http://nopr.niscair.res.in/handle/123456789/7344 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/7352 Title: A kinetic study on Ru(III)–catalysed oxidation of mercaptosuccinic acid by methylene blue in acidic medium <br/> <br/>Authors: Mishra, K K; Chaturvedi, Ranu; Shukla, M <br/> <br/>Abstract: Mercaptosuccinic acid and methylene blue interact in a molar ratio of 2:1 in presence of hydrochloric acid and Ru(III) as a catalyst in aqueous acetone medium (40% <i style="">v/v</i>) forming dithiodimalic acid and dihydromethylene blue. The reaction follows a half order kinetics in methylene blue. The order in mercaptosuccinic acid is unity. The average value of half order rate constant remains practically unaffected on varying [H⁺] up to 2.0 × 10^-2 <i>M</i>. The order in methylene blue changes from 1/2 to 1 at lower [H⁺] (1.0 × 10^-2 <i>M</i>)as well as at lower concentrations of catalyst (1.0 × 10^-5 <i>M</i>), while at higher [Ru (III)] (≥ 2.0 × 10^-5 <i>M</i>) the order in the oxidant becomes zero. This indicates that the relationship between the rate constant and [Ru(III)] is not simple. The rate constant decreases on increasing the time of equilibration of Ru(III) with other ingredients of the reaction system. SEM images suggest the formation of square shaped crystals with size ranging between 50-200 μm. The addition of reaction products does not influence the rate. Activation parameters have been evaluated and a plausible reaction scheme, presuming the reaction between the transient complex (Ru(III)SR’)and MBH⁺ as the rate determining step, has been proposed. <br/> <br/>Page(s): 185-189 Fri, 29 Jan 2010 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/7351 Title: Prediction of viscosity for R142b, R152a at the zero density regime by a semi-empirical method <br/> <br/>Authors: Haghighi, Behzad; Heidari, Fatemeh; Papari, Mohammad Mehdi <br/> <br/>Abstract: An new inversion method is presented for obtaining the interaction potential pairs for 1-choloro-1,1-difluoroethane and 1,1-difluoroethane utilizing the extended corresponding states approach of Huber <i style="">et al.</i> [Huber M L, Laesecke A, Perkins R A, <i>Ind Eng Chem Res</i>, 42 (2003) 3163]. The calculated inverted potentials have been used in evaluating the viscosity coefficients for gaseous state of both the compounds in dilute gas density regime. Due to the iterative nature of the present method the Lennard-Jones 12-6 (LJ 12-6) potential model has been implemented initially. The interaction potential energies from the inversion method reproduce the viscosity and are commensurate within the uncertainty of the best measurements which can be applied to a wide span of temperature range. The reduced collision integrals and their ratios have also been estimated. <br/> <br/>Page(s): 180-184 Fri, 29 Jan 2010 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/7350 Title: A DFT and AIM study of the interactions of pyridine and pyrazine with alkali hydrides. Identification of dihydrogen bonds involving aromatic C-H hydrogen <br/> <br/>Authors: Samanta, Amit K; Datta, Dipankar <br/> <br/>Abstract: The interactions of pyridine (py) and pyrazine (pz) with LiH, NaH and KH are studied by DFT at the B3LYP/6-311++g(2d,p) level. The interaction energies corrected for BSSE lie in the range −86.7 to −38.8 kJ mol^-1. Dihydrogen bonds are observed only for the py-KH and pz-KH systems with distances 2.27 and 2.17 Å respectively. AIM analyses show presence of bond critical points, associated with an electron density of 0.011-0.013. Our calculations on the ammonia borane dimer, where presence of dihydrogen bond is authentic, at the same level of theory reveal that the electron density at the bond critical points of the dihydrogen bonds (of calculated lengths 2.03-2.05 Å) is 0.015. <br/> <br/>Page(s): 176-179 Fri, 29 Jan 2010 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/7349 Title: Synthesis, characterization and ferromagnetic behavior of [Co^III(en)₂(RC₆H₄NH₂)I]I₂.H₂O complexes <br/> <br/>Authors: Anbalagan, K; Ganeshraja, A S; Kandasamy, S <br/> <br/>Abstract: Mixed ligand cobalt(III) complexes containing aryl amine (RC₆H₄NH₂) ligand have been synthesized using a modified route developed in this study. A wide range of complexes, [Co^III(en)₂(L)I]I₂.H₂O, (where L = RC₆H₄NH₂; R = <i style="">m</i>-OMe, <i style="">p</i>-F, H, <i style="">m</i>-Me, <i style="">p</i>-Me, <i style="">p</i>-OEt and <i style="">p</i>-OMe) show promising reactivities and physical properties due to the presence of electron donor/acceptor groups in the aryl ligand. The complexes have been characterized by elemental analysis, FT-IR, UV-vis and powder X-ray diffraction patterns. FT-IR ν(M-X) and UV-vis spectral data are compatible with <i style="">trans-</i>form of the complexes. Magnetic studies yield magnetic remanence <i style="">M_r</i> = 7.071 ´ 10^-3 – 3.069 ´ 10^-5 emu/g and intrinsic coercivity, -<i style="">H_ci</i> = 141-1156 Oe. Linear regression plot of <i style="">M_r</i> versus σ yields negative slope, implying that electron withdrawing group in RC₆H₄NH₂(σ > 0) enhances ferromagnetic character while the electron donating groups (σ < 0) reduce ferromagnetism. The study provides evidence that substitution at the aryl ligand, remote from the Co(III) center, effectively displays and imparts characteristic ferromagnetic properties. Cobalt(III) complexes containing RC₆H₄NH₂ligand illustrate a simple molecular fabrication technique, which can be suitably integrated into a system, to have some control on the behavior of metal complexes. A modified ferromagnetic character due to charge build up on the metal centre by ligating nitrogen atom, which in turn makes the molecule into a centre of systematic variation in magnetization, has been observed. <br/> <br/>Page(s): 171-175 Fri, 29 Jan 2010 22:58:59 GMT