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 6

JUNE 2017

 

CONTENTS

 

 

585

 

Electrochemistry of binary and mixed-ligand copper(II) complexes with pyrazine and dicyanamide bridging ligands in aqueous medium

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ved Prakash*, Krishna Srivastava & Jagdish Prasad

 

 

 

Binary and mixed ligand copper(II) complexes with pyrazine and dicyanamide are synthesized in aqueous medium. The binary complex [Cu(II) (pyz)n(H2O)n] (1) shows quasi-reversible behavior, while the binary complex, [Cu(II)(dca)n(H2O)n] (2) and mixed ligand complex, [Cu(II) (dca)n(pyz)n].nH2O (3) show totally irreversible redox behavior.

 

 

 

592

 

Synthesis of α-Fe2O3 nanoparticles via wet high-energy ball-milling and its catalytic application in thermal decomposition of ammonium perchlorate

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Seyed Ghorban Hosseini*, Esmaeil Ayoman &
Azam Ghavi


 

 

Hematite nanoparticles have been successfully prepared by wet high-energy ball-milling method. These α-Fe2O3 NPs exhibit excellent catalytic effect on thermal decomposition properties of ammonium perchlorate particles.

 

 

 

Notes

 

601

 

Synthesis, structure and properties of a hexarubidium heptamolybdate with bridging aqua ligands

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bikshandarkoil R Srinivasan*, Sudesh M Morajkar, Savita S Khandolkar, Christian Näther &
Wolfgang Bensch

 

 

 

Synthesis, single crystal structure and properties of a hexarubidium heptamolybdate [Rb6(H2O)4(Mo7O24)] is reported. The bridging binding modes of the unique (Mo7O24)6- ion and the four crystallographically independent coordinated water molecules result in coordination numbers ranging from 8 to 10 for the six unique Rb(I) ions.

 

Description: C:\Users\Sudesh\Desktop\Rb_Diamond (05.01.17)\Binding mode\BITMAP\TIFF\Rb6_Binding mode_ellipsoid vdout labels.tif

 

 

 

610

 

Tuning the tripodal rotational barrier in
η6-chromiumtricarbonyl heteroarenes – A step towards torsional switches

 

 

 

 

 

 

 

 

 

 

A Kalpana & L Akilandeswari*

 

 

 

IJCA-1217 Graphical Abstract.tif

 

 

 

616

 

Synthesis and crystal structures of pyridine-2-carboxaldehyde thiosemicarbazone, its monunuclear and cytotoxic Cu(II) and polynuclear Pb(II) complexes: Effect of size of metal ion on nucleation of the complexes

 

 

 

 

 

 

 

 

 

Ayon Kanti Ghosh, Hare Ram Yadav,
Angshuman Roy Choudhury, N Duraipandian, Manikantan Symala Kiran & Rajarshi Ghosh
*

 

 

 

Fig-2.tif  Fig-3.tif

 

 

 

621

 

Polylactic acid coated SBA-15 functionalized with
3-aminopropyl triethoxysilane

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Jose Varghese, Pachiannan Sakthipriya,
Gunalan Rachel & Nallamuthu Ananthi
*

 

 

 

A new method of coating PLA on amine functionalized mesoporous silica is reported. Drug release studies with this material under different pH conditions show that mild acidic condition favours the successful release of the ibuprofen molecule.

Fig-1.tif

 

 

 

626

 

Tautomerism and non-covalent interactions of flucytosine with armchair (5,5) SWCNT and γ-Fe2O3 nanoparticles: A DFT study

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Elham Mohammad-Hasani, S Ali Beyramabadi* & Mehdi Pordel

 

 

 

Structural parameters, energetic behavior and NBO analysis of flucytosine, as well as its tautomerization mechanism are explored using DFT calculations. Due to the large HOMO-LUMO energy gap, the flucytosine molecule is highly stable, with the the most stable tautomer being F3. Non-covalent interactions of F3 with SWCNT shows the most stable form to be SWCNT-4, where the flucytosine drug is encapsulated inside the SWCNT. In its
non-covalent interactions with
γ-Fe2O3 nanoparticles, NANO-Fe1 involving three strong H-bonds is the most stable form.

