Ir和IrPd催化剂的合成及结构调控对其甲醇氧化性能的影响

以三嵌段共聚物P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷,PEO₂₀-PPO₇₀-PEO₂₀)为还原剂和保护剂,比较了水热法和溶剂热法对纯Ir和IrPd合金催化剂合成及其电催化氧化甲醇(MOR)性能的影响。对于纯Ir催化剂,在相同条件下,溶剂热法能更好地促进Ir前驱体的还原。对于IrPd合金催化剂,溶剂热法可制得表面富含Ir但MOR活性较低的核壳结构产物(IrPd-S)。水热反应得到的不同原子比(IrPd、Ir₂Pd、IrPd₂)的产物粒径更小,元素分布更均匀。其中比例为1∶1的IrPd (IrPd-H)催化剂的MOR电催化活性最高。上述结果表明,通过调节溶剂类型以及P123的结构诱导作用,可以有效地调节纯Ir和IrPd合金催化剂的结构、表面组成和电催化活性。     

Ir和IrPd催化剂的合成及结构调控对其甲醇氧化性能的影响

以三嵌段共聚物P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷,PEO₂₀-PPO₇₀-PEO₂₀)为还原剂和保护剂,比较了水热法和溶剂热法对纯Ir和IrPd合金催化剂合成及其电催化氧化甲醇(MOR)性能的影响。对于纯Ir催化剂,在相同条件下,溶剂热法能更好地促进Ir前驱体的还原。对于IrPd合金催化剂,溶剂热法可制得表面富含Ir但MOR活性较低的核壳结构产物(IrPd-S)。水热反应得到的不同原子比(IrPd、Ir₂Pd、IrPd₂)的产物粒径更小,元素分布更均匀。其中比例为1∶1的IrPd (IrPd-H)催化剂的MOR电催化活性最高。上述结果表明,通过调节溶剂类型以及P123的结构诱导作用,可以有效地调节纯Ir和IrPd合金催化剂的结构、表面组成和电催化活性。     

基于小分子化学反应工具构建CRISPR-Cas9功能调控体系的研究进展

CRISPR技术是目前基因编辑领域的一大研究热点,已在疾病治疗、作物改良等领域得到广泛的应用,CRISPR-Cas9系统是其中研究最为深入的一种类型.如何降低Cas9/sgRNA复合物在细胞内作用的脱靶性是CRISPR-Cas9技术发展面临的主要挑战之一.利用光或活性小分子诱发的小分子化学反应工具构建CRISPRCas9功能调控体系,通过对sgRNA, Cas9或Cas9/sgRNA复合物的功能进行调控,可以在细胞乃至活体水平上一定程度实现对CRISPR-Cas9作用的时间或空间特异性的操纵,大大降低非特异性基因编辑作用发生的概率,同时小分子对原体系的干扰较小,因此小分子化学反应逐渐成为操纵CRISPR-Cas9体系的一种重要的研究工具.本文总结和介绍了小分子反应工具用于CRISPR-Cas9功能调控系统构建的主要研究进展,并对其未来的发展进行了展望.     

酪氨酸衍生物调控酶催化路径可控合成功能黑色素

利用酶催化自组装将生物小分子构筑成具有独特功能的生物大分子聚合物是制备功能生物材料极具前景的新策略,然而其挑战在于如何在底物层面调控生物大分子的结构和功能.以从酪氨酸构筑黑色素为例,通过底物结构的简单衍生化,实现了对酶催化自组装过程中关键聚合位点的控制,得到一系列尺寸、形貌各异的黑色素产物.进一步表征了各黑色素产物的光热转换性能,在细胞层次验证了结构修饰的黑色素用于光热材料的潜力.揭示了通过改变底物核心基团周边化学结构调控酶催化路径,进一步调控黑色素产物性质及功能的可行性,为构筑新型功能黑色素材料提供了新思路,同时对揭示生物大分子结构与生物功能的关系提供了有益启示.     

无机纳米晶的形貌调控及生长机理研究

形貌及尺寸规整可控的纳米晶体的合成是目前十分引人注目的纳米材料研究领域．制备合成中的形貌调控及其功能化是这些纳米材料能够得到应用的关键问题．研究者们希望在纳米晶的任一阶段均能实现控制并在期望的阶段停止,从而得到尺寸、形态、结构及组成确定的纳米晶体．本文综述了近年来无机纳米晶体的典型合成路径,深入探讨了纳米晶在成核、生长及熟化阶段的控制原理,研究了液相合成纳米材料过程中晶体结构与生长行为的相关性问题,并总结了几类具有代表性的低维、多维纳米晶体的形成规律和生长机理．探索纳米粒子的调控合成对于纳米材料的规模化生产及应用具有重要的理论价值和指导意义．     

