http://nopr.niscair.res.in/handle/123456789/795 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/2233 Title: Simple anion receptor with imidazole and phenol groups: Forming hydrogen-bond complex with Cl⁻ <br/> <br/>Authors: Chen, Huamei; Lin, Hai; Cai, Zunsheng; Lin, Huakuan <br/> <br/>Abstract: A simple anion receptor 2'-(2"-hydroxy-3"-methoxyphenyl)imidazo[4',5'-f]-1, 10-phenanthroline[5,6-f] (1) with imidazole and phenol groups has been synthesized and its interaction investigated with anions (F⁻, Cr⁻, Br⁻, I⁻, AcO⁻ and H₂PO₄⁻) by UV -vis and ¹H NMR titrations. Added with Cl⁻, the change of UV -vis spectra of 1 is different from that of added AcO⁻,F⁻ and H₂PO₄⁻. Also, the change of ¹H NMR titration spectra of 1 with Cl⁻ is different from that of added AcO⁻, F⁻ and H₂PO₄⁻, 1 forms supramolecular complex with Cl⁻ as a receptor and is deprotonated with AcO⁻, F⁻ and H₂PO₄⁻ as a colormetric sensor. The receptor forms H-bond complex with Cl⁻ by NH of imidazole, Hc' of phenanthroline and H₁ of phenyl. As an acid proton donor, the protons of NH of imidazole and OH of phenol are too acidic to form hydrogen-bond complex with AcO⁻, F⁻ and H₂PO₄⁻. So, the interaction of 1 with AcO⁻, H₂PO₄⁻ and F⁻ is acid-basic reaction. The affinity to anions of NH is dramatically more powerful than that of OH. <br/> <br/>Page(s): 748-754 http://nopr.niscair.res.in/handle/123456789/1199 Title: Densities, viscosities, viscosity deviations and excess thermodynamic properties of binary liquid mixtures of diethyl oxalate and dimethyl malonate with polar and non-polar solvents at 303.15 K <br/> <br/>Authors: Diwedi, Archana; Singh, Mukhtar <br/> <br/>Abstract: Densities and viscosities have been measured for the binary liquid mixtures of diethyl oxalate and dimethyl malonate with some polar and non-polar solvents, viz. ethanol, acetone, chloroform, carbon tetrachloride, benzene and toluene over the entire composition range at 303.15 K. From density and viscosity data, the values of viscosity deviations (Δη) and excess thermodynamics properties, viz. the excess molar volumes (VE) and the excess Gibbs free energies of activation of viscous flow (ΔG#E) of the binary mixtures have been determined at 303.15 K. The values of , VE and ΔG#E have been fitted to Redlich-Kister polynomial equation to estimate the binary coefficients and standard deviation between the experimental and computed values. On correlating the viscosities of the binary liquid mixtures with the equations of Nissan-Grunberg and McAllister, it is concluded that the viscosities are best correlated with McAllister equation. <br/> <br/>Page(s): 789-794 http://nopr.niscair.res.in/handle/123456789/1198 Title: Kinetic investigation of the reactions between triphenylphosphine, dialkyl acetylenedicarboxylates and NH-acid such as 7-azaindole by the UV spectrophotometry <br/> <br/>Authors: Khorassani, S M Habibi; Maghsoodlou, M T; Ebrahimi, A; Roohi, H; Zakarianezhad, M <br/> <br/>Abstract: Kinetic studies of the reactions between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of NH-acid, such as 7-azaindole are reported here. Kinetic parameters of the reactions have been monitored by UV spectrophotometery. The second order fits have been automatically drawn and the values of the second order rate constant (k₂) calculated using standard equations within the program. At the temperature range studied, dependence of second order rate constant (Ln k₂) on reciprocal temperature is in agreement with Arrhenius equation. This provides the relevant plots to calculate the activation energy of all reactions. Studies on the effect of solvent, structure of reactants (different alkyl groups within the dialkyl acetylenedicarboxylates) and also concentration of reactants on the rate of reactions have been made. Proposed mechanism has been confirmed according to the obtained results and steady state approximation and first step (k₂) of reaction recognized as the rate determining step on the basis of experimental data. <br/> <br/>Page(s): 783-788 http://nopr.niscair.res.in/handle/123456789/1197 Title: Electrochemical behaviour of Ni(II) l-amino acid in aqueous dimethylformamide, N-methyl formamide and formamide media at dme <br/> <br/>Authors: Bairwa, B S; Goyal, Monika; Sharma, I K; Varshney, S; Verma, P S <br/> <br/>Abstract: Polarographic technique has been used to evaluate the kinetic parameters and formation constants of Ni(II) complexes with l-arginine, l-lysine, l-tryptophan, l-tyrosine, l- aspartic acid and l- glutamic acid at pH 8.40±0.20 and constant ionic strength (μ= 0.1) NaClO₄ in aqueous DMF, N-methyl formamide and formamide mixture at d.m.e. The reduction of all these complexes is found to be irreversible and hence the kinetic parameters (K⁰fh, ⍺n,ξ) of these complexes have been calculated using Meites-Israel method and its modification by Gaur and Bhargava. In all the cases a single reduction wave is obtained but in the case of Ni(II) l-lysine complex in N-methyl formamide, two waves are obtained. This could possibly be due to the fact that the complex may have split in solution forming the aquo nickel complex, which reduces at sufficiently negative potential to the corresponding complex. One wave is found to be diffusion controlled while the other is a kinetic wave. <br/> <br/>Page(s): 778-782