维生素B12修饰电极及其催化氧还原性质的研究

发现给生素Ｂ１２能吸附在经阳极化处理的玻碳电极上，从而制成稳定的维生系Ｂ１２修饰玻碳电极详细研究了此电极的电化学性质。并发现此修饰电极能有效地催化分子氧的二电极还原。     

含锡AB5型非化学计量贮氢合金Ⅱ.电化学性能

研究了几种ＡＢ５非化学计量贮氢合金的电化学性能,及在低电流密度与电高流密度放电下了代元素对放电比容量、活化性能及循环寿命的影响。Ｓｎ,Ｃｏ,Ｍｎ的加入有利于提高合金的电化学氢容量,Ｌａ（ＮｉＳｎ）５．１４,Ｌａ（ＮｉＳｎＣｏ）５．１２和（ＮｉＳｎＭｎ）５．１２具有相同的电化学贮氢容量与活性特性。尽管Ｌａ（ＮｉＳｎ）５．１４大电流电性能优于Ｌａ（ＮｉＳｎＣｏ）５．１２和Ｌａ（ＮｉＳｎＭｎ）５．１２,     

Br^—对（TPP）Co电化学氧化还原行为影响研究

用微电极和薄层循环伏安（ＣＶ）技术研究了Ｂｒ＾－对四苯基钴卟啉（ＴＰＰ）Ｃｏ）在１，２－二氯乙烷（ＤＣＥ）中电化学行为的影响，发现在较高电位下，两个Ｂｒ＾－轴向配位的（ＴＰＰ）Ｃｏ（Ⅲ）（Ｂｒ＾－）２其一个Ｂｒ＾－发生脱落表现出（ＴＰＰ）Ｃｏ（Ⅲ）（Ｂｒ＾－）的行为特征，这被证明是Ｂｒ＾－的氧化所致证明了（ＴＰＰ）Ｃｏ（Ⅲ）Ｂｒ＾－在约０．１２Ｖ（ＳＣＥ）处还原，而（ＴＰＰ）Ｃｏ（Ⅲ）（Ｂｒ＾－）     

辅酶B12模型化合物的研究 α.RCo(salen) L(R=n-C3H7,i-C4H9;L=H2O,py,γ-pic)的电化学性质

用循环伏安法研究了辅酶Ｂ１２模型化合物ＲＣｏ（ｓａｌｅｎ）Ｌ（Ｒ＝ｎ－Ｃ３Ｈ７，ｉ－Ｃ４Ｈ９；Ｌ＝Ｈ２Ｏ，ｐｙ，γ－ｐｉｃ）的电化学行为，讨论了轴向碱基Ｌ对氧化还原电位的影响，结果表明：随着碱基Ｌ给电子能力的谱强，其氧化还原电位均发生负移。     

Pb／Pb^2＋和聚吡咯电极的交流电化学热研究

利用交流电化学热方法测定了Ｂｒ＾－／Ｂｒ２和Ｐｂ／Ｐｂ＾２＋电极的电极反应熵变，在动电位情况下利用该方法研究了聚吡咯电极反应，结果表明经碱溶液处理后聚吡咯电极的电化学活性明显下降，但从交流电化学热性质看，它还部分保留了原先聚吡咯电极的电极反应特性。     

