Incorporating Rare-Earth Terbium(III) Ions into Cs2AgInCl6:Bi Nanocrystals toward Tunable Photoluminescence

The incorporation of impurity ions or doping is a promising method for controlling the electronic and optical properties and the structural stability of halide perovskite nanocrystals (NCs). Herein, we establish relationships between rare-earth ions doping and intrinsic emission of lead-free double perovskite Cs₂AgInCl₆ NCs to impart and tune the optical performances in the visible light region. Tb³⁺ ions were incorporated into Cs₂AgInCl₆ NCs and occupied In³⁺ sites as verified by both crystallographic analyses and first-principles calculations. Trace amounts of Bi doping endowed the characteristic emission (⁵D₄→⁷F_6-3) of Tb³⁺ ions with a new excitation peak at 368 nm rather than the single characteristic excitation at 290 nm of Tb³⁺. By controlling Tb³⁺ ions concentration, the emission colors of Bi-doped Cs₂Ag(In_1−xTb_x)Cl₆ NCs could be continuously tuned from green to orange, through the efficient energy-transfer channel from self-trapped excitons to Tb³⁺ ions. Our study provides the salient features of the material design of lead-free perovskite NCs and to expand their luminescence applications.     

Stereospecific 1,2-Migrations of Boronate Complexes Induced by Electrophiles

The stereospecific 1,2-migration of boronate complexes is one of the most representative reactions in boron chemistry. This process has been used extensively to develop powerful methods for asymmetric synthesis, with applications spanning from pharmaceuticals to natural products. Typically, 1,2-migration of boronate complexes is driven by displacement of an α-leaving group, oxidation of an α-boryl radical, or electrophilic activation of an alkenyl boronate complex. The aim of this article is to summarize the recent advances in the rapidly expanding field of electrophile-induced stereospecific 1,2-migration of groups from boron to sp² and sp³ carbon centers. It will be shown that three different conceptual approaches can be utilized to enable the 1,2-migration of boronate complexes: stereospecific Zweifel-type reactions, catalytic conjunctive coupling reactions, and transition metal-free sp²–sp³ couplings. A discussion of the reaction scope, mechanistic insights, and synthetic applications of the work described is also presented.     

The Fe-N-C Nanozyme with Both Accelerated and Inhibited Biocatalytic Activities Capable of Accessing Drug–Drug Interactions

Emerging as a cost-effective and robust enzyme mimic, nanozymes have drawn increasing attention with broad applications ranging from cancer therapy to biosensing. Developing nanozymes with both accelerated and inhibited biocatalytic properties in a biological context is intriguing to peruse more advanced functions of natural enzymes, but remains challenging, because most nanozymes are lack of enzyme-like molecular structures. By re-visiting and engineering the well-known Fe-N-C electrocatalyst that has a heme-like Fe-N_x active sites, herein, it is reported that Fe-N-C could not only catalyze drug metabolization but also had inhibition behaviors similar to cytochrome P450 (CYP), endowing it a potential replacement of CYP for preliminary evaluation of massive potential chemicals, drug dosing guide, and outcome prediction. In addition, in contrast to electrocatalysts, the highly graphitic framework of Fe-N-C may not be obligatory for a competitive CYP-like activity.     

Cellular Synthesis and X-ray Crystal Structure of a Designed Protein Heterocatenane

Herein, we report the biosynthesis of protein heterocatenanes using a programmed sequence of multiple post-translational processing events including intramolecular chain entanglement, in situ backbone cleavage, and spontaneous cyclization. The approach is general, autonomous, and can obviate the need for any additional enzymes. The catenane topology was convincingly proven using a combination of SDS-PAGE, LC-MS, size exclusion chromatography, controlled proteolytic digestion, and protein crystallography. The X-ray crystal structure clearly shows two mechanically interlocked protein rings with intact folded domains. It opens new avenues in the nascent field of protein-topology engineering.     

Cross-Linked Polyphosphazene Hollow Nanosphere-Derived N/P-Doped Porous Carbon with Single Nonprecious Metal Atoms for the Oxygen Reduction Reaction

Heteroatom-doped polymers or carbon nanospheres have attracted broad research interest. However, rational synthesis of these nanospheres with controllable properties is still a great challenge. Herein, we develop a template-free approach to construct cross-linked polyphosphazene nanospheres with tunable hollow structures. As comonomers, hexachlorocyclotriphosphazene provides N and P atoms, tannic acid can coordinate with metal ions, and the replaceable third comonomer can endow the materials with various properties. After carbonization, N/P-doped mesoporous carbon nanospheres were obtained with small particle size (≈50 nm) and high surface area (411.60 m² g⁻¹). Structural characterization confirmed uniform dispersion of the single atom transition metal sites (i.e., Co-N₂P₂) with N and P dual coordination. Electrochemical measurements and theoretical simulations revealed the oxygen reduction reaction performance. This work provides a solution for fabricating diverse heteroatom-containing polymer nanospheres and their derived single metal atom doped carbon catalysts.     

