Mesomorphic and DFT studies of terminal ester containing salicylaldimines and their copper (II) complexes

In this article, we report synthesis and characterization of a novel homologous series of butyl 4-(4′-(alkoxy)-2-hydroxybenzylideneamino)benzoates, C_nLH (n = 6, 8, 10, 12, 14, 16) and their copper(II) complexes. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and powder X-ray diffraction (XRD) studies. The ligands and their copper(II) complexes exhibit wide range of enantiotropic smectic A mesophase as confirmed by their typical optical texture under polarizing microscope. Thermal stability of the compounds is determined by thermo gravimetric analyses. DFT calculations have been performed using GAUSSIAN-09 program at B3LYP level to obtain the stable electronic structure of the ligand and its copper(II) complex.     

Photo and electrically switchable behavior of azobenzene containing pendant bent‐core liquid crystalline polymers

New class of photo and electrically switchable azobenzene containing pendant bent‐core liquid crystalline monomers ( AZBM 1, 2 , and 3 ) and their polymers ( AZBP 1, 2 , and 3 ) are reported. The synthesized precursors, monomers, and polymers were characterized by FT‐IR, ¹H, and ¹³C NMR spectroscopy. Thermal stability of polymers was examined by thermogravimetric analysis and revealed stable up to 260 °C. The mesophase transition of monomers and polymers are observed through polarized optical microscopy (POM) and further confirmed by differential scanning calorimetry (DSC). The electrically switching property of monomers and their polymers were studied by electro‐optical method. Among the three monomers AZBM 1, 2 , and 3 , AZBM 1 and 2 exhibit antiferroelectric (AF) switching and AZBM 3 exhibits ferroelectric (F) switching behavior. On the other hand, low molecular weight polymers ( AZMP 1, 2 , and 3 ) show weak AF and F switching behavior. The photo‐switching properties of bent‐core azo polymers are investigated using UV‐vis spectroscopy, trans to cis isomerization occurs around 25 s for AZBP‐1 and 30 s for AZBP‐2 and 3 in chloroform, whereas reverse processes take place around 80 and 90 s. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Three-dimensional profile stitching based on the fiducial markers for microfluidic devices

Profile acquisition of microfluidic devices is a challenging task due to the competing requirements of both large field of view (FOV) and high-resolution. One strategy for obtaining such measurement is linking or stitching high-resolution profiles, possibly from multiple instruments, into a large FOV profile. As opposed to current stitching techniques relying on precise control and measurement of the translation of the sample stage, our approach presented in this paper takes advantage of the overlapping of fiducial markers, to align and stitch the separately measured profiles of a device. This method allows three-dimensional profiles transformed in six degrees of freedom, so that the pitch, roll and yaw among measurements are compensated, and stitching can be processed in both in-plane and out-of plane directions. Measurements of microfluidic channels recorded by an atomic force microscope and a white-light interferometer are stitched with accuracies evaluated to be 0.086 μm and 0.094 μm, respectively. Stitching experiments for large-scale profile gets an accuracy of 0.047 μm. Special form of stitching for profiles acquired by different tools, i.e. key parts of a device profile measured by a small FOV high-resolution instrument are stitched into a large FOV low-resolution profile by another instrument, is also carried out with an accuracy of 0.224 μm.     

Synthesis of β,γ-disubstituted-γ-lactones through a Johnson–Claisen rearrangement: a short route to xylobovide,nor-canadensolide,canadensolide, sporothriolide and santolinolide

The Johnson–Claisen rearrangement of allyl alcohols with chiral vicinal diol functionality was employed to access chiral β,γ-disubstituted-γ-lactones in high enantio- and diastereoselectivity. These were efficiently converted into nor-canadensolide, the advanced γ-(lactone–lactol) intermediate for xylobovide, canadensolide and sporothriolide and the lactone moiety of the santolinolides.     

Electro-disclinic effect in tilted smectic phases of banana-shaped liquid crystal materials

We give the first evidence that the director tilt angle can be reduced by electric fields in the tilted smectic phase of banana-shaped molecules. In these phases the value of polarization is determined by the molecular packing and no electro-clinic effect is expected. Our studies show that high electric fields eventually induce a meta-stable phase with zero director tilt. The tilted phase slowly recovers at low fields. We propose that the field-induced quenching of the layer fluctuations is responsible for the observed effects.     

Development and validation of an RP‐HPLC method for the quantitation of Orteronel (TAK‐700), a CYP17A1 enzyme inhibitor,in rat plasma and its application to a pharmacokinetic study

A novel, simple, specific, sensitive and reproducible high‐performance liquid chromatography assay method has been developed and validated for the estimation of Orteronel in rat plasma. The bioanalytical procedure involves extraction of Orteronel and phenacetin (internal standard) from rat plasma with a simple liquid–liquid extraction process. The chromatographic analysis was performed on a Waters Alliance system using a gradient mobile phase conditions at a flow rate of 1 mL/min and a C₁₈ column maintained at ambient room temperature. The eluate was monitored using a photodiode array detector set at 242. Orteronel and internal standard eluted at 4.8 and 6.2 min, respectively and the total run time was 9 min. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 100–3149 ng/mL (r² = 0.995). The intra‐ and inter‐day precisions were in the ranges of 0.31–7.87 and 3.97–6.35, respectively, in rat plasma. The validated HPLC method was successfully applied to a pharmacokinetic study of Orteronel in rats. Copyright © 2013 John Wiley & Sons, Ltd.     

Characteristics of La-modified Ni-Al2O3 and Ni-SiO2 catalysts for COx-free hydrogen production by catalytic decomposition of methane

Hydrotalcite precursors of La modified Ni-Al₂O₃ and Ni-SiO₂ catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of CO_x-free H₂ by CH₄ decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O₂ pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 °C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al₂O₃ catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 mol_H2 ·mol^?1_Ni. A direct relationship between Ni metal surface area and hydrogen yields was established.     

Charge‐transfer piperazine‐containing polymeric systems via ring‐opening metathesis polymerization

This article describes the synthesis of piperazine‐containing homopolymer systems via ring‐opening metathesis polymerization (ROMP). These systems were subsequently used as electron donors in the formation of charge‐transfer (CT) complexes. Using exo‐N‐(6‐bromohexyl)‐7‐oxabicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxamide as a starting material, monomers were synthesized to act as electron donors. The amine group at the “open” end of the piperazine was either left open or alkylated with various alkyl groups. The monomers' ability to act as electron donors and their polymerization rates were studied. After initial photometric titration studies using 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) as an electron acceptor proved that these monomers would act as electron donors, they were subsequently polymerized into homopolymers via ROMP. The experimental results showed that a methanol:chloroform mixed solvent system enhanced the rate of polymerization over a single solvent (chloroform) system. Studies also showed that the alkylated piperazine‐containing monomer had a faster rate of polymerization than the secondary piperazine monomer. These monomers were used to make piperazine‐containing homopolymers via ROMP and the resulting polymers, like the monomers, also functioned as electron donors. Potential functions of these polymers include electronics, solar cells, optical systems, and biological applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5034–5043, 2009     

Characteristics of La-modified Ni-Al2O3 and Ni-SiO2 catalysts for COx-free hydrogen production by catalytic decomposition of methane

Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 mol 1 Ni. A direct relationship between Ni metal surface area and hydrogen yields was established.     

Approximation by complex Baskakov-Stancu operators in compact disks

In the present paper, we are dealing with the complex Baskakov-Stancu operators and study Voronovskaja type results with quantitative estimates for these operators attached to analytic functions on compact disks. Also, the exact order of approximation is found.