Enantioselective carboxylative cyclization of propargylic alcohol with carbon dioxide under mild conditions

An enantioselective carboxylative cyclization of propargylic alcohols and CO2 was realized under mild conditions,based on a kinetic resolution strategy,which enabled the synthesis of chiral cyclic carbonates and propargylic alcohols with promising yield and enantioselectivity simultaneously.     

Recent advances in metal-organic frameworks for lithium metal anode protection

The lithium metal battery has been considered as a promising candidate for next generation batteries.However,safety concerns caused by uncontrollable lithium dendrite growth on lithium anode are severely hampering the commercial application.Metal-organic frameworks(MOFs)become one of the most attractive materials due to the high porosity,structural designability and tunability.With unique open channels and pores as well as functional components in MOFs,the transportation and deposition of lithium ions can be regulated,which leads to enhanced electrochemical prope rties.Various strategies for lithium metal protection are proposed in recent wo rks on applications of MOFs in lithium metal batteries.In this review,we highlight latest key approaches in this field and discuss the prospects for MOFs in advanced Li anodes.     

二维磁性纳米材料的可控合成及磁性调控

自旋电子学的研究重点在于同时利用电子的电荷和自旋两个自由度对信息进行处理和存储,其具有运行速度快、存储密度高和能耗低等优势。毫无疑问,发展二维磁性纳米材料的可控合成方法及磁性调控策略,对于新型自旋电子学器件的构筑具有重要的科学意义和应用价值。然而,目前得到的二维磁性纳米材料的种类十分有限,而且合成方法及磁性调控手段相对单一,极大地限制了该领域的发展。本文首先根据磁性的来源,对二维磁性纳米材料进行了分类,介绍了诱导产生的磁性和具有本征磁性的二维纳米材料,然后详细地归纳了二维磁性纳米材料常见的合成方法,如机械剥离法、电化学剥离法、化学气相沉积法以及液相合成方法等。此外,着重总结了二维材料磁性的主要调控手段,最后展望了该领域遇到的瓶颈、未来的研究重点及应用前景。     

自支撑硫镍基电极材料制备及其赝电容性能

硫镍基赝电容超级电容器具有较高的比电容和功率密度等优点,是下一代理想的储能装置之一,但其实际应用受到其活性材料的制约,如导电性低和循环性能差等。研究者围绕增强硫镍基赝电容电极材料导电性和提升循环稳定性进行了大量的研究工作。其中,构建自支撑的电极材料被认为是一种降低活性材料和集流体之间界面电阻的有效方法。本文综述了制备自支撑硫镍基赝电容电极的常见方法,并就活性材料的形貌与性能关系进行了总结,主要着眼于集流体改性、离子掺杂、复合材料构建及形貌调控优化等。最后对自支撑硫镍基赝电容电极材料的研究方向进行了展望。     

聚吡咯及其纳米复合材料在光热治疗领域的应用

光热治疗是近年来兴起的一种治疗方法,具有靶向性强、适应性广的特点。在光热治疗中,通过光热剂对光的吸收将光能转化为热能,从而实现治疗作用,因而光热剂的光热转化性能直接决定了光热治疗的效果。光热剂的种类丰富,涵盖由无机到有机等组成和性能各异的多种材料。其中,聚吡咯具备良好的生物相容性、优异的光稳定性以及光热转化性能,在光热治疗领域受到广泛关注,是一种拥有巨大应用潜力的光热剂,然而其在光热治疗领域的发展趋势及前景却鲜有报道。本文综述了聚吡咯及其纳米复合材料的制备方法,详述了聚吡咯及其纳米复合材料在光热治疗领域中的应用情况,包括聚吡咯基纳米材料的自身性能和实际光热治疗的效果,指出以聚吡咯为基体或修饰材料来制备具有CT、磁共振、光声显影及光热治疗性能的聚吡咯基复合材料已成为发展趋势。在此基础上,本文还总结了聚吡咯基纳米复合材料在制备和应用中存在的问题,并分析了其在发展过程中遇到的挑战以及在生物医学应用中的前景。     

Excitation‐Dependent Long‐Life Luminescent Polymeric Systems under Ambient Conditions

Organic room temperature luminescent materials present a unique phosphorescence emission with a long lifetime. However, many of these materials only emit single blue or green color in spite of external stimulation, and their color tunability is limited. Herein, we report a rational design to extend the emission color range from blue to red by controlling the doping of simple pyrene derivatives into a robust polymer matrix. The integration of these pyrene molecules into the polymer films enhances the intersystem crossing pathway, decreases the first triplet level of the system, and ensures the films show a sensitive response to excitation energy, finally yielding excitation‐dependent long‐life luminescent polymeric systems under ambient conditions. These materials were used to construct anti‐counterfeiting patterns with multicolor interconversion, presenting a promising application potential in the field of information security.     

