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 11

NOVEMBER 2015

 

CONTENTS

 

 

1369

 

Role of double-hybrid density functionals and correlation consistent basis sets in OCS-hydrocarbon complexes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Srimanta Pakhira, Tanay Debnath, Kaushik Sen & Abhijit K Das*

 

 

 

Five double hybrid density functionals (DHDFs) in conjunction with Dunning’s correlation consistent aug-cc-pVDZ, aug-cc-pVTZ and aug-cc-pVQZ basis sets are investigated to describe the weak interaction of the T-shaped isomer of OCS-C2H2 and OCS-C2H4 weakly bound van der Waals complexes. Amongst these, the mPW2PLYP DHDF with aug-cc-pVQZ basis set gives the best results. Both method and basis set are important for obtaining accurate results for such weakly bound complexes.

 

 

 

 

1378

 

Towards understanding mode of action of L-dopa and carbidopa: DFT/TD-DFT analyses of their electronic and vibration spectra

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ghader M Sukker, Nuha Wazzan & Rifaat Hilal*

 

 

 

Electronic absorption and vibrational spectra of L-dopa and carbidopa are recorded experimentally in different solvents and also computed theoretically. Two IR marker bands have been identified for carbidopa. Natural transition orbital analyses clearly indicate that most of the leading transitions in L-dopa and some in carbidopa involve a sizable charge transfer from the aromatic catechol moiety to the aliphatic amino acid side chain. The short wavelength transition, however, shows an opposite trend.

 

Fig-7

 

 

 

1387

 

Mechanistic study of osmium(VIII) promoted oxidation of crotonic acid by aqueous alkaline solution of potassium iodate

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bharat Singh*, Sandeep Kumar Mishra,
Shipra Tripathi & Deepmala Gupta

 

 

 

Kinetics and mechanism of osmium(VIII) promoted oxidation of crotonic acid by aqueous alkaline solution of potassium iodate have been investigated in the temperature range of 30–45 °C. A plausible mechanism involving attack of potassium iodate species on the complex formed between the catalytic species of osmium tetroxide and crotonic acid in slow and rate determining step is suggested. The rate law, consistent with observed kinetic results, is presented.

 

 

 

 

1394

 

Effect of activators and calcination on luminescence properties of ĺkermanite type phosphors

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Erkul Karacaoglu* & Bekir Karasu

 

 

 

Novel ĺkermanite type phosphors, Eu2+/3+, Dy3+, Ce3+, Pr3+/4+, Sm3+ separately-doped single-phased Ca2MgSi2O7 are synthesized by conventional solid-state reaction method under open (air) atmosphere and/or weak reducing atmosphere comprising nitrogen and hydrogen. The Ca2MgSi2O7 host structure exhibits emission of different colors due to the transitions of each doped rare earth ions. The difference in the measured emission spectra is due to
either different emission centers or same emission center
with different ionic states occupying the same host lattice.
The Ce3+-doping generates visible white light emission from the ĺkermanite type phosphor. The study shows that the rare earth ions  change the emission properties of the samples.

 

 

GA

 

 

 

 

Notes

 

1402

 

Piperazinediium bis(µ2-phthalato)zincate(II) monohydrate: A new ladder coordination polymer with a unique supramolecular architecture

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rita N Jyai & Bikshandarkoil R Srinivasan*

 

 

 

The µ2-bridging bidentate coordination modes of the crystallographically unique phthalate ligands in piperazinediium bis(µ2-phthalato)zincate(II) monohydrate result in Zn···Zn separations of 5.839(5) and 8.142(3) Ĺ respectively, leading to a
one-dimensional Zn(II) ladder. The organic cation, ladder complex anion and lattice water in (pipH2)[Zn(pt)2]·H2O assemble into
a unique supramolecular network, resulting in the water···cation···water···ladder···water  H-bonded sequence in the crystallographic ac plane.

 

Fig

 

 

 

1409

 

Ionic liquid mediated cloud point extraction of
Blue BG dye

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Darshak R Bhatt, Kalpana C Maheria &
Jigisha K Parikh
*

 

 

 

Cloud point extraction has been applied successfully for the separation of Blue BG dye using the ionic liquid, tetraethyl ammonium tetrafluoroborate, as an additive with non-ionic surfactant Triton X-100. The extraction of dye is found to increase with increase in temperature, time, surfactant concentration and ionic liquid concentration. A Langmuir type isotherm effectively describes the solubilization isotherms of the dye in TX-100.

