超分子凝胶可视化选择性识别有机小分子的研究进展

近年来,超分子凝胶作为一类非常重要的软物质材料而受到广泛关注,当前研究面临的最大问题之一是智能响应性,而智能响应性凝胶材料发展的一个重要研究方向是可视化选择性识别有机小分子。本文从有机小分子的类型(手性分子、位置异构体和氨基酸等)出发,较系统地综述了可视化选择性识别有机小分子的超分子凝胶的研究进展情况,并对该研究领域作了简单展望。     

环境响应的智能小分子有机凝胶材料

小分子有机凝胶(low molecule organogel,LMOG)是近年来逐渐发展起来的一类新型自组装材料,随着研究的深入,LMOG的功能化特别是对环境有智能响应的凝胶体系引起人们极大的研究兴趣。本文综述了4类智能响应的凝胶体系的研究进展,即: 光响应小分子凝胶体系,主要是凝胶因子内含有偶氮苯、二芳乙烯等光致变色基团;电化学响应小分子凝胶体系,主要是凝胶因子内含有四硫富瓦烯等电化学响应基团;离子(分子)响应的小分子凝胶体系,通过凝胶和客体离子(分子)间通过电荷转移或结构形变等形式实现响应;超声波响应小分子凝胶体系,在超声波外力的存在下,使分子结构以有利于形成分子间氢键的形式存在,从而形成稳定凝胶。     

具有选择性胶凝能力的小分子胶凝剂研究进展

不相溶混合溶剂的选择性胶凝对于溶剂纯化和分离,特别是溢油处理和水体净化具有十分重要的意义。 具有选择性胶凝能力的胶凝剂可以是高分子、微纳米颗粒和小分子胶凝剂。 然而,相对于高分子和微纳米颗粒材料,以小分子化合物为胶凝剂的凝胶往往具有凝胶 溶胶相变可逆性,这种可逆性无疑会对凝胶体系的实际应用带来额外的好处。 基于这些考虑,本文按照胶凝剂分子的结构,分类介绍此类小分子胶凝剂研究进展,并展望了相关研究的前景和可能应用。     

基于β-环糊精的有机小分子凝胶

环糊精是直链淀粉在环糊精葡萄糖基转移酶作用下生成的含有7个D-吡喃葡萄糖单元的环状低聚糖,具有斜截锥形空间立体结构,腔内疏水,腔外亲水。β-环糊精以其低廉的价格、良好的水溶性和生物相容性,在超分子化学领域得到广泛的应用。β-环糊精可用于凝胶的构筑,通常的方法是将β-环糊精接枝到高分子链上,再以得到的高分子链为凝胶因子构筑高分子凝胶。虽然基于β-环糊精的高分子凝胶得到了广泛的关注和研究,但是,直接以β-环糊精为凝胶因子构筑的有机小分子凝胶却鲜有报道。2010年,本课题组首次报道了一种基于β-环糊精和二苯胺的热致有机凝胶。此后,本课题组在β-环糊精有机小分子凝胶领域做了大量的研究工作。本文在实验室研究工作的基础上,首先介绍了β-环糊精有机小分子凝胶的分类和不同因素对凝胶形成的影响,然后深入探讨了β-环糊精有机小分子凝胶的形成机理,系统介绍了β-环糊精有机小分子凝胶的刺激响应性以及在药物载运领域的应用,最后,对β-环糊精有机小分子凝胶的发展前景进行了展望。     

路易斯碱有机小分子催化亚胺的不对称还原研究进展

近年来,路易斯碱有机小分子催化的亚胺不对称还原反应,因氢源廉价和后处理简单等优点而受到关注.分别介绍了甲酰胺类、吡啶酰胺类、亚磺酰胺类、非酰胺类以及负载型路易斯碱有机小分子催化剂在亚胺不对称还原中的应用,并且对催化剂的结构特点、催化活性及催化机理等方面展开了论述.     

石墨烯基水凝胶的研究进展

石墨烯具有独特的导电、导热和力学性能,既能够自组装为电化学性能优良的石墨烯水凝胶,又可以与小分子和聚合物进行复合制备多功能性复合水凝胶,大幅度地拓展了传统水凝胶的应用范围。本文主要分为四部分来综述近些年来石墨烯基水凝胶的研究进展。第一部分简要介绍了石墨烯的研究背景和石墨烯基水凝胶的研究意义。第二部分主要根据石墨烯基水凝胶的组成将其分为石墨烯水凝胶、石墨烯/小分子和石墨烯/聚合物复合水凝胶三类,分别介绍了它们的制备方法、形成机理和凝胶性能。其中,对石墨烯/小分子复合水凝胶的介绍以石墨烯基超分子水凝胶为主,而对石墨烯/聚合物复合水凝胶的介绍以智能型水凝胶为主。第三部分主要介绍了石墨烯基水凝胶在超级电容器、水处理、控释药物、微流体开关、催化剂载体等方面的应用和发展。最后,对该领域所面临的挑战进行了总结和展望。     

选择性固相微萃取涂层的研究进展

固相微萃取装置的核心部分是它的涂层,涂层的种类和厚度是影响分析灵敏度和选择性的最重要因素。具选择性的涂层可增强固相微萃取的分离能力,扩展它的应用范围。本文介绍了固相微萃取的类型,综述了近年来选择性固相微萃取涂层的研究进展,包括溶胶-凝胶涂层、限进介质涂层、分子印迹涂层等涂层的研制及应用。     

