第四周期过渡金属钼磷三元杂多化合物的氧化还原性质研究

研究了Keggin结构钼磷杂多化合物Na₅[PM(H₂O)Mo₁₁O₃₉]·nH₂O(M=Mn²⁺,Co²⁺,Ni²⁺,Cu²⁺,Zn²⁺在溶液中的氧化还原性质,发现环境的改变可对杂多阴离子的极谱半波电位产生影响,其影响程度的大小决定于过渡金属离子本身的性质。取代后的钼磷杂多阴离子的半波电位顺序为Ni²⁺>Co²⁺>Zn²⁺>Cu²⁺>Mn²⁺,pH值的变化影响氧化还原性质,并阐述了变价金属Cu²⁺对杂多阴离子氧化还原性质的影响.     

普鲁士蓝膜修饰电极循环伏安行为的研究

本文研究普鲁士蓝(PB)膜修饰电极的循环伏安行为,结果表明,膜中电活性中心间的相互作用导致PB膜电极的伏安行为偏离理想表面波.用有限扩散边界模型解释了高电位扫速下膜电极的伏安行为.在含钾离子的电解质溶液中测得PB膜中电荷传输扩散系数为10~(-9)～10~(-11)cm~2/s.     

A Photoluminescent Copper(I) Complex with an Exceptionally High CuII/CuI Redox Potential: [Cu(bfp)2]+ (bfp=2,9-bis(trifluoromethyl)-1,10-phenanthroline)

Unprecedented stabilization of the copper(I ) oxidation state is demonstrated for the complex cation [Cu(bfp)₂]⁺ ( 1 ) due to the steric and electronic effects of the CF₃ groups (E_1/2(Cu^II/Cu^I)=+1.55 V vs. SCE). The redox existence range of the copper(I ) species is remarkably high at 2.77 V. It is emissive in solution at room temperature and shows great potential as a photocatalyst; in the excited state it is a very potent photooxidant.     

Effect of Addition Groups on the Redox Properties of Fullerenes

采用循环伏安法和微分脉冲伏安法对比地研究了包括五种Ｃ６０的衍生物及四种Ｃ７０的衍生物的电化学性质．结果表明，推电子基团的引入使得富勒烯的氧化还原电位负移，这种负移的程度与加成基团的性质、个数和富勒烯的性质有关．对于Ｃ６０和Ｃ７０的单加成产物，负移的范围是０．０８～０．２０Ｖ．而对于Ｃ６０的双加成和三加成产物负移的范围分别为０．３０～０．３２Ｖ和０．５３～０．５８Ｖ．同时由于电位的负移大部分衍生物在低于＋１．５Ｖ（ｖｓ．ＳＣＥ）观察到了氧化峰，而Ｃ６０和Ｃ７０本身的氧化高达＋１．７Ｖ（ｖｓ．ＳＣＥ）．特别是对于Ｃ７０的双加成产物在＋０．４５Ｖ（ｖｓ．ＳＣＥ）出现了一个不可逆氧化峰，但是，对于同样加成基团的Ｃ６０双加成产物的氧化却在＋０．９０Ｖ（ｖｓ．ＳＣＥ），说明由于推电子基团的双加成引入，明显改变了Ｃ７０的电负性．     

铜的腺嘌呤络合物在悬汞电极表面上的吸附形态和氧化还原行为

本文详细地研究了铜的腺嘌呤（Ａｄｅ）络合物在悬汞电极（ＨＭＤＥ）表面上的吸附形态和伏安行为。实验结果揭示了单层吸附饱和之前有Ｃｕ＾＋Ａｄｅ，Ｃｕ２＾＋（Ａｄｅ）２形态的共吸附作用，随着电极表面的吸附浓度增长，Ａｄｅ络合物分子有从平面向垂直吸附的定向作用。哦的多层吸附和聚合作用发生在吸附分子垂直定向以后。本文还测定了有关电极过程的动力学参数。     

Redox behaviour of divalent metal saccharinates

Summary The electrochemical behaviour of a series of divalent metal saccharinates of stoichiometry [M ^II(sac)₂(H₂O)₄]·2H₂O was studied by cyclic voltammetry inDMF solutions using a glassy carbon electrode. The oxidation and the reduction of the metallic centers Fe(II) and Cu(II), respectively, is shown to occur in one electron-steps and to be quasireversible. The second electron transfer for the copper saccharinate is followed by decomposition of the complex associated with loss of the ligand and copper electrodeposition. Reduction of the ligand was observed for Ni(II), Fe(II), and Co(II) saccharinates at highly negative potential. On the contrary, oxidation or reduction peaks were not observed with sodium saccharinate. The uncoordinated ligand was inactive in the analyzed potential range.

