复方钨酸盐对铜缓蚀协同作用的光电化学和SERS 研究

主要采用光电化学方法和表面增强拉曼光谱技术对具有环境友好性的钨酸盐与BTA复配使用对铜的缓蚀协同效应和作用机理进行了研究。实验表明Na2WO4对铜的缓蚀作用机理与BTA不同,在电位正向扫描过程中,光电流并不发生转型,其大小变化也不大;但在电位负向扫描过程中产生的阴极光电流峰值明显增大,缓蚀剂浓度越大,光电流越大,缓蚀效果越好,而Na2WO4与BTA复配使用时具有较好的协同效应,光电化学和SERS结果都说明其协同机理为两者都能对铜的缓蚀产生作用,前暑能促使电极表面产生的铜的氧化物增多;后者能与铜(Ⅰ)生成聚合物膜。     

Investigation of molybdate–benzotriazole surface treatment against copper tarnishing

The synergistic effect of benzotriazole (BTAH) and molybdate on the inhibition of copper tarnish was studied in this paper. The antitarnish treatment of copper was conducted with BTAH solution containing molybdate. The surface morphology observation and composition analysis were investigated by SEM with energy dispersive X‐ray (EDX) spectroscopy. The addition of molybdate improved the protection of BTAH significantly. The BTAH + molybdate treated copper specimen has higher N concentration in its surface. The structure of the protective film was studied by XPS and AES measurements. It was characterized to be a complex of Cu(I)BTA. The antitarnish effect is certified by the formation of the protective Cu(I)BTA film. Molybdate does not participate in the formation of the protective film. The presence of molybdate promotes the passivation of copper. This facilitates the stabilization of the cuprous oxide film, and strengthens the adsorption of BTAH. Copyright © 2008 John Wiley & Sons, Ltd.     

PCB酸性蚀刻液中缓蚀剂对厚铜线路制作的影响

以2-巯基苯并噻唑(2-MBT)、 苯并三氮唑(BTA)和苯氧基乙醇(MSDS)作为缓蚀剂, 研究了其加入在酸性蚀刻液后对PCB厚铜线路的缓蚀效果。通过接触角测试、电化学测试和蚀刻因子得出缓蚀状态,并结合扫描电子显微镜观察铜表面形貌。通过分子动力学计算和量子化学模拟分析缓蚀剂在铜表面的吸附机理。结果表明,2-MBT + MSDS与BTA + MSDS的分子结构可有效地平行吸附在铜表面,且吸附能高于单一缓蚀剂。加入了2-MBT + MSDS的蚀刻液,对厚度约为33 μm铜线路进行刻蚀,铜线路的蚀刻因子提高到6.59,可有效应用于PCB厚铜线路制作。     

铜电极在含苯并三唑的硼砂-硼酸缓冲溶液中的光电化学行为研究

用光电化学方法研究了铜电极在含苯并三唑(BTA)的硼砂-硼酸缓冲溶液中的光电化学行为。BTA能使铜电极的光响应由p-型转变为n-型。产生光响应的原因是铜电极表面的Cu2O膜。当BTA存在时由于BTA的作用致使电极表面Cu2O膜中共存着p-型和n-型区域, 电位正移和频率增加导致电极显示n-型光响应。     

金属螯合亲和膜吸附分离与纯化溶菌酶的研究(Ⅱ)──不同金属螯合亲和膜对溶菌酶的吸附性能

采用低温氧或氨等离子体法改性聚丙烯微孔膜,基于等离子体改性膜的活化、偶联及螯合过程的机理,制备了Fe³⁺,Ni²⁺,Cu²⁺和Zn²⁺等金属离子螯合亲和膜,并用于溶菌酶的吸-脱附实验.实验结果表明,Ni²⁺和Cu²⁺离子螯合亲和膜对溶菌酶具有较高的吸附量,螯合过程中采用氯化物盐溶液制得的膜对溶菌酶吸附量比采用硫酸盐溶液制得的膜的吸附量高.两种膜的重复吸-脱附性能相近,而Fe³⁺螯合亲和膜基本上不能用于重复吸-脱附实验.采用补充金属螯合离子,能部分恢复亲和膜对溶菌酶的吸附量,是实现亲和膜重复使用的有效方法.     

