Multichannel and low-loss topological photonic crystal fiber in a mid-infrared band.

A multichannel topological photonic crystal fiber (TPCF) with low loss is designed on the basis of two combined different basic photonic crystal units with topologically protected corner states. The relationship between the position modulation parameters and the characteristic frequency of the corner states is studied. Different spatial distributions of the corner states with different transmission wavelengths are found.

Palladium-catalyzed redox diversified entry to axially chiral styrenes asymmetric olefination with alkynes.

Axially chiral olefins represent an underexplored class of atropoisomers given their conformational flexibility and relatively low configurational stability. Atroposelective access to axially chiral olefins formation of a chiral axis is challenging. Reported herein is palladium-catalyzed redox-diversified olefination of aryl halides with two classes of bifunctional alkynes based on rational design of catalytic systems.

Acetylated yeast mannan endowing biomimetic electrospun nanofibers with hydrophobicity and moisturizing property for accelerated cutaneous defects repair.

Mammalian skin is composed of hydrophobic polymers such as proteins, polysaccharide and oily matrices, serving as a crucial barrier to prevent adverse factors from rapidly infiltrating the body while also functioning as a key organ for material exchange. However, open wounds resulting from skin defects can disrupt the internal stability of the body's environment, leading to water loss and delaying the wound healing process. Mannan is believed to synergize with natural moisturizing factors (NMF).

Enantioenriched α-Quaternary α-Amino Amides via Copper-Catalyzed Propargylic Amination.

Catalytic enantioselective propargylic amination represents a valuable method toward the synthesis of functionalized amines. Current methods are mostly restricted to the use of sterically unhindered propargylic esters, thus yielding -α-secondary chiral amines. Reported herein is a copper-catalyzed asymmetric propargylic amination of oxazolidine-2,4-diones, enabling efficient access to enantioenriched α-quaternary amides bearing terminal alkyne and amino groups.

Dual 1,2-Migration-Enabled β-Boryl Amide Synthesis.

A metal-free approach for the synthesis of multisubstituted β-boryl amides is achieved via the couplings of dioxazolones with readily accessible vinyl boronate complexes. The dioxazolones undergo a Curtius-type rearrangement, in situ generating electrophilic isocyanates that subsequently react with vinyl boronate complexes. This mechanistically distinct approach enables the efficient construction of structurally diverse β-boryl amides featuring a borylated quaternary carbon center.

Catalytic asymmetric intermolecular [4 + 2] annulation of benzocyclobutenones with Alkynes and activated carbonyls via C-C activation.

The activation of C-C bonds enables rapid construction of new organic frameworks owing to facile structural reorganization. Nevertheless, enantioselective C-C activation remains heavily underexplored and has been predominantly limited to intramolecular reactions. We herein report two categories of asymmetric intermolecular [4 + 2] annulations between benzocyclobutenones (BCBs) and unsaturated reagents, namely, alkynes and cyclic dicarbonyl compounds.

Rhodium(III)-catalyzed oxidative [3+2] annulation of arylboron reagents and 7-azabenzonorbornadienes transmetalation-initiated C-H activation.

Rh(III)-catalyzed oxidative [3+2] annulation between arylboron reagents and azabicyclic olefins is presented. This system offers an effective example of transmetalation-promoted C-H activation using easily available arylboron reagents, which provides a series of -fused dihydrocarbazoles both and functionalization of the arylboron reagents. Importantly, this annulation reaction circumvents the reliance on a directing group in the arene ring.

Extract-Loaded Hybrid Nanostructured Scaffolds Incorporating a Temperature-Sensitive Polymer for Mechanically Assisted Wound Healing.

: (commonly known as thistle) is a traditional Chinese medicinal plant with significant therapeutic potential, exhibiting hemostatic, antioxidant, and wound-healing properties. Electrospinning offers a versatile platform for fabricating nanoscale scaffolds with tunable functionality, making them ideal for drug delivery and tissue engineering. : In this study, a bioactive extract from thistle was obtained and incorporated into a thermosensitive triblock copolymer (PNNS) and polycaprolactone (PCL) to develop a multifunctional nanofibrous scaffold for enhanced wound healing.

