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 11

NOVEMBER 2017

 

CONTENTS

 

 

1111

 

Catalytically active network-like gold nanostructures:
Synthesis and study of growth mechanism

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Md. Harunar Rashid

 

 

 

Catalytically active network-like Au nanostructures are synthesized without any template under ambient conditions. Variation in HAuCl4 concentration results in formation of different types of nanostructures by the oriented attachment based self-assembly of smaller sized spherical Au nanoparticles. These nanostructures catalyze both the reduction of
p-nitrophenol and redox reaction between K3[Fe(CN)6] and Na2S2O3.

 

 

 

 

1122

 

Studies on aggregation and counterion binding nature of didodecyldimethylammonium bromide in presence of added salts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

U Thapa*, N Sultana & K Ismail*

 

 

 

The effect of counterions on the solution behavior of DDAB is studied by surface tension, fluorescence, conductance and dynamic light scattering methods. In aqueous electrolyte solution, DDAB displays two types of surface tension profiles, X and Y. Two break points are observed in the surface tension isotherms of DDAB, depending on the type and amount of added counterion.

 

FIG-5.tif

 

 

 

1132

 

Effect of [NaBr] on the rate of intramolecular base-assisted piperidinolysis of ionized phenyl salicylate in the presence of double-tail cationic surfactant aggregates: DDABr/NaBr/H2O nanoparticles catalysis

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N A Razak*, I I Fagge & M N Khan

 

 

 

The nucleophilic reaction of piperidine with ionized phenyl salicylate (PSa) reveals a nonlinear decrease with the increase in concentration of didodecyldimethylammonium bromide micelles at 35 °C and in the absence as well as presence of constant [NaBr].

 

 

 

 

1143

 

A computational study on relationship between quantum chemical parameters and reactivity of the zwitterionic GABA and its agonists: Solvent effect

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Goncagül Serdaroğlu

 

 

 

The agonist activity of zwitterionic GABA and its agonists on GABAC receptor as well as GABA uptake inhibition activity is reported. B3LYP/6-311++G(d,p) calculations have been performed to obtain the quantum chemical descriptors such as global hardness, electrophilicity, and electronic chemical potential. Polarized continuum model has been used to explore the solvent effect on activity of these compounds in four solvent media, viz., chloroform, ethanol, DMSO, and water.

 

 

GA_Corrected1.jpg

 

 

 

Notes

 

1154

 

Molecular interaction in binary mixtures of 1,4-butanediol
+picolines: Viscometric approach

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J V Srinivasu, K Narendra*, Ranjan Dey,
G Srinivasa Rao & B Subba Rao

 

 

 

Deviations in viscosity and excess Gibbs free energy of activation of viscous flow for three systems, viz., 1,4-butanediol+a-picoline, 1,4-butanediol+b-picoline and 1,4-butanediol+g-picoline in the temperature range of T = 303.15–318.15 K are reported. The deviations in viscosity are negative for all the systems under consideration. The observed values of Dh and DG*E suggest the existence of specific interactions between unlike molecules with the highest interactions being exhibited by the 1,4-butanediol+
γ-picoline system as compared to its α- and
b- systems.

 

 

 

 

1161

 

Determination of urotropine using cucurbit[7]uril-palmatine complex as a highly sensitive fluorescent probe

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chenxuan Zhang & Liming Du*

 

 

 

A new fluorescent probe with high sensitivity and selectivity has been developed for the determination of urotropine. The method is based on the competition between palmatine and urotropine for occupancy of the cucurbit[7]uril cavity that leads to fluorescence quenching. The fluorescence quenching is directly proportional to the concentration of urotropine in the range of 0.004–1.26 μg mL−1, with a detection limit as sensitive as 0.0013 μg mL−1.

 

Fig-5

 

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

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Indian Journal of Chemistry

Vol. 56A, November 2017, pp. 1111-1121

 

 

Catalytically active network-like gold nanostructures:
Synthesis and study of growth mechanism

Md. Harunar Rashid

Department of Chemistry, Rajiv Gandhi University, Rono Hills, Doimukh 791 112, Arunachal Pradesh, India

Email: mhr.rgu@gmail.com

Received 17 May 2017; revised and accepted 23 October 2017

Generation of network-like Au nanostructures by the reduction of gold ions in aqueous solution by bismuth ammonium citrate at room temperature is reported. The as-synthesized Au nanostructures have been characterized by spectroscopic, microscopic and diffractometric techniques. Microscopic results confirm that variation of HAuCl4 concentration in the reaction mixture results in the formation of different types of network-like Au nanostructures. Kinetic results indicate that these network-like Au nanostructures are formed by the oriented attachment based self-assembly of smaller sized spherical Au nanoparticles. X-ray diffraction studies reveal that the formed Au nanostructures are crystalline. These network-like Au nanostructures are catalytically active and can be used to catalyze both the reduction of p-nitrophenol and redox reaction between K3[Fe(CN)6] and Na2S2O3. Further, these network-like Au nanostructures are reusable in both types of reactions without much loss in their catalytic activity.

