推拉电子取代基对二茂铁衍生笺性质及电子结构的影响

根据前线轨道理论分析３种具有推拉电子取代基的二茂铁衍生物循环伏安曲线，电子上光谱衣光谱电子化学行为，为给出了分子轨道能级图。实验结果表明，ＰⅡ有两对可逆氧化还原峰，Ｅ＾ｏｘ１，Ｅ＾ｏｘ２分别为０．３３，０．５９Ｖ，第一氧化态ＰⅡ＾＋（Ｄ－Ｆｃ＾＋－Ｒ）在６１３ｎｍ有强的ＬＭＣＴ（ｌｉｇａｎｄ－ｔｏ－ｍｅｔａｌ－ｃｈｇａｒｇｅ－ｔｒａｎｓｆｅｒ）带，是一种良好的光学特性氧化还原开关。ＰⅡ在３５４ｎｍ     

四核钼簇合物Mo_4S_4（μ－OAc）_2（dtp）_4在一些非水溶剂中的电化

利用循环伏安法测定了四核钼簇合物Ｍｏ_４Ｓ_４（μ－ＯＡｃ）_２（ｄｔｐ）_４在ＣＨ_３ＣＮ，ＤＭＦ，ＤＭＳＯ等溶剂中的氧化还原半波电位（Ｅ_（１／２）），对其氧化还原峰进行了归属，结果表明在ＣＨ_３ＣＮ中存在一个单电子的氧化过程和二个单电子的还原过程，而在ＤＭＦ和ＤＭＳＯ中只存在二个单电子的还原过程。同时还探讨了溶剂的ＤＮ数对该簇合物电化学性质的影响。     

Electrochemical Behavior of Chemically Prepared Ring-Substituted Polyanilines

聚邻甲苯胺（ＰＯＴ）、聚２，５二甲氧苯胺（ＰＤＭＡｎ）和聚间氯代苯胺（ＰＣｌＡｎ）由化学法合成而得，用它们的二甲基甲酰胺溶液在铂上成膜以制得聚合物修饰电极．循环伏安实验表明：在１ｍｏｌ／ＬＨ２ＳＯ４中，ＰＯＴ的氧化还原分两步进行，呈现两对氧化还原峰，ＰＤＭＡｎ只在较负的电位区呈现两对氧化还原峰，而ＰＣｌＡｎ不呈氧化还原活性．不同电位下的交流阻抗特征与循环伏安图相对应．三种聚合物膜电极在０．５ｍｏｌ／ＬＫ３［Ｆｅ（ＣＮ）６］溶液中的伏安图也证明铁氰离子的还原速度依ＰＯＴ＞ＰＤＭＡｎ＞ＰＣｌＡｎ的顺序而下降．环取代基的影响用电子效应和几何效应进行解释．可溶性聚苯胺便于制作大面积器件，环取代基对调节聚苯胺的电化学性能具有重要作用，值得进一步研究．     

四核钼簇合物Mo4S4（μ—OAc）2（dtp）4在一些非水溶剂中的电化学研究

利用循环伏安法测定了四核钼簇合物Ｍｏ４Ｓ４（μ－ＯＡｃ）２（ｄｔｐ）４在ＣＨ４ＣＮ，ＤＭＦ，ＤＭＳＯ等溶剂中的氧化还原半波电位（Ｅ１／２），对其氧化还原进行了归属，结果表明在ＣＨ３ＣＮ中存在一个单电子的氧化过程和二个单电子的还原过程，而在ＤＭＦ和ＤＭＳＯ中只存二个单电子的还原过程，同时还探讨了溶剂的ＤＮ数对该簇合物电化学性质的影响。     

CoTPP电化学催化原溴代环己烷的机理

以电化学循环伏安、现场ＥＳＲ电化学以及现场薄层电化学方法研究了电生Ｃｏ（Ｉ）ＴＰＰ与溴代五己烷的反机制。在ＤＭＦ中，Ｃｏ（Ⅱ）／Ｃｏ（Ⅰ）的氧化还原有明显的催化溴代环己烷还原的特片，反现场有自由基生成，反应产物之一是Ｃｏ－Ｃ键化合物，可以在１．３０Ｖ（ＳＣＥ）－电子还原，当存在ＣＨ２－ＣＨＣＮ时，。生成另一种Ｃｏ－Ｃ键化合物，该化合物在－１．１０Ｖ（ＳＣＥ）处一电子还原，证明溴代环己烷与Ｃｏ（Ｉ）     

