Liquid-liquid equilibrium in the toluene-methyl ethyl ketone-water system

For the toluene-methyl ethyl ketone-water system the liquid-liquid equilibrium tie-line data have been determined at 40 and 0°C and the binodal curve for this system has been determined at 40, 0 and −10°C. The tie-line data at 40 and 0°C could be correlated with good accuracy using NRTL and UNIQUAC model equations.     

Cocatalysis by ruthenium(III) in hydrogen ions catalyzed oxidation of iodide ions: A kinetic study

RuCl₃ further catalyzes the oxidation of iodide ion by K₃Fe(CN)₆, already catalyzed by hydrogen ions. The rate of reaction, when catalyzed only by hydrogen ions, was separated graphically from the rate when both Ru(III) and H⁺ ions catalyzed the reaction. Reactions studied separately in the presence as well as absence of RuCl₃ under similar conditions were found to follow second‐order kinetics with respect to [I^?], while the rate showed direct proportionality with respect to [Fe(CN)₆]^3?, [RuCl₃], and [H⁺]. External addition of [Fe(CN)₆]^4? ions retards the reaction velocity, while changing the ionic strength of the medium has no effect on the rate. With the help of the intercept of the catalyst graph, the extent of the reaction that takes place without adding Ru(III) was calculated and it was in accordance with the values obtained from the reaction in which only H⁺ ions catalyzed the reaction. It is proposed that ruthenium forms a complex, which slowly disproportionates into the rate‐determining step. Arrhenius parameters at four different temperatures were also calculated. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 545–553, 2004     

Data acquisition techniques in digital photoelasticity: a review

Advancements in the last two decades for data acquisition in digital photoelasticity have been brought out in this paper. Photoelasticity is an engineering tool and as an end user, one would like to know which of the techniques to be selected for a particular application. With this in view, the various techniques are reviewed and a brief summary of the steps involved in each of the techniques are also given. A need to capture the images in colour is indicated for full automation of data acquisition. Future directions of research in digital photoelasticity is also highlighted.     

Growth and characterization of thiosemicarbazide hydrochloride: a semiorganic NLO material

Thiosemicarbazide hydrochloride (TSCHCL) was synthesized by mixing thiosemicarbazide and hydrochloride in 1:1 molar ratio in double distilled water. Single crystals of TSCHCL were grown by slow evaporation at room temperature and were characterized by single crystal X-ray diffraction study to determine the molecular structure and by FT-IR, ¹H and ¹³C NMR spectral analyses to confirm the synthesized compound. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. The transmission spectrum of TSCHCL showed that the crystal is transparent in the wavelength range 380–1100 nm. High resolution X-ray diffractometry (HRXRD) was employed to evaluate the perfection of the grown crystal. Mechanical properties of the grown crystal were studied using Vickers microhardness test. Second harmonic generation efficiency of the powdered TSCHCL was tested using Nd:YAG laser and is ∼1.5 times that of potassium dihydrogen orthophosphate.     

Crystal structure of nonadentate tricompartmental ligand derived from pyridine-2,6-dicarboxylic acid: Spectroscopic, electrochemical and thermal investigations of its transition metal(II) complexes

The coordinating behavior of a new dihydrazone ligand, 2,6-bis[(3-methoxysalicylidene)hydrazinocarbonyl]pyridine towards manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) has been described. The metal complexes were characterized by magnetic moments, conductivity measurements, spectral (IR, NMR, UV-Vis, FAB-Mass and EPR) and thermal studies. The ligand crystallizes in triclinic system, space group P-1, with α=98.491(10)°, β=110.820(10)° and γ=92.228(10)°. The cell dimensions are a=10.196(7)?, b=10.814(7)?, c=10.017(7)?, Z=2 and V=1117.4(12). IR spectral studies reveal the nonadentate behavior of the ligand. All the complexes are neutral in nature and possess six-coordinate geometry around each metal center. The X-band EPR spectra of copper(II) complex at both room temperature and liquid nitrogen temperature showed unresolved broad signals with g(iso)=2.106. Cyclic voltametric studies of copper(II) complex at different scan rates reveal that all the reaction occurring are irreversible.     

Synthesis, spectral characterization and biological activities of Mn(II) and Co(II) complexes with benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone

Mn(II) and Co(II) complexes of benzyloxybenzaldehyde-4-phenyl-3-thiosemicarbazone have been synthesized and characterized by the investigations of electronic and EPR spectra and X-ray diffraction. Based on the spectral studies, an octahedral geometry is assigned for the Mn(II) and Co(II) complexes. X-ray powder diffraction studies reveal that Mn(II) and Co(II) complexes have triclinic crystal lattices. The unit cell parameters of the Mn(II) complex are a=11.0469 ?, b=6.2096 ?, c=7.4145 ?, α=90.646°, β=95.127°, γ=104.776°, V=489.7 ?(3) and those of Co(II) complex are a=9.3236 ?, b=10.2410 ?, c=7.8326 ?, α=90.694°, β=99.694°, γ=100.476°, V=724.2 ?(3). When the free ligand and its metal complexes are subjected to antibacterial activity, the metal complexes are proved to be more active than the ligand. However with regard to in vitro antioxidant activity, the ligand exhibits greater antioxidant activity than its metal(II) complexes.     

Investigation of hydrogen absorption in Li7VN4 and Li7MnN4

The hydrogen storage properties of Li(7)VN(4) and Li(7)MnN(4) were investigated both by experiment and by density functional theory calculations. Li(7)VN(4) did not sorb hydrogen under our experimental conditions. Li(7)MnN(4) was observed to sorb 7 hydrogen atoms through the formation of LiH, Mn(4)N, and ammonia gas. An applied pressurized mixture of H(2)/Ar and H(2)/N(2) gases was helpful to mitigate the release of NH(3) but could not prevent its formation. The introduction of N(2) also caused weight gain of the sample by re-nitriding the absorbed products LiH and Mn(4)N, which correlated with the presence of Li(2)NH, LiNH(2), and Mn(2)N detected by X-ray diffraction. While our observed results for Li(7)VN(4) and Li(7)MnN(4) differ in detail, they are in overall qualitative agreement with our theoretical work, which strongly suggests that both compounds are unlikely to form quaternary hydrides.     

Synthesis of spirocyclic thiazolidinediones using ring-closing metathesis and one-pot sequential ring-closing/cross metathesis

A novel synthetic route to spirocyclic thiazolidinediones is reported by utilizing ring-closing metathesis (RCM). A selective cross metathesis (CM) of N-allyl azaspiro derivatives with different olefins has been demonstrated to prepare substituted azaspiro-[4.4]nonenediones. The X-ray crystal structure of a spirocyclic thiazolidinedione dimer is described, which has been prepared in two steps from thiazolidinedione using a one-pot sequential ring-closing and self metathesis. Cross metathesis proceeds smoothly with both electron rich and poor olefins. The symmetrical bis-thiazolidinedione spirocyclic system can be used as CM coupling partner with olefins. One-pot sequential RCM-CM has been developed for the synthesis of substituted spirocyclic compounds. The methodology allows a quick access to thia-azaspiro-[4.4]nonene and -[4.5]decene-dione ring systems from readily available starting materials which are not otherwise accessible.