Water Catalysis of the Reaction of Methanol with OH Radical in the Atmosphere is Negligible

Faced with the contradictory results of two recent experimental studies [Jara‐Toro et al., Angew. Chem. Int. Ed. 2017 , 56, 2166 and Chao et al., Angew. Chem. Int. Ed. 2019 , 58, 5013] of the possible catalytic effect of water vapor on CH₃OH + OH reaction, we report calculations that corroborate the conclusion made by Chao et al. and extend the rate constant evaluation down to 200 K. The rate constants of the CH₃OH + OH reaction catalyzed by a water molecule are computed as functions of temperature and relative humidity using high‐level electronic structure and kinetics calculations. The Wuhan–Minnesota Scaling (WMS) method is used to provide accurate energetics to benchmark a density functional for direct dynamics. Both high‐frequency and low‐frequency anharmonicities are included. Variational and tunneling effects are treated by canonical variational transition state theory with multidimensional small‐curvature tunneling. And, most significantly, we include multistructural effects in the rate constant calculations. Our calculations show that the catalytic effect of water vapor is not observable at 200–400 K.     

Divergent Biomimetic Total Syntheses of Ganocins A–C,Ganocochlearins C and D,and Cochlearol T

A divergent synthetic approach to six Ganoderma meroterpenoids, namely ganocins A–C, ganocochlearins C and D, and cochlearol T, has been developed for the first time. This synthetic route features a two‐phase strategy which includes early‐stage rapid construction of a common planar tricyclic intermediate followed by highly selective late‐stage transformations into various Ganoderma meroterpenoids. Key to the strategy are a bioinspired intramolecular hetero‐Diels–Alder reaction and Stahl‐type oxidative aromatization, allowing efficient formation of the common tricyclic phenol intermediate. A nucleophilic dearomatization of the phenol unit, combined with a regioselective 1,4‐reduction of the resulting dienone, enabled rapid access to ganocins B and C. Additionally, site‐selective Mukaiyama hydration, followed by an intramolecular oxa‐Michael addition/triflation cascade, served as a key strategic element in the chemical synthesis of ganocin A.     

De Novo Construction of Catenanes with Dissymmetric Cages by Space‐Discriminative Post‐Assembly Modification

Considerable efforts have been made to increase the topological complexity of mechanically interlocked molecules over the years. Three‐dimensional catenated structures composed of two or several (usually symmetrical) cages are one representative example. However, owing to the lack of an efficient universal synthetic strategy, interlocked structures made up of dissymmetric cages are relatively rare. Since the space volume of the inner cavity of an interlocked structure is smaller than that outside it, we developed a novel synthetic approach with the voluminous reductant NaBH(OAc)₃ that discriminates this space difference, and therefore selectively reduces the outer surface of a catenated dimer composed of two symmetric cages, thus yielding the corresponding catenane with dissymmetric cages. Insight into the template effect that facilitates the catenation of cages was provided by computational and experimental techniques.     

Tiara[5]arenes: Synthesis,Solid‐State Conformational Studies,Host–Guest Properties,and Application as Nonporous Adaptive Crystals

Tiara[5]arenes (T[5]s), a new class of five‐fold symmetric oligophenolic macrocycles that are not accessible from the addition of formaldehyde to phenol, were synthesized for the first time. These pillar[5]arene‐derived structures display both unique conformational freedom, differing from that of pillararenes, with a rich blend of solid‐state conformations and excellent host–guest interactions in solution. Finally we show how this novel macrocyclic scaffold can be functionalized in a variety of ways and used as functional crystalline materials to distinguish uniquely between benzene and cyclohexane.