金属纳米团簇在农药检测中的应用研究进展

农药对提高农作物质量和产量具有重要作用,然而,过量以及不合理使用农药导致的残留和污染对人类健康及环境均具有严重危害,因此对农药及其残留的检测尤为重要。金属纳米团簇（Metal nanoclusters,MNCs）作为一种新型纳米材料,具有尺寸小、稳定性高、易制备和生物相容性好等优点,在分析传感领域备受关注。MNCs在农药检测方面也展现出巨大的应用潜力。本文综述了近年来基于MNCs的检测方法以及在有机磷农药、有机氮农药和有机氯农药等常见农药检测中的研究进展,并对其在农药检测方面的发展前景进行了展望。     

原子级精确的币金属纳米团簇在光催化应用方面的研究进展

光催化技术可以直接将太阳能转化为化学能,制造化学燃料或环境友好的产品。然而,常用的光催化剂大多为具有宽能隙的半导体材料,所需光源大多在紫外区,对太阳光的利用率不高;并且电子-空穴复合率高,导致光催化反应效率低。币金属纳米团簇具有超小尺寸（<2 nm）和分立能级,能够实现电子和空穴的分离,电子结构可调,可以通过调节其电子结构进而提高其光催化性能。同时,精确的原子级组成和结构使其成为一种在原子水平上探索光催化机制的理想模型。本文报道了基于币金属纳米团簇的光催化反应的现状,包括水分解产氢、有机污染物降解和光催化氧化胺等。通过探讨调节币金属纳米团簇的光催化性能的策略,对币金属纳米团簇光催化剂的发展前景予以展望。     

液态金属Al快速凝固过程中团簇结构的形成特性

A simulation study on the formation characteristics of clusters in a large-scale liquid Al system consisting of 105 atoms has been performed by the molecular dynamics method. And a cluster-type index method（CTIM）has been used to describe the structural configurations of various clusters. The results demonstrate that the icosahedron clusters（12 0 12 0）and their combinations play the most important role in the microstructure transition. The nanoclusters（containing up to 104 atoms）have been formed by combining some middle clusters which have been formed by combining smaller basic clusters. The structures of these nano-clusters are very different from those of nano-clusters obtained by evaporation,ionic spray methods,and so on. The latter is formed by the multi-shell crystals accumulated with an atom as the center and the surrounding atoms arranged according to octahedron configuration. The center atoms of these basic clusters are bond-connected each other with the linear or twisting mode. The corners of the nano-cluster just could become the starting points of the dendrite growth in the solidification processes of liquid metals.     

荧光金属纳米团簇的制备及其在环境污染物检测中的应用研究进展

环境污染物存在难降解、易累积等问题,对人体健康和生态环境构成严重威胁。因此,实现污染物的快速、灵敏检测至关重要。金属纳米团簇(Metal nanoclusters, MNCs)因具有尺寸小、稳定性高、制备耗时短和易修饰等性质,在化学传感领域表现出良好的应用前景。MNCs作为一种新型荧光纳米材料,在污染物检测方面备受关注。本文评述了近年来MNCs在检测重金属离子、硫化物、氰化物、多硝基芳族物质、甲醛、有机农药、细菌和病毒等物质方面的研究进展,并对MNCs的发展前景进行了展望。     

金属纳米团簇强荧光研究获进展北大核心CSCD

近日,安徽大学和美国卡内基梅隆大学、匹兹堡大学合作完成的一项研究,使人类有望开发出新一代生物荧光检测与诊断试剂,为进一步了解金属纳米团簇的荧光起源提供了新思路和方法。相关成果在线发表于《德国应用化学》杂志。     

原子数精确的金属纳米团簇在电催化领域的应用研究进展

金属纳米团簇(MNCs)是由几个到数百个金属原子组成,其尺寸一般小于2nm.金属纳米团簇在许多催化反应中表现出高的催化活性和选择性,这与金属纳米团簇具有高的比表面积、较多暴露的活性原子,以及与金属纳米粒子(MNPs)不同的电子结构有关.金属纳米团簇确定的组成和结构使其成为一种新型模型催化剂,对纳米团簇的催化性能研究有利...     

