Die chromatographische Trennung der fettlöslichen Vitamine im Fliehkraftfeld

Zusammenfassung Die Chromatographie fettlöslicher Vitamine im Fliehkraftfeld wurde beschrieben. Zur Trennung dieser Verbindungen hat sich am besten mit 10- bis 20%iger Paraffinöl-Petroläther-Lösung imprägniertes Whatmanpapier Nr. 3 und als Laufmittel wasserfreies Methanol und wasserfreies Äthanol bewährt. Es empfiehlt sich, die Flecken mittels UV-Licht und 20%iger SbCl₅-Chloroformlösung sichtbar zu machen. Ein großer Vorteil des beschriebenen Verfahrens ist seine Schnelligkeit. Gute Trennung der einzelnen Substanzen wird in maximal 40 Minuten erzielt.

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Summary The chromatography of fat-soluble vitamins in the centrifugal force field is described. Whatman paper No. 3 impregnated with 10- to 20% of paraffin oil-petroleum ether solution has been found best for the separation of these compounds with anhydrous methanol and anhydrous ethanol as carrier agent. It is advisable to render the flecks visible by means of UV-light and 20% SbCl₅-chloroform solution. One of the advantages of the method described here is its rapidity. Good separation of the individual substances is achieved in a maximum of 40 minutes.

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Résumé On décrit la chromatographie de vitamines liposolubles, dans un champ de force centrifuge. Pour la séparation de ces composés, il se confirme que le papier Whatman n° 3 imprégné d'une solution d'éther de pétrole-huile de paraffine à 10–20% représente ce qu'il y a de mieux, avec comme éluant le méthanol anhydre et l'éthanol anhydre. On recommande de révéler les taches par la lumière UV et une solution de SbCl₅ à 20% dans le chloroforme. Un grand avantage du procédé décrit est sa rapidité. On réalise une bonne séparation de chaque substance en 40 minutes au maximum.

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V. Mitt.: J. Chromatography, im Druck.     

Spectroscopic binding studies of novel fluorescent distamycin derivatives

Novel distamycin-porphyrin conjugates were synthesized and their interaction with calf thymus DNA was studied. Minor groove binding of the distamycin part of the molecule was confirmed. The porphyrin part of the conjugates exhibited intercalation and the non-specific electrostatic interaction with the phosphate groups of DNA.     

Optical absorption in PECVD deposited thin hydrogenated silicon in light of ordering effects

We report results obtained from measurements of optical transmittance spectra carried out on a series of silicon thin films deposited by plasma-enhanced chemical vapour deposition (PECVD) from silane diluted with hydrogen. Hydrogen dilution of silane results in an inhomogeneous growth during which the material evolves from amorphous hydrogenated silicon (a-Si:H) to microcrystalline hydrogenated silicon (μc-Si:H). Spectral refractive indices and absorption coefficients were determined from transmittance spectra. The spectral absorption coefficients were used to determine the Tauc optical band gap energy, the B factor of the Tauc plots, E ₀₄ (energy at which the absorption coefficient is equal to 10⁴ cm⁻¹), and the Urbach energy as a function of the hydrogen dilution. The results were correlated with microstructure, namely volume fractions of the amorphous and crystalline phase with voids, and with the grain size.      

FT‐IR,FT‐Raman and DFT calculations of the salicylanilide derivate 4‐chloro‐2‐(4‐bromophenylcarbamoyl)phenyl acetate

FT‐IR and FT‐Raman spectra of 4‐chloro‐2‐(4‐bromophenylcarbamoyl)phenyl acetate were recorded and analyzed. The vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using the Gaussian03 set of quantum chemistry codes. The red shift of the NH stretching wavenumber in the infrared (IR) spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighbouring oxygen atom. The simultaneous IR and Raman activations of the CO stretching mode give the charge transfer interaction through a π‐conjugated path. Optimized geometrical parameters of the title compound are in agreement with similar reported structures. From the optimized structure, it is clear that the hydrogen bonding decreases the double bond character of CO bond and increases the double bond character of the C N bonds. The first hyperpolarizability, predicted infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non‐linear optics. The assignments of the normal modes are done by potential energy distribution (PED) calculations. Copyright © 2009 John Wiley & Sons, Ltd.     

The specific heat of seignettoelectric ceramics

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The specific heat of seignettoelectric ceramics

     

Investigating spectrum of biological activity of 4- and 5-chloro-2-hydroxy-N-[2-(arylamino)-1-alkyl-2-oxoethyl]benzamides

In this study, a series of twenty-two 5-chloro-2-hydroxy-N-[2-(arylamino)-1-alkyl-2-oxoethyl]benzamides and ten 4-chloro-2-hydroxy-N-[2-(arylamino)-1-alkyl-2-oxoethyl]benzamides is described. The compounds were analyzed using RP-HPLC to determine lipophilicity. Primary in vitro screening of the synthesized compounds was performed against mycobacterial, bacterial and fungal strains. They were also evaluated for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The compounds showed biological activity comparable with or higher than the standards isoniazid, fluconazole, penicillin G or ciprofloxacin. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds as well as their structure-activity relationships are discussed.     

Influence of deposition temperature on amorphous structure of PECVD deposited a-Si:H thin films

The effect of deposition temperature on the structural and optical properties of amorphous hydrogenated silicon (a-Si:H) thin films deposited by plasma-enhanced chemical vapour deposition (PECVD) from silane diluted with hydrogen was under study. The series of thin films deposited at the deposition temperatures of 50–200°C were inspected by XRD, Raman spectroscopy and UV Vis spectrophotometry. All samples were found to be amorphous with no presence of the crystalline phase. Ordered silicon hydride regions were proved by XRD. Raman measurement analysis substantiated the results received from XRD showing that with increasing deposition temperature silicon-silicon bond-angle fluctuation decreases. The optical characterization based on transmittance spectra in the visible region presented that the refractive index exhibits upward trend with increasing deposition temperature, which can be caused by the densification of the amorphous network. We found out that the scale factor of the Tauc plot increases with the deposition temperature. This behaviour can be attributed to the increasing ordering of silicon hydride regions. The Tauc band gap energy, the iso-absorption value their difference were not particularly influenced by the deposition temperature. Improvements of the microstructure of the Si amorphous network have been deduced from the analysis.