Good-quality single crystals of the title compound, indigo B [systematic name: 2-(3-oxoindolin-2-ylidene)indolin-3-one], C16H10N2O2, have been prepared with high selectivity by a sublimation process. The previous structure of indigo B [Süsse & Wolf (1980 ▶). Naturwissenschaften, 67, 453], which showed that the complete molecule is generated by crystallographic inversion symmetry has been confirmed, but the present study reports more realistic geometrical parameters and modern standards of precision (e.g. σ for C—C bonds = 0.002–0.003 Å). Each molecule features two intramolecular N—H⋯O hydrogen bonds. In the crystal, molecules are linked by strong face-to-face π–π stacking interactions involving both the six- and five-membered rings [centroid–centroid separations = 3.6290 (14) and 3.6506 (14) Å] and intermolecular N—H⋯O hydrogen bonds.
Large crystals of all-silica, aluminum-, and boron-containing ferrierite zeolites were synthesized using a solvothermal synthesis method and a fluoride medium. Alkylamines, namely, propylamine, butylamine, and pentylamine were employed as templates in the syntheses. The products were characterized by powder X-ray diffraction (XRD), inductively coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), elemental (CHN) analyses, scanning electron microscopy (SEM), N2-adsorption, and 1H, 11B, 27Al, as well as 29Si MAS NMR spectroscopy. The 27Al and 11B MAS NMR spectroscopic investigations revealed that aluminum and boron were successfully incorporated into the FER-type framework. SEM indicated the occurrence of crystals with a size of up to about 600 μm. Furthermore, for all-silica and boron-containing ferrierite zeolites, the shape, size, and thickness of the crystals could be controlled by increasing the chain length of the alkyl group in the alkylamine and the crystallization time. Aluminum-containing ferrierite zeolites could be synthesized with a rectangular morphology exclusively. Observation of transient guest profiles during methanol uptake by means of IR microscopy exemplifies the possibility of directly observing diffusion anisotropy in FER-type frameworks.
A series of isostructural 3D coordination polymers (3)∞[M(tdc)(bpy)] (M(2+) = Zn(2+), Cd(2+), Co(2+), Fe(2+); tdc(2-) = 2,5-thiophenedicarboxylate; bpy = 4,4'-bipyridine) was synthesized and characterized by X-ray diffraction, thermal analysis, and gas adsorption measurements. The materials show high thermal stability up to approximately 400 °C and a solvent induced phase transition. Single crystal X-ray structure determination was successfully performed for all compounds after the phase transition. In the zinc-based coordination polymer, various amounts of a second type of metal ions such as Co(2+) or Fe(2+) could be incorporated. Furthermore, the catalytic behavior of the homo- and heteronuclear 3D coordination polymers in an oxidation model reaction was investigated.
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