EXAFS研究合成甲醇催化剂Cu／ZnO／MxOy

有关CO。＋H。合成甲醇催化剂的研究已有许多报道［‘－’j，但目前对活性中心及反应机理的认识仍不～致，其中对活性中心的看法归纳起来有3种：（1）Cll为活性中心“‘；（2）Cll”为活性中心［’j；（3）Cll－CtJ”为活性中心［‘1．研究发现，第三组分（如AI刀。）的加入可防止Cu粒子的烧结［’］，使Cu产生无序及缺陷结构，有利于CO。的吸附、活化［‘j及起到高分散Cu／Zno的稳定剂的作用［’j．由于三组分催化剂结构的多相性和准非晶态性，通常的XRD方法难以明确了解其结构，而EXAFS方法对研究局部有序结构特别有效．本文以Z…     

纳米氮化镁的合成

在制备高硬度、高热导、耐磨、耐腐蚀、耐高温的新兴陶瓷材料氧化硼、氮化硅的固相反应中，氮化镁是不可缺少的烧结助剂［‘，’j．同时，氮化镁还可用于制备发泡合金和回收核废料等领域．目前氮化镁的制备方法有：镁粉直接与氮气反应法［‘，‘1、镁在氮等离子流中与氮反应法＊‘、在氮气气氛下镁线圈爆炸法‘’‘和低压化学气相沉积法［’j．在上述方法中，有些方法需要复杂和昂贵的设备．有些方法得到氮化镁的产率较低．镁粉直接与氮气反应是具有工业生产价值的方法一然而，这种方法需要SOO”C到gOO”C的高温．我们曾经报道过利用温和…     

天然产物(±)-Litsenolide C_2的立体选择性合成

含3一烷叉基一4，5一二氢一4一羟基一5一甲基一2－（3H）一吠哺酮（简称AHF）结构的天然产物广泛存在于律科植物中［‘j，该类化合物往往具有高细胞毒性和抗肿瘤等生物活性［’－’1．Litseno－lideC是1972年Ishii等［‘j首次从樟科植物中分离得到的一种AHF，其结构为3一十四烷叉基一4，5一二氢一个羟基一5一甲基一2－（3H）一块哺酮，根据其烷又基构型不同又可分为：（3Z，4a，sp）－LitsenolideC；和（3E，4a，sg）－LitsenolideC。（1）．目前大多数合成LitsenolideC的方法立体选择性较差［’－’j，反应产物多为两种异构体的混…     

O／W微乳液中聚邻甲苯胺超微粒子的制备

聚邻甲苯胺具有较高的电导率、较好的贮存电荷的能力和良好的环境稳定性，因而具有较大的应用价值［’－‘j，其合成方法主要有电化学合成法和化学合成法［‘·’J．化学会成法所得聚邻甲苯肢的粒子一般大于100urn．近年来，以表面活性剂聚集体微乳液、溶致液晶为介质，制备超微粒子材料已为人们所关注「’－’］．以微乳液为介质进行聚合反应亦引起重视，但大部分微乳液聚合都是在四组分微乳液（表面活性剂、助表面活性剂、单体和水）中进行‘”·“‘．近年来，某些油溶性单体已成功地在无助表面活性剂的三组分微乳液中聚合［‘’·‘’1…     

二(2,6-二叔丁基-4-个甲基苯氧基)钐催化丙交酯开环聚合

聚丙交酯（PLA）可以生物降解，产物无毒，可用于外科手术的缝合线、人造器官以及药物缓释等方面，因此引起了人们的广泛注意．丙交酯的开环聚合是合成聚丙交酯的一种方便方法，所用的催化剂主要是主族及副族金属的配合物，如双金属氧桥配合物［‘j，烷基金属有机化合物［‘j，异丙氧基铝［’‘以及叶琳铝「“等．最近，关于三价烷氧基稀土化合物作为单组份催化剂催化丙交酯开环聚会已有报道［’·’‘．我们发现两价芳氧基稀土化合物（ArO）。Sin（THF）。（ArO一2，已二叔丁基一个甲基苯氧基）也可以有效地催化丙文酯的开环聚合．本…     