Keywords: Nanostructures, Self-assembly, Network-like nanostructures, Catalysts, Gold nanoparticles

 

 

Indian Journal of Chemistry

Vol. 56A, November 2017, pp. 1122-1131

 

 

Studies on aggregation and counterion binding nature of didodecyldimethylammonium bromide in presence of added salts

U Thapaa, *, N Sultanab & K Ismailb, *

aDepartment of Chemistry, School of Applied Sciences, University of Science and Technology,
Shillong 793101, Meghalaya India

bDepartment of Chemistry, North-Eastern Hill University, Shillong 793 022, Meghalaya, India

Email: uttamthapa85@gmail.com/ uttamthapa85@hotmail.com (UT); kinehu@hotmail.com (KI)

Received 25 August 2017; revised and accepted 17 October 2017

The critical micelle concentration of double chained cationic surfactant didodecyldimethylammonium bromide (DDAB) are determined in the presence of added counterions, viz., bromide, chloride and, benzoate, using surface tension, conductance and fluorescence methods. The main highlight of the article is the existence of two break-points in the surface tension isotherms of DDAB, depending on the type and amount of added counterion. At some concentrations of added counterions, normal surface tension behavior is also observed with only one break-point in the surface tension isotherm. The variation in the cmc value of DDAB with counterion concentration is studied using well-known Corrin-Harkins and modified Corrin-Harkins equations. The information gathered about the aggregation behavior of DDAB in the presence of added counterions is expected to be useful in view of DDAB’s wide utility in commercial, chemical and pharmaceutical field.

Keywords:  Solution chemistry, Aggregation behavior, Critical micelle concentration, Surface tension, Corrin-Harkins equation, Counterion binding, Surfactants, Cationic surfactants, didodecyldimethylammonium bromide

 

 

Indian Journal of Chemistry

Vol. 56A, November 2017, pp. 1132-1142

 

 

Effect of [NaBr] on the rate of intramolecular base-assisted piperidinolysis of ionized phenyl salicylate in the presence of double-tail cationic surfactant aggregates: DDABr/NaBr/H2O nanoparticles catalysis

N A Razak, I I Fagge & M N Khan

Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia

Email: iifagge@gmail.com (IIF)/ niyaz@um.edu.my (MNK)

Received 24 August 2017; revised and accepted 30 October 2017

The nucleophilic reactions of piperidine with ionized phenyl salicylate (PSa) reveal a nonlinear decrease with the increase in concentration of didodecyldimethylammonium bromide (DDABr) micelles (Dn) at 35 °C and in the absence as well as presence of constant [NaBr]. The plots of pseudo-first-order rate constants (kobs) versus [Dn]) have been explained quantitatively in terms of pseudophase micellar model. Such a data treatment gives DDABr micellar binding constant (KS) of PSa. The effects of [NaBr] upon KS is explained with an empirical relationship which provides an empirical constant (KBr/S where S = PSa). The magnitude of KBr/S is the measure of the ability of ion Br to expel the co-ion PSa from the cationic micellar pseudophase to the bulk aqueous phase. The origin of the large catalytic effect of DDABr/NaBr/H2O nanoparticles on the rate of piperidinolysis of PSa is described in terms of plausible physicochemical causes.

