Zeolitic imidazolate framework-71 nanocrystals and a novel SOD-type polymorph: solution mediated phase transformations, phase selection via coordination modulation and a density functional theory derived energy landscape.

We report a rapid additive-free synthesis of nanocrystals (NCs) of RHO-type ZIF-71 () of composition [Zn(dcim)2] (dcim = 4,5-dichloroimidazolate) in 1-propanol as solvent at room temperature. NC- has a size of 30-60 nm and exhibits permanent microporosity with a surface area (SBET = 970 m(2) g(-1)) comparable to that of microcrystalline material. When kept under the mother solution NC- undergoes transformation into a novel SOD-type polymorph (), which in turn converts into known ZIF-72 () with lcs topology.

In situ static and dynamic light scattering and scanning electron microscopy study on the crystallization of the dense zinc imidazolate framework ZIF-zni.

The kinetics and mechanism of crystallization of the dense zinc imidazolate framework with zni topology, from comparatively dilute methanol solutions containing Zn(NO(3))·6H(2)O and imidazole with variation of the zinc-to-imidazole ratio, were followed in situ by time-resolved static and dynamic light scattering. The light scattering data revealed that metastable primary particles of about 100 nm in diameter form rapidly upon mixing the component solutions. After a lag time that is dependent on the imidazole concentration, the primary particles aggregate into secondary particles by a monomer addition mechanism with the primary particles as the monomers.

Fast nucleation and growth of ZIF-8 nanocrystals monitored by time-resolved in situ small-angle and wide-angle X-ray scattering.

Prenucleation clusters: in situ synchrotron X-ray scattering with a one-second time resolution revealed the occurrence of nano-sized clusters during the nucleation and early growth of nanocrystals of a zeolitic imidazolate framework (ZIF). The complex crystallization process exhibits similarities with crystallization processes of zeolites from solution. Hmim= 2-methylimidazole.

Modulated synthesis of Zr-based metal-organic frameworks: from nano to single crystals.

We present an investigation on the influence of benzoic acid, acetic acid, and water on the syntheses of the Zr-based metal-organic frameworks Zr-bdc (UiO-66), Zr-bdc-NH(2) (UiO-66-NH(2)), Zr-bpdc (UiO-67), and Zr-tpdc-NH(2) (UiO-68-NH(2)) (H(2) bdc: terephthalic acid, H(2) bpdc: biphenyl-4,4'-dicarboxylic acid, H(2) tpdc: terphenyl-4,4''-dicarboxylic acid). By varying the amount of benzoic or acetic acid, the synthesis of Zr-bdc can be modulated. With increasing concentration of the modulator, the products change from intergrown to individual crystals, the size of which can be tuned.

Metal-organic framework nanofibers via electrospinning.

A hierarchical system of highly porous nanofibers has been prepared by electrospinning MOF (metal-organic framework) nanoparticles with suitable carrier polymers. Nitrogen adsorption proved the MOF nanoparticles to be fully accessible inside the polymeric fibers.

Zeolitic imidazolate framework membrane with molecular sieving properties by microwave-assisted solvothermal synthesis.

A zeolitic imidazolate framework (ZIF-8) as member of the metal-organic framework family has been crystallized as a thin porous layer on an asymmetric ceramic support. Hydrogen can be selected from other gases by molecular sieving.

Asymmetric 1,3-dipolar cycloaddition with a P-stereogenic dipolarophile: an efficient approach to novel P-stereogenic 1,2-diphosphine systems.

The asymmetric 1,3-dipolar cycloaddition of the P-stereogenic dipolarophile (S(p),S(p))-6 to C,N-diphenylnitrone (7) led to previously unknown P-stereogenic isoxazolinyl diphosphine dioxides (R(p),S(p))-8 in enantio- and diastereomerically pure form; their stereospecific reduction with Ti(OiPr)(4)/PMHS proceeds in high yield with retention of configuration at the phosphorus atoms to give enantio- and diastereomerically pure diphosphines, which are conveniently purified via the corresponding diphosphine-diboranes.

Complete 1H and 13C NMR spectral assignment of N-aralkylsulfonamides, N-sulfonyl-1,2,3,4-tetrahydroisoquinolines and N-sulfonyl-2,3,4,5-tetrahydro-1H-2-benzazepines. Conformational analysis of N-[((3',4'-dichlorophenyl)methyl)sulfonyl]-3-methyl-2,3,4,5-tetrahydro-1H-2-benzazepin.

The complete and unambiguous assignment of the 1H NMR and 13C NMR spectra of 26 N-aralkylsulfonamides, N-sulfonyl-1,2,3,4-tetrahydroisoquinolines and N-sulfonylbenz[c]azepines was performed on the basis of APT, DEPT, homonuclear (gs-COSY) and 1H-detected heteronuclear one-bond (gs-HMQC) and long-range (gs-HMBC) correlation experiments. The methylated 2,3,4,5-tetrahydro-1H-2-benzazepine derivative 26 adopts a chair conformation as determined by 1H-1H coupling analysis and gamma-gauche effects. This is supported by a single-crystal X-ray structure analysis.

Lead hydro sodalite [Pb2(OH)(H2O)3]2[Al3Si3O12]2: synthesis and structure determination by combining X-ray rietveld refinement, 1H MAS NMR FTIR and XANES spectroscopy.

Ion exchange of the sodium hydro sodalites [Na3(H2O)4]2-[Al3Si3O12]2 [Na4(H3O2)]2[Al3Si3O12]2 and [Na4(OH)]2[Al3Si3O12]2 with aqueous Pb(NO3)2 solutions yielded, whichever reactant sodalite phase was used, the same lead hydro sodalite, [Pb2(OH)-(H2O)3]2[Al3Si3O12]2. Thus, in the case of the non-basic reactant [Na3(H2O)4]2-[Al3Si3O12]2 an overexchange occurs with respect to the number of nonframework cationic charges. Rietveld structure refinement of the lead hydro sodalite based on powder X-ray diffraction data (cubic, a = 9.

Benzyltrimethylammonium hydroxide trihydrate containing hydroxide--water layers.

In the title compound, C(10)H(16)N(+) x OH(-) x 3H(2)O, two-dimensional bilayer-like arrays of organic cations and corrugated anionic hydroxide-water layers are stacked alternately along the c axis. All hydroxide and water H atoms are in ordered positions, giving rise to a network of hydrogen bonds [O..

NEt4OH.5H2O containing hydroxide-water layers.

In the title compound, tetraethylammonium hydroxide pentahydrate, C(8)H(20)N(+).OH(-).5H(2)O, layers of approximately hexagonally close-packed NEt(4)(+) cations and anionic layers of hydroxide and water molecules are stacked alternately along the b axis.

[Germacranolides, Guaianolides, and Xanthanolides from the Flowers of Arnica mollis and an X-Ray Structure Analysis of Baileyin Acetate].

The flowers of ARNICA MOLLIS afforded, in addition to baileyin ( 1A), baileyin acetate ( 1B), xanthalongin ( 3), and 2-deacetoxy-11alpha,13-dihydroxanthuminol ( 6), the new 1,5- CIS-guaianolides arnimollin acetate ( 2A) and arnimollin tiglinate ( 2A) and the new xanthanolides 11beta3,13-dihydroxanthalongin ( 4) and 11alpha,13-dihydroxanthalongin ( 5). No traces of helenanolides were discernible. The structures were elucidated mainly by high-field NMR spectroscopy.