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 56A

NUMBER 9

SEPTEMBER 2017

 

CONTENTS

 

 

907

 

Understanding the unfolding mechanism of human telomeric G-quadruplex using steered molecular dynamics simulation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pralok K Samanta & Swapan K Pati*

 

 

 

The unfolding pathway of human telomeric G-quadruplex with three G-tetrads in presence of K+ and Na+ ions separately, using steered molecular dynamics simulation is reported. The unfolding occurs via G-triplex intermediates, independent of the presence of cations.

 



 

 

913

 

Rhenium(I) complex with 2-(benzothiazol-2-yl) quinoline: Synthesis, characterization, spectral properties and DFT/TDDFT investigations

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rupa Sarkar, Debopam Sinha, Amit Maity &
Kajal Krishna Rajak
*

 

 

 

The red colored mononuclear Re(I) complex having fac-[Re(CO)3]+ moiety, viz., [Re(CO)3(NÇN)Cl], is synthesized in excellent yield by reacting [Re(CO)5Cl] with 2-(benzothiazol-2-yl) quinoline (1:1) in boiling mixture of methanol+chloroform (3:1, v/v) under argon atmosphere. DFT and TDDFT studies reveal the nature of excitations. The lowest lying triplet excited state is associated with the 3MLCT/3ILCT excited state. The emission-like transition is consistent with the strong 3MLCT/ 3ILCT character.

 

 

 

 

925

 

Facile synthesis of bis(indolyl)methanes over cordierite honeycomb coated with modified forms of zirconia under microwave irradiation condition

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V T Vasantha, S Z Mohamed Shamshuddin*,
Joyce Queeny D’Souza, K Shyamprasad,
S R Pratap & Venkatesh

 

 

 

Miocrowave assisted synthesis of bi(indolyl)methane over honeycomb coated with zirconia based solid acid catalysts is reported. Up to 98% yield of bis(indolyl)methane is obtained in a very short reaction time of 4 min under microwave irradiation. The honeycomb monoliths coated with modified forms of zirconia as catalytic materials are reusable for at least six reaction cycles.

 

Fig-3.tif

 

 

Notes

 

934

 

Functionalized surface for electrochemical sensing of electrochemically inactive alkali metal ion

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Urvasini Singh & Sunita Kumbhat*

 

 

 

The recognition properties of 4-aminobenzo-15-crown-5 bound to a self-assembled monolayer on the gold surface is found to be selective for Na+ ion over Li+ and K+ ions. The binding of the analyte metal ion to the ionophore has been monitored by cyclic voltammetry using redox couple Fe(CN)63-/Fe(CN)64- as a mediator redox probe.

 

Grapaphical abstract

 

 

 

939

 

Theoretical study of molecular interactions of amino acids in aqueous carbohydrate solutions by scaled particle theory

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A K Nain*, P Droliya & J Gupta

 

 

 

Solvation thermodynamics of some polar and non-polar amino acids in water and in aqueous-glucose at 298.15 K is reported. Results show that while the cavity formation for accommodation of amino acid molecules in aqueous-glucose molecules does not dependent solely on contributions from enthalpy, there is specific contribution from entropy terms. The aqueous glucose-amino acid interactions in the studied systems follow the order: l-serine < l-threonine < l-asparagine < l-glutamine in the case of polar amino acids and glycine < l-alanine < l-valine < l-methionine in the case of non-polar amino acids.

 

 

 

945

 

Thermodynamic properties of the pyrochlore Gd2Ru2O7(s) by solid oxide electrochemical cell

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Aparna Banerjee

 

 

 

The pyrochlore, Gd2Ru2O7(s), in the Gd-Ru-O system is prepared by the solid state reaction route. From elements in their
standard state, the Gibbs energy of formation of Gd2Ru2O7(s)
is: {
DfG˚(Gd2Ru2O7, s)±1.7} = –2549.1+0.6438 (T/K)×DfHo
(Gd2Ru2O7, s, 298.15 K) =  –2584 kJ mol-1.

 

 

 

 

949

 

Hydrothermal synthesis of zinc oxide nanospheres with sodium alginate as template and its photocatalytic application for degradation of diclofenac and chloramphenicol

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sarika A Shewale, Vilasrao A Kalantre & Gavisiddappa S Gokavi*

 

 

 

ZnO nanospheres of average diameter of 5.0±0.2 nm have
been prepared by a simple hydrothermal method using sodium alginate as a template. The photocatalytic activity of the ZnO nanospheres for degradation of the drugs, diclofenac and chloramphenicol, has been studied in presence of UV light of wavelength 365 nm. The total organic content of diclofenac and chloramphenicol is reduced to 12.8% and 6.8% after 180 min under the conditions of the reaction.