液相合成金纳米团簇

作为过渡金属团簇的一种,金纳米团簇由于具有不同于其它纳米材料的特殊物化性能,在催化、光学、电学及生物技术等领域具有潜在的应用前景。本文综述了液相合成金纳米团簇的研究进展,主要包括有机膦化物和硫醇保护的金纳米团簇的合成方法与晶体结构,这将为金纳米团簇的研究者提供一定的参考。     

金属纳米团簇强荧光研究获进展

<正>近日,安徽大学和美国卡内基梅隆大学、匹兹堡大学合作完成的一项研究,使人类有望开发出新一代生物荧光检测与诊断试剂,为进一步了解金属纳米团簇的荧光起源提供了新思路和方法。相关成果在线发表于《德国应用化学》杂志。众所周知,因为有光,人们可以看到宏观世界的美妙;因为荧光,科研工作者可以看到微观世界的细胞精细结构,甚至可以在分子层面了解化学反应。     

高核Ag/S纳米团簇合成的研究进展

硫醇配体保护的高核银纳米团簇具有丰富的结构和性能, 在光致发光、 生物传感、 纳米材料等方面具有广阔的应用前景. 然而, 精确控制高核Ag/S纳米团簇的尺寸和结构面临着巨大的挑战, 构建高核Ag/S纳米团簇的可行策略也一直是人们关注的焦点. 近年来, 随着合成方法和表征技术的不断发展, 高核Ag/S纳米团簇的合成和性能研究方面均取得了显著的成就. 本文总结了含20个或以上Ag原子的Ag/S纳米团簇的合成方法(直接还原法、 阴离子模板法及配体交换法), 对部分高核Ag/S纳米团簇的结构进行了探讨, 并展望了未来研究的趋势.     

液态金属Al凝固过程中的团簇结构与幻数特性

采用分子动力学方法,对含有100000个Al原子的液态金属系统在凝固过程中团簇结构的形成特性进行了模拟研究,并采用原子团类型指数法(CTIM)来描述各种类型的团簇结构组态.研究结果显示:在液态金属Al的凝固过程中,只有与1551键型相关的二十面体原子团(12 0 12 0)及其组合形成的各种团簇结构,对微结构的演变起着关键的、决定性的作用;由不同数目、不同类型基本原子团组成的各种层次的团簇结构,都在一定的原子数区段内呈现出峰值,即幻数点;系统的幻数序列为:13(13), 19(21), 25～28(27), 31～33(29～30) ,37、39,…(括号内为液态时对应的幻数值),与Harris等人的实验结果甚为相符.本模拟研究所用的团簇结构按层次区段来研究幻数序列的方法,可为实验结果提供更为合理的模型解释.     

碳量子点的荧光发射机制

碳量子点(CQDs)一般是指粒径小于10 nm的零维碳材料,因其具有优良的光学特性而在生物成像、光学器件、生物复合材料和生物传感等领域得到广泛应用,并有望成为未来应用最广泛的一种碳材料.CQDs的光学特性受粒径、表面官能团及合成的条件(如温度、溶剂的种类和pH等)的影响,为了精准调控其光学性能以及进一步扩大其应用范围,...     

Size Effect of Graphene Quantum Dots on Photoluminescence

High-photoluminescence (PL) graphene quantum dots (GQDs) were synthesized by a simple one-pot hydrothermal process, then separated by dialysis bags of different molecular weights. Four separated GQDs of varying sizes were obtained and displayed different PL intensities. With the decreasing size of separated GQDs, the intensity of the emission peak becomes much stronger. Finally, the GQDs of the smallest size revealed the most energetic PL intensity in four separated GQDs. The PL energy of all the separated GQDs shifted slightly, supported by density functional theory calculations.     