脂肪酰谷氨酸与小分子有机凝胶

研究了脂肪酰谷氨酸作为凝胶因子在不同有机溶剂中的成胶性能。结果表明,小分子有机凝胶的形成及其稳定性与有机溶剂种类、凝胶因子浓度和凝胶因子中碳链长度密切相关。FT-IR表明,凝胶因子在有机溶剂中是通过氢键等非共价力相互作用而聚集、自我组装形成凝胶。利用光学显微镜观察发现,凝胶因子在不同有机溶剂中形成凝胶的微观结构不同。     

有机凝胶自组装模板法制备纳米材料

利用溶胶一凝胶聚合过程人工模拟生物矿化进程的技术,已经融人无机材料和超分子有机化学的研究领域.小分子有机凝胶因子在溶剂中发牛自组装,形成多种形态的有机凝胶超分子结构,以其为模板,经过溶胶一凝胶过程,可以诱导转录形成各种形态的纳米材料.本文介绍了利用有机凝胶因子自组装结构为模板制备形态可控无机材料的研究进展及模板结构诱导转录的两种可能机制.     

基于低分子量凝胶因子的超分子水凝胶：从结构到功能*

基于低分子量凝胶因子的超分子水凝胶由于其良好的刺激相应性及生物相容性,在智能凝胶、组织工程等方面有广泛的应用前景。而凝胶因子的设计制备与凝胶机理的研究已成为其发展的关键,本文在介绍超分子凝胶的基本概念的基础上,综述了超分子水凝胶近期的研究进展,主要介绍了凝胶因子的种类及超分子水凝胶的应用,并对超分子凝胶领域的国内外研究现状及前景进行了评述。     

国内光催化研究进展简述

分1975~1985, 1985~1995和1995~2012三个时期简要介绍了国内光催化研究进展, 主要侧重于光催化材料及其改性、应用和反应机理方面的研究进展, 并指出了当前光催化领域存在的一些重要问题和未来的发展趋势, 涉及到光解水、CO₂还原、环境净化和选择性有机合成等方面.     

青蒿素研究进展

青蒿素是目前治疗疟疾的特效药。本文对自青蒿素发现以来的最新研究进展进行了比较详尽的综述。内容包括: 青蒿素的发现及历史, 青蒿素的来源, 青蒿素的全合成,青蒿素的生物合成, 青蒿素衍生物以及植物组织培养生产青蒿素。     

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.     

Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat

The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (As_i). In order to document the methylation process in humans, the kinetics of As_i, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of As_i. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As₂O₃) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of As_i metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of As_i uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.     

Gemini表面活性剂合成进展

系统总结了近百种Gemini表面活性剂的合成路线和方法,并且按照其结构特点分门别类地进行比较和归纳,对今后Gemini表面活性剂的合成发展方向提出了一些看法,这对促进此类新颖表面活性剂的工业化进程将具有指导意义。     

Recent Advances in Analytical Methodology for in vivo Electrochemistry in Mammals

Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.     

乙基香兰素研究前景

报导了近几十年来国内外关于乙基香兰素的研究进展与动态,并简单介绍了本文作者在该方面所取得的研究成果,参考文献33篇。     

Trends in education in analytical chemistry

Summary At the session of the WPAC of Fechem on education in analytical chemistry it was concluded that it is now essential to include chemometrics and basic knowledge of computers in all courses on analytical chemistry.

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Tendenzen in der analytisch-chemischen Ausbildung

Zusammenfassung Bei einer Tagung der WPAC über die Lehre auf dem Gebiet der analytischen Chemie wurde bei der Betrachtung neuer Aspekte festgestellt, daß vor allem Chemometrie und Grundkenntnisse in Computertechnik in die Ausbildung aufgenommen werden sollten.

     

钙与人体及临床

钙是宏量元素，是人体中含量较高的元素之一，体内99％的钙构成骨骼和牙齿以及维持骨骼结构，1％的钙调节人体重要生理功能。钙的含量过高或过低都与许多疾病有关，只有保持一种平衡状态，才能使机体处于正常环境。     

AGET ATRP in the Presence of Air in Miniemulsion and in Bulk

Summary: The recently developed initiation system, activators generated by electron transfer (AGET), is used in atom transfer radical polymerization (ATRP) in the presence of a limited amount of air. Ascorbic acid and tin(II ) 2‐ethylhexanoate are used as reducing agents in miniemulsion and bulk, respectively. An excess of reducing agent consumes the oxygen present in the system and, therefore, provides a deoxygenated environment for ATRP. ATRP of butyl acrylate is successfully carried out in miniemulsion and in the presence of air. During polymerization the radical concentration remains constant. The polymerization reaches over 60% monomer conversion after 6 h, which results in polymers with a predetermined molecular weight = 14 000 g · mol⁻¹ and a low polydispersity ( = 1.23). AGET ATRP of styrene is also successful in bulk in the presence of air, as evidenced by linear semi‐logarithmic kinetics, which leads to polystyrene with an of 13 400 g · mol⁻¹ and a low polydispersity index ( = 1.14).

Appearance of miniemulsion before and after the reducing agent ascorbic acid was added (left); and GPC traces representing molecular weights during the AGET ATRP of BA in miniemulsion in the presence of air (right).