Synergistic effect of P-dopant and N-doped carbon encapsulation on ball-milled silicon nanoparticles improved Li⁺ diffusivity in silicon anode by tenfold. While N-doped carbon encapsulation mainly improves Li⁺ diffusivity, P-dopant increases the internal conductivity and further enhances Li⁺ diffusivity, stabilizing the cell performance at high current densities. The anode achieves 87.32 % capacity retention after 400 cycles at 4000 mA g⁻¹.

Abstract

The silicon (Si) offers enormous theoretical capacity as a lithium-ion battery (LIB) anode. However, the low charge mobility in Si particles hinders its application for high current loading. In this study, ball-milled phosphorus-doped Si nanoparticles encapsulated with nitrogen-doped carbon (P−Si@N−C) are employed as an anode for LIBs. P-doped Si nanoparticles are first obtained via ball-milling and calcination of Si with phosphoric acid. N-doped carbon encapsulation is then introduced via carbonization of the surfactant-assisted polymerization of pyrrole monomer on P-doped Si. While P dopant is required to support the stability at high current density, the encapsulation of Si particles with N-doped carbon is influential in enhancing the overall Li⁺ diffusivity of the Si anode. The combined approaches improve the anode's Li⁺ diffusivity up to tenfold compared to the untreated anode. It leads to exceptional anode stability at a high current, retaining 87 % of its initial capacity under a large current rate of 4000 mA g⁻¹. The full-cell comprising P−Si@N−C anode and LiFePO₄ cathode demonstrates 94 % capacity retention of its initial capacity after 100 cycles at 1 C. This study explores the effective strategies to improve Li⁺ diffusivity for high-rate Si-based anode.

Computational characterisation of transition states for several π-spacers adopted in self-immolative elimination reactions allows rationalising electronic effects on reaction rates, paving the way towards the in silico design of new spacers.

Abstract

The controlled release of chemicals, especially in drug delivery, is crucial, often employing “self–immolative” spacers to enhance reliability. These spacers separate the payload from the protecting group, ensuring a more controlled release. Over the years, design rules have been proposed to improve the elimination process's reaction rate by modifying spacers with electron–donating groups or reducing their aromaticity. The spacer design is critical for determining the range of functional groups released during this process. This study explores various strategies from the literature aimed at improving release rates, focusing on the electronic nature of the spacer, its aromaticity, the electronic nature of its substituents, and the leaving groups involved in the elimination reaction. Through computational analysis, I investigate activation free energies by identifying transition states for model reactions. My calculations align qualitatively with experimental results, demonstrating the feasibility and reliability of computationally pre–screening model self–immolative eliminations. This approach allows proposing optimal combinations of spacer and leaving group for achieving the highest possible release rate.

The article explores the efficacy of a Pd/C@MOF-303-based electrode in improving hydrogen evolution reaction performance within an electrochemical cell. It explores the mechanism underlying this improvement.

Abstract

In this study, we employed a rapid and efficient microwave method to synthesize Metal-Organic Framework (MOF-303), which was subsequently embedded onto Palladium/Carbon (Pd/C) electrodes. The resulting hybrid material, Pd/C@MOF-303, was thoroughly characterized, and its performance in the Hydrogen Evolution Reaction (HER) was systematically investigated. The Pd/C@MOF-303 composite exhibited remarkable improvements in HER performance compared to the unmodified Pd/C electrode. At a benchmark current density of 10 mA cm⁻², the overpotentials for Pd/C and Pd/C@MOF-303 were measured at 185 mV and 175 mV, respectively. This reduction in overpotential highlights the superior catalytic activity of the Pd/C@MOF-303 hybrid material in facilitating the HER. Furthermore, the Pd/C@MOF-303 electrode demonstrated enhanced HER activity, increased mass activity, and excellent charge transfer rates compared to its unmodified counterpart, Pd/C. The findings underscore the significance of the hydrophilic MOF-303 in tailoring the surface characteristics of electrocatalysts, thereby offering insights into the design principles for advanced materials with superior performance in electrochemical applications.