杂多酸—聚（二烯丙基二甲基氯化铵）多层膜在4—氨基硫酚修饰金电极上的组装

通过电化学生长法在４－氨基硫酚自组装膜修饰金电极上制备了包含杂多酸（ＳｉＭｏ１１ＶＯ＾５－４０和聚合物阳极离子ＰＤＤＡ的多层膜修饰电极。用循环伏安法研究了该多层膜的电化学行为,结果表明,Ｍｏ的第３个还原峰随多层膜层数的增加显著增长,而另两个还原峰增长缓慢。该修饰电极的峰电位随ＰＨ的增加而线性负移,表明有氢离子参与杂多酸的氧化还原反应。该修饰电极对ＢｒＯ＾－３和ＮＨＯ２的还原反应有良好的催化作用,催化电流随着层数的增加而增长,并且Ｍｏ的第三个还原峰电流与ＣＲｒＯ＾－３有良好的线性关系。     

用循环伏安法研究烷氧基聚紫精的电氧化还原性能

利用循环伏安法研究了烷氧基聚紫精的电氧化还原性能，测定了它们的两步还原电位、峰电流和表现扩散系统（Ｄ），结果表明：Ｄ随着ＰＡｏＶ结构中所含醚键的增加而减小；并对第一步还原反应的可逆性进行了研究，发现第一步还原反应的可逆性优于第二步还原反应，同时证明电极反应是由扩散步骤控制的；ＰＡｏＶ具有良好的抗电疲劳性能；并研究了体系ｐＨ值和扫描范围对ＰＡｏＶ的电氧化还原性能的影响。     

化学合成环取代聚苯胺的电化学行为

聚邻甲苯胺（ＰＯＴ）、聚２,５ 二甲氧苯胺（ＰＤＭＡｎ）和聚间氯代苯胺（ＰＣｌＡｎ）由化学法合成而得,用它们的二甲基甲酰胺溶液在铂上成膜以制得聚合物修饰电极．循环伏安实验表明：在１ｍｏｌ／ＬＨ２ＳＯ４中,ＰＯＴ的氧化还原分两步进行,呈现两对氧化还原峰,ＰＤＭＡｎ只在较负的电位区呈现两对氧化还原峰,而ＰＣｌＡｎ不呈氧化还原活性．不同电位下的交流阻抗特征与循环伏安图相对应．三种聚合物膜电极在０．５ｍｏｌ／ＬＫ３［Ｆｅ（ＣＮ）６］溶液中的伏安图也证明铁氰离子的还原速度依ＰＯＴ＞ＰＤＭＡｎ＞ＰＣｌＡｎ的顺序而下降．环取代基的影响用电子效应和几何效应进行解释．可溶性聚苯胺便于制作大面积器件,环取代基对调节聚苯胺的电化学性能具有重要作用,值得进一步研究．     

甲醇在铂微粒修饰的聚硫堇电极上的电催化氧化

利用电化学循环伏安和现场ＦＴＩＲ反射光谱等技术研究了甲醇在铂微粒修饰的聚硫堇电极上的电催化氧化。结果表明，循环伏安法制备的铂微粒均匀分散于聚合物膜上，其粒径大小约为３０－１３０ｎｍ；复合修饰电极对甲醇电化学氧化呈现了较高的催化活性，其催化活性的大小依赖于Ｐｔ载量。现场ＦＴＩＲ光谱实验揭示了线性吸附的ＣＯ物种是甲醇在复合电极上氧化的唯一中间体，这种吸附的ＣＯ物种在复合修饰电极上更容易被氧化为最终产物     

中位－四（邻－硝基苯基）四苯并卟啉及其d过渡金属配合物的电化学性质

用微电极技术和循环伏安法研究了中位－四（邻硝基苯基）四苯并卟啉［ＴＰ（ｏ－ＮＯ＿２）ＴＢＰ］及其Ｆｅ（Ⅲ）、Ｃｏ（Ⅱ）、Ｎｉ（Ⅱ）和ｚｎ（Ⅱ）配合物在ＤＭＦ介质中的电化学行为。测得其电子转移过程的半波电位、标准速率常数及在ＤＭＦ中的扩散系数。并研究了吡啶轴向配位对Ｃｏ（Ⅱ）ＴＰ（ｏ－ＮＯ＿２）ＴＢＰ的氧化还原电位和速率的影响。提出了标题配位化合物在ＤＭＦ一吡啶混合溶剂中的电子转移机理。     

