Latest ArticlesGaining an understanding of the growth mechanism from single atoms to clusters and bulk materials continues to present a challenge. Thus, it is important to explore the evolving trends of clusters in the structure and properties during the size evolution. In this work, we report the synthesis and characterization of two medium-sized chain-like polyarsenic anions. [As21]3– represents a trimeric example of polyarsenic anion assembled through oxidative coupling of As73– anions. The anion As184– included in [As18Mo2(CO)8]4– is regarded as formed by two realgar-type As8 subunits connected by a dinuclear As-As dumbbell. The As18 cluster was previously predicted by theory, and this is the first time successfully synthesized using wet chemistry method. Besides, small-sized polyarsenides As22– and As102– were found in compound [K(18-crown-6)]3[As10]0.5[As4{Mo(CO)3}2]0.5·2en. Among these, the former exhibits coordination with metal atoms. Single-crystal X-ray diffraction combined with quantum chemical calculations revealed the formation of double bonded As22– stabilized by metal carbonyl groups. This work demonstrates a novel synthetic approach for the preparation of new polyarsenides and highlights their intriguing bonding characteristics, laying the foundation for the synthesis of such compounds and paving the way for their potential applications.
Four new cyclohexapeptides, pyridapeptides F–I (1–4), were isolated from the fermentation broth of marine sponge-derived Streptomyces sp. OUCMDZ-4539. The pyridapeptides F–H (1–3) are composed of β-hydroxyleucine, alanine, O-methylthreonine, hexahydropyridazine-3-carboxylic acid, 5-hydroxytetrahydropyridazine-3-carboxylic acid, and (2S,3R,4E,6E)-2-amino-3–hydroxy-4,6-dienoic acid residues. Pyridapeptide Ⅰ (4) contains (2S,3R,4E,6E)-2-amino-3–hydroxy-8-methylnona-4,6-dienoic acid residue and a very rare glycose residue, aculose. Their structures were determined based on spectroscopic analysis and chemical methods. Pyridapeptides G–I (2–4) have the 2,3,6-trideoxyhexose units glycosylated at the γ-OH-TPDA residue, displayed significant antiproliferative activity against four (PC9, MKN45, HepG2, K562) or two (PC9, MKN45) human cancer cell lines.
The efficient and environmentally friendly recycling technology of waste residue that including abundant heavy metal produced during the recovery of lithium batteries has become a research hotspot. Herein, a novelty process of acid leaching-selective electrodeposition-deep impurity removal-regeneration was proposed to recovery of the CuS slag, which has been efficient transferred to high purity cathode copper and commercially available ternary precursors. Copper cathode with a purity of 99.67% was prepared under electrochemical reaction conditions at −0.55 V for 2 h. A novel impurity remover-Mn powder, which was used to remove the residual impurities and as a feedstock for the ternary precursor. Finally, NCM523 was regenerated by co-precipitation. The process is superior to the traditional process in economy, energy consumption, CO2 emissions, product purity and process duration. This study provides a new approach for solid waste recovery and precious metal enrichment.
Zero thermal expansion materials are important for the practical applications due to their shape stability as changing temperature. The reported concept of average atomic volume is an available method to hunt new zero thermal expansion materials. Here, according to this concept, a tetragonal tungstate Cs2W3O10 with zero expansion has been found. There is no structure phase transition as increasing temperature from 150 K to 573 K. The coefficient of thermal expansion of axes and volume are αa = 0.0074 × 10−6 K−1, αc = 1.63 × 10−6 K−1, and αV = 1.60 × 10−6 K−1, respectively, in the temperature range of 150 ~ 573 K. The temperature- and pressure-dependent Raman spectra reveal that the vibrations of WO6 octahedra libration modes with positive total anharmonicity and W-O-W bending mode with negative Grüneisen parameter are possibly the origin of zero thermal expansion in Cs2W3O10.
The preparation of Pd-based catalysts with rich electrons and a high atom dispersion rate is of great significance for improving the reactivity of cross-coupling reactions, which is a powerful tool for pharmaceutical and fine chemical synthesis. Here, we report a PdNi single-atom alloy (SAA) catalyst in which isolated Pd single atoms are anchored onto the surface of Ni nanoparticles (NPs) applied for Suzuki coupling reactions and Heck coupling reactions. The 0.1% PdNi SAA exhibits extraordinary catalytic activity (reaction rate: 17,032.25 mmol h−1 gPd−1) toward the Suzuki cross-coupling reaction between 4-bromoanisole and phenylboronic acid at 80℃ for 1 h. The excellent activity is supposed to attribute to the 100 percent utilization rate of Pd atoms and the highly stable surface zero-valance Pd atoms, which provides abundant sites and electrons for the adsorption and fracture of the C-X (X = Cl, Br, I) bond. Moreover, our work demonstrates the excellent application prospect of SAAs for cross-coupling reactions.
