Umsetzung von hydrobromiertem 1,4-Polybutadien mit lithiumorganischen Verbindungen

Ohne ZusammenfassungMit 1 Abbildung und 1 Tabelle     

Analysis of tea components by high-performance liquid chromatography and high-performance capillary electrophoresis

Tea is one of the most popular beverages in the world. The number of reports on the analysis of tea components, especially for catechins, has recently been increasing. We review the recent reports on the analysis of tea components using the analytical methods of high-performance liquid chromatography and high-performance capillary electrophoresis.     

An investigation of the structure of butadiene by high resolution infra-red and raman spectroscopy

The rotational Raman spectra of butadiene and butadiene-d₆ are found to consist of discrete lines having small ≈0·4 cm⁻¹) yet almost constant spacings, as would be expected for symmetric or nearly symmetric top molecules. An infra-red absorption band (Type C) of butadiene at 908 cm⁻¹ is observed to have a spacing of about 2·5 cm⁻¹. Both the Raman and infra-red spectra provide evidence for the trans structure of the butadiene molecule. From the rotational constants A″ and ″ the following structural parameters were obtained: C=C---C) = 122·9 ± 0·5° rC---C) = 1·47₆ ± 0·010 Å dy]somewhat shorter than recently determined from electron-diffraction experiments).     

CHEMICALLY MODIFIED PHOTOSYNTHETIC BACTERIAL REACTION CENTERS: CIRCULAR DICHROISM, RAMAN RESONANCE, LOW TEMPERATURE ABSORPTION, FLUORESCENCE AND ODMR SPECTRA AND POLYPEPTIDE COMPOSITION OF BOROHYDRIDE TREATED REACTION CENTERS FROM Rhodobacter sphaeroides R26

Abstract— Reaction centers from Rhodobacter sphaeroides have been modified by treatment with sodium borohydride similar to the original procedure [Ditson et al., Biochim. Biophys. Acta 766 , 623 (1984)], and investigated spectroscopically and by gel electrophoresis.
(1) Low temperature (1.2 K) absorption, fluorescence, absorption- and fluorescence-detected ODMR, and microwave-induced singlet-triplet absorption difference spectra (MIA) suggest that the treatment produces a spectroscopically homogeneous preparation with one of the 'additional' bacteriochlorophylls being removed. The modification does not alter the zero field splitting parameters of the primary donor triplet (^TP870).
(2) From the circular dichroism and Raman resonance spectra in the1500–1800 cm^-1 region, the removed pigment is assigned to Bchl_M, e.g. the "extra" Bchl on the "inactive" M-branch.
(3) A strong coupling among all pigment molecules is deduced from the circular dichroism spectra, because pronounced band-shifts and/or intensity changes occur in the spectral components assigned to all pigments. This is supported by distinct differences among the MIA spectra of untreated and modified reaction centers, as well as by Raman resonance.
(4) The modification is accompanied by partial proteolytic cleavage of the M-subunit. The preparation is thus spectroscopically homogeneous, but biochemically heterogenous.     

The preparation and characterisation of dichloro(1,2,4-trithia-3-azabut-2-ene)gold(III), AuCl2(S3N)

Deprotonation of heptasulphurmonoimide at −78°C using BuLi followed by reaction with HAuCl₄ yields AuCl₂(S₃N), in moderate yield (21%), characterised by IR/Raman and UV/Vis spectroscopies.