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Elektrochemisches Verhalten zweiwertiger Metallsaccharinate

Zusammenfassung Das elektrochemische Verhalten einer Reihe zweiwertiger Metallsaccharinate der Stöchiometrie [M ^II(sac)₂(H₂O)₄]·2H₂O wurde inDMF mit Hilfe cyclischer Voltammetrie an Glaskohlenstoff-Elektroden untersucht. Die Oxidation bzw. Reduktion von Fe(II) und Cu(II) erfolgt durch einen Einelektronenprozeß und erwies sich als quasi-reversibel. Die zweite Elektronenübertragung wird im Falle des Kupfersaccharinats von einer Zersetzung des Komplexes begleitet, welche unter Ligandenverlust zur Abscheidung von Kupfer auf der Elektrode führt. Im Falle der Ni(II)-, Fe(II)- und Co(II)-Komplexe wurde eine Reduktion des Liganden bei sehr negativen Potentialen beobachtet. Dagegen wurden für Natriumsaccharinat keine Oxidations- oder Reduktionspeaks beobachtet; der unkomplexierte Ligand erwies sich im untersuchten Potentialbereich als inaktiv.

     

Rapid Method for Quantitative Determination of Proteolytic Activity with Cyclic Voltammetry

An alternative electrochemical method for the determination of proteolytic activity based on cyclic voltammetry of the electroactive probe ferricyanide (Fe(CN)₆^3?) on the gelatin film coated ITO electrodes was proposed. The gelatin film behaves as a kinetic barrier for Fe(CN)₆^3? and the proteolytic digestion of the gelatin film results an increase in the penetration of the Fe(CN)₆^3?. Thus, by the change of peak potential in cyclic voltammogram of Fe(CN)₆^3?, activity of the enzyme was determined.     

氰基乙烯基苯胺衍生物的电化学行为

本文利用循环伏安法研究了电子给-受体模型化合物——氰基乙烯基苯胺衍生物的电化学行为,并对推电子取代基团—NH_2和—N(CH_3)_2与吸电子取代基团氰基乙烯基对化合物电化学行为的影响进行了较为详细的讨论.提出了这些化合物的电氧化态和电还原态的结构,通过分析比较叔、仲和伯自由基对化合物电化学行为的影响,探讨了电极反应机理.     

Antioxidative Cassane Diterpenoids from the Seeds of Caesalpinia minax

Five new cassane diterpenoids, caesalmins I–M ( 1 – 5 ), and 23 known analogs were isolated from the seeds of Caesalpinia minax. Their structures were elucidated by spectroscopic methods and comparison with reported data. The antioxidant properties of 1 – 28 were determined by the method of oxygen radical absorbance capacity of fluorescein (ORAC‐FL), and 14 compounds exhibited good antioxidant activities with ORAC‐FL values of 2.24–4.89 Trolox equivalents. The structure? activity relationship of the active compounds was also discussed.     

Effects of HNO3 Concentration on the Electrochemical Behaviour of Lead

Summary.  The voltammogram of lead in nitric acid shows two well-defined anodic waves during the positive potential sweep. Upon reverse scanning, a wide current plateau followed by a cathodic peak associated with a shoulder at extreme negative potentials is observed. The overall behaviour was found to be quite complicated, and no simple relation between various variables like peak currents, peak potentials, and electrolyte concentrations could be found. The implications of these results with respect to the mechanisms of the electrode reactions are discussed. Received December 14, 2000. Accepted (revised) April 9, 2001     

牛红细胞铜锌超氧化物歧化酶（BESOD）在汞电极表面吸附行为的研究

牛红细胞铜锌超氧化物歧化酶（ＢＥＳＯＤ）在汞电极表面吸附行为的研究钱雯，孟庆国，罗勤慧，沈孟长（南京大学配位化学研究所，配位化学国家重点实验室南京，２１００９３）关键词铜锌超氧化物歧化酶，吸附，循环伏安，双阶跃计时电量超氧化物歧化酶是超氧离子（·Ｏ）...     

可溶性聚酰亚胺的电化学行为

聚酚亚胺（PI）以其优良的热稳定性、化学稳定性和作为优良的绝缘材料而被广泛应用于电子工业'．Haushalt。了和Kra。l。e等Li发现I'I膜在一定条件下可进行电化学反应．PI由于在电沉积等方面有潜在的应用价值,现已有一些这方面的研究工作卜一'．但所用的材料都是不溶性的PI,且用不同的方法制备PI薄膜修饰电极,因此所报道的PI在水或非水溶液中的电化学行为各不相同［'－'j．另外,以往的研究大都用一种商品化的l'I,而没有系统地研究PI结构对电化学行为的影响．本文报道了由相同的二胺和不同的二欧经化学环化制备的5种可溶性PI…     

Study on the Voltammetric Behaviour of Emulsifier OP across the Water-nitrobenzene Interface and its Application

Surfactantsareproducedworldwideinlargeamountsandwidelyusedinhouseholdorindustrialcleaners,cosmetic,researchlaboratories,etc.Manyelectfoanalyticalmethodsdevotedtosurfactantanalysishavebeenproposed',suchaspotentiometry,amperometry,tensammetry,electrocaPillarymeasurements.InthispaPer,emulsifierOP,asanewionophore,hasbeenintroducedtofacilitatemetaliontransferacrossaliquid/liquidinterface.ThevoltammetricbehaviourofemulsifierOP(EOP)whichfacilitatesthetransferofNa acrossthewater/nitrobebzene(w/nb)…     

