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Properties arising from ordered periodic mesostructures are often obscured by small, randomly oriented domains and grain boundaries. Bulk macroscopic single crystals with mesoscale periodicity are needed to establish fundamental structure-property correlations for materials ordered at this length scale (10-100 nm). A solvent-evaporation-induced crystallization method providing access to large (millimeter to centimeter) single-crystal mesostructures, specifically bicontinuous gyroids, in thick films (>100 µm) derived from block copolymers is reported. After in-depth crystallographic characterization of single-crystal block copolymer-preceramic nanocomposite films, the structures are converted into mesoporous ceramic monoliths, with retention of mesoscale crystallinity. When fractured, these monoliths display single-crystal-like cleavage along mesoscale facets. The method can prepare macroscopic bulk single crystals with other block copolymer systems, suggesting that the method is broadly applicable to block copolymer materials assembled by solvent evaporation. It is expected that such bulk single crystals will enable fundamental understanding and control of emergent mesostructure-based properties in block-copolymer-directed metal, semiconductor, and superconductor materials.

The present study describes the use of poly-(ethylene oxide)-block-poly(hexyl methacrylate) diblock copolymers (PEO-b-PHMA) as structure-directing agents for the synthesis of nanostructured polymer-inorganic hybrid materials from (3-glycidylpropyl)trimethoxysilane and aluminium sec-butoxide as precursors and organic, volatile solvents. Four different morphologies, i.e., inorganic spheres, cylinders, lamellae, and organic cylinders in an inorganic matrix, are obtained confirmed by a combinaison of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The composites are further characterized by differential scanning calorimetry (DSC) and solid-state 13 C, 29 Si, and 27 Al NMR. It is demonstrated that the change in the hydrophobic block from polyisoprene (PI) to poly(hexyl methacrylate) (PHMA) has no significant effect on the local structure of the inorganic rich phase. By the dissolution of the composites rich in poly(hexyl methacrylate), nano-particles of different shapes, i.e. spheres, cylinders, and lamellae, are obtained as demonstrated by atomic force microscopy (AFM) and TEM. Finally, calcination of composites with the inverse hexagonal structure at elevated temperatures up to 600°C results in nanostructured aluminosilicates that retain their structure as evidenced through a combination of SAXS and TEM. The study opens pathways towards tailoring fillermatrix interactions in model nanocomposites and builds the bases for the preparation of composites from multiblock copolymers with polyisoprene (PI), poly(ethylene oxide) (PEO), and poly(hexyl methacrylate) (PHMA) as building blocks.

We describe the preparation of amphiphilic diblock copolymers of poly(ethyelene oxide) (PEO) and poly(hexyl methacrylate) (PHMA) synthesized by anionic polymerization of ethylene oxide and subsequent atom transfer radical polymerization (ATRP) of hexyl methacrylate (HMA). The first block, PEO, is prepared by anionic polymerization of ethylene oxide in tetrahydrofuran. End capping is achieved by treatment of living PEO chain ends with 2-bromoisobutyryl bromide to yield a macroinitiator for ATRP. The second block is added by polymerization of HMA, using the PEO macroinitiator in the presence of dibromobis(triphenylphosphine) nickel(II), NiBr 2 (PPh 2 ) 2 , as the catalyst. Kinetics studies reveal absence of termination consistent with controlled polymerization of HMA, GPC data show low polydispersities of the corresponding diblock copolymers. The microdomain structure of selected PEO-block-PHMA block copolymers is investigated by small angle X-ray scattering experiments, revealing behavior expected from known diblock copolymer phase diagrams.

Three commercial styrenic triblock copolymers were subjected to planar extension in a lubricated channel die, as a model for the orientation that may occur during processing operations. Materials that contain cylinders of polystyrene show a pronounced orientation of the cylinder axis in the flow direction, as revealed by small-angle X-ray scattering in the three orthogonal directions. This anisotropy produces small-strain tensile moduli that differ by a factor of 10 or more in the two in-plane directions. A material that contains lamellae of polystyrene shows pronounced orientation of the lamellae in the plane of the sample ; in particular, lamellar normals are strongly forbidden from pointing along the flow direction. For similar strains, planar extension is much more effective in orienting these materials than simple shear.

The Reaction of 2-Aminothiophene-3-carbonitriles with Heterocumulenes. The reaction of 2-aminothiophene-3-carbonitriles (1) with phenyl isothiocyanate does not yield the expected thieno[2,3-d]pyrimidine derivatives but the substituted dithieno-[2′,3′:4, 3][2′,3′:8, 9]pyrimido[3, 4-a]pyrimid-7-thiones (4). The compounds 4 also may be synthesized from 1 and thiophosgene. Analogously, from 1 and phenyl isocyanate the substituted dithieno[2′,3′:4, 3][2′,3′:8, 9]pyrimido[3, 4-a]pyrimid-7-ones (9) arise in small yields. They are better obtainable from 1 and phosgene. Carbon disulphide react with 1 in pyridine to form a mixture of the thieno[2, 3-d]pyrimid-2, 4-dithione (10) and the condensed compound 4. The ratio of products depends on the substituents in the 4, 5-position of 1. The structures are investigated by n.m.r.-spectroscopy.