1,4,7,10-四氮杂环十二院的合成研究

多氮杂环化合物及其衍生物近年来愈来愈显示出其重要而广泛的用途,譬如：可作为人体内结石的清除药物［‘·’j,作为MnSOD的模拟物可抑制心肌缺血性再灌注引起的损伤［’j,且具有抗爱滋病活性等;尤其是在制造磁共振成像（MRI）、X射线CT、超声成像等医学影像技术的造影剂以及恶性肿瘤的放射性治疗药物方面［‘－’‘,多氨杂环烷烃特别是1,4,7,10一四氮染环十二烷（Cyclen,环楞胺）及其衍生物显示出极其重要的应用价值．多氨杂环烷烃及其衍生物可因具体情况有不同的合成方法,环楞胺最初由乙二胶二乙酸氯与乙二胺在高度稀释条…     

4—苯甲酰氧基苯甲酸液晶性的研究

关于个苯甲酸氧基苯甲酸（BBA）的合成虽已有报道［‘j，但其双分子缔合物具有液晶性则属本文作者首次发现．一般认为在有机分子结构中引人不对称性及柔性基团对其液晶性的形成十分重要“‘．在不具备这两个条件时，当分子的长径比达到一定值（约l／d＞4）时也可能出现液晶性，但实例不多，且一般t。。很高．如聚合度为5的聚苯t。。一388”C［’j，而且难溶．这给此类液晶化合物的研究带来很大不便．BBA以双分子缔合物（BBA）。形式存在，结构对称，亦无柔性基团，但却具有液晶性，其t。。为230C．BBA与个乙酸氧基苯甲酸形成的低共熔…     

可溶性醌胺聚合物的合成

酿胺聚合物（PAQ）是一类新型聚合物，适用于配制防水、防锈涂料，对金属有很大的亲和性［‘j．但溶解性较差［‘j．本文从分子设计出发，将一St一O一键、不对称多烷基取代脂环引人聚合物主链及侧基，增大PAQ分子内旋转自由度等提高其溶解度，合成了6种PAQ．对苯配（PBQ）按文献［3」制备，mP115～116’C；a，。二氨基丙基聚甲基硅氧烷（St—O重复次数n一8，胺值388，日本东丽化学公司）；异佛尔酮二胶（IPDA，AR，日本东京化成工业株式会社）；a，。一二氨基乙氧基聚甲基硅氧烷（St－O重复次数n二7），二缩三（1，2一丙二醇）双…     

苯基(苯乙炔基)对甲苯磺酸碘(Ⅲ)的应用──5-烃基-5-苯乙炔基丙二酸亚异丙酯的合成

近年来，随着元素周期表中第VA，VIA族元素有机化合物在合成中得到了广泛的应用，激起人们对有机高价碘化物在合成中应用的兴趣［’－‘j．苯基（快基）碘盐（1）是具有多个亲电中心的化合物，在不同亲核试剂的作用下，分子中有3个部位可受到进攻［‘”j．由于通常的炔基卤化物对许多条核试剂的反应比较惰性，或者产物较为复杂，在合成上的应用受到限制．而化合物1作为快基的阳离子等效体的反应在会成上则很有价值＊，。‘．5一烃基丙二酸亚异丙酯在有机合成中是具有多种反应性能的试剂，同时又是许多热解反应的有效前体．至今，有关5一取…     

羟丙基-β-环糊精的取代度和取代位置对毛细管电泳手性药物分离的影响

研究手性化合物的分离分析方法是当今国际分析化学领域研究的热点．毛细管电泳（CE）手性分离具有高效、快速、低耗等特点，近年来已取得很大进展［‘j．环糊精（CD）及其衍生物是CE手性分离使用最多的手性选择剂，其手性分离机理是基于手性化合物（客体）的2个对映体与环糊精分子（主体）形成的包合物的稳定常数不同，而这种差别主要取决于主客体分子之间的匹配性．因此，CD及其衍生物的分子结构，包括CD衍生物的取代度和取代位，置，对手性识别有很大影响．目前，有关CD及其衍生物作为手性选择剂的CE手性分离报道较多“‘，研究的主…     

Sequential electrochemical oxidation and site-selective growth of nanoparticles onto AFM probes

In this work, we reported an approach for the site-selective growth of nanoparticle onto the tip apex of an atomic force microscopy (AFM) probe. The silicon AFM probe was first coated with a self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) through a chemical vapor deposition (CVD) method. Subsequently, COOH groups were selectively generated at the tip apex of silicon AFM probes by applying an appropriate bias voltage between the tip and a flat gold electrode. The transformation of methyl to carboxylic groups at the tip apex of the AFM probe was investigated through measuring the capillary force before and after electrochemical oxidation. To prepare the nanoparticle terminated AFM probe, the oxidized AFM probe was then immersed in an aqueous solution containing positive metal ions, for example, Ag+, to bind positive metal ions to the oxidized area (COOH terminated area), followed by chemical reduction with aqueous NaBH 4 and further development (if desired) to give a metal nanoparticle-modified AFM probe. The formation of a metal nanoparticle at the tip apex of the AFM probe was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA).     