水合希土硝酸盐与本并及单环己基－12－冠－4配合物的合成、性质及晶体结构

在乙腈介质中合成了苯并－１２－冠－４（简称Ｂ－１２－Ｃ－４）和单环己基－１２－冠－４（简称Ｃｙ－１２－Ｃ－４）的六种希土配合物：ＲＥ（ＮＯ３）３·Ｂ－１２－Ｃ－４（ＲＥ＝Ｐｒ，Ｇｄ，Ｙｂ，Ｌｕ），ＲＥ（ＮＯ３）３·Ｃｙ－１２－Ｃ－４（ＲＥ＝Ｌａ，Ｌｕ）．研究了它们的ＩＲ及１ＨＮＭＲ性质，并测定了四种单晶的结构．用ＩＮＤＯ法计算了Ｌｕ（ＮＯ３）３·Ｂ－１２－Ｃ－４，Ｌｕ（ＮＯ３）３·Ｃｙ－１２－Ｃ－４的电子结构．结果表明．Ｂ－１２－Ｃ－４与希土的配合物稳定性按Ｐｒ，Ｇｄ，Ｙｂ，Ｌｕ顺序减弱，并且Ｃｙ－１２－Ｃ－４与希土的配位能力大于Ｂ－１２－Ｃ－４．发现冠醚分子通过自身不同程度的扭曲，改变冠醚环空穴的大小，实现与不同大小的希土离子的配位作用．     

Ih对称性硼,碳原子簇化合物从头计算（Ⅱ）：C12B20,B12B2…

用价轨道双ζ型基，在Ｂ３２Ｈ３２＾２－等研究的基础上继续对Ｃ１２Ｂ２０．Ｃ１２Ｂ２０Ｈ３２及其正离子进行从头，并对照Ｃ２Ｂ３０、Ｂ３２和Ｂ＃２Ｈ３２＾２－的计算结果讨论其成键特性、稳定性及得电子反应活性。     

水合希土硝酸盐与本并及单环己基-12-冠-4配合物的合成、性质及晶体结构

在乙腈介质中合成了苯并－１２－冠－４（简称Ｂ－１２－Ｃ－４）和单环己基－１２－冠－４（简称Ｃｙ－１２－Ｃ－４）的六种希土配合物：ＲＥ（ＮＯ３）３·Ｂ－１２－Ｃ－４（ＲＥ＝Ｐｒ，Ｇｄ，Ｙｂ，Ｌｕ），ＲＥ（ＮＯ３）３·Ｃｙ－１２－Ｃ－４（ＲＥ＝Ｌａ，Ｌｕ）。研究了它们的ＩＲ及＾１ＨＮＭＲ性质，并测定了四种单晶的结构，用ＩＮＤＯ法计算了Ｌｕ（ＮＯ３）３·Ｂ－１２－Ｃ－４，Ｌｕ（ＮＯ３）３·Ｃｙ－１２－Ｃ     

PC／PBT共混体系的研究：（Ⅱ）PC,PBT熔融共混时的相容性

采用ＤＳＣ测定了一系列ＰＣ／ＰＢＴ熔融共混物的Ｔｇ，结果显示ＰＣ、ＰＢＴ是部分相容的两相体系，ＰＣ、ＰＢＴ之间的酯交换反应有利于相容性的提高。通过对ＰＣ、ＰＢＴ两相中各组分表观质量分数的计算，发现ＰＣ溶于ＰＢＴ的能力要比ＰＢＴ溶于ＰＣ的能力大。通过对ＰＣ、ＰＢＴ相互作用参数χ１２的计算，发现在所研究的范围内（ＰＣ含量为３０～７０％）ＰＣ、ＰＢＴ之间的相互作用参数χ１２略大于其临界相互作用参数（χ１２）ｃ，表明ＰＣ、ＰＢＴ在熔融共混时会发生相分离，亦即形成部分相容的两相体系     

恒电位法低浓度苯胺的电化学聚合研究

对恒电位法低浓度苯胺的电化学聚合进行了研究，推导了受扩散和电极反应同时控制的聚合电流方程式，成功地进行了验证，并对与聚合反应有关的电化学参量αＡ、ｋＢ，ＤＲ进行了测定。     

7-Decarboxymethyl-cobyrinates: vitamin B12-derivatives that lack the c-side chain