 

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 585-591

 

 

Electrochemistry of binary and mixed-ligand copper(II) complexes with pyrazine and dicyanamide bridging ligands in aqueous medium

Ved Prakasha, b, *, Krishna Srivastavab & Jagdish Prasadb

aShriram Institute for Industrial Research, 19 University Road, Delhi 110 007, India

bDepartment of Chemistry, University of Allahabad, Allahabad 211 002 (UP), India

Email: ved.chem@gmail.com

Received 8 February 2017; revised and accepted 28 April 2017

The binary copper(II) complexes, viz., [Cu(II) (pyz)n(H2O)n] (1), and [Cu(II)(dca)n(H2O)n] (2), and, mixed ligand complex, [Cu(II) (dca)n(pyz)n]. nH2O (3), containing pyrazine (pyz) and dicyanamide (dca) bridging ligands (where n is number of ligand attached and it could be 1 to 6 ) are formed in aqueous medium. The electrochemical behavior of binary complexes in 1:1, 1:2 and 1:10 (Cu : pyz/dca) molar ratios and mixed ligand complex in 1: 1 :1 and 1:2:1 (Cu:dca:pyz) molar ratios have been carried out by cyclic voltammetry. The binary complex 1 undergoes a quasi-reversible single-electron redox process (Cu2+/+), while the binary complex 2 exhibits a totally irreversible reduction peak involving two electrons corresponding to Cu2+/0 change. The reduction potential becomes positive with increasing concentration of pyz/or dca, clearly indicating that reduction becomes easier with increasing concentration of ligand in binary complexes. The mixed ligand complex 3 involving pyz and dca bridging ligands shows an irreversible reduction peak assigned to Cu2+/0 electrode reactions. The UV-vis spectral properties of all the binary and mixed ligand complexes have been studied in aqueous medium.

Keywords: Electrochemistry, UV-visible spectra, Binary complexes, Bridging ligands, Copper, Pyrazine, Dicyanamide

 

 

Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 592-600

 

 

Synthesis of α-Fe2O3 nanoparticles via wet high-energy ball-milling
and its catalytic application in thermal decomposition of
ammonium perchlorate

Seyed Ghorban Hosseini*, Esmaeil Ayoman & Azam Ghavi

Department of Chemistry, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran, Iran

Email: hoseinitol@yahoo.com

Received 10 November 2016; revised and accepted 24 May 2017

α-Fe2O3 nanoparticles have been successfully produced by the wet high-energy ball-milling method. Phase and nanostructure characterizations of as-crushed powders have been done by X-ray diffraction and field emission scanning electron microscopy techniques. Average particle sizes of 56 and 51 nm are obtained after 20 and 40 hours of wet ball milling process, respectively. The catalytic property of the synthesised α-Fe2O3 nanoparticles in the thermal decomposition reaction of ammonium perchlorate has been evaluated by thermogravimetry and differential scanning calorimetry. Thermal analysis confirms that adding 5 wt.% α-Fe2O3 nanoparticles (51 nm) decreases the decomposition temperature of ammonium perchlorate from 422.0 °C to 360.0 °C and increases the ΔH of the decomposition reaction from 880 J g-1 to 1408.1 J g-1. Finally, the catalytic effects of α-Fe2O3 NPs on kinetic and thermodynamic parameters of thermal decomposition reaction of treated AP particles have been studied by Kissinger, Boswell, Ozawa and Starink methods.

Keywords: Thermal decomposition, Kinetic parameters, Thermodynamic parameters, Nanoparticles,
Wet high-energy ball-milling method, Ammonium perchlorate, Iron oxide

 

 

Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 601-609

 

 

Synthesis, structure and properties of a hexarubidium heptamolybdate with bridging aqua ligands

Bikshandarkoil R Srinivasana, *, Sudesh M Morajkara, Savita S Khandolkara,
Christian Nätherb & Wolfgang Benschb

aDepartment of Chemistry, Goa University, Goa 403206, India

Email: srini@unigoa.ac.in

bInstitut für Anorganische Chemie, Christian-Albrechts-Universität Kiel,
Max-Eyth Straße 2, D-24098 Kiel, Germany

Received 13 January 2017; revised and accepted 22 May 2017

The synthesis, single crystal structure, spectral, thermal and electrical properties of a hexarubidium heptamolybdate [Rb6(H2O)4(Mo7O24)] 1 is reported. The bridging binding modes of the unique (Mo7O24)6-
ion and the four crystallographically independent coordinated water molecules results in coordination
numbers ranging from 8 to 10 for the six unique Rb(I) ions in 1. Thermal decomposition of 1 results
in the formation of an anhydrous residue of composition 7MoO3·3Rb2O. The cyclic voltammogram
of an aqueous solution of 1 exhibits a single redox event characteristic of
(Mo7O24)6- anion.
Solution c
onductivity studies reveal the presence of hydrated Rb+ cations and uncoordinated (Mo7O24)6-
anions. A comparative study of several alkali-metal heptamolybdates reveals a rich structural chemistry in terms of the binding modes of the (Mo7O24)6- anion.

