A highly luminescent three-dimensional microporous metal-organic framework, [Zn(2)(oba)(2)(bpy)]·DMA, demonstrates unique selectivity for the detection of high explosives and other aromatics via a fluorescence quenching and enhancement mechanism.
Propane/propene separation by cryogenic distillation is one of the most energy and cost intensive industrial processes. Adsorptive separation is a more energy-efficient alternative. Three isostructural zinc imidazolate zeolitic framework materials are found, for the first time, to be very promising in the separation of propene and propane based on their different diffusion rates. Fine-tuning of the pore opening size is critical for this type of separation.
Sensors and sensitivity: A highly luminescent microporous metal-organic framework, [Zn(2)(bpdc)(2)(bpee)] (bpdc = 4,4'-biphenyldicarboxylate; bpee = 1,2-bipyridylethene), is capable of very fast and reversible detection of the vapors of the nitroaromatic explosive 2,4-dinitrotoluene and the plastic explosive taggant 2,3-dimethyl-2,3-dinitrobutane, through redox fluorescence quenching with unprecedented sensitivity (see spectra).
The design, synthesis, and structural characterization of two microporous metal–organic framework structures, [M(bdc)(ted)0.5]·2 DMF·0.2 H2O (M = Zn (1), Cu (2); H2bdc = 1,4‐benzenedicarboxylic acid; ted = triethylenediamine; DMF: N,N‐dimethylformamide) is reported. The pore characteristics and gas sorption properties of these compounds are investigated at cryogenic temperatures, room temperature, and higher temperatures by experimentally measuring argon, hydrogen, and selected hydrocarbon adsorption/desorption isotherms. These studies show that both compounds are highly porous with a pore volume of 0.65 (1) and 0.52 cm3 g– 1 (2). The amount of the hydrogen uptake, 2.1 wt % (1) and 1.8 wt % (2) at 77 K (1 atm; 1 atm = 101 325 Pa), places them among the group of metal–organic frameworks (MOFs) having the highest H2 sorption capacity. [Zn(bdc)(ted)0.5]·2 DMF·0.2 H2O adsorbs a very large amount of hydrocarbons, including methanol, ethanol, dimethylether (DME), n‐hexane, cyclohexane, and benzene, giving the highest sorption values among all metal–organic based porous materials reported to date. In addition, these materials hold great promise for gas separation.
An important aspect in the research and development of white light-emitting diodes (WLEDs) is the discovery of highly efficient phosphors free of rare-earth (RE) elements. Herein we report the design and synthesis of a new type of RE-free, blue-excitable yellow phosphor, obtained by combining a strongly emissive molecular fluorophore with a bandgap modulating co-ligand, in a three-dimensional metal organic framework. [Zn6(btc)4(tppe)2(DMA)2] (btc = benzene-1,3,5-tricarboxylate, tppe = 1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)ethene, DMA = dimethylacetamide) crystallizes in a new structure type and emits bright yellow light when excited by a blue light source. It possesses the highest internal quantum yield among all RE-free, blue-excitable yellow phosphors reported to date, with a value as high as 90.7% (λex = 400 nm). In addition to its high internal quantum yield, the new yellow phosphor also demonstrates high external quantum yield, luminescent and moisture stability, solution processability, and color tunability, making it a promising material for use in phosphor conversion WLEDs.
A red, semiconducting salt containing TMTSF and T_CNQ crystallizes in the triclinic system, space group P1, with one molecule of each component in a unit cell with the following crystal data: C IoHI2Se4.CI2H4N4, M r = 652.24, a = 8.096(3), b = 10.465(3), c = 6.998 (2)/k, a = 103.78 (2), /3 = 98.49 (3), ~ = 94.91 (3) ° , V = 565.0 (3) A a, D,, = 1.94 (1), D c = 1.92 g cm -3. Intensity data, collected by counter methods on an automated diffractometer operating in the 0-20 scan mode and employing monochromatized Mo Ka radiation (2 = 0.71069/~,, g = 71.2 cm-~), gave 2306 non-zero reflections which were used in the refinement of a standard heavy-atom solution by the full-matrix least-squares method. With fully anisotropic parameters for the nonhydrogen atoms and fixed, isotropic parameters for the H atoms, a final R value of 0.045 was obtained. The structure is composed of stacks of alternating TCNQ and TMTSF molecules positioned about centers of symmetry along the crystallographic c axis and separated by ~3.5 A. Each molecular component is rather planar and the TCNQ molecule is very nearly parallel to and directly centered above and below each adjacent TMTSF molecule and vice versa. The observed stacking pattern yields an excellent approximation to a mixed-stack array whose re-molecular charge-transfer integral is zero. It is estimated from vibrational frequency data and structural considerations that the degree of charge transfer is non-zero and approximately 0.2 e. The non-zero charge transfer is suggested to arise from the admixing of excited-state molecular orbitals within the mixed-stack crystal band.
A high-throughput screen (HTS) of the MLPCN library using a homogenous fluorescence polarization assay identified a small molecule as a first-in-class direct inhibitor of Keap1-Nrf2 protein-protein interaction. The HTS hit has three chiral centers; a combination of flash and chiral chromatographic separation demonstrated that Keap1-binding activity resides predominantly in one stereoisomer (SRS)-5 designated as ML334 (LH601A), which is at least 100× more potent than the other stereoisomers. The stereochemistry of the four cis isomers was assigned using X-ray crystallography and confirmed using stereospecific synthesis. (SRS)-5 is functionally active in both an ARE gene reporter assay and an Nrf2 nuclear translocation assay. The stereospecific nature of binding between (SRS)-5 and Keap1 as well as the preliminary but tractable structure-activity relationships support its use as a lead for our ongoing optimization.
Ein hoch empfindlicher Sensor: Mit dem intensiv lumineszierenden mikroporösen Metall‐organischen Gerüst [Zn2(bpdc)2(bpee)] (bpdc=4,4′‐Biphenyldicarboxylat; bpee=1,2‐Bipyridylethen) lassen sich Dämpfe des Nitrosprengstoffs 2,4‐Dinitrotoluol und von 2,3‐Dimethyl‐2,3‐dinitrobutan, das Plastiksprengstoff als Markierung zugemischt wird, durch Redox‐Fluoreszenzlöschung sehr schnell, reversibel und mit unerreichter Empfindlichkeit nachweisen (siehe Spektren).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.