 

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 


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Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 907-912

 

Understanding the unfolding mechanism of human telomeric
G-quadruplex using steered molecular dynamics simulation

Pralok K Samantaa & Swapan K Patia, b, *

aTheoretical Sciences Unit, bNew Chemistry Unit, Jawaharlal Nehru Center for Advanced Scientific Research,

Jakkur PO, Bangalore 560 064, India

Email: pati@jncasr.ac.in

Received 4 July 2017; revised and accepted 18 August 2017

The unfolding pathway of human telomeric G-quadruplex with three G-tetrads in presence of K+ and Na+ ions, separately using steered molecular dynamics (SMD) simulation is reported. The isothermal-isobaric all-atoms classical molecular dynamics simulation results show that three K+ and three Na+ ions are required within the central channel of the G-quadruplex (PDB ID: 143D and 2HY9, respectively) to stabilize the respective overall structure. To obtain the unfolded G-quadruplex which is ~5-6 times of its initial contour length, SMD simulation has been carried out by fixing one end of the G-quadruplex and constraining the other end to move only along the long axis (z-axis). The SMD results suggest that the unfolding of G-quadruplex occurs via G-triplex intermediates independent of the presence of cations (K+, Na+).

Keywords: Molecular dynamics, Steered molecular dynamics, Unfolding kinetics, H-bonding, G-Quadruplex, DNA, Triplex DNA, Telomeres, Guanine

 

Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 913-924

 

Rhenium(I) complex with 2-(benzothiazol-2-yl) quinoline: Synthesis, characterization, spectral properties and DFT/TDDFT investigations

Rupa Sarkar, Debopam Sinha, Amit Maity & Kajal Krishna Rajak*

Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata 700 032, West Bengal, India

Email: kajalrajak@rediffmail.com; kkrajak@chemistry.jdvu.ac.in

Received 30 May 2016; revised and accepted 11 August 2017

The red colored mononuclear rhenium(I) complex having fac-[Re(CO)3]+ moiety of general formula, [Re(CO)3(NÇN)Cl], has been synthesized in excellent yield by reacting [Re(CO)5Cl] with 2-(benzothiazol-2-yl) quinoline (1:1) in a boiling mixture of methanol+chloroform (3:1, v/v) under argon atmosphere. Elemental, 1H and 13C NMR analysis show the formation of the desired complex. The complex is also characterized by different spectroscopic techniques. The ground and excited-state geometries, NMR, absorption, and phosphorescence properties of the Re(I) complex are examined by DFT and TDDFT methods. The natural transition orbital and spin density difference map analysis reveals the nature of excitations. The lowest lying triplet excited state is associated with the 3MLCT/3ILCT excited state. The emission-like transition is consistent with the strong 3MLCT/ 3ILCT character.

Keywords:   Coordination chemistry, Density functional calculations, Phosphorescence, Photophysical properties, 3MLCT excited state, Natural transition orbitals, Electrochemical studies, Quinoline nitrogen, Rhenium

 

Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 925-933

 

Facile synthesis of bis(indolyl)methanes over cordierite
honeycomb coated with modified forms of zirconia under
microwave irradiation condition

V T Vasanthaa, c, d, S Z Mohamed Shamshuddin*,a, c, Joyce QueenyD’Souzab, c, K Shyamprasada, S R Pratapa&Venkatesha

aChemistry Research Laboratory, HMS Institute of Technology, NH4, Kyathasandra, Tumakuru, Karnataka, India

Email: mohamed.shamshuddin@gmail.com

bDepartment of Chemistry, St. Joseph’s College, Langford Road, Bengaluru, Karnataka, India

cRegional Research Center, Visweswaraya Technological University, Bengaluru Region, Belagavi, Karnataka, India

dVemana Institute of Technology, Vemananagar, Bengaluru, Karnataka, India

Received 12 April 2017; revised and accepted 7 August 2017

Zirconia (ZrO2), Mo(VI)/ZrO2, W(VI)/ZrO2 and SO42-/ZrO2 have been coated on honeycomb monoliths and used as catalytic material in the microwave-assisted synthesis of various bis(indolyl)methane derivatives via condensation. These catalytic materials have been characterized for their properties such as surface acidity, crystallinity, morphology and elemental analysis by suitable techniques. A correlation between the acidity, crystallinity and the catalytic activity of these catalytic materials is observed. The effect of conventional heating and microwave heating on the synthesis of these derivatives has been studied. Microwave-assisted synthesis of bis(indolyl)methane derivatives over zirconia and its modified forms is found to be a fast and facile catalytic route. Up to 98% yield of bis(indolyl)methanes is obtained in a very short reaction time of 4 min under microwave irradiation, whereas it requires 20 min to obtain 98% yield under conventional heating. The honeycomb monoliths coated with modified forms of zirconia as catalytic materials are efficient, easily reactivable and reusable for at least six reaction cycles.

Keywords: Catalysts, Monoliths, Honeycomb monoliths, Microwave assisted synthesis, Bis(indolyl)methanes, Zirconia, Modified zirconia, Molybdenum, Tungsten, Sulphate

 

Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 934-938

 

Functionalized surface for electrochemical sensing of electrochemically
inactive alkali metal ion

Urvasini Singh &SunitaKumbhat*

Biosensor Laboratory, Department of Chemistry,
JNV. University, Jodhpur342033, India

Email: skumbhat@rediffmail.com

Received 18 July 2017, revised and accepted 24 August 2017

The binding of Na+ ion to the ionophore 4-aminobenzo-crown-5 has been monitored by cyclic voltammetry using the redox couple Fe(CN)63-/Fe(CN)64- as a mediator redox probe. The recognition properties of the ionophore covalently bound to 11-MUA self assembled monolayer on gold surface is found to be selective for Na+ ion over Li+ and K+ ions.The self-assembled sensor interface is highly stable, reproducible and shows good sensitivity for detection of Na+ ion. The host-guest recognition of the simple crown ether derivative makes the system highly promising for real-time applications for selective detection of electrochemically inactive alkali metals by electrochemical transducer.