Asymmetric Vicinal and Remote Hydroamination of Olefins by Employing a Heck-Reaction-Derived Hydride Source.

Metal hydrides are reactive intermediates in numerous catalytic processes. In many catalytic processes, metal hydrides are formed, but their potential reactivity is often wasted by reaction with a base or an oxidant to permit catalyst turnover. In this report, the hydroamination of unactivated olefins is described by coupling a Heck reaction with a hydroamination reaction between aryl boronic acid, olefin, and a nitrene precursor dioxazolone.

Insight into the impact of pre-cooking and freezing on the colour stability of pakchoi during thermal processing: A study on chlorophyll and organic acid changes.

This study investigated the effects of pre-cooking and freezing on the colour stability, changes of chlorophylls and organic acids during re-cooking and 4-h heating of pakchoi. Pre-cooked and stored pakchoi exhibited yellowish-brown discolouration upon cooking, especially in the stalks, with green values (-a) 42.53 %, 34.

Harnessing pea proteins for thermo-reversible gels: Novel strategy and molecular principle.

Thermo-reversible gels (such as gelatin) have a wide range of applications in the food and pharmaceutical fields. This work reports a thermo-reversible gel prepared with pea protein isolate fractionated using ionic strength-shifting method (I: 0.5 → 0.

Rhodium-Catalyzed Asymmetric Access to P-Chiral Triarylphosphine Oxides via Insertion of P─H Bonds into Diazonaphthoquinones.

While significant progress has been made in the enantioselective insertion of carbenes into heteroatom-hydrogen bonds, this chemistry is restricted to the construction of carbon-based chirality. The asymmetric insertion of carbenes into P─H that delivers P-chiral products remains untouched. Rhodium(I)-catalyzed enantioselective synthesis of P-chiral triarylphosphine oxides via asymmetric C─P coupling of a secondary phosphine oxide (SPO) with diazonaphthoquinone is herein reported.

Bifunctional modified bacterial cellulose-based hydrogel through sequence-dependent crosslinking towards enhanced antibacterial and cutaneous wound healing.

Chronic wounds caused by microbial infection have emerged as a major challenge on patients and medical health system. Bacterial cellulose (BC) characterized by its excellent biocompatibility and porous network, holds promise for addressing complex wound issues. However, lack of inherent antibacterial activity and cross-linking sites in the molecular network of BC have constrained its efficacy in hydrogel design and treatment of bacterial-infected wounds.

Enzymatically deamidated pork myofibrillar protein can form thermo-reversible gels.

By using protein-glutaminase (PG) deamidation, thermo-reversible gel of pork myofibrillar protein (PMP) can be prepared. This study aims to reveal the connection between PMP thermo-reversible gel and the coiled-coil. The research explores how the water-holding capacity and reversibility of these gels improve with increased deamidation time.

Rhodium-catalyzed atropodivergent hydroamination of alkynes by leveraging two potential enantiodetermining steps.

A pair of enantiomers is known to have different biological activities. Two catalysts with opposite chirality are nearly always required to deliver both enantiomeric products. In this work, chiral rhodium(III) cyclopentadienyl complexes are repurposed as efficient catalysts for enantiodivergent and atroposelective hydroamination of sterically hindered alkynes.

-Difluorobicyclo[2.1.1]hexanes via Photochemical [2π + 2σ] Cycloaddition Initiated by Oxidative Activation of -Difluorodienes.

The incorporation of fluorine atoms into three-dimensional sp-rich scaffolds represents an attractive tactic during bioisosteric evolution campaigns by endowing bioisosteric candidates with improved pharmacokinetic properties. Photo- or Lewis acid-mediated bicyclo[1.1.

Ultrafast Room-Temperature Synthesis of Phosphate-Intercalated NiFe Layered Double Hydroxides for High-Performance Alkaline Seawater Oxidation.