From 1982 to 1987, 40 children with non-metastatic thoracic neuroblastoma were treated with the same therapeutic regimen. According to TNM staging, there were 11 CS I, 19 CS II, and 10 CS III. All patients underwent surgery; 30 had primary surgical excision; in 10 whose tumors were deemed unresectable, surgery was delayed until after a trial of chemotherapy. Operation was completed by several courses of chemotherapy in case of microscopic residual disease or regional lymph node involvement; radiotherapy was delivered in case of gross residual disease. Using this therapeutic approach, EFS is 92% with a median follow-up of 40 months. Severe complications were rare and sequellae appear to be related to the disease, i.e., neurologic consequences of cord compression.

CLAISEN-Condensations with Selected Dithioesters - Synthesis of Special 3-Methylthio-acrylnitriles. A useful synthetic route to the mono- and diheteroaryl-3-methylthio-acrylnitriles 1 and 2 is demonstrated by the thioanalogous CLAISEN-condensation. In the presence of sodium hydride in tetrahydrofurane or under PTC-conditions heteroaryl dithiocarboxylic esters 3 react with CH-acidic compounds 4 or 9 to form 3-mercapto-acrylnitriles (e. g. 5). Methylation leads to mono- and diheteroaryl-3-methylthioacrylnitriles 1 and 10 (type 2). In the same manner tetrathioterephthalic ester 6 reacts with two equivalents of CH-acidic compounds yielding 8 and 11. By means of spectroscopic methods, especially 1H- and 13C-n.m.r., the structures of the compounds obtained are confirmed.

13C-N.M.R. Spektroscopical Studies on Simply Substituted Flavylium-Salts On a series of differently substituted flavyliumsalts 1-3 their 13C-NMR-chemical shifts and their 1J(13CH) coupling constants were recorded and compared with results received by means of semiempirical PPP calculations and using LFE relationships. Both the experimental and theoretical results exhibit concordantly a characteristic alternate electron distribution along the conjugated π-system of the compounds studies and reveal the distinct influence of donor and acceptor substituents on the electron distribution in both the benzopyrylium and the aryl moiety of the flavylium salts studied.

On the Reaction of Oxalic Amidines with Carbonic Acid Derived Heterocumulenes to Imidazolidine-Derivatives A useful synthetic route to nonsymmetric derivatives of imidazolidine (derivatives of parabanic acid) is demonstrated by the reaction of tetraarylated oxalic amidines 1 with different alkyl- and aryl substituted isothiocyanates 4, isoselenocyanates 31, and carbodiimides 30. Acylisothiocyanates 9 react differently leading to a mixture of three cycloacylation products 12, 13 and 14. Silylated heterocumulenes such as 25 and 26 react with 1 to give 28 and 29 transsilylation. Based on the 13C-n.m.r. spectroscopic investigation of the reaction between 1a and methyl isothiocyanate and phenyl isothiocyanate respectively a mechanism is proposed.

Investigations on Regioselectivity of Wittig-Horner and Reformatsky-Reactions on Selected 3,17-Dioxo Steroids The Reformatsky synthesis and the Wittig-Horner olefination of 3,17-dioxo steroids like androsta-1,4-diene-3,17-dione (ADD) 1 and androst-4-ene-3,17-dione (AD) 2 is described. There are differences in the regioselective introduction of identical substructures with these two methods resulting from different nucleophilicity and stereoelectronical relations of these two reagents. In Reformatsky synthesis the oxo group in 3-position predominantly reacts, whereas in the Wittig-Horner olefination (in the case of 1) the reaction occurs mainly in the 17-position. The structures of all new compounds has been confirmed by spectroscopical data.

Nitrogen-15 and Carbon-13 Chemical Shifts and 13C-1H, 13C-15N and 15N-15N Coupling Constants of Parasubstituted Arene Diazonium Salts Nitrogen-15 and carbon-13 chemical shifts and 13C-1H,13C-15N and 15N-15N coupling constants of 15N-enriched p-substituted arene diazonium salts are reported and within the ΔE-approximation investigated. It is shown that changes of ΔE should be taken into account when considering variation of the nitrogen-15 chemical shifts. The influence of substituent effects was discussed within the DSP (dual substituent parameter)-approach.