ZIF-Induced d-Band Modification in a Bimetallic Nanocatalyst: Achieving Over 44 % Efficiency in the Ambient Nitrogen Reduction Reaction

The electrochemical nitrogen reduction reaction (NRR) offers a sustainable solution towards ammonia production but suffers poor reaction performance owing to preferential catalyst–H formation and the consequential hydrogen evolution reaction (HER). Now, the Pt/Au electrocatalyst d-band structure is electronically modified using zeolitic imidazole framework (ZIF) to achieve a Faradaic efficiency (FE) of >44 % with high ammonia yield rate of >161 μg mg_cat⁻¹ h⁻¹ under ambient conditions. The strategy lowers electrocatalyst d-band position to weaken H adsorption and concurrently creates electron-deficient sites to kinetically drive NRR by promoting catalyst–N₂ interaction. The ZIF coating on the electrocatalyst doubles as a hydrophobic layer to suppress HER, further improving FE by >44-fold compared to without ZIF (ca. 1 %). The Pt/Au-N_ZIF interaction is key to enable strong N₂ adsorption over H atom.     

A Fully Non-fused Ring Acceptor with Planar Backbone and Near-IR Absorption for High Performance Polymer Solar Cells

Fused-ring electron acceptors have made significant progress in recent years, while the development of fully non-fused ring acceptors has been unsatisfactory. Here, two fully non-fused ring acceptors, o-4TBC-2F and m-4TBC-2F, were designed and synthesized. By regulating the location of the hexyloxy chains, o-4TBC-2F formed planar backbones, while m-4TBC-2F displayed a twisted backbone. Additionally, the o-4TBC-2F film showed a markedly red-shifted absorption after thermal annealing, which indicated the formation of J-aggregates. For fabrication of organic solar cells (OSCs), PBDB-T was used as a donor and blended with the two acceptors. The o-4TBC-2F-based blend films displayed higher charge mobilities, lower energy loss and a higher power conversion efficiency (PCE). The optimized devices based on o-4TBC-2F gave a PCE of 10.26 %, which was much higher than those based on m-4TBC-2F at 2.63 %, and it is one of the highest reported PCE values for fully non-fused ring electron acceptors.     

Research on gamma-ray irradiation-assisted synthesis of cross-linked polystyrene via bulk polymerization

Journal of Radioanalytical and Nuclear Chemistry - Controlling heat accumulation is one of the major challenges for block materials synthesizing via bulk polymerization. In the paper, cross-linked...     

Quick stabilization of capillary for rapid determination of potassium ions in the blood of epilepsy patients by capillary electrophoresis without sample pretreatment

Mutations in the potassium channel genes may be linked to the development of epilepsy and affect the blood potassium levels. Therefore, accurate determination of potassium in the blood will be critical to diagnose the cause of epilepsy. CE is a competent technique for the fast detection of multiple ions, but complicated matrices of a blood sample may cause significant variation of migration times and the peak shape. In this work, a procedure for rapid stabilization of the capillary inner surface through preflushing of a blood sample was employed. The process takes only 40 min for a capillary and then it can be used for more than 2 weeks. No pretreatment of the blood sample or other surface modification of the capillary is needed for the analysis. The RSDs of the migration time and peak area were reduced to 1.5 and 5.1% from 12.6 and 14.5%, respectively. The proposed method has been successfully applied to the determination of the potassium contents in the blood sample of patients with epilepsy at different stages. The recoveries of potassium ions in these blood samples are in a range from 86.5 to 104.5%.     

Characterization of sequence variation at 30 autosomal STRs in Chinese Han and Tibetan populations

Massively parallel sequencing (MPS) technologies have the ability to reveal sequence variations within STR alleles as well as their nominal allele lengths, which have traditionally been detected by CE instruments. Recently, Thermo Fisher Scientific has updated the MPS-STR panel, named the Precision ID GlobalFiler next-generation sequencing (NGS) STR Panel version 2, with primers redesigned to add two pentanucleotide tandem repeat loci and profile interpretation supported by the Converge software. Using the Ion Chef System, the Ion S5XL System, and the Converge software, genetic variations were characterized within STR repeat and flanking regions of 30 autosomal STR markers in 115 unrelated individuals from two Chinese population groups (58 Tibetans and 57 Hans). Nineteen STRs demonstrated a relative increase in diversity with the variant sequence alleles compared with those of traditional nominal length alleles. In total, 390 alleles were identified by their sequences compared with 258 alleles that were identified by length. Of these 92 sequence variants found within the STR repeat regions, 40 variants were located in STR flanking regions. Additionally, the agreement of the results with CE data was evaluated, as was the ability of this new MPS panel to analyze case-type (11 samples) and artificially degraded samples (seven samples in triplicate). The results generated from this study illustrate that extensive sequence variation exists in commonly used STR markers in the selected population samples and indicate that this NGS STR panel has the potential to be used as an effective tool for human forensics.