1,2,4,5‐Tetrakis(diazidomethyl)benzene

The molecule of the title compound, C₁₀H₆N₂₄, lies on a crystallographic inversion centre located in the middle of the benzene ring. Steric overcrowding by the bulky N₃ groups is avoided by the tendency of four azide entities to be arranged parallel to the benzene ring and the other four azide groups to be arranged alternately above and below the benzene plane in a skeletal C_i symmetry. The compound is of interest for high‐energy research and as a precursor for the synthesis of carbon nanotubes, nanospheres or high‐nitrogen carbon nitrides with great potential for biological and technological applications.     

Selective reduction of 1,2-double bond in delta-1,4-3-oxo-steroids

A new method for the selective reduction of the 1,2-double bond in Δ^1,4-3-oxo-steroids is described.     

Monothiohydrochinonäther als Vermittler einer oxydativen Synthese von Adenosin-di- und-triphosphat (ADP undATP)

Zusammenfassung Durch Oxydation von S-Methylmonothio-durohydrochinon (1) oder S-Methylmonothio-2,3-dimethyl-1,4-naphthohydrochinon (2) mit Brom in wasserfr. Pyridin entstehen aus den Tetrabutyl-ammoniumsalzen der Phosphorsäure und des Adenosinmonophosphats: Adenosindiphosphat (ADP) und Adenosintriphosphat (ATP), aus Phosphat und Adenosindiphosphat: etwa 25%ATP.

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By oxidation with bromine of S-methylmonothio-durohydroquinone (1) or of S-methylmonothio-2,3-dimethyl-1,4-naphthohydroquinone (2) in dry pyridine in presence of tetrabutyl-ammonium salts of inorganic phosphate and of adenosine-monophosphate, adenosine-diphosphate (ADP) and adenosine-triphosphate (ATP) are formed. Inorganic phosphate andADP give 25%ATP under the same conditions.

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Fritz Wessely mit freundschaftlichem Gruß zum 70. Geburtstag gewidmet.     

AKD-Modification of bacterial cellulose aerogels in supercritical CO2

Different approaches towards hydrophobic modification of bacterial cellulose aerogels with the alkyl ketene dimer (AKD) reagent are presented. If AKD modification was performed in supercritical CO₂, an unexpectedly high degree of loading was observed. About 15 % of the AKD was bound covalently to the cellulose matrix, while the other part consisted of re-extractable AKD-carbonate oligomers, which are novel chemical structures described for the first time. These oligomers contain up to six AKD and CO₂ moieties linked by enolcarbonate structures. The humidity uptake from environments with different relative humidity by samples equipped with up to 30 % AKD is strongly reduced, as expected due to the hydrophobization effect. Samples above 30 % AKD, and especially at very high loading between 100 and 250 %, showed the peculiar effect of increased humidity uptake which even exceeded the value of unmodified bacterial cellulose aerogels.     

Nonlinear pressure dependence of the interaction potential of dense protein solutions

The influence of pressure on the structure and protein-protein interaction potential of dense protein solutions was studied and analyzed using small-angle x-ray scattering in combination with a liquid state theoretical approach. The structural as well as the interaction parameters of dense lysozyme solutions are affected by pressure in a nonlinear way. The structural properties of water lead to a modification of the protein-protein interactions below 4?kbar, which might have significant consequences for the stability of proteins in extreme natural environments.     

Intercalation in layered metal-organic frameworks: reversible inclusion of an extended π-system

We report the synthesis of layered [Zn(2)(bdc)(2)(H(2)O)(2)] and [Cu(2)(bdc)(2)(H(2)O)(2)] (bdc = benzdicarboxylate) metal-organic frameworks (MOF) carried out using the liquid-phase epitaxy approach employing self-assembled monolayer (SAM) modified Au-substrates. We obtain Cu and Zn MOF-2 structures, which have not yet been obtained using conventional, solvothermal synthesis methods. The 2D Cu(2+) dimer paddle wheel planes characteristic for the MOF are found to be strictly planar, with the planes oriented perpendicular to the substrate. Intercalation of an organic dye, DXP, leads to a reversible tilting of the planes, demonstrating the huge potential of these surface-anchored MOFs for the intercalation of large, planar molecules.