Use of cheaper metal than Rh, CHCl3-free Pd catalyst, in 1,2-addition of aromatic aldehydes with arylboronic acids

Pd(OAc)₂-(±)-tol-BINAP-catalyzed arylation reaction of aromatic aldehydes with arylboronic acids in the absence of CHCl₃ is described.     

Structure of molten selenium by X-ray diffraction

X-ray diffraction patterns have been obtained from molten selenium at 250, 350, 450 and 550°C. The height of the peak maxima in the structure factor was much the same and the first peak maximum was considerably lower than the second one. It was also found that the first peak maximum decreases with the increase of temperature, but the second and third peak maxima are relatively temperature insensitive within the observed temperature range. A comparison between the atomic radial distribution function obtained in this work and that calculated from the quasi-crystalline model was made. From these results, we may suggest that the structure of molten selenium consists mainly of eight-atom ring units randomly distributed.     

Spin-dependent sum rule for high-energy neutrino reactions

We present a sum rule which related the inclusive cross section for high-energy neutrino scattering on polarized proton targets to the axial-vector coupling constant. The derivation of the sum rule rests on the equal-time algebra of the time-components of the weak currents. The sum rule also provides a discriminatory test of unified models of weak and electromagnetic interactions based on spontaneously-broken gauge symmetry.     

Electrothermal atomization of calcium and strontium in a molybdenum micro-tube

The excitation and ionization of calcium and strontium in a molybdenum micro-tube atomizer and their use in atomic-absorption spectrometry are described. Increasing hydrogen flow led to complex calcium atomization profiles for absorption measurements, but decreasing hydrogen flow resulted in higher atomic emission. Ionization of calcium and its suppression by potassium were also observed. Strontium was measured effectively by atomic absorption because of the higher sensitivity. Increasing hydrogen flow resulted in a lower atomization temperature and higher absorption for strontium, while decreasing hydrogen flow resulted in higher atomic emission. No interference from 100-fold amounts of magnesium, calcium and sodium was found for atomization of strontium, but 100-fold amounts of aluminium shifted the peak temperature for strontium though with no variation of appearance temperature and peak absorption. A small shift in peak temperature was observed for strontium in the presence of 100-fold amounts of phosphate.     

13C Nuclear magnetic resonance spectra of cyclodextrin monomers,derivatives and their complexes with methyl orange

Low molecular mass fractions of water soluble -, -, and -cyclodextrin epichlorohydrin polymer products (cdx-Ep) were characterized by¹³C nuclear magnetic resonance. The derivatives proved not to be polymers, but substituted cdx having one or two glyceryl groups per one glucose at the C-2, C-3 and C-6 positions. Spectra of analogous hydroxy-propyl -cdx indicate that the degree of substitution is rather higher at the C-6 position. Methyl orange (MO) was included into nine kinds of cdx having different inner diameters and hydrophobic torus heights; -, -, and -cdx monomers, 2, 6-dimethyl and 2, 3, 6-trimethyl -cdx, water soluble -, -, and -cdx-Ep and ethyleneglycol-bis(epoxy-propyl) ether products. The inclusion shifts were compared with each other and with the dioxane-induced solvent shift of MO. TheN, N-dimethyl-aniline side of MO shifted to a higher field site with the increase of the inner diameter in cdx. By substituting cdx with ether groups of different length, the mechanism of inclusion formation remains substantially the same, but by lengthening the hydrophobic cavity, the hydrophobic interaction becomes stronger, as a better resemblance of inclusion shifts and solvent shifts can be observed.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986.