http://nopr.niscpr.res.in/handle/123456789/43119 Fri, 09 Oct 2026 18:33:39 GMT 2026-10-09T18:33:39Z http://nopr.niscpr.res.in/handle/123456789/43128 Title: Catalytically active network-like gold nanostructures: Synthesis and study of growth mechanism Authors: Rashid, Md. Harunar Abstract: 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 <em>p</em>-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. Page(s): 1111-1121 Wed, 01 Nov 2017 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/43128 2017-11-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/43127 Title: Studies on aggregation and counterion binding nature of didodecyldimethylammonium bromide in presence of added salts Authors: Thapa, U; Sultana, N; Ismail, K Abstract: 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. Page(s): 1122-1131 Wed, 01 Nov 2017 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/43127 2017-11-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/43126 Title: 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 Authors: Razak, N A; Fagge, I I; Khan, M N Abstract: The nucleophilic reactions of piperidine with ionized phenyl salicylate (PSa^‒) reveal a nonlinear decrease with the increase in concentration of didodecyldimethylammonium bromide (DDABr) micelles (D_n) at 35 °C and in the absence as well as presence of constant [NaBr]. The plots of pseudo-first-order rate constants (<em>k</em>_obs) versus [D_n]) have been explained quantitatively in terms of pseudophase micellar model. Such a data treatment gives DDABr micellar binding constant (<em>K</em>_S) of PSa⁻. The effects of [NaBr] upon <em>K</em>_S is explained with an empirical relationship which provides an empirical constant (<em>K</em>_Br/S where S = PSa⁻). The magnitude of <em>K</em>_Br/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. Page(s): 1132-1142 Wed, 01 Nov 2017 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/43126 2017-11-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/43125 Title: A computational study on relationship between quantum chemical parameters and reactivity of the zwitterionic GABA and its agonists: Solvent effect Authors: Serdaroğlu, Goncagül Abstract: 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. Page(s): 1143-1153 Wed, 01 Nov 2017 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/43125 2017-11-01T00:00:00Z