Alternative Approach to Synthesis of 3-(4-chloro butyl)-1H-indole-5-carbonitrile: A Key Intermediate of Vilazodone Hydrochloride,an Antidepressant Drug

An alternative and efficient telescopic approach to the synthesis of 3-(4-chloro butyl)-1H-indole -5-carbonitrile (2), a key intermediate in the synthesis of vilazodone hydrochloride (1), is described.     

Simultaneous determination of titanium and molybdenum in steel samples using derivative spectrophotometry in neutral micellar medium

A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of Ti(IV) and Mo(VI) using resacetophenone p-hydroxybenzoylhydrazone (RAPHBH) in presence of Triton X-100, without any prior separation. Beer's law is obeyed between 0.13-1.2 microg mL-1 and 0.18-1.90 microg mL-1 concentration of Ti(IV) and Mo(VI) at 455 nm and 405 nm, respectively. The molar absorptivity and Sandell's sensitivity of the coloured complexes at pH 3.0 are 3.1x10(4) L mol-1 cm-1, 4.2x10(4) L mol-1 cm-1, and 1.6 ng cm-2, 2.3 ng cm-2 for Ti(IV) and Mo(VI), respectively. The stoichiometry of the complexes were found to be 1:2 and 1:1 (metal:ligand) for Ti(IV) and Mo(VI), respectively. These metal ions interfere with the determination of each other in zero-order spectrophotometry. The first derivative spectra of these complexes permitted a simultaneous determination of Ti(IV) and Mo(VI) at zero crossing wavelengths of 500.0 nm and 455.0 nm, respectively. The effect of foreign ions in the determination of Ti(IV) and Mo(VI) were investigated. The proposed method has been successfully applied for the determination of titanium and molybdenum in standard alloy steel, mineral and soil samples.     

Influence of oxygen atmosphere on the photoluminescence properties of sol–gel derived ZrO2 thin films

Homogeneous and transparent ZrO₂ thin films were prepared by sol?Cgel dip coating method. The prepared ZrO₂ thin films were annealed in air and O₂ atmosphere at 500, 700 and 900?°C for 1, 5 and 10?h. X-Ray diffraction (XRD) pattern showed the formation of tetragonal phase with a change of stress in the films. Scanning electron microscope (SEM) revealed the nucleation and particle growth on the films. An average transmittance of >80?% (in UV?CVis region) was observed for all samples. The refractive index and direct energy band gap were found to vary as functions of annealing atmosphere, temperature and time. Photoluminescence (PL) revealed an intense emission peak at 379?nm weak emission peaks at 294, 586 and 754?nm. An enhancement of PL intensity was observed in films annealed in O₂ atmosphere. This is due to reconstruction of zirconium nanocrystals interfaces, which help passivate the non-radiative defects. At 900?°C, oxygen atoms react with Zr easily at the interface and destroy the interface states acting as emission centres and quench the PL intensity of the film. The enhancement of the luminescence properties of ZrO₂ by the passivation of non radiative defects presents in the films make it suitable for gas sensors development, tuneable lasers and compact disc (CD) read-heads.     

Approaches for modelling of industrial energy systems: correlation of heat transfer characteristics between magnetohydrodynamics hybrid nanofluids and performance analysis of industrial length-scale heat exchanger

Journal of Thermal Analysis and Calorimetry - Numerical analysis is carried out on heat transfer performance of industrial-length double-tube heat exchanger, by using hybrid nanofluid as a coolant...     

Pyridoxinium picrate

The title compound [systematic name: 3‐hydr­oxy‐4,5‐bis­(hydroxy­meth­yl)‐2‐methyl­pyridinium 2,4,6‐trinitro­phenolate], C₈H₁₂NO₃⁺·C₆H₂N₃O₇⁻, is a complex of picric acid with pyridoxine. The asymmetric part of the unit cell contains one pyridoxinium cation and one picrate anion. The aromatic rings of the picrate anion and the pyridoxinium cation are inclined with a dihedral angle of 83.19 (7)°. An intra­molecular hydrogen bond between OH and a nearby CH₂OH group is observed in the cation. The hydro­phobic layers at y = are packed between the hydro­philic layers at y = 0.     

