Electrochemical sensors based on platinized Ti1 − x Ru x O2

Electrocatalysts based on platinized titania modified with ruthenia (0–9 mol %) were studied. The synthesized materials were investigated as working electrodes in potentiometric sensors sensitive to hydrogen and carbon monoxide. All electrocatalysts showed reproducible behavior at pure gas concentrations from 400 to 4000 ppm. In CO-H₂ mixtures with comparable concentrations of both gases, the sensors were selective toward hydrogen at ≥0.05 mol % Ru, but not selective to hydrogen or CO at less than 0.05 mol % Ru in the substrate.     

Synthesis of -5,6 Dihydro-1,4,2 Dioxazines from Hydroximates

Successive action of α-bromoesters and organometallics on hydroximates constitute a good way to obtain - 5,6 dihydro-1,4,2 dioxazines.     

An Expedient Method for the Umpolung Coupling of Enols with Heteronucleophiles**

In this paper, we present an unprecedented and general umpolung protocol that allows the functionalization of silyl enol ethers and of 1,3-dicarbonyl compounds with a large range of heteroatom nucleophiles, including carboxylic acids, alcohols, primary and secondary amines, azide, thiols, and also anionic carbamates derived from CO₂. The scope of the reaction also extends to carbon-based nucleophiles. The reaction relies on the use of 1-bromo-3,3-dimethyl-1,3-dihydro-1λ³[d][1,2]iodaoxole, which provides a key α-brominated carbonyl intermediate. The reaction mechanism has been studied experimentally and by DFT, and we propose formation of an unusual enolonium intermediate with a halogen-bonded bromide.     

Accurate control of a liquid-crystal display to produce a homogenized Fourier transform for holographic memories

We show an accurate procedure to obtain a Fourier transform (FT) with no dc term using a commercial twisted-nematic liquid-crystal display. We focus on the application to holographic storage of binary data pages, where a drastic decrease of the dc term in the FT is highly desirable. Two different codification schemes are considered: binary pi radians phase modulation and hybrid ternary modulation. Any deviation in the values of the amplitude and phase shift generates the appearance of a strong dc term. Experimental results confirm that the calculated configurations provide a FT with no dc term, thus showing the effectiveness of the proposal.     

Influence of temperature and time of isothermal holding on the viscosity and crystallization processes of Al-Y melts close to a eutectic structure

We investigate the temperature and time dependences of viscosity of Al₉₉Y₁, Al₉₇Y₃, Al₉₅Y₅ melts in the range from liquidus to 1200°C. By metallographic, XRD, and differential thermal analyses, we study how the time of isothermal holding of melts influences the structure of ingots during hardening.     

Reaction of N-sulfinyltrifluoromethanesulfonamide with triphenylphosphine and triphenylphosphine oxide

The reaction of N-sulfinyltrifluoromethanesulfonamide with triphenylphosphine and triphenylphosphine oxide or of trifluoromethanesulfonamide with dichloro(triphenyl)phosphorane leads to trifluoro-N-(triphenyl-λ⁵-phosphanylidene)methanesulfonamide, which is hydrolyzed to trifluoromethanesulfonamide and triphenylphosphine oxide via the intermediate trifluoro-N-[hydroxy(triphenyl)phosphoranyl]methanesulfonamide.     

Kontsevich and Takhtajan Construction of Star Product on the Poisson–Lie Group GL(2)

Comparing the star product defined by Takhtajan on the Poisson–Lie group GL(2) and any star product calculated from the Kontsevich's graphs (any K-star product) on the same group, we show, by direct computation, that the Takhtajan star product on GL(2) can't be written as a K-star product.     

Thermal, pressure and light switchable spin-crossover materials

This article reviews the most relevant chemical and structural aspects that influence the spin-crossover phenomenon (SCO). Special attention is focussed on the recent development of SCO coordination polymers. The different approaches currently being explored in order to achieve multifunctionality in SCO materials are discussed.