View source for Inferring Lvy hikes through bent trajectories The rescaling method

Hollow layered double hydroxide (LDH) nanostructures derived from metal-organic framework (MOF) nanoparticles (NPs) are candidate materials for applications in catalysis and energy storage. MOF NPs serve as a sacrificial template and are converted into LDH nanomaterials through two simultaneous processes etching of the NPs and growth of LDHs on the NP surfaces. However, for these conversion processes, early reaction stages, intermediate products, and details of their reaction kinetics are still unknown. Using liquid-phase transmission electron microscopy (TEM), we show that cubic and rhombic dodecahedron (RD) ZIF-8 NPs convert into hollow LDH nanocages via the nucleation and growth of LDH nanosheets on their surface as the MOF NPs gradually etch. These direct in situ observations reveal that, in these reactions, maintaining comparable etching and growth rates is key to forming well-defined hollow nanostructures that retain the shape of the underlying MOF NP template. Our study provides a critical insight pivotal to the design and synthesis of complex MOF-derived hollow nanomaterials.A high content of potentially allergenic lectin in Phaseolus vulgaris L. beans is of increasing health concerns; however, understanding of the protein allergenicity mechanism on the molecular basis is scarce. In the present study, low-pH treatments were applied to modify black turtle bean lectin allergen, and a sensitization procedure was performed using the BALB/c mice for the allergenicity evaluation, while the conformational changes were monitored by the spectral analyses and the details were explored by the molecular dynamics simulation. Much milder anaphylactic responses were observed in BALB/c mice experiments. At the molecular level, the protein was unfolded in low acidic environments because of protonation, and α-helix was reduced with the exposure of trypsin cleavage sites, especially the improvement of protease accessibility for Lys121, 134, and 157 in the B cell epitope structural alterations. These results indicate that a low-pH treatment might be an efficient method to improve the safety of legume protein consumption.Zeolite crystals offering a short diffusion pathway through the pore network are highly desired for a number of catalytic and molecule separation applications. Herein, we develop a simple synthetic strategy toward reducing the thickness along the b-axis of MFI-type crystals, thus providing a short diffusion path along the straight channel. Our approach combines preliminary aging and a fluoride-assisted low-temperature crystallization. The synthesized MFI crystals are in the micrometer-size range along the a- and c-axis, while the thickness along the b-axis is a few tens of nanometers. The synthesis parameters controlling the formation of platelike zeolite are studied, and the factors controlling the zeolite growth are identified. The synthesis strategy works equally well with all-silica MFI (silicalite-1) and its Al- and Ga-containing derivatives. The catalytic activity of platelike ZSM-5 in the methanol-to-hydrocarbons (MTH) reaction is compared with a commercial nanosized ZSM-5 sample, as the platelike ZSM-5 exhibits a substantially extended lifetime. The synthesis of platelike MFI crystals is successfully scaled up to a kilogram scale.Many enzymes utilize interactions extending beyond the primary coordination sphere to enhance catalyst activity and/or selectivity. Such interactions could improve the efficacy of synthetic catalyst systems, but the supramolecular assemblies employed by biology to incorporate second sphere interactions are challenging to replicate in synthetic catalysts. Herein, a strategy is reported for efficiently manipulating outer-sphere influence on catalyst reactivity by modulating host-guest interactions between a noncovalently encapsulated transition-metal-based catalyst guest and a metal-organic framework (MOF) host. This composite consists of a ruthenium PNP pincer complex encapsulated in the MOF UiO-66 that is used in tandem with the zirconium oxide nodes of UiO-66 and a ruthenium PNN pincer complex to hydrogenate carbon dioxide to methanol. Due to the method used to incorporate the complexes in UiO-66, structure-activity relationships could be efficiently determined using a variety of functionalized UiO-66-X hoston was readily recyclable, leading to a cumulative TON of 100 000 after 10 reaction cycles.Bis(formazanate)iron(II) complexes undergo a thermally induced S = 0 to S = 2 spin transition in solution. Here we present a study of how steric effects and π-stacking interactions between the triarylformazanate ligands affect the spin-crossover behavior, in addition to electronic substituent effects. Moreover, the effect of increasing the denticity of the formazanate ligands is explored by including additional OMe donors in the ligand (7). [https://www.selleckchem.com/products/dyngo-4a.html Dyngo-4a chemical structure] In total, six new compounds (2-7) have been synthesized and characterized, both in solution and in the solid state, via spectroscopic, magnetic, and structural analyses. The series spans a broad range of spin-crossover temperatures (T1/2) for the LS ⇌ HS equilibrium in solution, with the exception of compound 6 which remains high-spin (S = 2) down to 210 K. In the solid state, 6 was shown to exist in two distinct forms a tetrahedral high-spin complex (6a, S = 2) and a rare square-planar structure with an intermediate-spin state (6b, S = 1). SQUID measurements, 57Fe Mössbauer spectroscopy, and differential scanning calorimetry indicate that in the solid state the square-planar form 6b undergoes an incomplete spin-change-coupled isomerization to tetrahedral 6a. The complex that contains additional OMe donors (7) results in a six-coordinate (NNO)2Fe coordination geometry, which shifts the spin-crossover to significantly higher temperatures (T1/2 = 444 K). The available experimental and computational data for 7 suggest that the Fe···OMe interaction is retained upon spin-crossover. Despite the difference in coordination environment, the weak OMe donors do not significantly alter the electronic structure or ligand-field splitting, and the occurrence of spin-crossover (similar to the compounds lacking the OMe groups) originates from a large degree of metal-ligand π-covalency.