A novel system for measurement of types and densities of sulfur crosslinks of a filled rubber vulcanizate

A novel system for measuring the crosslink densities of mono-, di- and polysulfides of a filled rubber vulcanizate was developed. The system included pre-swelling, cleavage of sulfur crosslinks by a chemical probe using thiol/n-hexylamine instead of thiol/piperidine, and two step swelling. A sample cage made of stainless steel mesh was used to measure multiple samples at the same time and to reduce experimental errors. The organic materials-extracted sample was pre-swollen in toluene to introduce the probe chemicals more rapidly and homogeneously into the whole network. Polysulfidic crosslinkages were cleaved by a chemical probe of propane-2-thiol/n-hexylamine in toluene, while di- and polysulfidic crosslinkages were dissociated by a chemical probe of n-hexanethiol/n-hexylamine in toluene. The experimental errors were lower than 2%. By using cubic apparent crosslink density, fractions of the crosslink types of an unknown rubber vulcanizate could be estimated even although the filler content and rubber composition are not analyzed.     

一种基于协同效应的肼荧光探针及其在细胞成像中的应用

开发了一种基于协同效应的新型肼荧光探针.通过在发色团上引入两种不同的识别位点,双识别位点的协同效应使得该探针对肼具有良好的专一性和灵敏度,检测限可达0.05~10.0μmol·L^-1.此外,该探针还可用于细胞(Bt-474)中肼的检测.     

倏逝波光纤免疫传感器探头的修饰及表征

光纤探头上修饰生物识别分子是倏逝波光纤免疫传感器实现目标物检测的关键步骤. 以微囊藻毒素-LR (microcystin-LR, MC-LR)为例, 采用先将小分子半抗原MC-LR与经戊二醛活化的惰性蛋白(OVA)反应生成复合物MC-LR-OVA, 然后将该复合物通过双功能试剂连接到硅烷化后的光纤探头表面, 并采用XPS和倏逝波全光纤免疫传感器对其修饰效果进行表征. 结果表明, 修饰后探头表面化学元素组成随不同修饰步骤发生了显著的变化, MC-LR-OVA被共价键合到探头表面上. 探头对MC-LR抗体表现出强烈的特异性响应, 而对其它抗体蛋白的非特异性吸附很弱, 并且具有良好的再生性能. 因此, 该修饰方案适用于环境小分子污染物的检测.     

一种含光亲和标记异戊烯侧链探针的合成与初步表征

经5步反应、以9%的总收率合成了一种含生物素修饰和光亲和标记的异戊烯侧链功能探针分子, 初步考察了反应条件下该探针分子与Saccharomyces cerevisiae AS 2.399粗蛋白的相互作用; 生物素印迹分析结果表明, 酵母中多种蛋白被探针分子修饰, 为进一步开展化学蛋白组学研究奠定了基础.     

Combining transmission geometry laser ablation and a non‐contact continuous flow surface sampling probe/electrospray emitter for mass spectrometry based chemical imaging

This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid‐phase sample collection into a continuous flow surface sampling probe/electrospray emitter for mass spectrometry based chemical imaging. The flow probe/emitter device was placed in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collected was immediately aspirated into the probe and onto the electrospray emitter, ionized and detected with the mass spectrometer. Freehand drawn ink lines and letters and an inked fingerprint on microscope slides were analyzed. The circular laser ablation area was about 210 µm in diameter and under the conditions used in these experiments the spatial resolution, as determined by the size of the surface features distinguished in the chemical images, was about 100 µm. Published in 2011 by John Wiley & Sons, Ltd.     

On the application of an oxygen probe in chemical kinetics: The influence of the probe response on kinetic measurement

Membrance covered oxygen probes are frequently used to monitor the progress of chemical reactions involving dissolved oxygen. For reactions that are comparable in rate to the response of the oxygen probe it is difficult to obtain the correct kinetic constants directly from the probe signal with traditional kinetic data manipulation methods. In this article, we apply the method of impulse response function to describe the probe signal of an oxygen probe for three different types of simple chemical reactions. The impulse response function is obtained experimentally. Using the impulse response function we have obtained the relationships between the probe signal and the kinetic parameters of these reactions. The slow response of the probe has two effects on the kinetic curves of the reaction studied: a time-lag and distortion of the shape of the kinetic curve throughout the reaction. The latter effect becomes significant when the reaction is fast. Procedures to obtain the correct kinetic information from the oxygen probe signal are described. © 1995 John Wiley & Sons, Inc.     