Keywords: Electrochemical sensors, Sensors, Cyclic voltammetry, Host-guest complexation, Self assembled monolayers, Alkali metals, Sodium

 

Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 939-944

 

Theoretical study of molecular interactions of amino acids in aqueous carbohydrate solutions by scaled particle theory

A K Nain*, P Droliya & J Gupta

Department of Chemistry, Dyal Singh College (University of Delhi), New Delhi 110 003, India

Email: ak_nain@yahoo.co.in

 

Received 5 January 2017; revised and accepted 24 August 2017

The scaled particle theory (SPT) has been applied to study solvation thermodynamics of some polar and non-polar amino acids (l-serine, l-threonine, l-asparagine, l-glutamine, glycine, l-alanine, l-valine, l-methionine) in water and in aqueous-glucose (5% d-glucose, w/v in water) at 298.15 K. The solvation free energy (ΔGSolv), enthalpy (ΔHSolv) and entropy (ΔSSolv) of amino acids in aqueous-glucose have been calculated using SPT from various contributions. The results show that the major contribution to thermodynamic parameters is from the interactions between the participating components. While the cavity formation for accommodation of amino acid molecules in aqueous-glucose molecules does not dependent solely on contributions from enthalpy, there is specific contribution from entropy terms. The results also indicate that the interactions in the studied systems follow the order: l-serine < l-threonine < l-asparagine < l-glutamine in the case of polar amino acids; and glycine < l-alanine < l-valine < l-methionine in case of non-polar amino acids.

 

Keywords: Solution chemistry, Scaled particle theory, Amino acids, Carbohydrates, Solvation thermodynamics

 

Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 945-948

 

Thermodynamic properties of the pyrochlore Gd2Ru2O7(s) by
solid oxide electrochemical cell

Aparna Banerjeea, b

aHomi Bhabha National Institute (Chemistry), Mumbai 400 094, India

bFCD, RC&I Group, Bhabha Atomic Research Centre, Mumbai 400 085, India

Email: aparnab@barc.gov.in/ aparna_baner@yahoo.com

Received 12 June 2016; revised and accepted 28 August 2017

Gibbs energy of formation of Gd2Ru2O7(s) has been determined using solid state electrochemical technique employing oxide ion conducting electrolyte. The reversible electromotive force of the following solid-state electrochemical cell, (-)Pt/{Gd2O3(s)+Gd2Ru2O7(s)+ Ru(s)}//CSZ//O2(p(O2) = 21.21 kPa)/ Pt(+) has been measured. The Gibbs energy of formation of Gd2Ru2O7(s) from elements in their standard state, calculated by the least squares regression analysis of the data obtained in the present study, is represented by: {f GO (Gd2Ru2O7, s)/(kJ mol-1) 1.7} = – 2549.1 + 0.6438(T/ K); 1030.9 T/K 1193.6. The second law method gives the value of standard molar enthalpy of formation of the compound from the elements at 298.15K.

Keywords: Pyrochlores, Electrochemical cells, Oxides, Rare earth ruthenates, Ruthenates, Thermodynamic parameters, Gibbs energy of formation

 

Indian Journal of Chemistry

Vol. 56A, September 2017, pp. 949-954

 

Hydrothermal synthesis of zinc oxide nanospheres with sodium alginate as template and its photocatalytic application for degradation of diclofenac and chloramphenicol

Sarika A Shewalea, Vilasrao A Kalantrea &
Gavisiddappa S Gokavib, *

aDepartment of Chemistry, Balasaheb Desai College, Patan 415 206, Maharashtra, India

bDepartment of Chemistry, Shivaji University, Kolhapur 416 004, India

Email: gsgokavi@hotmail.com

 

ZnO nanospheres of average diameter of 5.0±0.2 nm have been prepared by simple hydrothermal method using sodium alginate as a template. The prepared ZnO nanospheres are characterized by XRD, TEM, EDX and fluorescence spectra. The photodegradation of the drugs diclofenac (DCF) and chloramphenicol (CHL) are studied in presence of UV light of wavelength 365 nm. Formation of wurtzite structure of ZnO nanospheres is confirmed by XRD analysis. The decrease in intensity of fluorescence emission spectra of the nanospheres indicated the interaction between the drug molecules and the excited species. The peroxide radicals and the hydroxyl radicals formed due to electron and the hole further affect the degradation of the drug molecules. The TOC content of DCF and CHL is reduced to 12.8% and 6.8% after 180 min under the conditions of the reaction.

 

Keywords: Photodegradation, Hydrothermal synthesis, Zinc oxide nanospheres, Diclofenac, Chloramphenicol