A 200‐fold Quantum Yield Boost in the Photoluminescence of Silver‐Doped AgxAu25−x Nanoclusters: The 13 th Silver Atom Matters

The rod‐shaped Au₂₅ nanocluster possesses a low photoluminescence quantum yield (QY=0.1 %) and hence is not of practical use in bioimaging and related applications. Herein, we show that substituting silver atoms for gold in the 25‐atom matrix can drastically enhance the photoluminescence. The obtained Ag_xAu_25?x (x=1–13) nanoclusters exhibit high quantum yield (QY=40.1 %), which is in striking contrast with the normally weakly luminescent Ag_xAu_25?x species (x=1–12, QY=0.21 %). X‐ray crystallography further determines the substitution sites of Ag atoms in the Ag_xAu_25?x cluster through partial occupancy analysis, which provides further insight into the mechanism of photoluminescence enhancement.     

Partial Phosphorization: A Strategy to Improve Some Performance(s) of Thiolated Metal Nanoclusters Without Notable Reduction of Stability

Thiolates endow metal nanoclusters with stability while sometimes inhibit the catalytic activity due to the strong M−S interaction (M: metal atom). To improve the catalytic activity and keep the stability to some extent, one strategy is the partial phosphorization of thiolated metal nanoclusters. This is demonstrated by successful partial phosphorization of Au₂₃(SC₆H₁₁)₁₆ and by revealing that the products Au₂₂(SC₆H₁₁)₁₄(PPh₃)₂ and Au₂₂(SC₆H₁₁)₁₂(PPh₃)₄, with varied degree of phosphorization, both show excellent activity in the photocatalytic oxidation of thioanisole without notable reduction of stability. Furthermore, Au₂₂(SC₆H₁₁)₁₂(PPh₃)₄ exhibits better photoluminescence performance than the mother nanocluster Au₂₃(SC₆H₁₁)₁₆, indicating that partial phosphorization can also improve some other performance(s) except for the catalytic performance. The intermediates Au_22-xCu_x(SC₆H₁₁)₁₂(PPh₃)₄ (x=1, 2) in the transformation from Au₂₃(SC₆H₁₁)₁₆ (Au₂₂(SC₆H₁₁)₁₄(PPh₃)₂) to Au₂₂(SC₆H₁₁)₁₂(PPh₃)₄ were captured and identified by mass spectrometry and single crystal X-ray diffraction, which throws light on the understanding of the non-alloyed anti-galvanic reaction.     

“非保护型”金属胶体纳米簇形成机理研究

碱-乙二醇法制备的"非保护型"金属及合金纳米簇由表面吸附的溶剂分子和简单离子实现稳定化,它们被广泛用于制备高性能复相催化剂和研究复相催化剂中的尺寸、组成、载体表面基团以及修饰剂对催化性能的影响。关于此类非保护金属纳米簇的形成过程及机理的认识尚有待进一步深化。本文采用原位快速扫描X射线吸收精细结构谱(QXAFS)、原位紫外-可见(UV-Vis)吸收光谱、透射电子显微镜和动态光散射技术研究了碱-乙二醇法合成中非保护型金属胶体纳米簇的形成过程与机理。结果表明,在碱-乙二醇法合成非保护型Pt金属纳米簇的过程中,室温下即有部分Pt(IV)被还原至Pt(II)。随着反应温度的升高,OH-逐渐取代与Pt离子配位的Cl-,在Pt―Pt键形成之前,反应体系的UV-Vis吸收光谱中可观察到明显的纳米粒子的散射信号,原位QXAFS分析表明Pt纳米簇是由Pt氧化物纳米粒子还原所形成的;在Ru金属纳米簇的形成过程中,OH-首先取代了Ru Cl_3中的Cl~-,形成羟基配合物Ru(OH) _6~(3-),后者进一步缩合形成氧化钌纳米粒子,最终Ru金属纳米簇由乙二醇还原氧化钌纳米粒子形成。由于先形成了氧化物纳米粒子,后续的还原反应被限制在氧化物纳米粒子内,使最终得到的非保护型金属纳米簇具有尺寸小、分布窄的特点。本工作所获得的知识对发展高性能能源转化催化剂、精细化学合成催化剂、传感器等功能体系具有重要意义。     

