An electrochemical cell coupled with disposable screen-printed electrodes for use in flow injection analysis.

An electrochemical cell coupled with disposable screen-printed electrodes (SPEs) that is specifically designed for use in flow injection analysis (FIA) is described in this study. The cell is made of foldable polyoxymethylene (acetal) thick platelets with the bottom portion consisting of a cavity track to drag the SPEs in position and the top portion having predrilled T-like holes to arrange the Ag/AgCl reference electrode and stainless steel inlet & outlet. An "O ring" is suitably fixed on the top of the working electrode to form a thin-layer space where the electrochemical reaction can take place. Hydrodynamic characterization was validated by using a benchmark hexacyanoferrate redox couple. The results of practical analysis of glucose in human plasma clearly demonstrate the characteristics and applicability of the proposed wall-jet electrochemical cell in FIA.     

Synthesis and evaluation of ketophosph(on)ates as beta-lactamase inhibitors

A series of amidoketophosph(on)ates of general structure PhCH2OCONHCH(R)COCHR'(CH2)n(O)P(O2-)(O)R' (R = H, CH3; R' = H, CH3; n = 0, 1; R' = H, CH3, Et, Ph) have been prepared as a potential source of beta-lactamase inhibitors. The phosphonates (n = 0) were obtained by means of the Arbuzov reaction while most of the phosphates were achieved from reaction of phosph(or/on)ic acids with the appropriate diazoketone PhCH2OCONHCH(R)COCR'N2. The electrophilicity of the carbonyl group in the resulting phosph(on)ates was assessed by the degree of hydration in aqueous solution, determined from NMR spectra. These compounds inhibited typical class C and class D beta-lactamases, particularly the latter group, but showed no activity against class A enzymes. To enhance the carbonyl electrophilicity, an alpha-difluorinated analogue (R = H, CHR' = CF2, n = 0, R' = Et) was also prepared, but no enhanced inhibitory activity was observed. All evidence suggested that these compounds inhibited in the carbonyl form rather than by formation of tetrahedral adducts at the beta-lactamase active site. They show promise as leads to specific class D beta-lactamase inhibitors.     

Michael addition of indoles to electron deficient olefins in water catalysed by potassium bisulfate

The Michael addition of indoles to various electron deficient olefins was performed in water using potassium hydrogen sulphate as catalyst at room temperature.     

Novel carboxylated pyrrole- and carbazole-based monomers. Synthesis and electro-oxidation features

Carboxylated pyrrole (Pyr, a index)- and carbazole (Cbz, b index)-containing monomers 6-7a/b and 9a/b have been readily synthesized from the monobenzyl ester of L-glutamic acid and triamine 2 using Clauson-Kaas and amide coupling reactions. In contrast to Pyr-containing compounds 6-7a, and 9a, the three Cbz-containing monomers 6-7b, and 9b have been found electroactive and were successfully electropolymerized on a Pt electrode resulting in the deposition of corresponding insoluble electroconducting polyCOOH polyCbz-films poly(6-7b) and poly(9b).     

New Rational Solutions for Relativistic Discrete Toda Lattice System

In the present work, we examine the soliton excitations in the relativistic Toda lattice model using the rotational expansion method, where the coupling between the lattice sites is varied. For specific choices of the coupling strength we proceed to analyze the nonlinear wave excitations arising in the model which are found to be dark, singular and periodic solitary wave profiles. These solitary wave profiles are admitted to show possible modulation in its amplitude.     

Synthesis and characterization of immobilized activated carbon doped TiO2 thin films

Immobilized activated carbon doped TiO₂ thin films were prepared by sol–gel dip coating method by using Titanium IV isopropoxide as a precursor. Aim of our work is to synthesize and investigate the structural, surface morphology and optical properties of the synthesized thin film. X-ray diffraction pattern reveals that the crystallinity of the film increases with increase in temperature. Also, the structural parameters such as particle size, microstrain and dislocation density have been calculated. The formation of nanosphere of diameter ranging from 300 nm to 500 nm has been confirmed by Scanning electron microscope. Photocatalytic active large optical band gap at 3.75 eV was found by using UV–visible sspectrum.     

Model synthetic studies toward jiadifenin and majucin type seco-prezizaane natural products via a stereo- and enantioselective approach

A concise stereo- and enantioselective approach to seco-prezizaane sesquiterpenoids, leading to the acquisition of two bicyclic fragments, is delineated.     

2,2′‐Diselenobis(4,4‐diphenylcyclohexa‐2,5‐dienone)

The title compound, C₃₆H₂₆O₂Se₂, displays crystallographic twofold symmetry. The packing involves corrugated linear ribbons mediated through C—H?O and C—H?Se inter­actions. The ribbons are connected through C—H?π inter­actions.     

7‐Phenyl‐1‐oxa‐4‐thiaspiro[4.5]decan‐7‐ol stereoisomers

The stereoisomers of 7‐phenyl‐1‐oxa‐4‐thia­spiro­[4.5]­decan‐7‐ol, C₁₄H₁₈O₂S, have the same stereochemistry at the C atom bearing an OH group, i.e. axial OH and equatorial phenyl groups. However, the acetal S and O atoms are axial and equatorial, respectively, in one isomer and reversed in the second. Furthermore, the crystals of one isomer are composed of hydrogen‐bonded mol­ecules involving the hydroxyl H atom and the O atom of the five‐membered heterocyclic ring, with an O?O distance of 2.962 (3) Å, forming a polymeric chain along the b axis. The asymmetric unit of the other isomer is composed of two mol­ecules, wherein hydroxyl H atoms and the O atoms of the five‐membered heterocyclic rings display intramolecular O—H?O hydrogen bonds with O?O separations of 2.820 (2) and 2.834 (2) Å.     

Synthesis and characterization of 9,9-dialkylfluorene capped benzo[c]thiophene/benzo[c]selenophene analogs as potential OLEDs

The synthesis of soluble benzo[c]thiophene analogs capped with 9,9-dialkylfluorene at one end is described.