金属离子对金属蛋白结构与功能的调控

生命金属在生命过程中以不同的化学方式发挥着重要的作用。质膜、细胞器膜等使不同的生命金属在生物体系中有着不同的隔室化分布,相应的金属蛋白或金属伴侣蛋白在维持金属离子内稳态(homeostasis)中起着关键作用。生命体系中广泛存在着具有两个以上金属离子结合部位的金属蛋白。在确定的生理微环境下,由于金属离子结合热力学性质的不等价,该类金属蛋白的生物学功能取决于所结合金属离子的种类及多少。本文以伴刀豆球蛋白A、铜/锌超氧化物歧化酶、中心蛋白、锌指蛋白为例,介绍了金属离子在调控金属蛋白生物学功能中的作用。因此,深入研究金属离子与金属蛋白结合的热力学性质对于理解生命过程的无机化学基础具有重要意义。     

生物矿化、仿生合成与形貌调控

介绍了生物矿化材料的种类、结构、特点、形貌调控原则以及基于微生物、蛋白质、多肽、氨基酸和核酸等晶体调节剂的生物矿化材料的合成,总结了近年来生物矿化和彷生合成领域的研究进展.     

铁基费托合成催化剂相变调控及反应性能

在Fe基模型催化剂上,通过先深度还原后控制碳化的方法实现了物相结构的调控.采用X射线衍射、穆斯堡尔谱、程序升温脱附技术和激光拉曼光谱等方法表征了催化剂还原和反应前后的物化性质,并在固定床反应器中考察了不同条件活化后催化剂上费托反应性能.结果表明,H₂还原后的催化剂主要由α-Fe相组成,且随着还原温度的提高,α-Fe相的致密程度增加,平均晶粒尺寸增加,稳定性提高;再采用乙烯对H₂还原后催化剂进行碳化,可有效控制α-Fe的碳化速度,使碳化过程主要发生在Fe晶粒表层,同时改变了催化剂在反应过程中的物相变化,乃至其催化性能.与纯H₂或合成气气氛活化的催化剂相比,采用先H₂还原后乙烯碳化的预处理方法能够明显提高催化剂的活性和稳定性.     

人工调控细胞表面受体聚集状态及功能

从利用物理刺激和生物大分子诱导两个方面综述了人工调控细胞表面受体聚集状态的策略.前者是利用相应的纳米材料在光、磁场、温度等物理刺激作用下实现人工调控受体聚集;后者则利用包括蛋白/多肽类分子、核酸在内的生物分子的自组装对其靶向识别的受体进行人工调控.系统介绍了相关研究领域取得的最新进展,并阐述和展望了该领域现存的挑战和发展方向.     

ZIF-8纳米颗粒的粒径调控及生物医学应用

沸石咪唑酯骨架材料(Zeolitic Imidazolate Framework-8, ZIF-8)是由锌离子与2-甲基咪唑配位自组装成的多孔结晶材料,其比表面积大、孔隙率高、合成便捷、尺寸可控,在功能物质的包封与输运中具有突出的优势。与此同时,这类材料更具备优异的生物相容性,且其结构在生理条件下具有良好的稳定性,而在酸性条件下解体,对于与恶性肿瘤等多种疾病相关的弱酸性环境具有响应性,是控制药物运输与释放的理想载体,因而在生物医学上有很大的应用潜力。事实上,ZIF-8不但能高效负载阿霉素、5-氟尿嘧啶等小分子化疗药物,而且可以充当抗体、核酸等生物大分子的保护层。ZIF-8的粒径等性能对于相应的生物医学应用非常关键,而如何实现ZIF-8功能性的精准调控将是实现其生物医学应用的重要挑战,基于此,本文就ZIF-8的制备机理、性能调控及其生物医学应用进行综述和展望。     

Combinatorial Synthesis of Small Organic Molecules

Combinatorial synthesis has developed within a few years from a laboratory curiosity to a method that is taken seriously in drug research. Rapid progress in molecular biology and the resulting ability to determine the activity of new substances extremely efficiently have led to a change in paradigm for the synthesis of test compounds: in addition to the conventional procedure of synthesizing one substance after another, new methods allowing simultaneous creation of many structurally defined substances are becoming increasingly important. A characteristic of combinatorial synthesis is that a reaction is performed with many synthetic building blocks at once—in parallel or in a mixture— rather than with just one building block. All possible combinations are formed in each step, so that a large number of products, a so-called library, is obtained from only a few reactants. Several methods have been developed for combinatorial synthesis of small organic molecules, based on research into peptide library synthesis: single substances are produced by highly automated parallel syntheses, and special techniques enable targeted synthesis of mixtures with defined components. Many structures can be obtained by combinatorial synthesis, and the size of the libraries created ranges from a few individual compounds to many thousand substances in mixtures. This article gives an overview of the combinatorial syntheses of small organic molecules reported to date, performed both in solution and on a solid support. In addition, different techniques for identification of active compounds in mixtures are presented, together with ways to automate syntheses and process the large amounts of data produced. An overview of pionering companies active in this area is also given. The final outlook attempts to predict the future development of this exponentially growing area and the influence of this new thinking in other areas of chemistry.     