Keywords: Kinetics, Pseudophase micellar model, Counterion binding-micellar growth, Phenyl salicylate, Piperidine, Cationic micelles, Didodecyldimethylammonium bromide

 

 

Indian Journal of Chemistry

Vol. 56A, November 2017, pp. 1143-1153

 

 

A computational study on relationship between quantum chemical parameters and reactivity of the zwitterionic GABA and its agonists: Solvent effect

Goncagül Serdaroğlu

Faculty of Education, Cumhuriyet University, 58140 Sivas, Turkey

Email: serdaroglu@cumhuriyet.edu.tr

Received 10 November 2016; revised and accepted 24 October 2017

The agonist activity of the title compounds on GABAC receptor as well as GABA uptake inhibition activity is reported. B3LYP/6-311++G(d,p) calculations have been performed to obtain the quantum chemical descriptors such as global hardness, electrophilicity, the electronic chemical potential of the title compounds. Polarized continuum model has been used to explore the solvent effect on activity of the title compounds in four solvent media, viz., chloroform, ethanol, DMSO, and water. The results obtained from the quantum chemical calculations show that the calculated energy gap and the global hardness, as well as molecular electrostatic potential values, are in good agreement with the experimental data.

Keywords: Theoretical chemistry, Density functional calculations, Quantum chemical parameters, Global hardness, Electrophilicity, Chemical reactivity, Molecular electrostatic potential, Energy gap, Solvent effects, GABA, Chloroform, Ethanol

 

 

Indian Journal of Chemistry

Vol. 56A, November 2017, pp. 1154-1160

 

 

Molecular interaction in binary mixtures of 1,4-butanediol+picolines:
Viscometric approach

J V Srinivasua, K Narendrab, *, Ranjan Deyc, G Srinivasa Raod & B Subba Raoe

aDepartment of Basic Science, Sri Vishnu Engineering College for Women,  Bhimavaram 534 202,
Andhra Pradesh, India

bDepartment of Physics, V R Siddhartha Engineering College, Vijayawada 520 007,
Andhra Pradesh, India

cDepartment of Chemistry, BITS Pilani K K Birla Goa Campus,  Zuarinagar,
Goa 403726, India

dDepartment of Physics, Andhra Loyola College, Vijayawada 520 010,
Andhra Pradesh, India

eDepartment of Physics, VSR & NVR College, Tenali, Andhra Pradesh, India

Email: narenk75@gmail.com

Received 5 July 2017; revised and accepted 24 October 2017

The viscosity (h) of {1,4-butanediol (i) + α-, or β-, or γ-picoline (j)}binary mixtures have been measured and reported at 303.15, 308.15, 313.15 and 318.15 K over the entire range of composition. Viscosity deviation (h) and excess Gibbs energy of activation of viscous flow (∆G*E) based on Eyring’s theory have been evaluated and the results fitted to the Redlich-Kister equation. The ∆h values are observed to be negative over the entire range of composition for (1,4-butanediol+α-picoline), (1,4-butanediol+β-picoline) and (1,4-butanediol+γ-picoline) systems. The experimental viscosity data have been compared with some well-known equations of Frenkel, modified Frenkel approach and predictive ones like McAllister, Grunberg-Nissan, Hind et al., Tamura Kurata and Katti-Chaudhri. The effects of molecular sizes and shapes of the component molecules on the molecular interactions present thereof in the mixtures have been discussed.

Keywords: Solution chemistry, Thermodynamic properties, Transport properties, Viscosity, 1,4-butanediol, Picoline, Excess gibbs energy of activation, Molecular interaction, Deviation in viscosity

 

 

Indian Journal of Chemistry

Vol. 56A, November 2017, pp. 1161-1165

 

 

Determination of urotropine using cucurbit[7]uril-palmatine complex
as a highly sensitive fluorescent probe

Chenxuan Zhanga & Liming Dub, *

aDatong Institute for Food and Drug Control, Datong, Shanxi 037000, PR China

bAnalytical and Testing Center, Shanxi Normal University, Linfen, Shanxi 041004, PR China

Email: cxznihao@126.com

Received 18 September 2017; accepted 23 October 2017

A new method for sensitive and selective determination of urotropine has been developed using the cucurbit[7]uril-palmatine complex as a fluorescent probe. The complex exhibits high fluorescence in aqueous solution, which is quenched in the presence of urotropine. The fluorescence quenching value, DF, is directly proportional to the concentration of urotropine in the range of 0.004–1.26 μg mL−1, with detection limit as sensitive as 0.0013 μg mL−1. The proposed method has been successfully applied to determine urotropine in food samples with good precision and accuracy. The stoichiometry and binding affinity as well as the nature of the binding behavior are determined using spectrofluorimetry, 1H NMR and molecular modeling theoretical calculations.

Keywords: Analytical chemistry, Fluorescent probes, Urotropine, Cucurbit[7]uril, Palmatine, Competitive inclusion