Synthesis of antimalarial yingzhaosu A analogues by the peroxidation of dienes with Co(II)/O2/Et3SiH

Co(II)-catalyzed peroxidation of dienes including (S)-limonene in the presence of molecular oxygen and triethylsilane provided in each case the corresponding 2,3-dioxabicyclo[3.3.1]nonane derivatives via the intramolecular cyclization of the unsaturated peroxy radical intermediates. The product composition was remarkably influenced by the structure of the dienes, the nature of the solvents, and the concentration of the substrates and the catalyst. Some of the yingzhaosu A analogues obtained in this study showed notable antimalarial activities in vitro.     

Solid-phase synthesis of photoaffinity probes: highly efficient incorporation of biotin-tag and cross-linking groups

A benzophenone cross-linking group and a biotin-tag hybrid, resin 1a, attached to our novel resin 2 was readily converted to the photoaffnity probe 20 by condensation with the ligand carboxylic acid 19 and cleavage from the resin without purification.     

Ammonium tungstate modified Li-rich Li<Subscript>1+x</Subscript>Ni<Subscript>0.35</Subscript>Co<Subscript>0.35</Subscript>Mn<Subscript>0.30</Subscript>O<Subscript>2</Subscript> to improve rate capability and productivity of lithium-ion batteries

LiNi_1-x-yCo_xMn_yO₂ (NCM) with excessive lithium is known to exhibit high rate capability and charge–discharge cycling durability. However, the practical usage of NCM is difficult, because the positive electrode slurry is unstable and battery cells swell due to the alkaline residual lithium compound generated on the surface of NCM particles. To reduce the residual lithium compound, ammonium metatungstate (AMT) added to NCM is studied, and the effect is investigated by scanning electron microscopy, aberration-corrected scanning transmission electron microscopy, X-ray diffractometry, synchrotron X-ray diffractometry, and several electrochemical measurements. It is found that the AMT modification reduces the amount of alkaline residual lithium compound and improves the rate capability due to the ~1-nm-thick W-rich layer generated on the NCM surface.

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Nitrogen–Carbon Bond Formation by Reactions of a Titanium–Potassium Dinitrogen Complex with Carbon Dioxide,tert-Butyl Isocyanate,and Phenylallene

Nitrogen–carbon bond-forming reactions at coordinated dinitrogen in a bifunctional titanium–potassium system are reported. A titanium atrane complex with a tris(aryloxide)methyl ligand ( 1 ) was treated with two equivalents of potassium naphthalenide under N₂ atmosphere to generate a bifunctional complex ( 2 ) in which N₂ binds end-on to two titanium centers and side-on to three potassium cations. Dinitrogen complex 2 reacted with carbon dioxide, tert-butyl isocyanate, and phenylallene, forming nitrogen–carbon bonds and affording diverse N-functionalized products. The reaction of 2 with CO₂ followed by addition of Me₃SiCl resulted in the formation of the starting complex 1 with concomitant release of silylated carboxyl hydrazines while the reaction with two equivalents of tert-butyl isocyanate proceeded by insertion into the Ti−N bonds. Treatment of 2 with phenylallene afforded vinyl-substituted hydrazido complexes.     

Multi‐Stimuli‐Responsive Polymeric Materials

Stimuli‐responsive materials are of immense importance because of their ability to undergo alteration of their properties in response to their environment. The properties of such materials can be tuned by subtle adjustments in temperature, pH, light, and so forth. Among such smart materials, multi‐stimuli‐responsive polymeric materials are of pronounced significance as they offer a wide range of applications and their properties can be tuned through several mechanisms. Here, we aim to highlight some recent studies showcasing the multi‐stimuli‐responsive character of these polymers, which are still relatively little known compared to their single‐stimuli‐responsive counterpart.     

