Definitive evidence for a proximal effect of pyridine in the NaOCl/Mn(porphyrin)x / pyridine catalytic oxygenation system

Using pyridine-attached manganese porphyrins, it has been possible to obtain definitive evidence that pyridine behaves as a proximal ligand in the NaOCl/Mn(porphyrin)X catalytic oxygenation system.     

The role of soft gluons in lepton pair production

We derive expressions for the exponentiation of soft gluon effects in lepton pair production and discuss their phenomenological implications for the rapidity and Q² dependence of the so-called $\text{“K-}\text{factor}\text{”}$. Predictions are given for scaling violations to be seen in the determination of the pion structure function.     

Soliton generation in the forced non-linear Schrödinger equation

We derive a finite-dimensional model which describes the generation of solitons in the forced non-linear Schrödinger equation. Its qualitative behaviour is in good agreement with previous numerical computations.     

Formation of arynezirconocenes from substituted diaryl bis (t-butylcyclopentadienyl) zirconium: application to the synthesis of new functionalized ortho-dichalcogenobenzene compounds

The para-substituted diphenylzirconocenes [(t-BuCp)₂Zr(p-C₆H₄R)₂; R = Br, NMe₂] (A) were easily obtained from the reaction of the appropriate organolithium reagent with bis(t-butylcyclopentadienyl)zirconium dichloride. Elimination of bromobenzene or N,N-dimethylaminobenzene from A by slight heating led to arynezirconocenes into which were inserted two equivalents of elementary chalcogens. As a result dichalcogenated zirconacycles [(t-BuCp)₂ZrY₂C₆H₃R; Y = S, Se] (B) were obtained. Complexes B constitute useful potential synthons in organic synthesis and a large family of new functionalized dichalcogenated benzenic compounds was prepared by reacting electrophiles. The structure of complexes B as well as related benzenic derivatives has been confirmed by microanalysis, ¹H NMR and mass spectrometry.     

Intensities and air broadening coefficients of O3 in the 5- and 3-μm regions

Absolute intensities, self-broadening, and nitrogen and oxygen broadening of O₃ were measured on 22 lines in two different spectral regions: 5 μm corresponding to ν₁ + ν₃ band and 3 μm to ν₁ + ν₂ + ν₃. The results are reported along with their accuracies and compared with theoretical studies.     

Capto-dative substituent effects. 121 - New ketene equivalents for diels-alder cycloadditions

We describe the use of “capto-dative” olefins $\text{1}$ as novel ketene equivalents which behave as efficient dienophiles in the Diels-Alder process.     

L'oxyde double TeVO4 II. Structure cristalline de TeVO4-β-relations structurales

β-TeVO₄ crystallizes in the monoclinic system with the space group $\text{P2}{}_1\text{c}$ and the parameters: a = 4.379 Å, b = 13.502 Å, c = 5.446 Å, and β = 91.72°. Vanadium occupies the center of a square pyramid of oxygens, an extra oxygen is at VO = 2.77 Å. These distorted octahedra share corners forming puckered sheets parallel to (010). The sheets are held together by [Te₂O₆]^4? groups in which tellurium is one-side coordinated by four oxygen atoms.     

Nanocomposites NiFe2O4/SiO2 and CoFe2O4/SiO2-Preparation by Sol-Gel Method and Physical Properties

This paper aims to characterise the systems NiFe₂O₄/SiO₂ and CoFe₂O₄/SiO₂ prepared by the sol-gel method. After heat treatment, the various samples have been studied by means of X-ray diffraction, Mössbauer spectroscopy, magnetic measurements and transmission electron microscopy (HR TEM).X-ray diffraction and Mössbauer spectra confirmed the presence of the spinel phase. HR TEM observations revealed the nanocrystals with the size in the range of 2–25 nm. Magnetic measurements showed a superparamagnetic behaviour of the samples heated at lower temperature (800°C) and ferrimagnetic character for the samples heated at higher temperature (900, 1000°C).The final phase composition of the heated samples depends on the preparation conditions. The samples, treated up to 300°C in vacuum and then subsequently heated at 800°C or 900°C, do not contain hematite (the most stable phase at higher temperatures). On the contrary, the samples heated at 1000°C or 1250°C display certain content of hematite.