Voltammetry of Electroinactive Species Using Quinone/Hydroquinone Redox: A Known Redox System Viewed in a New Perspective

Electrochemical behavior of p‐benzoquinone (Q), hydroquinone (H₂Q) and quinhydrone complex (QH) have been investigated in aqueous unbuffered solutions. The results revealed that in unbuffered solution the half wave potential of hydroquinone has a significant difference with quinone's half wave potential. It shown that, added acid in an unbuffered solution of Q, give rise to a new reduction peak at a more positive potential than original reduction peak of Q. The half‐peak potential of this new peak is dependent on acidity of added acid (pK_a) and its height is proportional to the acid concentration. Also, added base in an unbuffered solution of H₂Q, give rise to a new oxidation peak at a more negative potential than original oxidation peak of H₂Q. The half‐peak potential of this new peak is dependent on basicity of added base (pK_b) and its height is proportional to the base concentration. This paper shows new perspectives for a known system in aqueous unbuffered solutions, by means of voltammetric responses that can be exploited for the electrochemical investigation of non electroactive species such as HPO , HCO or CH₃COOH.     

芦丁与DNA相互作用的电化学研究

研究了芦丁与 DNA在 p H 5.72条件下相互作用的电化学行为。 DNA的存在能导致芦丁氧化还原峰电流降低 ,峰电位基本不变。通过测定 DNA引入前后的一些电化学参数 ,推测芦丁与 DNA在该条件下结合生成了一种非电活性的超分子化合物。针对该类型体系 ,推导出了一系列的方程 ,求得该超分子化合物的组成为 1∶ 1 ,结合常数 β=2 .49× 1 0 5mol- 1·L。     

Synthesis and Redox Behavior of Novel 9,10‐Diphenylphenanthrenes

The synthesis and electrochemical investigations of 9,10‐diphenylphenanthrene 2a and its derivatives 2b – 2e are reported. The cyclic voltammetry of derivatives 2a – 2c and 2e in different solvent/Bu₄NPF₆ electrolyte systems reveals that the redox properties are dependent on solvent, temperature, and sweep rate. The oxidation of 9,10‐diphenylphenanthrene 2a occurred as an irreversible process, while two fully reversible oxidation waves were observed for dimethoxy derivative 2c . The room‐temperature oxidation of brominated compound 2b is reversible, whereas AcO‐substituted phenanthrene 2e displayed a reversible oxidation peak only at low temperature. Furthermore, the electronic nature of the substituent affects the oxidation potentials. In the CH₂Cl₂‐based electrolyte system, the first oxidation potentials increase in the order 2c < 2e < 2b .     

Redox Properties of Isozazolo[60]fullerenes with Regard to Substituents and Molecular Structure

Abstract

A series of isoxazolo[60]fullerene derivatives 1(a-k), 5 and 6(l-n) have been synthesized by [2+3]cycloadditions of the corresponding nitriloxides to C₆₀. The phenyl-, 1,4- and 1,2-biphenyl substituents are substituted with electron donor groups in different distances and orientations in order to determine their influence on the redox properties of these fullerene derivatives. The redox- behavior was measured by cyclic voltammetry. In compounds 1b-g, 5l-n and 6l-n no significant shift relative to the reference compound la could be found. The insertion of an o-phenylene spacer between the isoxazoline ring and the phenyl ring substituted by donor groups in derivatives lh-k causes a shift of the first reduction potential by 30 mV (1h, 1k) and 60 mV (1i) towards more negative values compared to the reference 1a. Because of the o-phenylene spacer the plane of the donor-phenyl ring is forced into a close and parallel orientation to surface of the fullerene suitable for through-space interaction. This geometry was proven by X-ray structure determination of 1k.     

吡啶存在下（TPP）Co的电化学氧化还原行为研究

本文考究了吡啶对Ｃｏ在１，２－二氧乙烷中的电化学氧化还原行的影响，观察到当存在一定量Ｐｙ时，ＣＯ（Ⅲ）／Ｃｏ（Ⅱ）还原过程出现两个还原峰，分别在０．２５和－０．４０Ｖ两处。     

吖啶酮类衍生物的光电性质研究

测定了8个吖啶酮类衍生物的紫外吸收光谱、荧光光谱和荧光量子产率,以研究它们的结构与光学性质之间的关系,用循环伏安法测出它们各自的电子势．发现吖啶酮类衍生物都具有较高的电子亲和势,表现出比常用的电子传输材料2-(4-联苯基)-5-(叔丁苯基1—1,3,4-二唑(PBD)更容易被还原的优良电化学性能。     

Direct Observation of Radical Intermediates While Investigating the Redox Behavior of Thiamin Coenzyme Models

The redox behavior of “active aldehydes” 1 ⁻ derived from 3-benzylthiazolium salts and simple aldehydes in the presence of a base has been examined with low-temperature cyclic voltammetry and EPR spectroscopy. The highly negative oxidation potentials of 1 ⁻ and the spin distribution of the intermediate radicals 1 ^. indicate that the active aldehyde can act as an efficient electron mediator in thiamin-dependent enzymatic redox systems.