Spectroelectrochemical studies of poly-o-phenylenediamine Part 2. In situ UV—vis subtractive reflectance spectroscopy

In our previous paper, the phenazine-like structure of the poly-o-phenylenediamine (PoPD) and its three steady redox states have been revealed mainly by using in situ resonance Raman spectroscopy. It has also been shown that the semi-oxidized state of PoPD is the most stable state of PoPD, while the totally-oxidized state of PoPD is chemically unstable and can exist only at certain electrode potentials. In the present work, the more detailed reaction mechanism of a PoPD film in strong acid solution has been studied by using in situ UV—vis substractive reflectance spectroscopy. The semi-oxidized state and the totally-oxidized state of PoPD have electronic absorption bands around 300 nm, 430 nm, 500 nm and 300 nm, 450 nm, 530 nm, 735 nm respectively in the in situ steady state UV—vis subtractive reflectance spectra with respect to the reduced state of PoPD, which verifies once again that three redox states of PoPD exist in the redox process of PoPD. Moreover, the relative intensity between two oxidized states of PoPD at the maximum absorption wavelength (λ_max) reveals that only about one third of the semi-oxidized state of PoPD can be oxidized to the totally-oxidized state of PoPD. The in situ resonance Raman spectra and the cyclic voltammograms of PoPD display the same quantitative relationship. New absorption bands were observed in the in situ time-resolved UV—vis subtractive reflectance spectra with appropriate time resolutions, which illustrate the dynamic structure changes of PoPD in its redox process. These intermediate states of PoPD are more unstable than its three redox states.     

The electrochemistry of antibody-modified conducting polymer electrodes

The modification of conducting polymer electrodes with antibodies (i.e. proteins) by means of electrochemical polymerization is a simple step that can be used to develop an immunological sensor. However, the electrochemical processes involved leading to the generation of analytical signals by the sensor have not been fully investigated. In this work, we report on the characterization of the interaction between an antigen, human serum albumin (HSA) and an antibody-immobilized polypyrrole electrode (such as anti-HSA) using cyclic voltammetry (CV) and impedance spectroscopy. This interaction was monitored using electrochemical impedance spectroscopy at three different potentials. The potentials correspond to the three redox states of the electroconducting polymer (i.e. reduced, doped and overoxidized states). Evidence from the CV experiments confirmed that there was a shift in the potential, which was found to be proportional to the concentration. Both the CV and the impedance experiments indicated that this potential-dependent shift could be attributed to antibody–antigen (Ab–Ag) binding.     

Charge‐Transfer Interactions in Tris‐Donor–Tris‐Acceptor Hexaarylbenzene Redox Chromophores

Symmetric‐ and asymmetric hexaarylbenzenes (HABs), each substituted with three electron‐donor triarylamine redox centers and three electron‐acceptor triarylborane redox centers, were synthesized by cobalt‐catalyzed cyclotrimerization, thereby forming compounds with six‐ and four donor–acceptor interactions, respectively. The electrochemical‐ and photophysical properties of these systems were investigated by cyclovoltammetry (CV), as well as by absorption‐ and fluorescence spectroscopy, and compared to a HAB that only contained one neighboring donor–acceptor pair. CV measurements of the asymmetric HAB show three oxidation peaks and three reduction peaks, whose peak‐separation is greatly influenced by the conducting salt, owing to ion‐pairing and shielding effects. Consequently, the peak‐separations cannot be interpreted in terms of the electronic couplings in the generated mixed‐valence species. Transient‐absorption spectra, fluorescence‐solvatochromism, and absorption spectra show that charge‐transfer states from the amine‐ to the boron centers are generated after optical excitation. The electronic donor–acceptor interactions are weak because the charge transfer has to occur predominantly through space. Moreover, the excitation energy of the localized excited charge‐transfer states can be redistributed between the aryl substituents of these multidimensional chromophores within the fluorescence lifetime (about 60 ns). This result was confirmed by steady‐state fluorescence‐anisotropy measurements, which further indicated symmetry‐breaking in the superficially symmetric HAB. Adding fluoride ions causes the boron centers to lose their accepting ability owing to complexation. Consequently, the charge‐transfer character in the donor–acceptor chromophores vanishes, as observed in both the absorption‐ and fluorescence spectra. However, the ability of the boron center as a fluoride sensor is strongly influenced by the moisture content of the solvent, possibly owing to the formation of hydrogen‐bonding interactions between water molecules and the fluoride anions.     

