Chemistry Design Towards a Stable Sulfide‐Based Superionic Conductor Li4Cu8Ge3S12

Sulfide‐based superionic conductors with high ionic conductivity have been explored as candidates for solid‐state Li batteries. However, moisture hypersensitivity has made their manufacture complicated and costly and also impeded applications in batteries. Now, a sulfide‐based superionic conductor Li₄Cu₈Ge₃S₁₂ with superior stability was developed based on the hard/soft acid–base theory. The compound is stable in both moist air and aqueous LiOH aqueous solution. The electrochemical stability window was up to 1.5 V. An ionic conductivity of 0.9×10^?4 S cm with low activation energy of 0.33 eV was achieved without any optimization. The material features a rigid Cu‐Ge‐S open framework that increases its stability. Meanwhile, the weak bonding between Li⁺ and the framework promotes ionic conductivity. This work provides a structural configuration in which weak Li bonding in the rigid framework promotes an environment for highly conductive and stable solid‐state electrolytes.     

Orthogonal Halogen‐Bonding‐Driven 3D Supramolecular Assembly of Right‐Handed Synthetic Helical Peptides

Peptide‐mediated self‐assembly is a prevalent method for creating highly ordered supramolecular architectures. Herein, we report the first example of orthogonal C?X???X?C/C?X???π halogen bonding and hydrogen bonding driven crystalline architectures based on synthetic helical peptides bearing hybrids of l ‐sulfono‐γ‐AApeptides and natural amino acids. The combination of halogen bonding, intra‐/intermolecular hydrogen bonding, and intermolecular hydrophobic interactions enabled novel 3D supramolecular assembly. The orthogonal halogen bonding in the supramolecular architecture exerts a novel mechanism for the self‐assembly of synthetic peptide foldamers and gives new insights into molecular recognition, supramolecular design, and rational design of biomimetic structures.     

Catalytic Kinetic Resolution by Enantioselective Aromatization: Conversion of Racemic Intermediates of the Barton–Zard Reaction into Enantioenriched 3‐Arylpyrroles

Racemic 3,4‐dihydro‐2H‐pyrroles, hypothetical intermediates of the Barton–Zard reaction, were synthesized in a highly diastereoselective manner and fully characterized for the first time. Kinetic resolution of the dihydropyrroles with a quinine‐derived thiourea afforded the (+)‐3‐arylpyrrole products and recovered (+)‐3,4‐dihydro‐2H‐pyrroles with high efficiency (s‐factor up to 153). The resolved (+)‐3,4‐dihydro‐2H‐pyrroles underwent subsequent aromatization with a quinidine‐derived thiourea catalyst to afford (?)‐3‐arylpyrroles with excellent central‐to‐axial chirality transfer. In contrast to the well‐accepted Barton–Zard mechanism, the aromatization of the 3,4‐dihydro‐2H‐pyrroles in the presence of a bifunctional catalyst is believed to proceed by an unprecedented sequence involving syn elimination of HNO₂ and aromatization.     

Synthesis of Indoles through Domino Reactions of 2‐Fluorotoluenes and Nitriles

Indoles are essential heterocycles in medicinal chemistry, and therefore, novel and efficient approaches to their synthesis are in high demand. Among indoles, 2‐aryl indoles have been described as privileged scaffolds. Advanced herein is a straightforward, practical, and transition‐metal‐free assembly of 2‐aryl indoles. Simply combining readily available 2‐fluorotoluenes, nitriles, LiN(SiMe₃)₂, and CsF enables the generation of a diverse array of indoles (38 examples, 48–92 % yield). A range of substituents can be introduced into each position of the indole backbone (C4 to C7, and aryl groups at C2), providing handles for further elaboration.     

Carbon Dots as a New Class of Diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI Contrast Agents

While carbon dots (C‐dots) have been extensively investigated pertaining to their fluorescent, phosphorescent, electrochemiluminescent, optoelectronic, and catalytic features, their inherent chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) properties are unknown. By virtue of their hydrophilicity and abundant exchangeable protons of hydroxyl, amine, and amide anchored on the surface, we report here that C‐dots can be adapted as effective diamagnetic CEST (diaCEST) MRI contrast agents. As a proof‐of‐concept demonstration, human glioma cells were labeled with liposomes with or without encapsulated C‐dots and implanted in mouse brain. In vivo CEST MRI was able to clearly differentiate labeled cells from non‐labeled cells. The present findings may encourage new applications of C‐dots for in vivo imaging in deep tissues, which is currently not possible using conventional fluorescent (near‐infrared) C‐dots.     

应用体外仿生模型分析海藻水煎液中微量金属的形态和生物可给性

将体外半仿生消化和全仿生消化法分别应用于海藻分析前处理,即模拟人体消化环境,加入消化液所含有机物和无机物,模拟海藻(海带和紫菜)水煎液在胃肠中的吸收和转运机制.鉴于消化管和血管间的生物膜是类脂质膜,以单层脂质体为细胞生物膜模型考察海藻水煎液中微量金属在单层脂质体-水体系中的分配行为.以单层脂质体结合态、水溶态界定水煎液中微量金属的形态; 以单层脂质体结合态含量评价微量金属的生物可给性; 比较单层脂质体结合态金属在胃肠中浓度,确定微量金属的主要吸收部位.消化酶对海藻中微量元素的形态和生物可给性影响明显.水煎液全仿生消化后,海带和紫菜中的Fe均主要在胃被吸收,海带中的Mn和Zn主要在肠被吸收;紫菜中的Mn和Zn在胃与肠均有吸收.     

米氏酸在杂环化合物合成中的应用研究进展

综述了近年来米氏酸在杂环化合物合成中的应用,涉及到吡喃环、吡啶环、呋喃环、吡咯环、噁唑环和异噁唑环重要杂环的形成.大多具有反应条件温和、便利、产率较高等优点.     

卟啉-碳纳米管复合物研究进展

碳纳米管是具有一维纳米结构的新型纳米材料,具有许多独特的物理、化学性质.卟啉对可见光具有强烈吸收,其大π共轭体系使其具有良好的电子给予能力,可作为人工光合作用体系的光捕捉单元.将具有电子接受能力的碳纳米管与卟啉结合起来,通过卟啉对碳纳米管进行共价和非共价修饰,可以改善碳纳米管在溶剂中的溶解分散性能,同时实现卟啉和碳纳米管之间有效的电子传递,形成具有独特光电和光学性质卟啉-碳纳米管复合物.该类物质具备良好的应用前景,是碳纳米管和卟啉研究中的热点.就近年来该类复合物的构筑方法及性质研究等方面的进展进行了综述.     

Synthesis of Novel Spiro Pyrrolidine and Pyrrolizine Derivatives by 1,3-Dipolar Cycloaddition

The 1,3‐dipolar cycloaddition of azomethine ylides derived from isatin and amino acids viz. sarcosine and proline to 2‐arylmethylidene‐5,6‐dihydroimidazo[2,1‐b]thiazol‐3(2H)‐ones afforded novel spiro pyrrolidines and pyrrolizidines regio‐ and stereoselectively in moderate yields. The products were characterized thoroughly by IR, MS, NMR together with elementary analysis.