Wet-chemical synthesis refers to the bottom-up chemical synthesis in solution, which is among the most popular synthetic approaches towards functional two-dimensional (2D) materials. It offers several advantages including cost-effectiveness, high yields, and precious control over the production process. As an emerging family of 2D materials, elemental 2D materials (Xenes) have shown great potential in various applications such as electronics, catalysts, biochemistry, and sensing technologies due to their exceptional/exotic properties such as large surface area, tunable band gap, and high carrier mobility. In this review, we provide a comprehensive overview of the current state-of-the-art in wet-chemical synthesis of Xenes including tellurene, bismuthene, antimonene, phosphorene, and arsenene. The current solvent compositions and process parameters utilized in wet-chemical synthesis and their effects on the thickness and stability of the resulting Xenes are also presented. Key factors considered involves ligands, precursors, surfactants, reaction time, and temperature. Finally, we highlight recent advances and existing challenges in the current application of wet-chemical synthesis for Xenes production and provide perspectives on future improvement.

This review summarizes recent progress in the development of stimuli-triggered self-assembly on gold nanoparticles and introduce the breakthrough of gold nanoparticles in disease diagnosis and treatment. In addition, the current challenge and future prospective of stimuli-responsive gold nanoparticles for biomedical applications are discussed.

Abstract

Gold nanoparticles have been widely used in engineering, material chemistry, and biomedical applications owing to their ease of synthesis and functionalization, localized surface plasmon resonance (LSPR), great chemical stability, excellent biocompatibility, tunable optical and electronic property. In recent years, the decoration and modification of gold nanoparticles with small molecules, ligands, surfactants, peptides, DNA/RNA, and proteins have been systematically studied. In this review, we summarize the recent approaches on stimuli-triggered self-assembly of gold nanoparticles and introduce the breakthrough of gold nanoparticles in disease diagnosis and treatment. Finally, we discuss the current challenge and future prospective of stimuli-responsive gold nanoparticles for biomedical applications.

A metal free photoredox strategy for alkenyl C−H arylation has been developed for the first time to synthesize a diverse range of 4-aryl coumarin-2-oxo-3-carboxylate derivatives.

Abstract

The present work represents a novel methodology for the selective arylation of coumarin-3-carboxylates with arylboronic acids via a photochemical route, marking the first-ever attempt for the direct alkenyl C−H arylation using rose bengal as a photocatalyst, which is a readily available and cost-effective alternative to transition metal catalysis. The reaction proceeds smoothly in MeOH/H₂O solvent media in the presence of radical initiator affording the arylated products in good yields (60–80 %). The reaction parameters such as visible light, radical initiator, oxidant, anhydrous solvent, and inert atmosphere play a crucial role for the success of this methodology. The substituents present on the substrate show a significant effect on the conversion. This study provides a valuable contribution to the field of organic synthesis offering a new and efficient approach to the arylation of coumarin-3-carboxylic acid esters with a broad substrate scope and high functional group tolerance. It is a versatile method and provides a direct access to biologically relevant 4-arylcoumarin-3-carboxylates.

This study advances our understanding of As(III) interactions in biological systems, revealing the important role of pnictogen bonding in As(III) S-adenosylmethionine methyltransferases. The noncovalent As⋅⋅⋅O pnictogen bonds have been analyzed energetically and characterized studied using a variety of computational tools.

Abstract

As(III) S-adenosylmethionine methyltransferases, pivotal enzymes in arsenic metabolism, facilitate the methylation of arsenic up to three times. This process predominantly yields trivalent mono- and dimethylarsenite, with trimethylarsine forming in smaller amounts. While this enzyme acts as a detoxifier in microbial systems by altering As(III), in humans, it paradoxically generates more toxic and potentially carcinogenic methylated arsenic species. The strong affinity of As(III) for cysteine residues, forming As(III)-thiolate bonds, is exploited in medical treatments, notably in arsenic trioxide (Trisenox®), an FDA-approved drug for leukemia. The effectiveness of this drug is partly due to its interaction with cysteine residues, leading to the breakdown of key oncogenic fusion proteins. In this study, we extend the understanding of As(III)′s binding mechanisms, showing that, in addition to As(III)−S covalent bonds, noncovalent O⋅⋅⋅As pnictogen bonding plays a vital role. This interaction significantly contributes to the structural stability of the As(III) complexes. Our crystallographic analysis using the PDB database of As(III) S-adenosylmethionine methyltransferases, augmented by comprehensive theoretical studies including molecular electrostatic potential (MEP), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) analysis, emphasizes the critical role of pnictogen bonding in these systems. We also undertake a detailed evaluation of the energy characteristics of these pnictogen bonds using various theoretical models. To our knowledge, this is the first time pnictogen bonds in As(III) derivatives have been reported in biological systems, marking a significant advancement in our understanding of arsenic‘s molecular interactions.