Surface-potential reversibility of an amino-terminated self-assembled monolayer based on nanoprobe chemistry

Nanoprobe chemistry offers a promising approach for the construction of nanostructures consisting of organic molecules by employing the tip of a scanning probe microscope. In a previous report, we demonstrated that a nitroso-terminated surface on an organosilane self-assembled monolayer could be converted into an amino-terminated surface by applying such a nanoprobe electrochemical technique. This paper reports on surface-potential reversibility originating from a reversible chemical reaction between amino and nitroso groups. In addition, we demonstrate surface-potential memory based on this chemical reversibility. Amino-terminated SAMs were prepared from p-aminophenyl-trimethoxysilane through chemical vapor deposition. Surface potentials were acquired by Kelvin force microscopy. When scanning probe lithography was conducted with a gold tip at positive-bias voltages, the surface potential of the scanned area shifted dramatically in the negative direction. Scanning with negative-bias voltages led to positive shift in the surface potential of the scanned area. The surface potential could be recovered even after multiple scannings with positive and negative applied bias voltages. On the basis of this discovery, we also succeeded in demonstrating surface-potential memory via our nanoprobe electrochemical technique.     

Development of a new method for direct determination of selenium associated with atmospheric particulate matter using chemical modifiers and graphite probe furnace atomic absorption spectrometry

Direct determination of selenium on or in atmospheric particulate matter (APM) has been achieved using an integrated filtration and analysis system developed in our laboratories. The filtration (sampling) and analysis system consists of a porous electrographite plate which is used initially for the purpose of collecting APM and subsequently as a probe in graphite probe furnace atomic absorption spectrometry. Selenium produced a double peak when it was atomized from such an electrographite probe. Palladium nitrate+magnesium nitrate, as a mixed chemical modifier or ascorbic acid as a chemical modifier, eliminated the double peak. The addition of the chemical modifier(s) also removed the unpredictable changes in the peak-height and the peak-area absorbance which occurred from one atomization cycle to the next if the chemical modifier was not used. Precision of 5% RSD (peak-area absorbance) was obtained for an aqueous solution of selenium standard containing 1.25 ng of selenium with palladium nitrate+magnesium nitrate mixed chemical modifier, or ascorbic acid chemical modifer. The characteristic masses and the limits of detection for the aqueous solution of selenium standard with palladium nitrate+magnesium nitrate mixed chemical modifier are 27 and 41 pg (peak-area absorbance), respectively, and with ascorbic acid chemial modifier are 29 and 36 pg, respectively (peak-area absorbance). The results of analysis of the NIST (formerly National Bureau of Standards) Standard Reference Material No. 1648, Urban Particulate Matter, for selenium with palladium nitrate+magnesium nitrate mixed chemical modifier gave a recovery of 92%, and a precision of 10% RSD, and characteristic mass and the limit of detection of 20 and 37 pg, respectively.     

In situ evaluation of kinetic resolution catalysts for nitroaldol by rationally designed fluorescence probe

Development of effective chemical catalysts is a key concern in organic chemistry. Therefore, convenient screening systems for chemical catalysts are required, and although some fluorescence-based HTS systems have been developed, little attempt has been made to apply them to asymmetric catalysts. Therefore, we tried to develop a chiral fluorescence probe which can evaluate the reactivity and enantioselectivity of asymmetric catalysts. We focused on kinetic resolution catalysts as a target of our novel fluorescence probe, employing β-elimination following acylation of nitroaldol. Once the hydroxyl group of nitroaldol is acylated, β-elimination occurs immediately, affording nitro olefin. Therefore, we designed and synthesized a fluorescence probe with an asymmetric nitroaldol moiety. Its fluorescence intensity decreases dramatically upon β-elimination, so the fluorescence decrease is an indicator of the reaction yield. Thus, the enantioselectivity of kinetic resolution catalysts can be assessed simply by measuring the fluorescence intensities of the reaction mixtures of the two enantiomers; it is not necessary to purify the product. This fluorescence probe revealed that benzotetramisole is a superior catalyst for kinetic resolution of nitroaldol. Furthermore, we established an HTS system for asymmetric catalysts, using a fluorescence probe and benzotetramisole. To our knowledge, this is the first fluorescence-based HTS system for asymmetric catalysts.