The synthesis of cobyrinic acid derivatives by reduction of dehydrocobyrinates is largely unexplored. It is, however, a rational path to B(12) analogues that lack specific substituents of the corrin moiety of natural B(12) derivatives. The partial syntheses of four epimeric 7-decarboxymethyl-cobyrinates is described, which is achieved by reduction of Δ7-dehydro-7-de[carboxymethyl]-cobyrinate with zinc or with the 'prebiotic' reducing agent formic acid. A direct and remarkably efficient route was found to 7-decarboxymethyl-cobyrinates, which are cobyrinic acid derivatives in which the c-side chain at ring B of vitamin B(12) is missing. The structures of the hexamethyl-7-decarboxymethyl-cobyrinates were characterized and the stereochemical and conformational properties at their newly saturated ring B were analyzed. The stereochemical outcome of the reduction was found to depend strongly on the reaction conditions. In 7-decarboxymethyl-cobyrinates, both peripheral carbon centres of ring B carry a hydrogen atom, and the characteristic quaternary carbon centre at C7 of the cobyrinic acid moiety of vitamin B(12) is lacking. The still highly substituted 7-decarboxymethyl-cobyrinates are readily dehydrogenated in the presence of dioxygen, furnishing 7-de[carboxymethyl]-Δ(7)-dehydro-cobyrinate as the common, unsaturated oxidation product. The noted stability of vitamin B(12) and of other Co(III)-cobyrinates in the presence of air is a consequence of their highly substituted corrin macrocycle, a finding of interest in the context of chemical rationalizations of the B(12) structure.     

Electrochemical and ultraviolet-visible spectroscopic studies on the interaction of deoxyribonucleic acid with vitamin B6

Studies on the interaction of DNA with vitamin B(6) were carried out with a DNA-modified electrode by electrochemistry and Ultraviolet-visible spectroscopy. The results showed that there exists the supra-molecule interaction between base groups on DNA and vitamin B(6) by forming hydrogen binding, the binding equilibrium constant of the interaction is equal to 115.3 M(-1), the binding ratio of nucleotide to vitamin B(6) is 5:1. Based on the electrochemical and Ultraviolet-visible spectrum studies the interaction mode of DNA with vitamin B(6) was explored.     

Electrochemical Characterization and Voltammetric Determination of Benzoyl Derivatives of Phenobarbital Using Glassy Carbon Electrode

The electrochemical behavior of a number of benzoyl barbiturates was studied using a glassy carbon electrode (GCE). The kinetics of the electrode process is determined, the contribution of physical adsorption to the electrochemical process is estimated, and the mechanism of the possible electrochemical reaction is proposed. It is shown that the electrochemical reduction potentials of benzoyl phenobarbital derivatives are determined by the LUMO energies, calculated by the B3LYP 6‐311+G method. It is established that the process is quasi‐reversible, complicated by adverse reactions. The influence of halogen type and its position in the benzoyl residue of the studied substances on the analytical signal is established. The effective values of the dissociation constants of various forms of benzoyl derivatives were calculated using the example of halonal, for which the values 3.16 ? 10^?8 and 6.31 ? 10^?12, respectively, were found.     

Synthesis and characterization of polypyrrole–magnetite–vitamin B12 hybrid composite electrodes

In this study vitamin B12 covered magnetite nanoparticles have been incorporated into a conducting polypyrrole. This polymer was electrochemically synthesized in the presence of the B12-coated magnetite. The adsorption of B12 was demonstrated by the decrease in absorbance of the vitamin in the supernatant liquid after B12 has been in contact with magnetite sol overnight. The composition of the layers was studied by the electrochemical quartz crystal microbalance technique during the polymerization. The slope of the mass change–charge curves indicate the incorporation of 27 m/m% magnetite and 15 m/m% B12. The redox transformation of the film in monomer- and nanoparticle-free solutions was also investigated by this method and the difference in the virtual molar masses of the moving species was evidenced. The morphology and the composition of the layers were characterized by scanning electron microscopy combined with energy dispersive X-ray microanalysis measurements, which latter proved the successful incorporation of the magnetic and bio-active components. The electrochemical behavior of the films unambiguously showed the complex redox activity of the composites and the current surplus were quantified by the redox capacity of the layers. These data show the doubling of the redox capacity in case of the hybrid material compared to the neat polymer. The successful enrichment of B12 can be exploited in the recently evidenced redox mediation process performed by a PPy/B12 film.     

