Top-down patterning of zeolitic imidazolate framework composite thin films by deep X-ray lithography

For the first time a top-down process was used to control the spatial location of Metal-Organic Frameworks on a surface. Deep X-ray lithography was utilised to micropattern a Zeolitic Imidazolate Framework layer on a sol-gel surface, with exposure hardening the sol-gel by inducing crosslinking while leaving the frameworks intact.     

Komplexometrische Bestimmung von Metallkationenverunreinigungen in Reinchemikalien

Zusammenfassung Ein Verfahren zur quantitativen summarischen Bestimmung von Metallionenverunreinigungen in flüssigen Chemikalien (Reinheitsprüfung) durch komplexometrische Titration mit photometrischer Endpunktsanzeige wird beschrieben. Als Indikator dient Eriochromschwarz T; erfaßbar ist zirka 1 g in 20 ml. Durch einfaches Einengen des Ausgangsmaterials lassen sich noch Metallionengehalte von 0,01 ppm mit einer Genauigkeit von einigen Prozent bestimmen.

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Summary A procedure is described for the quantitative summary determination of metal ion impurities in liquid chemicals (purity tests) through complexo-metric titration with photometric endpoint indication. Eriochrome black T serves as indicator. Approximately 1 g can be detected in 20 ml. Metal ion contents as low as 0.01 ppm can still be determined with a precision of several per cent by simple concentration of the starting material.

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Résumé On décrit un procédé de dosage total quantitatif des impuretés à l'état d'ions métalliques dans les produits chimiques liquides (contrôle de la pureté) par titrage complexométrique avec détection du point équivalent par photométrie. On utilise le noir ériochrome T comme indicateur. La limite de dilution est d'environ 1 g/20 ml. On peut encore doser des teneurs en ions métalliques de 0,01 ppm avec une erreur de quelques pour cent simplement en diminuant la quantité initiale de substance.

     

Synthese und NMR-spektroskopische Charakterisierung neuer Adenin- und 6-Thioxopurincarboxamidine

Synthesis and NMR-Spectroscopic Characterization of New Adenine- and 6-Thioxopurinecarboxamidines Adenine (1) or 1H-purine-6(7H)-thione ( 4 ) react with carboximidoyl chlorides 2 to yield the adenine-9-carboxamidines 3 or the 6,7-dihydro-6-thioxo-1H-purine-7-carboxamidines 5 and 6,9-dihydro-6-thioxo-1H-purine-9-carboxamidine 6 a , respectively. The structures of the compounds were determined by ¹H- and ¹³C-NMR spectroscopy.     

Bildung tricyclischer Thietan-Derivate durch intramolekulare(2+2)-Cycloaddition

Formation of Thietane Derivatives via Intramolecular (2+2) Cycloaddition On irradiation, the two 4-vinyl-1,3-thiazole-5(4H)-thiones 1a, b , synthesized from thiobenzoic acid and the corresponding 3-amino-2H-azirines 2a , b , undergo an intramolecular (2+2)-cycloaddition reaction of the C?S and C?C bonds to give the tricyclic thietane derivatives 3a , b .     

Kristallstruktur und Konformation eines linearen Pentapyrrols

The crystal structure of the pentapyrrin1 was determined by X-ray diffraction methodes at two temperatures (298K and 97K). It is the first structure determination of a linear polypyrrole with more than four pyrrole rings. In the crystal, the molecule is located on a crystallographic two-fold axis, which passes through the central pyrrole ring. It assumes a helical overall-conformation, which is stabilized by intramolecular hydrogen bonding. The acidic proton at the nitrogen atom of the central pyrrolic ring is disordered, being observed with half occupancy at two symmetry-equivalent positions off the crystallographic diad. Attempts to remove the disorder by cooling to 97K were unsuccessful, since no indication for a phase transition was detected.

     

Thermal expansion in 3d-metal Prussian Blue Analogs—A survey study

We present a comprehensive study of the structural properties and the thermal expansion behavior of 17 different Prussian Blue Analogs (PBAs) with compositions M^II₃[(M′)^III(CN)₆]₂·nH₂O and M^II₂[Fe^II(CN)₆]·nH₂O, where M^II=Mn, Fe, Co, Ni, Cu and Zn, (M′)^III=Co, Fe and n is the number of water molecules, which range from 5 to 18 for these compounds. The PBAs were synthesized via standard chemical precipitation methods, and temperature-dependent X-ray diffraction studies were performed in the temperature range between −150 °C (123 K) and room-temperature. The vast majority of the studied PBAs were found to crystallize in cubic structures of space groups Fm3?m, F4?3m and Pm3?m. The temperature dependence of the lattice parameters was taken to compute an average coefficient of linear thermal expansion in the studied temperature range. Of the 17 compounds, 9 display negative values for the average coefficient of linear thermal expansion, which can be as large as 39.7×¹0⁻⁶ K⁻¹ for Co₃[Co(CN)₆]₂·12H₂O. All of the M^II₃[Co^III(CN)₆]₂·nH₂O compounds show negative thermal expansion behavior, which correlates with the Irving–Williams series for metal complex stability. The thermal expansion behavior for the PBAs of the M^II₃[Fe^III(CN)₆]₂·nH₂O family are found to switch between positive (for M=Mn, Co, Ni) and negative (M=Cu, Zn) behavior, depending on the choice of the metal cation (M). On the other hand, all of the M^II₂[Fe^II(CN)₆]·nH₂O compounds show positive thermal expansion behavior.     

2-Amino-1-cyan-glutaconsäureamid-1-methylester,ein Dimeres des Cyanessigesters und Cyanacetamid

Synthesis of methyl 3-amino-4-carbomyl-2-cyano-2-butenoate is described and2 a classified as a dimer of methyl cyanoacetate and cyanoacetamide. By ammonolysis of the dimer of methyl cyanoacetate with dimethylamine and anilines, resp. the dimethylamide and anilides, resp. (2 b and3 a–j) are obtained. Condensation with salicylaldehyde to the pyrone derivative4 proves the structure of2 a, ring closure reactions in basic or acidic medium yield the pyridones6 a and7 a,b, coupling with diazonium salts the pyridazines8 a–d. The amides2 and the anilides3 show hindered rotation of the enamino- and the amide-group by hydrogen bonds between the nitrogen functions and the ester carbonyl (Z-form). The G values are reported.