Keywords: Coordination chemistry, Rubidium, Molybdenum, Hexarubidium heptamolybdate, Bridging ligands

 

Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 610-615

 

 

Tuning the tripodal rotational barrier in η6- chromiumtricarbonyl heteroarenes – A step towards torsional switches

A Kalpana & L Akilandeswari*

Department of Chemistry, Sri Sarada College for Women, Salem 636 016, Tamil Nadu, India

Received 12 October 2016; revised and accepted 27 May 2017

The current work focuses on manifold magnification of tripodal rotational barrier of Cr(CO)3 which is haptotropically bound to the arene ring with variety of hetero substitution (boron/phosphorus). The study shows that the differential electronegativities of boron and phosphorus can be harnessed to manipulate the torsional barrier, enabling hundred 200-fold enhancement of barrier to nearly free tripodal rotation of Cr(CO)3 in arene moiety. Insights obtained by density functional studies are supported by natural bond orbital analysis.

Keywords: Tripodal rotational barrier, Tricarbonyl chromium complexes, Carbonyl complexes, Chromium, Boron, Phosphorus, Density functional calculations, Natural bond orbital analysis,
Torsional switches

 

 

 

 

 

 

 

 

 

 

Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 616-620

 

 

Synthesis and crystal structures of pyridine-2-carboxaldehyde thiosemicarbazone, its mononuclear and cytotoxic Cu(II) and
polynuclear Pb(II) complexes: Effect of size of metal ion
on nucleation of the complexes

Ayon Kanti Ghosha, Hare Ram Yadavb, Angshuman Roy Choudhuryb, N Duraipandianc,
Manikantan Symala Kiranc & Rajarshi Ghosha, *

aDepartment of Chemistry, The University of Burdwan, Burdwan 713 104, India

Email: rghosh@chem.buruniv.ac.in

bDepartment of Chemical Sciences, Indian Institute of Science Education & Research, Mohali 140 306, India

cBiomaterials laboratory, CSIR-Central Leather Research Institute, Adayar, Chennai 600 020, India

Received 20 January2017; revised and accepted 26 May 2017

Synthesis and X-ray structural characterization of pyridine-2-carboxaldehyde thiosemicarbazone (L), and its metal complexes, [Cu(L)(OH2)](ClO4)2 and [Pb(L)(ONO2)2]n are reported. X-ray diffraction reveals that the metal centres in the two complexes are distorted square planar and square pyramid geometries, respectively. Among the three compounds [Cu(L)(OH2)](ClO4)2 is found to be active against human keratinocyte cell line.

Keywords: Coordination chemistry, Thiosemicarbazones, Copper, Lead, Anticancer activity, X-ray structure

 

Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 621-625

 

 

Polylactic acid coated SBA-15 functionalized with
3-aminopropyl triethoxysilane

Jose Varghesea, Pachiannan Sakthipriyab, Gunalan Rachela & Nallamuthu Ananthib, *

aDepartment of Nanoscience and Nanotechnology, Karunya University, Coimbatore 641 114, Tamil Nadu, India

bDepartment of Chemistry, Karunya University, Coimbatore 641 114, Tamil Nadu, India

Email: write2ananthi@gmail.com

Received 4 October 2016; revised and accepted 28 May 2017

In the present study, a pH responsive polylactic acid coated SBA-15 functionalized with 3-aminopropyl triethoxysilane is reported. PLA has been coated on the functionalized SBA-15 by formation of amide linkage between amine functionalized SBA-15 and PLA. The amide linkage is confirmed by FTIR spectroscopic data. The materials are well characterized by FTIR, SEM, EDAX and XRD data. Using the PLA coated functionalized SBA-15 the controlled release of the drug ibuprofen has been studied. The successful delivery of ibuprofen has been achieved on the basis of its pH response.

Keywords: Mesoporous materials, Mesoporous silica, Silica, SBA-15, Functionalized SBA-15, Drug delivery

 

 

 

 

 

 

 

 

 

Indian Journal of Chemistry

Vol. 56A, June 2017, pp. 626-632

 

 

Tautomerism and non-covalent interactions of flucytosine with armchair (5,5) SWCNT and γ-Fe2O3 nanoparticles: A DFT study

Elham Mohammad-Hasani, S Ali Beyramabadi* & Mehdi Pordel

Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran

Email: beiramabadi@yahoo.com; beiramabadi6285@mshdiau.ac.ir

Received 22 October 2016; revised and accepted 31 May 2017

The structural parameters, energetic behavior and natural bond orbital analysis of flucytosine, as well as its tautomerization mechanism are explored theoretically using density functional theory calculations. The PCM model has been adopted to consider the solvent effects. Due to the large HOMO-LUMO energy gap, the flucytosine molecule is highly stable. The non-covalent interactions of the most stable tautomer of flucytosine with the armchair (5,5) single wall carbon nanotube and the magnetic γ-Fe2O3 nanoparticle have been explored. In each case, the most stable form is determined. Intramolecular hydrogen bonds play an essential role in stability of the non-covalent interactions between the flucytosine molecule and the γ-Fe2O3 nanoparticle.

 

Keywords: Theoretical chemistry, Density functional theory calculations, Polarizable continuum model,
Non-covalent interactions, Tautomerism,
Nanoparticles, Carbon nanotubes, Flucytosine,
Iron oxide