 

 

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

 

New
 

 

 

 

 

 

 

 


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Indian Journal of Chemistry

Vol. 54A, November 2015, pp. 1369-1377

 

 

Role of double-hybrid density functionals and correlation consistent basis sets in OCS-hydrocarbon complexes

Srimanta Pakhiraa, Tanay Debnathb, Kaushik Senb & Abhijit K Dasb, *

aGraduate School of Information Science, Nagoya University, Chukusa-ku, Nagoya 464-8601, Aichi, Japan

bDepartment of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur,
Kolkata 700 032, West Bengal, India

Email: spakd@iacs.res.in

Received 21 September 2015; accepted 13 November 2015

The role of five newly developed double hybrid density functionals (DHDFs) in conjunction with Dunning’s correlation consistent aug-cc-pVDZ, aug-cc-pVTZ and aug-cc-pVQZ basis sets has been investigated to describe the weak interaction of the T-shaped isomer of OCS-C2H2 and OCS-C2H4 weakly bound van der Waals (vdW) complexes. Structure, equilibrium distances, interaction, potential energy curves and binding energy or depth of the potential well of both the complexes have been studied in detail using the DHDFs theories with these basis sets. A comparison has been made between our present results and previous theoretical and experimental values. The potential energy curves are drawn to substantiate the calculated values. Calculated equilibrium distances are the same as those reported by experiments. The components of interaction energy of both the OCS-hydrocarbon complexes are also calculated using localized molecular orbital energy decomposition analysis. The results suggest that amongst the five DHDFs only the mPW2PLYP DHDF with aug-cc-pVQZ basis set gives the best results as compared to other DHDFs. The results provide an insight into the computational methods and basis sets for such weakly bound complexes. It also reveals that both method and basis set are important to obtain accurate results for such weakly bound complexes.

Keywords:  Theoretical chemistry, Double hybrid density functionals, Correlation consistent basis set, Structural property, Potential energy surfaces, Interaction energy, Energy components, Hydrocarbon complexes, OCS-hydrocarbon complexes

 

Indian Journal of Chemistry

Vol. 54A, November 2015, pp. 1378-1386

 

 

Towards understanding mode of action of L-dopa and carbidopa:
DFT/TD-DFT analyses of their electronic and vibration spectra

Ghader M Sukkera, Nuha Wazzanb and Rifaat Hilala, b*

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

bChemistry Department, Faculty of Science, Cairo University,12613 Giza, Egypt

Email: rhilal@kau.edu.sa

Received 3 September 2015; revised and accepted 4 November 2015

The electronic absorption and vibrational spectra of L-dopa (LD) and carbidopa (CD) have been measured experimentally in different solvents and also computed theoretically. FTIR spectra of LD and CD have been computed theoretical at the B3LYP/6-311++G** level of theory. A scaling factor of 0.95 results in good correspondence between calculated and experimental spectra. Vibrational modes have been assigned and similarities and differences between the FTIR spectra of LD and CD are discussed. Two IR marker bands have been identified for CD. Based on TD-DFT/TPSSh calculations, the leading transitions contributing to the electronic absorption of LD and CD are proposed. These findings have been discussed in the context of the experimentally observed spectra reported for LD and CD in different solvents. NTO analyses clearly indicate that most of the leading transitions in LD and partially in CD involve a sizable charge transfer from the aromatic catechol moiety to the aliphatic amino acid side chain. The short wavelength transition, however, shows an opposite trend.

Keywords: Theoretical chemistry, Density functional calculations, Electronic spectra, Vibration spectra,
L-dopa, Carbidopa

 

Indian Journal of Chemistry

Vol. 54A, November 2015, pp. 1387-1393

 

 

Mechanistic study of osmium(VIII) promoted oxidation of crotonic acid by aqueous alkaline solution of potassium iodate

Bharat Singh*, Sandeep Kumar Mishra, Shipra Tripathi & Deepmala Gupta

Department of Chemistry, University of Allahabad, Allahabad 211 002, India

Email: bschem_au@yahoo.com

Received 8 September 2015; revised and accepted 30 October 2015

Kinetics and mechanism of Os(VIII) promoted oxidation of crotonic acid (CA) by alkaline solution of potassium iodate (KIO3) have been investigated at 35 °C. Zero order kinetics with respect to potassium iodate is observed. The reaction exhibits linear dependence of reaction rate at low [CA], tending towards zero order at its higher concentrations. First order kinetics with respect to catalyst osmium tetroxide (OsO4) has been observed. Accelerating effect of [OHŻ] ion on reaction rate is also observed. The reaction shows negligible effect of variation of ionic strength of the medium, while a marked effect of rise in temperature on the rate is observed. IO3- and [OsO4(OH)2]-2 are postulated as the reactive species of potassium iodate and Os(VIII), respectively. The reaction has been studied at four different temperatures (30, 35, 40 and 450C) and the overall activation parameters have been computed. A plausible mechanism conforming to the observed kinetics has been suggested. The main oxidation products have been identified as acetic acid and glyoxylic acid. A suitable mechanism involving attack of potassium iodate species on complex formed between catalytic species of osmium tetroxide and crotonic acid in the slow and rate determining step is suggested. The rate law, , is consistent with observed kinetic results.