All solid-state lithium metal batteries (ASSLMBs) based on polymer solid electrolyte and lithium metal anode have attracted much attention due to their high energy density and intrinsic safety. However, the low ionic conductivity at room temperature and poor mechanical properties of the solid polymer electrolyte result in increased polarization and poor cycling stability of the Li metal batteries. In order to improve the ionic conductivity at room temperature while maintaining mechanical strength, we combine the conductivity of short chain polyethylene oxide (PEO) and strength of styrene-maleic anhydride copolymer (SMA) to obtain a grafted block copolymer with nanophase separation structure, which has room temperature ionic conductivity up to 1.14 × 10−4 S/cm and tensile strength up to 1.4 MPa. Li||Li symmetric cell can work stably for more than 1500 h under the condition of 0.1 mA/cm2. Li||LiFePO4 full cells can deliver a high capacity of 151.4 mAh/g at 25 ℃ and 0.2 C/0.2 C charge/discharge conditions, showing 85.6% capacity retention after 400 cycles. Importantly, the all solid state Li||LiFePO4 pouch cell shows excellent safety performance under different abuse conditions. These results demonstrate that the nanophase separated, grafted alternate copolymer electrolyte has huge potential for application in Li metal batteries.
Fungal alkylresorcinols are a class of polyketides, which are commonly synthesized by the hybridization of highly reducing polyketide synthase (hrPKS) with non-reducing polyketide synthase (nrPKS). In this study, we identified and demonstrated a new assembly model for synthesizing alkylresorcinol (scirpilin A, 1), which was accomplished by collaboration of a hrPKS (FscA) and a type Ⅲ PKS (FscB). Furthermore, three post-tailoring enzymes (FscC, FscD, and FscE) act iteratively on 1 skeleton, including successive 14e− oxidation of inert carbons, di-halogenation, and di-methylation, to form highly oxidized and multi-substituted alkylresorcinols. Our work presents an unusual synthesis manner of alkylresorcinols, sheds light on the collaborative mechanism between hrPKS and type Ⅲ PKS and provides three valuable enzymatic catalysts for the tailoring of alkylresorcinol family natural products in future.
Dynamic assembly on time scale is common in biological systems but rare for artificial materials, especially for smart luminescent materials. Programming molecular assembly in a spatio-temporal manner and resulting in white-light-including multicolor fluorescence with time-dynamic features remains challenging. Herein, controlling molecular assembly on time scale is achieved by integrating a pH-responsive motif to a transient alkaline solution which is fabricated by activators (NaOH) and deactivators (esters), leading to automatic assembly on time scale and time-dependent multicolor fluorescence changing from blue to white and yellow. The kinetics of the assembly process is dependent on the ester hydrolysis process, which can be controlled by varying ester concentrations, temperature, initial pH, stirring rate and ester structures. This dynamic fluorescent system can be further developed for intelligent fluorescent materials such as fluorescent ink, three-dimension (3D) codes and even four-dimension (4D) codes, exhibiting a promising potential for information encryption.
To surmount the obstacles of traditional Fenton method and synchronously utilize Cu2+ and polyphenol in water, an improved Fenton-like reaction applying calcium peroxide (CaO2) as H2O2 source and regulating by the complex of Cu2+-tartaric acid (TA, a representative of polyphenol) was constructed. A typical antibiotic, metronidazole (MTZ) could be effectively eliminated by the Cu2+/TA/CaO2 system, and the optimized parameters were as follows: 0.1 mmol/L Cu2+, 2 mmol/L TA, 2 mmol/L CaO2, and initial pH 5. UV spectrum confirmed the formation of Cu2+-TA complex, which promoted the Cu2+/Cu+ circulation through decreasing the Cu2+/Cu+ couple redox potential, which further enhanced the H2O2 decomposition and the formation of reactive species. Hydroxyl radical was dominant for MTZ degradation, followed by oxygen and superoxide radical. The degradation intermediates of MTZ were detected and their evolution way was speculated. Furthermore, the ternary process showed a wide pH tolerance (3–8) for removing MTZ and broad applicability for eliminating other dyes and antibiotics. This work provided a reference for Cu-based Fenton-like strategy for organic wastewater settlement.
Anticancer platinum prodrugs that can be controllably activated are highly desired for personalized precision medicine and patient compliance in cancer therapy. However, the clinical application of platinum(Ⅳ) prodrugs (Pt(Ⅳ)) is restricted by tissue penetration of external irradiation. Here, we report a novel Pt(Ⅳ) activation strategy based on endogenous luminescence of tumor microenvironment responsiveness, which completely circumvents the limitation of external irradiation. The designed Pt(Ⅳ)Lu, a mixture of trans, trans, trans-[Pt(N3)2(OH)2(py)2] and luminol (Lu), has controllable activation property: it remains inert in reductant environment and normal tissues, but under tumor microenvironment, Lu will be oxidized to produce blue luminescence, which rapidly reduce Pt(Ⅳ) to Pt(Ⅱ) without the need of any external activator. Pt(Ⅳ)Lu shows excellent responsive antitumor ability both in vitro and in vivo. Compared to cisplatin, the median lethal dose in BALB/c mice increased by an order of magnitude. Our results suggest that Pt(Ⅳ)Lu exhibits highly controllable activation property, superior antitumor activity, and good biosafety, which may provide a novel strategy for the design of platinum prodrugs.
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