Quick and easy synthetic methods and highly efficient catalytic performance are equally important to anodic oxygen evolution reaction (OER) electrocatalysts for alkaline seawater electrolysis. Herein, we report a facile one-step route to in situ growing PO intercalated NiFe layered double hydroxides (NiFe-LDH) on Ni foam (denoted as NiFe-P/NF) by a room-temperature immersion for several minutes. This ultrafast approach transforms the NF surface into a rough PO intercalated NiFe-LDH overlayer, which demonstrates outstanding OER performance in both alkaline simulated and natural seawaters owing to good hydrophilic interface and the electrostatic repulsion of PO against Cl anions.

Ni-catalyzed enantioselective three-component reductive alkylacylation of alkenes: modular access to structurally complex α-amino ketones.

Chiral alpha-amino ketones have found extensive applications as functional molecules. A nickel-catalyzed, enantioselective, and fully intermolecular three-component 1,2-alkylacylation of -acyl enamides has been realized with tertiary alkyl bromides and carboxylic acid-derived electrophiles as the coupling reagents. This reductive coupling strategy is operationally simple, exhibiting broad substrate scope and excellent functional group tolerance using readily available starting materials and allowing rapid access to structurally complex α-amino ketone derivatives in high enantioselectivity.

Access to distal biaxial atropisomers by iridium catalyzed asymmetric C-H alkylation.

Distal biaxial atropisomers are typical structures in chiral catalysts and ligands and offer a wide variety of applications in biology and materials technology, but the development of efficient synthesis of these valuable scaffolds is still in great demand. Herein, we describe a highly efficient iridium catalyzed asymmetric C-H alkylation reaction that provides a range of new distal biaxial atropisomers with excellent yields (up to 99%) and stereoselectivity (up to 99% ee and essentially one isomer). Based on this unprecedented strategy, a polycyclic skeleton with five successive chiral centers as well as C-C and C-N (or N-N) two distal chiral axes was created successfully in mild circumstances.

Rhodium(III)-Catalyzed Oxidative Cross-Coupling of -Pyrimidylindoles with Cyclic β-Keto Esters for Accessing All-Carbon Quaternary Centers.

Rh(III)-catalyzed direct oxidative C-H/C-H cross-coupling between -pyrimidylindoles and β-ketoesters is presented. Easily available β-ketoesters are used as an alkylating agent for the facile construction of all-carbon quaternary centers under mild conditions. The ester group in the product can undergo decarboxylation or decarboxylative amination.

Intermolecular Buchwald-Hartwig Reactions for Enantioselective Synthesis of Diverse Atropisomers: Rerouting the C-N Forming Mechanism to Substrate Oxygen-Assisted Reductive Elimination.

Axially chiral biaryls featuring a C-N axis are important functional molecules in diverse fields. The asymmetric Buchwald-Hartwig reaction represents a powerful strategy for these targets. Previous studies, however, have been predominantly restricted to intramolecular atroposelective coupling, likely due to the steric and entropic effects in the reductive elimination of Pd(II) species with sterically congested aryl and nitrogen groups.

Pd-catalyzed asymmetric Larock reaction for the atroposelective synthesis of N─N chiral indoles.

Atropisomeric indoles defined by a N─N axis are an important class of heterocycles in synthetic and medicinal chemistry and material sciences. However, they remain heavily underexplored due to limited synthetic methods and challenging stereocontrol over the short N─N bonds. Here, we report highly atroposelective access to N─N axially chiral indoles via the asymmetric Larock reaction.

Boron modification promoting electrochemical surface reconstruction of NiFe-LDH for efficient and stable freshwater/seawater oxidation catalysis.

Transition metal-based electrocatalysts generally take place surface reconstruction in alkaline conditions, but little is known about how to improve the reconstruction to a highly active oxyhydroxide surface for an efficient and stable oxygen evolution reaction (OER). Herein, we develop a strategy to accelerate surface reconstruction by combining boron modification and cyclic voltammetry (CV) activation. Density functional theory calculations and in-situ/ex-situ characterizations indicate that both B-doping and electrochemical activation can reduce the energy barrier and contribute to the surface evolution into highly active oxyhydroxides.

Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides C-H activation and formal phosphoryl migration.

A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity.