysis of the
charge density distributions

Rifaat Hilala, c, *, Saadullah G Aziza, Abdulrahman O Alyoubia & Shaaban A Elrobya, b

aChemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia

bChemistry Department, Faculty of Science, BeniSuef University, BeniSuef, Egypt

cChemistry Department, Faculty of Science, Cairo University, Cairo, Egypt

Email rhilal@kau.edu.sa

Received 26 February 2014; revised and accepted 10 December 2014

The quantum theory of atoms-in-molecules (QTAIM) in conjunction with the DFT/B3LYP/6-311++G(2d,2p) wave function are used to compute the atomic, bonded and non-bonded interactions, distributions of the charge density, r(r), and its Laplacian, 2r(r), for the ground equilibrium structure of cytosine. The study has been further extended to include two conical intersection (CI) structures that underlie the radiationless decay of cytosine. Complete Active Space Multi-configuration SCF level of theory with the 6-311++G** basis set are used to identify, characterize and to optimize the geometrical structures of the conical intersections between So and S1. In the case of cytosine, all ring bond critical points show 2r(r) < 0 indicating covalent binding and accumulation of the electron density in the bonding regions. On the other hand, the C1-O11 bond shows, depletion of charge density, indicating the increased ionic character of this bond. This point might very well underlie the reactivity and the low keto-enol barrier in cytosine. Contour plots and relief maps have been analyzed for regions of valence shell charge concentrations and depletions in the ground state and the three CI structures of cytosine. NBO analysis reveals that the conformational and overall stability of the studied cytosine conformations is facilitated by the competitive conjugative and the lone-pair interactions. In cytosine, there is a delicate balance between these two forces, whereas, in each of the two CI configurations there is one dominant force that underlies the stability of the cytosine structure. The present work indicates that the QTAIM provide not only a graphical presentation of very important critical points on the PES but also unique quantitative descriptors of CI's that characterize it.

Keywords: Theoretical chemistry, Density functional calculations, Quantum theory of atoms-in-molecules,
Conical intersections, Ultrafast radiationless decay, Electron density, Cytosine

 

Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 35-39

 

 

A two-component co-crystal of Cu(II) complex of p-tolyl-terpyridine

Dibyendu Bhattacharya

Chemistry and Biomimetics, CSIR-Central Mechanical
Engineering Research Institute, Mahatma Gandhi Avenue,
Durgapur 713 209, India

Email: dbhattacharya@cmeri.res.in

Received 11 November 2014; revised and accepted 18 December 2014

A unique two-component co-crystal, [Cu(L)(NO3)2][Cu(L)(NO3)(CH3OH)](NO3)∙H2O (L = p-tolyl-terpyridine) has been prepared in (1:1) water-methanol medium at room temperature and characterized by single-crystal X-ray diffraction analysis. The compound crystallizes in the triclinic system (space group P). The structure consists of two mononuclear Cu(II) moieties, one cationic and another neutral. In the asymmetric unit, one Cu(II) centre furnishes a five-coordinated distorted square pyramidal geometry (CuN3O2), organized by three nitrogens of L ligand and one oxygen of a monodentate nitrate anion in the equatorial position and one methanol molecule in the apical position with geometry index t5 = 0.15. The other Cu(II) centre displays a four-coordinate distorted square planar geometry (CuN3O), framed by three nitrogens of ligand L and one oxygen of a monodentate nitrate anion with geometry index t4 = 0.29 and the tetrahedral character parameter, THCDa/100 of 1.00.