Keywords: Kinetics, Reaction mechanisms, Oxidation, Potassium iodate, Crotonic acid, Osmium tetroxide

 

Indian Journal of Chemistry

Vol. 54A, November 2015, pp. 1394-1401

 

 

Effect of activators and calcination on luminescence properties of

ĺkermanite type phosphors

Erkul Karacaoglua, * & Bekir Karasub

aKaramanoglu Mehmetbey University, Engineering Faculty, Department of Materials
Science and Engineering, Karaman, Turkiye

Email: ekaracaoglu@kmu.edu.tr

bAnadolu University, Engineering Faculty, Department of Materials

Science and Engineering, Eskisehir, Turkiye

Received 1 October 2015; revised and accepted 27 October 2015

Ǻkermanite type Ca2MgSi2O7 phosphors activated with different types of rare earths have been synthesized through a solid state reaction method under weak reducing atmosphere and/or open atmosphere. The phase properties of the samples are characterized by X-ray diffraction and the effects of rare earth ions (Eu2+/3+, Dy3+, Ce3+, Sm3+ and Pr3+/4+) and calcinations atmosphere on the luminescence properties of the Ca2MgSi2O7 host are investigated by using a photoluminescence spectrometer. The comparative results of SEM and laser particle size analysis reveal that the relatively regular morphology, smaller particle size and narrow size distribution can be achieved for the phosphor synthesized by the solid state reaction method including dry-milling below 170 mesh. In the photoluminescence investigations, all the activator ions show different emissions for Ca2MgSi2O7 host lattice. The results show that the luminescence properties of rare earth ions activated Ca2MgSi2O7 host are also highly dependent on the calcination conditions.

Keywords: Phosphors, Ǻkermanite, Solid state reaction, Activators, Calcination, Luminescence, Rare earths

 

Indian Journal of Chemistry

Vol. 54A, November 2015, pp. 1402-1408

 

 

Piperazinediium bis(µ2-phthalato)zincate(II) monohydrate: A new ladder coordination polymer with a unique supramolecular architecture

Rita N Jyai & Bikshandarkoil R Srinivasan*

Department of Chemistry, Goa University, Goa 403206, India

Email: srini@unigoa.ac.in

Received 24 August 2015; accepted 5 October 2015

The µ2-bridging bidentate coordination modes of the crystallographically unique phthalate ligands in piperazinediium bis(µ2-phthalato)zincate(II) monohydrate (1) result in Zn···Zn separations of 5.839(5) and 8.142(3) Ĺ respectively leading to a one-dimensional Zn(II) ladder. The organic cation, ladder complex anion and lattice water in (pipH2)[Zn(pt)2]·H2O (1) (pipH2= piperazinediium, pt = phthalate) assemble into a unique supramolecular network, resulting in the following H-bonded sequence, viz., water···cation···water···ladder···water in the crystallographic ac plane.

Keywords: Coordination chemistry, Coordination polymer, Ladder complexes, Supramolecular network, Bridging ligands, Phthalates, Metal phthalates, Zinc, Zinc phthalates, Piperazinediium
bis(µ2-phthalato) zincate

 

Indian Journal of Chemistry

Vol. 54A, November 2015, pp. 1409-1413

 

 

Ionic liquid mediated cloud point extraction of Blue BG dye

Darshak R Bhatta,b, Kalpana C Maheriab & Jigisha K Parikha, *

aChemical Engineering Department, bApplied Chemistry Department, Sardar Vallabhbhai National
Institute of Technology, Surat 395 007, Gujarat, India

Email: jk_parikh@yahoo.co.in; jkp@ched.svnit.ac.in

Received 30 August 2015; accepted 13 November 2015

Cloud point extraction has been adopted for the separation of Blue BG dye using the ionic liquid, tetraethyl ammonium tetrafluoroborate, as an additive with non-ionic surfactant Triton X-100. The effects of various operating parameters such as temperature, time and concentrations of surfactant, dye and IL on extraction of dye have been studied in detail to find out the optimum conditions. The extraction of dye is found to increase with increase in temperature, time, surfactant concentration and IL concentration. The Langmuir isotherm has been used to compute the feed surfactant concentration required for the removal of Blue BG dye up to an extraction efficiency of 90%. The effects of temperature and concentration of surfactant on various thermodynamic parameters have been examined; the values of  increases with temperature and decreases with surfactant concentration. The values of  and  increase with surfactant concentration.

Keywords: Ionic liquid, Cloud point extraction, Nonionic surfactants, Blue BG, Langmuir isotherms, Thermodynamics