Voltammetric and drift spectroscopy investigation in dithiophosphinate-chalcopyrite system

The mechanism of dithiophosphinate (DTPI) adsorption on chalcopyrite was investigated by diffuse reflectance Fourier transformation (DRIFT) spectroscopy and by cyclic voltammetry (CV) at various pHs. CV experiments showed that the redox reactions occurred at a certain degree of irreversibility on the chalcopyrite surface in the absence of a collector due to preferential dissolution of iron ions in slightly acid solution and irreversible surface coverage by iron oxyhydroxides in neutral and alkaline solutions. In the presence of DTPI, CV experiments failed to identify the type of the adsorbed DTPI species and electrochemical processes occurring on chalcopyrite due to formation of an electrochemically passive surface layer preventing electron transfer. However, DRIFT spectroscopy tests showed this passive layer to be mainly CuDTPI + (DTPI)2. Both CV and DRIFT spectroscopy established that the activity of collector species decreased with increasing pH due to formation of stable hydrophilic metal oxyhydroxides on the chalcopyrite surface.     

Charge-transfer interactions in tris-donor-tris-acceptor hexaarylbenzene redox chromophores

Symmetric- and asymmetric hexaarylbenzenes (HABs), each substituted with three electron-donor triarylamine redox centers and three electron-acceptor triarylborane redox centers, were synthesized by cobalt-catalyzed cyclotrimerization, thereby forming compounds with six- and four donor-acceptor interactions, respectively. The electrochemical- and photophysical properties of these systems were investigated by cyclovoltammetry (CV), as well as by absorption- and fluorescence spectroscopy, and compared to a HAB that only contained one neighboring donor-acceptor pair. CV measurements of the asymmetric HAB show three oxidation peaks and three reduction peaks, whose peak-separation is greatly influenced by the conducting salt, owing to ion-pairing and shielding effects. Consequently, the peak-separations cannot be interpreted in terms of the electronic couplings in the generated mixed-valence species. Transient-absorption spectra, fluorescence-solvatochromism, and absorption spectra show that charge-transfer states from the amine- to the boron centers are generated after optical excitation. The electronic donor-acceptor interactions are weak because the charge transfer has to occur predominantly through space. Moreover, the excitation energy of the localized excited charge-transfer states can be redistributed between the aryl substituents of these multidimensional chromophores within the fluorescence lifetime (about 60?ns). This result was confirmed by steady-state fluorescence-anisotropy measurements, which further indicated symmetry-breaking in the superficially symmetric HAB. Adding fluoride ions causes the boron centers to lose their accepting ability owing to complexation. Consequently, the charge-transfer character in the donor-acceptor chromophores vanishes, as observed in both the absorption- and fluorescence spectra. However, the ability of the boron center as a fluoride sensor is strongly influenced by the moisture content of the solvent, possibly owing to the formation of hydrogen-bonding interactions between water molecules and the fluoride anions.     

ELECTROCHEMICAL COPOLYMERIZATION OF DIBENZOFURAN AND 3-METHYLTHIOPHENE IN BORON TRIFLUORIDE DIETHYL ETHERATE

The copolymerization of dibenzofuran(DBF)and 3-methylthiophene(MET)was successfully achieved electrochemically by direct anodic oxidation of the monomer mixtures in boron trifluoride diethyl etherate.The effects of applied polymerization potential and the monomer concentration ratios on the copolymerization were investigated by linear sweep voltammetry and cyclic voltammetry(CV).The structure of copolymer films were investigated by UV-Vis,infrared spectroscopy,thermal analysis.As-formed novel copolymers ...     