Long-term changes in the adsorptive properties of FEP separating funnels used in a mixed dithiocarbamate—Freon-TF extraction system

Liquid-liquid extraction methods for concentrating trace metals from sea water often involve chelation by dithiocarbamates as the first step. When fluorinated ethylene-propylene (FEP) separating funnels are used, hydrophobic adsorption of the dithiocarbamates on the inner walls can lead to a small (ca. 2%) loss of metal if any time is allowed between addition of the chelating mixture and extraction with Freon-TF. When the FEP funnels have been used extensively (mixing periods totalling 200 h) over a period of years, the adsorption of metals present in the 0–20 nmol l^?1 concentration range in sea water can be very significant (30–40% for Co, Ni, Cu; 60–70% for Zn, Mn, Fe). Under these conditions, the dependence of metal recovery on both initial metal concentration and concentration of chelating agent further suggests that metal adsorption is due to the presence of surface complexation sites involving the “aged” FEP surface and the dithiocarbamates. Ageing of the FEP surface thus limits the useful life of the FEP separating funnels used in a dithiocarbamate—Freon-TF extraction system.     

一氧化碳共吸附法确定叔丁胺分子在Cu(111)表面的吸附位

采用扫描隧道显微镜(STM)和密度泛函理论(DFT)研究了78 K时单个叔丁胺分子在Cu(111)表面的吸附位. 我们提出以共吸附的一氧化碳√3 ×√3 超结构为基底铜原子的标识方法, 确定了低覆盖度的叔丁胺分子在Cu(111)表面的吸附位为顶位. 而采用单个一氧化碳分子标识基底铜原子的位置, 同样得出了叔丁胺分子的吸附位为顶位. 此外, 还采用DFT计算叔丁胺分子在Cu(111)表面的优势吸附构型. 理论计算结果表明顶位吸附构型为能量最稳定的构型, 与实验结果相吻合.     

An electrochemical and SERS investigation of the influence of pH on the effectiveness of some corrosion inhibitors of copper

The adsorption on Cu of the corrosion inhibitors benzotriazole (BTA), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole and 2-mercaptobenzoxazole has been characterized in both neutral and acid chloride solutions using electrochemical techniques and surface enhanced Raman spectroscopy. The undissociated inhibitors and their anions are adsorbed simultaneously, the surface concentration ratio depending on the pH and electrode potential. At low pH, BTA is adsorbed weakly and it is displaced from surface sites by both Cl⁻ and the strongly adsorbed 2-mercaptobenzothiazole. These spectroscopic results explain the low corrosion inhibition due to BTA in acid solution.     

Cloud point extraction and separation of copper and lanthanoids using Triton X-100 with water-soluble p-sulfonatocalix[4]arene as a chelating agent

A method is presented for the cloud-point extraction and separation of copper and lanthanoid ions. A water-soluble calixarene, p-sulfonatocalix[4]arene (C4AS), is used as the chelating agent and Triton X-100 is chosen as the surfactant. The factors affecting the extraction efficiency, such as pH, the concentrations of Triton X-100 and C4AS, equilibration time and centrifugation time, were evaluated. The results demonstrate that there are different extraction behaviors for Cu(II) and Ln(III). Cu(II) can be separated from Ln(III) using C4AS as the chelating agent under weakly acidic conditions. The method may be used to remove trace copper from the lanthanoids.     

Thermodynamic stability of a bi-layer of copper nitride on Cu(100) surface

Ultrathin insulating films composed of a few atomic layers are being extensively used for controlling the electronic coupling of nanostructures deposited on a substrate. Ultrathin film, for example, a single layer of Cu(2)N deposited on a Cu(100) surface (known as Cu(2)N/Cu(100) surface) has been used to determine the spectral properties of nanomagnets using scanning tunneling spectroscopy. However, recent experiments that measure spin relaxation times in a single atom suggest that the single layer of Cu(2)N does not provide efficient electronic decoupling. In this work, we study the thermodynamic stability of a bi-layer of copper nitride on the Cu(100) surface. We calculate adsorption and co-adsorption energies of Cu and N as a function of their concentration on the Cu(2)N/Cu(100) surface using density functional theory. We find that the adsorption and co-adsorption energies of Cu and N on the Cu(2)N/Cu(100) surface are of the order of a few eV. This suggests that the bi-layer of copper nitride is thermodynamically stable on the Cu(100) surface. We also find that the work function of N-adsorbed Cu(2)N/Cu(100) increases with the N concentration, suggesting a better insulating character of the bi-layer of copper nitride on the Cu(100) surface.     

Surface enhanced Raman spectra of benzotriazole adsorbed on a copper electrode

The surface enhanced Raman spectrum of benzotriazole (BTAH) adsorbed on a copper electrode has been studied as a function of the potential applied to the electrode. The effect of pH and of the type of halide in the electrolyte solution has also been investigated. The presence of some complexes involving Cu(I), benzotriazole or benzotriazolate (BTA^-) and the halide has been characterized. The protective film formed on copper surface, in the presence of benzotriazole, has been identified as cuprous benzotriazolate [Cu(I)BTA].     