Pentacoordinated Carboxylate π‐Allyl Nickel Complexes as Key Intermediates for the Ni‐Catalyzed Direct Amination of Allylic Alcohols

Direct amination of allylic alcohols with primary and secondary amines catalyzed by a system made of [Ni(1,5‐cyclooctadiene)₂] and 1,1′‐bis(diphenylphosphino)ferrocene was effectively enhanced by adding nBu₄NOAc and molecular sieves, affording the corresponding allyl amines in high yield with high monoallylation selectivity for primary amines and high regioselectivity for monosubstituted allylic alcohols. Such remarkable additive effects of nBu₄NOAc were elucidated by isolating and characterizing some nickel complexes, manifesting the key role of a charge neutral pentacoordinated η³‐allyl acetate complex in the present system, in contrast to usual cationic tetracoordinated complexes earlier reported in allylic substitution reactions.     

Three‐Dimensional Nitrogen‐Doped Hierarchical Porous Carbon as an Electrode for High‐Performance Supercapacitors

A facile and sustainable procedure for the synthesis of nitrogen‐doped hierarchical porous carbons with a three‐dimensional interconnected framework (NHPC‐3D) was developed. The strategy, based on a colloidal crystal‐templating method, utilizes nitrogenous dopamine as the precursor due to its unique properties, including self‐polymerization under mild alkaline conditions, coating onto various surfaces, a high carbonization yield, and well‐preserved nitrogen doping after heat treatment. The obtained NHPC‐3D possesses a high surface area of 1056 m² g^?1, a large pore volume of 2.56 cm³ g^?1, and a high nitrogen content of 8.2 wt %. The NHPC‐3D is implemented as the electrode material of a supercapacitor and exhibits a specific capacitance as high as 252 F g^?1 at a current density of 2 A g^?1. The device also shows a high capacitance retention of 75.7 % at a higher current density of 20 A g^?1 in aqueous electrolyte due to a sufficient surface area for charge accommodation, reversible pseudocapacitance, and minimized ion‐transport resistance, as a result of the advantageous interconnected hierarchical porous texture. These results showcase NHPC‐3D as a promising candidate for electrode materials in supercapacitors.     

A 1-hydroxy-2,3,1-benzodiazaborine-containing π-conjugated system: Synthesis,optical properties and solvent-dependent response toward anions

Our interest in the functionalization of OH-substituted azaborines prompted us to synthesize a 1-hydroxy-2,3,1-benzodiazaborine conjugated with 1,8-naphthalimide 1. Its fluorescence was dramatically affected by the nature of the solvent. In particular, the use of DMSO, which has a relatively high donor number (DN = 29.8), led to a remarkable decrease in the fluorescence intensity (Φ_F = 0.0014), possibly due to intermolecular hydrogen-bonding interactions (Me₂SO?HOB). The presence of the hydroxyl group on boron led to a solvent-driven colorimetric response towards anions; high selectivity for F^? over other anions in DMSO, and responded to AcO^? and F^? in THF, as shown by UV/vis titrations, NMR, and mass spectroscopic analysis. The nucleus-independent chemical shift (NICS) indices suggested that hydrogen bonding interactions between Me₂SO and HOB reduced the aromaticity of the benzodiazaborine macrocycle, causing an increase in the negative character of the boron. The increase in the polarity of the BN bond may prevent acetate-binding of 1 in DMSO.     

Well-defined aqueous nanoassemblies from amphiphilic meta-terphenyls and their guest incorporation

Spherical molecular assemblies with diameters of ∼2 nm were quantitatively formed in water from new amphiphilic meta-terphenyls with two hydrophilic pendants at the central benzene ring. Whereas intermolecular interactions between small aromatic rings are typically weak, the obtained nanoassemblies are stable enough at wide-ranging concentrations and mostly remain intact even in the presence of similar nanoassemblies with polyaromatic frameworks. The nanoassembly with pentamethyl-substituted terminal benzene rings provides superior host capability for fluorescent dyes in water.