Keywords: Coordination chemistry, Co-crystals, X-ray crystal structure, Copper, Terpyridine

 

Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 40-45

 

 

Kinetic and physicochemical analysis of structurally different bis-pyridinium oximes against pesticide inhibited AChE

Arvind Kumar Sahua, Bhanushree Guptaa, Rahul Sharmaa, Yama Singha, Kamil Musilekb,
Kamil Kucac & Kallol K Ghosha, *

aSchool of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur (CG) 492 010, India

Email: kallolkghosh@yahoo.com

bUniversity of Hradec Kralove, Faculty of Science, Department of Chemistry, Rokitanskeho 62, Hradec Kralove, Czech Republic

cUniversity Hospital, Biomedical Research Center, Sokolska 581, 50005 Hradec Kralove, Czech Republic

Received 13 May 2014; revised and accepted 22 December 2014

Physicochemical properties such as acid dissociation constant, pKa, and lipophilicity, log P, of some bis-pyridinium monooximes with varying functionalities in the second pyridinium ring of the reactivator have been evaluated spectrophotometrically. In vitro reactivation kinetics of the investigated oximes against paraoxon inhibited electric eel AChE has been carried out. The studied oximes have pKa values within the range of 7.85−8.38 and negative log P values, exhibiting their low lipophilic character. Further, on the basis of reactivation parameters (kr, KD, kr2) the efficacy of bis-pyridinium monooximes has been explained.

Keywords: Reactivators, Acetylcholinesterase, Paraoxon, Acid dissociation constant, Lipophilicity,
Bis-pyridinium oximes

 

Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 46-51

 

 

Synthesis of β-MnO2 nanowires and their electrochemical
capacitive behavior

Indra B Singha, * & Su-Moon Parkb,

aCSIR-Advanced Materials and Process Research Institute (CSIR-AMPRI), Bhopal 462 064, India

Email: ibsingh58@hotmail.com

bInterdisciplinary School of Green Energy Engineering, Ulsan National Institute of Science & Technology
(UNIST), Ulsan 689-805, Korea

Received 6 May 2014; revised and accepted 19 December 2015

γ-MnOOH nanowires have been synthesized using the hydrothermal process in which MnSO4 is oxidized by (NH4)2S2O8 at 130 C for 10 h in aqueous LiOH solution. The synthesized γ-MnOOH nanowires are transformed to β-MnO2 nanowires on calcination at 300 C. X-ray powder diffraction, thermal gravimetric analysis, field emission scanning electron microscopy and high resolution transmission electron microscopy examinations of the synthesized nanostructures confirm the formation of γ-MnOOH and β-MnO2 nanowires with 20-30 nm diameter and >5 m length. Electrochemical capacitive behavior of the synthesized β-MnO2 nanowires has shown specific capacitance as 404 F/m which is nearly three times higher than the capacitance reported for commercial grade MnO2 particles. Increase in calcination period from 3 h to 6 h is found to decrease the specific capacitance but increase electrochemical reactivity.

Keywords: Hydrothermal synthesis, b-Manganese dioxide, Manganese oxyhydroxide, Nanowires,
Capacitive behaviour

 

Indian Journal of Chemistry

Vol. 54A, January 2015, pp. 52-57

 

 

Influence of hydrogen bonding on the conformational stability of
calix[4]crown-4 ether

Satish Kumar*, K M Mathew, Neelam, P R Sahoo & Arun Kumar

Department of Chemistry, St. Stephens College, University Enclave, Delhi 110 007, India

Email: satish@ststephens.edu

Received 6 January 2014; revised and accepted 15 December 2014

The conformational characteristics of calix[4]crown-4 ether have been studied using different quantum mechanical methods. The structures optimized by the HF/6-31G(d), B3LYP/6-31G(d)/6-311G(d), MPW1B95/6-31G(d), MPW1PW91/6-31G(d) and M062X methods. The relative stability of different conformers follow the order: cone > partial-cone > 1,3-alternate. Short O-Hπ and intramolecular hydrogen bonds are observed in different conformers of calix[4]crown-4 ether. The relative stability of different conformers is dependent on the number and strength of intramolecular non-covalent interactions.

Keywords: Conformational stability, Hydrogen bonding, Calix[4]arenes, Calix[4]crown-4 ether