Crystallography of vitamin B12 proteins

This review deals with results from crystallographic studies on proteins that interact with the essential micronutrient cobalamin (vitamin B12). Both B12-dependent enzymes and B12-transport proteins are described with an emphasis on structural aspects of cobalamin and its protein environment.     

二茂铁及其衍生物的电化学特性与结构理论研究

研究了二茂铁及其衍生物(甲酰二茂铁,乙酰二茂铁,甲醇二茂铁和乙酸二茂铁)的电化学行为,运用结构理论给出了二茂铁D5点群群轨道能级图与二茂铁衍生物的前线轨道能级图,得出在二茂铁分子结构中1e2(dx2-y2,dxy)与3a1(dz2,4s)分别属于分子前线轨道中的HOMO和LUMO。同时用密度泛函理论(DFT)在LANL2DZ基组水平上对其结构进行了全优化,得到了二茂铁及其衍生物前线最高被占轨道(HOMO)能量值,Fe原子净电荷,对其电化学行为与前线轨道能级相对大小进行了验证。     

7‐Decarboxymethyl‐cobyrinates: Vitamin B12‐Derivatives that Lack the c‐Side Chain

The synthesis of cobyrinic acid derivatives by reduction of dehydrocobyrinates is largely unexplored. It is, however, a rational path to B₁₂ analogues that lack specific substituents of the corrin moiety of natural B₁₂ derivatives. The partial syntheses of four epimeric 7‐decarboxymethyl‐cobyrinates is described, which is achieved by reduction of Δ7‐dehydro‐7‐de[carboxymethyl]‐cobyrinate with zinc or with the ‘prebiotic’ reducing agent formic acid. A direct and remarkably efficient route was found to 7‐decarboxymethyl‐cobyrinates, which are cobyrinic acid derivatives in which the c‐side chain at ring B of vitamin B₁₂ is missing. The structures of the hexamethyl‐7‐decarboxymethyl‐cobyrinates were characterized and the stereochemical and conformational properties at their newly saturated ring B were analyzed. The stereochemical outcome of the reduction was found to depend strongly on the reaction conditions. In 7‐decarboxymethyl‐cobyrinates, both peripheral carbon centres of ring B carry a hydrogen atom, and the characteristic quaternary carbon centre at C7 of the cobyrinic acid moiety of vitamin B₁₂ is lacking. The still highly substituted 7‐decarboxymethyl‐cobyrinates are readily dehydrogenated in the presence of dioxygen, furnishing 7‐de[carboxymethyl]‐Δ⁷‐dehydro‐cobyrinate as the common, unsaturated oxidation product. The noted stability of vitamin B₁₂ and of other Co^III‐cobyrinates in the presence of air is a consequence of their highly substituted corrin macrocycle, a finding of interest in the context of chemical rationalizations of the B₁₂ structure.     

Microband electrodes fabricated by screen printing processes: Applications in electroanalysis

A novel method for the simple and cheap manufacture of microband and multiple microband electrodes is described. The construction technique is based entirely on the screen printing of the surface of alumina tiles with conducting and insulating ink materials. The range of potentials over which the electrodes may be used has been determined by basic electrochemical studies. These electrode systems have been used successfully for the measurement of vitamin C, vitamin B(1) and paracetamol, which illustrates, their potential as useful tools in the field of electroanalysis.     

壳聚糖及其衍生物在分析化学中的应用

介绍了壳聚糖及其衍生物在分离富集、色谱固定相、电化学分析和生物传感器等方面的应用研究进展，并展望了其在分析化学中的应用前景。