We report a microwave-assisted wet chemical method for doping Zn into SnTe thermoelectric materials to in-situ induce rich ZnTe nanoprecipitates, nanopores, a large number of grain boundaries and other multi-dimensional defects. While ensuring competitive electrical transport performance, the introduced multi-dimensional defects induced phonon scattering across the entire scale, reducing the lattice thermal conductivity of SnTe to the amorphous limit and enhancing its thermoelectric performance.

Abstract

The creation of hierarchical nanostructures can effectively strengthen phonon scattering to reduce lattice thermal conductivity for improving thermoelectric properties in inorganic solids. Here, we use Zn doping to induce a remarkable reduction in the lattice thermal conductivity in SnTe, approaching the theoretical minimum limit. Microstructure analysis reveals that ZnTe nanoprecipitates can embed within SnTe grains beyond the solubility limit of Zn in the Zn alloyed SnTe. These nanoprecipitates result in a substantial decrease of the lattice thermal conductivity in SnTe, leading to an ultralow lattice thermal conductivity of 0.50 W m⁻¹ K⁻¹ at 773 K and a peak ZT of ~0.48 at 773 K, marking an approximately 45 % enhancement compared to pristine SnTe. This study underscores the effectiveness of incorporating ZnTe nanoprecipitates in boosting the thermoelectric performance of SnTe-based materials.

Salan-based Ti(IV) complexes react with ^t BuNCO leading to the insertion of one or two isocyanate molecules into Ti-N_salan bonds. Conversely, the reaction of [(L*)Ti(NHMe₂)₂] (L*=N₂O₂ ⁴⁻) with CO₂ reveals its insertion into Ti-NHMe₂ bonds. The insertion of heteroallenes into Ti−N bonds offers the possibility to use them to functionalize salan ligands or as building blocks to prepare high-value-added compounds.

Abstract

The reaction of Ti(NMe₂)₄ with the salan ligand precursor H₂N₂O₂H₂ led to the formation of [(L*)Ti(NHMe₂)₂] (L*=N₂O₂ ⁴⁻) that forms [(H₂N₂O₂)TiCl₂] upon reaction with two equiv. of Me₃SiCl. [(L*)Ti(py)₂] was obtained from the reaction of [Ti(N ^t Bu)Cl₂(py)₃] with the sodium salt H₂N₂O₂Na₂. Treatment of [(L*)Ti(NHMe₂)₂] with two equiv. of ^t BuNCO led to the insertion of the isocyanate molecules into the Ti−N_salan bonds with the formation of [{L*(N(^tBu)CO)₂}Ti]. Conversely, the reaction of [(H₂N₂O₂)Ti(OⁱPr)₂] with two equiv. of ^t BuNCO led to the insertion of one isocyanate molecule into a Ti−N_salan bond with the formation of [{(HN₂O₂)(N( ^t Bu)CO)}Ti(OⁱPr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan-based Ti(IV) complexes.

Herein, we synthesized pillar[6]arene derivatives having alternate methylene and nitrogen bridges. Owing to the charge transfer emission, the solid-state photoluminescence quantum yield (Φ_PL) was enhanced compared with that of the parent pillar[6]arene (Φ_PL=0.063→Φ_PL=0.36). Furthermore, it displayed a turn-off sensing toward nitrobenzene (NB) vapor; a fluorescence quenching was observed when exposed to the NB vapor.

Abstract

Macrocyclic arenes show conformational adaptability, which allows host–guest complexations with the size-matched guest molecules. However, their emission properties are often poor in the solid states due to the self-absorption. Herein, we newly synthesized pillar[6]arene derivatives having alternate methylene and nitrogen bridging structures. Solvatochromic study reveals that the nitrogen-embedding into the cyclic structures can strengthen the intramolecular charge transfer (CT) nature compared to that of the linear nitrogen-bridged precursor. Owing to the large Stokes shift in the solid state, one of the nitrogen-embedded pillar[6]arenes shows high absolute photoluminescence quantum yield (Φ_PL=0.36). Furthermore, it displays a turn-off sensing ability toward nitrobenzene (NB) vapor; a fluorescence quenching is observed when exposed to the NB vapor. From the structural analysis before and after the exposure of NB vapor, the amorphous nitrogen-embedded pillar[6]arene efficiently co-crystallize with NB and formed non-emissive intermolecular CT complexes with NB.