三维有序金掺杂纳米TiO_2修饰电极用于抗肿瘤药物与DNA相互作用的研究

利用模板法在氧化铟锡(ITO)电极表面制备了三维有序多孔结构的金掺杂纳米Ti O2薄膜修饰电极(3DOM GTD/ITO),并在此修饰电极上成功固定小牛胸腺DNA(ct DNA),从而构建了一种新型的DNA生物传感器(DNA/3DOM GTD/ITO),并通过透射电镜(TEM)、扫描电镜(SEM)对修饰电极的表面形貌进行表征。采用电化学交流阻抗(EIS)法研究了ct DNA在3DOM GTD/ITO修饰电极表面的固定情况,结果表明,ct DNA已被成功地固定在3DOM GTD/ITO修饰电极表面。采用循环伏安法、微分脉冲伏安法等电化学方法研究了抗肿瘤药物槲皮素(Qu)在3DOM GTD/ITO修饰电极表面的电化学性质及与ct DNA的相互作用。结果表明,Qu在3DOM GTD/ITO修饰电极表面有1对准可逆的氧化还原峰,其氧化还原反应为2电子和2质子的转移过程。Qu可与固定在修饰电极上的ct DNA发生较强的结合作用,其结合常数(K)为3.61×106L/mol。循环伏安实验、紫外-可见吸收光谱、分子荧光光谱、圆二色性光谱均表明Qu与ct DNA之间的相互作用模式为嵌插作用。Qu与ct DNA的碱基结合具有序列选择性,对Qu与聚(d G-d C)及聚(d A-d T)的结合常数进行计算,得到结合常数比K(d G-d C)/K(d A-d T)=3.5,表明Qu与ct DNA发生嵌插作用时更倾向于结合在GC富集区域。     

Electrochemical impedance studies of the undoping process of platinum phthalocyanine charge transfer microcrystals

Platinum phthalocyanine (PtPc) microcrystal films undergo three successive electrochemical oxidations. Each of these processes is associated with anion insertion or doping. The reverse process of anion insertion, undoping, has been investigated using electrochemical impedance spectroscopy and in-situ UV–vis spectroscopy. The impedance theory of conductive polymer films developed by Vorotyntsev et al. is applicable to this process. The kinetics of the undoping process depend upon the previous oxidative treatment, and thus the doping level. Three different states of the film can be demarcated, depending on the degree of oxidation (and thus the degree of doping) of the PtPc film. These are called the lightly doped, the conductive and the over-doped state, respectively. For lightly doped films, the film conductivity, the redox capacitance, the diffusion coefficient for charge transport and the rate of electrochemical reaction all decrease with decreasing potential. The film conductivity depends upon the concentration of free charge carriers. For the more highly doped conductive film, all of the above parameters are greatly enhanced, and the electrochemical reaction is accelerated and proceeds at a very high rate. The potential dependence of the redox capacitance and the diffusion coefficient depends on the type of anion. During undoping at 0 V, unusually high diffusion coefficients with a magnitude of order 10⁻² cm² s⁻¹ are observed and are attributed to the strong interactions between the electronic and ionic carriers during the phase transformation. For the over-doped film, undoping leads to an increase in the film conductivity and electrochemical reaction rate. The potential dependence of the redox capacitance and diffusion coefficients for charge transport implies strong interactions within the film. Hypsochromic shifts in UV–vis spectra with decreasing potential indicate conformational relaxation during the undoping process. SEM investigation confirms that the doped film swells during the de-doping process.     

含末端炔基的Salen型金属配合物的合成、表征及性质

设计合成了新型含有末端炔基的Salen型配体H2Ln及其系列金属配合物MLn(n=1,2;M=Ni,Cu,Mn),并用氢核磁共振(1H NHR)谱、电喷雾质谱(ESI-MS)、元素分析(EA)、傅里叶变换红外(FT-IR)光谱和紫外-可见(UV-Vis)光谱等对各目标化合物进行了表征.采用循环伏安法研究了配体及其金属配合物的电化学氧化还原性质.研究发现,配体除H2L1外均在测试范围内出现特征的亚胺氧化还原峰.镍和铜的配合物均经历了两个单电子的氧化还原过程;锰的配合物均出现由Mn(III)/Mn(II)产生的一对氧化还原峰,该过程为准可逆的单电子过程.H2Ln及MLn的溶液摩尔电导率数据显示,各目标化合物为弱电解质,具有一定的导电性.     

聚邻苯二胺膜电极的性能及其对苯醌还原动力学的影响

利用循环伏安法和原位红外反射光谱法研究了pH=7.0的磷酸盐缓冲溶液中聚邻苯二胺(PPD)膜电极的电化学行为。在比0.0V(SCE)负的电位区,PPD呈现氧化还原活性,氧化还原过程伴有H₂PO₄^-离子的嵌入和脱出,证明聚合物带有正电荷。苯醌在该膜电极上的还原反应发生在PPI)的电化学活性电位区内。旋转圆盘电极实验表明,苯配可渗入膜内并与聚合物交换电子。根据PPD为导电聚合物的模型分析了膜电极上苯配还原的动力学并讨论了对其影响的因素。