Synthesis,Structure and Photoluminescence of Two Zinc Carboxylate Polymers with Different Coordination Architectures

Introduction　　Thesynthesisofmetal organicpolymershasundoubt edlybeenatopicofspecialinterestduetotheirhost guestinteractionswhichhavebeentailoredtoavarietyofindus trialprocessessuchascatalysis ,adsorptionandgassepa ration .1 5Sofar ,manyeffortshavebeendedicatedtotheexplorationofmetal organicframeworkmaterialsbuiltupfrommetallicclustersandrigidorganicbuildingblocks .Thisstrategy ,asreportedbythegroupsofRobson ,6Yaghi7 11andothers ,utilizesrigidorganiclinkersfordi rectlylinkingthemetalclusters…     

Integrated Photoresponsive Alkaline Earth Metal Coordination Networks: Synthesis,Topology, Photochromism and Photoluminescence Investigation

Photoresponsive materials are a key part of the age of smart technology that have potential in a broad range of applications. Coordination networks (CNs) are widely used due to their designability and stability. In this work, three novel alkaline earth metal coordination networks (AEM-CNs): [Mg(CMNDI)(H₂O)₂], [Ca(CMNDI)(H₂O)₂]⋅H₂O, and [Sr(CMNDI)(H₂O)(DMF)] with fsl , cds , and scn topology nets were synthetized via N,N’-bis(carboxymethyl)-1,4,5,8-naphthalenediimide (H₂CMNDI); the scn net is not found in the Reticular Chemistry Structure Resource or ToposPro. The reusable and sensitive photochromic properties of the three CNs enable them to be used as secret inks or ultraviolet detectors. In addition, the CNs also exhibited reusable photoluminescent turn-off toward the drug molecules, balsalazide disodium (Bal.) and colchicine (Col.), with good limits of detection of 0.16 and 0.70 μM. To the best of our knowledge, this is the first study of a fluorescence sensor for Bal. Thus, the AEM-CNs provide a design idea for integrated photoresponsive materials that could be further improved in the near future by further study.     

Synthesis of CdTe Quantum Dots with Tunable Photoluminescence Using Tellurium Dioxide as Tellurium Source

A simple and convenient method has been developed for synthesis of water‐soluble CdTe quantum dots (QDs) under ambient atmospheric conditions. In contrast to the traditional aqueous synthesis, green to red emitting CdTe QDs were prepared by using TeO₂ to replace Te or Al₂Te₃ as tellurium source in this method. The influences of experimental variables, including pH value, 3‐mercaptopropionic acid (MPA)/Cd and Te/Cd molar ratios, on the emission peak and photoluminescence (PL) quantum yield (QY) of the obtained CdTe QDs have been systematically investigated. Experimental results indicate that green to red emitting CdTe QDs with a maximum photoluminescence quantum yield of 35.4% can be prepared at pH 11.3 and n_(Cd):n_(Te):n_(MPA)=1:0.1:1.7.     

基于蛋白和多肽为模板的贵金属纳米簇合成研究

贵金属(Au, Ag, Pt等)纳米簇通常指的是由几个到约一百个原子组成的分子聚集体, 具有生物相容性好、超小尺寸(<2 nm)以及优异的物理化学性质, 尤其是能发出较强荧光等特点引起了人们的广泛关注. 目前多种贵金属纳米簇的合成方法已相继被报道, 且已应用于生物荧光成像、电化学发光、生物传感器以及细胞标记等多个领域. 本文共分为五部分, 首先重点介绍近几年兴起的以蛋白和多肽为模板来合成纳米簇的方法及优点, 并随后总结列举了文献中所采用的蛋白以及自主设计的多肽组分序列的类别, 随后探索了蛋白和多肽中的特定氨基酸与合成的贵金属纳米簇的荧光波长、量子产率、粒径之间的联系. 本文最后总结阐述了蛋白和多肽为模板成功合成贵金属纳米簇的先决条件并对其生物医学应用前景进行了展望.