治疗铜中毒的新型高效络合剂对叔丁基硫杂杯[4]芳烃

以超分子化学基本原理为指导, 系统研究了对叔丁基硫杂杯[4]芳烃(简称TCA)作为受体对Cu²⁺(底物)的分子识别作用. 结果表明, TCA对Cu²⁺具有优异的识别能力, 且识别能力不受大量K⁺, Na⁺和Ca²⁺等共存离子的影响. TCA对Cu²⁺的识别作用优于驱铜药物2,3-二巯基丁二酸(DMSA). TCA对Cu²⁺的作用受竞争配体氨基酸的影响, 在血铜含量超标时, 人体正常浓度的氨基酸对TCA与Cu²⁺作用的影响很小; 而当Cu²⁺浓度降到正常血铜值时, 体内氨基酸的存在可使TCA的排铜效率降低, 避免发生铜的过多流失. TCA对Cu²⁺的作用优于对Zn²⁺的作用, 但共存离子Zn²⁺与Cu²⁺产生协同作用, 使TCA对Cu²⁺和Zn²⁺的萃取率均增加. 可通过降低萃取剂的浓度来减弱TCA与Zn²⁺的结合, 达到驱铜保锌的最佳效果. TCA有望发展为取代DMSA的更有效的驱铜药物.     

多重响应性复合介孔二氧化硅纳米微球的制备及其在抗腐蚀涂层上的应用

以正硅酸乙酯(TEOS)为硅源,制备介孔二氧化硅纳米微球(MSNs),利用原子转移自由基聚合(ATRP)技术在MSNs表面接枝聚甲基丙烯酸二甲胺乙酯(PDMAEMA)作为缓释开关,成为智能纳米容器(PDMAEMA-MSNs),装载防腐蚀剂-苯并三唑(BTA)验证其双重刺激响应性释放性能。采用透射电子显微镜(TEM)、热重分析(TGA) 、X-射线光电子能谱(XPS)以及傅里叶红外光谱(FT-IR)分析手段表征了MSNs的结构、形貌及表面功能化过程,并使用荧光光谱仪实时监测BTA在不同PH、温度下的释放过程。实验结果表明,智能纳米容器掺杂于SiOx/ZrOy中实现了BTA的双重响应性释放,形成Cu-BTA复合膜,起到铜金属防腐蚀的作用。     

A Study on the Adsorption of Benzotriazole on Copper in Hydrochloric Acid Using the Inflection Point of the Isotherm

This paper is a contribution to correlate benzotriazole (BTA) adsorption films on copper with BTA concentration in bulk solution with hydrochloric (HCl) acid. Three HCl concentrations were tested, 0.001, 0.005, and 0.01 M. Twelve BTA concentrations, from 1 × 10^–5 to 1 × 10^–1 M, were added to the HCl acid solution at four temperatures from 298 to 328 K. Commercial copper was used. Gravimetric measurements were performed after 3 h experimentation. The Frumkin isotherm gave the best fit to the experimental results. This result was based on the inflection point approach of the isotherm.     

新型侧链液晶聚醚螯合树脂的合成及其对水中Cu2 +的吸附性能研究

以环氧环己烷作为改性单体,通过环氧氯丙烷与环氧环己烷阳离子开环聚合获得分子量约为3000的共聚醚主链。然后以联苯为介晶基元、亚氨基二乙酸为末端螯合基团,成功合成了一种新型结构的侧链液晶聚醚螯合树脂。在对其结构鉴定以及基础物理性质测定的基础上,系统地研究了该树脂对水中Cu²⁺吸附的影响因素、再生性能、吸附选择性、吸附模型以及吸附动力学。结果表明,该树脂对Cu²⁺具有良好的吸附性能、再生性能和选择性,其对水中Cu²⁺的吸附为Langmuir单分子层吸附,吸附过程符合准二级动力学模型。     

吸附氢气后的钯团簇在氧化亚铜表面上的稳定性研究

为了探究吸附H2后的Pdn团簇在Cu2O（111）完整表面和铜缺陷表面上的稳定性,计算了负载在Cu2O（111）完整表面和铜缺陷表面上的Pdn（n=1-4）对H2分子的最稳定吸附结构;利用在给定H2压力和温度下Pdn / Cu2O表面吸附H2的相图揭示了Pdn团簇在Cu2O（111）两个表面的变化情况。结果表明,在吸附了H2分子以后,Pdn团簇更倾向于保持原有的结构,且随着Pd团簇的增大,吸附H2的数量也逐渐增长。     

O2和CN在铜活化闪锌矿(110)表面的吸附

采用基于密度泛函理论(DFT)的平面波赝势法模拟了O₂和CN分子在铜活化闪锌矿(110)表面的吸附. 结果表明: 铜活化后闪锌矿表面的铜原子3d轨道处于费米能级附近, 增强了闪锌矿表面的活性. 未活化闪锌矿表面不能吸附O₂, 活化后闪锌矿表面的铜原子和硫原子提供电子填入氧的反键π_2p^*轨道从而形成吸附键. CN分子吸附模拟表明, 铜活化增强了CN分子与闪锌矿表面的吸附作用. Cu原子d轨道与C原子反键p轨道作用形成反馈π键, 同时C原子s轨道与Cu原子sp轨道作用形成共价键; CN分子中N原子与闪锌矿表面S原子发生相互作用.     

