扫描电化学显微镜在光电化学研究中的应用

深入研究各种光电化学反应过程的机理和反应动力学性质等对提升光电转换效率、发展绿色高效光伏能源器件具有重要意义.扫描电化学显微镜(SECM)是一种具有高时空分辨率的电化学扫描探针显微镜技术,不仅可以研究光电催化反应的机理和动力学性质,还可以通过光电流反馈模式进行组合成像,实现光电催化剂的性能评估和优选,近年来逐渐成为光电化学研究领域微区观测和反应动力学研究的重要技术手段.本综述系统介绍了SECM在光电化学研究中的应用,首先介绍用于光电化学研究的SECM的实验装置、工作原理和工作模式,然后对SECM在光合作用、光诱导电荷转移、电致化学发光、光解水、太阳能电池等光电化学研究领域的应用进行了详细介绍,最后展望了SECM在光电化学研究领域中的应用发展方向.     

扫描电化学显微镜在生物医学领域的应用研究进展

研究病变细胞和组织的异常表现可为理解重大疾病发生发展的病理机理和新型药物筛选提供重要参考.扫描电化学显微镜(Scanning electrochemical microscopy,SECM)是一种基于电化学原理的扫描探针显微镜,通过记录探针在样品表面扫描时的电流或电位等信息,对活细胞的形态和多种化学信息进行原位、实时、精准表征.近10年来,SECM在重大疾病相关的细胞、细胞球和微组织层次的应用研究得到快速发展.本文从与疾病相关的SECM研究角度入手,分别从单细胞、细胞球和微组织层次小结SECM近10年来在生物医学领域的应用研究进展.首先介绍SECM的仪器组成、探针种类和工作模式,其次分别介绍SECM在神经细胞、心肌细胞和肿瘤细胞的应用进展,之后介绍SECM近期在细胞球和微组织的最新应用,最后提出并展望SECM技术在生物医学领域进一步应用所面临的挑战和发展方向.     

SECM基本原理及其在金属腐蚀中的应用

扫描电化学显微镜（SECM）是一种具有较高空间分辨率的化学显微镜,在成像和动力学研究已经广泛应用. 本文简要介绍SECM基本原理,综述2009年以来SECM在腐蚀方面的应用,包括扫描成像和异相转移电子化学活性的研究,并简要介绍了作者课题组在SECM方面的研究工作,展望SECM在腐蚀研究的应用.     

扫描电化学显微镜在电催化氧反应研究中的应用

本综述首先简单介绍了扫描电化学显微镜的基本概况,尤其是不同的工作模式. 其次,有针对性地介绍了SECM的不同工作模式在氧还原和水解析氧反应相关研究中的应用. 最后,对扫描电化学显微镜未来在新能源转换存储系统研究领域的应用进行了展望.     

扫描电化学显微镜及其在界面电化学研究中的应用

对扫描电化学显微镜(Scanning Electrochemical Microscope，SECM)的发展及其在界面电化学中的研究应用进行了评述。介绍了SECM的工作原理以及常用的操作模式，并对SECM在液／液界面、固／液界面等方面的应用进行了总结。     

扫描电化学微探针的发展及其在局部腐蚀研究中的应用

简要概述当前国内外具有空间分辨能力的扫描微探针技术及其在腐蚀研究中的应用,包括扫描微电极技术(SMET)、扫描电化学显微镜(SECM)、原子力显微镜(AFM)、扫描Kelvin探针技术(SKP)等,其中SMET、SECM、SKP及局部交流阻抗技术可直接测定腐蚀电极表面或界面电化学不均一性的分布图像,而原子力显微镜技术则是通过分子间作用力从纳米尺寸测量腐蚀过程表面形貌的变化.文中侧重介绍作者近年先后建立的具有微米空间分辨度的电化学微探针技术,并利用各种扫描探针技术研究金属/溶液界面电化学不均一性及其局部腐蚀过程.研究表明,空间分辨电化学方法的发展及应用,加深了人们对金属表面和金属/溶液界面电化学不均一性,特别是金属局部腐蚀发生、发展及过程机理的认识.     

金属纳米电极的制备、表征及其在电化学测量中的应用

本文简要介绍了各种金属纳米电极的制备及表征方法。结合我们自己的工作,重点介绍了纳米电极在电化学反应动力学参数测量及扫描电化学显微镜(SECM)中的应用,并对其发展前景进行了展望。引用文献78篇。     

扫描电化学显微镜在电催化表面反应分析中的现代应用

能源和环境问题成为制约未来可持续发展的关键问题之一,因此,针对不同电催化反应设计电催化剂变得越来越重要.电催化剂因其能量效率高、制备简单和易操作等优点,而应用于可再生能源的相关反应(如水分解和人工光合作用)中.明确不同反应电催化剂的设计原理,深入理解其在相关反应中的催化机理,可进一步优化催化剂性能.本文综述了扫描电化学显微镜(SECM)应用于电催化反应的历程、关键方法以及一些代表性的工作,阐明了电催化剂的工作机理以推进电催化剂的设计.本文还介绍了为提高SECM的空间分辨率而尝试的纳米尺寸电极方面的新进展,分享了纳米电极在以前研究无法涉及的单一催化实体方面的应用.     

数字图像处理技术在扫描电化学显微镜中的应用

扫描电化学显微镜(SECM)使用超微电极作为探针,由于发生在探针电极上的氧化还原反应是一个扩散过程,探针电极在快速移动过程中会对扩散过程产生影响,导致SECM图像变得不清晰。本研究采用Lo G算法与NEDI插值算法相结合的图像处理技术对获得的SECM图像进行处理,Lo G算法可以提高SECM图像的清晰度,但会导致图像中部分边缘信息丢失,利用基于边缘导向插值的NEDI算法对后续图像进行处理,可以很好地解决这个问题。采用离子溅射方法制备了金叉指电极和金点阵电极两种基底,对金叉指电极基底、金点阵电极基底和印有指纹的ITO基底进行了SECM成像,通过对3种基底的SECM原始图像、Lo G变换后的图像和NEDI插值后的图像进行比较分析,表明Lo G算法与NEDI插值算法结合在一起的图像处理技术可以明显提高SECM图像的清晰度和分辨率。     

“电极/溶液”界面的椭圆偏振测量技术研究进展

椭圆偏振测量技术是通过解析偏振光束在界面上或薄膜中反射或透射时偏振状态的变化,获取界面或薄膜的厚度、复折射率等性质的一种光学方法,是一种高灵敏度、非破坏性的原位实时表征技术,被广泛应用于“电极/溶液”界面的研究. 本文简要介绍了椭圆偏振测量技术的基本原理及其最新发展,并着重评述了能源电化学、材料电化学、电分析与生物电化学等领域中,应用椭圆偏振测量技术研究“电极/溶液”界面的现状.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.