镁的正常代谢及其调节

镁是一种人体必需微量元素，对人体健康有重要意义。镁的代谢受肾脏、消化道及内分泌多种因素调节，其调节机制尚未完全清楚。     

Design,Synthesis, and Evaluation of Bioactive Small Molecules

Collaborative research projects between chemists, biologists, and medical scientists have inevitably produced many useful drugs, biosensors, and medical instrumentation. Organic chemistry lies at the heart of drug discovery and development. The current range of organic synthetic methodologies allows for the construction of unlimited libraries of small organic molecules for drug screening. In translational research projects, we have focused on the discovery of lead compounds for three major diseases: Alzheimer's disease (AD), breast cancer, and viral infections. In the AD project, we have taken a rational‐design approach and synthesized a new class of tricyclic pyrone (TP) compounds that preserve memory and motor functions in amyloid precursor protein (APP)/presenilin‐1 (PS1) mice. TPs could protect neuronal death through several possible mechanisms, including their ability to inhibit the formation of both intraneuronal and extracellular amyloid β (Aβ) aggregates, to increase cholesterol efflux, to restore axonal trafficking, and to enhance long‐term potentiation (LTP) and restored LTP following treatment with Aβ oligomers. We have also synthesized a new class of gap‐junction enhancers, based on substituted quinolines, that possess potent inhibitory activities against breast‐cancer cells in vitro and in vivo. Although various antiviral drugs are available, the emergence of viral resistance to existing antiviral drugs and various understudied viral infections, such as norovirus and rotavirus, emphasizes the demand for the development of new antiviral agents against such infections and others. Our laboratories have undertaken these projects for the discovery of new antiviral inhibitors. The discussion of these aforementioned projects may shed light on the future development of drug candidates in the fields of AD, cancer, and viral infections.     

新型非共价键构象锁定型小分子的合成及性能研究

以2,5-二溴烷氧基苯为起始原料,设计并合成了以烷氧基取代苯环为核,双氰基茚满二酮为端基,噻吩或并噻吩为π桥的两个新型非共价键构象锁定型有机小分子PTIC和PTTIC,其结构和性能经¹H NMR, ¹³CNMR, UV,CV,DSC和GIWAXS表征。结果表明：在分子内非共价键作用力作用下,PTIC和PTTIC均表现出良好的共平面性和结晶性。      

The Synthesis and Optoelectronic Applications for Tellurophene-Based Small Molecules and Polymers

Tellurophene-based small molecules and polymers have received great attentions owing to their applications in thin-film transistors, solar cells, and sensors. This article reviews the current progress of the synthesis and applications of tellurophene-based small molecules and polymers. The physicochemical properties and optoelectronic applications of tellurophene-based materials are summarized and discussed. In the end, the challenges and outlook of tellurophene-based materials are presented.     

Absolute Configuration of Small Molecules by Co-Crystallization

The most reliable method to determine the absolute configuration of chiral molecules is X-ray crystallography, but small molecules can be difficult to crystallize. We report rapid co-crystallization of tetraaryladamantanes with small molecules as different as n-decane to nicotine to produce crystals for X-ray analysis and the assignment of absolute configuration when the molecules are chiral. A screen of 52 diverse compounds gave inclusion in co-crystals for 88 % of all cases and a high-resolution structure in 77 % of cases. Furthermore, starting from three milligrams of analyte, a combination of NMR spectroscopy and X-ray crystallography produced a full structure in less than three days using an adamantane crystallization chaperone that encapsulates the analyte at room temperature.     

Activation of Small Molecules by Phosphorus Biradicaloids

The reactivity of biradicaloid [P(μ‐NTer)]₂ was employed to activate small molecules bearing single, double, and triple bonds. Addition of chalcogens (O₂, S₈, Se_x and Te_x) led to the formation of dichalcogen‐bridged P₂N₂ heterocycles, except from the reaction with molecular oxygen, which gave a P₂N₂ ring featuring a dicoordinated P^III and a four‐coordinated P^V center. In formal [2πe+2πe] addition reactions, small unsaturated compounds such as ethylene, acetylene, acetone, acetonitrile, tolane, diphenylcarbodiimide, and bis(trimethylsilyl)sulfurdiimide are readily added to the P₂N₂ heterocycle of the biradicaloid [P(μ‐NTer)]₂, yielding novel heteroatom cage compounds. The synthesis, reactivity, and bonding of the biradicaloid [P(μ‐NTer)]₂ were studied in detail as well as the synthesis, properties, and structural features of all addition products.     

基于不同刺激源的刺激响应聚合物体系的构建

刺激响应聚合物是一类具有"智能"行为的大分子体系. 它可以接收外部环境的刺激信号, 如pH值、 光、 温度、 电压、 氧化还原剂和气体等, 使自身大分子结构或状态发生较大改变, 从而影响其物理化学性质, 进而体现出相应的功能. 大量的研究结果表明, 刺激响应聚合物在纳米材料科学、 生命科学及临床医学领域中有着广泛的应用前景. 本文主要介绍了我们课题组在基于不同刺激源的刺激响应性大分子体系研究方面的一些进展.