Immobilized metal affinity composite membrane based on cellulose for separation of biopolymers

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Experimental investigation on the mechanism of chelation-assisted, copper(II) acetate-accelerated azide-alkyne cycloaddition

A mechanistic model is formulated to account for the high reactivity of chelating azides (organic azides capable of chelation-assisted metal coordination at the alkylated azido nitrogen position) and copper(II) acetate (Cu(OAc)(2)) in copper(II)-mediated azide-alkyne cycloaddition (AAC) reactions. Fluorescence and (1)H NMR assays are developed for monitoring the reaction progress in two different solvents, methanol and acetonitrile. Solvent kinetic isotopic effect and premixing experiments give credence to the proposed different induction reactions for converting copper(II) to catalytic copper(I) species in methanol (methanol oxidation) and acetonitrile (alkyne oxidative homocoupling), respectively. The kinetic orders of individual components in a chelation-assisted, copper(II)-accelerated AAC reaction are determined in both methanol and acetonitrile. Key conclusions resulting from the kinetic studies include (1) the interaction between copper ion (either in +1 or +2 oxidation state) and a chelating azide occurs in a fast, pre-equilibrium step prior to the formation of the in-cycle copper(I)-acetylide, (2) alkyne deprotonation is involved in several kinetically significant steps, and (3) consistent with prior experimental and computational results by other groups, two copper centers are involved in the catalysis. The X-ray crystal structures of chelating azides with Cu(OAc)(2) suggest a mechanistic synergy between alkyne oxidative homocoupling and copper(II)-accelerated AAC reactions, in which both a bimetallic catalytic pathway and a base are involved. The different roles of the two copper centers (a Lewis acid to enhance the electrophilicity of the azido group and a two-electron reducing agent in oxidative metallacycle formation, respectively) in the proposed catalytic cycle suggest that a mixed valency (+2 and +1) dinuclear copper species be a highly efficient catalyst. This proposition is supported by the higher activity of the partially reduced Cu(OAc)(2) in mediating a 2-picolylazide-involved AAC reaction than the fully reduced Cu(OAc)(2). Finally, the discontinuous kinetic behavior that has been observed by us and others in copper(I/II)-mediated AAC reactions is explained by the likely catalyst disintegration during the course of a relatively slow reaction. Complementing the prior mechanistic conclusions drawn by other investigators, which primarily focus on the copper(I)/alkyne interactions, we emphasize the kinetic significance of copper(I/II)/azide interaction. This work not only provides a mechanism accounting for the fast Cu(OAc)(2)-mediated AAC reactions involving chelating azides, which has apparent practical implications, but suggests the significance of mixed-valency dinuclear copper species in catalytic reactions where two copper centers carry different functions.     

In vivo copper-mediated free radical production: an ESR spin-trapping study

Copper has been suggested to facilitate oxidative tissue injury through a free radical-mediated pathway analogous to the Fenton reaction. By applying the electron spin resonance (ESR) spin-trapping technique, evidence for hydroxyl radical formation in vivo was obtained in rats treated simultaneously with copper and ascorbic acid or paraquat. A secondary radical spin-trapping technique was used in which the hydroxyl radical formed the methyl radical upon reaction with dimethylsulfoxide. The methyl radical was then detected by ESR spectroscopy as its adduct with the spin trap phenyl-N-t-butyl- nitrone (PBN). In contrast, lipid derived radical was detected in vivo in copper-challenged, vitamin E and selenium-deficient rats. These findings support the proposal that dietary selenium and vitamin E can protect against lipid peroxidation and copper toxicity. Since copper excreted into the bile from treated animals is expected to be maintained in the Cu(I) state (by ascorbic acid or glutathione), a chelating agent that would redox-stablilize it in the Cu(I) state was used to prevent ex vivo redox chemistry. Bile samples were collected directly into solutions of bathocuproinedisulfonic acid, a Cu(I)-stabilizing agent, and 2,2'-dipyridyl, a Fe(II)-stabilizing agent. If these precautions were not taken, radical adducts generated ex vivo could be mistaken for radical adducts produced in vivo and excreted into the bile.