An electrochemically synthesized sulfonated polyaniline layer for positive charge carrier injection improvement in conjugated polymer devices

We report the use of sulfonated polyaniline, SPAN, as a positive charge transporting layer in organic electronic devices, demonstrating that it can be used to significantly improve injection into conjugated polymers. The introduction of an intermediate SPAN layer improves device rectification, even when low-work-function anode materials such as tin oxide are used.     

Reagentless system for sulphite determination based on polyaniline

A new reagentless system for sulphite (or sulphur dioxide) determination is reported based on the use of an organic conducting polymer, polyaniline, and its absorbance variation at 550 nm, depending on the sulphite concentration. After chemical polymerisation of aniline a very thin film of polyaniline is obtained. Although the response is not fully reversible, each film can be used for at least 10 measurements for low analyte concentrations (up to 0.5 mg l⁻¹) and five measurements for higher sulphite concentrations. Moreover, the reproducibility, ease of preparation and low cost of the films, permit the use of a new disposable system for each measurement. When the change in absorbance at 550 nm was measured for 210 s (stabilisation time), the system showed a linear response, which ranged from 0.025 to 1.50 mg l⁻¹ of sulphite. A theory with regard to the reaction mechanism between the polyaniline films and sulphite is also proposed. The system was applied to sulphite determination in wine samples and the results were in agreement with those obtained by the Official Method of Analysis (iodometric titration).     

Intermolecular hydroamination and hydroarylation reactions of alkenes in ionic liquids

Intermolecular hydroamination or hydroarylation reactions of norbornene and cyclohexadiene performed with catalytic amounts of Brönsted or Lewis acid in ionic liquids were found to provide higher selectivity and yields than those performed in classical organic solvents. The ionic liquid increases the acidity of the media and stabilizes ionic intermediates through the formation of supramolecular aggregates.     

Convergence estimates for the wavelet-Galerkin method: superconvergence at the node points

In this paper we consider a regular 1-periodic initial value problem and Galerkin approximate solutions in subspaces ν _t spanned by scaled translates of a basic function?. Our goal is to estimate the error when? is in a class of functions which we name . Herer is a regularity parameter andm is related with a property (the Strang and Fix condition) which determines the best order of accuracy in theL ²-norm of approximations from ν _h . Whenm=r, includes all scaling functions corresponding tor-regular multiresolution analyses ofL ²(?). We get the exact node values of the given initial condition as coefficients for the approximate initial data. With this procedure, the coefficients of the resulting Galerkin solution can give a very accurate approximation of the exact solution at the node points, provided that? has many vanishing moments. Since this property is not satisfied in general, we work with another modified basic function?* constructed from the integer translates of?. GlobalL ²-estimates are also obtained.     

On the regiochemistry of the methylphenylcyclopropenone dimer. A reinvestigation

The regiochemistry of the previously reported dimer of methyhlphenylcyclopropenone is corrected through analysis of the long-range ¹H, ¹³C correlated (COLOC) 2D nmr spectrum.