Salicylaldimine-based symmetric dimers: synthesis and thermal behaviour

Several symmetrical dimers comprised of salicylaldimine-moieties connected through ester linkages to the termini of odd-parity alkanediols have been synthesized and investigated for their thermal behaviour. In order to understand the structure-property relations, the lengths of the central alkylene spacers (C₃ and C₅) as well as those of the terminal alkoxy chains (C₆ to C₂₂) have been varied. The dimers with a C₃-alkylene spacer are non-liquid crystalline, while some of the compounds having a C₅-alkylene spacer exhibit liquid crystalline properties. The dimer, with a C₅-alkylene spacer and C₆-alkoxy tails, shows an intercalated smectic C (SmC_c) phase, whereas the C₈, C₁₀, C₁₁, and C₁₂ homologues are non-mesomorphic. The higher homologues of this series with C₁₆, C₁₈, C₂₀ and C₂₂ alkoxy tails show a mesophase that has the signatures of a two-dimensional banana (B₁) phase. This mesophase is enantiotropic in the C₁₆ and C₁₈ homologues while it is monotropic in the other homologues. In these dimers, the spacer length has a remarkable influence on the thermal behaviour.     

First Stereoselective Total Synthesis of Gallicynoic Acids G and H

A stereoselective convergent total synthesis of two acetylenic acids, gallicynoic acid G ( 1 ) and H ( 2 ), is reported, involving asymmetric reduction of alkynones 3 and 4 , respectively, with the Corey? Bakshi? Sibata (CBS) catalyst as a key step (Scheme 3), 3 and 4 being obtained from a common intermediate, the chiral alkynol 12 (Scheme 2).     

Persistence and coexistence of infinite attractors in a fractal Josephson junction resonator with unharmonic current phase relation considering feedback flux effect

Josephson junction resonators are the devices which exhibit complex behaviours as a consequence of their inductive properties. Even though the insulating medium between Josephson junctions (JJs) is normally considered homogeneous, the fact that lithography is used to form the layer, it has fractal substrates. Such JJs are identified as fractal Josephson junctions (FJJs). In this paper, a new chaotic oscillator based on memristor and FJJ has been investigated. Superconductor properties can dramatically change its operating points especially voltage and heat that are related to Josephson tunnelling. Some changes in the operating points can cause the Josephson tunnelling junctions to oscillate in different oscillation modes in very high frequencies. This can be achieved by considering the potential across the junction with its flux feedback. In order to model the magnetic flux effect, we use a memristor whose memductance function is considered as an exponential function. By varying the type of the bias current, we could observe the property of infinitely coexisting attractors in the memristor-fractal Josephson junction oscillator, which is considered as a rare phenomenon in physical circuits. The proposed Josephson-Memristor circuit model is developed, and its equilibrium points, bifurcation and Lyapunov exponents are computed. As an engineering application, modelling the trajectories of the moving object has been realized. First, the SURF algorithm, which is not affected by the scale and rotations of the object, is used in the images to identify an object that tracks the states of the proposed Josephson-Memristor circuit. In this way, the coordinates of the orbits on which the object moves were determined on the image. In order to reproduce the orbits of the specified object, the coordinate information of the object has been trained to the artificial neural network model and the orbits of the object have been reproduced.

     

Unsymmetrical trimesogens exhibiting the undulated twist grain boundary (UTGBC*) mesophase

A new set of trimesogens consisting of a cholesteryl ester, a biphenyl and an azobenzene mesogenic segment joined together through either odd-even, even-even or odd-odd central alkylene spacers has been synthesized and the liquid crystalline properties investigated. The trimesogens having even-even and odd-odd central alkylene spacers exhibit the undulated twist grain boundary phase (UTGBC*) mesophase over a temperature range of ~40-50°C.